[Analyzer] Produce SymbolCast for pointer to integer cast

[martong]

Summary

Produce SymbolCast for a pointer-to-integer cast if the
support-symbolic-integer-casts flag is enabled.

[ASDenysPetrov]

clang/lib/StaticAnalyzer/Core/SValBuilder.cpp

1022

And it'd be great if you bring the original comment here, as the logic is here.

[martong]

• Move the comment hunk

clang/lib/StaticAnalyzer/Core/SValBuilder.cpp

1022

Ok, I've moved it.

[ASDenysPetrov]

clang/lib/StaticAnalyzer/Core/SValBuilder.cpp

1088

Notify the user about the contract.

1095–1097

Explain please, why do you need to create a new SymbolVal here, but not just returning V as long as you know that the type is the same?
And assert also seems weird for me. If there's smth obscure that you're trying to handle, please add some explaination comment.

[ASDenysPetrov]

clang/lib/StaticAnalyzer/Core/SValBuilder.cpp

1088

Mistake. CastTy, not SafeTy

[martong]

Thanks for the review Denys, and sorry for the long delay with the update. I hope that this patch is going to complement nicely the rest of the cast patches.

clang/lib/StaticAnalyzer/Core/SValBuilder.cpp

1088

Okay, I've added an assertion for this check.

1095–1097

You're right, we can just simply return V, I've updated like so. (I just wanted to make sure that the makeSymbolVal is consistent, but that has nothing to do with this patch.)

[martong]

• add new assert for canonical type
• remove superflous assert about makeSymbolVal