Cleanups and fixes to the nil-receiver checker, some of it fallout the

initial transition of the nil-receiver checker to the Checker
interface as done in r89745.  Some important changes include:

1) We consolidate the BugType object used for nil receiver bug
reports, and don't include the type of the returned value in the
BugType (which would be wrong if a nil receiver bug was reported more
than once)

2) Added a new (temporary) flag to CheckerContext: DoneEvauating.
This is used by GRExprEngine when evaluating message expressions to
not continue evaluating the message expression if this flag is set.
This flag is currently set by the nil receiver checker.  This is an
intermediate solution to allow the nil-receiver checker to properly
work as a plug-in outside of GRExprEngine.  Basically, this flag
indicates that the entire message expression has been evaluated, not
just a precondition (which is what the nil-receiver checker does).
This flag *should not* be repurposed for general use, but just to pull
more things out of GRExprEngine that already in there as we devise a
better interface in the Checker class.

3) Cleaned up the logic in the nil-receiver checker, making the
control-flow a lot easier to read.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89804 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 27 insertions, 7 deletions

diff --git a/include/clang/Analysis/PathSensitive/Checker.h b/include/clang/Analysis/PathSensitive/Checker.h
index f6a5074fd8..91a4b6d1b1 100644
--- a/include/clang/Analysis/PathSensitive/Checker.h
+++ b/include/clang/Analysis/PathSensitive/Checker.h
@@ -42,6 +42,7 @@ class CheckerContext {
   const GRState *state;
   const Stmt *statement;
   const unsigned size;
+  bool DoneEvaluating; // FIXME: This is not a permanent API change.
 public:
   CheckerContext(ExplodedNodeSet &dst, GRStmtNodeBuilder &builder,
                  GRExprEngine &eng, ExplodedNode *pred,
@@ -52,10 +53,22 @@ public:
       OldTag(B.Tag, tag),
       OldPointKind(B.PointKind, K),
       OldHasGen(B.HasGeneratedNode),
-      state(st), statement(stmt), size(Dst.size()) {}
+      state(st), statement(stmt), size(Dst.size()),
+      DoneEvaluating(false) {}
 
   ~CheckerContext();
   
+  // FIXME: This were added to support CallAndMessageChecker to indicating
+  // to GRExprEngine to "stop evaluating" a message expression under certain
+  // cases.  This is *not* meant to be a permanent API change, and was added
+  // to aid in the transition of removing logic for checks from GRExprEngine.  
+  void setDoneEvaluating() {
+    DoneEvaluating = true;
+  }
+  bool isDoneEvaluating() const {
+    return DoneEvaluating;
+  }
+  
   ConstraintManager &getConstraintManager() {
       return Eng.getConstraintManager();
   }
@@ -152,7 +165,7 @@ private:
   friend class GRExprEngine;
 
   // FIXME: Remove the 'tag' option.
-  void GR_Visit(ExplodedNodeSet &Dst,
+  bool GR_Visit(ExplodedNodeSet &Dst,
                 GRStmtNodeBuilder &Builder,
                 GRExprEngine &Eng,
                 const Stmt *S,
@@ -164,6 +177,7 @@ private:
       _PreVisit(C, S);
     else
       _PostVisit(C, S);
+    return C.isDoneEvaluating();
   }
 
   // FIXME: Remove the 'tag' option.
diff --git a/include/clang/Analysis/PathSensitive/ExplodedGraph.h b/include/clang/Analysis/PathSensitive/ExplodedGraph.h
index a7bbdf939f..76cab1ddc1 100644
--- a/include/clang/Analysis/PathSensitive/ExplodedGraph.h
+++ b/include/clang/Analysis/PathSensitive/ExplodedGraph.h
@@ -352,10 +352,16 @@ public:
   typedef ImplTy::iterator       iterator;
   typedef ImplTy::const_iterator const_iterator;
 
-  inline unsigned size() const { return Impl.size();  }
-  inline bool empty()    const { return Impl.empty(); }
-
-  inline void clear() { Impl.clear(); }
+  unsigned size() const { return Impl.size();  }
+  bool empty()    const { return Impl.empty(); }
+
+  void clear() { Impl.clear(); }
+  void insert(const ExplodedNodeSet &S) {
+    if (empty())
+      Impl = S.Impl;
+    else
+      Impl.insert(S.begin(), S.end());
+  }
 
   inline iterator begin() { return Impl.begin(); }
   inline iterator end()   { return Impl.end();   }
diff --git a/include/clang/Analysis/PathSensitive/GRExprEngine.h b/include/clang/Analysis/PathSensitive/GRExprEngine.h
index 1512b9099f..99ff57443b 100644
--- a/include/clang/Analysis/PathSensitive/GRExprEngine.h
+++ b/include/clang/Analysis/PathSensitive/GRExprEngine.h
@@ -222,7 +222,7 @@ public:
 protected:
   /// CheckerVisit - Dispatcher for performing checker-specific logic
   ///  at specific statements.
-  void CheckerVisit(Stmt *S, ExplodedNodeSet &Dst, ExplodedNodeSet &Src, 
+  bool CheckerVisit(Stmt *S, ExplodedNodeSet &Dst, ExplodedNodeSet &Src, 
                     bool isPrevisit);
   
   void CheckerVisitBind(const Stmt *AssignE, const Stmt *StoreE,