Teach MemRegion::getBaseRegion() about ObjCIvarRegions. We want to treat

them the same way as fields.  This fixes a regression in RegionStore::RemoveDeadbindings()
that emerged from going to the cluster-based analysis.

llvm-svn: 100570

2 files changed, 29 insertions, 7 deletions

diff --git a/clang/lib/Checker/MemRegion.cpp b/clang/lib/Checker/MemRegion.cpp
index 9f12ab622fb..0571d81f902 100644
--- a/clang/lib/Checker/MemRegion.cpp
+++ b/clang/lib/Checker/MemRegion.cpp
@@ -647,13 +647,14 @@ bool MemRegion::hasGlobalsOrParametersStorage() const {
 const MemRegion *MemRegion::getBaseRegion() const {
   const MemRegion *R = this;
   while (true) {
-    if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
-      R = ER->getSuperRegion();
-      continue;
-    }
-    if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
-      R = FR->getSuperRegion();
-      continue;
+    switch (R->getKind()) {
+      case MemRegion::ElementRegionKind:
+      case MemRegion::FieldRegionKind:
+      case MemRegion::ObjCIvarRegionKind:
+        R = cast<SubRegion>(R)->getSuperRegion();
+        continue;
+      default:
+        break;
     }
     break;
   }
diff --git a/clang/test/Analysis/misc-ps-region-store.m b/clang/test/Analysis/misc-ps-region-store.m
index d10b9fa5ded..0e305bf1dfb 100644
--- a/clang/test/Analysis/misc-ps-region-store.m
+++ b/clang/test/Analysis/misc-ps-region-store.m
@@ -955,3 +955,24 @@ void pr6288_b(void) {
   *(px[0]) = 0; // no-warning
 }
 
+// <rdar://problem/7817800> - A bug in RemoveDeadBindings was causing instance variable bindings
+//  to get prematurely pruned from the state.
+@interface Rdar7817800 {
+  char *x;
+}
+- (void) rdar7817800_baz;
+@end
+
+char *rdar7817800_foobar();
+void rdar7817800_qux(void*);
+
+@implementation Rdar7817800
+- (void) rdar7817800_baz {
+  if (x)
+    rdar7817800_qux(x);
+  x = rdar7817800_foobar();
+  // Previously this triggered a bogus null dereference warning.
+  x[1] = 'a'; // no-warning
+}
+@end
+