[PATCH] D47755: [RISCV] Insert R_RISCV_ALIGN relocation type and Nops for alignment when linker relaxation enabled

[Shiva Chen via Phabricator via llvm-commits]

shiva0217 created this revision.
shiva0217 added reviewers: asb, apazos.
Herald added subscribers: mgrang, edward-jones, zzheng, kito-cheng, niosHD, sabuasal, simoncook, johnrusso, rbar.

Linker relaxation may change code size. We need to fix up the alignment by inserting Nops and R_RISCV_ALIGN relocation type. So then linker could satisfy the alignment by removing Nops.

To do this:

1. Add insertNopBytesForAlignDirectiveInTextSection target hook to calculate the Nops we need to insert.
2. Add insertFixupForAlignDirectiveInTextSection target hook to insert the fixup type.


Repository:
  rL LLVM

https://reviews.llvm.org/D47755

Files:
  include/llvm/MC/MCAsmBackend.h
  lib/MC/MCAssembler.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
  lib/Target/RISCV/MCTargetDesc/RISCVFixupKinds.h
  test/MC/RISCV/align.s

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