From a3f0da56e4c9cfe22f6be29ff8dd8b9d2c059016 Mon Sep 17 00:00:00 2001
From: David Turner <52076061+digit-google@users.noreply.github.com>
Date: Wed, 23 Oct 2019 16:07:19 +0200
Subject: [PATCH] BUILD.gn: Fix fuchsia build (#1944)

The Fuchsia platform build and the Chromium one use a completely
different set of configs to specify default warnings. The previous
version of BUILD.gn worked with Chromium, but failed to build
with Fuchsia.

This CL fixes the issue by identifying said configs and reusing
them consistently.

Change-Id: I7de526a57d2f14eb93c03e06401d2c3059d35e9a
---
 BUILD.gn | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/BUILD.gn b/BUILD.gn
index 77d596e1..3351fd3e 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -33,6 +33,19 @@
 
 import("//build_overrides/glslang.gni")
 
+# Both Chromium and Fuchsia use by default a set of warning errors
+# that is far too strict to compile this project. These are also
+# typically appended after |cflags|, overriding target-specific
+# definitions. To work around this, determine which configs to
+# add and remove in order to succesfully build the project.
+if (defined(is_fuchsia_tree) && is_fuchsia_tree) {
+  _configs_to_remove = [ "//build/config:default_warnings" ]
+  _configs_to_add = []
+} else {
+  _configs_to_remove = [ "//build/config/compiler:chromium_code" ]
+  _configs_to_add = [ "//build/config/compiler:no_chromium_code" ]
+}
+
 spirv_tools_dir = glslang_spirv_tools_dir
 
 config("glslang_public") {
@@ -182,8 +195,8 @@ source_set("glslang_sources") {
     "${spirv_tools_dir}:spvtools_val",
   ]
 
-  configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
+  configs -= _configs_to_remove
+  configs += _configs_to_add
 }
 
 source_set("glslang_default_resource_limits_sources") {
@@ -196,8 +209,8 @@ source_set("glslang_default_resource_limits_sources") {
   ]
   public_configs = [ ":glslang_public" ]
 
-  configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
+  configs -= _configs_to_remove
+  configs += _configs_to_add
 }
 
 executable("glslang_validator") {
@@ -214,8 +227,8 @@ executable("glslang_validator") {
     ":glslang_sources",
   ]
 
-  configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
+  configs -= _configs_to_remove
+  configs += _configs_to_add
 }
 
 executable("spirv-remap") {
@@ -227,6 +240,6 @@ executable("spirv-remap") {
     ":glslang_sources",
   ]
 
-  configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
+  configs -= _configs_to_remove
+  configs += _configs_to_add
 }