Re: State of AutoFDO in GCC

[Andi Kleen <ak@linux.intel.com>]

On Mon, May 10, 2021 at 04:55:50PM +0000, Joseph Myers wrote:
> On Mon, 10 May 2021, Andi Kleen via Gcc wrote:
> 
> > It's difficult to find now because it was a branch in the old SVN that wasn't
> > converted. Sadly the great git conversion was quite lossy.
> 
> All branches and tags, including deleted ones, were converted (under 
> not-fetched-by-default refs in some cases); the git repository has 
> everything that might plausibly be useful, omitting only a few things that 
> would have been meaningless to convert, such as mistaken branch creations 
> in the root of the repository and the SVN hooks directory.  Use "git 
> ls-remote git://gcc.gnu.org/git/gcc.git" to see the full list of over 5000 
> refs available in the repository (or do a clone with --mirror to fetch 
> them all).

Okay thanks. I don't see them in any of the web interfaces, neither on
https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git
nor on
https://github.com/gcc-mirror/gcc
but 
git fetch origin vendors/google/heads/gcc-4_8
does the trick for fetching the commits, but not the symbolic branches.

Anyways with that it looks like the discriminator changes are:

commit fd9de90d750e3588b1e5a218b28102b6c8bb8434
Author: Dehao Chen <dehao@gcc.gnu.org>
Date:   Thu Oct 10 14:39:31 2013 +0000

    Use only lineno+discriminator (remove the callee function name) as the key to represent callsite. Because each callsite will have its discriminator if in the same line.

    2013-10-10  Dehao Chen  <dehao@google.com>

            * gcc/auto-profile.c (get_function_instance_by_decl): Remove
            callee_name from callsite.
            (read_function_instance): Likewise.

    From-SVN: r203379

commit 3987da76affbfbe7195c0a16b33beedc649ec14f
Author: Dehao Chen <dehao@gcc.gnu.org>
Date:   Tue Aug 27 16:46:49 2013 +0000

    Refactor AutoFDO to:

    1. Now that we have discriminator for inlined callsite, we do not need special handling for callsite location any more.
    2. If a source line is mapped to multiple BBs, only the first BB will be annotated.
    3. Before actual annotation, mark everythin BB/edge as not annotated.

    2013-08-27  Dehao Chen  <dehao@google.com>

            * gcc/auto-profile.c (location_set): New data structure.
            (get_count_info): Add new parameter.
            (get_combined_location): Remove unused parameter.
            (get_inline_stack): Remove unused parameter.
            (afdo_get_bb_count): Add new parameter.
            (afdo_annotate_cfg): Reset annotated flags.
commit 1e6c4a7a8fb8e20545bb9f9032d3854f3f794c18
Author: Dehao Chen <dehao@gcc.gnu.org>
Date:   Thu Aug 22 17:20:29 2013 +0000

    Set discriminator for call stmts within a same basic block.

    2013-08-22  Dehao Chen  <dehao@google.com>

            * gcc/tree-cfg.c (assign_discriminators): assign discriminator for
            call stmt in a same BB if it is mapped to a same line.

commit b0be0175f4cf18fdd77bb013b181eead3a0a4773
Author: Dehao Chen <dehao@gcc.gnu.org>
Date:   Mon Aug 19 21:26:33 2013 +0000

    Fix the discriminator assignment bug during hashing.

    2013-08-19  Dehao Chen  <dehao@google.com>

            * tree-cfg.c (next_discriminator_for_locus): Fix discriminator
            assignment bug.

    From-SVN: r201857
commit 9fa26998a63d4b22b637ed8702520819e408a694
Author: Dehao Chen <dehao@gcc.gnu.org>
Date:   Mon Aug 19 20:16:47 2013 +0000

    Add discrminator for inlined callsites.

    2013-08-19  Dehao Chen  (dehao@google.com)

            * include/dwarf2.def (DW_AT_GNU_discriminator): New attribute.
            * gcc/dwarf2out.c (add_call_src_coords_attributes): Emit discriminator
            attribute for inlined callsite.

    From-SVN: r201856

-Andi