ld/x86: Add -z report-relative-reloc

Linker generated relative relocations don't have symbol info:

[hjl@gnu-cfl-2 tmpdir]$ readelf -rW dump

Relocation section '.rela.dyn' at offset 0x180 contains 2 entries:
 Offset     Info    Type                Sym. Value  Symbol's Name + Addend
00002f70  00000008 R_X86_64_RELATIVE                 1000
00002f68  00000025 R_X86_64_IRELATIVE                1007
[hjl@gnu-cfl-2 tmpdir]$

Add -z report-relative-reloc to x86 ELF linker to report dynamic relative
relocations:

[hjl@gnu-cfl-2 tmpdir]$ ../ld-new -pie -melf32_x86_64 -z report-relative-reloc -o dump report-reloc-1.o
dump: R_X86_64_IRELATIVE (offset: 0x00002f68, info: 0x00000025, addend: 0x00001007) against 'ifunc' for section '.data.rel.ro.local' in report-reloc-1.o
dump: R_X86_64_RELATIVE (offset: 0x00002f70, info: 0x00000008, addend: 0x00001000) against '_start' for section '.data.rel.ro.local' in report-reloc-1.o
[hjl@gnu-cfl-2 tmpdir]$

It can be used to map relative relocations to corresponding symbols.

bfd/

	* elf-linker-x86.h (elf_linker_x86_params): Add
	report_relative_reloc.
	* elf32-i386.c (elf_i386_relocate_section): Call
	_bfd_x86_elf_link_report_relative_reloc to report relative
	relocations for -z report-relative-reloc.
	(elf_i386_finish_dynamic_symbol): Likewse.
	* elf64-x86-64.c (elf_x86_64_relocate_section): Likewse.
	(elf_x86_64_finish_dynamic_symbol): Likewse.
	* elfxx-x86.c (_bfd_x86_elf_link_report_relative_reloc): New
	function.
	* elfxx-x86.h (_bfd_x86_elf_link_report_relative_reloc): New
	prototype.

ld/

	* NEWS: Mention -z report-relative-reloc.
	* ld.texi: Document -z report-relative-reloc.
	* emulparams/elf32_x86_64.sh: Source x86-report-relative.sh.
	* emulparams/elf_i386.sh: Likewse.
	* emulparams/elf_x86_64.sh: Likewse.
	* emulparams/x86-report-relative.sh: New file.
	* testsuite/ld-i386/report-reloc-1.d: Likewse.
	* testsuite/ld-i386/report-reloc-1.l: Likewse.
	* testsuite/ld-i386/report-reloc-1.s: Likewse.
	* testsuite/ld-x86-64/report-reloc-1-x32.d: Likewse.
	* testsuite/ld-x86-64/report-reloc-1.d: Likewse.
	* testsuite/ld-x86-64/report-reloc-1.l: Likewse.
	* testsuite/ld-x86-64/report-reloc-1.s: Likewse.
	* testsuite/ld-i386/i386.exp: Run report-reloc-1.
	* testsuite/ld-x86-64/x86-64.exp: Run report-reloc-1 and
	report-reloc-1-x32.

1 files changed, 36 insertions, 0 deletions

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index db7dd10d3d3..04ea7d088b6 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -2409,6 +2409,12 @@ elf_i386_relocate_section (bfd *output_bfd,
 
 		      /* This symbol is resolved locally.  */
 		      outrel.r_info = ELF32_R_INFO (0, R_386_IRELATIVE);
+
+		      if (htab->params->report_relative_reloc)
+			_bfd_x86_elf_link_report_relative_reloc
+			  (info, input_section, h, sym,
+			   "R_386_IRELATIVE", &outrel);
+
 		      bfd_put_32 (output_bfd,
 				  (h->root.u.def.value
 				   + h->root.u.def.section->output_section->vma
@@ -2532,6 +2538,12 @@ elf_i386_relocate_section (bfd *output_bfd,
 				 + htab->elf.sgot->output_offset
 				 + off);
 	      outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
+
+	      if (htab->params->report_relative_reloc)
+		_bfd_x86_elf_link_report_relative_reloc
+		  (info, input_section, h, sym, "R_386_RELATIVE",
+		   &outrel);
+
 	      elf_append_rel (output_bfd, s, &outrel);
 	    }
 
@@ -2738,6 +2750,11 @@ elf_i386_relocate_section (bfd *output_bfd,
 		  /* This symbol is local, or marked to become local.  */
 		  relocate = TRUE;
 		  outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
+
+		  if (htab->params->report_relative_reloc)
+		    _bfd_x86_elf_link_report_relative_reloc
+		      (info, input_section, h, sym, "R_386_RELATIVE",
+		       &outrel);
 		}
 
 	      sreloc = elf_section_data (input_section)->sreloc;
@@ -2769,6 +2786,12 @@ elf_i386_relocate_section (bfd *output_bfd,
 				+ input_section->output_section->vma
 				+ input_section->output_offset;
 	      outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
+
+	      if (htab->params->report_relative_reloc)
+		_bfd_x86_elf_link_report_relative_reloc
+		  (info, input_section, h, sym, "R_386_RELATIVE",
+		   &outrel);
+
 	      sreloc = elf_section_data (input_section)->sreloc;
 	      if (sreloc == NULL)
 		abort ();
@@ -3664,6 +3687,11 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
 			   + h->root.u.def.section->output_offset),
 			  gotplt->contents + got_offset);
 	      rel.r_info = ELF32_R_INFO (0, R_386_IRELATIVE);
+
+	      if (htab->params->report_relative_reloc)
+		_bfd_x86_elf_link_report_relative_reloc
+		  (info, relplt, h, sym, "R_386_IRELATIVE", &rel);
+
 	      /* R_386_IRELATIVE comes last.  */
 	      plt_index = htab->next_irelative_index--;
 	    }
@@ -3762,6 +3790,7 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
     {
       Elf_Internal_Rela rel;
       asection *relgot = htab->elf.srelgot;
+      const char *relative_reloc_name = NULL;
 
       /* This symbol has an entry in the global offset table.  Set it
 	 up.  */
@@ -3802,6 +3831,7 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
 			       + h->root.u.def.section->output_offset),
 			      htab->elf.sgot->contents + h->got.offset);
 		  rel.r_info = ELF32_R_INFO (0, R_386_IRELATIVE);
+		  relative_reloc_name = "R_386_IRELATIVE";
 		}
 	      else
 		goto do_glob_dat;
@@ -3844,6 +3874,7 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
 	{
 	  BFD_ASSERT((h->got.offset & 1) != 0);
 	  rel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
+	  relative_reloc_name = "R_386_RELATIVE";
 	}
       else
 	{
@@ -3854,6 +3885,11 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
 	  rel.r_info = ELF32_R_INFO (h->dynindx, R_386_GLOB_DAT);
 	}
 
+      if (relative_reloc_name != NULL
+	  && htab->params->report_relative_reloc)
+	_bfd_x86_elf_link_report_relative_reloc
+	  (info, relgot, h, sym, relative_reloc_name, &rel);
+
       elf_append_rel (output_bfd, relgot, &rel);
     }