[Lldb-commits] [PATCH] D151366: [lldb] Disable variable watchpoints when going out of scope

[Med Ismail Bennani via Phabricator via lldb-commits]

mib added a comment.

In D151366#4370123 <https://reviews.llvm.org/D151366#4370123>, @aprantl wrote:

> Just so I understand the limitations:
> This works for
>
>   int main() {
>     int val = 0;
>     // Break here
>     val++;
>     val++;
>     return 0;
>   }
>
> but not for
>
>   int main() {
>     {
>       int val = 0;
>       // Break here
>       val++;
>       val++;
>     }
>     {
>       int other = 42;
>       printf("assuming that other and val aliases");
>     }
>     return 0;
>   }
>
> ?
>
> To be clear, I think this is still useful!

@aprantl Do you know if we can detect the end of the scope ? I'm not sure it's possible currently ... But even if we could do it, that wouldn't cover the following case:

  int main() {
    int i = 0;
    {
  back_in_scope:
      int val = 0;
      i++;
      // Break here
      val++;
      val++;
    }
    {
      if (i == 1)
        goto back_in_scope;
      printf("assuming that other and val aliases");
    }
    return 0;
  }

If we disable the `val` variable watchpoint at the end of the scope, if we get back into it (because of a `goto` or whatever), the watchpoint won't trigger because it will disabled (by leaving the scope).

I think in order to solve these kind of problem we should do proper static analysis to be able to answer those questions.


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  https://reviews.llvm.org/D151366/new/

https://reviews.llvm.org/D151366