[analyzer] Rename generateNode -> addTransition in CheckerContext

Also document addTransition methods.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143059 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp b/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
index a57d031..d00ef59 100644
--- a/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
@@ -49,7 +49,7 @@
     // For __builtin_expect, just return the value of the subexpression.
     assert (CE->arg_begin() != CE->arg_end());
     SVal X = state->getSVal(*(CE->arg_begin()));
-    C.generateNode(state->BindExpr(CE, X));
+    C.addTransition(state->BindExpr(CE, X));
     return true;
   }
 
@@ -72,7 +72,7 @@
       svalBuilder.evalEQ(state, Extent, Size);
     state = state->assume(extentMatchesSizeArg, true);
 
-    C.generateNode(state->BindExpr(CE, loc::MemRegionVal(R)));
+    C.addTransition(state->BindExpr(CE, loc::MemRegionVal(R)));
     return true;
   }
   }