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.

llvm-svn: 113858

Author: Dan Gohman

Diff for: llvm/include/llvm/Analysis/AliasAnalysis.h

@@ -83,6 +83,22 @@ class AliasAnalysis {
   /// 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 @@ class AliasAnalysis {
   /// 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 @@ class AliasAnalysis {
 
 
   /// 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 
@@ -277,101 +339,31 @@ class AliasAnalysis {
   virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
                                      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 @@ class AliasAnalysis {
     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 for: llvm/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 for: llvm/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 for: llvm/include/llvm/LLVMContext.h

@@ -37,7 +37,8 @@ class LLVMContext {
   // 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.