[llvm-commits] [llvm] r169859 - /llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp

[Evgeniy Stepanov]

Author: eugenis
Date: Tue Dec 11 06:34:09 2012
New Revision: 169859

URL: http://llvm.org/viewvc/llvm-project?rev=169859&view=rev
Log:
[msan] Use explicitely aligned stores and loads with function argument shadow.

Use explicitely aligned store and load instructions to deal with argument and
retval shadow. This matters when an argument's alignment is higher than
__msan_param_tls alignment (which is the case with __m128i).


Modified:
    llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp

Modified: llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp?rev=169859&r1=169858&r2=169859&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp Tue Dec 11 06:34:09 2012
@@ -76,6 +76,7 @@
 static const uint64_t kShadowMask64 = 1ULL << 46;
 static const uint64_t kOriginOffset32 = 1ULL << 30;
 static const uint64_t kOriginOffset64 = 1ULL << 45;
+static const uint64_t kShadowTLSAlignment = 8;
 
 // This is an important flag that makes the reports much more
 // informative at the cost of greater slowdown. Not fully implemented
@@ -1226,11 +1227,13 @@
                                  Size, Alignment);
       } else {
         Size = MS.TD->getTypeAllocSize(A->getType());
-        Store = IRB.CreateStore(ArgShadow, ArgShadowBase);
+        Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
+                                       kShadowTLSAlignment);
       }
       if (ClTrackOrigins)
-        IRB.CreateStore(getOrigin(A),
-                        getOriginPtrForArgument(A, IRB, ArgOffset));
+        IRB.CreateAlignedStore(getOrigin(A),
+                               getOriginPtrForArgument(A, IRB, ArgOffset),
+                               kShadowTLSAlignment);
       assert(Size != 0 && Store != 0);
       DEBUG(dbgs() << "  Param:" << *Store << "\n");
       ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
@@ -1248,7 +1251,7 @@
     IRBuilder<> IRBBefore(&I);
     // Untill we have full dynamic coverage, make sure the retval shadow is 0.
     Value *Base = getShadowPtrForRetval(&I, IRBBefore);
-    IRBBefore.CreateStore(getCleanShadow(&I), Base);
+    IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base, kShadowTLSAlignment);
     Instruction *NextInsn = 0;
     if (CS.isCall()) {
       NextInsn = I.getNextNode();
@@ -1267,8 +1270,10 @@
              "Could not find insertion point for retval shadow load");
     }
     IRBuilder<> IRBAfter(NextInsn);
-    setShadow(&I, IRBAfter.CreateLoad(getShadowPtrForRetval(&I, IRBAfter),
-                                      "_msret"));
+    Value *RetvalShadow =
+      IRBAfter.CreateAlignedLoad(getShadowPtrForRetval(&I, IRBAfter),
+                                 kShadowTLSAlignment, "_msret");
+    setShadow(&I, RetvalShadow);
     if (ClTrackOrigins)
       setOrigin(&I, IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter)));
   }
@@ -1280,7 +1285,7 @@
       Value *Shadow = getShadow(RetVal);
       Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
       DEBUG(dbgs() << "Return: " << *Shadow << "\n" << *ShadowPtr << "\n");
-      IRB.CreateStore(Shadow, ShadowPtr);
+      IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
       if (ClTrackOrigins)
         IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
     }
@@ -1471,7 +1476,7 @@
         Base = getShadowPtrForVAArgument(A, IRB, OverflowOffset);
         OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
       }
-      IRB.CreateStore(MSV.getShadow(A), Base);
+      IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
     }
     Constant *OverflowSize =
       ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);