build/config/jumbo.gni - chromium/src - Git at Google

 # 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

 declare_args() {
   # If true, use a jumbo build (files compiled together) to speed up
   # compilation.
   use_jumbo_build = false

   # A target to exclude from jumbo builds, for optimal round trip time
   # when frequently changing a single cpp file.
   jumbo_build_excluded = ""

   # How many files to group at most. 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 (much) higher than 100.
   # 100 uses 8% less total CPU than 50 when compiling content and 10%
   # less wall clock when compiling with 4 cores.
   jumbo_file_merge_limit = 100
 }

 # 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
   }
   if (target_name == jumbo_build_excluded) {
     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 = []
   }

   if (invoker_sources != []) {
     gen_target_dir = get_path_info(invoker_sources[0], "gen_dir")
     assert(excluded_sources != [] || true)  # Prevent "unused variable".

     # Find the gen_target_dir directory with shortest path. Short paths
     # are nice in themselves since they mean shorter error messages and
     # fewer bytes to parse, but the currently deployed version of ninja
     # also has a limitation where it only allows 32 path components in
     # Windows.
     # See https://crbug.com/738186 and
     # https://github.com/ninja-build/ninja/issues/1161
     foreach(source_file, invoker_sources) {
       possibly_better_gen_target_dir = get_path_info(gen_target_dir, "dir")
       possibly_better_gen_target_dir_2 =
           get_path_info(possibly_better_gen_target_dir, "dir")
       alt_gen_target_dir = get_path_info(source_file, "gen_dir")
       if (alt_gen_target_dir == possibly_better_gen_target_dir ||
           alt_gen_target_dir == possibly_better_gen_target_dir_2) {
         gen_target_dir = alt_gen_target_dir
       }
     }
   } else {
     gen_target_dir = "<will not be used>"  # Will not result in
                                            # anything used anyway.
   }

   assert(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
     foreach(source_file, invoker_sources) {
       if (get_path_info(source_file, "extension") != "h") {
         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 += jumbo_file_merge_limit
         }
         current_file_index += 1
       }
     }

     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
       assert(current_file_index <= 1)  # Prevent "unused variable"
       assert(next_chunk_start >= 0)  # Prevent "unused variable"
       assert(next_chunk_number <= 2)  # Prevent "unused variable"
     }
   }

   if (use_jumbo_build_for_target) {
     has_c_file = false
     has_objective_c_file = false
     has_S_file = false
     foreach(source_file, invoker_sources) {
       source_ext = get_path_info(source_file, "extension")
       if (source_ext == "c") {
         has_c_file = true
       } else if (source_ext == "mm") {
         has_objective_c_file = true
       } else if (source_ext == "S") {
         has_S_file = true
       }
     }
     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 (has_S_file) {
       jumbo_files += [ "$gen_target_dir/" + target_name + "_jumbo_S.S" ]
     }

     merge_action_name = target_name + "__jumbo_merge"

     # 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(invoker_sources - excluded_sources, gen_target_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
     assert(sources_after_exclusion != [] || true)  # Prevent "unused variable".
   }

   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"

     # Prevent "unused variable" warning.
     assert(!defined(invoker.split_count) || invoker.split_count > 0)
   }

   # 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 = jumbo_files + excluded_sources

       # Need to keep the headers in sources so that dependency checks
       # work.
       foreach(source_file, invoker_sources) {
         if (get_path_info(source_file, "extension") == "h") {
           sources += [ source_file ]
         }
       }
     }
     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 content_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 content_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_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 content_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_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 content_source_set
   # 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
   }
 }
	# 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

	declare_args() {
	# If true, use a jumbo build (files compiled together) to speed up
	# compilation.
	use_jumbo_build = false

	# A target to exclude from jumbo builds, for optimal round trip time
	# when frequently changing a single cpp file.
	jumbo_build_excluded = ""

	# How many files to group at most. 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 (much) higher than 100.
	# 100 uses 8% less total CPU than 50 when compiling content and 10%
	# less wall clock when compiling with 4 cores.
	jumbo_file_merge_limit = 100
	}

	# 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
	}
	if (target_name == jumbo_build_excluded) {
	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 = []
	}

	if (invoker_sources != []) {
	gen_target_dir = get_path_info(invoker_sources[0], "gen_dir")
	assert(excluded_sources != [] \|\| true) # Prevent "unused variable".

	# Find the gen_target_dir directory with shortest path. Short paths
	# are nice in themselves since they mean shorter error messages and
	# fewer bytes to parse, but the currently deployed version of ninja
	# also has a limitation where it only allows 32 path components in
	# Windows.
	# See https://crbug.com/738186 and
	# https://github.com/ninja-build/ninja/issues/1161
	foreach(source_file, invoker_sources) {
	possibly_better_gen_target_dir = get_path_info(gen_target_dir, "dir")
	possibly_better_gen_target_dir_2 =
	get_path_info(possibly_better_gen_target_dir, "dir")
	alt_gen_target_dir = get_path_info(source_file, "gen_dir")
	if (alt_gen_target_dir == possibly_better_gen_target_dir \|\|
	alt_gen_target_dir == possibly_better_gen_target_dir_2) {
	gen_target_dir = alt_gen_target_dir
	}
	}
	} else {
	gen_target_dir = "<will not be used>" # Will not result in
	# anything used anyway.
	}

	assert(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
	foreach(source_file, invoker_sources) {
	if (get_path_info(source_file, "extension") != "h") {
	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 += jumbo_file_merge_limit
	}
	current_file_index += 1
	}
	}

	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
	assert(current_file_index <= 1) # Prevent "unused variable"
	assert(next_chunk_start >= 0) # Prevent "unused variable"
	assert(next_chunk_number <= 2) # Prevent "unused variable"
	}
	}

	if (use_jumbo_build_for_target) {
	has_c_file = false
	has_objective_c_file = false
	has_S_file = false
	foreach(source_file, invoker_sources) {
	source_ext = get_path_info(source_file, "extension")
	if (source_ext == "c") {
	has_c_file = true
	} else if (source_ext == "mm") {
	has_objective_c_file = true
	} else if (source_ext == "S") {
	has_S_file = true
	}
	}
	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 (has_S_file) {
	jumbo_files += [ "$gen_target_dir/" + target_name + "_jumbo_S.S" ]
	}

	merge_action_name = target_name + "__jumbo_merge"

	# 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(invoker_sources - excluded_sources, gen_target_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
	assert(sources_after_exclusion != [] \|\| true) # Prevent "unused variable".
	}

	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"

	# Prevent "unused variable" warning.
	assert(!defined(invoker.split_count) \|\| invoker.split_count > 0)
	}

	# 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 = jumbo_files + excluded_sources

	# Need to keep the headers in sources so that dependency checks
	# work.
	foreach(source_file, invoker_sources) {
	if (get_path_info(source_file, "extension") == "h") {
	sources += [ source_file ]
	}
	}
	}
	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 content_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 content_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_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 content_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_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 content_source_set
	# 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
	}
	}