C++ code on Jolt, full profiller support #1670

Hi,

I've been toying with running C++ code on Jolt. The full story is documented here.

tl;dr:

• I have a C++ ray tracer example running on Jolt VM. The guest program was built using clang / lld alone. I used a patched musl and libcxx so they are compatible with Jolt's ABI. I think this can serve as a different example in addition to Jolt's macro based approach.
• I noticed a slight discrepancy: the doc mentions termination address, MemoryLayout also has it, but writing to this address is actually a no-op, execution actually terminates with an infinite loop. My question is: is this just a coincidence? Will Jolt keep using the termination address, or be terminated just via j .?
• I understand that jolt has guest level profiling by explicitly marking a code section. I still believe a full program instrumentation path could be useful. So I built a simple module that converts Jolt's trace to a profiler usage format with multiple backends: flamegraphs, pprof and samply. I assume it might be useful for more. If you believe so I can start preparing it for upstream.

Let me know if you have any thoughts on the above points or the detailed post in general. Many thanks!