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[msan] Fix handling of byval arguments with large alignment. 

MSan param-tls slots are 8-byte aligned. This change clips
alignment of memcpy into param-tls to 8.

llvm-svn: 220101
This commit is contained in:
Evgeniy Stepanov 2014-10-17 23:29:44 +00:00
parent 766cf60961
commit e08633e900
2 changed files with 22 additions and 1 deletions
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3
llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
View File

@ -2329,7 +2329,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
assert(A->getType()->isPointerTy() &&
"ByVal argument is not a pointer!");
Size = MS.DL->getTypeAllocSize(A->getType()->getPointerElementType());
unsigned Alignment = CS.getParamAlignment(i + 1);
unsigned ParamAlignment = CS.getParamAlignment(i + 1);
unsigned Alignment = std::min(ParamAlignment, kShadowTLSAlignment);
Store = IRB.CreateMemCpy(ArgShadowBase,
getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB),
Size, Alignment);

20
llvm/test/Instrumentation/MemorySanitizer/byval-alignment.ll Normal file
View File

@ -0,0 +1,20 @@
; Test that copy alignment for byval arguments is limited by param-tls slot alignment.
; RUN: opt < %s -msan -msan-check-access-address=0 -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%struct.S = type { i64, i64, i64, [8 x i8] }
; CHECK: [[A:%.*]] = bitcast i64* {{.*}} add {{.*}} ptrtoint {{.*}} @__msan_param_tls {{.*}} i64 8)
; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[A]], i8* {{.*}}, i64 32, i32 8, i1 false)
define void @Caller() sanitize_memory {
entry:
%agg.tmp = alloca %struct.S, align 16
call void @Callee(i32 1, %struct.S* byval align 16 %agg.tmp)
ret void
}
declare void @Callee(i32, %struct.S* byval align 16)