llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Shafik Yaghmour (shafik) <details> <summary>Changes</summary> 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 --- Full diff: https://github.com/llvm/llvm-project/pull/140105.diff 3 Files Affected: - (modified) clang/docs/ReleaseNotes.rst (+2) - (modified) clang/lib/AST/ExprConstant.cpp (+5-1) - (modified) clang/test/SemaCXX/constant-expression-p2280r4.cpp (+21) ``````````diff diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 31c517338c21f..25e3e4105b3f1 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -597,6 +597,8 @@ Bug Fixes in This Version - Fixed a crash with an invalid member function parameter list with a default argument which contains a pragma. (#GH113722) - Fixed assertion failures when generating name lookup table in modules. (#GH61065, #GH134739) +- 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 +} +} `````````` </details> https://github.com/llvm/llvm-project/pull/140105 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
