[UNIKRAFT PATCH 2/3] build: Provide option to localize symbols (LIBNAME_LOCALS(-y))

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Similar to exporting symbols, this patch introduces the option to
localize symbols. The file format of a localizing symbol files is the
same as for exporting symbols (e.g., `exportsyms.uk`: Plain-text, one
symbol name per line. Such files can be registered to
`$(LIBNAME_LOCALS)` and `$(LIBNAME_LOCALS-y)`. As soon as a
`localsyms.uk` file exists in a library import base, it is
automatically added to the list `$(LIBNAME_LOCALS)` (similar behavior
as the handling of `exportsyms.uk files).

Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
---
 support/build/Makefile.rules | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/support/build/Makefile.rules b/support/build/Makefile.rules
index 384f24f0..251efef8 100644
--- a/support/build/Makefile.rules
+++ b/support/build/Makefile.rules
@@ -190,6 +190,7 @@ UK_LIBS += $(1)
 $(eval $(call uc,$(1))_BASE    := $(_IMPORT_BASE))
 $(eval $(call uc,$(1))_BUILD   := $(BUILD_DIR)/$(1))
 $(eval $(call uc,$(1))_EXPORTS += $(wildcard $(_IMPORT_BASE)/exportsyms.uk))
+$(eval $(call uc,$(1))_LOCALS  += $(wildcard $(_IMPORT_BASE)/localsyms.uk))
 endef
 
 # addlib_s $libname,$switch
@@ -207,6 +208,7 @@ $(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 += $(wildcard $(_IMPORT_BASE)/exportsyms.uk))
+$(eval $(call uc,$(2))_LOCALS  += $(wildcard $(_IMPORT_BASE)/localsyms.uk))
 endef
 
 # addplatlib_s $platname,$libname,$switch
@@ -740,8 +742,10 @@ $(call libname2preolib,$(1)): $($(call 
vprefix_lib,$(1),OBJS)) \
 
 $(call libname2olib,$(1)): $(call libname2preolib,$(1)) \
                           $($(call vprefix_lib,$(1),EXPORTS)) $($(call 
vprefix_lib,$(1),EXPORTS-y)) \
+                          $($(call vprefix_lib,$(1),LOCALS)) $($(call 
vprefix_lib,$(1),LOCALS-y)) \
        $(call build_cmd,OBJCOPY,,$(call libname2olib,$(1)),\
                $(OBJCOPY) $(addprefix --keep-global-symbols=,$($(call 
vprefix_lib,$(1),EXPORTS)) $($(call vprefix_lib,$(1),EXPORTS-y))) \
+                          $(addprefix --localize-symbols=,$($(call 
vprefix_lib,$(1),LOCALS)) $($(call vprefix_lib,$(1),LOCALS-y))) \
                           $(OBJCFLAGS) $(OBJCFLAGS-y) \
                           $($(call vprefix_lib,$(1),OBJCFLAGS)) $($(call 
vprefix_lib,$(1),OBJCFLAGS-y)) \
                           $(call libname2preolib,$(1)) $(call 
libname2olib,$(1)))
-- 
2.20.1