__builtin_debugtrap detection is wrong

[jwakely]

You use defined(__APPLE__) to decide whether to use __builtin_debugtrap but that's wrong, because only Clang supports that built-in, but GCC defines __APPLE__ too.

The minimal fix would be to just check defined(__clang__) instead of defined(__APPLE__).

I don't see any reason to restrict the use of __builtin_debugtrap() to aarch64 on macOS, you could use it on all platforms when compiling with Clang. For x86 it expands to int 3 which is what your own code does. For ARM it expands to .inst 0xe7f001f0 which is the same as your code again.

To use __builtin_debugtrap() whenever the compiler supports it, you can do something like:

#ifdef __has_builtin
# if __has_builtin(__builtin_debugtrap)
#  define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_BUILTIN_DEBUGTRAP
# endif
#endif

#ifndef DEBUG_BREAK_IMPL
// ... existing code ...
#endif

[ericoporto]

@jwakely do you have a fork with these fixes?

[jwakely]

No, maybe I'll create one tomorrow though

[dbabokin]

I got the same problem, when trying to use gcc on Apple ARM64 platform.

Checking defined(__clang__) instead or after defined(__APPLE__) would do the job.

The one can argue that using gcc on macOS is very strange use case. While tris is true, it has it's niche for building software in "Linux compatible mode" and it has its value for developers.

For the reference, I'm installing gcc through home brew: brew install gcc.