Add a new symbol type, SymbolExtent, to represent the extents of memory regions that may not be known at compile-time (such as those created by malloc). This replaces the old setExtent/getExtent API on Store, which used the GRState's GDM to store SVals.

Also adds a getKnownValue() method to SValuator, which gets the integer value of an SVal if it is known to only have one possible value. There are more places in the code that could be using this, but in general we want to be dealing entirely in SVals, so its usefulness is limited.

The only visible functionality change is that extents are now honored for any DeclRegion, such as fields and Objective-C ivars, rather than just variables. This shows up in bounds-checking and cast-size-checking.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107577 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/Checker/SimpleSValuator.cpp b/lib/Checker/SimpleSValuator.cpp
index 5b24992118..3bc4ee7d06 100644
--- a/lib/Checker/SimpleSValuator.cpp
+++ b/lib/Checker/SimpleSValuator.cpp
@@ -34,6 +34,10 @@ public:
                            Loc lhs, Loc rhs, QualType resultTy);
   virtual SVal EvalBinOpLN(const GRState *state, BinaryOperator::Opcode op,
                            Loc lhs, NonLoc rhs, QualType resultTy);
+
+  /// getKnownValue - Evaluates a given SVal. If the SVal has only one possible
+  ///  (integer) value, that value is returned. Otherwise, returns NULL.
+  virtual const llvm::APSInt *getKnownValue(const GRState *state, SVal V);
   
   SVal MakeSymIntVal(const SymExpr *LHS, BinaryOperator::Opcode op,
                      const llvm::APSInt &RHS, QualType resultTy);
@@ -819,3 +823,21 @@ SVal SimpleSValuator::EvalBinOpLN(const GRState *state,
   return state->getStateManager().getStoreManager().EvalBinOp(op, lhs,
                                                               rhs, resultTy);
 }
+
+const llvm::APSInt *SimpleSValuator::getKnownValue(const GRState *state,
+                                                   SVal V) {
+  if (V.isUnknownOrUndef())
+    return NULL;
+
+  if (loc::ConcreteInt* X = dyn_cast<loc::ConcreteInt>(&V))
+    return &X->getValue();
+
+  if (nonloc::ConcreteInt* X = dyn_cast<nonloc::ConcreteInt>(&V))
+    return &X->getValue();
+
+  if (SymbolRef Sym = V.getAsSymbol())
+    return state->getSymVal(Sym);
+
+  // FIXME: Add support for SymExprs.
+  return NULL;
+}