[PATCH] D14713: [ELF2] - Optimization for R_X86_64_GOTTPOFF relocation.

[George Rimar via llvm-commits]

grimar added inline comments.

================
Comment at: ELF/Target.cpp:375-378
@@ +374,6 @@
+  bool IsMovOp = *Instruct == 0x8b;
+  if (*Prefix == 0x4c)
+    *Prefix = IsMovOp ? 0x49 : 0x4D;
+  *Instruct = IsMovOp ? 0xc7 : 0x8d;
+  *RegSlot = IsMovOp ? (0xc0 | Reg) : (0x80 | Reg | (Reg << 3));
+  relocateOne(Loc, BufEnd, R_X86_64_TPOFF32, P, SA);
----------------
ruiu wrote:
> Does this handle SP register?
No. As I wrote in comments it will enlarge that code, but I can do that. Should I ?

================
Comment at: ELF/Target.cpp:379
@@ +378,3 @@
+  *RegSlot = IsMovOp ? (0xc0 | Reg) : (0x80 | Reg | (Reg << 3));
+  relocateOne(Loc, BufEnd, R_X86_64_TPOFF32, P, SA);
+}
----------------
ruiu wrote:
> I think the original code was better
> 
>   write32le(Loc, SA - Out<ELF64LE>::TlsPhdr->p_memsz);
According to manual its optimized exactly to R_X86_64_TPOFF32. Not sure how important skipped in that case OOR check as well:

```
case R_X86_64_TPOFF32:
    if (!isInt<32>(Val))
      error("R_X86_64_TPOFF32 out of range");
```


http://reviews.llvm.org/D14713