Don't add a null successor to a CFGBlock when the contents of an @synchronized statement is empty.

Fixes <rdar://problem/7979430>.

llvm-svn: 103717

2 files changed, 11 insertions, 2 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index 7f71e0acf7a..c7eb53d3613 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -1223,10 +1223,9 @@ CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) {
       return 0;
 
     Block = 0;
+    Succ = SyncBlock;
   }
 
-  Succ = SyncBlock;
-
   // Inline the sync expression.
   return addStmt(S->getSynchExpr());
 }
diff --git a/clang/test/Analysis/misc-ps.m b/clang/test/Analysis/misc-ps.m
index 2b21eec18cd..7061f6b2d10 100644
--- a/clang/test/Analysis/misc-ps.m
+++ b/clang/test/Analysis/misc-ps.m
@@ -957,3 +957,13 @@ void pr6938_b() {
   }) == 0) {
   }
 }
+
+//===----------------------------------------------------------------------===//
+// <rdar://problem/7979430> - The CFG for code containing an empty
+//  @synchronized block was previously broken (and would crash the analyzer).
+//===----------------------------------------------------------------------===//
+
+void r7979430(id x) {
+  @synchronized(x) {}
+}
+