https://github.com/antoniofrighetto updated https://github.com/llvm/llvm-project/pull/127824
>From 1c7357a3279322ba469c1293d49bfba67b0565b5 Mon Sep 17 00:00:00 2001 From: Antonio Frighetto <m...@antoniofrighetto.com> Date: Wed, 19 Feb 2025 16:47:18 +0100 Subject: [PATCH] [clang][Sema] Propagate `volatile` during derived-to-base conversion When accessing a field member through a derived-to-base conversion, ensure the `volatile` qualifier is propagated to the base type. Fixes: https://github.com/llvm/llvm-project/issues/127683. --- clang/lib/Sema/SemaExpr.cpp | 7 ++++-- .../SemaCXX/derived-to-base-volatile-qual.cpp | 23 +++++++++++++++++++ 2 files changed, 28 insertions(+), 2 deletions(-) create mode 100644 clang/test/SemaCXX/derived-to-base-volatile-qual.cpp diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index fad15bf95c415..f9b9a05ce3da6 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -3107,8 +3107,11 @@ Sema::PerformObjectMemberConversion(Expr *From, /*IgnoreAccess=*/true)) return ExprError(); - return ImpCastExprToType(From, DestType, CK_UncheckedDerivedToBase, - VK, &BasePath); + if (FromType.isVolatileQualified()) + DestType.addVolatile(); + + return ImpCastExprToType(From, DestType, CK_UncheckedDerivedToBase, VK, + &BasePath); } bool Sema::UseArgumentDependentLookup(const CXXScopeSpec &SS, diff --git a/clang/test/SemaCXX/derived-to-base-volatile-qual.cpp b/clang/test/SemaCXX/derived-to-base-volatile-qual.cpp new file mode 100644 index 0000000000000..67df441b99a2a --- /dev/null +++ b/clang/test/SemaCXX/derived-to-base-volatile-qual.cpp @@ -0,0 +1,23 @@ +// RUN: %clang_cc1 -std=c++20 -fsyntax-only -ast-dump %s | FileCheck %s + +// Ensure volatile is preserved during derived-to-base conversion. +namespace PR127683 { + +struct Base { + int Val; +}; + +struct Derived : Base { }; + +volatile Derived Obj; + +// CHECK: `-FunctionDecl {{.*}} test_volatile_store 'void ()' +// CHECK-NEXT: `-CompoundStmt {{.*}} +// CHECK-NEXT: `-BinaryOperator {{.*}} 'volatile int' lvalue '=' +// CHECK-NEXT: |-MemberExpr {{.*}} 'volatile int' lvalue .Val +// CHECK-NEXT: | `-ImplicitCastExpr {{.*}} 'volatile PR127683::Base' lvalue <UncheckedDerivedToBase (Base)> +void test_volatile_store() { + Obj.Val = 0; +} + +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
