RFC: Should the linker support '--fast' and if so, what should it do ?

[Jan Beulich]

On 25.03.2026 14:31, Nick Clifton wrote:
>    Attached is a proposed patch to implement "-O 0" as a command line option
>    that disables merging.
> 
>    The patch does change the linker's default behaviour, albeit in a small way:
>    It changes the linker's nominal default optimization level to 1 instead of 0,
>    so that in order to gain the enable-heavy-optimization effect you need to link
>    with "0O 2" (or higher) whereas before "-O 1" would have also done this.  (With
>    the patch applied "-O 1" now restores the linker's default behaviour of neither
>    optimizing nor skipping the merge stage).
> 
>    Thoughts ?

I'm not entirely happy with forcing people to change the -O uses they may have.
But perhaps that's tolerable. A possible alternative might be to support -O- to
have the effect of setting optimize_level to 0, while -O <number> would set it
to <number>+1. Yet of course -O0 has widely known meaning ...

I'm also uncertain as to the two "high cost" optimizations that you now move to
-O2. Are they really high cost?

The doc change may want to be a little less ELF-centric. Inserting "e.g." may
already suffice to address that.

--help output could do with also stating the default.

Perhaps not for this patch, but the handling of -O could also do with some
improvement. "-O --help", for example, better wouldn't do what it does now.

Jan