[llvm-commits] [llvm] r77623 - in /llvm/trunk: include/llvm/Analysis/AliasSetTracker.h lib/Analysis/AliasSetTracker.cpp

[Dan Gohman]

Author: djg
Date: Thu Jul 30 15:21:41 2009
New Revision: 77623

URL: http://llvm.org/viewvc/llvm-project?rev=77623&view=rev
Log:
Use CallbackVH in AliasSetTracker to avoid getting stuck with
dangling Value*s.

Modified:
    llvm/trunk/include/llvm/Analysis/AliasSetTracker.h
    llvm/trunk/lib/Analysis/AliasSetTracker.cpp

Modified: llvm/trunk/include/llvm/Analysis/AliasSetTracker.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/AliasSetTracker.h?rev=77623&r1=77622&r2=77623&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Analysis/AliasSetTracker.h (original)
+++ llvm/trunk/include/llvm/Analysis/AliasSetTracker.h Thu Jul 30 15:21:41 2009
@@ -18,6 +18,7 @@
 #define LLVM_ANALYSIS_ALIASSETTRACKER_H
 
 #include "llvm/Support/CallSite.h"
+#include "llvm/Support/ValueHandle.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/ilist.h"
@@ -251,11 +252,24 @@
 
 
 class AliasSetTracker {
+  /// CallbackVH - A CallbackVH to arrange for AliasSetTracker to be
+  /// notified whenever a Value is deleted.
+  class ASTCallbackVH : public CallbackVH {
+    AliasSetTracker *AST;
+    virtual void deleted();
+  public:
+    ASTCallbackVH(Value *V, AliasSetTracker *AST = 0);
+  };
+
   AliasAnalysis &AA;
   ilist<AliasSet> AliasSets;
 
+  typedef DenseMap<ASTCallbackVH, AliasSet::PointerRec*, DenseMapInfo<Value*> >
+    PointerMapType;
+
   // Map from pointers to their node
-  DenseMap<Value*, AliasSet::PointerRec*> PointerMap;
+  PointerMapType PointerMap;
+
 public:
   /// AliasSetTracker ctor - Create an empty collection of AliasSets, and use
   /// the specified alias analysis object to disambiguate load and store
@@ -364,7 +378,7 @@
   // getEntryFor - Just like operator[] on the map, except that it creates an
   // entry for the pointer if it doesn't already exist.
   AliasSet::PointerRec &getEntryFor(Value *V) {
-    AliasSet::PointerRec *&Entry = PointerMap[V];
+    AliasSet::PointerRec *&Entry = PointerMap[ASTCallbackVH(V, this)];
     if (Entry == 0)
       Entry = new AliasSet::PointerRec(V);
     return *Entry;

Modified: llvm/trunk/lib/Analysis/AliasSetTracker.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasSetTracker.cpp?rev=77623&r1=77622&r2=77623&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/AliasSetTracker.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasSetTracker.cpp Thu Jul 30 15:21:41 2009
@@ -187,8 +187,8 @@
 
 void AliasSetTracker::clear() {
   // Delete all the PointerRec entries.
-  for (DenseMap<Value*, AliasSet::PointerRec*>::iterator I = PointerMap.begin(),
-       E = PointerMap.end(); I != E; ++I)
+  for (PointerMapType::iterator I = PointerMap.begin(), E = PointerMap.end();
+       I != E; ++I)
     I->second->eraseFromList();
   
   PointerMap.clear();
@@ -485,7 +485,7 @@
         AS->removeCallSite(CS);
 
   // First, look up the PointerRec for this pointer.
-  DenseMap<Value*, AliasSet::PointerRec*>::iterator I = PointerMap.find(PtrVal);
+  PointerMapType::iterator I = PointerMap.find(PtrVal);
   if (I == PointerMap.end()) return;  // Noop
 
   // If we found one, remove the pointer from the alias set it is in.
@@ -511,7 +511,7 @@
   AA.copyValue(From, To);
 
   // First, look up the PointerRec for this pointer.
-  DenseMap<Value*, AliasSet::PointerRec*>::iterator I = PointerMap.find(From);
+  PointerMapType::iterator I = PointerMap.find(From);
   if (I == PointerMap.end())
     return;  // Noop
   assert(I->second->hasAliasSet() && "Dead entry?");
@@ -576,6 +576,22 @@
 void AliasSetTracker::dump() const { print(cerr); }
 
 //===----------------------------------------------------------------------===//
+//                     ASTCallbackVH Class Implementation
+//===----------------------------------------------------------------------===//
+
+void AliasSetTracker::ASTCallbackVH::deleted() {
+  assert(AST && "ASTCallbackVH called with a null AliasSetTracker!");
+  AST->deleteValue(getValPtr());
+  // this now dangles!
+}
+
+AliasSetTracker::ASTCallbackVH::ASTCallbackVH(Value *V, AliasSetTracker *ast)
+  : CallbackVH(V == DenseMapInfo<Value *>::getEmptyKey() ? 0 :
+               V == DenseMapInfo<Value *>::getTombstoneKey() ? 0 :
+               V),
+    AST(ast) {}
+
+//===----------------------------------------------------------------------===//
 //                            AliasSetPrinter Pass
 //===----------------------------------------------------------------------===//