> On 24 May 2022, at 4:22 pm, Ken Cunningham <ken.cunningham.web...@gmail.com>
> wrote:
>
>
>>
>> Does anyone know why things seem to be using rpath on arm64 builds
>
> Basically, it comes down to the fact that Apple has disallowed
> DYLD_LIBRARY_PATH to work on newer systems.
>
> gcc for Darwin has one developer working on it, practically. Iain. He has
> been maintaining it for 10+ years, wrote the objective C implementation it
> uses, and is pretty much the only reason gcc works on Darwin at all. Perhaps
> someone would fill his shoes if he stopped doing it, hard to say.
>
> He maintains hardware machines from 10.5 to the current, and he tries to keep
> as many versions of gcc as possible running on as many systems as he can.
>
> Once Apple disallowed DYLD_LIBRARY_PATH, he has had a lot of trouble running
> the test suites on the gcc libraries, as he can’t force the libraries under
> test to be the ones used. Instead the libraries installed are the ones used,
> which means he has to actually install the gcc before testing it.
>
> Multiply that by perhaps 6 active gcc versions on each system, and 50+ test
> runs of gcc weekly, and you can see the problem.
>
> Using @rpath gets around that problem very nicely.
>
> Now, LLVM and many other software projects have the same issue. They also use
> @rpath to do it. But on INSTALLATION these @rpaths can be rewritten
> automatically by cmake (or meson) to be full pathnames. So that is what
> MacPorts does.
>
> gcc’s build system does not currently offer that installation option. I don’t
> know how hard it would be to add it (any volunteers?) but for now at least,
> Iain is not keen on adding that @rpath rewrite-on-install business to gcc.
It probably would not be too to do to be honest. I do similar things in other
places where I need to alter binaries post destroot, using install-name-tool
etc. Recursively searching the destroot for all binaries and running some fix
up on them ? What, *precisely* would that fix need to be ? To ensure they have
an rpath entry for the place the binaries get installed, or something else ?
Chris
>
> So gcc is installing it’s libraries with the @rpath linkages — it’s not just
> arm, by the way. It’s just arm right now because that is the tip of the
> spear. Very soon ALL gcc installs will use @rpaths, as that is (for now,
> barring a better option) the only way Iain can maintain gcc at all on Darwin.
>
> Ken
>
>
