third_party/libprotobuf-mutator/BUILD.gn

# Copyright 2017 The Chromium Authors. All rights reserved.
import("//build/config/sanitizers/sanitizers.gni")
import("//testing/libfuzzer/fuzzer_test.gni")
import("//third_party/protobuf/proto_library.gni")

config("include_config") {
  include_dirs = [ "src/" ]
}

source_set("libprotobuf-mutator") {
  testonly = true

  # Dont allow building on windows to avoid tryjob failure. This is OK since
  # libFuzzer doesn't build on windows anyway.
  if (!is_win) {
    configs += [ ":include_config" ]

    # Remove *San and coverage for a performance boost.
    configs -= not_fuzzed_remove_configs
    configs += [ "//build/config/sanitizers:not_fuzzed" ]

    public_configs = [ ":include_config" ]
    sources = [
      "src/src/binary_format.cc",
      "src/src/libfuzzer/libfuzzer_macro.cc",
      "src/src/libfuzzer/libfuzzer_mutator.cc",
      "src/src/mutator.cc",
      "src/src/text_format.cc",
      "src/src/utf8_fix.cc",
    ]

    # Allow users of LPM to use protobuf reflection and other features from
    # protobuf_full.
    public_deps = [
      "//third_party/protobuf:protobuf_full",
    ]

    # Let ClusterFuzz builders know to not build targets that depend on
    # libprotobuf-mutator for AFL.
    if (use_afl) {
      all_dependent_configs = [ "//testing/libfuzzer:no_clusterfuzz" ]
    }
  }
}

# This protoc plugin, like the compiler, should only be built for the host
# architecture.
if (current_toolchain == host_toolchain) {
  # This plugin will be needed to fuzz most protobuf code in Chromium. That's
  # because production protobuf code must contain the line:
  # "option optimize_for = LITE_RUNTIME", which instructs the proto compiler not
  # to compile the proto using the full protobuf runtime. This allows Chromium
  # not to depend on the full protobuf library, but prevents
  # libprotobuf-mutator from fuzzing because the lite runtime lacks needed
  # features (such as reflection).  The plugin simply compiles a proto library
  # as normal but ensures that is compiled with the full protobuf runtime.
  executable("override_lite_runtime_plugin") {
    sources = [
      "protoc_plugin/protoc_plugin.cc",
    ]
    deps = [
      "//third_party/protobuf:protoc_lib",
    ]
    public_configs = [ "//third_party/protobuf:protobuf_config" ]
  }
  # To use the plugin in a proto_library you want to fuzz, add these lines to
  # the proto_library definition (note the "=" in second to last line in the
  # comment will need to be changed to "+=" if you have already defined
  # deps):
  # if (use_libfuzzer && current_toolchain == host_toolchain) {
  #   generator_plugin_label =
  #     "//third_party/libprotobuf-mutator:override_lite_runtime_plugin"
  #   generator_plugin_suffix = ".pb"
  #   # The plugin will generate cc, so don't ask for it to be done by protoc.
  #   generate_cc = false
  #   deps = ["//third_party/libprotobuf-mutator:override_lite_runtime_plugin"]
  # }
}

# The CQ will try building this target without "use_libfuzzer" if it is defined.
# That will cause the build to fail, so don't define it when "use_libfuzzer" is
# is false.
if (use_libfuzzer) {
  # Test that override_lite_runtime_plugin is working when built. This target
  # contains files that are optimized for LITE_RUNTIME and which import other
  # files that are also optimized for LITE_RUNTIME.
  fuzzer_test("override_lite_runtime_plugin_test_fuzzer") {
    sources = [
      "protoc_plugin/test_fuzzer.cc",
    ]
    deps = [
      ":libprotobuf-mutator",
      ":override_lite_runtime_plugin_test_fuzzer_proto",
    ]

    # Don't actually run this on CF. It's only a test to ensure builds work.
    additional_configs = [ "//testing/libfuzzer:no_clusterfuzz" ]
  }
}

# Proto library for override_lite_runtime_plugin_test_fuzzer
proto_library("override_lite_runtime_plugin_test_fuzzer_proto") {
  sources = [
    "protoc_plugin/imported.proto",
    "protoc_plugin/imported_publicly.proto",
    "protoc_plugin/test_fuzzer_input.proto",
  ]

  # TODO(metzman): Figure out how we can avoid using this toolchain check
  # (maybe remove compilation from the plugin).
  if (use_libfuzzer && current_toolchain == host_toolchain) {
    generator_plugin_label =
        "//third_party/libprotobuf-mutator:override_lite_runtime_plugin"
    generator_plugin_suffix = ".pb"

    # The plugin will generate cc, so don't ask for it to be done by protoc.
    generate_cc = false
    deps = [
      "//third_party/libprotobuf-mutator:override_lite_runtime_plugin",
    ]
  }
}