/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2018 Cppcheck team. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ /** * @brief This is the ValueFlow component in Cppcheck. * * Each @sa Token in the token list has a list of values. These are * the "possible" values for the Token at runtime. * * In the --debug and --debug-normal output you can see the ValueFlow data. For example: * * int f() * { * int x = 10; * return 4 * x + 2; * } * * The --debug-normal output says: * * ##Value flow * Line 3 * 10 always 10 * Line 4 * 4 always 4 * * always 40 * x always 10 * + always 42 * 2 always 2 * * All value flow analysis is executed in the ValueFlow::setValues() function. The ValueFlow analysis is executed after the tokenizer/ast/symboldatabase/etc.. * The ValueFlow analysis is done in a series of valueFlow* function calls, where each such function call can only use results from previous function calls. * The function calls should be arranged so that valueFlow* that do not require previous ValueFlow information should be first. * * Type of analysis * ================ * * This is "flow sensitive" value flow analysis. We _usually_ track the value for 1 variable at a time. * * How are calculations handled * ============================ * * Here is an example code: * * x = 3 + 4; * * The valueFlowNumber set the values for the "3" and "4" tokens by calling setTokenValue(). * The setTokenValue() handle the calculations automatically. When both "3" and "4" have values, the "+" can be calculated. setTokenValue() recursively calls itself when parents in calculations can be calculated. * * Forward / Reverse flow analysis * =============================== * * In forward value flow analysis we know a value and see what happens when we are stepping the program forward. Like normal execution. * The valueFlowForward is used in this analysis. * * In reverse value flow analysis we know the value of a variable at line X. And try to "execute backwards" to determine possible values before line X. * The valueFlowReverse is used in this analysis. * * */ #include "valueflow.h" #include "astutils.h" #include "errorlogger.h" #include "library.h" #include "mathlib.h" #include "platform.h" #include "settings.h" #include "standards.h" #include "symboldatabase.h" #include "token.h" #include "tokenlist.h" #include "utils.h" #include "path.h" #include #include #include #include #include #include #include #include #include static const int TIMEOUT = 10; // Do not repeat ValueFlow analysis more than 10 seconds namespace { struct ProgramMemory { std::map values; void setValue(unsigned int varid, const ValueFlow::Value &value) { values[varid] = value; } bool getIntValue(unsigned int varid, MathLib::bigint* result) const { const std::map::const_iterator it = values.find(varid); const bool found = it != values.end() && it->second.isIntValue(); if (found) *result = it->second.intvalue; return found; } void setIntValue(unsigned int varid, MathLib::bigint value) { values[varid] = ValueFlow::Value(value); } bool getTokValue(unsigned int varid, const Token** result) const { const std::map::const_iterator it = values.find(varid); const bool found = it != values.end() && it->second.isTokValue(); if (found) *result = it->second.tokvalue; return found; } bool hasValue(unsigned int varid) { return values.find(varid) != values.end(); } void swap(ProgramMemory &pm) { values.swap(pm.values); } void clear() { values.clear(); } bool empty() const { return values.empty(); } }; } static void execute(const Token *expr, ProgramMemory * const programMemory, MathLib::bigint *result, bool *error); 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, ErrorLogger::ErrorMessage::FileLocation(tok, tokenlist)); ErrorLogger::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) { std::list::iterator it; for (it = values.begin(); it != values.end(); ++it) it->changeKnownToPossible(); } /** * Is condition always false when variable has given value? * \param condition top ast token in condition * \param programMemory program memory */ static bool conditionIsFalse(const Token *condition, const ProgramMemory &programMemory) { if (!condition) return false; if (condition->str() == "&&") { return conditionIsFalse(condition->astOperand1(), programMemory) || conditionIsFalse(condition->astOperand2(), programMemory); } ProgramMemory progmem(programMemory); MathLib::bigint result = 0; bool error = false; execute(condition, &progmem, &result, &error); return !error && result == 0; } /** * Is condition always true when variable has given value? * \param condition top ast token in condition * \param programMemory program memory */ static bool conditionIsTrue(const Token *condition, const ProgramMemory &programMemory) { if (!condition) return false; if (condition->str() == "||") { return conditionIsTrue(condition->astOperand1(), programMemory) || conditionIsTrue(condition->astOperand2(), programMemory); } ProgramMemory progmem(programMemory); bool error = false; MathLib::bigint result = 0; execute(condition, &progmem, &result, &error); return !error && result == 1; } /** * Get program memory by looking backwards from given token. */ static ProgramMemory getProgramMemory(const Token *tok, unsigned int varid, const ValueFlow::Value &value) { ProgramMemory programMemory; programMemory.setValue(varid, value); if (value.varId) programMemory.setIntValue(value.varId, value.varvalue); const ProgramMemory programMemory1(programMemory); int indentlevel = 0; for (const Token *tok2 = tok; tok2; tok2 = tok2->previous()) { if (Token::Match(tok2, "[;{}] %varid% = %var% ;", varid)) { const Token *vartok = tok2->tokAt(3); programMemory.setValue(vartok->varId(), value); } else if (Token::Match(tok2, "[;{}] %var% =") || Token::Match(tok2, "[;{}] const| %type% %var% (")) { const Token *vartok = tok2->next(); while (vartok->next()->isName()) vartok = vartok->next(); if (!programMemory.hasValue(vartok->varId())) { MathLib::bigint result = 0; bool error = false; execute(vartok->next()->astOperand2(), &programMemory, &result, &error); if (!error) programMemory.setIntValue(vartok->varId(), result); } } if (tok2->str() == "{") { if (indentlevel <= 0) break; --indentlevel; } if (tok2->str() == "}") { const Token *cond = tok2->link(); cond = Token::simpleMatch(cond->previous(), ") {") ? cond->linkAt(-1) : nullptr; if (cond && conditionIsFalse(cond->astOperand2(), programMemory1)) tok2 = cond->previous(); else if (cond && conditionIsTrue(cond->astOperand2(), programMemory1)) { ++indentlevel; continue; } else break; } } return programMemory; } /** * 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; // 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())) { // 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; 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, unsigned 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.isInconclusive() || value2.isInconclusive()) result->setInconclusive(); else result->setPossible(); 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; } /** 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; // Don't set parent for uninitialized values if (value.isUninitValue()) return; Token *parent = const_cast(tok->astParent()); if (!parent) return; if (value.isContainerSizeValue()) { // .empty, .size, +"abc", +'a' if (parent->str() == "+") { for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) { for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) { 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(const_cast(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(const_cast(parent->astParent()), v, settings); } } return; } if (value.isLifetimeValue()) { if (value.lifetimeKind == ValueFlow::Value::Iterator && astIsIterator(parent)) { setTokenValue(parent,value,settings); } else if (astIsPointer(tok) && astIsPointer(parent) && (parent->isArithmeticalOp() || Token::Match(parent, "( %type%"))) { setTokenValue(parent,value,settings); } return; } // cast.. if (parent->str() == "(" && !parent->astOperand2() && Token::Match(parent,"( %name%")) { const ValueType &valueType = ValueType::parseDecl(parent->next(), settings); setTokenValueCast(parent, valueType, value, settings); } else if (parent->str() == "(" && parent->astOperand2() && Token::Match(parent->astOperand1(), "const_cast|dynamic_cast|reinterpret_cast|static_cast <")) { const ValueType &valueType = ValueType::parseDecl(parent->astOperand1()->tokAt(2), 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? unsigned 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); } } // Calculations.. else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp) || (parent->tokType() == Token::eLogicalOp)) && parent->astOperand1() && parent->astOperand2()) { // 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 (!value1.isIntValue() && !value1.isFloatValue() && !value1.isTokValue()) continue; if (value1.isTokValue() && (!parent->isComparisonOp() || value1.tokvalue->tokType() != Token::eString)) continue; for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) { if (!value2.isIntValue() && !value2.isFloatValue() && !value2.isTokValue()) continue; if (value2.isTokValue() && (!parent->isComparisonOp() || value2.tokvalue->tokType() != Token::eString || value1.isTokValue())) 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 { 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 { 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; unsigned 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()) v.intvalue = -v.intvalue; else v.floatValue = -v.floatValue; 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); } } } } } } } 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 unsigned int getSizeOfType(const Token *typeTok, const Settings *settings) { const std::string &typeStr = typeTok->str(); if (typeStr == "char") return 1; else if (typeStr == "short") return settings->sizeof_short; else if (typeStr == "int") return settings->sizeof_int; else if (typeStr == "long") return typeTok->isLong() ? settings->sizeof_long_long : settings->sizeof_long; else if (typeStr == "wchar_t") return settings->sizeof_wchar_t; else return 0; } // Handle various constants.. static Token * valueFlowSetConstantValue(const 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(const_cast(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(const_cast(tok), value, settings); } else if (tok->enumerator() && tok->enumerator()->value_known) { ValueFlow::Value value(tok->enumerator()->value); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(const_cast(tok), value, settings); } else if (tok->str() == "NULL" || (cpp && tok->str() == "nullptr")) { ValueFlow::Value value(0); if (!tok->isTemplateArg()) value.setKnown(); setTokenValue(const_cast(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 (tok2->enumerator() && tok2->enumerator()->scope) { long long size = settings->sizeof_int; const Token * type = tok2->enumerator()->scope->enumType; if (type) { size = getSizeOfType(type, settings); } ValueFlow::Value value(size); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok), value, settings); setTokenValue(const_cast(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(const_cast(tok), value, settings); setTokenValue(const_cast(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 unsigned 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(const_cast(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->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(const_cast(tok), value, settings); setTokenValue(const_cast(tok->next()), value, settings); } } } else if (!tok2->type()) { const ValueType &vt = ValueType::parseDecl(tok2,settings); if (vt.pointer) { ValueFlow::Value value(settings->sizeof_pointer); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::CHAR) { ValueFlow::Value value(1); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::SHORT) { ValueFlow::Value value(settings->sizeof_short); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::INT) { ValueFlow::Value value(settings->sizeof_int); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::LONG) { ValueFlow::Value value(settings->sizeof_long); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::LONGLONG) { ValueFlow::Value value(settings->sizeof_long_long); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::FLOAT) { ValueFlow::Value value(settings->sizeof_float); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(tok->next()), value, settings); } else if (vt.type == ValueType::Type::DOUBLE) { ValueFlow::Value value(settings->sizeof_double); if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified) value.setKnown(); setTokenValue(const_cast(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 if (tok->variable() && tok->variable()->isArray() && !tok->variable()->isArgument() && !tok->variable()->isStlType()) { ValueFlow::Value value{1}; value.setKnown(); setTokenValue(tok, value, tokenlist->getSettings()); } 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 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 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 (astIsFloat(tok->astOperand1(), true) || astIsFloat(tok->astOperand2(), true)) 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, const Settings *settings) { const bool cpp = symboldatabase->isCPP(); typedef std::pair Condition; for (const Scope * scope : symboldatabase->functionScopes) { std::vector conds; for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) { 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); } 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) { 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; if ((1 << 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; const Token *ifOpenBraceTok = tok2->tokAt(4); const 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(const_cast(cond2), value, settings); } tok2 = ifOpenBraceTok->link(); } } } 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 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 unsigned 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)) { break; } if (tok2->varId() == varid) { // bailout: assignment if (Token::Match(tok2->previous(), "!!* %name% =")) { 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, settings, &inconclusive)) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction"); 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 *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(); } } 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 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; } unsigned int varid = vartok->varId(); const Variable * const var = vartok->variable(); if (varid == 0U || !var) 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->typeStartToken()->isUnsigned()) continue; } ValueFlow::Value val(tok, num); val.varId = varid; ValueFlow::Value val2; if (num==1U && Token::Match(tok,"<=|>=")) { if (var->typeStartToken()->isUnsigned()) { val2 = ValueFlow::Value(tok,0); val2.varId = varid; } } valueFlowReverse(tokenlist, tok, vartok, val, val2, errorLogger, settings); } } } static void removeValues(std::list &values, const std::list &valuesToRemove) { for (std::list::iterator it = values.begin(); it != values.end();) { bool found = false; for (const ValueFlow::Value &v2 : valuesToRemove) { if (it->intvalue == v2.intvalue) { found = true; break; } } if (found) values.erase(it++); else ++it; } } static void valueFlowAST(Token *tok, unsigned int varid, const ValueFlow::Value &value, const Settings *settings) { if (!tok) return; if (tok->varId() == varid) setTokenValue(tok, value, settings); valueFlowAST(const_cast(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(); bool nonzero = false; for (const ValueFlow::Value &v : values) { if (v.intvalue != 0) { nonzero = true; break; } } if (!nonzero) return; ProgramMemory pm; pm.setValue(varid,value); if (conditionIsTrue(tok->astOperand1(), pm)) return; } valueFlowAST(const_cast(tok->astOperand2()), varid, value, settings); } /** if known variable is changed in loop body, change it to a possible value */ static void handleKnownValuesInLoop(const Token *startToken, const Token *endToken, std::list *values, unsigned int varid, bool globalvar, const Settings *settings) { bool isChanged = false; for (std::list::iterator it = values->begin(); it != values->end(); ++it) { if (it->isKnown()) { if (!isChanged) { if (!isVariableChanged(startToken, endToken, varid, globalvar, settings, true)) break; isChanged = true; } it->setPossible(); } } } 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 == "/=") { if (rhsValue.intvalue == 0) return false; else lhsValue.intvalue /= rhsValue.intvalue; } else if (assign == "%=") { if (rhsValue.intvalue == 0) return false; else 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 return false; } else if (lhsValue.isFloatValue()) { 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; } static bool valueFlowForward(Token * const startToken, const Token * const endToken, const Variable * const var, const unsigned int varid, std::list values, const bool constValue, const bool subFunction, TokenList * const tokenlist, ErrorLogger * const errorLogger, const Settings * const settings) { int indentlevel = 0; unsigned int number_of_if = 0; int varusagelevel = -1; bool returnStatement = false; // current statement is a return, stop analysis at the ";" bool read = false; // is variable value read? if (values.empty()) return true; for (Token *tok2 = startToken; tok2 && tok2 != endToken; tok2 = tok2->next()) { if (indentlevel >= 0 && tok2->str() == "{") ++indentlevel; else if (indentlevel >= 0 && tok2->str() == "}") { --indentlevel; if (indentlevel <= 0 && isReturnScope(tok2) && Token::Match(tok2->link()->previous(), "else|) {")) { const Token *condition = tok2->link(); const bool iselse = Token::simpleMatch(condition->tokAt(-2), "} else {"); if (iselse) condition = condition->linkAt(-2); if (condition && Token::simpleMatch(condition->previous(), ") {")) condition = condition->linkAt(-1)->astOperand2(); else condition = nullptr; if (!condition) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, bailing out since it's unknown if conditional return is executed"); return false; } bool bailoutflag = false; const Token * const start1 = iselse ? tok2->link()->linkAt(-2) : nullptr; for (std::list::iterator it = values.begin(); it != values.end();) { if (!iselse && conditionIsTrue(condition, getProgramMemory(condition->astParent(), varid, *it))) { bailoutflag = true; break; } if (iselse && conditionIsFalse(condition, getProgramMemory(condition->astParent(), varid, *it))) { bailoutflag = true; break; } if (iselse && it->isPossible() && isVariableChanged(start1, start1->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) values.erase(it++); else ++it; } if (bailoutflag) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, conditional return is assumed to be executed"); return false; } if (values.empty()) return true; } else if (indentlevel <= 0 && Token::simpleMatch(tok2->link()->previous(), "else {") && !isReturnScope(tok2->link()->tokAt(-2)) && isVariableChanged(tok2->link(), tok2, varid, var->isGlobal(), settings, tokenlist->isCPP())) { changeKnownToPossible(values); } } // skip lambda functions // TODO: handle lambda functions if (tok2->str() == "[" && findLambdaEndToken(tok2)) { Token *lambdaEndToken = const_cast(findLambdaEndToken(tok2)); if (isVariableChanged(lambdaEndToken->link(), lambdaEndToken, varid, var->isGlobal(), settings, tokenlist->isCPP())) return false; // Dont skip lambdas for lifetime values if (!std::all_of(values.begin(), values.end(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) { tok2 = lambdaEndToken; continue; } } if (Token::Match(tok2, "[;{}] %name% :") || tok2->str() == "case") { changeKnownToPossible(values); tok2 = tok2->tokAt(2); continue; } else if ((var->isGlobal() || tok2->str() == "asm") && Token::Match(tok2, "%name% (") && Token::Match(tok2->linkAt(1), ") !!{")) { return false; } // Skip sizeof etc else if (Token::Match(tok2, "sizeof|typeof|typeid (")) tok2 = tok2->linkAt(1); else if (Token::simpleMatch(tok2, "else {")) { // Should scope be skipped because variable value is checked? bool skipelse = false; const Token *condition = tok2->linkAt(-1); condition = condition ? condition->linkAt(-1) : nullptr; condition = condition ? condition->astOperand2() : nullptr; for (const ValueFlow::Value &v : values) { if (conditionIsTrue(condition, getProgramMemory(tok2, varid, v))) { skipelse = true; break; } } if (skipelse) { tok2 = tok2->linkAt(1); continue; } } else if (Token::simpleMatch(tok2, "do {")) { const Token *start = tok2->next(); const Token *end = start->link(); if (Token::simpleMatch(end, "} while (")) end = end->linkAt(2); if (isVariableChanged(start, end, varid, var->isGlobal(), settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, assignment in do-while"); return false; } handleKnownValuesInLoop(start, end, &values, varid, var->isGlobal(), settings); } // conditional block of code that assigns variable.. else if (!tok2->varId() && Token::Match(tok2, "%name% (") && Token::simpleMatch(tok2->linkAt(1), ") {")) { // is variable changed in condition? if (isVariableChanged(tok2->next(), tok2->next()->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, assignment in condition"); return false; } // if known variable is changed in loop body, change it to a possible value.. if (Token::Match(tok2, "for|while")) handleKnownValuesInLoop(tok2, tok2->linkAt(1)->linkAt(1), &values, varid, var->isGlobal(), settings); // Set values in condition for (Token* tok3 = tok2->tokAt(2); tok3 != tok2->next()->link(); tok3 = tok3->next()) { if (tok3->varId() == varid) { for (const ValueFlow::Value &v : values) setTokenValue(tok3, v, settings); } else if (Token::Match(tok3, "%oror%|&&|?|;")) { break; } } const Token * const condTok = tok2->next()->astOperand2(); const bool condAlwaysTrue = (condTok && condTok->hasKnownIntValue() && condTok->values().front().intvalue != 0); const bool condAlwaysFalse = (condTok && condTok->hasKnownIntValue() && condTok->values().front().intvalue == 0); // Should scope be skipped because variable value is checked? std::list truevalues; std::list falsevalues; for (const ValueFlow::Value &v : values) { if (condAlwaysTrue) { truevalues.push_back(v); continue; } if (condAlwaysFalse) { falsevalues.push_back(v); continue; } const ProgramMemory &programMemory = getProgramMemory(tok2, varid, v); if (subFunction && conditionIsTrue(condTok, programMemory)) truevalues.push_back(v); else if (!subFunction && !conditionIsFalse(condTok, programMemory)) truevalues.push_back(v); if (condAlwaysFalse) falsevalues.push_back(v); else if (conditionIsFalse(condTok, programMemory)) falsevalues.push_back(v); else if (!subFunction && !conditionIsTrue(condTok, programMemory)) falsevalues.push_back(v); } if (truevalues.size() != values.size() || condAlwaysTrue) { // '{' const Token * const startToken1 = tok2->linkAt(1)->next(); bool vfresult = valueFlowForward(startToken1->next(), startToken1->link(), var, varid, truevalues, constValue, subFunction, tokenlist, errorLogger, settings); if (!condAlwaysFalse && isVariableChanged(startToken1, startToken1->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) { removeValues(values, truevalues); changeKnownToPossible(values); } // goto '}' tok2 = startToken1->link(); if (isReturnScope(tok2) || !vfresult) { if (condAlwaysTrue) return false; removeValues(values, truevalues); } if (Token::simpleMatch(tok2, "} else {")) { const Token * const startTokenElse = tok2->tokAt(2); vfresult = valueFlowForward(startTokenElse->next(), startTokenElse->link(), var, varid, falsevalues, constValue, subFunction, tokenlist, errorLogger, settings); if (!condAlwaysTrue && isVariableChanged(startTokenElse, startTokenElse->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) { removeValues(values, falsevalues); changeKnownToPossible(values); } // goto '}' tok2 = startTokenElse->link(); if (isReturnScope(tok2) || !vfresult) { if (condAlwaysFalse) return false; removeValues(values, falsevalues); } } continue; } Token * const start = tok2->linkAt(1)->next(); Token * const end = start->link(); const bool varusage = (indentlevel >= 0 && constValue && number_of_if == 0U) ? isVariableChanged(start,end,varid,var->isGlobal(),settings, tokenlist->isCPP()) : (nullptr != Token::findmatch(start, "%varid%", end, varid)); if (!read) { read = bool(nullptr != Token::findmatch(tok2, "%varid% !!=", end, varid)); } if (varusage) { varusagelevel = indentlevel; if (indentlevel < 0 && tok2->str() == "switch") return false; // TODO: don't check noreturn scopes if (read && (number_of_if > 0U || Token::findmatch(tok2, "%varid%", start, varid))) { // Set values in condition const Token * const condend = tok2->linkAt(1); for (Token *condtok = tok2; condtok != condend; condtok = condtok->next()) { if (condtok->varId() == varid) { for (const ValueFlow::Value &v : values) setTokenValue(condtok, v, settings); } if (Token::Match(condtok, "%oror%|&&|?|;")) break; } if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " is assigned in conditional code"); return false; } if (var->isStatic()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " bailout when conditional code that contains var is seen"); return false; } // Forward known values in the else branch if (Token::simpleMatch(end, "} else {")) { std::list knownValues; std::copy_if(values.begin(), values.end(), std::back_inserter(knownValues), std::mem_fn(&ValueFlow::Value::isKnown)); valueFlowForward(end->tokAt(2), end->linkAt(2), var, varid, knownValues, constValue, subFunction, tokenlist, errorLogger, settings); } // Remove conditional values std::list::iterator it; for (it = values.begin(); it != values.end();) { if (it->condition || it->conditional) values.erase(it++); else { it->changeKnownToPossible(); ++it; } } } // stop after conditional return scopes that are executed if (isReturnScope(end)) { std::list::iterator it; for (it = values.begin(); it != values.end();) { if (conditionIsTrue(tok2->next()->astOperand2(), getProgramMemory(tok2, varid, *it))) values.erase(it++); else ++it; } if (values.empty()) return false; } // noreturn scopes.. if ((number_of_if > 0 || Token::findmatch(tok2, "%varid%", start, varid)) && (isEscapeScope(start, tokenlist) || (Token::simpleMatch(end,"} else {") && isEscapeScope(end->tokAt(2), tokenlist)))) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + ". noreturn conditional scope."); return false; } if (isVariableChanged(start, end, varid, var->isGlobal(), settings, tokenlist->isCPP())) { if ((!read || number_of_if == 0) && Token::simpleMatch(tok2, "if (") && !(Token::simpleMatch(end, "} else {") && isEscapeScope(end->tokAt(2), tokenlist))) { ++number_of_if; tok2 = end; } else { // loop that conditionally set variable and then break => either loop condition is // redundant or the variable can be unchanged after the loop. bool loopCondition = false; if (Token::simpleMatch(tok2, "while (") && Token::Match(tok2->next()->astOperand2(), "%op%")) loopCondition = true; else if (Token::simpleMatch(tok2, "for (") && Token::simpleMatch(tok2->next()->astOperand2(), ";") && Token::simpleMatch(tok2->next()->astOperand2()->astOperand2(), ";") && Token::Match(tok2->next()->astOperand2()->astOperand2()->astOperand1(), "%op%")) loopCondition = true; bool bail = true; if (loopCondition) { const Token *tok3 = Token::findmatch(start, "%varid%", end, varid); if (Token::Match(tok3, "%varid% =", varid) && tok3->scope()->bodyEnd && Token::Match(tok3->scope()->bodyEnd->tokAt(-3), "[;}] break ;") && !Token::findmatch(tok3->next(), "%varid%", end, varid)) { bail = false; tok2 = end; } } if (bail) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " is assigned in conditional code"); return false; } } } } else if (Token::Match(tok2, "assert|ASSERT (") && Token::simpleMatch(tok2->linkAt(1), ") ;")) { const Token * const arg = tok2->next()->astOperand2(); if (arg != nullptr && arg->str() != ",") { // Should scope be skipped because variable value is checked? for (std::list::iterator it = values.begin(); it != values.end();) { if (conditionIsFalse(arg, getProgramMemory(tok2, varid, *it))) values.erase(it++); else ++it; } } } else if (tok2->str() == "}" && indentlevel == varusagelevel) { ++number_of_if; // Set "conditional" flag for all values std::list::iterator it; for (it = values.begin(); it != values.end(); ++it) { it->conditional = true; it->changeKnownToPossible(); } if (Token::simpleMatch(tok2,"} else {")) tok2 = tok2->linkAt(2); } else if (Token::Match(tok2, "break|continue|goto")) { const Scope *scope = tok2->scope(); if (indentlevel > 0) { const Token *tok3 = tok2->tokAt(2); int indentlevel2 = indentlevel; while (indentlevel2 > 0 && tok3->str() == "}" && Token::Match(tok3->link()->previous(), "!!)")) { indentlevel2--; tok3 = tok3->next(); if (tok3 && tok3->str() == ";") tok3 = tok3->next(); } if (indentlevel2 > 0) continue; scope = tok3->scope(); indentlevel = 0; } if (tok2->str() == "break") { if (scope && scope->type == Scope::eSwitch) { tok2 = const_cast(scope->bodyEnd); if (tok2 == endToken) break; --indentlevel; changeKnownToPossible(values); continue; } } if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + ". noreturn conditional scope."); return false; } else if (indentlevel <= 0 && Token::Match(tok2, "return|throw")) returnStatement = true; else if (returnStatement && tok2->str() == ";") return false; // If a ? is seen and it's known that the condition is true/false.. else if (tok2->str() == "?") { const Token *condition = tok2->astOperand1(); const Token *op2 = tok2->astOperand2(); if (!condition || !op2) // Ticket #6713 continue; if (condition->hasKnownIntValue()) { const ValueFlow::Value &condValue = condition->values().front(); const Token *expr = (condValue.intvalue != 0) ? op2->astOperand1() : op2->astOperand2(); for (const ValueFlow::Value &v : values) valueFlowAST(const_cast(expr), varid, v, settings); if (isVariableChangedByFunctionCall(expr, varid, settings, nullptr)) changeKnownToPossible(values); } else { for (const ValueFlow::Value &v : values) { const ProgramMemory programMemory(getProgramMemory(tok2, varid, v)); if (conditionIsTrue(condition, programMemory)) valueFlowAST(const_cast(op2->astOperand1()), varid, v, settings); else if (conditionIsFalse(condition, programMemory)) valueFlowAST(const_cast(op2->astOperand2()), varid, v, settings); else valueFlowAST(const_cast(op2), varid, v, settings); } if (isVariableChangedByFunctionCall(op2, varid, settings, nullptr)) changeKnownToPossible(values); } // Skip conditional expressions.. const Token * const questionToken = tok2; while (tok2->astOperand1() || tok2->astOperand2()) { if (tok2->astOperand2()) tok2 = const_cast(tok2->astOperand2()); else if (tok2->isUnaryPreOp()) tok2 = const_cast(tok2->astOperand1()); else break; } tok2 = tok2->next(); if (isVariableChanged(questionToken, questionToken->astOperand2(), varid, false, settings, tokenlist->isCPP()) && isVariableChanged(questionToken->astOperand2(), tok2, varid, false, settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, assignment in condition"); return false; } } else if (tok2->varId() == varid) { // compound assignment, known value in rhs if (Token::Match(tok2->previous(), "!!* %name% %assign%") && tok2->next()->str() != "=" && tok2->next()->astOperand2() && tok2->next()->astOperand2()->hasKnownIntValue()) { const ValueFlow::Value &rhsValue = tok2->next()->astOperand2()->values().front(); const std::string &assign = tok2->next()->str(); std::list::iterator it; // Erase values that are not int values.. for (it = values.begin(); it != values.end();) { if (!evalAssignment(*it, assign, rhsValue)) { it = values.erase(it); } else { const std::string info("Compound assignment '" + assign + "', assigned value is " + it->infoString()); it->errorPath.emplace_back(tok2, info); ++it; } } if (values.empty()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "compound assignment of " + tok2->str()); return false; } } // bailout: assignment else if (Token::Match(tok2->previous(), "!!* %name% %assign%")) { // simplify rhs std::stack rhs; rhs.push(const_cast(tok2->next()->astOperand2())); while (!rhs.empty()) { Token *rtok = rhs.top(); rhs.pop(); if (!rtok) continue; if (rtok->str() == "(" && Token::Match(rtok->astOperand1(), "sizeof|typeof|typeid")) continue; if (Token::Match(rtok, "++|--|?|:|;|,")) continue; if (rtok->varId() == varid) { for (const ValueFlow::Value &v : values) setTokenValue(rtok, v, settings); } rhs.push(const_cast(rtok->astOperand1())); rhs.push(const_cast(rtok->astOperand2())); } if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str()); return false; } // bailout: possible assignment using >> if (isLikelyStreamRead(tokenlist->isCPP(), tok2->previous())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "Possible assignment of " + tok2->str() + " using " + tok2->strAt(-1)); return false; } // 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"); const Token *astTop = parent->astTop(); if (Token::simpleMatch(astTop->astOperand1(), "for (")) tok2 = const_cast(astTop->link()); // bailout if address of var is taken.. if (tok2->astParent() && tok2->astParent()->isUnaryOp("&")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "Taking address of " + tok2->str()); return false; } continue; } { // Is variable usage protected by && || ?: const Token *tok3 = tok2; const Token *parent = tok3->astParent(); while (parent && !Token::Match(parent, "%oror%|&&|:")) { tok3 = parent; parent = parent->astParent(); } const bool conditional = parent && (parent->str() == ":" || parent->astOperand2() == tok3); for (const ValueFlow::Value &v : values) { if (!conditional || !v.conditional) setTokenValue(tok2, v, settings); } } // increment/decrement if (Token::Match(tok2->previous(), "++|-- %name%") || Token::Match(tok2, "%name% ++|--")) { std::list::iterator it; // Erase values that are not int values.. for (it = values.begin(); it != values.end();) { if (!it->isIntValue()) it = values.erase(it); else ++it; } if (values.empty()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "increment/decrement of " + tok2->str()); return false; } const bool pre = Token::Match(tok2->previous(), "++|--"); Token * const op = pre ? tok2->previous() : tok2->next(); const bool inc = (op->str() == "++"); // Perform increment/decrement.. for (it = values.begin(); it != values.end(); ++it) { if (!pre) setTokenValue(op, *it, settings); it->intvalue += (inc ? 1 : -1); if (pre) setTokenValue(op, *it, settings); const std::string info(tok2->str() + " is " + std::string(inc ? "incremented" : "decremented") + "', new value is " + it->infoString()); it->errorPath.emplace_back(tok2, info); } } // bailout if address of var is taken.. if (tok2->astParent() && tok2->astParent()->isUnaryOp("&")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "Taking address of " + tok2->str()); return false; } // bailout if reference is created.. if (tok2->astParent() && Token::Match(tok2->astParent()->tokAt(-2), "& %name% =")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "Reference of " + tok2->str()); return false; } // assigned by subfunction? bool inconclusive = false; if (isVariableChangedByFunctionCall(tok2, settings, &inconclusive)) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction"); return false; } if (inconclusive) { for (ValueFlow::Value &v : values) v.setInconclusive(); } if (tok2->strAt(1) == "." && tok2->next()->originalName() != "->") { if (settings->inconclusive) { for (ValueFlow::Value &v : values) v.setInconclusive(); } else { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by member function"); return false; } } } // Lambda function if (Token::simpleMatch(tok2, "= [") && Token::simpleMatch(tok2->linkAt(1), "] (") && Token::simpleMatch(tok2->linkAt(1)->linkAt(1), ") {")) { const Token *bodyStart = tok2->linkAt(1)->linkAt(1)->next(); if (isVariableChanged(bodyStart, bodyStart->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok2, "valueFlowForward, " + var->name() + " is changed in lambda function"); return false; } } } return true; } static const Variable *getLifetimeVariable(const Token *tok, ErrorPath &errorPath) { const Variable *var = tok->variable(); if (!var) return nullptr; if (var->isReference() || var->isRValueReference()) { for (const ValueFlow::Value &v : tok->values()) { if (!v.isLifetimeValue()) continue; if (v.tokvalue == tok) continue; errorPath.insert(errorPath.end(), v.errorPath.begin(), v.errorPath.end()); const Variable *var2 = getLifetimeVariable(v.tokvalue, errorPath); if (var2) return var2; } return nullptr; } return var; } static bool isNotLifetimeValue(const ValueFlow::Value& val) { return !val.isLifetimeValue(); } static void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings); static void valueFlowForwardLifetime(Token * tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) { const Token *parent = tok->astParent(); while (parent && (parent->isArithmeticalOp() || parent->str() == ",")) parent = parent->astParent(); if (!parent) return; // Assignment if (parent->str() == "=" && !parent->astParent()) { // Lhs should be a variable if (!parent->astOperand1() || !parent->astOperand1()->varId()) return; const Variable *var = parent->astOperand1()->variable(); if (!var || (!var->isLocal() && !var->isGlobal() && !var->isArgument())) return; const Token *const endOfVarScope = var->typeStartToken()->scope()->bodyEnd; // Rhs values.. if (!parent->astOperand2() || parent->astOperand2()->values().empty()) return; if (astIsPointer(parent->astOperand2()) && !var->isPointer() && !(var->valueType() && var->valueType()->isIntegral())) return; std::list values = parent->astOperand2()->values(); // Static variable initialisation? if (var->isStatic() && var->nameToken() == parent->astOperand1()) changeKnownToPossible(values); // Skip RHS const Token *nextExpression = nextAfterAstRightmostLeaf(parent); // Only forward lifetime values values.remove_if(&isNotLifetimeValue); valueFlowForward(const_cast(nextExpression), endOfVarScope, var, var->declarationId(), values, false, false, tokenlist, errorLogger, settings); // Function call } else if (Token::Match(parent->previous(), "%name% (")) { valueFlowLifetimeFunction(const_cast(parent->previous()), tokenlist, errorLogger, settings); // Variable } else if (tok->variable()) { const Variable *var = tok->variable(); if (!var->typeStartToken() && !var->typeStartToken()->scope()) return; const Token *endOfVarScope = var->typeStartToken()->scope()->bodyEnd; std::list values = tok->values(); const Token *nextExpression = nextAfterAstRightmostLeaf(parent); // Only forward lifetime values values.remove_if(&isNotLifetimeValue); valueFlowForward(const_cast(nextExpression), endOfVarScope, var, var->declarationId(), values, false, false, tokenlist, errorLogger, settings); } } struct LifetimeStore { const Token *argtok; std::string message; ValueFlow::Value::LifetimeKind type; template void byRef(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const { ErrorPath errorPath; const Variable *var = getLifetimeVariable(argtok, errorPath); if (!var) return; if (!pred(var)) return; errorPath.emplace_back(argtok, message); ValueFlow::Value value; value.valueType = ValueFlow::Value::LIFETIME; value.tokvalue = var->nameToken(); value.errorPath = errorPath; value.lifetimeKind = type; // Dont 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 Variable *) { return true; }); } template void byVal(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const { for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok3 = v.tokvalue; ErrorPath errorPath = v.errorPath; const Variable *var = getLifetimeVariable(tok3, errorPath); if (!var) continue; if (!pred(var)) return; errorPath.emplace_back(argtok, message); ValueFlow::Value value; value.valueType = ValueFlow::Value::LIFETIME; value.tokvalue = var->nameToken(); value.errorPath = errorPath; value.lifetimeKind = type; // Dont 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 Variable *) { return true; }); } template void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const { for (const ValueFlow::Value &v : argtok->values()) { if (!v.isLifetimeValue()) continue; const Token *tok2 = v.tokvalue; ErrorPath errorPath = v.errorPath; const Variable *var = getLifetimeVariable(tok2, errorPath); if (!var) continue; for (const Token *tok3 = tok; tok3 && tok3 != var->declEndToken(); tok3 = tok3->previous()) { if (tok3->varId() == var->declarationId()) { LifetimeStore{tok3, message, type} .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 Variable *) { return true; }); } }; static const Token *endTemplateArgument(const Token *tok) { for (; tok; tok = tok->next()) { if (Token::Match(tok, ">|,")) return tok; else if (tok->link() && Token::Match(tok, "(|{|[|<")) tok = tok->link(); else if (Token::simpleMatch(tok, ";")) return nullptr; } return nullptr; } static void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) { if (!Token::Match(tok, "%name% (")) return; 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::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")) { for (const Token *argtok : getArguments(tok)) { LifetimeStore{argtok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::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))) { const Token *containerTypeTok = tok->tokAt(-2)->valueType()->containerTypeToken; const Token *endTypeTok = endTemplateArgument(containerTypeTok); const bool isPointer = endTypeTok && Token::simpleMatch(endTypeTok->previous(), "*"); Token *vartok = tok->tokAt(-2); std::vector args = getArguments(tok); std::size_t n = args.size(); if (n > 1 && astCanonicalType(args[n - 2]) == astCanonicalType(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::Object} .byDerefCopy( vartok, tokenlist, errorLogger, settings); } else if (!args.empty() && astIsPointer(args.back()) == isPointer) { LifetimeStore{args.back(), "Added to container '" + vartok->str() + "'.", ValueFlow::Value::Object} .byVal( vartok, tokenlist, errorLogger, settings); } } } struct Lambda { explicit Lambda(const Token * tok) : capture(nullptr), arguments(nullptr), returnTok(nullptr), bodyTok(nullptr) { 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; } } const Token * capture; const Token * arguments; const Token * returnTok; const Token * bodyTok; bool isLambda() const { return capture && bodyTok; } }; static bool isDecayedPointer(const Token *tok, const Settings *settings) { if (!tok) return false; if (astIsPointer(tok->astParent()) && !Token::simpleMatch(tok->astParent(), "return")) return true; if (!Token::simpleMatch(tok->astParent(), "return")) return false; if (!tok->scope()) return false; if (!tok->scope()->function) return false; if (!tok->scope()->function->retDef) return false; // TODO: Add valuetypes to return types of functions ValueType vt = ValueType::parseDecl(tok->scope()->function->retDef, settings); if (vt.pointer > 0) return true; return false; } static void valueFlowLifetime(TokenList *tokenlist, SymbolDatabase*, ErrorLogger *errorLogger, const Settings *settings) { for (Token *tok = tokenlist->front(); tok; tok = tok->next()) { Lambda lam(tok); // Lamdas if (lam.isLambda()) { const Scope * bodyScope = lam.bodyTok->scope(); std::set scopes; auto isCapturingVariable = [&](const Variable *var) { 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); return true; }; // TODO: Handle explicit capture bool captureByRef = Token::Match(lam.capture, "[ & ]"); bool captureByValue = Token::Match(lam.capture, "[ = ]"); for (const Token * tok2 = lam.bodyTok; tok2 != lam.bodyTok->link(); tok2 = tok2->next()) { ErrorPath errorPath; if (captureByRef) { LifetimeStore{tok2, "Lambda captures variable by reference here.", ValueFlow::Value::Lambda} .byRef( tok, tokenlist, errorLogger, settings, isCapturingVariable); } else if (captureByValue) { LifetimeStore{tok2, "Lambda captures variable by value here.", ValueFlow::Value::Lambda} .byVal( tok, tokenlist, errorLogger, settings, isCapturingVariable); } } } // address of else if (tok->isUnaryOp("&")) { ErrorPath errorPath; // 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) continue; const Variable * var = getLifetimeVariable(vartok, errorPath); if (!var) continue; if (var->isPointer() && Token::Match(vartok->astParent(), "[|*")) continue; errorPath.emplace_back(tok, "Address of variable taken here."); ValueFlow::Value value; value.valueType = ValueFlow::Value::LIFETIME; value.tokvalue = var->nameToken(); value.errorPath = errorPath; setTokenValue(tok, value, tokenlist->getSettings()); valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings); } // container lifetimes else if (tok->variable() && Token::Match(tok, "%var% . begin|cbegin|rbegin|crbegin|end|cend|rend|crend|data|c_str (")) { ErrorPath errorPath; const Library::Container * container = settings->library.detectContainer(tok->variable()->typeStartToken()); if (!container) continue; const Variable * var = tok->variable(); bool isIterator = !Token::Match(tok->tokAt(2), "data|c_str"); if (isIterator) errorPath.emplace_back(tok, "Iterator to container is created here."); else errorPath.emplace_back(tok, "Pointer to container is created here."); ValueFlow::Value value; value.valueType = ValueFlow::Value::LIFETIME; value.tokvalue = var->nameToken(); value.errorPath = errorPath; value.lifetimeKind = isIterator ? ValueFlow::Value::Iterator : ValueFlow::Value::Object; setTokenValue(tok->tokAt(3), value, tokenlist->getSettings()); valueFlowForwardLifetime(tok->tokAt(3), 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, settings)) { errorPath.emplace_back(tok, "Array decayed to pointer here."); ValueFlow::Value value; value.valueType = ValueFlow::Value::LIFETIME; value.tokvalue = var->nameToken(); value.errorPath = errorPath; setTokenValue(tok, value, tokenlist->getSettings()); 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::NonMovedVariable; Token * variableToken = nullptr; if (Token::Match(tok, "std :: move ( %var% )")) { variableToken = tok->tokAt(4); kind = ValueFlow::Value::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::ForwardedVariable; } } if (!variableToken) return false; if (variableToken->strAt(2) == ".") // Only partially moved return false; if (moveKind != nullptr) *moveKind = kind; if (varTok != nullptr) *varTok = variableToken; return true; } static bool isOpenParenthesisMemberFunctionCallOfVarId(const Token * openParenthesisToken, unsigned 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::MOVED; value.moveKind = ValueFlow::Value::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 unsigned int varId = varTok->varId(); const Token * const endOfVarScope = var->typeStartToken()->scope()->bodyEnd; setTokenValue(varTok, value, settings); valueFlowForward(varTok->next(), endOfVarScope, var, varId, values, false, false, tokenlist, errorLogger, settings); continue; } ValueFlow::Value::MoveKind moveKind; if (!isStdMoveOrStdForwarded(tok, &moveKind, &varTok)) continue; const unsigned 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->typeStartToken()->scope()->bodyEnd; ValueFlow::Value value; value.valueType = ValueFlow::Value::MOVED; value.moveKind = moveKind; if (moveKind == ValueFlow::Value::MovedVariable) value.errorPath.emplace_back(tok, "Calling std::move(" + varTok->str() + ")"); else // if (moveKind == ValueFlow::Value::ForwardedVariable) value.errorPath.emplace_back(tok, "Calling std::forward(" + varTok->str() + ")"); value.setKnown(); std::list values; values.push_back(value); const Token * openParentesisOfMove = findOpenParentesisOfMove(varTok); const Token * endOfFunctionCall = findEndOfFunctionCallForParameter(openParentesisOfMove); if (endOfFunctionCall) valueFlowForward(const_cast(endOfFunctionCall), endOfVarScope, var, varId, values, false, false, tokenlist, errorLogger, settings); } } } 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() != "=") || (tok->astParent())) continue; // Lhs should be a variable if (!tok->astOperand1() || !tok->astOperand1()->varId() || tok->astOperand1()->hasKnownValue()) continue; const unsigned 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; const Token * const endOfVarScope = var->typeStartToken()->scope()->bodyEnd; // Rhs values.. if (!tok->astOperand2() || tok->astOperand2()->values().empty()) continue; std::list values = tok->astOperand2()->values(); 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()) values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue)); for (std::list::iterator it = values.begin(); it != values.end(); ++it) { const std::string info = "Assignment '" + tok->expressionString() + "', assigned value is " + it->infoString(); it->errorPath.emplace_back(tok->astOperand2(), info); } const bool constValue = tok->astOperand2()->isNumber(); 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 != 0); } } // Static variable initialisation? if (var->isStatic() && var->nameToken() == tok->astOperand1()) changeKnownToPossible(values); // Skip RHS const Token * nextExpression = nextAfterAstRightmostLeaf(tok); 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)); valueFlowForward(const_cast(nextExpression), endOfVarScope, var, varid, tokvalues, constValue, false, tokenlist, errorLogger, settings); values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue)); } valueFlowForward(const_cast(nextExpression), endOfVarScope, var, varid, values, constValue, false, tokenlist, errorLogger, settings); } } } struct ValueFlowConditionHandler { struct Condition { const Token *vartok; std::list true_values; std::list false_values; Condition() : vartok(nullptr), true_values(), false_values() {} }; 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, "= & %var% ;")) aliased.insert(tok->tokAt(2)->varId()); Condition cond = parse(tok); if (!cond.vartok) continue; if (cond.true_values.empty() || cond.false_values.empty()) continue; const unsigned int varid = cond.vartok->varId(); if (varid == 0U) continue; const Variable *var = cond.vartok->variable(); if (!var || !(var->isLocal() || var->isGlobal() || var->isArgument())) continue; if (aliased.find(varid) != aliased.end()) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, cond.vartok, "variable is aliased so we just skip all valueflow after condition"); continue; } if (Token::Match(tok->astParent(), "%oror%|&&")) { Token *parent = const_cast(tok->astParent()); const std::string &op(parent->str()); if (parent->astOperand1() == tok && ((op == "&&" && Token::Match(tok, "==|>=|<=|!")) || (op == "||" && Token::Match(tok, "%name%|!=")))) { for (; parent && parent->str() == op; parent = const_cast(parent->astParent())) { std::stack tokens; tokens.push(const_cast(parent->astOperand2())); bool assign = false; while (!tokens.empty()) { Token *rhstok = tokens.top(); tokens.pop(); if (!rhstok) continue; tokens.push(const_cast(rhstok->astOperand1())); tokens.push(const_cast(rhstok->astOperand2())); if (rhstok->varId() == varid) setTokenValue(rhstok, cond.true_values.front(), settings); else if (Token::Match(rhstok, "++|--|=") && Token::Match(rhstok->astOperand1(), "%varid%", varid)) { assign = true; break; } } if (assign) break; while (parent->astParent() && parent == parent->astParent()->astOperand2()) parent = const_cast(parent->astParent()); } } } const Token *top = tok->astTop(); if (top && Token::Match(top->previous(), "if|while (") && !top->previous()->isExpandedMacro()) { // does condition reassign variable? if (tok != top->astOperand2() && Token::Match(top->astOperand2(), "%oror%|&&") && isVariableChanged(top, top->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, tok, "assignment in condition"); continue; } // start token of conditional code Token *startTokens[] = {nullptr, nullptr}; // based on the comparison, should we check the if or while? bool check_if = false; bool check_else = false; if (Token::Match(tok, "==|>=|<=|!|>|<|(")) check_if = true; if (Token::Match(tok, "%name%|!=|>|<")) check_else = true; if (!check_if && !check_else) continue; // if astParent is "!" we need to invert codeblock { const Token *parent = tok->astParent(); while (parent && parent->str() == "&&") parent = parent->astParent(); if (parent && (parent->str() == "!" || Token::simpleMatch(parent, "== false"))) { check_if = !check_if; check_else = !check_else; } } // determine startToken(s) if (check_if && Token::simpleMatch(top->link(), ") {")) startTokens[0] = top->link()->next(); if (check_else && Token::simpleMatch(top->link()->linkAt(1), "} else {")) startTokens[1] = top->link()->linkAt(1)->tokAt(2); bool bail = false; for (int i = 0; i < 2; i++) { const Token *const startToken = startTokens[i]; if (!startToken) continue; std::list &values = (i == 0 ? cond.true_values : cond.false_values); if (values.size() == 1U && Token::Match(tok, "==|!|(")) { const Token *parent = tok->astParent(); while (parent && parent->str() == "&&") parent = parent->astParent(); if (parent && parent->str() == "(") values.front().setKnown(); } bool changed = forward(startTokens[i], startTokens[i]->link(), var, values, true); values.front().setPossible(); if (changed) { // TODO: The endToken should not be startTokens[i]->link() in the valueFlowForward call if (settings->debugwarnings) bailout(tokenlist, errorLogger, startTokens[i]->link(), "valueFlowAfterCondition: " + var->name() + " is changed in conditional block"); bail = true; break; } } if (bail) continue; // After conditional code.. if (Token::simpleMatch(top->link(), ") {")) { Token *after = top->link()->linkAt(1); std::string unknownFunction; if (settings->library.isScopeNoReturn(after, &unknownFunction)) { if (settings->debugwarnings && !unknownFunction.empty()) bailout(tokenlist, errorLogger, after, "possible noreturn scope"); continue; } const bool dead_if = isReturnScope(after); bool dead_else = false; if (Token::simpleMatch(after, "} else {")) { after = after->linkAt(2); if (Token::simpleMatch(after->tokAt(-2), ") ; }")) { if (settings->debugwarnings) bailout(tokenlist, errorLogger, after, "possible noreturn scope"); continue; } dead_else = isReturnScope(after); } std::list *values = nullptr; if (!dead_if && check_if) values = &cond.true_values; else if (!dead_else && check_else) values = &cond.false_values; if (values) { // 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, top->scope()->bodyEnd, var, *values, constValue); } } } } } } }; 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}; false_value = ValueFlow::Value{tok, value}; return; } const char *greaterThan = ">"; const char *lessThan = "<"; if (invert) std::swap(greaterThan, lessThan); if (Token::simpleMatch(tok, greaterThan)) { true_value = ValueFlow::Value{tok, value + 1}; false_value = ValueFlow::Value{tok, value}; } else if (Token::simpleMatch(tok, lessThan)) { true_value = ValueFlow::Value{tok, value - 1}; false_value = ValueFlow::Value{tok, value}; } } static const Token *parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value) { if (!tok->astOperand1() || !tok->astOperand2()) return nullptr; if (Token::Match(tok, "%comp%")) { if (tok->astOperand1()->hasKnownIntValue()) { setConditionalValues(tok, true, tok->astOperand1()->values().front().intvalue, true_value, false_value); return tok->astOperand2(); } else if (tok->astOperand2()->hasKnownIntValue()) { setConditionalValues(tok, false, tok->astOperand2()->values().front().intvalue, true_value, false_value); return tok->astOperand1(); } } return nullptr; } static void valueFlowAfterCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings) { ValueFlowConditionHandler handler; handler.forward = [&](Token *start, const Token *stop, const Variable *var, const std::list &values, bool constValue) { valueFlowForward( start->next(), stop, var, var->declarationId(), values, constValue, false, tokenlist, errorLogger, settings); return isVariableChanged(start, stop, var->declarationId(), var->isGlobal(), settings, tokenlist->isCPP()); }; 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(); if (!vartok->isName()) return cond; 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->isName() && (Token::Match(tok->astParent(), "%oror%|&&") || Token::Match(tok->tokAt(-2), "if|while ( %var% [)=]"))) { vartok = tok; } if (!vartok || !vartok->isName()) 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 void execute(const Token *expr, ProgramMemory * const programMemory, MathLib::bigint *result, bool *error) { if (!expr) *error = true; else if (expr->hasKnownIntValue()) { *result = expr->values().front().intvalue; } else if (expr->isNumber()) { *result = MathLib::toLongNumber(expr->str()); if (MathLib::isFloat(expr->str())) *error = true; } else if (expr->varId() > 0) { if (!programMemory->getIntValue(expr->varId(), result)) *error = true; } else if (expr->isComparisonOp()) { MathLib::bigint result1(0), result2(0); execute(expr->astOperand1(), programMemory, &result1, error); execute(expr->astOperand2(), programMemory, &result2, error); if (expr->str() == "<") *result = result1 < result2; else if (expr->str() == "<=") *result = result1 <= result2; else if (expr->str() == ">") *result = result1 > result2; else if (expr->str() == ">=") *result = result1 >= result2; else if (expr->str() == "==") *result = result1 == result2; else if (expr->str() == "!=") *result = result1 != result2; } else if (expr->str() == "=") { execute(expr->astOperand2(), programMemory, result, error); if (!*error && expr->astOperand1() && expr->astOperand1()->varId()) programMemory->setIntValue(expr->astOperand1()->varId(), *result); else *error = true; } else if (Token::Match(expr, "++|--")) { if (!expr->astOperand1() || expr->astOperand1()->varId() == 0U) *error = true; else { long long intValue; if (!programMemory->getIntValue(expr->astOperand1()->varId(), &intValue)) *error = true; else { if (intValue == 0 && expr->str() == "--" && expr->astOperand1()->variable() && expr->astOperand1()->variable()->typeStartToken()->isUnsigned()) *error = true; // overflow *result = intValue + (expr->str() == "++" ? 1 : -1); programMemory->setIntValue(expr->astOperand1()->varId(), *result); } } } else if (expr->isArithmeticalOp() && expr->astOperand1() && expr->astOperand2()) { MathLib::bigint result1(0), result2(0); execute(expr->astOperand1(), programMemory, &result1, error); execute(expr->astOperand2(), programMemory, &result2, error); if (expr->str() == "+") *result = result1 + result2; else if (expr->str() == "-") *result = result1 - result2; else if (expr->str() == "*") { if (result2 && (result1 > std::numeric_limits::max()/result2)) *error = true; else *result = result1 * result2; } else if (result2 == 0) *error = true; else if (expr->str() == "/") *result = result1 / result2; else if (expr->str() == "%") *result = result1 % result2; else if (expr->str() == "<<") { if (result2 < 0 || result1 < 0 || result2 >= MathLib::bigint_bits) { // don't perform UB *error= true; } else { *result = result1 << result2; } } else if (expr->str() == ">>") { if (result2 < 0) { // don't perform UB *error=true; } else { *result = result1 >> result2; } } } else if (expr->str() == "&&") { bool error1 = false; execute(expr->astOperand1(), programMemory, result, &error1); if (!error1 && *result == 0) *result = 0; else { bool error2 = false; execute(expr->astOperand2(), programMemory, result, &error2); if (error1 && error2) *error = true; if (error2) *result = 1; else *result = !!*result; } } else if (expr->str() == "||") { execute(expr->astOperand1(), programMemory, result, error); if (*result == 0 && *error == false) execute(expr->astOperand2(), programMemory, result, error); } else if (expr->str() == "!") { execute(expr->astOperand1(), programMemory, result, error); *result = !(*result); } else if (expr->str() == "," && expr->astOperand1() && expr->astOperand2()) { execute(expr->astOperand1(), programMemory, result, error); execute(expr->astOperand2(), programMemory, result, error); } else if (expr->str() == "[" && expr->astOperand1() && expr->astOperand2()) { const Token *tokvalue = nullptr; if (!programMemory->getTokValue(expr->astOperand1()->varId(), &tokvalue)) { auto tokvalue_it = std::find_if(expr->astOperand1()->values().begin(), expr->astOperand1()->values().end(), std::mem_fn(&ValueFlow::Value::isTokValue)); if (tokvalue_it == expr->astOperand1()->values().end()) { *error = true; return; } tokvalue = tokvalue_it->tokvalue; } if (!tokvalue || !tokvalue->isLiteral()) { *error = true; return; } const std::string strValue = tokvalue->strValue(); MathLib::bigint index = 0; execute(expr->astOperand2(), programMemory, &index, error); if (index >= 0 && index < strValue.size()) *result = strValue[index]; else if (index == strValue.size()) *result = 0; else *error = true; } else *error = true; } static bool valueFlowForLoop1(const Token *tok, unsigned int * const varid, MathLib::bigint * const num1, MathLib::bigint * const num2, MathLib::bigint * const numAfter) { tok = tok->tokAt(2); if (!Token::Match(tok, "%type%| %var% =")) return false; const Token * const vartok = Token::Match(tok, "%var% =") ? tok : tok->next(); *varid = vartok->varId(); tok = vartok->tokAt(2); const Token * const num1tok = Token::Match(tok, "%num% ;") ? tok : nullptr; if (num1tok) *num1 = MathLib::toLongNumber(num1tok->str()); while (Token::Match(tok, "%name%|%num%|%or%|+|-|*|/|&|[|]|(")) tok = (tok->str() == "(") ? tok->link()->next() : tok->next(); if (!tok || tok->str() != ";") return false; tok = tok->next(); const Token *num2tok = nullptr; if (Token::Match(tok, "%varid% <|<=|!=", vartok->varId())) { tok = tok->next(); num2tok = tok->astOperand2(); if (num2tok && num2tok->str() == "(" && !num2tok->astOperand2()) num2tok = num2tok->astOperand1(); if (!Token::Match(num2tok, "%num% ;|%oror%")) // TODO: || enlarges the scope of the condition, so it should not cause FP, but it should no lnger be part of this pattern as soon as valueFlowForLoop2 can handle an unknown RHS of || better num2tok = nullptr; } if (!num2tok) return false; *num2 = MathLib::toLongNumber(num2tok->str()) - ((tok->str()=="<=") ? 0 : 1); *numAfter = *num2 + 1; if (!num1tok) *num1 = *num2; while (tok && tok->str() != ";") tok = tok->next(); if (!Token::Match(tok, "; %varid% ++ ) {", vartok->varId()) && !Token::Match(tok, "; ++ %varid% ) {", vartok->varId())) return false; return true; } 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; unsigned int maxcount = 10000; while (result != 0 && !error && --maxcount) { 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 unsigned 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, unsigned 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->typeStartToken()->scope()->bodyEnd; else endToken = fortok->scope()->bodyEnd; std::list values; values.emplace_back(num); values.back().errorPath.emplace_back(fortok,"After for loop, " + var->name() + " has value " + values.back().infoString()); valueFlowForward(fortok->linkAt(1)->linkAt(1)->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; unsigned int varid(0); MathLib::bigint num1(0), num2(0), numAfter(0); if (valueFlowForLoop1(tok, &varid, &num1, &num2, &numAfter)) { if (num1 <= num2) { valueFlowForLoopSimplify(bodyStart, varid, false, num1, tokenlist, errorLogger, settings); valueFlowForLoopSimplify(bodyStart, varid, false, num2, tokenlist, errorLogger, settings); valueFlowForLoopSimplifyAfter(tok, varid, numAfter, tokenlist, errorLogger, settings); } else valueFlowForLoopSimplifyAfter(tok, varid, num1, tokenlist, errorLogger, settings); } else { ProgramMemory mem1, mem2, memAfter; if (valueFlowForLoop2(tok, &mem1, &mem2, &memAfter)) { std::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); } } } } } 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 unsigned int varid2 = arg->declarationId(); if (!varid2) return; valueFlowForward(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(); valueFlowForward(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(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(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()); 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, ErrorLogger *errorLogger, const Settings *settings) { for (Token *tok = tokenlist->front(); tok; 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; // TODO: Rewrite this. It does not work well to inject 1 argument at a time. const std::vector &callArguments = getArguments(tok); for (unsigned 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)); // Dont forward lifetime values argvalues.remove_if(std::mem_fn(&ValueFlow::Value::isLifetimeValue)); 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()); } // passed values are not "known".. changeKnownToPossible(argvalues); // FIXME: We need to rewrite the valueflow analysis of function calls. This does not work well. //valueFlowInjectParameter(tokenlist, errorLogger, settings, argvar, calledFunctionScope, argvalues); } } } 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->isVirtual()) 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; if (Token::Match(vardecl, "%varid% ; %varid% =", vardecl->varId())) continue; const Variable *var = vardecl->variable(); if (!var || var->nameToken() != vardecl) continue; if ((!var->isPointer() && var->type() && var->type()->needInitialization != Type::True) || !var->isLocal() || var->isStatic() || var->isExtern() || var->isReference() || var->isThrow()) continue; ValueFlow::Value uninitValue; uninitValue.setKnown(); uninitValue.valueType = ValueFlow::Value::UNINIT; std::list values; values.push_back(uninitValue); const bool constValue = true; const bool subFunction = false; valueFlowForward(vardecl->next(), vardecl->scope()->bodyEnd, var, vardecl->varId(), values, constValue, subFunction, tokenlist, errorLogger, settings); } } static bool hasContainerSizeGuard(const Token *tok, unsigned 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(unsigned int varId, const Token *start, const Token *end); static bool isContainerSizeChangedByFunction(const Token *tok) { const Token *parent = tok->astParent(); if (parent && parent->str() == "&") parent = parent->astParent(); while (parent && parent->str() == ",") parent = parent->astParent(); if (!parent) return false; if (Token::Match(parent->previous(), "%name% (")) return true; // some unsimplified template function, assume it modifies the container. if (Token::simpleMatch(parent->previous(), ">") && parent->linkAt(-1)) return true; return false; } static void valueFlowContainerReverse(const Token *tok, unsigned 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(const_cast(tok), value, settings); } } static void valueFlowContainerForward(const Token *tok, unsigned int containerId, ValueFlow::Value value, const Settings *settings, bool cpp) { while (nullptr != (tok = tok->next())) { if (Token::Match(tok, "[{}]")) break; if (Token::Match(tok, "while|for (")) { const Token *start = tok->linkAt(1)->next(); if (!Token::simpleMatch(start->link(), "{")) break; if (isContainerSizeChanged(containerId, start, start->link())) break; } if (tok->varId() != containerId) continue; if (Token::Match(tok, "%name% =")) break; if (Token::Match(tok, "%name% +=")) { if (!tok->valueType() || !tok->valueType()->container || !tok->valueType()->container->stdStringLike) break; const Token *rhs = tok->next()->astOperand2(); if (rhs->tokType() == Token::eString) value.intvalue += Token::getStrLength(rhs); else if (rhs->valueType() && rhs->valueType()->container && rhs->valueType()->container->stdStringLike) { bool found = false; for (const ValueFlow::Value &rhsval : rhs->values()) { if (rhsval.isKnown() && rhsval.isContainerSizeValue()) { value.intvalue += rhsval.intvalue; found = true; } } if (!found) break; } else break; } if (isLikelyStreamRead(cpp, tok->astParent())) 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(const_cast(tok), value, settings); } } static bool isContainerSizeChanged(unsigned int varId, const Token *start, const Token *end) { for (const Token *tok = start; tok != end; tok = tok->next()) { if (tok->varId() != varId) continue; if (!tok->valueType() || !tok->valueType()->container) return true; if (Token::Match(tok, "%name% =")) return true; if (Token::Match(tok, "%name% . %name% (")) { Library::Container::Action action = tok->valueType()->container->getAction(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 true; case Library::Container::Action::FIND: case Library::Container::Action::CHANGE_CONTENT: break; }; } } return false; } 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()) continue; if (!var->valueType() || !var->valueType()->container) continue; if (!Token::Match(var->nameToken(), "%name% ;")) 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->declarationId(), value, settings, tokenlist->isCPP()); } // after assignment for (const Scope *functionScope : symboldatabase->functionScopes) { for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) { if (Token::Match(tok, "[;{}] %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->varId(), value, settings, tokenlist->isCPP()); } } } } // 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(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 Variable *var, const std::list &values, bool) { // TODO: Forward multiple values if (values.empty()) return false; valueFlowContainerForward(start, var->declarationId(), values.front(), settings, tokenlist->isCPP()); return isContainerSizeChanged(var->declarationId(), start, stop); }; 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; ValueFlow::Value value(tok, 0LL); value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE; cond.true_values.emplace_back(value); cond.false_values.emplace_back(value); cond.vartok = vartok; 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(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::Match(tok, "=|==") || !tok->astOperand1() || !tok->astOperand2()) continue; if (!tok->scope()->isExecutable()) continue; if (!tok->astOperand2()->hasKnownIntValue()) continue; const bool assign = tok->isAssignmentOp(); ValueFlow::Value v(tok->astOperand2()->values().front()); if (assign) v.errorPath.emplace_back(tok, tok->astOperand1()->expressionString() + " is assigned value " + MathLib::toString(v.intvalue)); else { v.errorPath.emplace_back(tok, "Assuming that " + tok->astOperand1()->expressionString() + " has the value " + MathLib::toString(v.intvalue)); v.condition = tok; } FwdAnalysis fwdAnalysis(tokenlist->isCPP(), settings->library); 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; for (const Token *tok2 : fwdAnalysis.valueFlow(tok->astOperand1(), startToken, endToken)) { const Scope *s = tok2->scope(); while (s && s != tok->scope()) s = s->nestedIn; v.valueKind = assign && s ? ValueFlow::Value::ValueKind::Known : ValueFlow::Value::ValueKind::Possible; setTokenValue(const_cast(tok2), v, settings); } } } ValueFlow::Value::Value(const Token *c, long long val) : valueType(INT), intvalue(val), tokvalue(nullptr), floatValue(0.0), moveKind(NonMovedVariable), varvalue(val), condition(c), varId(0U), conditional(false), defaultArg(false), lifetimeKind(Object), valueKind(ValueKind::Possible) { errorPath.emplace_back(c, "Assuming that condition '" + c->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 CONTAINER_SIZE: return "size=" + MathLib::toString(intvalue); case LIFETIME: return "lifetime=" + tokvalue->str(); }; throw InternalError(nullptr, "Invalid ValueFlow Value type"); } const ValueFlow::Value *ValueFlow::valueFlowConstantFoldAST(const 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); valueFlowGlobalStaticVar(tokenlist, settings); valueFlowPointerAlias(tokenlist); valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings); valueFlowFunctionReturn(tokenlist, errorLogger); valueFlowBitAnd(tokenlist); valueFlowSameExpressions(tokenlist); valueFlowFwdAnalysis(tokenlist, settings); // Temporary hack.. run valueflow until there is nothing to update or timeout expires const std::time_t timeout = std::time(0) + TIMEOUT; std::size_t values = 0; while (std::time(0) < timeout && values < getTotalValues(tokenlist)) { values = getTotalValues(tokenlist); valueFlowRightShift(tokenlist); valueFlowOppositeCondition(symboldatabase, settings); valueFlowTerminatingCondition(tokenlist, symboldatabase, settings); valueFlowBeforeCondition(tokenlist, symboldatabase, errorLogger, settings); valueFlowAfterMove(tokenlist, symboldatabase, errorLogger, settings); valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, settings); valueFlowAfterCondition(tokenlist, symboldatabase, errorLogger, settings); valueFlowSwitchVariable(tokenlist, symboldatabase, errorLogger, settings); valueFlowForLoop(tokenlist, symboldatabase, errorLogger, settings); valueFlowSubFunction(tokenlist, errorLogger, settings); valueFlowFunctionDefaultParameter(tokenlist, symboldatabase, errorLogger, settings); valueFlowUninit(tokenlist, symboldatabase, errorLogger, settings); if (tokenlist->isCPP()) { valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings); valueFlowContainerAfterCondition(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"; }