[fpc-devel] Cross-compiling and warnings from linker

[Sergey Organov]

Jonas Maebe via fpc-devel
<fpc-devel-PD4FTy7X32k2wBtHl531yWD2FQJk+8+b at public.gmane.org> writes:

> On 21/11/2021 20:51, Sergey Organov via fpc-devel wrote:
>> Then, in the /etc/fpc.cfg file, among a lot of statements inappropriate
>> for cross-compilation (that happen to do no harm in my case), that is
>> only expected for the file that belongs to installed native compiler,
>> there is unconditional
>> -Fl/usr/lib/$fpctarget-*
>> directive that causes all this noise due to another bug, see below.
>
> This one needs to become -Fl=/usr/lib/$fpctarget-* (see
> https://wiki.freepascal.org/User_Changes_3.2.0#Library_search_directories_and_custom_sysroots
> )

Yeah, I see. However, this file (/etc/fpc.cfg) is part of installation
of particular version of FPC provided by corresponding Linux
distribution, and is out of control of a person that installs custom
(likely more recent) FPC. That's just yet another reason not to read
/etc/fpc.cfg unless compiler is installed in /usr/, more so as different
FPC versions may have incompatible ideas of its meaning.

[...]

>> Further, even for a native compiler being installed, say, in /usr/local,
>> the fpc.cfg should probably be searched for in /usr/local/etc rather
>> than in /etc,so the policy of searching for fpc.cfg should probably be
>> revised in general.
>
> It is indeed possible to argue for this, but that would be a
> significant backward compatibility breakage and I'm not sure it would
> be worth it.

Yep, backward compatibility could be an issue. A solution could be to
still read /etc/fpc.cfg if /usr/local/etc/fpc.cfg is not found.

>
>> 3. This is unrelated to the issue, but worth to be mentioned anyway. For
>> whatever reason, -XR causes FPC to alter its strategy with respect to
>> creation of the link.res file, and instead of augmenting of what is
>> already there in GNU ld for given target, it entirely replaces GNU ld
>> idea of suitable linker script with some outdated version of one being
>> built-in into FPC. I failed to guess what's the reason for it, so I tend
>> to think it's a design mistake.
>
> This has been fixed in trunk already. It was originally done that way
> because older versions of GNU LD did not support augmentation of
> built-in linker scripts, only replacing them wholesale. When we
> initially added support for GNU LD versions that did support
> augmentation, it was only implemented for native targets. Only more
> recently someone checked that it indeed also works correctly for
> cross-compiling and it was changed there as well.

Ah, now I see, thanks for clarification!

-- Sergey Organov