#! /usr/bin/make -f
#---
#
#  fxlibc project Makefile
#
# This makefile is grandly inspired by the Gint unikernel
# projet, many thanks to Lephenixnoir !
#
# Build architecture:
# build/
#  |-- objects/
#  |    |-- string_strlen.o
#  |    |-- string_strcmp.o
#  |      ...
#  |    `-- signal_kill.o
#  |-- debug/
#  |    |-- fxlibc.map (ELF link map informations)
#  |      ...
#  |    `--  otherinfo.txt
#  |-- Makefile
#  |-- fxlibc.cfg
#  `-- ouptut/
#       |-- static/
#       |    |--- libfxlibc.a
#       |    |--- libfxlibc-casio-abi-fx9860.a
#       |    `--- libfxlibc-casio-abi-fxcg50.a
#       `--- dynamic/
#            |--- libfxlibc.so
#            |--- libfxlibc-casio-abi-fx9860.so
#            `--- libfxlibc-casio-abi-fxcg50.so
#
# TODO:
# * handle versionning
#---
MAJOR	:= 0
MINOR	:= 2
PATCH	:= 3
EXTRAVERSION	:= -alpha


#---
#  Build configuration
#---
# Require configuration file (if you want to clean up and lost the file, you
# can either reconfigure or just delete the build directory)
CONFIG := fxlibc.cfg
ifeq "$(wildcard $(CONFIG))" ""
$(error "config file $(CONFIG) does not exist (reconfigure or wipe directory)")
endif
include $(CONFIG)

# Compiler flags, assembler flags, dependency generation, archiving
header	:= ../include
cflags	:= $(machine) -ffreestanding -nostdlib -Wall -Wextra -std=c11 -Os \
		-fstrict-volatile-bitfields -I$(header) $(CONFIG.CFLAGS)

# color definition
red	:= \033[1;31m
green	:= \033[1;32m
blue	:= \033[1;34m
white	:= \033[1;37m
nocolor	:= \033[1;0m

# This is a workaround to force a newline when the "eval" keyword is involved
define n
# Force newline character

endef

# Define all directory used to stored informations
dir_object	:= object
dir_output	:= output

# Output configurations
name		:= fxlibc

# automated variable
directory	:= $(shell find ../src -not -path "*/\.*" -type d)
src 		:= $(foreach path,$(directory), \
			$(wildcard $(path)/*.c)	\
			$(wildcard $(path)/*.S) \
			$(wildcard $(path)/*.s))




#---
# Toolchain
#---
gcc	= $(CONFIG.TOOLCHAIN)-gcc
as	= $(CONFIG.TOOLCHAIN)-as
ld	= $(CONFIG.TOOLCHAIN)-ld
ar	= $(CONFIG.TOOLCHAIN)-ar
objcopy	= $(CONFIG.TOOLCHAIN)-objcopy




#---
# Build rules
#---
# (Make selects the first rule when you type "make" and I don't want the first
# rule to be "%/" so here's a placeholder)
first: all

# Create directory helper
# @note: Just use "$*" and "$@" to refer to the directory being created.
%/:
	@ printf "Create $(blue)$*$(nocolor) directory\n"
	@ mkdir -p $@
.PRECIOUS: %/




#---
# Automated rules
#---
# common part used to compile source file
# @params:
# *1 - source file path
# *2 - build directory path (output)
# *3 - build flags
# TODO:
# * handle verbose option
define compile-src
$(patsubst .._src_%,$2%.o,$(subst /,_,$(basename $1))): $1 | $2/
	@ printf "$(green)>$(nocolor) $(white)$$@$(nocolor)\n"
	@ $(gcc) $3 -o $$@ -c $$< -lgcc
endef

# common part used by all library geneation
# @params:
# * 1 - library name
# * 2 - format (dynamic/static)
# * 3 - source file list
define generate-target
# generate the library name based on the wanted formats
lib-output-dir	:= $(dir_output)/$2/
lib-build-dir	:= $(dir_object)/$2/$1/
ifeq ($2,dynamic)
lib-name	:= $$(lib-output-dir)lib$1.so.$$(lib-version)
lib-cflags	:= -fPIC $(cflags)
else
lib-name	:= $$(lib-output-dir)lib$1.a
lib-cflags	:= $(cflags)
endif

# indicate the new lib that will be ouputed
generated-libs += $$(lib-name)

# add custom flags based on the target ABI
ifeq ($1,fxlibc-vhex)
lib-cflags	+= -D __SUPPORT_VHEX_KERNEL
else ifeq ($1,fxlibc-casio-abi-fx9860g)
lib-cflags	+= -D __SUPPORT_CASIO_ABI_FX9860G
else ifeq ($1,fxlibc-casio-abi-fxcf50)
lib-cflags	+= -D __SUPPORT_CASIO_ABI_FXCG50
endif

# generate all file object name
$$(foreach source,$3,$$(eval \
	$$(call compile-src,$$(source),$$(lib-build-dir),$$(lib-cflags)) \
))

# link the library
# @note: we need to generate the library verion information manually
# TODO: find a better way to generate the version symbols
$$(lib-name): $$(patsubst .._src_%,$$(lib-build-dir)%.o,$$(subst /,_,$$(basename $3))) | $$(lib-output-dir)
ifeq ($2,dynamic)
	$(gcc) -shared -Wl,-soname=$$@ -o $$@ $$^ -nostdlib -lgcc
else
	$(ar) crs $$@ $$^
endif
endef

# create all "target" variable used to determine which format
# and which libraries will be generated.
# @note:
# * we force default variable if nothing is set
target-formats	:= $(if $(CONFIG.FORMAT),$(CONFIG.FORMAT),static)
target-libs	:= $(if $(CONFIG.TARGET),$(CONFIG.TARGET),fxlibc)

# create a variable that will be updated during the generation of
# the dynamic make code generation (generated by the "foreach")
generated-libs	:=

# generate the library version
lib-version	:= $(MAJOR).$(MINOR).$(PATCH)$(EXTRAVERSION)

# Generate all targets
$(foreach format,$(target-formats), \
	$(foreach lib,$(target-libs),$(eval \
		$(call generate-target,$(lib),$(format),$(src)) \
	)) \
)




#---
# Build rule
#---
all: $(generated-libs)

version:
	@ echo "$(lib-version)"

DEBUG=$(call generate-target,fxlibc-vhex,static,$(dir_objects),$(src))
export DEBUG
debug:
	@ echo "$$DEBUG"
	@ echo "target-lib: $(target-libs)"
	@ echo "generated lib: $(generated-libs)"
	@ echo "target format: $(target-formats)"


#---
# clean rules
#---
clean:
	rm -rf $(dir_object)
fclean: clean
	rm -rf $(dir_output)
re: fclean all
.PHONY: clean fclean re