/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2023 Cppcheck team. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ /** * @brief This is the ValueFlow component in Cppcheck. * * Each @sa Token in the token list has a list of values. These are * the "possible" values for the Token at runtime. * * In the --debug and --debug-normal output you can see the ValueFlow data. For example: * * int f() * { * int x = 10; * return 4 * x + 2; * } * * The --debug-normal output says: * * ##Value flow * Line 3 * 10 always 10 * Line 4 * 4 always 4 * * always 40 * x always 10 * + always 42 * 2 always 2 * * All value flow analysis is executed in the ValueFlow::setValues() function. The ValueFlow analysis is executed after * the tokenizer/ast/symboldatabase/etc.. The ValueFlow analysis is done in a series of valueFlow* function calls, where * each such function call can only use results from previous function calls. The function calls should be arranged so * that valueFlow* that do not require previous ValueFlow information should be first. * * Type of analysis * ================ * * This is "flow sensitive" value flow analysis. We _usually_ track the value for 1 variable at a time. * * How are calculations handled * ============================ * * Here is an example code: * * x = 3 + 4; * * The valueFlowNumber set the values for the "3" and "4" tokens by calling setTokenValue(). * The setTokenValue() handle the calculations automatically. When both "3" and "4" have values, the "+" can be * calculated. setTokenValue() recursively calls itself when parents in calculations can be calculated. * * Forward / Reverse flow analysis * =============================== * * In forward value flow analysis we know a value and see what happens when we are stepping the program forward. Like * normal execution. The valueFlowForward is used in this analysis. * * In reverse value flow analysis we know the value of a variable at line X. And try to "execute backwards" to determine * possible values before line X. The valueFlowReverse is used in this analysis. * * */ #include "valueflow.h" #include "analyzer.h" #include "astutils.h" #include "calculate.h" #include "checkuninitvar.h" #include "config.h" #include "errorlogger.h" #include "errortypes.h" #include "findtoken.h" #include "forwardanalyzer.h" #include "infer.h" #include "library.h" #include "mathlib.h" #include "path.h" #include "platform.h" #include "programmemory.h" #include "reverseanalyzer.h" #include "settings.h" #include "smallvector.h" #include "sourcelocation.h" #include "standards.h" #include "symboldatabase.h" #include "timer.h" #include "token.h" #include "tokenlist.h" #include "utils.h" #include "valueptr.h" #include "vfvalue.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // IWYU pragma: keep #include #include #include #include #include static void bailoutInternal(const std::string& type, TokenList &tokenlist, ErrorLogger *errorLogger, const Token *tok, const std::string &what, const std::string &file, int line, std::string function) { if (function.find("operator") != std::string::npos) function = "(valueFlow)"; std::list callstack(1, ErrorMessage::FileLocation(tok, &tokenlist)); ErrorMessage errmsg(callstack, tokenlist.getSourceFilePath(), Severity::debug, Path::stripDirectoryPart(file) + ":" + std::to_string(line) + ":" + function + " bailout: " + what, type, Certainty::normal); errorLogger->reportErr(errmsg); } #define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __func__) #define bailout(tokenlist, errorLogger, tok, what) bailout2("valueFlowBailout", tokenlist, errorLogger, tok, what) #define bailoutIncompleteVar(tokenlist, errorLogger, tok, what) bailout2("valueFlowBailoutIncompleteVar", tokenlist, errorLogger, tok, what) static std::string debugString(const ValueFlow::Value& v) { std::string kind; switch (v.valueKind) { case ValueFlow::Value::ValueKind::Impossible: case ValueFlow::Value::ValueKind::Known: kind = "always"; break; case ValueFlow::Value::ValueKind::Inconclusive: kind = "inconclusive"; break; case ValueFlow::Value::ValueKind::Possible: kind = "possible"; break; } return kind + " " + v.toString(); } static void setSourceLocation(ValueFlow::Value& v, SourceLocation ctx, const Token* tok, SourceLocation local = SourceLocation::current()) { std::string file = ctx.file_name(); if (file.empty()) return; std::string s = Path::stripDirectoryPart(file) + ":" + std::to_string(ctx.line()) + ": " + ctx.function_name() + " => " + local.function_name() + ": " + debugString(v); v.debugPath.emplace_back(tok, std::move(s)); } static void changeKnownToPossible(std::list &values, int indirect=-1) { for (ValueFlow::Value& v: values) { if (indirect >= 0 && v.indirect != indirect) continue; v.changeKnownToPossible(); } } static void removeImpossible(std::list& values, int indirect = -1) { values.remove_if([&](const ValueFlow::Value& v) { if (indirect >= 0 && v.indirect != indirect) return false; return v.isImpossible(); }); } static void lowerToPossible(std::list& values, int indirect = -1) { changeKnownToPossible(values, indirect); removeImpossible(values, indirect); } static void changePossibleToKnown(std::list& values, int indirect = -1) { for (ValueFlow::Value& v : values) { if (indirect >= 0 && v.indirect != indirect) continue; if (!v.isPossible()) continue; if (v.bound != ValueFlow::Value::Bound::Point) continue; v.setKnown(); } } static bool isNonConditionalPossibleIntValue(const ValueFlow::Value& v) { if (v.conditional) return false; if (v.condition) return false; if (!v.isPossible()) return false; if (!v.isIntValue()) return false; return true; } static void setValueUpperBound(ValueFlow::Value& value, bool upper) { if (upper) value.bound = ValueFlow::Value::Bound::Upper; else value.bound = ValueFlow::Value::Bound::Lower; } static void setValueBound(ValueFlow::Value& value, const Token* tok, bool invert) { if (Token::Match(tok, "<|<=")) { setValueUpperBound(value, !invert); } else if (Token::Match(tok, ">|>=")) { setValueUpperBound(value, invert); } } static void setConditionalValue(ValueFlow::Value& value, const Token* tok, MathLib::bigint i) { assert(value.isIntValue()); value.intvalue = i; value.assumeCondition(tok); value.setPossible(); } static void setConditionalValues(const Token* tok, bool lhs, MathLib::bigint value, ValueFlow::Value& true_value, ValueFlow::Value& false_value) { if (Token::Match(tok, "==|!=|>=|<=")) { setConditionalValue(true_value, tok, value); const char* greaterThan = ">="; const char* lessThan = "<="; if (lhs) std::swap(greaterThan, lessThan); if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) { setConditionalValue(false_value, tok, value - 1); } else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) { setConditionalValue(false_value, tok, value + 1); } else { setConditionalValue(false_value, tok, value); } } else { const char* greaterThan = ">"; const char* lessThan = "<"; if (lhs) std::swap(greaterThan, lessThan); if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) { setConditionalValue(true_value, tok, value + 1); setConditionalValue(false_value, tok, value); } else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) { setConditionalValue(true_value, tok, value - 1); setConditionalValue(false_value, tok, value); } } setValueBound(true_value, tok, lhs); setValueBound(false_value, tok, !lhs); } static bool isSaturated(MathLib::bigint value) { return value == std::numeric_limits::max() || value == std::numeric_limits::min(); } static void parseCompareEachInt( const Token* tok, const std::function& each, const std::function(const Token*)>& evaluate) { if (!tok->astOperand1() || !tok->astOperand2()) return; if (tok->isComparisonOp()) { std::vector value1 = evaluate(tok->astOperand1()); std::vector value2 = evaluate(tok->astOperand2()); if (!value1.empty() && !value2.empty()) { if (tok->astOperand1()->hasKnownIntValue()) value2.clear(); if (tok->astOperand2()->hasKnownIntValue()) value1.clear(); } for (const ValueFlow::Value& v1 : value1) { ValueFlow::Value true_value = v1; ValueFlow::Value false_value = v1; if (isSaturated(v1.intvalue) || astIsFloat(tok->astOperand2(), /*unknown*/ false)) continue; setConditionalValues(tok, true, v1.intvalue, true_value, false_value); each(tok->astOperand2(), std::move(true_value), std::move(false_value)); } for (const ValueFlow::Value& v2 : value2) { ValueFlow::Value true_value = v2; ValueFlow::Value false_value = v2; if (isSaturated(v2.intvalue) || astIsFloat(tok->astOperand1(), /*unknown*/ false)) continue; setConditionalValues(tok, false, v2.intvalue, true_value, false_value); each(tok->astOperand1(), std::move(true_value), std::move(false_value)); } } } static void parseCompareEachInt( const Token* tok, const std::function& each) { parseCompareEachInt(tok, each, [](const Token* t) -> std::vector { if (t->hasKnownIntValue()) return {t->values().front()}; std::vector result; std::copy_if(t->values().cbegin(), t->values().cend(), std::back_inserter(result), [&](const ValueFlow::Value& v) { if (v.path < 1) return false; if (!isNonConditionalPossibleIntValue(v)) return false; return true; }); return result; }); } const Token* ValueFlow::parseCompareInt(const Token* tok, ValueFlow::Value& true_value, ValueFlow::Value& false_value, const std::function(const Token*)>& evaluate) { const Token* result = nullptr; parseCompareEachInt( tok, [&](const Token* vartok, ValueFlow::Value true_value2, ValueFlow::Value false_value2) { if (result) return; result = vartok; true_value = std::move(true_value2); false_value = std::move(false_value2); }, [&](const Token* t) -> std::vector { std::vector r; std::vector v = evaluate(t); std::transform(v.cbegin(), v.cend(), std::back_inserter(r), [&](MathLib::bigint i) { return ValueFlow::Value{i}; }); return r; }); return result; } const Token *ValueFlow::parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value) { return parseCompareInt(tok, true_value, false_value, [](const Token* t) -> std::vector { if (t->hasKnownIntValue()) return {t->values().front().intvalue}; return std::vector{}; }); } static bool isEscapeScope(const Token* tok, const Settings* settings, bool unknown = false) { if (!Token::simpleMatch(tok, "{")) return false; // TODO this search for termTok in all subscopes. It should check the end of the scope. const Token * termTok = Token::findmatch(tok, "return|continue|break|throw|goto", tok->link()); if (termTok && termTok->scope() == tok->scope()) return true; std::string unknownFunction; if (settings->library.isScopeNoReturn(tok->link(), &unknownFunction)) return unknownFunction.empty() || unknown; return false; } static ValueFlow::Value castValue(ValueFlow::Value value, const ValueType::Sign sign, nonneg int bit) { if (value.isFloatValue()) { value.valueType = ValueFlow::Value::ValueType::INT; if (value.floatValue >= std::numeric_limits::min() && value.floatValue <= std::numeric_limits::max()) { value.intvalue = value.floatValue; } else { // don't perform UB value.intvalue = 0; } } if (bit < MathLib::bigint_bits) { const MathLib::biguint one = 1; value.intvalue &= (one << bit) - 1; if (sign == ValueType::Sign::SIGNED && value.intvalue & (one << (bit - 1))) { value.intvalue |= ~((one << bit) - 1ULL); } } return value; } static bool isNumeric(const ValueFlow::Value& value) { return value.isIntValue() || value.isFloatValue(); } void ValueFlow::combineValueProperties(const ValueFlow::Value &value1, const ValueFlow::Value &value2, ValueFlow::Value &result) { if (value1.isKnown() && value2.isKnown()) result.setKnown(); else if (value1.isImpossible() || value2.isImpossible()) result.setImpossible(); else if (value1.isInconclusive() || value2.isInconclusive()) result.setInconclusive(); else result.setPossible(); if (value1.tokvalue) result.tokvalue = value1.tokvalue; else if (value2.tokvalue) result.tokvalue = value2.tokvalue; if (value1.isSymbolicValue()) { result.valueType = value1.valueType; result.tokvalue = value1.tokvalue; } if (value2.isSymbolicValue()) { result.valueType = value2.valueType; result.tokvalue = value2.tokvalue; } if (value1.isIteratorValue()) result.valueType = value1.valueType; if (value2.isIteratorValue()) result.valueType = value2.valueType; result.condition = value1.condition ? value1.condition : value2.condition; result.varId = (value1.varId != 0) ? value1.varId : value2.varId; result.varvalue = (result.varId == value1.varId) ? value1.varvalue : value2.varvalue; result.errorPath = (value1.errorPath.empty() ? value2 : value1).errorPath; result.safe = value1.safe || value2.safe; if (value1.bound == ValueFlow::Value::Bound::Point || value2.bound == ValueFlow::Value::Bound::Point) { if (value1.bound == ValueFlow::Value::Bound::Upper || value2.bound == ValueFlow::Value::Bound::Upper) result.bound = ValueFlow::Value::Bound::Upper; if (value1.bound == ValueFlow::Value::Bound::Lower || value2.bound == ValueFlow::Value::Bound::Lower) result.bound = ValueFlow::Value::Bound::Lower; } if (value1.path != value2.path) result.path = -1; else result.path = value1.path; } static const Token *getCastTypeStartToken(const Token *parent, const Settings* settings) { // TODO: This might be a generic utility function? if (!Token::Match(parent, "{|(")) return nullptr; // Functional cast if (parent->isBinaryOp() && Token::Match(parent->astOperand1(), "%type% (|{") && parent->astOperand1()->tokType() == Token::eType && astIsPrimitive(parent)) return parent->astOperand1(); if (parent->str() != "(") return nullptr; if (!parent->astOperand2() && Token::Match(parent, "( %name%|::")) { const Token* ftok = parent->next(); if (ftok->isStandardType()) return ftok; if (Token::simpleMatch(ftok, "::")) ftok = ftok->next(); while (Token::Match(ftok, "%name% ::")) ftok = ftok->tokAt(2); if (settings->library.isNotLibraryFunction(ftok)) return parent->next(); } if (parent->astOperand2() && Token::Match(parent->astOperand1(), "const_cast|dynamic_cast|reinterpret_cast|static_cast <")) return parent->astOperand1()->tokAt(2); return nullptr; } // does the operation cause a loss of information? static bool isNonInvertibleOperation(const Token* tok) { return !Token::Match(tok, "+|-"); } static bool isComputableValue(const Token* parent, const ValueFlow::Value& value) { const bool noninvertible = isNonInvertibleOperation(parent); if (noninvertible && value.isImpossible()) return false; if (!value.isIntValue() && !value.isFloatValue() && !value.isTokValue() && !value.isIteratorValue()) return false; if (value.isIteratorValue() && !Token::Match(parent, "+|-")) return false; if (value.isTokValue() && (!parent->isComparisonOp() || !Token::Match(value.tokvalue, "{|%str%"))) return false; return true; } static Library::Container::Yield getContainerYield(Token* tok, const Settings* settings, Token** parent = nullptr) { if (Token::Match(tok, ". %name% (") && tok->astParent() == tok->tokAt(2) && tok->astOperand1() && tok->astOperand1()->valueType()) { const Library::Container* c = getLibraryContainer(tok->astOperand1()); if (parent) *parent = tok->astParent(); return c ? c->getYield(tok->strAt(1)) : Library::Container::Yield::NO_YIELD; } if (Token::Match(tok->previous(), "%name% (")) { if (parent) *parent = tok; if (const Library::Function* f = settings->library.getFunction(tok->previous())) { return f->containerYield; } } return Library::Container::Yield::NO_YIELD; } /** Set token value for cast */ static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings); static bool isCompatibleValueTypes(ValueFlow::Value::ValueType x, ValueFlow::Value::ValueType y) { static const std::unordered_map, EnumClassHash> compatibleTypes = { {ValueFlow::Value::ValueType::INT, {ValueFlow::Value::ValueType::FLOAT, ValueFlow::Value::ValueType::SYMBOLIC, ValueFlow::Value::ValueType::TOK}}, {ValueFlow::Value::ValueType::FLOAT, {ValueFlow::Value::ValueType::INT}}, {ValueFlow::Value::ValueType::TOK, {ValueFlow::Value::ValueType::INT}}, {ValueFlow::Value::ValueType::ITERATOR_START, {ValueFlow::Value::ValueType::INT}}, {ValueFlow::Value::ValueType::ITERATOR_END, {ValueFlow::Value::ValueType::INT}}, }; if (x == y) return true; auto it = compatibleTypes.find(x); if (it == compatibleTypes.end()) return false; return it->second.count(y) > 0; } static bool isCompatibleValues(const ValueFlow::Value& value1, const ValueFlow::Value& value2) { if (value1.isSymbolicValue() && value2.isSymbolicValue() && value1.tokvalue->exprId() != value2.tokvalue->exprId()) return false; if (!isCompatibleValueTypes(value1.valueType, value2.valueType)) return false; if (value1.isKnown() || value2.isKnown()) return true; if (value1.isImpossible() || value2.isImpossible()) return false; if (value1.varId == 0 || value2.varId == 0) return true; if (value1.varId == value2.varId && value1.varvalue == value2.varvalue && value1.isIntValue() && value2.isIntValue()) return true; return false; } static ValueFlow::Value truncateImplicitConversion(Token* parent, const ValueFlow::Value& value, const Settings* settings) { if (!value.isIntValue() && !value.isFloatValue()) return value; if (!parent) return value; if (!parent->isBinaryOp()) return value; if (!parent->isConstOp()) return value; if (!astIsIntegral(parent->astOperand1(), false)) return value; if (!astIsIntegral(parent->astOperand2(), false)) return value; const ValueType* vt1 = parent->astOperand1()->valueType(); const ValueType* vt2 = parent->astOperand2()->valueType(); // If the sign is the same there is no truncation if (vt1->sign == vt2->sign) return value; const size_t n1 = ValueFlow::getSizeOf(*vt1, settings); const size_t n2 = ValueFlow::getSizeOf(*vt2, settings); ValueType::Sign sign = ValueType::Sign::UNSIGNED; if (n1 < n2) sign = vt2->sign; else if (n1 > n2) sign = vt1->sign; ValueFlow::Value v = castValue(value, sign, std::max(n1, n2) * 8); v.wideintvalue = value.intvalue; return v; } /** set ValueFlow value and perform calculations if possible */ static void setTokenValue(Token* tok, ValueFlow::Value value, const Settings* settings, SourceLocation loc = SourceLocation::current()) { // Skip setting values that are too big since its ambiguous if (!value.isImpossible() && value.isIntValue() && value.intvalue < 0 && astIsUnsigned(tok) && ValueFlow::getSizeOf(*tok->valueType(), settings) >= sizeof(MathLib::bigint)) return; if (!value.isImpossible() && value.isIntValue()) value = truncateImplicitConversion(tok->astParent(), value, settings); if (settings->debugnormal) setSourceLocation(value, loc, tok); if (!tok->addValue(value)) return; if (value.path < 0) return; Token *parent = tok->astParent(); if (!parent) return; if (Token::simpleMatch(parent, ",") && !parent->isInitComma() && astIsRHS(tok)) { const Token* callParent = findParent(parent, [](const Token* p) { return !Token::simpleMatch(p, ","); }); // Ensure that the comma isn't a function call if (!callParent || (!Token::Match(callParent->previous(), "%name%|> (") && !Token::simpleMatch(callParent, "{") && (!Token::Match(callParent, "( %name%") || settings->library.isNotLibraryFunction(callParent->next())) && !(callParent->str() == "(" && (Token::simpleMatch(callParent->astOperand1(), "*") || Token::Match(callParent->astOperand1(), "%name%|("))))) { setTokenValue(parent, std::move(value), settings); return; } } if (Token::simpleMatch(parent, "=") && astIsRHS(tok)) { setTokenValue(parent, value, settings); if (!value.isUninitValue()) return; } if (value.isContainerSizeValue() && astIsContainer(tok)) { // .empty, .size, +"abc", +'a' if (Token::Match(parent, "+|==|!=") && parent->astOperand1() && parent->astOperand2()) { for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) { if (value1.isImpossible()) continue; for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) { if (value2.isImpossible()) continue; if (value1.path != value2.path) continue; ValueFlow::Value result; if (Token::Match(parent, "%comp%")) result.valueType = ValueFlow::Value::ValueType::INT; else result.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; if (value1.isContainerSizeValue() && value2.isContainerSizeValue()) result.intvalue = calculate(parent->str(), value1.intvalue, value2.intvalue); else if (value1.isContainerSizeValue() && value2.isTokValue() && value2.tokvalue->tokType() == Token::eString) result.intvalue = calculate(parent->str(), value1.intvalue, MathLib::bigint(Token::getStrLength(value2.tokvalue))); else if (value2.isContainerSizeValue() && value1.isTokValue() && value1.tokvalue->tokType() == Token::eString) result.intvalue = calculate(parent->str(), MathLib::bigint(Token::getStrLength(value1.tokvalue)), value2.intvalue); else continue; combineValueProperties(value1, value2, result); if (Token::simpleMatch(parent, "==") && result.intvalue) continue; if (Token::simpleMatch(parent, "!=") && !result.intvalue) continue; setTokenValue(parent, std::move(result), settings); } } } Token* next = nullptr; const Library::Container::Yield yields = getContainerYield(parent, settings, &next); if (yields == Library::Container::Yield::SIZE) { ValueFlow::Value v(value); v.valueType = ValueFlow::Value::ValueType::INT; setTokenValue(next, std::move(v), settings); } else if (yields == Library::Container::Yield::EMPTY) { ValueFlow::Value v(value); v.valueType = ValueFlow::Value::ValueType::INT; v.bound = ValueFlow::Value::Bound::Point; if (value.isImpossible()) { if (value.intvalue == 0) v.setKnown(); else if ((value.bound == ValueFlow::Value::Bound::Upper && value.intvalue > 0) || (value.bound == ValueFlow::Value::Bound::Lower && value.intvalue < 0)) { v.intvalue = 0; v.setKnown(); } else v.setPossible(); } else { v.intvalue = !v.intvalue; } setTokenValue(next, std::move(v), settings); } return; } if (value.isLifetimeValue()) { if (!ValueFlow::isLifetimeBorrowed(parent, settings)) return; if (value.lifetimeKind == ValueFlow::Value::LifetimeKind::Iterator && astIsIterator(parent)) { setTokenValue(parent,std::move(value),settings); } else if (astIsPointer(tok) && astIsPointer(parent) && !parent->isUnaryOp("*") && (parent->isArithmeticalOp() || parent->isCast())) { setTokenValue(parent,std::move(value),settings); } return; } if (value.isUninitValue()) { if (Token::Match(tok, ". %var%")) setTokenValue(tok->next(), value, settings); if (parent->isCast()) { setTokenValue(parent, std::move(value), settings); return; } ValueFlow::Value pvalue = value; if (!value.subexpressions.empty() && Token::Match(parent, ". %var%")) { if (contains(value.subexpressions, parent->next()->str())) pvalue.subexpressions.clear(); else return; } if (parent->isUnaryOp("&")) { pvalue.indirect++; setTokenValue(parent, std::move(pvalue), settings); } else if (Token::Match(parent, ". %var%") && parent->astOperand1() == tok && parent->astOperand2()) { if (parent->originalName() == "->" && pvalue.indirect > 0) pvalue.indirect--; setTokenValue(parent->astOperand2(), std::move(pvalue), settings); } else if (Token::Match(parent->astParent(), ". %var%") && parent->astParent()->astOperand1() == parent) { if (parent->astParent()->originalName() == "->" && pvalue.indirect > 0) pvalue.indirect--; setTokenValue(parent->astParent()->astOperand2(), std::move(pvalue), settings); } else if (parent->isUnaryOp("*") && pvalue.indirect > 0) { pvalue.indirect--; setTokenValue(parent, std::move(pvalue), settings); } return; } // cast.. if (const Token *castType = getCastTypeStartToken(parent, settings)) { if (contains({ValueFlow::Value::ValueType::INT, ValueFlow::Value::ValueType::SYMBOLIC}, value.valueType) && Token::simpleMatch(parent->astOperand1(), "dynamic_cast")) return; const ValueType &valueType = ValueType::parseDecl(castType, *settings); if (value.isImpossible() && value.isIntValue() && value.intvalue < 0 && astIsUnsigned(tok) && valueType.sign == ValueType::SIGNED && tok->valueType() && ValueFlow::getSizeOf(*tok->valueType(), settings) >= ValueFlow::getSizeOf(valueType, settings)) return; setTokenValueCast(parent, valueType, value, settings); } else if (parent->str() == ":") { setTokenValue(parent,value,settings); } else if (parent->str() == "?" && tok->str() == ":" && tok == parent->astOperand2() && parent->astOperand1()) { // is condition always true/false? if (parent->astOperand1()->hasKnownValue()) { const ValueFlow::Value &condvalue = parent->astOperand1()->values().front(); const bool cond(condvalue.isTokValue() || (condvalue.isIntValue() && condvalue.intvalue != 0)); if (cond && !tok->astOperand1()) { // true condition, no second operator setTokenValue(parent, condvalue, settings); } else { const Token *op = cond ? tok->astOperand1() : tok->astOperand2(); if (!op) // #7769 segmentation fault at setTokenValue() return; const std::list &values = op->values(); if (std::find(values.cbegin(), values.cend(), value) != values.cend()) setTokenValue(parent, value, settings); } } else if (!value.isImpossible()) { // is condition only depending on 1 variable? // cppcheck-suppress[variableScope] #8541 nonneg int varId = 0; bool ret = false; visitAstNodes(parent->astOperand1(), [&](const Token *t) { if (t->varId()) { if (varId > 0 || value.varId != 0) ret = true; varId = t->varId(); } else if (t->str() == "(" && Token::Match(t->previous(), "%name%")) ret = true; // function call return ret ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2; }); if (ret) return; ValueFlow::Value v(value); v.conditional = true; v.changeKnownToPossible(); setTokenValue(parent, v, settings); } } else if (parent->str() == "?" && value.isIntValue() && tok == parent->astOperand1() && value.isKnown() && parent->astOperand2() && parent->astOperand2()->astOperand1() && parent->astOperand2()->astOperand2()) { const std::list &values = (value.intvalue == 0 ? parent->astOperand2()->astOperand2()->values() : parent->astOperand2()->astOperand1()->values()); for (const ValueFlow::Value &v : values) setTokenValue(parent, v, settings); } // Calculations.. else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp) || (parent->tokType() == Token::eLogicalOp)) && parent->astOperand1() && parent->astOperand2()) { const bool noninvertible = isNonInvertibleOperation(parent); // Skip operators with impossible values that are not invertible if (noninvertible && value.isImpossible()) return; // known result when a operand is 0. if (Token::Match(parent, "[&*]") && astIsIntegral(parent, true) && value.isKnown() && value.isIntValue() && value.intvalue == 0) { setTokenValue(parent, std::move(value), settings); return; } // known result when a operand is true. if (Token::simpleMatch(parent, "&&") && value.isKnown() && value.isIntValue() && value.intvalue==0) { setTokenValue(parent, std::move(value), settings); return; } // known result when a operand is false. if (Token::simpleMatch(parent, "||") && value.isKnown() && value.isIntValue() && value.intvalue!=0) { setTokenValue(parent, std::move(value), settings); return; } for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) { if (!isComputableValue(parent, value1)) continue; for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) { if (value1.path != value2.path) continue; if (!isComputableValue(parent, value2)) continue; if (value1.isIteratorValue() && value2.isIteratorValue()) continue; if (!isCompatibleValues(value1, value2)) continue; ValueFlow::Value result(0); combineValueProperties(value1, value2, result); if (astIsFloat(parent, false)) { if (!result.isIntValue() && !result.isFloatValue()) continue; result.valueType = ValueFlow::Value::ValueType::FLOAT; } const double floatValue1 = value1.isFloatValue() ? value1.floatValue : value1.intvalue; const double floatValue2 = value2.isFloatValue() ? value2.floatValue : value2.intvalue; const auto intValue1 = [&]() -> MathLib::bigint { return value1.isFloatValue() ? static_cast(value1.floatValue) : value1.intvalue; }; const auto intValue2 = [&]() -> MathLib::bigint { return value2.isFloatValue() ? static_cast(value2.floatValue) : value2.intvalue; }; if ((value1.isFloatValue() || value2.isFloatValue()) && Token::Match(parent, "&|^|%|<<|>>|==|!=|%or%")) continue; if (Token::Match(parent, "==|!=")) { if ((value1.isIntValue() && value2.isTokValue()) || (value1.isTokValue() && value2.isIntValue())) { if (parent->str() == "==") result.intvalue = 0; else if (parent->str() == "!=") result.intvalue = 1; } else if (value1.isIntValue() && value2.isIntValue()) { bool error = false; result.intvalue = calculate(parent->str(), intValue1(), intValue2(), &error); if (error) continue; } else if (value1.isTokValue() && value2.isTokValue() && (astIsContainer(parent->astOperand1()) || astIsContainer(parent->astOperand2()))) { const Token* tok1 = value1.tokvalue; const Token* tok2 = value2.tokvalue; bool equal = false; if (Token::Match(tok1, "%str%") && Token::Match(tok2, "%str%")) { equal = tok1->str() == tok2->str(); } else if (Token::simpleMatch(tok1, "{") && Token::simpleMatch(tok2, "{")) { std::vector args1 = getArguments(tok1); std::vector args2 = getArguments(tok2); if (args1.size() == args2.size()) { if (!std::all_of(args1.begin(), args1.end(), std::mem_fn(&Token::hasKnownIntValue))) continue; if (!std::all_of(args2.begin(), args2.end(), std::mem_fn(&Token::hasKnownIntValue))) continue; equal = std::equal(args1.begin(), args1.end(), args2.begin(), [&](const Token* atok, const Token* btok) { return atok->values().front().intvalue == btok->values().front().intvalue; }); } else { equal = false; } } else { continue; } result.intvalue = parent->str() == "==" ? equal : !equal; } else { continue; } setTokenValue(parent, result, settings); } else if (Token::Match(parent, "%op%")) { if (Token::Match(parent, "%comp%")) { if (!result.isFloatValue() && !value1.isIntValue() && !value2.isIntValue()) continue; } else { if (value1.isTokValue() || value2.isTokValue()) break; } bool error = false; if (result.isFloatValue()) { result.floatValue = calculate(parent->str(), floatValue1, floatValue2, &error); } else { result.intvalue = calculate(parent->str(), intValue1(), intValue2(), &error); } if (error) continue; // If the bound comes from the second value then invert the bound when subtracting if (Token::simpleMatch(parent, "-") && value2.bound == result.bound && value2.bound != ValueFlow::Value::Bound::Point) result.invertBound(); setTokenValue(parent, result, settings); } } } } // ! else if (parent->str() == "!") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue()) continue; if (val.isImpossible() && val.intvalue != 0) continue; ValueFlow::Value v(val); if (val.isImpossible()) v.setKnown(); else v.intvalue = !v.intvalue; setTokenValue(parent, std::move(v), settings); } } // ~ else if (parent->str() == "~") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue()) continue; ValueFlow::Value v(val); v.intvalue = ~v.intvalue; int bits = 0; if (tok->valueType() && tok->valueType()->sign == ValueType::Sign::UNSIGNED && tok->valueType()->pointer == 0) { if (tok->valueType()->type == ValueType::Type::INT) bits = settings->platform.int_bit; else if (tok->valueType()->type == ValueType::Type::LONG) bits = settings->platform.long_bit; } if (bits > 0 && bits < MathLib::bigint_bits) v.intvalue &= (((MathLib::biguint)1)<isUnaryOp("-")) { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue() && !val.isFloatValue()) continue; ValueFlow::Value v(val); if (v.isIntValue()) { if (v.intvalue == LLONG_MIN) // Value can't be inverted continue; v.intvalue = -v.intvalue; } else v.floatValue = -v.floatValue; v.invertBound(); setTokenValue(parent, std::move(v), settings); } } // increment else if (parent->str() == "++") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue() && !val.isFloatValue() && !val.isSymbolicValue()) continue; ValueFlow::Value v(val); if (parent == tok->previous()) { if (v.isIntValue() || v.isSymbolicValue()) v.intvalue = v.intvalue + 1; else v.floatValue = v.floatValue + 1.0; } setTokenValue(parent, std::move(v), settings); } } // decrement else if (parent->str() == "--") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue() && !val.isFloatValue() && !val.isSymbolicValue()) continue; ValueFlow::Value v(val); if (parent == tok->previous()) { if (v.isIntValue() || v.isSymbolicValue()) v.intvalue = v.intvalue - 1; else v.floatValue = v.floatValue - 1.0; } setTokenValue(parent, std::move(v), settings); } } else if (Token::Match(parent, ":: %name%") && parent->astOperand2() == tok) { setTokenValue(parent, value, settings); } // Calling std::size or std::empty on an array else if (value.isTokValue() && Token::simpleMatch(value.tokvalue, "{") && tok->variable() && tok->variable()->isArray() && Token::Match(parent->previous(), "%name% (") && astIsRHS(tok)) { std::vector args = getArguments(value.tokvalue); if (const Library::Function* f = settings->library.getFunction(parent->previous())) { if (f->containerYield == Library::Container::Yield::SIZE) { ValueFlow::Value v(value); v.valueType = ValueFlow::Value::ValueType::INT; v.intvalue = args.size(); setTokenValue(parent, std::move(v), settings); } else if (f->containerYield == Library::Container::Yield::EMPTY) { ValueFlow::Value v(value); v.intvalue = args.empty(); v.valueType = ValueFlow::Value::ValueType::INT; setTokenValue(parent, std::move(v), settings); } } } } static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings) { if (valueType.pointer || value.isImpossible()) setTokenValue(parent,value,settings); else if (valueType.type == ValueType::Type::CHAR) setTokenValue(parent, castValue(value, valueType.sign, settings->platform.char_bit), settings); else if (valueType.type == ValueType::Type::SHORT) setTokenValue(parent, castValue(value, valueType.sign, settings->platform.short_bit), settings); else if (valueType.type == ValueType::Type::INT) setTokenValue(parent, castValue(value, valueType.sign, settings->platform.int_bit), settings); else if (valueType.type == ValueType::Type::LONG) setTokenValue(parent, castValue(value, valueType.sign, settings->platform.long_bit), settings); else if (valueType.type == ValueType::Type::LONGLONG) setTokenValue(parent, castValue(value, valueType.sign, settings->platform.long_long_bit), settings); else if (valueType.isFloat() && isNumeric(value)) { ValueFlow::Value floatValue = value; floatValue.valueType = ValueFlow::Value::ValueType::FLOAT; if (value.isIntValue()) floatValue.floatValue = value.intvalue; setTokenValue(parent, std::move(floatValue), settings); } else if (value.isIntValue()) { const long long charMax = settings->platform.signedCharMax(); const long long charMin = settings->platform.signedCharMin(); if (charMin <= value.intvalue && value.intvalue <= charMax) { // unknown type, but value is small so there should be no truncation etc setTokenValue(parent,value,settings); } } } static nonneg int getSizeOfType(const Token *typeTok, const Settings *settings) { const ValueType &valueType = ValueType::parseDecl(typeTok, *settings); return ValueFlow::getSizeOf(valueType, settings); } size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings *settings) { if (vt.pointer) return settings->platform.sizeof_pointer; if (vt.type == ValueType::Type::BOOL || vt.type == ValueType::Type::CHAR) return 1; if (vt.type == ValueType::Type::SHORT) return settings->platform.sizeof_short; if (vt.type == ValueType::Type::WCHAR_T) return settings->platform.sizeof_wchar_t; if (vt.type == ValueType::Type::INT) return settings->platform.sizeof_int; if (vt.type == ValueType::Type::LONG) return settings->platform.sizeof_long; if (vt.type == ValueType::Type::LONGLONG) return settings->platform.sizeof_long_long; if (vt.type == ValueType::Type::FLOAT) return settings->platform.sizeof_float; if (vt.type == ValueType::Type::DOUBLE) return settings->platform.sizeof_double; if (vt.type == ValueType::Type::LONGDOUBLE) return settings->platform.sizeof_long_double; return 0; } static bool getMinMaxValues(const ValueType* vt, const Platform& platform, MathLib::bigint& minValue, MathLib::bigint& maxValue); // Handle various constants.. static Token * valueFlowSetConstantValue(Token *tok, const Settings *settings, bool cpp) { if ((tok->isNumber() && MathLib::isInt(tok->str())) || (tok->tokType() == Token::eChar)) { try { MathLib::bigint signedValue = MathLib::toBigNumber(tok->str()); const ValueType* vt = tok->valueType(); if (vt && vt->sign == ValueType::UNSIGNED && signedValue < 0 && ValueFlow::getSizeOf(*vt, settings) < sizeof(MathLib::bigint)) { MathLib::bigint minValue{}, maxValue{}; if (getMinMaxValues(tok->valueType(), settings->platform, minValue, maxValue)) signedValue += maxValue + 1; } ValueFlow::Value value(signedValue); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, std::move(value), settings); } catch (const std::exception & /*e*/) { // Bad character literal } } else if (tok->isNumber() && MathLib::isFloat(tok->str())) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::FLOAT; value.floatValue = MathLib::toDoubleNumber(tok->str()); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, std::move(value), settings); } else if (tok->enumerator() && tok->enumerator()->value_known) { ValueFlow::Value value(tok->enumerator()->value); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, std::move(value), settings); } else if (tok->str() == "NULL" || (cpp && tok->str() == "nullptr")) { ValueFlow::Value value(0); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, std::move(value), settings); } else if (Token::simpleMatch(tok, "sizeof (")) { if (tok->next()->astOperand2() && !tok->next()->astOperand2()->isLiteral() && tok->next()->astOperand2()->valueType() && (tok->next()->astOperand2()->valueType()->pointer == 0 || // <- TODO this is a bailout, abort when there are array->pointer conversions (tok->next()->astOperand2()->variable() && !tok->next()->astOperand2()->variable()->isArray())) && !tok->next()->astOperand2()->valueType()->isEnum()) { // <- TODO this is a bailout, handle enum with non-int types const size_t sz = ValueFlow::getSizeOf(*tok->next()->astOperand2()->valueType(), settings); if (sz) { ValueFlow::Value value(sz); value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); return tok->linkAt(1); } } const Token *tok2 = tok->tokAt(2); // skip over tokens to find variable or type while (tok2 && !tok2->isStandardType() && Token::Match(tok2, "%name% ::|.|[")) { if (tok2->next()->str() == "[") tok2 = tok2->linkAt(1)->next(); else tok2 = tok2->tokAt(2); } if (Token::simpleMatch(tok, "sizeof ( *")) { const ValueType *vt = tok->tokAt(2)->valueType(); const size_t sz = vt ? ValueFlow::getSizeOf(*vt, settings) : 0; if (sz > 0) { ValueFlow::Value value(sz); if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified) value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); } } else if (tok2->enumerator() && tok2->enumerator()->scope) { long long size = settings->platform.sizeof_int; const Token * type = tok2->enumerator()->scope->enumType; if (type) { size = getSizeOfType(type, settings); if (size == 0) tok->linkAt(1); } ValueFlow::Value value(size); if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified) value.setKnown(); setTokenValue(tok, value, settings); setTokenValue(tok->next(), std::move(value), settings); } else if (tok2->type() && tok2->type()->isEnumType()) { long long size = settings->platform.sizeof_int; if (tok2->type()->classScope) { const Token * type = tok2->type()->classScope->enumType; if (type) { size = getSizeOfType(type, settings); } } ValueFlow::Value value(size); if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified) value.setKnown(); setTokenValue(tok, value, settings); setTokenValue(tok->next(), std::move(value), settings); } else if (Token::Match(tok, "sizeof ( %var% ) /") && tok->next()->astParent() == tok->tokAt(4) && tok->tokAt(4)->astOperand2() && Token::simpleMatch(tok->tokAt(4)->astOperand2()->previous(), "sizeof (")) { // Get number of elements in array const Token *sz1 = tok->tokAt(2); const Token *sz2 = tok->tokAt(4)->astOperand2(); // left parenthesis of sizeof on rhs const nonneg int varid1 = sz1->varId(); if (varid1 && sz1->variable() && sz1->variable()->isArray() && !sz1->variable()->dimensions().empty() && sz1->variable()->dimensionKnown(0) && Token::Match(sz2->astOperand2(), "*|[") && Token::Match(sz2->astOperand2()->astOperand1(), "%varid%", varid1)) { ValueFlow::Value value(sz1->variable()->dimension(0)); if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified) value.setKnown(); setTokenValue(tok->tokAt(4), std::move(value), settings); } } else if (Token::Match(tok2, "%var% )")) { const Variable *var = tok2->variable(); // only look for single token types (no pointers or references yet) if (var && var->typeStartToken() == var->typeEndToken()) { // find the size of the type size_t size = 0; if (var->isEnumType()) { size = settings->platform.sizeof_int; if (var->type()->classScope && var->type()->classScope->enumType) size = getSizeOfType(var->type()->classScope->enumType, settings); } else if (var->valueType()) { size = ValueFlow::getSizeOf(*var->valueType(), settings); } else if (!var->type()) { size = getSizeOfType(var->typeStartToken(), settings); } // find the number of elements size_t count = 1; for (size_t i = 0; i < var->dimensions().size(); ++i) { if (var->dimensionKnown(i)) count *= var->dimension(i); else count = 0; } if (size && count > 0) { ValueFlow::Value value(count * size); if (settings->platform.type != Platform::Type::Unspecified) value.setKnown(); setTokenValue(tok, value, settings); setTokenValue(tok->next(), std::move(value), settings); } } } else if (tok2->tokType() == Token::eString) { const size_t sz = Token::getStrSize(tok2, settings); if (sz > 0) { ValueFlow::Value value(sz); value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); } } else if (tok2->tokType() == Token::eChar) { nonneg int sz = 0; if (cpp && settings->standards.cpp >= Standards::CPP20 && tok2->isUtf8()) sz = 1; else if (tok2->isUtf16()) sz = 2; else if (tok2->isUtf32()) sz = 4; else if (tok2->isLong()) sz = settings->platform.sizeof_wchar_t; else if ((tok2->isCChar() && !cpp) || (tok2->isCMultiChar())) sz = settings->platform.sizeof_int; else sz = 1; if (sz > 0) { ValueFlow::Value value(sz); value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); } } else if (!tok2->type()) { const ValueType& vt = ValueType::parseDecl(tok2, *settings); size_t sz = ValueFlow::getSizeOf(vt, settings); const Token* brac = tok2->astParent(); while (Token::simpleMatch(brac, "[")) { const Token* num = brac->astOperand2(); if (num && ((num->isNumber() && MathLib::isInt(num->str())) || num->tokType() == Token::eChar)) { try { const MathLib::biguint dim = MathLib::toBigUNumber(num->str()); sz *= dim; brac = brac->astParent(); continue; } catch (const std::exception& /*e*/) { // Bad integer literal } } sz = 0; break; } if (sz > 0) { ValueFlow::Value value(sz); if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified) value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); } } // skip over enum tok = tok->linkAt(1); } else if (Token::Match(tok, "%name% [{(] [)}]") && (tok->isStandardType() || (tok->variable() && tok->variable()->nameToken() == tok && (tok->variable()->isPointer() || (tok->variable()->valueType() && tok->variable()->valueType()->isIntegral()))))) { ValueFlow::Value value(0); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); } else if (Token::Match(tok, "%name% = {") && tok->variable() && (tok->variable()->isPointer() || (tok->variable()->valueType() && tok->variable()->valueType()->isIntegral()))) { if (Token::simpleMatch(tok->tokAt(3), "}")) { ValueFlow::Value value(0); value.setKnown(); setTokenValue(tok->tokAt(2), std::move(value), settings); } else if (tok->tokAt(2)->astOperand1() && tok->tokAt(2)->astOperand1()->hasKnownIntValue()) { ValueFlow::Value value(tok->tokAt(2)->astOperand1()->getKnownIntValue()); value.setKnown(); setTokenValue(tok->tokAt(2), std::move(value), settings); } } return tok->next(); } static void valueFlowNumber(TokenList &tokenlist, const Settings* settings) { for (Token *tok = tokenlist.front(); tok;) { tok = valueFlowSetConstantValue(tok, settings, tokenlist.isCPP()); } if (tokenlist.isCPP()) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->isName() && !tok->varId() && Token::Match(tok, "false|true")) { ValueFlow::Value value(tok->str() == "true"); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, std::move(value), settings); } else if (Token::Match(tok, "[(,] NULL [,)]")) { // NULL function parameters are not simplified in the // normal tokenlist ValueFlow::Value value(0); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok->next(), std::move(value), settings); } } } } static void valueFlowString(TokenList &tokenlist, const Settings* settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->tokType() == Token::eString) { ValueFlow::Value strvalue; strvalue.valueType = ValueFlow::Value::ValueType::TOK; strvalue.tokvalue = tok; strvalue.setKnown(); setTokenValue(tok, std::move(strvalue), settings); } } } static void valueFlowArray(TokenList &tokenlist, const Settings *settings) { std::map constantArrays; for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->varId() > 0) { // array const std::map::const_iterator it = constantArrays.find(tok->varId()); if (it != constantArrays.end()) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::TOK; value.tokvalue = it->second; value.setKnown(); setTokenValue(tok, std::move(value), settings); } // const array decl else if (tok->variable() && tok->variable()->isArray() && tok->variable()->isConst() && tok->variable()->nameToken() == tok && Token::Match(tok, "%var% [ %num%| ] = {")) { Token* rhstok = tok->next()->link()->tokAt(2); constantArrays[tok->varId()] = rhstok; tok = rhstok->link(); } // pointer = array else if (tok->variable() && tok->variable()->isArray() && Token::simpleMatch(tok->astParent(), "=") && astIsRHS(tok) && tok->astParent()->astOperand1() && tok->astParent()->astOperand1()->variable() && tok->astParent()->astOperand1()->variable()->isPointer()) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::TOK; value.tokvalue = tok; value.setKnown(); setTokenValue(tok, std::move(value), settings); } continue; } if (Token::Match(tok, "const %type% %var% [ %num%| ] = {")) { Token *vartok = tok->tokAt(2); Token *rhstok = vartok->next()->link()->tokAt(2); constantArrays[vartok->varId()] = rhstok; tok = rhstok->link(); continue; } if (Token::Match(tok, "const char %var% [ %num%| ] = %str% ;")) { Token *vartok = tok->tokAt(2); Token *strtok = vartok->next()->link()->tokAt(2); constantArrays[vartok->varId()] = strtok; tok = strtok->next(); continue; } } } static bool isNonZero(const Token *tok) { return tok && (!tok->hasKnownIntValue() || tok->values().front().intvalue != 0); } static const Token *getOtherOperand(const Token *tok) { if (!tok) return nullptr; if (!tok->astParent()) return nullptr; if (tok->astParent()->astOperand1() != tok) return tok->astParent()->astOperand1(); if (tok->astParent()->astOperand2() != tok) return tok->astParent()->astOperand2(); return nullptr; } static void valueFlowArrayBool(TokenList &tokenlist, const Settings *settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; const Variable *var = nullptr; bool known = false; const std::list::const_iterator val = std::find_if(tok->values().cbegin(), tok->values().cend(), std::mem_fn(&ValueFlow::Value::isTokValue)); if (val == tok->values().end()) { var = tok->variable(); known = true; } else { var = val->tokvalue->variable(); known = val->isKnown(); } if (!var) continue; if (!var->isArray() || var->isArgument() || var->isStlType()) continue; if (isNonZero(getOtherOperand(tok)) && Token::Match(tok->astParent(), "%comp%")) continue; // TODO: Check for function argument if ((astIsBool(tok->astParent()) && !Token::Match(tok->astParent(), "(|%name%")) || (tok->astParent() && Token::Match(tok->astParent()->previous(), "if|while|for ("))) { ValueFlow::Value value{1}; if (known) value.setKnown(); setTokenValue(tok, std::move(value), settings); } } } static void valueFlowArrayElement(TokenList& tokenlist, const Settings* settings) { for (Token* tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; const Token* indexTok = nullptr; const Token* arrayTok = nullptr; if (Token::simpleMatch(tok, "[") && tok->isBinaryOp()) { indexTok = tok->astOperand2(); arrayTok = tok->astOperand1(); } else if (Token::Match(tok->tokAt(-2), ". %name% (") && astIsContainer(tok->tokAt(-2)->astOperand1())) { arrayTok = tok->tokAt(-2)->astOperand1(); const Library::Container* container = getLibraryContainer(arrayTok); if (!container || container->stdAssociativeLike) continue; const Library::Container::Yield yield = container->getYield(tok->strAt(-1)); if (yield != Library::Container::Yield::AT_INDEX) continue; indexTok = tok->astOperand2(); } if (!indexTok || !arrayTok) continue; for (const ValueFlow::Value& arrayValue : arrayTok->values()) { if (!arrayValue.isTokValue()) continue; if (arrayValue.isImpossible()) continue; for (const ValueFlow::Value& indexValue : indexTok->values()) { if (!indexValue.isIntValue()) continue; if (indexValue.isImpossible()) continue; if (!arrayValue.isKnown() && !indexValue.isKnown() && arrayValue.varId != 0 && indexValue.varId != 0 && !(arrayValue.varId == indexValue.varId && arrayValue.varvalue == indexValue.varvalue)) continue; ValueFlow::Value result(0); result.condition = arrayValue.condition ? arrayValue.condition : indexValue.condition; result.setInconclusive(arrayValue.isInconclusive() || indexValue.isInconclusive()); result.varId = (arrayValue.varId != 0) ? arrayValue.varId : indexValue.varId; result.varvalue = (result.varId == arrayValue.varId) ? arrayValue.intvalue : indexValue.intvalue; if (arrayValue.valueKind == indexValue.valueKind) result.valueKind = arrayValue.valueKind; result.errorPath.insert(result.errorPath.end(), arrayValue.errorPath.cbegin(), arrayValue.errorPath.cend()); result.errorPath.insert(result.errorPath.end(), indexValue.errorPath.cbegin(), indexValue.errorPath.cend()); const MathLib::bigint index = indexValue.intvalue; if (arrayValue.tokvalue->tokType() == Token::eString) { const std::string s = arrayValue.tokvalue->strValue(); if (index == s.size()) { result.intvalue = 0; setTokenValue(tok, result, settings); } else if (index >= 0 && index < s.size()) { result.intvalue = s[index]; setTokenValue(tok, result, settings); } } else if (Token::simpleMatch(arrayValue.tokvalue, "{")) { std::vector args = getArguments(arrayValue.tokvalue); if (index < 0 || index >= args.size()) continue; const Token* arg = args[index]; if (!arg->hasKnownIntValue()) continue; const ValueFlow::Value& v = arg->values().front(); result.intvalue = v.intvalue; result.errorPath.insert(result.errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend()); setTokenValue(tok, result, settings); } } } } } static void valueFlowPointerAlias(TokenList &tokenlist, const Settings* settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { // not address of if (!tok->isUnaryOp("&")) continue; // parent should be a '=' if (!Token::simpleMatch(tok->astParent(), "=")) continue; // child should be some buffer or variable const Token *vartok = tok->astOperand1(); while (vartok) { if (vartok->str() == "[") vartok = vartok->astOperand1(); else if (vartok->str() == "." || vartok->str() == "::") vartok = vartok->astOperand2(); else break; } if (!(vartok && vartok->variable() && !vartok->variable()->isPointer())) continue; ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::TOK; value.tokvalue = tok; setTokenValue(tok, std::move(value), settings); } } static void valueFlowBitAnd(TokenList &tokenlist, const Settings* settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->str() != "&") continue; if (tok->hasKnownValue()) continue; if (!tok->astOperand1() || !tok->astOperand2()) continue; MathLib::bigint number; if (MathLib::isInt(tok->astOperand1()->str())) number = MathLib::toBigNumber(tok->astOperand1()->str()); else if (MathLib::isInt(tok->astOperand2()->str())) number = MathLib::toBigNumber(tok->astOperand2()->str()); else continue; int bit = 0; while (bit <= (MathLib::bigint_bits - 2) && ((((MathLib::bigint)1) << bit) < number)) ++bit; if ((((MathLib::bigint)1) << bit) == number) { setTokenValue(tok, ValueFlow::Value(0), settings); setTokenValue(tok, ValueFlow::Value(number), settings); } } } static void valueFlowSameExpressions(TokenList &tokenlist, const Settings* settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; if (!tok->astOperand1() || !tok->astOperand2()) continue; if (tok->astOperand1()->isLiteral() || tok->astOperand2()->isLiteral()) continue; if (!astIsIntegral(tok->astOperand1(), false) && !astIsIntegral(tok->astOperand2(), false)) continue; ValueFlow::Value val; if (Token::Match(tok, "==|>=|<=|/")) { val = ValueFlow::Value(1); val.setKnown(); } if (Token::Match(tok, "!=|>|<|%|-")) { val = ValueFlow::Value(0); val.setKnown(); } if (!val.isKnown()) continue; if (isSameExpression(tokenlist.isCPP(), false, tok->astOperand1(), tok->astOperand2(), settings->library, true, true, &val.errorPath)) { setTokenValue(tok, std::move(val), settings); } } } static bool getExpressionRange(const Token *expr, MathLib::bigint *minvalue, MathLib::bigint *maxvalue) { if (expr->hasKnownIntValue()) { if (minvalue) *minvalue = expr->values().front().intvalue; if (maxvalue) *maxvalue = expr->values().front().intvalue; return true; } if (expr->str() == "&" && expr->astOperand1() && expr->astOperand2()) { MathLib::bigint vals[4]; const bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]); const bool rhsHasKnownRange = getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]); if (!lhsHasKnownRange && !rhsHasKnownRange) return false; if (!lhsHasKnownRange || !rhsHasKnownRange) { if (minvalue) *minvalue = lhsHasKnownRange ? vals[0] : vals[2]; if (maxvalue) *maxvalue = lhsHasKnownRange ? vals[1] : vals[3]; } else { if (minvalue) *minvalue = vals[0] & vals[2]; if (maxvalue) *maxvalue = vals[1] & vals[3]; } return true; } if (expr->str() == "%" && expr->astOperand1() && expr->astOperand2()) { MathLib::bigint vals[4]; if (!getExpressionRange(expr->astOperand2(), &vals[2], &vals[3])) return false; if (vals[2] <= 0) return false; const bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]); if (lhsHasKnownRange && vals[0] < 0) return false; // If lhs has unknown value, it must be unsigned if (!lhsHasKnownRange && (!expr->astOperand1()->valueType() || expr->astOperand1()->valueType()->sign != ValueType::Sign::UNSIGNED)) return false; if (minvalue) *minvalue = 0; if (maxvalue) *maxvalue = vals[3] - 1; return true; } return false; } static void valueFlowRightShift(TokenList &tokenList, const Settings* settings) { for (Token *tok = tokenList.front(); tok; tok = tok->next()) { if (tok->str() != ">>") continue; if (tok->hasKnownValue()) continue; if (!tok->astOperand1() || !tok->astOperand2()) continue; if (!tok->astOperand2()->hasKnownValue()) continue; const MathLib::bigint rhsvalue = tok->astOperand2()->values().front().intvalue; if (rhsvalue < 0) continue; if (!tok->astOperand1()->valueType() || !tok->astOperand1()->valueType()->isIntegral()) continue; if (!tok->astOperand2()->valueType() || !tok->astOperand2()->valueType()->isIntegral()) continue; MathLib::bigint lhsmax=0; if (!getExpressionRange(tok->astOperand1(), nullptr, &lhsmax)) continue; if (lhsmax < 0) continue; int lhsbits; if ((tok->astOperand1()->valueType()->type == ValueType::Type::CHAR) || (tok->astOperand1()->valueType()->type == ValueType::Type::SHORT) || (tok->astOperand1()->valueType()->type == ValueType::Type::WCHAR_T) || (tok->astOperand1()->valueType()->type == ValueType::Type::BOOL) || (tok->astOperand1()->valueType()->type == ValueType::Type::INT)) lhsbits = settings->platform.int_bit; else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONG) lhsbits = settings->platform.long_bit; else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONGLONG) lhsbits = settings->platform.long_long_bit; else continue; if (rhsvalue >= lhsbits || rhsvalue >= MathLib::bigint_bits || (1ULL << rhsvalue) <= lhsmax) continue; ValueFlow::Value val(0); val.setKnown(); setTokenValue(tok, std::move(val), settings); } } static std::vector minUnsignedValue(const Token* tok, int depth = 8) { std::vector result; if (!tok) return result; if (depth < 0) return result; if (tok->hasKnownIntValue()) { result = {tok->values().front().intvalue}; } else if (!Token::Match(tok, "-|%|&|^") && tok->isConstOp() && tok->astOperand1() && tok->astOperand2()) { std::vector op1 = minUnsignedValue(tok->astOperand1(), depth - 1); std::vector op2 = minUnsignedValue(tok->astOperand2(), depth - 1); if (!op1.empty() && !op2.empty()) { result = calculate>(tok->str(), op1.front(), op2.front()); } } if (result.empty() && astIsUnsigned(tok)) result = {0}; return result; } static bool isConvertedToIntegral(const Token* tok, const Settings* settings) { if (!tok) return false; std::vector parentTypes = getParentValueTypes(tok, settings); if (parentTypes.empty()) return false; const ValueType& vt = parentTypes.front(); return vt.type != ValueType::UNKNOWN_INT && vt.isIntegral(); } static bool isSameToken(const Token* tok1, const Token* tok2) { if (!tok1 || !tok2) return false; if (tok1->exprId() != 0 && tok1->exprId() == tok2->exprId()) return true; if (tok1->hasKnownIntValue() && tok2->hasKnownIntValue()) return tok1->values().front().intvalue == tok2->values().front().intvalue; return false; } static void valueFlowImpossibleValues(TokenList& tokenList, const Settings* settings) { for (Token* tok = tokenList.front(); tok; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; if (Token::Match(tok, "true|false")) continue; if (astIsBool(tok) || Token::Match(tok, "%comp%")) { ValueFlow::Value lower{-1}; lower.bound = ValueFlow::Value::Bound::Upper; lower.setImpossible(); setTokenValue(tok, std::move(lower), settings); ValueFlow::Value upper{2}; upper.bound = ValueFlow::Value::Bound::Lower; upper.setImpossible(); setTokenValue(tok, std::move(upper), settings); } else if (astIsUnsigned(tok) && !astIsPointer(tok)) { std::vector minvalue = minUnsignedValue(tok); if (minvalue.empty()) continue; ValueFlow::Value value{std::max(0, minvalue.front()) - 1}; value.bound = ValueFlow::Value::Bound::Upper; value.setImpossible(); setTokenValue(tok, std::move(value), settings); } if (Token::simpleMatch(tok, "?") && Token::Match(tok->astOperand1(), "<|<=|>|>=")) { const Token* condTok = tok->astOperand1(); const Token* branchesTok = tok->astOperand2(); auto tokens = makeArray(condTok->astOperand1(), condTok->astOperand2()); auto branches = makeArray(branchesTok->astOperand1(), branchesTok->astOperand2()); bool flipped = false; if (std::equal(tokens.cbegin(), tokens.cend(), branches.crbegin(), &isSameToken)) flipped = true; else if (!std::equal(tokens.cbegin(), tokens.cend(), branches.cbegin(), &isSameToken)) continue; const bool isMin = Token::Match(condTok, "<|<=") ^ flipped; std::vector values; for (const Token* tok2 : tokens) { if (tok2->hasKnownIntValue()) { values.emplace_back(tok2->values().front()); } else { ValueFlow::Value symValue{}; symValue.valueType = ValueFlow::Value::ValueType::SYMBOLIC; symValue.tokvalue = tok2; values.push_back(symValue); std::copy_if(tok2->values().cbegin(), tok2->values().cend(), std::back_inserter(values), [](const ValueFlow::Value& v) { if (!v.isKnown()) return false; return v.isSymbolicValue(); }); } } for (ValueFlow::Value& value : values) { value.setImpossible(); if (isMin) { value.intvalue++; value.bound = ValueFlow::Value::Bound::Lower; } else { value.intvalue--; value.bound = ValueFlow::Value::Bound::Upper; } setTokenValue(tok, std::move(value), settings); } } else if (Token::simpleMatch(tok, "%") && tok->astOperand2() && tok->astOperand2()->hasKnownIntValue()) { ValueFlow::Value value{tok->astOperand2()->values().front()}; value.bound = ValueFlow::Value::Bound::Lower; value.setImpossible(); setTokenValue(tok, std::move(value), settings); } else if (Token::Match(tok, "abs|labs|llabs|fabs|fabsf|fabsl (")) { ValueFlow::Value value{-1}; value.bound = ValueFlow::Value::Bound::Upper; value.setImpossible(); setTokenValue(tok->next(), std::move(value), settings); } else if (Token::Match(tok, ". data|c_str (") && astIsContainerOwned(tok->astOperand1())) { const Library::Container* container = getLibraryContainer(tok->astOperand1()); if (!container) continue; if (!container->stdStringLike) continue; if (container->view) continue; ValueFlow::Value value{0}; value.setImpossible(); setTokenValue(tok->tokAt(2), std::move(value), settings); } else if (Token::Match(tok, "make_shared|make_unique <") && Token::simpleMatch(tok->linkAt(1), "> (")) { ValueFlow::Value value{0}; value.setImpossible(); setTokenValue(tok->linkAt(1)->next(), std::move(value), settings); } else if ((tokenList.isCPP() && Token::simpleMatch(tok, "this")) || tok->isUnaryOp("&")) { ValueFlow::Value value{0}; value.setImpossible(); setTokenValue(tok, std::move(value), settings); } else if (tok->isIncompleteVar() && tok->astParent() && tok->astParent()->isUnaryOp("-") && isConvertedToIntegral(tok->astParent(), settings)) { ValueFlow::Value value{0}; value.setImpossible(); setTokenValue(tok, std::move(value), settings); } } } static void valueFlowEnumValue(SymbolDatabase & symboldatabase, const Settings * settings) { for (Scope & scope : symboldatabase.scopeList) { if (scope.type != Scope::eEnum) continue; MathLib::bigint value = 0; bool prev_enum_is_known = true; for (Enumerator & enumerator : scope.enumeratorList) { if (enumerator.start) { Token* rhs = const_cast(enumerator.start->previous()->astOperand2()); ValueFlow::valueFlowConstantFoldAST(rhs, settings); if (rhs && rhs->hasKnownIntValue()) { enumerator.value = rhs->values().front().intvalue; enumerator.value_known = true; value = enumerator.value + 1; prev_enum_is_known = true; } else prev_enum_is_known = false; } else if (prev_enum_is_known) { enumerator.value = value++; enumerator.value_known = true; } } } } static void valueFlowGlobalConstVar(TokenList& tokenList, const Settings *settings) { // Get variable values... std::map vars; for (const Token* tok = tokenList.front(); tok; tok = tok->next()) { if (!tok->variable()) continue; // Initialization... if (tok == tok->variable()->nameToken() && !tok->variable()->isVolatile() && !tok->variable()->isArgument() && tok->variable()->isConst() && tok->valueType() && tok->valueType()->isIntegral() && tok->valueType()->pointer == 0 && tok->valueType()->constness == 1 && Token::Match(tok, "%name% =") && tok->next()->astOperand2() && tok->next()->astOperand2()->hasKnownIntValue()) { vars[tok->variable()] = tok->next()->astOperand2()->values().front(); } } // Set values.. for (Token* tok = tokenList.front(); tok; tok = tok->next()) { if (!tok->variable()) continue; const std::map::const_iterator var = vars.find(tok->variable()); if (var == vars.end()) continue; setTokenValue(tok, var->second, settings); } } static void valueFlowGlobalStaticVar(TokenList &tokenList, const Settings *settings) { // Get variable values... std::map vars; for (const Token *tok = tokenList.front(); tok; tok = tok->next()) { if (!tok->variable()) continue; // Initialization... if (tok == tok->variable()->nameToken() && tok->variable()->isStatic() && !tok->variable()->isConst() && tok->valueType() && tok->valueType()->isIntegral() && tok->valueType()->pointer == 0 && tok->valueType()->constness == 0 && Token::Match(tok, "%name% =") && tok->next()->astOperand2() && tok->next()->astOperand2()->hasKnownIntValue()) { vars[tok->variable()] = tok->next()->astOperand2()->values().front(); } else { // If variable is written anywhere in TU then remove it from vars if (!tok->astParent()) continue; if (Token::Match(tok->astParent(), "++|--|&") && !tok->astParent()->astOperand2()) vars.erase(tok->variable()); else if (tok->astParent()->isAssignmentOp()) { if (tok == tok->astParent()->astOperand1()) vars.erase(tok->variable()); else if (tokenList.isCPP() && Token::Match(tok->astParent()->tokAt(-2), "& %name% =")) vars.erase(tok->variable()); } else if (isLikelyStreamRead(tokenList.isCPP(), tok->astParent())) { vars.erase(tok->variable()); } else if (Token::Match(tok->astParent(), "[(,]")) vars.erase(tok->variable()); } } // Set values.. for (Token *tok = tokenList.front(); tok; tok = tok->next()) { if (!tok->variable()) continue; const std::map::const_iterator var = vars.find(tok->variable()); if (var == vars.end()) continue; setTokenValue(tok, var->second, settings); } } static ValuePtr makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings); static ValuePtr makeReverseAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings); static Analyzer::Result valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) { if (settings->debugnormal) setSourceLocation(value, loc, startToken); return valueFlowGenericForward(startToken, endToken, makeAnalyzer(exprTok, std::move(value), tokenlist, settings), *settings); } static Analyzer::Result valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, std::list values, const TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) { Analyzer::Result result{}; for (ValueFlow::Value& v : values) { result.update(valueFlowForward(startToken, endToken, exprTok, std::move(v), tokenlist, settings, loc)); } return result; } template static Analyzer::Result valueFlowForward(Token* startToken, const Token* exprTok, ValueOrValues v, TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) { const Token* endToken = nullptr; const Function* f = Scope::nestedInFunction(startToken->scope()); if (f && f->functionScope) endToken = f->functionScope->bodyEnd; return valueFlowForward(startToken, endToken, exprTok, std::move(v), tokenlist, settings, loc); } static Analyzer::Result valueFlowForwardRecursive(Token* top, const Token* exprTok, std::list values, const TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) { Analyzer::Result result{}; for (ValueFlow::Value& v : values) { if (settings->debugnormal) setSourceLocation(v, loc, top); result.update( valueFlowGenericForward(top, makeAnalyzer(exprTok, std::move(v), tokenlist, settings), *settings)); } return result; } static void valueFlowReverse(Token* tok, const Token* const endToken, const Token* const varToken, std::list values, const TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) { for (ValueFlow::Value& v : values) { if (settings->debugnormal) setSourceLocation(v, loc, tok); valueFlowGenericReverse(tok, endToken, makeReverseAnalyzer(varToken, std::move(v), tokenlist, settings), *settings); } } // Deprecated static void valueFlowReverse(const TokenList& tokenlist, Token* tok, const Token* const varToken, ValueFlow::Value val, const ValueFlow::Value& val2, ErrorLogger* /*errorLogger*/, const Settings* settings = nullptr, SourceLocation loc = SourceLocation::current()) { std::list values = {std::move(val)}; if (val2.varId != 0) values.push_back(val2); valueFlowReverse(tok, nullptr, varToken, std::move(values), tokenlist, settings, loc); } static bool isConditionKnown(const Token* tok, bool then) { const char* op = "||"; if (then) op = "&&"; const Token* parent = tok->astParent(); while (parent && (parent->str() == op || parent->str() == "!" || parent->isCast())) parent = parent->astParent(); const Token* top = tok->astTop(); if (top && Token::Match(top->previous(), "if|while|for (")) return parent == top || Token::simpleMatch(parent, ";"); return parent && parent->str() != op; } static const std::string& invertAssign(const std::string& assign) { static std::unordered_map lookup = {{"=", "="}, {"+=", "-="}, {"-=", "+="}, {"*=", "/="}, {"/=", "*="}, {"<<=", ">>="}, {">>=", "<<="}, {"^=", "^="}}; auto it = lookup.find(assign); if (it == lookup.end()) { return emptyString; } return it->second; } static std::string removeAssign(const std::string& assign) { return std::string{assign.cbegin(), assign.cend() - 1}; } template static T calculateAssign(const std::string& assign, const T& x, const U& y, bool* error = nullptr) { if (assign.empty() || assign.back() != '=') { if (error) *error = true; return T{}; } if (assign == "=") return y; return calculate(removeAssign(assign), x, y, error); } template static void assignValueIfMutable(T& x, const U& y) { x = y; } template static void assignValueIfMutable(const T& /*unused*/, const U& /*unused*/) {} template )> static bool evalAssignment(Value& lhsValue, const std::string& assign, const ValueFlow::Value& rhsValue) { bool error = false; if (lhsValue.isSymbolicValue() && rhsValue.isIntValue()) { if (assign != "+=" && assign != "-=") return false; assignValueIfMutable(lhsValue.intvalue, calculateAssign(assign, lhsValue.intvalue, rhsValue.intvalue, &error)); } else if (lhsValue.isIntValue() && rhsValue.isIntValue()) { assignValueIfMutable(lhsValue.intvalue, calculateAssign(assign, lhsValue.intvalue, rhsValue.intvalue, &error)); } else if (lhsValue.isFloatValue() && rhsValue.isIntValue()) { assignValueIfMutable(lhsValue.floatValue, calculateAssign(assign, lhsValue.floatValue, rhsValue.intvalue, &error)); } else { return false; } return !error; } static ValueFlow::Value::MoveKind isMoveOrForward(const Token* tok) { if (!tok) return ValueFlow::Value::MoveKind::NonMovedVariable; const Token* parent = tok->astParent(); if (!Token::simpleMatch(parent, "(")) return ValueFlow::Value::MoveKind::NonMovedVariable; const Token* ftok = parent->astOperand1(); if (!ftok) return ValueFlow::Value::MoveKind::NonMovedVariable; if (Token::simpleMatch(ftok->astOperand1(), "std :: move")) return ValueFlow::Value::MoveKind::MovedVariable; if (Token::simpleMatch(ftok->astOperand1(), "std :: forward")) return ValueFlow::Value::MoveKind::ForwardedVariable; // TODO: Check for cast return ValueFlow::Value::MoveKind::NonMovedVariable; } template struct SingleRange { T* x; T* begin() const { return x; } T* end() const { return x+1; } }; template SingleRange MakeSingleRange(T& x) { return {&x}; } class SelectValueFromVarIdMapRange { using M = std::unordered_map; struct Iterator { using iterator_category = std::forward_iterator_tag; using value_type = const ValueFlow::Value; using pointer = value_type *; using reference = value_type &; using difference_type = std::ptrdiff_t; explicit Iterator(const M::const_iterator & it) : mIt(it) {} reference operator*() const { return mIt->second; } pointer operator->() const { return &mIt->second; } Iterator &operator++() { // cppcheck-suppress postfixOperator - forward iterator needs to perform post-increment mIt++; return *this; } friend bool operator==(const Iterator &a, const Iterator &b) { return a.mIt == b.mIt; } friend bool operator!=(const Iterator &a, const Iterator &b) { return a.mIt != b.mIt; } private: M::const_iterator mIt; }; public: explicit SelectValueFromVarIdMapRange(const M *m) : mMap(m) {} Iterator begin() const { return Iterator(mMap->begin()); } Iterator end() const { return Iterator(mMap->end()); } private: const M *mMap; }; // Check if its an alias of the variable or is being aliased to this variable template static bool isAliasOf(const Variable * var, const Token *tok, nonneg int varid, const V& values, bool* inconclusive = nullptr) { if (tok->varId() == varid) return false; if (tok->varId() == 0) return false; if (isAliasOf(tok, varid, inconclusive)) return true; if (var && !var->isPointer()) return false; // Search through non value aliases return std::any_of(values.begin(), values.end(), [&](const ValueFlow::Value& val) { if (!val.isNonValue()) return false; if (val.isInconclusive()) return false; if (val.isLifetimeValue() && !val.isLocalLifetimeValue()) return false; if (val.isLifetimeValue() && val.lifetimeKind != ValueFlow::Value::LifetimeKind::Address) return false; if (!Token::Match(val.tokvalue, ".|&|*|%var%")) return false; return astHasVar(val.tokvalue, tok->varId()); }); } static bool bifurcate(const Token* tok, const std::set& varids, const Settings* settings, int depth = 20); static bool bifurcateVariableChanged(const Variable* var, const std::set& varids, const Token* start, const Token* end, const Settings* settings, int depth = 20) { bool result = false; const Token* tok = start; while ((tok = findVariableChanged( tok->next(), end, var->isPointer(), var->declarationId(), var->isGlobal(), settings, true))) { if (Token::Match(tok->astParent(), "%assign%")) { if (!bifurcate(tok->astParent()->astOperand2(), varids, settings, depth - 1)) return true; } else { result = true; } } return result; } static bool bifurcate(const Token* tok, const std::set& varids, const Settings* settings, int depth) { if (depth < 0) return false; if (!tok) return true; if (tok->hasKnownIntValue()) return true; if (tok->isConstOp()) return bifurcate(tok->astOperand1(), varids, settings, depth) && bifurcate(tok->astOperand2(), varids, settings, depth); if (tok->varId() != 0) { if (varids.count(tok->varId()) > 0) return true; const Variable* var = tok->variable(); if (!var) return false; const Token* start = var->declEndToken(); if (!start) return false; if (start->strAt(-1) == ")" || start->strAt(-1) == "}") return false; if (Token::Match(start, "; %varid% =", var->declarationId())) start = start->tokAt(2); if (var->isConst() || !bifurcateVariableChanged(var, varids, start, tok, settings, depth)) return var->isArgument() || bifurcate(start->astOperand2(), varids, settings, depth - 1); return false; } return false; } struct ValueFlowAnalyzer : Analyzer { const TokenList& tokenlist; const Settings* settings; ProgramMemoryState pms; explicit ValueFlowAnalyzer(const TokenList& t, const Settings* s = nullptr) : tokenlist(t), settings(s), pms(settings) {} virtual const ValueFlow::Value* getValue(const Token* tok) const = 0; virtual ValueFlow::Value* getValue(const Token* tok) = 0; virtual void makeConditional() = 0; virtual void addErrorPath(const Token* tok, const std::string& s) = 0; virtual bool match(const Token* tok) const = 0; virtual bool internalMatch(const Token* /*tok*/) const { return false; } virtual bool isAlias(const Token* tok, bool& inconclusive) const = 0; using ProgramState = ProgramMemory::Map; virtual ProgramState getProgramState() const = 0; virtual int getIndirect(const Token* tok) const { const ValueFlow::Value* value = getValue(tok); if (value) return value->indirect; return 0; } virtual bool isGlobal() const { return false; } virtual bool dependsOnThis() const { return false; } virtual bool isVariable() const { return false; } bool isCPP() const { return tokenlist.isCPP(); } const Settings* getSettings() const { return settings; } // Returns Action::Match if its an exact match, return Action::Read if it partially matches the lifetime Action analyzeLifetime(const Token* tok) const { if (!tok) return Action::None; if (match(tok)) return Action::Match; if (Token::simpleMatch(tok, ".") && analyzeLifetime(tok->astOperand1()) != Action::None) return Action::Read; if (astIsRHS(tok) && Token::simpleMatch(tok->astParent(), ".")) return analyzeLifetime(tok->astParent()); return Action::None; } struct ConditionState { bool dependent = true; bool unknown = true; bool isUnknownDependent() const { return unknown && dependent; } }; std::unordered_map getSymbols(const Token* tok) const { std::unordered_map result; if (!tok) return result; for (const ValueFlow::Value& v : tok->values()) { if (!v.isSymbolicValue()) continue; if (v.isImpossible()) continue; if (!v.tokvalue) continue; if (v.tokvalue->exprId() == 0) continue; if (match(v.tokvalue)) continue; result[v.tokvalue->exprId()] = v.tokvalue; } return result; } ConditionState analyzeCondition(const Token* tok, int depth = 20) const { ConditionState result; if (!tok) return result; if (depth < 0) return result; depth--; if (analyze(tok, Direction::Forward).isRead()) { result.dependent = true; result.unknown = false; return result; } if (tok->hasKnownIntValue() || tok->isLiteral()) { result.dependent = false; result.unknown = false; return result; } if (Token::Match(tok, "%cop%")) { if (isLikelyStream(isCPP(), tok->astOperand1())) { result.dependent = false; return result; } ConditionState lhs = analyzeCondition(tok->astOperand1(), depth - 1); if (lhs.isUnknownDependent()) return lhs; ConditionState rhs = analyzeCondition(tok->astOperand2(), depth - 1); if (rhs.isUnknownDependent()) return rhs; if (Token::Match(tok, "%comp%")) result.dependent = lhs.dependent && rhs.dependent; else result.dependent = lhs.dependent || rhs.dependent; result.unknown = lhs.unknown || rhs.unknown; return result; } if (Token::Match(tok->previous(), "%name% (")) { std::vector args = getArguments(tok->previous()); if (Token::Match(tok->tokAt(-2), ". %name% (")) { args.push_back(tok->tokAt(-2)->astOperand1()); } result.dependent = std::any_of(args.cbegin(), args.cend(), [&](const Token* arg) { ConditionState cs = analyzeCondition(arg, depth - 1); return cs.dependent; }); if (result.dependent) { // Check if we can evaluate the function if (!evaluate(Evaluate::Integral, tok).empty()) result.unknown = false; } return result; } std::unordered_map symbols = getSymbols(tok); result.dependent = false; for (auto&& p : symbols) { const Token* arg = p.second; ConditionState cs = analyzeCondition(arg, depth - 1); result.dependent = cs.dependent; if (result.dependent) break; } if (result.dependent) { // Check if we can evaluate the token if (!evaluate(Evaluate::Integral, tok).empty()) result.unknown = false; } return result; } virtual Action isModified(const Token* tok) const { const Action read = Action::Read; const ValueFlow::Value* value = getValue(tok); if (value) { // Moving a moved value won't change the moved value if (value->isMovedValue() && isMoveOrForward(tok) != ValueFlow::Value::MoveKind::NonMovedVariable) return read; // Inserting elements to container won't change the lifetime if (astIsContainer(tok) && value->isLifetimeValue() && contains({Library::Container::Action::PUSH, Library::Container::Action::INSERT, Library::Container::Action::CHANGE_INTERNAL}, astContainerAction(tok))) return read; } bool inconclusive = false; if (isVariableChangedByFunctionCall(tok, getIndirect(tok), getSettings(), &inconclusive)) return read | Action::Invalid; if (inconclusive) return read | Action::Inconclusive; if (isVariableChanged(tok, getIndirect(tok), getSettings(), isCPP())) { if (Token::Match(tok->astParent(), "*|[|.|++|--")) return read | Action::Invalid; // Check if its assigned to the same value if (value && !value->isImpossible() && Token::simpleMatch(tok->astParent(), "=") && astIsLHS(tok) && astIsIntegral(tok->astParent()->astOperand2(), false)) { std::vector result = evaluateInt(tok->astParent()->astOperand2()); if (!result.empty() && value->equalTo(result.front())) return Action::Idempotent; } return Action::Invalid; } return read; } virtual Action isAliasModified(const Token* tok, int indirect = -1) const { // Lambda function call if (Token::Match(tok, "%var% (")) // TODO: Check if modified in the lambda function return Action::Invalid; if (indirect == -1) { indirect = 0; if (const ValueType* vt = tok->valueType()) { indirect = vt->pointer; if (vt->type == ValueType::ITERATOR) ++indirect; } } for (int i = 0; i <= indirect; ++i) if (isVariableChanged(tok, i, getSettings(), isCPP())) return Action::Invalid; return Action::None; } virtual Action isThisModified(const Token* tok) const { if (isThisChanged(tok, 0, getSettings(), isCPP())) return Action::Invalid; return Action::None; } Action isGlobalModified(const Token* tok) const { if (tok->function()) { if (!tok->function()->isConstexpr() && !isConstFunctionCall(tok, getSettings()->library)) return Action::Invalid; } else if (getSettings()->library.getFunction(tok)) { // Assume library function doesn't modify user-global variables return Action::None; } else if (Token::simpleMatch(tok->astParent(), ".") && astIsContainer(tok->astParent()->astOperand1())) { // Assume container member function doesn't modify user-global variables return Action::None; } else if (tok->tokType() == Token::eType && astIsPrimitive(tok->next())) { // Function cast does not modify global variables return Action::None; } else if (!tok->isKeyword() && Token::Match(tok, "%name% (")) { return Action::Invalid; } return Action::None; } static const std::string& getAssign(const Token* tok, Direction d) { if (d == Direction::Forward) return tok->str(); return invertAssign(tok->str()); } virtual Action isWritable(const Token* tok, Direction d) const { const ValueFlow::Value* value = getValue(tok); if (!value) return Action::None; if (!(value->isIntValue() || value->isFloatValue() || value->isSymbolicValue() || value->isLifetimeValue())) return Action::None; const Token* parent = tok->astParent(); // Only if its invertible if (value->isImpossible() && !Token::Match(parent, "+=|-=|*=|++|--")) return Action::None; if (value->isLifetimeValue()) { if (value->lifetimeKind != ValueFlow::Value::LifetimeKind::Iterator) return Action::None; if (!Token::Match(parent, "++|--|+=")) return Action::None; return Action::Read | Action::Write; } if (parent && parent->isAssignmentOp() && astIsLHS(tok)) { const Token* rhs = parent->astOperand2(); std::vector result = evaluateInt(rhs); if (!result.empty()) { ValueFlow::Value rhsValue{result.front()}; Action a; if (!evalAssignment(*value, getAssign(parent, d), rhsValue)) a = Action::Invalid; else a = Action::Write; if (parent->str() != "=") { a |= Action::Read | Action::Incremental; } else { if (!value->isImpossible() && value->equalValue(rhsValue)) a = Action::Idempotent; if (tok->exprId() != 0 && findAstNode(rhs, [&](const Token* child) { return tok->exprId() == child->exprId(); })) a |= Action::Incremental; } return a; } } // increment/decrement if (Token::Match(tok->astParent(), "++|--")) { return Action::Read | Action::Write | Action::Incremental; } return Action::None; } virtual void writeValue(ValueFlow::Value* value, const Token* tok, Direction d) const { if (!value) return; if (!tok->astParent()) return; // Lifetime value doesn't change if (value->isLifetimeValue()) return; if (tok->astParent()->isAssignmentOp()) { const Token* rhs = tok->astParent()->astOperand2(); std::vector result = evaluateInt(rhs); assert(!result.empty()); ValueFlow::Value rhsValue{result.front()}; if (evalAssignment(*value, getAssign(tok->astParent(), d), rhsValue)) { std::string info("Compound assignment '" + tok->astParent()->str() + "', assigned value is " + value->infoString()); if (tok->astParent()->str() == "=") value->errorPath.clear(); value->errorPath.emplace_back(tok, std::move(info)); } else { assert(false && "Writable value cannot be evaluated"); // TODO: Don't set to zero value->intvalue = 0; } } else if (tok->astParent()->tokType() == Token::eIncDecOp) { bool inc = tok->astParent()->str() == "++"; const std::string opName(inc ? "incremented" : "decremented"); if (d == Direction::Reverse) inc = !inc; value->intvalue += (inc ? 1 : -1); value->errorPath.emplace_back(tok, tok->str() + " is " + opName + "', new value is " + value->infoString()); } } virtual bool useSymbolicValues() const { return true; } const Token* findMatch(const Token* tok) const { return findAstNode(tok, [&](const Token* child) { return match(child); }); } bool isSameSymbolicValue(const Token* tok, ValueFlow::Value* value = nullptr) const { if (!useSymbolicValues()) return false; if (Token::Match(tok, "%assign%")) return false; const ValueFlow::Value* currValue = getValue(tok); if (!currValue) return false; // If the same symbolic value is already there then skip if (currValue->isSymbolicValue() && std::any_of(tok->values().cbegin(), tok->values().cend(), [&](const ValueFlow::Value& v) { return v.isSymbolicValue() && currValue->equalValue(v); })) return false; const bool isPoint = currValue->bound == ValueFlow::Value::Bound::Point && currValue->isIntValue(); const bool exact = !currValue->isIntValue() || currValue->isImpossible(); for (const ValueFlow::Value& v : tok->values()) { if (!v.isSymbolicValue()) continue; if (currValue->equalValue(v)) continue; const bool toImpossible = v.isImpossible() && currValue->isKnown(); if (!v.isKnown() && !toImpossible) continue; if (exact && v.intvalue != 0 && !isPoint) continue; std::vector r; ValueFlow::Value::Bound bound = currValue->bound; if (match(v.tokvalue)) { r = {currValue->intvalue}; } else if (!exact && findMatch(v.tokvalue)) { r = evaluate(Evaluate::Integral, v.tokvalue, tok); if (bound == ValueFlow::Value::Bound::Point) bound = v.bound; } if (!r.empty()) { if (value) { value->errorPath.insert(value->errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend()); value->intvalue = r.front() + v.intvalue; if (toImpossible) value->setImpossible(); value->bound = bound; } return true; } } return false; } Action analyzeMatch(const Token* tok, Direction d) const { const Token* parent = tok->astParent(); if (d == Direction::Reverse && isGlobal() && !dependsOnThis() && Token::Match(parent, ". %name% (")) { Action a = isGlobalModified(parent->next()); if (a != Action::None) return a; } if ((astIsPointer(tok) || astIsSmartPointer(tok)) && (Token::Match(parent, "*|[") || (parent && parent->originalName() == "->")) && getIndirect(tok) <= 0) return Action::Read; Action w = isWritable(tok, d); if (w != Action::None) return w; // Check for modifications by function calls return isModified(tok); } Action analyzeToken(const Token* ref, const Token* tok, Direction d, bool inconclusiveRef) const { if (!ref) return Action::None; // If its an inconclusiveRef then ref != tok assert(!inconclusiveRef || ref != tok); bool inconclusive = false; if (match(ref)) { if (inconclusiveRef) { Action a = isModified(tok); if (a.isModified() || a.isInconclusive()) return Action::Inconclusive; } else { return analyzeMatch(tok, d) | Action::Match; } } else if (ref->isUnaryOp("*") && !match(ref->astOperand1())) { const Token* lifeTok = nullptr; for (const ValueFlow::Value& v:ref->astOperand1()->values()) { if (!v.isLocalLifetimeValue()) continue; if (lifeTok) return Action::None; lifeTok = v.tokvalue; } if (!lifeTok) return Action::None; Action la = analyzeLifetime(lifeTok); if (la.matches()) { Action a = Action::Read; if (isModified(tok).isModified()) a = Action::Invalid; if (Token::Match(tok->astParent(), "%assign%") && astIsLHS(tok)) a |= Action::Invalid; if (inconclusiveRef && a.isModified()) return Action::Inconclusive; return a; } if (la.isRead()) { return isAliasModified(tok); } return Action::None; } else if (isAlias(ref, inconclusive)) { inconclusive |= inconclusiveRef; Action a = isAliasModified(tok); if (inconclusive && a.isModified()) return Action::Inconclusive; return a; } if (isSameSymbolicValue(ref)) return Action::Read | Action::SymbolicMatch; return Action::None; } Action analyze(const Token* tok, Direction d) const override { if (invalid()) return Action::Invalid; // Follow references auto refs = followAllReferences(tok); const bool inconclusiveRefs = refs.size() != 1; if (std::none_of(refs.cbegin(), refs.cend(), [&](const ReferenceToken& ref) { return tok == ref.token; })) refs.emplace_back(ReferenceToken{tok, {}}); for (const ReferenceToken& ref:refs) { Action a = analyzeToken(ref.token, tok, d, inconclusiveRefs && ref.token != tok); if (internalMatch(ref.token)) a |= Action::Internal; if (a != Action::None) return a; } if (dependsOnThis() && exprDependsOnThis(tok, !isVariable())) return isThisModified(tok); // bailout: global non-const variables if (isGlobal() && !dependsOnThis() && Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) { return isGlobalModified(tok); } return Action::None; } template std::vector evaluateInt(const Token* tok, F getProgramMemory) const { if (tok->hasKnownIntValue()) return {static_cast(tok->values().front().intvalue)}; std::vector result; ProgramMemory pm = getProgramMemory(); if (Token::Match(tok, "&&|%oror%")) { if (conditionIsTrue(tok, pm, getSettings())) result.push_back(1); if (conditionIsFalse(tok, pm, getSettings())) result.push_back(0); } else { MathLib::bigint out = 0; bool error = false; execute(tok, pm, &out, &error, getSettings()); if (!error) result.push_back(out); } return result; } std::vector evaluateInt(const Token* tok) const { return evaluateInt(tok, [&] { return ProgramMemory{getProgramState()}; }); } std::vector evaluate(Evaluate e, const Token* tok, const Token* ctx = nullptr) const override { if (e == Evaluate::Integral) { return evaluateInt(tok, [&] { return pms.get(tok, ctx, getProgramState()); }); } if (e == Evaluate::ContainerEmpty) { const ValueFlow::Value* value = ValueFlow::findValue(tok->values(), nullptr, [](const ValueFlow::Value& v) { return v.isKnown() && v.isContainerSizeValue(); }); if (value) return {value->intvalue == 0}; ProgramMemory pm = pms.get(tok, ctx, getProgramState()); MathLib::bigint out = 0; if (pm.getContainerEmptyValue(tok->exprId(), out)) return {static_cast(out)}; return {}; } return {}; } void assume(const Token* tok, bool state, unsigned int flags) override { // Update program state pms.removeModifiedVars(tok); pms.addState(tok, getProgramState()); pms.assume(tok, state, flags & Assume::ContainerEmpty); bool isCondBlock = false; const Token* parent = tok->astParent(); if (parent) { isCondBlock = Token::Match(parent->previous(), "if|while ("); } if (isCondBlock) { const Token* startBlock = parent->link()->next(); if (Token::simpleMatch(startBlock, ";") && Token::simpleMatch(parent->tokAt(-2), "} while (")) startBlock = parent->linkAt(-2); const Token* endBlock = startBlock->link(); if (state) { pms.removeModifiedVars(endBlock); pms.addState(endBlock->previous(), getProgramState()); } else { if (Token::simpleMatch(endBlock, "} else {")) pms.addState(endBlock->linkAt(2)->previous(), getProgramState()); } } if (!(flags & Assume::Quiet)) { if (flags & Assume::ContainerEmpty) { std::string s = state ? "empty" : "not empty"; addErrorPath(tok, "Assuming container is " + s); } else { std::string s = bool_to_string(state); addErrorPath(tok, "Assuming condition is " + s); } } if (!(flags & Assume::Absolute)) makeConditional(); } virtual void internalUpdate(Token* /*tok*/, const ValueFlow::Value& /*v*/, Direction /*d*/) { assert(false && "Internal update unimplemented."); } void update(Token* tok, Action a, Direction d) override { ValueFlow::Value* value = getValue(tok); if (!value) return; ValueFlow::Value localValue; if (a.isSymbolicMatch()) { // Make a copy of the value to modify it localValue = *value; value = &localValue; isSameSymbolicValue(tok, &localValue); } if (a.isInternal()) internalUpdate(tok, *value, d); // Read first when moving forward if (d == Direction::Forward && a.isRead()) setTokenValue(tok, *value, getSettings()); if (a.isInconclusive()) lowerToInconclusive(); if (a.isWrite() && tok->astParent()) { writeValue(value, tok, d); } // Read last when moving in reverse if (d == Direction::Reverse && a.isRead()) setTokenValue(tok, *value, getSettings()); } ValuePtr reanalyze(Token* /*tok*/, const std::string& /*msg*/) const override { return {}; } }; struct SingleValueFlowAnalyzer : ValueFlowAnalyzer { std::unordered_map varids; std::unordered_map aliases; ValueFlow::Value value; SingleValueFlowAnalyzer(ValueFlow::Value v, const TokenList& t, const Settings* s) : ValueFlowAnalyzer(t, s), value(std::move(v)) {} const std::unordered_map& getVars() const { return varids; } const std::unordered_map& getAliasedVars() const { return aliases; } const ValueFlow::Value* getValue(const Token* /*tok*/) const override { return &value; } ValueFlow::Value* getValue(const Token* /*tok*/) override { return &value; } void makeConditional() override { value.conditional = true; } bool useSymbolicValues() const override { if (value.isUninitValue()) return false; if (value.isLifetimeValue()) return false; return true; } void addErrorPath(const Token* tok, const std::string& s) override { value.errorPath.emplace_back(tok, s); } bool isAlias(const Token* tok, bool& inconclusive) const override { if (value.isLifetimeValue()) return false; for (const auto& m: { std::ref(getVars()), std::ref(getAliasedVars()) }) { for (const auto& p:m.get()) { nonneg int const varid = p.first; const Variable* var = p.second; if (tok->varId() == varid) return true; if (isAliasOf(var, tok, varid, MakeSingleRange(value), &inconclusive)) return true; } } return false; } bool isGlobal() const override { const auto& vars = getVars(); return std::any_of(vars.cbegin(), vars.cend(), [] (const std::pair& p) { const Variable* var = p.second; return !var->isLocal() && !var->isArgument() && !var->isConst(); }); } bool lowerToPossible() override { if (value.isImpossible()) return false; value.changeKnownToPossible(); return true; } bool lowerToInconclusive() override { if (value.isImpossible()) return false; value.setInconclusive(); return true; } bool isConditional() const override { if (value.conditional) return true; if (value.condition) return !value.isKnown() && !value.isImpossible(); return false; } bool stopOnCondition(const Token* condTok) const override { if (value.isNonValue()) return false; if (value.isImpossible()) return false; if (isConditional() && !value.isKnown() && !value.isImpossible()) return true; if (value.isSymbolicValue()) return false; ConditionState cs = analyzeCondition(condTok); return cs.isUnknownDependent(); } bool updateScope(const Token* endBlock, bool /*modified*/) const override { const Scope* scope = endBlock->scope(); if (!scope) return false; if (scope->type == Scope::eLambda) return value.isLifetimeValue(); if (scope->type == Scope::eIf || scope->type == Scope::eElse || scope->type == Scope::eWhile || scope->type == Scope::eFor) { if (value.isKnown() || value.isImpossible()) return true; if (value.isLifetimeValue()) return true; if (isConditional()) return false; const Token* condTok = getCondTokFromEnd(endBlock); std::set varids2; std::transform(getVars().cbegin(), getVars().cend(), std::inserter(varids2, varids2.begin()), SelectMapKeys{}); return bifurcate(condTok, varids2, getSettings()); } return false; } ValuePtr reanalyze(Token* tok, const std::string& msg) const override { ValueFlow::Value newValue = value; newValue.errorPath.emplace_back(tok, msg); return makeAnalyzer(tok, std::move(newValue), tokenlist, settings); } }; struct ExpressionAnalyzer : SingleValueFlowAnalyzer { const Token* expr; bool local = true; bool unknown{}; bool dependOnThis{}; bool uniqueExprId{}; ExpressionAnalyzer(const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s) : SingleValueFlowAnalyzer(std::move(val), t, s), expr(e) { assert(e && e->exprId() != 0 && "Not a valid expression"); dependOnThis = exprDependsOnThis(expr); setupExprVarIds(expr); if (value.isSymbolicValue()) { dependOnThis |= exprDependsOnThis(value.tokvalue); setupExprVarIds(value.tokvalue); } uniqueExprId = expr->isUniqueExprId() && (Token::Match(expr, "%cop%") || !isVariableChanged(expr, 0, s, t.isCPP())); } static bool nonLocal(const Variable* var, bool deref) { return !var || (!var->isLocal() && !var->isArgument()) || (deref && var->isArgument() && var->isPointer()) || var->isStatic() || var->isReference() || var->isExtern(); } void setupExprVarIds(const Token* start, int depth = 0) { const int maxDepth = 4; if (depth > maxDepth) return; visitAstNodes(start, [&](const Token* tok) { const bool top = depth == 0 && tok == start; const bool ispointer = astIsPointer(tok) || astIsSmartPointer(tok) || astIsIterator(tok); if (!top || !ispointer || value.indirect != 0) { for (const ValueFlow::Value& v : tok->values()) { if (!(v.isLocalLifetimeValue() || (ispointer && v.isSymbolicValue() && v.isKnown()))) continue; if (!v.tokvalue) continue; if (v.tokvalue == tok) continue; setupExprVarIds(v.tokvalue, depth + 1); } } if (depth == 0 && tok->isIncompleteVar()) { // TODO: Treat incomplete var as global, but we need to update // the alias variables to just expr ids instead of requiring // Variable unknown = true; return ChildrenToVisit::none; } if (tok->varId() > 0) { varids[tok->varId()] = tok->variable(); if (!Token::simpleMatch(tok->previous(), ".")) { const Variable* var = tok->variable(); if (var && var->isReference() && var->isLocal() && Token::Match(var->nameToken(), "%var% [=(]") && !isGlobalData(var->nameToken()->next()->astOperand2(), isCPP())) return ChildrenToVisit::none; const bool deref = tok->astParent() && (tok->astParent()->isUnaryOp("*") || (tok->astParent()->str() == "[" && tok == tok->astParent()->astOperand1())); local &= !nonLocal(tok->variable(), deref); } } return ChildrenToVisit::op1_and_op2; }); } virtual bool skipUniqueExprIds() const { return true; } bool invalid() const override { if (skipUniqueExprIds() && uniqueExprId) return true; return unknown; } ProgramState getProgramState() const override { ProgramState ps; ps[expr] = value; return ps; } bool match(const Token* tok) const override { return tok->exprId() == expr->exprId(); } bool dependsOnThis() const override { return dependOnThis; } bool isGlobal() const override { return !local; } bool isVariable() const override { return expr->varId() > 0; } Action isAliasModified(const Token* tok, int indirect) const override { if (value.isSymbolicValue() && tok->exprId() == value.tokvalue->exprId()) indirect = 0; return SingleValueFlowAnalyzer::isAliasModified(tok, indirect); } }; struct SameExpressionAnalyzer : ExpressionAnalyzer { SameExpressionAnalyzer(const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s) : ExpressionAnalyzer(e, std::move(val), t, s) {} bool skipUniqueExprIds() const override { return false; } bool match(const Token* tok) const override { return isSameExpression(isCPP(), true, expr, tok, getSettings()->library, true, true); } }; struct OppositeExpressionAnalyzer : ExpressionAnalyzer { bool isNot{}; OppositeExpressionAnalyzer(bool pIsNot, const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s) : ExpressionAnalyzer(e, std::move(val), t, s), isNot(pIsNot) {} bool skipUniqueExprIds() const override { return false; } bool match(const Token* tok) const override { return isOppositeCond(isNot, isCPP(), expr, tok, getSettings()->library, true, true); } }; struct SubExpressionAnalyzer : ExpressionAnalyzer { using PartialReadContainer = std::vector>; // A shared_ptr is used so partial reads can be captured even after forking std::shared_ptr partialReads; SubExpressionAnalyzer(const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s) : ExpressionAnalyzer(e, std::move(val), t, s), partialReads(std::make_shared()) {} virtual bool submatch(const Token* tok, bool exact = true) const = 0; bool isAlias(const Token* tok, bool& inconclusive) const override { if (tok->exprId() == expr->exprId() && tok->astParent() && submatch(tok->astParent(), false)) return false; return ExpressionAnalyzer::isAlias(tok, inconclusive); } bool match(const Token* tok) const override { return tok->astOperand1() && tok->astOperand1()->exprId() == expr->exprId() && submatch(tok); } bool internalMatch(const Token* tok) const override { return tok->exprId() == expr->exprId() && !(astIsLHS(tok) && submatch(tok->astParent(), false)); } void internalUpdate(Token* tok, const ValueFlow::Value& v, Direction /*d*/) override { partialReads->emplace_back(tok, v); } // No reanalysis for subexpression ValuePtr reanalyze(Token* /*tok*/, const std::string& /*msg*/) const override { return {}; } }; struct MemberExpressionAnalyzer : SubExpressionAnalyzer { std::string varname; MemberExpressionAnalyzer(std::string varname, const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s) : SubExpressionAnalyzer(e, std::move(val), t, s), varname(std::move(varname)) {} bool submatch(const Token* tok, bool exact) const override { if (!Token::Match(tok, ". %var%")) return false; if (!exact) return true; return tok->next()->str() == varname; } }; enum class LifetimeCapture { Undefined, ByValue, ByReference }; static std::string lifetimeType(const Token *tok, const ValueFlow::Value *val) { std::string result; if (!val) return "object"; switch (val->lifetimeKind) { case ValueFlow::Value::LifetimeKind::Lambda: result = "lambda"; break; case ValueFlow::Value::LifetimeKind::Iterator: result = "iterator"; break; case ValueFlow::Value::LifetimeKind::Object: case ValueFlow::Value::LifetimeKind::SubObject: case ValueFlow::Value::LifetimeKind::Address: if (astIsPointer(tok)) result = "pointer"; else if (Token::simpleMatch(tok, "=") && astIsPointer(tok->astOperand2())) result = "pointer"; else result = "object"; break; } return result; } std::string ValueFlow::lifetimeMessage(const Token *tok, const ValueFlow::Value *val, ErrorPath &errorPath) { const Token *tokvalue = val ? val->tokvalue : nullptr; const Variable *tokvar = tokvalue ? tokvalue->variable() : nullptr; const Token *vartok = tokvar ? tokvar->nameToken() : nullptr; const bool classVar = tokvar ? (!tokvar->isLocal() && !tokvar->isArgument() && !tokvar->isGlobal()) : false; std::string type = lifetimeType(tok, val); std::string msg = type; if (vartok) { if (!classVar) errorPath.emplace_back(vartok, "Variable created here."); const Variable * var = vartok->variable(); if (var) { std::string submessage; switch (val->lifetimeKind) { case ValueFlow::Value::LifetimeKind::SubObject: case ValueFlow::Value::LifetimeKind::Object: case ValueFlow::Value::LifetimeKind::Address: if (type == "pointer") submessage = " to local variable"; else submessage = " that points to local variable"; break; case ValueFlow::Value::LifetimeKind::Lambda: submessage = " that captures local variable"; break; case ValueFlow::Value::LifetimeKind::Iterator: submessage = " to local container"; break; } if (classVar) submessage.replace(submessage.find("local"), 5, "member"); msg += submessage + " '" + var->name() + "'"; } } return msg; } std::vector ValueFlow::getLifetimeObjValues(const Token* tok, bool inconclusive, MathLib::bigint path) { std::vector result; auto pred = [&](const ValueFlow::Value& v) { if (!v.isLocalLifetimeValue() && !(path != 0 && v.isSubFunctionLifetimeValue())) return false; if (!inconclusive && v.isInconclusive()) return false; if (!v.tokvalue) return false; if (path >= 0 && v.path != 0 && v.path != path) return false; return true; }; std::copy_if(tok->values().cbegin(), tok->values().cend(), std::back_inserter(result), pred); return result; } static bool hasUniqueOwnership(const Token* tok) { if (!tok) return false; const Variable* var = tok->variable(); if (var && var->isArray() && !var->isArgument()) return true; if (astIsPointer(tok)) return false; if (astIsUniqueSmartPointer(tok)) return true; if (astIsContainerOwned(tok)) return true; return false; } // Check if dereferencing an object that doesn't have unique ownership static bool derefShared(const Token* tok) { if (!tok) return false; if (!tok->isUnaryOp("*") && tok->str() != "[" && tok->str() != ".") return false; if (tok->str() == "." && tok->originalName() != "->") return false; const Token* ptrTok = tok->astOperand1(); return !hasUniqueOwnership(ptrTok); } ValueFlow::Value ValueFlow::getLifetimeObjValue(const Token *tok, bool inconclusive) { std::vector values = ValueFlow::getLifetimeObjValues(tok, inconclusive); // There should only be one lifetime if (values.size() != 1) return ValueFlow::Value{}; return values.front(); } template static std::vector getLifetimeTokens(const Token* tok, bool escape, ValueFlow::Value::ErrorPath errorPath, Predicate pred, int depth = 20) { if (!tok) return std::vector {}; if (Token::simpleMatch(tok, "...")) return std::vector{}; const Variable *var = tok->variable(); if (pred(tok)) return {{tok, std::move(errorPath)}}; if (depth < 0) return {{tok, std::move(errorPath)}}; if (var && var->declarationId() == tok->varId()) { if (var->isReference() || var->isRValueReference()) { const Token * const varDeclEndToken = var->declEndToken(); if (!varDeclEndToken) return {{tok, true, std::move(errorPath)}}; if (var->isArgument()) { errorPath.emplace_back(varDeclEndToken, "Passed to reference."); return {{tok, true, std::move(errorPath)}}; } if (Token::simpleMatch(varDeclEndToken, "=")) { errorPath.emplace_back(varDeclEndToken, "Assigned to reference."); const Token *vartok = varDeclEndToken->astOperand2(); const bool temporary = isTemporary(true, vartok, nullptr, true); const bool nonlocal = var->isStatic() || var->isGlobal(); if (vartok == tok || (nonlocal && temporary) || (!escape && (var->isConst() || var->isRValueReference()) && temporary)) return {{tok, true, std::move(errorPath)}}; if (vartok) return getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1); } else if (Token::simpleMatch(var->nameToken()->astParent(), ":") && var->nameToken()->astParent()->astParent() && Token::simpleMatch(var->nameToken()->astParent()->astParent()->previous(), "for (")) { errorPath.emplace_back(var->nameToken(), "Assigned to reference."); const Token* vartok = var->nameToken(); if (vartok == tok) return {{tok, true, std::move(errorPath)}}; const Token* contok = var->nameToken()->astParent()->astOperand2(); if (astIsContainer(contok)) return getLifetimeTokens(contok, escape, std::move(errorPath), pred, depth - 1); return std::vector{}; } else { return std::vector {}; } } } else if (Token::Match(tok->previous(), "%name% (")) { const Function *f = tok->previous()->function(); if (f) { if (!Function::returnsReference(f)) return {{tok, std::move(errorPath)}}; std::vector result; std::vector returns = Function::findReturns(f); for (const Token* returnTok : returns) { if (returnTok == tok) continue; for (ValueFlow::LifetimeToken& lt : getLifetimeTokens(returnTok, escape, errorPath, pred, depth - returns.size())) { const Token* argvarTok = lt.token; const Variable* argvar = argvarTok->variable(); if (!argvar) continue; const Token* argTok = nullptr; if (argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) { const int n = getArgumentPos(argvar, f); if (n < 0) return std::vector {}; std::vector args = getArguments(tok->previous()); // TODO: Track lifetimes of default parameters if (n >= args.size()) return std::vector {}; argTok = args[n]; lt.errorPath.emplace_back(returnTok, "Return reference."); lt.errorPath.emplace_back(tok->previous(), "Called function passing '" + argTok->expressionString() + "'."); } else if (Token::Match(tok->tokAt(-2), ". %name% (") && !derefShared(tok->tokAt(-2)) && exprDependsOnThis(argvarTok)) { argTok = tok->tokAt(-2)->astOperand1(); lt.errorPath.emplace_back(returnTok, "Return reference that depends on 'this'."); lt.errorPath.emplace_back(tok->previous(), "Calling member function on '" + argTok->expressionString() + "'."); } if (argTok) { std::vector arglts = ValueFlow::LifetimeToken::setInconclusive( getLifetimeTokens(argTok, escape, std::move(lt.errorPath), pred, depth - returns.size()), returns.size() > 1); result.insert(result.end(), arglts.cbegin(), arglts.cend()); } } } return result; } if (Token::Match(tok->tokAt(-2), ". %name% (") && tok->tokAt(-2)->originalName() != "->" && astIsContainer(tok->tokAt(-2)->astOperand1())) { const Library::Container* library = getLibraryContainer(tok->tokAt(-2)->astOperand1()); const Library::Container::Yield y = library->getYield(tok->previous()->str()); if (y == Library::Container::Yield::AT_INDEX || y == Library::Container::Yield::ITEM) { errorPath.emplace_back(tok->previous(), "Accessing container."); return ValueFlow::LifetimeToken::setAddressOf( getLifetimeTokens(tok->tokAt(-2)->astOperand1(), escape, std::move(errorPath), pred, depth - 1), false); } } } else if (Token::Match(tok, ".|::|[") || tok->isUnaryOp("*")) { const Token *vartok = tok; while (vartok) { if (vartok->str() == "[" || vartok->originalName() == "->" || vartok->isUnaryOp("*")) vartok = vartok->astOperand1(); else if (vartok->str() == "." || vartok->str() == "::") vartok = vartok->astOperand2(); else break; } if (!vartok) return {{tok, std::move(errorPath)}}; if (derefShared(vartok->astParent())) { for (const ValueFlow::Value &v : vartok->values()) { if (!v.isLocalLifetimeValue()) continue; if (v.tokvalue == tok) continue; errorPath.insert(errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend()); return getLifetimeTokens(v.tokvalue, escape, std::move(errorPath), pred, depth - 1); } } else { return ValueFlow::LifetimeToken::setAddressOf(getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1), !(astIsContainer(vartok) && Token::simpleMatch(vartok->astParent(), "["))); } } else if (Token::simpleMatch(tok, "{") && getArgumentStart(tok) && !Token::simpleMatch(getArgumentStart(tok), ",") && getArgumentStart(tok)->valueType()) { const Token* vartok = getArgumentStart(tok); auto vts = getParentValueTypes(tok); auto it = std::find_if(vts.cbegin(), vts.cend(), [&](const ValueType& vt) { return vt.isTypeEqual(vartok->valueType()); }); if (it != vts.end()) return getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1); } return {{tok, std::move(errorPath)}}; } std::vector ValueFlow::getLifetimeTokens(const Token* tok, bool escape, ValueFlow::Value::ErrorPath errorPath) { return getLifetimeTokens(tok, escape, std::move(errorPath), [](const Token*) { return false; }); } bool ValueFlow::hasLifetimeToken(const Token* tok, const Token* lifetime) { bool result = false; getLifetimeTokens(tok, false, ValueFlow::Value::ErrorPath{}, [&](const Token* tok2) { result = tok2->exprId() == lifetime->exprId(); return result; }); return result; } static const Token* getLifetimeToken(const Token* tok, ValueFlow::Value::ErrorPath& errorPath, bool* addressOf = nullptr) { std::vector lts = ValueFlow::getLifetimeTokens(tok); if (lts.size() != 1) return nullptr; if (lts.front().inconclusive) return nullptr; if (addressOf) *addressOf = lts.front().addressOf; errorPath.insert(errorPath.end(), lts.front().errorPath.cbegin(), lts.front().errorPath.cend()); return lts.front().token; } const Variable* ValueFlow::getLifetimeVariable(const Token* tok, ValueFlow::Value::ErrorPath& errorPath, bool* addressOf) { const Token* tok2 = getLifetimeToken(tok, errorPath, addressOf); if (tok2 && tok2->variable()) return tok2->variable(); return nullptr; } const Variable* ValueFlow::getLifetimeVariable(const Token* tok) { ValueFlow::Value::ErrorPath errorPath; return getLifetimeVariable(tok, errorPath, nullptr); } static bool isNotLifetimeValue(const ValueFlow::Value& val) { return !val.isLifetimeValue(); } static bool isLifetimeOwned(const ValueType* vtParent) { if (vtParent->container) return !vtParent->container->view; return vtParent->type == ValueType::CONTAINER; } static bool isLifetimeOwned(const ValueType *vt, const ValueType *vtParent) { if (!vtParent) return false; if (isLifetimeOwned(vtParent)) return true; if (!vt) return false; // If converted from iterator to pointer then the iterator is most likely a pointer if (vtParent->pointer == 1 && vt->pointer == 0 && vt->type == ValueType::ITERATOR) return false; if (vt->type != ValueType::UNKNOWN_TYPE && vtParent->type != ValueType::UNKNOWN_TYPE) { if (vt->pointer != vtParent->pointer) return true; if (vt->type != vtParent->type) { if (vtParent->type == ValueType::RECORD) return true; if (isLifetimeOwned(vtParent)) return true; } } return false; } static bool isLifetimeBorrowed(const ValueType *vt, const ValueType *vtParent) { if (!vtParent) return false; if (!vt) return false; if (vt->pointer > 0 && vt->pointer == vtParent->pointer) return true; if (vtParent->container && vtParent->container->view) return true; if (vt->type != ValueType::UNKNOWN_TYPE && vtParent->type != ValueType::UNKNOWN_TYPE && vtParent->container == vt->container) { if (vtParent->pointer > vt->pointer) return true; if (vtParent->pointer < vt->pointer && vtParent->isIntegral()) return true; if (vtParent->str() == vt->str()) return true; } return false; } static const Token* skipCVRefs(const Token* tok, const Token* endTok) { while (tok != endTok && Token::Match(tok, "const|volatile|auto|&|&&")) tok = tok->next(); return tok; } static bool isNotEqual(std::pair x, std::pair y) { const Token* start1 = x.first; const Token* start2 = y.first; if (start1 == nullptr || start2 == nullptr) return false; while (start1 != x.second && start2 != y.second) { const Token* tok1 = skipCVRefs(start1, x.second); if (tok1 != start1) { start1 = tok1; continue; } const Token* tok2 = skipCVRefs(start2, y.second); if (tok2 != start2) { start2 = tok2; continue; } if (start1->str() != start2->str()) return true; start1 = start1->next(); start2 = start2->next(); } start1 = skipCVRefs(start1, x.second); start2 = skipCVRefs(start2, y.second); return !(start1 == x.second && start2 == y.second); } static bool isNotEqual(std::pair x, const std::string& y) { TokenList tokenList(nullptr); std::istringstream istr(y); tokenList.createTokens(istr); return isNotEqual(x, std::make_pair(tokenList.front(), tokenList.back())); } static bool isNotEqual(std::pair x, const ValueType* y) { if (y == nullptr) return false; if (y->originalTypeName.empty()) return false; return isNotEqual(x, y->originalTypeName); } static bool isDifferentType(const Token* src, const Token* dst) { const Type* t = Token::typeOf(src); const Type* parentT = Token::typeOf(dst); if (t && parentT) { if (t->classDef && parentT->classDef && t->classDef != parentT->classDef) return true; } else { std::pair decl = Token::typeDecl(src); std::pair parentdecl = Token::typeDecl(dst); if (isNotEqual(decl, parentdecl)) return true; if (isNotEqual(decl, dst->valueType())) return true; if (isNotEqual(parentdecl, src->valueType())) return true; } return false; } bool ValueFlow::isLifetimeBorrowed(const Token *tok, const Settings *settings) { if (!tok) return true; if (tok->str() == ",") return true; if (!tok->astParent()) return true; const Token* parent = nullptr; const ValueType* vt = tok->valueType(); std::vector vtParents = getParentValueTypes(tok, settings, &parent); for (const ValueType& vtParent : vtParents) { if (isLifetimeBorrowed(vt, &vtParent)) return true; if (isLifetimeOwned(vt, &vtParent)) return false; } if (parent) { if (isDifferentType(tok, parent)) return false; } return true; } static void valueFlowLifetimeFunction(Token *tok, TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings); static void valueFlowLifetimeConstructor(Token *tok, TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings); static bool isRangeForScope(const Scope* scope) { if (!scope) return false; if (scope->type != Scope::eFor) return false; if (!scope->bodyStart) return false; if (!Token::simpleMatch(scope->bodyStart->previous(), ") {")) return false; return Token::simpleMatch(scope->bodyStart->linkAt(-1)->astOperand2(), ":"); } static const Token* getEndOfVarScope(const Variable* var) { if (!var) return nullptr; const Scope* innerScope = var->scope(); const Scope* outerScope = innerScope; if (var->typeStartToken() && var->typeStartToken()->scope()) outerScope = var->typeStartToken()->scope(); if (!innerScope && outerScope) innerScope = outerScope; if (!innerScope || !outerScope) return nullptr; if (!innerScope->isExecutable()) return nullptr; // If the variable is defined in a for/while initializer then we want to // pick one token after the end so forward analysis can analyze the exit // conditions if (innerScope != outerScope && outerScope->isExecutable() && innerScope->isLoopScope() && !isRangeForScope(innerScope)) return innerScope->bodyEnd->next(); return innerScope->bodyEnd; } const Token* ValueFlow::getEndOfExprScope(const Token* tok, const Scope* defaultScope, bool smallest) { const Token* end = nullptr; bool local = false; visitAstNodes(tok, [&](const Token* child) { if (const Variable* var = child->variable()) { local |= var->isLocal(); if (var->isLocal() || var->isArgument()) { const Token* varEnd = getEndOfVarScope(var); if (!end || (smallest ? precedes(varEnd, end) : succeeds(varEnd, end))) end = varEnd; const Token* top = var->nameToken()->astTop(); if (top && Token::simpleMatch(top->tokAt(-1), "if (")) { // variable declared in if (...) const Token* elseTok = top->link()->linkAt(1); if (Token::simpleMatch(elseTok, "} else {") && tok->scope()->isNestedIn(elseTok->tokAt(2)->scope())) end = tok->scope()->bodyEnd; } } } return ChildrenToVisit::op1_and_op2; }); if (!end && defaultScope) end = defaultScope->bodyEnd; if (!end) { const Scope* scope = tok->scope(); if (scope) end = scope->bodyEnd; // If there is no local variables then pick the function scope if (!local) { while (scope && scope->isLocal()) scope = scope->nestedIn; if (scope && scope->isExecutable()) end = scope->bodyEnd; } } return end; } static void valueFlowForwardLifetime(Token * tok, TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings) { // Forward lifetimes to constructed variable if (Token::Match(tok->previous(), "%var% {|(") && isVariableDecl(tok->previous())) { std::list values = tok->values(); values.remove_if(&isNotLifetimeValue); valueFlowForward(nextAfterAstRightmostLeaf(tok), ValueFlow::getEndOfExprScope(tok), tok->previous(), values, tokenlist, settings); return; } Token *parent = tok->astParent(); while (parent && parent->str() == ",") parent = parent->astParent(); if (!parent) return; // Assignment if (parent->str() == "=" && (!parent->astParent() || Token::simpleMatch(parent->astParent(), ";"))) { // Rhs values.. if (!parent->astOperand2() || parent->astOperand2()->values().empty()) return; if (!ValueFlow::isLifetimeBorrowed(parent->astOperand2(), settings)) return; const Token* expr = getLHSVariableToken(parent); if (!expr) return; if (expr->exprId() == 0) return; const Token* endOfVarScope = ValueFlow::getEndOfExprScope(expr); // Only forward lifetime values std::list values = parent->astOperand2()->values(); values.remove_if(&isNotLifetimeValue); // Dont forward lifetimes that overlap values.remove_if([&](const ValueFlow::Value& value) { return findAstNode(value.tokvalue, [&](const Token* child) { return child->exprId() == expr->exprId(); }); }); // Skip RHS Token* nextExpression = nextAfterAstRightmostLeaf(parent); if (expr->exprId() > 0) { valueFlowForward(nextExpression, endOfVarScope->next(), expr, values, tokenlist, settings); for (ValueFlow::Value& val : values) { if (val.lifetimeKind == ValueFlow::Value::LifetimeKind::Address) val.lifetimeKind = ValueFlow::Value::LifetimeKind::SubObject; } // TODO: handle `[` if (Token::simpleMatch(parent->astOperand1(), ".")) { const Token* parentLifetime = getParentLifetime(tokenlist.isCPP(), parent->astOperand1()->astOperand2(), &settings->library); if (parentLifetime && parentLifetime->exprId() > 0) { valueFlowForward(nextExpression, endOfVarScope, parentLifetime, values, tokenlist, settings); } } } // Constructor } else if (Token::simpleMatch(parent, "{") && !isScopeBracket(parent)) { valueFlowLifetimeConstructor(parent, tokenlist, errorLogger, settings); valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings); // Function call } else if (Token::Match(parent->previous(), "%name% (")) { valueFlowLifetimeFunction(parent->previous(), tokenlist, errorLogger, settings); valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings); // Variable } else if (tok->variable() && tok->variable()->scope()) { const Variable *var = tok->variable(); const Token *endOfVarScope = var->scope()->bodyEnd; std::list values = tok->values(); Token *nextExpression = nextAfterAstRightmostLeaf(parent); // Only forward lifetime values values.remove_if(&isNotLifetimeValue); valueFlowForward(nextExpression, endOfVarScope, tok, values, tokenlist, settings); // Cast } else if (parent->isCast()) { std::list values = tok->values(); // Only forward lifetime values values.remove_if(&isNotLifetimeValue); for (ValueFlow::Value& value:values) setTokenValue(parent, std::move(value), settings); valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings); } } struct LifetimeStore { const Token* argtok{}; std::string message; ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object; ErrorPath errorPath; bool inconclusive{}; bool forward = true; struct Context { Token* tok{}; TokenList* tokenlist{}; ErrorLogger* errorLogger{}; const Settings* settings{}; }; LifetimeStore() = default; LifetimeStore(const Token* argtok, std::string message, ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object, bool inconclusive = false) : argtok(argtok), message(std::move(message)), type(type), inconclusive(inconclusive) {} template static void forEach(const std::vector& argtoks, const std::string& message, ValueFlow::Value::LifetimeKind type, F f) { std::map forwardToks; for (const Token* arg : argtoks) { LifetimeStore ls{arg, message, type}; Context c{}; ls.mContext = &c; ls.forward = false; f(ls); if (c.tok) forwardToks[c.tok] = c; } for (const auto& p : forwardToks) { const Context& c = p.second; valueFlowForwardLifetime(c.tok, *c.tokenlist, c.errorLogger, c.settings); } } static LifetimeStore fromFunctionArg(const Function * f, const Token *tok, const Variable *var, TokenList &tokenlist, const Settings* settings, ErrorLogger *errorLogger) { if (!var) return LifetimeStore{}; if (!var->isArgument()) return LifetimeStore{}; const int n = getArgumentPos(var, f); if (n < 0) return LifetimeStore{}; std::vector args = getArguments(tok); if (n >= args.size()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "Argument mismatch: Function '" + tok->str() + "' returning lifetime from argument index " + std::to_string(n) + " but only " + std::to_string(args.size()) + " arguments are available."); return LifetimeStore{}; } const Token *argtok2 = args[n]; return LifetimeStore{argtok2, "Passed to '" + tok->expressionString() + "'.", ValueFlow::Value::LifetimeKind::Object}; } template bool byRef(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings, Predicate pred, SourceLocation loc = SourceLocation::current()) const { if (!argtok) return false; bool update = false; for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(argtok)) { if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive) continue; ErrorPath er = errorPath; er.insert(er.end(), lt.errorPath.cbegin(), lt.errorPath.cend()); if (!lt.token) return false; if (!pred(lt.token)) return false; er.emplace_back(argtok, message); ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local; value.tokvalue = lt.token; value.errorPath = std::move(er); value.lifetimeKind = type; value.setInconclusive(lt.inconclusive || inconclusive); // Don't add the value a second time if (std::find(tok->values().cbegin(), tok->values().cend(), value) != tok->values().cend()) return false; if (settings->debugnormal) setSourceLocation(value, loc, tok); setTokenValue(tok, std::move(value), settings); update = true; } if (update && forward) forwardLifetime(tok, tokenlist, errorLogger, settings); return update; } bool byRef(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings, SourceLocation loc = SourceLocation::current()) const { return byRef( tok, tokenlist, errorLogger, settings, [](const Token*) { return true; }, loc); } template bool byVal(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings, Predicate pred, SourceLocation loc = SourceLocation::current()) const { if (!argtok) return false; bool update = false; if (argtok->values().empty()) { ErrorPath er; er.emplace_back(argtok, message); for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(argtok)) { if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive) continue; ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.tokvalue = lt.token; value.capturetok = argtok; value.errorPath = er; value.lifetimeKind = type; value.setInconclusive(inconclusive || lt.inconclusive); const Variable* var = lt.token->variable(); if (var && var->isArgument()) { value.lifetimeScope = ValueFlow::Value::LifetimeScope::Argument; } else { continue; } // Don't add the value a second time if (std::find(tok->values().cbegin(), tok->values().cend(), value) != tok->values().cend()) continue; if (settings->debugnormal) setSourceLocation(value, loc, tok); setTokenValue(tok, std::move(value), settings); update = true; } } for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok3 = v.tokvalue; for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(tok3)) { if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive) continue; ErrorPath er = v.errorPath; er.insert(er.end(), lt.errorPath.cbegin(), lt.errorPath.cend()); if (!lt.token) return false; if (!pred(lt.token)) return false; er.emplace_back(argtok, message); er.insert(er.end(), errorPath.cbegin(), errorPath.cend()); ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = v.lifetimeScope; value.path = v.path; value.tokvalue = lt.token; value.capturetok = argtok; value.errorPath = std::move(er); value.lifetimeKind = type; value.setInconclusive(lt.inconclusive || v.isInconclusive() || inconclusive); // Don't add the value a second time if (std::find(tok->values().cbegin(), tok->values().cend(), value) != tok->values().cend()) continue; if (settings->debugnormal) setSourceLocation(value, loc, tok); setTokenValue(tok, std::move(value), settings); update = true; } } if (update && forward) forwardLifetime(tok, tokenlist, errorLogger, settings); return update; } bool byVal(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings, SourceLocation loc = SourceLocation::current()) const { return byVal( tok, tokenlist, errorLogger, settings, [](const Token*) { return true; }, loc); } template bool byDerefCopy(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings, Predicate pred, SourceLocation loc = SourceLocation::current()) const { bool update = false; if (!settings->certainty.isEnabled(Certainty::inconclusive) && inconclusive) return update; if (!argtok) return update; if (!tok) return update; for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok2 = v.tokvalue; ErrorPath er = v.errorPath; const Variable *var = ValueFlow::getLifetimeVariable(tok2, er); // TODO: the inserted data is never used er.insert(er.end(), errorPath.cbegin(), errorPath.cend()); if (!var) continue; const Token * const varDeclEndToken = var->declEndToken(); for (const Token *tok3 = tok; tok3 && tok3 != varDeclEndToken; tok3 = tok3->previous()) { if (tok3->varId() == var->declarationId()) { update |= LifetimeStore{tok3, message, type, inconclusive} .byVal(tok, tokenlist, errorLogger, settings, pred, loc); break; } } } return update; } bool byDerefCopy(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings, SourceLocation loc = SourceLocation::current()) const { return byDerefCopy( tok, tokenlist, errorLogger, settings, [](const Token*) { return true; }, loc); } private: Context* mContext{}; void forwardLifetime(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) const { if (mContext) { mContext->tok = tok; mContext->tokenlist = &tokenlist; mContext->errorLogger = errorLogger; mContext->settings = settings; } valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } }; static bool hasBorrowingVariables(const std::list& vars, const std::vector& args, int depth = 10) { if (depth < 0) return true; return std::any_of(vars.cbegin(), vars.cend(), [&](const Variable& var) { if (const ValueType* vt = var.valueType()) { if (vt->pointer > 0 && std::none_of(args.begin(), args.end(), [vt](const Token* arg) { return arg->valueType() && arg->valueType()->type == vt->type; })) return false; if (vt->pointer > 0) return true; if (vt->reference != Reference::None) return true; if (vt->isPrimitive()) return false; if (vt->isEnum()) return false; // TODO: Check container inner type if (vt->type == ValueType::CONTAINER && vt->container) return vt->container->view; if (vt->typeScope) return hasBorrowingVariables(vt->typeScope->varlist, args, depth - 1); } return true; }); } static void valueFlowLifetimeUserConstructor(Token* tok, const Function* constructor, const std::string& name, std::vector args, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) { if (!constructor) return; std::unordered_map argToParam; for (std::size_t i = 0; i < args.size(); i++) argToParam[args[i]] = constructor->getArgumentVar(i); if (const Token* initList = constructor->constructorMemberInitialization()) { std::unordered_map paramCapture; for (const Token* tok2 : astFlatten(initList->astOperand2(), ",")) { if (!Token::simpleMatch(tok2, "(")) continue; if (!tok2->astOperand1()) continue; if (!tok2->astOperand2()) continue; const Variable* var = tok2->astOperand1()->variable(); const Token* expr = tok2->astOperand2(); if (!var) continue; if (!ValueFlow::isLifetimeBorrowed(expr, settings)) continue; const Variable* argvar = ValueFlow::getLifetimeVariable(expr); if (var->isReference() || var->isRValueReference()) { if (argvar && argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) { paramCapture[argvar] = LifetimeCapture::ByReference; } } else { bool found = false; for (const ValueFlow::Value& v : expr->values()) { if (!v.isLifetimeValue()) continue; if (v.path > 0) continue; if (!v.tokvalue) continue; const Variable* lifeVar = v.tokvalue->variable(); if (!lifeVar) continue; LifetimeCapture c = LifetimeCapture::Undefined; if (!v.isArgumentLifetimeValue() && (lifeVar->isReference() || lifeVar->isRValueReference())) c = LifetimeCapture::ByReference; else if (v.isArgumentLifetimeValue()) c = LifetimeCapture::ByValue; if (c != LifetimeCapture::Undefined) { paramCapture[lifeVar] = c; found = true; } } if (!found && argvar && argvar->isArgument()) paramCapture[argvar] = LifetimeCapture::ByValue; } } // TODO: Use SubExpressionAnalyzer for members LifetimeStore::forEach(args, "Passed to constructor of '" + name + "'.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { const Variable* paramVar = argToParam.at(ls.argtok); if (paramCapture.count(paramVar) == 0) return; const LifetimeCapture c = paramCapture.at(paramVar); if (c == LifetimeCapture::ByReference) ls.byRef(tok, tokenlist, errorLogger, settings); else ls.byVal(tok, tokenlist, errorLogger, settings); }); } else if (hasBorrowingVariables(constructor->nestedIn->varlist, args)) { LifetimeStore::forEach(args, "Passed to constructor of '" + name + "'.", ValueFlow::Value::LifetimeKind::SubObject, [&](LifetimeStore& ls) { ls.inconclusive = true; const Variable* var = argToParam.at(ls.argtok); if (var && !var->isConst() && var->isReference()) ls.byRef(tok, tokenlist, errorLogger, settings); else ls.byVal(tok, tokenlist, errorLogger, settings); }); } } static void valueFlowLifetimeFunction(Token *tok, TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings) { if (!Token::Match(tok, "%name% (")) return; Token* memtok = nullptr; if (Token::Match(tok->astParent(), ". %name% (") && astIsRHS(tok)) memtok = tok->astParent()->astOperand1(); const int returnContainer = settings->library.returnValueContainer(tok); if (returnContainer >= 0) { std::vector args = getArguments(tok); for (int argnr = 1; argnr <= args.size(); ++argnr) { const Library::ArgumentChecks::IteratorInfo *i = settings->library.getArgIteratorInfo(tok, argnr); if (!i) continue; if (i->container != returnContainer) continue; const Token * const argTok = args[argnr - 1]; bool forward = false; for (ValueFlow::Value val : argTok->values()) { if (!val.isLifetimeValue()) continue; val.errorPath.emplace_back(argTok, "Passed to '" + tok->str() + "'."); setTokenValue(tok->next(), std::move(val), settings); forward = true; } // Check if lifetime is available to avoid adding the lifetime twice if (forward) { valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); break; } } } else if (Token::Match(tok->tokAt(-2), "std :: ref|cref|tie|front_inserter|back_inserter")) { for (const Token *argtok : getArguments(tok)) { LifetimeStore{argtok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}.byRef( tok->next(), tokenlist, errorLogger, settings); } } else if (Token::Match(tok->tokAt(-2), "std :: make_tuple|tuple_cat|make_pair|make_reverse_iterator|next|prev|move|bind")) { for (const Token *argtok : getArguments(tok)) { LifetimeStore{argtok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}.byVal( tok->next(), tokenlist, errorLogger, settings); } } else if (memtok && Token::Match(tok->astParent(), ". push_back|push_front|insert|push|assign") && astIsContainer(memtok)) { std::vector args = getArguments(tok); const std::size_t n = args.size(); if (n > 1 && Token::typeStr(args[n - 2]) == Token::typeStr(args[n - 1]) && (((astIsIterator(args[n - 2]) && astIsIterator(args[n - 1])) || (astIsPointer(args[n - 2]) && astIsPointer(args[n - 1]))))) { LifetimeStore{ args.back(), "Added to container '" + memtok->str() + "'.", ValueFlow::Value::LifetimeKind::Object} .byDerefCopy(memtok, tokenlist, errorLogger, settings); } else if (!args.empty() && ValueFlow::isLifetimeBorrowed(args.back(), settings)) { LifetimeStore{ args.back(), "Added to container '" + memtok->str() + "'.", ValueFlow::Value::LifetimeKind::Object} .byVal(memtok, tokenlist, errorLogger, settings); } } else if (tok->function()) { const Function *f = tok->function(); if (f->isConstructor()) { valueFlowLifetimeUserConstructor(tok->next(), f, tok->str(), getArguments(tok), tokenlist, errorLogger, settings); return; } if (Function::returnsReference(f)) return; std::vector returns = Function::findReturns(f); const bool inconclusive = returns.size() > 1; bool update = false; for (const Token* returnTok : returns) { if (returnTok == tok) continue; const Variable *returnVar = ValueFlow::getLifetimeVariable(returnTok); if (returnVar && returnVar->isArgument() && (returnVar->isConst() || !isVariableChanged(returnVar, settings, tokenlist.isCPP()))) { LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, returnVar, tokenlist, settings, errorLogger); ls.inconclusive = inconclusive; ls.forward = false; update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings); } for (const ValueFlow::Value &v : returnTok->values()) { if (!v.isLifetimeValue()) continue; if (!v.tokvalue) continue; if (memtok && (contains({ValueFlow::Value::LifetimeScope::ThisPointer, ValueFlow::Value::LifetimeScope::ThisValue}, v.lifetimeScope) || exprDependsOnThis(v.tokvalue))) { LifetimeStore ls = LifetimeStore{memtok, "Passed to member function '" + tok->expressionString() + "'.", ValueFlow::Value::LifetimeKind::Object}; ls.inconclusive = inconclusive; ls.forward = false; ls.errorPath = v.errorPath; ls.errorPath.emplace_front(returnTok, "Return " + lifetimeType(returnTok, &v) + "."); int thisIndirect = v.lifetimeScope == ValueFlow::Value::LifetimeScope::ThisValue ? 0 : 1; if (derefShared(memtok->astParent())) thisIndirect--; if (thisIndirect == -1) update |= ls.byDerefCopy(tok->next(), tokenlist, errorLogger, settings); else if (thisIndirect == 0) update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings); else if (thisIndirect == 1) update |= ls.byRef(tok->next(), tokenlist, errorLogger, settings); continue; } const Variable *var = v.tokvalue->variable(); LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, var, tokenlist, settings, errorLogger); if (!ls.argtok) continue; ls.forward = false; ls.inconclusive = inconclusive; ls.errorPath = v.errorPath; ls.errorPath.emplace_front(returnTok, "Return " + lifetimeType(returnTok, &v) + "."); if (!v.isArgumentLifetimeValue() && (var->isReference() || var->isRValueReference())) { update |= ls.byRef(tok->next(), tokenlist, errorLogger, settings); } else if (v.isArgumentLifetimeValue()) { update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings); } } } if (update) valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings); } else if (tok->valueType()) { // TODO: Propagate lifetimes with library functions if (settings->library.getFunction(tok->previous())) return; // Assume constructing the valueType valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings); valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings); } else { const std::string& retVal = settings->library.returnValue(tok); if (startsWith(retVal, "arg")) { std::size_t iArg{}; try { iArg = strToInt(retVal.substr(3)); } catch (...) { return; } std::vector args = getArguments(tok); if (iArg > 0 && iArg <= args.size()) { const Token* varTok = args[iArg - 1]; if (varTok->variable() && varTok->variable()->isLocal()) LifetimeStore{ varTok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Address }.byRef( tok->next(), tokenlist, errorLogger, settings); } } } } static bool isScope(const Token* tok) { if (!tok) return false; if (!Token::simpleMatch(tok, "{")) return false; const Scope* scope = tok->scope(); if (!scope) return false; if (!scope->bodyStart) return false; return scope->bodyStart == tok; } static const Function* findConstructor(const Scope* scope, const Token* tok, const std::vector& args) { if (!tok) return nullptr; const Function* f = tok->function(); if (!f && tok->astOperand1()) f = tok->astOperand1()->function(); // Search for a constructor if (!f || !f->isConstructor()) { f = nullptr; std::vector candidates; for (const Function& function : scope->functionList) { if (function.minArgCount() > args.size()) continue; if (!function.isConstructor()) continue; candidates.push_back(&function); } // TODO: Narrow the candidates if (candidates.size() == 1) f = candidates.front(); } if (!f) return nullptr; return f; } static void valueFlowLifetimeClassConstructor(Token* tok, const Type* t, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) { if (!Token::Match(tok, "(|{")) return; if (isScope(tok)) return; if (!t) { if (tok->valueType() && tok->valueType()->type != ValueType::RECORD) return; if (tok->str() != "{" && !Token::Match(tok->previous(), "%var% (") && !isVariableDecl(tok->previous())) return; // If the type is unknown then assume it captures by value in the // constructor, but make each lifetime inconclusive std::vector args = getArguments(tok); LifetimeStore::forEach(args, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::SubObject, [&](LifetimeStore& ls) { ls.inconclusive = true; ls.byVal(tok, tokenlist, errorLogger, settings); }); return; } const Scope* scope = t->classScope; if (!scope) return; // Aggregate constructor if (t->derivedFrom.empty() && (t->isClassType() || t->isStructType())) { std::vector args = getArguments(tok); if (scope->numConstructors == 0) { auto it = scope->varlist.cbegin(); LifetimeStore::forEach( args, "Passed to constructor of '" + t->name() + "'.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { // Skip static variable it = std::find_if(it, scope->varlist.cend(), [](const Variable& var) { return !var.isStatic(); }); if (it == scope->varlist.cend()) return; const Variable& var = *it; if (var.isReference() || var.isRValueReference()) { ls.byRef(tok, tokenlist, errorLogger, settings); } else if (ValueFlow::isLifetimeBorrowed(ls.argtok, settings)) { ls.byVal(tok, tokenlist, errorLogger, settings); } it++; }); } else { const Function* constructor = findConstructor(scope, tok, args); valueFlowLifetimeUserConstructor(tok, constructor, t->name(), args, tokenlist, errorLogger, settings); } } } static void valueFlowLifetimeConstructor(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) { if (!Token::Match(tok, "(|{")) return; if (isScope(tok)) return; std::vector vts; if (tok->valueType()) { vts = {*tok->valueType()}; } else if (Token::Match(tok->previous(), "%var% {|(") && isVariableDecl(tok->previous()) && tok->previous()->valueType()) { vts = {*tok->previous()->valueType()}; } else if (Token::simpleMatch(tok, "{") && !Token::Match(tok->previous(), "%name%")) { vts = getParentValueTypes(tok, settings); } for (const ValueType& vt : vts) { if (vt.pointer > 0) { std::vector args = getArguments(tok); LifetimeStore::forEach(args, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { ls.byVal(tok, tokenlist, errorLogger, settings); }); } else if (vt.container && vt.type == ValueType::CONTAINER) { std::vector args = getArguments(tok); if (args.size() == 1 && vt.container->view && astIsContainerOwned(args.front())) { LifetimeStore{args.front(), "Passed to container view.", ValueFlow::Value::LifetimeKind::SubObject} .byRef(tok, tokenlist, errorLogger, settings); } else if (args.size() == 2 && astIsIterator(args[0]) && astIsIterator(args[1])) { LifetimeStore::forEach( args, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { ls.byDerefCopy(tok, tokenlist, errorLogger, settings); }); } else if (vt.container->hasInitializerListConstructor) { LifetimeStore::forEach(args, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { ls.byVal(tok, tokenlist, errorLogger, settings); }); } } else { const Type* t = nullptr; if (vt.typeScope && vt.typeScope->definedType) t = vt.typeScope->definedType; else t = Token::typeOf(tok->previous()); valueFlowLifetimeClassConstructor(tok, t, tokenlist, errorLogger, settings); } } } struct Lambda { explicit Lambda(const Token* tok) { if (!Token::simpleMatch(tok, "[") || !tok->link()) return; capture = tok; if (Token::simpleMatch(capture->link(), "] (")) { arguments = capture->link()->next(); } const Token * afterArguments = arguments ? arguments->link()->next() : capture->link()->next(); if (afterArguments && afterArguments->originalName() == "->") { returnTok = afterArguments->next(); bodyTok = Token::findsimplematch(returnTok, "{"); } else if (Token::simpleMatch(afterArguments, "{")) { bodyTok = afterArguments; } for (const Token* c:getCaptures()) { if (Token::Match(c, "this !!.")) { explicitCaptures[c->variable()] = std::make_pair(c, LifetimeCapture::ByReference); } else if (Token::simpleMatch(c, "* this")) { explicitCaptures[c->next()->variable()] = std::make_pair(c->next(), LifetimeCapture::ByValue); } else if (c->variable()) { explicitCaptures[c->variable()] = std::make_pair(c, LifetimeCapture::ByValue); } else if (c->isUnaryOp("&") && Token::Match(c->astOperand1(), "%var%")) { explicitCaptures[c->astOperand1()->variable()] = std::make_pair(c->astOperand1(), LifetimeCapture::ByReference); } else { const std::string& s = c->expressionString(); if (s == "=") implicitCapture = LifetimeCapture::ByValue; else if (s == "&") implicitCapture = LifetimeCapture::ByReference; } } } const Token* capture{}; const Token* arguments{}; const Token* returnTok{}; const Token* bodyTok{}; std::unordered_map> explicitCaptures; LifetimeCapture implicitCapture = LifetimeCapture::Undefined; std::vector getCaptures() const { return getArguments(capture); } bool isLambda() const { return capture && bodyTok; } }; static bool isDecayedPointer(const Token *tok) { if (!tok) return false; if (!tok->astParent()) return false; if (astIsPointer(tok->astParent()) && !Token::simpleMatch(tok->astParent(), "return")) return true; if (tok->astParent()->isConstOp()) return true; if (!Token::simpleMatch(tok->astParent(), "return")) return false; return astIsPointer(tok->astParent()); } static bool isConvertedToView(const Token* tok, const Settings* settings) { std::vector vtParents = getParentValueTypes(tok, settings); return std::any_of(vtParents.cbegin(), vtParents.cend(), [&](const ValueType& vt) { if (!vt.container) return false; return vt.container->view; }); } static bool isContainerOfPointers(const Token* tok, const Settings* settings) { if (!tok) { return true; } ValueType vt = ValueType::parseDecl(tok, *settings); return vt.pointer > 0; } static void valueFlowLifetime(TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->scope()) continue; if (tok->scope()->type == Scope::eGlobal) continue; Lambda lam(tok); // Lambdas if (lam.isLambda()) { const Scope * bodyScope = lam.bodyTok->scope(); std::set scopes; // Avoid capturing a variable twice std::set varids; bool capturedThis = false; auto isImplicitCapturingVariable = [&](const Token *varTok) { const Variable *var = varTok->variable(); if (!var) return false; if (varids.count(var->declarationId()) > 0) return false; if (!var->isLocal() && !var->isArgument()) return false; const Scope *scope = var->scope(); if (!scope) return false; if (scopes.count(scope) > 0) return false; if (scope->isNestedIn(bodyScope)) return false; scopes.insert(scope); varids.insert(var->declarationId()); return true; }; bool update = false; auto captureVariable = [&](const Token* tok2, LifetimeCapture c, const std::function &pred) { if (varids.count(tok->varId()) > 0) return; if (c == LifetimeCapture::ByReference) { LifetimeStore ls{ tok2, "Lambda captures variable by reference here.", ValueFlow::Value::LifetimeKind::Lambda}; ls.forward = false; update |= ls.byRef(tok, tokenlist, errorLogger, settings, pred); } else if (c == LifetimeCapture::ByValue) { LifetimeStore ls{ tok2, "Lambda captures variable by value here.", ValueFlow::Value::LifetimeKind::Lambda}; ls.forward = false; update |= ls.byVal(tok, tokenlist, errorLogger, settings, pred); pred(tok2); } }; auto captureThisVariable = [&](const Token* tok2, LifetimeCapture c) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; if (c == LifetimeCapture::ByReference) value.lifetimeScope = ValueFlow::Value::LifetimeScope::ThisPointer; else if (c == LifetimeCapture::ByValue) value.lifetimeScope = ValueFlow::Value::LifetimeScope::ThisValue; value.tokvalue = tok2; value.errorPath.emplace_back(tok2, "Lambda captures the 'this' variable here."); value.lifetimeKind = ValueFlow::Value::LifetimeKind::Lambda; capturedThis = true; // Don't add the value a second time if (std::find(tok->values().cbegin(), tok->values().cend(), value) != tok->values().cend()) return; setTokenValue(tok, std::move(value), settings); update |= true; }; // Handle explicit capture for (const auto& p:lam.explicitCaptures) { const Variable* var = p.first; const Token* tok2 = p.second.first; const LifetimeCapture c = p.second.second; if (Token::Match(tok2, "this !!.")) { captureThisVariable(tok2, c); } else if (var) { captureVariable(tok2, c, [](const Token*) { return true; }); varids.insert(var->declarationId()); } } auto isImplicitCapturingThis = [&](const Token* tok2) { if (capturedThis) return false; if (Token::simpleMatch(tok2, "this")) return true; if (tok2->variable()) { if (Token::simpleMatch(tok2->previous(), ".")) return false; const Variable* var = tok2->variable(); if (var->isLocal()) return false; if (var->isArgument()) return false; return exprDependsOnThis(tok2); } if (Token::simpleMatch(tok2, "(")) return exprDependsOnThis(tok2); return false; }; for (const Token * tok2 = lam.bodyTok; tok2 != lam.bodyTok->link(); tok2 = tok2->next()) { if (isImplicitCapturingThis(tok2)) { captureThisVariable(tok2, LifetimeCapture::ByReference); } else if (tok2->variable()) { captureVariable(tok2, lam.implicitCapture, isImplicitCapturingVariable); } } if (update) valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } // address of else if (tok->isUnaryOp("&")) { for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(tok->astOperand1())) { if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive) continue; ErrorPath errorPath = lt.errorPath; errorPath.emplace_back(tok, "Address of variable taken here."); ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local; value.tokvalue = lt.token; value.errorPath = std::move(errorPath); if (lt.addressOf || astIsPointer(lt.token) || !Token::Match(lt.token->astParent(), ".|[")) value.lifetimeKind = ValueFlow::Value::LifetimeKind::Address; value.setInconclusive(lt.inconclusive); setTokenValue(tok, std::move(value), settings); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } // Converting to container view else if (astIsContainerOwned(tok) && isConvertedToView(tok, settings)) { LifetimeStore ls = LifetimeStore{tok, "Converted to container view", ValueFlow::Value::LifetimeKind::SubObject}; ls.byRef(tok, tokenlist, errorLogger, settings); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } // container lifetimes else if (astIsContainer(tok)) { Token * parent = astParentSkipParens(tok); if (!parent) continue; if (!Token::Match(parent, ". %name% (") && !Token::Match(parent->previous(), "%name% (")) continue; // Skip if its a free function that doesnt yield an iterator to the container if (Token::Match(parent->previous(), "%name% (") && !contains({Library::Container::Yield::START_ITERATOR, Library::Container::Yield::END_ITERATOR}, astFunctionYield(parent->previous(), settings))) continue; ValueFlow::Value master; master.valueType = ValueFlow::Value::ValueType::LIFETIME; master.lifetimeScope = ValueFlow::Value::LifetimeScope::Local; if (astIsIterator(parent->tokAt(2))) { master.errorPath.emplace_back(parent->tokAt(2), "Iterator to container is created here."); master.lifetimeKind = ValueFlow::Value::LifetimeKind::Iterator; } else if (astIsIterator(parent) && Token::Match(parent->previous(), "%name% (") && contains({Library::Container::Yield::START_ITERATOR, Library::Container::Yield::END_ITERATOR}, astFunctionYield(parent->previous(), settings))) { master.errorPath.emplace_back(parent, "Iterator to container is created here."); master.lifetimeKind = ValueFlow::Value::LifetimeKind::Iterator; } else if ((astIsPointer(parent->tokAt(2)) && !isContainerOfPointers(tok->valueType()->containerTypeToken, settings)) || Token::Match(parent->next(), "data|c_str")) { master.errorPath.emplace_back(parent->tokAt(2), "Pointer to container is created here."); master.lifetimeKind = ValueFlow::Value::LifetimeKind::Object; } else { continue; } std::vector toks; if (tok->isUnaryOp("*") || parent->originalName() == "->") { for (const ValueFlow::Value& v : tok->values()) { if (!v.isLocalLifetimeValue()) continue; if (v.lifetimeKind != ValueFlow::Value::LifetimeKind::Address) continue; if (!v.tokvalue) continue; toks.push_back(v.tokvalue); } } else if (astIsContainerView(tok)) { for (const ValueFlow::Value& v : tok->values()) { if (!v.isLocalLifetimeValue()) continue; if (!v.tokvalue) continue; if (!astIsContainerOwned(v.tokvalue)) continue; toks.push_back(v.tokvalue); } } else { toks = {tok}; } for (const Token* tok2 : toks) { for (const ReferenceToken& rt : followAllReferences(tok2, false)) { ValueFlow::Value value = master; value.tokvalue = rt.token; value.errorPath.insert(value.errorPath.begin(), rt.errors.cbegin(), rt.errors.cend()); if (Token::simpleMatch(parent, "(")) setTokenValue(parent, value, settings); else setTokenValue(parent->tokAt(2), value, settings); if (!rt.token->variable()) { LifetimeStore ls = LifetimeStore{ rt.token, master.errorPath.back().second, ValueFlow::Value::LifetimeKind::Object}; ls.byRef(parent->tokAt(2), tokenlist, errorLogger, settings); } } } valueFlowForwardLifetime(parent->tokAt(2), tokenlist, errorLogger, settings); } // Check constructors else if (Token::Match(tok, "=|return|%name%|{|,|> {") && !isScope(tok->next())) { valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings); } // Check function calls else if (Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->next()->link(), ") {")) { valueFlowLifetimeFunction(tok, tokenlist, errorLogger, settings); } // Unique pointer lifetimes else if (astIsUniqueSmartPointer(tok) && astIsLHS(tok) && Token::simpleMatch(tok->astParent(), ". get ( )")) { Token* ptok = tok->astParent()->tokAt(2); ErrorPath errorPath = {{ptok, "Raw pointer to smart pointer created here."}}; ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local; value.lifetimeKind = ValueFlow::Value::LifetimeKind::SubObject; value.tokvalue = tok; value.errorPath = errorPath; setTokenValue(ptok, std::move(value), settings); valueFlowForwardLifetime(ptok, tokenlist, errorLogger, settings); } // Check variables else if (tok->variable()) { ErrorPath errorPath; const Variable * var = ValueFlow::getLifetimeVariable(tok, errorPath); if (!var) continue; if (var->nameToken() == tok) continue; if (var->isArray() && !var->isStlType() && !var->isArgument() && isDecayedPointer(tok)) { errorPath.emplace_back(tok, "Array decayed to pointer here."); ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local; value.tokvalue = var->nameToken(); value.errorPath = errorPath; setTokenValue(tok, std::move(value), settings); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } // Forward any lifetimes else if (std::any_of(tok->values().cbegin(), tok->values().cend(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) { valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } } static bool isStdMoveOrStdForwarded(Token * tok, ValueFlow::Value::MoveKind * moveKind, Token ** varTok = nullptr) { if (tok->str() != "std") return false; ValueFlow::Value::MoveKind kind = ValueFlow::Value::MoveKind::NonMovedVariable; Token * variableToken = nullptr; if (Token::Match(tok, "std :: move ( %var% )")) { variableToken = tok->tokAt(4); kind = ValueFlow::Value::MoveKind::MovedVariable; } else if (Token::simpleMatch(tok, "std :: forward <")) { Token * const leftAngle = tok->tokAt(3); Token * rightAngle = leftAngle->link(); if (Token::Match(rightAngle, "> ( %var% )")) { variableToken = rightAngle->tokAt(2); kind = ValueFlow::Value::MoveKind::ForwardedVariable; } } if (!variableToken) return false; if (variableToken->strAt(2) == ".") // Only partially moved return false; if (variableToken->valueType() && variableToken->valueType()->type >= ValueType::Type::VOID) return false; if (moveKind != nullptr) *moveKind = kind; if (varTok != nullptr) *varTok = variableToken; return true; } static bool isOpenParenthesisMemberFunctionCallOfVarId(const Token * openParenthesisToken, nonneg int varId) { const Token * varTok = openParenthesisToken->tokAt(-3); return Token::Match(varTok, "%varid% . %name% (", varId) && varTok->next()->originalName().empty(); } static Token* findOpenParentesisOfMove(Token* moveVarTok) { Token* tok = moveVarTok; while (tok && tok->str() != "(") tok = tok->previous(); return tok; } static Token* findEndOfFunctionCallForParameter(Token* parameterToken) { if (!parameterToken) return nullptr; Token* parent = parameterToken->astParent(); while (parent && !parent->isOp() && !Token::Match(parent, "[({]")) parent = parent->astParent(); if (!parent) return nullptr; return nextAfterAstRightmostLeaf(parent); } static void valueFlowAfterMove(TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings) { if (!tokenlist.isCPP() || settings->standards.cpp < Standards::CPP11) return; for (const Scope * scope : symboldatabase.functionScopes) { if (!scope) continue; const Token * start = scope->bodyStart; if (scope->function) { const Token * memberInitializationTok = scope->function->constructorMemberInitialization(); if (memberInitializationTok) start = memberInitializationTok; } for (Token* tok = const_cast(start); tok != scope->bodyEnd; tok = tok->next()) { Token * varTok; if (Token::Match(tok, "%var% . reset|clear (") && tok->next()->originalName().empty()) { varTok = tok; const Variable *var = tok->variable(); if (!var || (!var->isLocal() && !var->isArgument())) continue; ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::MOVED; value.moveKind = ValueFlow::Value::MoveKind::NonMovedVariable; value.errorPath.emplace_back(tok, "Calling " + tok->next()->expressionString() + " makes " + tok->str() + " 'non-moved'"); value.setKnown(); setTokenValue(tok, value, settings); if (var->scope()) { const Token* const endOfVarScope = var->scope()->bodyEnd; valueFlowForward(tok->next(), endOfVarScope, tok, std::move(value), tokenlist, settings); } continue; } ValueFlow::Value::MoveKind moveKind; if (!isStdMoveOrStdForwarded(tok, &moveKind, &varTok)) continue; const nonneg int varId = varTok->varId(); // x is not MOVED after assignment if code is: x = ... std::move(x) .. ; const Token *parent = tok->astParent(); while (parent && parent->str() != "=" && parent->str() != "return" && !(parent->str() == "(" && isOpenParenthesisMemberFunctionCallOfVarId(parent, varId))) parent = parent->astParent(); if (parent && (parent->str() == "return" || // MOVED in return statement parent->str() == "(")) // MOVED in self assignment, isOpenParenthesisMemberFunctionCallOfVarId == true continue; if (parent && parent->astOperand1() && parent->astOperand1()->varId() == varId) continue; const Token* const endOfVarScope = ValueFlow::getEndOfExprScope(varTok); Token* openParentesisOfMove = findOpenParentesisOfMove(varTok); Token* endOfFunctionCall = findEndOfFunctionCallForParameter(openParentesisOfMove); if (endOfFunctionCall) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::MOVED; value.moveKind = moveKind; if (moveKind == ValueFlow::Value::MoveKind::MovedVariable) value.errorPath.emplace_back(tok, "Calling std::move(" + varTok->str() + ")"); else // if (moveKind == ValueFlow::Value::ForwardedVariable) value.errorPath.emplace_back(tok, "Calling std::forward(" + varTok->str() + ")"); value.setKnown(); valueFlowForward(endOfFunctionCall, endOfVarScope, varTok, std::move(value), tokenlist, settings); } } } } static const Token* findIncompleteVar(const Token* start, const Token* end) { for (const Token* tok = start; tok != end; tok = tok->next()) { if (tok->isIncompleteVar()) return tok; } return nullptr; } static ValueFlow::Value makeConditionValue(long long val, const Token* condTok, bool assume, bool impossible = false, const Settings* settings = nullptr, SourceLocation loc = SourceLocation::current()) { ValueFlow::Value v(val); v.setKnown(); if (impossible) { v.intvalue = !v.intvalue; v.setImpossible(); } v.condition = condTok; if (assume) v.errorPath.emplace_back(condTok, "Assuming condition '" + condTok->expressionString() + "' is true"); else v.errorPath.emplace_back(condTok, "Assuming condition '" + condTok->expressionString() + "' is false"); if (settings && settings->debugnormal) setSourceLocation(v, loc, condTok); return v; } static std::vector getConditions(const Token* tok, const char* op) { std::vector conds = {tok}; if (tok->str() == op) { std::vector args = astFlatten(tok, op); std::copy_if(args.cbegin(), args.cend(), std::back_inserter(conds), [&](const Token* tok2) { if (tok2->exprId() == 0) return false; if (tok2->hasKnownIntValue()) return false; if (Token::Match(tok2, "%var%|.") && !astIsBool(tok2)) return false; return true; }); } return conds; } static bool isBreakOrContinueScope(const Token* endToken) { if (!Token::simpleMatch(endToken, "}")) return false; return Token::Match(endToken->tokAt(-2), "break|continue ;"); } static const Scope* getLoopScope(const Token* tok) { if (!tok) return nullptr; const Scope* scope = tok->scope(); while (scope && scope->type != Scope::eWhile && scope->type != Scope::eFor && scope->type != Scope::eDo) scope = scope->nestedIn; return scope; } // static void valueFlowConditionExpressions(TokenList &tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger *errorLogger, const Settings &settings) { for (const Scope * scope : symboldatabase.functionScopes) { if (const Token* incompleteTok = findIncompleteVar(scope->bodyStart, scope->bodyEnd)) { if (settings.debugwarnings) bailoutIncompleteVar(tokenlist, errorLogger, incompleteTok, "Skipping function due to incomplete variable " + incompleteTok->str()); break; } for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (!Token::simpleMatch(tok, "if (")) continue; Token* parenTok = tok->next(); if (!Token::simpleMatch(parenTok->link(), ") {")) continue; Token * blockTok = parenTok->link()->tokAt(1); const Token* condTok = parenTok->astOperand2(); if (condTok->exprId() == 0) continue; if (condTok->hasKnownIntValue()) continue; if (!isConstExpression(condTok, settings.library, tokenlist.isCPP())) continue; const bool is1 = (condTok->isComparisonOp() || condTok->tokType() == Token::eLogicalOp || astIsBool(condTok)); Token* startTok = blockTok; // Inner condition { for (const Token* condTok2 : getConditions(condTok, "&&")) { if (is1) { const bool isBool = astIsBool(condTok2) || Token::Match(condTok2, "%comp%|%oror%|&&"); SameExpressionAnalyzer a1(condTok2, makeConditionValue(1, condTok2, /*assume*/ true, !isBool), tokenlist, &settings); // don't set '1' for non-boolean expressions valueFlowGenericForward(startTok, startTok->link(), a1, settings); } OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(0, condTok2, true), tokenlist, &settings); valueFlowGenericForward(startTok, startTok->link(), a2, settings); } } std::vector conds = getConditions(condTok, "||"); // Check else block if (Token::simpleMatch(startTok->link(), "} else {")) { startTok = startTok->link()->tokAt(2); for (const Token* condTok2:conds) { SameExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist, &settings); valueFlowGenericForward(startTok, startTok->link(), a1, settings); if (is1) { OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist, &settings); valueFlowGenericForward(startTok, startTok->link(), a2, settings); } } } // Check if the block terminates early if (isEscapeScope(blockTok, &settings)) { const Scope* scope2 = scope; // If escaping a loop then only use the loop scope if (isBreakOrContinueScope(blockTok->link())) { scope2 = getLoopScope(blockTok->link()); if (!scope2) continue; } for (const Token* condTok2:conds) { SameExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist, &settings); valueFlowGenericForward(startTok->link()->next(), scope2->bodyEnd, a1, settings); if (is1) { OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist, &settings); valueFlowGenericForward(startTok->link()->next(), scope2->bodyEnd, a2, settings); } } } } } } static bool isTruncated(const ValueType* src, const ValueType* dst, const Settings* settings) { if (src->pointer > 0 || dst->pointer > 0) return src->pointer != dst->pointer; if (src->smartPointer && dst->smartPointer) return false; if ((src->isIntegral() && dst->isIntegral()) || (src->isFloat() && dst->isFloat())) { const size_t srcSize = ValueFlow::getSizeOf(*src, settings); const size_t dstSize = ValueFlow::getSizeOf(*dst, settings); if (srcSize > dstSize) return true; if (srcSize == dstSize && src->sign != dst->sign) return true; } else if (src->type == dst->type) { if (src->type == ValueType::Type::RECORD) return src->typeScope != dst->typeScope; } else { return true; } return false; } static void setSymbolic(ValueFlow::Value& value, const Token* tok) { assert(tok && tok->exprId() > 0 && "Missing expr id for symbolic value"); value.valueType = ValueFlow::Value::ValueType::SYMBOLIC; value.tokvalue = tok; } static ValueFlow::Value makeSymbolic(const Token* tok, MathLib::bigint delta = 0) { ValueFlow::Value value; value.setKnown(); setSymbolic(value, tok); value.intvalue = delta; return value; } static std::set getVarIds(const Token* tok) { std::set result; visitAstNodes(tok, [&](const Token* child) { if (child->varId() > 0) result.insert(child->varId()); return ChildrenToVisit::op1_and_op2; }); return result; } static void valueFlowSymbolic(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings) { for (const Scope* scope : symboldatabase.functionScopes) { for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (!Token::simpleMatch(tok, "=")) continue; if (tok->astParent()) continue; if (!tok->astOperand1()) continue; if (!tok->astOperand2()) continue; if (tok->astOperand1()->hasKnownIntValue()) continue; if (tok->astOperand2()->hasKnownIntValue()) continue; if (tok->astOperand1()->exprId() == 0) continue; if (tok->astOperand2()->exprId() == 0) continue; if (!isConstExpression(tok->astOperand2(), settings->library, tokenlist.isCPP())) continue; if (tok->astOperand1()->valueType() && tok->astOperand2()->valueType()) { if (isTruncated( tok->astOperand2()->valueType(), tok->astOperand1()->valueType(), settings)) continue; } else if (isDifferentType(tok->astOperand2(), tok->astOperand1())) { continue; } const std::set rhsVarIds = getVarIds(tok->astOperand2()); const std::vector vars = getLHSVariables(tok); if (std::any_of(vars.cbegin(), vars.cend(), [&](const Variable* var) { if (rhsVarIds.count(var->declarationId()) > 0) return true; if (var->isLocal()) return var->isStatic(); return !var->isArgument(); })) continue; if (findAstNode(tok, [](const Token* child) { return child->isIncompleteVar(); })) continue; Token* start = nextAfterAstRightmostLeaf(tok); const Token* end = ValueFlow::getEndOfExprScope(tok->astOperand1(), scope); ValueFlow::Value rhs = makeSymbolic(tok->astOperand2()); rhs.errorPath.emplace_back(tok, tok->astOperand1()->expressionString() + " is assigned '" + tok->astOperand2()->expressionString() + "' here."); valueFlowForward(start, end, tok->astOperand1(), rhs, tokenlist, settings); ValueFlow::Value lhs = makeSymbolic(tok->astOperand1()); lhs.errorPath.emplace_back(tok, tok->astOperand1()->expressionString() + " is assigned '" + tok->astOperand2()->expressionString() + "' here."); valueFlowForward(start, end, tok->astOperand2(), lhs, tokenlist, settings); } } } static const Token* isStrlenOf(const Token* tok, const Token* expr, int depth = 10) { if (depth < 0) return nullptr; if (!tok) return nullptr; if (!expr) return nullptr; if (expr->exprId() == 0) return nullptr; if (Token::simpleMatch(tok->previous(), "strlen (")) { if (tok->astOperand2()->exprId() == expr->exprId()) return tok; } else { for (const ValueFlow::Value& v : tok->values()) { if (!v.isSymbolicValue()) continue; if (!v.isKnown()) continue; if (v.intvalue != 0) continue; if (const Token* next = isStrlenOf(v.tokvalue, expr, depth - 1)) return next; } } return nullptr; } static ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, MathLib::bigint val); static void valueFlowSymbolicOperators(const SymbolDatabase& symboldatabase, const Settings* settings) { for (const Scope* scope : symboldatabase.functionScopes) { for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; if (Token::Match(tok, "abs|labs|llabs|fabs|fabsf|fabsl (")) { const Token* arg = tok->next()->astOperand2(); if (!arg) continue; if (arg->exprId() == 0) continue; ValueFlow::Value c = inferCondition(">=", arg, 0); if (!c.isKnown()) continue; ValueFlow::Value v = makeSymbolic(arg); v.errorPath = c.errorPath; v.errorPath.emplace_back(tok, "Passed to " + tok->str()); if (c.intvalue == 0) v.setImpossible(); else v.setKnown(); setTokenValue(tok->next(), std::move(v), settings); } else if (Token::Match(tok, "*|/|<<|>>|^|+|-|%or%")) { if (!tok->astOperand1()) continue; if (!tok->astOperand2()) continue; if (!astIsIntegral(tok->astOperand1(), false) && !astIsIntegral(tok->astOperand2(), false)) continue; const ValueFlow::Value* constant = nullptr; const Token* vartok = nullptr; if (tok->astOperand1()->hasKnownIntValue()) { constant = &tok->astOperand1()->values().front(); vartok = tok->astOperand2(); } if (tok->astOperand2()->hasKnownIntValue()) { constant = &tok->astOperand2()->values().front(); vartok = tok->astOperand1(); } if (!constant) continue; if (!vartok) continue; if (vartok->exprId() == 0) continue; if (Token::Match(tok, "<<|>>|/") && !astIsLHS(vartok)) continue; if (Token::Match(tok, "<<|>>|^|+|-|%or%") && constant->intvalue != 0) continue; if (Token::Match(tok, "*|/") && constant->intvalue != 1) continue; std::vector values = {makeSymbolic(vartok)}; std::unordered_set ids = {vartok->exprId()}; std::copy_if(vartok->values().cbegin(), vartok->values().cend(), std::back_inserter(values), [&](const ValueFlow::Value& v) { if (!v.isSymbolicValue()) return false; if (!v.tokvalue) return false; return ids.insert(v.tokvalue->exprId()).second; }); for (ValueFlow::Value& v : values) setTokenValue(tok, std::move(v), settings); } else if (Token::simpleMatch(tok, "[")) { const Token* arrayTok = tok->astOperand1(); const Token* indexTok = tok->astOperand2(); if (!arrayTok) continue; if (!indexTok) continue; for (const ValueFlow::Value& value : indexTok->values()) { if (!value.isSymbolicValue()) continue; if (value.intvalue != 0) continue; const Token* strlenTok = isStrlenOf(value.tokvalue, arrayTok); if (!strlenTok) continue; ValueFlow::Value v = value; v.bound = ValueFlow::Value::Bound::Point; v.valueType = ValueFlow::Value::ValueType::INT; v.errorPath.emplace_back(strlenTok, "Return index of first '\\0' character in string"); setTokenValue(tok, std::move(v), settings); } } } } } struct SymbolicInferModel : InferModel { const Token* expr; explicit SymbolicInferModel(const Token* tok) : expr(tok) { assert(expr->exprId() != 0); } bool match(const ValueFlow::Value& value) const override { return value.isSymbolicValue() && value.tokvalue && value.tokvalue->exprId() == expr->exprId(); } ValueFlow::Value yield(MathLib::bigint value) const override { ValueFlow::Value result(value); result.valueType = ValueFlow::Value::ValueType::SYMBOLIC; result.tokvalue = expr; result.setKnown(); return result; } }; static void valueFlowSymbolicInfer(const SymbolDatabase& symboldatabase, const Settings* settings) { for (const Scope* scope : symboldatabase.functionScopes) { for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (!Token::Match(tok, "-|%comp%")) continue; if (tok->hasKnownIntValue()) continue; if (!tok->astOperand1()) continue; if (!tok->astOperand2()) continue; if (tok->astOperand1()->exprId() == 0) continue; if (tok->astOperand2()->exprId() == 0) continue; if (tok->astOperand1()->hasKnownIntValue()) continue; if (tok->astOperand2()->hasKnownIntValue()) continue; if (astIsFloat(tok->astOperand1(), false)) continue; if (astIsFloat(tok->astOperand2(), false)) continue; SymbolicInferModel leftModel{tok->astOperand1()}; std::vector values = infer(leftModel, tok->str(), 0, tok->astOperand2()->values()); if (values.empty()) { SymbolicInferModel rightModel{tok->astOperand2()}; values = infer(rightModel, tok->str(), tok->astOperand1()->values(), 0); } for (ValueFlow::Value& value : values) { setTokenValue(tok, std::move(value), settings); } } } } template static void valueFlowForwardConst(Token* start, const Token* end, const Variable* var, const ContainerOfValue& values, const Settings* const settings, int /*unused*/ = 0) { if (!precedes(start, end)) throw InternalError(var->nameToken(), "valueFlowForwardConst: start token does not precede the end token."); for (Token* tok = start; tok != end; tok = tok->next()) { if (tok->varId() == var->declarationId()) { for (const ValueFlow::Value& value : values) setTokenValue(tok, value, settings); } else { [&] { // Follow references auto refs = followAllReferences(tok); auto it = std::find_if(refs.cbegin(), refs.cend(), [&](const ReferenceToken& ref) { return ref.token->varId() == var->declarationId(); }); if (it != refs.end()) { for (ValueFlow::Value value : values) { if (refs.size() > 1) value.setInconclusive(); value.errorPath.insert(value.errorPath.end(), it->errors.cbegin(), it->errors.cend()); setTokenValue(tok, std::move(value), settings); } return; } // Follow symbolic values for (const ValueFlow::Value& v : tok->values()) { if (!v.isSymbolicValue()) continue; if (!v.tokvalue) continue; if (v.tokvalue->varId() != var->declarationId()) continue; for (ValueFlow::Value value : values) { if (v.intvalue != 0) { if (!value.isIntValue()) continue; value.intvalue += v.intvalue; } value.valueKind = v.valueKind; value.bound = v.bound; value.errorPath.insert(value.errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend()); setTokenValue(tok, std::move(value), settings); } } }(); } } } static void valueFlowForwardConst(Token* start, const Token* end, const Variable* var, const std::initializer_list& values, const Settings* const settings) { valueFlowForwardConst(start, end, var, values, settings, 0); } static ValueFlow::Value::Bound findVarBound(const Variable* var, const Token* start, const Token* end, const Settings* settings) { ValueFlow::Value::Bound result = ValueFlow::Value::Bound::Point; const Token* next = start; while ((next = findExpressionChangedSkipDeadCode( var->nameToken(), next->next(), end, settings, true, &evaluateKnownValues))) { ValueFlow::Value::Bound b = ValueFlow::Value::Bound::Point; if (next->varId() != var->declarationId()) return ValueFlow::Value::Bound::Point; if (Token::simpleMatch(next->astParent(), "++")) b = ValueFlow::Value::Bound::Lower; else if (Token::simpleMatch(next->astParent(), "--")) b = ValueFlow::Value::Bound::Upper; else return ValueFlow::Value::Bound::Point; if (result == ValueFlow::Value::Bound::Point) result = b; else if (result != b) return ValueFlow::Value::Bound::Point; } return result; } static bool isInitialVarAssign(const Token* tok) { if (!tok) return false; if (!tok->variable()) return false; if (tok->variable()->nameToken() == tok) return true; const Token* prev = tok->tokAt(2); if (!Token::Match(prev, "%var% ; %var%")) return false; return tok->varId() == prev->varId() && tok->variable()->nameToken() == prev; } static void valueFlowForwardAssign(Token* const tok, const Token* expr, std::vector vars, std::list values, const bool init, TokenList& tokenlist, ErrorLogger* const errorLogger, const Settings* const settings) { if (Token::simpleMatch(tok->astParent(), "return")) return; const Token* endOfVarScope = ValueFlow::getEndOfExprScope(expr); if (std::any_of(values.cbegin(), values.cend(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) { valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); values.remove_if(std::mem_fn(&ValueFlow::Value::isLifetimeValue)); } if (std::all_of( vars.cbegin(), vars.cend(), [&](const Variable* var) { return !var->isPointer() && !var->isSmartPointer(); })) values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue)); if (tok->astParent()) { for (ValueFlow::Value& value : values) { std::string valueKind; if (value.valueKind == ValueFlow::Value::ValueKind::Impossible) { if (value.bound == ValueFlow::Value::Bound::Point) valueKind = "never "; else if (value.bound == ValueFlow::Value::Bound::Lower) valueKind = "less than "; else if (value.bound == ValueFlow::Value::Bound::Upper) valueKind = "greater than "; } std::string info = "Assignment '" + tok->astParent()->expressionString() + "', assigned value is " + valueKind + value.infoString(); value.errorPath.emplace_back(tok, std::move(info)); } } if (tokenlist.isCPP() && vars.size() == 1 && Token::Match(vars.front()->typeStartToken(), "bool|_Bool")) { for (ValueFlow::Value& value : values) { if (value.isImpossible()) continue; if (value.isIntValue()) value.intvalue = (value.intvalue != 0); if (value.isTokValue()) value.intvalue = (value.tokvalue != nullptr); } } // Static variable initialisation? if (vars.size() == 1 && vars.front()->isStatic() && init) lowerToPossible(values); // is volatile if (std::any_of(vars.cbegin(), vars.cend(), [&](const Variable* var) { return var->isVolatile(); })) lowerToPossible(values); // Skip RHS Token* nextExpression = tok->astParent() ? nextAfterAstRightmostLeaf(tok->astParent()) : tok->next(); if (!nextExpression) return; for (ValueFlow::Value& value : values) { if (value.isSymbolicValue()) continue; if (value.isTokValue()) continue; value.tokvalue = tok; } // Const variable if (expr->variable() && expr->variable()->isConst() && !expr->variable()->isReference()) { auto it = std::remove_if(values.begin(), values.end(), [](const ValueFlow::Value& value) { if (!value.isKnown()) return false; if (value.isIntValue()) return true; if (value.isFloatValue()) return true; if (value.isContainerSizeValue()) return true; if (value.isIteratorValue()) return true; return false; }); std::list constValues; constValues.splice(constValues.end(), values, it, values.end()); valueFlowForwardConst(nextExpression, endOfVarScope, expr->variable(), constValues, settings); } if (isInitialVarAssign(expr)) { // Check if variable is only incremented or decremented ValueFlow::Value::Bound b = findVarBound(expr->variable(), nextExpression, endOfVarScope, settings); if (b != ValueFlow::Value::Bound::Point) { auto knownValueIt = std::find_if(values.begin(), values.end(), [](const ValueFlow::Value& value) { if (!value.isKnown()) return false; return value.isIntValue(); }); if (knownValueIt != values.end()) { ValueFlow::Value value = *knownValueIt; value.bound = b; value.invertRange(); value.setImpossible(); valueFlowForwardConst(nextExpression, endOfVarScope, expr->variable(), {value}, settings); } } } valueFlowForward(nextExpression, endOfVarScope, expr, values, tokenlist, settings); } static void valueFlowForwardAssign(Token* const tok, const Variable* const var, const std::list& values, const bool /*unused*/, const bool init, TokenList& tokenlist, ErrorLogger* const errorLogger, const Settings* const settings) { valueFlowForwardAssign(tok, var->nameToken(), {var}, values, init, tokenlist, errorLogger, settings); } static std::list truncateValues(std::list values, const ValueType* dst, const ValueType* src, const Settings* settings) { if (!dst || !dst->isIntegral()) return values; const size_t sz = ValueFlow::getSizeOf(*dst, settings); if (src) { const size_t osz = ValueFlow::getSizeOf(*src, settings); if (osz >= sz && dst->sign == ValueType::Sign::SIGNED && src->sign == ValueType::Sign::UNSIGNED) { values.remove_if([&](const ValueFlow::Value& value) { if (!value.isIntValue()) return false; if (!value.isImpossible()) return false; if (value.bound != ValueFlow::Value::Bound::Upper) return false; if (osz == sz && value.intvalue < 0) return true; if (osz > sz) return true; return false; }); } } for (ValueFlow::Value &value : values) { // Don't truncate impossible values since those can be outside of the valid range if (value.isImpossible()) continue; if (value.isFloatValue()) { value.intvalue = value.floatValue; value.valueType = ValueFlow::Value::ValueType::INT; } if (value.isIntValue() && sz > 0 && sz < 8) { const MathLib::biguint unsignedMaxValue = (1ULL << (sz * 8)) - 1ULL; const MathLib::biguint signBit = 1ULL << (sz * 8 - 1); value.intvalue &= unsignedMaxValue; if (dst->sign == ValueType::Sign::SIGNED && (value.intvalue & signBit)) value.intvalue |= ~unsignedMaxValue; } } return values; } static bool isVariableInit(const Token *tok) { return (tok->str() == "(" || tok->str() == "{") && (tok->isBinaryOp() || (tok->astOperand1() && tok->link() == tok->next())) && tok->astOperand1()->variable() && tok->astOperand1()->variable()->nameToken() == tok->astOperand1() && tok->astOperand1()->variable()->valueType() && tok->astOperand1()->variable()->valueType()->type >= ValueType::Type::VOID && !Token::simpleMatch(tok->astOperand2(), ","); } // Return true if two associative containers intersect template static bool intersects(const C1& c1, const C2& c2) { if (c1.size() > c2.size()) return intersects(c2, c1); // NOLINTNEXTLINE(readability-use-anyofallof) - TODO: fix if possible / also Cppcheck false negative for (auto&& x : c1) { if (c2.find(x) != c2.end()) return true; } return false; } static void valueFlowAfterAssign(TokenList &tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger *errorLogger, const Settings *settings, const std::set& skippedFunctions) { for (const Scope * scope : symboldatabase.functionScopes) { if (skippedFunctions.count(scope)) continue; std::unordered_map> backAssigns; for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { // Assignment bool isInit = false; if (tok->str() != "=" && !(isInit = isVariableInit(tok))) continue; if (tok->astParent() && !((tok->astParent()->str() == ";" && astIsLHS(tok)) || tok->astParent()->str() == "*")) continue; // Lhs should be a variable if (!tok->astOperand1() || !tok->astOperand1()->exprId()) continue; std::vector vars = getLHSVariables(tok); // Rhs values.. Token* rhs = tok->astOperand2(); if (!rhs && isInit) rhs = tok; if (!rhs || rhs->values().empty()) continue; std::list values = truncateValues( rhs->values(), tok->astOperand1()->valueType(), rhs->valueType(), settings); // Remove known values std::set types; if (tok->astOperand1()->hasKnownValue()) { for (const ValueFlow::Value& value:tok->astOperand1()->values()) { if (value.isKnown() && !value.isSymbolicValue()) types.insert(value.valueType); } } values.remove_if([&](const ValueFlow::Value& value) { return types.count(value.valueType) > 0; }); // Remove container size if its not a container if (!astIsContainer(tok->astOperand2())) values.remove_if([&](const ValueFlow::Value& value) { return value.valueType == ValueFlow::Value::ValueType::CONTAINER_SIZE; }); // Remove symbolic values that are the same as the LHS values.remove_if([&](const ValueFlow::Value& value) { if (value.isSymbolicValue() && value.tokvalue) return value.tokvalue->exprId() == tok->astOperand1()->exprId(); return false; }); // Find references to LHS in RHS auto isIncremental = [&](const Token* tok2) -> bool { return findAstNode(tok2, [&](const Token* child) { return child->exprId() == tok->astOperand1()->exprId(); }); }; // Check symbolic values as well const bool incremental = isIncremental(tok->astOperand2()) || std::any_of(values.cbegin(), values.cend(), [&](const ValueFlow::Value& value) { if (!value.isSymbolicValue()) return false; return isIncremental(value.tokvalue); }); // Remove values from the same assignment if it is incremental if (incremental) { values.remove_if([&](const ValueFlow::Value& value) { if (value.tokvalue) return value.tokvalue == tok->astOperand2(); return false; }); } // If assignment copy by value, remove Uninit values.. if ((tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->pointer == 0) || (tok->astOperand1()->variable() && tok->astOperand1()->variable()->isReference() && tok->astOperand1()->variable()->nameToken() == tok->astOperand1())) values.remove_if([&](const ValueFlow::Value& value) { return value.isUninitValue(); }); if (values.empty()) continue; const bool init = vars.size() == 1 && (vars.front()->nameToken() == tok->astOperand1() || tok->isSplittedVarDeclEq()); valueFlowForwardAssign( rhs, tok->astOperand1(), vars, values, init, tokenlist, errorLogger, settings); // Back propagate symbolic values if (tok->astOperand1()->exprId() > 0) { Token* start = nextAfterAstRightmostLeaf(tok); const Token* end = scope->bodyEnd; // Collect symbolic ids std::unordered_set ids; for (const ValueFlow::Value& value : values) { if (!value.isSymbolicValue()) continue; if (!value.tokvalue) continue; if (value.tokvalue->exprId() == 0) continue; ids.insert(value.tokvalue->exprId()); } for (ValueFlow::Value value : values) { if (!value.isSymbolicValue()) continue; const Token* expr = value.tokvalue; value.intvalue = -value.intvalue; value.tokvalue = tok->astOperand1(); // Skip if it intersects with an already assigned symbol auto& s = backAssigns[value.tokvalue->exprId()]; if (intersects(s, ids)) continue; s.insert(expr->exprId()); value.errorPath.emplace_back(tok, tok->astOperand1()->expressionString() + " is assigned '" + tok->astOperand2()->expressionString() + "' here."); valueFlowForward(start, end, expr, value, tokenlist, settings); } } } } } static std::vector getVariables(const Token* tok) { std::vector result; visitAstNodes(tok, [&](const Token* child) { if (child->variable()) result.push_back(child->variable()); return ChildrenToVisit::op1_and_op2; }); return result; } static void valueFlowAfterSwap(TokenList& tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings* settings) { for (const Scope* scope : symboldatabase.functionScopes) { for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (!Token::simpleMatch(tok, "swap (")) continue; if (!Token::simpleMatch(tok->next()->astOperand2(), ",")) continue; std::vector args = astFlatten(tok->next()->astOperand2(), ","); if (args.size() != 2) continue; if (args[0]->exprId() == 0) continue; if (args[1]->exprId() == 0) continue; for (int i = 0; i < 2; i++) { std::vector vars = getVariables(args[0]); const std::list& values = args[0]->values(); valueFlowForwardAssign(args[0], args[1], vars, values, false, tokenlist, errorLogger, settings); std::swap(args[0], args[1]); } } } } static void valueFlowSetConditionToKnown(const Token* tok, std::list& values, bool then) { if (values.empty()) return; if (then && !Token::Match(tok, "==|!|(")) return; if (!then && !Token::Match(tok, "!=|%var%|(")) return; if (isConditionKnown(tok, then)) changePossibleToKnown(values); } static bool isBreakScope(const Token* const endToken) { if (!Token::simpleMatch(endToken, "}")) return false; if (!Token::simpleMatch(endToken->link(), "{")) return false; return Token::findmatch(endToken->link(), "break|goto", endToken); } ValueFlow::Value ValueFlow::asImpossible(ValueFlow::Value v) { v.invertRange(); v.setImpossible(); return v; } static void insertImpossible(std::list& values, const std::list& input) { std::transform(input.cbegin(), input.cend(), std::back_inserter(values), &ValueFlow::asImpossible); } static void insertNegateKnown(std::list& values, const std::list& input) { for (ValueFlow::Value value:input) { if (!value.isIntValue() && !value.isContainerSizeValue()) continue; value.intvalue = !value.intvalue; value.setKnown(); values.push_back(std::move(value)); } } struct ConditionHandler { struct Condition { const Token* vartok{}; std::list true_values; std::list false_values; bool inverted = false; // Whether to insert impossible values for the condition or only use possible values bool impossible = true; bool isBool() const { return astIsBool(vartok); } static MathLib::bigint findPath(const std::list& values) { auto it = std::find_if(values.cbegin(), values.cend(), [](const ValueFlow::Value& v) { return v.path > 0; }); if (it == values.end()) return 0; assert(std::all_of(it, values.end(), [&](const ValueFlow::Value& v) { return v.path == 0 || v.path == it->path; })); return it->path; } MathLib::bigint getPath() const { assert(std::abs(findPath(true_values) - findPath(false_values)) == 0); return findPath(true_values) | findPath(false_values); } Token* getContextAndValues(Token* condTok, std::list& thenValues, std::list& elseValues, bool known = false) const { const MathLib::bigint path = getPath(); const bool allowKnown = path == 0; const bool allowImpossible = impossible && allowKnown; bool inverted2 = inverted; Token* ctx = skipNotAndCasts(condTok, &inverted2); bool then = !inverted || !inverted2; if (!Token::Match(condTok, "!=|=|(|.") && condTok != vartok) { thenValues.insert(thenValues.end(), true_values.cbegin(), true_values.cend()); if (allowImpossible && (known || isConditionKnown(ctx, !then))) insertImpossible(elseValues, false_values); } if (!Token::Match(condTok, "==|!")) { elseValues.insert(elseValues.end(), false_values.cbegin(), false_values.cend()); if (allowImpossible && (known || isConditionKnown(ctx, then))) { insertImpossible(thenValues, true_values); if (isBool()) insertNegateKnown(thenValues, true_values); } } if (inverted2) std::swap(thenValues, elseValues); return ctx; } }; virtual std::vector parse(const Token* tok, const Settings* settings) const = 0; virtual Analyzer::Result forward(Token* start, const Token* stop, const Token* exprTok, const std::list& values, TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) const { return valueFlowForward(start->next(), stop, exprTok, values, tokenlist, settings, loc); } virtual Analyzer::Result forward(Token* top, const Token* exprTok, const std::list& values, TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) const { return valueFlowForwardRecursive(top, exprTok, values, tokenlist, settings, loc); } virtual void reverse(Token* start, const Token* endToken, const Token* exprTok, const std::list& values, TokenList& tokenlist, const Settings* settings, SourceLocation loc = SourceLocation::current()) const { return valueFlowReverse(start, endToken, exprTok, values, tokenlist, settings, loc); } void traverseCondition(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings, const std::set& skippedFunctions, const std::function& f) const { for (const Scope *scope : symboldatabase.functionScopes) { if (skippedFunctions.count(scope)) continue; for (Token *tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (Token::Match(tok, "if|while|for (")) continue; if (Token::Match(tok, ":|;|,")) continue; const Token* top = tok->astTop(); if (!top) continue; if (!Token::Match(top->previous(), "if|while|for (") && !Token::Match(tok->astParent(), "&&|%oror%|?|!")) continue; for (const Condition& cond : parse(tok, settings)) { if (!cond.vartok) continue; if (cond.vartok->exprId() == 0) continue; if (cond.vartok->hasKnownIntValue()) continue; if (cond.true_values.empty() || cond.false_values.empty()) continue; if (!isConstExpression(cond.vartok, settings->library, tokenlist.isCPP())) continue; f(cond, tok, scope); } } } } void beforeCondition(TokenList& tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings* settings, const std::set& skippedFunctions) const { traverseCondition(tokenlist, symboldatabase, settings, skippedFunctions, [&](const Condition& cond, Token* tok, const Scope*) { if (cond.vartok->exprId() == 0) return; // If condition is known then don't propagate value if (tok->hasKnownIntValue()) return; Token* top = tok->astTop(); if (Token::Match(top, "%assign%")) return; if (Token::Match(cond.vartok->astParent(), "%assign%|++|--")) return; if (Token::simpleMatch(tok->astParent(), "?") && tok->astParent()->isExpandedMacro()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable '" + cond.vartok->expressionString() + "', condition is defined in macro"); return; } // if,macro => bailout if (Token::simpleMatch(top->previous(), "if (") && top->previous()->isExpandedMacro()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable '" + cond.vartok->expressionString() + "', condition is defined in macro"); return; } std::list values = cond.true_values; if (cond.true_values != cond.false_values) values.insert(values.end(), cond.false_values.cbegin(), cond.false_values.cend()); // extra logic for unsigned variables 'i>=1' => possible value can also be 0 if (Token::Match(tok, "<|>")) { values.remove_if([](const ValueFlow::Value& v) { if (v.isIntValue()) return v.intvalue != 0; return false; }); if (cond.vartok->valueType() && cond.vartok->valueType()->sign != ValueType::Sign::UNSIGNED) return; } if (values.empty()) return; // bailout: for/while-condition, variable is changed in while loop if (Token::Match(top->previous(), "for|while (") && Token::simpleMatch(top->link(), ") {")) { // Variable changed in 3rd for-expression if (Token::simpleMatch(top->previous(), "for (")) { if (top->astOperand2() && top->astOperand2()->astOperand2() && findExpressionChanged( cond.vartok, top->astOperand2()->astOperand2(), top->link(), settings, tokenlist.isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable '" + cond.vartok->expressionString() + "' used in loop"); return; } } // Variable changed in loop code const Token* const start = top; const Token* const block = top->link()->next(); const Token* const end = block->link(); if (findExpressionChanged(cond.vartok, start, end, settings, tokenlist.isCPP())) { // If its reassigned in loop then analyze from the end if (!Token::Match(tok, "%assign%|++|--") && findExpression(cond.vartok->exprId(), start, end, [&](const Token* tok2) { return Token::Match(tok2->astParent(), "%assign%") && astIsLHS(tok2); })) { // Start at the end of the loop body Token* bodyTok = top->link()->next(); reverse(bodyTok->link(), bodyTok, cond.vartok, values, tokenlist, settings); } if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable '" + cond.vartok->expressionString() + "' used in loop"); return; } } Token* startTok = nullptr; if (astIsRHS(tok)) startTok = tok->astParent(); else if (astIsLHS(tok)) startTok = previousBeforeAstLeftmostLeaf(tok->astParent()); if (!startTok) startTok = tok->previous(); reverse(startTok, nullptr, cond.vartok, values, tokenlist, settings); }); } static Token* skipNotAndCasts(Token* tok, bool* inverted = nullptr) { for (; tok->astParent(); tok = tok->astParent()) { if (Token::simpleMatch(tok->astParent(), "!")) { if (inverted) *inverted ^= true; continue; } if (Token::Match(tok->astParent(), "==|!=")) { const Token* sibling = tok->astSibling(); if (sibling->hasKnownIntValue() && (astIsBool(tok) || astIsBool(sibling))) { const bool value = sibling->values().front().intvalue; if (inverted) *inverted ^= value == Token::simpleMatch(tok->astParent(), "!="); continue; } } if (tok->astParent()->isCast() && astIsBool(tok->astParent())) continue; return tok; } return tok; } static void fillFromPath(ProgramMemory& pm, const Token* top, MathLib::bigint path) { if (path < 1) return; visitAstNodes(top, [&](const Token* tok) { const ValueFlow::Value* v = ValueFlow::findValue(tok->values(), nullptr, [&](const ValueFlow::Value& v) { return v.path == path && isNonConditionalPossibleIntValue(v); }); if (v == nullptr) return ChildrenToVisit::op1_and_op2; pm.setValue(tok, *v); return ChildrenToVisit::op1_and_op2; }); } void afterCondition(TokenList& tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings* settings, const std::set& skippedFunctions) const { traverseCondition(tokenlist, symboldatabase, settings, skippedFunctions, [&](const Condition& cond, Token* condTok, const Scope* scope) { Token* top = condTok->astTop(); const MathLib::bigint path = cond.getPath(); const bool allowKnown = path == 0; std::list thenValues; std::list elseValues; Token* ctx = cond.getContextAndValues(condTok, thenValues, elseValues); if (Token::Match(ctx->astParent(), "%oror%|&&")) { Token* parent = ctx->astParent(); if (astIsRHS(ctx) && astIsLHS(parent) && parent->astParent() && parent->str() == parent->astParent()->str()) parent = parent->astParent(); else if (!astIsLHS(ctx)) { parent = nullptr; } if (parent) { std::vector nextExprs = {parent->astOperand2()}; if (astIsLHS(parent) && parent->astParent() && parent->astParent()->str() == parent->str()) { nextExprs.push_back(parent->astParent()->astOperand2()); } std::list andValues; std::list orValues; cond.getContextAndValues(condTok, andValues, orValues, true); const std::string& op(parent->str()); std::list values; if (op == "&&") values = andValues; else if (op == "||") values = orValues; if (allowKnown && (Token::Match(condTok, "==|!=") || cond.isBool())) changePossibleToKnown(values); if (astIsFloat(cond.vartok, false) || (!cond.vartok->valueType() && std::all_of(values.cbegin(), values.cend(), [](const ValueFlow::Value& v) { return v.isIntValue() || v.isFloatValue(); }))) values.remove_if([&](const ValueFlow::Value& v) { return v.isImpossible(); }); for (Token* start:nextExprs) { Analyzer::Result r = forward(start, cond.vartok, values, tokenlist, settings); if (r.terminate != Analyzer::Terminate::None || r.action.isModified()) return; } } } { const Token* tok2 = condTok; std::string op; bool mixedOperators = false; while (tok2->astParent()) { const Token* parent = tok2->astParent(); if (Token::Match(parent, "%oror%|&&")) { if (op.empty()) { op = parent->str(); } else if (op != parent->str()) { mixedOperators = true; break; } } if (parent->str() == "!") { op = (op == "&&" ? "||" : "&&"); } tok2 = parent; } if (mixedOperators) { return; } } if (!top) return; if (top->previous()->isExpandedMacro()) { for (std::list* values : {&thenValues, &elseValues}) { for (ValueFlow::Value& v : *values) v.macro = true; } } Token* condTop = ctx->astParent(); { bool inverted2 = false; while (Token::Match(condTop, "%oror%|&&")) { Token* parent = skipNotAndCasts(condTop, &inverted2)->astParent(); if (!parent) break; condTop = parent; } if (inverted2) std::swap(thenValues, elseValues); } if (!condTop) return; if (Token::simpleMatch(condTop, "?")) { Token* colon = condTop->astOperand2(); forward(colon->astOperand1(), cond.vartok, thenValues, tokenlist, settings); forward(colon->astOperand2(), cond.vartok, elseValues, tokenlist, settings); // TODO: Handle after condition return; } if (condTop != top && condTop->str() != ";") return; if (!Token::Match(top->previous(), "if|while|for (")) return; if (top->previous()->str() == "for") { if (!Token::Match(condTok, "%comp%")) return; if (!Token::simpleMatch(condTok->astParent(), ";")) return; const Token* stepTok = getStepTok(top); if (cond.vartok->varId() == 0) return; if (!cond.vartok->variable()) return; if (!Token::Match(stepTok, "++|--")) return; std::set bounds; for (const ValueFlow::Value& v : thenValues) { if (v.bound != ValueFlow::Value::Bound::Point && v.isImpossible()) continue; bounds.insert(v.bound); } if (Token::simpleMatch(stepTok, "++") && bounds.count(ValueFlow::Value::Bound::Lower) > 0) return; if (Token::simpleMatch(stepTok, "--") && bounds.count(ValueFlow::Value::Bound::Upper) > 0) return; const Token* childTok = condTok->astOperand1(); if (!childTok) childTok = condTok->astOperand2(); if (!childTok) return; if (childTok->varId() != cond.vartok->varId()) return; const Token* startBlock = top->link()->next(); if (isVariableChanged(startBlock, startBlock->link(), cond.vartok->varId(), cond.vartok->variable()->isGlobal(), settings, tokenlist.isCPP())) return; // Check if condition in for loop is always false const Token* initTok = getInitTok(top); ProgramMemory pm; fillFromPath(pm, initTok, path); fillFromPath(pm, condTok, path); execute(initTok, pm, nullptr, nullptr); MathLib::bigint result = 1; execute(condTok, pm, &result, nullptr); if (result == 0) return; // Remove condition since for condition is not redundant for (std::list* values : {&thenValues, &elseValues}) { for (ValueFlow::Value& v : *values) { v.condition = nullptr; v.conditional = true; } } } bool deadBranch[] = {false, false}; // start token of conditional code Token* startTokens[] = {nullptr, nullptr}; // determine startToken(s) if (Token::simpleMatch(top->link(), ") {")) startTokens[0] = top->link()->next(); if (Token::simpleMatch(top->link()->linkAt(1), "} else {")) startTokens[1] = top->link()->linkAt(1)->tokAt(2); int changeBlock = -1; int bailBlock = -1; for (int i = 0; i < 2; i++) { const Token* const startToken = startTokens[i]; if (!startToken) continue; std::list& values = (i == 0 ? thenValues : elseValues); if (allowKnown) valueFlowSetConditionToKnown(condTok, values, i == 0); Analyzer::Result r = forward(startTokens[i], startTokens[i]->link(), cond.vartok, values, tokenlist, settings); deadBranch[i] = r.terminate == Analyzer::Terminate::Escape; if (r.action.isModified() && !deadBranch[i]) changeBlock = i; if (r.terminate != Analyzer::Terminate::None && r.terminate != Analyzer::Terminate::Escape && r.terminate != Analyzer::Terminate::Modified) bailBlock = i; changeKnownToPossible(values); } if (changeBlock >= 0 && !Token::simpleMatch(top->previous(), "while (")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, startTokens[changeBlock]->link(), "valueFlowAfterCondition: " + cond.vartok->expressionString() + " is changed in conditional block"); return; } if (bailBlock >= 0) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, startTokens[bailBlock]->link(), "valueFlowAfterCondition: bailing in conditional block"); return; } // After conditional code.. if (Token::simpleMatch(top->link(), ") {")) { Token* after = top->link()->linkAt(1); bool dead_if = deadBranch[0]; bool dead_else = deadBranch[1]; const Token* unknownFunction = nullptr; if (condTok->astParent() && Token::Match(top->previous(), "while|for (")) dead_if = !isBreakScope(after); else if (!dead_if) dead_if = isReturnScope(after, &settings->library, &unknownFunction); if (!dead_if && unknownFunction) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope"); return; } if (Token::simpleMatch(after, "} else {")) { after = after->linkAt(2); unknownFunction = nullptr; if (!dead_else) dead_else = isReturnScope(after, &settings->library, &unknownFunction); if (!dead_else && unknownFunction) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope"); return; } } if (dead_if && dead_else) return; std::list values; if (dead_if) { values = elseValues; } else if (dead_else) { values = thenValues; } else { std::copy_if(thenValues.cbegin(), thenValues.cend(), std::back_inserter(values), std::mem_fn(&ValueFlow::Value::isPossible)); std::copy_if(elseValues.cbegin(), elseValues.cend(), std::back_inserter(values), std::mem_fn(&ValueFlow::Value::isPossible)); } if (values.empty()) return; if (dead_if || dead_else) { const Token* parent = condTok->astParent(); // Skip the not operator while (Token::simpleMatch(parent, "!")) parent = parent->astParent(); bool possible = false; if (Token::Match(parent, "&&|%oror%")) { const std::string& op(parent->str()); while (parent && parent->str() == op) parent = parent->astParent(); if (Token::simpleMatch(parent, "!") || Token::simpleMatch(parent, "== false")) possible = op == "||"; else possible = op == "&&"; } if (possible) { values.remove_if(std::mem_fn(&ValueFlow::Value::isImpossible)); changeKnownToPossible(values); } else if (allowKnown) { valueFlowSetConditionToKnown(condTok, values, true); valueFlowSetConditionToKnown(condTok, values, false); } } if (values.empty()) return; const bool isKnown = std::any_of(values.cbegin(), values.cend(), [&](const ValueFlow::Value& v) { return v.isKnown() || v.isImpossible(); }); if (isKnown && isBreakOrContinueScope(after)) { const Scope* loopScope = getLoopScope(cond.vartok); if (loopScope) { Analyzer::Result r = forward(after, loopScope->bodyEnd, cond.vartok, values, tokenlist, settings); if (r.terminate != Analyzer::Terminate::None) return; if (r.action.isModified()) return; Token* start = const_cast(loopScope->bodyEnd); if (Token::simpleMatch(start, "} while (")) { start = start->tokAt(2); forward(start, start->link(), cond.vartok, values, tokenlist, settings); start = start->link(); } values.remove_if(std::mem_fn(&ValueFlow::Value::isImpossible)); changeKnownToPossible(values); } } forward(after, ValueFlow::getEndOfExprScope(cond.vartok, scope), cond.vartok, values, tokenlist, settings); } }); } virtual ~ConditionHandler() = default; ConditionHandler(const ConditionHandler&) = default; protected: ConditionHandler() = default; }; static void valueFlowCondition(const ValuePtr& handler, TokenList& tokenlist, SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings* settings, const std::set& skippedFunctions) { handler->beforeCondition(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions); handler->afterCondition(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions); } struct SimpleConditionHandler : ConditionHandler { std::vector parse(const Token* tok, const Settings* /*settings*/) const override { std::vector conds; parseCompareEachInt(tok, [&](const Token* vartok, ValueFlow::Value true_value, ValueFlow::Value false_value) { if (vartok->hasKnownIntValue()) return; if (vartok->str() == "=" && vartok->astOperand1() && vartok->astOperand2()) vartok = vartok->astOperand1(); Condition cond; cond.true_values.push_back(std::move(true_value)); cond.false_values.push_back(std::move(false_value)); cond.vartok = vartok; conds.push_back(std::move(cond)); }); if (!conds.empty()) return conds; const Token* vartok = nullptr; if (tok->str() == "!") { vartok = tok->astOperand1(); } else if (tok->astParent() && (Token::Match(tok->astParent(), "%oror%|&&|?") || Token::Match(tok->astParent()->previous(), "if|while ("))) { if (Token::simpleMatch(tok, "=")) vartok = tok->astOperand1(); else if (!Token::Match(tok, "%comp%|%assign%")) vartok = tok; } if (!vartok) return {}; Condition cond; cond.true_values.emplace_back(tok, 0LL); cond.false_values.emplace_back(tok, 0LL); cond.vartok = vartok; return {std::move(cond)}; } }; struct IntegralInferModel : InferModel { bool match(const ValueFlow::Value& value) const override { return value.isIntValue(); } ValueFlow::Value yield(MathLib::bigint value) const override { ValueFlow::Value result(value); result.valueType = ValueFlow::Value::ValueType::INT; result.setKnown(); return result; } }; ValuePtr ValueFlow::makeIntegralInferModel() { return IntegralInferModel{}; } ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, MathLib::bigint val) { if (!varTok) return ValueFlow::Value{}; if (varTok->hasKnownIntValue()) return ValueFlow::Value{}; std::vector r = infer(IntegralInferModel{}, op, varTok->values(), val); if (r.size() == 1 && r.front().isKnown()) return r.front(); return ValueFlow::Value{}; } struct IteratorInferModel : InferModel { virtual ValueFlow::Value::ValueType getType() const = 0; bool match(const ValueFlow::Value& value) const override { return value.valueType == getType(); } ValueFlow::Value yield(MathLib::bigint value) const override { ValueFlow::Value result(value); result.valueType = getType(); result.setKnown(); return result; } }; struct EndIteratorInferModel : IteratorInferModel { ValueFlow::Value::ValueType getType() const override { return ValueFlow::Value::ValueType::ITERATOR_END; } }; struct StartIteratorInferModel : IteratorInferModel { ValueFlow::Value::ValueType getType() const override { return ValueFlow::Value::ValueType::ITERATOR_END; } }; static bool isIntegralOnlyOperator(const Token* tok) { return Token::Match(tok, "%|<<|>>|&|^|~|%or%"); } static bool isIntegralOrPointer(const Token* tok) { if (!tok) return false; if (astIsIntegral(tok, false)) return true; if (astIsPointer(tok)) return true; if (Token::Match(tok, "NULL|nullptr")) return true; if (tok->valueType()) return false; // These operators only work on integers if (isIntegralOnlyOperator(tok)) return true; if (isIntegralOnlyOperator(tok->astParent())) return true; if (Token::Match(tok, "+|-|*|/") && tok->isBinaryOp()) return isIntegralOrPointer(tok->astOperand1()) && isIntegralOrPointer(tok->astOperand2()); return false; } static void valueFlowInferCondition(TokenList& tokenlist, const Settings* settings) { for (Token* tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->astParent()) continue; if (tok->hasKnownIntValue()) continue; if (Token::Match(tok, "%comp%|-") && tok->astOperand1() && tok->astOperand2()) { if (astIsIterator(tok->astOperand1()) || astIsIterator(tok->astOperand2())) { static const std::array, 2> iteratorModels = {EndIteratorInferModel{}, StartIteratorInferModel{}}; for (const ValuePtr& model : iteratorModels) { std::vector result = infer(model, tok->str(), tok->astOperand1()->values(), tok->astOperand2()->values()); for (ValueFlow::Value value : result) { value.valueType = ValueFlow::Value::ValueType::INT; setTokenValue(tok, std::move(value), settings); } } } else if (isIntegralOrPointer(tok->astOperand1()) && isIntegralOrPointer(tok->astOperand2())) { std::vector result = infer(IntegralInferModel{}, tok->str(), tok->astOperand1()->values(), tok->astOperand2()->values()); for (ValueFlow::Value& value : result) { setTokenValue(tok, std::move(value), settings); } } } else if (Token::Match(tok->astParent(), "?|&&|!|%oror%") || Token::Match(tok->astParent()->previous(), "if|while (") || (astIsPointer(tok) && isUsedAsBool(tok, settings))) { std::vector result = infer(IntegralInferModel{}, "!=", tok->values(), 0); if (result.size() != 1) continue; ValueFlow::Value value = result.front(); setTokenValue(tok, std::move(value), settings); } } } struct SymbolicConditionHandler : SimpleConditionHandler { static bool isNegatedBool(const Token* tok) { if (!Token::simpleMatch(tok, "!")) return false; return (astIsBool(tok->astOperand1())); } static const Token* skipNot(const Token* tok) { if (!Token::simpleMatch(tok, "!")) return tok; return tok->astOperand1(); } std::vector parse(const Token* tok, const Settings* settings) const override { if (!Token::Match(tok, "%comp%")) return {}; if (tok->hasKnownIntValue()) return {}; if (!tok->astOperand1() || tok->astOperand1()->hasKnownIntValue() || tok->astOperand1()->isLiteral()) return {}; if (!tok->astOperand2() || tok->astOperand2()->hasKnownIntValue() || tok->astOperand2()->isLiteral()) return {}; if (!isConstExpression(tok, settings->library, true)) return {}; std::vector result; auto addCond = [&](const Token* lhsTok, const Token* rhsTok, bool inverted) { for (int i = 0; i < 2; i++) { const bool lhs = i == 0; const Token* vartok = lhs ? lhsTok : rhsTok; const Token* valuetok = lhs ? rhsTok : lhsTok; if (valuetok->exprId() == 0) continue; if (valuetok->hasKnownSymbolicValue(vartok)) continue; if (vartok->hasKnownSymbolicValue(valuetok)) continue; ValueFlow::Value true_value; ValueFlow::Value false_value; setConditionalValues(tok, !lhs, 0, true_value, false_value); setSymbolic(true_value, valuetok); setSymbolic(false_value, valuetok); Condition cond; cond.true_values = {std::move(true_value)}; cond.false_values = {std::move(false_value)}; cond.vartok = vartok; cond.inverted = inverted; result.push_back(std::move(cond)); } }; addCond(tok->astOperand1(), tok->astOperand2(), false); if (Token::Match(tok, "==|!=") && (isNegatedBool(tok->astOperand1()) || isNegatedBool(tok->astOperand2()))) { const Token* lhsTok = skipNot(tok->astOperand1()); const Token* rhsTok = skipNot(tok->astOperand2()); addCond(lhsTok, rhsTok, !(isNegatedBool(tok->astOperand1()) && isNegatedBool(tok->astOperand2()))); } return result; } }; static bool valueFlowForLoop2(const Token *tok, ProgramMemory *memory1, ProgramMemory *memory2, ProgramMemory *memoryAfter) { // for ( firstExpression ; secondExpression ; thirdExpression ) const Token *firstExpression = tok->next()->astOperand2()->astOperand1(); const Token *secondExpression = tok->next()->astOperand2()->astOperand2()->astOperand1(); const Token *thirdExpression = tok->next()->astOperand2()->astOperand2()->astOperand2(); ProgramMemory programMemory; MathLib::bigint result(0); bool error = false; execute(firstExpression, programMemory, &result, &error); if (error) return false; execute(secondExpression, programMemory, &result, &error); if (result == 0) // 2nd expression is false => no looping return false; if (error) { // If a variable is reassigned in second expression, return false bool reassign = false; visitAstNodes(secondExpression, [&](const Token *t) { if (t->str() == "=" && t->astOperand1() && programMemory.hasValue(t->astOperand1()->varId())) // TODO: investigate what variable is assigned. reassign = true; return reassign ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2; }); if (reassign) return false; } ProgramMemory startMemory(programMemory); ProgramMemory endMemory; int maxcount = 10000; while (result != 0 && !error && --maxcount > 0) { endMemory = programMemory; execute(thirdExpression, programMemory, &result, &error); if (!error) execute(secondExpression, programMemory, &result, &error); } if (memory1) memory1->swap(startMemory); if (!error) { if (memory2) memory2->swap(endMemory); if (memoryAfter) memoryAfter->swap(programMemory); } return true; } static void valueFlowForLoopSimplify(Token* const bodyStart, const Token* expr, bool globalvar, const MathLib::bigint value, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) { // TODO: Refactor this to use arbitrary expressions assert(expr->varId() > 0); const Token * const bodyEnd = bodyStart->link(); // Is variable modified inside for loop if (isVariableChanged(bodyStart, bodyEnd, expr->varId(), globalvar, settings, tokenlist.isCPP())) return; for (Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) { if (tok2->varId() == expr->varId()) { const Token * parent = tok2->astParent(); while (parent) { const Token * const p = parent; parent = parent->astParent(); if (!parent || parent->str() == ":") break; if (parent->str() == "?") { if (parent->astOperand2() != p) parent = nullptr; break; } } if (parent) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "For loop variable " + tok2->str() + " stopping on ?"); continue; } ValueFlow::Value value1(value); value1.varId = tok2->varId(); setTokenValue(tok2, std::move(value1), settings); } if (Token::Match(tok2, "%oror%|&&")) { const ProgramMemory programMemory(getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings)); if ((tok2->str() == "&&" && !conditionIsTrue(tok2->astOperand1(), programMemory)) || (tok2->str() == "||" && !conditionIsFalse(tok2->astOperand1(), programMemory))) { // Skip second expression.. Token *parent = tok2; while (parent && parent->str() == tok2->str()) parent = parent->astParent(); // Jump to end of condition if (parent && parent->str() == "(") { tok2 = parent->link(); // cast if (Token::simpleMatch(tok2, ") (")) tok2 = tok2->linkAt(1); } } } const Token* vartok = expr; const Token* rml = nextAfterAstRightmostLeaf(vartok); if (rml) vartok = rml->str() == "]" ? rml : rml->previous(); if (vartok->str() == "]" && vartok->link()->previous()) vartok = vartok->link()->previous(); if ((tok2->str() == "&&" && conditionIsFalse(tok2->astOperand1(), getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings))) || (tok2->str() == "||" && conditionIsTrue(tok2->astOperand1(), getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings)))) break; if (Token::simpleMatch(tok2, ") {")) { if (vartok->varId() && Token::findmatch(tok2->link(), "%varid%", tok2, vartok->varId())) { if (Token::findmatch(tok2, "continue|break|return", tok2->linkAt(1), vartok->varId())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "For loop variable bailout on conditional continue|break|return"); break; } if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "For loop variable skipping conditional scope"); tok2 = tok2->next()->link(); if (Token::simpleMatch(tok2, "} else {")) { if (Token::findmatch(tok2, "continue|break|return", tok2->linkAt(2), vartok->varId())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "For loop variable bailout on conditional continue|break|return"); break; } tok2 = tok2->linkAt(2); } } else { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "For loop skipping {} code"); tok2 = tok2->linkAt(1); if (Token::simpleMatch(tok2, "} else {")) tok2 = tok2->linkAt(2); } } } } static void valueFlowForLoopSimplifyAfter(Token* fortok, nonneg int varid, const MathLib::bigint num, const TokenList& tokenlist, const Settings* settings) { const Token *vartok = nullptr; for (const Token *tok = fortok; tok; tok = tok->next()) { if (tok->varId() == varid) { vartok = tok; break; } } if (!vartok || !vartok->variable()) return; const Variable *var = vartok->variable(); const Token *endToken = nullptr; if (var->isLocal()) endToken = var->scope()->bodyEnd; else endToken = fortok->scope()->bodyEnd; Token* blockTok = fortok->linkAt(1)->linkAt(1); if (blockTok != endToken) { ValueFlow::Value v{num}; v.errorPath.emplace_back(fortok,"After for loop, " + var->name() + " has value " + v.infoString()); valueFlowForward(blockTok->next(), endToken, vartok, v, tokenlist, settings); } } static void valueFlowForLoop(TokenList &tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { for (const Scope &scope : symboldatabase.scopeList) { if (scope.type != Scope::eFor) continue; Token* tok = const_cast(scope.classDef); Token* const bodyStart = const_cast(scope.bodyStart); if (!Token::simpleMatch(tok->next()->astOperand2(), ";") || !Token::simpleMatch(tok->next()->astOperand2()->astOperand2(), ";")) continue; nonneg int varid; bool knownInitValue, partialCond; MathLib::bigint initValue, stepValue, lastValue; if (extractForLoopValues(tok, varid, knownInitValue, initValue, partialCond, stepValue, lastValue)) { const bool executeBody = !knownInitValue || initValue <= lastValue; const Token* vartok = Token::findmatch(tok, "%varid%", bodyStart, varid); if (executeBody && vartok) { std::list initValues; initValues.emplace_back(initValue, ValueFlow::Value::Bound::Lower); initValues.push_back(ValueFlow::asImpossible(initValues.back())); Analyzer::Result result = valueFlowForward(bodyStart, bodyStart->link(), vartok, initValues, tokenlist, settings); if (!result.action.isModified()) { std::list lastValues; lastValues.emplace_back(lastValue, ValueFlow::Value::Bound::Upper); lastValues.back().conditional = true; lastValues.push_back(ValueFlow::asImpossible(lastValues.back())); if (stepValue != 1) lastValues.pop_front(); valueFlowForward(bodyStart, bodyStart->link(), vartok, lastValues, tokenlist, settings); } } const MathLib::bigint afterValue = executeBody ? lastValue + stepValue : initValue; valueFlowForLoopSimplifyAfter(tok, varid, afterValue, tokenlist, settings); } else { ProgramMemory mem1, mem2, memAfter; if (valueFlowForLoop2(tok, &mem1, &mem2, &memAfter)) { for (const auto& p : mem1) { if (!p.second.isIntValue()) continue; if (p.second.isImpossible()) continue; if (p.first.tok->varId() == 0) continue; valueFlowForLoopSimplify(bodyStart, p.first.tok, false, p.second.intvalue, tokenlist, errorLogger, settings); } for (const auto& p : mem2) { if (!p.second.isIntValue()) continue; if (p.second.isImpossible()) continue; if (p.first.tok->varId() == 0) continue; valueFlowForLoopSimplify(bodyStart, p.first.tok, false, p.second.intvalue, tokenlist, errorLogger, settings); } for (const auto& p : memAfter) { if (!p.second.isIntValue()) continue; if (p.second.isImpossible()) continue; if (p.first.tok->varId() == 0) continue; valueFlowForLoopSimplifyAfter(tok, p.first.getExpressionId(), p.second.intvalue, tokenlist, settings); } } } } } struct MultiValueFlowAnalyzer : ValueFlowAnalyzer { std::unordered_map values; std::unordered_map vars; MultiValueFlowAnalyzer(const std::unordered_map& args, const TokenList& t, const Settings* set) : ValueFlowAnalyzer(t, set) { for (const auto& p:args) { values[p.first->declarationId()] = p.second; vars[p.first->declarationId()] = p.first; } } virtual const std::unordered_map& getVars() const { return vars; } const ValueFlow::Value* getValue(const Token* tok) const override { if (tok->varId() == 0) return nullptr; auto it = values.find(tok->varId()); if (it == values.end()) return nullptr; return &it->second; } ValueFlow::Value* getValue(const Token* tok) override { if (tok->varId() == 0) return nullptr; auto it = values.find(tok->varId()); if (it == values.end()) return nullptr; return &it->second; } void makeConditional() override { for (auto&& p:values) { p.second.conditional = true; } } void addErrorPath(const Token* tok, const std::string& s) override { for (auto&& p:values) { p.second.errorPath.emplace_back(tok, s); } } bool isAlias(const Token* tok, bool& inconclusive) const override { const auto range = SelectValueFromVarIdMapRange(&values); for (const auto& p:getVars()) { nonneg int const varid = p.first; const Variable* var = p.second; if (tok->varId() == varid) return true; if (isAliasOf(var, tok, varid, range, &inconclusive)) return true; } return false; } bool lowerToPossible() override { for (auto&& p:values) { if (p.second.isImpossible()) return false; p.second.changeKnownToPossible(); } return true; } bool lowerToInconclusive() override { for (auto&& p:values) { if (p.second.isImpossible()) return false; p.second.setInconclusive(); } return true; } bool isConditional() const override { for (auto&& p:values) { if (p.second.conditional) return true; if (p.second.condition) return !p.second.isImpossible(); } return false; } bool stopOnCondition(const Token* /*condTok*/) const override { // TODO fix false negatives return true; // isConditional(); } bool updateScope(const Token* endBlock, bool /*modified*/) const override { const Scope* scope = endBlock->scope(); if (!scope) return false; if (scope->type == Scope::eLambda) { return std::all_of(values.cbegin(), values.cend(), [](const std::pair& p) { return p.second.isLifetimeValue(); }); } if (scope->type == Scope::eIf || scope->type == Scope::eElse || scope->type == Scope::eWhile || scope->type == Scope::eFor) { auto pred = [](const ValueFlow::Value& value) { if (value.isKnown()) return true; if (value.isImpossible()) return true; if (value.isLifetimeValue()) return true; return false; }; if (std::all_of(values.cbegin(), values.cend(), std::bind(pred, std::bind(SelectMapValues{}, std::placeholders::_1)))) return true; if (isConditional()) return false; const Token* condTok = getCondTokFromEnd(endBlock); std::set varids; std::transform(getVars().cbegin(), getVars().cend(), std::inserter(varids, varids.begin()), SelectMapKeys{}); return bifurcate(condTok, varids, getSettings()); } return false; } bool match(const Token* tok) const override { return values.count(tok->varId()) > 0; } ProgramState getProgramState() const override { ProgramState ps; for (const auto& p : values) { const Variable* var = vars.at(p.first); if (!var) continue; ps[var->nameToken()] = p.second; } return ps; } }; template bool productParams(const Settings* settings, const std::unordered_map>& vars, F f) { using Args = std::vector>; Args args(1); // Compute cartesian product of all arguments for (const auto& p:vars) { if (p.second.empty()) continue; args.back()[p.first] = p.second.front(); } bool bail = false; int max = 8; if (settings) max = settings->performanceValueFlowMaxSubFunctionArgs; for (const auto& p:vars) { if (args.size() > max) { bail = true; break; } if (p.second.empty()) continue; std::for_each(std::next(p.second.begin()), p.second.end(), [&](const ValueFlow::Value& value) { Args new_args; for (auto arg:args) { if (value.path != 0) { for (const auto& q:arg) { if (q.first == p.first) continue; if (q.second.path == 0) continue; if (q.second.path != value.path) return; } } arg[p.first] = value; new_args.push_back(std::move(arg)); } std::copy(new_args.cbegin(), new_args.cend(), std::back_inserter(args)); }); } if (args.size() > max) { bail = true; args.resize(max); } for (const auto& arg:args) { if (arg.empty()) continue; // Make sure all arguments are the same path const MathLib::bigint path = arg.cbegin()->second.path; if (std::any_of(arg.cbegin(), arg.cend(), [&](const std::pair& p) { return p.second.path != path; })) continue; f(arg); } return !bail; } static void valueFlowInjectParameter(TokenList& tokenlist, ErrorLogger* errorLogger, const Settings& settings, const Scope* functionScope, const std::unordered_map>& vars) { const bool r = productParams(&settings, vars, [&](const std::unordered_map& arg) { MultiValueFlowAnalyzer a(arg, tokenlist, &settings); valueFlowGenericForward(const_cast(functionScope->bodyStart), functionScope->bodyEnd, a, settings); }); if (!r) { std::string fname = ""; if (const Function* f = functionScope->function) fname = f->name(); if (settings.debugwarnings) bailout(tokenlist, errorLogger, functionScope->bodyStart, "Too many argument passed to " + fname); } } static void valueFlowInjectParameter(const TokenList& tokenlist, const Settings* settings, const Variable* arg, const Scope* functionScope, const std::list& argvalues) { // Is argument passed by value or const reference, and is it a known non-class type? if (arg->isReference() && !arg->isConst() && !arg->isClass()) return; // Set value in function scope.. const nonneg int varid2 = arg->declarationId(); if (!varid2) return; valueFlowForward(const_cast(functionScope->bodyStart->next()), functionScope->bodyEnd, arg->nameToken(), argvalues, tokenlist, settings); } static void valueFlowSwitchVariable(TokenList &tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { for (const Scope &scope : symboldatabase.scopeList) { if (scope.type != Scope::ScopeType::eSwitch) continue; if (!Token::Match(scope.classDef, "switch ( %var% ) {")) continue; const Token *vartok = scope.classDef->tokAt(2); const Variable *var = vartok->variable(); if (!var) continue; // bailout: global non-const variables if (!(var->isLocal() || var->isArgument()) && !var->isConst()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, vartok, "switch variable " + var->name() + " is global"); continue; } for (const Token *tok = scope.bodyStart->next(); tok != scope.bodyEnd; tok = tok->next()) { if (tok->str() == "{") { tok = tok->link(); continue; } if (Token::Match(tok, "case %num% :")) { std::list values; values.emplace_back(MathLib::toBigNumber(tok->next()->str())); values.back().condition = tok; values.back().errorPath.emplace_back(tok, "case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here."); bool known = false; if ((Token::simpleMatch(tok->previous(), "{") || Token::simpleMatch(tok->tokAt(-2), "break ;")) && !Token::Match(tok->tokAt(3), ";| case")) known = true; while (Token::Match(tok->tokAt(3), ";| case %num% :")) { known = false; tok = tok->tokAt(3); if (!tok->isName()) tok = tok->next(); values.emplace_back(MathLib::toBigNumber(tok->next()->str())); values.back().condition = tok; values.back().errorPath.emplace_back(tok, "case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here."); } for (std::list::const_iterator val = values.cbegin(); val != values.cend(); ++val) { valueFlowReverse(tokenlist, const_cast(scope.classDef), vartok, *val, ValueFlow::Value(), errorLogger, settings); } if (vartok->variable()->scope()) { if (known) values.back().setKnown(); // FIXME We must check if there is a return. See #9276 /* valueFlowForwardVariable(tok->tokAt(3), vartok->variable()->scope()->bodyEnd, vartok->variable(), vartok->varId(), values, values.back().isKnown(), false, tokenlist, errorLogger, settings); */ } } } } } static std::list getFunctionArgumentValues(const Token *argtok) { std::list argvalues(argtok->values()); removeImpossible(argvalues); if (argvalues.empty() && Token::Match(argtok, "%comp%|%oror%|&&|!")) { argvalues.emplace_back(0); argvalues.emplace_back(1); } return argvalues; } static void valueFlowLibraryFunction(Token *tok, const std::string &returnValue, const Settings *settings) { std::unordered_map> argValues; int argn = 1; for (const Token *argtok : getArguments(tok->previous())) { argValues[argn] = getFunctionArgumentValues(argtok); argn++; } if (returnValue.find("arg") != std::string::npos && argValues.empty()) return; productParams(settings, argValues, [&](const std::unordered_map& arg) { ValueFlow::Value value = evaluateLibraryFunction(arg, returnValue, settings); if (value.isUninitValue()) return; ValueFlow::Value::ValueKind kind = ValueFlow::Value::ValueKind::Known; for (auto&& p : arg) { if (p.second.isPossible()) kind = p.second.valueKind; if (p.second.isInconclusive()) { kind = p.second.valueKind; break; } } if (value.isImpossible() && kind != ValueFlow::Value::ValueKind::Known) return; if (!value.isImpossible()) value.valueKind = kind; setTokenValue(tok, std::move(value), settings); }); } template struct IteratorRange { Iterator mBegin; Iterator mEnd; Iterator begin() const { return mBegin; } Iterator end() const { return mEnd; } }; template IteratorRange MakeIteratorRange(Iterator start, Iterator last) { return {start, last}; } static void valueFlowSubFunction(TokenList& tokenlist, SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings& settings) { int id = 0; for (const Scope* scope : MakeIteratorRange(symboldatabase.functionScopes.crbegin(), symboldatabase.functionScopes.crend())) { const Function* function = scope->function; if (!function) continue; for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (tok->isKeyword() || !Token::Match(tok, "%name% (")) continue; const Function * const calledFunction = tok->function(); if (!calledFunction) { // library function? const std::string& returnValue(settings.library.returnValue(tok)); if (!returnValue.empty()) valueFlowLibraryFunction(tok->next(), returnValue, &settings); continue; } const Scope * const calledFunctionScope = calledFunction->functionScope; if (!calledFunctionScope) continue; id++; std::unordered_map> argvars; // TODO: Rewrite this. It does not work well to inject 1 argument at a time. const std::vector &callArguments = getArguments(tok); for (int argnr = 0U; argnr < callArguments.size(); ++argnr) { const Token *argtok = callArguments[argnr]; // Get function argument const Variable * const argvar = calledFunction->getArgumentVar(argnr); if (!argvar) break; // passing value(s) to function std::list argvalues(getFunctionArgumentValues(argtok)); // Remove non-local lifetimes argvalues.remove_if([](const ValueFlow::Value& v) { if (v.isLifetimeValue()) return !v.isLocalLifetimeValue() && !v.isSubFunctionLifetimeValue(); return false; }); // Remove uninit values if argument is passed by value if (argtok->variable() && !argtok->variable()->isPointer() && argvalues.size() == 1 && argvalues.front().isUninitValue()) { if (CheckUninitVar::isVariableUsage(tokenlist.isCPP(), argtok, settings.library, false, CheckUninitVar::Alloc::NO_ALLOC, 0)) continue; } if (argvalues.empty()) continue; // Error path.. for (ValueFlow::Value &v : argvalues) { const std::string nr = std::to_string(argnr + 1) + getOrdinalText(argnr + 1); v.errorPath.emplace_back(argtok, "Calling function '" + calledFunction->name() + "', " + nr + " argument '" + argtok->expressionString() + "' value is " + v.infoString()); v.path = 256 * v.path + id % 256; // Change scope of lifetime values if (v.isLifetimeValue()) v.lifetimeScope = ValueFlow::Value::LifetimeScope::SubFunction; } // passed values are not "known".. lowerToPossible(argvalues); argvars[argvar] = argvalues; } valueFlowInjectParameter(tokenlist, errorLogger, settings, calledFunctionScope, argvars); } } } static void valueFlowFunctionDefaultParameter(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings) { if (!tokenlist.isCPP()) return; for (const Scope* scope : symboldatabase.functionScopes) { const Function* function = scope->function; if (!function) continue; for (std::size_t arg = function->minArgCount(); arg < function->argCount(); arg++) { const Variable* var = function->getArgumentVar(arg); if (var && var->hasDefault() && Token::Match(var->nameToken(), "%var% = %num%|%str% [,)]")) { const std::list &values = var->nameToken()->tokAt(2)->values(); std::list argvalues; for (const ValueFlow::Value &value : values) { ValueFlow::Value v(value); v.defaultArg = true; v.changeKnownToPossible(); if (v.isPossible()) argvalues.push_back(std::move(v)); } if (!argvalues.empty()) valueFlowInjectParameter(tokenlist, settings, var, scope, argvalues); } } } } static const ValueFlow::Value* getKnownValueFromToken(const Token* tok) { if (!tok) return nullptr; auto it = std::find_if(tok->values().begin(), tok->values().end(), [&](const ValueFlow::Value& v) { return (v.isIntValue() || v.isContainerSizeValue() || v.isFloatValue()) && v.isKnown(); }); if (it == tok->values().end()) return nullptr; return std::addressof(*it); } static const ValueFlow::Value* getKnownValueFromTokens(const std::vector& toks) { if (toks.empty()) return nullptr; const ValueFlow::Value* result = getKnownValueFromToken(toks.front()); if (!result) return nullptr; if (!std::all_of(std::next(toks.begin()), toks.end(), [&](const Token* tok) { return std::any_of(tok->values().begin(), tok->values().end(), [&](const ValueFlow::Value& v) { return v.equalValue(*result) && v.valueKind == result->valueKind; }); })) return nullptr; return result; } static void setFunctionReturnValue(const Function* f, Token* tok, ValueFlow::Value v, const Settings* settings) { if (f->hasVirtualSpecifier()) { if (v.isImpossible()) return; v.setPossible(); } else if (!v.isImpossible()) { v.setKnown(); } v.errorPath.emplace_back(tok, "Calling function '" + f->name() + "' returns " + v.toString()); setTokenValue(tok, std::move(v), settings); } static void valueFlowFunctionReturn(TokenList &tokenlist, ErrorLogger *errorLogger, const Settings* settings) { for (Token *tok = tokenlist.back(); tok; tok = tok->previous()) { if (tok->str() != "(" || !tok->astOperand1()) continue; const Function* function = nullptr; if (Token::Match(tok->previous(), "%name% (")) function = tok->previous()->function(); else function = tok->astOperand1()->function(); if (!function) continue; // TODO: Check if member variable is a pointer or reference if (function->isImplicitlyVirtual() && !function->hasFinalSpecifier()) continue; if (tok->hasKnownValue()) continue; std::vector returns = Function::findReturns(function); if (returns.empty()) continue; if (const ValueFlow::Value* v = getKnownValueFromTokens(returns)) { setFunctionReturnValue(function, tok, *v, settings); continue; } // Arguments.. std::vector arguments = getArguments(tok); ProgramMemory programMemory; for (std::size_t i = 0; i < arguments.size(); ++i) { const Variable * const arg = function->getArgumentVar(i); if (!arg) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "function return; unhandled argument type"); programMemory.clear(); break; } const ValueFlow::Value* v = getKnownValueFromToken(arguments[i]); if (!v) continue; programMemory.setValue(arg->nameToken(), *v); } if (programMemory.empty() && !arguments.empty()) continue; std::vector values = execute(function->functionScope, programMemory, settings); for (const ValueFlow::Value& v : values) { if (v.isUninitValue()) continue; setFunctionReturnValue(function, tok, v, settings); } } } static bool needsInitialization(const Variable* var, bool cpp) { if (!var) return false; if (var->hasDefault()) return false; if (var->isPointer()) return true; if (var->type() && var->type()->isUnionType()) return false; if (!cpp) return true; if (var->type() && var->type()->needInitialization == Type::NeedInitialization::True) return true; if (var->valueType()) { if (var->valueType()->isPrimitive()) return true; if (var->valueType()->type == ValueType::Type::POD) return true; if (var->valueType()->type == ValueType::Type::ITERATOR) return true; } return false; } static void addToErrorPath(ValueFlow::Value& value, const ValueFlow::Value& from) { std::unordered_set locations; std::transform(value.errorPath.cbegin(), value.errorPath.cend(), std::inserter(locations, locations.begin()), [](const ErrorPathItem& e) { return e.first; }); if (from.condition && !value.condition) value.condition = from.condition; std::copy_if(from.errorPath.cbegin(), from.errorPath.cend(), std::back_inserter(value.errorPath), [&](const ErrorPathItem& e) { return locations.insert(e.first).second; }); } static std::vector findAllUsages(const Variable* var, Token* start, // cppcheck-suppress constParameterPointer // FP const Library* library) { // std::vector result; const Scope* scope = var->scope(); if (!scope) return {}; return findTokensSkipDeadCode(library, start, scope->bodyEnd, [&](const Token* tok) { return tok->varId() == var->declarationId(); }); } static Token* findStartToken(const Variable* var, Token* start, const Library* library) { std::vector uses = findAllUsages(var, start, library); if (uses.empty()) return start; Token* first = uses.front(); if (Token::findmatch(start, "goto|asm|setjmp|longjmp", first)) return start; if (first != var->nameToken()) { // if this is lhs in assignment then set first to the first token in LHS expression Token* temp = first; while (Token::Match(temp->astParent(), "[&*(]") && precedes(temp->astParent(), temp)) temp = temp->astParent(); if (Token::simpleMatch(temp->astParent(), "=") && precedes(temp, temp->astParent())) first = temp; } // If there is only one usage if (uses.size() == 1) return first->previous(); const Scope* scope = first->scope(); // If first usage is in variable scope if (scope == var->scope()) { bool isLoopExpression = false; for (const Token* parent = first; parent; parent = parent->astParent()) { if (Token::simpleMatch(parent->astParent(), ";") && Token::simpleMatch(parent->astParent()->astParent(), ";") && Token::simpleMatch(parent->astParent()->astParent()->astParent(), "(") && Token::simpleMatch(parent->astParent()->astParent()->astParent()->astOperand1(), "for (") && parent == parent->astParent()->astParent()->astParent()->astOperand2()->astOperand2()->astOperand2()) { isLoopExpression = true; } } return isLoopExpression ? start : first->previous(); } // If all uses are in the same scope if (std::all_of(uses.begin() + 1, uses.end(), [&](const Token* tok) { return tok->scope() == scope; })) return first->previous(); // Compute the outer scope while (scope && scope->nestedIn != var->scope()) scope = scope->nestedIn; if (!scope) return start; Token* tok = const_cast(scope->bodyStart); if (!tok) return start; if (Token::simpleMatch(tok->tokAt(-2), "} else {")) tok = tok->linkAt(-2); if (Token::simpleMatch(tok->previous(), ") {")) return tok->linkAt(-1)->previous(); return tok; } static void valueFlowUninit(TokenList& tokenlist, const Settings* settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->scope()->isExecutable()) continue; if (!Token::Match(tok, "%var% ;|[")) continue; const Variable* var = tok->variable(); if (!var) continue; if (var->nameToken() != tok || var->isInit()) continue; if (!needsInitialization(var, tokenlist.isCPP())) continue; if (!var->isLocal() || var->isStatic() || var->isExtern() || var->isReference() || var->isThrow()) continue; ValueFlow::Value uninitValue; uninitValue.setKnown(); uninitValue.valueType = ValueFlow::Value::ValueType::UNINIT; uninitValue.tokvalue = tok; if (var->isArray()) uninitValue.indirect = var->dimensions().size(); bool partial = false; Token* start = findStartToken(var, tok->next(), &settings->library); std::map partialReads; if (const Scope* scope = var->typeScope()) { if (Token::findsimplematch(scope->bodyStart, "union", scope->bodyEnd)) continue; for (const Variable& memVar : scope->varlist) { if (!memVar.isPublic()) continue; // Skip array since we can't track partial initialization from nested subexpressions if (memVar.isArray()) continue; if (!needsInitialization(&memVar, tokenlist.isCPP())) { partial = true; continue; } MemberExpressionAnalyzer analyzer(memVar.nameToken()->str(), tok, uninitValue, tokenlist, settings); valueFlowGenericForward(start, tok->scope()->bodyEnd, analyzer, *settings); for (auto&& p : *analyzer.partialReads) { Token* tok2 = p.first; const ValueFlow::Value& v = p.second; // Try to insert into map auto pp = partialReads.insert(std::make_pair(tok2, v)); ValueFlow::Value& v2 = pp.first->second; const bool inserted = pp.second; // Merge the two values if it is already in map if (!inserted) { if (v.valueType != v2.valueType) continue; addToErrorPath(v2, v); } v2.subexpressions.push_back(memVar.nameToken()->str()); } } } for (auto&& p : partialReads) { Token* tok2 = p.first; ValueFlow::Value& v = p.second; setTokenValue(tok2, std::move(v), settings); } if (partial) continue; valueFlowForward(start, tok->scope()->bodyEnd, var->nameToken(), uninitValue, tokenlist, settings); } } static bool isContainerSizeChanged(const Token* expr, const Token* start, const Token* end, int indirect, const Settings* settings = nullptr, int depth = 20); static bool isContainerSizeChangedByFunction(const Token* tok, int indirect, const Settings* settings = nullptr, int depth = 20) { if (!tok->valueType()) return false; if (!astIsContainer(tok)) return false; // If we are accessing an element then we are not changing the container size if (Token::Match(tok, "%name% . %name% (")) { const Library::Container::Yield yield = getLibraryContainer(tok)->getYield(tok->strAt(2)); if (yield != Library::Container::Yield::NO_YIELD) return false; } if (Token::simpleMatch(tok->astParent(), "[")) return false; // address of variable const bool addressOf = tok->valueType()->pointer || (tok->astParent() && tok->astParent()->isUnaryOp("&")); int narg; const Token * ftok = getTokenArgumentFunction(tok, narg); if (!ftok) return false; // not a function => variable not changed const Function * fun = ftok->function(); if (fun && !fun->isImplicitlyVirtual()) { const Variable *arg = fun->getArgumentVar(narg); if (arg) { const bool isPointer = addressOf || indirect > 0; if (!arg->isReference() && !isPointer) return false; if (!isPointer && arg->isConst()) return false; if (arg->valueType() && arg->valueType()->constness == 1) return false; const Scope * scope = fun->functionScope; if (scope) { // Argument not used if (!arg->nameToken()) return false; if (depth > 0) return isContainerSizeChanged(arg->nameToken(), scope->bodyStart, scope->bodyEnd, addressOf ? indirect + 1 : indirect, settings, depth - 1); } // Don't know => Safe guess return true; } } bool inconclusive = false; const bool isChanged = isVariableChangedByFunctionCall(tok, indirect, settings, &inconclusive); return (isChanged || inconclusive); } struct ContainerExpressionAnalyzer : ExpressionAnalyzer { ContainerExpressionAnalyzer(const Token* expr, ValueFlow::Value val, const TokenList& t, const Settings* s) : ExpressionAnalyzer(expr, std::move(val), t, s) {} bool match(const Token* tok) const override { return tok->exprId() == expr->exprId() || (astIsIterator(tok) && isAliasOf(tok, expr->exprId())); } Action isWritable(const Token* tok, Direction /*d*/) const override { if (astIsIterator(tok)) return Action::None; if (!getValue(tok)) return Action::None; if (!tok->valueType()) return Action::None; if (!astIsContainer(tok)) return Action::None; const Token* parent = tok->astParent(); const Library::Container* container = getLibraryContainer(tok); if (container->stdStringLike && Token::simpleMatch(parent, "+=") && astIsLHS(tok) && parent->astOperand2()) { const Token* rhs = parent->astOperand2(); if (rhs->tokType() == Token::eString) return Action::Read | Action::Write | Action::Incremental; const Library::Container* rhsContainer = getLibraryContainer(rhs); if (rhsContainer && rhsContainer->stdStringLike) { if (std::any_of(rhs->values().cbegin(), rhs->values().cend(), [&](const ValueFlow::Value &rhsval) { return rhsval.isKnown() && rhsval.isContainerSizeValue(); })) return Action::Read | Action::Write | Action::Incremental; } } else if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (")) { const Library::Container::Action action = container->getAction(tok->astParent()->strAt(1)); if (action == Library::Container::Action::PUSH || action == Library::Container::Action::POP) { std::vector args = getArguments(tok->tokAt(3)); if (args.size() < 2) return Action::Read | Action::Write | Action::Incremental; } } return Action::None; } void writeValue(ValueFlow::Value* val, const Token* tok, Direction d) const override { if (!val) return; if (!tok->astParent()) return; if (!tok->valueType()) return; if (!astIsContainer(tok)) return; const Token* parent = tok->astParent(); const Library::Container* container = getLibraryContainer(tok); int n = 0; if (container->stdStringLike && Token::simpleMatch(parent, "+=") && parent->astOperand2()) { const Token* rhs = parent->astOperand2(); const Library::Container* rhsContainer = getLibraryContainer(rhs); if (rhs->tokType() == Token::eString) n = Token::getStrLength(rhs); else if (rhsContainer && rhsContainer->stdStringLike) { auto it = std::find_if(rhs->values().begin(), rhs->values().end(), [&](const ValueFlow::Value& rhsval) { return rhsval.isKnown() && rhsval.isContainerSizeValue(); }); if (it != rhs->values().end()) n = it->intvalue; } } else if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (")) { const Library::Container::Action action = container->getAction(tok->astParent()->strAt(1)); if (action == Library::Container::Action::PUSH) n = 1; if (action == Library::Container::Action::POP) n = -1; } if (d == Direction::Reverse) val->intvalue -= n; else val->intvalue += n; } int getIndirect(const Token* tok) const override { if (tok->valueType()) { return tok->valueType()->pointer; } return ValueFlowAnalyzer::getIndirect(tok); } Action isModified(const Token* tok) const override { Action read = Action::Read; // An iterator won't change the container size if (astIsIterator(tok)) return read; if (Token::Match(tok->astParent(), "%assign%") && astIsLHS(tok)) return Action::Invalid; if (isLikelyStreamRead(isCPP(), tok->astParent())) return Action::Invalid; if (astIsContainer(tok) && ValueFlow::isContainerSizeChanged(tok, getIndirect(tok), getSettings())) return read | Action::Invalid; return read; } }; static const Token* parseBinaryIntOp(const Token* expr, const std::function(const Token*)>& eval, MathLib::bigint& known) { if (!expr) return nullptr; if (!expr->astOperand1() || !expr->astOperand2()) return nullptr; if (expr->astOperand1()->exprId() == 0 && expr->astOperand2()->exprId() == 0) return nullptr; std::vector x1 = eval(expr->astOperand1()); std::vector x2 = eval(expr->astOperand2()); if (expr->astOperand1()->exprId() == 0 && x1.empty()) return nullptr; if (expr->astOperand2()->exprId() == 0 && x2.empty()) return nullptr; const Token* varTok = nullptr; if (!x1.empty() && x2.empty()) { varTok = expr->astOperand2(); known = x1.front(); } else if (x1.empty() && !x2.empty()) { varTok = expr->astOperand1(); known = x2.front(); } return varTok; } const Token* ValueFlow::solveExprValue(const Token* expr, const std::function(const Token*)>& eval, ValueFlow::Value& value) { if (!value.isIntValue() && !value.isIteratorValue() && !value.isSymbolicValue()) return expr; if (value.isSymbolicValue() && !Token::Match(expr, "+|-")) return expr; MathLib::bigint intval; const Token* binaryTok = parseBinaryIntOp(expr, eval, intval); const bool rhs = astIsRHS(binaryTok); // If its on the rhs, then -1 multiplication is needed, which is not possible with simple delta analysis used currently for symbolic values if (value.isSymbolicValue() && rhs && Token::simpleMatch(expr, "-")) return expr; if (binaryTok && expr->str().size() == 1) { switch (expr->str()[0]) { case '+': { value.intvalue -= intval; return ValueFlow::solveExprValue(binaryTok, eval, value); } case '-': { if (rhs) value.intvalue = intval - value.intvalue; else value.intvalue += intval; return ValueFlow::solveExprValue(binaryTok, eval, value); } case '*': { if (intval == 0) break; value.intvalue /= intval; return ValueFlow::solveExprValue(binaryTok, eval, value); } case '^': { value.intvalue ^= intval; return ValueFlow::solveExprValue(binaryTok, eval, value); } } } return expr; } static const Token* solveExprValue(const Token* expr, ValueFlow::Value& value) { return ValueFlow::solveExprValue( expr, [](const Token* tok) -> std::vector { if (tok->hasKnownIntValue()) return {tok->values().front().intvalue}; return {}; }, value); } ValuePtr makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings) { if (value.isContainerSizeValue()) return ContainerExpressionAnalyzer(exprTok, std::move(value), tokenlist, settings); const Token* expr = solveExprValue(exprTok, value); return ExpressionAnalyzer(expr, std::move(value), tokenlist, settings); } ValuePtr makeReverseAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings) { if (value.isContainerSizeValue()) return ContainerExpressionAnalyzer(exprTok, std::move(value), tokenlist, settings); return ExpressionAnalyzer(exprTok, std::move(value), tokenlist, settings); } bool ValueFlow::isContainerSizeChanged(const Token* tok, int indirect, const Settings* settings, int depth) { if (!tok) return false; if (!tok->valueType() || !tok->valueType()->container) return true; if (astIsLHS(tok) && Token::Match(tok->astParent(), "%assign%|<<")) return true; const Library::Container* container = tok->valueType()->container; if (astIsLHS(tok) && Token::simpleMatch(tok->astParent(), "[")) return container->stdAssociativeLike; const Library::Container::Action action = astContainerAction(tok); switch (action) { case Library::Container::Action::RESIZE: case Library::Container::Action::CLEAR: case Library::Container::Action::PUSH: case Library::Container::Action::POP: case Library::Container::Action::CHANGE: case Library::Container::Action::INSERT: case Library::Container::Action::ERASE: return true; case Library::Container::Action::NO_ACTION: // Is this an unknown member function call? if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (")) { const Library::Container::Yield yield = astContainerYield(tok); return yield == Library::Container::Yield::NO_YIELD; } break; case Library::Container::Action::FIND: case Library::Container::Action::CHANGE_CONTENT: case Library::Container::Action::CHANGE_INTERNAL: break; } return isContainerSizeChangedByFunction(tok, indirect, settings, depth); } static bool isContainerSizeChanged(const Token* expr, const Token* start, const Token* end, int indirect, const Settings* settings, int depth) { for (const Token *tok = start; tok != end; tok = tok->next()) { if (tok->exprId() != expr->exprId() && !isAliasOf(tok, expr)) continue; if (ValueFlow::isContainerSizeChanged(tok, indirect, settings, depth)) return true; } return false; } static void valueFlowSmartPointer(TokenList &tokenlist, ErrorLogger * errorLogger, const Settings *settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->scope()) continue; if (!tok->scope()->isExecutable()) continue; if (!astIsSmartPointer(tok)) continue; if (tok->variable() && Token::Match(tok, "%var% (|{|;")) { const Variable* var = tok->variable(); if (!var->isSmartPointer()) continue; if (var->nameToken() == tok) { if (Token::Match(tok, "%var% (|{") && tok->next()->astOperand2() && tok->next()->astOperand2()->str() != ",") { Token* inTok = tok->next()->astOperand2(); const std::list& values = inTok->values(); const bool constValue = inTok->isNumber(); valueFlowForwardAssign(inTok, var, values, constValue, true, tokenlist, errorLogger, settings); } else if (Token::Match(tok, "%var% ;")) { ValueFlow::Value v(0); v.setKnown(); valueFlowForwardAssign(tok, var, {std::move(v)}, false, true, tokenlist, errorLogger, settings); } } } else if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (") && tok->astParent()->originalName() != "->") { std::vector vars = getVariables(tok); Token* ftok = tok->astParent()->tokAt(2); if (Token::simpleMatch(tok->astParent(), ". reset (")) { if (Token::simpleMatch(ftok, "( )")) { ValueFlow::Value v(0); v.setKnown(); valueFlowForwardAssign(ftok, tok, vars, {std::move(v)}, false, tokenlist, errorLogger, settings); } else { tok->removeValues(std::mem_fn(&ValueFlow::Value::isIntValue)); Token* inTok = ftok->astOperand2(); if (!inTok) continue; const std::list& values = inTok->values(); valueFlowForwardAssign(inTok, tok, vars, values, false, tokenlist, errorLogger, settings); } } else if (Token::simpleMatch(tok->astParent(), ". release ( )")) { const Token* parent = ftok->astParent(); bool hasParentReset = false; while (parent) { if (Token::Match(parent->tokAt(-2), ". release|reset (") && parent->tokAt(-2)->astOperand1()->exprId() == tok->exprId()) { hasParentReset = true; break; } parent = parent->astParent(); } if (hasParentReset) continue; ValueFlow::Value v(0); v.setKnown(); valueFlowForwardAssign(ftok, tok, vars, {std::move(v)}, false, tokenlist, errorLogger, settings); } else if (Token::simpleMatch(tok->astParent(), ". get ( )")) { ValueFlow::Value v = makeSymbolic(tok); setTokenValue(tok->astParent()->tokAt(2), std::move(v), settings); } } else if (Token::Match(tok->previous(), "%name%|> (|{") && astIsSmartPointer(tok) && astIsSmartPointer(tok->astOperand1())) { std::vector args = getArguments(tok); if (args.empty()) continue; for (const ValueFlow::Value& v : args.front()->values()) setTokenValue(tok, v, settings); } } } static Library::Container::Yield findIteratorYield(Token* tok, const Token** ftok, const Settings *settings) { auto yield = astContainerYield(tok, ftok); if (*ftok) return yield; if (!tok->astParent()) return yield; //begin/end free functions return astFunctionYield(tok->astParent()->previous(), settings, ftok); } static void valueFlowIterators(TokenList &tokenlist, const Settings *settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->scope()) continue; if (!tok->scope()->isExecutable()) continue; if (!astIsContainer(tok)) continue; Token* ftok = nullptr; const Library::Container::Yield yield = findIteratorYield(tok, const_cast(&ftok), settings); if (ftok) { ValueFlow::Value v(0); v.setKnown(); if (yield == Library::Container::Yield::START_ITERATOR) { v.valueType = ValueFlow::Value::ValueType::ITERATOR_START; setTokenValue(ftok->next(), std::move(v), settings); } else if (yield == Library::Container::Yield::END_ITERATOR) { v.valueType = ValueFlow::Value::ValueType::ITERATOR_END; setTokenValue(ftok->next(), std::move(v), settings); } } } } static std::list getIteratorValues(std::list values, const ValueFlow::Value::ValueKind* kind = nullptr) { values.remove_if([&](const ValueFlow::Value& v) { if (kind && v.valueKind != *kind) return true; return !v.isIteratorValue(); }); return values; } struct IteratorConditionHandler : SimpleConditionHandler { std::vector parse(const Token* tok, const Settings* /*settings*/) const override { Condition cond; if (Token::Match(tok, "==|!=")) { if (!tok->astOperand1() || !tok->astOperand2()) return {}; const ValueFlow::Value::ValueKind kind = ValueFlow::Value::ValueKind::Known; std::list values = getIteratorValues(tok->astOperand1()->values(), &kind); if (!values.empty()) { cond.vartok = tok->astOperand2(); } else { values = getIteratorValues(tok->astOperand2()->values(), &kind); if (!values.empty()) cond.vartok = tok->astOperand1(); } for (ValueFlow::Value& v:values) { v.setPossible(); v.assumeCondition(tok); } cond.true_values = values; cond.false_values = values; } return {std::move(cond)}; } }; static void valueFlowIteratorInfer(TokenList &tokenlist, const Settings *settings) { for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->scope()) continue; if (!tok->scope()->isExecutable()) continue; std::list values = getIteratorValues(tok->values()); values.remove_if([&](const ValueFlow::Value& v) { if (!v.isImpossible()) return true; if (!v.condition) return true; if (v.bound != ValueFlow::Value::Bound::Point) return true; if (v.isIteratorEndValue() && v.intvalue <= 0) return true; if (v.isIteratorStartValue() && v.intvalue >= 0) return true; return false; }); for (ValueFlow::Value& v:values) { v.setPossible(); if (v.isIteratorStartValue()) v.intvalue++; if (v.isIteratorEndValue()) v.intvalue--; setTokenValue(tok, std::move(v), settings); } } } static std::vector getContainerValues(const Token* tok) { std::vector values; if (tok) { std::copy_if(tok->values().cbegin(), tok->values().cend(), std::back_inserter(values), std::mem_fn(&ValueFlow::Value::isContainerSizeValue)); } return values; } static ValueFlow::Value makeContainerSizeValue(std::size_t s, bool known = true) { ValueFlow::Value value(s); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; if (known) value.setKnown(); return value; } static std::vector makeContainerSizeValue(const Token* tok, bool known = true) { if (tok->hasKnownIntValue()) return {makeContainerSizeValue(tok->values().front().intvalue, known)}; return {}; } static std::vector getContainerSizeFromConstructorArgs(const std::vector& args, const Library::Container* container, bool known) { if (astIsIntegral(args[0], false)) { // { count, i } or { count } if (args.size() == 1 || (args.size() > 1 && !astIsIntegral(args[1], false))) return {makeContainerSizeValue(args[0], known)}; } else if (astIsContainer(args[0]) && args.size() == 1) { // copy constructor return getContainerValues(args[0]); } else if (isIteratorPair(args)) { std::vector result = getContainerValues(args[0]); if (!result.empty()) return result; // (ptr, ptr + size) if (astIsPointer(args[0]) && args[0]->exprId() != 0) { // (ptr, ptr) is empty // TODO: Use lifetime values to check if it points to the same address if (args[0]->exprId() == args[1]->exprId()) return {makeContainerSizeValue(std::size_t{0}, known)}; // TODO: Insert iterator positions for pointers if (Token::simpleMatch(args[1], "+")) { nonneg int const eid = args[0]->exprId(); const Token* vartok = args[1]->astOperand1(); const Token* sizetok = args[1]->astOperand2(); if (sizetok->exprId() == eid) std::swap(vartok, sizetok); if (vartok->exprId() == eid && sizetok->hasKnownIntValue()) return {makeContainerSizeValue(sizetok, known)}; } } } else if (container->stdStringLike) { if (astIsPointer(args[0])) { // TODO: Try to read size of string literal { "abc" } if (args.size() == 2 && astIsIntegral(args[1], false)) // { char*, count } return {makeContainerSizeValue(args[1], known)}; } else if (astIsContainer(args[0])) { if (args.size() == 1) // copy constructor { str } return getContainerValues(args[0]); if (args.size() == 3) // { str, pos, count } return {makeContainerSizeValue(args[2], known)}; // TODO: { str, pos }, { ..., alloc } } } return {}; } static bool valueFlowIsSameContainerType(const ValueType& contType, const Token* tok, const Settings* settings) { if (!tok || !tok->valueType() || !tok->valueType()->containerTypeToken) return true; const ValueType tokType = ValueType::parseDecl(tok->valueType()->containerTypeToken, *settings); return contType.isTypeEqual(&tokType) || tokType.type == ValueType::Type::UNKNOWN_TYPE; } static std::vector getInitListSize(const Token* tok, const ValueType* valueType, const Settings* settings, bool known = true) { std::vector args = getArguments(tok); if (args.empty()) return {makeContainerSizeValue(std::size_t{0}, known)}; bool initList = true; // Try to disambiguate init list from constructor if (args.size() < 4) { initList = !isIteratorPair(args) && !(args.size() < 3 && astIsIntegral(args[0], false)); const Token* containerTypeToken = valueType->containerTypeToken; if (valueType->container->stdStringLike) { initList = astIsGenericChar(args[0]) && !astIsPointer(args[0]); } else if (containerTypeToken && settings) { ValueType vt = ValueType::parseDecl(containerTypeToken, *settings); if (vt.pointer > 0 && astIsPointer(args[0])) initList = true; else if (vt.type == ValueType::ITERATOR && astIsIterator(args[0])) initList = true; else if (vt.isIntegral() && astIsIntegral(args[0], false)) initList = true; else if (args.size() == 1 && valueFlowIsSameContainerType(vt, tok->astOperand2(), settings)) initList = false; // copy ctor } } if (!initList) return getContainerSizeFromConstructorArgs(args, valueType->container, known); return {makeContainerSizeValue(args.size(), known)}; } static std::vector getContainerSizeFromConstructor(const Token* tok, const ValueType* valueType, const Settings* settings, bool known = true) { std::vector args = getArguments(tok); if (args.empty()) return {makeContainerSizeValue(std::size_t{0}, known)}; // Init list in constructor if (args.size() == 1 && Token::simpleMatch(args[0], "{")) return getInitListSize(args[0], valueType, settings, known); return getContainerSizeFromConstructorArgs(args, valueType->container, known); } static void valueFlowContainerSetTokValue(TokenList& tokenlist, const Settings* settings, const Token* tok, Token* initList) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::TOK; value.tokvalue = initList; if (astIsContainerString(tok) && Token::simpleMatch(initList, "{") && Token::Match(initList->astOperand2(), "%str%")) { value.tokvalue = initList->astOperand2(); } value.setKnown(); Token* start = initList->link() ? initList->link() : initList->next(); if (tok->variable() && tok->variable()->isConst()) { valueFlowForwardConst(start, tok->variable()->scope()->bodyEnd, tok->variable(), {value}, settings); } else { valueFlowForward(start, tok, value, tokenlist, settings); } } static const Scope* getFunctionScope(const Scope* scope) { while (scope && scope->type != Scope::ScopeType::eFunction) scope = scope->nestedIn; return scope; } static MathLib::bigint valueFlowGetStrLength(const Token* tok) { if (tok->tokType() == Token::eString) return Token::getStrLength(tok); if (astIsGenericChar(tok) || tok->tokType() == Token::eChar) return 1; if (const ValueFlow::Value* v = tok->getKnownValue(ValueFlow::Value::ValueType::CONTAINER_SIZE)) return v->intvalue; if (const ValueFlow::Value* v = tok->getKnownValue(ValueFlow::Value::ValueType::TOK)) { if (v->tokvalue != tok) return valueFlowGetStrLength(v->tokvalue); } return 0; } static void valueFlowContainerSize(TokenList& tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger* /*errorLogger*/, const Settings* settings, const std::set& skippedFunctions) { // declaration for (const Variable *var : symboldatabase.variableList()) { if (!var) continue; if (!var->scope() || !var->scope()->bodyEnd || !var->scope()->bodyStart) continue; if (!var->valueType() || !var->valueType()->container) continue; if (!astIsContainer(var->nameToken())) continue; if (skippedFunctions.count(getFunctionScope(var->scope()))) continue; bool known = true; int size = 0; const bool nonLocal = !var->isLocal() || var->isPointer() || var->isReference() || var->isStatic(); bool constSize = var->isConst() && !nonLocal; bool staticSize = false; if (var->valueType()->container->size_templateArgNo >= 0) { staticSize = true; constSize = true; size = -1; if (var->dimensions().size() == 1) { const Dimension& dim = var->dimensions().front(); if (dim.known) { size = dim.num; } else if (dim.tok && dim.tok->hasKnownIntValue()) { size = dim.tok->values().front().intvalue; } } if (size < 0) continue; } if (!staticSize && nonLocal) continue; Token* nameToken = const_cast(var->nameToken()); if (nameToken->hasKnownValue(ValueFlow::Value::ValueType::CONTAINER_SIZE)) continue; if (!staticSize) { if (!Token::Match(nameToken, "%name% ;") && !(Token::Match(nameToken, "%name% {") && Token::simpleMatch(nameToken->next()->link(), "} ;")) && !Token::Match(nameToken, "%name% (")) continue; } if (nameToken->astTop() && Token::Match(nameToken->astTop()->previous(), "for|while")) known = !isVariableChanged(var, settings, true); std::vector values{ValueFlow::Value{size}}; values.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; if (known) values.back().setKnown(); if (!staticSize) { if (Token::simpleMatch(nameToken->next(), "{")) { Token* initList = nameToken->next(); valueFlowContainerSetTokValue(tokenlist, settings, nameToken, initList); values = getInitListSize(initList, var->valueType(), settings, known); } else if (Token::simpleMatch(nameToken->next(), "(")) { const Token* constructorArgs = nameToken->next(); values = getContainerSizeFromConstructor(constructorArgs, var->valueType(), settings, known); } } if (constSize) { valueFlowForwardConst(nameToken->next(), var->scope()->bodyEnd, var, values, settings); continue; } for (const ValueFlow::Value& value : values) { valueFlowForward(nameToken->next(), var->nameToken(), value, tokenlist, settings); } } // after assignment for (const Scope *functionScope : symboldatabase.functionScopes) { for (Token* tok = const_cast(functionScope->bodyStart); tok != functionScope->bodyEnd; tok = tok->next()) { if (Token::Match(tok, "%name%|;|{|} %var% = %str% ;")) { Token* containerTok = tok->next(); if (containerTok->exprId() == 0) continue; if (containerTok->valueType() && containerTok->valueType()->container && containerTok->valueType()->container->stdStringLike) { valueFlowContainerSetTokValue(tokenlist, settings, containerTok, containerTok->tokAt(2)); ValueFlow::Value value(Token::getStrLength(containerTok->tokAt(2))); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowForward(containerTok->next(), containerTok, value, tokenlist, settings); } } else if (Token::Match(tok->previous(), ">|return (|{") && astIsContainer(tok) && getLibraryContainer(tok)->size_templateArgNo < 0) { std::vector values; if (Token::simpleMatch(tok, "{")) { values = getInitListSize(tok, tok->valueType(), settings, true); ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::TOK; value.tokvalue = tok; value.setKnown(); values.push_back(value); } else if (Token::simpleMatch(tok, "(")) { const Token* constructorArgs = tok; values = getContainerSizeFromConstructor(constructorArgs, tok->valueType(), settings, true); } for (const ValueFlow::Value& value : values) setTokenValue(tok, value, settings); } else if (Token::Match(tok, "%name%|;|{|}|> %var% = {") && Token::simpleMatch(tok->linkAt(3), "} ;")) { Token* containerTok = tok->next(); if (containerTok->exprId() == 0) continue; if (astIsContainer(containerTok) && containerTok->valueType()->container->size_templateArgNo < 0) { std::vector values = getInitListSize(tok->tokAt(3), containerTok->valueType(), settings); valueFlowContainerSetTokValue(tokenlist, settings, containerTok, tok->tokAt(3)); for (const ValueFlow::Value& value : values) valueFlowForward(containerTok->next(), containerTok, value, tokenlist, settings); } } else if (Token::Match(tok, ". %name% (") && tok->astOperand1() && tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->container) { const Token* containerTok = tok->astOperand1(); if (containerTok->exprId() == 0) continue; const Library::Container::Action action = containerTok->valueType()->container->getAction(tok->strAt(1)); if (action == Library::Container::Action::CLEAR) { ValueFlow::Value value(0); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowForward(tok->next(), containerTok, value, tokenlist, settings); } else if (action == Library::Container::Action::RESIZE && tok->tokAt(2)->astOperand2() && tok->tokAt(2)->astOperand2()->hasKnownIntValue()) { ValueFlow::Value value(tok->tokAt(2)->astOperand2()->values().front()); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowForward(tok->linkAt(2), containerTok, value, tokenlist, settings); } else if (action == Library::Container::Action::PUSH && !isIteratorPair(getArguments(tok->tokAt(2)))) { ValueFlow::Value value(0); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setImpossible(); valueFlowForward(tok->linkAt(2), containerTok, value, tokenlist, settings); } } else if (Token::simpleMatch(tok, "+=") && astIsContainer(tok->astOperand1())) { const Token* containerTok = tok->astOperand1(); const Token* valueTok = tok->astOperand2(); MathLib::bigint size = valueFlowGetStrLength(valueTok); if (size == 0) continue; ValueFlow::Value value(size - 1); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.bound = ValueFlow::Value::Bound::Upper; value.setImpossible(); Token* next = nextAfterAstRightmostLeaf(tok); if (!next) next = tok->next(); valueFlowForward(next, containerTok, value, tokenlist, settings); } } } } struct ContainerConditionHandler : ConditionHandler { std::vector parse(const Token* tok, const Settings* settings) const override { std::vector conds; parseCompareEachInt(tok, [&](const Token* vartok, ValueFlow::Value true_value, ValueFlow::Value false_value) { vartok = settings->library.getContainerFromYield(vartok, Library::Container::Yield::SIZE); if (!vartok) return; true_value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; false_value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; Condition cond; cond.true_values.push_back(std::move(true_value)); cond.false_values.push_back(std::move(false_value)); cond.vartok = vartok; conds.push_back(std::move(cond)); }); if (!conds.empty()) return conds; const Token* vartok = nullptr; // Empty check if (tok->str() == "(") { vartok = settings->library.getContainerFromYield(tok, Library::Container::Yield::EMPTY); // TODO: Handle .size() if (!vartok) return {}; const Token *parent = tok->astParent(); while (parent) { if (Token::Match(parent, "%comp%")) return {}; parent = parent->astParent(); } ValueFlow::Value value(tok, 0LL); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; Condition cond; cond.true_values.emplace_back(value); cond.false_values.emplace_back(std::move(value)); cond.vartok = vartok; cond.inverted = true; return {std::move(cond)}; } // String compare if (Token::Match(tok, "==|!=")) { const Token *strtok = nullptr; if (Token::Match(tok->astOperand1(), "%str%")) { strtok = tok->astOperand1(); vartok = tok->astOperand2(); } else if (Token::Match(tok->astOperand2(), "%str%")) { strtok = tok->astOperand2(); vartok = tok->astOperand1(); } if (!strtok) return {}; if (!astIsContainer(vartok)) return {}; ValueFlow::Value value(tok, Token::getStrLength(strtok)); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; Condition cond; cond.false_values.emplace_back(value); cond.true_values.emplace_back(std::move(value)); cond.vartok = vartok; cond.impossible = false; return {std::move(cond)}; } return {}; } }; static void valueFlowDynamicBufferSize(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings) { auto getBufferSizeFromAllocFunc = [&](const Token* funcTok) -> MathLib::bigint { MathLib::bigint sizeValue = -1; const Library::AllocFunc* allocFunc = settings->library.getAllocFuncInfo(funcTok); if (!allocFunc) allocFunc = settings->library.getReallocFuncInfo(funcTok); if (!allocFunc || allocFunc->bufferSize == Library::AllocFunc::BufferSize::none) return sizeValue; const std::vector args = getArguments(funcTok); const Token* const arg1 = (args.size() >= allocFunc->bufferSizeArg1) ? args[allocFunc->bufferSizeArg1 - 1] : nullptr; const Token* const arg2 = (args.size() >= allocFunc->bufferSizeArg2) ? args[allocFunc->bufferSizeArg2 - 1] : nullptr; switch (allocFunc->bufferSize) { case Library::AllocFunc::BufferSize::none: break; case Library::AllocFunc::BufferSize::malloc: if (arg1 && arg1->hasKnownIntValue()) sizeValue = arg1->getKnownIntValue(); break; case Library::AllocFunc::BufferSize::calloc: if (arg1 && arg2 && arg1->hasKnownIntValue() && arg2->hasKnownIntValue()) sizeValue = arg1->getKnownIntValue() * arg2->getKnownIntValue(); break; case Library::AllocFunc::BufferSize::strdup: if (arg1 && arg1->hasKnownValue()) { const ValueFlow::Value& value = arg1->values().back(); if (value.isTokValue() && value.tokvalue->tokType() == Token::eString) sizeValue = Token::getStrLength(value.tokvalue) + 1; // Add one for the null terminator } break; } return sizeValue; }; auto getBufferSizeFromNew = [&](const Token* newTok) -> MathLib::bigint { MathLib::bigint sizeValue = -1, numElem = -1; if (newTok && newTok->astOperand1()) { // number of elements const Token* bracTok = nullptr, *typeTok = nullptr; if (newTok->astOperand1()->str() == "[") bracTok = newTok->astOperand1(); else if (Token::Match(newTok->astOperand1(), "(|{")) { if (newTok->astOperand1()->astOperand1() && newTok->astOperand1()->astOperand1()->str() == "[") bracTok = newTok->astOperand1()->astOperand1(); else typeTok = newTok->astOperand1()->astOperand1(); } else typeTok = newTok->astOperand1(); if (bracTok && bracTok->astOperand2() && bracTok->astOperand2()->hasKnownIntValue()) numElem = bracTok->astOperand2()->getKnownIntValue(); else if (Token::Match(typeTok, "%type%")) numElem = 1; } if (numElem >= 0 && newTok->astParent() && newTok->astParent()->isAssignmentOp()) { // size of the allocated type const Token* typeTok = newTok->astParent()->astOperand1(); // TODO: implement fallback for e.g. "auto p = new Type;" if (!typeTok || !typeTok->varId()) typeTok = newTok->astParent()->previous(); // hack for "int** z = ..." if (typeTok && typeTok->valueType()) { const MathLib::bigint typeSize = typeTok->valueType()->typeSize(settings->platform, typeTok->valueType()->pointer > 1); if (typeSize >= 0) sizeValue = numElem * typeSize; } } return sizeValue; }; for (const Scope *functionScope : symboldatabase.functionScopes) { for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) { if (!Token::Match(tok, "[;{}] %var% =")) continue; if (!tok->next()->variable()) continue; const Token *rhs = tok->tokAt(2)->astOperand2(); while (rhs && rhs->isCast()) rhs = rhs->astOperand2() ? rhs->astOperand2() : rhs->astOperand1(); if (!rhs) continue; const bool isNew = symboldatabase.isCPP() && rhs->str() == "new"; if (!isNew && !Token::Match(rhs->previous(), "%name% (")) continue; const MathLib::bigint sizeValue = isNew ? getBufferSizeFromNew(rhs) : getBufferSizeFromAllocFunc(rhs->previous()); if (sizeValue < 0) continue; ValueFlow::Value value(sizeValue); value.errorPath.emplace_back(tok->tokAt(2), "Assign " + tok->strAt(1) + ", buffer with size " + std::to_string(sizeValue)); value.valueType = ValueFlow::Value::ValueType::BUFFER_SIZE; value.setKnown(); valueFlowForward(const_cast(rhs), functionScope->bodyEnd, tok->next(), std::move(value), tokenlist, settings); } } } static bool getMinMaxValues(const ValueType *vt, const Platform &platform, MathLib::bigint &minValue, MathLib::bigint &maxValue) { if (!vt || !vt->isIntegral() || vt->pointer) return false; int bits; switch (vt->type) { case ValueType::Type::BOOL: bits = 1; break; case ValueType::Type::CHAR: bits = platform.char_bit; break; case ValueType::Type::SHORT: bits = platform.short_bit; break; case ValueType::Type::INT: bits = platform.int_bit; break; case ValueType::Type::LONG: bits = platform.long_bit; break; case ValueType::Type::LONGLONG: bits = platform.long_long_bit; break; default: return false; } if (bits == 1) { minValue = 0; maxValue = 1; } else if (bits < 62) { if (vt->sign == ValueType::Sign::UNSIGNED) { minValue = 0; maxValue = (1LL << bits) - 1; } else { minValue = -(1LL << (bits - 1)); maxValue = (1LL << (bits - 1)) - 1; } } else if (bits == 64) { if (vt->sign == ValueType::Sign::UNSIGNED) { minValue = 0; maxValue = LLONG_MAX; // todo max unsigned value } else { minValue = LLONG_MIN; maxValue = LLONG_MAX; } } else { return false; } return true; } static bool getMinMaxValues(const std::string &typestr, const Settings *settings, MathLib::bigint &minvalue, MathLib::bigint &maxvalue) { TokenList typeTokens(settings); std::istringstream istr(typestr+";"); if (!typeTokens.createTokens(istr)) return false; typeTokens.simplifyPlatformTypes(); typeTokens.simplifyStdType(); const ValueType &vt = ValueType::parseDecl(typeTokens.front(), *settings); return getMinMaxValues(&vt, settings->platform, minvalue, maxvalue); } static void valueFlowSafeFunctions(TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings) { for (const Scope *functionScope : symboldatabase.functionScopes) { if (!functionScope->bodyStart) continue; const Function *function = functionScope->function; if (!function) continue; const bool safe = function->isSafe(settings); const bool all = safe && settings->platform.type != Platform::Type::Unspecified; for (const Variable &arg : function->argumentList) { if (!arg.nameToken() || !arg.valueType()) continue; if (arg.valueType()->type == ValueType::Type::CONTAINER) { if (!safe) continue; std::list argValues; argValues.emplace_back(0); argValues.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; argValues.back().errorPath.emplace_back(arg.nameToken(), "Assuming " + arg.name() + " is empty"); argValues.back().safe = true; argValues.emplace_back(1000000); argValues.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; argValues.back().errorPath.emplace_back(arg.nameToken(), "Assuming " + arg.name() + " size is 1000000"); argValues.back().safe = true; for (const ValueFlow::Value &value : argValues) valueFlowForward(const_cast(functionScope->bodyStart), arg.nameToken(), value, tokenlist, settings); continue; } MathLib::bigint low, high; bool isLow = arg.nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::LOW, low); bool isHigh = arg.nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::HIGH, high); if (!isLow && !isHigh && !all) continue; const bool safeLow = !isLow; const bool safeHigh = !isHigh; if ((!isLow || !isHigh) && all) { MathLib::bigint minValue, maxValue; if (getMinMaxValues(arg.valueType(), settings->platform, minValue, maxValue)) { if (!isLow) low = minValue; if (!isHigh) high = maxValue; isLow = isHigh = true; } else if (arg.valueType()->type == ValueType::Type::FLOAT || arg.valueType()->type == ValueType::Type::DOUBLE || arg.valueType()->type == ValueType::Type::LONGDOUBLE) { std::list argValues; argValues.emplace_back(0); argValues.back().valueType = ValueFlow::Value::ValueType::FLOAT; argValues.back().floatValue = isLow ? low : -1E25; argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue)); argValues.back().safe = true; argValues.emplace_back(0); argValues.back().valueType = ValueFlow::Value::ValueType::FLOAT; argValues.back().floatValue = isHigh ? high : 1E25; argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue)); argValues.back().safe = true; valueFlowForward(const_cast(functionScope->bodyStart->next()), functionScope->bodyEnd, arg.nameToken(), argValues, tokenlist, settings); continue; } } std::list argValues; if (isLow) { argValues.emplace_back(low); argValues.back().errorPath.emplace_back(arg.nameToken(), std::string(safeLow ? "Safe checks: " : "") + "Assuming argument has value " + std::to_string(low)); argValues.back().safe = safeLow; } if (isHigh) { argValues.emplace_back(high); argValues.back().errorPath.emplace_back(arg.nameToken(), std::string(safeHigh ? "Safe checks: " : "") + "Assuming argument has value " + std::to_string(high)); argValues.back().safe = safeHigh; } if (!argValues.empty()) valueFlowForward(const_cast(functionScope->bodyStart->next()), functionScope->bodyEnd, arg.nameToken(), argValues, tokenlist, settings); } } } static void valueFlowUnknownFunctionReturn(TokenList &tokenlist, const Settings *settings) { if (settings->checkUnknownFunctionReturn.empty()) return; for (Token *tok = tokenlist.front(); tok; tok = tok->next()) { if (!tok->astParent() || tok->str() != "(" || !tok->previous()->isName()) continue; if (settings->checkUnknownFunctionReturn.find(tok->previous()->str()) == settings->checkUnknownFunctionReturn.end()) continue; std::vector unknownValues = settings->library.unknownReturnValues(tok->astOperand1()); if (unknownValues.empty()) continue; // Get min/max values for return type const std::string &typestr = settings->library.returnValueType(tok->previous()); MathLib::bigint minvalue, maxvalue; if (!getMinMaxValues(typestr, settings, minvalue, maxvalue)) continue; for (MathLib::bigint value : unknownValues) { if (value < minvalue) value = minvalue; else if (value > maxvalue) value = maxvalue; setTokenValue(tok, ValueFlow::Value(value), settings); } } } static void valueFlowDebug(TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) { if (!settings->debugnormal && !settings->debugwarnings) return; for (Token* tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->getTokenDebug() != TokenDebug::ValueFlow) continue; if (tok->astParent() && tok->astParent()->getTokenDebug() == TokenDebug::ValueFlow) continue; for (const ValueFlow::Value& v : tok->values()) { std::string msg = "The value is " + debugString(v); ErrorPath errorPath = v.errorPath; errorPath.insert(errorPath.end(), v.debugPath.cbegin(), v.debugPath.cend()); errorPath.emplace_back(tok, ""); errorLogger->reportErr({errorPath, &tokenlist, Severity::debug, "valueFlow", msg, CWE{0}, Certainty::normal}); } } } const ValueFlow::Value *ValueFlow::valueFlowConstantFoldAST(Token *expr, const Settings *settings) { if (expr && expr->values().empty()) { valueFlowConstantFoldAST(expr->astOperand1(), settings); valueFlowConstantFoldAST(expr->astOperand2(), settings); valueFlowSetConstantValue(expr, settings, true /* TODO: this is a guess */); } return expr && expr->hasKnownValue() ? &expr->values().front() : nullptr; } struct ValueFlowState { explicit ValueFlowState(TokenList& tokenlist, SymbolDatabase& symboldatabase, ErrorLogger* errorLogger = nullptr, const Settings* settings = nullptr) : tokenlist(tokenlist), symboldatabase(symboldatabase), errorLogger(errorLogger), settings(settings) {} TokenList& tokenlist; SymbolDatabase& symboldatabase; ErrorLogger* errorLogger = nullptr; const Settings* settings = nullptr; std::set skippedFunctions; }; struct ValueFlowPass { ValueFlowPass() = default; ValueFlowPass(const ValueFlowPass&) = default; // Name of pass virtual const char* name() const = 0; // Run the pass virtual void run(const ValueFlowState& state) const = 0; // Returns true if pass needs C++ virtual bool cpp() const = 0; virtual ~ValueFlowPass() noexcept = default; }; struct ValueFlowPassRunner { using Clock = std::chrono::steady_clock; using TimePoint = std::chrono::time_point; explicit ValueFlowPassRunner(ValueFlowState state, TimerResultsIntf* timerResults = nullptr) : state(std::move(state)), stop(TimePoint::max()), timerResults(timerResults) { setSkippedFunctions(); setStopTime(); } bool run_once(std::initializer_list> passes) const { return std::any_of(passes.begin(), passes.end(), [&](const ValuePtr& pass) { return run(pass); }); } bool run(std::initializer_list> passes) const { std::size_t values = 0; std::size_t n = state.settings->valueFlowMaxIterations; while (n > 0 && values != getTotalValues()) { values = getTotalValues(); if (std::any_of(passes.begin(), passes.end(), [&](const ValuePtr& pass) { return run(pass); })) return true; --n; } if (state.settings->debugwarnings) { if (n == 0 && values != getTotalValues()) { ErrorMessage::FileLocation loc; loc.setfile(state.tokenlist.getFiles()[0]); ErrorMessage errmsg({std::move(loc)}, emptyString, Severity::debug, "ValueFlow maximum iterations exceeded", "valueFlowMaxIterations", Certainty::normal); state.errorLogger->reportErr(errmsg); } } return false; } bool run(const ValuePtr& pass) const { auto start = Clock::now(); if (start > stop) return true; if (!state.tokenlist.isCPP() && pass->cpp()) return false; if (timerResults) { Timer t(pass->name(), state.settings->showtime, timerResults); pass->run(state); } else { pass->run(state); } return false; } std::size_t getTotalValues() const { std::size_t n = 1; for (Token* tok = state.tokenlist.front(); tok; tok = tok->next()) n += tok->values().size(); return n; } void setSkippedFunctions() { if (state.settings->performanceValueFlowMaxIfCount > 0) { for (const Scope* functionScope : state.symboldatabase.functionScopes) { int countIfScopes = 0; std::vector scopes{functionScope}; while (!scopes.empty()) { const Scope* s = scopes.back(); scopes.pop_back(); for (const Scope* s2 : s->nestedList) { scopes.emplace_back(s2); if (s2->type == Scope::ScopeType::eIf) ++countIfScopes; } } if (countIfScopes > state.settings->performanceValueFlowMaxIfCount) { state.skippedFunctions.emplace(functionScope); if (state.settings->severity.isEnabled(Severity::information)) { const std::string& functionName = functionScope->className; const std::list callstack( 1, ErrorMessage::FileLocation(functionScope->bodyStart, &state.tokenlist)); const ErrorMessage errmsg(callstack, state.tokenlist.getSourceFilePath(), Severity::information, "ValueFlow analysis is limited in " + functionName + ". Use --check-level=exhaustive if full analysis is wanted.", "checkLevelNormal", Certainty::normal); state.errorLogger->reportErr(errmsg); } } } } } void setStopTime() { if (state.settings->performanceValueFlowMaxTime >= 0) stop = Clock::now() + std::chrono::seconds{state.settings->performanceValueFlowMaxTime}; } ValueFlowState state; TimePoint stop; TimerResultsIntf* timerResults; }; template struct ValueFlowPassAdaptor : ValueFlowPass { const char* mName = nullptr; bool mCPP = false; F mRun; ValueFlowPassAdaptor(const char* pname, bool pcpp, F prun) : mName(pname), mCPP(pcpp), mRun(prun) {} const char* name() const override { return mName; } void run(const ValueFlowState& state) const override { mRun(state.tokenlist, state.symboldatabase, state.errorLogger, state.settings, state.skippedFunctions); } bool cpp() const override { return mCPP; } }; template ValueFlowPassAdaptor makeValueFlowPassAdaptor(const char* name, bool cpp, F run) { return {name, cpp, run}; } #define VALUEFLOW_ADAPTOR(cpp, ...) \ makeValueFlowPassAdaptor(#__VA_ARGS__, \ cpp, \ [](TokenList& tokenlist, \ SymbolDatabase& symboldatabase, \ ErrorLogger* errorLogger, \ const Settings* settings, \ const std::set& skippedFunctions) { \ (void)tokenlist; \ (void)symboldatabase; \ (void)errorLogger; \ (void)settings; \ (void)skippedFunctions; \ __VA_ARGS__; \ }) #define VFA(...) VALUEFLOW_ADAPTOR(false, __VA_ARGS__) #define VFA_CPP(...) VALUEFLOW_ADAPTOR(true, __VA_ARGS__) void ValueFlow::setValues(TokenList& tokenlist, SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings* settings, TimerResultsIntf* timerResults) { for (Token* tok = tokenlist.front(); tok; tok = tok->next()) tok->clearValueFlow(); // commas in init.. for (Token* tok = tokenlist.front(); tok; tok = tok->next()) { if (tok->str() != "{" || !tok->astOperand1()) continue; for (Token* tok2 = tok->next(); tok2 != tok->link(); tok2 = tok2->next()) { if (tok2->link() && Token::Match(tok2, "[{[(<]")) tok2 = tok2->link(); else if (tok2->str() == ",") tok2->isInitComma(true); } } ValueFlowPassRunner runner{ValueFlowState{tokenlist, symboldatabase, errorLogger, settings}, timerResults}; runner.run_once({ VFA(valueFlowEnumValue(symboldatabase, settings)), VFA(valueFlowNumber(tokenlist, settings)), VFA(valueFlowString(tokenlist, settings)), VFA(valueFlowArray(tokenlist, settings)), VFA(valueFlowUnknownFunctionReturn(tokenlist, settings)), VFA(valueFlowGlobalConstVar(tokenlist, settings)), VFA(valueFlowEnumValue(symboldatabase, settings)), VFA(valueFlowNumber(tokenlist, settings)), VFA(valueFlowGlobalStaticVar(tokenlist, settings)), VFA(valueFlowPointerAlias(tokenlist, settings)), VFA(valueFlowLifetime(tokenlist, errorLogger, settings)), VFA(valueFlowSymbolic(tokenlist, symboldatabase, settings)), VFA(valueFlowBitAnd(tokenlist, settings)), VFA(valueFlowSameExpressions(tokenlist, settings)), VFA(valueFlowConditionExpressions(tokenlist, symboldatabase, errorLogger, *settings)), }); runner.run({ VFA(valueFlowImpossibleValues(tokenlist, settings)), VFA(valueFlowSymbolicOperators(symboldatabase, settings)), VFA(valueFlowCondition(SymbolicConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)), VFA(valueFlowSymbolicInfer(symboldatabase, settings)), VFA(valueFlowArrayBool(tokenlist, settings)), VFA(valueFlowArrayElement(tokenlist, settings)), VFA(valueFlowRightShift(tokenlist, settings)), VFA(valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)), VFA_CPP(valueFlowAfterSwap(tokenlist, symboldatabase, errorLogger, settings)), VFA(valueFlowCondition(SimpleConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)), VFA(valueFlowInferCondition(tokenlist, settings)), VFA(valueFlowSwitchVariable(tokenlist, symboldatabase, errorLogger, settings)), VFA(valueFlowForLoop(tokenlist, symboldatabase, errorLogger, settings)), VFA(valueFlowSubFunction(tokenlist, symboldatabase, errorLogger, *settings)), VFA(valueFlowFunctionReturn(tokenlist, errorLogger, settings)), VFA(valueFlowLifetime(tokenlist, errorLogger, settings)), VFA(valueFlowFunctionDefaultParameter(tokenlist, symboldatabase, settings)), VFA(valueFlowUninit(tokenlist, settings)), VFA_CPP(valueFlowAfterMove(tokenlist, symboldatabase, settings)), VFA_CPP(valueFlowSmartPointer(tokenlist, errorLogger, settings)), VFA_CPP(valueFlowIterators(tokenlist, settings)), VFA_CPP( valueFlowCondition(IteratorConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)), VFA_CPP(valueFlowIteratorInfer(tokenlist, settings)), VFA_CPP(valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)), VFA_CPP( valueFlowCondition(ContainerConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)), VFA(valueFlowSafeFunctions(tokenlist, symboldatabase, settings)), }); runner.run_once({ VFA(valueFlowDynamicBufferSize(tokenlist, symboldatabase, settings)), VFA(valueFlowDebug(tokenlist, errorLogger, settings)), }); } std::string ValueFlow::eitherTheConditionIsRedundant(const Token *condition) { if (!condition) return "Either the condition is redundant"; if (condition->str() == "case") { std::string expr; for (const Token *tok = condition; tok && tok->str() != ":"; tok = tok->next()) { expr += tok->str(); if (Token::Match(tok, "%name%|%num% %name%|%num%")) expr += ' '; } return "Either the switch case '" + expr + "' is redundant"; } return "Either the condition '" + condition->expressionString() + "' is redundant"; } const ValueFlow::Value* ValueFlow::findValue(const std::list& values, const Settings* settings, const std::function &pred) { const ValueFlow::Value* ret = nullptr; for (const ValueFlow::Value& v : values) { if (pred(v)) { if (!ret || ret->isInconclusive() || (ret->condition && !v.isInconclusive())) ret = &v; if (!ret->isInconclusive() && !ret->condition) break; } } if (settings && ret) { if (ret->isInconclusive() && !settings->certainty.isEnabled(Certainty::inconclusive)) return nullptr; if (ret->condition && !settings->severity.isEnabled(Severity::warning)) return nullptr; } return ret; } // TODO: returns a single value at most - no need for std::vector static std::vector isOutOfBoundsImpl(const ValueFlow::Value& size, const Token* indexTok, bool condition) { if (!indexTok) return {}; const ValueFlow::Value* indexValue = indexTok->getMaxValue(condition, size.path); if (!indexValue) return {}; if (indexValue->intvalue >= size.intvalue) return {*indexValue}; if (!condition) return {}; // TODO: Use a better way to decide if the variable in unconstrained if (!indexTok->variable() || !indexTok->variable()->isArgument()) return {}; if (std::any_of(indexTok->values().cbegin(), indexTok->values().cend(), [&](const ValueFlow::Value& v) { return v.isSymbolicValue() && v.isPossible() && v.bound == ValueFlow::Value::Bound::Upper; })) return {}; if (indexValue->bound != ValueFlow::Value::Bound::Lower) return {}; if (size.bound == ValueFlow::Value::Bound::Lower) return {}; // Checking for underflow doesn't mean it could be out of bounds if (indexValue->intvalue == 0) return {}; ValueFlow::Value value = inferCondition(">=", indexTok, indexValue->intvalue); if (!value.isKnown()) return {}; if (value.intvalue == 0) return {}; value.intvalue = size.intvalue; value.bound = ValueFlow::Value::Bound::Lower; return {std::move(value)}; } // TODO: return single value at most - no need for std::vector std::vector ValueFlow::isOutOfBounds(const Value& size, const Token* indexTok, bool possible) { ValueFlow::Value inBoundsValue = inferCondition("<", indexTok, size.intvalue); if (inBoundsValue.isKnown() && inBoundsValue.intvalue != 0) return {}; std::vector result = isOutOfBoundsImpl(size, indexTok, false); if (!result.empty()) return result; if (!possible) return result; return isOutOfBoundsImpl(size, indexTok, true); }