Author: Shafik Yaghmour Date: 2025-05-15T16:04:37-07:00 New Revision: 136f2ba2a7bca015ef831c91fb0db5e5e31b7632
URL: https://github.com/llvm/llvm-project/commit/136f2ba2a7bca015ef831c91fb0db5e5e31b7632 DIFF: https://github.com/llvm/llvm-project/commit/136f2ba2a7bca015ef831c91fb0db5e5e31b7632.diff LOG: [Clang][AST] Fix HandleLValueBase to deal with references (#140105) Since P2280R4 Unknown references and pointers was implemented, HandleLValueBase now has to deal with referneces: D.MostDerivedType->getAsCXXRecordDecl() will return a nullptr if D.MostDerivedType is a ReferenceType. The fix is to use getNonReferenceType() to obtain the Pointee Type if we have a reference. Fixes: https://github.com/llvm/llvm-project/issues/139452 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/AST/ExprConstant.cpp clang/test/SemaCXX/constant-expression-p2280r4.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 985cf264876e9..4e5875c043cf2 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -615,6 +615,8 @@ Bug Fixes in This Version argument which contains a pragma. (#GH113722) - Fixed assertion failures when generating name lookup table in modules. (#GH61065, #GH134739) - Fixed an assertion failure in constant compound literal statements. (#GH139160) +- Fix crash due to unknown references and pointer implementation and handling of + base classes. (GH139452) Bug Fixes to Compiler Builtins ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 86dbb349fd1a7..ca1fbdf7e652f 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -3314,7 +3314,11 @@ static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj, return false; // Extract most-derived object and corresponding type. - DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl(); + // FIXME: After implementing P2280R4 it became possible to get references + // here. We do MostDerivedType->getAsCXXRecordDecl() in several other + // locations and if we see crashes in those locations in the future + // it may make more sense to move this fix into Lvalue::set. + DerivedDecl = D.MostDerivedType.getNonReferenceType()->getAsCXXRecordDecl(); if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength)) return false; diff --git a/clang/test/SemaCXX/constant-expression-p2280r4.cpp b/clang/test/SemaCXX/constant-expression-p2280r4.cpp index 0cdc16ed4e822..88e0a8f153b10 100644 --- a/clang/test/SemaCXX/constant-expression-p2280r4.cpp +++ b/clang/test/SemaCXX/constant-expression-p2280r4.cpp @@ -178,3 +178,24 @@ namespace extern_reference_used_as_unknown { int y; constinit int& g = (x,y); // expected-warning {{left operand of comma operator has no effect}} } + +namespace GH139452 { +struct Dummy { + explicit operator bool() const noexcept { return true; } +}; + +struct Base { int error; }; +struct Derived : virtual Base { }; + +template <class R> +constexpr R get_value() { + const auto& derived_val = Derived{}; + if (derived_val.error != 0) + /* nothing */; + return R{}; +} + +int f() { + return !get_value<Dummy>(); // contextually convert the function call result to bool +} +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
