First step in reducing redundancy in `addRelocations()` implementations across ELF JITLink backends. The patch factors out common logic for ELF relocation traversal into the new helper function `forEachRelocation()` in the `ELFLinkGraphBuilder` base class. For now, this is applied to the Aarch64 implementation. Others may follow soon.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D109516
Set up basic infrastructure for 64-bit ARM architecture support in JITLink. It allows for loading a minimal object file and resolving a single relocation. Advanced features like GOT and PLT handling or relaxations were intentionally left out for the moment.
This patch follows the idea to keep implementations for ARM (32-bit) and Aaarch64 (64-bit) separate, because:
* it might be easier to share code with the MachO "arm64" JITLink backend
* LLVM has individual targets for ARM and Aaarch64 as well
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108986
Stefan Gränitz