Remove the experimental AliasAnalysis::getDependency interface, which

isn't a good level of abstraction for memdep. Instead, generalize
AliasAnalysis::alias and related interfaces with a new Location
class for describing a memory location. For now, this is the same
Pointer and Size as before, plus an additional field for a TBAA tag.

Also, introduce a fixed MD_tbaa metadata tag kind.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113858 91177308-0d34-0410-b5e6-96231b3b80d8

13 files changed, 256 insertions, 510 deletions

diff --git a/include/llvm/Analysis/AliasAnalysis.h b/include/llvm/Analysis/AliasAnalysis.h
index a03e0c8806..cae7addd3b 100644
--- a/include/llvm/Analysis/AliasAnalysis.h
+++ b/include/llvm/Analysis/AliasAnalysis.h
@@ -83,6 +83,22 @@ public:
   /// Alias Queries...
   ///
 
+  /// Location - A description of a memory location.
+  struct Location {
+    /// Ptr - The address of the start of the location.
+    const Value *Ptr;
+    /// Size - The size of the location.
+    unsigned Size;
+    /// TBAATag - The metadata node which describes the TBAA type of
+    /// the location, or null if there is no (unique) tag.
+    const MDNode *TBAATag;
+
+    explicit Location(const Value *P = 0,
+                      unsigned S = UnknownSize,
+                      const MDNode *N = 0)
+      : Ptr(P), Size(S), TBAATag(N) {}
+  };
+
   /// Alias analysis result - Either we know for sure that it does not alias, we
   /// know for sure it must alias, or we don't know anything: The two pointers
   /// _might_ alias.  This enum is designed so you can do things like:
@@ -98,27 +114,41 @@ public:
   /// Returns a Result indicating whether the two pointers are aliased to each
   /// other.  This is the interface that must be implemented by specific alias
   /// analysis implementations.
-  ///
-  virtual AliasResult alias(const Value *V1, unsigned V1Size,
-                            const Value *V2, unsigned V2Size);
+  virtual AliasResult alias(const Location &LocA, const Location &LocB);
 
-  /// alias - A convenience wrapper for the case where the sizes are unknown.
+  /// alias - A convenience wrapper.
+  AliasResult alias(const Value *V1, unsigned V1Size,
+                    const Value *V2, unsigned V2Size) {
+    return alias(Location(V1, V1Size), Location(V2, V2Size));
+  }
+
+  /// alias - A convenience wrapper.
   AliasResult alias(const Value *V1, const Value *V2) {
     return alias(V1, UnknownSize, V2, UnknownSize);
   }
 
   /// isNoAlias - A trivial helper function to check to see if the specified
   /// pointers are no-alias.
+  bool isNoAlias(const Location &LocA, const Location &LocB) {
+    return alias(LocA, LocB) == NoAlias;
+  }
+
+  /// isNoAlias - A convenience wrapper.
   bool isNoAlias(const Value *V1, unsigned V1Size,
                  const Value *V2, unsigned V2Size) {
-    return alias(V1, V1Size, V2, V2Size) == NoAlias;
+    return isNoAlias(Location(V1, V1Size), Location(V2, V2Size));
   }
 
-  /// pointsToConstantMemory - If the specified pointer is known to point into
-  /// constant global memory, return true.  This allows disambiguation of store
+  /// pointsToConstantMemory - If the specified memory location is known to be
+  /// constant, return true.  This allows disambiguation of store
   /// instructions from constant pointers.
   ///
-  virtual bool pointsToConstantMemory(const Value *P);
+  virtual bool pointsToConstantMemory(const Location &Loc);
+
+  /// pointsToConstantMemory - A convenient wrapper.
+  bool pointsToConstantMemory(const Value *P) {
+    return pointsToConstantMemory(Location(P));
+  }
 
   //===--------------------------------------------------------------------===//
   /// Simple mod/ref information...
@@ -220,55 +250,87 @@ public:
 
 
   /// getModRefInfo - Return information about whether or not an instruction may
-  /// read or write memory specified by the pointer operand.  An instruction
+  /// read or write the specified memory location.  An instruction
   /// that doesn't read or write memory may be trivially LICM'd for example.
   ModRefResult getModRefInfo(const Instruction *I,
-                             const Value *P, unsigned Size) {
+                             const Location &Loc) {
     switch (I->getOpcode()) {
-    case Instruction::VAArg:  return getModRefInfo((const VAArgInst*)I, P,Size);
-    case Instruction::Load:   return getModRefInfo((const LoadInst*)I, P, Size);
-    case Instruction::Store:  return getModRefInfo((const StoreInst*)I, P,Size);
-    case Instruction::Call:   return getModRefInfo((const CallInst*)I, P, Size);
-    case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,P,Size);
+    case Instruction::VAArg:  return getModRefInfo((const VAArgInst*)I, Loc);
+    case Instruction::Load:   return getModRefInfo((const LoadInst*)I,  Loc);
+    case Instruction::Store:  return getModRefInfo((const StoreInst*)I, Loc);
+    case Instruction::Call:   return getModRefInfo((const CallInst*)I,  Loc);
+    case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,Loc);
     default:                  return NoModRef;
     }
   }
 
+  /// getModRefInfo - A convenience wrapper.
+  ModRefResult getModRefInfo(const Instruction *I,
+                             const Value *P, unsigned Size) {
+    return getModRefInfo(I, Location(P, Size));
+  }
+
   /// getModRefInfo (for call sites) - Return whether information about whether
-  /// a particular call site modifies or reads the memory specified by the
-  /// pointer.
+  /// a particular call site modifies or reads the specified memory location.
   virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
-                                     const Value *P, unsigned Size);
+                                     const Location &Loc);
+
+  /// getModRefInfo (for call sites) - A convenience wrapper.
+  ModRefResult getModRefInfo(ImmutableCallSite CS,
+                             const Value *P, unsigned Size) {
+    return getModRefInfo(CS, Location(P, Size));
+  }
 
   /// getModRefInfo (for calls) - Return whether information about whether
-  /// a particular call modifies or reads the memory specified by the
-  /// pointer.
+  /// a particular call modifies or reads the specified memory location.
+  ModRefResult getModRefInfo(const CallInst *C, const Location &Loc) {
+    return getModRefInfo(ImmutableCallSite(C), Loc);
+  }
+
+  /// getModRefInfo (for calls) - A convenience wrapper.
   ModRefResult getModRefInfo(const CallInst *C, const Value *P, unsigned Size) {
-    return getModRefInfo(ImmutableCallSite(C), P, Size);
+    return getModRefInfo(C, Location(P, Size));
   }
 
   /// getModRefInfo (for invokes) - Return whether information about whether
-  /// a particular invoke modifies or reads the memory specified by the
-  /// pointer.
+  /// a particular invoke modifies or reads the specified memory location.
+  ModRefResult getModRefInfo(const InvokeInst *I,
+                             const Location &Loc) {
+    return getModRefInfo(ImmutableCallSite(I), Loc);
+  }
+
+  /// getModRefInfo (for invokes) - A convenience wrapper.
   ModRefResult getModRefInfo(const InvokeInst *I,
                              const Value *P, unsigned Size) {
-    return getModRefInfo(ImmutableCallSite(I), P, Size);
+    return getModRefInfo(I, Location(P, Size));
   }
 
   /// getModRefInfo (for loads) - Return whether information about whether
-  /// a particular load modifies or reads the memory specified by the
-  /// pointer.
-  ModRefResult getModRefInfo(const LoadInst *L, const Value *P, unsigned Size);
+  /// a particular load modifies or reads the specified memory location.
+  ModRefResult getModRefInfo(const LoadInst *L, const Location &Loc);
+
+  /// getModRefInfo (for loads) - A convenience wrapper.
+  ModRefResult getModRefInfo(const LoadInst *L, const Value *P, unsigned Size) {
+    return getModRefInfo(L, Location(P, Size));
+  }
 
   /// getModRefInfo (for stores) - Return whether information about whether
-  /// a particular store modifies or reads the memory specified by the
-  /// pointer.
-  ModRefResult getModRefInfo(const StoreInst *S, const Value *P, unsigned Size);
+  /// a particular store modifies or reads the specified memory location.
+  ModRefResult getModRefInfo(const StoreInst *S, const Location &Loc);
+
+  /// getModRefInfo (for stores) - A convenience wrapper.
+  ModRefResult getModRefInfo(const StoreInst *S, const Value *P, unsigned Size) {
+    return getModRefInfo(S, Location(P, Size));
+  }
 
   /// getModRefInfo (for va_args) - Return whether information about whether
-  /// a particular va_arg modifies or reads the memory specified by the
-  /// pointer.
-  ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, unsigned Size);
+  /// a particular va_arg modifies or reads the specified memory location.
+  ModRefResult getModRefInfo(const VAArgInst* I, const Location &Loc);
+
+  /// getModRefInfo (for va_args) - A convenience wrapper.
+  ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, unsigned Size) {
+    return getModRefInfo(I, Location(P, Size));
+  }
 
   /// getModRefInfo - Return information about whether two call sites may refer
   /// to the same set of memory locations.  See 
@@ -278,100 +340,30 @@ public:
                                      ImmutableCallSite CS2);
 
   //===--------------------------------------------------------------------===//
-  /// Dependence queries.
-  ///
-
-  /// DependenceResult - These are the return values for getDependence queries.
-  /// They are defined in terms of "memory", but they are also used to model
-  /// other side effects, such as I/O and volatility.
-  enum DependenceResult {
-    /// ReadThenRead - The instructions are ReadThenReadSome and the second
-    /// instruction reads from exactly the same memory read from by the first.
-    ReadThenRead,
-    
-    /// ReadThenReadSome - The instructions are Independent, both are read-only,
-    /// and the second instruction reads from a subset of the memory read from
-    /// by the first.
-    ReadThenReadSome,
-
-    /// Independent - Neither instruction reads from or writes to memory written
-    /// to by the other.  All enum values lower than this one are special cases
-    /// of Indepenent.
-    Independent,
-
-    /// WriteThenRead - The instructions are WriteThenReadSome and the second
-    /// instruction reads from exactly the same memory written by the first.
-    WriteThenRead,
-
-    /// WriteThenReadSome - The first instruction is write-only, the second
-    /// instruction is read-only, and the second only reads from memory
-    /// written to by the first.
-    WriteThenReadSome,
-
-    /// ReadThenWrite - The first instruction is read-only, the second
-    /// instruction is write-only, and the second wrotes to exactly the
-    /// same memory read from by the first.
-    ReadThenWrite,
-
-    /// WriteThenWrite - The instructions are WriteThenWriteSome, and the
-    /// second instruction writes to exactly the same memory written to by
-    /// the first.
-    WriteThenWrite,
-
-    /// WriteSomeThenWrite - Both instructions are write-only, and the second
-    /// instruction writes to a superset of the memory written to by the first.
-    WriteSomeThenWrite,
-
-    /// Unknown - The relationship between the instructions cannot be
-    /// determined or does not fit into any of the cases defined here.
-    Unknown
-  };
-
-  /// DependenceQueryFlags - Flags for refining dependence queries.
-  enum DependenceQueryFlags {
-    Default      = 0,
-    IgnoreLoads  = 1,
-    IgnoreStores = 2
-  };
-
-  /// getDependence - Determine the dependence relationship between the
-  /// instructions. This does not include "register" dependencies; it just
-  /// considers memory references and other side effects.
-  /// WARNING: This is an experimental interface.
-  DependenceResult getDependence(const Instruction *First,
-                                 const Instruction *Second) {
-    return getDependence(First, 0, Default, Second, 0, Default);
-  }
-
-  /// getDependence - Determine the dependence relationship between the
-  /// instructions. This does not include "register" dependencies; it just
-  /// considers memory references and other side effects.  This overload
-  /// has additional parameters to allow phi-translated addresses to be
-  /// specified, and additional flags to refine the query.
-  /// WARNING: This is an experimental interface.
-  virtual DependenceResult getDependence(const Instruction *First,
-                                         const Value *FirstPHITranslatedAddr,
-                                         DependenceQueryFlags FirstFlags,
-                                         const Instruction *Second,
-                                         const Value *SecondPHITranslatedAddr,
-                                         DependenceQueryFlags SecondFlags);
-
-  //===--------------------------------------------------------------------===//
   /// Higher level methods for querying mod/ref information.
   ///
 
   /// canBasicBlockModify - Return true if it is possible for execution of the
   /// specified basic block to modify the value pointed to by Ptr.
-  ///
-  bool canBasicBlockModify(const BasicBlock &BB, const Value *P, unsigned Size);
+  bool canBasicBlockModify(const BasicBlock &BB, const Location &Loc);
+
+  /// canBasicBlockModify - A convenience wrapper.
+  bool canBasicBlockModify(const BasicBlock &BB, const Value *P, unsigned Size){
+    return canBasicBlockModify(BB, Location(P, Size));
+  }
 
   /// canInstructionRangeModify - Return true if it is possible for the
   /// execution of the specified instructions to modify the value pointed to by
   /// Ptr.  The instructions to consider are all of the instructions in the
   /// range of [I1,I2] INCLUSIVE.  I1 and I2 must be in the same basic block.
-  ///
   bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
-                                 const Value *Ptr, unsigned Size);
+                                 const Location &Loc);
+
+  /// canInstructionRangeModify - A convenience wrapper.
+  bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
+                                 const Value *Ptr, unsigned Size) {
+    return canInstructionRangeModify(I1, I2, Location(Ptr, Size));
+  }
 
   //===--------------------------------------------------------------------===//
   /// Methods that clients should call when they transform the program to allow
@@ -401,17 +393,6 @@ public:
     copyValue(Old, New);
     deleteValue(Old);
   }
-
-protected:
-  /// getDependenceViaModRefInfo - Helper function for implementing getDependence
-  /// in implementations which already have getModRefInfo implementations.
-  DependenceResult getDependenceViaModRefInfo(const Instruction *First,
-                                              const Value *FirstPHITranslatedAddr,
-                                              DependenceQueryFlags FirstFlags,
-                                              const Instruction *Second,
-                                              const Value *SecondPHITranslatedAddr,
-                                              DependenceQueryFlags SecondFlags);
-
 };
 
 /// isNoAliasCall - Return true if this pointer is returned by a noalias
diff --git a/include/llvm/Analysis/LibCallAliasAnalysis.h b/include/llvm/Analysis/LibCallAliasAnalysis.h
index c9adf3f36a..7d7782ab7c 100644
--- a/include/llvm/Analysis/LibCallAliasAnalysis.h
+++ b/include/llvm/Analysis/LibCallAliasAnalysis.h
@@ -36,7 +36,7 @@ namespace llvm {
     ~LibCallAliasAnalysis();
     
     ModRefResult getModRefInfo(ImmutableCallSite CS,
-                               const Value *P, unsigned Size);
+                               const Location &Loc);
     
     ModRefResult getModRefInfo(ImmutableCallSite CS1,
                                ImmutableCallSite CS2) {
@@ -64,7 +64,7 @@ namespace llvm {
   private:
     ModRefResult AnalyzeLibCallDetails(const LibCallFunctionInfo *FI,
                                        ImmutableCallSite CS,
-                                       const Value *P, unsigned Size);
+                                       const Location &Loc);
   };
 }  // End of llvm namespace
 
diff --git a/include/llvm/Analysis/LibCallSemantics.h b/include/llvm/Analysis/LibCallSemantics.h
index 31d7cc56ce..f5a9e96cbd 100644
--- a/include/llvm/Analysis/LibCallSemantics.h
+++ b/include/llvm/Analysis/LibCallSemantics.h
@@ -48,7 +48,7 @@ namespace llvm {
       Yes, No, Unknown
     };
     LocResult (*isLocation)(ImmutableCallSite CS,
-                            const Value *Ptr, unsigned Size);
+                            const AliasAnalysis::Location &Loc);
   };
   
   /// LibCallFunctionInfo - Each record in the array of FunctionInfo structs
diff --git a/include/llvm/LLVMContext.h b/include/llvm/LLVMContext.h
index 8abf277772..e5b77777d9 100644
--- a/include/llvm/LLVMContext.h
+++ b/include/llvm/LLVMContext.h
@@ -37,7 +37,8 @@ public:
   // Pinned metadata names, which always have the same value.  This is a
   // compile-time performance optimization, not a correctness optimization.
   enum {
-    MD_dbg = 0   // "dbg"
+    MD_dbg = 0,  // "dbg"
+    MD_tbaa = 1  // "tbaa"
   };
   
   /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index 93597cab22..b9cd5a6920 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -30,6 +30,7 @@
 #include "llvm/Function.h"
 #include "llvm/IntrinsicInst.h"
 #include "llvm/Instructions.h"
+#include "llvm/LLVMContext.h"
 #include "llvm/Type.h"
 #include "llvm/Target/TargetData.h"
 using namespace llvm;
@@ -43,15 +44,14 @@ char AliasAnalysis::ID = 0;
 //===----------------------------------------------------------------------===//
 
 AliasAnalysis::AliasResult
-AliasAnalysis::alias(const Value *V1, unsigned V1Size,
-                     const Value *V2, unsigned V2Size) {
+AliasAnalysis::alias(const Location &LocA, const Location &LocB) {
   assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
-  return AA->alias(V1, V1Size, V2, V2Size);
+  return AA->alias(LocA, LocB);
 }
 
-bool AliasAnalysis::pointsToConstantMemory(const Value *P) {
+bool AliasAnalysis::pointsToConstantMemory(const Location &Loc) {
   assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
-  return AA->pointsToConstantMemory(P);
+  return AA->pointsToConstantMemory(Loc);
 }
 
 void AliasAnalysis::deleteValue(Value *V) {
@@ -66,7 +66,7 @@ void AliasAnalysis::copyValue(Value *From, Value *To) {
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
-                             const Value *P, unsigned Size) {
+                             const Location &Loc) {
   // Don't assert AA because BasicAA calls us in order to make use of the
   // logic here.
 
@@ -81,7 +81,7 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
     bool doesAlias = false;
     for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
          AI != AE; ++AI)
-      if (!isNoAlias(*AI, ~0U, P, Size)) {
+      if (!isNoAlias(Location(*AI), Loc)) {
         doesAlias = true;
         break;
       }
@@ -90,9 +90,9 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
       return NoModRef;
   }
 
-  // If P points to a constant memory location, the call definitely could not
+  // If Loc is a constant memory location, the call definitely could not
   // modify the memory location.
-  if ((Mask & Mod) && pointsToConstantMemory(P))
+  if ((Mask & Mod) && pointsToConstantMemory(Loc))
     Mask = ModRefResult(Mask & ~Mod);
 
   // If this is BasicAA, don't forward.
@@ -100,7 +100,7 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
 
   // Otherwise, fall back to the next AA in the chain. But we can merge
   // in any mask we've managed to compute.
-  return ModRefResult(AA->getModRefInfo(CS, P, Size) & Mask);
+  return ModRefResult(AA->getModRefInfo(CS, Loc) & Mask);
 }
 
 AliasAnalysis::ModRefResult
@@ -188,31 +188,22 @@ AliasAnalysis::getModRefBehavior(const Function *F) {
   return AA->getModRefBehavior(F);
 }
 
-AliasAnalysis::DependenceResult
-AliasAnalysis::getDependence(const Instruction *First,
-                             const Value *FirstPHITranslatedAddr,
-                             DependenceQueryFlags FirstFlags,
-                             const Instruction *Second,
-                             const Value *SecondPHITranslatedAddr,
-                             DependenceQueryFlags SecondFlags) {
-  assert(AA && "AA didn't call InitializeAliasAnalyais in its run method!");
-  return AA->getDependence(First, FirstPHITranslatedAddr, FirstFlags,
-                           Second, SecondPHITranslatedAddr, SecondFlags);
-}
-
 //===----------------------------------------------------------------------===//
 // AliasAnalysis non-virtual helper method implementation
 //===----------------------------------------------------------------------===//
 
 AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(const LoadInst *L, const Value *P, unsigned Size) {
+AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) {
   // Be conservative in the face of volatile.
   if (L->isVolatile())
     return ModRef;
 
   // If the load address doesn't alias the given address, it doesn't read
   // or write the specified memory.
-  if (!alias(L->getOperand(0), getTypeStoreSize(L->getType()), P, Size))
+  if (!alias(Location(L->getOperand(0),
+                      getTypeStoreSize(L->getType()),
+                      L->getMetadata(LLVMContext::MD_tbaa)),
+             Loc))
     return NoModRef;
 
   // Otherwise, a load just reads.
@@ -220,20 +211,22 @@ AliasAnalysis::getModRefInfo(const LoadInst *L, const Value *P, unsigned Size) {
 }
 
 AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(const StoreInst *S, const Value *P, unsigned Size) {
+AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) {
   // Be conservative in the face of volatile.
   if (S->isVolatile())
     return ModRef;
 
   // If the store address cannot alias the pointer in question, then the
   // specified memory cannot be modified by the store.
-  if (!alias(S->getOperand(1),
-             getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
+  if (!alias(Location(S->getOperand(1),
+                      getTypeStoreSize(S->getOperand(0)->getType()),
+                      S->getMetadata(LLVMContext::MD_tbaa)),
+             Loc))
     return NoModRef;
 
   // If the pointer is a pointer to constant memory, then it could not have been
   // modified by this store.
-  if (pointsToConstantMemory(P))
+  if (pointsToConstantMemory(Loc))
     return NoModRef;
 
   // Otherwise, a store just writes.
@@ -241,240 +234,24 @@ AliasAnalysis::getModRefInfo(const StoreInst *S, const Value *P, unsigned Size)
 }
 
 AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(const VAArgInst *V, const Value *P, unsigned Size) {
+AliasAnalysis::getModRefInfo(const VAArgInst *V, const Location &Loc) {
   // If the va_arg address cannot alias the pointer in question, then the
   // specified memory cannot be accessed by the va_arg.
-  if (!alias(V->getOperand(0), UnknownSize, P, Size))
+  if (!alias(Location(V->getOperand(0),
+                      UnknownSize,
+                      V->getMetadata(LLVMContext::MD_tbaa)),
+             Loc))
     return NoModRef;
 
   // If the pointer is a pointer to constant memory, then it could not have been
   // modified by this va_arg.
-  if (pointsToConstantMemory(P))
+  if (pointsToConstantMemory(Loc))
     return NoModRef;
 
   // Otherwise, a va_arg reads and writes.
   return ModRef;
 }
 
-AliasAnalysis::DependenceResult
-AliasAnalysis::getDependenceViaModRefInfo(const Instruction *First,
-                                          const Value *FirstPHITranslatedAddr,
-                                          DependenceQueryFlags FirstFlags,
-                                          const Instruction *Second,
-                                          const Value *SecondPHITranslatedAddr,
-                                          DependenceQueryFlags SecondFlags) {
-  if (const LoadInst *L = dyn_cast<LoadInst>(First)) {
-    // Be over-conservative with volatile for now.
-    if (L->isVolatile())
-      return Unknown;
-
-    // If we don't have a phi-translated address, use the actual one.
-    if (!FirstPHITranslatedAddr)
-      FirstPHITranslatedAddr = L->getPointerOperand();
-
-    // Forward this query to getModRefInfo.
-    switch (getModRefInfo(Second,
-                          FirstPHITranslatedAddr,
-                          getTypeStoreSize(L->getType()))) {
-    case NoModRef:
-      // Second doesn't reference First's memory, so they're independent.
-      return Independent;
-
-    case Ref:
-      // Second only reads from the memory read from by First. If it
-      // also writes to any other memory, be conservative.
-      if (Second->mayWriteToMemory())
-        return Unknown;
-
-      // If it's loading the same size from the same address, we can
-      // give a more precise result.
-      if (const LoadInst *SecondL = dyn_cast<LoadInst>(Second)) {
-        // If we don't have a phi-translated address, use the actual one.
-        if (!SecondPHITranslatedAddr)
-          SecondPHITranslatedAddr = SecondL->getPointerOperand();
-
-        unsigned LSize = getTypeStoreSize(L->getType());
-        unsigned SecondLSize = getTypeStoreSize(SecondL->getType());
-        if (alias(FirstPHITranslatedAddr, LSize,
-                  SecondPHITranslatedAddr, SecondLSize) ==
-            MustAlias) {
-          // If the loads are the same size, it's ReadThenRead.
-          if (LSize == SecondLSize)
-            return ReadThenRead;
-
-          // If the second load is smaller, it's only ReadThenReadSome.
-          if (LSize > SecondLSize)
-            return ReadThenReadSome;
-        }
-      }
-
-      // Otherwise it's just two loads.
-      return Independent;
-
-    case Mod:
-      // Second only writes to the memory read from by First. If it
-      // also reads from any other memory, be conservative.
-      if (Second->mayReadFromMemory())
-        return Unknown;
-
-      // If it's storing the same size to the same address, we can
-      // give a more precise result.
-      if (const StoreInst *SecondS = dyn_cast<StoreInst>(Second)) {
-        // If we don't have a phi-translated address, use the actual one.
-        if (!SecondPHITranslatedAddr)
-          SecondPHITranslatedAddr = SecondS->getPointerOperand();
-
-        unsigned LSize = getTypeStoreSize(L->getType());
-        unsigned SecondSSize = getTypeStoreSize(SecondS->getType());
-        if (alias(FirstPHITranslatedAddr, LSize,
-                  SecondPHITranslatedAddr, SecondSSize) ==
-            MustAlias) {
-          // If the load and the store are the same size, it's ReadThenWrite.
-          if (LSize == SecondSSize)
-            return ReadThenWrite;
-        }
-      }
-
-      // Otherwise we don't know if it could be writing to other memory.
-      return Unknown;
-
-    case ModRef:
-      // Second reads and writes to the memory read from by First.
-      // We don't have a way to express that.
-      return Unknown;
-    }
-
-  } else if (const StoreInst *S = dyn_cast<StoreInst>(First)) {
-    // Be over-conservative with volatile for now.
-    if (S->isVolatile())
-      return Unknown;
-
-    // If we don't have a phi-translated address, use the actual one.
-    if (!FirstPHITranslatedAddr)
-      FirstPHITranslatedAddr = S->getPointerOperand();
-
-    // Forward this query to getModRefInfo.
-    switch (getModRefInfo(Second,
-                          FirstPHITranslatedAddr,
-                          getTypeStoreSize(S->getValueOperand()->getType()))) {
-    case NoModRef:
-      // Second doesn't reference First's memory, so they're independent.
-      return Independent;
-
-    case Ref:
-      // Second only reads from the memory written to by First. If it
-      // also writes to any other memory, be conservative.
-      if (Second->mayWriteToMemory())
-        return Unknown;
-
-      // If it's loading the same size from the same address, we can
-      // give a more precise result.
-      if (const LoadInst *SecondL = dyn_cast<LoadInst>(Second)) {
-        // If we don't have a phi-translated address, use the actual one.
-        if (!SecondPHITranslatedAddr)
-          SecondPHITranslatedAddr = SecondL->getPointerOperand();
-
-        unsigned SSize = getTypeStoreSize(S->getValueOperand()->getType());
-        unsigned SecondLSize = getTypeStoreSize(SecondL->getType());
-        if (alias(FirstPHITranslatedAddr, SSize,
-                  SecondPHITranslatedAddr, SecondLSize) ==
-            MustAlias) {
-          // If the store and the load are the same size, it's WriteThenRead.
-          if (SSize == SecondLSize)
-            return WriteThenRead;
-
-          // If the load is smaller, it's only WriteThenReadSome.
-          if (SSize > SecondLSize)
-            return WriteThenReadSome;
-        }
-      }
-
-      // Otherwise we don't know if it could be reading from other memory.
-      return Unknown;
-
-    case Mod:
-      // Second only writes to the memory written to by First. If it
-      // also reads from any other memory, be conservative.
-      if (Second->mayReadFromMemory())
-        return Unknown;
-
-      // If it's storing the same size to the same address, we can
-      // give a more precise result.
-      if (const StoreInst *SecondS = dyn_cast<StoreInst>(Second)) {
-        // If we don't have a phi-translated address, use the actual one.
-        if (!SecondPHITranslatedAddr)
-          SecondPHITranslatedAddr = SecondS->getPointerOperand();
-
-        unsigned SSize = getTypeStoreSize(S->getValueOperand()->getType());
-        unsigned SecondSSize = getTypeStoreSize(SecondS->getType());
-        if (alias(FirstPHITranslatedAddr, SSize,
-                  SecondPHITranslatedAddr, SecondSSize) ==
-            MustAlias) {
-          // If the stores are the same size, it's WriteThenWrite.
-          if (SSize == SecondSSize)
-            return WriteThenWrite;
-
-          // If the second store is larger, it's only WriteSomeThenWrite.
-          if (SSize < SecondSSize)
-            return WriteSomeThenWrite;
-        }
-      }
-
-      // Otherwise we don't know if it could be writing to other memory.
-      return Unknown;
-
-    case ModRef:
-      // Second reads and writes to the memory written to by First.
-      // We don't have a way to express that.
-      return Unknown;
-    }
-
-  } else if (const VAArgInst *V = dyn_cast<VAArgInst>(First)) {
-    // If we don't have a phi-translated address, use the actual one.
-    if (!FirstPHITranslatedAddr)
-      FirstPHITranslatedAddr = V->getPointerOperand();
-
-    // Forward this query to getModRefInfo.
-    if (getModRefInfo(Second, FirstPHITranslatedAddr, UnknownSize) == NoModRef)
-      // Second doesn't reference First's memory, so they're independent.
-      return Independent;
-
-  } else if (ImmutableCallSite FirstCS = cast<Value>(First)) {
-    assert(!FirstPHITranslatedAddr &&
-           !SecondPHITranslatedAddr &&
-           "PHI translation with calls not supported yet!");
-
-    // If both instructions are calls/invokes we can use the two-callsite
-    // form of getModRefInfo.
-    if (ImmutableCallSite SecondCS = cast<Value>(Second))
-      // getModRefInfo's arguments are backwards from intuition.
-      switch (getModRefInfo(SecondCS, FirstCS)) {
-      case NoModRef:
-        // Second doesn't reference First's memory, so they're independent.
-        return Independent;
-
-      case Ref:
-        // If they're both read-only, there's no dependence.
-        if (FirstCS.onlyReadsMemory() && SecondCS.onlyReadsMemory())
-          return Independent;
-
-        // Otherwise it's not obvious what we can do here.
-        return Unknown;
-
-      case Mod:
-        // It's not obvious what we can do here.
-        return Unknown;
-
-      case ModRef:
-        // I know, right?
-        return Unknown;
-      }
-  }
-
-  // For anything else, be conservative.
-  return Unknown;
-}
-
 AliasAnalysis::ModRefBehavior
 AliasAnalysis::getIntrinsicModRefBehavior(unsigned iid) {
 #define GET_INTRINSIC_MODREF_BEHAVIOR
@@ -514,8 +291,8 @@ unsigned AliasAnalysis::getTypeStoreSize(const Type *Ty) {
 /// specified basic block to modify the value pointed to by Ptr.
 ///
 bool AliasAnalysis::canBasicBlockModify(const BasicBlock &BB,
-                                        const Value *Ptr, unsigned Size) {
-  return canInstructionRangeModify(BB.front(), BB.back(), Ptr, Size);
+                                        const Location &Loc) {
+  return canInstructionRangeModify(BB.front(), BB.back(), Loc);
 }
 
 /// canInstructionRangeModify - Return true if it is possible for the execution
@@ -525,7 +302,7 @@ bool AliasAnalysis::canBasicBlockModify(const BasicBlock &BB,
 ///
 bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
                                               const Instruction &I2,
-                                              const Value *Ptr, unsigned Size) {
+                                              const Location &Loc) {
   assert(I1.getParent() == I2.getParent() &&
          "Instructions not in same basic block!");
   BasicBlock::const_iterator I = &I1;
@@ -533,7 +310,7 @@ bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
   ++E;  // Convert from inclusive to exclusive range.
 
   for (; I != E; ++I) // Check every instruction in range
-    if (getModRefInfo(I, Ptr, Size) & Mod)
+    if (getModRefInfo(I, Loc) & Mod)
       return true;
   return false;
 }
diff --git a/lib/Analysis/AliasAnalysisCounter.cpp b/lib/Analysis/AliasAnalysisCounter.cpp
index b17804186a..48f7a9f223 100644
--- a/lib/Analysis/AliasAnalysisCounter.cpp
+++ b/lib/Analysis/AliasAnalysisCounter.cpp
@@ -94,17 +94,16 @@ namespace {
     }
     
     // FIXME: We could count these too...
-    bool pointsToConstantMemory(const Value *P) {
-      return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
+    bool pointsToConstantMemory(const Location &Loc) {
+      return getAnalysis<AliasAnalysis>().pointsToConstantMemory(Loc);
     }
 
     // Forwarding functions: just delegate to a real AA implementation, counting
     // the number of responses...
-    AliasResult alias(const Value *V1, unsigned V1Size,
-                      const Value *V2, unsigned V2Size);
+    AliasResult alias(const Location &LocA, const Location &LocB);
 
     ModRefResult getModRefInfo(ImmutableCallSite CS,
-                               const Value *P, unsigned Size);
+                               const Location &Loc);
     ModRefResult getModRefInfo(ImmutableCallSite CS1,
                                ImmutableCallSite CS2) {
       return AliasAnalysis::getModRefInfo(CS1,CS2);
@@ -121,9 +120,8 @@ ModulePass *llvm::createAliasAnalysisCounterPass() {
 }
 
 AliasAnalysis::AliasResult
-AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
-                            const Value *V2, unsigned V2Size) {
-  AliasResult R = getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
+AliasAnalysisCounter::alias(const Location &LocA, const Location &LocB) {
+  AliasResult R = getAnalysis<AliasAnalysis>().alias(LocA, LocB);
 
   const char *AliasString;
   switch (R) {
@@ -135,11 +133,11 @@ AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
 
   if (PrintAll || (PrintAllFailures && R == MayAlias)) {
     errs() << AliasString << ":\t";
-    errs() << "[" << V1Size << "B] ";
-    WriteAsOperand(errs(), V1, true, M);
+    errs() << "[" << LocA.Size << "B] ";
+    WriteAsOperand(errs(), LocA.Ptr, true, M);
     errs() << ", ";
-    errs() << "[" << V2Size << "B] ";
-    WriteAsOperand(errs(), V2, true, M);
+    errs() << "[" << LocB.Size << "B] ";
+    WriteAsOperand(errs(), LocB.Ptr, true, M);
     errs() << "\n";
   }
 
@@ -148,8 +146,8 @@ AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
 
 AliasAnalysis::ModRefResult
 AliasAnalysisCounter::getModRefInfo(ImmutableCallSite CS,
-                                    const Value *P, unsigned Size) {
-  ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, P, Size);
+                                    const Location &Loc) {
+  ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, Loc);
 
   const char *MRString;
   switch (R) {
@@ -162,8 +160,8 @@ AliasAnalysisCounter::getModRefInfo(ImmutableCallSite CS,
 
   if (PrintAll || (PrintAllFailures && R == ModRef)) {
     errs() << MRString << ":  Ptr: ";
-    errs() << "[" << Size << "B] ";
-    WriteAsOperand(errs(), P, true, M);
+    errs() << "[" << Loc.Size << "B] ";
+    WriteAsOperand(errs(), Loc.Ptr, true, M);
     errs() << "\t<->" << *CS.getInstruction() << '\n';
   }
   return R;
diff --git a/lib/Analysis/AliasDebugger.cpp b/lib/Analysis/AliasDebugger.cpp
index b9fe64608c..82e705dd1c 100644
--- a/lib/Analysis/AliasDebugger.cpp
+++ b/lib/Analysis/AliasDebugger.cpp
@@ -92,17 +92,18 @@ namespace {
     //------------------------------------------------
     // Implement the AliasAnalysis API
     //
-    AliasResult alias(const Value *V1, unsigned V1Size,
-                      const Value *V2, unsigned V2Size) {
-      assert(Vals.find(V1) != Vals.end() && "Never seen value in AA before");
-      assert(Vals.find(V2) != Vals.end() && "Never seen value in AA before");    
-      return AliasAnalysis::alias(V1, V1Size, V2, V2Size);
+    AliasResult alias(const Location &LocA, const Location &LocB) {
+      assert(Vals.find(LocA.Ptr) != Vals.end() &&
+             "Never seen value in AA before");
+      assert(Vals.find(LocB.Ptr) != Vals.end() &&
+             "Never seen value in AA before");
+      return AliasAnalysis::alias(LocA, LocB);
     }
 
     ModRefResult getModRefInfo(ImmutableCallSite CS,
-                               const Value *P, unsigned Size) {
-      assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
-      return AliasAnalysis::getModRefInfo(CS, P, Size);
+                               const Location &Loc) {
+      assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before");
+      return AliasAnalysis::getModRefInfo(CS, Loc);
     }
 
     ModRefResult getModRefInfo(ImmutableCallSite CS1,
@@ -110,9 +111,9 @@ namespace {
       return AliasAnalysis::getModRefInfo(CS1,CS2);
     }
     
-    bool pointsToConstantMemory(const Value *P) {
-      assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
-      return AliasAnalysis::pointsToConstantMemory(P);
+    bool pointsToConstantMemory(const Location &Loc) {
+      assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before");
+      return AliasAnalysis::pointsToConstantMemory(Loc);
     }
 
     virtual void deleteValue(Value *V) {
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 354e66df0c..69a1c0c772 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -22,6 +22,7 @@
 #include "llvm/GlobalVariable.h"
 #include "llvm/Instructions.h"
 #include "llvm/IntrinsicInst.h"
+#include "llvm/LLVMContext.h"
 #include "llvm/Operator.h"
 #include "llvm/Pass.h"
 #include "llvm/Analysis/CaptureTracking.h"
@@ -149,8 +150,7 @@ namespace {
       TD = getAnalysisIfAvailable<TargetData>();
     }
 
-    virtual AliasResult alias(const Value *V1, unsigned V1Size,
-                              const Value *V2, unsigned V2Size) {
+    virtual AliasResult alias(const Location &LocA, const Location &LocB) {
       return MayAlias;
     }
 
@@ -161,9 +161,9 @@ namespace {
       return UnknownModRefBehavior;
     }
 
-    virtual bool pointsToConstantMemory(const Value *P) { return false; }
+    virtual bool pointsToConstantMemory(const Location &Loc) { return false; }
     virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
-                                       const Value *P, unsigned Size) {
+                                       const Location &Loc) {
       return ModRef;
     }
     virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
@@ -171,15 +171,6 @@ namespace {
       return ModRef;
     }
 
-    virtual DependenceResult getDependence(const Instruction *First,
-                                           const Value *FirstPHITranslatedAddr,
-                                           DependenceQueryFlags FirstFlags,
-                                           const Instruction *Second,
-                                           const Value *SecondPHITranslatedAddr,
-                                           DependenceQueryFlags SecondFlags) {
-      return Unknown;
-    }
-
     virtual void deleteValue(Value *V) {}
     virtual void copyValue(Value *From, Value *To) {}
     
@@ -501,18 +492,18 @@ namespace {
     static char ID; // Class identification, replacement for typeinfo
     BasicAliasAnalysis() : NoAA(ID) {}
 
-    virtual AliasResult alias(const Value *V1, unsigned V1Size,
-                              const Value *V2, unsigned V2Size) {
+    virtual AliasResult alias(const Location &LocA,
+                              const Location &LocB) {
       assert(Visited.empty() && "Visited must be cleared after use!");
-      assert(notDifferentParent(V1, V2) &&
+      assert(notDifferentParent(LocA.Ptr, LocB.Ptr) &&
              "BasicAliasAnalysis doesn't support interprocedural queries.");
-      AliasResult Alias = aliasCheck(V1, V1Size, V2, V2Size);
+      AliasResult Alias = aliasCheck(LocA.Ptr, LocA.Size, LocB.Ptr, LocB.Size);
       Visited.clear();
       return Alias;
     }
 
     virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
-                                       const Value *P, unsigned Size);
+                                       const Location &Loc);
 
     virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
                                        ImmutableCallSite CS2) {
@@ -522,7 +513,7 @@ namespace {
 
     /// pointsToConstantMemory - Chase pointers until we find a (constant
     /// global) or not.
-    virtual bool pointsToConstantMemory(const Value *P);
+    virtual bool pointsToConstantMemory(const Location &Loc);
 
     /// getModRefBehavior - Return the behavior when calling the given
     /// call site.
@@ -532,13 +523,6 @@ namespace {
     /// For use when the call site is not known.
     virtual ModRefBehavior getModRefBehavior(const Function *F);
 
-    virtual DependenceResult getDependence(const Instruction *First,
-                                           const Value *FirstPHITranslatedAddr,
-                                           DependenceQueryFlags FirstFlags,
-                                           const Instruction *Second,
-                                           const Value *SecondPHITranslatedAddr,
-                                           DependenceQueryFlags SecondFlags);
-
     /// getAdjustedAnalysisPointer - This method is used when a pass implements
     /// an analysis interface through multiple inheritance.  If needed, it
     /// should override this to adjust the this pointer as needed for the
@@ -586,15 +570,15 @@ ImmutablePass *llvm::createBasicAliasAnalysisPass() {
 
 /// pointsToConstantMemory - Chase pointers until we find a (constant
 /// global) or not.
-bool BasicAliasAnalysis::pointsToConstantMemory(const Value *P) {
+bool BasicAliasAnalysis::pointsToConstantMemory(const Location &Loc) {
   if (const GlobalVariable *GV = 
-        dyn_cast<GlobalVariable>(P->getUnderlyingObject()))
+        dyn_cast<GlobalVariable>(Loc.Ptr->getUnderlyingObject()))
     // Note: this doesn't require GV to be "ODR" because it isn't legal for a
     // global to be marked constant in some modules and non-constant in others.
     // GV may even be a declaration, not a definition.
     return GV->isConstant();
 
-  return NoAA::pointsToConstantMemory(P);
+  return NoAA::pointsToConstantMemory(Loc);
 }
 
 /// getModRefBehavior - Return the behavior when calling the given call site.
@@ -636,13 +620,13 @@ BasicAliasAnalysis::getModRefBehavior(const Function *F) {
 /// simple "address taken" analysis on local objects.
 AliasAnalysis::ModRefResult
 BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
-                                  const Value *P, unsigned Size) {
-  assert(notDifferentParent(CS.getInstruction(), P) &&
+                                  const Location &Loc) {
+  assert(notDifferentParent(CS.getInstruction(), Loc.Ptr) &&
          "AliasAnalysis query involving multiple functions!");
 
-  const Value *Object = P->getUnderlyingObject();
+  const Value *Object = Loc.Ptr->getUnderlyingObject();
   
-  // If this is a tail call and P points to a stack location, we know that
+  // If this is a tail call and Loc.Ptr points to a stack location, we know that
   // the tail call cannot access or modify the local stack.
   // We cannot exclude byval arguments here; these belong to the caller of
   // the current function not to the current function, and a tail callee
@@ -666,11 +650,11 @@ BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
           !CS.paramHasAttr(ArgNo+1, Attribute::NoCapture))
         continue;
       
-      // If  this is a no-capture pointer argument, see if we can tell that it
+      // If this is a no-capture pointer argument, see if we can tell that it
       // is impossible to alias the pointer we're checking.  If not, we have to
       // assume that the call could touch the pointer, even though it doesn't
       // escape.
-      if (!isNoAlias(cast<Value>(CI), UnknownSize, P, UnknownSize)) {
+      if (!isNoAlias(Location(cast<Value>(CI)), Loc)) {
         PassedAsArg = true;
         break;
       }
@@ -692,8 +676,8 @@ BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
         Len = LenCI->getZExtValue();
       Value *Dest = II->getArgOperand(0);
       Value *Src = II->getArgOperand(1);
-      if (isNoAlias(Dest, Len, P, Size)) {
-        if (isNoAlias(Src, Len, P, Size))
+      if (isNoAlias(Location(Dest, Len), Loc)) {
+        if (isNoAlias(Location(Src, Len), Loc))
           return NoModRef;
         return Ref;
       }
@@ -705,7 +689,7 @@ BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
       if (ConstantInt *LenCI = dyn_cast<ConstantInt>(II->getArgOperand(2))) {
         unsigned Len = LenCI->getZExtValue();
         Value *Dest = II->getArgOperand(0);
-        if (isNoAlias(Dest, Len, P, Size))
+        if (isNoAlias(Location(Dest, Len), Loc))
           return NoModRef;
       }
       break;
@@ -724,7 +708,8 @@ BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
       if (TD) {
         Value *Op1 = II->getArgOperand(0);
         unsigned Op1Size = TD->getTypeStoreSize(Op1->getType());
-        if (isNoAlias(Op1, Op1Size, P, Size))
+        MDNode *Tag = II->getMetadata(LLVMContext::MD_tbaa);
+        if (isNoAlias(Location(Op1, Op1Size, Tag), Loc))
           return NoModRef;
       }
       break;
@@ -733,33 +718,27 @@ BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
     case Intrinsic::invariant_start: {
       unsigned PtrSize =
         cast<ConstantInt>(II->getArgOperand(0))->getZExtValue();
-      if (isNoAlias(II->getArgOperand(1), PtrSize, P, Size))
+      if (isNoAlias(Location(II->getArgOperand(1),
+                             PtrSize,
+                             II->getMetadata(LLVMContext::MD_tbaa)),
+                    Loc))
         return NoModRef;
       break;
     }
     case Intrinsic::invariant_end: {
       unsigned PtrSize =
         cast<ConstantInt>(II->getArgOperand(1))->getZExtValue();
-      if (isNoAlias(II->getArgOperand(2), PtrSize, P, Size))
+      if (isNoAlias(Location(II->getArgOperand(2),
+                             PtrSize,
+                             II->getMetadata(LLVMContext::MD_tbaa)),
+                    Loc))
         return NoModRef;
       break;
     }
     }
 
   // The AliasAnalysis base class has some smarts, lets use them.
-  return AliasAnalysis::getModRefInfo(CS, P, Size);
-}
-
-AliasAnalysis::DependenceResult
-BasicAliasAnalysis::getDependence(const Instruction *First,
-                                  const Value *FirstPHITranslatedAddr,
-                                  DependenceQueryFlags FirstFlags,
-                                  const Instruction *Second,
-                                  const Value *SecondPHITranslatedAddr,
-                                  DependenceQueryFlags SecondFlags) {
-  // We don't have anything special to say yet.
-  return getDependenceViaModRefInfo(First, FirstPHITranslatedAddr, FirstFlags,
-                                    Second, SecondPHITranslatedAddr, SecondFlags);
+  return AliasAnalysis::getModRefInfo(CS, Loc);
 }
 
 /// aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a GEP instruction
@@ -1103,7 +1082,7 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, unsigned V1Size,
   if (const SelectInst *S1 = dyn_cast<SelectInst>(V1))
     return aliasSelect(S1, V1Size, V2, V2Size);
 
-  return NoAA::alias(V1, V1Size, V2, V2Size);
+  return NoAA::alias(Location(V1, V1Size), Location(V2, V2Size));
 }
 
 // Make sure that anything that uses AliasAnalysis pulls in this file.
diff --git a/lib/Analysis/IPA/GlobalsModRef.cpp b/lib/Analysis/IPA/GlobalsModRef.cpp
index 6759b0afdc..8622c1137c 100644
--- a/lib/Analysis/IPA/GlobalsModRef.cpp
+++ b/lib/Analysis/IPA/GlobalsModRef.cpp
@@ -106,10 +106,9 @@ namespace {
     //------------------------------------------------
     // Implement the AliasAnalysis API
     //
-    AliasResult alias(const Value *V1, unsigned V1Size,
-                      const Value *V2, unsigned V2Size);
+    AliasResult alias(const Location &LocA, const Location &LocB);
     ModRefResult getModRefInfo(ImmutableCallSite CS,
-                               const Value *P, unsigned Size);
+                               const Location &Loc);
     ModRefResult getModRefInfo(ImmutableCallSite CS1,
                                ImmutableCallSite CS2) {
       return AliasAnalysis::getModRefInfo(CS1, CS2);
@@ -476,11 +475,11 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
 /// other is some random pointer, we know there cannot be an alias, because the
 /// address of the global isn't taken.
 AliasAnalysis::AliasResult
-GlobalsModRef::alias(const Value *V1, unsigned V1Size,
-                     const Value *V2, unsigned V2Size) {
+GlobalsModRef::alias(const Location &LocA,
+                     const Location &LocB) {
   // Get the base object these pointers point to.
-  const Value *UV1 = V1->getUnderlyingObject();
-  const Value *UV2 = V2->getUnderlyingObject();
+  const Value *UV1 = LocA.Ptr->getUnderlyingObject();
+  const Value *UV2 = LocB.Ptr->getUnderlyingObject();
 
   // If either of the underlying values is a global, they may be non-addr-taken
   // globals, which we can answer queries about.
@@ -528,17 +527,18 @@ GlobalsModRef::alias(const Value *V1, unsigned V1Size,
   if ((GV1 || GV2) && GV1 != GV2)
     return NoAlias;
 
-  return AliasAnalysis::alias(V1, V1Size, V2, V2Size);
+  return AliasAnalysis::alias(LocA, LocB);
 }
 
 AliasAnalysis::ModRefResult
 GlobalsModRef::getModRefInfo(ImmutableCallSite CS,
-                             const Value *P, unsigned Size) {
+                             const Location &Loc) {
   unsigned Known = ModRef;
 
   // If we are asking for mod/ref info of a direct call with a pointer to a
   // global we are tracking, return information if we have it.
-  if (const GlobalValue *GV = dyn_cast<GlobalValue>(P->getUnderlyingObject()))
+  if (const GlobalValue *GV =
+        dyn_cast<GlobalValue>(Loc.Ptr->getUnderlyingObject()))
     if (GV->hasLocalLinkage())
       if (const Function *F = CS.getCalledFunction())
         if (NonAddressTakenGlobals.count(GV))
@@ -547,7 +547,7 @@ GlobalsModRef::getModRefInfo(ImmutableCallSite CS,
 
   if (Known == NoModRef)
     return NoModRef; // No need to query other mod/ref analyses
-  return ModRefResult(Known & AliasAnalysis::getModRefInfo(CS, P, Size));
+  return ModRefResult(Known & AliasAnalysis::getModRefInfo(CS, Loc));
 }
 
 
diff --git a/lib/Analysis/LibCallAliasAnalysis.cpp b/lib/Analysis/LibCallAliasAnalysis.cpp
index 7f51202ecb..62b9f463cb 100644
--- a/lib/Analysis/LibCallAliasAnalysis.cpp
+++ b/lib/Analysis/LibCallAliasAnalysis.cpp
@@ -43,8 +43,8 @@ void LibCallAliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
 /// vs the specified pointer/size.
 AliasAnalysis::ModRefResult
 LibCallAliasAnalysis::AnalyzeLibCallDetails(const LibCallFunctionInfo *FI,
-                                            ImmutableCallSite CS, const Value *P,
-                                            unsigned Size) {
+                                            ImmutableCallSite CS,
+                                            const Location &Loc) {
   // If we have a function, check to see what kind of mod/ref effects it
   // has.  Start by including any info globally known about the function.
   AliasAnalysis::ModRefResult MRInfo = FI->UniversalBehavior;
@@ -64,9 +64,9 @@ LibCallAliasAnalysis::AnalyzeLibCallDetails(const LibCallFunctionInfo *FI,
   if (FI->DetailsType == LibCallFunctionInfo::DoesNot) {
     // Find out if the pointer refers to a known location.
     for (unsigned i = 0; Details[i].LocationID != ~0U; ++i) {
-      const LibCallLocationInfo &Loc =
+      const LibCallLocationInfo &LocInfo =
       LCI->getLocationInfo(Details[i].LocationID);
-      LibCallLocationInfo::LocResult Res = Loc.isLocation(CS, P, Size);
+      LibCallLocationInfo::LocResult Res = LocInfo.isLocation(CS, Loc);
       if (Res != LibCallLocationInfo::Yes) continue;
       
       // If we find a match against a location that we 'do not' interact with,
@@ -85,9 +85,9 @@ LibCallAliasAnalysis::AnalyzeLibCallDetails(const LibCallFunctionInfo *FI,
   // Find out if the pointer refers to a known location.
   bool NoneMatch = true;
   for (unsigned i = 0; Details[i].LocationID != ~0U; ++i) {
-    const LibCallLocationInfo &Loc =
+    const LibCallLocationInfo &LocInfo =
     LCI->getLocationInfo(Details[i].LocationID);
-    LibCallLocationInfo::LocResult Res = Loc.isLocation(CS, P, Size);
+    LibCallLocationInfo::LocResult Res = LocInfo.isLocation(CS, Loc);
     if (Res == LibCallLocationInfo::No) continue;
     
     // If we don't know if this pointer points to the location, then we have to
@@ -118,7 +118,7 @@ LibCallAliasAnalysis::AnalyzeLibCallDetails(const LibCallFunctionInfo *FI,
 //
 AliasAnalysis::ModRefResult
 LibCallAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
-                                    const Value *P, unsigned Size) {
+                                    const Location &Loc) {
   ModRefResult MRInfo = ModRef;
   
   // If this is a direct call to a function that LCI knows about, get the
@@ -126,12 +126,12 @@ LibCallAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
   if (LCI) {
     if (const Function *F = CS.getCalledFunction()) {
       if (const LibCallFunctionInfo *FI = LCI->getFunctionInfo(F)) {
-        MRInfo = ModRefResult(MRInfo & AnalyzeLibCallDetails(FI, CS, P, Size));
+        MRInfo = ModRefResult(MRInfo & AnalyzeLibCallDetails(FI, CS, Loc));
         if (MRInfo == NoModRef) return NoModRef;
       }
     }
   }
   
   // The AliasAnalysis base class has some smarts, lets use them.
-  return (ModRefResult)(MRInfo | AliasAnalysis::getModRefInfo(CS, P, Size));
+  return (ModRefResult)(MRInfo | AliasAnalysis::getModRefInfo(CS, Loc));
 }
diff --git a/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp b/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp
index 93b2a8b06f..d7ecdde3e6 100644
--- a/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp
+++ b/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp
@@ -49,8 +49,7 @@ namespace {
   private:
     virtual void getAnalysisUsage(AnalysisUsage &AU) const;
     virtual bool runOnFunction(Function &F);
-    virtual AliasResult alias(const Value *V1, unsigned V1Size,
-                              const Value *V2, unsigned V2Size);
+    virtual AliasResult alias(const Location &LocA, const Location &LocB);
 
     Value *GetBaseValue(const SCEV *S);
   };
@@ -101,17 +100,17 @@ ScalarEvolutionAliasAnalysis::GetBaseValue(const SCEV *S) {
 }
 
 AliasAnalysis::AliasResult
-ScalarEvolutionAliasAnalysis::alias(const Value *A, unsigned ASize,
-                                    const Value *B, unsigned BSize) {
+ScalarEvolutionAliasAnalysis::alias(const Location &LocA,
+                                    const Location &LocB) {
   // If either of the memory references is empty, it doesn't matter what the
   // pointer values are. This allows the code below to ignore this special
   // case.
-  if (ASize == 0 || BSize == 0)
+  if (LocA.Size == 0 || LocB.Size == 0)
     return NoAlias;
 
   // This is ScalarEvolutionAliasAnalysis. Get the SCEVs!
-  const SCEV *AS = SE->getSCEV(const_cast<Value *>(A));
-  const SCEV *BS = SE->getSCEV(const_cast<Value *>(B));
+  const SCEV *AS = SE->getSCEV(const_cast<Value *>(LocA.Ptr));
+  const SCEV *BS = SE->getSCEV(const_cast<Value *>(LocB.Ptr));
 
   // If they evaluate to the same expression, it's a MustAlias.
   if (AS == BS) return MustAlias;
@@ -121,8 +120,8 @@ ScalarEvolutionAliasAnalysis::alias(const Value *A, unsigned ASize,
   if (SE->getEffectiveSCEVType(AS->getType()) ==
       SE->getEffectiveSCEVType(BS->getType())) {
     unsigned BitWidth = SE->getTypeSizeInBits(AS->getType());
-    APInt ASizeInt(BitWidth, ASize);
-    APInt BSizeInt(BitWidth, BSize);
+    APInt ASizeInt(BitWidth, LocA.Size);
+    APInt BSizeInt(BitWidth, LocB.Size);
 
     // Compute the difference between the two pointers.
     const SCEV *BA = SE->getMinusSCEV(BS, AS);
@@ -154,11 +153,15 @@ ScalarEvolutionAliasAnalysis::alias(const Value *A, unsigned ASize,
   // inttoptr and ptrtoint operators.
   Value *AO = GetBaseValue(AS);
   Value *BO = GetBaseValue(BS);
-  if ((AO && AO != A) || (BO && BO != B))
-    if (alias(AO ? AO : A, AO ? UnknownSize : ASize,
-              BO ? BO : B, BO ? UnknownSize : BSize) == NoAlias)
+  if ((AO && AO != LocA.Ptr) || (BO && BO != LocB.Ptr))
+    if (alias(Location(AO ? AO : LocA.Ptr,
+                       AO ? +UnknownSize : LocA.Size,
+                       AO ? 0 : LocA.TBAATag),
+              Location(BO ? BO : LocB.Ptr,
+                       BO ? +UnknownSize : LocB.Size,
+                       BO ? 0 : LocB.TBAATag)) == NoAlias)
       return NoAlias;
 
   // Forward the query to the next analysis.
-  return AliasAnalysis::alias(A, ASize, B, BSize);
+  return AliasAnalysis::alias(LocA, LocB);
 }
diff --git a/lib/Analysis/TypeBasedAliasAnalysis.cpp b/lib/Analysis/TypeBasedAliasAnalysis.cpp
index bbfdcec3f9..f6c8201c03 100644
--- a/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -96,9 +96,8 @@ namespace {
 
   private:
     virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-    virtual AliasResult alias(const Value *V1, unsigned V1Size,
-                              const Value *V2, unsigned V2Size);
-    virtual bool pointsToConstantMemory(const Value *P);
+    virtual AliasResult alias(const Location &LocA, const Location &LocB);
+    virtual bool pointsToConstantMemory(const Location &Loc);
   };
 }  // End of anonymous namespace
 
@@ -118,12 +117,12 @@ TypeBasedAliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
 }
 
 AliasAnalysis::AliasResult
-TypeBasedAliasAnalysis::alias(const Value *A, unsigned ASize,
-                              const Value *B, unsigned BSize) {
+TypeBasedAliasAnalysis::alias(const Location &LocA,
+                              const Location &LocB) {
   // Currently, metadata can only be attached to Instructions.
-  const Instruction *AI = dyn_cast<Instruction>(A);
+  const Instruction *AI = dyn_cast<Instruction>(LocA.Ptr);
   if (!AI) return MayAlias;
-  const Instruction *BI = dyn_cast<Instruction>(B);
+  const Instruction *BI = dyn_cast<Instruction>(LocB.Ptr);
   if (!BI) return MayAlias;
 
   // Get the attached MDNodes. If either value lacks a tbaa MDNode, we must
@@ -175,9 +174,9 @@ TypeBasedAliasAnalysis::alias(const Value *A, unsigned ASize,
   return MayAlias;
 }
 
-bool TypeBasedAliasAnalysis::pointsToConstantMemory(const Value *P) {
+bool TypeBasedAliasAnalysis::pointsToConstantMemory(const Location &Loc) {
   // Currently, metadata can only be attached to Instructions.
-  const Instruction *I = dyn_cast<Instruction>(P);
+  const Instruction *I = dyn_cast<Instruction>(Loc.Ptr);
   if (!I) return false;
 
   MDNode *M =
diff --git a/lib/VMCore/LLVMContext.cpp b/lib/VMCore/LLVMContext.cpp
index 60fb830e9b..15ae0ec5d5 100644
--- a/lib/VMCore/LLVMContext.cpp
+++ b/lib/VMCore/LLVMContext.cpp
@@ -28,9 +28,16 @@ LLVMContext& llvm::getGlobalContext() {
 }
 
 LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) {
-  // Create the first metadata kind, which is always 'dbg'.
+  // Create the fixed metadata kinds. This is done in the same order as the
+  // MD_* enum values so that they correspond.
+
+  // Create the 'dbg' metadata kind. 
   unsigned DbgID = getMDKindID("dbg");
   assert(DbgID == MD_dbg && "dbg kind id drifted"); (void)DbgID;
+
+  // Create the 'tbaa' metadata kind.
+  unsigned TBAAID = getMDKindID("tbaa");
+  assert(TBAAID == MD_tbaa && "tbaa kind id drifted"); (void)TBAAID;
 }
 LLVMContext::~LLVMContext() { delete pImpl; }