When we crash, emit a message straight away that says we're working
on a backtrace. If starting the backtracer fails, report that also.
Finally, add a duration to the messages output by the backtracer, so
that we can see how long it took.
rdar://118055527
There's no need for fatalError() to try to generate its own backtraces
when the runtime's backtracer is enabled. Not only is the code it uses
more fragile but it also doesn't support async or inline frames and it
can't look-up symbols properly either.
rdar://117470489
The `status` argument to the `_swift_backtrace_demangle()` function
isn't especially useful, won't match behaviour on Windows, and we
actually don't use it in the Swift code that calls this SPI.
Remove it.
rdar://110261712
Use the new module structure rather the old SwiftShims header. This
is much cleaner and lets us include operating system headers to get
the relevant definitions where possible.
Add code to support ELF and DWARF, including decompression using
zlib, zstd and liblzma if those turn out to be required and available.
rdar://110261712
This also adds a function to demangle a symbol, and a way for the
backtracing code to report warning messages to the same place as
the main runtime.
I'd like to rename the _swift_isThunkFunction() SPI also, but we
can't do that until we've made the changes to the _Backtracing
library, so we'll do that there instead.
rdar://110261430
Some symbolication frameworks have a symbol cache; we probably don't want
to use that for test cases, to avoid running into problems where the cache
holds stale information.
rdar://105409147
