Fix performance regression due to ld -r memmove

The idea here is that instead of using memmove to shuffle the relocs
array every time one is deleted, to add a "wrel" pointer and copy from
rel[0] to wrel[0] as we go.

	* elf64-ppc.c (ppc64_elf_relocate_section): Use read and write
	pointers to reloc array, rather than memmove when deleting a
	reloc.  Don't use RELOC_AGAINST_DISCARDED_SECTION.  Adjust
	reloc counts at end of loop.
	* elf32-ppc.c (ppc_elf_relocate_section): Likewise.

1 files changed, 66 insertions, 30 deletions

diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 0a85ab8..f491a09 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -13162,6 +13162,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
   Elf_Internal_Shdr *symtab_hdr;
   struct elf_link_hash_entry **sym_hashes;
   Elf_Internal_Rela *rel;
+  Elf_Internal_Rela *wrel;
   Elf_Internal_Rela *relend;
   Elf_Internal_Rela outrel;
   bfd_byte *loc;
@@ -13193,9 +13194,9 @@ ppc64_elf_relocate_section (bfd *output_bfd,
   sym_hashes = elf_sym_hashes (input_bfd);
   is_opd = ppc64_elf_section_data (input_section)->sec_type == sec_opd;
 
-  rel = relocs;
+  rel = wrel = relocs;
   relend = relocs + input_section->reloc_count;
-  for (; rel < relend; rel++)
+  for (; rel < relend; wrel++, rel++)
     {
       enum elf_ppc64_reloc_type r_type;
       bfd_vma addend;
@@ -13219,10 +13220,13 @@ ppc64_elf_relocate_section (bfd *output_bfd,
       struct ppc_stub_hash_entry *stub_entry;
       bfd_vma max_br_offset;
       bfd_vma from;
-      const Elf_Internal_Rela orig_rel = *rel;
+      Elf_Internal_Rela orig_rel;
       reloc_howto_type *howto;
       struct reloc_howto_struct alt_howto;
 
+    again:
+      orig_rel = *rel;
+
       r_type = ELF64_R_TYPE (rel->r_info);
       r_symndx = ELF64_R_SYM (rel->r_info);
 
@@ -13230,10 +13234,10 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	 symbol of the previous ADDR64 reloc.  The symbol gives us the
 	 proper TOC base to use.  */
       if (rel->r_info == ELF64_R_INFO (0, R_PPC64_TOC)
-	  && rel != relocs
-	  && ELF64_R_TYPE (rel[-1].r_info) == R_PPC64_ADDR64
+	  && wrel != relocs
+	  && ELF64_R_TYPE (wrel[-1].r_info) == R_PPC64_ADDR64
 	  && is_opd)
-	r_symndx = ELF64_R_SYM (rel[-1].r_info);
+	r_symndx = ELF64_R_SYM (wrel[-1].r_info);
 
       sym = NULL;
       sec = NULL;
@@ -13314,13 +13318,27 @@ ppc64_elf_relocate_section (bfd *output_bfd,
       h = (struct ppc_link_hash_entry *) h_elf;
 
       if (sec != NULL && discarded_section (sec))
-	RELOC_AGAINST_DISCARDED_SECTION (info, input_bfd, input_section,
-					 rel, 1, relend,
-					 ppc64_elf_howto_table[r_type], 0,
-					 contents);
+	{
+	  _bfd_clear_contents (ppc64_elf_howto_table[r_type],
+			       input_bfd, input_section,
+			       contents + rel->r_offset);
+	  wrel->r_offset = rel->r_offset;
+	  wrel->r_info = 0;
+	  wrel->r_addend = 0;
+
+	  /* For ld -r, remove relocations in debug sections against
+	     sections defined in discarded sections.  Not done for
+	     non-debug to preserve relocs in .eh_frame which the
+	     eh_frame editing code expects to be present.  */
+	  if (bfd_link_relocatable (info)
+	      && (input_section->flags & SEC_DEBUGGING))
+	    wrel--;
+
+	  continue;
+	}
 
       if (bfd_link_relocatable (info))
-	continue;
+	goto copy_reloc;
 
       if (h != NULL && &h->elf == htab->elf.hgot)
 	{
@@ -13480,10 +13498,12 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	      && (tls_mask & TLS_TPREL) == 0)
 	    {
 	    toctprel:
-	      insn = bfd_get_32 (output_bfd, contents + rel->r_offset - d_offset);
+	      insn = bfd_get_32 (output_bfd,
+				 contents + rel->r_offset - d_offset);
 	      insn &= 31 << 21;
 	      insn |= 0x3c0d0000;	/* addis 0,13,0 */
-	      bfd_put_32 (output_bfd, insn, contents + rel->r_offset - d_offset);
+	      bfd_put_32 (output_bfd, insn,
+			  contents + rel->r_offset - d_offset);
 	      r_type = R_PPC64_TPREL16_HA;
 	      if (toc_symndx != 0)
 		{
@@ -13491,8 +13511,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		  rel->r_addend = toc_addend;
 		  /* We changed the symbol.  Start over in order to
 		     get h, sym, sec etc. right.  */
-		  rel--;
-		  continue;
+		  goto again;
 		}
 	      else
 		rel->r_info = ELF64_R_INFO (r_symndx, r_type);
@@ -13518,8 +13537,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		  rel->r_addend = toc_addend;
 		  /* We changed the symbol.  Start over in order to
 		     get h, sym, sec etc. right.  */
-		  rel--;
-		  continue;
+		  goto again;
 		}
 	      else
 		rel->r_info = ELF64_R_INFO (r_symndx, r_type);
@@ -13658,8 +13676,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		{
 		  /* We changed the symbol.  Start over in order
 		     to get h, sym, sec etc. right.  */
-		  rel--;
-		  continue;
+		  goto again;
 		}
 	    }
 	  break;
@@ -13703,10 +13720,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		}
 	      bfd_put_32 (output_bfd, insn2, contents + offset);
 	      if ((tls_mask & TLS_TPRELGD) == 0 && toc_symndx != 0)
-		{
-		  rel--;
-		  continue;
-		}
+		goto again;
 	    }
 	  break;
 
@@ -13748,8 +13762,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		  insn2 = NOP;
 		}
 	      bfd_put_32 (output_bfd, insn2, contents + offset);
-	      rel--;
-	      continue;
+	      goto again;
 	    }
 	  break;
 
@@ -14091,7 +14104,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		   && addend == 0)
 	    {
 	      bfd_put_32 (output_bfd, NOP, contents + rel->r_offset);
-	      continue;
+	      goto copy_reloc;
 	    }
 	  break;
 	}
@@ -14107,7 +14120,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 
 	  bfd_set_error (bfd_error_bad_value);
 	  ret = FALSE;
-	  continue;
+	  goto copy_reloc;
 
 	case R_PPC64_NONE:
 	case R_PPC64_TLS:
@@ -14116,7 +14129,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	case R_PPC64_TOCSAVE:
 	case R_PPC64_GNU_VTINHERIT:
 	case R_PPC64_GNU_VTENTRY:
-	  continue;
+	  goto copy_reloc;
 
 	  /* GOT16 relocations.  Like an ADDR16 using the symbol's
 	     address in the GOT as relocation value instead of the
@@ -14752,7 +14765,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 
 	  bfd_set_error (bfd_error_invalid_operation);
 	  ret = FALSE;
-	  continue;
+	  goto copy_reloc;
 	}
 
       /* Multi-instruction sequences that access the TOC can be
@@ -14901,7 +14914,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 		 mask + 1);
 	      bfd_set_error (bfd_error_bad_value);
 	      ret = FALSE;
-	      continue;
+	      goto copy_reloc;
 	    }
 	  break;
 	}
@@ -15000,6 +15013,29 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	  if (more_info != NULL)
 	    free (more_info);
 	}
+    copy_reloc:
+      if (wrel != rel)
+	*wrel = *rel;
+    }
+
+  if (wrel != rel)
+    {
+      Elf_Internal_Shdr *rel_hdr;
+      size_t deleted = rel - wrel;
+
+      rel_hdr = _bfd_elf_single_rel_hdr (input_section->output_section);
+      rel_hdr->sh_size -= rel_hdr->sh_entsize * deleted;
+      if (rel_hdr->sh_size == 0)
+	{
+	  /* It is too late to remove an empty reloc section.  Leave
+	     one NONE reloc.
+	     ??? What is wrong with an empty section???  */
+	  rel_hdr->sh_size = rel_hdr->sh_entsize;
+	  deleted -= 1;
+	}
+      rel_hdr = _bfd_elf_single_rel_hdr (input_section);
+      rel_hdr->sh_size -= rel_hdr->sh_entsize * deleted;
+      input_section->reloc_count -= deleted;
     }
 
   /* If we're emitting relocations, then shortly after this function