ceph/src/boost/tools/build/src/tools/features/lto-feature.jam

   1 # Copyright 2019 Dmitry Arkhipov
   2 # Distributed under the Boost Software License, Version 1.0.
   3 # (See accompanying file LICENSE.txt or copy at
   4 # https://www.bfgroup.xyz/b2/LICENSE.txt)
   5
   6 import feature ;
   7
   8 #| tag::doc[]
   9
  10 [[bbv2.builtin.features.lto]]`lto`::
  11 *Allowed values:* `on`.
  12 +
  13 Enables link time optimizations (also known as interprocedural optimizations or
  14 whole-program optimizations). Currently supported toolsets are <<GNU {CPP}>>,
  15 clang and <<Microsoft Visual {CPP}>>. The feature is optional.
  16
  17 |# # end::doc[]
  18
  19 feature.feature lto
  20     : on
  21     : optional propagated ;
  22
  23 #| tag::doc[]
  24
  25 [[bbv2.builtin.features.lto-mode]]`lto-mode`::
  26 *Subfeature of* `lto`
  27 +
  28 *Allowed values:* `full`, `thin`, `fat`.
  29 +
  30 Specifies the type of LTO to use.
  31 +
  32 `full`::: Use the monolithic LTO: on linking all input is merged into a single
  33   module.
  34 `thin`::: Use clang's ThinLTO: each compiled file contains a summary of the
  35   module, these summaries are merged into a single index. This allows to avoid
  36   merging all modules together, which greatly reduces linking time.
  37 `fat`::: Produce gcc's fat LTO objects: compiled files contain both the
  38   intermidiate language suitable for LTO and object code suitable for regular
  39   linking.
  40
  41 |# # end::doc[]
  42
  43 feature.subfeature lto
  44     : mode
  45     : full thin fat
  46     : propagated ;