🐳 Move linux pkg_config() calls into separate BUILD.gn files

build/config/linux/BUILD.gn

Index: build/config/linux/BUILD.gn
diff --git a/build/config/linux/BUILD.gn b/build/config/linux/BUILD.gn
index c0871f881e7653c10684fc5ea73621ad551b6c2e..2a03b59478f7a39d370885da7439883832969283 100644
--- a/build/config/linux/BUILD.gn
+++ b/build/config/linux/BUILD.gn
@@ -3,9 +3,10 @@
 # found in the LICENSE file.
 
 import("//build/config/linux/pkg_config.gni")
-import("//build/config/features.gni")
-import("//build/config/sysroot.gni")
-import("//build/config/ui.gni")
+
+# Exists so that this file can referenced from //BUILD.gn.

[brettw, 2016/04/22 18:09:29]

Did you measure this? Now that all but one pkg_configs are gone, I wouldn't
expect much benefit. For the other case below, that one just has a config in it
and I don't really see how pulling that in early should make anything faster (so
definitely remove that one).

[agrieve, 2016/04/22 18:20:37]

Yep, this was a result of using gn gen -tracelog. For some reason these
pkg_config calls cause all other threads to be idle (there's a big white column
where these are the only things running). Even having just one call to
pkg_config causes the all-other-threads-idle thing to happen. Both this and the
posix one save 50ms by moving the one call earlier.

Is there a way to include a this file in the root BUILD.gn without having this
group? Maybe by having a dummy config() in //BUILD.gn?

[brettw, 2016/04/22 19:30:21]

Can you call this something like "optimize_gen_time" or something, and set
visibility to the one target that depends on this so people don't get confused?

[agrieve, 2016/04/25 14:45:35]

Like it. Done.

+group("linux") {
+}
 
 # This is included by reference in the //build/config/compiler config that
 # is applied to all targets. It is here to separate out the logic that is
@@ -29,47 +30,9 @@ config("runtime_library") {
 
 config("fontconfig") {
   visibility = [ "//build/linux:fontconfig" ]
-
   libs = [ "fontconfig" ]
 }
 
-pkg_config("freetype2") {
-  visibility = [ "//build/linux:freetype2" ]
-
-  packages = [ "freetype2" ]
-}
-
-pkg_config("glib") {
-  packages = [
-    "glib-2.0",
-    "gmodule-2.0",
-    "gobject-2.0",
-    "gthread-2.0",
-  ]
-}
-
-if (use_pango || use_cairo) {
-  pkg_config("pangocairo") {
-    packages = [ "pangocairo" ]
-  }
-}
-
-if (use_pango) {
-  pkg_config("pangoft2") {
-    packages = [ "pangoft2" ]
-  }
-}
-
-# Note: if your target also depends on //dbus, you don't need to add this
-# config (it will get added automatically if you depend on //dbus).
-pkg_config("dbus") {
-  packages = [ "dbus-1" ]
-}
-
-pkg_config("libffi") {
-  packages = [ "libffi" ]
-}
-
 config("x11") {
   libs = [
     "X11",
@@ -120,41 +83,11 @@ config("libresolv") {
   libs = [ "resolv" ]
 }
 
-# CrOS doesn't install GTK, gconf or any gnome packages.
-if (!is_chromeos && use_gconf) {
-  # These packages should _only_ be expected when building for a target.
-  # If these extra checks are not run, gconf is required when building host
-  # tools for a CrOS build.
-  if (current_toolchain == default_toolchain) {
-    pkg_config("atk") {
-      packages = [ "atk" ]
-      atk_lib_dir = exec_script(pkg_config_script,
-                                pkg_config_args + [
-                                      "--libdir",
-                                      "atk",
-                                    ],
-                                "string")
-      defines = [ "ATK_LIB_DIR=\"$atk_lib_dir\"" ]
-    }
-
-    # gn orders flags on a target before flags from configs. The default config
-    # adds -Wall, and these flags have to be after -Wall -- so they need to
-    # come from a config and can't be on the target directly.
-    config("atk_warnings") {
-      cflags = [
-        # glib uses the pre-c++11 typedef-as-static_assert hack.
-        "-Wno-unused-local-typedef",
-
-        # G_DEFINE_TYPE automatically generates a *get_instance_private
-        # inline function after glib 2.37. That's unused. Prevent to
-        # complain about it.
-        "-Wno-unused-function",
-      ]
-    }
-
-    pkg_config("gconf") {
-      packages = [ "gconf-2.0" ]
-      defines = [ "USE_GCONF" ]
-    }
-  }
+pkg_config("glib") {
+  packages = [
+    "glib-2.0",
+    "gmodule-2.0",
+    "gobject-2.0",
+    "gthread-2.0",
+  ]
 }