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).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89707 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/AttrNonNullChecker.cpp b/lib/Analysis/AttrNonNullChecker.cpp
index 01e1a1f..8668c75 100644
--- a/lib/Analysis/AttrNonNullChecker.cpp
+++ b/lib/Analysis/AttrNonNullChecker.cpp
@@ -39,7 +39,6 @@
 void AttrNonNullChecker::PreVisitCallExpr(CheckerContext &C, 
                                           const CallExpr *CE) {
   const GRState *state = C.getState();
-  const GRState *originalState = state;
 
   // Check if the callee has a 'nonnull' attribute.
   SVal X = state->getSVal(CE->getCallee());
@@ -74,7 +73,7 @@
     if (stateNull && !stateNotNull) {
       // Generate an error node.  Check for a null node in case
       // we cache out.
-      if (ExplodedNode *errorNode = C.GenerateNode(CE, stateNull, true)) {
+      if (ExplodedNode *errorNode = C.GenerateSink(stateNull)) {
 
         // Lazily allocate the BugType object if it hasn't already been
         // created. Ownership is transferred to the BugReporter object once
@@ -109,6 +108,5 @@
 
   // If we reach here all of the arguments passed the nonnull check.
   // If 'state' has been updated generated a new node.
-  if (state != originalState)
-    C.addTransition(C.GenerateNode(CE, state));
+  C.addTransition(state);
 }