Cosmo will now print C++ symbols correctly in --ftrace logs and
backtraces. Doing this required reducing the memory requirement
of the __demangle() function by 3x. This was accomplished using
16-bit indices and 16-bit malloc granularity. That puts a limit
on the longest symbol we can successfully decode, which I think
would be around 6553 characters long, given a 65536-byte buffer
We're now able to pretty print a C++ backtrace upon crashing in pretty
much any runtime execution scenario. The default pledge sandbox policy
on Linux is now to return EPERM. If you call pledge and have debugging
functions linked (e.g. GetSymbolTable) then the symbol table shall get
loaded before any security policy is put in place. This change updates
build/bootstrap/fixupobj too and fixes some other sneaky build errors.
It's now possible to safely print C++ backtraces from signal handlers.
This symbol demangler doesn't need malloc, tls, or even static memory.
Additionally, this change makes it 2x faster and adds test cases. It's
almost as performant and accurate as the libcxxabi implementation now.
