Beginning work on GN build

build/config/BUILD.gn

Index: build/config/BUILD.gn
diff --git a/build/config/BUILD.gn b/build/config/BUILD.gn
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+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/allocator.gni")
+import("//build/config/chrome_build.gni")
+import("//build/config/chromecast_build.gni")
+import("//build/config/crypto.gni")
+import("//build/config/dcheck_always_on.gni")
+import("//build/config/features.gni")
+import("//build/config/sanitizers/sanitizers.gni")
+import("//build/config/ui.gni")
+import("//build/toolchain/goma.gni")
+
+# One common error that happens is that GYP-generated headers within gen/ get
+# included rather than the GN-generated ones within gen/ subdirectories.
+# TODO(GYP_GONE): Remove once GYP is gone (as well as exec_script exception).
+assert(
+    exec_script("//build/dir_exists.py", [ "obj.host" ], "string") == "False",
+    "GYP artifacts detected in $root_build_dir.$0x0A" +
+        "You must wipe this directory before building with GN.")
+
+declare_args() {
+  # When set (the default) enables C++ iterator debugging in debug builds.
+  # Iterator debugging is always off in release builds (technically, this flag
+  # affects the "debug" config, which is always available but applied by
+  # default only in debug builds).
+  #
+  # Iterator debugging is generally useful for catching bugs. But it can
+  # introduce extra locking to check the state of an iterator against the state
+  # of the current object. For iterator- and thread-heavy code, this can
+  # significantly slow execution.
+  enable_iterator_debugging = true
+
+  # Normally we try to decide whether to use precompiled headers or
+  # not based on the other build arguments, but in some cases it is
+  # easiest to force them off explicitly.
+  disable_precompiled_headers = false
+}
+
+# TODO(brettw) Most of these should be removed. Instead of global feature
+# flags, we should have more modular flags that apply only to a target and its
+# dependents. For example, depending on the "x11" meta-target should define
+# USE_X11 for all dependents so that everything that could use X11 gets the
+# define, but anything that doesn't depend on X11 doesn't see it.
+#
+# For now we define these globally to match the current GYP build.
+config("feature_flags") {
+  # Don't use deprecated V8 APIs anywhere.
+  defines = [ "V8_DEPRECATION_WARNINGS" ]
+  if (enable_mdns) {
+    defines += [ "ENABLE_MDNS=1" ]
+  }
+  if (enable_notifications) {
+    defines += [ "ENABLE_NOTIFICATIONS" ]
+  }
+  if (enable_pepper_cdms) {
+    # TODO(brettw) should probably be "=1"
+    defines += [ "ENABLE_PEPPER_CDMS" ]
+  }
+  if (enable_browser_cdms) {
+    # TODO(brettw) should probably be "=1"
+    defines += [ "ENABLE_BROWSER_CDMS" ]
+  }
+  if (enable_plugins) {
+    defines += [ "ENABLE_PLUGINS=1" ]
+  }
+  if (enable_pdf) {
+    defines += [ "ENABLE_PDF=1" ]
+  }
+  if (enable_basic_printing || enable_print_preview) {
+    # Convenience define for ENABLE_BASIC_PRINTING || ENABLE_PRINT_PREVIEW.
+    defines += [ "ENABLE_PRINTING=1" ]
+    if (enable_basic_printing) {
+      # Enable basic printing support and UI.
+      defines += [ "ENABLE_BASIC_PRINTING=1" ]
+    }
+    if (enable_print_preview) {
+      # Enable printing with print preview.
+      # Can be defined without ENABLE_BASIC_PRINTING.
+      defines += [ "ENABLE_PRINT_PREVIEW=1" ]
+    }
+    if ((enable_basic_printing && is_win) || enable_print_preview) {
+      # Windows basic printing or print preview requires pdf enabled.
+      assert(enable_pdf,
+             "Windows basic printing or print preview needs pdf: " +
+                 "set enable_pdf=true.")
+    }
+  }
+  if (enable_spellcheck) {
+    defines += [ "ENABLE_SPELLCHECK=1" ]
+  }
+  if (use_browser_spellchecker) {
+    defines += [ "USE_BROWSER_SPELLCHECKER=1" ]
+  }
+  if (dcheck_always_on) {
+    defines += [ "DCHECK_ALWAYS_ON=1" ]
+  }
+  if (use_udev) {
+    # TODO(brettw) should probably be "=1".
+    defines += [ "USE_UDEV" ]
+  }
+  if (ui_compositor_image_transport) {
+    # TODO(brettw) should probably be "=1".
+    defines += [ "UI_COMPOSITOR_IMAGE_TRANSPORT" ]
+  }
+  if (use_ash) {
+    defines += [ "USE_ASH=1" ]
+  }
+  if (use_aura) {
+    defines += [ "USE_AURA=1" ]
+  }
+  if (use_pango) {
+    defines += [ "USE_PANGO=1" ]
+  }
+  if (use_cairo) {
+    defines += [ "USE_CAIRO=1" ]
+  }
+  if (use_clipboard_aurax11) {
+    defines += [ "USE_CLIPBOARD_AURAX11=1" ]
+  }
+  if (use_default_render_theme) {
+    defines += [ "USE_DEFAULT_RENDER_THEME=1" ]
+  }
+  if (use_glib) {
+    defines += [ "USE_GLIB=1" ]
+  }
+  if (use_openssl_certs) {
+    defines += [ "USE_OPENSSL_CERTS=1" ]
+  }
+  if (use_nss_certs) {
+    defines += [ "USE_NSS_CERTS=1" ]
+  }
+  if (use_ozone) {
+    defines += [ "USE_OZONE=1" ]
+  }
+  if (use_x11) {
+    defines += [ "USE_X11=1" ]
+  }
+  if (use_allocator != "tcmalloc") {
+    defines += [ "NO_TCMALLOC" ]
+  }
+  if (is_asan || is_lsan || is_tsan || is_msan) {
+    defines += [
+      "MEMORY_TOOL_REPLACES_ALLOCATOR",
+      "MEMORY_SANITIZER_INITIAL_SIZE",
+    ]
+  }
+  if (is_asan) {
+    defines += [ "ADDRESS_SANITIZER" ]
+  }
+  if (is_lsan) {
+    defines += [
+      "LEAK_SANITIZER",
+      "WTF_USE_LEAK_SANITIZER=1",
+    ]
+  }
+  if (is_tsan) {
+    defines += [
+      "THREAD_SANITIZER",
+      "DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL=1",
+      "WTF_USE_DYNAMIC_ANNOTATIONS_NOIMPL=1",
+    ]
+  }
+  if (is_msan) {
+    defines += [ "MEMORY_SANITIZER" ]
+  }
+  if (is_ubsan || is_ubsan_vptr || is_ubsan_security) {
+    defines += [ "UNDEFINED_SANITIZER" ]
+  }
+  if (enable_webrtc) {
+    defines += [ "ENABLE_WEBRTC=1" ]
+  }
+  if (!enable_nacl) {
+    defines += [ "DISABLE_NACL" ]
+  }
+  if (enable_extensions) {
+    defines += [ "ENABLE_EXTENSIONS=1" ]
+  }
+  if (enable_task_manager) {
+    defines += [ "ENABLE_TASK_MANAGER=1" ]
+  }
+  if (enable_themes) {
+    defines += [ "ENABLE_THEMES=1" ]
+  }
+  if (enable_captive_portal_detection) {
+    defines += [ "ENABLE_CAPTIVE_PORTAL_DETECTION=1" ]
+  }
+  if (enable_session_service) {
+    defines += [ "ENABLE_SESSION_SERVICE=1" ]
+  }
+  if (enable_rlz) {
+    defines += [ "ENABLE_RLZ" ]
+  }
+  if (enable_plugin_installation) {
+    defines += [ "ENABLE_PLUGIN_INSTALLATION=1" ]
+  }
+  if (enable_app_list) {
+    defines += [ "ENABLE_APP_LIST=1" ]
+  }
+  if (enable_settings_app) {
+    defines += [ "ENABLE_SETTINGS_APP=1" ]
+  }
+  if (enable_supervised_users) {
+    defines += [ "ENABLE_SUPERVISED_USERS=1" ]
+  }
+  if (enable_service_discovery) {
+    defines += [ "ENABLE_SERVICE_DISCOVERY=1" ]
+  }
+  if (enable_image_loader_extension) {
+    defines += [ "IMAGE_LOADER_EXTENSION=1" ]
+  }
+  if (enable_wayland_server) {
+    defines += [ "ENABLE_WAYLAND_SERVER=1" ]
+  }
+  if (enable_wifi_display) {
+    defines += [ "ENABLE_WIFI_DISPLAY=1" ]
+  }
+  if (proprietary_codecs) {
+    defines += [ "USE_PROPRIETARY_CODECS" ]
+  }
+  if (enable_hangout_services_extension) {
+    defines += [ "ENABLE_HANGOUT_SERVICES_EXTENSION=1" ]
+  }
+  if (enable_video_hole) {
+    defines += [ "VIDEO_HOLE=1" ]
+  }
+  if (safe_browsing_mode == 1) {
+    defines += [ "FULL_SAFE_BROWSING" ]
+    defines += [ "SAFE_BROWSING_CSD" ]
+    defines += [ "SAFE_BROWSING_DB_LOCAL" ]
+  } else if (safe_browsing_mode == 2) {
+    defines += [ "SAFE_BROWSING_DB_REMOTE" ]
+  }
+  if (is_official_build) {
+    defines += [ "OFFICIAL_BUILD" ]
+  }
+  if (is_chrome_branded) {
+    defines += [ "GOOGLE_CHROME_BUILD" ]
+  } else {
+    defines += [ "CHROMIUM_BUILD" ]
+  }
+  if (enable_media_router) {
+    defines += [ "ENABLE_MEDIA_ROUTER=1" ]
+  }
+  if (enable_webvr) {
+    defines += [ "ENABLE_WEBVR" ]
+  }
+  if (is_syzyasan) {
+    defines += [
+      "SYZYASAN",
+      "MEMORY_TOOL_REPLACES_ALLOCATOR",
+      "MEMORY_SANITIZER_INITIAL_SIZE",
+    ]
+  }
+  if (!fieldtrial_testing_like_official_build && !is_chrome_branded) {
+    defines += [ "FIELDTRIAL_TESTING_ENABLED" ]
+  }
+}
+
+# Debug/release ----------------------------------------------------------------
+
+config("debug") {
+  defines = [
+    "_DEBUG",
+    "DYNAMIC_ANNOTATIONS_ENABLED=1",
+    "WTF_USE_DYNAMIC_ANNOTATIONS=1",
+  ]
+
+  if (is_nacl) {
+    defines += [ "DYNAMIC_ANNOTATIONS_PREFIX=NACL_" ]
+  }
+
+  if (is_win) {
+    if (!enable_iterator_debugging) {
+      # Iterator debugging is enabled by default by the compiler on debug
+      # builds, and we have to tell it to turn it off.
+      defines += [ "_HAS_ITERATOR_DEBUGGING=0" ]
+    }
+  } else if (is_linux && current_cpu == "x64" && enable_iterator_debugging) {
+    # Enable libstdc++ debugging facilities to help catch problems early, see
+    # http://crbug.com/65151 .
+    # TODO(phajdan.jr): Should we enable this for all of POSIX?
+    defines += [ "_GLIBCXX_DEBUG=1" ]
+  }
+}
+
+config("release") {
+  defines = [ "NDEBUG" ]
+
+  # Sanitizers.
+  if (is_tsan) {
+    defines += [
+      "DYNAMIC_ANNOTATIONS_ENABLED=1",
+      "WTF_USE_DYNAMIC_ANNOTATIONS=1",
+    ]
+  } else {
+    defines += [ "NVALGRIND" ]
+    if (!is_nacl) {
+      # NaCl always enables dynamic annotations. Currently this value is set to
+      # 1 for all .nexes.
+      defines += [ "DYNAMIC_ANNOTATIONS_ENABLED=0" ]
+    }
+  }
+}
+
+# Default libraries ------------------------------------------------------------
+
+# This config defines the default libraries applied to all targets.
+config("default_libs") {
+  if (is_win) {
+    # TODO(brettw) this list of defaults should probably be smaller, and
+    # instead the targets that use the less common ones (e.g. wininet or
+    # winspool) should include those explicitly.
+    libs = [
+      "advapi32.lib",
+      "comdlg32.lib",
+      "dbghelp.lib",
+      "delayimp.lib",
+      "dnsapi.lib",
+      "gdi32.lib",
+      "kernel32.lib",
+      "msimg32.lib",
+      "odbc32.lib",
+      "odbccp32.lib",
+      "ole32.lib",
+      "oleaut32.lib",
+      "psapi.lib",
+      "shell32.lib",
+      "shlwapi.lib",
+      "user32.lib",
+      "usp10.lib",
+      "uuid.lib",
+      "version.lib",
+      "wininet.lib",
+      "winmm.lib",
+      "winspool.lib",
+      "ws2_32.lib",
+
+      # Please don't add more stuff here. We should actually be making this
+      # list smaller, since all common things should be covered. If you need
+      # some extra libraries, please just add a libs = [ "foo.lib" ] to your
+      # target that needs it.
+    ]
+  } else if (is_android) {
+    libs = [
+      "dl",
+      "m",
+    ]
+  } else if (is_mac) {
+    # Targets should choose to explicitly link frameworks they require. Since
+    # linking can have run-time side effects, nothing should be listed here.
+    libs = []
+  } else if (is_ios) {
+    # The libraries listed here will be specified for both the target and the
+    # host. Only the common ones should be listed here.
+    libs = [
+      "CoreFoundation.framework",
+      "CoreGraphics.framework",
+      "CoreText.framework",
+      "Foundation.framework",
+    ]
+  } else if (is_linux) {
+    libs = [
+      "dl",
+      "rt",
+    ]
+  }
+}
+
+# Executable configs -----------------------------------------------------------
+
+# Windows linker setup for EXEs and DLLs.
+if (is_win) {
+  _windows_linker_configs = [
+    "//build/config/win:sdk_link",
+    "//build/config/win:common_linker_setup",
+  ]
+}
+
+# This config defines the configs applied to all executables.
+config("executable_config") {
+  configs = []
+
+  if (is_win) {
+    configs += _windows_linker_configs
+  } else if (is_mac) {
+    configs += [
+      "//build/config/mac:mac_dynamic_flags",
+      "//build/config/mac:mac_executable_flags",
+    ]
+  } else if (is_linux || is_android) {
+    configs += [ "//build/config/gcc:executable_ldconfig" ]
+    if (is_android) {
+      configs += [ "//build/config/android:executable_config" ]
+    } else if (is_chromecast) {
+      configs += [ "//build/config/chromecast:executable_config" ]
+    }
+  }
+}
+
+# Shared library configs -------------------------------------------------------
+
+# This config defines the configs applied to all shared libraries.
+config("shared_library_config") {
+  configs = []
+
+  if (is_win) {
+    configs += _windows_linker_configs
+  } else if (is_mac) {
+    configs += [ "//build/config/mac:mac_dynamic_flags" ]
+  } else if (is_chromecast) {
+    configs += [ "//build/config/chromecast:shared_library_config" ]
+  }
+}
+
+# Add this config to your target to enable precompiled headers.
+#
+# Precompiled headers are done on a per-target basis. If you have just a couple
+# of files, the time it takes to precompile (~2 seconds) can actually be longer
+# than the time saved. On a Z620, a 100 file target compiles about 2 seconds
+# faster with precompiled headers, with greater savings for larger targets.
+#
+# Recommend precompiled headers for targets with more than 50 .cc files.
+config("precompiled_headers") {
+  if (!is_official_build && !use_goma && !disable_precompiled_headers) {
+    if (is_win) {
+      # This is a string rather than a file GN knows about. It has to match
+      # exactly what's in the /FI flag below, and what might appear in the
+      # source code in quotes for an #include directive.
+      precompiled_header = "build/precompile.h"
+
+      # This is a file that GN will compile with the above header. It will be
+      # implicitly added to the sources (potentially multiple times, with one
+      # variant for each language used in the target).
+      precompiled_source = "//build/precompile.cc"
+
+      # Force include the header.
+      cflags = [ "/FI$precompiled_header" ]
+
+      # Disable warning for "this file was empty after preprocessing". This
+      # error is generated only in C mode for ANSI compatibility. It conflicts
+      # with precompiled headers since the source file that's "compiled" for
+      # making the precompiled header is empty.
+      #
+      # This error doesn't happen every time. In VS2013, it seems if the .pch
+      # file doesn't exist, no error will be generated (probably MS tested this
+      # case but forgot the other one?). To reproduce this error, do a build,
+      # then delete the precompile.c.obj file, then build again.
+      cflags_c = [ "/wd4206" ]
+    } else if (is_mac) {
+      precompiled_header = "build/precompile.h"
+      precompiled_source = "//build/precompile.h"
+    }
+  }
+}