Added some comments to GRExprEngine.  Reorder some of the method definitions
to start logically organizing them.

Added initial plug-in transfer function support for Objective-C message expressions.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@49752 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/GRSimpleVals.cpp b/lib/Analysis/GRSimpleVals.cpp
index dabae43..c8805ab 100644
--- a/lib/Analysis/GRSimpleVals.cpp
+++ b/lib/Analysis/GRSimpleVals.cpp
@@ -552,7 +552,7 @@
 }
 
 //===----------------------------------------------------------------------===//
-// Transfer function for Function Calls.
+// Transfer function for function calls.
 //===----------------------------------------------------------------------===//
 
 void GRSimpleVals::EvalCall(ExplodedNodeSet<ValueState>& Dst,
@@ -590,3 +590,32 @@
     
   Builder.MakeNode(Dst, CE, Pred, St);
 }
+
+//===----------------------------------------------------------------------===//
+// Transfer function for Objective-C message expressions.
+//===----------------------------------------------------------------------===//
+
+void GRSimpleVals::EvalObjCMessageExpr(ExplodedNodeSet<ValueState>& Dst,
+                                       GRExprEngine& Eng,
+                                       GRStmtNodeBuilder<ValueState>& Builder,
+                                       ObjCMessageExpr* ME,
+                                       ExplodedNode<ValueState>* Pred) {
+  
+  
+  // The basic transfer function logic for message expressions does nothing.
+  // We just invalidate all arguments passed in by references.
+  
+  ValueStateManager& StateMgr = Eng.getStateManager();
+  ValueState* St = Builder.GetState(Pred);
+  
+  for (ObjCMessageExpr::arg_iterator I = ME->arg_begin(), E = ME->arg_end();
+       I != E; ++I) {
+    
+    RVal V = StateMgr.GetRVal(St, *I);
+    
+    if (isa<LVal>(V))
+      St = StateMgr.SetRVal(St, cast<LVal>(V), UnknownVal());
+  }
+  
+  Builder.MakeNode(Dst, ME, Pred, St);
+}