steakhal updated this revision to Diff 281556.
steakhal marked 3 inline comments as done.
steakhal added a comment.
Reworked `ElementRegion` handling.
Previously it handled only element regions in the form of: `Element{X,n} OP
Element{X,m}`
Now supports `Element{X,n} OP X` and `X OP Element{X,n}` as well.
Still misses nested ElementRegions though like: `Element{X,n} OP
Element{Element{X,k},m}`.
No tests yet.
Regression test vs unit test - which should I prefer?
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D84736/new/
https://reviews.llvm.org/D84736
Files:
clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
Index: clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -1017,40 +1017,77 @@
}
}
- // Handle special cases for when both regions are element regions.
- const ElementRegion *RightER = dyn_cast<ElementRegion>(RightMR);
- const ElementRegion *LeftER = dyn_cast<ElementRegion>(LeftMR);
- if (RightER && LeftER) {
- // Next, see if the two ERs have the same super-region and matching types.
- // FIXME: This should do something useful even if the types don't match,
- // though if both indexes are constant the RegionRawOffset path will
- // give the correct answer.
- if (LeftER->getSuperRegion() == RightER->getSuperRegion() &&
- LeftER->getElementType() == RightER->getElementType()) {
- // Get the left index and cast it to the correct type.
- // If the index is unknown or undefined, bail out here.
- SVal LeftIndexVal = LeftER->getIndex();
- Optional<NonLoc> LeftIndex = LeftIndexVal.getAs<NonLoc>();
- if (!LeftIndex)
- return UnknownVal();
- LeftIndexVal = evalCastFromNonLoc(*LeftIndex, ArrayIndexTy);
- LeftIndex = LeftIndexVal.getAs<NonLoc>();
- if (!LeftIndex)
+ // Handle: \forall MemRegion X, \forall NonLoc n, m:
+ // - Element{X,n} OP Element{X,m}
+ // - Element{X,n} OP X
+ // - X OP Element{X,n}
+ // We don't handle here nested ElementRegions like in the this expression:
+ // Element{Element{x,3,int [10]},5,int} == Element{x,35,int}
+ {
+ // Calculates the byte offset within the memory region to the referred
+ // element.
+ const auto ByteOffsetOfElement =
+ [this, state](const ElementRegion *ElemReg) -> NonLoc {
+ NonLoc Index = evalCastFromNonLoc(ElemReg->getIndex(), ArrayIndexTy)
+ .castAs<NonLoc>();
+ CharUnits SingleElementSize =
+ ElemReg->getContext().getTypeSizeInChars(ElemReg->getElementType());
+ return evalBinOpNN(state, BO_Mul, Index,
+ makeArrayIndex(SingleElementSize.getQuantity()),
+ ArrayIndexTy)
+ .castAs<NonLoc>();
+ };
+
+ // If both has the same memory region, and the index has a concrete value,
+ // we can evaluate equality operators.
+ const auto EvaluateEqualityOperators =
+ [this, state, op, resultTy](NonLoc Index,
+ bool HasSameMemRegions) -> SVal {
+ assert(BinaryOperator::isEqualityOp(op));
+ const llvm::APSInt *Int = getKnownValue(state, Index);
+ if (!Int)
return UnknownVal();
- // Do the same for the right index.
- SVal RightIndexVal = RightER->getIndex();
- Optional<NonLoc> RightIndex = RightIndexVal.getAs<NonLoc>();
- if (!RightIndex)
- return UnknownVal();
- RightIndexVal = evalCastFromNonLoc(*RightIndex, ArrayIndexTy);
- RightIndex = RightIndexVal.getAs<NonLoc>();
- if (!RightIndex)
- return UnknownVal();
+ const bool EQResult = HasSameMemRegions && *Int == 0;
+ return makeTruthVal(op == BO_EQ ? EQResult : !EQResult, resultTy);
+ };
+
+ const ElementRegion *RightER = dyn_cast<ElementRegion>(RightMR);
+ const ElementRegion *LeftER = dyn_cast<ElementRegion>(LeftMR);
+ if (RightER && LeftER) {
+ // Next, see if the two ERs have the same super-region and matching
+ // types.
+ // FIXME: This should do something useful even if the types don't match,
+ // though if both indexes are constant the RegionRawOffset path will
+ // give the correct answer.
+ if (LeftER->getSuperRegion() == RightER->getSuperRegion() &&
+ LeftER->getElementType() == RightER->getElementType()) {
+ return evalBinOpNN(state, op, ByteOffsetOfElement(LeftER),
+ ByteOffsetOfElement(RightER), resultTy);
+ }
+ } else if (LeftER && !RightER) {
+ NonLoc LeftIndex = ByteOffsetOfElement(LeftER);
+ const bool HasSameMemRegions = LeftER->getSuperRegion() == RightMR;
- // Actually perform the operation.
- // evalBinOpNN expects the two indexes to already be the right type.
- return evalBinOpNN(state, op, *LeftIndex, *RightIndex, resultTy);
+ if (BinaryOperator::isEqualityOp(op))
+ return EvaluateEqualityOperators(LeftIndex, HasSameMemRegions);
+
+ if (op == BO_Sub && HasSameMemRegions)
+ return LeftIndex;
+ return UnknownVal();
+ } else if (!LeftER && RightER) {
+ NonLoc RightIndex = ByteOffsetOfElement(RightER);
+ const bool HasSameMemRegions = LeftMR == RightER->getSuperRegion();
+
+ if (BinaryOperator::isEqualityOp(op))
+ return EvaluateEqualityOperators(RightIndex, HasSameMemRegions);
+
+ // FIXME: Consider refactoring evalMinus function to accept the State
+ // as well, and use it here.
+ if (op == BO_Sub && HasSameMemRegions)
+ return evalBinOpNN(state, BO_Sub, makeZeroArrayIndex(), RightIndex,
+ ArrayIndexTy);
+ return UnknownVal();
}
}
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