Author: mstorsjo Date: Mon Feb 26 22:27:06 2018 New Revision: 326173 URL: http://llvm.org/viewvc/llvm-project?rev=326173&view=rev Log: [RecordLayout] Don't align to non-power-of-2 sizes when using -mms-bitfields
When targeting GNU/MinGW for i386, the size of the "long double" data type is 12 bytes (while it is 8 bytes in MSVC). When building with -mms-bitfields to have struct layouts match MSVC, data types are laid out in a struct with alignment according to their size. However, this doesn't make sense for the long double type, since it doesn't match MSVC at all, and aligning to a non-power-of-2 size triggers other asserts later. This matches what GCC does, aligning a long double to 4 bytes in structs on i386 even when -mms-bitfields is specified. This fixes asserts when using the max_align_t data type when building for MinGW/i386 with the -mms-bitfields flag. Differential Revision: https://reviews.llvm.org/D43734 Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp cfe/trunk/test/CodeGen/mingw-long-double.c Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=326173&r1=326172&r2=326173&view=diff ============================================================================== --- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original) +++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Mon Feb 26 22:27:06 2018 @@ -1752,7 +1752,12 @@ void ItaniumRecordLayoutBuilder::LayoutF QualType T = Context.getBaseElementType(D->getType()); if (const BuiltinType *BTy = T->getAs<BuiltinType>()) { CharUnits TypeSize = Context.getTypeSizeInChars(BTy); - if (TypeSize > FieldAlign) + assert( + (llvm::isPowerOf2_64(TypeSize.getQuantity()) || + Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) && + "Non PowerOf2 size outside of GNU mode"); + if (TypeSize > FieldAlign && + llvm::isPowerOf2_64(TypeSize.getQuantity())) FieldAlign = TypeSize; } } Modified: cfe/trunk/test/CodeGen/mingw-long-double.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/mingw-long-double.c?rev=326173&r1=326172&r2=326173&view=diff ============================================================================== --- cfe/trunk/test/CodeGen/mingw-long-double.c (original) +++ cfe/trunk/test/CodeGen/mingw-long-double.c Mon Feb 26 22:27:06 2018 @@ -1,5 +1,7 @@ // RUN: %clang_cc1 -triple i686-windows-gnu -emit-llvm -o - %s \ // RUN: | FileCheck %s --check-prefix=GNU32 +// RUN: %clang_cc1 -triple i686-windows-gnu -emit-llvm -o - %s -mms-bitfields \ +// RUN: | FileCheck %s --check-prefix=GNU32 // RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -o - %s \ // RUN: | FileCheck %s --check-prefix=GNU64 // RUN: %clang_cc1 -triple x86_64-windows-msvc -emit-llvm -o - %s \ _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits