Re: Out-of-tree builds

[Szabolcs Nagy <nsz@port70.net>]

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* Szabolcs Nagy <nsz@port70.net> [2014-02-07 00:31:22 +0100]:
> 
> VPATH=$(SOMEDIR)
> %.o: $(ARCH)/%.s
> 

attached a make diff that can do out-of-tree build, by specifying
M=relative/path/to/musl

- config is not ready
- directory creation is a hack
- include/bits/alltypes.h is generated into the original repo
(include/bits is a symlink to the arch/bits dir)


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diff --git a/Makefile b/Makefile
index 0ab0bfd..fb9a83e 100644
--- a/Makefile
+++ b/Makefile
@@ -16,8 +16,9 @@ includedir = $(prefix)/include
 libdir = $(prefix)/lib
 syslibdir = /lib
 
-SRCS = $(sort $(wildcard src/*/*.c arch/$(ARCH)/src/*.c))
-OBJS = $(SRCS:.c=.o)
+M = .
+SRCS = $(sort $(wildcard $(M)/src/*/*.c $(M)/arch/$(ARCH)/src/*.c))
+OBJS = $(SRCS:$(M)/%.c=%.o)
 LOBJS = $(OBJS:.o=.lo)
 GENH = include/bits/alltypes.h
 GENH_INT = src/internal/version.h
@@ -30,17 +31,17 @@ CFLAGS = -Os -pipe
 CFLAGS_C99FSE = -std=c99 -ffreestanding -nostdinc 
 
 CFLAGS_ALL = $(CFLAGS_C99FSE)
-CFLAGS_ALL += -D_XOPEN_SOURCE=700 -I./arch/$(ARCH) -I./src/internal -I./include
+CFLAGS_ALL += -D_XOPEN_SOURCE=700 -I$(M)/arch/$(ARCH) -I./src/internal -I$(M)/src/internal -I./include -I$(M)/include
 CFLAGS_ALL += $(CPPFLAGS) $(CFLAGS)
 CFLAGS_ALL_STATIC = $(CFLAGS_ALL)
 CFLAGS_ALL_SHARED = $(CFLAGS_ALL) -fPIC -DSHARED
 
 AR      = $(CROSS_COMPILE)ar
 RANLIB  = $(CROSS_COMPILE)ranlib
-INSTALL = ./tools/install.sh
+INSTALL = $(M)/tools/install.sh
 
-ARCH_INCLUDES = $(wildcard arch/$(ARCH)/bits/*.h)
-ALL_INCLUDES = $(sort $(wildcard include/*.h include/*/*.h) $(GENH) $(ARCH_INCLUDES:arch/$(ARCH)/%=include/%))
+ARCH_INCLUDES = $(wildcard $(M)/arch/$(ARCH)/bits/*.h)
+ALL_INCLUDES = $(sort $(wildcard $(M)/include/*.h $(M)/include/*/*.h) $(GENH) $(ARCH_INCLUDES:$(M)/arch/$(ARCH)/%=include/%))
 
 EMPTY_LIB_NAMES = m rt pthread crypt util xnet resolv dl
 EMPTY_LIBS = $(EMPTY_LIB_NAMES:%=lib/lib%.a)
@@ -55,7 +56,12 @@ LDSO_PATHNAME = $(syslibdir)/ld-musl-$(ARCH)$(SUBARCH).so.1
 
 -include config.mak
 
-all: $(ALL_LIBS) $(ALL_TOOLS)
+VPATH = $(M)
+
+all: dirhack $(ALL_LIBS) $(ALL_TOOLS)
+
+dirhack:
+	mkdir -p $(sort $(dir $(OBJS))) crt include lib tools
 
 install: install-libs install-headers install-tools
 
@@ -73,26 +79,26 @@ distclean: clean
 
 include/bits:
 	@test "$(ARCH)" || { echo "Please set ARCH in config.mak before running make." ; exit 1 ; }
-	ln -sf ../arch/$(ARCH)/bits $@
+	ln -sf ../$(M)/arch/$(ARCH)/bits $@
 
 include/bits/alltypes.h.in: include/bits
 
-include/bits/alltypes.h: include/bits/alltypes.h.in include/alltypes.h.in tools/mkalltypes.sed
-	sed -f tools/mkalltypes.sed include/bits/alltypes.h.in include/alltypes.h.in > $@
+include/bits/alltypes.h: include/bits/alltypes.h.in $(M)/include/alltypes.h.in $(M)/tools/mkalltypes.sed
+	sed -f $(M)/tools/mkalltypes.sed include/bits/alltypes.h.in $(M)/include/alltypes.h.in > $@
 
-src/internal/version.h: $(wildcard VERSION .git)
-	printf '#define VERSION "%s"\n' "$$(sh tools/version.sh)" > $@
+src/internal/version.h: $(wildcard $(M)/VERSION $(M)/.git)
+	printf '#define VERSION "%s"\n' "$$(cd $(M); sh tools/version.sh)" > $@
 
 src/internal/version.lo: src/internal/version.h
 
 src/ldso/dynlink.lo: arch/$(ARCH)/reloc.h
 
-crt/crt1.o crt/Scrt1.o: $(wildcard arch/$(ARCH)/crt_arch.h)
+crt/crt1.o crt/Scrt1.o: $(wildcard $(M)/arch/$(ARCH)/crt_arch.h)
 
 crt/Scrt1.o: CFLAGS += -fPIC
 
-OPTIMIZE_SRCS = $(wildcard $(OPTIMIZE_GLOBS:%=src/%))
-$(OPTIMIZE_SRCS:%.c=%.o) $(OPTIMIZE_SRCS:%.c=%.lo): CFLAGS += -O3
+OPTIMIZE_SRCS = $(wildcard $(OPTIMIZE_GLOBS:%=$(M)/src/%))
+$(OPTIMIZE_SRCS:$(M)/%.c=%.o) $(OPTIMIZE_SRCS:$(M)/%.c=%.lo): CFLAGS += -O3
 
 MEMOPS_SRCS = src/string/memcpy.c src/string/memmove.c src/string/memcmp.c src/string/memset.c
 $(MEMOPS_SRCS:%.c=%.o) $(MEMOPS_SRCS:%.c=%.lo): CFLAGS += $(CFLAGS_MEMOPS)
@@ -101,9 +107,9 @@ $(MEMOPS_SRCS:%.c=%.o) $(MEMOPS_SRCS:%.c=%.lo): CFLAGS += $(CFLAGS_MEMOPS)
 # force the corresponding object file to be rebuilt, even if the implicit
 # rule below goes indirectly through a .sub file.
 define mkasmdep
-$(dir $(patsubst %/,%,$(dir $(1))))$(notdir $(1:.s=.o)): $(1)
+$(dir $(patsubst $(M)/%/,%,$(dir $(1))))$(notdir $(1:.s=.o)): $(1)
 endef
-$(foreach s,$(wildcard src/*/$(ARCH)*/*.s),$(eval $(call mkasmdep,$(s))))
+$(foreach s,$(wildcard $(M)/src/*/$(ARCH)*/*.s),$(eval $(call mkasmdep,$(s))))
 
 %.o: $(ARCH)$(ASMSUBARCH)/%.sub
 	$(CC) $(CFLAGS_ALL_STATIC) -c -o $@ $(dir $<)$(shell cat $<)