[binutils-gdb] PowerPC64 GOT reloc optimisation

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=06507dab6172582d3924a3d7dc92a9e7d4ab60ff

commit 06507dab6172582d3924a3d7dc92a9e7d4ab60ff
Author: Alan Modra <amodra@gmail.com>
Date:   Thu Apr 16 10:43:25 2020 +0930

    PowerPC64 GOT reloc optimisation
    
    When the symbol referenced by a GOT reloc is an ifunc, we can't
    optimise away the GOT indirection.  Well, we can, but only if a global
    entry stub is created with the ifunc symbol redefined to the stub.
    But that results in slower code and an indirection via the PLT so
    there isn't much to like about that solution.
    
            * elf64-ppc.c (ppc64_elf_edit_toc): Exclude ifunc from GOT
            optimisation.
            (ppc64_elf_relocate_section): Likewise.

Diff:
---
 bfd/elf64-ppc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 945f83c7e61..25a3e468a73 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -9371,6 +9371,9 @@ ppc64_elf_edit_toc (struct bfd_link_info *info)
 		  || discarded_section (sym_sec))
 		continue;
 
+	      if ((h ? h->type : ELF_ST_TYPE (sym->st_info)) == STT_GNU_IFUNC)
+		continue;
+
 	      if (!SYMBOL_REFERENCES_LOCAL (info, h))
 		continue;
 
@@ -15886,6 +15889,8 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	  break;
 
 	case R_PPC64_GOT16_DS:
+	  if ((h ? h->elf.type : ELF_ST_TYPE (sym->st_info)) == STT_GNU_IFUNC)
+	    break;
 	  from = TOCstart + htab->sec_info[input_section->id].toc_off;
 	  if (relocation + addend - from + 0x8000 < 0x10000
 	      && SYMBOL_REFERENCES_LOCAL (info, &h->elf))
@@ -15903,6 +15908,8 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 
 	case R_PPC64_GOT16_LO_DS:
 	case R_PPC64_GOT16_HA:
+	  if ((h ? h->elf.type : ELF_ST_TYPE (sym->st_info)) == STT_GNU_IFUNC)
+	    break;
 	  from = TOCstart + htab->sec_info[input_section->id].toc_off;
 	  if (relocation + addend - from + 0x80008000ULL < 0x100000000ULL
 	      && SYMBOL_REFERENCES_LOCAL (info, &h->elf))
@@ -15924,6 +15931,8 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	  break;
 
 	case R_PPC64_GOT_PCREL34:
+	  if ((h ? h->elf.type : ELF_ST_TYPE (sym->st_info)) == STT_GNU_IFUNC)
+	    break;
 	  from = (rel->r_offset
 		  + input_section->output_section->vma
 		  + input_section->output_offset);