The rust demangler has some odd buffer handling code, which will copy
the demangled string into the provided buffer, if it will fit.
Otherwise it uses the allocated buffer it made. But the length of the
incoming buffer will have come from a previous call, which was the
length of the demangled string -- not the buffer size. And of course,
we're unconditionally allocating a temporary buffer in the first
place. So we don't actually get buffer reuse, and we get a memcpy in
somecases.
However, nothing in LLVM ever passes in a non-null pointer. Neither
does anything pass in a status pointer that is then made use of. The
only exercise these have is in the test suite.
So let's just make the rust demangler have the same API as the dlang
demangler.
Reviewed By: tmiasko
Differential Revision: https://reviews.llvm.org/D123420
Add a demangling support for a small subset of a new Rust mangling
scheme, with complete support planned as a follow up work.
Intergate Rust demangling into llvm-cxxfilt and use llvm-cxxfilt for
end-to-end testing. The new Rust mangling scheme uses "_R" as a prefix,
which makes it easy to disambiguate it from other mangling schemes.
The public API is modeled after __cxa_demangle / llvm::itaniumDemangle,
since potential candidates for further integration use those.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D101444
Nathan Sidwell