build/split_static_library.gni

   1 # Copyright 2016 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import("//build/config/compiler/compiler.gni")
   6
   7 template("split_static_library") {
   8   assert(defined(invoker.split_count),
   9          "Must define split_count for split_static_library")
  10
  11   # In many conditions the number of inputs will be 1 (because the
  12   # count will be conditional on platform or configuration) and for
  13   # some build configurations it's unnecessary to split libraries
  14   # since the tooling will never create files of a problematic size.
  15   if (invoker.split_count == 1 || use_lld) {
  16     static_library(target_name) {
  17       forward_variables_from(invoker, "*")
  18     }
  19   } else {
  20     group_name = target_name
  21
  22     generated_static_libraries = []
  23     current_library_index = 0
  24     foreach(current_sources, split_list(invoker.sources, invoker.split_count)) {
  25       current_name = "${target_name}_$current_library_index"
  26       assert(
  27           current_sources != [],
  28           "Your values for splitting a static library generate one that has no sources.")
  29       generated_static_libraries += [ ":$current_name" ]
  30
  31       static_library(current_name) {
  32         # Generated static library shard gets everything but sources (which
  33         # we're redefining) and visibility (which is set to be the group
  34         # below).
  35         forward_variables_from(invoker,
  36                                "*",
  37                                [
  38                                  "check_includes",
  39                                  "sources",
  40                                  "visibility",
  41                                ])
  42         sources = current_sources
  43         visibility = [ ":$group_name" ]
  44
  45         # When splitting a target's sources up into a series of static
  46         # libraries, those targets will naturally include headers from each
  47         # other arbitrarily. We could theoretically generate a web of
  48         # dependencies and allow_circular_includes_from between all pairs of
  49         # targets, but that's very cumbersome. Typical usage in Chrome is that
  50         # only official Windows builds use split static libraries due to the
  51         # Visual Studio size limits, and this means we'll still get header
  52         # checking coverage for the other configurations.
  53         check_includes = false
  54
  55         # Uniquify the output name if one is specified.
  56         if (defined(invoker.output_name)) {
  57           output_name = "${invoker.output_name}_$current_library_index"
  58         }
  59       }
  60
  61       current_library_index = current_library_index + 1
  62     }
  63
  64     group(group_name) {
  65       public_deps = generated_static_libraries
  66       forward_variables_from(invoker,
  67                              [
  68                                "testonly",
  69                                "visibility",
  70                              ])
  71     }
  72   }
  73 }
  74
  75 if (!use_efl) {
  76   set_defaults("split_static_library") {
  77     configs = default_compiler_configs
  78   }
  79 }