common-mk/BUILD.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() {
  # Set this to false if you'd like to disable -Werror.
  enable_werror = true

  # Set this to false if you want to disable Large File Support (LFS).
  enable_lfs = true
}

_cflags_no_exceptions = [
  "-fno-exceptions",
  "-fno-unwind-tables",
  "-fno-asynchronous-unwind-tables",
]

config("no_exceptions") {
  cflags_cc = _cflags_no_exceptions
  cflags_c = _cflags_no_exceptions
}

# Symbol visibility is set to be internal by default. Add this to your target's
# configs to make its symbols visible.
# Setting "-fvisibility=default" directly in your target's cflags doesn't work
# because it will be overwritten by the "-fvisibility=internal" in the
# compiler_defaults' cflags.
config("visibility_default") {
  cflags = [ "-fvisibility=default" ]
}

config("compiler_defaults") {
  defines = []
  libs = []

  include_dirs = [
    "${root_gen_dir}/include",
    "${platform2_root}",
  ]
  cflags = [
    "-Wall",
    "-Wno-psabi",
    "-Wunused",
    "-Wno-unused-parameter",
    "-ggdb3",
    "-fstack-protector-strong",
    "-Wformat=2",
    "-fvisibility=internal",
    "-Wa,--noexecstack",
  ]
  cflags_c = [ "-std=gnu11" ] + external_cppflags + external_cxxflags
  cflags_cc = [ "-std=gnu++14" ] + external_cppflags + external_cxxflags
  ldflags = external_ldflags + [
              "-Wl,-z,relro",
              "-Wl,-z,noexecstack",
              "-Wl,-z,now",
              "-Wl,--as-needed",
            ]
  if (enable_werror) {
    cflags += [ "-Werror" ]
  }
  if (use.cros_host) {
    defines += [ "NDEBUG" ]
  }
  if (enable_lfs) {
    defines += [
      # Enable support for new LFS funcs (ftello/etc...).
      "_LARGEFILE_SOURCE",

      # Enable support for 64bit variants (off64_t/fseeko64/etc...).
      "_LARGEFILE64_SOURCE",

      # Default to 64bit variants (off_t is defined as off64_t).
      "_FILE_OFFSET_BITS=64",
    ]
  }

  # Remove no_exceptions flags given as arguments making the config pluggable.
  # See BUILDCONFIG.gn.
  cflags_cc -= _cflags_no_exceptions
  cflags_c -= _cflags_no_exceptions

  if (!use.cros_host) {
    include_dirs += [ "${sysroot}/usr/include" ]
    cflags += [ "--sysroot=${sysroot}" ]
    ldflags += [ "--sysroot=${sysroot}" ]
  }
  if (use.profiling) {
    cflags += [
      "-fprofile-instr-generate",
      "-fcoverage-mapping",
    ]
    ldflags += [
      "-fprofile-instr-generate",
      "-fcoverage-mapping",
    ]
  }
  if (use.tcmalloc) {
    libs += [ "-ltcmalloc" ]
  }
}

# Generates position independent executable.
# This is a default config for executables and static libraries.
config("pie") {
  cflags = [ "-fPIE" ]

  # ldflags are not pushed to dependents, so applying ldflags to source sets or
  # static libraries will be a no-op. You can just remove "pie" config from an
  # executable to make the executable not position independent.
  ldflags = [ "-pie" ]
}

# Use thin archive. It makes sense only for static libraries.
# This is a default config for static libraries.
config("use_thin_archive") {
  arflags = [ "rcsT" ]
}

# Generates position independent code.
# This is a default config for shared libraries.
config("pic") {
  cflags = [ "-fPIC" ]
}

if (use.test) {
  # This config should be at the top in the configs list, especially before
  # the config for libchrome-${libbase-ver} to avoid weird heap-buffer-overflow
  # error from happening when ASAN is enabled.
  # TODO(crbug.com/887845): Remove this note after library order issue is resolved.
  config("test") {
    libs = []

    # Don't worry about overlinking, ld.gold's --as-needed will
    # deal with that.
    libs += exec_script("//common-mk/args_generator_wrapper.py",
                        [
                          "gtest-config",
                          "--libs",
                        ],
                        "list lines")
    libs += exec_script("//common-mk/args_generator_wrapper.py",
                        [
                          "gmock-config",
                          "--libs",
                        ],
                        "list lines")
  }
}