1 files changed, 40 insertions, 38 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 1bb57b6e2bb..74ad9dcf463 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1174,7 +1174,8 @@ LValue CodeGenFunction::EmitLValue(const Expr *E) {
       llvm::Value *V = LV.getPointer();
       Scope.ForceCleanup({&V});
       return LValue::MakeAddr(Address(V, LV.getAlignment()), LV.getType(),
-                              getContext(), LV.getBaseInfo(), LV.getTBAAInfo());
+                              getContext(), LV.getBaseInfo(),
+                              LV.getTBAAAccessType());
     }
     // FIXME: Is it possible to create an ExprWithCleanups that produces a
     // bitfield lvalue or some other non-simple lvalue?
@@ -1513,7 +1514,7 @@ llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
 
   // Atomic operations have to be done on integral types.
   LValue AtomicLValue =
-      LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo);
+      LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo.AccessType);
   if (Ty->isAtomicType() || LValueIsSuitableForInlineAtomic(AtomicLValue)) {
     return EmitAtomicLoad(AtomicLValue, Loc).getScalarVal();
   }
@@ -1524,10 +1525,14 @@ llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
         Load->getContext(), llvm::ConstantAsMetadata::get(Builder.getInt32(1)));
     Load->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
   }
-
-  if (BaseInfo.getMayAlias())
-    TBAAInfo = CGM.getTBAAMayAliasAccessInfo();
-  CGM.DecorateInstructionWithTBAA(Load, TBAAInfo);
+  if (TBAAInfo.AccessType) {
+    bool MayAlias = BaseInfo.getMayAlias();
+    llvm::MDNode *TBAA = MayAlias
+        ? CGM.getTBAAMayAliasTypeInfo()
+        : CGM.getTBAAStructTagInfo(TBAAInfo);
+    if (TBAA)
+      CGM.DecorateInstructionWithTBAA(Load, TBAA, MayAlias);
+  }
 
   if (EmitScalarRangeCheck(Load, Ty, Loc)) {
     // In order to prevent the optimizer from throwing away the check, don't
@@ -1594,7 +1599,7 @@ void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, Address Addr,
   Value = EmitToMemory(Value, Ty);
 
   LValue AtomicLValue =
-      LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo);
+      LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo.AccessType);
   if (Ty->isAtomicType() ||
       (!isInit && LValueIsSuitableForInlineAtomic(AtomicLValue))) {
     EmitAtomicStore(RValue::get(Value), AtomicLValue, isInit);
@@ -1608,10 +1613,14 @@ void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, Address Addr,
                           llvm::ConstantAsMetadata::get(Builder.getInt32(1)));
     Store->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
   }
-
-  if (BaseInfo.getMayAlias())
-    TBAAInfo = CGM.getTBAAMayAliasAccessInfo();
-  CGM.DecorateInstructionWithTBAA(Store, TBAAInfo);
+  if (TBAAInfo.AccessType) {
+    bool MayAlias = BaseInfo.getMayAlias();
+    llvm::MDNode *TBAA = MayAlias
+        ? CGM.getTBAAMayAliasTypeInfo()
+        : CGM.getTBAAStructTagInfo(TBAAInfo);
+    if (TBAA)
+      CGM.DecorateInstructionWithTBAA(Store, TBAA, MayAlias);
+  }
 }
 
 void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
@@ -3718,9 +3727,12 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
 
       // Loading the reference will disable path-aware TBAA.
       TBAAPath = false;
-      TBAAAccessInfo TBAAInfo = mayAlias ? CGM.getTBAAMayAliasAccessInfo() :
-                                           CGM.getTBAAAccessInfo(type);
-      CGM.DecorateInstructionWithTBAA(load, TBAAInfo);
+      if (CGM.shouldUseTBAA()) {
+        llvm::MDNode *tbaa = mayAlias ? CGM.getTBAAMayAliasTypeInfo() :
+                                        CGM.getTBAATypeInfo(type);
+        if (tbaa)
+          CGM.DecorateInstructionWithTBAA(load, tbaa);
+      }
 
       mayAlias = false;
       type = refType->getPointeeType();
@@ -3750,33 +3762,17 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
 
   LValue LV = MakeAddrLValue(addr, type, FieldBaseInfo);
   LV.getQuals().addCVRQualifiers(cvr);
-
-  // Fields of may_alias structs act like 'char' for TBAA purposes.
-  // FIXME: this should get propagated down through anonymous structs
-  // and unions.
-  if (mayAlias) {
-    LV.setTBAAInfo(CGM.getTBAAMayAliasAccessInfo());
-  } else if (TBAAPath) {
-    // If no base type been assigned for the base access, then try to generate
-    // one for this base lvalue.
-    TBAAAccessInfo TBAAInfo = base.getTBAAInfo();
-    if (!TBAAInfo.BaseType) {
-        TBAAInfo.BaseType = CGM.getTBAABaseTypeInfo(base.getType());
-        assert(!TBAAInfo.Offset &&
-               "Nonzero offset for an access with no base type!");
-    }
-
-    // Adjust offset to be relative to the base type.
+  if (TBAAPath) {
     const ASTRecordLayout &Layout =
         getContext().getASTRecordLayout(field->getParent());
+    // Set the base type to be the base type of the base LValue and
+    // update offset to be relative to the base type.
     unsigned CharWidth = getContext().getCharWidth();
-    if (TBAAInfo.BaseType)
-      TBAAInfo.Offset +=
-          Layout.getFieldOffset(field->getFieldIndex()) / CharWidth;
-
-    // Update the final access type.
-    TBAAInfo.AccessType = LV.getTBAAInfo().AccessType;
-
+    TBAAAccessInfo TBAAInfo = mayAlias ?
+      TBAAAccessInfo(CGM.getTBAAMayAliasTypeInfo()) :
+      TBAAAccessInfo(base.getTBAAInfo().BaseType, CGM.getTBAATypeInfo(type),
+                     base.getTBAAInfo().Offset + Layout.getFieldOffset(
+                         field->getFieldIndex()) / CharWidth);
     LV.setTBAAInfo(TBAAInfo);
   }
 
@@ -3784,6 +3780,12 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
   if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
     LV.getQuals().removeObjCGCAttr();
 
+  // Fields of may_alias structs act like 'char' for TBAA purposes.
+  // FIXME: this should get propagated down through anonymous structs
+  // and unions.
+  if (mayAlias && LV.getTBAAAccessType())
+    LV.setTBAAAccessType(CGM.getTBAAMayAliasTypeInfo());
+
   return LV;
 }