[PATCH] Support for building using WSL (Windows Subsystem for Linux) on Windows (original) (raw)

Erik Joelsson erik.joelsson at oracle.com
Fri Dec 14 22:56:05 UTC 2018

On 2018-12-14 14:22, Magnus Ihse Bursie wrote:

Hi Erik,

I missed your comments a bit down in the message. Replies inline. On 2018-12-14 19:23, Erik Joelsson wrote: In configure today, we generate the SYSROOTCFLAGS but we do not use them in the configure script. Instead we rely on INCLUDE/LIB being set. This is of course not ideal, but having to set WSLENV=INCLUDE:LIB makes it more obvious. It would be better to append SYSROOTCFLAGS to CFLAGS for Cygwin and msys as well, but that change is not required for WSL to work. I see. I agree that we should change this behavior for all windows envs to use SYSROOTCFLAGS. But for now, I accept the WSLENV solution then.

Replacing the path works for Cygwin, but not for WSL. At least not the way we generate the VSPATH in this patch. The VSPATH will not inherit the PATH from the WSL environment as base, it will get the Windows PATH that was set before WSL was launched. We could perhaps improve the extraction logic to make this work better. See below.

* This is a question as much to Erik as to you: is it really correct to always rewrite VSPATH to unix style? (I'm talking about lines 470..486 in toolchainwindows.m4) I think not; this sounds like it will break cygwin. I think we should to this either conditionally on us running on WSL, or we should convert it to a VSWSLPATH instead. Or maybe I'm just missing something, I'm starting getting a bit confused about all these paths and conversions... In configure today, we do rewrite it, but it happens implicitly in the extraction script. The current version of the patch looks like what I posted. I will try to explain. In configure today, we generate extract-vs-env.bat, which end up containing lines like this (in cygwin): C:/cygwin64/bin/bash.exe -c 'echo VSPATH="$PATH" > set-vs-env.sh (note the unbalanced '. This is baffling me, but currently works in Cygwin.) ! :-o The bat file calls back to bash to evaluate the env variable. When I tried to get this to work for WSL, I had trouble getting the quoting to work. I had also forgotten about WSLENV so $PATH would not be translated, it would hold the default bash path, and for the other variables (INCLUDE and LIB) they simply did not get values in bash. My solution was to ditch bash here and just generate lines like this instead: echo VSPATH="%PATH%" > set-vs-env.sh This outputs the pure windows versions of the variables. For Cygwin, the old construct resulted in an implicitly converted PATH variable (though still with spaces!), but LIB and INCLUDE still pure windows. This is why we already have the conversion loops for those below. With the new construct, all variables remain pure Windows, which is arguably more consistent. So to work around now having pure windows paths in VSPATH, I added another rewrite loop. This is a bit inefficient, but has the benefit of generating space safe paths in VSPATH, which is a must if we are to prepend them to FIXPATH. I don't think we need to worry too much about efficiency in this case. We have a lot of inefficiencies in the path handling on Windows. The important thing is to get good and sane paths out of configure, so we can work with them easily in make. I just tried the patch on Cygwin and it isn't working. The new PATH variable we create this way does not contain /usr/bin, but instead /cygdrive/c/cygwin64/usr/bin, which doesn't actually exist. Cygwin fakes /usr/bin internally, but if it's expressed as a /cygdrive path this faking fails. The consequence is that make fails to find "gawk" later.

This variable extraction will need an overhaul before we can take i this patch.

/Erik

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