Polish diagnostics for null dereferences via ObjC ivar accesses. Finishes up...

Polish diagnostics for null dereferences via ObjC ivar accesses.  Finishes up <rdar://problem/6352035>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113612 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Checker/DereferenceChecker.cpp

@@ -123,6 +123,19 @@ void DereferenceChecker::VisitLocation(CheckerContext &C, const Stmt *S,
             }
           break;
         }
+        case Stmt::ObjCIvarRefExprClass: {
+          const ObjCIvarRefExpr *IV = cast<ObjCIvarRefExpr>(S);
+          if (const DeclRefExpr *DR =
+              dyn_cast<DeclRefExpr>(IV->getBase()->IgnoreParenCasts())) {
+            if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
+              llvm::raw_svector_ostream os(buf);
+              os << "Instance variable access (via '" << VD->getName()
+                 << "') results in a null pointer dereference";
+            }
+          }
+          Ranges.push_back(IV->getSourceRange());
+          break;
+        }
         default:
           break;
       }

test/Analysis/misc-ps.m

@@ -1110,3 +1110,22 @@ void rdar6351970_c() {
   @synchronized(x) {} // expected-warning{{Uninitialized value used as mutex for @synchronized}}
 }
 
+// <rdar://problem/6352035> rule request: direct structure member access null pointer dereference
+@interface RDar6352035 {
+  int c;
+}
+- (void)foo;
+- (void)bar;
+@end
+
+@implementation RDar6352035
+- (void)foo {
+  RDar6352035 *friend = 0;
+  friend->c = 7; // expected-warning{{Instance variable access (via 'friend') results in a null pointer dereference}}
+}
+- (void)bar {
+  self = 0;
+  c = 7; // expected-warning{{Instance variable access (via 'self') results in a null pointer dereference}}
+}
+@end
+