tree 98a3e4fe3afc331aab667b057e75ba280214d57a
parent 11777fd3e509b2835ffdb901c1bf1744651ba314
author Takuto Ikuta <tikuta@google.com> 1777366257 +0900
committer gn-scoped@luci-project-accounts.iam.gserviceaccount.com <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1777387952 -0700

[gn] Split SOURCE_SET phony targets to exclude additional outputs from linking

Split the phony target generated for a `source_set` into two targets:
1. The default phony target (e.g., `phony/foo/bar`) which depends on
both object files and additional outputs (like `.dwo` files).
2. A link-only phony target (e.g., `phony/foo/bar.linkdeps`) which
depends only on object files.

When other targets depend on this `source_set`, they will now use the
`.linkdeps` suffixed target for their order-only dependencies.

This is important for build systems like Siso that support remote
linking. If the link step indirectly depends on `.dwo` files through the
phony target, Siso might include those `.dwo` files as inputs for the
remote link command. Since `.dwo` files are only needed for debugging
and not for linking, uploading them would be a waste of bandwidth and
time. By splitting the phony target, we prevent `.dwo` files from being
included as inputs for the link step.

Bug: 502431091
Change-Id: I574063a57f537a2c5f9662bb39202ecc4cf92761
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/22160
Commit-Queue: David Turner <digit@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
Reviewed-by: David Turner <digit@google.com>