tree 91c5d4ca1424da4c71ec84f3780820903410f5b3
parent 5550ba0f4053c3cbb0bff3d60ded9d867b6fa371
author Greg Thompson <grt@chromium.org> 1766404371 +0100
committer GN LUCI <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1768033294 -0800

Improve writing runtime deps

- Due to a bug, the `found_files` set was never actually used to omit
  duplicate deps. Since this apparently has never been an issue in
  practice, remove the set and mention of it from comments.
- Use a std::unordered_map for `seen_targets` to trade memory for speed.
- Avoid a redundant lookup in `seen_targets` when a target is already
  present.
- Use emplace facilities in favor of copy/move where appropriate.
- When calling WriteRuntimeDepsFile, stream the deps directly to the
  output buffer rather than accumulating them in a vector and then
  writing from the vector into the output buffer.
- Parallelize collecting/writing the runtime deps files.

This reduces overall runtime by about 9% on my workstation.

Change-Id: Ic5a10415348345a6f9473613b4391281d9e20605
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/20700
Commit-Queue: Greg Thompson <grt@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@google.com>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>