Changes

Summary

  1. [ARM] implement support for ALU/LDR PC-relative group relocations (details)
Commit da66263b6e505a4c605efbe8d68c3b09ad3606a4 by ardb
[ARM] implement support for ALU/LDR PC-relative group relocations

Currently, LLD does not support the complete set of ARM group relocations.
Given that I intend to start using these in the Linux kernel [0], let's add
support for these.

This implements the group processing as documented in the ELF psABI. Notably,
this means support is dropped for very far symbol references that also carry a
small component, where the immediate is rotated in such a way that only part of
it wraps to the other end of the 32-bit word. To me, it seems unlikely that
this is something anyone could be relying on, but of course I could be wrong.

[0] https://lore.kernel.org/r/20211122092816.2865873-8-ardb@kernel.org/

Reviewed By: peter.smith, MaskRay

Differential Revision: https://reviews.llvm.org/D114172
The file was modifiedlld/test/ELF/arm-adr.s
The file was modifiedlld/test/ELF/arm-adr-err.s
The file was modifiedlld/test/ELF/arm-adr-long.s
The file was addedlld/test/ELF/arm-adr-err-long.s
The file was modifiedlld/ELF/Arch/ARM.cpp