Re: [testsuite, i386] Require -static support in gcc.dg/pie-static-[12].c (PR testsuite/81793)

[Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>]

Hi Iain,

>> All this begs the question why on earth would darwin.h (STARTFILE_SPEC)
>> accept -static and try to link libcrt0.o it the latter doesn't exist.
>> 
>> However, I've just found that the bundled clang on Darwin 11 does the
>> same (and fails in the same way: "ld: library not found for -lcrt0.o”).
>
> I think it’s because when one is bringing up the system, then one does (or
> at least used to) have a static libc/crt set.
> Thus the compiler did/does need to support it for that case.  I’ve not done
> a kernel bootstrap since ≈ Darwin9 era, so things might have changed and
> this could be history leaking through.

I've now found the following statement:

	https://developer.apple.com/library/content/qa/qa1118/_index.html

effectively declaring statically linked binaries unsupported (same as
newer Solaris versions do, btw.).

I've now checked clang from Darwin 17 (Xcode 9 Beta) and it behaves the
same.  I've found the following in clang sources

      } else {
        if (Args.hasArg(options::OPT_static) ||
            Args.hasArg(options::OPT_object) ||
            Args.hasArg(options::OPT_preload)) {
          CmdArgs.push_back("-lcrt0.o");

in lib/Driver/ToolChains/Darwin.cpp (Darwin::addStartObjectFileArgs).
Several comments seem to indicate that most of this is just a
straightforward translation of GCC's Darwin specs to C++ ;-)

Overall, mostly a historical artifact these days, it seems.

	Rainer

-- 
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Rainer Orth, Center for Biotechnology, Bielefeld University