[lld] r272915 - Early return. NFC.

[David Blaikie via llvm-commits]

On Thu, Jun 16, 2016 at 9:40 AM, Rui Ueyama via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: ruiu
> Date: Thu Jun 16 11:40:36 2016
> New Revision: 272915
>
> URL: http://llvm.org/viewvc/llvm-project?rev=272915&view=rev
> Log:
> Early return. NFC.
>
> Modified:
>     lld/trunk/ELF/Target.cpp
>
> Modified: lld/trunk/ELF/Target.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.cpp?rev=272915&r1=272914&r2=272915&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/Target.cpp (original)
> +++ lld/trunk/ELF/Target.cpp Thu Jun 16 11:40:36 2016
> @@ -1414,20 +1414,19 @@ void AArch64TargetInfo::relaxTlsIeToLe(u
>                                         uint64_t Val) const {
>    checkUInt<32>(Val, Type);
>
> -  uint32_t Inst = read32le(Loc);
> -  uint32_t NewInst;
>    if (Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21) {
> -    // Generate movz.
> -    unsigned RegNo = (Inst & 0x1f);
> -    NewInst = (0xd2a00000 | RegNo) | (((Val >> 16) & 0xffff) << 5);
> -  } else if (Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC) {
> -    // Generate movk
> -    unsigned RegNo = (Inst & 0x1f);
> -    NewInst = (0xf2800000 | RegNo) | ((Val & 0xffff) << 5);
> -  } else {
> -    llvm_unreachable("invalid Relocation for TLS IE to LE Relax");
> +    // Generate MOVZ.
> +    uint32_t RegNo = read32le(Loc) & 0x1f;
> +    write32le(Loc, (0xd2a00000 | RegNo) | (((Val >> 16) & 0xffff) << 5));
> +    return;
>    }
> -  write32le(Loc, NewInst);
> +  if (Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC) {
> +    // Generate MOVK.
> +    uint32_t RegNo = read32le(Loc) & 0x1f;
> +    write32le(Loc, (0xf2800000 | RegNo) | ((Val & 0xffff) << 5));
> +    return;
> +  }
> +  llvm_unreachable("invalid relocation for TLS IE to LE relaxation");
>

Generally we try not to branch-to-unreachable (which this unreachable sort
of is) & instead assert the inverse condition (replace the above 'if' with
an assert). But I realize that symmetry (if the code is a series of if
conditions) may be valuable & that's OK if you prefer it that way - just
thought I'd mention in case it suited.

- Dave


>  }
>
>  // Implementing relocations for AMDGPU is low priority since most
>
>
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