Panic when building zig compiler on Asahi Linux (Fedora), reached unreachable code

[ian-mcdowell]

Zig Version

0.12.0-dev.1859+27d4bf753

Steps to Reproduce and Observed Behavior

Hardware: Apple M2 Mac Mini
OS: Asahi Linux (Fedora Asahi Remix) from https://asahilinux.org/
Linux macmini 6.6.3-411.asahi.fc39.aarch64+16k #1 SMP PREEMPT_DYNAMIC Tue Dec 19 10:21:20 UTC 2023 aarch64 GNU/Linux

Packages:

• cmake: 3.27.7
• llvm, clang: 17.0.6-1

Steps:

• Clone zig's master branch
• mkdir build, cd build, cmake .., make install

Output:

admin@macmini:~/src/zig/build$ cmake ..
-- The C compiler identification is Clang 17.0.6
-- The CXX compiler identification is Clang 17.0.6
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring zig version 0.12.0-dev.1859+27d4bf753
-- Configuring done (0.5s)
-- Generating done (0.0s)
-- Build files have been written to: /home/admin/src/zig/build

admin@macmini:~/src/zig/build$ make install
[  5%] Building CXX object CMakeFiles/zigcpp.dir/src/zig_llvm.cpp.o
[ 10%] Building CXX object CMakeFiles/zigcpp.dir/src/zig_llvm-ar.cpp.o
[ 15%] Building CXX object CMakeFiles/zigcpp.dir/src/zig_clang.cpp.o
[ 21%] Building CXX object CMakeFiles/zigcpp.dir/src/zig_clang_driver.cpp.o
[ 26%] Building CXX object CMakeFiles/zigcpp.dir/src/zig_clang_cc1_main.cpp.o
[ 31%] Building CXX object CMakeFiles/zigcpp.dir/src/zig_clang_cc1as_main.cpp.o
[ 36%] Linking CXX static library zigcpp/libzigcpp.a
[ 36%] Built target zigcpp
[ 42%] Building C object CMakeFiles/zig-wasm2c.dir/stage1/wasm2c.c.o
[ 47%] Linking C executable zig-wasm2c
[ 47%] Built target zig-wasm2c
[ 52%] Converting /home/admin/src/zig/stage1/zig1.wasm to /home/admin/src/zig/build/zig1.c
[ 57%] Building C object CMakeFiles/zig1.dir/zig1.c.o
[ 63%] Building C object CMakeFiles/zig1.dir/stage1/wasi.c.o
[ 68%] Linking C executable zig1
[ 68%] Built target zig1
[ 73%] Running zig1.wasm to produce /home/admin/src/zig/build/zig2.c
[ 78%] Running zig1.wasm to produce /home/admin/src/zig/build/compiler_rt.c
[ 84%] Building C object CMakeFiles/zig2.dir/zig2.c.o
/home/admin/src/zig/build/zig2.c:3380249:8: warning: incompatible pointer types assigning to 'const uint16_t (*)[16]' (aka 'const unsigned short (*)[16]') from 'const uint16_t *' (aka 'const unsigned short *') [-Wincompatible-pointer-types]
 3380249 |    t26 = t25.ptr;
         |        ^ ~~~~~~~
1 warning generated.
[ 89%] Building C object CMakeFiles/zig2.dir/compiler_rt.c.o
[ 94%] Linking CXX executable zig2
[ 94%] Built target zig2
[100%] Building stage3
thread 9076 panic: reached unreachable code
Panicked during a panic. Aborting.
error: the following build command crashed:
/home/admin/src/zig/zig-cache/o/351d79e0b7578df85b0d682e567a514c/build /home/admin/src/zig/build/zig2 /home/admin/src/zig /home/admin/src/zig/zig-cache /home/admin/.cache/zig --seed 0xfb25c43 --prefix /home/admin/src/zig/build/stage3 --zig-lib-dir /home/admin/src/zig/lib -Dconfig_h=/home/admin/src/zig/build/config.h -Denable-llvm -Dno-langref -Dno-autodocs -Dtarget=native -Dcpu=native -Dversion-string=0.12.0-dev.1859+27d4bf753
make[2]: *** [CMakeFiles/stage3.dir/build.make:73: stage3/bin/zig] Error 1
make[1]: *** [CMakeFiles/Makefile2:196: CMakeFiles/stage3.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

Debugging with lldb:

admin@macmini:~/src/zig/build$ lldb ~/src/zig/zig-cache/o/351d79e0b7578df85b0d682e567a514c/build
(lldb) target create "/home/admin/src/zig/zig-cache/o/351d79e0b7578df85b0d682e567a514c/build"
Current executable set to '/home/admin/src/zig/zig-cache/o/351d79e0b7578df85b0d682e567a514c/build' (aarch64).
(lldb) process launch -- home/admin/src/zig/build/zig2 /home/admin/src/zig /home/admin/src/zig/zig-cache /home/admin/.cache/zig --seed 0xfb25c43 --prefix /home/admin/src/zig/build/stage3 --zig-lib-dir /home/admin/src/zig/lib -Dconfig_h=/home/admin/src/zig/build/config.h -Denable-llvm -Dno-langref -Dno-autodocs -Dtarget=native -Dcpu=native -Dversion-string=0.12.0-dev.1859+27d4bf753
Process 9110 launched: '/home/admin/src/zig/zig-cache/o/351d79e0b7578df85b0d682e567a514c/build' (aarch64)
thread 9110 panic: reached unreachable code
Panicked during a panic. Aborting.
Process 9110 stopped
* thread #1, name = 'build', stop reason = signal SIGABRT
    frame #0: 0x0000000000420294 build`os.linux.arm64.syscall4(number=rt_sigprocmask, arg1=2, arg2=281474976684104, arg3=0, arg4=8) at arm64.zig:55:5
   52   }
   53  
   54   pub fn syscall4(number: SYS, arg1: usize, arg2: usize, arg3: usize, arg4: usize) usize {
-> 55       return asm volatile ("svc #0"
   56           : [ret] "={x0}" (-> usize),
   57           : [number] "{x8}" (@intFromEnum(number)),
   58             [arg1] "{x0}" (arg1),
(lldb) bt
* thread #1, name = 'build', stop reason = signal SIGABRT
  * frame #0: 0x0000000000420294 build`os.linux.arm64.syscall4(number=rt_sigprocmask, arg1=2, arg2=281474976684104, arg3=0, arg4=8) at arm64.zig:55:5
    frame #1: 0x000000000041ff34 build`os.linux.sigprocmask(flags=2, set=0x0000ffffffff9848, oldset=0x0000000000000000) at linux.zig:1200:20
    frame #2: 0x00000000003d09b0 build`os.sigprocmask(flags=2, set=0x0000ffffffff9848, oldset=0x0000000000000000) at os.zig:5723:37
    frame #3: 0x00000000003d0924 build`os.raise(sig='\x06') at os.zig:631:20
    frame #4: 0x000000000036c774 build`os.abort at os.zig:573:14
    frame #5: 0x000000000036b6b0 build`debug.panicImpl(trace=0x0000000000000000, first_trace_addr=(data = 5164000, some = '\x01'), msg=(ptr = "reached unreachable code", len = 24)) at debug.zig:440:13
    frame #6: 0x00000000003551a0 build`builtin.default_panic(msg=(ptr = "reached unreachable code", len = 24), error_return_trace=0x0000000000000000, ret_addr=(data = 0, some = '\0')) at builtin.zig:819:32
    frame #7: 0x00000000004ecbe0 build`os.msync(memory=(ptr = "\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa", len = 4096), flags=1) at os.zig:4573:19
    frame #8: 0x00000000004783d8 build`debug.StackIterator.isValidMemory(address=281474976686528) at debug.zig:611:25
    frame #9: 0x0000000000426bf0 build`debug.StackIterator.next_internal(self=0x0000ffffffffb460) at debug.zig:696:77
    frame #10: 0x00000000003d929c build`debug.StackIterator.next(self=0x0000ffffffffb460) at debug.zig:589:41
    frame #11: 0x000000000041f7d8 build`debug.writeCurrentStackTrace__anon_17127(out_stream=io.writer.Writer(fs.File,error{SystemResources,DeviceBusy,Unexpected,AccessDenied,DiskQuota,NoSpaceLeft,FileTooBig,InputOutput,InvalidArgument,BrokenPipe,OperationAborted,NotOpenForWriting,LockViolation,WouldBlock,ConnectionResetByPeer},(function 'write')) @ 0x0000ffffffffb888, debug_info=0x0000000000727118, tty_config=io.tty.Config @ 0x0000ffffffffb8bf, start_addr=(data = 5164000, some = '\x01')) at debug.zig:736:19
    frame #12: 0x00000000003d0308 build`debug.dumpCurrentStackTrace(start_addr=(data = 5164000, some = '\x01')) at debug.zig:127:31
    frame #13: 0x000000000036b790 build`debug.panicImpl(trace=0x0000000000000000, first_trace_addr=(data = 5164000, some = '\x01'), msg=(ptr = "reached unreachable code", len = 24)) at debug.zig:421:38
    frame #14: 0x00000000003551a0 build`builtin.default_panic(msg=(ptr = "reached unreachable code", len = 24), error_return_trace=0x0000000000000000, ret_addr=(data = 0, some = '\0')) at builtin.zig:819:32
    frame #15: 0x00000000004ecbe0 build`os.msync(memory=(ptr = "", len = 4096), flags=1) at os.zig:4573:19
    frame #16: 0x00000000004783d8 build`debug.StackIterator.isValidMemory(address=281474976703760) at debug.zig:611:25
    frame #17: 0x0000000000426bf0 build`debug.StackIterator.next_internal(self=0x0000ffffffffc088) at debug.zig:696:77
    frame #18: 0x00000000003d929c build`debug.StackIterator.next(self=0x0000ffffffffc088) at debug.zig:589:41
    frame #19: 0x000000000037476c build`debug.captureStackTrace(first_address=<unavailable>, stack_trace=0x0000ffffffffc5a0) at debug.zig:295:29
    frame #20: 0x000000000035ab90 build`Build.Step.init(options=Build.Step.StepOptions @ 0x0000ffffffffc9a0) at Step.zig:162:40
    frame #21: 0x000000000035a16c build`Build.create(allocator=mem.Allocator @ 0x0000ffffffffd230, zig_exe=(ptr = "home/admin/src/zig/build/zig2", len = 27), build_root=Build.Cache.Directory @ 0x0000ffffffffd6f8, cache_root=Build.Cache.Directory @ 0x0000ffffffffd740, global_cache_root=Build.Cache.Directory @ 0x0000ffffffffd788, host=zig.system.NativeTargetInfo @ 0x0000ffffffffd4f8, cache=0x0000ffffffffd7d0, available_deps=[]Build.AvailableDeps__struct_4514 @ 0x0000ffffffffc760) at Build.zig:294:30
    frame #22: 0x0000000000364600 build`build_runner.main at build_runner.zig:76:41
    frame #23: 0x00000000003545fc build`start.posixCallMainAndExit [inlined] start.callMain at start.zig:585:37
    frame #24: 0x00000000003545f4 build`start.posixCallMainAndExit [inlined] start.initEventLoopAndCallMain at start.zig:519:5
    frame #25: 0x00000000003545f4 build`start.posixCallMainAndExit at start.zig:469:36
    frame #26: 0x0000000000354590 build`start.posixCallMainAndExit at start.zig:425:16
(lldb) 

Expected Behavior

I expect the compiler to be able to build on this platform.

[ian-mcdowell]

After digging further, I now see the discussion in #11308 and #16331, which this seems like a dupe of.