Generalize ABI mechanism to shared objects

This patch make the ABI mechanism available to shared libraries other
than Genode's dynamic linker. It thereby allows us to introduce
intermediate ABIs at the granularity of shared libraries. This is useful
for slow-moving ABIs such as the libc's interface but it will also
become handy for the package management.

To implement the feature, the build system had to be streamlined a bit.
In particular, archive dependencies and shared-lib dependencies are now
handled separately, and the global list of 'SHARED_LIBS' is no more.
Now, the variable with the same name holds the per-target list of shared
libraries used by the target.

repos/base/mk/prg.mk

@@ -11,6 +11,8 @@
 ##   VERBOSE          - build verboseness modifier
 ##   VERBOSE_DIR      - verboseness modifier for changing directories
 ##   VERBOSE_MK       - verboseness of make calls
+##   SHARED_LIBS      - shared-library dependencies of the target
+##   ARCHIVES         - archive dependencies of the target
 ##   LIB_CACHE_DIR    - library build cache location
 ##
 
@@ -19,11 +21,6 @@
 #
 all:
 
-#
-# Tell rust to make an object file instead of anything else
-#
-CC_RUSTC_OPT += --emit obj
-
 #
 # Include common utility functions
 #
@@ -62,7 +59,6 @@ endif
 #
 CXX_LINK_OPT += $(CC_MARCH)
 
-
 #
 # Generic linker script for statically linked binaries
 #
@@ -95,23 +91,14 @@ message:
 FORCE:
 $(SRC_ADA:.adb=.o): FORCE
 
-#
-# The 'sort' is needed to ensure the same link order regardless
-# of the find order, which uses to vary among different systems.
-#
-SHARED_LIBS := $(foreach l,$(DEPS:.lib=),$(LIB_CACHE_DIR)/$l/$l.lib.so)
-SHARED_LIBS := $(sort $(wildcard $(SHARED_LIBS)))
-
 #
 # Use CXX for linking
 #
 LD_CMD ?= $(CXX)
-
 LD_CMD += $(CXX_LINK_OPT)
 
 ifeq ($(SHARED_LIBS),)
-FILTER_DEPS := $(DEPS:.lib=)
-LD_SCRIPTS  := $(LD_SCRIPT_STATIC)
+LD_SCRIPTS := $(LD_SCRIPT_STATIC)
 else
 
 #
@@ -119,22 +106,14 @@ else
 #
 LD_OPT += --dynamic-list=$(call select_from_repositories,src/ld/genode_dyn.dl)
 
-LD_SCRIPTS  := $(LD_SCRIPT_DYN)
-LD_CMD      += -Wl,--dynamic-linker=$(DYNAMIC_LINKER).lib.so \
-               -Wl,--eh-frame-hdr
+LD_SCRIPTS := $(LD_SCRIPT_DYN)
+LD_CMD     += -Wl,--dynamic-linker=$(DYNAMIC_LINKER).lib.so \
+              -Wl,--eh-frame-hdr -Wl,-rpath-link=.
 
 #
 # Filter out the base libraries since they will be provided by the LDSO library
 #
-FILTER_DEPS := $(filter-out $(BASE_LIBS),$(DEPS:.lib=))
-SHARED_LIBS += $(LIB_CACHE_DIR)/$(DYNAMIC_LINKER)/$(DYNAMIC_LINKER).lib.so
-
-#
-# Build program position independent as well
-#
-CC_OPT_PIC ?= -fPIC
-CC_OPT     += $(CC_OPT_PIC)
-
+override ARCHIVES := $(filter-out $(BASE_LIBS:=.lib.a),$(ARCHIVES))
 endif
 
 #
@@ -142,7 +121,7 @@ endif
 # commas othwerwise. For compatibilty with older tool chains, we use two -Wl
 # parameters for both components of the linker command line.
 #
-LD_SCRIPT_PREFIX  = -Wl,-T -Wl,
+LD_SCRIPT_PREFIX := -Wl,-T -Wl,
 
 #
 # LD_SCRIPTS may be a list of linker scripts (e.g., in base-linux). Further,
@@ -151,26 +130,7 @@ LD_SCRIPT_PREFIX  = -Wl,-T -Wl,
 #
 LD_CMD += $(addprefix $(LD_SCRIPT_PREFIX), $(LD_SCRIPTS))
 
-STATIC_LIBS := $(foreach l,$(FILTER_DEPS),$(LIB_CACHE_DIR)/$l/$l.lib.a)
-STATIC_LIBS := $(sort $(wildcard $(STATIC_LIBS)))
-
-#
-# --whole-archive does not work with rlibs
-#
-RUST_LIBS := $(foreach l,$(FILTER_DEPS),$(LIB_CACHE_DIR)/$l/$l.rlib)
-RUST_LIBS :=  $(sort $(wildcard $(RUST_LIBS))) 
-SHORT_RUST_LIBS := $(subst $(LIB_CACHE_DIR),$$libs,$(RUST_LIBS))
-
-#
-# For hybrid Linux/Genode programs, prevent the linkage Genode's cxx and base
-# library because these functionalities are covered by the glibc or by
-# 'src/platform/lx_hybrid.cc'.
-#
-ifeq ($(USE_HOST_LD_SCRIPT),yes)
-STATIC_LIBS := $(filter-out $(LIB_CACHE_DIR)/startup/startup.lib.a, $(STATIC_LIBS))
-STATIC_LIBS := $(filter-out $(LIB_CACHE_DIR)/base/base.lib.a,       $(STATIC_LIBS))
-STATIC_LIBS := $(filter-out $(LIB_CACHE_DIR)/cxx/cxx.lib.a,         $(STATIC_LIBS))
-endif
+STATIC_LIBS := $(foreach l,$(ARCHIVES:.lib.a=),$(LIB_CACHE_DIR)/$l/$l.lib.a)
 
 #
 # We need the linker option '--whole-archive' to make sure that all library
@@ -184,7 +144,7 @@ endif
 # would go undetected if the search stops after the first match.
 #
 LINK_ITEMS       := $(OBJECTS) $(STATIC_LIBS) $(SHARED_LIBS)
-SHORT_LINK_ITEMS := $(subst $(LIB_CACHE_DIR),$$libs,$(LINK_ITEMS))
+LINK_ITEMS_BRIEF := $(subst $(LIB_CACHE_DIR),$$libs,$(LINK_ITEMS))
 
 #
 # Trigger the build of host tools
@@ -192,10 +152,9 @@ SHORT_LINK_ITEMS := $(subst $(LIB_CACHE_DIR),$$libs,$(LINK_ITEMS))
 $(LINK_ITEMS) $(TARGET): $(HOST_TOOLS)
 
 LD_CMD += -Wl,--whole-archive -Wl,--start-group
-LD_CMD += $(SHORT_LINK_ITEMS)
+LD_CMD += $(LINK_ITEMS_BRIEF)
 LD_CMD += $(EXT_OBJECTS)
 LD_CMD += -Wl,--no-whole-archive
-LD_CMD += $(SHORT_RUST_LIBS)
 LD_CMD += -Wl,--end-group
 
 #
@@ -211,7 +170,7 @@ LD_CMD += $(LD_LIBGCC)
 # $(TARGET).
 #
 ifneq ($(OBJECTS),)
-$(TARGET): $(LINK_ITEMS) $(wildcard $(LD_SCRIPTS))
+$(TARGET): $(LINK_ITEMS) $(wildcard $(LD_SCRIPTS)) $(LIB_SO_DEPS)
 	$(MSG_LINK)$(TARGET)
 	$(VERBOSE)libs=$(LIB_CACHE_DIR); $(LD_CMD) -o $@
 
@@ -225,6 +184,6 @@ endif
 clean_prg_objects:
 	$(MSG_CLEAN)$(PRG_REL_DIR)
 	$(VERBOSE)$(RM) -f $(OBJECTS) $(OBJECTS:.o=.d) $(TARGET)
-	$(VERBOSE)$(RM) -f *.d *.i *.ii *.s *.ali
+	$(VERBOSE)$(RM) -f *.d *.i *.ii *.s *.ali *.lib.so
 
 clean: clean_prg_objects