Because I like being able to instantiate the cfgprinter from external projects,

[oota-llvm.git] / include / llvm / Analysis / AliasAnalysis.h

diff --git a/include/llvm/Analysis/AliasAnalysis.h b/include/llvm/Analysis/AliasAnalysis.h
index 5be8af899c00cf87f029dd7e61b553d108927c32..54ea494869930538cbe2b6c7cefe2255e7648918 100644 (file)
--- a/include/llvm/Analysis/AliasAnalysis.h
+++ b/include/llvm/Analysis/AliasAnalysis.h
@@ -101,7 +101,9 @@ public:
   virtual bool pointsToConstantMemory(const Value *P) { return false; }
 
   /// doesNotAccessMemory - If the specified function is known to never read or
-  /// write memory, return true.
+  /// write memory, return true.  If the function only reads from known-constant
+  /// memory, it is also legal to return true.  Functions that unwind the stack
+  /// are not legal for this predicate.
   ///
   /// Many optimizations (such as CSE and LICM) can be performed on calls to it,
   /// without worrying about aliasing properties, and many functions have this
@@ -112,7 +114,8 @@ public:
   virtual bool doesNotAccessMemory(Function *F) { return false; }
 
   /// onlyReadsMemory - If the specified function is known to only read from
-  /// non-volatile memory (or not access memory at all), return true.
+  /// non-volatile memory (or not access memory at all), return true.  Functions
+  /// that unwind the stack are not legal for this predicate.
   ///
   /// This property allows many common optimizations to be performed in the
   /// absence of interfering store instructions, such as CSE of strlen calls.
@@ -139,29 +142,32 @@ public:
   /// a particular call site modifies or reads the memory specified by the
   /// pointer.
   ///
-  virtual ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size) {
-    // If P points to a constant memory location, the call definitely could not
-    // modify the memory location.
-    return pointsToConstantMemory(P) ? Ref : ModRef;
-  }
+  virtual ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
 
   /// getModRefInfo - Return information about whether two call sites may refer
   /// to the same set of memory locations.  This function returns NoModRef if
-  /// the two calls refer to disjoint memory locations, Ref if they both read
-  /// some of the same memory, Mod if they both write to some of the same
-  /// memory, and ModRef if they read and write to the same memory.
+  /// the two calls refer to disjoint memory locations, Ref if CS1 reads memory
+  /// written by CS2, Mod if CS1 writes to memory read or written by CS2, or
+  /// ModRef if CS1 might read or write memory accessed by CS2.
   ///
-  virtual ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
-    return ModRef;
-  }
+  virtual ModRefResult getModRefInfo(CallSite CS1, CallSite CS2);
+
+  /// hasNoModRefInfoForCalls - Return true if the analysis has no mod/ref
+  /// information for pairs of function calls (other than "pure" and "const"
+  /// functions).  This can be used by clients to avoid many pointless queries.
+  /// Remember that if you override this and chain to another analysis, you must
+  /// make sure that it doesn't have mod/ref info either.
+  ///
+  virtual bool hasNoModRefInfoForCalls() const { return false; }
+
 
   /// Convenience functions...
   ModRefResult getModRefInfo(LoadInst *L, Value *P, unsigned Size);
-  ModRefResult getModRefInfo(StoreInst*S, Value *P, unsigned Size);
-  ModRefResult getModRefInfo(CallInst  *C, Value *P, unsigned Size) {
+  ModRefResult getModRefInfo(StoreInst *S, Value *P, unsigned Size);
+  ModRefResult getModRefInfo(CallInst *C, Value *P, unsigned Size) {
     return getModRefInfo(CallSite(C), P, Size);
   }
-  ModRefResult getModRefInfo(InvokeInst*I, Value *P, unsigned Size) {
+  ModRefResult getModRefInfo(InvokeInst *I, Value *P, unsigned Size) {
     return getModRefInfo(CallSite(I), P, Size);
   }
   ModRefResult getModRefInfo(Instruction *I, Value *P, unsigned Size) {