Rework approach to allowing extra flags for CrOS builds.

build/toolchain/cros/BUILD.gn

Index: build/toolchain/cros/BUILD.gn
diff --git a/build/toolchain/cros/BUILD.gn b/build/toolchain/cros/BUILD.gn
index 0149ce52f33c32a6e581006cf746fb67d00ecc53..397c7c2e25b55fe0361b5fb2242b681a16324928 100644
--- a/build/toolchain/cros/BUILD.gn
+++ b/build/toolchain/cros/BUILD.gn
@@ -22,10 +22,6 @@ gcc_toolchain("target") {
   if (cros_target_readelf != "") {
     readelf = cros_target_readelf
   }
-  extra_cflags = cros_target_extra_cflags
-  extra_cppflags = cros_target_extra_cppflags
-  extra_cxxflags = cros_target_extra_cxxflags
-  extra_ldflags = cros_target_extra_ldflags
 
   # These are passed through as toolchain_args.
   cc_wrapper = ""
@@ -55,10 +51,6 @@ gcc_toolchain("nacl_bootstrap") {
   if (cros_target_readelf != "") {
     readelf = cros_target_readelf
   }
-  extra_cflags = cros_nacl_bootstrap_extra_cflags
-  extra_cppflags = cros_nacl_bootstrap_extra_cppflags
-  extra_cxxflags = cros_nacl_bootstrap_extra_cxxflags
-  extra_ldflags = cros_nacl_bootstrap_extra_ldflags
 
   # These are passed through as toolchain_args.
   cc_wrapper = ""
@@ -85,10 +77,6 @@ gcc_toolchain("host") {
   if (cros_host_readelf != "") {
     readelf = cros_host_readelf
   }
-  extra_cflags = cros_host_extra_cflags
-  extra_cppflags = cros_host_extra_cppflags
-  extra_cxxflags = cros_host_extra_cxxflags
-  extra_ldflags = cros_host_extra_ldflags
 
   # These are passed through as toolchain_args.
   cc_wrapper = ""
@@ -113,10 +101,6 @@ gcc_toolchain("v8_snapshot") {
   if (cros_v8_snapshot_readelf != "") {
     readelf = cros_v8_snapshot_readelf
   }
-  extra_cflags = cros_v8_snapshot_extra_cflags
-  extra_cppflags = cros_v8_snapshot_extra_cppflags
-  extra_cxxflags = cros_v8_snapshot_extra_cxxflags
-  extra_ldflags = cros_v8_snapshot_extra_ldflags
 
   # These are passed through as toolchain_args.
   cc_wrapper = ""
@@ -130,3 +114,30 @@ gcc_toolchain("v8_snapshot") {
   toolchain_os = "linux"
   use_sysroot = false
 }
+
+config("extra_flags") {

[brettw, 2016/08/03 23:02:14]

This should really be in //build/config/cros/BUILD.gn. It doesn't exist yet, but
the toolchain dirs don't define configs or set flags, those go in build/config.

[Dirk Pranke, 2016/08/03 23:09:07]

Good point. I'll move it.

+  if (current_toolchain == "//build/toolchain/cros:target") {
+    cflags = cros_target_extra_cflags
+    cppflags = cros_target_extra_cppflags
+    cxxflags = cros_target_extra_cxxflags
+    ldflags = cros_target_extra_ldflags
+  } else if (current_toolchain == "//build/toolchain/cros:host") {
+    cflags = cros_host_extra_cflags
+    cppflags = cros_host_extra_cppflags
+    cxxflags = cros_host_extra_cxxflags
+    ldflags = cros_host_extra_ldflags
+  } else if (current_toolchain == "//build/toolchain/cros:v8_snapshot") {
+    cflags = cros_v8_snapshot_extra_cflags
+    cppflags = cros_v8_snapshot_extra_cppflags
+    cxxflags = cros_v8_snapshot_extra_cxxflags
+    ldflags = cros_v8_snapshot_extra_ldflags
+  } else if (current_toolchain == "//build/toolchain/cros:nacl_bootstrap") {
+    cflags = cros_nacl_bootstrap_extra_cflags
+    cppflags = cros_nacl_bootstrap_extra_cppflags
+    cxxflags = cros_nacl_bootstrap_extra_cxxflags
+    ldflags = cros_nacl_bootstrap_extra_ldflags
+  } else {
+    assert(false,
+           "Unexpected reference to this config from " + current_toolchain)
+  }
+}