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| author | Tom Tan <Tom.Tan@microsoft.com> | 2019-05-02 00:38:14 +0000 |
|---|---|---|
| committer | Tom Tan <Tom.Tan@microsoft.com> | 2019-05-02 00:38:14 +0000 |
| commit | b7c6d95af5e295c560d1445e7090e31eb9289932 (patch) | |
| tree | 17dc636dd19bfc8769acfe505a445ae1051a54c2 /clang/test/CodeGen/arm64-microsoft-struct-align.cpp | |
| parent | a78ab77b6b784417a00287b082ab331355da2026 (diff) | |
| download | bcm5719-llvm-b7c6d95af5e295c560d1445e7090e31eb9289932.tar.gz bcm5719-llvm-b7c6d95af5e295c560d1445e7090e31eb9289932.zip | |
[COFF, ARM64] Align global symbol by size for ARM64 MSVC ABI
According to alignment section in below ARM64 ABI document, MSVC could increase
alignment of global data based on its total size. Clang doesn't do this. Compile
the same symbol into different alignments by Clang and MSVC could cause link
error because some instruction encodings, like 64-bit LDR/STR with immediate,
require the target to be 8 bytes aligned, and linker could choose code stream
with such LDR/STR instruction from MSVC and 4 bytes aligned data from Clang into
final image, which actually cannot be linked together
(see https://bugs.llvm.org/show_bug.cgi?id=41506 for more details).
https://docs.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=vs-2019#alignment
Differential Revision: https://reviews.llvm.org/D61225
llvm-svn: 359744
Diffstat (limited to 'clang/test/CodeGen/arm64-microsoft-struct-align.cpp')
| -rw-r--r-- | clang/test/CodeGen/arm64-microsoft-struct-align.cpp | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/clang/test/CodeGen/arm64-microsoft-struct-align.cpp b/clang/test/CodeGen/arm64-microsoft-struct-align.cpp new file mode 100644 index 00000000000..4076c3ca34a --- /dev/null +++ b/clang/test/CodeGen/arm64-microsoft-struct-align.cpp @@ -0,0 +1,27 @@ +// RUN: %clang_cc1 -triple aarch64-windows -ffreestanding -emit-llvm -O0 \ +// RUN: -x c++ -o - %s | FileCheck %s + +struct size1 { char str[1]; }; +struct size2 { char str[2]; }; +struct size7 { char str[4]; }; +struct size8 { char str[8]; }; +struct size63 { char str[63]; }; +struct size64 { char str[64]; }; + +struct size1 s1; +// CHECK: @"?s1@@3Usize1@@A" = dso_local global %struct.size1 zeroinitializer, align 1 + +struct size2 s2; +// CHECK: @"?s2@@3Usize2@@A" = dso_local global %struct.size2 zeroinitializer, align 4 + +struct size7 s7; +// CHECK: @"?s7@@3Usize7@@A" = dso_local global %struct.size7 zeroinitializer, align 4 + +struct size8 s8; +// CHECK: @"?s8@@3Usize8@@A" = dso_local global %struct.size8 zeroinitializer, align 8 + +struct size63 s63; +// CHECK: @"?s63@@3Usize63@@A" = dso_local global %struct.size63 zeroinitializer, align 8 + +struct size64 s64; +// CHECK: @"?s64@@3Usize64@@A" = dso_local global %struct.size64 zeroinitializer, align 16 |
