Add a boilerplate for out-of-bound array checking. This has no real function currently.

llvm-svn: 58886

clang/include/clang/Analysis/PathSensitive/GRExprEngine.h

@@ -455,6 +455,15 @@ protected:
     return StateMgr.Assume(St, Cond, Assumption, isFeasible);
   }
 
+  const GRState* AssumeInBound(const GRState* St, SVal Idx, SVal UpperBound,
+                               bool Assumption, bool& isFeasible) {
+    // FIXME: In this function, we will check if Idx can be in/out 
+    // [0, UpperBound) according to the assumption.  We can extend the 
+    // interface to include a LowerBound parameter.
+    isFeasible = true;
+    return St;
+  }
+
   NodeTy* MakeNode(NodeSet& Dst, Stmt* S, NodeTy* Pred, const GRState* St,
                    ProgramPoint::Kind K = ProgramPoint::PostStmtKind) {
     assert (Builder && "GRStmtNodeBuilder not present.");

clang/include/clang/Analysis/PathSensitive/Store.h

@@ -72,7 +72,11 @@ public:
                               const FieldDecl* D) = 0;
   
   virtual SVal getLValueElement(const GRState* St, SVal Base, SVal Offset) = 0;
-  
+
+  virtual SVal getSizeInElements(const GRState* St, const MemRegion* R) {
+    return UnknownVal();
+  }
+
   /// ArrayToPointer - Used by GRExprEngine::VistCast to handle implicit
   ///  conversions between arrays and pointers.
   virtual SVal ArrayToPointer(SVal Array) = 0;

clang/lib/Analysis/GRExprEngine.cpp

@@ -1067,6 +1067,28 @@ const GRState* GRExprEngine::EvalLocation(Expr* Ex, NodeTy* Pred,
       else ExplicitNullDeref.insert(NullNode);
     }
   }
+
+  // Check for out-of-bound array access.
+  if (isFeasibleNotNull && isa<loc::MemRegionVal>(LV)) {
+    const MemRegion* R = cast<loc::MemRegionVal>(LV).getRegion();
+    if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
+      // Get the index of the accessed element.
+      SVal Idx = ER->getIndex();
+      // Get the extent of the array.
+      SVal NumElements = StateMgr.getStoreManager().getSizeInElements(StNotNull,
+                                                       ER->getSuperRegion());
+
+      bool isFeasibleInBound = false;
+      const GRState* StInBound = AssumeInBound(StNotNull, Idx, NumElements, 
+                                               true, isFeasibleInBound);
+
+      bool isFeasibleOutBound = false;
+      const GRState* StOutBound = AssumeInBound(StNotNull, Idx, NumElements, 
+                                                false, isFeasibleOutBound);
+
+      // Report warnings ...
+    }
+  }
   
   return isFeasibleNotNull ? StNotNull : NULL;
 }