solenv/gbuild/PrecompiledHeaders.mk

   1 # -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
   2 #
   3 # This file is part of the LibreOffice project.
   4 #
   5 # This Source Code Form is subject to the terms of the Mozilla Public
   6 # License, v. 2.0. If a copy of the MPL was not distributed with this
   7 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8 #
   9 # This file incorporates work covered by the following license notice:
  10 #
  11 #   Licensed to the Apache Software Foundation (ASF) under one or more
  12 #   contributor license agreements. See the NOTICE file distributed
  13 #   with this work for additional information regarding copyright
  14 #   ownership. The ASF licenses this file to you under the Apache
  15 #   License, Version 2.0 (the "License"); you may not use this file
  16 #   except in compliance with the License. You may obtain a copy of
  17 #   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18 #
  19
  20
  21 # PrecompiledHeader class
  22
  23 # Use different PCH file depending on whether we use debugging symbols.
  24 gb_PrecompiledHeader__get_debugdir = $(if $(call gb_target_symbols_enabled,$(1)),debug,nodebug)
  25
  26 # $(call gb_PrecompiledHeader_generate_timestamp_rule,linktargetmakefilename)
  27 define gb_PrecompiledHeader_generate_timestamp_rule
  28 $(call gb_LinkTarget_get_pch_timestamp,$(1)) :
  29         mkdir -p $$(dir $$@) && touch $$@
  30
  31 endef
  32
  33 ifneq ($(gb_ENABLE_PCH),)
  34
  35 # IMPORTANT: Since these defines get expanded, every $ needs to be doubled to $$, except
  36 # for $(1)'s and things that are constant.
  37 # The defines are needed to get the right version of gb_PrecompiledHeader__get_debugdir.
  38
  39 # all cxxflags to use for compilation
  40 gb_PrecompiledHeader_cxxflags_includes := $$(PCH_DEFS) $$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS)
  41 # flags to save to the .flags file to check if they are the same as last time
  42 # (note: the leading space in sed is important, to remove the option and its separating space)
  43 gb_PrecompiledHeader_flags_for_flags_file := $$(sort $(gb_PrecompiledHeader_cxxflags_includes)) \
  44     $(if $(gb_PrecompiledHeader_ignore_flags_for_flags_file),| sed 's/ $(gb_PrecompiledHeader_ignore_flags_for_flags_file)//')
  45
  46 # $(call gb_PrecompiledHeader_generate_rules,pchtarget,linktarget,linktargetmakefilename,pchcxxfile,compiler)
  47 define gb_PrecompiledHeader_generate_rules
  48
  49 $(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)) :
  50         $$(call gb_Helper_abbreviate_dirs,\
  51                 mkdir -p $$(dir $$@) && \
  52                 echo "$$(call gb_PrecompiledHeader_get_target,$(1),$(3)) : $$(gb_Helper_PHONY)" > $$@)
  53
  54 # keep the flags the PCH was built with in a separate file, update the file if and only if the flags
  55 # change, and make the PCH depend on it => the PCH will be rebuilt on any flags change
  56 .PHONY: force
  57 $(call gb_PrecompiledHeader_get_flags_file,$(1),$(3)) : force
  58         $$(call gb_Helper_abbreviate_dirs,\
  59                 mkdir -p $$(dir $$@) && \
  60                 echo $(gb_PrecompiledHeader_flags_for_flags_file) | cmp -s - $$@ \
  61                 || echo $(gb_PrecompiledHeader_flags_for_flags_file) > $$@)
  62
  63 # despite this being only one .d file, need to run concat-deps on it to
  64 # re-write external headers from UnpackedTarball
  65 $(call gb_PrecompiledHeader_get_target,$(1),$(3)) :
  66         test "$$(PCH_LINKTARGETMAKEFILENAME)" = "$(3)" \
  67                  || ( echo "Error, PCH $(1) built by $$(PCH_LINKTARGETMAKEFILENAME) instead of $(3)" >&2; exit 1)
  68         rm -f $$@
  69         $$(call gb_PrecompiledHeader__command,$$@,$(1),$$<,$(gb_PrecompiledHeader_cxxflags_includes),$$(INCLUDE),$(3),$(5))
  70         $$(call gb_PrecompiledHeader__sum_command,$$@,$(1),$$<,$(gb_PrecompiledHeader_cxxflags_includes),$$(INCLUDE),$(3),$(5))
  71 ifeq ($(gb_FULLDEPS),$(true))
  72         $$(call gb_Helper_abbreviate_dirs,\
  73                 RESPONSEFILE=$$(call gb_var2file,$$(shell $$(gb_MKTEMP)),$$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(3))) && \
  74                 SYSTEM_BOOST="$(SYSTEM_BOOST)" $$(call gb_Executable_get_command,concat-deps) $$$${RESPONSEFILE} \
  75                         > $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)) && \
  76                 rm -f $$$${RESPONSEFILE} $$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(3)))
  77 endif
  78
  79 $(call gb_PrecompiledHeader_get_for_reuse_target,$(1),$(3)) : $(call gb_LinkTarget_get_target,$(2))
  80         $$(call gb_PrecompiledHeader__create_reuse_files,$(2),$(1),$(3))
  81         mkdir -p $$(dir $$@) && touch $$@
  82
  83 .PHONY : $(call gb_PrecompiledHeader_get_clean_target,$(1))
  84 $(call gb_PrecompiledHeader_get_clean_target,$(1)) :
  85         $$(call gb_Output_announce,$(1),$(false),PCH,1)
  86         -$$(call gb_Helper_abbreviate_dirs,\
  87                 rm -f $$(call gb_PrecompiledHeader_get_target,$(1),$(3)) \
  88                         $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).obj \
  89                         $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).pdb \
  90                         $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).sum \
  91                         $$(call gb_PrecompiledHeader_get_flags_file,$(1),$(3)) \
  92                         $$(call gb_PrecompiledHeader_get_for_reuse_target,$(1),$(3)) \
  93                         $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)))
  94
  95 endef
  96
  97 # $(call gb_PrecompiledHeader_check_flags,linktargetmakefilename,pchcxxfile,pchfile,flags)
  98 # When creating a PCH, the PCH's CXXFLAGS are saved to a matching .flags file. When reusing the PCH
  99 # from another linktarget, use the file to check that the linktarget uses the same CXXFLAGS as the PCH.
 100 # This complements the check in gb_CxxObject__set_pchflags.
 101 define gb_PrecompiledHeader_check_flags
 102 $$(call gb_Helper_abbreviate_dirs,\
 103         $$(if $$(strip $$(call gb_PrecompiledHeader_check_flags_internal,$$(shell cat $(4)),$(5),$(2))),false,true) || ( \
 104                 echo Error reusing $(2) by $(1). >&2 && \
 105                 echo -n " precompiled header flags : ">&2 && \
 106                 cat $(4) >&2 && \
 107                 echo    "            object flags  : "$$(sort $(5)) >&2 && \
 108                 echo    " reason : $$(call gb_PrecompiledHeader_check_flags_internal,$$(shell cat $(4)),$(5),$(2))" >&2 && \
 109                 echo Incorrect precompiled header setup or internal gbuild error. >&2 ; \
 110                 exit 1) \
 111 )
 112
 113 endef
 114
 115 # When trying to reuse one PCH between multiple linktargets, there is a problem that we have
 116 # various defines that cause mismatch in the check above, but these defines actually should not affect the PCH.
 117 # Specifically, there are 3 kinds:
 118 # - -DXXX_DLLIMPLEMENTATION - they are used only in our headers, should not affect system headers.
 119 # - -DSYSTEM_XXX - they are used only by our code (if at all), should not affect system headers
 120 # - various LO configuration defines - they again should only be used by our code and not system headers
 121 # Technically, different compilers handle additional defines like this:
 122 # - GCC
 123 #   * It is explicitly allowed to have different macros, as long as they do not affect the PCH.
 124 #   * With -Winvalid-pch GCC will even warn if there is a change in a macro affecting the PCH.
 125 #   * https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html
 126 # - Clang
 127 #   * I could not find an official statement on what happens if definitions are different.
 128 #   * In practice a conflict does not seem to be detected, but the PCH and all the code in it
 129 #     acts according to the settings it was built with. Using a PCH and adding more defines
 130 #     seems to be functionally equivalent to creating the definitions only after the PCH inclusion.
 131 #   * As a side-effect, macros defined on the command line not present in the PCH suddenly
 132 #     trigger the -Wunused-macros warning. See bottom of pch/inc/clangfix.hxx .
 133 # - MSVC
 134 #   * MSVC explicitly states that the definitions must be the same, but they are not checked,
 135 #     and "unpredictable results can occur" if files depend on them.
 136 #   * In practice the situation seems to be the same as with Clang, the PCH and the code from it
 137 #     act according to the settings it was built with.
 138 #   * https://docs.microsoft.com/en-us/cpp/build/creating-precompiled-header-files
 139 # So while this is officially tricky, in practice it seems to work to allow PCH reuse if the linktarget
 140 # has more defines than the PCH was built with, as long as the defines do not affect the PCH.
 141 gb_PrecompiledHeader_ignore_flags_system := \
 142 -DSAX_DLLIMPLEMENTATION \
 143 -DSCQAHELPER_DLLIMPLEMENTATION \
 144 -DVCLPLUG_WIN_IMPLEMENTATION \
 145 -DVCLPLUG_GEN_IMPLEMENTATION \
 146 -DSYSTEM_EXPAT \
 147 -DSYSTEM_LIBXML \
 148 -DSYSTEM_ZLIB \
 149 -DSYSTEM_NSS \
 150 -DHAVE_VALGRIND_HEADERS \
 151 -DUSE_RANDR \
 152 -DUSE_XINERAMA_XORG \
 153 -DDISABLE_CVE_TESTS \
 154 -DCPPUNIT_PLUGIN_EXPORT='extern "C" SAL_DLLPUBLIC_EXPORT' \
 155 -DOOO_DLLIMPLEMENTATION_TEST \
 156 -DSK_USER_CONFIG_HEADER=% \
 157 -DSKIA_DLL \
 158 -DGLM_FORCE_CTOR_INIT \
 159 -DVCL_INTERNALS \
 160 -DZLIB_CONST \
 161 $(gb_CXXFLAGS_include)$(SRCDIR)/pch/inc/clangfix.hxx \
 162 $(gb_CXXFLAGS_no_pch_warnings) \
 163 $(gb_PrecompiledHeader_ignore_flags_for_flags_file) \
 164
 165 # Probably also update pch/inc/clangfix.hxx if you extend the list.
 166
 167 # $(call gb_PrecompiledHeader_check_flags_internal,pchfileflags,flags,pchcxxfile)
 168 # Check if two sets of flags are compatible, allowing reuse of the PCH. Flags are compatible if
 169 # - they are the same
 170 # - the PCH is precompiled_system and the linktarget has additional defines listed above
 171 define gb_PrecompiledHeader_check_flags_internal
 172 $(if $(filter-out $(2),$(1)),$(filter-out $(2),$(1)), \
 173         $(if $(filter-out $(1),$(2)),\
 174                 $(if $(filter-out precompiled_system,$(notdir $(3))),$(filter-out $(1),$(2)), \
 175                         $(foreach flag,$(filter-out $(1),$(2)),$(filter-out $(gb_PrecompiledHeader_ignore_flags_system),$(flag))) \
 176                 ) \
 177         ,) \
 178 )
 179 endef
 180
 181 endif
 182
 183 # vim: set noet sw=4: