| commit | 3eb2f51592df07c2008f6ec2aa357764caaf0239 | [log] [tgz] |
|---|---|---|
| author | Googler <noreply@google.com> | Tue Apr 09 09:54:01 2019 -0700 |
| committer | Copybara-Service <copybara-worker@google.com> | Tue Apr 09 09:55:55 2019 -0700 |
| tree | 421669269de2561d7cdc9153bfbff8162f6dbbdc | |
| parent | 8d24345cddc0632979f5153618b2254d5aac8357 [diff] |
Add the support to LLVM's Context Sensitive FDO
LLVM recently implemented Context Sensitive FDO/PGO (CSFDO/CSPGO) which uses a
post-inline instrumentation to record more accurate profile information for the
inlined code. It improves the effectiveness of post-inline optimizations.
This CL adds the support to CSFDO:
(1) Add new options:
--cs_fdo_instrument=<csfdo_instru_path>,
--cs_profile=<csfdo_label>
(2) Add two features: CS_FDO_INSTRUMENT and CS_FDO_OPTIMIZE.
(2) Add a new BranchFdoMode: LLVM_CS_FDO.
(3) Merge CSFDO profile and regular FDO profile.
(4) Pass CSFDO options to the back-end invocations.
(5) Distribute the profile to build hosts in LLVM_CS_FDO optimize build. This is
not needed for regular FDO as the profile is read in during pre-LTO passes. We
need this step in CSFDO because the profile is read-in and used in the back-end.
RELNOTES: Add new options --cs_fdo_instrument and --cs_profile to support
LLVM's context-sensitive FDO (CSFDO).
PiperOrigin-RevId: 242685802
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