[all-commits] [llvm/llvm-project] 459e8e: [PowerPC]: Don't allow r0 as a target for LD_GOT_T...

[Justin Hibbits via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 459e8e94886f979d079a9269dbb2ba83e84c4642
      https://github.com/llvm/llvm-project/commit/459e8e94886f979d079a9269dbb2ba83e84c4642
  Author: Justin Hibbits <jrh29 at alumni.cwru.edu>
  Date:   2020-03-26 (Thu, 26 Mar 2020)

  Changed paths:
    M llvm/lib/Target/PowerPC/PPCInstr64Bit.td
    M llvm/lib/Target/PowerPC/PPCInstrInfo.td
    M llvm/test/CodeGen/PowerPC/tls.ll

  Log Message:
  -----------
  [PowerPC]: Don't allow r0 as a target for LD_GOT_TPREL_L/32

Summary:
The linker is free to relax this (relocation R_PPC_GOT_TPREL16) against
R_PPC_TLS, if it sees fit (initial exec to local exec).  If r0 is used,
this can generate execution-invalid code (converts to 'addi %rX, %r0,
FOO, which translates in PPC-lingo to li %rX, FOO).  Forbid this
instead.

This fixes static binaries using locales on FreeBSD/powerpc
(tested on FreeBSD/powerpcspe).

Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D76662