Clean up the Checker API a little more, resolving some hidden bugs
along the way.  Important changes:

1) To generate a sink node, use GenerateSink(); GenerateNode() is for
generating regular transitions.  This makes the API clearer and also
allows us to use the 'bool' option to GenerateNode() for a different
purpose.

2) GenerateNode() now automatically adds the generated node to the
destination ExplodedNodeSet (autotransition) unless the client
specifies otherwise with a bool flag.  Several checkers did not call
'addTransition()' after calling 'GenerateNode()', causing the
simulation path to be prematurely culled when a non-fail stop bug was
encountered.

3) Add variants of GenerateNode()/GenerateSink() that take neither a
Stmt* or a GRState*; most callers of GenerateNode() just pass in the
same Stmt* as provided when the CheckerContext object is created; we
can just use that the majority of the time.  This cleanup also allows
us to potentially coelesce the APIs for evaluating branches and
end-of-paths (which currently directly use builders).

4) addTransition() no longer needs to be called except for a few
cases.  We now have a variant of addTransition() that takes a
GRState*; this allows one to propagate the updated state without
caring about generating a new node explicitly.  This nicely cleaned up
a bunch of cases that called autoTransition() with a bunch of
conditional logic surround the call (that common logic has now been
swallowed up by addTransition() itself).

llvm-svn: 89707
diff --git a/clang/lib/Analysis/VLASizeChecker.cpp b/clang/lib/Analysis/VLASizeChecker.cpp
index 799a73e..9a3436c 100644
--- a/clang/lib/Analysis/VLASizeChecker.cpp
+++ b/clang/lib/Analysis/VLASizeChecker.cpp
@@ -55,7 +55,7 @@
 
   if (sizeV.isUndef()) {
     // Generate an error node.
-    ExplodedNode *N = C.GenerateNode(DS, true);    
+    ExplodedNode *N = C.GenerateSink();
     if (!N)
       return;
     
@@ -78,7 +78,7 @@
   llvm::tie(stateNotZero, stateZero) = state->Assume(sizeD);
 
   if (stateZero && !stateNotZero) {
-    ExplodedNode* N = C.GenerateNode(DS, stateZero, true);
+    ExplodedNode* N = C.GenerateSink(stateZero);
     if (!BT_zero)
       BT_zero = new BuiltinBug("Declared variable-length array (VLA) has zero "
                                "size");
@@ -92,6 +92,5 @@
   }
  
   // From this point on, assume that the size is not zero.
-  if (state != stateNotZero)
-    C.addTransition(C.GenerateNode(DS, stateNotZero));  
+  C.addTransition(stateNotZero);
 }