Merge commit '100fbdd06be7590b23c4707a98cd605bdb519498' into merge_20130612

1 files changed, 48 insertions, 18 deletions

diff --git a/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 4e75904..a3a688d 100644
--- a/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -74,6 +74,7 @@
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Triple.h"
 #include "llvm/ADT/ValueMap.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Function.h"
@@ -228,7 +229,7 @@ class MemorySanitizer : public FunctionPass {
   MDNode *ColdCallWeights;
   /// \brief Branch weights for origin store.
   MDNode *OriginStoreWeights;
-  /// \bried Path to blacklist file.
+  /// \brief Path to blacklist file.
   SmallString<64> BlacklistFile;
   /// \brief The blacklist.
   OwningPtr<BlackList> BL;
@@ -299,30 +300,30 @@ void MemorySanitizer::initializeCallbacks(Module &M) {
   RetvalTLS = new GlobalVariable(
     M, ArrayType::get(IRB.getInt64Ty(), 8), false,
     GlobalVariable::ExternalLinkage, 0, "__msan_retval_tls", 0,
-    GlobalVariable::GeneralDynamicTLSModel);
+    GlobalVariable::InitialExecTLSModel);
   RetvalOriginTLS = new GlobalVariable(
     M, OriginTy, false, GlobalVariable::ExternalLinkage, 0,
-    "__msan_retval_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
+    "__msan_retval_origin_tls", 0, GlobalVariable::InitialExecTLSModel);
 
   ParamTLS = new GlobalVariable(
     M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
     GlobalVariable::ExternalLinkage, 0, "__msan_param_tls", 0,
-    GlobalVariable::GeneralDynamicTLSModel);
+    GlobalVariable::InitialExecTLSModel);
   ParamOriginTLS = new GlobalVariable(
     M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage,
-    0, "__msan_param_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
+    0, "__msan_param_origin_tls", 0, GlobalVariable::InitialExecTLSModel);
 
   VAArgTLS = new GlobalVariable(
     M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
     GlobalVariable::ExternalLinkage, 0, "__msan_va_arg_tls", 0,
-    GlobalVariable::GeneralDynamicTLSModel);
+    GlobalVariable::InitialExecTLSModel);
   VAArgOverflowSizeTLS = new GlobalVariable(
     M, IRB.getInt64Ty(), false, GlobalVariable::ExternalLinkage, 0,
     "__msan_va_arg_overflow_size_tls", 0,
-    GlobalVariable::GeneralDynamicTLSModel);
+    GlobalVariable::InitialExecTLSModel);
   OriginTLS = new GlobalVariable(
     M, IRB.getInt32Ty(), false, GlobalVariable::ExternalLinkage, 0,
-    "__msan_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
+    "__msan_origin_tls", 0, GlobalVariable::InitialExecTLSModel);
 
   // We insert an empty inline asm after __msan_report* to avoid callback merge.
   EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
@@ -365,11 +366,13 @@ bool MemorySanitizer::doInitialization(Module &M) {
   appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction(
                       "__msan_init", IRB.getVoidTy(), NULL)), 0);
 
-  new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
-                     IRB.getInt32(TrackOrigins), "__msan_track_origins");
+  if (TrackOrigins)
+    new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
+                       IRB.getInt32(TrackOrigins), "__msan_track_origins");
 
-  new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
-                     IRB.getInt32(ClKeepGoing), "__msan_keep_going");
+  if (ClKeepGoing)
+    new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
+                       IRB.getInt32(ClKeepGoing), "__msan_keep_going");
 
   return true;
 }
@@ -768,14 +771,21 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
           if (AI->hasByValAttr()) {
             // ByVal pointer itself has clean shadow. We copy the actual
             // argument shadow to the underlying memory.
+            // Figure out maximal valid memcpy alignment.
+            unsigned ArgAlign = AI->getParamAlignment();
+            if (ArgAlign == 0) {
+              Type *EltType = A->getType()->getPointerElementType();
+              ArgAlign = MS.TD->getABITypeAlignment(EltType);
+            }
+            unsigned CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
             Value *Cpy = EntryIRB.CreateMemCpy(
-              getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB),
-              Base, Size, AI->getParamAlignment());
+                getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), Base, Size,
+                CopyAlign);
             DEBUG(dbgs() << "  ByValCpy: " << *Cpy << "\n");
             (void)Cpy;
             *ShadowPtr = getCleanShadow(V);
           } else {
-            *ShadowPtr = EntryIRB.CreateLoad(Base);
+            *ShadowPtr = EntryIRB.CreateAlignedLoad(Base, kShadowTLSAlignment);
           }
           DEBUG(dbgs() << "  ARG:    "  << *AI << " ==> " <<
                 **ShadowPtr << "\n");
@@ -784,7 +794,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
             setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
           }
         }
-        ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
+        ArgOffset += DataLayout::RoundUpAlignment(Size, kShadowTLSAlignment);
       }
       assert(*ShadowPtr && "Could not find shadow for an argument");
       return *ShadowPtr;
@@ -1963,9 +1973,29 @@ struct VarArgAMD64Helper : public VarArgHelper {
   }
 };
 
-VarArgHelper* CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
+/// \brief A no-op implementation of VarArgHelper.
+struct VarArgNoOpHelper : public VarArgHelper {
+  VarArgNoOpHelper(Function &F, MemorySanitizer &MS,
+                   MemorySanitizerVisitor &MSV) {}
+
+  void visitCallSite(CallSite &CS, IRBuilder<> &IRB) {}
+
+  void visitVAStartInst(VAStartInst &I) {}
+
+  void visitVACopyInst(VACopyInst &I) {}
+
+  void finalizeInstrumentation() {}
+};
+
+VarArgHelper *CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
                                  MemorySanitizerVisitor &Visitor) {
-  return new VarArgAMD64Helper(Func, Msan, Visitor);
+  // VarArg handling is only implemented on AMD64. False positives are possible
+  // on other platforms.
+  llvm::Triple TargetTriple(Func.getParent()->getTargetTriple());
+  if (TargetTriple.getArch() == llvm::Triple::x86_64)
+    return new VarArgAMD64Helper(Func, Msan, Visitor);
+  else
+    return new VarArgNoOpHelper(Func, Msan, Visitor);
 }
 
 }  // namespace