Add 'MemRegion::getBaseRegion()', a utility method to strip ElementRegions with

index 0.  This will be used for refinements to InvalidateRegion and CastRegion.

llvm-svn: 77481

1 files changed, 20 insertions, 0 deletions

diff --git a/clang/lib/Analysis/MemRegion.cpp b/clang/lib/Analysis/MemRegion.cpp
index 9b8f7c81e1c..a708bd3068f 100644
--- a/clang/lib/Analysis/MemRegion.cpp
+++ b/clang/lib/Analysis/MemRegion.cpp
@@ -398,3 +398,23 @@ const MemRegion *TypedViewRegion::removeViews() const {
   }
   return R;
 }
+
+const MemRegion *MemRegion::getBaseRegion() const {
+  const MemRegion *R = this;
+  while (true) {
+    if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {      
+      // FIXME: generalize.  Essentially we want to strip away ElementRegions
+      // that were layered on a symbolic region because of casts.  We only
+      // want to strip away ElementRegions, however, where the index is 0.
+      SVal index = ER->getIndex();
+      if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&index)) {
+        if (CI->getValue().getZExtValue() == 0) {
+          R = ER->getSuperRegion();
+          continue;
+        }
+      }
+    }
+    break;
+  }
+  return R;
+}