Tell shaderc where to find SPIRV-Cross.

Set a variable in build_overrides that gives the location of shaderc's
new SPIRV-Cross dependency.  The variable will take a different value
for a dawn stand-alone build.

BUG=915096

Change-Id: Ied39c0b233de2c3e8ea29b576759c4c4eb8b0a61
Reviewed-on: https://chromium-review.googlesource.com/c/1378009
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#616754}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c0fd077dcd55a26ea05eedc16cad0d3693ac33cf
1 file changed
tree: 1e9d29ca6155ee281a6ab369194edf7dbfc261f0
  1. OWNERS
  2. README.md
  3. build.gni
  4. dawn.gni
  5. glslang.gni
  6. gtest.gni
  7. pdfium.gni
  8. shaderc.gni
  9. spirv_tools.gni
README.md

Build overrides in GN

This directory is used to allow different products to customize settings for repos that are DEPS'ed in or shared.

For example: V8 could be built on its own (in a “standalone” configuration), and it could be built as part of Chromium. V8 might define a top-level target, //v8:d8 (a simple executable), that should only be built in the standalone configuration. To figure out whether or not it should be in a standalone configuration, v8 can create a file, build_overrides/v8.gni, that contains a variable, build_standalone_d8 = true. and import it (as import(“//build_overrides/v8.gni”) from its top-level BUILD.gn file.

Chromium, on the other hand, might not need to build d8, and so it would create its own build_overrides/v8.gni file, and in it set build_standalone_d8 = false.

The two files should define the same set of variables, but the values can vary as appropriate to the needs of the two different builds.

The build.gni file provides a way for projects to override defaults for variables used in //build itself (which we want to be shareable between projects).

TODO(crbug.com/588513): Ideally //build_overrides and, in particular, //build_overrides/build.gni should go away completely in favor of some mechanism that can re-use other required files like //.gn, so that we don't have to keep requiring projects to create a bunch of different files to use GN.