Add in basic BUILD.gn and additional DEPS

This is a minimal config that gets us building the tint binary from samples/

BUG=tint:2

Change-Id: Ifafa903e99a34f1c47177eb954df69ecbe70cb36
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/19106
Reviewed-by: dan sinclair <dsinclair@google.com>
diff --git a/.gn b/.gn
new file mode 100644
index 0000000..34c7839
--- /dev/null
+++ b/.gn
@@ -0,0 +1,21 @@
+# Copyright 2020 The Tint Authors
+#
+# 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.
+
+buildconfig = "//build/config/BUILDCONFIG.gn"
+
+check_targets = [
+  "//samples:*",
+  "//source:*",
+  "//third_party:*",
+]
diff --git a/BUILD.gn b/BUILD.gn
new file mode 100644
index 0000000..3bb1cee
--- /dev/null
+++ b/BUILD.gn
@@ -0,0 +1,219 @@
+# Copyright 2020 The Tint Authors
+#
+# 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.
+
+import("//build_overrides/build.gni")
+import("//build_overrides/tint.gni")
+
+config("tint_common_config") {
+  cflags = []
+  ldflags = []
+  include_dirs = []
+  defines = []
+}
+
+source_set("libtint") {
+  sources = [
+    "src/ast/array_accessor_expression.cc",
+    "src/ast/array_accessor_expression.h",
+    "src/ast/as_expression.cc",
+    "src/ast/as_expression.h",
+    "src/ast/assignment_statement.cc",
+    "src/ast/assignment_statement.h",
+    "src/ast/binary_expression.cc",
+    "src/ast/binary_expression.h",
+    "src/ast/binding_decoration.cc",
+    "src/ast/binding_decoration.h",
+    "src/ast/bool_literal.h",
+    "src/ast/bool_literal.cc",
+    "src/ast/break_statement.cc",
+    "src/ast/break_statement.h",
+    "src/ast/builtin.cc",
+    "src/ast/builtin.h",
+    "src/ast/builtin_decoration.cc",
+    "src/ast/builtin_decoration.h",
+    "src/ast/call_expression.cc",
+    "src/ast/call_expression.h",
+    "src/ast/case_statement.cc",
+    "src/ast/case_statement.h",
+    "src/ast/cast_expression.cc",
+    "src/ast/cast_expression.h",
+    "src/ast/constructor_expression.cc",
+    "src/ast/constructor_expression.h",
+    "src/ast/continue_statement.cc",
+    "src/ast/continue_statement.h",
+    "src/ast/decorated_variable.cc",
+    "src/ast/decorated_variable.h",
+    "src/ast/derivative_modifier.cc",
+    "src/ast/derivative_modifier.h",
+    "src/ast/else_statement.cc",
+    "src/ast/else_statement.h",
+    "src/ast/entry_point.cc",
+    "src/ast/entry_point.h",
+    "src/ast/expression.cc",
+    "src/ast/expression.h",
+    "src/ast/fallthrough_statement.cc",
+    "src/ast/fallthrough_statement.h",
+    "src/ast/float_literal.cc",
+    "src/ast/float_literal.h",
+    "src/ast/function.cc",
+    "src/ast/function.h",
+    "src/ast/identifier_expression.cc",
+    "src/ast/identifier_expression.h",
+    "src/ast/if_statement.cc",
+    "src/ast/if_statement.h",
+    "src/ast/import.cc",
+    "src/ast/import.h",
+    "src/ast/int_literal.cc",
+    "src/ast/int_literal.h",
+    "src/ast/kill_statement.cc",
+    "src/ast/kill_statement.h",
+    "src/ast/literal.h",
+    "src/ast/literal.cc",
+    "src/ast/location_decoration.cc",
+    "src/ast/location_decoration.h",
+    "src/ast/loop_statement.cc",
+    "src/ast/loop_statement.h",
+    "src/ast/member_accessor_expression.cc",
+    "src/ast/member_accessor_expression.h",
+    "src/ast/module.cc",
+    "src/ast/module.h",
+    "src/ast/node.cc",
+    "src/ast/node.h",
+    "src/ast/nop_statement.cc",
+    "src/ast/nop_statement.h",
+    "src/ast/pipeline_stage.cc",
+    "src/ast/pipeline_stage.h",
+    "src/ast/regardless_statement.cc",
+    "src/ast/regardless_statement.h",
+    "src/ast/return_statement.cc",
+    "src/ast/return_statement.h",
+    "src/ast/scalar_constructor_expression.cc",
+    "src/ast/scalar_constructor_expression.h",
+    "src/ast/set_decoration.cc",
+    "src/ast/set_decoration.h",
+    "src/ast/statement.cc",
+    "src/ast/statement.h",
+    "src/ast/statement_condition.cc",
+    "src/ast/statement_condition.h",
+    "src/ast/storage_class.cc",
+    "src/ast/storage_class.h",
+    "src/ast/struct_decoration.cc",
+    "src/ast/struct_decoration.h",
+    "src/ast/struct.cc",
+    "src/ast/struct.h",
+    "src/ast/struct_member.cc",
+    "src/ast/struct_member.h",
+    "src/ast/struct_member_decoration.cc",
+    "src/ast/struct_member_decoration.h",
+    "src/ast/struct_member_offset_decoration.cc",
+    "src/ast/struct_member_offset_decoration.h",
+    "src/ast/switch_statement.cc",
+    "src/ast/switch_statement.h",
+    "src/ast/type_constructor_expression.h",
+    "src/ast/type_constructor_expression.cc",
+    "src/ast/type/alias_type.cc",
+    "src/ast/type/alias_type.h",
+    "src/ast/type/array_type.cc",
+    "src/ast/type/array_type.h",
+    "src/ast/type/bool_type.cc",
+    "src/ast/type/bool_type.h",
+    "src/ast/type/f32_type.cc",
+    "src/ast/type/f32_type.h",
+    "src/ast/type/i32_type.cc",
+    "src/ast/type/i32_type.h",
+    "src/ast/type/matrix_type.cc",
+    "src/ast/type/matrix_type.h",
+    "src/ast/type/pointer_type.cc",
+    "src/ast/type/pointer_type.h",
+    "src/ast/type/struct_type.cc",
+    "src/ast/type/struct_type.h",
+    "src/ast/type/type.cc",
+    "src/ast/type/type.h",
+    "src/ast/type/u32_type.cc",
+    "src/ast/type/u32_type.h",
+    "src/ast/type/vector_type.cc",
+    "src/ast/type/vector_type.h",
+    "src/ast/type/void_type.cc",
+    "src/ast/type/void_type.h",
+    "src/ast/uint_literal.cc",
+    "src/ast/uint_literal.h",
+    "src/ast/unary_derivative.cc",
+    "src/ast/unary_derivative.h",
+    "src/ast/unary_derivative_expression.cc",
+    "src/ast/unary_derivative_expression.h",
+    "src/ast/unary_method.cc",
+    "src/ast/unary_method.h",
+    "src/ast/unary_method_expression.cc",
+    "src/ast/unary_method_expression.h",
+    "src/ast/unary_op.cc",
+    "src/ast/unary_op.h",
+    "src/ast/unary_op_expression.cc",
+    "src/ast/unary_op_expression.h",
+    "src/ast/unless_statement.cc",
+    "src/ast/unless_statement.h",
+    "src/ast/variable.cc",
+    "src/ast/variable.h",
+    "src/ast/variable_decoration.cc",
+    "src/ast/variable_decoration.h",
+    "src/ast/variable_decl_statement.cc",
+    "src/ast/variable_decl_statement.h",
+    "src/context.h",
+    "src/context.cc",
+    "src/reader/reader.cc",
+    "src/reader/reader.h",
+    "src/scope_stack.h",
+    "src/source.h",
+    "src/type_determiner.cc",
+    "src/type_determiner.h",
+    "src/type_manager.cc",
+    "src/type_manager.h",
+    "src/validator.cc",
+    "src/validator.h",
+    "src/validator_impl.cc",
+    "src/validator_impl.h",
+    "src/writer/writer.cc",
+    "src/writer/writer.h",
+  ]
+
+  if (build_with_chromium) {
+    configs -= [ "//build/config/compiler:chromium_code" ]
+    configs += [ "//build/config/compiler:no_chromium_code" ]
+  }
+
+  # Suppress warnings from the Chromium Clang plugin
+  configs -= [ "//build/config/clang:find_bad_constructs" ]
+}
+
+executable("tint") {
+  sources = [
+    "samples/main.cc",
+  ]
+  deps = [
+    ":libtint",
+  ]
+
+  if (build_with_chromium) {
+    configs -= [ "//build/config/compiler:chromium_code" ]
+    configs += [ "//build/config/compiler:no_chromium_code" ]
+  }
+
+  # Suppress warnings from the Chromium Clang plugin
+  configs -= [ "//build/config/clang:find_bad_constructs" ]
+}
+
+group("tint_all") {
+  deps = [
+      ":tint",
+    ]
+}
diff --git a/DEPS b/DEPS
index 26c5480..8cad279 100644
--- a/DEPS
+++ b/DEPS
@@ -4,6 +4,10 @@
   'chromium_git':  'https://chromium.googlesource.com',
   'github': '/external/github.com',
 
+  'binutils_revision': '01aa7745b0bab64ae22600f09fd6483c60f22ebf',
+  'build_revision': 'f3d0ca5f46b7b190dbbdc6be508ca11dd5c54302',
+  'buildtools_revision': '74cfb57006f83cfe050817526db359d5c8a11628',
+  'clang_revision': '3605577b67603ec5776afcfada9e0ff4ea05cf0e',
   'cpplint_revision': '305ac8725a166ed42e3f5dd3f80d6de2cf840ef1',
   'googletest_revision': '482ac6ee63429af2aa9c44f4e6427873fb68fb1f',
   'spirv_headers_revision': 'f8bf11a0253a32375c32cad92c841237b96696c0',
@@ -22,4 +26,120 @@
 
   'third_party/spirv-tools': Var('chromium_git') + Var('github') +
       '/KhronosGroup//SPIRV-Tools.git@' + Var('spirv_tools_revision'),
+
+  # Dependencies required to use GN/Clang in standalone
+  'build': Var('chromium_git') + '/chromium/src/build@' +
+      Var('build_revision'),
+
+  'buildtools': Var('chromium_git') + '/chromium/src/buildtools@' +
+      Var('buildtools_revision'),
+
+  'tools/clang': Var('chromium_git') + '/chromium/src/tools/clang@' +
+      Var('clang_revision'),
+
+  'third_party/binutils': Var('chromium_git') +
+      '/chromium/src/third_party/binutils@' + Var('binutils_revision'),
 }
+
+hooks = [
+  # Pull clang-format binaries using checked-in hashes.
+  {
+    'name': 'clang_format_win',
+    'pattern': '.',
+    'condition': 'host_os == "win"',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=win32',
+                '--no_auth',
+                '--bucket', 'chromium-clang-format',
+                '-s', 'buildtools/win/clang-format.exe.sha1',
+    ],
+  },
+  {
+    'name': 'clang_format_mac',
+    'pattern': '.',
+    'condition': 'host_os == "mac"',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=darwin',
+                '--no_auth',
+                '--bucket', 'chromium-clang-format',
+                '-s', 'buildtools/mac/clang-format.sha1',
+    ],
+  },
+  {
+    'name': 'clang_format_linux',
+    'pattern': '.',
+    'condition': 'host_os == "linux"',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=linux*',
+                '--no_auth',
+                '--bucket', 'chromium-clang-format',
+                '-s', 'buildtools/linux64/clang-format.sha1',
+    ],
+  },
+
+  # Pull the compilers and system libraries for hermetic builds
+  {
+    'name': 'sysroot_x86',
+    'pattern': '.',
+    'condition': 'checkout_linux and ((checkout_x86 or checkout_x64))',
+    'action': ['python', 'build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=x86'],
+  },
+  {
+    'name': 'sysroot_x64',
+    'pattern': '.',
+    'condition': 'checkout_linux and (checkout_x64)',
+    'action': ['python', 'build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=x64'],
+  },
+  {
+    # Update the Windows toolchain if necessary. Must run before 'clang' below.
+    'name': 'win_toolchain',
+    'pattern': '.',
+    'condition': 'checkout_win',
+    'action': ['python', 'build/vs_toolchain.py', 'update', '--force'],
+  },
+  {
+    # Note: On Win, this should run after win_toolchain, as it may use it.
+    'name': 'clang',
+    'pattern': '.',
+    'action': ['python', 'tools/clang/scripts/update.py'],
+  },
+  {
+    # Pull rc binaries using checked-in hashes.
+    'name': 'rc_win',
+    'pattern': '.',
+    'condition': 'checkout_win and (host_os == "win")',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--no_auth',
+                '--bucket', 'chromium-browser-clang/rc',
+                '-s', 'build/toolchain/win/rc/win/rc.exe.sha1',
+    ],
+  },
+  # Pull binutils for linux hermetic builds
+  {
+    'name': 'binutils',
+    'pattern': 'src/third_party/binutils',
+    'condition': 'host_os == "linux"',
+    'action': [
+        'python',
+        'third_party/binutils/download.py',
+    ],
+  },
+  # Update build/util/LASTCHANGE.
+  {
+    'name': 'lastchange',
+    'pattern': '.',
+    'action': ['python', 'build/util/lastchange.py',
+               '-o', 'build/util/LASTCHANGE'],
+  },
+]
+
+recursedeps = [
+  # buildtools provides clang_format, libc++, and libc++abi
+  'buildtools',
+]
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
new file mode 100644
index 0000000..3e06b7b
--- /dev/null
+++ b/build_overrides/build.gni
@@ -0,0 +1,48 @@
+# Copyright 2020 The Tint Authors.
+#
+# 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.
+
+# This file contains build-related overrides.
+
+# Variable that can be used to support multiple build scenarios, like having
+# Chromium specific targets in a client project's GN file etc.
+build_with_chromium = false
+
+# Builds don't use Chromium's third_party/binutils.
+linux_use_bundled_binutils_override = false
+
+declare_args() {
+  # Android 32-bit non-component, non-clang builds cannot have symbol_level=2
+  # due to 4GiB file size limit, see https://crbug.com/648948.
+  # Set this flag to true to skip the assertion.
+  ignore_elf32_limitations = false
+
+  # Use the system install of Xcode for tools like ibtool, libtool, etc.
+  # This does not affect the compiler. When this variable is false, targets will
+  # instead use a hermetic install of Xcode. [The hermetic install can be
+  # obtained with gclient sync after setting the environment variable
+  # FORCE_MAC_TOOLCHAIN].
+  use_system_xcode = ""
+}
+
+if (use_system_xcode == "") {
+  if (target_os == "mac") {
+    _result = exec_script("//build/mac/should_use_hermetic_xcode.py",
+                          [ target_os ],
+                          "value")
+    use_system_xcode = _result == 0
+  }
+  if (target_os == "ios") {
+    use_system_xcode = true
+  }
+}
diff --git a/build_overrides/tint.gni b/build_overrides/tint.gni
new file mode 100644
index 0000000..fdcc866
--- /dev/null
+++ b/build_overrides/tint.gni
@@ -0,0 +1,15 @@
+# Copyright 2020 The Tint Authors.
+#
+# 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.
+
+# This file contains Tint-related overrides.
diff --git a/tint.gni b/tint.gni
new file mode 100644
index 0000000..8986907
--- /dev/null
+++ b/tint.gni
@@ -0,0 +1,43 @@
+# Copyright 2020 The Tint Authors.
+#
+# 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.
+
+import("//build_overrides/tint.gni")
+
+# This file contains Tint-related build flags.
+
+declare_args() {
+  # Generate documentation
+  # TODO(rharrison): Implement documentation support
+  tint_build_doc = false
+
+  # Generate SPIR-V input parser
+  # TODO(rharrison): Implement SPIR-V input parser support
+  tint_build_spv_parser = false
+
+  # Generate fuzzers
+  # TODO(rharrison): Implement fuzzer support
+  tint_build_fuzzers = false
+
+  # Enable memory sanitizer
+  # TODO(rharrison): Implement sanitizer support
+  tint_enable_msan = false
+
+  # Enable address sanitizer
+  # TODO(rharrison): Implement sanitizer support
+  tint_enable_msan = false
+
+  # Enable undefined behaviour sanitizer
+  # TODO(rharrison): Implement sanitizer support
+  tint_enable_ubsan = false
+}
\ No newline at end of file