Unify the implementation of getLValueElement of store managers.
It's more sophisticated than the original one of BasicStore. But it does
matter.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95536 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/Store.cpp b/lib/Checker/Store.cpp
index 7190bda..d68369d 100644
--- a/lib/Checker/Store.cpp
+++ b/lib/Checker/Store.cpp
@@ -270,3 +270,58 @@
return loc::MemRegionVal(MRMgr.getFieldRegion(cast<FieldDecl>(D), BaseR));
}
+
+SVal StoreManager::getLValueElement(QualType elementType, SVal Offset,
+ SVal Base) {
+
+ // If the base is an unknown or undefined value, just return it back.
+ // FIXME: For absolute pointer addresses, we just return that value back as
+ // well, although in reality we should return the offset added to that
+ // value.
+ if (Base.isUnknownOrUndef() || isa<loc::ConcreteInt>(Base))
+ return Base;
+
+ // Only handle integer offsets... for now.
+ if (!isa<nonloc::ConcreteInt>(Offset))
+ return UnknownVal();
+
+ const MemRegion* BaseRegion = cast<loc::MemRegionVal>(Base).getRegion();
+
+ // Pointer of any type can be cast and used as array base.
+ const ElementRegion *ElemR = dyn_cast<ElementRegion>(BaseRegion);
+
+ // Convert the offset to the appropriate size and signedness.
+ Offset = ValMgr.convertToArrayIndex(Offset);
+
+ if (!ElemR) {
+ //
+ // If the base region is not an ElementRegion, create one.
+ // This can happen in the following example:
+ //
+ // char *p = __builtin_alloc(10);
+ // p[1] = 8;
+ //
+ // Observe that 'p' binds to an AllocaRegion.
+ //
+ return loc::MemRegionVal(MRMgr.getElementRegion(elementType, Offset,
+ BaseRegion, Ctx));
+ }
+
+ SVal BaseIdx = ElemR->getIndex();
+
+ if (!isa<nonloc::ConcreteInt>(BaseIdx))
+ return UnknownVal();
+
+ const llvm::APSInt& BaseIdxI = cast<nonloc::ConcreteInt>(BaseIdx).getValue();
+ const llvm::APSInt& OffI = cast<nonloc::ConcreteInt>(Offset).getValue();
+ assert(BaseIdxI.isSigned());
+
+ // Compute the new index.
+ SVal NewIdx = nonloc::ConcreteInt(
+ ValMgr.getBasicValueFactory().getValue(BaseIdxI + OffI));
+
+ // Construct the new ElementRegion.
+ const MemRegion *ArrayR = ElemR->getSuperRegion();
+ return loc::MemRegionVal(MRMgr.getElementRegion(elementType, NewIdx, ArrayR,
+ Ctx));
+}