Migrate build_overrides from buildroot to engine

Files under the build_overrides directory in the buildroot are typically hardcoded imports in third-party dependencies used for project-specific configuration. For example, ANGLE hardcodes an import of `//build_overrides/angle.gni` so that consumers of ANGLE can configure the build to their needs. This adds a copy all existing src/build_overrides files at the equivalent `src/flutter/build_overrides` path in the engine. A followup patch will replace each existing file under `src/build_overrides` in the buildroot with a shim that just imports the files landed in this patch. This allows the upstream project to continue hardcoding the `//build_overrides/foo.gni` path, but provides a seamless path forward when we drop the buildroot. Adds flutter/build_overrides as an excluded path for the licence script. Issue: flutter/flutter#144790 Part of: flutter/flutter#67373
flutter · auto-submit · Mar 7, 2024 · Mar 7, 2024 · Mar 7, 2024 · Mar 7, 2024
commit 5fa9f0805987b999ed53526dd0d20852d14d40b8
diff --git a/build_overrides/angle.gni b/build_overrides/angle.gni
@@ -0,0 +1,38 @@
+# Copyright 2019 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Ensure use_xcode_clang is visibile to ANGLE.
+import("//build/toolchain/toolchain.gni")
+
+# The ANGLE build requires this file to point to the location of third-party
+# dependencies.
+angle_root = "//third_party/angle"
+
+angle_vma_version = 30000001
+
+# Flutter's buildroot looks enough like Chromium to satisfy Angle, and enough
+# to cause GN variable collisions if we don't set this.
+if (!is_fuchsia) {
+  angle_has_build = true
+}
+
+# Overrides for ANGLE's dependencies.
+angle_abseil_cpp_dir = "//flutter/third_party/abseil-cpp"
+angle_glslang_dir = "//flutter/third_party/vulkan-deps/glslang/src"
+angle_googletest_dir = "//third_party/googletest/googletest/src"
+
+# Note: This path doesn't actually exist; see
+# //build/secondary/third_party/jsoncpp/BUILD.gn
+angle_jsoncpp_dir = "//third_party/jsoncpp"
+angle_libjpeg_turbo_dir = "//third_party/libjpeg_turbo"
+angle_libpng_dir = "//flutter/third_party/libpng"
+angle_spirv_headers_dir = "//flutter/third_party/vulkan-deps/spirv-headers/src"
+angle_spirv_tools_dir = "//flutter/third_party/vulkan-deps/spirv-tools/src"
+angle_spirv_cross_dir = "//flutter/third_party/vulkan-deps/spirv-cross/src"
+angle_spirv_headers_dir = "//flutter/third_party/vulkan-deps/spirv-headers/src"
+angle_vulkan_memory_allocator_dir = "//third_party/vulkan_memory_allocator"
+
+# This is a general Chromium flag, but in the Flutter build only ANGLE needs it
+# so it is defined here.
+is_cfi = false
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
@@ -0,0 +1,13 @@
+# Copyright 2019 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# The engine build uses some Chromium-sourced versions of third-party
+# dependencies (e.g, ANGLE, abseil) to use their GN build files, but we don't
+# want the Chromium-specific parts of the build.
+build_with_chromium = false
+
+# Perfetto targets fail to build without this variable. It is used by Perfetto
+# targets to distinguish embedder builds from Perfetto standalone builds, and
+# builds in the Android tree.
+perfetto_build_with_embedder = true
diff --git a/build_overrides/glslang.gni b/build_overrides/glslang.gni
@@ -0,0 +1,6 @@
+# Copyright 2019 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+glslang_spirv_tools_dir = "//flutter/third_party/vulkan-deps/spirv-tools/src"
+spirv_tools_dir = "//flutter/third_party/vulkan-deps/spirv-tools/src"
diff --git a/build_overrides/spirv_tools.gni b/build_overrides/spirv_tools.gni
@@ -0,0 +1,11 @@
+# Copyright 2019 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# We are building inside Flutter.
+spirv_tools_standalone = false
+
+# Paths to SPIRV-Tools dependencies in Flutter.
+spirv_tools_googletest_dir = "//third_party/googletest/googletest/src"
+spirv_tools_spirv_headers_dir =
+    "//flutter/third_party/vulkan-deps/spirv-headers/src"
diff --git a/build_overrides/swiftshader.gni b/build_overrides/swiftshader.gni
@@ -0,0 +1,9 @@
+# Copyright 2019 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# We are building SwiftShader in Flutter.
+swiftshader_standalone = false
+
+# Path to SwiftShader.
+swiftshader_dir = "//flutter/third_party/swiftshader"
diff --git a/build_overrides/vulkan_headers.gni b/build_overrides/vulkan_headers.gni
@@ -0,0 +1,11 @@
+# Copyright 2020 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This file is needed by the vulkan-headers build, but doesn't need to actually
+# set anything.
+
+if (is_linux) {
+  vulkan_use_x11 = true
+  vulkan_use_wayland = true
+}
diff --git a/build_overrides/vulkan_loader.gni b/build_overrides/vulkan_loader.gni
@@ -0,0 +1,8 @@
+# Copyright 2020 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+vulkan_headers_dir = "//flutter/third_party/vulkan-deps/vulkan-headers/src"
+
+# Vulkan loader build options
+vulkan_loader_shared = true
diff --git a/build_overrides/vulkan_tools.gni b/build_overrides/vulkan_tools.gni
@@ -0,0 +1,9 @@
+# Copyright 2020 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+vulkan_headers_dir = "//flutter/third_party/vulkan-deps/vulkan-headers/src"
+
+# Subdirectories for generated files
+vulkan_data_subdir = ""
+vulkan_gen_subdir = ""
diff --git a/build_overrides/vulkan_utility_libraries.gni b/build_overrides/vulkan_utility_libraries.gni
@@ -0,0 +1,5 @@
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+vulkan_headers_dir = "//flutter/third_party/vulkan-deps/vulkan-headers/src"
diff --git a/build_overrides/vulkan_validation_layers.gni b/build_overrides/vulkan_validation_layers.gni
@@ -0,0 +1,15 @@
+# Copyright 2020 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+vulkan_headers_dir = "//flutter/third_party/vulkan-deps/vulkan-headers/src"
+vulkan_utility_libraries_dir =
+    "//flutter/third_party/vulkan-deps/vulkan-utility-libraries/src"
+vvl_spirv_tools_dir = "//flutter/third_party/vulkan-deps/spirv-tools/src"
+vvl_glslang_dir = "//flutter/third_party/vulkan-deps/spirv-tools/src"
+
+# robin_hood_headers_dir = "//external/robin-hood-hashing/src/include"
+
+# Subdirectories for generated files
+vulkan_data_subdir = "vulkan-data"
+vulkan_gen_subdir = ""
diff --git a/build_overrides/wayland.gni b/build_overrides/wayland.gni
@@ -0,0 +1,8 @@
+# Copyright 2019 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# ANGLE expects this to be here.
+
+# Flutter has no wayland third-party dir
+wayland_gn_dir = ""
diff --git a/tools/licenses/lib/paths.dart b/tools/licenses/lib/paths.dart
@@ -21,6 +21,7 @@ final Set<String> skippedPaths = <String>{
   r'build_overrides', // only used by build
   r'buildtools', // only used by build
   r'flutter/build',
+  r'flutter/build_overrides', // only used by build
   r'flutter/ci',
   r'flutter/docs',
   r'flutter/flutter_frontend_server',