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, 47 insertions, 0 deletions

diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index 3a0dffc..8cda8d2 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -1742,6 +1742,53 @@ _bfd_x86_elf_link_fixup_ifunc_symbol (struct bfd_link_info *info,
     }
 }
 
+/* Report relative relocation.  */
+
+void
+_bfd_x86_elf_link_report_relative_reloc
+  (struct bfd_link_info *info, asection *asect,
+   struct elf_link_hash_entry *h, Elf_Internal_Sym *sym,
+   const char *reloc_name, const void *reloc)
+{
+  const char *name;
+  bfd *abfd;
+  const Elf_Internal_Rela *rel = (const Elf_Internal_Rela *) reloc;
+  char r_offset[30], r_info[30];
+
+  /* Use the output BFD for linker created sections.  */
+  if ((asect->flags & SEC_LINKER_CREATED) != 0)
+    abfd = info->output_bfd;
+  else
+    abfd = asect->owner;
+
+  if (h != NULL && h->root.root.string != NULL)
+    name = h->root.root.string;
+  else
+    name = bfd_elf_sym_name (abfd, &elf_symtab_hdr (abfd), sym, NULL);
+
+  bfd_sprintf_vma (abfd, r_offset, rel->r_offset);
+  bfd_sprintf_vma (abfd, r_info, rel->r_info);
+
+  if (asect->use_rela_p)
+    {
+      char r_addend[30];
+
+      bfd_sprintf_vma (abfd, r_addend, rel->r_addend);
+
+      info->callbacks->einfo
+	(_("%pB: %s (offset: 0x%s, info: 0x%s, addend: 0x%s) against "
+	   "'%s' " "for section '%pA' in %pB\n"),
+	 info->output_bfd, reloc_name, r_offset, r_info, r_addend,
+	 name, asect, abfd);
+    }
+  else
+    info->callbacks->einfo
+      (_("%pB: %s (offset: 0x%s, info: 0x%s) against '%s' for section "
+	 "'%pA' in %pB\n"),
+       info->output_bfd, reloc_name, r_offset, r_info, name,
+       asect, abfd);
+}
+
 /* Return TRUE if symbol should be hashed in the `.gnu.hash' section.  */
 
 bfd_boolean