Merging r326173:
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r326173 | mstorsjo | 2018-02-26 22:27:06 -0800 (Mon, 26 Feb 2018) | 17 lines
[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
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_60@333569 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index a9d43df..240e7f6 100644
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -1751,7 +1751,12 @@
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;
}
}
diff --git a/test/CodeGen/mingw-long-double.c b/test/CodeGen/mingw-long-double.c
index 1c7c31f..166f7de 100644
--- a/test/CodeGen/mingw-long-double.c
+++ b/test/CodeGen/mingw-long-double.c
@@ -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 \
