[asan] Set alignment of __asan_global_* globals to sizeof(GlobalStruct)
When using profiling and ASan together (-fprofile-instr-generate -fcoverage-mapping -fsanitize=address), at least on Darwin, the section of globals that ASan emits (__asan_globals) is misaligned and starts at an odd offset. This really doesn't have anything to do with profiling, but it triggers the issue because profiling emits a string section, which can have arbitrary size. This patch changes the alignment to sizeof(GlobalStruct).
Differential Revision: https://reviews.llvm.org/D28573
llvm-svn: 291715
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 54bdc9e..9c4b417 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1598,8 +1598,7 @@
StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy,
IntptrTy, IntptrTy, IntptrTy, nullptr);
unsigned SizeOfGlobalStruct = DL.getTypeAllocSize(GlobalStructTy);
- assert((isPowerOf2_32(SizeOfGlobalStruct) ||
- !TargetTriple.isOSBinFormatCOFF()) &&
+ assert(isPowerOf2_32(SizeOfGlobalStruct) &&
"global metadata will not be padded appropriately");
SmallVector<Constant *, 16> Initializers(UseMetadataArray ? n : 0);
@@ -1766,13 +1765,11 @@
GlobalValue::getRealLinkageName(G->getName()));
Metadata->setSection(getGlobalMetadataSection());
+ // We don't want any padding, but we also need a reasonable alignment.
// The MSVC linker always inserts padding when linking incrementally. We
// cope with that by aligning each struct to its size, which must be a power
// of two.
- if (TargetTriple.isOSBinFormatCOFF())
- Metadata->setAlignment(SizeOfGlobalStruct);
- else
- Metadata->setAlignment(1); // Don't leave padding in between.
+ Metadata->setAlignment(SizeOfGlobalStruct);
// On platforms that support comdats, put the metadata and the
// instrumented global in the same group. This ensures that the metadata