tree bc2adf2a5842fc9def1856804eb0c9340dd156a4
parent 9d19a7870add65151ff91bcc26252bb7521065cf
author Takuto Ikuta <tikuta@google.com> 1771422485 +0900
committer GN LUCI <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1771424413 -0800

[perf] Optimize HeaderChecker BFS using reserve()

This optimization adds breadcrumbs.reserve() to
HeaderChecker::IsDependencyOf to reduce the number of rehashes in the
visited nodes map during BFS.

Performance Impact (Chromium 'gn gen --check' on macOS):
- Baseline (origin/main): 66.5s ± 0.4s
- With this change: 58.1s ± 0.6s (approx. 13% faster)

Bug: 484862257
Change-Id: I4e011f8539e4b2a9343d25f12898a3bc2ab23a93
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/21080
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: David Turner <digit@google.com>
Reviewed-by: David Turner <digit@google.com>