On Wed, 22 Feb 2023, 09:02 Jonathan Wakely, <jwakely.gcc@xxxxxxxxx> wrote: > > > On Tue, 21 Feb 2023, 23:32 Josef Wolf, <jw@xxxxxxxxxxxxx> wrote: > >> Hello all, >> >> I am trying to build for a bare metal target without any OS support and I >> want >> to omit libc (newlib). >> > > > Do you mean you're trying to build GCC itself, or you're trying to build > your own program? > > > >> So I add >> >> -ffunction-sections -nostdlib -ffreestanding >> >> flags to assembler/compiler and >> >> -lnosys -nolibc -nodefaultlibs -nostartfiles -nostdlib -ffreestanding >> -static-libgcc -lgcc -lnosys -nolibc -nodefaultlibs -nostartfiles >> -nostdlib -ffreestanding -static-libgcc -lgcc >> >> to linker > > > Please show the full commands you're using > > If you add -v to the gcc command it will show exactly what it's doing. > Oh actually I see the problem. You're using -lgcc and your gcc was configured to use newlib, so libgcc depends on newlib. > > > > > > >> >> >> But gcc still tries to pull newlib: >> >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/bin/ld: >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/lib/thumb/v7e-m+fp/hard/libc.a(lib_a-init.o): >> in function `__libc_init_array': >> /var/tmp/builds/crossgcc/src/newlib-3.1.0/newlib/libc/misc/init.c:40: >> undefined reference to `_init' >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/bin/ld: >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/lib/thumb/v7e-m+fp/hard/libc.a(lib_a-sbrkr.o): >> in function `_sbrk_r': >> /var/tmp/builds/crossgcc/src/newlib-3.1.0/newlib/libc/reent/sbrkr.c:51: >> undefined reference to `_sbrk' >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/bin/ld: >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/lib/thumb/v7e-m+fp/hard/libc.a(lib_a-writer.o): >> in function `_write_r': >> /var/tmp/builds/crossgcc/src/newlib-3.1.0/newlib/libc/reent/writer.c:49: >> undefined reference to `_write' >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/bin/ld: >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/lib/thumb/v7e-m+fp/hard/libc.a(lib_a-closer.o): >> in function `_close_r': >> /var/tmp/builds/crossgcc/src/newlib-3.1.0/newlib/libc/reent/closer.c:47: >> undefined reference to `_close' >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/bin/ld: >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/lib/thumb/v7e-m+fp/hard/libc.a(lib_a-lseekr.o): >> in function `_lseek_r': >> /var/tmp/builds/crossgcc/src/newlib-3.1.0/newlib/libc/reent/lseekr.c:49: >> undefined reference to `_lseek' >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/bin/ld: >> /m/a/local/crossgcc/arm-none-eabi/bin/../lib/gcc/arm-none-eabi/9.3.0/../../../../arm-none-eabi/lib/thumb/v7e-m+fp/hard/libc.a(lib_a-readr.o): >> in function `_read_r': >> /var/tmp/builds/crossgcc/src/newlib-3.1.0/newlib/libc/reent/readr.c:49: >> undefined reference to `_read' >> collect2: error: ld returned 1 exit status >> >> So what is the magic option to tell gcc not to mess around with libc >> (newlib)? >> >> Thanks! >> >> >>
