[analyzer] Handle the dot syntax for properties in the ExprEngine.

We translate property accesses to obj-c messages by simulating "loads" or "stores" to properties
using a pseudo-location SVal kind (ObjCPropRef).

Checkers can now reason about obj-c messages for both explicit message expressions and implicit
messages due to property accesses.

llvm-svn: 124161
diff --git a/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
index e6a40bb..1f5f233 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
@@ -246,10 +246,11 @@
       return;
     }
 
+  const char *bugDesc = msg.isPropertySetter() ?
+                     "Argument for property setter is an uninitialized value"
+                   : "Argument in message expression is an uninitialized value";
   // Check for any arguments that are uninitialized/undefined.
-  PreVisitProcessArgs(C, CallOrObjCMessage(msg, state),
-                      "Argument in message expression "
-                      "is an uninitialized value", BT_msg_arg);
+  PreVisitProcessArgs(C, CallOrObjCMessage(msg, state), bugDesc, BT_msg_arg);
 }
 
 bool CallAndMessageChecker::evalNilReceiver(CheckerContext &C,