diff --git a/.gitignore b/.gitignore
index aa12fcc8..a78c04df 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,14 +1,17 @@
 .clang_complete
 .ycm_extra_conf.py*
 compile_commands.json
-/build*
+/build/
+/buildtools/
 /external/googletest
 /external/SPIRV-Headers
 /external/spirv-headers
 /external/effcee
 /external/re2
+/out
 /TAGS
 /third_party/llvm-build/
+/testing/libfuzzer/
 /tools/clang/
 /utils/clang-format-diff.py
 
diff --git a/.gn b/.gn
new file mode 100644
index 00000000..ee4734f7
--- /dev/null
+++ b/.gn
@@ -0,0 +1,20 @@
+# Copyright 2018 Google Inc.
+#
+# 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
+#
+#     https://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"
+secondary_source = "//build/secondary/"
+
+default_args = {
+  use_custom_libcxx = false
+}
diff --git a/BUILD.gn b/BUILD.gn
new file mode 100644
index 00000000..9765a889
--- /dev/null
+++ b/BUILD.gn
@@ -0,0 +1,776 @@
+# Copyright 2018 Google Inc. 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.
+
+import("//testing/test.gni")
+import("//build_overrides/build.gni")
+
+if (build_with_chromium) {
+  spirv_headers = "//third_party/spirv-headers/src"
+} else {
+  spirv_headers = "external/spirv-headers"
+}
+
+template("spvtools_core_tables") {
+  assert(defined(invoker.version), "Need version in $target_name generation.")
+
+  action("spvtools_core_tables_" + target_name) {
+    script = "utils/generate_grammar_tables.py"
+
+    version = invoker.version
+
+    core_json_file =
+        "${spirv_headers}/include/spirv/$version/spirv.core.grammar.json"
+    core_insts_file = "${target_gen_dir}/core.insts-$version.inc"
+    operand_kinds_file = "${target_gen_dir}/operand.kinds-$version.inc"
+    extinst_file = "source/extinst.debuginfo.grammar.json"
+
+    sources = [
+      core_json_file,
+    ]
+    outputs = [
+      core_insts_file,
+      operand_kinds_file,
+    ]
+    args = [
+      "--spirv-core-grammar",
+      rebase_path(core_json_file, root_build_dir),
+      "--core-insts-output",
+      rebase_path(core_insts_file, root_build_dir),
+      "--extinst-debuginfo-grammar",
+      rebase_path(extinst_file, root_build_dir),
+      "--operand-kinds-output",
+      rebase_path(operand_kinds_file, root_build_dir),
+    ]
+  }
+}
+
+template("spvtools_core_enums") {
+  assert(defined(invoker.version), "Need version in $target_name generation.")
+
+  action("spvtools_core_enums_" + target_name) {
+    script = "utils/generate_grammar_tables.py"
+
+    version = invoker.version
+
+    core_json_file =
+        "${spirv_headers}/include/spirv/$version/spirv.core.grammar.json"
+    debug_insts_file = "source/extinst.debuginfo.grammar.json"
+    extension_enum_file = "${target_gen_dir}/extension_enum.inc"
+    extension_map_file = "${target_gen_dir}/enum_string_mapping.inc"
+
+    args = [
+      "--spirv-core-grammar",
+      rebase_path(core_json_file, root_build_dir),
+      "--extinst-debuginfo-grammar",
+      rebase_path(debug_insts_file, root_build_dir),
+      "--extension-enum-output",
+      rebase_path(extension_enum_file, root_build_dir),
+      "--enum-string-mapping-output",
+      rebase_path(extension_map_file, root_build_dir),
+    ]
+    inputs = [
+      core_json_file,
+    ]
+    outputs = [
+      extension_enum_file,
+      extension_map_file,
+    ]
+  }
+}
+
+template("spvtools_glsl_tables") {
+  assert(defined(invoker.version), "Need version in $target_name generation.")
+
+  action("spvtools_glsl_tables_" + target_name) {
+    script = "utils/generate_grammar_tables.py"
+
+    version = invoker.version
+
+    core_json_file =
+        "${spirv_headers}/include/spirv/$version/spirv.core.grammar.json"
+    glsl_json_file = "${spirv_headers}/include/spirv/${version}/extinst.glsl.std.450.grammar.json"
+    glsl_insts_file = "${target_gen_dir}/glsl.std.450.insts.inc"
+    debug_insts_file = "source/extinst.debuginfo.grammar.json"
+
+    args = [
+      "--spirv-core-grammar",
+      rebase_path(core_json_file, root_build_dir),
+      "--extinst-glsl-grammar",
+      rebase_path(glsl_json_file, root_build_dir),
+      "--glsl-insts-output",
+      rebase_path(glsl_insts_file, root_build_dir),
+      "--extinst-debuginfo-grammar",
+      rebase_path(debug_insts_file, root_build_dir),
+    ]
+    inputs = [
+      core_json_file,
+      glsl_json_file,
+    ]
+    outputs = [
+      glsl_insts_file,
+    ]
+  }
+}
+
+template("spvtools_opencl_tables") {
+  assert(defined(invoker.version), "Need version in $target_name generation.")
+
+  action("spvtools_opencl_tables_" + target_name) {
+    script = "utils/generate_grammar_tables.py"
+
+    version = invoker.version
+
+    core_json_file =
+        "${spirv_headers}/include/spirv/$version/spirv.core.grammar.json"
+    opengl_json_file = "${spirv_headers}/include/spirv/${version}/extinst.opencl.std.100.grammar.json"
+    opencl_insts_file = "${target_gen_dir}/opencl.std.insts.inc"
+    debug_insts_file = "source/extinst.debuginfo.grammar.json"
+
+    args = [
+      "--spirv-core-grammar",
+      rebase_path(core_json_file, root_build_dir),
+      "--extinst-opencl-grammar",
+      rebase_path(opengl_json_file, root_build_dir),
+      "--opencl-insts-output",
+      rebase_path(opencl_insts_file, root_build_dir),
+      "--extinst-debuginfo-grammar",
+      rebase_path(debug_insts_file, root_build_dir),
+    ]
+    inputs = [
+      core_json_file,
+      opengl_json_file,
+    ]
+    outputs = [
+      opencl_insts_file,
+    ]
+  }
+}
+
+template("spvtools_language_header") {
+  assert(defined(invoker.name), "Need name in $target_name generation.")
+
+  action("spvtools_language_header_" + target_name) {
+    script = "utils/generate_language_headers.py"
+
+    name = invoker.name
+    extinst_output_base = "${target_gen_dir}/${name}"
+    debug_insts_file = "source/extinst.debuginfo.grammar.json"
+
+    args = [
+      "--extinst-name",
+      "${name}",
+      "--extinst-grammar",
+      rebase_path(debug_insts_file, root_build_dir),
+      "--extinst-output-base",
+      rebase_path(extinst_output_base, root_build_dir),
+    ]
+    inputs = [
+      debug_insts_file,
+    ]
+    outputs = [
+      "${extinst_output_base}.h",
+    ]
+  }
+}
+
+template("spvtools_vendor_table") {
+  assert(defined(invoker.name), "Need name in $target_name generation.")
+
+  action("spvtools_vendor_tables_" + target_name) {
+    script = "utils/generate_grammar_tables.py"
+
+    name = invoker.name
+    extinst_vendor_grammar = "source/extinst.${name}.grammar.json"
+    extinst_file = "${target_gen_dir}/${name}.insts.inc"
+
+    args = [
+      "--extinst-vendor-grammar",
+      rebase_path(extinst_vendor_grammar, root_build_dir),
+      "--vendor-insts-output",
+      rebase_path(extinst_file, root_build_dir),
+    ]
+    inputs = [
+      extinst_vendor_grammar,
+    ]
+    outputs = [
+      extinst_file,
+    ]
+  }
+}
+
+action("spvtools_generators_inc") {
+  script = "utils/generate_registry_tables.py"
+
+  # TODO(dsinclair): Make work for chrome
+  xml_file = "${spirv_headers}/include/spirv/spir-v.xml"
+  inc_file = "${target_gen_dir}/generators.inc"
+
+  sources = [
+    xml_file,
+  ]
+  outputs = [
+    inc_file,
+  ]
+  args = [
+    "--xml",
+    rebase_path(xml_file, root_build_dir),
+    "--generator",
+    rebase_path(inc_file, root_build_dir),
+  ]
+}
+
+spvtools_core_tables("unified1") {
+  version = "unified1"
+}
+spvtools_core_enums("unified1") {
+  version = "unified1"
+}
+spvtools_glsl_tables("glsl1-0") {
+  version = "1.0"
+}
+spvtools_opencl_tables("opencl1-0") {
+  version = "1.0"
+}
+spvtools_language_header("unified1") {
+  name = "DebugInfo"
+}
+
+spvtools_vendor_tables = [
+  "spv-amd-shader-explicit-vertex-parameter",
+  "spv-amd-shader-trinary-minmax",
+  "spv-amd-gcn-shader",
+  "spv-amd-shader-ballot",
+  "debuginfo",
+]
+
+foreach(table, spvtools_vendor_tables) {
+  spvtools_vendor_table(table) {
+    name = table
+  }
+}
+
+config("spvtools_config") {
+  include_dirs = [
+    ".",
+    "include",
+    "source",
+    "$target_gen_dir",
+    "${spirv_headers}/include",
+  ]
+
+  if (is_clang) {
+    cflags = [ "-Wno-implicit-fallthrough" ]
+  }
+}
+
+static_library("spvtools") {
+  deps = [
+    ":spvtools_core_enums_unified1",
+    ":spvtools_core_tables_unified1",
+    ":spvtools_generators_inc",
+    ":spvtools_glsl_tables_glsl1-0",
+    ":spvtools_language_header_unified1",
+    ":spvtools_opencl_tables_opencl1-0",
+  ]
+  foreach(target_name, spvtools_vendor_tables) {
+    deps += [ ":spvtools_vendor_tables_$target_name" ]
+  }
+
+  sources = [
+    "source/assembly_grammar.cpp",
+    "source/assembly_grammar.h",
+    "source/binary.cpp",
+    "source/binary.h",
+    "source/diagnostic.cpp",
+    "source/diagnostic.h",
+    "source/disassemble.cpp",
+    "source/enum_set.h",
+    "source/enum_string_mapping.cpp",
+    "source/ext_inst.cpp",
+    "source/ext_inst.h",
+    "source/extensions.cpp",
+    "source/extensions.h",
+    "source/instruction.h",
+    "source/libspirv.cpp",
+    "source/macro.h",
+    "source/message.cpp",
+    "source/name_mapper.cpp",
+    "source/name_mapper.h",
+    "source/opcode.cpp",
+    "source/opcode.h",
+    "source/operand.cpp",
+    "source/operand.h",
+    "source/parsed_operand.cpp",
+    "source/parsed_operand.h",
+    "source/print.cpp",
+    "source/print.h",
+    "source/spirv_constant.h",
+    "source/spirv_definition.h",
+    "source/spirv_endian.cpp",
+    "source/spirv_endian.h",
+    "source/spirv_target_env.cpp",
+    "source/spirv_target_env.h",
+    "source/spirv_validator_options.cpp",
+    "source/spirv_validator_options.h",
+    "source/table.cpp",
+    "source/table.h",
+    "source/text.cpp",
+    "source/text.h",
+    "source/text_handler.cpp",
+    "source/text_handler.h",
+    "source/util/bit_stream.cpp",
+    "source/util/bit_stream.h",
+    "source/util/bit_vector.cpp",
+    "source/util/bit_vector.h",
+    "source/util/bitutils.h",
+    "source/util/hex_float.h",
+    "source/util/hufman_codec.h",
+    "source/util/ilist.h",
+    "source/util/ilist_node.h",
+    "source/util/move_to_front.h",
+    "source/util/parse_number.cpp",
+    "source/util/parse_number.h",
+    "source/util/small_vector.h",
+    "source/util/string_utils.cpp",
+    "source/util/string_utils.h",
+    "source/util/timer.cpp",
+    "source/util/timer.h",
+  ]
+
+  public_configs = [ ":spvtools_config" ]
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
+}
+
+static_library("spvtools_val") {
+  sources = [
+    "source/val/basic_block.cpp",
+    "source/val/construct.cpp",
+    "source/val/function.cpp",
+    "source/val/instruction.cpp",
+    "source/val/validate.cpp",
+    "source/val/validate.h",
+    "source/val/validate_adjacency.cpp",
+    "source/val/validate_arithmetics.cpp",
+    "source/val/validate_atomics.cpp",
+    "source/val/validate_barriers.cpp",
+    "source/val/validate_bitwise.cpp",
+    "source/val/validate_builtins.cpp",
+    "source/val/validate_capability.cpp",
+    "source/val/validate_cfg.cpp",
+    "source/val/validate_composites.cpp",
+    "source/val/validate_conversion.cpp",
+    "source/val/validate_datarules.cpp",
+    "source/val/validate_decorations.cpp",
+    "source/val/validate_derivatives.cpp",
+    "source/val/validate_ext_inst.cpp",
+    "source/val/validate_id.cpp",
+    "source/val/validate_image.cpp",
+    "source/val/validate_instruction.cpp",
+    "source/val/validate_interfaces.cpp",
+    "source/val/validate_layout.cpp",
+    "source/val/validate_literals.cpp",
+    "source/val/validate_logicals.cpp",
+    "source/val/validate_non_uniform.cpp",
+    "source/val/validate_primitives.cpp",
+    "source/val/validate_type_unique.cpp",
+    "source/val/validation_state.cpp",
+  ]
+
+  deps = [
+    ":spvtools",
+  ]
+
+  public_configs = [ ":spvtools_config" ]
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
+}
+
+static_library("spvtools_opt") {
+  sources = [
+    "source/opt/aggressive_dead_code_elim_pass.cpp",
+    "source/opt/aggressive_dead_code_elim_pass.h",
+    "source/opt/basic_block.cpp",
+    "source/opt/basic_block.h",
+    "source/opt/block_merge_pass.cpp",
+    "source/opt/block_merge_pass.h",
+    "source/opt/build_module.cpp",
+    "source/opt/build_module.h",
+    "source/opt/ccp_pass.cpp",
+    "source/opt/ccp_pass.h",
+    "source/opt/cfg.cpp",
+    "source/opt/cfg.h",
+    "source/opt/cfg_cleanup_pass.cpp",
+    "source/opt/cfg_cleanup_pass.h",
+    "source/opt/common_uniform_elim_pass.cpp",
+    "source/opt/common_uniform_elim_pass.h",
+    "source/opt/compact_ids_pass.cpp",
+    "source/opt/compact_ids_pass.h",
+    "source/opt/composite.cpp",
+    "source/opt/composite.h",
+    "source/opt/const_folding_rules.cpp",
+    "source/opt/const_folding_rules.h",
+    "source/opt/constants.cpp",
+    "source/opt/constants.h",
+    "source/opt/copy_prop_arrays.cpp",
+    "source/opt/copy_prop_arrays.h",
+    "source/opt/dead_branch_elim_pass.cpp",
+    "source/opt/dead_branch_elim_pass.h",
+    "source/opt/dead_insert_elim_pass.cpp",
+    "source/opt/dead_insert_elim_pass.h",
+    "source/opt/dead_variable_elimination.cpp",
+    "source/opt/dead_variable_elimination.h",
+    "source/opt/decoration_manager.cpp",
+    "source/opt/decoration_manager.h",
+    "source/opt/def_use_manager.cpp",
+    "source/opt/def_use_manager.h",
+    "source/opt/dominator_analysis.cpp",
+    "source/opt/dominator_analysis.h",
+    "source/opt/dominator_tree.cpp",
+    "source/opt/dominator_tree.h",
+    "source/opt/eliminate_dead_constant_pass.cpp",
+    "source/opt/eliminate_dead_constant_pass.h",
+    "source/opt/eliminate_dead_functions_pass.cpp",
+    "source/opt/eliminate_dead_functions_pass.h",
+    "source/opt/feature_manager.cpp",
+    "source/opt/feature_manager.h",
+    "source/opt/flatten_decoration_pass.cpp",
+    "source/opt/flatten_decoration_pass.h",
+    "source/opt/fold.cpp",
+    "source/opt/fold.h",
+    "source/opt/fold_spec_constant_op_and_composite_pass.cpp",
+    "source/opt/fold_spec_constant_op_and_composite_pass.h",
+    "source/opt/folding_rules.cpp",
+    "source/opt/folding_rules.h",
+    "source/opt/freeze_spec_constant_value_pass.cpp",
+    "source/opt/freeze_spec_constant_value_pass.h",
+    "source/opt/function.cpp",
+    "source/opt/function.h",
+    "source/opt/if_conversion.cpp",
+    "source/opt/if_conversion.h",
+    "source/opt/inline_exhaustive_pass.cpp",
+    "source/opt/inline_exhaustive_pass.h",
+    "source/opt/inline_opaque_pass.cpp",
+    "source/opt/inline_opaque_pass.h",
+    "source/opt/inline_pass.cpp",
+    "source/opt/inline_pass.h",
+    "source/opt/instruction.cpp",
+    "source/opt/instruction.h",
+    "source/opt/instruction_list.cpp",
+    "source/opt/instruction_list.h",
+    "source/opt/ir_builder.h",
+    "source/opt/ir_context.cpp",
+    "source/opt/ir_context.h",
+    "source/opt/ir_loader.cpp",
+    "source/opt/ir_loader.h",
+    "source/opt/iterator.h",
+    "source/opt/licm_pass.cpp",
+    "source/opt/licm_pass.h",
+    "source/opt/local_access_chain_convert_pass.cpp",
+    "source/opt/local_access_chain_convert_pass.h",
+    "source/opt/local_redundancy_elimination.cpp",
+    "source/opt/local_redundancy_elimination.h",
+    "source/opt/local_single_block_elim_pass.cpp",
+    "source/opt/local_single_block_elim_pass.h",
+    "source/opt/local_single_store_elim_pass.cpp",
+    "source/opt/local_single_store_elim_pass.h",
+    "source/opt/local_ssa_elim_pass.cpp",
+    "source/opt/local_ssa_elim_pass.h",
+    "source/opt/log.h",
+    "source/opt/loop_dependence.cpp",
+    "source/opt/loop_dependence.h",
+    "source/opt/loop_dependence_helpers.cpp",
+    "source/opt/loop_descriptor.cpp",
+    "source/opt/loop_descriptor.h",
+    "source/opt/loop_fission.cpp",
+    "source/opt/loop_fission.h",
+    "source/opt/loop_fusion.cpp",
+    "source/opt/loop_fusion.h",
+    "source/opt/loop_fusion_pass.cpp",
+    "source/opt/loop_fusion_pass.h",
+    "source/opt/loop_peeling.cpp",
+    "source/opt/loop_peeling.h",
+    "source/opt/loop_unroller.cpp",
+    "source/opt/loop_unroller.h",
+    "source/opt/loop_unswitch_pass.cpp",
+    "source/opt/loop_unswitch_pass.h",
+    "source/opt/loop_utils.cpp",
+    "source/opt/loop_utils.h",
+    "source/opt/make_unique.h",
+    "source/opt/mem_pass.cpp",
+    "source/opt/mem_pass.h",
+    "source/opt/merge_return_pass.cpp",
+    "source/opt/merge_return_pass.h",
+    "source/opt/module.cpp",
+    "source/opt/module.h",
+    "source/opt/null_pass.h",
+    "source/opt/optimizer.cpp",
+    "source/opt/pass.cpp",
+    "source/opt/pass.h",
+    "source/opt/pass_manager.cpp",
+    "source/opt/pass_manager.h",
+    "source/opt/passes.h",
+    "source/opt/private_to_local_pass.cpp",
+    "source/opt/private_to_local_pass.h",
+    "source/opt/propagator.cpp",
+    "source/opt/propagator.h",
+    "source/opt/reduce_load_size.cpp",
+    "source/opt/reduce_load_size.h",
+    "source/opt/redundancy_elimination.cpp",
+    "source/opt/redundancy_elimination.h",
+    "source/opt/reflect.h",
+    "source/opt/register_pressure.cpp",
+    "source/opt/register_pressure.h",
+    "source/opt/remove_duplicates_pass.cpp",
+    "source/opt/remove_duplicates_pass.h",
+    "source/opt/replace_invalid_opc.cpp",
+    "source/opt/replace_invalid_opc.h",
+    "source/opt/scalar_analysis.cpp",
+    "source/opt/scalar_analysis.h",
+    "source/opt/scalar_analysis_nodes.h",
+    "source/opt/scalar_analysis_simplification.cpp",
+    "source/opt/scalar_replacement_pass.cpp",
+    "source/opt/scalar_replacement_pass.h",
+    "source/opt/set_spec_constant_default_value_pass.cpp",
+    "source/opt/set_spec_constant_default_value_pass.h",
+    "source/opt/simplification_pass.cpp",
+    "source/opt/simplification_pass.h",
+    "source/opt/ssa_rewrite_pass.cpp",
+    "source/opt/ssa_rewrite_pass.h",
+    "source/opt/strength_reduction_pass.cpp",
+    "source/opt/strength_reduction_pass.h",
+    "source/opt/strip_debug_info_pass.cpp",
+    "source/opt/strip_debug_info_pass.h",
+    "source/opt/strip_reflect_info_pass.cpp",
+    "source/opt/strip_reflect_info_pass.h",
+    "source/opt/tree_iterator.h",
+    "source/opt/type_manager.cpp",
+    "source/opt/type_manager.h",
+    "source/opt/types.cpp",
+    "source/opt/types.h",
+    "source/opt/unify_const_pass.cpp",
+    "source/opt/unify_const_pass.h",
+    "source/opt/value_number_table.cpp",
+    "source/opt/value_number_table.h",
+    "source/opt/vector_dce.cpp",
+    "source/opt/vector_dce.h",
+    "source/opt/workaround1209.cpp",
+    "source/opt/workaround1209.h",
+  ]
+  deps = [
+    ":spvtools",
+  ]
+
+  public_configs = [ ":spvtools_config" ]
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
+}
+
+static_library("SPIRV-Tools") {
+  deps = [
+    ":spvtools",
+    ":spvtools_opt",
+    ":spvtools_val",
+  ]
+}
+
+if (!build_with_chromium) {
+  static_library("gtest") {
+    testonly = true
+
+    defines = [
+      # In order to allow regex matches in gtest to be shared between Windows
+      # and other systems, we tell gtest to always use its internal engine.
+      "GTEST_HAS_POSIX_RE=0",
+
+      # Enables C++11 features.
+      "GTEST_LANG_CXX11=1",
+
+      # Prevents gtest from including both <tr1/tuple> and <tuple>.
+      "GTEST_HAS_TR1_TUPLE=0",
+    ]
+
+    sources = [
+      "external/googletest/googletest/include/gtest/gtest-death-test.h",
+      "external/googletest/googletest/include/gtest/gtest-message.h",
+      "external/googletest/googletest/include/gtest/gtest-param-test.h",
+      "external/googletest/googletest/include/gtest/gtest-printers.h",
+      "external/googletest/googletest/include/gtest/gtest-spi.h",
+      "external/googletest/googletest/include/gtest/gtest-test-part.h",
+      "external/googletest/googletest/include/gtest/gtest-typed-test.h",
+      "external/googletest/googletest/include/gtest/gtest.h",
+      "external/googletest/googletest/include/gtest/gtest_pred_impl.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-death-test-internal.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-filepath.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-internal.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-linked_ptr.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-param-util-generated.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-param-util.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-port.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-string.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-tuple.h",
+      "external/googletest/googletest/include/gtest/internal/gtest-type-util.h",
+      "external/googletest/googletest/src/gtest-death-test.cc",
+      "external/googletest/googletest/src/gtest-filepath.cc",
+      "external/googletest/googletest/src/gtest-internal-inl.h",
+      "external/googletest/googletest/src/gtest-port.cc",
+      "external/googletest/googletest/src/gtest-printers.cc",
+      "external/googletest/googletest/src/gtest-test-part.cc",
+      "external/googletest/googletest/src/gtest-typed-test.cc",
+      "external/googletest/googletest/src/gtest.cc",
+    ]
+
+    include_dirs = [
+      "external/googletest/googletest/include",
+      "external/googletest/googletest/",
+    ]
+
+    configs -= [ "//build/config/compiler:chromium_code" ]
+    configs += [ "//build/config/compiler:no_chromium_code" ]
+  }
+
+  static_library("gmock") {
+    testonly = true
+    sources = [
+      "external/googletest/googlemock/include/gmock/gmock-actions.h",
+      "external/googletest/googlemock/include/gmock/gmock-cardinalities.h",
+      "external/googletest/googlemock/include/gmock/gmock-generated-actions.h",
+      "external/googletest/googlemock/include/gmock/gmock-generated-function-mockers.h",
+      "external/googletest/googlemock/include/gmock/gmock-generated-matchers.h",
+      "external/googletest/googlemock/include/gmock/gmock-generated-nice-strict.h",
+      "external/googletest/googlemock/include/gmock/gmock-matchers.h",
+      "external/googletest/googlemock/include/gmock/gmock-spec-builders.h",
+      "external/googletest/googlemock/include/gmock/gmock.h",
+      "external/googletest/googlemock/include/gmock/internal/gmock-generated-internal-utils.h",
+      "external/googletest/googlemock/include/gmock/internal/gmock-internal-utils.h",
+      "external/googletest/googlemock/include/gmock/internal/gmock-port.h",
+      "external/googletest/googlemock/src/gmock-cardinalities.cc",
+      "external/googletest/googlemock/src/gmock-internal-utils.cc",
+      "external/googletest/googlemock/src/gmock-matchers.cc",
+      "external/googletest/googlemock/src/gmock-spec-builders.cc",
+      "external/googletest/googlemock/src/gmock.cc",
+    ]
+
+    include_dirs = [
+      "external/googletest/googletest/include",
+      "external/googletest/googlemock/include",
+    ]
+  }
+}
+
+config("spvtools_test_config") {
+  if (is_clang) {
+    cflags = [ "-Wno-self-assign" ]
+  }
+}
+
+test("spvtools_test") {
+  sources = [
+    "test/assembly_context_test.cpp",
+    "test/assembly_format_test.cpp",
+    "test/binary_destroy_test.cpp",
+    "test/binary_endianness_test.cpp",
+    "test/binary_header_get_test.cpp",
+    "test/binary_parse_test.cpp",
+    "test/binary_strnlen_s_test.cpp",
+    "test/binary_to_text.literal_test.cpp",
+    "test/binary_to_text_test.cpp",
+    "test/comment_test.cpp",
+    "test/enum_set_test.cpp",
+    "test/enum_string_mapping_test.cpp",
+    "test/ext_inst.debuginfo_test.cpp",
+    "test/ext_inst.glsl_test.cpp",
+    "test/ext_inst.opencl_test.cpp",
+    "test/fix_word_test.cpp",
+    "test/generator_magic_number_test.cpp",
+    "test/hex_float_test.cpp",
+    "test/immediate_int_test.cpp",
+    "test/libspirv_macros_test.cpp",
+    "test/name_mapper_test.cpp",
+    "test/named_id_test.cpp",
+    "test/opcode_make_test.cpp",
+    "test/opcode_require_capabilities_test.cpp",
+    "test/opcode_split_test.cpp",
+    "test/opcode_table_get_test.cpp",
+    "test/operand_capabilities_test.cpp",
+    "test/operand_pattern_test.cpp",
+    "test/operand_test.cpp",
+    "test/target_env_test.cpp",
+    "test/test_fixture.h",
+    "test/text_advance_test.cpp",
+    "test/text_destroy_test.cpp",
+    "test/text_literal_test.cpp",
+    "test/text_start_new_inst_test.cpp",
+    "test/text_to_binary.annotation_test.cpp",
+    "test/text_to_binary.barrier_test.cpp",
+    "test/text_to_binary.constant_test.cpp",
+    "test/text_to_binary.control_flow_test.cpp",
+    "test/text_to_binary.debug_test.cpp",
+    "test/text_to_binary.device_side_enqueue_test.cpp",
+    "test/text_to_binary.extension_test.cpp",
+    "test/text_to_binary.function_test.cpp",
+    "test/text_to_binary.group_test.cpp",
+    "test/text_to_binary.image_test.cpp",
+    "test/text_to_binary.literal_test.cpp",
+    "test/text_to_binary.memory_test.cpp",
+    "test/text_to_binary.misc_test.cpp",
+    "test/text_to_binary.mode_setting_test.cpp",
+    "test/text_to_binary.pipe_storage_test.cpp",
+    "test/text_to_binary.reserved_sampling_test.cpp",
+    "test/text_to_binary.subgroup_dispatch_test.cpp",
+    "test/text_to_binary.type_declaration_test.cpp",
+    "test/text_to_binary_test.cpp",
+    "test/text_word_get_test.cpp",
+    "test/unit_spirv.cpp",
+    "test/unit_spirv.h",
+  ]
+
+  deps = [
+    ":spvtools",
+  ]
+
+  if (build_with_chromium) {
+    deps += [
+      "//testing/gmock",
+      "//testing/gtest",
+      "//testing/gtest:gtest_main",
+    ]
+  } else {
+    deps += [
+      ":gmock",
+      ":gtest",
+    ]
+
+    sources += [ "external/googletest/googletest/src/gtest_main.cc" ]
+
+    include_dirs = [
+      "external/googletest/googletest/include",
+      "external/googletest/googlemock/include",
+    ]
+  }
+
+  configs += [
+    ":spvtools_config",
+    ":spvtools_test_config",
+  ]
+}
+
+if (!build_with_chromium) {
+  group("fuzzers") {
+    testonly = true
+    deps = [
+      "//testing/fuzzers",
+    ]
+  }
+}
diff --git a/DEPS b/DEPS
index 4ce20c87..a1f24fce 100644
--- a/DEPS
+++ b/DEPS
@@ -4,15 +4,20 @@ vars = {
   'chromium_git': 'https://chromium.googlesource.com',
   'github': 'https://github.com',
 
+  'build_revision': '037f38ae0fe5e11b4f7c33b750fd7a1e9634a606',
   'buildtools_revision': 'ab7b6a7b350dd15804c87c20ce78982811fdd76f',
   'clang_revision': 'abe5e4f9dc0f1df848c7a0efa05256253e77a7b7',
   'effcee_revision': '04b624799f5a9dbaf3fa1dbed2ba9dce2fc8dcf2',
   'googletest_revision': '98a0d007d7092b72eea0e501bb9ad17908a1a036',
+  'libfuzzer_revision': 'c24c2cd3f4d6130e815b6baff8165e4df440d442',
   're2_revision': '6cf8ccd82dbaab2668e9b13596c68183c9ecd13f',
   'spirv_headers_revision': 'ff684ffc6a35d2a58f0f63108877d0064ea33feb',
 }
 
 deps = {
+  "build":
+    Var('chromium_git') + "/chromium/src/build.git@" + Var('build_revision'),
+
   'buildtools':
       Var('chromium_git') + '/chromium/buildtools.git@' +
           Var('buildtools_revision'),
@@ -30,6 +35,10 @@ deps = {
   'external/re2':
       Var('github') + '/google/re2.git@' + Var('re2_revision'),
 
+  'testing/libfuzzer':
+      Var('chromium_git') + '/chromium/src/testing/libfuzzer@' +
+          Var('libfuzzer_revision'),
+
   'tools/clang':
       Var('chromium_git') + '/chromium/src/tools/clang@' + Var('clang_revision')
 }
@@ -40,6 +49,38 @@ recursedeps = [
 ]
 
 hooks = [
+  {
+    'name': 'gn_win',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=win32',
+                '--no_auth',
+                '--bucket', 'chromium-gn',
+                '-s', 'SPIRV-Tools/buildtools/win/gn.exe.sha1',
+    ],
+  },
+  {
+    'name': 'gn_mac',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=darwin',
+                '--no_auth',
+                '--bucket', 'chromium-gn',
+                '-s', 'SPIRV-Tools/buildtools/mac/gn.sha1',
+    ],
+  },
+  {
+    'name': 'gn_linux64',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=linux*',
+                '--no_auth',
+                '--bucket', 'chromium-gn',
+                '-s', 'SPIRV-Tools/buildtools/linux64/gn.sha1',
+    ],
+  },
   # Pull clang-format binaries using checked-in hashes.
   {
     'name': 'clang_format_win',
@@ -82,4 +123,52 @@ hooks = [
                'SPIRV-Tools/tools/clang/scripts/update.py'
     ],
   },
+  {
+    'name': 'sysroot_arm',
+    'pattern': '.',
+    'condition': 'checkout_linux and checkout_arm',
+    'action': ['python', 'SPIRV-Tools/build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=arm'],
+  },
+  {
+    'name': 'sysroot_arm64',
+    'pattern': '.',
+    'condition': 'checkout_linux and checkout_arm64',
+    'action': ['python', 'SPIRV-Tools/build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=arm64'],
+  },
+  {
+    'name': 'sysroot_x86',
+    'pattern': '.',
+    'condition': 'checkout_linux and (checkout_x86 or checkout_x64)',
+    'action': ['python', 'SPIRV-Tools/build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=x86'],
+  },
+  {
+    'name': 'sysroot_mips',
+    'pattern': '.',
+    'condition': 'checkout_linux and checkout_mips',
+    'action': ['python', 'SPIRV-Tools/build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=mips'],
+  },
+  {
+    'name': 'sysroot_x64',
+    'pattern': '.',
+    'condition': 'checkout_linux and checkout_x64',
+    'action': ['python', 'SPIRV-Tools/build/linux/sysroot_scripts/install-sysroot.py',
+               '--arch=x64'],
+  },
+  {
+    # Update the Windows toolchain if necessary.
+    'name': 'win_toolchain',
+    'pattern': '.',
+    'condition': 'checkout_win',
+    'action': ['python', 'SPIRV-Tools/build/vs_toolchain.py', 'update', '--force'],
+  },
+  {
+    # Update the Mac toolchain if necessary.
+    'name': 'mac_toolchain',
+    'pattern': '.',
+    'action': ['python', 'SPIRV-Tools/build/mac_toolchain.py'],
+  },
 ]
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
new file mode 100644
index 00000000..833fcd34
--- /dev/null
+++ b/build_overrides/build.gni
@@ -0,0 +1,46 @@
+# Copyright 2018 Google Inc.
+#
+# 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
+#
+#     https://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.
+
+# 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
+
+# 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/gtest.gni b/build_overrides/gtest.gni
new file mode 100644
index 00000000..c8b1bae4
--- /dev/null
+++ b/build_overrides/gtest.gni
@@ -0,0 +1,25 @@
+# Copyright 2018 Google Inc.
+#
+# 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
+#
+#     https://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.
+
+# Exclude support for registering main function in multi-process tests.
+gtest_include_multiprocess = false
+
+# Exclude support for platform-specific operations across unit tests.
+gtest_include_platform_test = false
+
+# Exclude support for testing Objective C code on OS X and iOS.
+gtest_include_objc_support = false
+
+# Exclude support for flushing coverage files on iOS.
+gtest_include_ios_coverage = false
diff --git a/testing/fuzzers/BUILD.gn b/testing/fuzzers/BUILD.gn
new file mode 100644
index 00000000..b8777ecd
--- /dev/null
+++ b/testing/fuzzers/BUILD.gn
@@ -0,0 +1,89 @@
+# Copyright 2018 Google Inc. 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.
+
+import("//testing/libfuzzer/fuzzer_test.gni")
+import("//testing/test.gni")
+
+config("fuzzer_config") {
+  configs = [ "../..:spvtools_config" ]
+}
+
+group("fuzzers") {
+  testonly = true
+  deps = []
+
+  if (!build_with_chromium || use_fuzzing_engine) {
+    deps += [ ":fuzzers_bin" ]
+  }
+}
+
+group("fuzzers_bin") {
+  testonly = true
+
+  deps = [
+    ":spvtools_opt_fuzzer",
+    ":spvtools_val_fuzzer",
+  ]
+}
+
+template("spvtools_fuzzer") {
+  source_set(target_name) {
+    testonly = true
+    sources = invoker.sources
+    deps = [
+      "../..:spvtools",
+      "../..:spvtools_opt",
+      "../..:spvtools_val",
+    ]
+    if (defined(invoker.deps)) {
+      deps += invoker.deps
+    }
+
+    configs -= [ "//build/config/compiler:chromium_code" ]
+    configs += [
+      "//build/config/compiler:no_chromium_code",
+      ":fuzzer_config",
+    ]
+  }
+}
+
+spvtools_fuzzer("spvtools_opt_fuzzer_src") {
+  sources = [
+    "spvtools_opt_fuzzer.cpp",
+  ]
+}
+
+spvtools_fuzzer("spvtools_val_fuzzer_src") {
+  sources = [
+    "spvtools_val_fuzzer.cpp",
+  ]
+}
+
+if (!build_with_chromium || use_fuzzing_engine) {
+  fuzzer_test("spvtools_opt_fuzzer") {
+    sources = []
+    deps = [
+      ":spvtools_opt_fuzzer_src",
+    ]
+    seed_corpus = "corpora/spv"
+  }
+
+  fuzzer_test("spvtools_val_fuzzer") {
+    sources = []
+    deps = [
+      ":spvtools_val_fuzzer_src",
+    ]
+    seed_corpus = "corpora/spv"
+  }
+}
diff --git a/testing/fuzzers/corpora/spv/simple.spv b/testing/fuzzers/corpora/spv/simple.spv
new file mode 100644
index 00000000..f972a56f
Binary files /dev/null and b/testing/fuzzers/corpora/spv/simple.spv differ
diff --git a/testing/fuzzers/spvtools_opt_fuzzer.cpp b/testing/fuzzers/spvtools_opt_fuzzer.cpp
new file mode 100644
index 00000000..20ded9a0
--- /dev/null
+++ b/testing/fuzzers/spvtools_opt_fuzzer.cpp
@@ -0,0 +1,36 @@
+// Copyright (c) 2018 Google Inc.
+//
+// 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 <cstdint>
+
+#include "spirv-tools/optimizer.hpp"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  spvtools::Optimizer optimizer(SPV_ENV_UNIVERSAL_1_3);
+  optimizer.SetMessageConsumer([](spv_message_level_t, const char*,
+                                  const spv_position_t&, const char*) {});
+
+  std::vector<uint32_t> input;
+  input.resize(size >> 2);
+
+  size_t count = 0;
+  for (size_t i = 0; (i + 3) < size; i += 4) {
+    input[count++] = data[i] | (data[i + 1] << 8) | (data[i + 2] << 16) |
+                     (data[i + 3]) << 24;
+  }
+
+  optimizer.Run(input.data(), input.size(), &input);
+
+  return 0;
+}
diff --git a/testing/fuzzers/spvtools_val_fuzzer.cpp b/testing/fuzzers/spvtools_val_fuzzer.cpp
new file mode 100644
index 00000000..9b06a1f6
--- /dev/null
+++ b/testing/fuzzers/spvtools_val_fuzzer.cpp
@@ -0,0 +1,35 @@
+// Copyright (c) 2018 Google Inc.
+//
+// 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 <cstdint>
+
+#include "spirv-tools/libspirv.hpp"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  spvtools::SpirvTools tools(SPV_ENV_UNIVERSAL_1_3);
+  tools.SetMessageConsumer([](spv_message_level_t, const char*,
+                              const spv_position_t&, const char*) {});
+
+  std::vector<uint32_t> input;
+  input.resize(size >> 2);
+
+  size_t count = 0;
+  for (size_t i = 0; (i + 3) < size; i += 4) {
+    input[count++] = data[i] | (data[i + 1] << 8) | (data[i + 2] << 16) |
+                     (data[i + 3]) << 24;
+  }
+
+  tools.Validate(input);
+  return 0;
+}
diff --git a/testing/test.gni b/testing/test.gni
new file mode 100644
index 00000000..d42fe52c
--- /dev/null
+++ b/testing/test.gni
@@ -0,0 +1,413 @@
+# Copyright 2018 The Chromium Authors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#    * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#    * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# ==============================================================================
+# TEST SETUP
+# ==============================================================================
+
+if (is_android) {
+  import("//build/config/android/config.gni")
+  import("//build/config/android/rules.gni")
+  import("//build/config/sanitizers/sanitizers.gni")
+  import("//build/config/android/extract_unwind_tables.gni")
+}
+
+if (is_fuchsia) {
+  import("//build/config/chromecast_build.gni")
+  import("//build/config/fuchsia/rules.gni")
+  import("//build/config/fuchsia/package.gni")
+}
+
+if (is_chromeos) {
+  import("//build/config/chromeos/rules.gni")
+}
+
+# Define a test as an executable (or apk on Android) with the "testonly" flag
+# set.
+# Variable:
+#   use_raw_android_executable: Use executable() rather than android_apk().
+#   use_native_activity: Test implements ANativeActivity_onCreate().
+template("test") {
+  if (is_android) {
+    _use_raw_android_executable = defined(invoker.use_raw_android_executable) &&
+                                  invoker.use_raw_android_executable
+
+    # output_name is used to allow targets with the same name but in different
+    # packages to still produce unique runner scripts.
+    _output_name = invoker.target_name
+    if (defined(invoker.output_name)) {
+      _output_name = invoker.output_name
+    }
+
+    _test_runner_target = "${_output_name}__test_runner_script"
+    _wrapper_script_vars = [
+      "ignore_all_data_deps",
+      "shard_timeout",
+    ]
+
+    assert(_use_raw_android_executable || enable_java_templates)
+
+    _incremental_apk_only =
+        incremental_apk_by_default && !_use_raw_android_executable
+
+    if (_use_raw_android_executable) {
+      _exec_target = "${target_name}__exec"
+      _dist_target = "${target_name}__dist"
+      _exec_output =
+          "$target_out_dir/${invoker.target_name}/${invoker.target_name}"
+
+      executable(_exec_target) {
+        # Configs will always be defined since we set_defaults in BUILDCONFIG.gn.
+        configs = []
+        data_deps = []
+        forward_variables_from(invoker,
+                               "*",
+                               _wrapper_script_vars + [ "extra_dist_files" ])
+        testonly = true
+
+        # Thanks to the set_defaults() for test(), configs are initialized with
+        # the default shared_library configs rather than executable configs.
+        configs -= [
+          "//build/config:shared_library_config",
+          "//build/config/android:hide_all_but_jni",
+        ]
+        configs += [ "//build/config:executable_config" ]
+
+        # Don't output to the root or else conflict with the group() below.
+        output_name = rebase_path(_exec_output, root_out_dir)
+        if (is_component_build || is_asan) {
+          data_deps += [ "//build/android:cpplib_stripped" ]
+        }
+      }
+
+      create_native_executable_dist(_dist_target) {
+        testonly = true
+        dist_dir = "$root_out_dir/$target_name"
+        binary = _exec_output
+        deps = [
+          ":$_exec_target",
+        ]
+        if (defined(invoker.extra_dist_files)) {
+          extra_files = invoker.extra_dist_files
+        }
+      }
+    } else {
+      _library_target = "_${target_name}__library"
+      _apk_target = "${target_name}_apk"
+      _apk_specific_vars = [
+        "android_manifest",
+        "android_manifest_dep",
+        "enable_multidex",
+        "proguard_configs",
+        "proguard_enabled",
+        "use_default_launcher",
+        "write_asset_list",
+        "use_native_activity",
+      ]
+
+      # Adds the unwind tables from unstripped binary as an asset file in the
+      # apk, if |add_unwind_tables_in_apk| is specified by the test.
+      if (defined(invoker.add_unwind_tables_in_apk) &&
+          invoker.add_unwind_tables_in_apk) {
+        _unwind_table_asset_name = "${target_name}_unwind_assets"
+        unwind_table_asset(_unwind_table_asset_name) {
+          testonly = true
+          library_target = _library_target
+          deps = [
+            ":$_library_target",
+          ]
+        }
+      }
+
+      shared_library(_library_target) {
+        # Configs will always be defined since we set_defaults in BUILDCONFIG.gn.
+        configs = []  # Prevent list overwriting warning.
+        configs = invoker.configs
+        testonly = true
+
+        deps = []
+        forward_variables_from(
+            invoker,
+            "*",
+            _apk_specific_vars + _wrapper_script_vars + [ "visibility" ])
+
+        if (!defined(invoker.use_default_launcher) ||
+            invoker.use_default_launcher) {
+          deps += [ "//testing/android/native_test:native_test_native_code" ]
+        }
+      }
+      unittest_apk(_apk_target) {
+        forward_variables_from(invoker, _apk_specific_vars + [ "deps" ])
+        shared_library = ":$_library_target"
+        apk_name = invoker.target_name
+        if (defined(invoker.output_name)) {
+          apk_name = invoker.output_name
+          install_script_name = "install_${invoker.output_name}"
+        }
+
+        # Add the Java classes so that each target does not have to do it.
+        deps += [ "//base/test:test_support_java" ]
+
+        if (defined(_unwind_table_asset_name)) {
+          deps += [ ":${_unwind_table_asset_name}" ]
+        }
+
+        # TODO(agrieve): Remove this data_dep once bots don't build the _apk
+        #     target (post-GYP).
+        # It's a bit backwards for the apk to depend on the runner script, since
+        # the apk is conceptually a runtime_dep of the script. However, it is
+        # currently necessary because the bots build this _apk target directly
+        # rather than the group() below.
+        data_deps = [
+          ":$_test_runner_target",
+        ]
+      }
+
+      _test_runner_target = "${_output_name}__test_runner_script"
+      _incremental_test_name = "${_output_name}_incremental"
+      _incremental_test_runner_target =
+          "${_output_name}_incremental__test_runner_script"
+      if (_incremental_apk_only) {
+        _incremental_test_name = _output_name
+        _incremental_test_runner_target = _test_runner_target
+      }
+
+      # Incremental test targets work only for .apks.
+      test_runner_script(_incremental_test_runner_target) {
+        forward_variables_from(invoker,
+                               _wrapper_script_vars + [
+                                     "data",
+                                     "data_deps",
+                                     "deps",
+                                     "public_deps",
+                                   ])
+        apk_target = ":$_apk_target"
+        test_name = _incremental_test_name
+        test_type = "gtest"
+        test_suite = _output_name
+        incremental_install = true
+      }
+      group("${target_name}_incremental") {
+        testonly = true
+        data_deps = [
+          ":$_incremental_test_runner_target",
+        ]
+        deps = [
+          ":${_apk_target}_incremental",
+        ]
+      }
+    }
+
+    if (!_incremental_apk_only) {
+      test_runner_script(_test_runner_target) {
+        forward_variables_from(invoker,
+                               _wrapper_script_vars + [
+                                     "data",
+                                     "data_deps",
+                                     "deps",
+                                     "public_deps",
+                                   ])
+
+        if (_use_raw_android_executable) {
+          executable_dist_dir = "$root_out_dir/$_dist_target"
+        } else {
+          apk_target = ":$_apk_target"
+        }
+        test_name = _output_name
+        test_type = "gtest"
+        test_suite = _output_name
+      }
+    }
+
+    test_runner_script(target_name) {
+      forward_variables_from(invoker,
+                             _wrapper_script_vars + [
+                                   "data",
+                                   "data_deps",
+                                   "deps",
+                                   "public_deps",
+                                 ])
+
+      if (_use_raw_android_executable) {
+        executable_dist_dir = "$root_out_dir/$_dist_target"
+        deps += [
+          ":$_dist_target",
+          ":$_test_runner_target",
+        ]
+      } else {
+        apk_target = ":$_apk_target"
+        deps += [ ":$_apk_target" ]
+        if (_incremental_apk_only) {
+          deps += [ ":${target_name}_incremental" ]
+        } else {
+          deps += [ ":$_test_runner_target" ]
+        }
+      }
+      generated_script = "$root_build_dir/$_output_name"
+      incremental_install = _incremental_apk_only
+      test_name = _output_name
+      test_suite = _output_name
+      test_type = "gtest"
+    }
+  } else if (is_fuchsia) {
+    _output_name = invoker.target_name
+    _pkg_target = "${_output_name}_pkg"
+    _gen_runner_target = "${_output_name}_runner"
+    _exec_target = "${_output_name}__exec"
+
+    group(target_name) {
+      testonly = true
+      deps = [
+        ":$_gen_runner_target",
+        ":$_pkg_target",
+      ]
+    }
+
+    # Makes the script which invokes the executable.
+    test_runner_script(_gen_runner_target) {
+      forward_variables_from(invoker, [ "use_test_server" ])
+      test_name = _output_name
+      package_name = _output_name
+    }
+
+    executable(_exec_target) {
+      testonly = true
+      forward_variables_from(invoker, "*")
+      output_name = _exec_target
+    }
+
+    package(_pkg_target) {
+      testonly = true
+      package_name = _output_name
+      sandbox_policy = "//build/config/fuchsia/testing_sandbox_policy"
+      binary = get_label_info(_exec_target, "name")
+      deps = [
+        ":$_exec_target",
+      ]
+    }
+  } else if (is_ios) {
+    import("//build/config/ios/ios_sdk.gni")
+    import("//build/config/ios/rules.gni")
+
+    _test_target = target_name
+    _resources_bundle_data = target_name + "_resources_bundle_data"
+
+    bundle_data(_resources_bundle_data) {
+      visibility = [ ":$_test_target" ]
+      sources = [
+        "//testing/gtest_ios/Default.png",
+      ]
+      outputs = [
+        "{{bundle_resources_dir}}/{{source_file_part}}",
+      ]
+    }
+
+    ios_app_bundle(_test_target) {
+      testonly = true
+
+      # See above call.
+      set_sources_assignment_filter([])
+      forward_variables_from(invoker, "*", [ "testonly" ])
+
+      # Provide sensible defaults in case invoker did not define any of those
+      # required variables.
+      if (!defined(info_plist) && !defined(info_plist_target)) {
+        info_plist = "//testing/gtest_ios/unittest-Info.plist"
+      }
+
+      _bundle_id_suffix = ios_generic_test_bundle_id_suffix
+      if (!ios_automatically_manage_certs) {
+        _bundle_id_suffix = "${target_name}"
+      }
+      if (!defined(extra_substitutions)) {
+        extra_substitutions = []
+      }
+      extra_substitutions += [ "GTEST_BUNDLE_ID_SUFFIX=$_bundle_id_suffix" ]
+
+      if (!defined(bundle_deps)) {
+        bundle_deps = []
+      }
+      bundle_deps += [ ":$_resources_bundle_data" ]
+    }
+  } else if (is_chromeos && cros_board != "") {
+    # When the arg cros_board is set, assume we're in the cros chrome-sdk
+    # building simplechrome.
+
+    _gen_runner_target = "${target_name}__runner"
+    _runtime_deps_file =
+        "$root_out_dir/gen.runtime/" + get_label_info(target_name, "dir") +
+        "/" + get_label_info(target_name, "name") + ".runtime_deps"
+
+    generate_vm_runner_script(_gen_runner_target) {
+      testonly = true
+      generated_script = "$root_build_dir/bin/run_" + invoker.target_name
+      test_exe = "$root_out_dir/" + get_label_info(invoker.target_name, "name")
+      runtime_deps_file = _runtime_deps_file
+    }
+
+    executable(target_name) {
+      forward_variables_from(invoker, "*")
+      if (!defined(deps)) {
+        deps = []
+      }
+      if (!defined(data)) {
+        data = []
+      }
+
+      testonly = true
+      output_name = target_name
+      write_runtime_deps = _runtime_deps_file
+      data += [ _runtime_deps_file ]
+      deps += [ ":$_gen_runner_target" ]
+    }
+  } else {
+    executable(target_name) {
+      forward_variables_from(invoker, "*")
+      if (!defined(deps)) {
+        deps = []
+      }
+
+      testonly = true
+      deps += [
+        # Give tests the default manifest on Windows (a no-op elsewhere).
+        "//build/win:default_exe_manifest",
+      ]
+    }
+  }
+}
+
+# Test defaults.
+set_defaults("test") {
+  if (is_android) {
+    configs = default_shared_library_configs
+    configs -= [ "//build/config/android:hide_all_but_jni_onload" ]
+    configs += [ "//build/config/android:hide_all_but_jni" ]
+  } else {
+    configs = default_executable_configs
+  }
+}