https://github.com/llvm/llvm-project/pull/76236 introduced the forth
copy and it was time to deduplicate. This patch brings it back to 2,
one in OrcTargetProcess and one in legacy ExecutionEngine.
When lli runs the below IR, it emits in-memory debug objects and registers them with the GDB JIT interface. The tests dump and check the registered information. IR has limited ability to produce complex output in a portable way. Instead the tests rely on built-in functions implemented in lli. They use a new command line flag `-generate=function-name` to instruct the ORC JIT to expose the built-in function with the given name to the JITed program.
`debug-descriptor-elf-minimal.ll` calls `__dump_jit_debug_descriptor()` to reflect the list of debug entries issued for itself after emitting the main module. The output is textual and can be checked straight away.
`debug-objects-elf-minimal.ll` calls `__dump_jit_debug_objects()`, which instructs lli to walk through the list of debug entries and append the encountered in-memory objects to the program output. We feed this output into llvm-dwarfdump to parse the DWARF in each file and dump their structures.
We can do the same for JITLink once D97335 has landed.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D97694
