| # 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. |
