[PATCH] D29203: Change debug-info-for-profiling from a TargetOption to a function attribute.

[Dehao Chen via Phabricator via llvm-commits]

danielcdh added a comment.

In https://reviews.llvm.org/D29203#659019, @mehdi_amini wrote:

> In https://reviews.llvm.org/D29203#658997, @danielcdh wrote:
>
> > - What is the motivating example that you want to compile some sources with -fdebug-info-for-profiling and some without
> >   - If the debug info size is a concern for -gmlt binary, then one would want to only enable this flag for sources that is performance-critical
>
>
> This is an argument *against* a module flag.


Right ;-) I think I need to raise the point before close the patch.

But my opinion is that this use cases (if any) would be rare because:

- 17% seem small, but people may have other opinions
- adding per-CU flag is manual and tedious
- per-CU flag may need to change as new source coming in/old source change that updates the hot CU distribution

That being said, I would think it's better to force this flag in LTO when mixed flag situation happens. But will let upstream decide if this would be a feature or a bug.

Thanks,
Dehao


https://reviews.llvm.org/D29203