http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48835
--- Comment #8 from Mikael Pettersson <mikpe at it dot uu.se> 2011-06-11 12:33:09 UTC --- Created attachment 24491 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24491 patch fixing m68k function call abi issues in gnat WRT the the m68k function call ABI issues, I believe there are only a few cases where gnat does something which breaks m68k: - __gnat_malloc is defined in Ada to return Address (integer, so in d0), but it's called from a couple of places via fake "extern" declarations that pretend it returns void* (pointer, so in a0). The attached patch fixes the two call sites affected (in Interfaces.C.Strings and build_call_alloc_dealloc), as well as the internal fake prototype (init_gigi_decls). - Source code inspection showed that get_jmpbuf_address probably suffers from the same issue (mismatching decl and use via wrong intermediate fake prototype) so I fixed that too. There are a number of pointer-returning C library routines that are imported as-is with fake prototypes that declare them as returning Address. While wrong, this should work since the ABI returns pointers in both d0 and a0. With these fixes in place I can bootstrap gnat et al and the resulting binaries can be executed: aranym5_21_~/gnatroot/bin/gnat GNAT 4.4.7 20110419 (prerelease) Copyright 1996-2008, Free Software Foundation, Inc. List of available commands gnat bind gnatbind gnat chop gnatchop gnat clean gnatclean gnat compile gnatmake -f -u -c gnat check gnatcheck gnat sync gnatsync gnat elim gnatelim gnat find gnatfind gnat krunch gnatkr gnat link gnatlink gnat list gnatls gnat make gnatmake gnat metric gnatmetric gnat name gnatname gnat preprocess gnatprep gnat pretty gnatpp gnat stack gnatstack gnat stub gnatstub gnat xref gnatxref Commands find, list, metric, pretty, stack, stub and xref accept project file switches -vPx, -Pprj and -Xnam=val However, compiling the most trivial Ada program now fails with an assertion: aranym5_22_cat conftest.adb procedure conftest is begin null; end conftest; aranym5_23_~/gnatroot/bin/gcc -S conftest.adb +===========================GNAT BUG DETECTED==============================+ | 4.4.7 20110419 (prerelease) (m68k-unknown-linux-gnu) Assert_Failure einfo.adb:1748| | Error detected at system.ads:153:5 | | Please submit a bug report; see http://gcc.gnu.org/bugs.html. | | Use a subject line meaningful to you and us to track the bug. | | Include the entire contents of this bug box in the report. | | Include the exact gcc or gnatmake command that you entered. | | Also include sources listed below in gnatchop format | | (concatenated together with no headers between files). | +==========================================================================+ Please include these source files with error report Note that list may not be accurate in some cases, so please double check that the problem can still be reproduced with the set of files listed. conftest.adb compilation abandoned In case I missed some return value ABI fixups I hacked the m68k backend to return pointers in a0+d0 as before but always fetch them from d0, but it made no difference. The only potential issues I'm aware of now are endianess and alignment differences between the bootstrap host (i686-linux in my case) and m68k. That's because the bootstrap has to run the host's gnatmake a couple of times to generate the einfo/sinfo/etc thingys, which might not work correctly if the host and target have different endianess or alignment rules. Since I've bootstrapped gnat for big-endian ARM from little-endian i686 before, I don't think endianess is the problem, so I'm leaning towards m68k's unique alignment rules.
