Instead of recovering from a wrong invalidation, this patch aims to

invalidate the region correctly. It uses the cast-to type to invalidate 
the region when available. To avoid invalid cast-to type like 'void*' or 'id',
region store now only records non-generic casts of regions.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75580 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 32 insertions, 0 deletions

diff --git a/lib/Analysis/RegionStore.cpp b/lib/Analysis/RegionStore.cpp
index c59d935c3d..577ace306b 100644
--- a/lib/Analysis/RegionStore.cpp
+++ b/lib/Analysis/RegionStore.cpp
@@ -327,6 +327,10 @@ public:
   const GRState *setCastType(const GRState *state, const MemRegion* R,
                              QualType T);
 
+  const QualType *getCastType(const GRState *state, const MemRegion *R) {
+    return state->get<RegionCasts>(R);
+  }
+
   static inline RegionBindingsTy GetRegionBindings(Store store) {
    return RegionBindingsTy(static_cast<const RegionBindingsTy::TreeTy*>(store));
   }
@@ -349,6 +353,27 @@ public:
 
 } // end anonymous namespace
 
+static bool isGenericPtr(ASTContext &Ctx, QualType Ty) {
+  if (Ty->isObjCIdType() || Ty->isObjCQualifiedIdType())
+    return true;
+
+  while (true) {
+    Ty = Ctx.getCanonicalType(Ty);
+    
+    if (Ty->isVoidType())
+      return true;
+    
+    if (const PointerType *PT = Ty->getAsPointerType()) {
+      Ty = PT->getPointeeType();
+      continue;
+    }
+    
+    break;
+  }
+  
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // RegionStore creation.
 //===----------------------------------------------------------------------===//
@@ -1251,6 +1276,13 @@ const GRState *RegionStoreManager::RemoveRegionView(const GRState *state,
 
 const GRState *RegionStoreManager::setCastType(const GRState *state, 
 					       const MemRegion* R, QualType T) {
+  // We do not record generic cast type, since we are using cast type to
+  // invlidate regions, and generic type is meaningless for invalidating
+  // regions.
+  // If the region already has a cast type before, that type is preserved.
+  // FIXME: is this the right thing to do?
+  if (isGenericPtr(getContext(), T))
+    return state;
   return state->set<RegionCasts>(R, T);
 }