genode/base/mk/lib.mk
Norman Feske fae63f4fa9 Merge base libraries into a single library
This patch simplifies the way of how Genode's base libraries are
organized. Originally, the base API was implemented in the form of many
small libraries such as 'thread', 'env', 'server', etc. Most of them
used to consist of only a small number of files. Because those libraries
are incorporated in any build, the checking of their inter-dependencies
made the build process more verbose than desired. Also, the number of
libraries and their roles (core only, non-core only, shared by both core
and non-core) were not easy to capture.

Hereby, the base libraries have been reduced to the following few
libraries:

- startup.mk contains the startup code for normal Genode processes.
  On some platform, core is able to use the library as well.
- base-common.mk contains the parts of the base library that are
  identical by core and non-core processes.
- base.mk contains the complete base API implementation for non-core
  processes

Consequently, the 'LIBS' declaration in 'target.mk' files becomes
simpler as well. In the most simple case, only the 'base' library must
be mentioned.

Fixes #18
2013-02-19 14:45:55 +01:00

188 lines
5.1 KiB
Makefile

##
## Rules for building a library target
##
## The following variables must be passed when calling this file:
##
## BASE_DIR - base directory of the build system
## REPOSITORIES - repositories providing libs and headers
## VERBOSE - build verboseness modifier
## VERBOSE_DIR - verboseness modifier for changing directories
## VERBOSE_MK - verboseness of make calls
## BUILD_BASE_DIR - base of build directory tree
## LIB_CACHE_DIR - library build cache location
## INSTALL_DIR - program target build directory
## DEPS - library dependencies
## REP_DIR - repository where the library resides
##
#
# Prevent <libname>.mk rules to be executed as default rule
#
all:
#
# Function that searches for files in all
# repositories and returns the first match.
#
select_from_repositories = $(firstword $(foreach REP,$(REPOSITORIES),$(wildcard $(REP)/$(1))))
#
# Include specifics, for example platform, kernel-api etc.
#
include $(SPEC_FILES)
#
# Include library build instructions
#
# We set the 'called_from_lib_mk' variable to allow the library decription file
# to respond to the build pass.
#
BACKUP_INC_DIR := $(INC_DIR)
called_from_lib_mk = yes
include $(LIB_MK)
#
# Sanity check for INC_DIR overrides
#
ifneq ($(filter-out $(INC_DIR),$(BACKUP_INC_DIR)),)
all: error_inc_dir_override
endif
error_inc_dir_override:
@$(ECHO) "Error: $(LIB_MK) overrides INC_DIR instead of appending" ; false
#
# Include lib-import descriptions of all used libraries and the target library
#
include $(foreach LIB,$(LIBS),$(call select_from_repositories,lib/import/import-$(LIB).mk))
#
# Include global definitions
#
include $(BASE_DIR)/mk/global.mk
#
# Name of <libname>.lib.a or <libname>.lib.so file to create
#
ifndef SHARED_LIB
LIB_A := $(addsuffix .lib.a,$(LIB))
LIB_FILENAME := $(LIB_A)
else
LIB_SO := $(addsuffix .lib.so,$(LIB))
INSTALL_SO := $(INSTALL_DIR)/$(LIB_SO)
LIB_FILENAME := $(LIB_SO)
endif
LIB_TAG := $(addsuffix .lib.tag,$(LIB))
#
# Link libgcc to shared libraries
#
# For static libraries, libgcc is not needed because it will be linked
# against the final target.
#
ifdef SHARED_LIB
LIBGCC = $(shell $(CC) $(CC_MARCH) -print-libgcc-file-name)
endif
#
# Build libraries position-independent
#
# This option is required for building shared objects but also for static
# libraries that are (potentially) linked against shared objects. Hence,
# we build all libraries with '-fPIC'.
#
CC_OPT_PIC ?= -fPIC
CC_OPT += $(CC_OPT_PIC)
#
# Print message for the currently built library
#
all: message
message:
$(MSG_LIB)$(LIB)
#
# Trigger the creation of the <libname>.lib.a or <libname>.lib.so file
#
all: $(LIB_TAG)
$(LIB_TAG): $(LIB_A) $(LIB_SO) $(INSTALL_SO)
@touch $@
include $(BASE_DIR)/mk/generic.mk
#
# Rule to build the <libname>.lib.a file
#
# Use $(OBJECTS) instead of $^ for specifying the list of objects to include
# in the archive because $^ may also contain non-object phony targets, e.g.,
# used by the integration of Qt4's meta-object compiler into the Genode
# build system.
#
$(LIB_A): $(OBJECTS)
$(MSG_MERGE)$(LIB_A)
$(VERBOSE)$(AR) -rc $@ $(OBJECTS)
#
# Prevent linkage of startup code against shared libraries except for ld.lib.so
#
ifdef SHARED_LIB
ifneq ($(LIB),ld)
override DEPS := $(filter-out startup.lib,$(DEPS))
endif
endif
#
# The 'sort' is needed to ensure the same link order regardless
# of the find order, which uses to vary among different systems.
#
STATIC_LIBS := $(foreach l,$(DEPS:.lib=),$(LIB_CACHE_DIR)/$l/$l.lib.a)
STATIC_LIBS := $(sort $(wildcard $(STATIC_LIBS)))
STATIC_LIBS_BRIEF := $(subst $(LIB_CACHE_DIR),$$libs,$(STATIC_LIBS))
#
# Rule to build the <libname>.lib.so file
#
# The 'LIBS' variable may contain static and shared sub libraries. When linking
# the shared library, we have to link all shared sub libraries to the library
# to store the library-dependency information in the library. Because we do not
# know which sub libraries are static or shared prior calling 'build_libs.mk',
# we use an explicit call to the 'lib_so_wildcard' macro to determine the subset
# of libraries that are shared.
#
# The 'ldso-startup/startup.o' object file, which contains the support code for
# constructing static objects must be specified as object file to prevent the
# linker from garbage-collecting it.
#
USED_SHARED_LIBS := $(filter $(DEPS:.lib=),$(SHARED_LIBS))
USED_SO_FILES := $(foreach s,$(USED_SHARED_LIBS),$(LIB_CACHE_DIR)/$s/$s.lib.so)
#
# Don't link ld libary against shared objects
#
USED_SO_FILES := $(filter-out %ld.lib.so,$(USED_SO_FILES))
#
# Default entry point of shared libraries
#
ENTRY_POINT ?= 0x0
$(LIB_SO): $(STATIC_LIBS) $(OBJECTS) $(wildcard $(LD_SCRIPT_SO))
$(MSG_MERGE)$(LIB_SO)
$(VERBOSE)libs=$(LIB_CACHE_DIR); $(LD) -o $(LIB_SO) -shared --eh-frame-hdr \
$(LD_OPT) \
-T $(LD_SCRIPT_SO) \
--entry=$(ENTRY_POINT) \
--whole-archive \
--start-group \
$(USED_SO_FILES) $(STATIC_LIBS_BRIEF) $(OBJECTS) \
--end-group \
--no-whole-archive \
$(LIBGCC)
$(INSTALL_SO):
$(VERBOSE)ln -sf $(CURDIR)/$(LIB_SO) $@