Re: [Minios-devel] [UNIKRAFT PATCH v5 1/4] build: Introduce symbols exporting for each library

[Florian Schmidt <Florian.Schmidt@xxxxxxxxx>]

Reviewed-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>

On 09/03/2018 02:17 PM, Simon Kuenzer wrote:
> In order to avoid symbol conflicts and relaxing on namespacing
> of library-internal symbols, each library should provide
> an `exportsyms.uk` file in its base directory. This file
> lists the name of all symbols that should be exported
> by the library, the rest is treated as internal symbol
> which cannot be linked by another library. A warning is
> thrown by `make` whenever this symbols file is absent.
> The scope of each symbol for such a library stays unchanged.
> This way, this patch won't break existing Unikraft projects
> and libraries.
>
> The location of this file can be overwritten by defining the
> path with the [LIBNAME]_EXPORTS variable within the
> appropriate `Makefile.uk`.
>
> Signed-off-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
> Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
> Reviewed-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
> ---
>   support/build/Makefile.rules | 21 ++++++++++++++-------
>   1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/support/build/Makefile.rules b/support/build/Makefile.rules
> index e317e3d..35e2921 100644
> --- a/support/build/Makefile.rules
> +++ b/support/build/Makefile.rules
> @@ -121,8 +121,9 @@ endef
>   define addlib =
>   $(call mk_sub_build_dir,$(1))
>   UK_LIBS += $(1)
> -$(eval $(call uc,$(1))_BASE  := $(_IMPORT_BASE))
> -$(eval $(call uc,$(1))_BUILD := $(BUILD_DIR)/$(1))
> +$(eval $(call uc,$(1))_BASE    := $(_IMPORT_BASE))
> +$(eval $(call uc,$(1))_BUILD   := $(BUILD_DIR)/$(1))
> +$(eval $(call uc,$(1))_EXPORTS := $(_IMPORT_BASE)/exportsyms.uk)
>   endef
>   
>   # addlib_s $libname,$switch
> @@ -136,9 +137,10 @@ endef
>   # addplatlib $platname,$libname
>   define addplatlib =
>   $(call mk_sub_build_dir,$(2))
> -$(eval $(call uc,$(1))_LIBS  += $(2))
> -$(eval $(call uc,$(2))_BASE  := $(_IMPORT_BASE))
> -$(eval $(call uc,$(2))_BUILD := $(BUILD_DIR)/$(2))
> +$(eval $(call uc,$(1))_LIBS    += $(2))
> +$(eval $(call uc,$(2))_BASE    := $(_IMPORT_BASE))
> +$(eval $(call uc,$(2))_BUILD   := $(BUILD_DIR)/$(2))
> +$(eval $(call uc,$(2))_EXPORTS := $(_IMPORT_BASE)/exportsyms.uk)
>   endef
>   
>   # addplatlib_s $platname,$libname,$switch
> @@ -412,6 +414,10 @@ endef
>   
>   # buildrule_olib $libname
>   define buildrule_olib =
> +$(if $(wildcard $($(call vprefix_lib,$(1),EXPORTS))),,\
> +       $(warning Warning: Definition of exported symbols for $(1) missing: 
> $($(call vprefix_lib,$(1),EXPORTS))) \
> +)
> +
>   $(call libname2preolib,$(1)): $($(call vprefix_lib,$(1),OBJS)) $($(call 
> vprefix_lib,$(1),OBJS-y))
>         $(call build_cmd,LD,,$(call libname2preolib,$(1)),\
>                 $(LD) $(LIBLDFLAGS) $(LIBLDFLAGS-y) \
> @@ -419,9 +425,10 @@ $(call libname2preolib,$(1)): $($(call 
> vprefix_lib,$(1),OBJS)) $($(call vprefix_
>                       $($(call vprefix_lib,$(1),OBJS)) $($(call 
> vprefix_lib,$(1),OBJS-y)) \
>                       -o $(call libname2preolib,$(1)))
>   
> -$(call libname2olib,$(1)): $(call libname2preolib,$(1))
> +$(call libname2olib,$(1)): $(call libname2preolib,$(1)) $(if $(wildcard 
> $($(call vprefix_lib,$(1),EXPORTS))),$($(call vprefix_lib,$(1),EXPORTS)),)
>         $(call build_cmd,OBJCOPY,,$(call libname2olib,$(1)),\
> -               $(OBJCOPY) $(OBJCFLAGS) $(OBJCFLAGS-y) \
> +               $(OBJCOPY) $(if $(wildcard $($(call 
> vprefix_lib,$(1),EXPORTS))),--keep-global-symbols=$($(call 
> vprefix_lib,$(1),EXPORTS)),) \
> +                          $(OBJCFLAGS) $(OBJCFLAGS-y) \
>                            $($(call vprefix_lib,$(1),OBJCFLAGS)) $($(call 
> vprefix_lib,$(1),OBJCFLAGS-y)) \
>                            $(call libname2preolib,$(1)) $(call 
> libname2olib,$(1)))
>   
--
Dr. Florian Schmidt
フローリアン・シュミット
Research Scientist,
Systems and Machine Learning Group
NEC Laboratories Europe
Kurfürsten-Anlage 36, D-69115 Heidelberg
Tel.     +49 (0)6221 4342-265
Fax:     +49 (0)6221 4342-155
e-mail:  florian.schmidt@xxxxxxxxx
============================================================
Registered at Amtsgericht Mannheim, Germany, HRB728558

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