common-mk/BUILDCONFIG.gn

# Copyright 2018 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

declare_args() {
  # The OS build is running on.
  OS = ""

  # Specifies pkg-config program to retrieve information about packages.
  pkg_config = ""

  # The logical root directory for headers and libraries.
  # Trailing slash should not be added (except root path).
  sysroot = ""

  # The libdir of the target board. e.g. /usr/lib64
  libdir = ""

  # The path to the directory where build artifacts are located.
  build_root = ""

  # The path to src/platform2.
  platform2_root = ""

  # Libbase revision number read from BASE_VER variable or file.
  libbase_ver = ""

  # Set true to allow C++ code to use exceptions.
  enable_exceptions = false

  # Set true if clang is used for C compiler.
  clang_cc = false

  # Set true if clang is used for C++ compiler.
  clang_cxx = false

  # Additional flags for C compiler.
  external_cflags = []

  # Additional flags for C++ compiler.
  external_cxxflags = []

  # Additional flags for C and C++ preprocessor.
  external_cppflags = []

  # Additional flags for C and C++ linker.
  external_ldflags = []
}
import("//common-mk/use.gni")

assert(pkg_config != "", "pkg-config script path must be set")
assert(libbase_ver != -1, "libbase_ver must be set")
assert(libdir != "", "libdir must be set")

if (target_os == "") {
  target_os = host_os
}
if (target_cpu == "") {
  target_cpu = host_cpu
}
if (current_cpu == "") {
  current_cpu = target_cpu
}
if (current_os == "") {
  current_os = target_os
}

# Practically sysroot is used as a prefix of paths, e.g.
# "${sysroot}/usr/include". If sysroot is root (= "/"), it will be
# "//usr/include". However, in GN, paths starting with "//" represents the path
# to the GN root, rather than the file system root, which is unexpected.
# To support that case, replace sysroot with "/.", if sysroot is "/".
if (sysroot == "/") {
  sysroot = "/."
}

# All binary targets will get this list of configs by default.
_binary_target_configs = [ "//common-mk:compiler_defaults" ]

if (!enable_exceptions) {
  _binary_target_configs += [ "//common-mk:no_exceptions" ]
}

if (!clang_cc) {
  _binary_target_configs += [ "//common-mk:gcc_cflags_c" ]
}
if (!clang_cxx) {
  _binary_target_configs += [ "//common-mk:gcc_cflags_cc" ]
}

set_defaults("executable") {
  configs = _binary_target_configs
  configs += [ "//common-mk:pie" ]
}

set_defaults("static_library") {
  configs = _binary_target_configs
  configs += [
    "//common-mk:pie",
    "//common-mk:use_thin_archive",
  ]
}

set_defaults("shared_library") {
  configs = _binary_target_configs
  configs += [ "//common-mk:pic" ]
}

set_defaults("source_set") {
  configs = _binary_target_configs
}

set_default_toolchain("//common-mk/toolchain")

# In Chrome OS, pkg-config is commonly and widely used.
# It is not natively supported by GN. Instead, here a few special fields are
# injected to the executable, shared_library and static_library targets
# to support pkg-config.
#
# Args:
#   pkg_deps(optional): A list of package names to be depend.
#     A corresponding config is created, and then injected to |configs|.
#   public_pkg_deps(optional): Similart to pkg_deps, but injected to
#     |public_configs| instead.
#   all_dependent_pkg_deps(optional): Similar to pkg_deps, but injected to
#     |all_dependent_pkg_deps|.

import("//common-mk/pkg_config.gni")

template("_generate_config_rule") {
  if (defined(invoker.pkg_deps) && invoker.pkg_deps != []) {
    _pkg_deps_name = "_${target_name}-pkg_deps-config"
    pkg_config(_pkg_deps_name) {
      pkg_deps = invoker.pkg_deps
    }
  }
  if (defined(invoker.public_pkg_deps) && invoker.public_pkg_deps != []) {
    _public_pkg_deps_name = "_${target_name}-public_pkg_deps-config"
    pkg_config(_public_pkg_deps_name) {
      pkg_deps = invoker.public_pkg_deps
    }
  }
  if (defined(invoker.all_dependent_pkg_deps) &&
      invoker.all_dependent_pkg_deps != []) {
    _all_dependent_pkg_deps_name =
        "_${target_name}-all_dependent_pkg_deps-config"
    pkg_config(_all_dependent_pkg_deps_name) {
      pkg_deps = invoker.all_dependent_pkg_deps
    }
  }

  target(invoker.target_type, target_name) {
    forward_variables_from(invoker,
                           "*",
                           [
                             "all_dependent_pkg_deps",
                             "pkg_deps",
                             "public_pkg_deps",
                             "target_type",
                           ])
    if (defined(_pkg_deps_name)) {
      if (!defined(configs)) {
        configs = []
      }
      configs += [ ":${_pkg_deps_name}" ]
    }
    if (defined(_public_pkg_deps_name)) {
      if (!defined(public_configs)) {
        public_configs = []
      }
      public_configs += [ ":${_public_pkg_deps_name}" ]
    }
    if (defined(_all_dependent_pkg_deps_name)) {
      if (!defined(all_dependent_configs)) {
        all_dependent_configs = []
      }
      all_dependent_configs += [ ":${_all_dependent_pkg_deps_name}" ]
    }
  }
}

template("executable") {
  _generate_config_rule(target_name) {
    forward_variables_from(invoker, "*")
    target_type = "executable"
  }
}

template("shared_library") {
  _generate_config_rule(target_name) {
    forward_variables_from(invoker, "*")
    target_type = "shared_library"
  }
}

template("static_library") {
  _generate_config_rule(target_name) {
    forward_variables_from(invoker, "*")
    target_type = "static_library"
  }
}