The patch resolves the conflict between AddressSanitizer and load widening (GVN).

The problem initially reported by Mozilla folks (http://code.google.com/p/address-sanitizer/issues/detail?id=20),
but it also prevents us from enabling LLVM bootstrap with AddressSanitizer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149925 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 30f8d94698..cfaf2da6ce 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -323,6 +323,14 @@ getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs,
         !TD.fitsInLegalInteger(NewLoadByteSize*8))
       return 0;
 
+    if (LIOffs+NewLoadByteSize > MemLocEnd &&
+        LI->getParent()->getParent()->hasFnAttr(Attribute::AddressSafety)) {
+      // We will be reading past the location accessed by the original program.
+      // While this is safe in a regular build, Address Safety analysis tools
+      // may start reporting false warnings. So, don't do widening.
+      return 0;
+    }
+
     // If a load of this width would include all of MemLoc, then we succeed.
     if (LIOffs+NewLoadByteSize >= MemLocEnd)
       return NewLoadByteSize;