Makefile: define build result directories

Final build results (.elf, .debug, .map) are to be placed under
directory $(objcbfs), the default is:
   $(obj)/cbfs/$(CONFIG_CBFS_PREFIX)/

Intermediate build results (.o, .s, .S, .inc, .ld) that do not have
a clear one-to-one relation to a file under src/ are to be placed
under directory $(objgenerated), the default is:
   $(obj)/generated

Also defines implicit rules for final build results:

  .debug -> .elf and .map
  .elf -> .bin

Change-Id: I448c6b7c9a952e54170df42091d7db438025a795
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/858
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

Makefile.inc

@@ -27,14 +27,25 @@ ARCHDIR-$(CONFIG_ARCH_X86) := x86
 MAINBOARDDIR=$(call strip_quotes,$(CONFIG_MAINBOARD_DIR))
 export MAINBOARDDIR
 
+## Final build results, which CBFSTOOL uses to create the final
+## rom image file, are placed under $(objcbfs).
+## These typically have suffixes .debug .elf .bin and .map
+export objcbfs := $(obj)/cbfs/$(CONFIG_CBFS_PREFIX)
+
+## Based on the active configuration, Makefile conditionally collects
+## the required assembly includes and saves them in a file.
+## Such files that do not have a clear one-to-one relation to a source
+## file under src/ are placed and built under $(objgenerated)
+export objgenerated := $(obj)/generated
+
 #######################################################################
 # root rule to resolve if in build mode (ie. configuration exists)
 real-target: $(obj)/config.h coreboot
-coreboot: $(obj)/coreboot.rom
+coreboot: build-dirs $(obj)/coreboot.rom
 
 #######################################################################
 # our phony targets
-PHONY+= clean-abuild coreboot lint lint-stable
+PHONY+= clean-abuild coreboot lint lint-stable build-dirs
 
 #######################################################################
 # root source directories of coreboot
@@ -168,6 +179,9 @@ $(obj)/build.h: .xcompile
 $(obj)/ldoptions: $(obj)/config.h
 	awk '/^#define ([^"])* ([^"])*$$/ {gsub("\\r","",$$3); print $$2 " = " $$3 ";";}' $< > $@
 
+build-dirs:
+	mkdir -p $(objcbfs) $(objgenerated)
+
 #######################################################################
 # Build the tools
 CBFSTOOL:=$(obj)/cbfstool

src/arch/x86/Makefile.inc

@@ -138,6 +138,21 @@ $(obj)/cmos_layout.bin: $(NVRAMTOOL) $(top)/src/mainboard/$(MAINBOARDDIR)/cmos.l
 	@printf "    OPTION     $(subst $(obj)/,,$(@))\n"
 	$(NVRAMTOOL) -y $(top)/src/mainboard/$(MAINBOARDDIR)/cmos.layout -L $@
 
+#######################################################################
+# Common recipes for all stages
+
+$(objcbfs)/%.bin: $(objcbfs)/%.elf
+	@printf "    OBJCOPY    $(subst $(obj)/,,$(@))\n"
+	$(OBJCOPY) -O binary $< $@
+
+$(objcbfs)/%.elf: $(objcbfs)/%.debug
+	@printf "    OBJCOPY    $(subst $(obj)/,,$(@))\n"
+	cp $< $@.tmp
+	$(NM) -n $@.tmp | sort > $(basename $@).map
+	$(OBJCOPY) --strip-debug $@.tmp
+	$(OBJCOPY) --add-gnu-debuglink=$< $@.tmp
+	mv $@.tmp $@
+
 #######################################################################
 # Build the coreboot_ram (stage 2)