From 1caa66d0759f6bd0851a40645afac8e8a7f84341 Mon Sep 17 00:00:00 2001 From: Aaron Ballman Date: Wed, 30 Oct 2019 13:35:20 -0400 Subject: [PATCH] Fix a false positive in misc-redundant-expression check Do not warn for redundant conditional expressions when the true and false branches are expanded from different macros even when they are defined by one another. Patch by Daniel Krupp. --- .../clang-tidy/misc/RedundantExpressionCheck.cpp | 67 +++++++++++++++++++--- .../checkers/misc-redundant-expression.cpp | 19 +++++- 2 files changed, 78 insertions(+), 8 deletions(-) diff --git a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp index e646ee9..e3e84b7 100644 --- a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp +++ b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp @@ -131,6 +131,20 @@ static bool areEquivalentExpr(const Expr *Left, const Expr *Right) { case Stmt::BinaryOperatorClass: return cast(Left)->getOpcode() == cast(Right)->getOpcode(); + case Stmt::UnaryExprOrTypeTraitExprClass: + const auto *LeftUnaryExpr = + cast(Left); + const auto *RightUnaryExpr = + cast(Right); + if (LeftUnaryExpr->isArgumentType() && RightUnaryExpr->isArgumentType()) + return LeftUnaryExpr->getArgumentType() == + RightUnaryExpr->getArgumentType(); + else if (!LeftUnaryExpr->isArgumentType() && + !RightUnaryExpr->isArgumentType()) + return areEquivalentExpr(LeftUnaryExpr->getArgumentExpr(), + RightUnaryExpr->getArgumentExpr()); + + return false; } } @@ -604,23 +618,62 @@ static bool retrieveConstExprFromBothSides(const BinaryOperator *&BinOp, return true; } +static bool isSameRawIdentifierToken(const Token &T1, const Token &T2, + const SourceManager &SM) { + if (T1.getKind() != T2.getKind()) + return false; + if (T1.isNot(tok::raw_identifier)) + return true; + if (T1.getLength() != T2.getLength()) + return false; + return StringRef(SM.getCharacterData(T1.getLocation()), T1.getLength()) == + StringRef(SM.getCharacterData(T2.getLocation()), T2.getLength()); +} + +bool isTokAtEndOfExpr(SourceRange ExprSR, Token T, const SourceManager &SM) { + return SM.getExpansionLoc(ExprSR.getEnd()) == T.getLocation(); +} + +/// Returns true if both LhsEpxr and RhsExpr are +/// macro expressions and they are expanded +/// from different macros. static bool areExprsFromDifferentMacros(const Expr *LhsExpr, const Expr *RhsExpr, const ASTContext *AstCtx) { if (!LhsExpr || !RhsExpr) return false; - - SourceLocation LhsLoc = LhsExpr->getExprLoc(); - SourceLocation RhsLoc = RhsExpr->getExprLoc(); - - if (!LhsLoc.isMacroID() || !RhsLoc.isMacroID()) + SourceRange Lsr = LhsExpr->getSourceRange(); + SourceRange Rsr = RhsExpr->getSourceRange(); + if (!Lsr.getBegin().isMacroID() || !Rsr.getBegin().isMacroID()) return false; const SourceManager &SM = AstCtx->getSourceManager(); const LangOptions &LO = AstCtx->getLangOpts(); - return !(Lexer::getImmediateMacroName(LhsLoc, SM, LO) == - Lexer::getImmediateMacroName(RhsLoc, SM, LO)); + std::pair LsrLocInfo = + SM.getDecomposedLoc(SM.getExpansionLoc(Lsr.getBegin())); + std::pair RsrLocInfo = + SM.getDecomposedLoc(SM.getExpansionLoc(Rsr.getBegin())); + const llvm::MemoryBuffer *MB = SM.getBuffer(LsrLocInfo.first); + + const char *LTokenPos = MB->getBufferStart() + LsrLocInfo.second; + const char *RTokenPos = MB->getBufferStart() + RsrLocInfo.second; + Lexer LRawLex(SM.getLocForStartOfFile(LsrLocInfo.first), LO, + MB->getBufferStart(), LTokenPos, MB->getBufferEnd()); + Lexer RRawLex(SM.getLocForStartOfFile(RsrLocInfo.first), LO, + MB->getBufferStart(), RTokenPos, MB->getBufferEnd()); + + Token LTok, RTok; + do { // Compare the expressions token-by-token. + LRawLex.LexFromRawLexer(LTok); + RRawLex.LexFromRawLexer(RTok); + } while (!LTok.is(tok::eof) && !RTok.is(tok::eof) && + isSameRawIdentifierToken(LTok, RTok, SM) && + !isTokAtEndOfExpr(Lsr, LTok, SM) && + !isTokAtEndOfExpr(Rsr, RTok, SM)); + return (!isTokAtEndOfExpr(Lsr, LTok, SM) || + !isTokAtEndOfExpr(Rsr, RTok, SM)) || + !isSameRawIdentifierToken(LTok, RTok, SM); } static bool areExprsMacroAndNonMacro(const Expr *&LhsExpr, diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc-redundant-expression.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc-redundant-expression.cpp index f6b47eb..5004781 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/misc-redundant-expression.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/misc-redundant-expression.cpp @@ -114,6 +114,7 @@ int Valid(int X, int Y) { #define COND_OP_MACRO 9 #define COND_OP_OTHER_MACRO 9 +#define COND_OP_THIRD_MACRO COND_OP_MACRO int TestConditional(int x, int y) { int k = 0; k += (y < 0) ? x : x; @@ -122,11 +123,27 @@ int TestConditional(int x, int y) { // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: 'true' and 'false' expressions are equivalent k += (y < 0) ? COND_OP_MACRO : COND_OP_MACRO; // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: 'true' and 'false' expressions are equivalent + k += (y < 0) ? COND_OP_MACRO + COND_OP_OTHER_MACRO : COND_OP_MACRO + COND_OP_OTHER_MACRO; + // CHECK-MESSAGES: :[[@LINE-1]]:54: warning: 'true' and 'false' expressions are equivalent // Do not match for conditional operators with a macro and a const. k += (y < 0) ? COND_OP_MACRO : 9; // Do not match for conditional operators with expressions from different macros. k += (y < 0) ? COND_OP_MACRO : COND_OP_OTHER_MACRO; + // Do not match for conditional operators when a macro is defined to another macro + k += (y < 0) ? COND_OP_MACRO : COND_OP_THIRD_MACRO; +#undef COND_OP_THIRD_MACRO +#define COND_OP_THIRD_MACRO 8 + k += (y < 0) ? COND_OP_MACRO : COND_OP_THIRD_MACRO; +#undef COND_OP_THIRD_MACRO + + k += (y < 0) ? sizeof(I64) : sizeof(I64); + // CHECK-MESSAGES: :[[@LINE-1]]:30: warning: 'true' and 'false' expressions are equivalent + k += (y < 0) ? sizeof(TestConditional(k,y)) : sizeof(TestConditional(k,y)); + // CHECK-MESSAGES: :[[@LINE-1]]:47: warning: 'true' and 'false' expressions are equivalent + // No warning if the expression arguments are different. + k += (y < 0) ? sizeof(TestConditional(k,y)) : sizeof(Valid(k,y)); + return k; } #undef COND_OP_MACRO @@ -134,7 +151,7 @@ int TestConditional(int x, int y) { // Overloaded operators that compare two instances of a struct. struct MyStruct { - int x; + int x; bool operator==(const MyStruct& rhs) const {return this->x == rhs.x; } // not modifing bool operator>=(const MyStruct& rhs) const { return this->x >= rhs.x; } // not modifing bool operator<=(MyStruct& rhs) const { return this->x <= rhs.x; } -- 2.7.4