llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-tools-extra Author: Julian Schmidt (5chmidti) <details> <summary>Changes</summary> A `const &` parameter can also be returned via a conditional operator: `c ? a : b`. This change adds support for diagnosing returning these parameters with conditional operators. --- Full diff: https://github.com/llvm/llvm-project/pull/107657.diff 3 Files Affected: - (modified) clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp (+21-16) - (modified) clang-tools-extra/docs/ReleaseNotes.rst (+6) - (modified) clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp (+9) ``````````diff diff --git a/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp index adb26ade955c5e..9c12b8fb12838c 100644 --- a/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp +++ b/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp @@ -7,6 +7,7 @@ //===----------------------------------------------------------------------===// #include "ReturnConstRefFromParameterCheck.h" +#include "clang/AST/Expr.h" #include "clang/ASTMatchers/ASTMatchFinder.h" #include "clang/ASTMatchers/ASTMatchers.h" @@ -15,20 +16,24 @@ using namespace clang::ast_matchers; namespace clang::tidy::bugprone { void ReturnConstRefFromParameterCheck::registerMatchers(MatchFinder *Finder) { - Finder->addMatcher( - returnStmt( - hasReturnValue(declRefExpr( - to(parmVarDecl(hasType(hasCanonicalType( - qualType(lValueReferenceType(pointee( - qualType(isConstQualified())))) - .bind("type")))) - .bind("param")))), - hasAncestor( - functionDecl(hasReturnTypeLoc(loc(qualType( - hasCanonicalType(equalsBoundNode("type")))))) - .bind("func"))) - .bind("ret"), - this); + const auto DRef = + declRefExpr( + to(parmVarDecl(hasType(hasCanonicalType( + qualType(lValueReferenceType(pointee( + qualType(isConstQualified())))) + .bind("type")))) + .bind("param"))) + .bind("dref"); + const auto Func = + functionDecl(hasReturnTypeLoc(loc( + qualType(hasCanonicalType(equalsBoundNode("type")))))) + .bind("func"); + + Finder->addMatcher(returnStmt(hasReturnValue(DRef), hasAncestor(Func)), this); + Finder->addMatcher(conditionalOperator(eachOf(hasTrueExpression(DRef), + hasFalseExpression(DRef)), + hasAncestor(Func)), + this); } static bool isSameTypeIgnoringConst(QualType A, QualType B) { @@ -85,8 +90,8 @@ void ReturnConstRefFromParameterCheck::check( const MatchFinder::MatchResult &Result) { const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("func"); const auto *PD = Result.Nodes.getNodeAs<ParmVarDecl>("param"); - const auto *R = Result.Nodes.getNodeAs<ReturnStmt>("ret"); - const SourceRange Range = R->getRetValue()->getSourceRange(); + const auto *DRef = Result.Nodes.getNodeAs<DeclRefExpr>("dref"); + const SourceRange Range = DRef->getSourceRange(); if (Range.isInvalid()) return; diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 8d028f8863cb7a..969e514ee630ea 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -108,6 +108,12 @@ Changes in existing checks <clang-tidy/checks/bugprone/casting-through-void>` check to suggest replacing the offending code with ``reinterpret_cast``, to more clearly express intent. +- Improved :doc:`bugprone-return-const-ref-from-parameter + <clang-tidy/checks/bugprone/return-const-ref-from-parameter>` check to + diagnose potential dangling references when returning a ``const &`` parameter + by using the conditional operator ``cond ? var1 : var2``. + + - Improved :doc:`modernize-use-std-format <clang-tidy/checks/modernize/use-std-format>` check to support replacing member function calls too. diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp index d13c127da7c2a1..d83d997a455d50 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp @@ -27,6 +27,10 @@ int const &f3(TConstRef a) { return a; } int const &f4(TConst &a) { return a; } // CHECK-MESSAGES: :[[@LINE-1]]:35: warning: returning a constant reference parameter +int const &f5(TConst &a) { return true ? a : a; } +// CHECK-MESSAGES: :[[@LINE-1]]:42: warning: returning a constant reference parameter +// CHECK-MESSAGES: :[[@LINE-2]]:46: warning: returning a constant reference parameter + template <typename T> const T& tf1(const T &a) { return a; } // CHECK-MESSAGES: :[[@LINE-1]]:35: warning: returning a constant reference parameter @@ -47,6 +51,11 @@ template <typename T> const T& itf4(typename ConstRef<T>::type a) { return a; } // CHECK-MESSAGES: :[[@LINE-1]]:54: warning: returning a constant reference parameter +template <typename T> +const T& itf5(const T &a) { return true ? a : a; } +// CHECK-MESSAGES: :[[@LINE-1]]:43: warning: returning a constant reference parameter +// CHECK-MESSAGES: :[[@LINE-2]]:47: warning: returning a constant reference parameter + void instantiate(const int ¶m, const float ¶mf, int &mut_param, float &mut_paramf) { itf1(0); itf1(param); `````````` </details> https://github.com/llvm/llvm-project/pull/107657 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
