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+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# This file incorporates work covered by the following license notice:
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed
+# with this work for additional information regarding copyright
+# ownership. The ASF licenses this file to you under the Apache
+# License, Version 2.0 (the "License"); you may not use this file
+# except in compliance with the License. You may obtain a copy of
+# the License at http://www.apache.org/licenses/LICENSE-2.0 .
+#
+
+
+# PrecompiledHeader class
+
+# Use different PCH file depending on whether we use debugging symbols.
+gb_PrecompiledHeader__get_debugdir = $(if $(call gb_target_symbols_enabled,$(1)),debug,nodebug)
+
+# $(call gb_PrecompiledHeader_generate_timestamp_rule,linktargetmakefilename)
+define gb_PrecompiledHeader_generate_timestamp_rule
+$(call gb_LinkTarget_get_pch_timestamp,$(1)) :
+ mkdir -p $$(dir $$@) && touch $$@
+
+endef
+
+ifneq ($(gb_ENABLE_PCH),)
+
+# IMPORTANT: Since these defines get expanded, every $ needs to be doubled to $$, except
+# for $(1)'s and things that are constant.
+# The defines are needed to get the right version of gb_PrecompiledHeader__get_debugdir.
+
+# all cxxflags to use for compilation
+gb_PrecompiledHeader_cxxflags_includes := $$(PCH_DEFS) $$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS)
+# flags to save to the .flags file to check if they are the same as last time
+# (note: the leading space in sed is important, to remove the option and its separating space)
+gb_PrecompiledHeader_flags_for_flags_file := $$(sort $(gb_PrecompiledHeader_cxxflags_includes)) \
+ $(if $(gb_PrecompiledHeader_ignore_flags_for_flags_file),| sed 's/ $(gb_PrecompiledHeader_ignore_flags_for_flags_file)//')
+
+# $(call gb_PrecompiledHeader_generate_rules,pchtarget,linktarget,linktargetmakefilename,pchcxxfile,compiler)
+define gb_PrecompiledHeader_generate_rules
+
+$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)) :
+ $$(call gb_Helper_abbreviate_dirs,\
+ mkdir -p $$(dir $$@) && \
+ echo "$$(call gb_PrecompiledHeader_get_target,$(1),$(3)) : $$(gb_Helper_PHONY)" > $$@)
+
+# keep the flags the PCH was built with in a separate file, update the file if and only if the flags
+# change, and make the PCH depend on it => the PCH will be rebuilt on any flags change
+.PHONY: force
+$(call gb_PrecompiledHeader_get_flags_file,$(1),$(3)) : force
+ $$(call gb_Helper_abbreviate_dirs,\
+ mkdir -p $$(dir $$@) && \
+ echo $(gb_PrecompiledHeader_flags_for_flags_file) | cmp -s - $$@ \
+ || echo $(gb_PrecompiledHeader_flags_for_flags_file) > $$@)
+
+# despite this being only one .d file, need to run concat-deps on it to
+# re-write external headers from UnpackedTarball
+$(call gb_PrecompiledHeader_get_target,$(1),$(3)) :
+ test "$$(PCH_LINKTARGETMAKEFILENAME)" = "$(3)" \
+ || ( echo "Error, PCH $(1) built by $$(PCH_LINKTARGETMAKEFILENAME) instead of $(3)" >&2; exit 1)
+ rm -f $$@
+ $$(call gb_PrecompiledHeader__command,$$@,$(1),$$<,$(gb_PrecompiledHeader_cxxflags_includes),$$(INCLUDE),$(3),$(5))
+ $$(call gb_PrecompiledHeader__sum_command,$$@,$(1),$$<,$(gb_PrecompiledHeader_cxxflags_includes),$$(INCLUDE),$(3),$(5))
+ifeq ($(gb_FULLDEPS),$(true))
+ $$(call gb_Helper_abbreviate_dirs,\
+ RESPONSEFILE=$$(call gb_var2file,$$(shell $$(gb_MKTEMP)),$$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(3))) && \
+ SYSTEM_BOOST="$(SYSTEM_BOOST)" $$(call gb_Executable_get_command,concat-deps) $$$${RESPONSEFILE} \
+ > $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)) && \
+ rm -f $$$${RESPONSEFILE} $$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(3)))
+endif
+
+$(call gb_PrecompiledHeader_get_for_reuse_target,$(1),$(3)) : $(call gb_LinkTarget_get_target,$(2))
+ $$(call gb_PrecompiledHeader__create_reuse_files,$(2),$(1),$(3))
+ mkdir -p $$(dir $$@) && touch $$@
+
+.PHONY : $(call gb_PrecompiledHeader_get_clean_target,$(1))
+$(call gb_PrecompiledHeader_get_clean_target,$(1)) :
+ $$(call gb_Output_announce,$(1),$(false),PCH,1)
+ -$$(call gb_Helper_abbreviate_dirs,\
+ rm -f $$(call gb_PrecompiledHeader_get_target,$(1),$(3)) \
+ $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).obj \
+ $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).pdb \
+ $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).sum \
+ $$(call gb_PrecompiledHeader_get_flags_file,$(1),$(3)) \
+ $$(call gb_PrecompiledHeader_get_for_reuse_target,$(1),$(3)) \
+ $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)))
+
+endef
+
+# $(call gb_PrecompiledHeader_check_flags,linktargetmakefilename,pchcxxfile,pchfile,flags)
+# When creating a PCH, the PCH's CXXFLAGS are saved to a matching .flags file. When reusing the PCH
+# from another linktarget, use the file to check that the linktarget uses the same CXXFLAGS as the PCH.
+# This complements the check in gb_CxxObject__set_pchflags.
+define gb_PrecompiledHeader_check_flags
+$$(call gb_Helper_abbreviate_dirs,\
+ $$(if $$(strip $$(call gb_PrecompiledHeader_check_flags_internal,$$(shell cat $(4)),$(5),$(2))),false,true) || ( \
+ echo Error reusing $(2) by $(1). >&2 && \
+ echo -n " precompiled header flags : ">&2 && \
+ cat $(4) >&2 && \
+ echo " object flags : "$$(sort $(5)) >&2 && \
+ echo " reason : $$(call gb_PrecompiledHeader_check_flags_internal,$$(shell cat $(4)),$(5),$(2))" >&2 && \
+ echo Incorrect precompiled header setup or internal gbuild error. >&2 ; \
+ exit 1) \
+)
+
+endef
+
+# When trying to reuse one PCH between multiple linktargets, there is a problem that we have
+# various defines that cause mismatch in the check above, but these defines actually should not affect the PCH.
+# Specifically, there are 3 kinds:
+# - -DXXX_DLLIMPLEMENTATION - they are used only in our headers, should not affect system headers.
+# - -DSYSTEM_XXX - they are used only by our code (if at all), should not affect system headers
+# - various LO configuration defines - they again should only be used by our code and not system headers
+# Technically, different compilers handle additional defines like this:
+# - GCC
+# * It is explicitly allowed to have different macros, as long as they do not affect the PCH.
+# * With -Winvalid-pch GCC will even warn if there is a change in a macro affecting the PCH.
+# * https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html
+# - Clang
+# * I could not find an official statement on what happens if definitions are different.
+# * In practice a conflict does not seem to be detected, but the PCH and all the code in it
+# acts according to the settings it was built with. Using a PCH and adding more defines
+# seems to be functionally equivalent to creating the definitions only after the PCH inclusion.
+# * As a side-effect, macros defined on the command line not present in the PCH suddenly
+# trigger the -Wunused-macros warning. See bottom of pch/inc/clangfix.hxx .
+# - MSVC
+# * MSVC explicitly states that the definitions must be the same, but they are not checked,
+# and "unpredictable results can occur" if files depend on them.
+# * In practice the situation seems to be the same as with Clang, the PCH and the code from it
+# act according to the settings it was built with.
+# * https://docs.microsoft.com/en-us/cpp/build/creating-precompiled-header-files
+# So while this is officially tricky, in practice it seems to work to allow PCH reuse if the linktarget
+# has more defines than the PCH was built with, as long as the defines do not affect the PCH.
+gb_PrecompiledHeader_ignore_flags_system := \
+-DSAX_DLLIMPLEMENTATION \
+-DSCQAHELPER_DLLIMPLEMENTATION \
+-DVCLPLUG_WIN_IMPLEMENTATION \
+-DVCLPLUG_GEN_IMPLEMENTATION \
+-DSYSTEM_EXPAT \
+-DSYSTEM_LIBXML \
+-DSYSTEM_ZLIB \
+-DSYSTEM_NSS \
+-DHAVE_VALGRIND_HEADERS \
+-DUSE_RANDR \
+-DDISABLE_CVE_TESTS \
+-DCPPUNIT_PLUGIN_EXPORT='extern "C" SAL_DLLPUBLIC_EXPORT' \
+-DOOO_DLLIMPLEMENTATION_TEST \
+-DSK_USER_CONFIG_HEADER=% \
+-DSKIA_DLL \
+-DGLM_FORCE_CTOR_INIT \
+-DVCL_INTERNALS \
+-DZLIB_CONST \
+$(gb_CXXFLAGS_include)$(SRCDIR)/pch/inc/clangfix.hxx \
+$(gb_CXXFLAGS_no_pch_warnings) \
+$(gb_PrecompiledHeader_ignore_flags_for_flags_file) \
+
+# Probably also update pch/inc/clangfix.hxx if you extend the list.
+
+# $(call gb_PrecompiledHeader_check_flags_internal,pchfileflags,flags,pchcxxfile)
+# Check if two sets of flags are compatible, allowing reuse of the PCH. Flags are compatible if
+# - they are the same
+# - the PCH is precompiled_system and the linktarget has additional defines listed above
+define gb_PrecompiledHeader_check_flags_internal
+$(if $(filter-out $(2),$(1)),$(filter-out $(2),$(1)), \
+ $(if $(filter-out $(1),$(2)),\
+ $(if $(filter-out precompiled_system,$(notdir $(3))),$(filter-out $(1),$(2)), \
+ $(foreach flag,$(filter-out $(1),$(2)),$(filter-out $(gb_PrecompiledHeader_ignore_flags_system),$(flag))) \
+ ) \
+ ,) \
+)
+endef
+
+endif
+
+# vim: set noet sw=4: