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Re: libgcc not built?

On 3/31/19 10:39 PM, matthew green wrote:
Yann Sionneau writes:
Hello Matthew,

Thanks for your answer :)

Is src/tools/gcc/README.mknative relevant for my cross compilation
Or only for a *native* (host=lm32 target=lm32) toolchain?
you need libgcc from somewhere.  typically that comes from
base netbsd, but for brand new ports with no in-tree help
it may come from the $EXTERNAL_TOOLCHAIN.  for new ports
using base gcc, we typically use libgcc built normally,
but if you don't want a host compiler, MKGCCCMDS=no is
supported (and default, on eg sun2.)

which compiler are you using?

I am using the cross compiler built by ./ -m milkymist -u -U tools

It seems that when it builds the cross compiler, it does not build the libgcc.

How am I supposed to make the build system generate libgcc?

I use MKGCCCMDS=no when I run the "build" target (./ -m milkymist -u -U build).

Maybe I should use it also for the "tools" target?

For now I am only building a cross toolchain and I don't plan on
building a native one.

I'm trying to see how those parts plug together.

IIUC, the kernel only links with libkern and does not need libgcc (but
some symbols which usually are in libgcc need to be put in libkern).
libkern implements the parts of libgcc that are required
by the compiler itself -- run time routines for common
operations.  so typically we have to reimplement them in
libkern to use the compiler.
For the user space the picture is a bit blury for me.

I guess I need to consider two cases: statically linked programs, and
dynamically linked ones.
you'll need to deal with both eventually, but if you want
to just start with static for now that's an option.





Le 31/03/2019 à 20:43, matthew green a écrit :
Yann Sionneau writes:

Yesterday I had a look at my lm32 NetBSD port (which is stalled since
2014 for lack of time).

And I noticed that I cannot link user space binaries because the built
cross toolchain lacks libgcc.

I wonder: why is libgcc not built?

Any guru of NetBSD/gcc build system could tell me? I didn't find
anything obvious but I'm not a pro on this.
hi Yann,

this is entirely on purpose.  we don't use libgcc built out of the
toolchain tree as it has a chicken/egg problem with shared libraries
and configure.  the netbsd toolchain does not include any parts that
are shipped -- it merely builds it.

you may want to look at src/tools/gcc/README.mknative and look at
the bootstrap libgcc parts.

feel free to ask more questions -- mknative is difficut to get
bootstrapped (worse than it was, for sure.)


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