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# Desc:   APC make script
# Author: kgr
# Date:   2016
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# This makefile builds APC, the Asset Package Compiler for Henge, on the system.
################################################################################
# Driver sources
DRIVERS ?= apc testapc

# Debug Level
DEBUG   ?= 1

# Yacc
YACC   := bison
YFLAGS ?= -v -d -Wall
YCMD    = $(strip $(YACC) $(YFLAGS) $(if $2,$(dir $2))$1)
YCMD   += $(if $2,&& mv $(notdir $(1:%.y=%.tab.[ch])) $(dir $2))

# Ragel
RLC     ?= ragel
RLFLAGS ?= -C
RLCMD    = $(strip $(RLC) $(RLFLAGS) $(if $2,-o $2 $(dir $2))$1)

# C
CC     ?= gcc
CFLAGS ?= -Wall
CCMD    = $(strip $(CC) $(CFLAGS) $(CPPFLAGS) -c $(if $2,-o $2) $1)

# Linker
LD        ?= ld
LDFLAGS   ?= 
LDLIBS    ?= -lunistring
apcLIBS   ?= 
apc-dLIBS ?= 
LDCMD      = $(strip $(CC) $(LDFLAGS) $(if $2,-o $2) $1) $(LDLIBS) $($1LIBS) 

# APC is built from Ragel, Bison and C source code only.
ySRC  := $(shell find src/ -type f -name '*.y')
rlSRC := $(shell find src/ -type f -name '*.rl')
cSRC  := $(shell find src/ -type f -name '*.c')

# Generated files from Yacc/Bison and Ragel
hGEN  := $(ySRC:%.y=%.tab.h)
cGEN  := $(strip $(ySRC:%.y=%.tab.c) $(rlSRC:%.rl=%.fsm.c))
.SECONDARY: $(cGEN)

# Determine binary/ir targets (object files and driver binaries)
cTRG  := $(patsubst %.c,%.o,$(cSRC) $(cGEN))
ldSRC := $(filter-out $(DRIVERS:%=\%/%.o),$(cTRG))
cTRG  += $(cTRG:%.o=%-d.o)
ldTRG := $(DRIVERS:%=%-d) $(DRIVERS)
ldDEP  = $(filter %/$1.o,$(cTRG)) $(if $(filter %-d,$1),$(ldSRC:%.o=%-d.o),$(ldSRC))

# Determine if '1' is newer than '2'
TSTAMP = $(if $(wildcard $1),$(shell stat -c %Y $1),0$(info nots: $1))
NEWER  = $(eval 4 := $(call TSTAMP,$(dir $2)$1))
NEWER += $(eval 5 := $(call TSTAMP,$2))
NEWER += $(if $(filter $5,$(firstword $(sort $4 $5))),$1,$2)

ifeq (,$(filter clean,$(MAKECMDGOALS)))
# Deps should be generated for each source file, when not cleaning
cGENDEP = $(if $(wildcard $1),$(subst $(dir $1),,$(filter-out $1 \ %:,$(shell $(CC) -MM -MG $1))),\
$(info [<$1>: no deps - file not found]))
# Filter only missing deps
cMISDEP = $(strip $(foreach dep,$(call cGENDEP,$1),$(if $(wildcard src/$(dep)),,$(dep))))
# S2S will print the command necessary to create a file when called
S2S  = $(if $(filter $2,$(call NEWER,$2,$3)),$(eval 4 := t),$(eval 4 :=))
S2S += $(if $4,$(info $(call $1,$2,$3)))
ifeq (,$(filter n,$(MAKEFLAGS)))
# Unless we're in -n mode, S2S should also invoke the command on the shell
S2S += $(if $4,$(shell $(call $1,$2,$3)))
endif
endif

# Clean targets
cleanCMD = $(if $(wildcard $1),rm $(wildcard $(sort $1)))

# Rules
.SECONDEXPANSION:
$(ldTRG): $$(call ldDEP,$$@) | $(hGEN) ; $(call LDCMD,$^,$@)
%-d.o: CFLAGS+= -Og -ggdb -DDEBUG=$(DEBUG)
%.o %-d.o: %.c $$(call cGENDEP,$$(dir $$@)%.c); $(call CCMD,$<,$@)
%.o %-d.o: %.c; $(error Missing dependencies for $<: $(call cMISDEP, $<))
%.tab.h: %.tab.c ;
%.tab.c: %.y $$(call S2S,YCMD,%.y,$$@) ;
%.fsm.c: %.rl $$(call S2S,RLCMD,%.rl,$$@) ;
clean: ; $(call cleanCMD,$(cGEN) $(hGEN) $(cTRG))
distclean: clean ; $(call cleanCMD,$(ldTRG))