tree c826edb5e3a54bc7a0a8a15d59841ca3cd17754d
parent eab8a9f92dca9b8548a89d9e5eb6aeb8ac6bba77
author Takuto Ikuta <tikuta@google.com> 1777622264 +0900
committer gn-scoped@luci-project-accounts.iam.gserviceaccount.com <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1777624055 -0700

[gn] Bypass groups in order-only deps to use source set linkdeps

When a binary target depends on a group target, and that group target
depends on a source set with additional outputs (e.g., .dwo files), the
binary target previously ended up depending on the group target's phony
output. This caused the binary target to include the source set's
additional outputs in its order-only dependencies.

As established in commit a9f1a50154c7873b8152842dfd1392badeee55d6,
.linkdeps targets are used to avoid propagating non-object files like
.dwo to order-only dependencies. While .dwo files are generated
simultaneously with .o files (so they don't cause build delays), having
them in order-only dependencies causes problems for remote linking.
Specifically, it forces the upload of .dwo files to remote linkers,
leading to increased data transfer and potentially hitting file count
limits.

However, this isolation of .linkdeps was broken when a group target
acted as an intermediate dependency.

To fix this and respect the intent of
a9f1a50154c7873b8152842dfd1392badeee55d6, this commit modifies
NinjaCBinaryTargetWriter and NinjaRustBinaryTargetWriter to recursively
expand dependencies of group targets. If a group depends on a source
set, we now depend directly on its .linkdeps instead of the group
itself.

Bug: 502431091
Change-Id: Ia133f2048493a199ba8996332b9cbc3bb1591ca2
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/22400
Commit-Queue: Takuto Ikuta <tikuta@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>