https://github.com/martinboehme created https://github.com/llvm/llvm-project/pull/96731
We were previously treating the operand of `typeid()` as being definitely unevaluated, but it can be evaluated if it is a glvalue of polymorphic type. This patch includes a test that fails without the fix. >From 2e80e59fccc7ced7539fa2ee70e33545ce0e1441 Mon Sep 17 00:00:00 2001 From: Martin Braenne <mboe...@google.com> Date: Wed, 26 Jun 2024 04:44:53 +0000 Subject: [PATCH] [clang][dataflow] Teach `AnalysisASTVisitor` that `typeid()` can be evaluated. We were previously treating the operand of `typeid()` as being definitely unevaluated, but it can be evaluated if it is a glvalue of polymorphic type. This patch includes a test that fails without the fix. --- .../clang/Analysis/FlowSensitive/ASTOps.h | 6 ++- .../Analysis/FlowSensitive/TransferTest.cpp | 43 +++++++++++++++++++ 2 files changed, 48 insertions(+), 1 deletion(-) diff --git a/clang/include/clang/Analysis/FlowSensitive/ASTOps.h b/clang/include/clang/Analysis/FlowSensitive/ASTOps.h index 925b99af9141a..f9c923a36ad22 100644 --- a/clang/include/clang/Analysis/FlowSensitive/ASTOps.h +++ b/clang/include/clang/Analysis/FlowSensitive/ASTOps.h @@ -113,7 +113,11 @@ class AnalysisASTVisitor : public RecursiveASTVisitor<Derived> { // nevertheless it appears in the Clang CFG, so we don't exclude it here. bool TraverseDecltypeTypeLoc(DecltypeTypeLoc) { return true; } bool TraverseTypeOfExprTypeLoc(TypeOfExprTypeLoc) { return true; } - bool TraverseCXXTypeidExpr(CXXTypeidExpr *) { return true; } + bool TraverseCXXTypeidExpr(CXXTypeidExpr *TIE) { + if (TIE->isPotentiallyEvaluated()) + return RecursiveASTVisitor<Derived>::TraverseCXXTypeidExpr(TIE); + return true; + } bool TraverseUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *) { return true; } diff --git a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp index 2a74d7fa63fd7..10d7ec9380ab8 100644 --- a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp +++ b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp @@ -1637,6 +1637,49 @@ TEST(TransferTest, StructModeledFieldsWithAccessor) { }); } +TEST(TransferTest, StructModeledFieldsInTypeid) { + // Test that we model fields mentioned inside a `typeid()` expression only if + // that expression is potentially evaluated -- i.e. if the expression inside + // `typeid()` is a glvalue of polymorphic type (see + // `CXXTypeidExpr::isPotentiallyEvaluated()` and [expr.typeid]p3). + std::string Code = R"( + // Definitions needed for `typeid`. + namespace std { + class type_info {}; + class bad_typeid {}; + } // namespace std + + struct NonPolymorphic {}; + + struct Polymorphic { + virtual ~Polymorphic() = default; + }; + + struct S { + NonPolymorphic *NonPoly; + Polymorphic *Poly; + }; + + void target(S &s) { + typeid(*s.NonPoly); + typeid(*s.Poly); + // [[p]] + } + )"; + runDataflow( + Code, + [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results, + ASTContext &ASTCtx) { + const Environment &Env = getEnvironmentAtAnnotation(Results, "p"); + auto &SLoc = getLocForDecl<RecordStorageLocation>(ASTCtx, Env, "s"); + std::vector<const ValueDecl *> Fields; + for (auto [Field, _] : SLoc.children()) + Fields.push_back(Field); + EXPECT_THAT(Fields, + UnorderedElementsAre(findValueDecl(ASTCtx, "Poly"))); + }); +} + TEST(TransferTest, StructModeledFieldsWithComplicatedInheritance) { std::string Code = R"( struct Base1 { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits