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author | Luboš Luňák <l.lunak@collabora.com> | 2019-09-22 20:28:38 +0200 |
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committer | Luboš Luňák <l.lunak@collabora.com> | 2019-10-04 08:59:13 +0200 |
commit | 98dc4ec4957ffa520c9acb21d2477df36496a000 (patch) | |
tree | ab76a20e0660911584d91b444b7369d0ef383841 /solenv/gbuild/PrecompiledHeaders.mk | |
parent | 08d02b550a1aee0e109334384c260244d450d6a0 (diff) |
support reusing PCH if linktarget has additional reasonable defines
Where reasonable means they are from a list of defines known not
to affect the system headers, and so they are safe to differ from
how the PCH was built. A bit hackish, but works in practice.
Change-Id: Ia00d2e4c56212aca05ba9d47abbb0d253998219f
Reviewed-on: https://gerrit.libreoffice.org/79364
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>
Diffstat (limited to 'solenv/gbuild/PrecompiledHeaders.mk')
-rw-r--r-- | solenv/gbuild/PrecompiledHeaders.mk | 97 |
1 files changed, 77 insertions, 20 deletions
diff --git a/solenv/gbuild/PrecompiledHeaders.mk b/solenv/gbuild/PrecompiledHeaders.mk index 8854784c5a41..d04059296cad 100644 --- a/solenv/gbuild/PrecompiledHeaders.mk +++ b/solenv/gbuild/PrecompiledHeaders.mk @@ -29,39 +29,46 @@ gb_PrecompiledHeader__get_debugdir = $(if $(call gb_LinkTarget__symbols_enabled, # for $(1)'s and things that are constant. # The defines are needed to get the right version of gb_PrecompiledHeader__get_debugdir. -# $(call gb_PrecompiledHeader_generate_rules,pchtarget,linktargetmakefilename) +# $(call gb_PrecompiledHeader_generate_rules,pchtarget,linktarget,linktargetmakefilename) define gb_PrecompiledHeader_generate_rules -$(call gb_PrecompiledHeader_get_dep_target,$(1),$(2)) : +$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)) : $$(call gb_Helper_abbreviate_dirs,\ mkdir -p $$(dir $$@) && \ - echo "$$(call gb_PrecompiledHeader_get_target,$(1),$(2)) : $$(gb_Helper_PHONY)" > $$@) + echo "$$(call gb_PrecompiledHeader_get_target,$(1),$(3)) : $$(gb_Helper_PHONY)" > $$@) # despite this being only one .d file, need to run concat-deps on it to # re-write external headers from UnpackedTarball -$(call gb_PrecompiledHeader_get_target,$(1),$(2)) : +$(call gb_PrecompiledHeader_get_target,$(1),$(3)) : + test "$$(PCH_LINKTARGETMAKEFILENAME)" = "$(3)" \ + || ( echo "Error, PCH $(1) built by $$(PCH_LINKTARGETMAKEFILENAME) instead of $(3)" >&2; exit 1) rm -f $$@ - $$(call gb_PrecompiledHeader__command,$$@,$(1),$$<,$$(PCH_DEFS),$$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS),$$(INCLUDE),$(2)) - $$(call gb_PrecompiledHeader__sum_command,$$@,$(1),$$<,$$(PCH_DEFS),$$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS),$$(INCLUDE),$(2)) - echo $$(sort $$(PCH_DEFS) $$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS)) > $$(call gb_PrecompiledHeader_get_target,$(1),$(2)).flags + $$(call gb_PrecompiledHeader__command,$$@,$(1),$$<,$$(PCH_DEFS),$$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS),$$(INCLUDE),$(3)) + $$(call gb_PrecompiledHeader__sum_command,$$@,$(1),$$<,$$(PCH_DEFS),$$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS),$$(INCLUDE),$(3)) + echo $$(sort $$(PCH_DEFS) $$(PCH_CXXFLAGS) $$(gb_PrecompiledHeader_EXCEPTIONFLAGS)) > $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).flags ifeq ($(gb_FULLDEPS),$(true)) $$(call gb_Helper_abbreviate_dirs,\ - RESPONSEFILE=$$(call var2file,$$(shell $$(gb_MKTEMP)),200,$$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(2))) && \ + RESPONSEFILE=$$(call var2file,$$(shell $$(gb_MKTEMP)),200,$$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(3))) && \ $$(call gb_Executable_get_command,concat-deps) $$$${RESPONSEFILE} \ - > $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(2)) && \ - rm -f $$$${RESPONSEFILE} $$(call gb_PrecompiledHeader_get_dep_target_tmp,$(1),$(2))) + > $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3)) && \ + rm -f $$$${RESPONSEFILE} $$(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 $$(call gb_PrecompiledHeader_get_target,$(1),$(2)) \ - $$(call gb_PrecompiledHeader_get_target,$(1),$(2)).obj \ - $$(call gb_PrecompiledHeader_get_target,$(1),$(2)).pdb \ - $$(call gb_PrecompiledHeader_get_target,$(1),$(2)).sum \ - $$(call gb_PrecompiledHeader_get_target,$(1),$(2)).flags \ - $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(2))) + 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 \ + $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).flags \ + $$(call gb_PrecompiledHeader_get_target,$(1),$(3)).reuse \ + $$(call gb_PrecompiledHeader_get_dep_target,$(1),$(3))) endef @@ -74,22 +81,72 @@ $(call gb_LinkTarget_get_pch_timestamp,$(1)) : endef -# $(call gb_PrecompiledHeader_check_saved_flags_command_pattern,linktargetmakefilename,pchcxxfile,pchfile,flags) +# $(call gb_PrecompiledHeader_check_flags,linktargetmakefilename,pchcxxfile,pchfile,flags) # When creating a PCH, the PCH's CXXFLAGS are saved to a matching .flags file. When reusing the PCH # from another linktarget, use the file to check that the linktarget uses the same CXXFLAGS as the PCH. # This complements the check in gb_CxxObject__set_pchflags. define gb_PrecompiledHeader_check_flags $$(call gb_Helper_abbreviate_dirs,\ - grep -q -x -F -- "$$(sort $(4))" $(3).flags || ( \ + $$(if $$(strip $$(call gb_PrecompiledHeader_check_flags_internal,$$(shell cat $(3).flags),$(4),$(2))),false,true) || ( \ echo Error reusing $(2) by $(1). >&2 && \ echo -n " precompiled header flags : ">&2 && \ cat $(3).flags >&2 && \ echo " object flags : "$$(sort $(4)) >&2 && \ + echo " reason : $$(call gb_PrecompiledHeader_check_flags_internal,$$(shell cat $(3).flags),$(4),$(2))" >&2 && \ echo Incorrect precompiled header setup or internal gbuild error. >&2 ; \ - exit 1) && \ - mkdir -p $$(dir $$@) && touch $$@ \ + 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 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 \ +-DFASTSAX_DLLIMPLEMENTATION \ +-DSYSTEM_EXPAT \ +-DSYSTEM_LIBXML \ +-DSYSTEM_ZLIB \ +-include $(SRCDIR)/pch/inc/clangfix.hxx \ + +# 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 + # vim: set noet sw=4: |