Re: question about sysroot and Windows->Linux cross ld

[Joseph Myers <joseph at codesourcery dot com>]

On Wed, 17 Jan 2018, Carlos O'Donell wrote:

> My preference is that if you use the --sysroot that all paths must be
> rooted in the sysroot, but may fall back to non-sysroot lookups if the
> sysroot does not contain the files being searched. Note that I was
> used to working with --enable-poison-system-directories (out-of-tree
> patch) to prevent this, but I don't see it submitted anywhere, which
> is unfortunate.
> 
> Therefore I think there is a problem here, but it is unique to the linker
> script handling of paths not being sysrooted by default. I think they
> should be.

My understanding is that if the toolchain is configured 
--with-sysroot=<something> (both GCC and binutils configured that way), 
and if the libc.so linker script is found via a sysrooted path (*not* via 
an ordinary -L path), then the paths in it are automatically interpreted 
relative to the sysroot - and that this already works on Windows host 
without additional patches needed.  I've no idea about // paths, however 
(normally you configure glibc --prefix=/usr and shouldn't have // paths in 
the installed linker scripts), though I'd still expect those to be 
interpreted as sysroot-relative rather than as //host/mount/file paths.

It will *not* work if the libc.so linker script is found via a 
non-sysrooted path, and may not work if you use --sysroot= with a 
toolchain that wasn't configured to use a sysroot by default.

-- 
Joseph S. Myers
joseph@codesourcery.com