Re: [PATCH] gdb: recognize 64 bits Windows executables as Cygwin osabi

[Jon Turney <jon.turney@dronecode.org.uk>]

On 07/03/2020 17:45, Eli Zaretskii wrote:
>> Cc: gdb-patches@sourceware.org
>> From: Simon Marchi <simon.marchi@efficios.com>
>> Date: Sat, 7 Mar 2020 11:51:08 -0500
>>
>>    https://sourceware.org/ml/gdb-patches/2020-03/msg00151.html
>>
>> Currently, loading the 64-bits .exe in a GNU/Linux-hosted GDB ends up calling
>> the svr4 libraries code, which is plain wrong.  By using the Cygwin osabi,
>> at least the right shared libraries functions are used.
>>
>> I agree with what you suggest below, but I think that the current patch is
>> still a step forward and improves things.
> 
> I agree.  I just think we can do better.
> 
>> So what we can do is add an "MS-Windows" osabi and make "Cygwin" and
>> "MS-Windows" functionally equivalent.  Any "pei-i386" or "pei-x86-64"
>> executable would be detected as "MS-Windows".

I believe this suggestion for x86_64 is wrong, in the other direction:
x86_64 Cygwin is LP64, but Windows is LLP64 (Se also table in [1])

(currently 'print sizeof(long)' incorrectly returns 4 on a gdb built for 
Cygwin)

There was some discussion that these need to be separate osabis 
previously, I think.

[1] https://cygwin.com/faq.html#faq.programming.64bitporting

> That's fine with me, and IMO will be more accurate than calling them
> all "Cygwin", since Cygwin programs are just a peculiar kind of
> Windows executables.
> 
>> If we do such a change, I would like it to be done on top of the current
>> patch, as to not mix concerns.
> 
> I'm okay with that, thanks.