================ @@ -0,0 +1,89 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "LoopVariableCopiedThenModifiedCheck.h" +#include "../utils/Matchers.h" +#include "../utils/TypeTraits.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/Analysis/Analyses/ExprMutationAnalyzer.h" +#include "clang/Basic/Diagnostic.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::bugprone { + +LoopVariableCopiedThenModifiedCheck::LoopVariableCopiedThenModifiedCheck( + StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context), + IgnoreInexpensiveVariables( + Options.get("IgnoreInexpensiveVariables", false)) {} + +void LoopVariableCopiedThenModifiedCheck::storeOptions( + ClangTidyOptions::OptionMap &Opts) { + Options.store(Opts, "IgnoreInexpensiveVariables", IgnoreInexpensiveVariables); +} + +void LoopVariableCopiedThenModifiedCheck::registerMatchers( + MatchFinder *Finder) { + const auto HasReferenceOrPointerTypeOrIsAllowed = hasType(qualType( + unless(hasCanonicalType(anyOf(referenceType(), pointerType()))))); + const auto IteratorReturnsValueType = cxxOperatorCallExpr( + hasOverloadedOperatorName("*"), + callee( + cxxMethodDecl(returns(unless(hasCanonicalType(referenceType())))))); + const auto NotConstructedByCopy = cxxConstructExpr( + hasDeclaration(cxxConstructorDecl(unless(isCopyConstructor())))); + const auto ConstructedByConversion = + cxxMemberCallExpr(callee(cxxConversionDecl())); + const auto LoopVar = + varDecl(HasReferenceOrPointerTypeOrIsAllowed, + unless(hasInitializer(expr(hasDescendant(expr( + anyOf(materializeTemporaryExpr(), IteratorReturnsValueType, + NotConstructedByCopy, ConstructedByConversion))))))); + Finder->addMatcher(cxxForRangeStmt(hasLoopVariable(LoopVar.bind("loopVar"))) + .bind("forRange"), + this); +} + +void LoopVariableCopiedThenModifiedCheck::check( + const MatchFinder::MatchResult &Result) { + const auto *LoopVar = Result.Nodes.getNodeAs<VarDecl>("loopVar"); + if (LoopVar->getBeginLoc().isMacroID()) + return; + std::optional<bool> Expensive = utils::type_traits::isExpensiveToCopy( + LoopVar->getType(), *Result.Context); + if ((!Expensive || !*Expensive) && IgnoreInexpensiveVariables) + return; + const auto *ForRange = Result.Nodes.getNodeAs<CXXForRangeStmt>("forRange"); + + std::string HintString = ""; + + if (ExprMutationAnalyzer(*ForRange->getBody(), *Result.Context) + .isMutated(LoopVar)) { + if (isa<AutoType>(LoopVar->getType())) { + HintString = "const auto&"; + } else { + const std::string CanonicalTypeStr = + LoopVar->getType().getAsString(Result.Context->getLangOpts()); + HintString = "const " + CanonicalTypeStr + "&"; + } + clang::SourceRange LoopVarSourceRange = + LoopVar->getTypeSourceInfo()->getTypeLoc().getSourceRange(); + diag(LoopVar->getLocation(), "loop variable '%0' is copied and then " + "modified, which is likely a bug; you " + "probably want to modify the underlying " + "object and not this copy. If you " + "*did* intend to modify this copy, " + "please use an explicit copy inside the " + "body of the loop") ---------------- vbvictor wrote:
The user would read documentation if necessary - the diagnostic should be concise. https://github.com/llvm/llvm-project/pull/157213 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
