Re: [yocto] Problem finding -lgcc when using SDK toolchain
On Wed, Oct 2, 2013 at 8:13 AM, Khem Raj wrote: > > On Oct 1, 2013, at 11:03 AM, Hans Beckerus wrote: > >> On 2013-10-01 7:35, Khem Raj wrote: >>> On Oct 1, 2013, at 6:16 AM, Hans Beckérus wrote: >>> Hello. We have stumbled into a problem when using ld directly instead of going through the gcc frontend. A simple operation like this fails: > ${CC} -c hello_world.c > ${LD} hello_world.o -lgcc arm-poky-linux-gnueabi-ld: cannot find -lgcc And yes, I know -lgcc is not required in this case to compile this one, but this is only a simple reproducer. The real issue was discovered when trying to build U-Boot from the SDK. To resolve this problem we are forced to provide -L/usr/lib/arm-poky-linux-gnueabi/4.7.2 to LDFLAGS. But that should not be needed, should it? Anyone else bumped into this problem? Are there any "real" solutions. I am starting to think it has to do with the hardcoded installation path in the binaries maybe? >>> I doubt that infact we try hard to keep it relocatable. The problem is you >>> are interpreting >>> --sysroot option to do more than what its supposed to do. when linking it >>> only affects INPUT, GROUP >>> and SEARCH_DIR linker script variables and if you look at the linker script >>> path to libgcc is not >>> specified in SEARCH_DIR, thats where gcc driver comes handy in figuring out >>> where the right libgcc is installed >>> and sometimes when you have complex multilib environments thats very handy. >>> linker does not know >>> anything about libgcc its just another library for it. >> Hi Khem, thanks for your time. I am sure I put too much value into >> --sysroot, but what still strikes me a bit odd is why the simple reproducer >> I showed before works just fine using the local host gcc and ld? It seems to >> have no issues in finding libgcc.a? > > Does it ? what distro are you using on build host. gcc -c hello.c;ld hello.o > -lgcc , does that work ? No, it does not. Whatever I tried before must have been wrong ;) > on my Ubuntu based system it fails exact same way as OE SDK, and for the > reasons I described > if you use bare ld to do linking then you can not assume it to resolve all > kind of environment for you > gcc driver is there for a reason. > >> So what you are saying is that it is actually expected that U-Boot build >> will fail when compiled through the SDK toolchain directly without adding >> additional options to the linker? Is that also what the u-boot recipe is >> doing? After all, it works fine to bitbake u-boot. > > No, the magic is in u-boot itself see in top level Makefile > > > PLATFORM_LIBGCC := -L $(shell dirname `$(CC) $(CFLAGS) > -print-libgcc-file-name`) -lgcc > Ok, but here is were it fails! The above call gets resolved to "-L .", and we do not have USE_PRIVATE_LIBGCC defined. Doing ${CC} -print-libgcc-file-name shows the proper value. The reason for this I now realize is that U-Boot does not pickup $CC from our environment (which is including the --sysroot option). Without this option -print-libgcc-file-name resolve to a simple file name without a path. And thus dirname resolve it further to "." :( So the fix for us is to do: >make LDFLAGS="" CC="$CC" Now it works. I assume that is also what the U-Boot recipe is doing. Thanks. Hans > > >> >>> however you could do something like >>> >>> ${CC} -print-libgcc-file-name or ${CC} -print-file-name=libgcc.a >>> >>> to get to the library >>> >>> and specify that in your linker cmdline >> Ok, guess it will simply give me the same path as we are currently >> hardcoding, but if the toolchain moves your solution is definitely to prefer. >> Thanks for the tip. Did only not know about the --print-sysroot command >> until now. >>> -Khem >> > ___ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
Re: [yocto] Problem finding -lgcc when using SDK toolchain
On Oct 1, 2013, at 11:03 AM, Hans Beckerus wrote: > On 2013-10-01 7:35, Khem Raj wrote: >> On Oct 1, 2013, at 6:16 AM, Hans Beckérus wrote: >> >>> Hello. We have stumbled into a problem when using ld directly instead >>> of going through the gcc frontend. >>> A simple operation like this fails: >>> ${CC} -c hello_world.c ${LD} hello_world.o -lgcc >>> arm-poky-linux-gnueabi-ld: cannot find -lgcc >>> >>> And yes, I know -lgcc is not required in this case to compile this >>> one, but this is only a simple reproducer. >>> The real issue was discovered when trying to build U-Boot from the SDK. >>> >>> To resolve this problem we are forced to provide >>> -L/usr/lib/arm-poky-linux-gnueabi/4.7.2 to LDFLAGS. >>> But that should not be needed, should it? Anyone else bumped into this >>> problem? Are there any "real" solutions. >>> I am starting to think it has to do with the hardcoded installation >>> path in the binaries maybe? >> I doubt that infact we try hard to keep it relocatable. The problem is you >> are interpreting >> --sysroot option to do more than what its supposed to do. when linking it >> only affects INPUT, GROUP >> and SEARCH_DIR linker script variables and if you look at the linker script >> path to libgcc is not >> specified in SEARCH_DIR, thats where gcc driver comes handy in figuring out >> where the right libgcc is installed >> and sometimes when you have complex multilib environments thats very handy. >> linker does not know >> anything about libgcc its just another library for it. > Hi Khem, thanks for your time. I am sure I put too much value into --sysroot, > but what still strikes me a bit odd is why the simple reproducer I showed > before works just fine using the local host gcc and ld? It seems to have no > issues in finding libgcc.a? Does it ? what distro are you using on build host. gcc -c hello.c;ld hello.o -lgcc , does that work ? on my Ubuntu based system it fails exact same way as OE SDK, and for the reasons I described if you use bare ld to do linking then you can not assume it to resolve all kind of environment for you gcc driver is there for a reason. > So what you are saying is that it is actually expected that U-Boot build will > fail when compiled through the SDK toolchain directly without adding > additional options to the linker? Is that also what the u-boot recipe is > doing? After all, it works fine to bitbake u-boot. No, the magic is in u-boot itself see in top level Makefile PLATFORM_LIBGCC := -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc > >> however you could do something like >> >> ${CC} -print-libgcc-file-name or ${CC} -print-file-name=libgcc.a >> >> to get to the library >> >> and specify that in your linker cmdline > Ok, guess it will simply give me the same path as we are currently > hardcoding, but if the toolchain moves your solution is definitely to prefer. > Thanks for the tip. Did only not know about the --print-sysroot command until > now. >> -Khem > ___ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
Re: [yocto] Problem finding -lgcc when using SDK toolchain
On 2013-10-01 7:35, Khem Raj wrote: > On Oct 1, 2013, at 6:16 AM, Hans Beckérus wrote: > >> Hello. We have stumbled into a problem when using ld directly instead >> of going through the gcc frontend. >> A simple operation like this fails: >> >>> ${CC} -c hello_world.c >>> ${LD} hello_world.o -lgcc >> arm-poky-linux-gnueabi-ld: cannot find -lgcc >> >> And yes, I know -lgcc is not required in this case to compile this >> one, but this is only a simple reproducer. >> The real issue was discovered when trying to build U-Boot from the SDK. >> >> To resolve this problem we are forced to provide >> -L/usr/lib/arm-poky-linux-gnueabi/4.7.2 to LDFLAGS. >> But that should not be needed, should it? Anyone else bumped into this >> problem? Are there any "real" solutions. >> I am starting to think it has to do with the hardcoded installation >> path in the binaries maybe? > I doubt that infact we try hard to keep it relocatable. The problem is you > are interpreting > --sysroot option to do more than what its supposed to do. when linking it > only affects INPUT, GROUP > and SEARCH_DIR linker script variables and if you look at the linker script > path to libgcc is not > specified in SEARCH_DIR, thats where gcc driver comes handy in figuring out > where the right libgcc is installed > and sometimes when you have complex multilib environments thats very handy. > linker does not know > anything about libgcc its just another library for it. Hi Khem, thanks for your time. I am sure I put too much value into --sysroot, but what still strikes me a bit odd is why the simple reproducer I showed before works just fine using the local host gcc and ld? It seems to have no issues in finding libgcc.a? So what you are saying is that it is actually expected that U-Boot build will fail when compiled through the SDK toolchain directly without adding additional options to the linker? Is that also what the u-boot recipe is doing? After all, it works fine to bitbake u-boot. > however you could do something like > > ${CC} -print-libgcc-file-name or ${CC} -print-file-name=libgcc.a > > to get to the library > > and specify that in your linker cmdline Ok, guess it will simply give me the same path as we are currently hardcoding, but if the toolchain moves your solution is definitely to prefer. Thanks for the tip. Did only not know about the --print-sysroot command until now. > -Khem ___ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
Re: [yocto] Problem finding -lgcc when using SDK toolchain
On Oct 1, 2013, at 6:16 AM, Hans Beckérus wrote: > Hello. We have stumbled into a problem when using ld directly instead > of going through the gcc frontend. > A simple operation like this fails: > >> ${CC} -c hello_world.c >> ${LD} hello_world.o -lgcc > arm-poky-linux-gnueabi-ld: cannot find -lgcc > > And yes, I know -lgcc is not required in this case to compile this > one, but this is only a simple reproducer. > The real issue was discovered when trying to build U-Boot from the SDK. > > To resolve this problem we are forced to provide > -L/usr/lib/arm-poky-linux-gnueabi/4.7.2 to LDFLAGS. > But that should not be needed, should it? Anyone else bumped into this > problem? Are there any "real" solutions. > I am starting to think it has to do with the hardcoded installation > path in the binaries maybe? I doubt that infact we try hard to keep it relocatable. The problem is you are interpreting --sysroot option to do more than what its supposed to do. when linking it only affects INPUT, GROUP and SEARCH_DIR linker script variables and if you look at the linker script path to libgcc is not specified in SEARCH_DIR, thats where gcc driver comes handy in figuring out where the right libgcc is installed and sometimes when you have complex multilib environments thats very handy. linker does not know anything about libgcc its just another library for it. however you could do something like ${CC} -print-libgcc-file-name or ${CC} -print-file-name=libgcc.a to get to the library and specify that in your linker cmdline -Khem ___ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
[yocto] Problem finding -lgcc when using SDK toolchain
Hello. We have stumbled into a problem when using ld directly instead of going through the gcc frontend. A simple operation like this fails: >${CC} -c hello_world.c >${LD} hello_world.o -lgcc arm-poky-linux-gnueabi-ld: cannot find -lgcc And yes, I know -lgcc is not required in this case to compile this one, but this is only a simple reproducer. The real issue was discovered when trying to build U-Boot from the SDK. To resolve this problem we are forced to provide -L/usr/lib/arm-poky-linux-gnueabi/4.7.2 to LDFLAGS. But that should not be needed, should it? Anyone else bumped into this problem? Are there any "real" solutions. I am starting to think it has to do with the hardcoded installation path in the binaries maybe? If you choose not to install the SDK where Yocto assumes it to be installed things break, even if --sysroot is used. Thanks. Hans ___ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto