[all-commits] [llvm/llvm-project] 78eb7e: [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: 78eb7e9f3f0e4419056031e31b4e3ea4b1e52079
      https://github.com/llvm/llvm-project/commit/78eb7e9f3f0e4419056031e31b4e3ea4b1e52079
  Author: Artem Pianykh <arr at fb.com>
  Date:   2025-01-30 (Thu, 30 Jan 2025)

  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 module-level debug info.

The pass could likely be another 2x+ faster if we avoid rebuilding the set of common 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 CommonDI | Cached CU DIFinder (cur.) |
|-----------------|----------|----------------|-------------------|---------------------------|
| CoroSplitPass   | 306ms    | 221ms          | 68ms              | 17ms                      |
| CoroCloner      | 101ms    | 72ms           | 0.5ms             | 0.5ms                     |
| CollectCommonDI | -        | -              | 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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