blob: 572762b04f8a3b7600cad9502c0bba83b4d97452 [file] [log] [blame]
# Copyright 2017 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/split_static_library.gni") # When someone uses that target_type
import("//build/toolchain/goma.gni")
declare_args() {
# If true, use a jumbo build (files compiled together) to speed up
# compilation.
use_jumbo_build = false
# A list of build targets to exclude from jumbo builds, for optimal
# round trip time when frequently changing a set of cpp files. The
# targets can be just the short name (in which case it matches any
# target with that name), a directory prefixed with the root
# specifier //, or a full build target label.
#
# Example:
# These would all exclude the "browser" target in a file
# content/browser/BUILD.gn, and potentially more.
#
# jumbo_build_excluded = [ "browser" ]
# jumbo_build_excluded = [ "//content/browser" ]
# jumbo_build_excluded = [ "//content/browser:browser" ]
jumbo_build_excluded = []
# How many files to group on average. Smaller numbers give more
# parallellism, higher numbers give less total CPU usage. Higher
# numbers also give longer single-file recompilation times.
#
# Recommendations:
# Higher numbers than 100 does not reduce wall clock compile times
# even for 4 cores or less so no reason to go higher than 100.
# Going from 50 to 100 with a 4 core CPU saves about 3% CPU time and
# 3% wall clock time in a tree with blink, v8 and content
# jumbofied. At the same time it increases the compile time for the
# largest jumbo chunks by 10-20% and reduces the chance to use all
# available CPU cores. So set the default to 50 to balance between
# high and low-core build performance. -1 means do the default which
# varies depending on whether goma is enabled.
jumbo_file_merge_limit = -1
}
# Normal builds benefit from lots of jumbification
jumbo_file_merge_default = 50
# Goma builds benefit from more parallelism
jumbo_file_merge_goma = 8
# Use one of the targets jumbo_source_set, jumbo_static_library,
# jumbo_split_static_library or jumbo_component to generate a target
# which merges sources if possible to compile much faster.
#
# Special values.
#
# target_type
# The kind of target to build. For example the string
# "static_library".
#
# always_build_jumbo
# If set and set to true, then use jumbo compile even when it is
# globally disabled. Otherwise it has no effect.
#
# never_build_jumbo
# If set and set to true, then do not jumbo compile even if it is
# globally enabled. Otherwise it has no effect.
#
# jumbo_excluded_sources
# If set to a list of files, those files will not be merged with
# the rest. This can be necessary if merging the files causes
# compilation issues and fixing the issues is impractical.
template("internal_jumbo_target") {
use_jumbo_build_for_target = use_jumbo_build
if (defined(invoker.always_build_jumbo) && invoker.always_build_jumbo) {
use_jumbo_build_for_target = true
}
if (defined(invoker.never_build_jumbo) && invoker.never_build_jumbo) {
use_jumbo_build_for_target = false
}
foreach(excluded_target, jumbo_build_excluded) {
if (excluded_target == target_name ||
excluded_target == get_label_info(":" + target_name, "dir") ||
excluded_target ==
get_label_info(":" + target_name, "label_no_toolchain")) {
use_jumbo_build_for_target = false
}
}
excluded_sources = []
if (defined(invoker.jumbo_excluded_sources)) {
excluded_sources = invoker.jumbo_excluded_sources
}
if (defined(invoker.sources)) {
invoker_sources = invoker.sources
} else {
invoker_sources = []
}
gen_target_dir = invoker.target_gen_dir
not_needed([ "gen_target_dir" ]) # Prevent "unused variable".
if (use_jumbo_build_for_target) {
jumbo_files = []
# Split the sources list into chunks that are not excessively large
current_file_index = 0
next_chunk_start = 0
next_chunk_number = 1
merge_limit = jumbo_file_merge_limit
if (merge_limit == -1) {
if (use_goma) {
merge_limit = jumbo_file_merge_goma
} else {
merge_limit = jumbo_file_merge_default
}
}
has_c_file = false
has_objective_c_file = false
sources_in_jumbo_files = []
assert(merge_limit > 0)
foreach(source_file, invoker_sources) {
source_ext = get_path_info(source_file, "extension")
is_source_file = true
if (source_ext == "c") {
has_c_file = true
} else if (source_ext == "mm") {
has_objective_c_file = true
} else if (source_ext == "cc" || source_ext == "cpp") {
if (current_file_index == next_chunk_start) {
jumbo_files += [ "$gen_target_dir/" + target_name + "_jumbo_" +
next_chunk_number + ".cc" ]
next_chunk_number += 1
next_chunk_start += merge_limit
}
current_file_index += 1
} else {
is_source_file = false
}
if (is_source_file) {
sources_in_jumbo_files += [ source_file ]
}
}
if (jumbo_files == [] || current_file_index == 1) {
# Empty sources list or a sources list with only header files or
# at most one non-header file.
use_jumbo_build_for_target = false
not_needed([
"sources_in_jumbo_files",
"current_file_index",
"next_chunk_start",
"next_chunk_number",
])
}
if (has_c_file) {
jumbo_files += [ "$gen_target_dir/" + target_name + "_jumbo_c.c" ]
}
if (has_objective_c_file) {
jumbo_files += [ "$gen_target_dir/" + target_name + "_jumbo_mm.mm" ]
}
}
if (use_jumbo_build_for_target) {
merge_action_name = target_name + "__jumbo_merge"
sources_in_jumbo_files -= excluded_sources
# Create an action that calls a script that merges all the source files.
action(merge_action_name) {
script = "//build/config/merge_for_jumbo.py"
response_file_contents =
rebase_path(sources_in_jumbo_files, root_build_dir)
outputs = jumbo_files
args = [ "--outputs" ] + rebase_path(outputs, root_build_dir) +
[ "--file-list={{response_file_name}}" ]
}
} else {
# If the list subtraction triggers a gn error,
# jumbo_excluded_sources lists a file that is not in sources.
sources_after_exclusion = invoker_sources - excluded_sources
not_needed([ "sources_after_exclusion" ])
}
target_type = invoker.target_type
if (use_jumbo_build_for_target && target_type == "split_static_library") {
# Meaningless and also impossible if split_count > len(jumbo_files)
target_type = "static_library"
not_needed(invoker, [ "split_count" ])
}
# Perform the actual operation, either on the original sources or
# the sources post-jumbo merging.
target(target_type, target_name) {
deps = []
if (defined(invoker.deps)) {
deps += invoker.deps
}
# Take everything else not handled above from the invoker.
variables_to_not_forward = [ "deps" ]
if (use_jumbo_build_for_target) {
deps += [ ":" + merge_action_name ]
variables_to_not_forward += [ "sources" ]
assert(jumbo_files != [])
set_sources_assignment_filter([]) # Prefiltered.
sources = invoker_sources - sources_in_jumbo_files + jumbo_files
# Change include_dirs to make sure that the jumbo file can find its
# #included files.
variables_to_not_forward += [ "include_dirs" ]
include_dirs = []
if (defined(invoker.include_dirs)) {
include_dirs = invoker.include_dirs
}
include_dirs += [ root_build_dir ]
# For the "gn analyze" step to work, gn needs to know about the
# original source files. They can't be in |sources| because then
# they will be compiled, so they have to be somewhere else where
# gn analyze looks. Let's go with the |data| variable.
variables_to_not_forward += [ "data" ]
data = []
if (defined(invoker.data)) {
data += invoker.data
}
data += invoker_sources - excluded_sources
}
forward_variables_from(invoker, "*", variables_to_not_forward)
}
}
# See documentation above by "internal_jumbo_target".
template("jumbo_source_set") {
internal_jumbo_target(target_name) {
target_type = "source_set"
forward_variables_from(invoker, "*")
}
}
set_defaults("jumbo_source_set") {
# This sets the default list of configs when the jumbo_source_set target
# is defined. The default_compiler_configs comes from BUILDCONFIG.gn and
# is the list normally applied to static libraries and source sets.
configs = default_compiler_configs
}
# See documentation above by "internal_jumbo_target".
template("jumbo_static_library") {
internal_jumbo_target(target_name) {
target_type = "static_library"
forward_variables_from(invoker, "*")
}
}
set_defaults("jumbo_static_library") {
# This sets the default list of configs when the jumbo_static_library target
# is defined. The default_compiler_configs comes from BUILDCONFIG.gn and
# is the list normally applied to static libraries and source sets.
configs = default_compiler_configs
}
# See documentation above by "internal_jumbo_target".
template("jumbo_split_static_library") {
internal_jumbo_target(target_name) {
target_type = "split_static_library"
forward_variables_from(invoker, "*")
}
}
set_defaults("jumbo_split_static_library") {
# This sets the default list of configs when the
# jumbo_split_static_library target is defined. The
# default_compiler_configs comes from BUILDCONFIG.gn and is the list
# normally applied to static libraries and source sets.
configs = default_compiler_configs
}
# See documentation above by "internal_jumbo_target".
template("jumbo_component") {
internal_jumbo_target(target_name) {
target_type = "component"
forward_variables_from(invoker, "*")
}
}
set_defaults("jumbo_component") {
# This sets the default list of configs when the jumbo_component
# target is defined. This code is a clone of set_defaults for the
# ordinary "component" template.
if (is_component_build) {
configs = default_shared_library_configs
if (is_android) {
configs -= [ "//build/config/android:hide_all_but_jni_onload" ]
}
} else {
configs = default_compiler_configs
}
}