Cherry pick PR #1743: Enable modular build for gcc 6.3

.github/config/linux-gcc-6-3.json

@@ -1,5 +1,7 @@
 {
   "docker_service": "build-linux-gcc",
+  "on_host_test": true,
+  "on_host_test_shards": ["0", "1", "2", "3", "blackbox", "wpt"],
   "platforms": [
     "linux-x64x11-gcc-6-3"
   ],
@@ -8,7 +10,7 @@
       "name":"gcc-6-3",
       "platform":"linux-x64x11-gcc-6-3",
       "target_platform":"linux-x64x11-gcc-6-3",
-      "extra_gn_arguments":"is_clang=false using_old_compiler=true"
+      "extra_gn_arguments":"using_old_compiler=true build_with_separate_cobalt_toolchain=true"
     }
   ]
 }

.github/workflows/linux_24.lts.1+.yaml

@@ -45,6 +45,7 @@ jobs:
     with:
       platform: linux-gcc-6-3
       nightly: ${{ github.event.inputs.nightly }}
+      modular: true
   # TODO(b/285632780): Enable blackbox tests for modular linux workflows.
   linux-modular:
     uses: ./.github/workflows/main.yaml

starboard/linux/x64x11/gcc/6.3/BUILD.gn

@@ -27,3 +27,9 @@ static_library("starboard_platform") {
 
   configs += [ "//starboard/build/config:starboard_implementation" ]
 }
+
+if (build_with_separate_cobalt_toolchain) {
+  group("starboard_platform_with_main") {
+    deps = [ "//starboard/linux/x64x11:starboard_platform_with_main" ]
+  }
+}

starboard/linux/x64x11/gcc/6.3/args.gn

@@ -15,5 +15,5 @@
 target_platform = "linux-x64x11-gcc-6-3"
 target_os = "linux"
 target_cpu = "x64"
-is_clang = false
 using_old_compiler = true
+build_with_separate_cobalt_toolchain = true

starboard/linux/x64x11/gcc/6.3/cobalt/configuration.py

@@ -13,6 +13,8 @@
 # limitations under the License.
 """Starboard Linux x64x11 GCC 6.3 Cobalt configuration."""
 
+import os
+
 from starboard.linux.shared.cobalt import configuration as shared_configuration
 from starboard.tools.testing import test_filter
 
@@ -33,3 +35,8 @@ def GetTestFilters(self):
           'ZipReaderTest.ExtractToFileAsync_RegularFile',
       ],
   }
+  if os.getenv('MODULAR_BUILD', '0') == '1':
+    # TODO: b/303845477 Re-enable.
+    __FILTERED_TESTS['blackbox'] = [
+        'wasm_basic_test',
+    ]

starboard/linux/x64x11/gcc/6.3/platform_configuration/BUILD.gn

@@ -16,7 +16,11 @@ config("compiler_flags") {
   cflags = []
   cflags_c = []
   cflags_cc = []
-  ldflags = []
+
+  ldflags = [
+    # Cleanup unused sections
+    "-Wl,-gc-sections",
+  ]
 
   # from common_compiler_flags
   cflags += [
@@ -99,10 +103,15 @@ config("compiler_flags") {
 }
 
 config("platform_configuration") {
-  configs = [
-    "//starboard/linux/shared/platform_configuration",
-    "//starboard/linux/x64x11/shared/platform_configuration:libraries",
-    "//starboard/build/config/sabi",
-    ":compiler_flags",
-  ]
+  if (current_toolchain == default_toolchain &&
+      build_with_separate_cobalt_toolchain) {
+    configs = [ "//starboard/evergreen/x64/platform_configuration" ]
+  } else {
+    configs = [
+      "//starboard/linux/shared/platform_configuration",
+      "//starboard/linux/x64x11/shared/platform_configuration:libraries",
+      "//starboard/build/config/sabi",
+      ":compiler_flags",
+    ]
+  }
 }

starboard/linux/x64x11/gcc/6.3/platform_configuration/configuration.gni

@@ -12,10 +12,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import("//starboard/linux/shared/platform_configuration/configuration.gni")
+if (current_toolchain == default_toolchain &&
+    build_with_separate_cobalt_toolchain) {
+  import("//starboard/evergreen/x64/platform_configuration/configuration.gni")
+  platform_tests_path =
+      "//starboard/linux/shared:starboard_platform_tests($starboard_toolchain)"
+  cobalt_font_package = "standard"
+  sb_has_unused_symbol_issue = true
+} else {
+  import("//starboard/linux/shared/platform_configuration/configuration.gni")
 
-sabi_path = "//starboard/sabi/x64/sysv/sabi-v$sb_api_version.json"
-gl_type = "angle"
-sb_angle_enable_gl = true
+  sabi_path = "//starboard/sabi/x64/sysv/sabi-v$sb_api_version.json"
+  gl_type = "angle"
+  sb_angle_enable_gl = true
 
-sb_enable_cpp17_audit = false
+  sb_enable_cpp17_audit = false
+}

starboard/linux/x64x11/gcc/6.3/starboard_loader.cc

@@ -0,0 +1,21 @@
+// Copyright 2023 The Cobalt Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdio.h>
+#include "starboard/event.h"
+
+int main(int argc, char** argv) {
+  printf("starboard_loader: SbRunStarboardMain\n");
+  return SbRunStarboardMain(argc, argv, SbEventHandle);
+}

starboard/linux/x64x11/gcc/6.3/toolchain/BUILD.gn

@@ -12,17 +12,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import("//build/toolchain/gcc_toolchain.gni")
+import("//starboard/build/toolchain/cobalt_toolchains.gni")
 import("//starboard/shared/toolchain/overridable_gcc_toolchain.gni")
 
 # Directory for GCC 6.3 if it is installed as a system dependency.
 _default_gcc_6_3_bin_dir = "/usr/bin"
 
-overridable_gcc_toolchain("target") {
+cobalt_clang_toolchain("cobalt") {
+  native_linker_path = "${_default_gcc_6_3_bin_dir}/clang++"
+}
+
+overridable_gcc_toolchain("starboard") {
   cc = "${_default_gcc_6_3_bin_dir}/gcc-6"
   cxx = "${_default_gcc_6_3_bin_dir}/g++-6"
   ld = cxx
-
-  # We use whatever 'ar' resolves to.
   ar = "ar"
 
   toolchain_args = {