NFC: Add fprint variants of internal print functions

[topolarity]

This adds/changes a number of fprint_* variants to internal debug functions:

• rename + new ios_t * argument:
  • jl_critical_error -> jl_fprint_critical_error
  • jl_print_native_codeloc -> jl_fprint_native_codeloc
  • jl_print_bt_entry_codeloc -> jl_fprint_bt_entry_codeloc
  • jl_gc_debug_print_status -> jl_gc_debug_fprint_status
  • jl_gc_debug_critical_error -> jl_gc_debug_fprint_critical_error
• new fprint_* variants:
  • jl_safe_fprintf
  • jl_safe_static_show
  • jl_fprint_backtrace(t)

Note that care needs to be taken w.r.t. what ios_t * value is passed into these functions from within a signal handler on Unix. Memory allocation is not async-signal-safe, so the ios_t needs to wrap a raw fd_t handle.

Immediate motivation is #54836

[vtjnash]

I started to try to rebase this, but then noticed that it changed jl_safe_printf (to STDERR_FILENO) into jl_unsafe_printf (to ios_stderr), which is very much not NFC.

[topolarity]

Is that not covered by:

Note that care needs to be taken w.r.t. what ios_t * value is passed into these functions from within a signal handler on Unix.
Memory allocation is not async-signal-safe, so the ios_t needs to wrap a raw fd_t handle.

[vtjnash]

Ah, I guess that is true. But you're assuming that ios_t is async-signal-safe, which is only true in bm_none mode or if locally created. Do you want to rebase it then, but use ios_t safe_stderr = ios_fd(&safe_stderr, STDERR_FILENO, 0, 0); safe_stderr->bm = bm_none; ios_close(&safe_stderr), where applicable to make it NFC?

[vtjnash]

I guess actually bm_line might be a better choice also (should give much faster jl_safe_printf, while still being somewhat robust against crashes)

[topolarity]

... use ios_t safe_stderr = ios_fd(&safe_stderr, STDERR_FILENO, 0, 0); safe_stderr->bm = bm_none; ios_close(&safe_stderr), where applicable to make it NFC?

No complaints here, but isn't that how it's already configured?

julia/src/support/ios.c

Lines 1074 to 1076 in f0ece4a

	ios_stderr = (ios_t*)malloc_s(sizeof(ios_t));
	ios_fd(ios_stderr, STDERR_FILENO, 0, 0);
	ios_stderr->bm = bm_none;

[vtjnash]

It is initialized that way, but that isn't the same as being configured that way arbitrarily later in the program. (and yes, that is where I copied that code from haha)

[fingolfin]

@topolarity I am now seeing this in "build x86_64-linux-gnummtk
" CI tests, not sure if related to this PR:

/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: ./builtins.o: in function `jl_f_intrinsic_call':
[buildroot]/src/builtins.c:2459: undefined reference to `jl_gc_debug_fprint_critical_error'
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: ./signal-handling.o: in function `jl_fprint_critical_error':
[buildroot]/src/signal-handling.c:652: undefined reference to `jl_gc_debug_fprint_status'
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: [buildroot]/src/signal-handling.c:653: undefined reference to `jl_gc_debug_fprint_critical_error'
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: ./task.o: in function `jl_finish_task':
[buildroot]/src/task.c:355: undefined reference to `jl_gc_debug_fprint_critical_error'
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: ./safepoint.o: in function `jl_safepoint_init':
[buildroot]/src/safepoint.c:109: undefined reference to `jl_gc_debug_fprint_critical_error'
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: ./rtutils.o: in function `__stack_chk_fail':
[buildroot]/src/rtutils.c:246: undefined reference to `jl_gc_debug_fprint_critical_error'
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: [buildroot]/usr/lib/libjulia-internal.so.1.13.0: hidden symbol `jl_gc_debug_fprint_status' isn't defined
/usr/local/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status
make[1]: *** [Makefile:449: [buildroot]/usr/lib/libjulia-internal.so.1.13.0] Error 1