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, 33 insertions, 0 deletions

diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index daae52b9537..500f8bfa309 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -2784,6 +2784,11 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		      outrel.r_addend = (h->root.u.def.value
 					 + h->root.u.def.section->output_section->vma
 					 + h->root.u.def.section->output_offset);
+
+		      if (htab->params->report_relative_reloc)
+			_bfd_x86_elf_link_report_relative_reloc
+			  (info, input_section, h, sym,
+			   "R_X86_64_IRELATIVE", &outrel);
 		    }
 		  else
 		    {
@@ -2940,6 +2945,12 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 				 + off);
 	      outrel.r_info = htab->r_info (0, R_X86_64_RELATIVE);
 	      outrel.r_addend = relocation;
+
+	      if (htab->params->report_relative_reloc)
+		_bfd_x86_elf_link_report_relative_reloc
+		  (info, input_section, h, sym, "R_X86_64_RELATIVE",
+		   &outrel);
+
 	      elf_append_rela (output_bfd, s, &outrel);
 	    }
 
@@ -3221,6 +3232,7 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 	      Elf_Internal_Rela outrel;
 	      bfd_boolean skip, relocate;
 	      asection *sreloc;
+	      const char *relative_reloc_name = NULL;
 
 	      /* When generating a shared object, these relocations
 		 are copied into the output file to be resolved at run
@@ -3259,6 +3271,7 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		      relocate = TRUE;
 		      outrel.r_info = htab->r_info (0, R_X86_64_RELATIVE);
 		      outrel.r_addend = relocation + rel->r_addend;
+		      relative_reloc_name = "R_X86_64_RELATIVE";
 		    }
 		  else if (r_type == R_X86_64_64
 			   && !ABI_64_P (output_bfd))
@@ -3267,6 +3280,7 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		      outrel.r_info = htab->r_info (0,
 						    R_X86_64_RELATIVE64);
 		      outrel.r_addend = relocation + rel->r_addend;
+		      relative_reloc_name = "R_X86_64_RELATIVE64";
 		      /* Check addend overflow.  */
 		      if ((outrel.r_addend & 0x80000000)
 			  != (rel->r_addend & 0x80000000))
@@ -3333,6 +3347,12 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		  goto check_relocation_error;
 		}
 
+	      if (relative_reloc_name
+		  && htab->params->report_relative_reloc)
+		_bfd_x86_elf_link_report_relative_reloc
+		  (info, input_section, h, sym, relative_reloc_name,
+		   &outrel);
+
 	      elf_append_rela (output_bfd, sreloc, &outrel);
 
 	      /* If this reloc is against an external symbol, we do
@@ -4292,6 +4312,11 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
 	      rela.r_addend = (h->root.u.def.value
 			       + h->root.u.def.section->output_section->vma
 			       + h->root.u.def.section->output_offset);
+
+	      if (htab->params->report_relative_reloc)
+		_bfd_x86_elf_link_report_relative_reloc
+		  (info, relplt, h, sym, "R_X86_64_IRELATIVE", &rela);
+
 	      /* R_X86_64_IRELATIVE comes last.  */
 	      plt_index = htab->next_irelative_index--;
 	    }
@@ -4409,6 +4434,7 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
     {
       Elf_Internal_Rela rela;
       asection *relgot = htab->elf.srelgot;
+      const char *relative_reloc_name = NULL;
 
       /* This symbol has an entry in the global offset table.  Set it
 	 up.  */
@@ -4447,6 +4473,7 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
 		  rela.r_addend = (h->root.u.def.value
 				   + h->root.u.def.section->output_section->vma
 				   + h->root.u.def.section->output_offset);
+		  relative_reloc_name = "R_X86_64_IRELATIVE";
 		}
 	      else
 		goto do_glob_dat;
@@ -4494,6 +4521,7 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
 	  rela.r_addend = (h->root.u.def.value
 			   + h->root.u.def.section->output_section->vma
 			   + h->root.u.def.section->output_offset);
+	  relative_reloc_name = "R_X86_64_RELATIVE";
 	}
       else
 	{
@@ -4505,6 +4533,11 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
 	  rela.r_addend = 0;
 	}
 
+      if (relative_reloc_name != NULL
+	  && htab->params->report_relative_reloc)
+	_bfd_x86_elf_link_report_relative_reloc
+	  (info, relgot, h, sym, relative_reloc_name, &rela);
+
       elf_append_rela (output_bfd, relgot, &rela);
     }