/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2021 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 "checkuninitvar.h" #include "config.h" #include "errorlogger.h" #include "errortypes.h" #include "forwardanalyzer.h" #include "library.h" #include "mathlib.h" #include "path.h" #include "platform.h" #include "programmemory.h" #include "reverseanalyzer.h" #include "settings.h" #include "standards.h" #include "symboldatabase.h" #include "token.h" #include "tokenlist.h" #include "utils.h" #include "valueptr.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #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) + ":" + MathLib::toString(line) + ":" + function + " bailout: " + what, type, Certainty::normal); errorLogger->reportErr(errmsg); } #if (defined __cplusplus) && __cplusplus >= 201103L #define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __func__) #elif (defined __GNUC__) || (defined __clang__) || (defined _MSC_VER) #define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __FUNCTION__) #else #define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, "(valueFlow)") #endif #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 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 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 setConditionalValues(const Token* tok, bool lhs, MathLib::bigint value, ValueFlow::Value& true_value, ValueFlow::Value& false_value) { if (Token::Match(tok, "==|!=|>=|<=")) { true_value = ValueFlow::Value{tok, value}; const char* greaterThan = ">="; const char* lessThan = "<="; if (lhs) std::swap(greaterThan, lessThan); if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) { false_value = ValueFlow::Value{tok, value - 1}; } else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) { false_value = ValueFlow::Value{tok, value + 1}; } else { false_value = ValueFlow::Value{tok, value}; } } else { const char* greaterThan = ">"; const char* lessThan = "<"; if (lhs) std::swap(greaterThan, lessThan); if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) { true_value = ValueFlow::Value{tok, value + 1}; false_value = ValueFlow::Value{tok, value}; } else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) { true_value = ValueFlow::Value{tok, value - 1}; false_value = ValueFlow::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(); } const Token *parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value, const std::function(const Token*)>& evaluate) { if (!tok->astOperand1() || !tok->astOperand2()) return nullptr; 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(); } if (!value1.empty()) { if (isSaturated(value1.front())) return nullptr; setConditionalValues(tok, true, value1.front(), true_value, false_value); return tok->astOperand2(); } else if (!value2.empty()) { if (isSaturated(value2.front())) return nullptr; setConditionalValues(tok, false, value2.front(), true_value, false_value); return tok->astOperand1(); } } return nullptr; } const Token *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, TokenList * tokenlist, 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 (tokenlist && tokenlist->getSettings()->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 void 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.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) { // TODO: This might be a generic utility function? if (!parent || parent->str() != "(") return nullptr; if (!parent->astOperand2() && Token::Match(parent,"( %name%")) 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; } static bool isComputableValue(const Token* parent, const ValueFlow::Value& value) { const bool noninvertible = parent->isComparisonOp() || Token::Match(parent, "%|/|&|%or%"); 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() || value.tokvalue->tokType() != Token::eString)) return false; return true; } template static bool isEqual(T x, T y) { return x == y; } template<> bool isEqual(double x, double y) { const double diff = (x > y) ? x - y : y - x; return !((diff / 2) < diff); } template static bool isZero(T x) { return isEqual(x, T(0)); } template static R calculate(const std::string& s, const T& x, const T& y, bool* error = nullptr) { auto wrap = [](T z) { return R{z}; }; switch (MathLib::encodeMultiChar(s)) { case '+': return wrap(x + y); case '-': return wrap(x - y); case '*': return wrap(x * y); case '/': if (isZero(y)) { if (error) *error = true; return R{}; } return wrap(x / y); case '%': if (isZero(y)) { if (error) *error = true; return R{}; } return wrap(MathLib::bigint(x) % MathLib::bigint(y)); case '&': return wrap(MathLib::bigint(x) & MathLib::bigint(y)); case '|': return wrap(MathLib::bigint(x) | MathLib::bigint(y)); case '^': return wrap(MathLib::bigint(x) ^ MathLib::bigint(y)); case '>': return wrap(x > y); case '<': return wrap(x < y); case '<<': if (y >= sizeof(MathLib::bigint) * 8) { if (error) *error = true; return R{}; } return wrap(MathLib::bigint(x) << MathLib::bigint(y)); case '>>': if (y >= sizeof(MathLib::bigint) * 8) { if (error) *error = true; return R{}; } return wrap(MathLib::bigint(x) >> MathLib::bigint(y)); case '&&': return wrap(!isZero(x) && !isZero(y)); case '||': return wrap(!isZero(x) || !isZero(y)); case '==': return wrap(isEqual(x, y)); case '!=': return wrap(!isEqual(x, y)); case '>=': return wrap(x >= y); case '<=': return wrap(x <= y); } throw InternalError(nullptr, "Unknown operator: " + s); } template static T calculate(const std::string& s, const T& x, const T& y, bool* error = nullptr) { return calculate(s, x, y, error); } /** Set token value for cast */ static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings); static bool isCompatibleValues(const ValueFlow::Value& value1, const ValueFlow::Value& value2) { 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; size_t n1 = ValueFlow::getSizeOf(*vt1, settings); 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) { // 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 (!tok->addValue(value)) return; if (value.path < 0) return; Token *parent = tok->astParent(); if (!parent) return; if (Token::simpleMatch(parent, "=") && astIsRHS(tok) && !value.isLifetimeValue()) { setTokenValue(parent, value, settings); return; } if (value.isContainerSizeValue()) { // .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, result, settings); } } } else if (Token::Match(parent, ". %name% (") && parent->astParent() == parent->tokAt(2) && parent->astOperand1() && parent->astOperand1()->valueType()) { const Library::Container *c = parent->astOperand1()->valueType()->container; const Library::Container::Yield yields = c ? c->getYield(parent->strAt(1)) : Library::Container::Yield::NO_YIELD; if (yields == Library::Container::Yield::SIZE) { ValueFlow::Value v(value); v.valueType = ValueFlow::Value::ValueType::INT; setTokenValue(parent->astParent(), v, settings); } else if (yields == Library::Container::Yield::EMPTY) { ValueFlow::Value v(value); v.intvalue = !v.intvalue; v.valueType = ValueFlow::Value::ValueType::INT; setTokenValue(parent->astParent(), v, settings); } } return; } if (value.isLifetimeValue()) { if (!isLifetimeBorrowed(parent, settings)) return; if (value.lifetimeKind == ValueFlow::Value::LifetimeKind::Iterator && astIsIterator(parent)) { setTokenValue(parent,value,settings); } else if (astIsPointer(tok) && astIsPointer(parent) && !parent->isUnaryOp("*") && (parent->isArithmeticalOp() || parent->isCast())) { setTokenValue(parent,value,settings); } return; } if (value.isUninitValue()) { ValueFlow::Value pvalue = value; if (parent->isUnaryOp("&")) { pvalue.indirect++; setTokenValue(parent, pvalue, settings); } else if (Token::Match(parent, ". %var%") && parent->astOperand1() == tok) { if (parent->originalName() == "->" && pvalue.indirect > 0) pvalue.indirect--; setTokenValue(parent->astOperand2(), 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(), pvalue, settings); } else if (parent->isUnaryOp("*") && pvalue.indirect > 0) { pvalue.indirect--; setTokenValue(parent, pvalue, settings); } return; } // cast.. if (const Token *castType = getCastTypeStartToken(parent)) { if (((tok->valueType() == nullptr && value.isImpossible()) || astIsPointer(tok)) && value.valueType == ValueFlow::Value::ValueType::INT && 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.begin(), values.end(), value) != values.end()) setTokenValue(parent, value, settings); } } else { // is condition only depending on 1 variable? 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(); if (varId) v.varId = varId; 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 = parent->isComparisonOp() || Token::Match(parent, "%|/|&|%or%"); // 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, "[&*]") && value.isKnown() && value.isIntValue() && value.intvalue==0) { setTokenValue(parent, value, settings); return; } // known result when a operand is true. if (Token::simpleMatch(parent, "&&") && value.isKnown() && value.isIntValue() && value.intvalue==0) { setTokenValue(parent, value, settings); return; } // known result when a operand is false. if (Token::simpleMatch(parent, "||") && value.isKnown() && value.isIntValue() && value.intvalue!=0) { setTokenValue(parent, 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); const double floatValue1 = value1.isIntValue() ? value1.intvalue : value1.floatValue; const double floatValue2 = value2.isIntValue() ? value2.intvalue : value2.floatValue; const bool isFloat = value1.isFloatValue() || value2.isFloatValue(); if (isFloat && Token::Match(parent, "&|^|%|<<|>>|%or%")) continue; if (Token::Match(parent, "<<|>>") && !(value1.intvalue >= 0 && value2.intvalue >= 0 && value2.intvalue < MathLib::bigint_bits)) continue; if (Token::Match(parent, "/|%") && isZero(floatValue2)) 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()) { result.intvalue = calculate(parent->str(), value1.intvalue, value2.intvalue); } else { continue; } setTokenValue(parent, result, settings); } else if (Token::Match(parent, "%comp%")) { if (!isFloat && !value1.isIntValue() && !value2.isIntValue()) continue; if (isFloat) result.intvalue = calculate(parent->str(), floatValue1, floatValue2); else result.intvalue = calculate(parent->str(), value1.intvalue, value2.intvalue); setTokenValue(parent, result, settings); } else if (Token::Match(parent, "%op%")) { if (value1.isTokValue() || value2.isTokValue()) break; if (isFloat) { result.valueType = ValueFlow::Value::ValueType::FLOAT; result.floatValue = calculate(parent->str(), floatValue1, floatValue2); } else { result.intvalue = calculate(parent->str(), value1.intvalue, value2.intvalue); } // 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); v.intvalue = !v.intvalue; setTokenValue(parent, 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 (settings && tok->valueType() && tok->valueType()->sign == ValueType::Sign::UNSIGNED && tok->valueType()->pointer == 0) { if (tok->valueType()->type == ValueType::Type::INT) bits = settings->int_bit; else if (tok->valueType()->type == ValueType::Type::LONG) bits = settings->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, v, settings); } } // increment else if (parent->str() == "++") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue() && !val.isFloatValue()) continue; ValueFlow::Value v(val); if (parent == tok->previous()) { if (v.isIntValue()) v.intvalue = v.intvalue + 1; else v.floatValue = v.floatValue + 1.0; } setTokenValue(parent, v, settings); } } // decrement else if (parent->str() == "--") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue() && !val.isFloatValue()) continue; ValueFlow::Value v(val); if (parent == tok->previous()) { if (v.isIntValue()) v.intvalue = v.intvalue - 1; else v.floatValue = v.floatValue - 1.0; } setTokenValue(parent, v, settings); } } // Array element else if (parent->str() == "[" && parent->isBinaryOp()) { for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) { if (!value1.isTokValue()) continue; for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) { if (!value2.isIntValue()) continue; if (value1.varId == 0 || value2.varId == 0 || (value1.varId == value2.varId && value1.varvalue == value2.varvalue)) { ValueFlow::Value result(0); result.condition = value1.condition ? value1.condition : value2.condition; result.setInconclusive(value1.isInconclusive() | value2.isInconclusive()); result.varId = (value1.varId != 0) ? value1.varId : value2.varId; result.varvalue = (result.varId == value1.varId) ? value1.intvalue : value2.intvalue; if (value1.valueKind == value2.valueKind) result.valueKind = value1.valueKind; if (value1.tokvalue->tokType() == Token::eString) { const std::string s = value1.tokvalue->strValue(); const MathLib::bigint index = value2.intvalue; if (index == s.size()) { result.intvalue = 0; setTokenValue(parent, result, settings); } else if (index >= 0 && index < s.size()) { result.intvalue = s[index]; setTokenValue(parent, result, settings); } } else if (value1.tokvalue->str() == "{") { MathLib::bigint index = value2.intvalue; const Token *element = value1.tokvalue->next(); while (index > 0 && element->str() != "}") { if (element->str() == ",") --index; if (Token::Match(element, "[{}()[]]")) break; element = element->next(); } if (Token::Match(element, "%num% [,}]")) { result.intvalue = MathLib::toLongNumber(element->str()); setTokenValue(parent, result, settings); } } } } } } else if (Token::Match(parent, ":: %name%") && parent->astOperand2() == tok) { setTokenValue(parent, value, 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->char_bit), settings); else if (valueType.type == ValueType::Type::SHORT) setTokenValue(parent, castValue(value, valueType.sign, settings->short_bit), settings); else if (valueType.type == ValueType::Type::INT) setTokenValue(parent, castValue(value, valueType.sign, settings->int_bit), settings); else if (valueType.type == ValueType::Type::LONG) setTokenValue(parent, castValue(value, valueType.sign, settings->long_bit), settings); else if (valueType.type == ValueType::Type::LONGLONG) setTokenValue(parent, castValue(value, valueType.sign, settings->long_long_bit), settings); else if (value.isIntValue()) { const long long charMax = settings->signedCharMax(); const long long charMin = settings->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); if (valueType.pointer > 0) return settings->sizeof_pointer; if (valueType.type == ValueType::Type::BOOL || valueType.type == ValueType::Type::CHAR) return 1; if (valueType.type == ValueType::Type::SHORT) return settings->sizeof_short; if (valueType.type == ValueType::Type::INT) return settings->sizeof_int; if (valueType.type == ValueType::Type::LONG) return settings->sizeof_long; if (valueType.type == ValueType::Type::LONGLONG) return settings->sizeof_long_long; if (valueType.type == ValueType::Type::WCHAR_T) return settings->sizeof_wchar_t; return 0; } size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings *settings) { if (vt.pointer) return settings->sizeof_pointer; if (vt.type == ValueType::Type::CHAR) return 1; if (vt.type == ValueType::Type::SHORT) return settings->sizeof_short; if (vt.type == ValueType::Type::WCHAR_T) return settings->sizeof_wchar_t; if (vt.type == ValueType::Type::INT) return settings->sizeof_int; if (vt.type == ValueType::Type::LONG) return settings->sizeof_long; if (vt.type == ValueType::Type::LONGLONG) return settings->sizeof_long_long; if (vt.type == ValueType::Type::FLOAT) return settings->sizeof_float; if (vt.type == ValueType::Type::DOUBLE) return settings->sizeof_double; if (vt.type == ValueType::Type::LONGDOUBLE) return settings->sizeof_long_double; return 0; } // 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 { ValueFlow::Value value(MathLib::toLongNumber(tok->str())); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, 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, value, settings); } else if (tok->enumerator() && tok->enumerator()->value_known) { ValueFlow::Value value(tok->enumerator()->value); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, value, settings); } else if (tok->str() == "NULL" || (cpp && tok->str() == "nullptr")) { ValueFlow::Value value(0); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, 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()->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(), value, settings); return tok->linkAt(1); } } const Token *tok2 = tok->tokAt(2); // skip over tokens to find variable or type while (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->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(tok->next(), value, settings); } } else if (tok2->enumerator() && tok2->enumerator()->scope) { long long size = settings->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->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(tok, value, settings); setTokenValue(tok->next(), value, settings); } else if (tok2->type() && tok2->type()->isEnumType()) { long long size = settings->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->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(tok, value, settings); setTokenValue(tok->next(), value, settings); } else if (Token::Match(tok, "sizeof ( %var% ) / sizeof (") && tok->next()->astParent() == tok->tokAt(4)) { // Get number of elements in array const Token *sz1 = tok->tokAt(2); const Token *sz2 = tok->tokAt(7); const nonneg int varid1 = sz1->varId(); if (varid1 && sz1->variable() && sz1->variable()->isArray() && !sz1->variable()->dimensions().empty() && sz1->variable()->dimensionKnown(0) && (Token::Match(sz2, "* %varid% )", varid1) || Token::Match(sz2, "%varid% [ 0 ] )", varid1))) { ValueFlow::Value value(sz1->variable()->dimension(0)); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(tok->tokAt(4), 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->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->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(tok, value, settings); setTokenValue(tok->next(), value, settings); } } } else if (tok2->tokType() == Token::eString) { size_t sz = Token::getStrSize(tok2, settings); if (sz > 0) { ValueFlow::Value value(sz); value.setKnown(); setTokenValue(const_cast(tok->next()), 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->sizeof_wchar_t; else if ((tok2->isCChar() && !cpp) || (tok2->isCMultiChar())) sz = settings->sizeof_int; else sz = 1; if (sz > 0) { ValueFlow::Value value(sz); value.setKnown(); setTokenValue(tok->next(), value, settings); } } else if (!tok2->type()) { const ValueType &vt = ValueType::parseDecl(tok2,settings); const size_t sz = ValueFlow::getSizeOf(vt, settings); if (sz > 0) { ValueFlow::Value value(sz); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(tok->next(), value, settings); } } // skip over enum tok = tok->linkAt(1); } return tok->next(); } static void valueFlowNumber(TokenList *tokenlist) { for (Token *tok = tokenlist->front(); tok;) { tok = valueFlowSetConstantValue(tok, tokenlist->getSettings(), 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, value, tokenlist->getSettings()); } 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(), value, tokenlist->getSettings()); } } } } static void valueFlowString(TokenList *tokenlist) { 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, strvalue, tokenlist->getSettings()); } } } static void valueFlowArray(TokenList *tokenlist) { 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, value, tokenlist->getSettings()); } // pointer = array else if (tok->variable() && tok->variable()->isArray() && Token::simpleMatch(tok->astParent(), "=") && tok == tok->astParent()->astOperand2() && 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, value, tokenlist->getSettings()); } continue; } if (Token::Match(tok, "const %type% %var% [ %num%| ] = {")) { const Token *vartok = tok->tokAt(2); const Token *rhstok = vartok->next()->link()->tokAt(2); constantArrays[vartok->varId()] = rhstok; tok = rhstok->link(); continue; } else if (Token::Match(tok, "const char %var% [ %num%| ] = %str% ;")) { const Token *vartok = tok->tokAt(2); const 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) { for (Token *tok = tokenlist->front(); tok; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; const Variable *var = nullptr; bool known = false; std::list::const_iterator val = std::find_if(tok->values().begin(), tok->values().end(), 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, value, tokenlist->getSettings()); } } } static void valueFlowPointerAlias(TokenList *tokenlist) { 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, value, tokenlist->getSettings()); } } static void valueFlowUninitPointerAliasDeref(TokenList *tokenlist) { for (Token *tok = tokenlist->front(); tok; tok = tok->next()) { if (!tok->isUnaryOp("*")) continue; if (!astIsPointer(tok->astOperand1())) continue; const Token* lifeTok = nullptr; ErrorPath errorPath; for (const ValueFlow::Value& v:tok->astOperand1()->values()) { if (!v.isLocalLifetimeValue()) continue; lifeTok = v.tokvalue; errorPath = v.errorPath; } if (!lifeTok) continue; if (lifeTok->varId() == 0) continue; const Variable * var = lifeTok->variable(); if (!var) continue; if (!var->isConst() && isVariableChanged(lifeTok->next(), tok, lifeTok->varId(), !var->isLocal(), tokenlist->getSettings(), tokenlist->isCPP())) continue; for (const ValueFlow::Value& v:lifeTok->values()) { // Forward uninit values since not all values can be forwarded directly if (!v.isUninitValue()) continue; ValueFlow::Value value = v; value.errorPath.insert(value.errorPath.begin(), errorPath.begin(), errorPath.end()); setTokenValue(tok, value, tokenlist->getSettings()); } } } static void valueFlowBitAnd(TokenList *tokenlist) { 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::toLongNumber(tok->astOperand1()->str()); else if (MathLib::isInt(tok->astOperand2()->str())) number = MathLib::toLongNumber(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), tokenlist->getSettings()); setTokenValue(tok, ValueFlow::Value(number), tokenlist->getSettings()); } } } static void valueFlowSameExpressions(TokenList *tokenlist) { 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(), tokenlist->getSettings()->library, true, true, &val.errorPath)) { setTokenValue(tok, val, tokenlist->getSettings()); } } } 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]; bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]); 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; 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->int_bit; else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONG) lhsbits = settings->long_bit; else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONGLONG) lhsbits = settings->long_long_bit; else continue; if (rhsvalue >= lhsbits || rhsvalue >= MathLib::bigint_bits || (1ULL << rhsvalue) <= lhsmax) continue; ValueFlow::Value val(0); val.setKnown(); setTokenValue(tok, val, tokenList->getSettings()); } } 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 void valueFlowImpossibleValues(TokenList* tokenList, const Settings* settings) { for (Token* tok = tokenList->front(); tok; tok = tok->next()) { if (tok->hasKnownIntValue()) continue; 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, value, settings); } 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, 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(), 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 = 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; 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; std::map::const_iterator var = vars.find(tok->variable()); if (var == vars.end()) continue; setTokenValue(tok, var->second, settings); } } static Analyzer::Result valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, std::list values, TokenList* const tokenlist, const Settings* settings); static void valueFlowReverse(TokenList* tokenlist, Token* tok, const Token* const varToken, ValueFlow::Value val, ValueFlow::Value val2, ErrorLogger* errorLogger, const Settings* settings); 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 = parent->astParent(); return (parent && parent->str() == "("); } static const std::string& invertAssign(const std::string& assign) { static std::unordered_map lookup = {{"=", "="}, {"+=", "-="}, {"-=", "+="}, {"*=", "/="}, {"/=", "*="}, {"<<=", ">>="}, {">>=", "<<="}, {"^=", "^="}}; static std::string empty; auto it = lookup.find(assign); if (it == lookup.end()) return empty; else return it->second; } static std::string removeAssign(const std::string& assign) { return std::string{assign.begin(), assign.end() - 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&, const U&) {} 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; } 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 &; explicit Iterator(const M::const_iterator &it) : mIt(it) {} reference operator*() const { return mIt->second; } pointer operator->() { 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 for (const ValueFlow::Value &val : values) { if (!val.isNonValue()) continue; if (val.isInconclusive()) continue; if (val.isLifetimeValue() && !val.isLocalLifetimeValue()) continue; if (val.isLifetimeValue() && val.lifetimeKind != ValueFlow::Value::LifetimeKind::Address) continue; if (!Token::Match(val.tokvalue, ".|&|*|%var%")) continue; if (astHasVar(val.tokvalue, tok->varId())) return true; } return false; } 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 (Token::Match(tok, "%cop%")) return bifurcate(tok->astOperand1(), varids, settings, depth) && bifurcate(tok->astOperand2(), varids, settings, depth); if (Token::Match(tok, "%var%")) { 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; ProgramMemoryState pms; ValueFlowAnalyzer() : tokenlist(nullptr), pms() {} explicit ValueFlowAnalyzer(const TokenList* t) : tokenlist(t), pms() {} 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 isAlias(const Token* tok, bool& inconclusive) const = 0; using ProgramState = std::unordered_map; virtual ProgramState getProgramState() const = 0; virtual const ValueType* getValueType(const Token*) const { return nullptr; } 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 invalid() const { return false; } bool isCPP() const { return tokenlist->isCPP(); } const Settings* getSettings() const { return tokenlist->getSettings(); } 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; } else if (tok->hasKnownIntValue() || tok->isLiteral()) { result.dependent = false; result.unknown = false; return result; } else 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; } else 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.begin(), args.end(), [&](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; } else { 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 { Action read = Action::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; const ValueFlow::Value* value = getValue(tok); // 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 = evaluate(Evaluate::Integral, tok->astParent()->astOperand2()); if (!result.empty() && value->equalTo(result.front())) return Action::Idempotent; } return Action::Invalid; } return read; } virtual Action isAliasModified(const Token* tok) const { int indirect = 0; if (tok->valueType()) indirect = tok->valueType()->pointer; if (isVariableChanged(tok, indirect, 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; } static const std::string& getAssign(const Token* tok, Direction d) { if (d == Direction::Forward) return tok->str(); else 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())) return Action::None; const Token* parent = tok->astParent(); if (parent && parent->isAssignmentOp() && astIsLHS(tok) && parent->astOperand2()->hasKnownValue()) { const Token* rhs = parent->astOperand2(); const ValueFlow::Value* rhsValue = rhs->getKnownValue(ValueFlow::Value::ValueType::INT); Action a; if (!rhsValue || !evalAssignment(*value, getAssign(parent, d), *rhsValue)) a = Action::Invalid; else a = Action::Write; if (parent->str() != "=") { a |= Action::Read; } else { if (rhsValue && !value->isImpossible() && value->equalValue(*rhsValue)) a = Action::Idempotent; 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; if (tok->astParent()->isAssignmentOp()) { const ValueFlow::Value* rhsValue = tok->astParent()->astOperand2()->getKnownValue(ValueFlow::Value::ValueType::INT); assert(rhsValue); if (evalAssignment(*value, getAssign(tok->astParent(), d), *rhsValue)) { const 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, 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() == "++"; std::string opName(inc ? "incremented" : "decremented"); if (d == Direction::Reverse) inc = !inc; value->intvalue += (inc ? 1 : -1); const std::string info(tok->str() + " is " + opName + "', new value is " + value->infoString()); value->errorPath.emplace_back(tok, info); } } virtual bool useSymbolicValues() const { return true; } bool isSameSymbolicValue(const Token* tok, ErrorPath* errorPath = nullptr) const { if (!useSymbolicValues()) return false; for (const ValueFlow::Value& v : tok->values()) { if (!v.isSymbolicValue()) continue; if (!v.isKnown()) continue; if (v.intvalue != 0) continue; if (match(v.tokvalue)) { if (errorPath) errorPath->insert(errorPath->end(), v.errorPath.begin(), v.errorPath.end()); return true; } } return false; } Action analyzeMatch(const Token* tok, Direction d) const { const Token* parent = tok->astParent(); if (astIsPointer(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("*")) { 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 && match(lifeTok)) { 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; } return Action::None; } else if (isAlias(ref, inconclusive)) { inconclusive |= inconclusiveRef; Action a = isAliasModified(tok); if (inconclusive && a.isModified()) return Action::Inconclusive; else return a; } else if (isSameSymbolicValue(ref)) { return Action::Read | Action::SymbolicMatch; } return Action::None; } virtual Action analyze(const Token* tok, Direction d) const OVERRIDE { if (invalid()) return Action::Invalid; // Follow references std::vector refs = followAllReferences(tok); const bool inconclusiveRefs = refs.size() != 1; for (const ReferenceToken& ref:refs) { Action a = analyzeToken(ref.token, tok, d, inconclusiveRefs); if (a != Action::None) return a; } if (dependsOnThis() && exprDependsOnThis(tok)) return isThisModified(tok); // bailout: global non-const variables if (isGlobal() && Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) { 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 { return Action::Invalid; } } return Action::None; } virtual std::vector evaluate(Evaluate e, const Token* tok, const Token* ctx = nullptr) const OVERRIDE { if (e == Evaluate::Integral) { if (tok->hasKnownIntValue()) return {static_cast(tok->values().front().intvalue)}; std::vector result; ProgramMemory pm = pms.get(tok, ctx, getProgramState()); if (Token::Match(tok, "&&|%oror%")) { if (conditionIsTrue(tok, pm)) result.push_back(1); if (conditionIsFalse(tok, pm)) result.push_back(0); } else { MathLib::bigint out = 0; bool error = false; execute(tok, &pm, &out, &error); if (!error) result.push_back(out); } return result; } else 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 {}; } else { return {}; } } virtual 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(); const Token* endBlock = startBlock->link(); pms.removeModifiedVars(endBlock); if (state) 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 = state ? "true" : "false"; addErrorPath(tok, "Assuming condition is " + s); } } if (!(flags & Assume::Absolute)) makeConditional(); } virtual 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, &value->errorPath); } // 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()); } virtual ValuePtr reanalyze(Token*, const std::string&) const OVERRIDE { return {}; } }; ValuePtr makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList* tokenlist); struct SingleValueFlowAnalyzer : ValueFlowAnalyzer { std::unordered_map varids; std::unordered_map aliases; ValueFlow::Value value; SingleValueFlowAnalyzer() : ValueFlowAnalyzer() {} SingleValueFlowAnalyzer(const ValueFlow::Value& v, const TokenList* t) : ValueFlowAnalyzer(t), value(v) {} const std::unordered_map& getVars() const { return varids; } const std::unordered_map& getAliasedVars() const { return aliases; } virtual const ValueFlow::Value* getValue(const Token*) const OVERRIDE { return &value; } virtual ValueFlow::Value* getValue(const Token*) OVERRIDE { return &value; } virtual void makeConditional() OVERRIDE { value.conditional = true; } virtual bool useSymbolicValues() const OVERRIDE { if (value.isUninitValue()) return false; return true; } virtual void addErrorPath(const Token* tok, const std::string& s) OVERRIDE { value.errorPath.emplace_back(tok, s); } virtual 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 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; } virtual bool isGlobal() const OVERRIDE { for (const auto&p:getVars()) { const Variable* var = p.second; if (!var->isLocal() && !var->isArgument() && !var->isConst()) return true; } return false; } virtual bool lowerToPossible() OVERRIDE { if (value.isImpossible()) return false; value.changeKnownToPossible(); return true; } virtual bool lowerToInconclusive() OVERRIDE { if (value.isImpossible()) return false; value.setInconclusive(); return true; } virtual bool isConditional() const OVERRIDE { if (value.conditional) return true; if (value.condition) return !value.isKnown() && !value.isImpossible(); return false; } virtual 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; ConditionState cs = analyzeCondition(condTok); return cs.isUnknownDependent(); } virtual bool updateScope(const Token* endBlock, bool) const OVERRIDE { const Scope* scope = endBlock->scope(); if (!scope) return false; if (scope->type == Scope::eLambda) { return value.isLifetimeValue(); } else 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().begin(), getVars().end(), std::inserter(varids2, varids2.begin()), SelectMapKeys{}); return bifurcate(condTok, varids2, getSettings()); } return false; } virtual ValuePtr reanalyze(Token* tok, const std::string& msg) const OVERRIDE { ValueFlow::Value newValue = value; newValue.errorPath.emplace_back(tok, msg); return makeAnalyzer(tok, newValue, tokenlist); } }; struct ExpressionAnalyzer : SingleValueFlowAnalyzer { const Token* expr; bool local; bool unknown; bool dependOnThis; ExpressionAnalyzer() : SingleValueFlowAnalyzer(), expr(nullptr), local(true), unknown(false), dependOnThis(false) {} ExpressionAnalyzer(const Token* e, const ValueFlow::Value& val, const TokenList* t) : SingleValueFlowAnalyzer(val, t), expr(e), local(true), unknown(false), dependOnThis(false) { assert(e && e->exprId() != 0 && "Not a valid expression"); dependOnThis = exprDependsOnThis(expr); setupExprVarIds(expr); if (val.isSymbolicValue()) setupExprVarIds(val.tokvalue); } virtual const ValueType* getValueType(const Token*) const OVERRIDE { return expr->valueType(); } 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) { for (const ValueFlow::Value& v : tok->values()) { if (!(v.isLocalLifetimeValue() || (astIsPointer(tok) && v.isSymbolicValue() && v.isKnown()))) continue; if (!v.tokvalue) continue; if (v.tokvalue == tok) continue; setupExprVarIds(v.tokvalue, depth + 1); } if (depth == 0 && tok->varId() == 0 && !tok->function() && tok->isName() && tok->previous()->str() != ".") { // unknown 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 invalid() const OVERRIDE { return unknown; } virtual ProgramState getProgramState() const OVERRIDE { ProgramState ps; ps[expr->exprId()] = value; return ps; } virtual bool match(const Token* tok) const OVERRIDE { return tok->exprId() == expr->exprId(); } virtual bool dependsOnThis() const OVERRIDE { return dependOnThis; } virtual bool isGlobal() const OVERRIDE { return !local; } }; struct OppositeExpressionAnalyzer : ExpressionAnalyzer { bool isNot; OppositeExpressionAnalyzer() : ExpressionAnalyzer(), isNot(false) {} OppositeExpressionAnalyzer(bool pIsNot, const Token* e, const ValueFlow::Value& val, const TokenList* t) : ExpressionAnalyzer(e, val, t), isNot(pIsNot) {} virtual bool match(const Token* tok) const OVERRIDE { return isOppositeCond(isNot, isCPP(), expr, tok, getSettings()->library, true, true); } }; static Analyzer::Result valueFlowForwardExpression(Token* startToken, const Token* endToken, const Token* exprTok, const std::list& values, const TokenList* const tokenlist, const Settings* settings) { Analyzer::Result result{}; for (const ValueFlow::Value& v : values) { ExpressionAnalyzer a(exprTok, v, tokenlist); result.update(valueFlowGenericForward(startToken, endToken, a, settings)); } return result; } static const Token* parseBinaryIntOp(const Token* expr, MathLib::bigint& known) { if (!expr) return nullptr; if (!expr->astOperand1() || !expr->astOperand2()) return nullptr; if (expr->astOperand1()->exprId() == 0 && !expr->astOperand1()->hasKnownIntValue()) return nullptr; if (expr->astOperand2()->exprId() == 0 && !expr->astOperand2()->hasKnownIntValue()) return nullptr; const Token* knownTok = nullptr; const Token* varTok = nullptr; if (expr->astOperand1()->hasKnownIntValue() && !expr->astOperand2()->hasKnownIntValue()) { varTok = expr->astOperand2(); knownTok = expr->astOperand1(); } else if (expr->astOperand2()->hasKnownIntValue() && !expr->astOperand1()->hasKnownIntValue()) { varTok = expr->astOperand1(); knownTok = expr->astOperand2(); } if (knownTok) known = knownTok->values().front().intvalue; return varTok; } static const Token* solveExprValue(const Token* expr, 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, intval); if (binaryTok && expr->str().size() == 1) { switch (expr->str()[0]) { case '+': { value.intvalue -= intval; return solveExprValue(binaryTok, value); } case '-': { value.intvalue += intval; return solveExprValue(binaryTok, value); } case '*': { if (intval == 0) break; value.intvalue /= intval; return solveExprValue(binaryTok, value); } case '^': { value.intvalue ^= intval; return solveExprValue(binaryTok, value); } } } return expr; } ValuePtr makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList* tokenlist) { const Token* expr = solveExprValue(exprTok, value); return ExpressionAnalyzer(expr, value, tokenlist); } static Analyzer::Result valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, std::list values, TokenList* const tokenlist, const Settings* settings) { Analyzer::Result result{}; for (const ValueFlow::Value& v : values) { result.update(valueFlowGenericForward(startToken, endToken, makeAnalyzer(exprTok, v, tokenlist), settings)); } return result; } static Analyzer::Result valueFlowForward(Token* top, const Token* exprTok, const std::list& values, TokenList* const tokenlist, const Settings* settings) { Analyzer::Result result{}; for (const ValueFlow::Value& v : values) { result.update(valueFlowGenericForward(top, makeAnalyzer(exprTok, v, tokenlist), settings)); } return result; } static void valueFlowReverse(Token* tok, const Token* const endToken, const Token* const varToken, const std::list& values, TokenList* tokenlist, const Settings* settings) { for (const ValueFlow::Value& v : values) { ExpressionAnalyzer a(varToken, v, tokenlist); valueFlowGenericReverse(tok, endToken, a, settings); } } static void valueFlowReverse(TokenList* tokenlist, Token* tok, const Token* const varToken, ValueFlow::Value val, ValueFlow::Value val2, ErrorLogger* /*errorLogger*/, const Settings* settings) { std::list values = {val}; if (val2.varId != 0) values.push_back(val2); valueFlowReverse(tok, nullptr, varToken, values, tokenlist, settings); } static bool isUniqueSmartPointer(const Token* tok) { if (!astIsSmartPointer(tok)) return false; if (!tok->valueType()->smartPointer) return false; return tok->valueType()->smartPointer->unique; } 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 result = "object"; break; } return result; } std::string 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; std::string type = lifetimeType(tok, val); std::string msg = type; if (vartok) { errorPath.emplace_back(vartok, "Variable created here."); const Variable * var = vartok->variable(); if (var) { switch (val->lifetimeKind) { case ValueFlow::Value::LifetimeKind::SubObject: case ValueFlow::Value::LifetimeKind::Object: case ValueFlow::Value::LifetimeKind::Address: if (type == "pointer") msg += " to local variable"; else msg += " that points to local variable"; break; case ValueFlow::Value::LifetimeKind::Lambda: msg += " that captures local variable"; break; case ValueFlow::Value::LifetimeKind::Iterator: msg += " to local container"; break; } msg += " '" + var->name() + "'"; } } return msg; } std::vector getLifetimeObjValues(const Token *tok, bool inconclusive, bool subfunction) { std::vector result; auto pred = [&](const ValueFlow::Value &v) { if (!v.isLocalLifetimeValue() && !(subfunction && v.isSubFunctionLifetimeValue())) return false; if (!inconclusive && v.isInconclusive()) return false; if (!v.tokvalue->variable()) return false; return true; }; std::copy_if(tok->values().begin(), tok->values().end(), std::back_inserter(result), pred); return result; } ValueFlow::Value getLifetimeObjValue(const Token *tok, bool inconclusive) { std::vector values = getLifetimeObjValues(tok, inconclusive, false); // 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 {}; 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()) { if (!var->declEndToken()) return {{tok, true, std::move(errorPath)}}; if (var->isArgument()) { errorPath.emplace_back(var->declEndToken(), "Passed to reference."); return {{tok, true, std::move(errorPath)}}; } else if (Token::simpleMatch(var->declEndToken(), "=")) { errorPath.emplace_back(var->declEndToken(), "Assigned to reference."); const Token *vartok = var->declEndToken()->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 (contok) return getLifetimeTokens(contok, escape, std::move(errorPath), pred, depth - 1); } 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 (LifetimeToken& lt : getLifetimeTokens(returnTok, escape, errorPath, pred, depth - returns.size())) { const Token* argvarTok = lt.token; const Variable* argvar = argvarTok->variable(); if (!argvar) continue; if (argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) { 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 {}; const Token* argTok = args[n]; lt.errorPath.emplace_back(returnTok, "Return reference."); lt.errorPath.emplace_back(tok->previous(), "Called function passing '" + argTok->expressionString() + "'."); std::vector arglts = LifetimeToken::setInconclusive( getLifetimeTokens(argTok, escape, std::move(lt.errorPath), pred, depth - returns.size()), returns.size() > 1); result.insert(result.end(), arglts.begin(), arglts.end()); } } } return result; } else 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()); 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 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; if (tok->isUnaryOp("*")) vartok = tok->astOperand1(); while (vartok) { if (vartok->str() == "[" || vartok->originalName() == "->") vartok = vartok->astOperand1(); else if (vartok->str() == "." || vartok->str() == "::") vartok = vartok->astOperand2(); else break; } if (!vartok) return {{tok, std::move(errorPath)}}; const Variable *tokvar = vartok->variable(); const bool isContainer = astIsContainer(vartok) && !astIsPointer(vartok); if (!isUniqueSmartPointer(vartok) && !isContainer && !(tokvar && tokvar->isArray() && !tokvar->isArgument()) && (Token::Match(vartok->astParent(), "[|*") || vartok->astParent()->originalName() == "->")) { for (const ValueFlow::Value &v : vartok->values()) { if (!v.isLocalLifetimeValue()) continue; if (v.tokvalue == tok) continue; errorPath.insert(errorPath.end(), v.errorPath.begin(), v.errorPath.end()); return getLifetimeTokens(v.tokvalue, escape, std::move(errorPath), pred, depth - 1); } } else { return LifetimeToken::setAddressOf(getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1), !(astIsContainer(vartok) && Token::simpleMatch(vartok->astParent(), "["))); } } return {{tok, std::move(errorPath)}}; } std::vector getLifetimeTokens(const Token* tok, bool escape, ValueFlow::Value::ErrorPath errorPath) { return getLifetimeTokens(tok, escape, std::move(errorPath), [](const Token*) { return false; }); } bool 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 = 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.begin(), lts.front().errorPath.end()); return lts.front().token; } const Variable* 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* 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 *vt, const ValueType *vtParent) { if (!vtParent) return false; if (!vt) { if (vtParent->type == ValueType::CONTAINER) return true; 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 (vtParent->type == ValueType::CONTAINER) 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 (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; if (vtParent->pointer == vt->pointer && vtParent->type == vt->type && vtParent->isIntegral()) // sign conversion 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 isLifetimeBorrowed(const Token *tok, const Settings *settings) { if (!tok) return true; if (tok->str() == ",") return true; if (!tok->astParent()) return true; if (!Token::Match(tok->astParent()->previous(), "%name% (") && !Token::simpleMatch(tok->astParent(), ",")) { if (!Token::simpleMatch(tok, "{")) { const ValueType *vt = tok->valueType(); const ValueType *vtParent = tok->astParent()->valueType(); if (isLifetimeBorrowed(vt, vtParent)) return true; if (isLifetimeOwned(vt, vtParent)) return false; } if (Token::Match(tok->astParent(), "return|(|{|%assign%")) { if (isDifferentType(tok, tok->astParent())) return false; } } else if (Token::Match(tok->astParent()->tokAt(-3), "%var% . push_back|push_front|insert|push (") && astIsContainer(tok->astParent()->tokAt(-3))) { const ValueType *vt = tok->valueType(); const ValueType *vtCont = tok->astParent()->tokAt(-3)->valueType(); if (!vtCont->containerTypeToken) return true; ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings); if (isLifetimeBorrowed(vt, &vtParent)) return true; if (isLifetimeOwned(vt, &vtParent)) 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 const Token* getEndOfVarScope(const Token* tok, const std::vector& vars) { const Token* endOfVarScope = nullptr; for (const Variable* var : vars) { if (var && (var->isLocal() || var->isArgument())) endOfVarScope = var->typeStartToken()->scope()->bodyEnd; else if (!endOfVarScope) endOfVarScope = tok->scope()->bodyEnd; } return endOfVarScope; } static void valueFlowForwardLifetime(Token * tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) { // Forward lifetimes to constructed variable if (Token::Match(tok->previous(), "%var% {")) { std::list values = tok->values(); values.remove_if(&isNotLifetimeValue); valueFlowForward(nextAfterAstRightmostLeaf(tok), getEndOfVarScope(tok, {tok->variable()}), tok->previous(), values, tokenlist, settings); return; } Token *parent = tok->astParent(); while (parent && (parent->isArithmeticalOp() || 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 (!isLifetimeBorrowed(parent->astOperand2(), settings)) return; std::vector vars = getLHSVariables(parent); const Token* endOfVarScope = getEndOfVarScope(tok, vars); // Only forward lifetime values std::list values = parent->astOperand2()->values(); values.remove_if(&isNotLifetimeValue); // Skip RHS const Token *nextExpression = nextAfterAstRightmostLeaf(parent); if (Token::Match(parent->astOperand1(), ".|[|(")) { valueFlowForwardExpression( const_cast(nextExpression), endOfVarScope, parent->astOperand1(), values, tokenlist, settings); for (ValueFlow::Value& val : values) { if (val.lifetimeKind == ValueFlow::Value::LifetimeKind::Address) val.lifetimeKind = ValueFlow::Value::LifetimeKind::SubObject; } } for (const Variable* var : vars) { valueFlowForward( const_cast(nextExpression), endOfVarScope, var->nameToken(), values, tokenlist, settings); if (tok->astTop() && Token::simpleMatch(tok->astTop()->previous(), "for (") && Token::simpleMatch(tok->astTop()->link(), ") {")) { Token* start = tok->astTop()->link()->next(); valueFlowForward(start, start->link(), var->nameToken(), 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()) { const Variable *var = tok->variable(); const Token *endOfVarScope = var->scope()->bodyEnd; std::list values = tok->values(); const Token *nextExpression = nextAfterAstRightmostLeaf(parent); // Only forward lifetime values values.remove_if(&isNotLifetimeValue); valueFlowForward(const_cast(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 (const ValueFlow::Value& value:values) setTokenValue(parent, value, tokenlist->getSettings()); valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings); } } struct LifetimeStore { const Token *argtok; std::string message; ValueFlow::Value::LifetimeKind type; ErrorPath errorPath; bool inconclusive; bool forward; struct Context { Token* tok; TokenList* tokenlist; ErrorLogger* errorLogger; const Settings* settings; }; LifetimeStore() : argtok(nullptr), message(), type(), errorPath(), inconclusive(false), forward(true), mContext(nullptr) {} LifetimeStore(const Token* argtok, const std::string& message, ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object, bool inconclusive = false) : argtok(argtok), message(message), type(type), errorPath(), inconclusive(inconclusive), forward(true), mContext(nullptr) {} 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, Token *tok, const Variable *var, TokenList *tokenlist, ErrorLogger *errorLogger) { if (!var) return LifetimeStore{}; if (!var->isArgument()) return LifetimeStore{}; int n = getArgumentPos(var, f); if (n < 0) return LifetimeStore{}; std::vector args = getArguments(tok); if (n >= args.size()) { if (tokenlist->getSettings()->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) const { if (!argtok) return false; bool update = false; for (const LifetimeToken& lt : getLifetimeTokens(argtok)) { if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive) continue; ErrorPath er = errorPath; er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end()); 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().begin(), tok->values().end(), value) != tok->values().end()) return false; setTokenValue(tok, value, tokenlist->getSettings()); update = true; } if (update && forward) forwardLifetime(tok, tokenlist, errorLogger, settings); return update; } bool byRef(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings) const { return byRef(tok, tokenlist, errorLogger, settings, [](const Token*) { return true; }); } template bool byVal(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings, Predicate pred) const { if (!argtok) return false; bool update = false; if (argtok->values().empty()) { ErrorPath er; er.emplace_back(argtok, message); const Variable *var = getLifetimeVariable(argtok, er); if (var && var->isArgument()) { ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = ValueFlow::Value::LifetimeScope::Argument; value.tokvalue = var->nameToken(); value.errorPath = er; value.lifetimeKind = type; value.setInconclusive(inconclusive); // Don't add the value a second time if (std::find(tok->values().begin(), tok->values().end(), value) != tok->values().end()) return false; setTokenValue(tok, value, tokenlist->getSettings()); update = true; } } for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok3 = v.tokvalue; for (const LifetimeToken& lt : getLifetimeTokens(tok3)) { if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive) continue; ErrorPath er = v.errorPath; er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end()); if (!lt.token) return false; if (!pred(lt.token)) return false; er.emplace_back(argtok, message); er.insert(er.end(), errorPath.begin(), errorPath.end()); ValueFlow::Value value; value.valueType = ValueFlow::Value::ValueType::LIFETIME; value.lifetimeScope = v.lifetimeScope; value.path = v.path; value.tokvalue = lt.token; 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().begin(), tok->values().end(), value) != tok->values().end()) continue; setTokenValue(tok, value, tokenlist->getSettings()); update = true; } } if (update && forward) forwardLifetime(tok, tokenlist, errorLogger, settings); return update; } bool byVal(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings) const { return byVal(tok, tokenlist, errorLogger, settings, [](const Token*) { return true; }); } template void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const { if (!settings->certainty.isEnabled(Certainty::inconclusive) && inconclusive) return; if (!argtok) return; for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok2 = v.tokvalue; ErrorPath er = v.errorPath; const Variable *var = getLifetimeVariable(tok2, er); er.insert(er.end(), errorPath.begin(), errorPath.end()); if (!var) continue; for (const Token *tok3 = tok; tok3 && tok3 != var->declEndToken(); tok3 = tok3->previous()) { if (tok3->varId() == var->declarationId()) { LifetimeStore{tok3, message, type, inconclusive}.byVal(tok, tokenlist, errorLogger, settings, pred); break; } } } } void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const { byDerefCopy(tok, tokenlist, errorLogger, settings, [](const Token *) { return true; }); } 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 void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) { if (!Token::Match(tok, "%name% (")) return; 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]; // Check if lifetime is available to avoid adding the lifetime twice ValueFlow::Value val = getLifetimeObjValue(argTok); if (val.tokvalue) { LifetimeStore{argTok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Iterator}.byVal( tok->next(), 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 (Token::Match(tok->tokAt(-2), "%var% . push_back|push_front|insert|push|assign") && astIsContainer(tok->tokAt(-2))) { Token *vartok = tok->tokAt(-2); std::vector args = getArguments(tok); 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 '" + vartok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}.byDerefCopy( vartok, tokenlist, errorLogger, settings); } else if (!args.empty() && isLifetimeBorrowed(args.back(), settings)) { LifetimeStore{args.back(), "Added to container '" + vartok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}.byVal( vartok, tokenlist, errorLogger, settings); } } else if (tok->function()) { const Function *f = tok->function(); 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 = getLifetimeVariable(returnTok); if (returnVar && returnVar->isArgument() && (returnVar->isConst() || !isVariableChanged(returnVar, settings, tokenlist->isCPP()))) { LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, returnVar, tokenlist, 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; const Variable *var = v.tokvalue->variable(); LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, var, tokenlist, 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); } } static void valueFlowLifetimeConstructor(Token* tok, const Type* t, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings) { if (!Token::Match(tok, "(|{")) return; if (!t) { if (tok->valueType() && tok->valueType()->type != ValueType::RECORD) 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; // Only support aggregate constructors for now if (scope->numConstructors == 0 && t->derivedFrom.empty() && (t->isClassType() || t->isStructType())) { std::vector args = getArguments(tok); auto it = scope->varlist.begin(); LifetimeStore::forEach(args, "Passed to constructor of '" + t->name() + "'.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { if (it == scope->varlist.end()) return; const Variable& var = *it; if (var.isReference() || var.isRValueReference()) { ls.byRef(tok, tokenlist, errorLogger, settings); } else { ls.byVal(tok, tokenlist, errorLogger, settings); } it++; }); } } static bool hasInitList(const Token* tok) { if (astIsPointer(tok)) return true; if (astIsContainer(tok)) { const Library::Container * library = getLibraryContainer(tok); if (!library) return false; return library->hasInitializerListConstructor; } return false; } static void valueFlowLifetimeConstructor(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings) { if (!Token::Match(tok, "(|{")) return; Token* parent = tok->astParent(); while (Token::simpleMatch(parent, ",")) parent = parent->astParent(); if (Token::simpleMatch(parent, "{") && hasInitList(parent->astParent())) { valueFlowLifetimeConstructor(tok, Token::typeOf(parent->previous()), tokenlist, errorLogger, settings); } else if (Token::simpleMatch(tok, "{") && hasInitList(parent)) { std::vector args = getArguments(tok); // Assume range constructor if passed a pair of iterators if (astIsContainer(parent) && 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 { LifetimeStore::forEach(args, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) { ls.byVal(tok, tokenlist, errorLogger, settings); }); } } else { valueFlowLifetimeConstructor(tok, Token::typeOf(tok->previous()), tokenlist, errorLogger, settings); } } struct Lambda { enum class Capture { Undefined, ByValue, ByReference }; explicit Lambda(const Token * tok) : capture(nullptr), arguments(nullptr), returnTok(nullptr), bodyTok(nullptr), explicitCaptures(), implicitCapture(Capture::Undefined) { 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 (c->variable()) { explicitCaptures[c->variable()] = std::make_pair(c, Capture::ByValue); } else if (c->isUnaryOp("&") && Token::Match(c->astOperand1(), "%var%")) { explicitCaptures[c->astOperand1()->variable()] = std::make_pair(c->astOperand1(), Capture::ByReference); } else { const std::string& s = c->expressionString(); if (s == "=") implicitCapture = Capture::ByValue; else if (s == "&") implicitCapture = Capture::ByReference; } } } const Token * capture; const Token * arguments; const Token * returnTok; const Token * bodyTok; std::unordered_map> explicitCaptures; Capture implicitCapture; std::vector getCaptures() { 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 void valueFlowLifetime(TokenList *tokenlist, SymbolDatabase*, 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); // Lamdas if (lam.isLambda()) { const Scope * bodyScope = lam.bodyTok->scope(); std::set scopes; // Avoid capturing a variable twice std::set varids; 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, Lambda::Capture c, std::function pred) { if (varids.count(tok->varId()) > 0) return; ErrorPath errorPath; if (c == Lambda::Capture::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 == Lambda::Capture::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); } }; // Handle explicit capture for (const auto& p:lam.explicitCaptures) { const Variable* var = p.first; if (!var) continue; const Token* tok2 = p.second.first; Lambda::Capture c = p.second.second; captureVariable(tok2, c, [](const Token*) { return true; }); varids.insert(var->declarationId()); } for (const Token * tok2 = lam.bodyTok; tok2 != lam.bodyTok->link(); tok2 = tok2->next()) { if (!tok2->variable()) continue; captureVariable(tok2, lam.implicitCapture, isImplicitCapturingVariable); } if (update) valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } // address of else if (tok->isUnaryOp("&")) { for (const LifetimeToken& lt : 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, value, tokenlist->getSettings()); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } // container lifetimes else if (astIsContainer(tok)) { Token * parent = astParentSkipParens(tok); if (!Token::Match(parent, ". %name% (")) continue; bool isContainerOfPointers = true; const Token* containerTypeToken = tok->valueType()->containerTypeToken; if (containerTypeToken) { ValueType vt = ValueType::parseDecl(containerTypeToken, settings); isContainerOfPointers = vt.pointer > 0; } LifetimeStore ls; if (astIsIterator(parent->tokAt(2))) ls = LifetimeStore{tok, "Iterator to container is created here.", ValueFlow::Value::LifetimeKind::Iterator}; else if ((astIsPointer(parent->tokAt(2)) && !isContainerOfPointers) || Token::Match(parent->next(), "data|c_str")) ls = LifetimeStore{tok, "Pointer to container is created here.", ValueFlow::Value::LifetimeKind::Object}; else continue; // Dereferencing if (tok->isUnaryOp("*") || parent->originalName() == "->") ls.byDerefCopy(parent->tokAt(2), tokenlist, errorLogger, settings); else ls.byRef(parent->tokAt(2), tokenlist, errorLogger, settings); } // Check constructors else if (Token::Match(tok, "=|return|%type%|%var% {")) { valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings); } // Check function calls else if (Token::Match(tok, "%name% (")) { valueFlowLifetimeFunction(tok, tokenlist, errorLogger, settings); } // Check variables else if (tok->variable()) { ErrorPath errorPath; const Variable * var = 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, value, tokenlist->getSettings()); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } // Forward any lifetimes else if (std::any_of(tok->values().begin(), tok->values().end(), 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 <")) { const 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() == emptyString; } static const Token * findOpenParentesisOfMove(const Token * moveVarTok) { const Token * tok = moveVarTok; while (tok && tok->str() != "(") tok = tok->previous(); return tok; } static const Token * findEndOfFunctionCallForParameter(const Token * parameterToken) { if (!parameterToken) return nullptr; const Token * parent = parameterToken->astParent(); while (parent && !parent->isOp() && parent->str() != "(") parent = parent->astParent(); if (!parent) return nullptr; return nextAfterAstRightmostLeaf(parent); } static void valueFlowAfterMove(TokenList* tokenlist, 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() == emptyString) { varTok = tok; 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(); std::list values; values.push_back(value); const Variable *var = varTok->variable(); if (!var || (!var->isLocal() && !var->isArgument())) continue; const Token * const endOfVarScope = var->scope()->bodyEnd; setTokenValue(varTok, value, settings); valueFlowForward(varTok->next(), endOfVarScope, varTok, values, 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 Variable *var = varTok->variable(); if (!var) continue; const Token * const endOfVarScope = var->scope()->bodyEnd; 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(); std::list values; values.push_back(value); const Token * openParentesisOfMove = findOpenParentesisOfMove(varTok); const Token * endOfFunctionCall = findEndOfFunctionCallForParameter(openParentesisOfMove); if (endOfFunctionCall) valueFlowForward( const_cast(endOfFunctionCall), endOfVarScope, varTok, values, 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) { ValueFlow::Value v(val); v.setKnown(); 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"); 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.begin(), args.end(), std::back_inserter(conds), [&](const Token* tok2) { if (tok2->exprId() == 0) return false; if (tok2->hasKnownIntValue()) return false; return true; }); } return conds; } // static void valueFlowConditionExpressions(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { for (const Scope * scope : symboldatabase->functionScopes) { if (const Token* incompleteTok = findIncompleteVar(scope->bodyStart, scope->bodyEnd)) { if (incompleteTok->isIncompleteVar()) { if (settings->debugwarnings) bailoutIncompleteVar(tokenlist, errorLogger, incompleteTok, "Skipping function due to incomplete variable " + incompleteTok->str()); break; } } for (const Token* tok = 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, true, 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) { ExpressionAnalyzer a1(condTok2, makeConditionValue(1, condTok2, true), tokenlist); valueFlowGenericForward(startTok, startTok->link(), a1, settings); } OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(0, condTok2, true), tokenlist); 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) { ExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist); valueFlowGenericForward(startTok, startTok->link(), a1, settings); if (is1) { OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist); valueFlowGenericForward(startTok, startTok->link(), a2, settings); } } } // Check if the block terminates early if (isEscapeScope(blockTok, tokenlist)) { for (const Token* condTok2:conds) { ExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist); valueFlowGenericForward(startTok->link()->next(), scope->bodyEnd, a1, settings); if (is1) { OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist); valueFlowGenericForward(startTok->link()->next(), scope->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())) { size_t srcSize = ValueFlow::getSizeOf(*src, settings); 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) { 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 void valueFlowSymbolic(TokenList* tokenlist, SymbolDatabase* symboldatabase) { 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(), tokenlist->getSettings()->library, true, tokenlist->isCPP())) continue; if (tok->astOperand1()->valueType() && tok->astOperand2()->valueType()) { if (isTruncated( tok->astOperand2()->valueType(), tok->astOperand1()->valueType(), tokenlist->getSettings())) continue; } else if (isDifferentType(tok->astOperand2(), tok->astOperand1())) { continue; } Token* start = nextAfterAstRightmostLeaf(tok); const Token* end = scope->bodyEnd; 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, tokenlist->getSettings()); 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, tokenlist->getSettings()); } } } static void valueFlowSymbolicAbs(TokenList* tokenlist, SymbolDatabase* symboldatabase) { for (const Scope* scope : symboldatabase->functionScopes) { for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (!Token::Match(tok, "abs|labs|llabs|fabs|fabsf|fabsl (")) continue; if (tok->hasKnownIntValue()) continue; const Token* arg = tok->next()->astOperand2(); if (!arg) 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(), v, tokenlist->getSettings()); } } } template static const ValueFlow::Value* getCompareValue(const std::list& values, Predicate pred, Compare compare) { const ValueFlow::Value* result = nullptr; for (const ValueFlow::Value& value : values) { if (!pred(value)) continue; if (result) result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) { return compare(x.intvalue, y.intvalue); }); else result = &value; } return result; } struct Interval { std::vector minvalue = {}; std::vector maxvalue = {}; std::vector minRef = {}; std::vector maxRef = {}; void setMinValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr) { minvalue = {x}; if (ref) minRef = {ref}; } void setMaxValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr) { maxvalue = {x}; if (ref) maxRef = {ref}; } bool isLessThan(MathLib::bigint x, std::vector* ref = nullptr) const { if (!this->maxvalue.empty() && this->maxvalue.front() < x) { if (ref) *ref = maxRef; return true; } return false; } bool isGreaterThan(MathLib::bigint x, std::vector* ref = nullptr) const { if (!this->minvalue.empty() && this->minvalue.front() > x) { if (ref) *ref = minRef; return true; } return false; } bool isScalar() const { return minvalue.size() == 1 && minvalue == maxvalue; } bool empty() const { return minvalue.empty() && maxvalue.empty(); } bool isScalarOrEmpty() const { return empty() || isScalar(); } MathLib::bigint getScalar() const { assert(isScalar()); return minvalue.front(); } std::vector getScalarRef() const { assert(isScalar()); if (!minRef.empty()) return minRef; if (!maxRef.empty()) return maxRef; return {}; } static Interval fromInt(MathLib::bigint x, const ValueFlow::Value* ref = nullptr) { Interval result; result.setMinValue(x, ref); result.setMaxValue(x, ref); return result; } template static Interval fromValues(const std::list& values, Predicate predicate) { Interval result; const ValueFlow::Value* minValue = getCompareValue(values, predicate, std::less{}); if (minValue) { if (minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper) result.setMinValue(minValue->intvalue + 1, minValue); if (minValue->isPossible() && minValue->bound == ValueFlow::Value::Bound::Lower) result.setMinValue(minValue->intvalue, minValue); if (minValue->isKnown()) return Interval::fromInt(minValue->intvalue, minValue); } const ValueFlow::Value* maxValue = getCompareValue(values, predicate, std::greater{}); if (maxValue) { if (maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower) result.setMaxValue(maxValue->intvalue - 1, maxValue); if (maxValue->isPossible() && maxValue->bound == ValueFlow::Value::Bound::Upper) result.setMaxValue(maxValue->intvalue, maxValue); assert(!maxValue->isKnown()); } return result; } static Interval fromValues(const std::list& values) { return Interval::fromValues(values, [](const ValueFlow::Value&) { return true; }); } template static std::vector apply(const std::vector& x, const std::vector& y, F f) { if (x.empty()) return {}; if (y.empty()) return {}; return {f(x.front(), y.front())}; } static std::vector merge(std::vector x, const std::vector& y) { x.insert(x.end(), y.begin(), y.end()); return x; } friend Interval operator-(const Interval& lhs, const Interval& rhs) { Interval result; result.minvalue = Interval::apply(lhs.minvalue, rhs.maxvalue, std::minus{}); result.maxvalue = Interval::apply(lhs.maxvalue, rhs.minvalue, std::minus{}); if (!result.minvalue.empty()) result.minRef = merge(lhs.minRef, rhs.maxRef); if (!result.maxvalue.empty()) result.maxRef = merge(lhs.maxRef, rhs.minRef); return result; } static std::vector equal(const Interval& lhs, const Interval& rhs, std::vector* ref = nullptr) { if (!lhs.isScalar()) return {}; if (!rhs.isScalar()) return {}; if (ref) *ref = merge(lhs.minRef, rhs.minRef); return {lhs.minvalue == rhs.minvalue}; } static std::vector compare(const Interval& lhs, const Interval& rhs, std::vector* ref = nullptr) { Interval diff = lhs - rhs; if (diff.isGreaterThan(0, ref)) return {1}; if (diff.isLessThan(0, ref)) return {-1}; std::vector eq = Interval::equal(lhs, rhs, ref); if (!eq.empty() && eq.front() != 0) return {0}; return {}; } }; static void addToErrorPath(ValueFlow::Value& value, const std::vector& refs) { for (const ValueFlow::Value* ref : refs) { value.errorPath.insert(value.errorPath.end(), ref->errorPath.begin(), ref->errorPath.end()); } } static void setValueKind(ValueFlow::Value& value, const std::vector& refs) { bool isPossible = false; bool isInconclusive = false; for (const ValueFlow::Value* ref : refs) { if (ref->isPossible()) isPossible = true; if (ref->isInconclusive()) isInconclusive = true; } if (isInconclusive) value.setInconclusive(); else if (isPossible) value.setPossible(); else value.setKnown(); } struct InferModel { virtual bool match(const ValueFlow::Value& value) const = 0; virtual ValueFlow::Value yield(MathLib::bigint value) const = 0; virtual ~InferModel() {} }; static bool inferNotEqual(const std::list& values, MathLib::bigint x) { return std::any_of(values.begin(), values.end(), [&](const ValueFlow::Value& value) { return value.isImpossible() && value.intvalue == x; }); } static std::vector infer(const ValuePtr& model, const std::string& op, std::list lhsValues, std::list rhsValues) { std::vector result; auto notMatch = [&](const ValueFlow::Value& value) { return !model->match(value); }; lhsValues.remove_if(notMatch); rhsValues.remove_if(notMatch); if (lhsValues.empty() || rhsValues.empty()) return result; Interval lhs = Interval::fromValues(lhsValues); Interval rhs = Interval::fromValues(rhsValues); if (op == "-") { Interval diff = lhs - rhs; if (diff.isScalar()) { std::vector refs = diff.getScalarRef(); ValueFlow::Value value(diff.getScalar()); addToErrorPath(value, refs); setValueKind(value, refs); result.push_back(value); } else { if (!diff.minvalue.empty()) { ValueFlow::Value value(diff.minvalue.front() - 1); value.setImpossible(); value.bound = ValueFlow::Value::Bound::Upper; addToErrorPath(value, diff.minRef); result.push_back(value); } if (!diff.maxvalue.empty()) { ValueFlow::Value value(diff.maxvalue.front() + 1); value.setImpossible(); value.bound = ValueFlow::Value::Bound::Lower; addToErrorPath(value, diff.maxRef); result.push_back(value); } } } else if ((op == "!=" || op == "==") && lhs.isScalarOrEmpty() && rhs.isScalarOrEmpty()) { if (lhs.isScalar() && rhs.isScalar()) { std::vector refs = Interval::merge(lhs.getScalarRef(), rhs.getScalarRef()); ValueFlow::Value value(calculate(op, lhs.getScalar(), rhs.getScalar())); addToErrorPath(value, refs); setValueKind(value, refs); result.push_back(value); } else { std::vector refs; if (lhs.isScalar() && inferNotEqual(rhsValues, lhs.getScalar())) refs = lhs.getScalarRef(); else if (rhs.isScalar() && inferNotEqual(lhsValues, rhs.getScalar())) refs = rhs.getScalarRef(); if (!refs.empty()) { ValueFlow::Value value(op == "!="); addToErrorPath(value, refs); setValueKind(value, refs); result.push_back(value); } } } else { std::vector refs; std::vector r = Interval::compare(lhs, rhs, &refs); if (!r.empty()) { int x = r.front(); ValueFlow::Value value(calculate(op, x, 0)); addToErrorPath(value, refs); setValueKind(value, refs); result.push_back(value); } } return result; } static std::vector infer(const ValuePtr& model, const std::string& op, MathLib::bigint lhs, std::list rhsValues) { return infer(model, op, {model->yield(lhs)}, std::move(rhsValues)); } static std::vector infer(const ValuePtr& model, const std::string& op, std::list lhsValues, MathLib::bigint rhs) { return infer(model, op, std::move(lhsValues), {model->yield(rhs)}); } struct SymbolicInferModel : InferModel { const Token* expr; explicit SymbolicInferModel(const Token* tok) : expr(tok) { assert(expr->exprId() != 0); } virtual bool match(const ValueFlow::Value& value) const OVERRIDE { return value.isSymbolicValue() && value.tokvalue && value.tokvalue->exprId() == expr->exprId(); } virtual 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(TokenList* tokenlist, SymbolDatabase* symboldatabase) { 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 (const ValueFlow::Value& value : values) { setTokenValue(tok, value, tokenlist->getSettings()); } } } } static void valueFlowForwardAssign(Token* const tok, const Token* expr, std::vector vars, std::list values, const bool init, TokenList* const tokenlist, ErrorLogger* const errorLogger, const Settings* const settings) { if (Token::simpleMatch(tok->astParent(), "return")) return; const Token* endOfVarScope = getEndOfVarScope(tok, vars); if (std::any_of(values.begin(), values.end(), 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.begin(), vars.end(), [&](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 "; } const std::string info = "Assignment '" + tok->astParent()->expressionString() + "', assigned value is " + valueKind + value.infoString(); value.errorPath.emplace_back(tok, info); } } if (tokenlist->isCPP() && vars.size() == 1 && Token::Match(vars.front()->typeStartToken(), "bool|_Bool")) { std::list::iterator it; for (it = values.begin(); it != values.end(); ++it) { if (it->isIntValue()) it->intvalue = (it->intvalue != 0); if (it->isTokValue()) it->intvalue = (it->tokvalue != nullptr); } } // Static variable initialisation? if (vars.size() == 1 && vars.front()->isStatic() && init) lowerToPossible(values); // Skip RHS const Token * nextExpression = tok->astParent() ? nextAfterAstRightmostLeaf(tok->astParent()) : tok->next(); for (ValueFlow::Value& value : values) { if (value.isSymbolicValue()) continue; if (value.isTokValue()) continue; value.tokvalue = tok; } valueFlowForward(const_cast(nextExpression), endOfVarScope, expr, values, tokenlist, settings); } static void valueFlowForwardAssign(Token* const tok, const Variable* const var, const std::list& values, const bool, const bool init, TokenList* const 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->isBinaryOp() && 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(), ","); } static void valueFlowAfterAssign(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { for (const Scope * scope : symboldatabase->functionScopes) { std::set aliased; for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { // Alias if (tok->isUnaryOp("&")) { aliased.insert(tok->astOperand1()->exprId()); continue; } // Assignment if ((tok->str() != "=" && !isVariableInit(tok)) || (tok->astParent())) continue; // Lhs should be a variable if (!tok->astOperand1() || !tok->astOperand1()->exprId()) continue; const nonneg int exprid = tok->astOperand1()->exprId(); if (aliased.find(exprid) != aliased.end()) continue; std::vector vars = getLHSVariables(tok); // Rhs values.. if (!tok->astOperand2() || tok->astOperand2()->values().empty()) continue; std::list values = truncateValues( tok->astOperand2()->values(), tok->astOperand1()->valueType(), tok->astOperand2()->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; }); // 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(); valueFlowForwardAssign( tok->astOperand2(), tok->astOperand1(), vars, values, init, tokenlist, errorLogger, settings); } } } 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); } static ValueFlow::Value asImpossible(ValueFlow::Value v) { v.invertRange(); v.setImpossible(); return v; } static void insertImpossible(std::list& values, const std::list& input) { std::transform(input.begin(), input.end(), std::back_inserter(values), &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(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; Condition() : vartok(nullptr), true_values(), false_values(), inverted(false), impossible(true) {} }; virtual Analyzer::Result forward(Token* start, const Token* stop, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const = 0; virtual Analyzer::Result forward(Token* top, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const = 0; virtual void reverse(Token* start, const Token* endToken, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const = 0; virtual std::vector parse(const Token* tok, const Settings* settings) const = 0; void traverseCondition(TokenList* tokenlist, SymbolDatabase* symboldatabase, const std::function& f) const { for (const Scope *scope : symboldatabase->functionScopes) { for (Token *tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (Token::Match(tok, "if|while|for (")) 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, tokenlist->getSettings())) { 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, tokenlist->getSettings()->library, true, tokenlist->isCPP())) continue; f(cond, tok, scope); } } } } void beforeCondition(TokenList* tokenlist, SymbolDatabase* symboldatabase, ErrorLogger* errorLogger, const Settings* settings) const { traverseCondition(tokenlist, symboldatabase, [&](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; const 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.begin(), cond.false_values.end()); // 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() && isExpressionChanged( 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 (isExpressionChanged(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); }); } void afterCondition(TokenList* tokenlist, SymbolDatabase* symboldatabase, ErrorLogger* errorLogger, const Settings* settings) const { traverseCondition(tokenlist, symboldatabase, [&](const Condition& cond, Token* tok, const Scope* scope) { if (Token::simpleMatch(tok->astParent(), "?")) return; const Token* top = tok->astTop(); std::list thenValues; std::list elseValues; if (!Token::Match(tok, "!=|=|(|.") && tok != cond.vartok) { thenValues.insert(thenValues.end(), cond.true_values.begin(), cond.true_values.end()); if (cond.impossible && isConditionKnown(tok, false)) insertImpossible(elseValues, cond.false_values); } if (!Token::Match(tok, "==|!")) { elseValues.insert(elseValues.end(), cond.false_values.begin(), cond.false_values.end()); if (cond.impossible && isConditionKnown(tok, true)) { insertImpossible(thenValues, cond.true_values); if (tok == cond.vartok && astIsBool(tok)) insertNegateKnown(thenValues, cond.true_values); } } if (cond.inverted) std::swap(thenValues, elseValues); if (Token::Match(tok->astParent(), "%oror%|&&")) { Token* parent = tok->astParent(); if (astIsRHS(tok) && astIsLHS(parent) && parent->astParent() && parent->str() == parent->astParent()->str()) parent = parent->astParent(); else if (!astIsLHS(tok)) { 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()); } const std::string& op(parent->str()); std::list values; if (op == "&&") values = thenValues; else if (op == "||") values = elseValues; if (Token::Match(tok, "==|!=") || (tok == cond.vartok && astIsBool(tok))) changePossibleToKnown(values); if (astIsFloat(cond.vartok, false) || (!cond.vartok->valueType() && std::all_of(values.begin(), values.end(), [](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) return; } } } { const Token* tok2 = tok; 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 && Token::Match(top->previous(), "if|while (") && !top->previous()->isExpandedMacro()) { // if astParent is "!" we need to invert codeblock { const Token* tok2 = tok; while (tok2->astParent()) { const Token* parent = tok2->astParent(); while (parent && parent->str() == "&&") parent = parent->astParent(); if (parent && (parent->str() == "!" || Token::simpleMatch(parent, "== false"))) std::swap(thenValues, elseValues); tok2 = parent; } } 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; for (int i = 0; i < 2; i++) { const Token* const startToken = startTokens[i]; if (!startToken) continue; std::list& values = (i == 0 ? thenValues : elseValues); valueFlowSetConditionToKnown(tok, 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; 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; } // 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 (tok->astParent() && Token::simpleMatch(tok->astParent()->previous(), "while (")) 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.begin(), thenValues.end(), std::back_inserter(values), std::mem_fn(&ValueFlow::Value::isPossible)); std::copy_if(elseValues.begin(), elseValues.end(), std::back_inserter(values), std::mem_fn(&ValueFlow::Value::isPossible)); } if (values.empty()) return; if (dead_if || dead_else) { const Token* parent = tok->astParent(); // Skip the not operator while (Token::simpleMatch(parent, "!")) parent = parent->astParent(); bool possible = false; if (Token::Match(parent, "&&|%oror%")) { 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 { valueFlowSetConditionToKnown(tok, values, true); valueFlowSetConditionToKnown(tok, values, false); } } if (values.empty()) return; forward(after, scope->bodyEnd, cond.vartok, values, tokenlist, settings); } } }); } virtual ~ConditionHandler() {} }; static void valueFlowCondition(const ValuePtr& handler, TokenList* tokenlist, SymbolDatabase* symboldatabase, ErrorLogger* errorLogger, const Settings* settings) { handler->beforeCondition(tokenlist, symboldatabase, errorLogger, settings); handler->afterCondition(tokenlist, symboldatabase, errorLogger, settings); } struct SimpleConditionHandler : ConditionHandler { virtual Analyzer::Result forward(Token* start, const Token* stop, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const OVERRIDE { return valueFlowForward(start->next(), stop, exprTok, values, tokenlist, settings); } virtual Analyzer::Result forward(Token* top, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const OVERRIDE { return valueFlowForward(top, exprTok, values, tokenlist, settings); } virtual void reverse(Token* start, const Token* endToken, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const OVERRIDE { return valueFlowReverse(start, endToken, exprTok, values, tokenlist, settings); } virtual std::vector parse(const Token* tok, const Settings*) const OVERRIDE { Condition cond; ValueFlow::Value true_value; ValueFlow::Value false_value; const Token *vartok = parseCompareInt(tok, true_value, false_value); if (vartok) { if (vartok->hasKnownIntValue()) return {}; if (vartok->str() == "=" && vartok->astOperand1() && vartok->astOperand2()) vartok = vartok->astOperand1(); cond.true_values.push_back(true_value); cond.false_values.push_back(false_value); cond.vartok = vartok; return {cond}; } 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 {}; cond.true_values.emplace_back(tok, 0LL); cond.false_values.emplace_back(tok, 0LL); cond.vartok = vartok; return {cond}; } }; static bool isInBounds(const ValueFlow::Value& value, MathLib::bigint x) { if (value.intvalue == x) return true; if (value.bound == ValueFlow::Value::Bound::Lower && value.intvalue > x) return false; if (value.bound == ValueFlow::Value::Bound::Upper && value.intvalue < x) return false; // Checking for equality is not necessary since we already know the value is not equal if (value.bound == ValueFlow::Value::Bound::Point) return false; return true; } static const ValueFlow::Value* getCompareIntValue(const std::list& values, std::function compare) { const ValueFlow::Value* result = nullptr; for (const ValueFlow::Value& value : values) { if (!value.isIntValue()) continue; if (result) result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) { return compare(x.intvalue, y.intvalue); }); else result = &value; } return result; } static const ValueFlow::Value* proveLessThan(const std::list& values, MathLib::bigint x) { const ValueFlow::Value* result = nullptr; const ValueFlow::Value* maxValue = getCompareIntValue(values, std::greater {}); if (maxValue && maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower) { if (maxValue->intvalue <= x) result = maxValue; } return result; } static const ValueFlow::Value* proveGreaterThan(const std::list& values, MathLib::bigint x) { const ValueFlow::Value* result = nullptr; const ValueFlow::Value* minValue = getCompareIntValue(values, std::less {}); if (minValue && minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper) { if (minValue->intvalue >= x) result = minValue; } return result; } static const ValueFlow::Value* proveNotEqual(const std::list& values, MathLib::bigint x) { const ValueFlow::Value* result = nullptr; for (const ValueFlow::Value& value : values) { if (value.valueType != ValueFlow::Value::ValueType::INT) continue; if (result && !isInBounds(value, result->intvalue)) continue; if (value.isImpossible()) { if (value.intvalue == x) return &value; if (!isInBounds(value, x)) continue; result = &value; } else { if (value.intvalue == x) return nullptr; if (!isInBounds(value, x)) continue; result = nullptr; } } return result; } ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, MathLib::bigint val) { if (!varTok) return ValueFlow::Value{}; if (varTok->hasKnownIntValue()) return ValueFlow::Value{}; if (std::none_of(varTok->values().begin(), varTok->values().end(), [](const ValueFlow::Value& v) { return v.isImpossible() && v.valueType == ValueFlow::Value::ValueType::INT; })) { return ValueFlow::Value{}; } const ValueFlow::Value* result = nullptr; bool known = false; if (op == "==" || op == "!=") { result = proveNotEqual(varTok->values(), val); known = op == "!="; } else if (op == "<" || op == ">=") { result = proveLessThan(varTok->values(), val); known = op == "<"; if (!result && !isSaturated(val)) { result = proveGreaterThan(varTok->values(), val - 1); known = op == ">="; } } else if (op == ">" || op == "<=") { result = proveGreaterThan(varTok->values(), val); known = op == ">"; if (!result && !isSaturated(val)) { result = proveLessThan(varTok->values(), val + 1); known = op == "<="; } } if (!result) return ValueFlow::Value{}; ValueFlow::Value value = *result; value.intvalue = known; value.bound = ValueFlow::Value::Bound::Point; value.setKnown(); return value; } ValueFlow::Value inferCondition(std::string op, MathLib::bigint val, const Token* varTok) { // Flip the operator if (op == ">") op = "<"; else if (op == "<") op = ">"; else if (op == ">=") op = "<="; else if (op == "<=") op = ">="; return inferCondition(op, varTok, val); } 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 (tok->variable() && (Token::Match(tok->astParent(), "?|&&|!|%oror%") || Token::Match(tok->astParent()->previous(), "if|while ("))) { const ValueFlow::Value* result = proveNotEqual(tok->values(), 0); if (!result) continue; ValueFlow::Value value = *result; value.intvalue = 1; value.bound = ValueFlow::Value::Bound::Point; value.setKnown(); setTokenValue(tok, value, settings); } else if (tok->isComparisonOp()) { ValueFlow::Value value{}; std::string op = tok->str(); if (tok->astOperand1()->hasKnownIntValue()) { MathLib::bigint val = tok->astOperand1()->values().front().intvalue; const Token* varTok = tok->astOperand2(); value = inferCondition(tok->str(), val, varTok); } else if (tok->astOperand2()->hasKnownIntValue()) { MathLib::bigint val = tok->astOperand2()->values().front().intvalue; const Token* varTok = tok->astOperand1(); value = inferCondition(tok->str(), varTok, val); } if (!value.isKnown()) continue; setTokenValue(tok, value, settings); } } } struct SymbolicConditionHandler : SimpleConditionHandler { virtual std::vector parse(const Token* tok, const 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 {}; std::vector result; for (int i = 0; i < 2; i++) { const bool lhs = i == 0; const Token* vartok = lhs ? tok->astOperand1() : tok->astOperand2(); const Token* valuetok = lhs ? tok->astOperand2() : tok->astOperand1(); if (valuetok->hasKnownSymbolicValue(vartok)) 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 = {true_value}; cond.false_values = {false_value}; cond.vartok = vartok; result.push_back(cond); } 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 nonneg int varid, bool globalvar, const MathLib::bigint value, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) { const Token * const bodyEnd = bodyStart->link(); // Is variable modified inside for loop if (isVariableChanged(bodyStart, bodyEnd, varid, globalvar, settings, tokenlist->isCPP())) return; for (Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) { if (tok2->varId() == 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, value1, settings); } if (Token::Match(tok2, "%oror%|&&")) { const ProgramMemory programMemory(getProgramMemory(tok2->astTop(), varid, ValueFlow::Value(value))); if ((tok2->str() == "&&" && !conditionIsTrue(tok2->astOperand1(), programMemory)) || (tok2->str() == "||" && !conditionIsFalse(tok2->astOperand1(), programMemory))) { // Skip second expression.. const 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); } } } if ((tok2->str() == "&&" && conditionIsFalse(tok2->astOperand1(), getProgramMemory(tok2->astTop(), varid, ValueFlow::Value(value)))) || (tok2->str() == "||" && conditionIsTrue(tok2->astOperand1(), getProgramMemory(tok2->astTop(), varid, ValueFlow::Value(value))))) break; else if (Token::simpleMatch(tok2, ") {") && Token::findmatch(tok2->link(), "%varid%", tok2, varid)) { if (Token::findmatch(tok2, "continue|break|return", tok2->linkAt(1), 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), varid)) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "For loop variable bailout on conditional continue|break|return"); break; } tok2 = tok2->linkAt(2); } } else if (Token::simpleMatch(tok2, ") {")) { 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, 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); std::list values; values.emplace_back(num); values.back().errorPath.emplace_back(fortok,"After for loop, " + var->name() + " has value " + values.back().infoString()); if (blockTok != endToken) { valueFlowForward(blockTok->next(), endToken, vartok, values, tokenlist, settings); } } static void valueFlowForLoop(TokenList *tokenlist, 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(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(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)) { ProgramMemory::Map::const_iterator it; for (it = mem1.values.begin(); it != mem1.values.end(); ++it) { if (!it->second.isIntValue()) continue; valueFlowForLoopSimplify(bodyStart, it->first, false, it->second.intvalue, tokenlist, errorLogger, settings); } for (it = mem2.values.begin(); it != mem2.values.end(); ++it) { if (!it->second.isIntValue()) continue; valueFlowForLoopSimplify(bodyStart, it->first, false, it->second.intvalue, tokenlist, errorLogger, settings); } for (it = memAfter.values.begin(); it != memAfter.values.end(); ++it) { if (!it->second.isIntValue()) continue; valueFlowForLoopSimplifyAfter(tok, it->first, it->second.intvalue, tokenlist, settings); } } } } } struct MultiValueFlowAnalyzer : ValueFlowAnalyzer { std::unordered_map values; std::unordered_map vars; SymbolDatabase* symboldatabase; MultiValueFlowAnalyzer() : ValueFlowAnalyzer(), values(), vars(), symboldatabase(nullptr) {} MultiValueFlowAnalyzer(const std::unordered_map& args, const TokenList* t, SymbolDatabase* s) : ValueFlowAnalyzer(t), values(), vars(), symboldatabase(s) { 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; } virtual 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; } virtual 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; } virtual void makeConditional() OVERRIDE { for (auto&& p:values) { p.second.conditional = true; } } virtual void addErrorPath(const Token* tok, const std::string& s) OVERRIDE { for (auto&& p:values) { p.second.errorPath.emplace_back(tok, "Assuming condition is " + s); } } virtual bool isAlias(const Token* tok, bool& inconclusive) const OVERRIDE { const auto range = SelectValueFromVarIdMapRange(&values); for (const auto& p:getVars()) { nonneg int 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; } virtual bool isGlobal() const OVERRIDE { return false; } virtual bool lowerToPossible() OVERRIDE { for (auto&& p:values) { if (p.second.isImpossible()) return false; p.second.changeKnownToPossible(); } return true; } virtual bool lowerToInconclusive() OVERRIDE { for (auto&& p:values) { if (p.second.isImpossible()) return false; p.second.setInconclusive(); } return true; } virtual bool isConditional() const OVERRIDE { for (auto&& p:values) { if (p.second.conditional) return true; if (p.second.condition) return !p.second.isImpossible(); } return false; } virtual bool stopOnCondition(const Token*) const OVERRIDE { return isConditional(); } virtual bool updateScope(const Token* endBlock, bool) const OVERRIDE { const Scope* scope = endBlock->scope(); if (!scope) return false; if (scope->type == Scope::eLambda) { for (const auto& p:values) { if (!p.second.isLifetimeValue()) return false; } return true; } else 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.begin(), values.end(), 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().begin(), getVars().end(), std::inserter(varids, varids.begin()), SelectMapKeys{}); return bifurcate(condTok, varids, getSettings()); } return false; } virtual bool match(const Token* tok) const OVERRIDE { return values.count(tok->varId()) > 0; } virtual ProgramState getProgramState() const OVERRIDE { ProgramState ps; for (const auto& p:values) ps[p.first] = p.second; return ps; } virtual void forkScope(const Token* endBlock) OVERRIDE { ProgramMemory pm = {getProgramState()}; const Scope* scope = endBlock->scope(); const Token* condTok = getCondTokFromEnd(endBlock); if (scope && condTok) programMemoryParseCondition(pm, condTok, nullptr, getSettings(), scope->type != Scope::eElse); if (condTok && Token::simpleMatch(condTok->astParent(), ";")) { ProgramMemory endMemory; if (valueFlowForLoop2(condTok->astTop()->previous(), nullptr, &endMemory, nullptr)) pm.replace(endMemory); } // ProgramMemory pm = pms.get(endBlock->link()->next(), getProgramState()); for (const auto& p:pm.values) { nonneg int varid = p.first; if (!symboldatabase->isVarId(varid)) continue; ValueFlow::Value value = p.second; if (vars.count(varid) != 0) continue; if (value.isImpossible()) continue; value.setPossible(); values[varid] = value; if (symboldatabase) vars[varid] = symboldatabase->getVariableFromVarId(varid); } } }; static void valueFlowInjectParameter(TokenList* tokenlist, SymbolDatabase* symboldatabase, ErrorLogger* errorLogger, const Settings* settings, const Scope* functionScope, const std::unordered_map>& vars) { 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(); } for (const auto& p:vars) { if (args.size() > 256) { std::string fname = ""; Function* f = functionScope->function; if (f) fname = f->name(); if (settings->debugwarnings) bailout(tokenlist, errorLogger, functionScope->bodyStart, "Too many argument passed to " + fname); break; } 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.second.path == 0) continue; if (q.second.path != value.path) return; } } arg[p.first] = value; new_args.push_back(arg); } std::copy(new_args.begin(), new_args.end(), std::back_inserter(args)); }); } for (const auto& arg:args) { if (arg.empty()) continue; bool skip = false; // Make sure all arguments are the same path MathLib::bigint path = arg.begin()->second.path; for (const auto& p:arg) { if (p.second.path != path) { skip = true; break; } } if (skip) continue; MultiValueFlowAnalyzer a(arg, tokenlist, symboldatabase); valueFlowGenericForward(const_cast(functionScope->bodyStart), functionScope->bodyEnd, a, settings); } } static void valueFlowInjectParameter(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, 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 (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::toLongNumber(tok->next()->str())); values.back().condition = tok; const std::string info("case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here."); values.back().errorPath.emplace_back(tok, info); 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::toLongNumber(tok->next()->str())); values.back().condition = tok; const std::string info2("case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here."); values.back().errorPath.emplace_back(tok, info2); } for (std::list::const_iterator val = values.begin(); val != values.end(); ++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 void setTokenValues(Token *tok, const std::list &values, const Settings *settings) { for (const ValueFlow::Value &value : values) { if (value.isIntValue()) setTokenValue(tok, value, settings); } } static bool evaluate(const Token *expr, const std::vector> &values, std::list *result) { if (!expr) return false; // strlen(arg).. if (expr->str() == "(" && Token::Match(expr->previous(), "strlen ( %name% )")) { const Token *arg = expr->next(); if (arg->str().compare(0,3,"arg") != 0 || arg->str().size() != 4) return false; const char n = arg->str()[3]; if (n < '1' || n - '1' >= values.size()) return false; for (const ValueFlow::Value &argvalue : values[n - '1']) { if (argvalue.isTokValue() && argvalue.tokvalue->tokType() == Token::eString) { ValueFlow::Value res(argvalue); // copy all "inconclusive", "condition", etc attributes // set return value.. res.valueType = ValueFlow::Value::ValueType::INT; res.tokvalue = nullptr; res.intvalue = Token::getStrLength(argvalue.tokvalue); result->emplace_back(std::move(res)); } } return !result->empty(); } // unary operands if (expr->astOperand1() && !expr->astOperand2()) { std::list opvalues; if (!evaluate(expr->astOperand1(), values, &opvalues)) return false; if (expr->str() == "+") { result->swap(opvalues); return true; } if (expr->str() == "-") { for (ValueFlow::Value v: opvalues) { if (v.isIntValue()) { v.intvalue = -v.intvalue; result->emplace_back(std::move(v)); } } return true; } return false; } // binary/ternary operands if (expr->astOperand1() && expr->astOperand2()) { std::list lhsValues, rhsValues; if (!evaluate(expr->astOperand1(), values, &lhsValues)) return false; if (expr->str() != "?" && !evaluate(expr->astOperand2(), values, &rhsValues)) return false; for (const ValueFlow::Value &val1 : lhsValues) { if (!val1.isIntValue()) continue; if (expr->str() == "?") { rhsValues.clear(); const Token *expr2 = val1.intvalue ? expr->astOperand2()->astOperand1() : expr->astOperand2()->astOperand2(); if (!evaluate(expr2, values, &rhsValues)) continue; result->insert(result->end(), rhsValues.begin(), rhsValues.end()); continue; } for (const ValueFlow::Value &val2 : rhsValues) { if (!val2.isIntValue()) continue; if (val1.varId != 0 && val2.varId != 0) { if (val1.varId != val2.varId || val1.varvalue != val2.varvalue) continue; } if (expr->str() == "+") result->emplace_back(ValueFlow::Value(val1.intvalue + val2.intvalue)); else if (expr->str() == "-") result->emplace_back(ValueFlow::Value(val1.intvalue - val2.intvalue)); else if (expr->str() == "*") result->emplace_back(ValueFlow::Value(val1.intvalue * val2.intvalue)); else if (expr->str() == "/" && val2.intvalue != 0) result->emplace_back(ValueFlow::Value(val1.intvalue / val2.intvalue)); else if (expr->str() == "%" && val2.intvalue != 0) result->emplace_back(ValueFlow::Value(val1.intvalue % val2.intvalue)); else if (expr->str() == "&") result->emplace_back(ValueFlow::Value(val1.intvalue & val2.intvalue)); else if (expr->str() == "|") result->emplace_back(ValueFlow::Value(val1.intvalue | val2.intvalue)); else if (expr->str() == "^") result->emplace_back(ValueFlow::Value(val1.intvalue ^ val2.intvalue)); else if (expr->str() == "==") result->emplace_back(ValueFlow::Value(val1.intvalue == val2.intvalue)); else if (expr->str() == "!=") result->emplace_back(ValueFlow::Value(val1.intvalue != val2.intvalue)); else if (expr->str() == "<") result->emplace_back(ValueFlow::Value(val1.intvalue < val2.intvalue)); else if (expr->str() == ">") result->emplace_back(ValueFlow::Value(val1.intvalue > val2.intvalue)); else if (expr->str() == ">=") result->emplace_back(ValueFlow::Value(val1.intvalue >= val2.intvalue)); else if (expr->str() == "<=") result->emplace_back(ValueFlow::Value(val1.intvalue <= val2.intvalue)); else if (expr->str() == "&&") result->emplace_back(ValueFlow::Value(val1.intvalue && val2.intvalue)); else if (expr->str() == "||") result->emplace_back(ValueFlow::Value(val1.intvalue || val2.intvalue)); else if (expr->str() == "<<") result->emplace_back(ValueFlow::Value(val1.intvalue << val2.intvalue)); else if (expr->str() == ">>") result->emplace_back(ValueFlow::Value(val1.intvalue >> val2.intvalue)); else return false; combineValueProperties(val1, val2, &result->back()); } } return !result->empty(); } if (expr->str().compare(0,3,"arg")==0) { *result = values[expr->str()[3] - '1']; return true; } if (expr->isNumber()) { result->emplace_back(ValueFlow::Value(MathLib::toLongNumber(expr->str()))); result->back().setKnown(); return true; } else if (expr->tokType() == Token::eChar) { result->emplace_back(ValueFlow::Value(MathLib::toLongNumber(expr->str()))); result->back().setKnown(); return true; } return false; } 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::vector> argValues; for (const Token *argtok : getArguments(tok->previous())) { argValues.emplace_back(getFunctionArgumentValues(argtok)); if (argValues.back().empty()) return; } if (returnValue.find("arg") != std::string::npos && argValues.empty()) return; TokenList tokenList(settings); { const std::string code = "return " + returnValue + ";"; std::istringstream istr(code); if (!tokenList.createTokens(istr)) return; } // combine operators, set links, etc.. std::stack lpar; for (Token *tok2 = tokenList.front(); tok2; tok2 = tok2->next()) { if (Token::Match(tok2, "[!<>=] =")) { tok2->str(tok2->str() + "="); tok2->deleteNext(); } else if (tok2->str() == "(") lpar.push(tok2); else if (tok2->str() == ")") { if (lpar.empty()) return; Token::createMutualLinks(lpar.top(), tok2); lpar.pop(); } } if (!lpar.empty()) return; // Evaluate expression tokenList.createAst(); std::list results; if (evaluate(tokenList.front()->astOperand1(), argValues, &results)) setTokenValues(tok, results, settings); } static void valueFlowSubFunction(TokenList* tokenlist, SymbolDatabase* symboldatabase, ErrorLogger* errorLogger, const Settings* settings) { int id = 0; for (const Scope* scope : symboldatabase->functionScopes) { const Function* function = scope->function; if (!function) continue; for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) { if (!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; }); // Don't forward container sizes for now since programmemory can't evaluate conditions argvalues.remove_if(std::mem_fn(&ValueFlow::Value::isContainerSizeValue)); // 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 = MathLib::toString(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, symboldatabase, errorLogger, settings, calledFunctionScope, argvars); } } } static void valueFlowFunctionDefaultParameter(TokenList* tokenlist, 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(v); } if (!argvalues.empty()) valueFlowInjectParameter(tokenlist, settings, var, scope, argvalues); } } } } static bool isKnown(const Token * tok) { return tok && tok->hasKnownIntValue(); } static void valueFlowFunctionReturn(TokenList *tokenlist, ErrorLogger *errorLogger) { for (Token *tok = tokenlist->back(); tok; tok = tok->previous()) { if (tok->str() != "(" || !tok->astOperand1() || !tok->astOperand1()->function()) continue; if (tok->hasKnownValue()) continue; // Arguments.. std::vector parvalues; if (tok->astOperand2()) { const Token *partok = tok->astOperand2(); while (partok && partok->str() == "," && isKnown(partok->astOperand2())) partok = partok->astOperand1(); if (!isKnown(partok)) continue; parvalues.push_back(partok->values().front().intvalue); partok = partok->astParent(); while (partok && partok->str() == ",") { parvalues.push_back(partok->astOperand2()->values().front().intvalue); partok = partok->astParent(); } if (partok != tok) continue; } // Get scope and args of function const Function * const function = tok->astOperand1()->function(); const Scope * const functionScope = function->functionScope; if (!functionScope || !Token::simpleMatch(functionScope->bodyStart, "{ return")) { if (functionScope && tokenlist->getSettings()->debugwarnings && Token::findsimplematch(functionScope->bodyStart, "return", functionScope->bodyEnd)) bailout(tokenlist, errorLogger, tok, "function return; nontrivial function body"); continue; } ProgramMemory programMemory; for (std::size_t i = 0; i < parvalues.size(); ++i) { const Variable * const arg = function->getArgumentVar(i); if (!arg || !Token::Match(arg->typeStartToken(), "%type% %name% ,|)")) { if (tokenlist->getSettings()->debugwarnings) bailout(tokenlist, errorLogger, tok, "function return; unhandled argument type"); programMemory.clear(); break; } programMemory.setIntValue(arg->declarationId(), parvalues[i]); } if (programMemory.empty() && !parvalues.empty()) continue; // Determine return value of subfunction.. MathLib::bigint result = 0; bool error = false; execute(functionScope->bodyStart->next()->astOperand1(), &programMemory, &result, &error); if (!error) { ValueFlow::Value v(result); if (function->hasVirtualSpecifier()) v.setPossible(); else v.setKnown(); setTokenValue(tok, v, tokenlist->getSettings()); } } } static void valueFlowUninit(TokenList* tokenlist, SymbolDatabase* /*symbolDatabase*/, const Settings* settings) { for (Token *tok = tokenlist->front(); tok; tok = tok->next()) { if (!Token::Match(tok,"[;{}] %type%")) continue; if (!tok->scope()->isExecutable()) continue; const Token *vardecl = tok->next(); bool stdtype = false; bool pointer = false; while (Token::Match(vardecl, "%name%|::|*") && vardecl->varId() == 0) { stdtype |= vardecl->isStandardType(); pointer |= vardecl->str() == "*"; vardecl = vardecl->next(); } // if (!stdtype && !pointer) // continue; if (!Token::Match(vardecl, "%var% ;")) continue; const Variable *var = vardecl->variable(); if (!var || var->nameToken() != vardecl || var->isInit()) continue; if ((!var->isPointer() && var->type() && var->type()->needInitialization != Type::NeedInitialization::True) || !var->isLocal() || var->isStatic() || var->isExtern() || var->isReference() || var->isThrow()) continue; if (!var->type() && !stdtype && !pointer) continue; ValueFlow::Value uninitValue; uninitValue.setKnown(); uninitValue.valueType = ValueFlow::Value::ValueType::UNINIT; uninitValue.tokvalue = vardecl; std::list values; values.push_back(uninitValue); valueFlowForward(vardecl->next(), vardecl->scope()->bodyEnd, var->nameToken(), values, tokenlist, settings); } } static bool isContainerSize(const Token* tok) { if (!Token::Match(tok, "%var% . %name% (")) return false; if (!astIsContainer(tok)) return false; if (tok->valueType()->container && tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::SIZE) return true; if (Token::Match(tok->tokAt(2), "size|length ( )")) return true; return false; } static bool isContainerEmpty(const Token* tok) { if (!Token::Match(tok, "%var% . %name% (")) return false; if (!astIsContainer(tok)) return false; if (tok->valueType()->container && tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::EMPTY) return true; if (Token::simpleMatch(tok->tokAt(2), "empty ( )")) return true; return false; } static bool isContainerSizeChanged(const Token *tok, int depth=20); static bool isContainerSizeChanged(nonneg int varId, const Token *start, const Token *end, int depth = 20); static bool isContainerSizeChangedByFunction(const Token *tok, int depth = 20) { if (!tok->valueType() || !tok->valueType()->container) return false; // If we are accessing an element then we are not changing the container size if (Token::Match(tok, "%name% . %name% (")) { Library::Container::Yield yield = tok->valueType()->container->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->hasVirtualSpecifier()) { const Variable *arg = fun->getArgumentVar(narg); if (arg) { if (!arg->isReference() && !addressOf) return false; if (!addressOf && 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->declarationId(), scope->bodyStart, scope->bodyEnd, depth - 1); } // Don't know => Safe guess return true; } } bool inconclusive = false; const bool isChanged = isVariableChangedByFunctionCall(tok, 0, nullptr, &inconclusive); return (isChanged || inconclusive); } struct ContainerExpressionAnalyzer : ExpressionAnalyzer { ContainerExpressionAnalyzer() : ExpressionAnalyzer() {} ContainerExpressionAnalyzer(const Token* expr, const ValueFlow::Value& val, const TokenList* t) : ExpressionAnalyzer(expr, val, t) {} virtual bool match(const Token* tok) const OVERRIDE { return tok->exprId() == expr->exprId() || (astIsIterator(tok) && isAliasOf(tok, expr->exprId())); } virtual Action isWritable(const Token* tok, Direction d) const OVERRIDE { if (astIsIterator(tok)) return Action::None; if (d == Direction::Reverse) return Action::None; if (!getValue(tok)) return Action::None; if (!tok->valueType() || !tok->valueType()->container) return Action::None; const Token* parent = tok->astParent(); if (tok->valueType()->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; if (rhs->valueType() && rhs->valueType()->container && rhs->valueType()->container->stdStringLike) { if (std::any_of(rhs->values().begin(), rhs->values().end(), [&](const ValueFlow::Value &rhsval) { return rhsval.isKnown() && rhsval.isContainerSizeValue(); })) return Action::Read | Action::Write | Action::Incremental; } } else if (Token::Match(tok, "%name% . %name% (")) { Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2)); 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; } virtual void writeValue(ValueFlow::Value* val, const Token* tok, Direction d) const OVERRIDE { if (d == Direction::Reverse) return; if (!val) return; if (!tok->astParent()) return; const Token* parent = tok->astParent(); if (!tok->valueType() || !tok->valueType()->container) return; if (tok->valueType()->container->stdStringLike && Token::simpleMatch(parent, "+=") && parent->astOperand2()) { const Token* rhs = parent->astOperand2(); if (rhs->tokType() == Token::eString) val->intvalue += Token::getStrLength(rhs); else if (rhs->valueType() && rhs->valueType()->container && rhs->valueType()->container->stdStringLike) { for (const ValueFlow::Value &rhsval : rhs->values()) { if (rhsval.isKnown() && rhsval.isContainerSizeValue()) { val->intvalue += rhsval.intvalue; } } } } else if (Token::Match(tok, "%name% . %name% (")) { Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2)); if (action == Library::Container::Action::PUSH) val->intvalue++; if (action == Library::Container::Action::POP) val->intvalue--; } } virtual 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) && isContainerSizeChanged(tok)) return Action::Invalid; return read; } }; static Analyzer::Result valueFlowContainerForward(Token* startToken, const Token* endToken, const Token* exprTok, const ValueFlow::Value& value, TokenList* tokenlist) { ContainerExpressionAnalyzer a(exprTok, value, tokenlist); return valueFlowGenericForward(startToken, endToken, a, tokenlist->getSettings()); } static Analyzer::Result valueFlowContainerForwardRecursive(Token* top, const Token* exprTok, const ValueFlow::Value& value, TokenList* tokenlist) { ContainerExpressionAnalyzer a(exprTok, value, tokenlist); return valueFlowGenericForward(top, a, tokenlist->getSettings()); } static Analyzer::Result valueFlowContainerForward(Token* startToken, const Token* exprTok, const ValueFlow::Value& value, TokenList* tokenlist) { const Token* endToken = nullptr; const Function* f = Scope::nestedInFunction(startToken->scope()); if (f && f->functionScope) endToken = f->functionScope->bodyEnd; return valueFlowContainerForward(startToken, endToken, exprTok, value, tokenlist); } static void valueFlowContainerReverse(Token* tok, const Token* const endToken, const Token* const varToken, const std::list& values, TokenList* tokenlist, const Settings* settings) { for (const ValueFlow::Value& value : values) { ContainerExpressionAnalyzer a(varToken, value, tokenlist); valueFlowGenericReverse(tok, endToken, a, settings); } } static bool isContainerSizeChanged(const Token *tok, int depth) { if (!tok) return false; if (!tok->valueType() || !tok->valueType()->container) return true; if (Token::Match(tok, "%name% %assign%|<<")) return true; if (Token::Match(tok, "%var% [") && tok->valueType()->container->stdAssociativeLike) return true; if (Token::Match(tok, "%name% . %name% (")) { Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2)); Library::Container::Yield yield = tok->valueType()->container->getYield(tok->strAt(2)); 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: case Library::Container::Action::CHANGE_INTERNAL: return true; case Library::Container::Action::NO_ACTION: // might be unknown action return yield == Library::Container::Yield::NO_YIELD; case Library::Container::Action::FIND: case Library::Container::Action::CHANGE_CONTENT: break; } } if (isContainerSizeChangedByFunction(tok, depth)) return true; return false; } static bool isContainerSizeChanged(nonneg int varId, const Token *start, const Token *end, int depth) { for (const Token *tok = start; tok != end; tok = tok->next()) { if (tok->varId() != varId) continue; if (isContainerSizeChanged(tok, 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 (tok->variable()) { 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(); 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% ;")) { std::list values; ValueFlow::Value v(0); v.setKnown(); values.push_back(v); valueFlowForwardAssign(tok, var, values, false, true, tokenlist, errorLogger, settings); } } else if (Token::Match(tok, "%var% . reset (") && tok->next()->originalName() != "->") { if (Token::simpleMatch(tok->tokAt(3), "( )")) { std::list values; ValueFlow::Value v(0); v.setKnown(); values.push_back(v); valueFlowForwardAssign(tok->tokAt(3), var, values, false, false, tokenlist, errorLogger, settings); } else { tok->removeValues(std::mem_fn(&ValueFlow::Value::isIntValue)); Token* inTok = tok->tokAt(3)->astOperand2(); if (!inTok) continue; std::list values = inTok->values(); const bool constValue = inTok->isNumber(); valueFlowForwardAssign(inTok, var, values, constValue, false, tokenlist, errorLogger, settings); } } else if (Token::Match(tok, "%var% . release ( )") && tok->next()->originalName() != "->") { std::list values; ValueFlow::Value v(0); v.setKnown(); values.push_back(v); valueFlowForwardAssign(tok->tokAt(3), var, values, false, false, tokenlist, errorLogger, 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 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; if (Token::Match(tok->astParent(), ". %name% (")) { Library::Container::Yield yield = tok->valueType()->container->getYield(tok->astParent()->strAt(1)); ValueFlow::Value v(0); v.setKnown(); if (yield == Library::Container::Yield::START_ITERATOR) { v.valueType = ValueFlow::Value::ValueType::ITERATOR_START; setTokenValue(tok->astParent()->tokAt(2), v, settings); } else if (yield == Library::Container::Yield::END_ITERATOR) { v.valueType = ValueFlow::Value::ValueType::ITERATOR_END; setTokenValue(tok->astParent()->tokAt(2), 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 { virtual std::vector parse(const Token* tok, const Settings*) const OVERRIDE { Condition cond; ValueFlow::Value true_value; ValueFlow::Value false_value; if (Token::Match(tok, "==|!=")) { if (!tok->astOperand1() || !tok->astOperand2()) return {}; 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()); 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 {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.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, v, settings); } } } static std::vector getContainerValues(const Token* tok) { std::vector values; if (tok) { std::copy_if(tok->values().begin(), tok->values().end(), 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 getInitListSize(const Token* tok, const Library::Container* container, bool known = true) { std::vector args = getArguments(tok); // Strings don't use an init list if (!args.empty() && container->stdStringLike) { if (astIsIntegral(args[0], false)) { if (args.size() > 1) return {makeContainerSizeValue(args[0], known)}; } else if (astIsPointer(args[0])) { // TODO: Try to read size of string literal if (args.size() == 2 && astIsIntegral(args[1], false)) return {makeContainerSizeValue(args[1], known)}; } else if (astIsContainer(args[0])) { if (args.size() == 1) return getContainerValues(args[0]); if (args.size() == 3) return {makeContainerSizeValue(args[2], known)}; } return {}; } else if ((args.size() == 1 && astIsContainer(args[0]) && args[0]->valueType()->container == container) || (args.size() == 2 && astIsIterator(args[0]) && astIsIterator(args[1]))) { return getContainerValues(args[0]); } return {makeContainerSizeValue(args.size(), known)}; } static void valueFlowContainerSize(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger * /*errorLogger*/, const Settings *settings) { std::map static_sizes; // declaration for (const Variable *var : symboldatabase->variableList()) { bool known = true; if (!var || !var->isLocal() || var->isPointer() || var->isReference() || var->isStatic()) continue; if (!var->valueType() || !var->valueType()->container) continue; if (!astIsContainer(var->nameToken())) continue; if (var->nameToken()->hasKnownValue(ValueFlow::Value::ValueType::CONTAINER_SIZE)) continue; if (!Token::Match(var->nameToken(), "%name% ;") && !(Token::Match(var->nameToken(), "%name% {") && Token::simpleMatch(var->nameToken()->next()->link(), "} ;"))) continue; if (var->nameToken()->astTop() && Token::Match(var->nameToken()->astTop()->previous(), "for|while")) known = !isVariableChanged(var, settings, true); if (var->valueType()->container->size_templateArgNo >= 0) { if (var->dimensions().size() == 1 && var->dimensions().front().known) static_sizes[var->declarationId()] = var->dimensions().front().num; continue; } std::vector values{ValueFlow::Value{0}}; values.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; if (known) values.back().setKnown(); if (Token::simpleMatch(var->nameToken()->next(), "{")) { const Token* initList = var->nameToken()->next(); values = getInitListSize(initList, var->valueType()->container, known); } for (const ValueFlow::Value& value : values) valueFlowContainerForward(var->nameToken()->next(), var->nameToken(), value, tokenlist); } // after assignment for (const Scope *functionScope : symboldatabase->functionScopes) { for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) { if (static_sizes.count(tok->varId()) > 0) { ValueFlow::Value value(static_sizes.at(tok->varId())); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); setTokenValue(const_cast(tok), value, settings); } else if (Token::Match(tok, "%name%|;|{|} %var% = %str% ;")) { const Token *containerTok = tok->next(); if (containerTok && containerTok->valueType() && containerTok->valueType()->container && containerTok->valueType()->container->stdStringLike) { ValueFlow::Value value(Token::getStrLength(containerTok->tokAt(2))); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowContainerForward(containerTok->next(), containerTok, value, tokenlist); } } else if (Token::Match(tok, "%name%|;|{|}|> %var% = {") && Token::simpleMatch(tok->linkAt(3), "} ;")) { const Token* containerTok = tok->next(); if (astIsContainer(containerTok) && containerTok->valueType()->container->size_templateArgNo < 0) { std::vector values = getInitListSize(tok->tokAt(3), containerTok->valueType()->container); for (const ValueFlow::Value& value : values) valueFlowContainerForward(containerTok->next(), containerTok, value, tokenlist); } } else if (Token::Match(tok, ". %name% (") && tok->astOperand1() && tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->container) { const Token* containerTok = tok->astOperand1(); 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(); valueFlowContainerForward(tok->next(), containerTok, value, tokenlist); } 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(); valueFlowContainerForward(tok->next(), containerTok, value, tokenlist); } } } } } struct ContainerConditionHandler : ConditionHandler { virtual Analyzer::Result forward(Token* start, const Token* stop, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings*) const OVERRIDE { Analyzer::Result result{}; for (const ValueFlow::Value& value : values) result.update(valueFlowContainerForward(start->next(), stop, exprTok, value, tokenlist)); return result; } virtual Analyzer::Result forward(Token* top, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings*) const OVERRIDE { Analyzer::Result result{}; for (const ValueFlow::Value& value : values) result.update(valueFlowContainerForwardRecursive(top, exprTok, value, tokenlist)); return result; } virtual void reverse(Token* start, const Token* endTok, const Token* exprTok, const std::list& values, TokenList* tokenlist, const Settings* settings) const OVERRIDE { return valueFlowContainerReverse(start, endTok, exprTok, values, tokenlist, settings); } virtual std::vector parse(const Token* tok, const Settings*) const OVERRIDE { Condition cond; ValueFlow::Value true_value; ValueFlow::Value false_value; const Token *vartok = parseCompareInt(tok, true_value, false_value); if (vartok) { vartok = vartok->tokAt(-3); if (!isContainerSize(vartok)) return {}; true_value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; false_value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; cond.true_values.push_back(true_value); cond.false_values.push_back(false_value); cond.vartok = vartok; return {cond}; } // Empty check if (tok->str() == "(") { vartok = tok->tokAt(-3); // TODO: Handle .size() if (!isContainerEmpty(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; cond.true_values.emplace_back(value); cond.false_values.emplace_back(std::move(value)); cond.vartok = vartok; cond.inverted = true; return {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; cond.false_values.emplace_back(value); cond.true_values.emplace_back(std::move(value)); cond.vartok = vartok; cond.impossible = false; return {cond}; } return {}; } }; static void valueFlowDynamicBufferSize(TokenList* tokenlist, SymbolDatabase* symboldatabase, const Settings* settings) { 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; if (!Token::Match(rhs->previous(), "%name% (")) continue; const Library::AllocFunc *allocFunc = settings->library.getAllocFuncInfo(rhs->previous()); if (!allocFunc) allocFunc = settings->library.getReallocFuncInfo(rhs->previous()); if (!allocFunc || allocFunc->bufferSize == Library::AllocFunc::BufferSize::none) continue; const std::vector args = getArguments(rhs->previous()); 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; MathLib::bigint sizeValue = -1; 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; } if (sizeValue < 0) continue; ValueFlow::Value value(sizeValue); value.errorPath.emplace_back(tok->tokAt(2), "Assign " + tok->strAt(1) + ", buffer with size " + MathLib::toString(sizeValue)); value.valueType = ValueFlow::Value::ValueType::BUFFER_SIZE; value.setKnown(); const std::list values{value}; valueFlowForward(const_cast(rhs), functionScope->bodyEnd, tok->next(), values, tokenlist, settings); } } } static bool getMinMaxValues(const ValueType *vt, const cppcheck::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, minvalue, maxvalue); } static void valueFlowSafeFunctions(TokenList* tokenlist, 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->platformType != cppcheck::Platform::PlatformType::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) valueFlowContainerForward( const_cast(functionScope->bodyStart), arg.nameToken(), value, tokenlist); 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, &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 : -1E25f; 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 : 1E25f; 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 " + MathLib::toString(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 " + MathLib::toString(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(const_cast(tok), ValueFlow::Value(value), settings); } } } ValueFlow::Value::Value(const Token* c, long long val, Bound b) : valueType(ValueType::INT), bound(b), intvalue(val), tokvalue(nullptr), floatValue(0.0), moveKind(MoveKind::NonMovedVariable), varvalue(val), condition(c), varId(0), safe(false), conditional(false), defaultArg(false), indirect(0), path(0), wideintvalue(0), lifetimeKind(LifetimeKind::Object), lifetimeScope(LifetimeScope::Local), valueKind(ValueKind::Possible) { errorPath.emplace_back(c, "Assuming that condition '" + c->expressionString() + "' is not redundant"); } void ValueFlow::Value::assumeCondition(const Token* tok) { condition = tok; errorPath.emplace_back(tok, "Assuming that condition '" + tok->expressionString() + "' is not redundant"); } std::string ValueFlow::Value::infoString() const { switch (valueType) { case ValueType::INT: return MathLib::toString(intvalue); case ValueType::TOK: return tokvalue->str(); case ValueType::FLOAT: return MathLib::toString(floatValue); case ValueType::MOVED: return ""; case ValueType::UNINIT: return ""; case ValueType::BUFFER_SIZE: case ValueType::CONTAINER_SIZE: return "size=" + MathLib::toString(intvalue); case ValueType::ITERATOR_START: return "start=" + MathLib::toString(intvalue); case ValueType::ITERATOR_END: return "end=" + MathLib::toString(intvalue); case ValueType::LIFETIME: return "lifetime=" + tokvalue->str(); case ValueType::SYMBOLIC: std::string result = "symbolic=" + tokvalue->expressionString(); if (intvalue > 0) result += "+" + MathLib::toString(intvalue); else if (intvalue < 0) result += "-" + MathLib::toString(-intvalue); return result; } throw InternalError(nullptr, "Invalid ValueFlow Value type"); } const char* ValueFlow::Value::toString(MoveKind moveKind) { switch (moveKind) { case MoveKind::NonMovedVariable: return "NonMovedVariable"; case MoveKind::MovedVariable: return "MovedVariable"; case MoveKind::ForwardedVariable: return "ForwardedVariable"; } return ""; } const char* ValueFlow::Value::toString(LifetimeKind lifetimeKind) { switch (lifetimeKind) { case LifetimeKind::Object: return "Object"; case LifetimeKind::SubObject: return "SubObject"; case LifetimeKind::Lambda: return "Lambda"; case LifetimeKind::Iterator: return "Iterator"; case LifetimeKind::Address: return "Address"; } return ""; } bool ValueFlow::Value::sameToken(const Token* tok1, const Token* tok2) { if (tok1 == tok2) return true; if (!tok1) return false; if (tok1->exprId() == 0 || tok2->exprId() == 0) return false; return tok1->exprId() == tok2->exprId(); } const char* ValueFlow::Value::toString(LifetimeScope lifetimeScope) { switch (lifetimeScope) { case ValueFlow::Value::LifetimeScope::Local: return "Local"; case ValueFlow::Value::LifetimeScope::Argument: return "Argument"; case ValueFlow::Value::LifetimeScope::SubFunction: return "SubFunction"; } return ""; } const char* ValueFlow::Value::toString(Bound bound) { switch (bound) { case ValueFlow::Value::Bound::Point: return "Point"; case ValueFlow::Value::Bound::Upper: return "Upper"; case ValueFlow::Value::Bound::Lower: return "Lower"; } return ""; } 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; } static std::size_t getTotalValues(TokenList *tokenlist) { std::size_t n = 1; for (Token *tok = tokenlist->front(); tok; tok = tok->next()) n += tok->values().size(); return n; } void ValueFlow::setValues(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { for (Token *tok = tokenlist->front(); tok; tok = tok->next()) tok->clearValueFlow(); valueFlowEnumValue(symboldatabase, settings); valueFlowNumber(tokenlist); valueFlowString(tokenlist); valueFlowArray(tokenlist); valueFlowUnknownFunctionReturn(tokenlist, settings); valueFlowGlobalConstVar(tokenlist, settings); valueFlowEnumValue(symboldatabase, settings); valueFlowNumber(tokenlist); valueFlowGlobalStaticVar(tokenlist, settings); valueFlowPointerAlias(tokenlist); valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings); valueFlowSymbolic(tokenlist, symboldatabase); valueFlowBitAnd(tokenlist); valueFlowSameExpressions(tokenlist); valueFlowConditionExpressions(tokenlist, symboldatabase, errorLogger, settings); std::size_t values = 0; std::size_t n = 4; while (n > 0 && values < getTotalValues(tokenlist)) { values = getTotalValues(tokenlist); valueFlowImpossibleValues(tokenlist, settings); valueFlowSymbolicAbs(tokenlist, symboldatabase); valueFlowCondition(SymbolicConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings); valueFlowSymbolicInfer(tokenlist, symboldatabase); valueFlowArrayBool(tokenlist); valueFlowRightShift(tokenlist, settings); valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, settings); valueFlowCondition(SimpleConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings); valueFlowInferCondition(tokenlist, settings); valueFlowSwitchVariable(tokenlist, symboldatabase, errorLogger, settings); valueFlowForLoop(tokenlist, symboldatabase, errorLogger, settings); valueFlowSubFunction(tokenlist, symboldatabase, errorLogger, settings); valueFlowFunctionReturn(tokenlist, errorLogger); valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings); valueFlowFunctionDefaultParameter(tokenlist, symboldatabase, settings); valueFlowUninit(tokenlist, symboldatabase, settings); valueFlowUninitPointerAliasDeref(tokenlist); if (tokenlist->isCPP()) { valueFlowAfterMove(tokenlist, symboldatabase, settings); valueFlowSmartPointer(tokenlist, errorLogger, settings); valueFlowIterators(tokenlist, settings); valueFlowCondition(IteratorConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings); valueFlowIteratorInfer(tokenlist, settings); valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings); valueFlowCondition(ContainerConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings); } valueFlowSafeFunctions(tokenlist, symboldatabase, settings); n--; } valueFlowDynamicBufferSize(tokenlist, symboldatabase, settings); } ValueFlow::Value ValueFlow::Value::unknown() { Value v; v.valueType = Value::ValueType::UNINIT; return v; } 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, 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; } 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 (indexValue->bound != ValueFlow::Value::Bound::Lower) return {}; if (size.bound == ValueFlow::Value::Bound::Lower) return {}; ValueFlow::Value inBoundsValue = inferCondition("<", indexTok, size.intvalue); if (inBoundsValue.isKnown() && inBoundsValue.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 {value}; } std::vector ValueFlow::isOutOfBounds(const Value& size, const Token* indexTok, bool possible) { std::vector result = isOutOfBoundsImpl(size, indexTok, false); if (!result.empty()) return result; if (!possible) return result; return isOutOfBoundsImpl(size, indexTok, true); }