[PATCH] D103096: [analyzer] Implement cast for ranges of symbolic integers.

[Denys Petrov via Phabricator via cfe-commits]

ASDenysPetrov added a comment.

I found some issues. Working on improvement.



================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:2797-2799
+ProgramStateRef
+RangeConstraintManager::updateExistingConstraints(ProgramStateRef State,
+                                                  SymbolRef Sym, RangeSet R) {
----------------
vsavchenko wrote:
> OK, but I still don't understand one thing.
> Here you go over all "smaller" types and artificially create constraints for them, and at the same time in `VisitSymbolCast` you do the opposite operation?  Why?  Shouldn't the map have constraints for smaller types already because of this action?  Why do we need to do both?
> 
I've been preparing an answer for you, but suddenly you inspired me on some impovements. Thanks.


================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:2801-2802
+  // Get a root symbol in case of SymbolCast.
+  while (isa<SymbolCast>(Sym))
+    Sym = cast<SymbolCast>(Sym)->getOperand();
+
----------------
vsavchenko wrote:
> This looks like a pattern and we should probably make into a method of `SymbolCast`
I did it :) but refused. It will just turn into:
```
  if (isa<SymbolCast>(Sym))
    Sym = cast<SymbolCast>(Sym)->getRootOperand();
```
It looks pretty the same and brings no benefit IMO, does it?
Every time I used `getRootOperand` I also needed some additional traverse through the types te get some another information, so I couldn't avoid the `while` loop there. So I decided not to introduce a new method in `SymbolCast`.


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  https://reviews.llvm.org/D103096/new/

https://reviews.llvm.org/D103096