Makefile: prevent libgcc to be linked twice

If we define USE_PRIVATE_LIBGCC, PLATFORM_LIBS is used during link. During this last link editing, libgcc may be listed twice and fail.
Prevent this using "filter-out" in top Makefile.

---
 Makefile |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

index 5db2e0e..4bdfe11 100644
@@ -311,7 +311,8 @@ endif
 else
 PLATFORM_LIBGCC = -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc
 endif
-PLATFORM_LIBS += $(PLATFORM_LIBGCC)
+PLATFORM_LIBS := $(PLATFORM_LIBGCC) \
+	$(filter-out %$(PLATFORM_LIBGCC), $(PLATFORM_LIBS))
 export PLATFORM_LIBS
 
 # Special flags for CPP when processing the linker script.

1.7.5.4

could you please provide more details ? libgcc should not be listed twice. -mike

On 10/17/2011 07:25 PM, Mike Frysinger :

I compile current u-boot with the flowing command line:
make -j5 CROSS_COMPILE=arm-linux-gnueabi- USE_PRIVATE_LIBGCC=yes at91sam9m10g45ek_nandflash

On an Ubuntu 11.10 with Linaro's cross-toolchain (targeting ARMv7). My SoC is an ARM926 so I use the "USE_PRIVATE_LIBGCC=yes" switch. This will prevent the build to take libgcc from my host but compile the u-boot embedded libgcc: everything is fine, good feature.

But, here is the final link editing stage:

UNDEF_SYM=`arm-linux-gnueabi-objdump -x board/atmel/at91sam9m10g45ek/libat91sam9m10g45ek.o api/libapi.o arch/arm/cpu/arm926ejs/at91/libat91.o arch/arm/cpu/arm926ejs/libarm926ejs.o arch/arm/lib/libarm.o common/libcommon.o disk/libdisk.o drivers/bios_emulator/libatibiosemu.o drivers/block/libblock.o drivers/dma/libdma.o drivers/fpga/libfpga.o drivers/gpio/libgpio.o drivers/hwmon/libhwmon.o drivers/i2c/libi2c.o drivers/input/libinput.o drivers/misc/libmisc.o drivers/mmc/libmmc.o drivers/mtd/libmtd.o drivers/mtd/nand/libnand.o drivers/mtd/onenand/libonenand.o drivers/mtd/spi/libspi_flash.o drivers/mtd/ubi/libubi.o drivers/net/libnet.o drivers/net/phy/libphy.o drivers/pci/libpci.o drivers/pcmcia/libpcmcia.o drivers/power/libpower.o drivers/rtc/librtc.o drivers/serial/libserial.o drivers/spi/libspi.o drivers/twserial/libtws.o drivers/usb/eth/libusb_eth.o drivers/usb/gadget/libusb_gadget.o drivers/usb/host/libusb_host.o drivers/usb/musb/libusb_musb.o drivers/usb/phy/libusb_phy.o dri vers/video/libvideo.o drivers/watchdog/libwatchdog.o fs/cramfs/libcramfs.o fs/ext2/libext2fs.o fs/fat/libfat.o fs/fdos/libfdos.o fs/jffs2/libjffs2.o fs/reiserfs/libreiserfs.o fs/ubifs/libubifs.o fs/yaffs2/libyaffs2.o lib/libfdt/libfdt.o lib/libgeneric.o lib/lzma/liblzma.o lib/lzo/liblzo.o lib/zlib/libz.o net/libnet.o post/libpost.o | sed -n -e 's/.*\(__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`; cd /home/nferre/workspace/u-boot/u-boot-git && arm-linux-gnueabi-ld -pie -T u-boot.lds -Bstatic -Ttext 0x73f00000 $UNDEF_SYM arch/arm/cpu/arm926ejs/start.o --start-group api/libapi.o arch/arm/cpu/arm926ejs/at91/libat91.o arch/arm/cpu/arm926ejs/libarm926ejs.o arch/arm/lib/libarm.o common/libcommon.o disk/libdisk.o drivers/bios_emulator/libatibiosemu.o drivers/block/libblock.o drivers/dma/libdma.o drivers/fpga/libfpga.o drivers/gpio/libgpio.o drivers/hwmon/libhwmon.o drivers/i2c/libi2c.o drivers/input/libinput.o drivers/misc/libmisc.o drivers/mmc/libmmc.o drivers/mtd/libmtd.o drivers/mtd/nand /libnand.o drivers/mtd/onenand/libonenand.o drivers/mtd/spi/libspi_flash.o drivers/mtd/ubi/libubi.o drivers/net/libnet.o drivers/net/phy/libphy.o drivers/pci/libpci.o drivers/pcmcia/libpcmcia.o drivers/power/libpower.o drivers/rtc/librtc.o drivers/serial/libserial.o drivers/spi/libspi.o drivers/twserial/libtws.o drivers/usb/eth/libusb_eth.o drivers/usb/gadget/libusb_gadget.o drivers/usb/host/libusb_host.o drivers/usb/musb/libusb_musb.o drivers/usb/phy/libusb_phy.o drivers/video/libvideo.o drivers/watchdog/libwatchdog.o fs/cramfs/libcramfs.o fs/ext2/libext2fs.o fs/fat/libfat.o fs/fdos/libfdos.o fs/jffs2/libjffs2.o fs/reiserfs/libreiserfs.o fs/ubifs/libubifs.o fs/yaffs2/libyaffs2.o lib/libfdt/libfdt.o lib/libgeneric.o lib/lzma/liblzma.o lib/lzo/liblzo.o lib/zlib/libz.o net/libnet.o post/libpost.o board/atmel/at91sam9m10g45ek/libat91sam9m10g45ek.o --end-group /home/nferre/workspace/u-boot/u-boot-git/arch/arm/lib/eabi_compat.o /home/nferre/workspace/u-boot/u-boot-git/arch/arm/lib /libgcc.o /home/nferre/workspace/u-boot/u-boot-git/arch/arm/lib/libgcc.o -Map u-boot.map -o u-boot

And you see that there is arch/arm/lib/libgcc.o included twice in object files that have to be linked together. I think that it is coming from the PLATFORM_LIBS variable so I modified like in my patch which solves the problem.

Best regards,

Nicolas Ferre

the issue shows up when using the board shortcut, and only when your tree is already configured. if you use at91sam9m10g45ek_nandflash_config and then another make, it works fine. if you start from a clean tree (git clean -x -d), it works fine.

this is due to PLATFORM_LIBS appending PLATFORM_LIBGCC when the tree has been configured, then exporting PLATFORM_LIBS, then the board shortcut running $(MAKE). the exported PLATFORM_LIBS gets LIBGCC appended a second time.

this issue will show up with any value that gets appended to PLATFORM_LIBS and not just libgcc. the arm code already hits this and deals with it locally. seems like we should instead unify this logic, or redo PLATFORM_LIBS so that it isn't an issue in the first place.
-mike

On 10/18/2011 06:06 PM, Mike Frysinger :

Ah thanks for the information. Indeed it is a more common way of using the configuration/compilation flow...

Yes, that it a bit confusing... But with proper explanation, we can deal with this.

Thanks for your help, best regards,

Nicolas Ferre