/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2020 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 valueFlowForwardVariable 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 "astutils.h" #include "errorlogger.h" #include "forwardanalyzer.h" #include "library.h" #include "mathlib.h" #include "path.h" #include "platform.h" #include "programmemory.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 static void bailoutInternal(TokenList *tokenlist, ErrorLogger *errorLogger, const Token *tok, const std::string &what, const std::string &file, int line, const std::string &function) { std::list callstack(1, ErrorMessage::FileLocation(tok, tokenlist)); ErrorMessage errmsg(callstack, tokenlist->getSourceFilePath(), Severity::debug, Path::stripDirectoryPart(file) + ":" + MathLib::toString(line) + ":" + function + " bailout: " + what, "valueFlowBailout", false); errorLogger->reportErr(errmsg); } #if (defined __cplusplus) && __cplusplus >= 201103L #define bailout(tokenlist, errorLogger, tok, what) bailoutInternal(tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __func__) #elif (defined __GNUC__) || (defined __clang__) || (defined _MSC_VER) #define bailout(tokenlist, errorLogger, tok, what) bailoutInternal(tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __FUNCTION__) #else #define bailout(tokenlist, errorLogger, tok, what) bailoutInternal(tokenlist, errorLogger, tok, what, __FILE__, __LINE__, "(valueFlow)") #endif 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 invert, 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 (invert) 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 (invert) 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, invert); setValueBound(false_value, tok, !invert); } 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) { if (!tok->astOperand1() || !tok->astOperand2()) return nullptr; if (tok->isComparisonOp()) { if (tok->astOperand1()->hasKnownIntValue()) { MathLib::bigint value = tok->astOperand1()->values().front().intvalue; if (isSaturated(value)) return nullptr; setConditionalValues(tok, true, value, true_value, false_value); return tok->astOperand2(); } else if (tok->astOperand2()->hasKnownIntValue()) { MathLib::bigint value = tok->astOperand2()->values().front().intvalue; if (isSaturated(value)) return nullptr; setConditionalValues(tok, false, value, true_value, false_value); return tok->astOperand1(); } } return nullptr; } /** * Should value be skipped because it's hidden inside && || or ?: expression. * Example: ((x!=NULL) && (*x == 123)) * If 'valuetok' points at the x in '(*x == 123)'. Then the '&&' will be returned. * @param valuetok original variable token * @return NULL=>don't skip, non-NULL=>The operator token that cause the skip. For instance the '&&'. * */ static const Token * skipValueInConditionalExpression(const Token * const valuetok) { // Walk up the ast const Token *prev = valuetok; for (const Token *tok = valuetok->astParent(); tok; tok = tok->astParent()) { const bool prevIsLhs = (prev == tok->astOperand1()); prev = tok; if (prevIsLhs || !Token::Match(tok, "%oror%|&&|?|:")) continue; if (tok->hasKnownIntValue()) return tok; // Is variable protected in LHS.. bool bailout = false; visitAstNodes(tok->astOperand1(), [&](const Token *tok2) { if (tok2->str() == ".") return ChildrenToVisit::none; // A variable is seen.. if (tok2 != valuetok && tok2->variable() && (tok2->varId() == valuetok->varId() || (!tok2->variable()->isArgument() && !tok2->hasKnownIntValue()))) { // TODO: limit this bailout bailout = true; return ChildrenToVisit::done; } return ChildrenToVisit::op1_and_op2; }); if (bailout) return tok; } return nullptr; } 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 bool bailoutSelfAssignment(const Token * const tok) { const Token *parent = tok; while (parent) { const Token *op = parent; parent = parent->astParent(); // Assignment where lhs variable exists in rhs => return true if (parent != nullptr && parent->astOperand2() == op && parent->astOperand1() != nullptr && parent->str() == "=") { for (const Token *lhs = parent->astOperand1(); lhs; lhs = lhs->astOperand1()) { if (lhs->varId() == tok->varId()) return true; if (lhs->astOperand2() && lhs->astOperand2()->varId() == tok->varId()) return true; } } } return false; } static ValueFlow::Value castValue(ValueFlow::Value value, const ValueType::Sign sign, nonneg int bit) { if (value.isFloatValue()) { value.valueType = ValueFlow::Value::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 != 0U) ? 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; } /** Set token value for cast */ static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings); /** set ValueFlow value and perform calculations if possible */ static void setTokenValue(Token* tok, const ValueFlow::Value &value, const Settings *settings) { if (!tok->addValue(value)) return; if (value.path < 0) return; Token *parent = tok->astParent(); if (!parent) return; if (value.isContainerSizeValue()) { // .empty, .size, +"abc", +'a' if (parent->str() == "+" && parent->astOperand1() && parent->astOperand2()) { for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) { for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) { if (value1.path != value2.path) continue; ValueFlow::Value result; result.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; if (value1.isContainerSizeValue() && value2.isContainerSizeValue()) result.intvalue = value1.intvalue + value2.intvalue; else if (value1.isContainerSizeValue() && value2.isTokValue() && value2.tokvalue->tokType() == Token::eString) result.intvalue = value1.intvalue + Token::getStrLength(value2.tokvalue); else if (value2.isContainerSizeValue() && value1.isTokValue() && value1.tokvalue->tokType() == Token::eString) result.intvalue = Token::getStrLength(value1.tokvalue) + value2.intvalue; else continue; combineValueProperties(value1, value2, &result); 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->isArithmeticalOp() || Token::Match(parent, "( %type%"))) { 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::INT && Token::simpleMatch(parent->astOperand1(), "dynamic_cast")) return; const ValueType &valueType = ValueType::parseDecl(castType, settings); 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? int varId = 0; bool ret = false; visitAstNodes(parent->astOperand1(), [&](const Token *t) { if (t->varId()) { if (varId > 0 || value.varId != 0U) 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 (value1.isKnown() || value2.isKnown() || value1.varId == 0U || value2.varId == 0U || (value1.varId == value2.varId && value1.varvalue == value2.varvalue && value1.isIntValue() && value2.isIntValue())) { ValueFlow::Value result(0); combineValueProperties(value1, value2, &result); const float floatValue1 = value1.isIntValue() ? value1.intvalue : value1.floatValue; const float floatValue2 = value2.isIntValue() ? value2.intvalue : value2.floatValue; switch (parent->str()[0]) { case '+': if (value1.isTokValue() || value2.isTokValue()) break; if (value1.isFloatValue() || value2.isFloatValue()) { result.valueType = ValueFlow::Value::FLOAT; result.floatValue = floatValue1 + floatValue2; } else { result.intvalue = value1.intvalue + value2.intvalue; } setTokenValue(parent, result, settings); break; case '-': if (value1.isTokValue() || value2.isTokValue()) break; if (value1.isFloatValue() || value2.isFloatValue()) { result.valueType = ValueFlow::Value::FLOAT; result.floatValue = floatValue1 - floatValue2; } else { // Avoid overflow if (value1.intvalue < 0 && value2.intvalue > value1.intvalue - LLONG_MIN) break; result.intvalue = value1.intvalue - value2.intvalue; } // If the bound comes from the second value then invert the bound if (value2.bound == result.bound && value2.bound != ValueFlow::Value::Bound::Point) result.invertBound(); setTokenValue(parent, result, settings); break; case '*': if (value1.isTokValue() || value2.isTokValue()) break; if (value1.isFloatValue() || value2.isFloatValue()) { result.valueType = ValueFlow::Value::FLOAT; result.floatValue = floatValue1 * floatValue2; } else { result.intvalue = value1.intvalue * value2.intvalue; } setTokenValue(parent, result, settings); break; case '/': if (value1.isTokValue() || value2.isTokValue() || value2.intvalue == 0) break; if (value1.isFloatValue() || value2.isFloatValue()) { result.valueType = ValueFlow::Value::FLOAT; result.floatValue = floatValue1 / floatValue2; } else { result.intvalue = value1.intvalue / value2.intvalue; } setTokenValue(parent, result, settings); break; case '%': if (!value1.isIntValue() || !value2.isIntValue()) break; if (value2.intvalue == 0) break; result.intvalue = value1.intvalue % value2.intvalue; setTokenValue(parent, result, settings); break; case '=': if (parent->str() == "==") { if ((value1.isIntValue() && value2.isTokValue()) || (value1.isTokValue() && value2.isIntValue())) { result.intvalue = 0; setTokenValue(parent, result, settings); } else if (value1.isIntValue() && value2.isIntValue()) { result.intvalue = value1.intvalue == value2.intvalue; setTokenValue(parent, result, settings); } } break; case '!': if (parent->str() == "!=") { if ((value1.isIntValue() && value2.isTokValue()) || (value1.isTokValue() && value2.isIntValue())) { result.intvalue = 1; setTokenValue(parent, result, settings); } else if (value1.isIntValue() && value2.isIntValue()) { result.intvalue = value1.intvalue != value2.intvalue; setTokenValue(parent, result, settings); } } break; case '>': { const bool f = value1.isFloatValue() || value2.isFloatValue(); if (!f && !value1.isIntValue() && !value2.isIntValue()) break; if (parent->str() == ">") result.intvalue = f ? (floatValue1 > floatValue2) : (value1.intvalue > value2.intvalue); else if (parent->str() == ">=") result.intvalue = f ? (floatValue1 >= floatValue2) : (value1.intvalue >= value2.intvalue); else if (!f && parent->str() == ">>" && value1.intvalue >= 0 && value2.intvalue >= 0 && value2.intvalue < MathLib::bigint_bits) result.intvalue = value1.intvalue >> value2.intvalue; else break; setTokenValue(parent, result, settings); break; } case '<': { const bool f = value1.isFloatValue() || value2.isFloatValue(); if (!f && !value1.isIntValue() && !value2.isIntValue()) break; if (parent->str() == "<") result.intvalue = f ? (floatValue1 < floatValue2) : (value1.intvalue < value2.intvalue); else if (parent->str() == "<=") result.intvalue = f ? (floatValue1 <= floatValue2) : (value1.intvalue <= value2.intvalue); else if (!f && parent->str() == "<<" && value1.intvalue >= 0 && value2.intvalue >= 0 && value2.intvalue < MathLib::bigint_bits) result.intvalue = value1.intvalue << value2.intvalue; else break; setTokenValue(parent, result, settings); break; } case '&': if (!value1.isIntValue() || !value2.isIntValue()) break; if (parent->str() == "&") result.intvalue = value1.intvalue & value2.intvalue; else result.intvalue = value1.intvalue && value2.intvalue; setTokenValue(parent, result, settings); break; case '|': if (!value1.isIntValue() || !value2.isIntValue()) break; if (parent->str() == "|") result.intvalue = value1.intvalue | value2.intvalue; else result.intvalue = value1.intvalue || value2.intvalue; setTokenValue(parent, result, settings); break; case '^': if (!value1.isIntValue() || !value2.isIntValue()) break; result.intvalue = value1.intvalue ^ value2.intvalue; setTokenValue(parent, result, settings); break; default: // unhandled operator, do nothing break; } } } } } // ! else if (parent->str() == "!") { for (const ValueFlow::Value &val : tok->values()) { if (!val.isIntValue()) 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 == 0U || value2.varId == 0U || (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 != 0U) ? 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) 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; 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)) { ValueFlow::Value value(MathLib::toLongNumber(tok->str())); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(tok, value, settings); } else if (tok->isNumber() && MathLib::isFloat(tok->str())) { ValueFlow::Value value; value.valueType = ValueFlow::Value::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 (")) { 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 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::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() > 0U) { // array const std::map::const_iterator it = constantArrays.find(tok->varId()); if (it != constantArrays.end()) { ValueFlow::Value value; value.valueType = ValueFlow::Value::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::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::TOK; value.tokvalue = tok; setTokenValue(tok, value, tokenlist->getSettings()); } } static void valueFlowPointerAliasDeref(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()) { // TODO: Move container size values to generic forward // Forward uninit values since not all values can be forwarded directly if (!(v.isContainerSizeValue() || 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->hasKnownValue()) 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 void valueFlowTerminatingCondition(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { const bool cpp = symboldatabase->isCPP(); typedef std::pair Condition; for (const Scope * scope : symboldatabase->functionScopes) { bool skipFunction = false; std::vector conds; for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) { if (tok->isIncompleteVar()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "Skipping function due to incomplete variable " + tok->str()); skipFunction = true; break; } if (!Token::simpleMatch(tok, "if (")) continue; // Skip known values if (tok->next()->hasKnownValue()) continue; const Token * condTok = tok->next(); if (!Token::simpleMatch(condTok->link(), ") {")) continue; const Token * blockTok = condTok->link()->tokAt(1); // Check if the block terminates early if (!isEscapeScope(blockTok, tokenlist)) continue; // Check if any variables are modified in scope bool bail = false; for (const Token * tok2=condTok->next(); tok2 != condTok->link(); tok2 = tok2->next()) { const Variable * var = tok2->variable(); if (!var) continue; if (!var->scope()) continue; const Token * endToken = var->scope()->bodyEnd; if (!var->isLocal() && !var->isConst() && !var->isArgument()) { bail = true; break; } if (var->isStatic() && !var->isConst()) { bail = true; break; } if (!var->isConst() && var->declEndToken() && isVariableChanged(var->declEndToken()->next(), endToken, tok2->varId(), false, settings, cpp)) { bail = true; break; } } if (bail) continue; // TODO: Handle multiple conditions if (Token::Match(condTok->astOperand2(), "%oror%|%or%|&|&&")) continue; const Scope * condScope = nullptr; for (const Scope * parent = condTok->scope(); parent; parent = parent->nestedIn) { if (parent->type == Scope::eIf || parent->type == Scope::eWhile || parent->type == Scope::eSwitch) { condScope = parent; break; } } conds.emplace_back(condTok->astOperand2(), condScope); } if (skipFunction) break; for (Condition cond:conds) { if (!cond.first) continue; Token *const startToken = cond.first->findExpressionStartEndTokens().second->next(); for (Token* tok = startToken; tok != scope->bodyEnd; tok = tok->next()) { if (!Token::Match(tok, "%comp%")) continue; // Skip known values if (tok->hasKnownValue()) continue; if (cond.second) { bool bail = true; for (const Scope * parent = tok->scope()->nestedIn; parent; parent = parent->nestedIn) { if (parent == cond.second) { bail = false; break; } } if (bail) continue; } ErrorPath errorPath; if (isOppositeCond(true, cpp, tok, cond.first, settings->library, true, true, &errorPath)) { ValueFlow::Value val(1); val.setKnown(); val.condition = cond.first; val.errorPath = errorPath; val.errorPath.emplace_back(cond.first, "Assuming condition '" + cond.first->expressionString() + "' is false"); setTokenValue(tok, val, tokenlist->getSettings()); } else if (isSameExpression(cpp, true, tok, cond.first, settings->library, true, true, &errorPath)) { ValueFlow::Value val(0); val.setKnown(); val.condition = cond.first; val.errorPath = errorPath; val.errorPath.emplace_back(cond.first, "Assuming condition '" + cond.first->expressionString() + "' is false"); 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 void valueFlowOppositeCondition(SymbolDatabase *symboldatabase, const Settings *settings) { for (const Scope &scope : symboldatabase->scopeList) { if (scope.type != Scope::eIf) continue; Token *tok = const_cast(scope.classDef); if (!Token::simpleMatch(tok, "if (")) continue; const Token *cond1 = tok->next()->astOperand2(); if (!cond1 || !cond1->isComparisonOp()) continue; const bool cpp = symboldatabase->isCPP(); Token *tok2 = tok->linkAt(1); while (Token::simpleMatch(tok2, ") {")) { tok2 = tok2->linkAt(1); if (!Token::simpleMatch(tok2, "} else { if (")) break; Token *ifOpenBraceTok = tok2->tokAt(4); Token *cond2 = ifOpenBraceTok->astOperand2(); if (!cond2 || !cond2->isComparisonOp()) continue; if (isOppositeCond(true, cpp, cond1, cond2, settings->library, true, true)) { ValueFlow::Value value(1); value.setKnown(); setTokenValue(cond2, value, settings); } tok2 = ifOpenBraceTok->link(); } } } 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 ForwardAnalyzer::Action valueFlowForwardVariable(Token* const startToken, const Token* const endToken, const Variable* const var, std::list values, TokenList* const tokenlist, const Settings* const settings); // Old deprecated version static void valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, std::list values, const bool constValue, const bool subFunction, TokenList* const tokenlist, ErrorLogger* const errorLogger, 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) { const MathLib::bigint num = val.intvalue; const Variable * const var = varToken->variable(); if (!var) return; const int varid = varToken->varId(); const Token * const startToken = var->nameToken(); for (Token *tok2 = tok->previous(); ; tok2 = tok2->previous()) { if (!tok2 || tok2 == startToken || (tok2->str() == "{" && (tok2->scope()->type == Scope::ScopeType::eFunction || tok2->scope()->type == Scope::ScopeType::eLambda))) { break; } if (tok2->varId() == varid) { if (tok2->hasKnownValue()) break; // bailout: assignment if (Token::Match(tok2->previous(), "!!* %name% =")) { Token* assignTok = const_cast(tok2->next()->astOperand2()); if (!assignTok->hasKnownValue()) { setTokenValue(assignTok, val, settings); const std::string info = "Assignment from '" + assignTok->expressionString() + "'"; val.errorPath.emplace_back(assignTok, info); std::list values = {val}; if (val2.condition) { val2.errorPath.emplace_back(assignTok, info); setTokenValue(assignTok, val2, settings); values.push_back(val2); } const Token* startForwardToken = nextAfterAstRightmostLeaf(tok2->next()); const Token* endForwardToken = tok->scope() ? tok->scope()->bodyEnd : tok; valueFlowForward(const_cast(startForwardToken), endForwardToken, assignTok, values, false, false, tokenlist, errorLogger, settings); // Only reverse analysis supported with variables if (assignTok->varId() > 0) valueFlowReverse(tokenlist, tok2->previous(), assignTok, val, val2, errorLogger, settings); } if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str()); break; } // increment/decrement int inc = 0; if (Token::Match(tok2->previous(), "[;{}] %name% ++|-- ;")) inc = (tok2->strAt(1)=="++") ? -1 : 1; else if (Token::Match(tok2->tokAt(-2), "[;{}] ++|-- %name% ;")) inc = (tok2->strAt(-1)=="++") ? -1 : 1; else if (Token::Match(tok2->previous(), "++|-- %name%") || Token::Match(tok2, "%name% ++|--")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "increment/decrement of " + tok2->str()); break; } if (inc != 0) { val.intvalue += inc; const std::string info(tok2->str() + " is " + std::string(inc==1 ? "decremented" : "incremented") + ", before this " + (inc==1?"decrement":"increment") + " the value is " + val.infoString()); val.errorPath.emplace_back(tok2, info); } // compound assignment if (Token::Match(tok2->previous(), "[;{}] %var% %assign%") && tok2->next()->str() != "=") { const Token * const assignToken = tok2->next(); const Token * const rhsToken = assignToken->astOperand2(); if (!rhsToken || !rhsToken->hasKnownIntValue()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "compound assignment, rhs value is not known"); break; } const MathLib::bigint rhsValue = rhsToken->values().front().intvalue; if (assignToken->str() == "+=") val.intvalue -= rhsValue; else if (assignToken->str() == "-=") val.intvalue += rhsValue; else if (assignToken->str() == "*=" && rhsValue != 0) val.intvalue /= rhsValue; else { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "compound assignment " + tok2->str()); break; } const std::string info("Compound assignment '" + assignToken->str() + "', before assignment value is " + val.infoString()); val.errorPath.emplace_back(tok2, info); } // bailout: variable is used in rhs in assignment to itself if (bailoutSelfAssignment(tok2)) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + tok2->str() + " is used in rhs in assignment to itself"); break; } if (Token::Match(tok2->previous(), "sizeof|.")) { const Token *prev = tok2->previous(); while (Token::Match(prev,"%name%|.") && prev->str() != "sizeof") prev = prev->previous(); if (prev && prev->str() == "sizeof") continue; } // assigned by subfunction? bool inconclusive = false; if (isVariableChangedByFunctionCall(tok2, std::max(val.indirect, val2.indirect), settings, &inconclusive)) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction"); break; } // Impossible values can't be inconclusive if (val.isImpossible() || val2.isImpossible()) break; val.setInconclusive(inconclusive); val2.setInconclusive(inconclusive); // skip if variable is conditionally used in ?: expression if (const Token *parent = skipValueInConditionalExpression(tok2)) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "no simplification of " + tok2->str() + " within " + (Token::Match(parent,"[?:]") ? "?:" : parent->str()) + " expression"); continue; } // do-while condition, break in the loop body { const Token *parent = tok2->astParent(); while (parent && !Token::simpleMatch(parent->previous(), "while (")) parent = parent->astParent(); if (parent && Token::simpleMatch(parent->tokAt(-2), "} while (") && Token::simpleMatch(parent->linkAt(-2)->previous(), "do {")) { bool breakBailout = false; for (const Token *iftok = parent->linkAt(-2); iftok != parent; iftok = iftok->next()) { if (!Token::simpleMatch(iftok, "if (")) continue; if (!Token::simpleMatch(iftok->linkAt(1), ") { break")) continue; ProgramMemory programMemory; programMemory.setIntValue(varid, num); if (conditionIsTrue(iftok->next()->astOperand2(), programMemory)) { breakBailout = true; break; } } if (breakBailout) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "no simplification of " + tok2->str() + " in do-while condition since there is a break in the loop body"); break; } } } setTokenValue(tok2, val, settings); if (val2.condition) setTokenValue(tok2,val2, settings); if (tok2 == var->nameToken()) break; } // skip sizeof etc.. if (tok2->str() == ")" && Token::Match(tok2->link()->previous(), "sizeof|typeof|typeid (")) tok2 = tok2->link(); // goto label if (Token::Match(tok2, "[;{}] %name% :")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2->next(), "variable " + var->name() + " stopping on goto label"); break; } if (tok2->str() == "}") { const Token* condTok = getCondTokFromEnd(tok2); // Evaluate condition of for and while loops first if (condTok && condTok->astTop() && Token::Match(condTok->astTop()->previous(), "for|while (")) { const Token* startTok = nullptr; const Token* endTok = nullptr; std::tie(startTok, endTok) = condTok->findExpressionStartEndTokens(); if (!isVariableChanged(startTok, endTok, varid, false, settings, true)) { std::list values = {val}; if (val2.condition) { values.push_back(val2); } const Token *expr = Token::findmatch(tok2, "%varid%", varid); valueFlowForward(const_cast(startTok), endTok, expr, values, false, false, tokenlist, errorLogger, settings); } } const Token *vartok = Token::findmatch(tok2->link(), "%varid%", tok2, varid); while (Token::Match(vartok, "%name% = %num% ;") && !vartok->tokAt(2)->getValue(num)) vartok = Token::findmatch(vartok->next(), "%varid%", tok2, varid); if (vartok) { if (settings->debugwarnings) { std::string errmsg = "variable "; errmsg += var->name() + " "; errmsg += "stopping on }"; bailout(tokenlist, errorLogger, tok2, errmsg); } break; } else { tok2 = tok2->link(); if (Token::simpleMatch(tok2->previous(), ") {") && Token::Match(tok2->previous()->link()->previous(), "for|while (")) tok2 = tok2->previous()->link(); } } else if (tok2->str() == "{") { // if variable is assigned in loop don't look before the loop if (tok2->previous() && (Token::simpleMatch(tok2->previous(), "do") || (tok2->strAt(-1) == ")" && Token::Match(tok2->linkAt(-1)->previous(), "for|while (")))) { const Token *start = tok2; const Token *end = start->link(); if (isVariableChanged(start,end,varid,var->isGlobal(),settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " is assigned in loop. so valueflow analysis bailout when start of loop is reached."); break; } } // Global variable : stop when leaving the function scope if (!var->isLocal()) { if (!Token::Match(tok2->previous(), ")|else|do {")) break; if ((tok2->previous()->str() == ")") && !Token::Match(tok2->linkAt(-1)->previous(), "if|for|while (")) break; } } else if (tok2->str() == ";") { const Token *parent = tok2->previous(); while (parent && !Token::Match(parent, "return|break|continue|goto")) parent = parent->astParent(); // reaching a break/continue/return if (parent) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " stopping on " + parent->str()); break; } } if (Token::Match(tok2, "%name% (") && !Token::simpleMatch(tok2->linkAt(1), ") {")) { // bailout: global non-const variables if (!(var->isLocal() || var->isArgument()) && !var->isConst()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "global variable " + var->name()); return; } } } } 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 void valueFlowBeforeCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { for (const Scope * scope : symboldatabase->functionScopes) { for (Token* tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { MathLib::bigint num = 0; const Token *vartok = nullptr; if (tok->isComparisonOp() && tok->astOperand1() && tok->astOperand2()) { if (tok->astOperand1()->isName() && tok->astOperand2()->hasKnownIntValue()) { vartok = tok->astOperand1(); num = tok->astOperand2()->values().front().intvalue; } else if (tok->astOperand1()->hasKnownIntValue() && tok->astOperand2()->isName()) { vartok = tok->astOperand2(); num = tok->astOperand1()->values().front().intvalue; } else { continue; } } else if (Token::Match(tok->previous(), "if|while ( %name% %oror%|&&|)") || Token::Match(tok, "%oror%|&& %name% %oror%|&&|)")) { vartok = tok->next(); num = 0; } else if (Token::Match(tok, "[!?]") && Token::Match(tok->astOperand1(), "%name%")) { vartok = tok->astOperand1(); num = 0; } else { continue; } int varid = vartok->varId(); const Variable * const var = vartok->variable(); if (varid == 0U || !var) continue; if (tok->str() == "?" && tok->isExpandedMacro()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable " + var->name() + ", condition is defined in macro"); continue; } // bailout: for/while-condition, variable is changed in while loop for (const Token *tok2 = tok; tok2; tok2 = tok2->astParent()) { if (tok2->astParent() || tok2->str() != "(" || !Token::simpleMatch(tok2->link(), ") {")) continue; // Variable changed in 3rd for-expression if (Token::simpleMatch(tok2->previous(), "for (")) { if (tok2->astOperand2() && tok2->astOperand2()->astOperand2() && isVariableChanged(tok2->astOperand2()->astOperand2(), tok2->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) { varid = 0U; if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable " + var->name() + " used in loop"); } } // Variable changed in loop code if (Token::Match(tok2->previous(), "for|while (")) { const Token * const start = tok2->link()->next(); const Token * const end = start->link(); if (isVariableChanged(start,end,varid,var->isGlobal(),settings, tokenlist->isCPP())) { varid = 0U; if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable " + var->name() + " used in loop"); } } // if,macro => bailout else if (Token::simpleMatch(tok2->previous(), "if (") && tok2->previous()->isExpandedMacro()) { varid = 0U; if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "variable " + var->name() + ", condition is defined in macro"); } } if (varid == 0U) continue; // extra logic for unsigned variables 'i>=1' => possible value can also be 0 if (Token::Match(tok, "<|>")) { if (num != 0) continue; if (var->valueType() && var->valueType()->sign != ValueType::Sign::UNSIGNED) continue; } ValueFlow::Value val(tok, num); val.varId = varid; ValueFlow::Value val2; if (num==1U && Token::Match(tok,"<=|>=")) { if (var->isUnsigned()) { val2 = ValueFlow::Value(tok,0); val2.varId = varid; } } Token* startTok = tok->astParent() ? tok->astParent() : tok->previous(); valueFlowReverse(tokenlist, startTok, vartok, val, val2, errorLogger, settings); } } } static void valueFlowAST(Token *tok, nonneg int varid, const ValueFlow::Value &value, const Settings *settings) { if (!tok) return; if (tok->varId() == varid) setTokenValue(tok, value, settings); valueFlowAST(tok->astOperand1(), varid, value, settings); if (tok->str() == "&&" && tok->astOperand1() && tok->astOperand1()->getValue(0)) { ProgramMemory pm; pm.setValue(varid,value); if (conditionIsFalse(tok->astOperand1(), pm)) return; } else if (tok->str() == "||" && tok->astOperand1()) { const std::list &values = tok->astOperand1()->values(); const bool nonzero = std::any_of(values.cbegin(), values.cend(), [=](const ValueFlow::Value &v) { return v.intvalue != 0; }); if (!nonzero) return; ProgramMemory pm; pm.setValue(varid,value); if (conditionIsTrue(tok->astOperand1(), pm)) return; } valueFlowAST(tok->astOperand2(), varid, value, settings); } static bool evalAssignment(ValueFlow::Value &lhsValue, const std::string &assign, const ValueFlow::Value &rhsValue) { if (lhsValue.isIntValue()) { if (assign == "=") lhsValue.intvalue = rhsValue.intvalue; else if (assign == "+=") lhsValue.intvalue += rhsValue.intvalue; else if (assign == "-=") lhsValue.intvalue -= rhsValue.intvalue; else if (assign == "*=") lhsValue.intvalue *= rhsValue.intvalue; else if (assign == "/=") { if (rhsValue.intvalue == 0) return false; lhsValue.intvalue /= rhsValue.intvalue; } else if (assign == "%=") { if (rhsValue.intvalue == 0) return false; lhsValue.intvalue %= rhsValue.intvalue; } else if (assign == "&=") lhsValue.intvalue &= rhsValue.intvalue; else if (assign == "|=") lhsValue.intvalue |= rhsValue.intvalue; else if (assign == "^=") lhsValue.intvalue ^= rhsValue.intvalue; else if (assign == "<<=") { if (rhsValue.intvalue < 0) return false; lhsValue.intvalue <<= rhsValue.intvalue; } else if (assign == ">>=") { if (rhsValue.intvalue < 0) return false; lhsValue.intvalue >>= rhsValue.intvalue; } else return false; } else if (lhsValue.isFloatValue()) { if (assign == "=") lhsValue.intvalue = rhsValue.intvalue; else if (assign == "+=") lhsValue.floatValue += rhsValue.intvalue; else if (assign == "-=") lhsValue.floatValue -= rhsValue.intvalue; else if (assign == "*=") lhsValue.floatValue *= rhsValue.intvalue; else if (assign == "/=") lhsValue.floatValue /= rhsValue.intvalue; else return false; } else { return false; } return true; } // Check if its an alias of the variable or is being aliased to this variable static bool isAliasOf(const Variable * var, const Token *tok, nonneg int varid, const std::list& 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 const ValueFlow::Value* getKnownValue(const Token* tok, ValueFlow::Value::ValueType type) { if (!tok) return nullptr; auto it = std::find_if(tok->values().begin(), tok->values().end(), [&](const ValueFlow::Value& v) { return v.isKnown() && v.valueType == type; }); if (it != tok->values().end()) return &*it; return nullptr; } static bool bifurcate(const Token* tok, const std::set& varids, const Settings* settings, int depth = 20) { 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() || !isVariableChanged(start->next(), tok, var->declarationId(), var->isGlobal(), settings, true)) return var->isArgument() || bifurcate(start->astOperand2(), varids, settings, depth - 1); return false; } return false; } struct SelectMapKeys { template typename Pair::first_type operator()(const Pair& p) const { return p.first; } }; struct SelectMapValues { template typename Pair::second_type operator()(const Pair& p) const { return p.second; } }; struct ValueFlowForwardAnalyzer : ForwardAnalyzer { const TokenList* tokenlist; ProgramMemoryState pms; ValueFlowForwardAnalyzer() : tokenlist(nullptr), pms() {} ValueFlowForwardAnalyzer(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 invalid() const { return false; } bool isCPP() const { return tokenlist->isCPP(); } const Settings* getSettings() const { return tokenlist->getSettings(); } 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; return Action::Invalid; } return read; } virtual Action isAliasModified(const Token* tok) const { int indirect = 0; int baseIndirect = 0; const ValueType* vt = getValueType(tok); if (vt) baseIndirect = vt->pointer; if (tok->valueType()) indirect = std::max(0, tok->valueType()->pointer - baseIndirect); if (isVariableChanged(tok, indirect, getSettings(), isCPP())) return Action::Invalid; return Action::None; } virtual Action isWritable(const Token* tok) const { const ValueFlow::Value* value = getValue(tok); if (!value) return Action::None; if (!(value->isIntValue() || value->isFloatValue())) 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 = getKnownValue(rhs, ValueFlow::Value::ValueType::INT); Action a; if (!rhsValue) a = Action::Invalid; else a = Action::Write; if (parent->str() != "=") a |= Action::Read; return a; } // increment/decrement if (Token::Match(tok->previous(), "++|-- %name%") || Token::Match(tok, "%name% ++|--")) { return Action::Read | Action::Write; } return Action::None; } virtual void writeValue(ValueFlow::Value* value, const Token* tok) const { if (!value) return; if (!tok->astParent()) return; if (tok->astParent()->isAssignmentOp()) { // TODO: Check result if (evalAssignment(*value, tok->astParent()->str(), *getKnownValue(tok->astParent()->astOperand2(), ValueFlow::Value::ValueType::INT))) { 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 { // TODO: Don't set to zero value->intvalue = 0; } } else if (tok->astParent()->tokType() == Token::eIncDecOp) { const bool inc = tok->astParent()->str() == "++"; value->intvalue += (inc ? 1 : -1); const std::string info(tok->str() + " is " + std::string(inc ? "incremented" : "decremented") + "', new value is " + value->infoString()); value->errorPath.emplace_back(tok, info); } } virtual Action analyze(const Token* tok) const OVERRIDE { if (invalid()) return Action::Invalid; bool inconclusive = false; if (match(tok)) { const Token* parent = tok->astParent(); if (astIsPointer(tok) && (Token::Match(parent, "*|[") || (parent && parent->originalName() == "->")) && getIndirect(tok) <= 0) return Action::Read; // Action read = Action::Read; Action w = isWritable(tok); if (w != Action::None) return w; // Check for modifications by function calls return isModified(tok); } else if (tok->isUnaryOp("*")) { const Token* lifeTok = nullptr; for (const ValueFlow::Value& v:tok->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::Read; return a; } return Action::None; } else if (isAlias(tok, inconclusive)) { Action a = isAliasModified(tok); if (inconclusive && a.isModified()) return Action::Inconclusive; else return a; } else if (Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) { // bailout: global non-const variables if (isGlobal()) { return Action::Invalid; } } return Action::None; } virtual std::vector evaluate(const Token* tok) const OVERRIDE { if (tok->hasKnownIntValue()) return {static_cast(tok->values().front().intvalue)}; std::vector result; ProgramMemory pm = pms.get(tok, getProgramState()); if (conditionIsTrue(tok, pm)) result.push_back(1); if (conditionIsFalse(tok, pm)) result.push_back(0); return result; } virtual void assume(const Token* tok, bool state, const Token* at) OVERRIDE { // Update program state pms.removeModifiedVars(tok); pms.addState(tok, getProgramState()); pms.assume(tok, state); const bool isAssert = Token::Match(at, "assert|ASSERT"); if (!isAssert && !Token::simpleMatch(at, "}")) { std::string s = state ? "true" : "false"; addErrorPath(tok, "Assuming condition is " + s); } if (!isAssert) makeConditional(); } virtual void update(Token* tok, Action a) OVERRIDE { ValueFlow::Value* value = getValue(tok); if (!value) return; if (a.isRead()) setTokenValue(tok, *value, getSettings()); if (a.isInconclusive()) lowerToInconclusive(); if (a.isWrite() && tok->astParent()) { writeValue(value, tok); } } }; struct SingleValueFlowForwardAnalyzer : ValueFlowForwardAnalyzer { std::unordered_map varids; std::unordered_map aliases; ValueFlow::Value value; SingleValueFlowForwardAnalyzer() : ValueFlowForwardAnalyzer() {} SingleValueFlowForwardAnalyzer(const ValueFlow::Value& v, const TokenList* t) : ValueFlowForwardAnalyzer(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 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, {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.isImpossible(); return false; } 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; } }; struct VariableForwardAnalyzer : SingleValueFlowForwardAnalyzer { const Variable* var; VariableForwardAnalyzer() : SingleValueFlowForwardAnalyzer(), var(nullptr) {} VariableForwardAnalyzer(const Variable* v, const ValueFlow::Value& val, std::vector paliases, const TokenList* t) : SingleValueFlowForwardAnalyzer(val, t), var(v) { varids[var->declarationId()] = var; for (const Variable* av:paliases) { if (!av) continue; aliases[av->declarationId()] = av; } } virtual const ValueType* getValueType(const Token*) const OVERRIDE { return var->valueType(); } virtual bool match(const Token* tok) const OVERRIDE { return tok->varId() == var->declarationId(); } virtual ProgramState getProgramState() const OVERRIDE { ProgramState ps; ps[var->declarationId()] = value; return ps; } }; static std::vector getAliasesFromValues(std::list values, bool address=false) { std::vector aliases; for (const ValueFlow::Value& v : values) { if (!v.tokvalue) continue; const Token* lifeTok = nullptr; for (const ValueFlow::Value& lv:v.tokvalue->values()) { if (!lv.isLocalLifetimeValue()) continue; if (address && lv.lifetimeKind != ValueFlow::Value::LifetimeKind::Address) continue; if (lifeTok) { lifeTok = nullptr; break; } lifeTok = lv.tokvalue; } if (lifeTok && lifeTok->variable()) { aliases.push_back(lifeTok->variable()); } } return aliases; } static ForwardAnalyzer::Action valueFlowForwardVariable(Token* const startToken, const Token* const endToken, const Variable* const var, std::list values, std::vector aliases, TokenList* const tokenlist, const Settings* const settings) { ForwardAnalyzer::Action actions; for (ValueFlow::Value& v : values) { VariableForwardAnalyzer a(var, v, aliases, tokenlist); actions |= valueFlowGenericForward(startToken, endToken, a, settings); } return actions; } static ForwardAnalyzer::Action valueFlowForwardVariable(Token* const startToken, const Token* const endToken, const Variable* const var, std::list values, TokenList* const tokenlist, const Settings* const settings) { return valueFlowForwardVariable( startToken, endToken, var, std::move(values), getAliasesFromValues(values), tokenlist, settings); } // Old deprecated version static bool valueFlowForwardVariable(Token* const startToken, const Token* const endToken, const Variable* const var, const nonneg int, std::list values, const bool, const bool, TokenList* const tokenlist, ErrorLogger* const, const Settings* const settings) { valueFlowForwardVariable(startToken, endToken, var, std::move(values), tokenlist, settings); return true; } struct ExpressionForwardAnalyzer : SingleValueFlowForwardAnalyzer { const Token* expr; bool local; bool unknown; ExpressionForwardAnalyzer() : SingleValueFlowForwardAnalyzer(), expr(nullptr), local(true), unknown(false) {} ExpressionForwardAnalyzer(const Token* e, const ValueFlow::Value& val, const TokenList* t) : SingleValueFlowForwardAnalyzer(val, t), expr(e), local(true), unknown(false) { setupExprVarIds(); } 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() { visitAstNodes(expr, [&](const Token *tok) { if (tok->varId() == 0 && 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 std::vector evaluate(const Token* tok) const OVERRIDE { if (tok->hasKnownIntValue()) return {static_cast(tok->values().front().intvalue)}; return std::vector {}; } virtual bool match(const Token* tok) const OVERRIDE { return isSameExpression(isCPP(), true, expr, tok, getSettings()->library, true, true); } virtual ProgramState getProgramState() const OVERRIDE { return ProgramState{}; } virtual bool isGlobal() const OVERRIDE { return !local; } }; static ForwardAnalyzer::Action valueFlowForwardExpression(Token* startToken, const Token* endToken, const Token* exprTok, const std::list& values, const TokenList* const tokenlist, const Settings* settings) { ForwardAnalyzer::Action actions; for (const ValueFlow::Value& v : values) { ExpressionForwardAnalyzer a(exprTok, v, tokenlist); actions |= valueFlowGenericForward(startToken, endToken, a, settings); } return actions; } static const Token* parseBinaryIntOp(const Token* expr, MathLib::bigint& known) { if (!expr) return nullptr; if (!expr->astOperand1() || !expr->astOperand2()) 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; } template void transformIntValues(std::list& values, F f) { std::transform(values.begin(), values.end(), values.begin(), [&](ValueFlow::Value x) { if (x.isIntValue() || x.isIteratorValue()) x.intvalue = f(x.intvalue); return x; }); } static const Token* solveExprValues(const Token* expr, std::list& values) { MathLib::bigint intval; const Token* binaryTok = parseBinaryIntOp(expr, intval); if (binaryTok && expr->str().size() == 1) { switch (expr->str()[0]) { case '+': { transformIntValues(values, [&](MathLib::bigint x) { return x - intval; }); return solveExprValues(binaryTok, values); } case '*': { if (intval == 0) break; transformIntValues(values, [&](MathLib::bigint x) { return x / intval; }); return solveExprValues(binaryTok, values); } case '^': { transformIntValues(values, [&](MathLib::bigint x) { return x ^ intval; }); return solveExprValues(binaryTok, values); } } } return expr; } static ForwardAnalyzer::Action valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, std::list values, TokenList* const tokenlist, const Settings* settings) { const Token* expr = solveExprValues(exprTok, values); if (expr->variable()) { return valueFlowForwardVariable(startToken, endToken, expr->variable(), values, tokenlist, settings); } else { return valueFlowForwardExpression(startToken, endToken, expr, values, tokenlist, settings); } } // Old deprecated version static void valueFlowForward(Token* startToken, const Token* endToken, const Token* exprTok, std::list values, const bool, const bool, TokenList* const tokenlist, ErrorLogger* const, const Settings* settings) { valueFlowForward(startToken, endToken, exprTok, std::move(values), tokenlist, settings); } static int getArgumentPos(const Variable *var, const Function *f) { auto arg_it = std::find_if(f->argumentList.begin(), f->argumentList.end(), [&](const Variable &v) { return v.nameToken() == var->nameToken(); }); if (arg_it == f->argumentList.end()) return -1; return std::distance(f->argumentList.begin(), arg_it); } 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; } ValueFlow::Value getLifetimeObjValue(const Token *tok, bool inconclusive) { ValueFlow::Value result; auto pred = [&](const ValueFlow::Value &v) { if (!v.isLocalLifetimeValue()) return false; if (!inconclusive && v.isInconclusive()) return false; if (!v.tokvalue->variable()) return false; return true; }; auto it = std::find_if(tok->values().begin(), tok->values().end(), pred); if (it == tok->values().end()) return result; result = *it; // There should only be one lifetime if (std::find_if(std::next(it), tok->values().end(), pred) != tok->values().end()) return ValueFlow::Value{}; return result; } std::vector getLifetimeTokens(const Token* tok, bool escape, ValueFlow::Value::ErrorPath errorPath, int depth) { if (!tok) return std::vector {}; const Variable *var = tok->variable(); 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(); if (vartok == tok || (!escape && var->isConst() && isTemporary(true, vartok, nullptr, true))) return {{tok, true, std::move(errorPath)}}; if (vartok) return getLifetimeTokens(vartok, escape, std::move(errorPath), 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), 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, std::move(errorPath), depth - 1)) { 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), depth - 1), 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), depth - 1), false); } } } else if (Token::Match(tok, ".|::|[")) { const Token *vartok = tok; 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(); if (!astIsContainer(vartok) && !(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), depth - 1); } } else { return LifetimeToken::setAddressOf(getLifetimeTokens(vartok, escape, std::move(errorPath), depth - 1), !(astIsContainer(vartok) && Token::simpleMatch(vartok->astParent(), "["))); } } return {{tok, std::move(errorPath)}}; } 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->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); } 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%")) { const Type *t = Token::typeOf(tok); const Type *parentT = Token::typeOf(tok->astParent()); if (t && parentT) { if (t->classDef && parentT->classDef && t->classDef != parentT->classDef) return false; } else { std::pair decl = Token::typeDecl(tok); std::pair parentdecl = Token::typeDecl(tok->astParent()); if (isNotEqual(decl, parentdecl)) return false; if (isNotEqual(decl, tok->astParent()->valueType())) return false; if (isNotEqual(parentdecl, tok->valueType())) 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()) 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) { valueFlowForwardVariable(const_cast(nextExpression), endOfVarScope, var, var->declarationId(), values, false, false, tokenlist, errorLogger, settings); if (tok->astTop() && Token::simpleMatch(tok->astTop()->previous(), "for (") && Token::simpleMatch(tok->astTop()->link(), ") {")) { Token* start = tok->astTop()->link()->next(); valueFlowForwardVariable( start, start->link(), var, var->declarationId(), values, false, false, tokenlist, errorLogger, 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); valueFlowForwardVariable(const_cast(nextExpression), endOfVarScope, var, var->declarationId(), values, false, false, tokenlist, errorLogger, settings); } } struct LifetimeStore { const Token *argtok; std::string message; ValueFlow::Value::LifetimeKind type; ErrorPath errorPath; bool inconclusive; LifetimeStore() : argtok(nullptr), message(), type(), errorPath(), inconclusive(false) {} 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) {} 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 void byRef(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const { if (!argtok) return; for (const LifetimeToken& lt : getLifetimeTokens(argtok)) { if (!settings->inconclusive && lt.inconclusive) continue; ErrorPath er = errorPath; er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end()); if (!lt.token) return; if (!pred(lt.token)) return; er.emplace_back(argtok, message); ValueFlow::Value value; value.valueType = ValueFlow::Value::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; setTokenValue(tok, value, tokenlist->getSettings()); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } void byRef(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const { byRef(tok, tokenlist, errorLogger, settings, [](const Token *) { return true; }); } template void byVal(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const { if (!argtok) return; 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::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; setTokenValue(tok, value, tokenlist->getSettings()); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok3 = v.tokvalue; for (const LifetimeToken& lt : getLifetimeTokens(tok3)) { if (!settings->inconclusive && lt.inconclusive) continue; ErrorPath er = v.errorPath; er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end()); if (!lt.token) return; if (!pred(lt.token)) return; er.emplace_back(argtok, message); er.insert(er.end(), errorPath.begin(), errorPath.end()); ValueFlow::Value value; value.valueType = ValueFlow::Value::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()); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } } } void byVal(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const { 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->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; }); } }; 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; 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.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.inconclusive = inconclusive; ls.errorPath = v.errorPath; ls.errorPath.emplace_front(returnTok, "Return " + lifetimeType(returnTok, &v) + "."); if (!v.isArgumentLifetimeValue() && (var->isReference() || var->isRValueReference())) { ls.byRef(tok->next(), tokenlist, errorLogger, settings); } else if (v.isArgumentLifetimeValue()) { ls.byVal(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); for (const Token *argtok : args) { LifetimeStore ls{argtok, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::Object}; 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); std::size_t i = 0; for (const Variable& var : scope->varlist) { if (i >= args.size()) break; const Token* argtok = args[i]; LifetimeStore ls{ argtok, "Passed to constructor of '" + t->name() + "'.", ValueFlow::Value::LifetimeKind::Object}; if (var.isReference() || var.isRValueReference()) { ls.byRef(tok, tokenlist, errorLogger, settings); } else { ls.byVal(tok, tokenlist, errorLogger, settings); } i++; } } } 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])) { for (const Token *argtok : args) { LifetimeStore ls{argtok, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::Object}; ls.byDerefCopy(tok, tokenlist, errorLogger, settings); } } else { for (const Token *argtok : args) { LifetimeStore ls{argtok, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::Object}; ls.byVal(tok, tokenlist, errorLogger, settings); } } } else { valueFlowLifetimeConstructor(tok, Token::typeOf(tok->previous()), tokenlist, errorLogger, settings); } } struct Lambda { enum class Capture { ByValue, ByReference }; explicit Lambda(const Token * tok) : capture(nullptr), arguments(nullptr), returnTok(nullptr), bodyTok(nullptr), explicitCaptures() { 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; }; 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{tok2, "Lambda captures variable by reference here.", ValueFlow::Value::LifetimeKind::Lambda} .byRef( tok, tokenlist, errorLogger, settings, pred); } else if (c == Lambda::Capture::ByValue) { LifetimeStore{tok2, "Lambda captures variable by value here.", ValueFlow::Value::LifetimeKind::Lambda} .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); } valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } // address of else if (tok->isUnaryOp("&")) { for (const LifetimeToken& lt : getLifetimeTokens(tok->astOperand1())) { if (!settings->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, ErrorLogger *errorLogger, 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 int varId = varTok->varId(); const Token * const endOfVarScope = var->scope()->bodyEnd; setTokenValue(varTok, value, settings); valueFlowForwardVariable( varTok->next(), endOfVarScope, var, varId, values, false, false, tokenlist, errorLogger, settings); continue; } ValueFlow::Value::MoveKind moveKind; if (!isStdMoveOrStdForwarded(tok, &moveKind, &varTok)) continue; const 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) valueFlowForwardVariable(const_cast(endOfFunctionCall), endOfVarScope, var, varId, values, false, false, tokenlist, errorLogger, settings); } } } static void valueFlowForwardAssign(Token * const tok, const Variable * const var, std::list values, const bool constValue, const bool init, TokenList * const tokenlist, ErrorLogger * const errorLogger, const Settings * const settings) { const Token * endOfVarScope = nullptr; if (var->isLocal()) endOfVarScope = var->scope()->bodyEnd; if (!endOfVarScope) endOfVarScope = tok->scope()->bodyEnd; 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 (!var->isPointer() && !var->isSmartPointer()) values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue)); if (tok->astParent()) { for (std::list::iterator it = values.begin(); it != values.end(); ++it) { const std::string info = "Assignment '" + tok->astParent()->expressionString() + "', assigned value is " + it->infoString(); it->errorPath.emplace_back(tok, info); } } if (tokenlist->isCPP() && Token::Match(var->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 (var->isStatic() && init) lowerToPossible(values); // Skip RHS const Token * nextExpression = tok->astParent() ? nextAfterAstRightmostLeaf(tok->astParent()) : tok->next(); if (std::any_of(values.begin(), values.end(), std::mem_fn(&ValueFlow::Value::isTokValue))) { std::list tokvalues; std::copy_if(values.begin(), values.end(), std::back_inserter(tokvalues), std::mem_fn(&ValueFlow::Value::isTokValue)); valueFlowForwardVariable(const_cast(nextExpression), endOfVarScope, var, var->declarationId(), tokvalues, constValue, false, tokenlist, errorLogger, settings); values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue)); } for (ValueFlow::Value& value:values) value.tokvalue = tok; valueFlowForwardVariable(const_cast(nextExpression), endOfVarScope, var, var->declarationId(), values, constValue, false, tokenlist, errorLogger, settings); } static std::list truncateValues(std::list values, const ValueType *valueType, const Settings *settings) { if (!valueType || !valueType->isIntegral()) return values; const size_t sz = ValueFlow::getSizeOf(*valueType, settings); for (ValueFlow::Value &value : values) { if (value.isFloatValue()) { value.intvalue = value.floatValue; value.valueType = ValueFlow::Value::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 (valueType->sign == ValueType::Sign::SIGNED && (value.intvalue & signBit)) value.intvalue |= ~unsignedMaxValue; } } return values; } static bool isLiteralNumber(const Token *tok, bool cpp) { return tok->isNumber() || tok->isEnumerator() || tok->str() == "NULL" || (cpp && Token::Match(tok, "false|true|nullptr")); } 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()->varId()); continue; } // Assignment if ((tok->str() != "=" && !isVariableInit(tok)) || (tok->astParent())) continue; // Lhs should be a variable if (!tok->astOperand1() || !tok->astOperand1()->varId()) continue; const int varid = tok->astOperand1()->varId(); if (aliased.find(varid) != aliased.end()) continue; const Variable *var = tok->astOperand1()->variable(); if (!var || (!var->isLocal() && !var->isGlobal() && !var->isArgument())) continue; // Rhs values.. if (!tok->astOperand2() || tok->astOperand2()->values().empty()) continue; std::list values = truncateValues(tok->astOperand2()->values(), tok->astOperand1()->valueType(), settings); // Remove known values std::set types; if (tok->astOperand1()->hasKnownValue()) { for (const ValueFlow::Value& value:tok->astOperand1()->values()) { if (value.isKnown()) 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::CONTAINER_SIZE; }); if (values.empty()) continue; const bool constValue = isLiteralNumber(tok->astOperand2(), tokenlist->isCPP()); const bool init = var->nameToken() == tok->astOperand1(); valueFlowForwardAssign(tok->astOperand2(), var, values, constValue, 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); } } static std::vector getExprVariables(const Token* expr, const TokenList* tokenlist, const SymbolDatabase* symboldatabase, const Settings* settings) { std::vector result; FwdAnalysis fwdAnalysis(tokenlist->isCPP(), settings->library); std::set varids = fwdAnalysis.getExprVarIds(expr); std::transform(varids.begin(), varids.end(), std::back_inserter(result), [&](int id) { return symboldatabase->getVariableFromVarId(id); }); return result; } struct ValueFlowConditionHandler { struct Condition { const Token *vartok; std::list true_values; std::list false_values; bool inverted = false; Condition() : vartok(nullptr), true_values(), false_values(), inverted(false) {} }; std::function& values, bool constValue)> forward; std::function parse; void afterCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings) const { for (const Scope *scope : symboldatabase->functionScopes) { std::set aliased; for (Token *tok = const_cast(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) { if (Token::Match(tok, "if|while|for (")) continue; if (Token::Match(tok, "= & %var% ;")) aliased.insert(tok->tokAt(2)->varId()); const Token* top = tok->astTop(); if (!top) continue; if (!Token::Match(top->previous(), "if|while|for (") && !Token::Match(tok->astParent(), "&&|%oror%")) continue; Condition cond = parse(tok); if (!cond.vartok) continue; if (cond.vartok->variable() && cond.vartok->variable()->isVolatile()) continue; if (cond.true_values.empty() || cond.false_values.empty()) continue; if (exprDependsOnThis(cond.vartok)) continue; std::vector vars = getExprVariables(cond.vartok, tokenlist, symboldatabase, settings); if (std::any_of(vars.begin(), vars.end(), [](const Variable* var) { return !var; })) continue; if (!vars.empty() && (vars.front())) if (std::any_of(vars.begin(), vars.end(), [&](const Variable* var) { return var && aliased.find(var->declarationId()) != aliased.end(); })) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, cond.vartok, "variable is aliased so we just skip all valueflow after condition"); continue; } 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 (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 (isConditionKnown(tok, true)) { insertImpossible(thenValues, cond.true_values); if (Token::Match(tok, "(|.|%var%") && 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) && parent->astParent() && parent->str() == parent->astParent()->str()) parent = parent->astParent(); else if (!astIsLHS(tok)) { parent = nullptr; } if (parent) { const std::string &op(parent->str()); std::list values; if (op == "&&") values = thenValues; else if (op == "||") values = elseValues; if (Token::Match(tok, "==|!=")) changePossibleToKnown(values); if (!values.empty()) { bool assign = false; visitAstNodes(parent->astOperand2(), [&](Token* tok2) { if (tok2 == tok) return ChildrenToVisit::done; if (isSameExpression(tokenlist->isCPP(), false, cond.vartok, tok2, settings->library, true, false)) setTokenValue(tok2, values.front(), settings); else if (Token::Match(tok2, "++|--|=") && isSameExpression(tokenlist->isCPP(), false, cond.vartok, tok2->astOperand1(), settings->library, true, false)) { assign = true; return ChildrenToVisit::done; } return ChildrenToVisit::op1_and_op2; }); if (assign) break; } } } { 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) { continue; } } if (top && Token::Match(top->previous(), "if|while (") && !top->previous()->isExpandedMacro()) { // does condition reassign variable? if (tok != top->astOperand2() && Token::Match(top->astOperand2(), "%oror%|&&") && isVariablesChanged(top, top->link(), 0, vars, settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "assignment in condition"); continue; } // start token of conditional code Token* startTokens[] = {nullptr, nullptr}; // 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; } } // 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); // TODO: The endToken should not be startTokens[i]->link() in the valueFlowForwardVariable call if (forward(startTokens[i], startTokens[i]->link(), cond.vartok, values, true)) changeBlock = i; changeKnownToPossible(values); } // TODO: Values changed in noreturn blocks should not bail 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"); continue; } // After conditional code.. if (Token::simpleMatch(top->link(), ") {")) { Token *after = top->link()->linkAt(1); const Token* unknownFunction = nullptr; const bool isWhile = tok->astParent() && Token::simpleMatch(tok->astParent()->previous(), "while ("); bool dead_if = (!isBreakScope(after) && isWhile) || (isReturnScope(after, &settings->library, &unknownFunction) && !isWhile); bool dead_else = false; if (!dead_if && unknownFunction) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope"); continue; } if (Token::simpleMatch(after, "} else {")) { after = after->linkAt(2); unknownFunction = nullptr; dead_else = isReturnScope(after, &settings->library, &unknownFunction); if (!dead_else && unknownFunction) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope"); continue; } } if (dead_if && dead_else) continue; 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()) { if ((dead_if || dead_else) && !Token::Match(tok->astParent(), "&&|&")) { valueFlowSetConditionToKnown(tok, values, true); valueFlowSetConditionToKnown(tok, values, false); } // TODO: constValue could be true if there are no assignments in the conditional blocks and // perhaps if there are no && and no || in the condition bool constValue = false; forward(after, scope->bodyEnd, cond.vartok, values, constValue); } } } } } } }; static void valueFlowAfterCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { ValueFlowConditionHandler handler; handler.forward = [&](Token* start, const Token* stop, const Token* vartok, const std::list& values, bool) { return valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings).isModified(); }; handler.parse = [&](const Token *tok) { ValueFlowConditionHandler::Condition cond; ValueFlow::Value true_value; ValueFlow::Value false_value; const Token *vartok = parseCompareInt(tok, true_value, false_value); if (vartok) { 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; cond.true_values.emplace_back(tok, 0LL); cond.false_values.emplace_back(tok, 0LL); cond.vartok = vartok; return cond; }; handler.afterCondition(tokenlist, symboldatabase, errorLogger, settings); } 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::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; } static void valueFlowInferCondition(TokenList* tokenlist, const Settings* settings) { for (Token* tok = tokenlist->front(); tok; tok = tok->next()) { if (!tok->astParent()) continue; if (tok->hasKnownValue()) 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()) { MathLib::bigint val = 0; const Token* varTok = nullptr; std::string op = tok->str(); if (tok->astOperand1()->hasKnownIntValue()) { val = tok->astOperand1()->values().front().intvalue; varTok = tok->astOperand2(); // Flip the operator if (op == ">") op = "<"; else if (op == "<") op = ">"; else if (op == ">=") op = "<="; else if (op == "<=") op = ">="; } else if (tok->astOperand2()->hasKnownIntValue()) { val = tok->astOperand2()->values().front().intvalue; varTok = tok->astOperand1(); } if (!varTok) continue; if (varTok->hasKnownIntValue()) continue; if (varTok->values().empty()) continue; 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) continue; ValueFlow::Value value = *result; value.intvalue = known; value.bound = ValueFlow::Value::Bound::Point; value.setKnown(); setTokenValue(tok, value, settings); } } } 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); } memory1->swap(startMemory); if (!error) { memory2->swap(endMemory); 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, ErrorLogger *errorLogger, 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) { valueFlowForwardVariable( blockTok->next(), endToken, var, varid, values, false, false, tokenlist, errorLogger, 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; if (executeBody) { valueFlowForLoopSimplify(bodyStart, varid, false, initValue, tokenlist, errorLogger, settings); if (stepValue == 1) valueFlowForLoopSimplify(bodyStart, varid, false, lastValue, tokenlist, errorLogger, settings); } const MathLib::bigint afterValue = executeBody ? lastValue + stepValue : initValue; valueFlowForLoopSimplifyAfter(tok, varid, afterValue, tokenlist, errorLogger, 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, errorLogger, settings); } } } } } struct MultiValueFlowForwardAnalyzer : ValueFlowForwardAnalyzer { std::unordered_map values; std::unordered_map vars; MultiValueFlowForwardAnalyzer() : ValueFlowForwardAnalyzer(), values(), vars() {} MultiValueFlowForwardAnalyzer(const std::unordered_map& args, const TokenList* t) : ValueFlowForwardAnalyzer(t), values(), vars() { 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 { std::list vals; std::transform(values.begin(), values.end(), std::back_inserter(vals), SelectMapValues{}); 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, vals, &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 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; } }; static void valueFlowInjectParameter(TokenList* tokenlist, 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; MultiValueFlowForwardAnalyzer a(arg, tokenlist); valueFlowGenericForward(const_cast(functionScope->bodyStart), functionScope->bodyEnd, a, settings); } } static void valueFlowInjectParameter(TokenList* tokenlist, ErrorLogger* errorLogger, 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 int varid2 = arg->declarationId(); if (!varid2) return; valueFlowForwardVariable(const_cast(functionScope->bodyStart->next()), functionScope->bodyEnd, arg, varid2, argvalues, false, true, tokenlist, errorLogger, 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::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) { for (const Scope* scope : symboldatabase->functionScopes) { const Function* function = scope->function; if (!function) continue; int id = 0; 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)); 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; // Change scope of lifetime values if (v.isLifetimeValue()) v.lifetimeScope = ValueFlow::Value::LifetimeScope::SubFunction; } // passed values are not "known".. lowerToPossible(argvalues); argvars[argvar] = argvalues; } valueFlowInjectParameter(tokenlist, errorLogger, settings, calledFunctionScope, argvars); } } } static void valueFlowFunctionDefaultParameter(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, 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, errorLogger, 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*/, ErrorLogger *errorLogger, 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::UNINIT; uninitValue.tokvalue = vardecl; std::list values; values.push_back(uninitValue); const bool constValue = true; const bool subFunction = false; valueFlowForwardVariable(vardecl->next(), vardecl->scope()->bodyEnd, var, vardecl->varId(), values, constValue, subFunction, tokenlist, errorLogger, settings); } } static bool hasContainerSizeGuard(const Token *tok, nonneg int containerId) { for (; tok && tok->astParent(); tok = tok->astParent()) { const Token *parent = tok->astParent(); if (tok != parent->astOperand2()) continue; if (!Token::Match(parent, "%oror%|&&|?")) continue; // is container found in lhs? bool found = false; visitAstNodes(parent->astOperand1(), [&](const Token *t) { if (t->varId() == containerId) found = true; return found ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2; }); if (found) return true; } return false; } 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) { 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); } static void valueFlowContainerReverse(Token *tok, nonneg int containerId, const ValueFlow::Value &value, const Settings *settings) { while (nullptr != (tok = tok->previous())) { if (Token::Match(tok, "[{}]")) break; if (Token::Match(tok, "return|break|continue")) break; if (tok->varId() != containerId) continue; if (Token::Match(tok, "%name% =")) break; if (isContainerSizeChangedByFunction(tok)) break; if (!tok->valueType() || !tok->valueType()->container) break; if (Token::Match(tok, "%name% . %name% (") && tok->valueType()->container->getAction(tok->strAt(2)) != Library::Container::Action::NO_ACTION) break; if (!hasContainerSizeGuard(tok, containerId)) setTokenValue(tok, value, settings); } } struct ContainerVariableForwardAnalyzer : VariableForwardAnalyzer { ContainerVariableForwardAnalyzer() : VariableForwardAnalyzer() {} ContainerVariableForwardAnalyzer(const Variable* v, const ValueFlow::Value& val, std::vector paliases, const TokenList* t) : VariableForwardAnalyzer(v, val, std::move(paliases), t) {} virtual bool match(const Token* tok) const OVERRIDE { return tok->varId() == var->declarationId() || (astIsIterator(tok) && isAliasOf(tok, var->declarationId())); } virtual Action isWritable(const Token* tok) const OVERRIDE { if (astIsIterator(tok)) return Action::None; const ValueFlow::Value* value = getValue(tok); if (!value) 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; 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; } } 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) return Action::Read | Action::Write; } return Action::None; } virtual void writeValue(ValueFlow::Value* value, const Token* tok) const OVERRIDE { if (!value) 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) value->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()) { value->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) value->intvalue++; if (action == Library::Container::Action::POP) value->intvalue--; } } virtual Action isModified(const Token* tok) const OVERRIDE { Action read = Action::Read; // An iterator wont 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 (isContainerSizeChanged(tok)) return Action::Invalid; return read; } }; static ForwardAnalyzer::Action valueFlowContainerForward(Token* tok, const Token* endToken, const Variable* var, ValueFlow::Value value, TokenList* tokenlist) { ContainerVariableForwardAnalyzer a(var, value, getAliasesFromValues({value}), tokenlist); return valueFlowGenericForward(tok, endToken, a, tokenlist->getSettings()); } static ForwardAnalyzer::Action valueFlowContainerForward(Token* tok, const Variable* var, ValueFlow::Value value, TokenList* tokenlist) { const Token * endOfVarScope = nullptr; if (var->isLocal() || var->isArgument()) endOfVarScope = var->scope()->bodyEnd; if (!endOfVarScope) endOfVarScope = tok->scope()->bodyEnd; return valueFlowContainerForward(tok, endOfVarScope, var, std::move(value), tokenlist); } 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(4), 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(4), 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::ITERATOR_START; setTokenValue(tok->astParent()->tokAt(2), v, settings); } else if (yield == Library::Container::Yield::END_ITERATOR) { v.valueType = ValueFlow::Value::ITERATOR_END; setTokenValue(tok->astParent()->tokAt(2), v, settings); } } } } static std::list getIteratorValues(std::list values, ValueFlow::Value::ValueKind* kind = nullptr) { values.remove_if([&](const ValueFlow::Value& v) { if (kind && v.valueKind != *kind) return true; return !v.isIteratorValue(); }); return values; } static void valueFlowIteratorAfterCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { ValueFlowConditionHandler handler; handler.forward = [&](Token* start, const Token* stop, const Token* vartok, const std::list& values, bool) { return valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings).isModified(); }; handler.parse = [&](const Token *tok) { ValueFlowConditionHandler::Condition cond; ValueFlow::Value true_value; ValueFlow::Value false_value; if (Token::Match(tok, "==|!=")) { if (!tok->astOperand1() || !tok->astOperand2()) return cond; 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; }; handler.afterCondition(tokenlist, symboldatabase, errorLogger, settings); } 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 void valueFlowContainerSize(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger * /*errorLogger*/, const Settings *settings) { // declaration for (const Variable *var : symboldatabase->variableList()) { if (!var || !var->isLocal() || var->isPointer() || var->isReference() || var->isStatic()) continue; if (!var->valueType() || !var->valueType()->container) continue; if (!Token::Match(var->nameToken(), "%name% ;")) continue; if (!astIsContainer(var->nameToken())) continue; if (var->nameToken()->hasKnownValue()) continue; ValueFlow::Value value(0); if (var->valueType()->container->size_templateArgNo >= 0) { if (var->dimensions().size() == 1 && var->dimensions().front().known) value.intvalue = var->dimensions().front().num; else continue; } value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowContainerForward(var->nameToken()->next(), var, value, tokenlist); } // after assignment for (const Scope *functionScope : symboldatabase->functionScopes) { for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) { 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->variable(), value, tokenlist); } } else if (Token::Match(tok, "%var% . %name% (") && tok->valueType() && tok->valueType()->container) { Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2)); if (action == Library::Container::Action::CLEAR) { ValueFlow::Value value(0); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowContainerForward(tok->next(), tok->variable(), value, tokenlist); } else if (action == Library::Container::Action::RESIZE && tok->tokAt(4)->hasKnownIntValue()) { ValueFlow::Value value(tok->tokAt(4)->values().front()); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; value.setKnown(); valueFlowContainerForward(tok->next(), tok->variable(), value, tokenlist); } } } } // conditional conditionSize for (const Scope &scope : symboldatabase->scopeList) { if (scope.type != Scope::ScopeType::eIf) // TODO: while continue; for (const Token *tok = scope.classDef; tok && tok->str() != "{"; tok = tok->next()) { if (!tok->isName() || !tok->valueType() || tok->valueType()->type != ValueType::CONTAINER || !tok->valueType()->container) continue; const Token *conditionToken; MathLib::bigint intval; if (Token::Match(tok, "%name% . %name% (")) { if (tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::SIZE) { const Token *parent = tok->tokAt(3)->astParent(); if (!parent || !parent->isComparisonOp() || !parent->astOperand2()) continue; if (parent->astOperand1()->hasKnownIntValue()) intval = parent->astOperand1()->values().front().intvalue; else if (parent->astOperand2()->hasKnownIntValue()) intval = parent->astOperand2()->values().front().intvalue; else continue; conditionToken = parent; } else if (tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::EMPTY) { conditionToken = tok->tokAt(3); intval = 0; } else { continue; } } else if (tok->valueType()->container->stdStringLike && Token::Match(tok, "%name% ==|!= %str%") && tok->next()->astOperand2() == tok->tokAt(2)) { intval = Token::getStrLength(tok->tokAt(2)); conditionToken = tok->next(); } else { continue; } ValueFlow::Value value(conditionToken, intval); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; // possible value before condition valueFlowContainerReverse(const_cast(scope.classDef), tok->varId(), value, settings); } } } static void valueFlowContainerAfterCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { ValueFlowConditionHandler handler; handler.forward = [&](Token* start, const Token* stop, const Token* vartok, const std::list& values, bool) { // TODO: Forward multiple values if (values.empty()) return false; const Variable* var = vartok->variable(); if (!var) return false; return valueFlowContainerForward(start->next(), stop, var, values.front(), tokenlist).isModified(); }; handler.parse = [&](const Token *tok) { ValueFlowConditionHandler::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 cond; true_value.valueType = ValueFlow::Value::CONTAINER_SIZE; false_value.valueType = ValueFlow::Value::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 cond; const Token *parent = tok->astParent(); while (parent) { if (Token::Match(parent, "%comp%")) return cond; 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 cond; if (!astIsContainer(vartok)) return cond; 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; return cond; } return cond; }; handler.afterCondition(tokenlist, symboldatabase, errorLogger, settings); } static void valueFlowFwdAnalysis(const TokenList *tokenlist, const Settings *settings) { for (const Token *tok = tokenlist->front(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "for (")) tok = tok->linkAt(1); if (tok->str() != "=" || !tok->astOperand1() || !tok->astOperand2()) continue; // Skip variables if (tok->astOperand1()->variable()) continue; if (!tok->scope()->isExecutable()) continue; if (!tok->astOperand2()->hasKnownIntValue()) continue; ValueFlow::Value v(tok->astOperand2()->values().front()); v.errorPath.emplace_back(tok, tok->astOperand1()->expressionString() + " is assigned value " + MathLib::toString(v.intvalue)); const Token *startToken = tok->findExpressionStartEndTokens().second->next(); const Scope *functionScope = tok->scope(); while (functionScope->nestedIn && functionScope->nestedIn->isExecutable()) functionScope = functionScope->nestedIn; const Token *endToken = functionScope->bodyEnd; valueFlowForwardExpression(const_cast(startToken), endToken, tok->astOperand1(), {v}, tokenlist, settings); } } static void valueFlowDynamicBufferSize(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, 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}; valueFlowForwardVariable(const_cast(rhs), functionScope->bodyEnd, tok->next()->variable(), tok->next()->varId(), values, true, false, tokenlist, errorLogger, 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, ErrorLogger *errorLogger, 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, 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; valueFlowForwardVariable(const_cast(functionScope->bodyStart->next()), functionScope->bodyEnd, &arg, arg.declarationId(), argValues, false, false, tokenlist, errorLogger, 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()) valueFlowForwardVariable(const_cast(functionScope->bodyStart->next()), functionScope->bodyEnd, &arg, arg.declarationId(), argValues, false, false, tokenlist, errorLogger, 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) : valueType(INT), bound(Bound::Point), intvalue(val), tokvalue(nullptr), floatValue(0.0), moveKind(MoveKind::NonMovedVariable), varvalue(val), condition(c), varId(0U), safe(false), conditional(false), defaultArg(false), indirect(0), path(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 INT: return MathLib::toString(intvalue); case TOK: return tokvalue->str(); case FLOAT: return MathLib::toString(floatValue); case MOVED: return ""; case UNINIT: return ""; case BUFFER_SIZE: case CONTAINER_SIZE: return "size=" + MathLib::toString(intvalue); case ITERATOR_START: return "start=" + MathLib::toString(intvalue); case ITERATOR_END: return "end=" + MathLib::toString(intvalue); case LIFETIME: return "lifetime=" + tokvalue->str(); } 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 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(); valueFlowNumber(tokenlist); valueFlowString(tokenlist); valueFlowArray(tokenlist); valueFlowUnknownFunctionReturn(tokenlist, settings); valueFlowGlobalConstVar(tokenlist, settings); valueFlowGlobalStaticVar(tokenlist, settings); valueFlowPointerAlias(tokenlist); valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings); valueFlowBitAnd(tokenlist); valueFlowSameExpressions(tokenlist); valueFlowFwdAnalysis(tokenlist, settings); std::size_t values = 0; std::size_t n = 4; while (n > 0 && values < getTotalValues(tokenlist)) { values = getTotalValues(tokenlist); valueFlowPointerAliasDeref(tokenlist); valueFlowArrayBool(tokenlist); valueFlowRightShift(tokenlist, settings); valueFlowOppositeCondition(symboldatabase, settings); valueFlowTerminatingCondition(tokenlist, symboldatabase, errorLogger, settings); valueFlowBeforeCondition(tokenlist, symboldatabase, errorLogger, settings); valueFlowAfterMove(tokenlist, symboldatabase, errorLogger, settings); valueFlowAfterCondition(tokenlist, symboldatabase, errorLogger, settings); valueFlowInferCondition(tokenlist, settings); valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, 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, errorLogger, settings); valueFlowUninit(tokenlist, symboldatabase, errorLogger, settings); if (tokenlist->isCPP()) { valueFlowSmartPointer(tokenlist, errorLogger, settings); valueFlowIterators(tokenlist, settings); valueFlowIteratorAfterCondition(tokenlist, symboldatabase, errorLogger, settings); valueFlowIteratorInfer(tokenlist, settings); valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings); valueFlowContainerAfterCondition(tokenlist, symboldatabase, errorLogger, settings); } valueFlowSafeFunctions(tokenlist, symboldatabase, errorLogger, settings); n--; } valueFlowDynamicBufferSize(tokenlist, symboldatabase, errorLogger, settings); } std::string ValueFlow::eitherTheConditionIsRedundant(const Token *condition) { if (!condition) return "Either the condition is redundant"; if (condition->str() == "case") { std::string expr; for (const Token *tok = condition; tok && tok->str() != ":"; tok = tok->next()) { expr += tok->str(); if (Token::Match(tok, "%name%|%num% %name%|%num%")) expr += ' '; } return "Either the switch case '" + expr + "' is redundant"; } return "Either the condition '" + condition->expressionString() + "' is redundant"; }