[PATCH] D46423: [WIP, RISCV] Support .option relax and .option norelax

[Lewis Revill via Phabricator via llvm-commits]

lewis-revill updated this revision to Diff 161490.
lewis-revill added a comment.

I've updated this revision to reflect the current state of what we're working with. The relax and norelax options work as intended with regards to enabling and disabling `R_RISCV_RELAX`. With this current patch, the behaviour of relocations is that if `.option relax` was ever parsed, then relocations are always generated. This is a safe approach which avoids incorrect codegen. Using the approach of only saving the STI state back to the backend when `.option relax` is parsed enables this behaviour. Other approaches might be a better fit, especially if any other future options need to save the state of the STI back to the backend, since this would invalidate the 'sticky bit' behaviour that we're looking for. I'll look into using the additional feature bit as you've suggested for this @shiva0217.


https://reviews.llvm.org/D46423

Files:
  include/llvm/MC/MCAsmBackend.h
  lib/MC/MCAsmStreamer.cpp
  lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.h
  lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.h
  test/MC/RISCV/option-invalid.s
  test/MC/RISCV/option-relax.s

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