How to Build Libgcc of GCC compiler

Question

Is there any way to build libgcc without building gcc compiler?

I have tried to run configure script of libgcc but it says ../../gcc/libgcc.mvars is missing.

My basic need is to build libgcc for multiple platforms with multiple configurations for various versions of libgcc.

Gram

Answer 1

Not reliably, because the GCC build system is quite monolithic and fragile.

The quickest way to get the libgcc's built is to configure and build with something like the following:

../gcc-src/configure --target=$TARGET --enable-languages=c
make all-target-libgcc
make install-target-libgcc

You might have to make all-gcc first, not sure if the dependencies are set up correctly.

Chromoprotein

consider platform A, 64-bit as host. Platform B defaults to 64-bit, but -m32 is supported. Any idea how to go about and build the libgcc for the -m32 target? Simply adding CFLAGS=-m32 to the make invocation would end up overwriting the original (-m64) libraries. – Abscond

@Abscond If you use --enable-multilib this may just work. I'm not sure though, as I have always built libgcc as part of the whole GCC thing. – Chromoprotein

yep, unfortunately that alone is not enough. There's more magic sauce needed, it seems. But thanks for taking the time to respond. – Abscond

@Abscond Essentially nothing stops you from configuring/building it twice, once with CC='gcc -m32' and once with CC='gcc -m64'... – Chromoprotein

Seems like you should use either --disable-multilib or --enable-multilib since it says "configure: error: I suspect your system does not have 32-bit development libraries (libc and headers). If you have them, rerun configure with --enable-multilib. If you do not have them, and want to build a 64-bit-only compiler, rerun configure with --disable-multilib." – Cunctation