vsavchenko marked 3 inline comments as done.
vsavchenko added a comment.
Hi @ASDenysPetrov no problem at all! Thanks for taking your time and checking
it.
================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:367-378
+RangeSet RangeSet::Delete(BasicValueFactory &BV, Factory &F,
+ const llvm::APSInt &Point) const {
+ llvm::APSInt Upper = Point;
+ llvm::APSInt Lower = Point;
+
+ ++Upper;
+ --Lower;
----------------
ASDenysPetrov wrote:
> Useful function. But I'd better rename it to `subtract` as we are working
> with sets (as a mathimatical collection). We should have a such one for the
> Ranges not only for Points.
> We have `intersect`, `delete` aka `subtract`. And we also need to have
> functions `union` and `symmetricDifference` to cover full palette of common
> operations on sets.
I agree that we should have a full set of functions. I don't agree however,
that this function is a `subtract`. Subtract is an operation on two sets and
here we have a set and a point. One might argue that a point is just a very
simple set, that's true, but real `subtract` would be more complex in its
implementation.
Naming it `delete`, on the other hand, I was coming from a notion of deleting
points or neighbourhoods
(https://en.wikipedia.org/wiki/Neighbourhood_(mathematics)#Deleted_neighbourhood).
================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:734
// expressions which we currently do not know how to negate.
- const RangeSet *getRangeForMinusSymbol(ProgramStateRef State, SymbolRef Sym)
{
+ Optional<RangeSet> getRangeForInvertedSub(SymbolRef Sym) {
if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(Sym)) {
----------------
ASDenysPetrov wrote:
> As for me, I'd call this like `getRangeForNegatedSymSymExpr`, since you do
> Negate operation inside.
I'm not super happy about my name either, but I feel like it describes it
better than the previous name and your version. That function doesn't work for
any `SymSymExpr` and it doesn't simply negate whatever we gave it. It works
specifically for symbolic subtractions and this is the information I want to be
reflected in the name.
================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:841-844
+ RangeSet getTrueRange(QualType T) {
+ RangeSet TypeRange = infer(T);
+ return assumeNonZero(TypeRange, T);
+ }
----------------
ASDenysPetrov wrote:
> Don't you think this is too complicated for such a simple getter?
> Maybe we can just construct the range using smth about
> `RangeSet(RangeFactory, ++Zero, --Zero);` ?
It is more complex than a false range but there is a reason for it.
First of all, `RangeSet` can't have ranges where the end is greater than its
start. Only `Intersect` can handle such ranges correctly. Another thing is
that ranges like that mean `[MIN, --Zero], [++Zero, MAX]` and without a type we
can't really say what `MIN` and `MAX` are, so such constructor for `RangeSet`
simply cannot exist.
Another point is that we do need to have `[MIN, -1], [+1, MAX]` as opposed to
`[-1, -1], [+1, +1]` because of C language (it doesn't have boolean type), and
because of the cases like `a - b` where we know that `a != b`.
I hope that answers the question.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D82381/new/
https://reviews.llvm.org/D82381
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