[all-commits] [llvm/llvm-project] 4cf7f3: [Coro] Use DebugInfoCache to speed up cloning in C...

[Artem Pianykh via All-commits]

  Branch: refs/heads/users/artempyanykh/fast-coro-upstream/11
  Home:   https://github.com/llvm/llvm-project
  Commit: 4cf7f3f62a96e99a7d9d5b4c32d4267da0ed44b4
      https://github.com/llvm/llvm-project/commit/4cf7f3f62a96e99a7d9d5b4c32d4267da0ed44b4
  Author: Artem Pianykh <arr at fb.com>
  Date:   2024-09-15 (Sun, 15 Sep 2024)

  Changed paths:
    M llvm/include/llvm/Transforms/Coroutines/ABI.h
    M llvm/lib/Analysis/CGSCCPassManager.cpp
    M llvm/lib/Transforms/Coroutines/CoroSplit.cpp
    M llvm/test/Other/new-pass-manager.ll
    M llvm/test/Other/new-pm-defaults.ll
    M llvm/test/Other/new-pm-lto-defaults.ll
    M llvm/test/Other/new-pm-pgo-preinline.ll
    M llvm/test/Other/new-pm-thinlto-postlink-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-pgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-samplepgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-pgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-samplepgo-defaults.ll
    M llvm/unittests/Analysis/CGSCCPassManagerTest.cpp

  Log Message:
  -----------
  [Coro] Use DebugInfoCache to speed up cloning in CoroSplitPass

Summary:
We can use a DebugInfoFinder from DebugInfoCache which is already primed on a compile unit to speed
up collection of global debug info.

The pass could likely be another 2x+ faster if we avoid rebuilding the set of global debug
info. This needs further massaging of CloneFunction and ValueMapper, though, and can be done
incrementally on top of this.

Comparing performance of CoroSplitPass at various points in this stack, this is anecdata from a sample
cpp file compiled with full debug info:
|                 | Baseline | IdentityMD set | Prebuilt GlobalDI | Cached CU DIFinder (cur.) |
|-----------------+----------+----------------+-------------------+---------------------------|
| CoroSplitPass   | 306ms    | 221ms          | 68ms              | 17ms                      |
| CoroCloner      | 101ms    | 72ms           | 0.5ms             | 0.5ms                     |
| CollectGlobalDI | -        | -              | 63ms              | 13ms                      |
|-----------------+----------+----------------+-------------------+---------------------------|
| Speed up        | 1x       | 1.4x           | 4.5x              | 18x                       |

Test Plan:
ninja check-llvm-unit
ninja check-llvm

Compiled a sample cpp file with time trace to get the avg. duration of the pass and inner scopes.

stack-info: PR: https://github.com/llvm/llvm-project/pull/118630, branch: users/artempyanykh/fast-coro-upstream/11



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