C back-end: Passing struct by value fails

[waywardmonkeys]

This works with HARP, so we should examine the differences between the code.

This is needed for things with the Objective C bridge.

[fracek]

I have the same problem when returning a struct by value.

Test case to reproduce this:

typedef struct git_oid {
    unsigned char id[20];
} git_oid;

int my_function(git_oid *oid) {
    return 0;
}

and

define C-struct <git-oid>
  array slot git-oid$id :: <C-unsigned-char>, length: 20;
end;

define C-pointer-type <git-oid*> => <git-oid>;

define C-function my-function
  output parameter out_ :: <git-oid*>;
  result res :: <c-signed-int>;
  c-name: "my_function";
end;

define function main
    (name :: <string>, arguments :: <vector>)
  let (err, oid) = my-function();
  exit-application(0);
end function main;

stack trace:

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
No next method.
No next method.
Breaking into debugger.

Program received signal SIGTRAP, Trace/breakpoint trap.
0x00007ffff6b458cb in raise (sig=5) at ../nptl/sysdeps/unix/sysv/linux/pt-raise.c:37
37  ../nptl/sysdeps/unix/sysv/linux/pt-raise.c: No such file or directory.
(gdb) bt
#0  0x00007ffff6b458cb in raise (sig=5) at ../nptl/sysdeps/unix/sysv/linux/pt-raise.c:37
#1  0x00007ffff768a8b2 in primitive_invoke_debugger (string=<optimized out>, arguments=0x5) at /home/cek/Dev/opendylan/sources/lib/run-time/c-primitives-debug.c:38
#2  0x00007ffff75e9aee in Kinvoke_debuggerVKiMM1I (condition_=<optimized out>) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/boot.c:7112
#3  0x00007ffff75ef822 in Khandle_missed_dispatchVKgI (d_=<optimized out>, parent_=<optimized out>, args_=0x7fffffffbd40) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/new-dispatch.c:14394
#4  0x00007ffff7681a02 in general_engine_node_n_engine (a1=<optimized out>) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:2073
#5  0x00007ffff75fd451 in Kdefault_handlerVKdMM1I (condition_=0x4038) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/condition.c:2890
#6  0x00007ffff75ef822 in Khandle_missed_dispatchVKgI (d_=<optimized out>, parent_=<optimized out>, args_=0x7fffffffc1b0) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/new-dispatch.c:14394
#7  0x00007ffff7681a02 in general_engine_node_n_engine (a1=<optimized out>) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:2073
#8  0x00007ffff79a9962 in Kdefault_last_handlerYcommon_dylan_internalsVcommon_dylanMM0I (condition_=<optimized out>, next_handler_=0x6b7820)
    at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/common-extensions.c:1983
#9  0x00007ffff75fd2fd in KsignalVKdMM0I (condition_=0x6b5ea0, noise_=<optimized out>) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/condition.c:2712
#10 0x00007ffff75ef822 in Khandle_missed_dispatchVKgI (d_=<optimized out>, parent_=<optimized out>, args_=0x7fffffffcd50) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/new-dispatch.c:14394
#11 0x00007ffff7681a02 in general_engine_node_n_engine (a1=<optimized out>) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:2073
#12 0x00007ffff75fd5ab in KerrorVKdMM0I (condition_=0x6b5ea0, noise_=<optimized out>) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/condition.c:2631
#13 0x00007ffff75ef822 in Khandle_missed_dispatchVKgI (d_=<optimized out>, parent_=<optimized out>, args_=0x7fffffffd210) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/new-dispatch.c:14394
#14 0x00007ffff7681a02 in general_engine_node_n_engine (a1=<optimized out>) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:2073
#15 0x00007ffff75fd760 in KerrorVKdMM1I (string_=<optimized out>, arguments_=<optimized out>, arguments_=<optimized out>, string_=<optimized out>)
    at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/condition.c:2604
#16 0x00007ffff642957f in Kpointer_valueVKcMc_ffiM10I (ptr_=<optimized out>, Urest_=<optimized out>, index_=<optimized out>) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../c-ffi/pointer-value.c:1885
#17 0x00007ffff767ed61 in key_mep_3 (a1=<optimized out>) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:1683
#18 0x00007ffff76830d0 in implicit_keyed_single_method_engine_1 (a1=0x4038, optionals=0x202) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:2505
#19 0x00007ffff75ef822 in Khandle_missed_dispatchVKgI (d_=<optimized out>, parent_=<optimized out>, args_=0x7fffffffd820) at /home/cek/Desktop/test-c-struct/_build/build/test-c-struct/../common-dylan/../dylan/new-dispatch.c:14394
#20 0x00007ffff7681a02 in general_engine_node_n_engine (a1=<optimized out>) at /home/cek/Dev/opendylan/sources/lib/run-time/c-run-time.c:2073
#21 0x00007ffff7bdaf90 in Kmy_functionVtest_c_structI () at test-c-struct.c:916
#22 0x00007ffff7bdb14b in KmainVtest_c_structI (name_=<optimized out>, arguments_=<optimized out>) at test-c-struct.c:828
#23 _Init_test_c_struct__X_test_c_struct_for_user () at test-c-struct.c:1041
#24 0x00007ffff7deb85a in call_init (l=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7fffffffdda8, env=env@entry=0x7fffffffddb8) at dl-init.c:84
#25 0x00007ffff7deb943 in call_init (env=0x7fffffffddb8, argv=0x7fffffffdda8, argc=1, l=<optimized out>) at dl-init.c:36
#26 _dl_init (main_map=0x7ffff7ffe148, argc=1, argv=0x7fffffffdda8, env=0x7fffffffddb8) at dl-init.c:132
#27 0x00007ffff7dde1ca in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
#28 0x0000000000000001 in ?? ()
#29 0x00007fffffffe1fa in ?? ()
#30 0x0000000000000000 in ?? ()

This on 64 bit Linux, using a recent-ish master build.