> On 29 Aug 2017, at 09:56, Rainer Orth <r...@cebitec.uni-bielefeld.de> wrote:
>>> 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.). It's been unsupported in user-space for as long as I recall … > 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. possibly, indeed - but ... … as noted above. when bringing the system up from scratch (i.e. bootstrapping the kernel, and associated stuff) there’s (or at least used to be) a phase where some tools _are_ built with static linkage - and part of that process involves building the crt0 + a statically-linkable libc. That the code is still present in clang, suggests this could still be the case (although the ‘just left in there by accident’ explanation is possible too, I will try to query someone for a definite answer). In any case, we might as well just skip such tests (or xfail them) on Darwin, that’s a correct reflection of the user-land expectation. Iain Sandoe CodeSourcery / Mentor Embedded / Siemens
