GCCisms, and AT&T Assembly choke CLang

[vmlemon]

As an experiment, I tried to build the Orion userland with CLang/LLVM 8.0, for x86-64, and received the following output:

tyson@tyson-Lenovo-ideapad-120S-14IAP:~/Orion/user$ CC=clang make
make[1]: Entering directory '/home/tyson/Orion/user/lib'
make[2]: Entering directory '/home/tyson/Orion/user/lib/l4'
===> Making dependencies in .
clang: warning: -lssp: 'linker' input unused [-Wunused-command-line-argument]
===> debug.cc
clang -x c++ -I../../include -I../.. -I/usr/bin/../lib/gcc/x86_64-linux-gnu/8/include   -fno-stack-protector -nostdinc -g -O2 -m64 -mno-red-zone   -fno-stack-protector -lssp -O2 -g -Wall -Wshadow   -fno-stack-protector  -Wno-conversion -fno-exceptions -c debug.cc -o debug.o
clang: warning: -lssp: 'linker' input unused [-Wunused-command-line-argument]
In file included from debug.cc:31:
In file included from ../../include/l4/kip.h:35:
../../include/l4/types.h:379:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : l.raw + r };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:384:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : l.raw + r };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:389:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : l.raw + r.raw };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:394:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : l.raw - r };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:399:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : l.raw - r };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:404:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : l.raw - r.raw };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:410:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : c.raw + r };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:415:27: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    return (L4_Clock_t) { raw : c.raw - r };
                          ^~~~~
                          .raw = 
../../include/l4/types.h:521:13: warning: use of GNU old-style field designator extension [-Wgnu-designator]
            return L4_Never;
                   ^
../../include/l4/types.h:493:33: note: expanded from macro 'L4_Never'
#define L4_Never        ((L4_Time_t) { raw : 0UL })
                                       ^
../../include/l4/types.h:532:13: warning: use of GNU old-style field designator extension [-Wgnu-designator]
            return L4_Never;
                   ^
../../include/l4/types.h:493:33: note: expanded from macro 'L4_Never'
#define L4_Never        ((L4_Time_t) { raw : 0UL })
                                       ^
In file included from debug.cc:31:
In file included from ../../include/l4/kip.h:36:
In file included from ../../include/l4/amd64/syscalls.h:39:
../../include/l4/message.h:982:1: warning: all paths through this function will call itself [-Winfinite-recursion]
{
^
In file included from debug.cc:31:
In file included from ../../include/l4/kip.h:36:
../../include/l4/amd64/syscalls.h:168:19: error: unsupported inline asm: input with type 'L4_ThreadId_t' matching output with type 'L4_Word_t'
      (aka 'unsigned long')
        [spacespec]     "0" (SpaceSpecifier),   /* %5  RAX <- R8 */
                             ^~~~~~~~~~~~~~
../../include/l4/amd64/syscalls.h:220:15: error: unsupported inline asm: input with type 'L4_ThreadId_t' matching output with type 'L4_Word_t'
      (aka 'unsigned long')
        [dest]          "0" (dest)              /* %1  RDI */
                             ^~~~
../../include/l4/amd64/syscalls.h:261:15: error: unsupported inline asm: input with type 'L4_ThreadId_t' matching output with type 'L4_Word_t'
      (aka 'unsigned long')
        [dest]          "4" (dest)              /* %9  RDI */
                             ^~~~
../../include/l4/amd64/syscalls.h:315:15: error: unsupported inline asm: input with type 'L4_ThreadId_t' matching output with type 'L4_Word_t'
      (aka 'unsigned long')
        [from]          "3" (FromSpecifier),    /* %7  RDX */
                             ^~~~~~~~~~~~~
../../include/l4/amd64/syscalls.h:373:15: error: unsupported inline asm: input with type 'L4_ThreadId_t' matching output with type 'L4_Word_t'
      (aka 'unsigned long')
        [from]          "3" (FromSpecifier),    /* %7  RDX */
                             ^~~~~~~~~~~~~
../../include/l4/amd64/syscalls.h:463:18: error: unsupported inline asm: input with type 'L4_Fpage_t' matching output with type 'L4_Word_t'
      (aka 'unsigned long')
        [utcbarea]      "0" (UtcbArea),                 /* %5  RAX -> R8 */
                             ^~~~~~~~
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:260:49: warning: use of GNU old-style field designator extension [-Wgnu-designator]
        return L4_ExchangeRegisters (t, 0, 0, 0, 0, 0, L4_nilthread,
                                                       ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:285:49: warning: use of GNU old-style field designator extension [-Wgnu-designator]
        return L4_ExchangeRegisters (t, 0, 0, 0, 0, 0, L4_nilthread,
                                                       ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:304:59: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    (void) L4_ExchangeRegisters (t, (1 << 9), 0, 0, 0, 0, L4_nilthread,
                                                          ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:316:64: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    (void) L4_ExchangeRegisters (t, (1 << 6), 0, 0, 0, handle, L4_nilthread,
                                                               ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:338:59: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    (void) L4_ExchangeRegisters (t, (1 << 9), 0, 0, 0, 0, L4_nilthread,
                                                          ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:372:63: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    (void) L4_ExchangeRegisters (t, (1 << 8) + 6, 0, 0, 0, 0, L4_nilthread,
                                                              ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:383:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:396:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:422:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, &dummy, &dummy,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:438:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, sp, ip, flags,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:459:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, &dummy, &dummy,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:476:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, sp, ip, flags,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:499:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, &dummy, &dummy,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:517:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, sp, ip, flags,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:540:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, &dummy, &dummy,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:556:6: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                                 L4_nilthread, &state.raw, sp, ip, flags,
                                 ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:582:9: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                             L4_nilthread, HandlerThread, (void *) -1);
                             ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:588:9: warning: use of GNU old-style field designator extension [-Wgnu-designator]
                             L4_nilthread, InterruptThread, (void *) -1);
                             ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:595:76: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    L4_ExchangeRegisters (dest, L4_EXREGS_CTRLXFER_CONF_FLAG, 0, 0 , 0, 0, L4_nilthread,
                                                                           ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:604:76: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    L4_ExchangeRegisters (dest, L4_EXREGS_CTRLXFER_READ_FLAG, 0, 0 , 0, 0, L4_nilthread,
                                                                           ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
In file included from debug.cc:32:
In file included from ../../include/l4/tracebuffer.h:37:
../../include/l4/thread.h:613:77: warning: use of GNU old-style field designator extension [-Wgnu-designator]
    L4_ExchangeRegisters (dest, L4_EXREGS_CTRLXFER_WRITE_FLAG, 0, 0 , 0, 0, L4_nilthread,
                                                                            ^
../../include/l4/types.h:299:46: note: expanded from macro 'L4_nilthread'
#define L4_nilthread      ((L4_ThreadId_t) { raw : 0UL})
                                             ^
32 warnings and 6 errors generated.
make[2]: *** [../../Mk/l4.build.mk:58: debug.o] Error 1
make[2]: Leaving directory '/home/tyson/Orion/user/lib/l4'
make[1]: *** [../Mk/l4.subdir.mk:41: subdirs-all] Error 2
make[1]: Leaving directory '/home/tyson/Orion/user/lib'
make: *** [Mk/l4.subdir.mk:41: subdirs-all] Error 2
tyson@tyson-Lenovo-ideapad-120S-14IAP:~/Orion/user$ 

This probably isn't essential to fix, today, but it's something to be aware of, if I decide to invest more time into adding CLang support to the codebase.