[all-commits] [llvm/llvm-project] 325e7e: [LLVM][LTO][LLD] Enable Profile Guided Layout (--c...

[bd1976bris via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 325e7e8b87423f83ba9fc53b9486ce67329d486c
      https://github.com/llvm/llvm-project/commit/325e7e8b87423f83ba9fc53b9486ce67329d486c
  Author: Ben Dunbobbin <Ben.Dunbobbin at sony.com>
  Date:   2022-07-01 (Fri, 01 Jul 2022)

  Changed paths:
    M clang/test/CodeGen/thinlto-distributed-newpm.ll
    M llvm/lib/Passes/PassBuilderPipelines.cpp
    M llvm/test/Other/new-pm-defaults.ll
    M llvm/test/Other/new-pm-lto-defaults.ll
    M llvm/test/Other/new-pm-thinlto-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-pgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-samplepgo-defaults.ll

  Log Message:
  -----------
  [LLVM][LTO][LLD] Enable Profile Guided Layout (--call-graph-profile-sort) for FullLTO

The CGProfilePass needs to be run during FullLTO compilation at link
time to emit the .llvm.call-graph-profile section to the compiled LTO
object file. Currently, it is being run only during the initial
LTO-prelink compilation stage (to produce the bitcode files to be
consumed by the linker) and so the section is not produced.

ThinLTO is not affected because:
- For ThinLTO-prelink compilation the CGProfilePass pass is not run
  because ThinLTO-prelink passes are added via
  buildThinLTOPreLinkDefaultPipeline. Normal and FullLTO-prelink
  passes are both added via buildPerModuleDefaultPipeline which uses
  the LTOPreLink parameter to customize its behavior for the
  FullLTO-prelink pass differences.
- ThinLTO backend compilation phase adds the CGProfilePass (see:
  buildModuleOptimizationPipeline).

Adjust when the pass is run so that the .llvm.call-graph-profile
section is produced correctly for FullLTO.

Fixes #56185 (https://github.com/llvm/llvm-project/issues/56185)