[analyzer] Allow ObjC ivar lvalues where the base is nil.

By analogy with C structs, this seems to be legal, if probably discouraged.
It's only if the ivar is read from or written to that there's a problem.
Running a program that gets the "address" of an instance variable does in
fact return the offset when the base "object" is nil.

This isn't a full revert because r164442 includes some diagnostic tweaks
as well; those have been kept.

This partially reverts r164442 / 08965091770c9b276c238bac2f716eaa4da2dca4.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164960 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 12 deletions

diff --git a/lib/StaticAnalyzer/Core/ExprEngineObjC.cpp b/lib/StaticAnalyzer/Core/ExprEngineObjC.cpp
index ee315a4604..51dda19b53 100644
--- a/lib/StaticAnalyzer/Core/ExprEngineObjC.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineObjC.cpp
@@ -25,21 +25,11 @@ void ExprEngine::VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *Ex,
   ProgramStateRef state = Pred->getState();
   const LocationContext *LCtx = Pred->getLocationContext();
   SVal baseVal = state->getSVal(Ex->getBase(), LCtx);
-
-  // First check that the base object is valid.
-  ExplodedNodeSet DstLoc;
-  evalLocation(DstLoc, Ex, Ex, Pred, state, baseVal,
-               /*Tag=*/0, /*isLoad=*/true);
-
-  // Bind the lvalue to the expression.
   SVal location = state->getLValue(Ex->getDecl(), baseVal);
   
   ExplodedNodeSet dstIvar;
-  StmtNodeBuilder Bldr(DstLoc, dstIvar, *currBldrCtx);
-  for (ExplodedNodeSet::iterator I = DstLoc.begin(), E = DstLoc.end();
-       I != E; ++I) {
-    Bldr.generateNode(Ex, (*I), (*I)->getState()->BindExpr(Ex, LCtx, location));
-  }
+  StmtNodeBuilder Bldr(Pred, dstIvar, *currBldrCtx);
+  Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, location));
   
   // Perform the post-condition check of the ObjCIvarRefExpr and store
   // the created nodes in 'Dst'.