Makefile: Clean up .gcda files in prof-gen.

[LeiW000]

The .gcda files generated by "$(MAKE) PROF_FLAGS=-fprofile-generate all"
should be removed. Otherwise, the profile data in them would be combined
with the profile data of user's workload.Then, they would be used by
"make prof-use" later.

[LeiW000]

Can any maintainer help to trigger the workflows? This is my first PR in PHP. :).

[LeiW000]

Can anyone help to take look at the PR?

[Girgias]

I'm far from a build expert, and talking to someone else we had a quick look but don't know how to proceed with this.
Is the instructions to build such a build just a normal configure with make PROF_FLAGS="-fprofile-generate all"? and check the profiling with make prof-use?
If so I can try to make such a build myself and see if this works as intended, however, shouldn't this maybe be more part of a make clean procedure than just a make?

[cmb69]

If I understand correctly, the workflow is usually:

make prof-gen
# run workload
make prof-clean
make prof-use

If there are .gcda files right after make prof-gen (but before running the workload), these files should indeed be removed.

[LeiW000]

@cmb69 is right. User usually follows that workflow for PGO enabling. Currently, some .gcda files are generated after make prof-gen, because "php" is invoked during "make prof-gen".

[LeiW000]

I'm far from a build expert, and talking to someone else we had a quick look but don't know how to proceed with this. Is the instructions to build such a build just a normal configure with make PROF_FLAGS="-fprofile-generate all"? and check the profiling with make prof-use? If so I can try to make such a build myself and see if this works as intended, however, shouldn't this maybe be more part of a make clean procedure than just a make?

The "$(MAKE) PROF_FLAGS=-fprofile-generate all" is what is performed when "make prof-gen" is run. Please see line 136 in Makefile.global. If you want to test it yourself, you can run "make prof-gen". If you want to verify PGO, you can follow the steps, which @cmb69 provided in the comment.

[cmb69]

This looks good to me. Maybe someone who actually does PGO on a POSIX system can confirm.

[LeiW000]

Is there any other comment? If not, can the PR be merged now?

[LeiW000]

@cmb69, could you help to merge the PR? Or, do I have to contact another maintainer for merging?

[cmb69]

Thank you!