Author: Tobias Hieta Date: 2022-08-25T09:00:25+02:00 New Revision: 12f27d8bef9387e2e3837f604ccd8a457d927053
URL: https://github.com/llvm/llvm-project/commit/12f27d8bef9387e2e3837f604ccd8a457d927053 DIFF: https://github.com/llvm/llvm-project/commit/12f27d8bef9387e2e3837f604ccd8a457d927053.diff LOG: Revert "GCC ABI Compatibility: Preserve alignment of non-pod members in packed structs" This reverts commit 277123376ce08c98b07c154bf83e4092a5d4d3c6. See issue: https://github.com/llvm/llvm-project/issues/57346 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/AST/RecordLayoutBuilder.cpp clang/test/SemaCXX/class-layout.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 906c1925bc823..87d906a302f83 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -574,11 +574,6 @@ OpenCL C Language Changes in Clang ABI Changes in Clang -------------------- -- GCC doesn't pack non-POD members in packed structs unless the packed - attribute is also specified on the member. Clang historically did perform - such packing. Clang now matches the gcc behavior (except on Darwin and PS4). - You can switch back to the old ABI behavior with the flag: - ``-fclang-abi-compat=14.0``. - When compiling C for ARM or AArch64, a zero-length bitfield in a ``struct`` (e.g. ``int : 0``) no longer prevents the structure from being considered a homogeneous floating-point or vector aggregate. The new behavior agrees with diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp index 6f3ede2ce42a7..5ddd95e2ecca6 100644 --- a/clang/lib/AST/RecordLayoutBuilder.cpp +++ b/clang/lib/AST/RecordLayoutBuilder.cpp @@ -1889,12 +1889,7 @@ void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D, UnfilledBitsInLastUnit = 0; LastBitfieldStorageUnitSize = 0; - llvm::Triple Target = Context.getTargetInfo().getTriple(); - bool FieldPacked = (Packed && (!FieldClass || FieldClass->isPOD() || - Context.getLangOpts().getClangABICompat() <= - LangOptions::ClangABI::Ver14 || - Target.isPS() || Target.isOSDarwin())) || - D->hasAttr<PackedAttr>(); + bool FieldPacked = Packed || D->hasAttr<PackedAttr>(); AlignRequirementKind AlignRequirement = AlignRequirementKind::None; CharUnits FieldSize; diff --git a/clang/test/SemaCXX/class-layout.cpp b/clang/test/SemaCXX/class-layout.cpp index f81e526d0e2ad..5403bd6e6a6f6 100644 --- a/clang/test/SemaCXX/class-layout.cpp +++ b/clang/test/SemaCXX/class-layout.cpp @@ -1,10 +1,6 @@ // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=14 -// RUN: %clang_cc1 -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6 -// RUN: %clang_cc1 -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6 // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6 -// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14 // expected-no-diagnostics #define SA(n, p) int a##n[(p) ? 1 : -1] @@ -608,37 +604,3 @@ namespace PR37275 { #endif #pragma pack(pop) } - -namespace non_pod { -struct t1 { -protected: - int a; -}; -// GCC prints warning: ignoring packed attribute because of unpacked non-POD field 't1 t2::v1'` -struct t2 { - char c1; - short s1; - char c2; - t1 v1; -} __attribute__((packed)); -#if defined(CLANG_ABI_COMPAT) && CLANG_ABI_COMPAT <= 14 -_Static_assert(_Alignof(t1) == 4, ""); -_Static_assert(_Alignof(t2) == 1, ""); -#else -_Static_assert(_Alignof(t1) == 4, ""); -_Static_assert(_Alignof(t2) == 4, ""); -#endif -_Static_assert(sizeof(t2) == 8, ""); // it's still packing the rest of the struct -} // namespace non_pod - -namespace non_pod_packed { -struct t1 { -protected: - int a; -} __attribute__((packed)); -struct t2 { - t1 v1; -} __attribute__((packed)); -_Static_assert(_Alignof(t1) == 1, ""); -_Static_assert(_Alignof(t2) == 1, ""); -} // namespace non_pod_packed _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
