In 4 years the plugin wasn't adapted to other object formats. This patch
makes it specific for ELF, which will allow to remove some abstractions
down the line. It also moves the plugin from LLVMOrcJIT into
LLVMOrcDebugging, which didn't exist back then.
The `DebugObjectManagerPlugin` implements debugger support for ELF
platforms with the GDB JIT Interface. It emits a separate debug object
allocation in addition to the LinkGraph's own allocation. This used to
happen in the plugin's `notifyEmitted()` callback, i.e. after the
LinkGraph's allocation was finalized. In the meantime, it had to block
finalization of the corresponding materialization unit to make sure that
the debugger can register the object before the code runs.
This patch switches the plugin to use an allocation action instead. We
can remove the `notifyEmitted()` hook and implement all steps as JITLink
passes.
Allow C-API users to debug their JITed code via the GDB JIT Interface.
This is currently supported on ELF and MachO based platforms. On
other systems `LLVMOrcLLJITEnableDebugSupport()` returns an error.
This patch adds a new C-API header `LLJITUtils.h`, which can host
further advanced JIT features in the future. Using the header requires
linking against LLVMOrcDebugging.
This re-applies db51e572893, which was reverted in 05b1a2cb3e6 due to bot
failures. The DebuggerSupportPlugin now depends on DWARF, so it has been moved
to the new OrcDebugging library (as has the enableDebuggerSupport API).
