/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2020 Cppcheck team. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ //--------------------------------------------------------------------------- #include "astutils.h" #include "config.h" #include "library.h" #include "mathlib.h" #include "settings.h" #include "symboldatabase.h" #include "token.h" #include "valueflow.h" #include #include #include #include template)> void visitAstNodesGeneric(T *ast, std::function visitor) { std::stack tokens; tokens.push(ast); while (!tokens.empty()) { T *tok = tokens.top(); tokens.pop(); if (!tok) continue; ChildrenToVisit c = visitor(tok); if (c == ChildrenToVisit::done) break; if (c == ChildrenToVisit::op1 || c == ChildrenToVisit::op1_and_op2) tokens.push(tok->astOperand1()); if (c == ChildrenToVisit::op2 || c == ChildrenToVisit::op1_and_op2) tokens.push(tok->astOperand2()); } } void visitAstNodes(const Token *ast, std::function visitor) { visitAstNodesGeneric(ast, std::move(visitor)); } void visitAstNodes(Token *ast, std::function visitor) { visitAstNodesGeneric(ast, std::move(visitor)); } static void astFlattenRecursive(const Token *tok, std::vector *result, const char* op, nonneg int depth = 0) { ++depth; if (!tok || depth >= 100) return; if (tok->str() == op) { astFlattenRecursive(tok->astOperand1(), result, op, depth); astFlattenRecursive(tok->astOperand2(), result, op, depth); } else { result->push_back(tok); } } std::vector astFlatten(const Token* tok, const char* op) { std::vector result; astFlattenRecursive(tok, &result, op); return result; } bool astHasToken(const Token* root, const Token * tok) { if (!root) return false; if (root == tok) return true; return astHasToken(root->astOperand1(), tok) || astHasToken(root->astOperand2(), tok); } bool astHasVar(const Token * tok, nonneg int varid) { if (!tok) return false; if (tok->varId() == varid) return true; return astHasVar(tok->astOperand1(), varid) || astHasVar(tok->astOperand2(), varid); } static bool astIsCharWithSign(const Token *tok, ValueType::Sign sign) { if (!tok) return false; const ValueType *valueType = tok->valueType(); if (!valueType) return false; return valueType->type == ValueType::Type::CHAR && valueType->pointer == 0U && valueType->sign == sign; } bool astIsSignedChar(const Token *tok) { return astIsCharWithSign(tok, ValueType::Sign::SIGNED); } bool astIsUnknownSignChar(const Token *tok) { return astIsCharWithSign(tok, ValueType::Sign::UNKNOWN_SIGN); } bool astIsIntegral(const Token *tok, bool unknown) { const ValueType *vt = tok ? tok->valueType() : nullptr; if (!vt) return unknown; return vt->isIntegral() && vt->pointer == 0U; } bool astIsFloat(const Token *tok, bool unknown) { const ValueType *vt = tok ? tok->valueType() : nullptr; if (!vt) return unknown; return vt->type >= ValueType::Type::FLOAT && vt->pointer == 0U; } bool astIsBool(const Token *tok) { return tok && (tok->isBoolean() || (tok->valueType() && tok->valueType()->type == ValueType::Type::BOOL && !tok->valueType()->pointer)); } bool astIsPointer(const Token *tok) { return tok && tok->valueType() && tok->valueType()->pointer; } bool astIsSmartPointer(const Token* tok) { return tok && tok->valueType() && tok->valueType()->smartPointerTypeToken; } bool astIsIterator(const Token *tok) { return tok && tok->valueType() && tok->valueType()->type == ValueType::Type::ITERATOR; } bool astIsContainer(const Token *tok) { return getLibraryContainer(tok) != nullptr && tok->valueType()->type != ValueType::Type::ITERATOR; } std::string astCanonicalType(const Token *expr) { if (!expr) return ""; std::pair decl = Token::typeDecl(expr); if (decl.first && decl.second) { std::string ret; for (const Token *type = decl.first; Token::Match(type,"%name%|::") && type != decl.second; type = type->next()) { if (!Token::Match(type, "const|static")) ret += type->str(); } return ret; } return ""; } static bool match(const Token *tok, const std::string &rhs) { if (tok->str() == rhs) return true; if (!tok->varId() && tok->hasKnownIntValue() && MathLib::toString(tok->values().front().intvalue) == rhs) return true; return false; } const Token * astIsVariableComparison(const Token *tok, const std::string &comp, const std::string &rhs, const Token **vartok) { if (!tok) return nullptr; const Token *ret = nullptr; if (tok->isComparisonOp()) { if (tok->astOperand1() && match(tok->astOperand1(), rhs)) { // Invert comparator std::string s = tok->str(); if (s[0] == '>') s[0] = '<'; else if (s[0] == '<') s[0] = '>'; if (s == comp) { ret = tok->astOperand2(); } } else if (tok->str() == comp && tok->astOperand2() && match(tok->astOperand2(), rhs)) { ret = tok->astOperand1(); } } else if (comp == "!=" && rhs == std::string("0")) { ret = tok; } else if (comp == "==" && rhs == std::string("0")) { if (tok->str() == "!") { ret = tok->astOperand1(); // handle (!(x!=0)) as (x==0) astIsVariableComparison(ret, "!=", "0", &ret); } } while (ret && ret->str() == ".") ret = ret->astOperand2(); if (ret && ret->str() == "=" && ret->astOperand1() && ret->astOperand1()->varId()) ret = ret->astOperand1(); else if (ret && ret->varId() == 0U) ret = nullptr; if (vartok) *vartok = ret; return ret; } bool isTemporary(bool cpp, const Token* tok, const Library* library, bool unknown) { if (!tok) return false; if (Token::simpleMatch(tok, ".")) return (tok->originalName() != "->" && isTemporary(cpp, tok->astOperand1(), library)) || isTemporary(cpp, tok->astOperand2(), library); if (Token::Match(tok, ",|::")) return isTemporary(cpp, tok->astOperand2(), library); if (tok->isCast() || (cpp && isCPPCast(tok))) return isTemporary(cpp, tok->astOperand2(), library); if (Token::Match(tok, "?|.|[|++|--|%name%|%assign%")) return false; if (tok->isUnaryOp("*")) return false; if (Token::Match(tok, "&|<<|>>") && isLikelyStream(cpp, tok->astOperand1())) return false; if (Token::Match(tok->previous(), ">|%name% (")) { const Token* ftok = nullptr; if (tok->previous()->link()) ftok = tok->previous()->link()->previous(); else ftok = tok->previous(); if (!ftok) return false; if (const Function * f = ftok->function()) { return !Function::returnsReference(f, true); } else if (library) { std::string returnType = library->returnValueType(ftok); return !returnType.empty() && returnType.back() != '&'; } else { return unknown; } } if (tok->isCast()) return false; // Currying a function is unknown in cppcheck if (Token::simpleMatch(tok, "(") && Token::simpleMatch(tok->astOperand1(), "(")) return unknown; return true; } static bool isFunctionCall(const Token* tok) { if (Token::Match(tok, "%name% (")) return true; if (Token::Match(tok, "%name% <") && Token::simpleMatch(tok->next()->link(), "> (")) return true; if (Token::Match(tok, "%name% ::")) return isFunctionCall(tok->tokAt(2)); return false; } static bool hasToken(const Token * startTok, const Token * stopTok, const Token * tok) { for (const Token * tok2 = startTok; tok2 != stopTok; tok2 = tok2->next()) { if (tok2 == tok) return true; } return false; } template )> static T* nextAfterAstRightmostLeafGeneric(T* tok) { const Token * rightmostLeaf = tok; if (!rightmostLeaf || !rightmostLeaf->astOperand1()) return nullptr; do { if (const Token* lam = findLambdaEndToken(rightmostLeaf)) { rightmostLeaf = lam; break; } if (rightmostLeaf->astOperand2()) rightmostLeaf = rightmostLeaf->astOperand2(); else rightmostLeaf = rightmostLeaf->astOperand1(); } while (rightmostLeaf->astOperand1()); while (Token::Match(rightmostLeaf->next(), "]|)") && !hasToken(rightmostLeaf->next()->link(), rightmostLeaf->next(), tok)) rightmostLeaf = rightmostLeaf->next(); if (rightmostLeaf->str() == "{" && rightmostLeaf->link()) rightmostLeaf = rightmostLeaf->link(); return rightmostLeaf->next(); } const Token* nextAfterAstRightmostLeaf(const Token* tok) { return nextAfterAstRightmostLeafGeneric(tok); } Token* nextAfterAstRightmostLeaf(Token* tok) { return nextAfterAstRightmostLeafGeneric(tok); } const Token* astParentSkipParens(const Token* tok) { return astParentSkipParens(const_cast(tok)); } Token* astParentSkipParens(Token* tok) { if (!tok) return nullptr; Token * parent = tok->astParent(); if (!Token::simpleMatch(parent, "(")) return parent; if (parent->link() != nextAfterAstRightmostLeaf(tok)) return parent; return astParentSkipParens(parent); } const Token* getParentMember(const Token * tok) { if (!tok) return tok; const Token * parent = tok->astParent(); if (!Token::simpleMatch(parent, ".")) return tok; if (tok == parent->astOperand2()) return parent->astOperand1(); const Token * gparent = parent->astParent(); if (!Token::simpleMatch(gparent, ".") || gparent->astOperand2() != parent) return tok; if (gparent->astOperand1()) return gparent->astOperand1(); return tok; } const Token* getParentLifetime(const Token* tok) { if (!tok) return tok; const Variable* var = tok->variable(); // TODO: Call getLifetimeVariable for deeper analysis if (!var) return tok; if (var->isLocal() || var->isArgument()) return tok; const Token* parent = getParentMember(tok); if (parent != tok) return getParentLifetime(parent); return tok; } bool astIsLHS(const Token* tok) { if (!tok) return false; const Token* parent = tok->astParent(); if (!parent) return false; if (!parent->astOperand1()) return false; if (!parent->astOperand2()) return false; return parent->astOperand1() == tok; } bool astIsRHS(const Token* tok) { if (!tok) return false; const Token* parent = tok->astParent(); if (!parent) return false; if (!parent->astOperand1()) return false; if (!parent->astOperand2()) return false; return parent->astOperand2() == tok; } template )> static T* getCondTokImpl(T* tok) { if (!tok) return nullptr; if (Token::simpleMatch(tok, "(")) return getCondTok(tok->previous()); if (Token::simpleMatch(tok, "for") && Token::simpleMatch(tok->next()->astOperand2(), ";") && tok->next()->astOperand2()->astOperand2()) return tok->next()->astOperand2()->astOperand2()->astOperand1(); if (Token::simpleMatch(tok->next()->astOperand2(), ";")) return tok->next()->astOperand2()->astOperand1(); return tok->next()->astOperand2(); } template )> static T* getCondTokFromEndImpl(T* endBlock) { if (!Token::simpleMatch(endBlock, "}")) return nullptr; T* startBlock = endBlock->link(); if (!Token::simpleMatch(startBlock, "{")) return nullptr; if (Token::simpleMatch(startBlock->previous(), ")")) { return getCondTok(startBlock->previous()->link()); } else if (Token::simpleMatch(startBlock->tokAt(-2), "} else {")) { return getCondTokFromEnd(startBlock->tokAt(-2)); } return nullptr; } Token* getCondTok(Token* tok) { return getCondTokImpl(tok); } const Token* getCondTok(const Token* tok) { return getCondTokImpl(tok); } Token* getCondTokFromEnd(Token* endBlock) { return getCondTokFromEndImpl(endBlock); } const Token* getCondTokFromEnd(const Token* endBlock) { return getCondTokFromEndImpl(endBlock); } bool extractForLoopValues(const Token *forToken, nonneg int * const varid, bool * const knownInitValue, MathLib::bigint * const initValue, bool * const partialCond, MathLib::bigint * const stepValue, MathLib::bigint * const lastValue) { if (!Token::simpleMatch(forToken, "for (") || !Token::simpleMatch(forToken->next()->astOperand2(), ";")) return false; const Token *initExpr = forToken->next()->astOperand2()->astOperand1(); const Token *condExpr = forToken->next()->astOperand2()->astOperand2()->astOperand1(); const Token *incExpr = forToken->next()->astOperand2()->astOperand2()->astOperand2(); if (!initExpr || !initExpr->isBinaryOp() || initExpr->str() != "=" || !Token::Match(initExpr->astOperand1(), "%var%")) return false; *varid = initExpr->astOperand1()->varId(); *knownInitValue = initExpr->astOperand2()->hasKnownIntValue(); *initValue = (*knownInitValue) ? initExpr->astOperand2()->getKnownIntValue() : 0; *partialCond = Token::Match(condExpr, "%oror%|&&"); visitAstNodes(condExpr, [varid, &condExpr](const Token *tok) { if (Token::Match(tok, "%oror%|&&")) return ChildrenToVisit::op1_and_op2; if (Token::Match(tok, "<|<=") && tok->isBinaryOp() && tok->astOperand1()->varId() == *varid && tok->astOperand2()->hasKnownIntValue()) { if (Token::Match(condExpr, "%oror%|&&") || tok->astOperand2()->getKnownIntValue() < condExpr->astOperand2()->getKnownIntValue()) condExpr = tok; } return ChildrenToVisit::none; }); if (!Token::Match(condExpr, "<|<=") || !condExpr->isBinaryOp() || condExpr->astOperand1()->varId() != *varid || !condExpr->astOperand2()->hasKnownIntValue()) return false; if (!incExpr || !incExpr->isUnaryOp("++") || incExpr->astOperand1()->varId() != *varid) return false; *stepValue = 1; if (condExpr->str() == "<") *lastValue = condExpr->astOperand2()->getKnownIntValue() - 1; else *lastValue = condExpr->astOperand2()->getKnownIntValue(); return true; } static const Token * getVariableInitExpression(const Variable * var) { if (!var || !var->declEndToken()) return nullptr; if (Token::Match(var->declEndToken(), "; %varid% =", var->declarationId())) return var->declEndToken()->tokAt(2)->astOperand2(); return var->declEndToken()->astOperand2(); } static bool isInLoopCondition(const Token * tok) { return Token::Match(tok->astTop()->previous(), "for|while ("); } /// If tok2 comes after tok1 bool precedes(const Token * tok1, const Token * tok2) { if (!tok1) return false; if (!tok2) return false; return tok1->index() < tok2->index(); } bool isAliasOf(const Token *tok, nonneg int varid) { if (tok->varId() == varid) return false; for (const ValueFlow::Value &val : tok->values()) { if (!val.isLocalLifetimeValue()) continue; if (val.isInconclusive()) continue; if (val.tokvalue->varId() == varid) return true; } return false; } static bool isAliased(const Token *startTok, const Token *endTok, nonneg int varid) { if (!precedes(startTok, endTok)) return false; for (const Token *tok = startTok; tok != endTok; tok = tok->next()) { if (Token::Match(tok, "= & %varid% ;", varid)) return true; if (isAliasOf(tok, varid)) return true; } return false; } bool isAliased(const Variable *var) { if (!var) return false; if (!var->scope()) return false; const Token *start = var->declEndToken(); if (!start) return false; return isAliased(start, var->scope()->bodyEnd, var->declarationId()); } bool exprDependsOnThis(const Token* expr, nonneg int depth) { if (!expr) return false; if (depth >= 1000) // Abort recursion to avoid stack overflow return true; ++depth; // calling nonstatic method? if (Token::Match(expr->previous(), "!!:: %name% (") && expr->function() && expr->function()->nestedIn && expr->function()->nestedIn->isClassOrStruct()) { // is it a method of this? const Scope* fScope = expr->scope(); while (!fScope->functionOf && fScope->nestedIn) fScope = fScope->nestedIn; const Scope* nestedIn = fScope->functionOf; if (nestedIn && nestedIn->function) nestedIn = nestedIn->function->token->scope(); while (nestedIn && nestedIn != expr->function()->nestedIn) { nestedIn = nestedIn->nestedIn; } return nestedIn == expr->function()->nestedIn; } else if (Token::Match(expr, "%var%") && expr->variable()) { const Variable* var = expr->variable(); return (var->isPrivate() || var->isPublic() || var->isProtected()); } if (Token::simpleMatch(expr, ".")) return exprDependsOnThis(expr->astOperand1(), depth); return exprDependsOnThis(expr->astOperand1(), depth) || exprDependsOnThis(expr->astOperand2(), depth); } /// This takes a token that refers to a variable and it will return the token /// to the expression that the variable is assigned to. If its not valid to /// make such substitution then it will return the original token. static const Token * followVariableExpression(const Token * tok, bool cpp, const Token * end = nullptr) { if (!tok) return tok; // Skip following variables that is across multiple files if (end && end->fileIndex() != tok->fileIndex()) return tok; // Skip array access if (Token::Match(tok, "%var% [")) return tok; // Skip pointer indirection if (tok->astParent() && tok->isUnaryOp("*")) return tok; // Skip following variables if it is used in an assignment if (Token::Match(tok->next(), "%assign%")) return tok; const Variable * var = tok->variable(); const Token * varTok = getVariableInitExpression(var); if (!varTok) return tok; // Bailout. If variable value depends on value of "this". if (exprDependsOnThis(varTok)) return tok; // Skip array access if (Token::simpleMatch(varTok, "[")) return tok; if (var->isVolatile()) return tok; if (!var->isLocal() && !var->isConst()) return tok; if (var->isStatic() && !var->isConst()) return tok; if (var->isArgument()) return tok; const Token * lastTok = precedes(tok, end) ? end : tok; // If this is in a loop then check if variables are modified in the entire scope const Token * endToken = (isInLoopCondition(tok) || isInLoopCondition(varTok) || var->scope() != tok->scope()) ? var->scope()->bodyEnd : lastTok; if (!var->isConst() && (!precedes(varTok, endToken) || isVariableChanged(varTok, endToken, tok->varId(), false, nullptr, cpp))) return tok; if (precedes(varTok, endToken) && isAliased(varTok, endToken, tok->varId())) return tok; // Start at beginning of initialization const Token * startToken = varTok; while (Token::Match(startToken, "%op%|.|(|{") && startToken->astOperand1()) startToken = startToken->astOperand1(); // Skip if the variable its referring to is modified for (const Token * tok2 = startToken; tok2 != endToken; tok2 = tok2->next()) { if (Token::simpleMatch(tok2, ";")) break; if (tok2->astParent() && tok2->isUnaryOp("*")) return tok; if (tok2->tokType() == Token::eIncDecOp || tok2->isAssignmentOp() || Token::Match(tok2, "%name% .|[|++|--|%assign%")) { return tok; } if (Token::Match(tok2, "%name% (")) // Bailout when function call is seen return tok; if (const Variable * var2 = tok2->variable()) { if (!var2->scope()) return tok; const Token * endToken2 = var2->scope() != tok->scope() ? var2->scope()->bodyEnd : endToken; if (!var2->isLocal() && !var2->isConst() && !var2->isArgument()) return tok; if (var2->isStatic() && !var2->isConst()) return tok; if (!var2->isConst() && (!precedes(tok2, endToken2) || isVariableChanged(tok2, endToken2, tok2->varId(), false, nullptr, cpp))) return tok; if (precedes(tok2, endToken2) && isAliased(tok2, endToken2, tok2->varId())) return tok; // Recognized as a variable but the declaration is unknown } else if (tok2->varId() > 0) { return tok; } else if (tok2->tokType() == Token::eName && !Token::Match(tok2, "sizeof|decltype|typeof") && !tok2->function()) { return tok; } } return varTok; } static void followVariableExpressionError(const Token *tok1, const Token *tok2, ErrorPath* errors) { if (!errors) return; if (!tok1) return; if (!tok2) return; ErrorPathItem item = std::make_pair(tok2, "'" + tok1->str() + "' is assigned value '" + tok2->expressionString() + "' here."); if (std::find(errors->begin(), errors->end(), item) != errors->end()) return; errors->push_back(item); } static void findTokenValue(const Token* const tok, std::function pred, std::function f) { auto x = std::find_if(tok->values().begin(), tok->values().end(), pred); if (x != tok->values().end()) f(*x); } bool isEqualKnownValue(const Token * const tok1, const Token * const tok2) { bool result = false; findTokenValue(tok1, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v1) { findTokenValue(tok2, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v2) { result = v1.equalValue(v2); }); }); return result; } bool isDifferentKnownValues(const Token * const tok1, const Token * const tok2) { bool result = false; findTokenValue(tok1, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v1) { findTokenValue(tok2, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v2) { result = !v1.equalValue(v2); }); }); return result; } static bool isSameConstantValue(bool macro, const Token * const tok1, const Token * const tok2) { if (tok1 == nullptr || tok2 == nullptr) return false; if (!tok1->isNumber() || !tok2->isNumber()) return false; if (macro && (tok1->isExpandedMacro() || tok2->isExpandedMacro() || tok1->isTemplateArg() || tok2->isTemplateArg())) return false; const ValueType * v1 = tok1->valueType(); const ValueType * v2 = tok2->valueType(); if (!v1 || !v2 || v1->sign != v2->sign || v1->type != v2->type || v1->pointer != v2->pointer) return false; return isEqualKnownValue(tok1, tok2); } static bool astIsBoolLike(const Token* tok) { return astIsBool(tok) || astIsPointer(tok) || astIsSmartPointer(tok); } bool isSameExpression(bool cpp, bool macro, const Token *tok1, const Token *tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors) { if (tok1 == nullptr && tok2 == nullptr) return true; if (tok1 == nullptr || tok2 == nullptr) return false; if (cpp) { if (tok1->str() == "." && tok1->astOperand1() && tok1->astOperand1()->str() == "this") tok1 = tok1->astOperand2(); if (tok2->str() == "." && tok2->astOperand1() && tok2->astOperand1()->str() == "this") tok2 = tok2->astOperand2(); } // Skip double not if (Token::simpleMatch(tok1, "!") && Token::simpleMatch(tok1->astOperand1(), "!") && !Token::simpleMatch(tok1->astParent(), "=")) { return isSameExpression(cpp, macro, tok1->astOperand1()->astOperand1(), tok2, library, pure, followVar, errors); } if (Token::simpleMatch(tok2, "!") && Token::simpleMatch(tok2->astOperand1(), "!") && !Token::simpleMatch(tok2->astParent(), "=")) { return isSameExpression(cpp, macro, tok1, tok2->astOperand1()->astOperand1(), library, pure, followVar, errors); } if (tok1->str() != tok2->str() && isDifferentKnownValues(tok1, tok2)) return false; if (isSameConstantValue(macro, tok1, tok2)) return true; // Follow variable if (followVar && tok1->str() != tok2->str() && (Token::Match(tok1, "%var%") || Token::Match(tok2, "%var%"))) { const Token * varTok1 = followVariableExpression(tok1, cpp, tok2); if ((varTok1->str() == tok2->str()) || isSameConstantValue(macro, varTok1, tok2)) { followVariableExpressionError(tok1, varTok1, errors); return isSameExpression(cpp, macro, varTok1, tok2, library, true, followVar, errors); } const Token * varTok2 = followVariableExpression(tok2, cpp, tok1); if ((tok1->str() == varTok2->str()) || isSameConstantValue(macro, tok1, varTok2)) { followVariableExpressionError(tok2, varTok2, errors); return isSameExpression(cpp, macro, tok1, varTok2, library, true, followVar, errors); } if ((varTok1->str() == varTok2->str()) || isSameConstantValue(macro, varTok1, varTok2)) { followVariableExpressionError(tok1, varTok1, errors); followVariableExpressionError(tok2, varTok2, errors); return isSameExpression(cpp, macro, varTok1, varTok2, library, true, followVar, errors); } } if (tok1->varId() != tok2->varId() || tok1->str() != tok2->str() || tok1->originalName() != tok2->originalName()) { if ((Token::Match(tok1,"<|>") && Token::Match(tok2,"<|>")) || (Token::Match(tok1,"<=|>=") && Token::Match(tok2,"<=|>="))) { return isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand2(), library, pure, followVar, errors) && isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand1(), library, pure, followVar, errors); } const Token* condTok = nullptr; const Token* exprTok = nullptr; if (Token::Match(tok1, "==|!=")) { condTok = tok1; exprTok = tok2; } else if (Token::Match(tok2, "==|!=")) { condTok = tok2; exprTok = tok1; } if (condTok && condTok->astOperand1() && condTok->astOperand2() && !Token::Match(exprTok, "%comp%")) { const Token* varTok1 = nullptr; const Token* varTok2 = exprTok; const ValueFlow::Value* value = nullptr; if (condTok->astOperand1()->hasKnownIntValue()) { value = &condTok->astOperand1()->values().front(); varTok1 = condTok->astOperand2(); } else if (condTok->astOperand2()->hasKnownIntValue()) { value = &condTok->astOperand2()->values().front(); varTok1 = condTok->astOperand1(); } if (Token::simpleMatch(exprTok, "!")) varTok2 = exprTok->astOperand1(); bool compare = false; if (value) { if (value->intvalue == 0 && Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "==")) { compare = true; } else if (value->intvalue == 0 && !Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "!=")) { compare = true; } else if (value->intvalue != 0 && Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "!=")) { compare = true; } else if (value->intvalue != 0 && !Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "==")) { compare = true; } } if (compare && astIsBoolLike(varTok1) && astIsBoolLike(varTok2)) return isSameExpression(cpp, macro, varTok1, varTok2, library, pure, followVar, errors); } return false; } if (macro && (tok1->isExpandedMacro() || tok2->isExpandedMacro() || tok1->isTemplateArg() || tok2->isTemplateArg())) return false; if (tok1->isComplex() != tok2->isComplex()) return false; if (tok1->isLong() != tok2->isLong()) return false; if (tok1->isUnsigned() != tok2->isUnsigned()) return false; if (tok1->isSigned() != tok2->isSigned()) return false; if (pure && tok1->isName() && tok1->next()->str() == "(" && tok1->str() != "sizeof" && !(tok1->variable() && tok1 == tok1->variable()->nameToken())) { if (!tok1->function()) { if (Token::simpleMatch(tok1->previous(), ".")) { const Token *lhs = tok1->previous(); while (Token::Match(lhs, "(|.|[")) lhs = lhs->astOperand1(); if (!lhs) return false; const bool lhsIsConst = (lhs->variable() && lhs->variable()->isConst()) || (lhs->valueType() && lhs->valueType()->constness > 0) || (Token::Match(lhs, "%var% . %name% (") && library.isFunctionConst(lhs->tokAt(2))); if (!lhsIsConst) return false; } else { const Token * ftok = tok1; if (Token::simpleMatch(tok1->previous(), "::")) ftok = tok1->previous(); if (!library.isFunctionConst(ftok) && !ftok->isAttributeConst() && !ftok->isAttributePure()) return false; } } else { if (tok1->function() && !tok1->function()->isConst() && !tok1->function()->isAttributeConst() && !tok1->function()->isAttributePure()) return false; } } // templates/casts if ((Token::Match(tok1, "%name% <") && tok1->next()->link()) || (Token::Match(tok2, "%name% <") && tok2->next()->link())) { // non-const template function that is not a dynamic_cast => return false if (pure && Token::simpleMatch(tok1->next()->link(), "> (") && !(tok1->function() && tok1->function()->isConst()) && tok1->str() != "dynamic_cast") return false; // some template/cast stuff.. check that the template arguments are same const Token *t1 = tok1->next(); const Token *t2 = tok2->next(); const Token *end1 = t1->link(); const Token *end2 = t2->link(); while (t1 && t2 && t1 != end1 && t2 != end2) { if (t1->str() != t2->str()) return false; t1 = t1->next(); t2 = t2->next(); } if (t1 != end1 || t2 != end2) return false; } if (tok1->tokType() == Token::eIncDecOp || tok1->isAssignmentOp()) return false; // bailout when we see ({..}) if (tok1->str() == "{") return false; // cast => assert that the casts are equal if (tok1->str() == "(" && tok1->previous() && !tok1->previous()->isName() && !(tok1->previous()->str() == ">" && tok1->previous()->link())) { const Token *t1 = tok1->next(); const Token *t2 = tok2->next(); while (t1 && t2 && t1->str() == t2->str() && t1->isLong() == t2->isLong() && t1->isUnsigned() == t2->isUnsigned() && t1->isSigned() == t2->isSigned() && (t1->isName() || t1->str() == "*")) { t1 = t1->next(); t2 = t2->next(); } if (!t1 || !t2 || t1->str() != ")" || t2->str() != ")") return false; } bool noncommutativeEquals = isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand1(), library, pure, followVar, errors); noncommutativeEquals = noncommutativeEquals && isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand2(), library, pure, followVar, errors); if (noncommutativeEquals) return true; // in c++, a+b might be different to b+a, depending on the type of a and b if (cpp && tok1->str() == "+" && tok1->isBinaryOp()) { const ValueType* vt1 = tok1->astOperand1()->valueType(); const ValueType* vt2 = tok1->astOperand2()->valueType(); if (!(vt1 && (vt1->type >= ValueType::VOID || vt1->pointer) && vt2 && (vt2->type >= ValueType::VOID || vt2->pointer))) return false; } const bool commutative = tok1->isBinaryOp() && Token::Match(tok1, "%or%|%oror%|+|*|&|&&|^|==|!="); bool commutativeEquals = commutative && isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand1(), library, pure, followVar, errors); commutativeEquals = commutativeEquals && isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand2(), library, pure, followVar, errors); return commutativeEquals; } static bool isZeroBoundCond(const Token * const cond) { if (cond == nullptr) return false; // Assume unsigned // TODO: Handle reverse conditions const bool isZero = cond->astOperand2()->getValue(0); if (cond->str() == "==" || cond->str() == ">=") return isZero; if (cond->str() == "<=") return true; if (cond->str() == "<") return !isZero; if (cond->str() == ">") return false; return false; } bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const Library& library, bool pure, bool followVar, ErrorPath* errors) { if (!cond1 || !cond2) return false; if (cond1->str() == "&&" && cond2->str() == "&&") { for (const Token* tok1: { cond1->astOperand1(), cond1->astOperand2() }) { for (const Token* tok2: { cond2->astOperand1(), cond2->astOperand2() }) { if (isSameExpression(cpp, true, tok1, tok2, library, pure, followVar, errors)) { if (isOppositeCond(isNot, cpp, tok1->astSibling(), tok2->astSibling(), library, pure, followVar, errors)) return true; } } } } if (cond1->str() == "!") { if (cond2->str() == "!=") { if (cond2->astOperand1() && cond2->astOperand1()->str() == "0") return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), library, pure, followVar, errors); if (cond2->astOperand2() && cond2->astOperand2()->str() == "0") return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors); } return isSameExpression(cpp, true, cond1->astOperand1(), cond2, library, pure, followVar, errors); } if (cond2->str() == "!") return isOppositeCond(isNot, cpp, cond2, cond1, library, pure, followVar, errors); if (!isNot) { if (cond1->str() == "==" && cond2->str() == "==") { if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors)) return isDifferentKnownValues(cond1->astOperand2(), cond2->astOperand2()); if (isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), library, pure, followVar, errors)) return isDifferentKnownValues(cond1->astOperand1(), cond2->astOperand1()); } // TODO: Handle reverse conditions if (Library::isContainerYield(cond1, Library::Container::Yield::EMPTY, "empty") && Library::isContainerYield(cond2->astOperand1(), Library::Container::Yield::SIZE, "size") && cond1->astOperand1()->astOperand1()->varId() == cond2->astOperand1()->astOperand1()->astOperand1()->varId()) { return !isZeroBoundCond(cond2); } if (Library::isContainerYield(cond2, Library::Container::Yield::EMPTY, "empty") && Library::isContainerYield(cond1->astOperand1(), Library::Container::Yield::SIZE, "size") && cond2->astOperand1()->astOperand1()->varId() == cond1->astOperand1()->astOperand1()->astOperand1()->varId()) { return !isZeroBoundCond(cond1); } } if (!cond1->isComparisonOp() || !cond2->isComparisonOp()) return false; const std::string &comp1 = cond1->str(); // condition found .. get comparator std::string comp2; if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors) && isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), library, pure, followVar, errors)) { comp2 = cond2->str(); } else if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), library, pure, followVar, errors) && isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand1(), library, pure, followVar, errors)) { comp2 = cond2->str(); if (comp2[0] == '>') comp2[0] = '<'; else if (comp2[0] == '<') comp2[0] = '>'; } if (!isNot && comp2.empty()) { const Token *expr1 = nullptr, *value1 = nullptr, *expr2 = nullptr, *value2 = nullptr; std::string op1 = cond1->str(), op2 = cond2->str(); if (cond1->astOperand2()->hasKnownIntValue()) { expr1 = cond1->astOperand1(); value1 = cond1->astOperand2(); } else if (cond1->astOperand1()->hasKnownIntValue()) { expr1 = cond1->astOperand2(); value1 = cond1->astOperand1(); if (op1[0] == '>') op1[0] = '<'; else if (op1[0] == '<') op1[0] = '>'; } if (cond2->astOperand2()->hasKnownIntValue()) { expr2 = cond2->astOperand1(); value2 = cond2->astOperand2(); } else if (cond2->astOperand1()->hasKnownIntValue()) { expr2 = cond2->astOperand2(); value2 = cond2->astOperand1(); if (op2[0] == '>') op2[0] = '<'; else if (op2[0] == '<') op2[0] = '>'; } if (!expr1 || !value1 || !expr2 || !value2) { return false; } if (!isSameExpression(cpp, true, expr1, expr2, library, pure, followVar, errors)) return false; const ValueFlow::Value &rhsValue1 = value1->values().front(); const ValueFlow::Value &rhsValue2 = value2->values().front(); if (op1 == "<" || op1 == "<=") return (op2 == "==" || op2 == ">" || op2 == ">=") && (rhsValue1.intvalue < rhsValue2.intvalue); else if (op1 == ">=" || op1 == ">") return (op2 == "==" || op2 == "<" || op2 == "<=") && (rhsValue1.intvalue > rhsValue2.intvalue); return false; } // is condition opposite? return ((comp1 == "==" && comp2 == "!=") || (comp1 == "!=" && comp2 == "==") || (comp1 == "<" && comp2 == ">=") || (comp1 == "<=" && comp2 == ">") || (comp1 == ">" && comp2 == "<=") || (comp1 == ">=" && comp2 == "<") || (!isNot && ((comp1 == "<" && comp2 == ">") || (comp1 == ">" && comp2 == "<") || (comp1 == "==" && (comp2 == "!=" || comp2 == ">" || comp2 == "<")) || ((comp1 == "!=" || comp1 == ">" || comp1 == "<") && comp2 == "==") ))); } bool isOppositeExpression(bool cpp, const Token * const tok1, const Token * const tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors) { if (!tok1 || !tok2) return false; if (isOppositeCond(true, cpp, tok1, tok2, library, pure, followVar, errors)) return true; if (tok1->isUnaryOp("-")) return isSameExpression(cpp, true, tok1->astOperand1(), tok2, library, pure, followVar, errors); if (tok2->isUnaryOp("-")) return isSameExpression(cpp, true, tok2->astOperand1(), tok1, library, pure, followVar, errors); return false; } bool isConstExpression(const Token *tok, const Library& library, bool pure, bool cpp) { if (!tok) return true; if (tok->isName() && tok->next()->str() == "(") { if (!tok->function() && !Token::Match(tok->previous(), ".|::") && !library.isFunctionConst(tok->str(), pure)) return false; else if (tok->function() && !tok->function()->isConst()) return false; } if (tok->tokType() == Token::eIncDecOp) return false; if (tok->isAssignmentOp()) return false; if (isLikelyStreamRead(cpp, tok)) return false; // bailout when we see ({..}) if (tok->str() == "{") return false; return isConstExpression(tok->astOperand1(), library, pure, cpp) && isConstExpression(tok->astOperand2(), library, pure, cpp); } bool isWithoutSideEffects(bool cpp, const Token* tok) { if (!cpp) return true; while (tok && tok->astOperand2() && tok->astOperand2()->str() != "(") tok = tok->astOperand2(); if (tok && tok->varId()) { const Variable* var = tok->variable(); return var && (!var->isClass() || var->isPointer() || var->isStlType()); } return true; } bool isUniqueExpression(const Token* tok) { if (!tok) return true; if (tok->function()) { const Function * fun = tok->function(); const Scope * scope = fun->nestedIn; if (!scope) return true; const std::string returnType = fun->retType ? fun->retType->name() : fun->retDef->stringifyList(fun->tokenDef); for (const Function& f:scope->functionList) { if (f.type != Function::eFunction) continue; const std::string freturnType = f.retType ? f.retType->name() : f.retDef->stringifyList(f.tokenDef); if (f.argumentList.size() == fun->argumentList.size() && returnType == freturnType && f.name() != fun->name()) { return false; } } } else if (tok->variable()) { const Variable * var = tok->variable(); const Scope * scope = var->scope(); if (!scope) return true; const Type * varType = var->type(); // Iterate over the variables in scope and the parameters of the function if possible const Function * fun = scope->function; const std::list* setOfVars[] = {&scope->varlist, fun ? &fun->argumentList : nullptr}; for (const std::list* vars:setOfVars) { if (!vars) continue; bool other = std::any_of(vars->cbegin(), vars->cend(), [=](const Variable &v) { if (varType) return v.type() && v.type()->name() == varType->name() && v.name() != var->name(); return v.isFloatingType() == var->isFloatingType() && v.isEnumType() == var->isEnumType() && v.isClass() == var->isClass() && v.isArray() == var->isArray() && v.isPointer() == var->isPointer() && v.name() != var->name(); }); if (other) return false; } } else if (!isUniqueExpression(tok->astOperand1())) { return false; } return isUniqueExpression(tok->astOperand2()); } static bool isEscaped(const Token* tok, bool functionsScope, const Library* library) { if (library && library->isnoreturn(tok)) return true; if (functionsScope) return Token::simpleMatch(tok, "throw"); else return Token::Match(tok, "return|throw"); } static bool isEscapedOrJump(const Token* tok, bool functionsScope, const Library* library) { if (library && library->isnoreturn(tok)) return true; if (functionsScope) return Token::simpleMatch(tok, "throw"); else return Token::Match(tok, "return|goto|throw|continue|break"); } bool isEscapeFunction(const Token* ftok, const Library* library) { if (!Token::Match(ftok, "%name% (")) return false; const Function* function = ftok->function(); if (function) { if (function->isEscapeFunction()) return true; if (function->isAttributeNoreturn()) return true; } else if (library) { if (library->isnoreturn(ftok)) return true; } return false; } static bool hasNoreturnFunction(const Token* tok, const Library* library, const Token** unknownFunc) { if (!tok) return false; const Token* ftok = tok->str() == "(" ? tok->previous() : nullptr; while (Token::simpleMatch(ftok, "(")) ftok = ftok->astOperand1(); if (ftok) { const Function * function = ftok->function(); if (function) { if (function->isEscapeFunction()) return true; if (function->isAttributeNoreturn()) return true; } else if (library && library->isnoreturn(ftok)) { return true; } else if (Token::Match(ftok, "exit|abort")) { return true; } if (unknownFunc && !function && library && library->functions.count(library->getFunctionName(ftok)) == 0) *unknownFunc = ftok; return false; } else if (tok->isConstOp()) { return hasNoreturnFunction(tok->astOperand1(), library, unknownFunc) || hasNoreturnFunction(tok->astOperand2(), library, unknownFunc); } return false; } bool isReturnScope(const Token* const endToken, const Library* library, const Token** unknownFunc, bool functionScope) { if (!endToken || endToken->str() != "}") return false; const Token *prev = endToken->previous(); while (prev && Token::simpleMatch(prev->previous(), "; ;")) prev = prev->previous(); if (prev && Token::simpleMatch(prev->previous(), "} ;")) prev = prev->previous(); if (Token::simpleMatch(prev, "}")) { if (Token::simpleMatch(prev->link()->tokAt(-2), "} else {")) return isReturnScope(prev, library, unknownFunc, functionScope) && isReturnScope(prev->link()->tokAt(-2), library, unknownFunc, functionScope); if (Token::simpleMatch(prev->link()->previous(), ") {") && Token::simpleMatch(prev->link()->linkAt(-1)->previous(), "switch (") && !Token::findsimplematch(prev->link(), "break", prev)) { return true; } if (isEscaped(prev->link()->astTop(), functionScope, library)) return true; if (Token::Match(prev->link()->previous(), "[;{}] {")) return isReturnScope(prev, library, unknownFunc, functionScope); } else if (Token::simpleMatch(prev, ";")) { if (prev->tokAt(-2) && hasNoreturnFunction(prev->tokAt(-2)->astTop(), library, unknownFunc)) return true; // Unknown symbol if (Token::Match(prev->tokAt(-2), ";|}|{ %name% ;") && prev->previous()->isIncompleteVar()) { if (unknownFunc) *unknownFunc = prev->previous(); return false; } if (Token::simpleMatch(prev->previous(), ") ;") && prev->previous()->link() && isEscaped(prev->previous()->link()->astTop(), functionScope, library)) return true; if (isEscaped(prev->previous()->astTop(), functionScope, library)) return true; // return/goto statement prev = prev->previous(); while (prev && !Token::Match(prev, ";|{|}") && !isEscapedOrJump(prev, functionScope, library)) prev = prev->previous(); return prev && prev->isName(); } return false; } bool isVariableChangedByFunctionCall(const Token *tok, int indirect, nonneg int varid, const Settings *settings, bool *inconclusive) { if (!tok) return false; if (tok->varId() == varid) return isVariableChangedByFunctionCall(tok, indirect, settings, inconclusive); return isVariableChangedByFunctionCall(tok->astOperand1(), indirect, varid, settings, inconclusive) || isVariableChangedByFunctionCall(tok->astOperand2(), indirect, varid, settings, inconclusive); } bool isScopeBracket(const Token* tok) { if (!Token::Match(tok, "{|}")) return false; if (!tok->scope()) return false; if (tok->str() == "{") return tok->scope()->bodyStart == tok; if (tok->str() == "}") return tok->scope()->bodyEnd == tok; return false; } const Token * getTokenArgumentFunction(const Token * tok, int& argn) { argn = -1; { const Token *parent = tok->astParent(); if (parent && parent->isUnaryOp("&")) parent = parent->astParent(); while (parent && parent->isCast()) parent = parent->astParent(); // passing variable to subfunction? if (Token::Match(parent, "[(,{]")) ; else if (Token::simpleMatch(parent, ":")) { while (Token::Match(parent, "[?:]")) parent = parent->astParent(); while (Token::simpleMatch(parent, ",")) parent = parent->astParent(); if (!parent || parent->str() != "(") return nullptr; } else return nullptr; } const Token* argtok = tok; while (argtok && argtok->astParent() && (!Token::Match(argtok->astParent(), ",|(|{") || argtok->astParent()->isCast())) { argtok = argtok->astParent(); } if (!argtok) return nullptr; if (Token::simpleMatch(argtok, ",")) argtok = argtok->astOperand1(); if (Token::simpleMatch(argtok, "(") && argtok->astOperand2()) argtok = argtok->astOperand2(); tok = argtok; while (Token::Match(tok->astParent(), ",|(|{")) { tok = tok->astParent(); if (Token::Match(tok, "(|{")) break; } std::vector args = getArguments(tok); auto it = std::find(args.begin(), args.end(), argtok); if (it != args.end()) argn = std::distance(args.begin(), it); if (argn == -1) return nullptr; if (!Token::Match(tok, "{|(")) return nullptr; tok = tok->astOperand1(); while (Token::simpleMatch(tok, ".")) tok = tok->astOperand2(); while (Token::simpleMatch(tok, "::")) { tok = tok->astOperand2(); if (Token::simpleMatch(tok, "<") && tok->link()) tok = tok->astOperand1(); } if (tok && tok->link() && tok->str() == ">") tok = tok->link()->previous(); if (!Token::Match(tok, "%name%|(|{")) return nullptr; return tok; } static const Variable* getArgumentVar(const Token* tok, int argnr) { if (!tok) return nullptr; if (tok->function()) return tok->function()->getArgumentVar(argnr); if (Token::Match(tok->previous(), "%type% (|{") || tok->variable()) { const Type* type = Token::typeOf(tok); if (!type) return nullptr; const Scope* typeScope = type->classScope; if (!typeScope) return nullptr; const int argCount = numberOfArguments(tok); for (const Function &function : typeScope->functionList) { if (function.isConstructor()) continue; if (function.argCount() < argCount) continue; if (!Token::simpleMatch(function.token, "operator()")) continue; return function.getArgumentVar(argnr); } } return nullptr; } static bool isCPPCastKeyword(const Token* tok) { if (!tok) return false; return endsWith(tok->str(), "_cast", 5); } bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Settings *settings, bool *inconclusive) { if (!tok) return false; if (Token::simpleMatch(tok, ",")) return false; const Token * const tok1 = tok; // address of variable const bool addressOf = tok->astParent() && tok->astParent()->isUnaryOp("&"); int argnr; tok = getTokenArgumentFunction(tok, argnr); if (!tok) return false; // not a function => variable not changed if (tok->isKeyword() && !isCPPCastKeyword(tok)) return false; const Token * parenTok = tok->next(); if (Token::simpleMatch(parenTok, "<") && parenTok->link()) parenTok = parenTok->link()->next(); const bool possiblyPassedByReference = (parenTok->next() == tok1 || Token::Match(tok1->previous(), ", %name% [,)}]")); // Constructor call if (tok->variable() && tok->variable()->nameToken() == tok) { // Find constructor.. const int argCount = numberOfArguments(tok); const Scope *typeScope = tok->variable()->typeScope(); if (typeScope) { for (const Function &function : typeScope->functionList) { if (!function.isConstructor() || function.argCount() < argCount) continue; const Variable *arg = function.getArgumentVar(argnr); if (arg && arg->isReference() && !arg->isConst()) return true; } return false; } if (inconclusive) *inconclusive = true; return false; } if (!tok->function() && !tok->variable() && Token::Match(tok, "%name%")) { // Check if direction (in, out, inout) is specified in the library configuration and use that if (!addressOf && settings) { const Library::ArgumentChecks::Direction argDirection = settings->library.getArgDirection(tok, 1 + argnr); if (argDirection == Library::ArgumentChecks::Direction::DIR_IN) return false; else if (argDirection == Library::ArgumentChecks::Direction::DIR_OUT || argDirection == Library::ArgumentChecks::Direction::DIR_INOUT) { // With out or inout the direction of the content is specified, not a pointer itself, so ignore pointers for now const ValueType * const valueType = tok1->valueType(); if (valueType && valueType->pointer == indirect) { return true; } } } // if the library says 0 is invalid // => it is assumed that parameter is an in parameter (TODO: this is a bad heuristic) if (!addressOf && settings && settings->library.isnullargbad(tok, 1+argnr)) return false; // possible pass-by-reference => inconclusive if (possiblyPassedByReference) { if (inconclusive != nullptr) *inconclusive = true; return false; } // Safe guess: Assume that parameter is changed by function call return true; } const Variable *arg = getArgumentVar(tok, argnr); if (!arg) { if (inconclusive) *inconclusive = true; return false; } if (addressOf || (indirect > 0 && arg->isPointer())) { if (!arg->isConst()) return true; // If const is applied to the pointer, then the value can still be modified if (Token::simpleMatch(arg->typeEndToken(), "* const")) return true; } return !arg->isConst() && arg->isReference(); } bool isVariableChanged(const Token *tok, int indirect, const Settings *settings, bool cpp, int depth) { if (!tok) return false; const Token *tok2 = tok; int derefs = 0; while (Token::simpleMatch(tok2->astParent(), "*") || (Token::simpleMatch(tok2->astParent(), ".") && !Token::simpleMatch(tok2->astParent()->astParent(), "(")) || (Token::simpleMatch(tok2->astParent(), "[") && tok2 == tok2->astParent()->astOperand1())) { if (Token::simpleMatch(tok2->astParent(), "*") || tok2->astParent()->originalName() == "->") derefs++; if (derefs > indirect) break; tok2 = tok2->astParent(); } while (Token::simpleMatch(tok2->astParent(), "?") || (Token::simpleMatch(tok2->astParent(), ":") && Token::simpleMatch(tok2->astParent()->astParent(), "?"))) tok2 = tok2->astParent(); if (Token::Match(tok2->astParent(), "++|--")) return true; if (tok2->astParent() && tok2->astParent()->isAssignmentOp()) { if (tok2 == tok2->astParent()->astOperand1()) return true; // Check if assigning to a non-const lvalue const Variable * var = getLHSVariable(tok2->astParent()); if (var && var->isReference() && !var->isConst() && var->nameToken() && var->nameToken()->next() == tok2->astParent()) { if (!var->isLocal() || isVariableChanged(var, settings, cpp, depth - 1)) return true; } } if (cpp && Token::simpleMatch(tok2->astParent(), ">>") && tok2->astParent()->astOperand2() == tok2 && isLikelyStreamRead(cpp, tok2->astParent())) return true; if (isLikelyStream(cpp, tok2)) return true; // Member function call if (tok->variable() && Token::Match(tok2->astParent(), ". %name%") && isFunctionCall(tok2->astParent()->next()) && tok2->astParent()->astOperand1() == tok2) { const Variable * var = tok->variable(); bool isConst = var && var->isConst(); if (!isConst) { const ValueType * valueType = var->valueType(); isConst = (valueType && valueType->pointer == 1 && valueType->constness == 1); } const Token *ftok = tok->tokAt(2); const Function * fun = ftok->function(); if (!isConst && (!fun || !fun->isConst())) return true; else return false; } const Token *ftok = tok2; while (ftok && (!Token::Match(ftok, "[({]") || ftok->isCast())) ftok = ftok->astParent(); if (ftok && Token::Match(ftok->link(), ")|} !!{")) { const Token * ptok = tok2; while (Token::Match(ptok->astParent(), ".|::|[")) ptok = ptok->astParent(); bool inconclusive = false; bool isChanged = isVariableChangedByFunctionCall(ptok, indirect, settings, &inconclusive); isChanged |= inconclusive; if (isChanged) return true; } const Token *parent = tok2->astParent(); while (Token::Match(parent, ".|::")) parent = parent->astParent(); if (parent && parent->tokType() == Token::eIncDecOp) return true; if (Token::simpleMatch(tok2->astParent(), ":") && tok2->astParent()->astParent() && Token::simpleMatch(tok2->astParent()->astParent()->previous(), "for (")) { const Token * varTok = tok2->astParent()->previous(); if (!varTok) return false; const Variable * loopVar = varTok->variable(); if (!loopVar) return false; if (!loopVar->isConst() && loopVar->isReference() && isVariableChanged(loopVar, settings, cpp, depth - 1)) return true; return false; } return false; } bool isVariableChanged(const Token *start, const Token *end, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth) { return findVariableChanged(start, end, 0, varid, globalvar, settings, cpp, depth) != nullptr; } bool isVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth) { return findVariableChanged(start, end, indirect, varid, globalvar, settings, cpp, depth) != nullptr; } Token* findVariableChanged(Token *start, const Token *end, int indirect, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth) { if (!precedes(start, end)) return nullptr; if (depth < 0) return start; for (Token *tok = start; tok != end; tok = tok->next()) { if (tok->varId() != varid) { if (globalvar && Token::Match(tok, "%name% (")) // TODO: Is global variable really changed by function call? return tok; continue; } if (isVariableChanged(tok, indirect, settings, cpp, depth)) return tok; } return nullptr; } const Token* findVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth) { return findVariableChanged(const_cast(start), end, indirect, varid, globalvar, settings, cpp, depth); } bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp, int depth) { if (!var) return false; if (!var->scope()) return false; const Token * start = var->declEndToken(); if (!start) return false; if (Token::Match(start, "; %varid% =", var->declarationId())) start = start->tokAt(2); return isVariableChanged(start->next(), var->scope()->bodyEnd, var->declarationId(), var->isGlobal(), settings, cpp, depth); } bool isVariablesChanged(const Token* start, const Token* end, int indirect, std::vector vars, const Settings* settings, bool cpp) { std::set varids; std::transform(vars.begin(), vars.end(), std::inserter(varids, varids.begin()), [](const Variable* var) { return var->declarationId(); }); const bool globalvar = std::any_of(vars.begin(), vars.end(), [](const Variable* var) { return var->isGlobal(); }); for (const Token* tok = start; tok != end; tok = tok->next()) { if (tok->varId() == 0 || varids.count(tok->varId()) == 0) { if (globalvar && Token::Match(tok, "%name% (")) // TODO: Is global variable really changed by function call? return true; continue; } if (isVariableChanged(tok, indirect, settings, cpp)) return true; } return false; } bool isThisChanged(const Token* start, const Token* end, int indirect, const Settings* settings, bool cpp) { for (const Token* tok = start; tok != end; tok = tok->next()) { if (!exprDependsOnThis(tok)) continue; if (Token::Match(tok->previous(), "%name% (")) { if (tok->previous()->function()) { if (!tok->previous()->function()->isConst()) return true; else continue; } else if (!tok->previous()->isKeyword()) { return true; } } if (isVariableChanged(tok, indirect, settings, cpp)) return true; } return false; } int numberOfArguments(const Token *start) { int arguments=0; const Token* const openBracket = start->next(); if (openBracket && openBracket->str()=="(" && openBracket->next() && openBracket->next()->str()!=")") { const Token* argument=openBracket->next(); while (argument) { ++arguments; argument = argument->nextArgument(); } } return arguments; } std::vector getArguments(const Token *ftok) { const Token* tok = ftok; if (Token::Match(tok, "%name% (|{")) tok = ftok->next(); if (!Token::Match(tok, "(|{|[")) return std::vector {}; const Token *startTok = tok->astOperand2(); if (!startTok && tok->next() != tok->link()) startTok = tok->astOperand1(); return astFlatten(startTok, ","); } const Token *findLambdaStartToken(const Token *last) { if (!last || last->str() != "}") return nullptr; const Token* tok = last->link(); if (Token::simpleMatch(tok->astParent(), "(")) tok = tok->astParent(); if (Token::simpleMatch(tok->astParent(), "[")) return tok->astParent(); return nullptr; } template T* findLambdaEndTokenGeneric(T* first) { if (!first || first->str() != "[") return nullptr; if (!Token::Match(first->link(), "] (|{")) return nullptr; if (first->astOperand1() != first->link()->next()) return nullptr; const Token * tok = first; if (tok->astOperand1() && tok->astOperand1()->str() == "(") tok = tok->astOperand1(); if (tok->astOperand1() && tok->astOperand1()->str() == "{") return tok->astOperand1()->link(); return nullptr; } const Token* findLambdaEndToken(const Token* first) { return findLambdaEndTokenGeneric(first); } Token* findLambdaEndToken(Token* first) { return findLambdaEndTokenGeneric(first); } bool isLikelyStream(bool cpp, const Token *stream) { if (!cpp) return false; if (!stream) return false; if (!Token::Match(stream->astParent(), "&|<<|>>") || !stream->astParent()->isBinaryOp()) return false; if (stream->astParent()->astOperand1() != stream) return false; return !astIsIntegral(stream, false); } bool isLikelyStreamRead(bool cpp, const Token *op) { if (!cpp) return false; if (!Token::Match(op, "&|>>") || !op->isBinaryOp()) return false; if (!Token::Match(op->astOperand2(), "%name%|.|*|[") && op->str() != op->astOperand2()->str()) return false; const Token *parent = op; while (parent->astParent() && parent->astParent()->str() == op->str()) parent = parent->astParent(); if (parent->astParent() && !Token::Match(parent->astParent(), "%oror%|&&|(|,|.|!")) return false; if (op->str() == "&" && parent->astParent()) return false; if (!parent->astOperand1() || !parent->astOperand2()) return false; return (!parent->astOperand1()->valueType() || !parent->astOperand1()->valueType()->isIntegral()); } bool isCPPCast(const Token* tok) { return tok && Token::simpleMatch(tok->previous(), "> (") && tok->astOperand2() && tok->astOperand1() && isCPPCastKeyword(tok->astOperand1()); } bool isConstVarExpression(const Token *tok, const char* skipMatch) { if (!tok) return false; if (skipMatch && Token::Match(tok, skipMatch)) return false; if (Token::simpleMatch(tok->previous(), "sizeof (")) return true; if (Token::Match(tok->previous(), "%name% (")) { if (Token::simpleMatch(tok->astOperand1(), ".") && !isConstVarExpression(tok->astOperand1(), skipMatch)) return false; std::vector args = getArguments(tok); return std::all_of(args.begin(), args.end(), [&](const Token* t) { return isConstVarExpression(t, skipMatch); }); } if (isCPPCast(tok)) { return isConstVarExpression(tok->astOperand2(), skipMatch); } if (Token::Match(tok, "( %type%")) return isConstVarExpression(tok->astOperand1(), skipMatch); if (tok->str() == "::" && tok->hasKnownValue()) return isConstVarExpression(tok->astOperand2(), skipMatch); if (Token::Match(tok, "%cop%|[|.")) { if (tok->astOperand1() && !isConstVarExpression(tok->astOperand1(), skipMatch)) return false; if (tok->astOperand2() && !isConstVarExpression(tok->astOperand2(), skipMatch)) return false; return true; } if (Token::Match(tok, "%bool%|%num%|%str%|%char%|nullptr|NULL")) return true; if (tok->isEnumerator()) return true; if (tok->variable()) return tok->variable()->isConst() && tok->variable()->nameToken() && tok->variable()->nameToken()->hasKnownValue(); return false; } static void getLHSVariablesRecursive(std::vector& vars, const Token* tok) { if (!tok) return; if (vars.empty() && Token::Match(tok, "*|&|&&|[")) { getLHSVariablesRecursive(vars, tok->astOperand1()); if (!vars.empty() || Token::simpleMatch(tok, "[")) return; getLHSVariablesRecursive(vars, tok->astOperand2()); } else if (Token::Match(tok->previous(), "this . %var%")) { getLHSVariablesRecursive(vars, tok->next()); } else if (Token::simpleMatch(tok, ".")) { getLHSVariablesRecursive(vars, tok->astOperand1()); getLHSVariablesRecursive(vars, tok->astOperand2()); } else if (tok->variable()) { vars.push_back(tok->variable()); } } std::vector getLHSVariables(const Token* tok) { std::vector result; if (!Token::Match(tok, "%assign%")) return result; if (!tok->astOperand1()) return result; if (tok->astOperand1()->varId() > 0 && tok->astOperand1()->variable()) return {tok->astOperand1()->variable()}; getLHSVariablesRecursive(result, tok->astOperand1()); return result; } static const Variable *getLHSVariableRecursive(const Token *tok) { if (!tok) return nullptr; if (Token::Match(tok, "*|&|&&|[")) { const Variable *var = getLHSVariableRecursive(tok->astOperand1()); if (var || Token::simpleMatch(tok, "[")) return var; return getLHSVariableRecursive(tok->astOperand2()); } if (Token::Match(tok->previous(), "this . %var%")) return tok->next()->variable(); return tok->variable(); } const Variable *getLHSVariable(const Token *tok) { if (!Token::Match(tok, "%assign%")) return nullptr; if (!tok->astOperand1()) return nullptr; if (tok->astOperand1()->varId() > 0 && tok->astOperand1()->variable()) return tok->astOperand1()->variable(); return getLHSVariableRecursive(tok->astOperand1()); } static bool nonLocal(const Variable* var, bool deref) { return !var || (!var->isLocal() && !var->isArgument()) || (deref && var->isArgument() && var->isPointer()) || var->isStatic() || var->isReference() || var->isExtern(); } static bool hasGccCompoundStatement(const Token *tok) { if (!tok) return false; if (tok->str() == "{" && Token::simpleMatch(tok->previous(), "( {")) return true; return hasGccCompoundStatement(tok->astOperand1()) || hasGccCompoundStatement(tok->astOperand2()); } static bool hasFunctionCall(const Token *tok) { if (!tok) return false; if (Token::Match(tok, "%name% (")) // todo, const/pure function? return true; return hasFunctionCall(tok->astOperand1()) || hasFunctionCall(tok->astOperand2()); } static bool isUnchanged(const Token *startToken, const Token *endToken, const std::set &exprVarIds, bool local) { for (const Token *tok = startToken; tok != endToken; tok = tok->next()) { if (!local && Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) // TODO: this is a quick bailout return false; if (tok->varId() <= 0 || exprVarIds.find(tok->varId()) == exprVarIds.end()) continue; const Token *parent = tok; while (parent->astParent() && !parent->astParent()->isAssignmentOp() && parent->astParent()->tokType() != Token::Type::eIncDecOp) { if (parent->str() == "," || parent->isUnaryOp("&")) // TODO: This is a quick bailout return false; parent = parent->astParent(); } if (parent->astParent()) { if (parent->astParent()->tokType() == Token::Type::eIncDecOp) return false; else if (parent->astParent()->isAssignmentOp() && parent == parent->astParent()->astOperand1()) return false; } } return true; } bool isNullOperand(const Token *expr) { if (!expr) return false; if (Token::Match(expr, "static_cast|const_cast|dynamic_cast|reinterpret_cast <")) expr = expr->astParent(); else if (!expr->isCast()) return Token::Match(expr, "NULL|nullptr"); if (expr->valueType() && expr->valueType()->pointer == 0) return false; const Token *castOp = expr->astOperand2() ? expr->astOperand2() : expr->astOperand1(); return Token::Match(castOp, "NULL|nullptr") || (MathLib::isInt(castOp->str()) && MathLib::isNullValue(castOp->str())); } bool isGlobalData(const Token *expr, bool cpp) { bool globalData = false; visitAstNodes(expr, [&](const Token *tok) { if (tok->varId() && !tok->variable()) { // Bailout, this is probably global globalData = true; return ChildrenToVisit::none; } if (tok->originalName() == "->") { // TODO check if pointer points at local data globalData = true; return ChildrenToVisit::none; } else if (Token::Match(tok, "[*[]") && tok->astOperand1() && tok->astOperand1()->variable()) { // TODO check if pointer points at local data const Variable *lhsvar = tok->astOperand1()->variable(); const ValueType *lhstype = tok->astOperand1()->valueType(); if (lhsvar->isPointer()) { globalData = true; return ChildrenToVisit::none; } else if (lhsvar->isArgument() && lhsvar->isArray()) { globalData = true; return ChildrenToVisit::none; } else if (lhsvar->isArgument() && (!lhstype || (lhstype->type <= ValueType::Type::VOID && !lhstype->container))) { globalData = true; return ChildrenToVisit::none; } } if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".") { globalData = true; return ChildrenToVisit::none; } if (tok->variable()) { // TODO : Check references if (tok->variable()->isReference() && tok != tok->variable()->nameToken()) { globalData = true; return ChildrenToVisit::none; } if (tok->variable()->isExtern()) { globalData = true; return ChildrenToVisit::none; } if (tok->previous()->str() != "." && !tok->variable()->isLocal() && !tok->variable()->isArgument()) { globalData = true; return ChildrenToVisit::none; } if (tok->variable()->isArgument() && tok->variable()->isPointer() && tok != expr) { globalData = true; return ChildrenToVisit::none; } if (tok->variable()->isPointerArray()) { globalData = true; return ChildrenToVisit::none; } } // Unknown argument type => it might be some reference type.. if (cpp && tok->str() == "." && tok->astOperand1() && tok->astOperand1()->variable() && !tok->astOperand1()->valueType()) { globalData = true; return ChildrenToVisit::none; } if (Token::Match(tok, ".|[")) return ChildrenToVisit::op1; return ChildrenToVisit::op1_and_op2; }); return globalData; } struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set &exprVarIds, bool local, bool inInnerClass, int depth) { // Parse the given tokens if (++depth > 1000) return Result(Result::Type::BAILOUT); for (const Token* tok = startToken; precedes(tok, endToken); tok = tok->next()) { if (Token::simpleMatch(tok, "try {")) { // TODO: handle try return Result(Result::Type::BAILOUT); } if (Token::simpleMatch(tok, "break ;")) { return Result(Result::Type::BREAK, tok); } if (Token::simpleMatch(tok, "goto")) return Result(Result::Type::BAILOUT); if (!inInnerClass && tok->str() == "{" && tok->scope()->isClassOrStruct()) { // skip returns from local class definition FwdAnalysis::Result result = checkRecursive(expr, tok, tok->link(), exprVarIds, local, true, depth); if (result.type != Result::Type::NONE) return result; tok=tok->link(); } if (tok->str() == "continue") // TODO return Result(Result::Type::BAILOUT); if (const Token *lambdaEndToken = findLambdaEndToken(tok)) { tok = lambdaEndToken; const Result lambdaResult = checkRecursive(expr, lambdaEndToken->link()->next(), lambdaEndToken, exprVarIds, local, inInnerClass, depth); if (lambdaResult.type == Result::Type::READ || lambdaResult.type == Result::Type::BAILOUT) return lambdaResult; } if (Token::Match(tok, "return|throw")) { // TODO: Handle these better // Is expr variable used in expression? const Token* opTok = tok->astOperand1(); if (!opTok) opTok = tok->next(); std::pair startEndTokens = opTok->findExpressionStartEndTokens(); FwdAnalysis::Result result = checkRecursive(expr, startEndTokens.first, startEndTokens.second->next(), exprVarIds, local, true, depth); if (result.type != Result::Type::NONE) return result; // #9167: if the return is inside an inner class, it does not tell us anything if (!inInnerClass) { if (!local && mWhat == What::Reassign) return Result(Result::Type::BAILOUT); return Result(Result::Type::RETURN); } } if (tok->str() == "}") { // Known value => possible value if (tok->scope() == expr->scope()) mValueFlowKnown = false; Scope::ScopeType scopeType = tok->scope()->type; if (scopeType == Scope::eWhile || scopeType == Scope::eFor || scopeType == Scope::eDo) { // check condition const Token *conditionStart = nullptr; const Token *conditionEnd = nullptr; if (Token::simpleMatch(tok->link()->previous(), ") {")) { conditionEnd = tok->link()->previous(); conditionStart = conditionEnd->link(); } else if (Token::simpleMatch(tok->link()->previous(), "do {") && Token::simpleMatch(tok, "} while (")) { conditionStart = tok->tokAt(2); conditionEnd = conditionStart->link(); } if (conditionStart && conditionEnd) { bool used = false; for (const Token *condTok = conditionStart; condTok != conditionEnd; condTok = condTok->next()) { if (exprVarIds.find(condTok->varId()) != exprVarIds.end()) { used = true; break; } } if (used) return Result(Result::Type::BAILOUT); } // check loop body again.. const struct FwdAnalysis::Result &result = checkRecursive(expr, tok->link(), tok, exprVarIds, local, inInnerClass, depth); if (result.type == Result::Type::BAILOUT || result.type == Result::Type::READ) return result; } } if (Token::simpleMatch(tok, "else {")) tok = tok->linkAt(1); if (Token::simpleMatch(tok, "asm (")) return Result(Result::Type::BAILOUT); if (mWhat == What::ValueFlow && (Token::Match(tok, "while|for (") || Token::simpleMatch(tok, "do {"))) { const Token *bodyStart = nullptr; const Token *conditionStart = nullptr; if (Token::simpleMatch(tok, "do {")) { bodyStart = tok->next(); if (Token::simpleMatch(bodyStart->link(), "} while (")) conditionStart = bodyStart->link()->tokAt(2); } else { conditionStart = tok->next(); if (Token::simpleMatch(conditionStart->link(), ") {")) bodyStart = conditionStart->link()->next(); } if (!bodyStart || !conditionStart) return Result(Result::Type::BAILOUT); // Is expr changed in condition? if (!isUnchanged(conditionStart, conditionStart->link(), exprVarIds, local)) return Result(Result::Type::BAILOUT); // Is expr changed in loop body? if (!isUnchanged(bodyStart, bodyStart->link(), exprVarIds, local)) return Result(Result::Type::BAILOUT); } if (mWhat == What::ValueFlow && Token::simpleMatch(tok, "if (") && Token::simpleMatch(tok->linkAt(1), ") {")) { const Token *bodyStart = tok->linkAt(1)->next(); const Token *conditionStart = tok->next(); const Token *condTok = conditionStart->astOperand2(); if (condTok->hasKnownIntValue()) { bool cond = condTok->values().front().intvalue; if (cond) { FwdAnalysis::Result result = checkRecursive(expr, bodyStart, bodyStart->link(), exprVarIds, local, true, depth); if (result.type != Result::Type::NONE) return result; } else if (Token::simpleMatch(bodyStart->link(), "} else {")) { bodyStart = bodyStart->link()->tokAt(2); FwdAnalysis::Result result = checkRecursive(expr, bodyStart, bodyStart->link(), exprVarIds, local, true, depth); if (result.type != Result::Type::NONE) return result; } } tok = bodyStart->link(); if (isReturnScope(tok, &mLibrary)) return Result(Result::Type::BAILOUT); if (Token::simpleMatch(tok, "} else {")) tok = tok->linkAt(2); if (!tok) return Result(Result::Type::BAILOUT); // Is expr changed in condition? if (!isUnchanged(conditionStart, conditionStart->link(), exprVarIds, local)) return Result(Result::Type::BAILOUT); // Is expr changed in condition body? if (!isUnchanged(bodyStart, bodyStart->link(), exprVarIds, local)) return Result(Result::Type::BAILOUT); } if (!local && Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) { // TODO: this is a quick bailout return Result(Result::Type::BAILOUT); } if (mWhat == What::Reassign && Token::simpleMatch(tok, ";") && Token::simpleMatch(tok->astParent(), ";") && Token::simpleMatch(tok->astParent()->astParent(), "(") && Token::simpleMatch(tok->astParent()->astParent()->previous(), "for (") && !isUnchanged(tok, tok->astParent()->astParent()->link(), exprVarIds, local)) // TODO: This is a quick bailout to avoid FP #9420, there are false negatives (TODO_ASSERT_EQUALS) return Result(Result::Type::BAILOUT); if (expr->isName() && Token::Match(tok, "%name% (") && tok->str().find("<") != std::string::npos && tok->str().find(expr->str()) != std::string::npos) return Result(Result::Type::BAILOUT); if (exprVarIds.find(tok->varId()) != exprVarIds.end()) { const Token *parent = tok; bool other = false; bool same = tok->astParent() && isSameExpression(mCpp, false, expr, tok, mLibrary, true, false, nullptr); while (!same && Token::Match(parent->astParent(), "*|.|::|[|(|%cop%")) { parent = parent->astParent(); if (parent && isSameExpression(mCpp, false, expr, parent, mLibrary, true, false, nullptr)) { same = true; if (mWhat == What::ValueFlow) { KnownAndToken v; v.known = mValueFlowKnown; v.token = parent; mValueFlow.push_back(v); } } if (Token::Match(parent, ". %var%") && parent->next()->varId() && exprVarIds.find(parent->next()->varId()) == exprVarIds.end()) { other = true; break; } } if (mWhat != What::ValueFlow && same && Token::simpleMatch(parent->astParent(), "[") && parent == parent->astParent()->astOperand2()) { return Result(Result::Type::READ); } if (other) continue; if (Token::simpleMatch(parent->astParent(), "=") && parent == parent->astParent()->astOperand1()) { if (!local && hasFunctionCall(parent->astParent()->astOperand2())) { // TODO: this is a quick bailout return Result(Result::Type::BAILOUT); } if (hasOperand(parent->astParent()->astOperand2(), expr)) { if (mWhat == What::Reassign) return Result(Result::Type::READ); continue; } // ({ .. }) if (hasGccCompoundStatement(parent->astParent()->astOperand2())) return Result(Result::Type::BAILOUT); const bool reassign = isSameExpression(mCpp, false, expr, parent, mLibrary, false, false, nullptr); if (reassign) return Result(Result::Type::WRITE, parent->astParent()); return Result(Result::Type::READ); } else if (mWhat == What::Reassign && parent->valueType() && parent->valueType()->pointer && Token::Match(parent->astParent(), "%assign%") && parent == parent->astParent()->astOperand1()) { return Result(Result::Type::READ); } else if (Token::Match(parent->astParent(), "%assign%") && !parent->astParent()->astParent() && parent == parent->astParent()->astOperand1()) { if (mWhat == What::Reassign) return Result(Result::Type::BAILOUT, parent->astParent()); continue; } else { // TODO: this is a quick bailout return Result(Result::Type::BAILOUT, parent->astParent()); } } if (Token::Match(tok, ")|do {")) { if (tok->str() == ")" && Token::simpleMatch(tok->link()->previous(), "switch (")) // TODO: parse switch return Result(Result::Type::BAILOUT); const Result &result1 = checkRecursive(expr, tok->tokAt(2), tok->linkAt(1), exprVarIds, local, inInnerClass, depth); if (result1.type == Result::Type::READ || result1.type == Result::Type::BAILOUT) return result1; if (mWhat == What::ValueFlow && result1.type == Result::Type::WRITE) mValueFlowKnown = false; if (Token::simpleMatch(tok->linkAt(1), "} else {")) { const Token *elseStart = tok->linkAt(1)->tokAt(2); const Result &result2 = checkRecursive(expr, elseStart, elseStart->link(), exprVarIds, local, inInnerClass, depth); if (mWhat == What::ValueFlow && result2.type == Result::Type::WRITE) mValueFlowKnown = false; if (result2.type == Result::Type::READ || result2.type == Result::Type::BAILOUT) return result2; if (result1.type == Result::Type::WRITE && result2.type == Result::Type::WRITE) return result1; tok = elseStart->link(); } else { tok = tok->linkAt(1); } } } return Result(Result::Type::NONE); } static bool hasVolatileCastOrVar(const Token *expr) { bool ret = false; visitAstNodes(expr, [&ret](const Token *tok) { if (Token::simpleMatch(tok, "( volatile")) ret = true; else if (tok->variable() && tok->variable()->isVolatile()) ret = true; return ret ? ChildrenToVisit::none : ChildrenToVisit::op1_and_op2; }); return ret; } bool FwdAnalysis::isGlobalData(const Token *expr) const { return ::isGlobalData(expr, mCpp); } std::set FwdAnalysis::getExprVarIds(const Token* expr, bool* localOut, bool* unknownVarIdOut) const { // all variable ids in expr. std::set exprVarIds; bool local = true; bool unknownVarId = false; visitAstNodes(expr, [&](const Token *tok) { if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".") { // unknown variable unknownVarId = true; return ChildrenToVisit::none; } if (tok->varId() > 0) { exprVarIds.insert(tok->varId()); if (!Token::simpleMatch(tok->previous(), ".")) { const Variable *var = tok->variable(); if (var && var->isReference() && var->isLocal() && Token::Match(var->nameToken(), "%var% [=(]") && !isGlobalData(var->nameToken()->next()->astOperand2())) return ChildrenToVisit::none; const bool deref = tok->astParent() && (tok->astParent()->isUnaryOp("*") || (tok->astParent()->str() == "[" && tok == tok->astParent()->astOperand1())); local &= !nonLocal(tok->variable(), deref); } } return ChildrenToVisit::op1_and_op2; }); if (localOut) *localOut = local; if (unknownVarIdOut) *unknownVarIdOut = unknownVarId; return exprVarIds; } FwdAnalysis::Result FwdAnalysis::check(const Token* expr, const Token* startToken, const Token* endToken) { // all variable ids in expr. bool local = true; bool unknownVarId = false; std::set exprVarIds = getExprVarIds(expr, &local, &unknownVarId); if (unknownVarId) return Result(FwdAnalysis::Result::Type::BAILOUT); if (mWhat == What::Reassign && isGlobalData(expr)) local = false; // In unused values checking we do not want to check assignments to // global data. if (mWhat == What::UnusedValue && isGlobalData(expr)) return Result(FwdAnalysis::Result::Type::BAILOUT); Result result = checkRecursive(expr, startToken, endToken, exprVarIds, local, false); // Break => continue checking in outer scope while (mWhat!=What::ValueFlow && result.type == FwdAnalysis::Result::Type::BREAK) { const Scope *s = result.token->scope(); while (s->type == Scope::eIf) s = s->nestedIn; if (s->type != Scope::eSwitch && s->type != Scope::eWhile && s->type != Scope::eFor) break; result = checkRecursive(expr, s->bodyEnd->next(), endToken, exprVarIds, local, false); } return result; } bool FwdAnalysis::hasOperand(const Token *tok, const Token *lhs) const { if (!tok) return false; if (isSameExpression(mCpp, false, tok, lhs, mLibrary, false, false, nullptr)) return true; return hasOperand(tok->astOperand1(), lhs) || hasOperand(tok->astOperand2(), lhs); } const Token *FwdAnalysis::reassign(const Token *expr, const Token *startToken, const Token *endToken) { if (hasVolatileCastOrVar(expr)) return nullptr; mWhat = What::Reassign; Result result = check(expr, startToken, endToken); return result.type == FwdAnalysis::Result::Type::WRITE ? result.token : nullptr; } bool FwdAnalysis::unusedValue(const Token *expr, const Token *startToken, const Token *endToken) { if (isEscapedAlias(expr)) return false; if (hasVolatileCastOrVar(expr)) return false; mWhat = What::UnusedValue; Result result = check(expr, startToken, endToken); return (result.type == FwdAnalysis::Result::Type::NONE || result.type == FwdAnalysis::Result::Type::RETURN) && !possiblyAliased(expr, startToken); } std::vector FwdAnalysis::valueFlow(const Token *expr, const Token *startToken, const Token *endToken) { mWhat = What::ValueFlow; mValueFlowKnown = true; check(expr, startToken, endToken); return mValueFlow; } bool FwdAnalysis::possiblyAliased(const Token *expr, const Token *startToken) const { if (expr->isUnaryOp("*")) return true; const bool macro = false; const bool pure = false; const bool followVar = false; for (const Token *tok = startToken; tok; tok = tok->previous()) { if (tok->str() == "{" && tok->scope()->type == Scope::eFunction) break; if (Token::Match(tok, "%name% (") && !Token::Match(tok, "if|while|for")) { // Is argument passed by reference? const std::vector args = getArguments(tok); for (int argnr = 0; argnr < args.size(); ++argnr) { if (!Token::Match(args[argnr], "%name%|.|::")) continue; if (tok->function() && tok->function()->getArgumentVar(argnr) && !tok->function()->getArgumentVar(argnr)->isReference() && !tok->function()->isConst()) continue; for (const Token *subexpr = expr; subexpr; subexpr = subexpr->astOperand1()) { if (isSameExpression(mCpp, macro, subexpr, args[argnr], mLibrary, pure, followVar)) return true; } } continue; } const Token *addrOf = nullptr; if (Token::Match(tok, "& %name% =")) addrOf = tok->tokAt(2)->astOperand2(); else if (tok->isUnaryOp("&")) addrOf = tok->astOperand1(); else if (Token::simpleMatch(tok, "std :: ref (")) addrOf = tok->tokAt(3)->astOperand2(); else continue; for (const Token *subexpr = expr; subexpr; subexpr = subexpr->astOperand1()) { if (isSameExpression(mCpp, macro, subexpr, addrOf, mLibrary, pure, followVar)) return true; } } return false; } bool FwdAnalysis::isEscapedAlias(const Token* expr) { for (const Token *subexpr = expr; subexpr; subexpr = subexpr->astOperand1()) { for (const ValueFlow::Value &val : subexpr->values()) { if (!val.isLocalLifetimeValue()) continue; const Variable* var = val.tokvalue->variable(); if (!var) continue; if (!var->isLocal()) return true; if (var->isArgument()) return true; } } return false; }