Switch from archive libraries to partial linking

Before this commit, weak symbols were not overridden by non-weak symbols
found in archive libraries when linking with recent versions of
binutils.  As stated in the System V ABI, "the link editor does not
extract archive members to resolve undefined weak symbols".

This commit changes all Makefiles to use partial linking (ld -r) instead
of creating library archives, which forces all symbols to participate in
linking, allowing non-weak symbols to override weak symbols as intended.
This approach is also used by Linux, from which the gmake function
cmd_link_o_target (defined in config.mk and used in all Makefiles) is
inspired.

The name of each former library archive is preserved except for
extensions which change from ".a" to ".o".  This commit updates
references accordingly where needed, in particular in some linker
scripts.

This commit reveals board configurations that exclude some features but
include source files that depend these disabled features in the build,
resulting in undefined symbols.  Known such cases include:
- disabling CMD_NET but not CMD_NFS;
- enabling CONFIG_OF_LIBFDT but not CONFIG_QE.

Signed-off-by: Sebastien Carlier <sebastien.carlier@gmail.com>

12 files changed, 20 insertions, 22 deletions

diff --git a/post/Makefile b/post/Makefile
index 169d126324..200e2f1b9a 100644
--- a/post/Makefile
+++ b/post/Makefile
@@ -24,20 +24,20 @@
 include $(TOPDIR)/config.mk
 include $(OBJTREE)/include/autoconf.mk
 
-LIB				= libpost.a
-GPLIB-$(CONFIG_HAS_POST)	+= libgenpost.a
+LIB				= libpost.o
+GPLIB-$(CONFIG_HAS_POST)	+= libgenpost.o
 COBJS-$(CONFIG_HAS_POST)	+= post.o
 COBJS-$(CONFIG_POST_STD_LIST)	+= tests.o
 
-SPLIB-$(CONFIG_HAS_POST) = drivers/libpostdrivers.a
+SPLIB-$(CONFIG_HAS_POST) = drivers/libpostdrivers.o
 SPLIB-$(CONFIG_HAS_POST) += $(shell if [ -d lib_$(ARCH) ]; then echo \
-			    "lib_$(ARCH)/libpost$(ARCH).a"; fi)
+			    "lib_$(ARCH)/libpost$(ARCH).o"; fi)
 SPLIB-$(CONFIG_HAS_POST) += $(shell if [ -d lib_$(ARCH)/fpu ]; then echo \
-			    "lib_$(ARCH)/fpu/libpost$(ARCH)fpu.a"; fi)
+			    "lib_$(ARCH)/fpu/libpost$(ARCH)fpu.o"; fi)
 SPLIB-$(CONFIG_HAS_POST) += $(shell if [ -d cpu/$(CPU) ]; then echo \
-			    "cpu/$(CPU)/libpost$(CPU).a"; fi)
+			    "cpu/$(CPU)/libpost$(CPU).o"; fi)
 SPLIB-$(CONFIG_HAS_POST) += $(shell if [ -d board/$(BOARD) ]; then echo \
-			    "board/$(BOARD)/libpost$(BOARD).a"; fi)
+			    "board/$(BOARD)/libpost$(BOARD).o"; fi)
 
 GPLIB	:= $(addprefix $(obj),$(GPLIB-y))
 SPLIB	:= $(addprefix $(obj),$(SPLIB-y))
@@ -55,7 +55,7 @@ postdeps:
 
 # generic POST library
 $(GPLIB): $(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 # specific POST libraries
 $(SPLIB): $(obj).depend postdeps
@@ -63,9 +63,7 @@ $(SPLIB): $(obj).depend postdeps
 
 # the POST lib archive
 $(LIB): $(GPLIB) $(SPLIB)
-	(echo create $(LIB); for lib in $(GPLIB) $(SPLIB) ; \
-	 do echo addlib $$lib; done; echo save) \
-	| $(AR) -M
+	$(call cmd_link_o_target, $^)
 
 #########################################################################
 
diff --git a/post/board/lwmon/Makefile b/post/board/lwmon/Makefile
index d2932bed13..83026c0713 100644
--- a/post/board/lwmon/Makefile
+++ b/post/board/lwmon/Makefile
@@ -22,7 +22,7 @@
 #
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostlwmon.a
+LIB	= libpostlwmon.o
 
 COBJS-$(CONFIG_HAS_POST)	+= sysmon.o
 
diff --git a/post/board/lwmon5/Makefile b/post/board/lwmon5/Makefile
index 4e95515ef1..b1996887cd 100644
--- a/post/board/lwmon5/Makefile
+++ b/post/board/lwmon5/Makefile
@@ -22,7 +22,7 @@
 # MA 02111-1307 USA
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostlwmon5.a
+LIB	= libpostlwmon5.o
 
 COBJS-$(CONFIG_HAS_POST)	+= sysmon.o watchdog.o dspic.o fpga.o dsp.o gdc.o
 
diff --git a/post/board/netta/Makefile b/post/board/netta/Makefile
index 8a8578f439..2d34dd8d03 100644
--- a/post/board/netta/Makefile
+++ b/post/board/netta/Makefile
@@ -22,7 +22,7 @@
 #
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostnetta.a
+LIB	= libpostnetta.o
 
 COBJS-$(CONFIG_HAS_POST)	+= codec.o dsp.o
 
diff --git a/post/board/pdm360ng/Makefile b/post/board/pdm360ng/Makefile
index d1538f6727..d25b0d151a 100644
--- a/post/board/pdm360ng/Makefile
+++ b/post/board/pdm360ng/Makefile
@@ -22,7 +22,7 @@
 #
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostpdm360ng.a
+LIB	= libpostpdm360ng.o
 
 COBJS-$(CONFIG_HAS_POST)	+= coproc_com.o
 
diff --git a/post/cpu/mpc83xx/Makefile b/post/cpu/mpc83xx/Makefile
index 86d8784ca5..a8b70059ff 100644
--- a/post/cpu/mpc83xx/Makefile
+++ b/post/cpu/mpc83xx/Makefile
@@ -22,7 +22,7 @@
 #
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostmpc83xx.a
+LIB	= libpostmpc83xx.o
 
 AOBJS-$(CONFIG_HAS_POST)	+=
 COBJS-$(CONFIG_HAS_POST)	+= ecc.o
diff --git a/post/cpu/mpc8xx/Makefile b/post/cpu/mpc8xx/Makefile
index 162924f6b2..3e1792f892 100644
--- a/post/cpu/mpc8xx/Makefile
+++ b/post/cpu/mpc8xx/Makefile
@@ -22,7 +22,7 @@
 #
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostmpc8xx.a
+LIB	= libpostmpc8xx.o
 
 AOBJS-$(CONFIG_HAS_POST)	+= cache_8xx.o
 COBJS-$(CONFIG_HAS_POST)	+= cache.o ether.o spr.o uart.o usb.o watchdog.o
diff --git a/post/cpu/ppc4xx/Makefile b/post/cpu/ppc4xx/Makefile
index 1cfd3bb59c..922013131f 100644
--- a/post/cpu/ppc4xx/Makefile
+++ b/post/cpu/ppc4xx/Makefile
@@ -22,7 +22,7 @@
 #
 include $(OBJTREE)/include/autoconf.mk
 
-LIB	= libpostppc4xx.a
+LIB	= libpostppc4xx.o
 
 AOBJS-$(CONFIG_HAS_POST)	+= cache_4xx.o
 COBJS-$(CONFIG_HAS_POST)	+= cache.o
diff --git a/post/drivers/Makefile b/post/drivers/Makefile
index 0b6cdf58c9..0d87ae0f9d 100644
--- a/post/drivers/Makefile
+++ b/post/drivers/Makefile
@@ -22,7 +22,7 @@
 #
 include $(TOPDIR)/config.mk
 
-LIB	= libpostdrivers.a
+LIB	= libpostdrivers.o
 
 COBJS-$(CONFIG_HAS_POST)	+= i2c.o memory.o rtc.o
 
diff --git a/post/lib_powerpc/Makefile b/post/lib_powerpc/Makefile
index 0cd15cfa13..bc9b82ef24 100644
--- a/post/lib_powerpc/Makefile
+++ b/post/lib_powerpc/Makefile
@@ -22,7 +22,7 @@
 #
 include $(TOPDIR)/config.mk
 
-LIB	= libpost$(ARCH).a
+LIB	= libpost$(ARCH).o
 
 AOBJS-$(CONFIG_HAS_POST)	+= asm.o
 COBJS-$(CONFIG_HAS_POST)	+= cpu.o cmp.o cmpi.o two.o twox.o three.o threex.o
diff --git a/post/lib_powerpc/fpu/Makefile b/post/lib_powerpc/fpu/Makefile
index 25726db73d..b97ad6fbc8 100644
--- a/post/lib_powerpc/fpu/Makefile
+++ b/post/lib_powerpc/fpu/Makefile
@@ -22,7 +22,7 @@
 #
 include $(TOPDIR)/config.mk
 
-LIB	= libpost$(ARCH)fpu.a
+LIB	= libpost$(ARCH)fpu.o
 
 COBJS-$(CONFIG_HAS_POST)	+= fpu.o 20001122-1.o 20010114-2.o 20010226-1.o 980619-1.o
 COBJS-$(CONFIG_HAS_POST)	+= acc1.o compare-fp-1.o mul-subnormal-single-1.o
diff --git a/post/rules.mk b/post/rules.mk
index 1efc9c7d97..17f8ef7623 100644
--- a/post/rules.mk
+++ b/post/rules.mk
@@ -34,7 +34,7 @@ CPPFLAGS += -I$(TOPDIR)
 all:	$(LIB)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 #########################################################################