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[msan] Fix "missing origin" in atomic store. 

An atomic store always make the target location fully initialized (in the
current implementation). It should not store origin. Initialized memory can't
have meaningful origin, and, due to origin granularity (4 bytes) there is a
chance that this extra store would overwrite meaningfull origin for an adjacent
location.

llvm-svn: 228444
This commit is contained in:
Evgeniy Stepanov 2015-02-06 21:47:39 +00:00
parent be9c91173f
commit 4e12057760
2 changed files with 3 additions and 1 deletions
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2
llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
View File

@ -702,7 +702,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (SI.isAtomic()) SI.setOrdering(addReleaseOrdering(SI.getOrdering()));
if (MS.TrackOrigins)
if (MS.TrackOrigins && !SI.isAtomic())
storeOrigin(IRB, Addr, Shadow, getOrigin(Val), SI.getAlignment(),
InstrumentWithCalls);
}

2
llvm/test/Instrumentation/MemorySanitizer/atomics.ll
View File

@ -1,4 +1,6 @@
; RUN: opt < %s -msan -msan-check-access-address=0 -S | FileCheck %s
; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=1 -S | FileCheck %s
; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=2 -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"