ld: Extract _bfd_elf_link_iterate_on_relocs

DT_RELR encodes consecutive R_*_RELATIVE relocations in GOT (the global
offset table) and data sections in a compact format:

https://groups.google.com/g/generic-abi/c/bX460iggiKg

On some targets, R_*_RELATIVE relocations are counted and the GOT offsets
are allocated when setting the dynamic section sizes after seeing all
relocations.  R_*_RELATIVE relocations are generated while relocating
sections after section layout has been finalized.

To prepare for DT_RELR implementation on these targets, extract
_bfd_elf_link_iterate_on_relocs from _bfd_elf_link_check_relocs so
that a backend can scan relocations in elf_backend_always_size_sections

For x86 targets, the old check_relocs is renamed to scan_relocs and a
new check_relocs is added to chek input sections and create dynamic
relocation sections so that they will be mapped to output sections.
scan_relocs is now called from elf_backend_always_size_sections.

Since relocations are scanned after __start, __stop, .startof. and
.sizeof. symbols have been finalized on x86, __[start|stop]_SECNAME for
--gc-sections -z start-stop-gc are now zero when all SECNAME sections
been garbage collected.  This is no need for elf_x86_start_stop_gc_p.

bfd/

	* elf-bfd.h (_bfd_elf_link_iterate_on_relocs): New.
	* elf32-i386.c (elf_i386_convert_load_reloc): Don't call
	elf_x86_start_stop_gc_p.
	(elf_i386_check_relocs): Renamed to ...
	(elf_i386_scan_relocs): This.  Don't call
	_bfd_elf_make_dynamic_reloc_section.
	(elf_i386_always_size_sections): New.
	(elf_backend_check_relocs): Removed.
	(elf_backend_always_size_sections): New.
	* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Don't call
	elf_x86_start_stop_gc_p.
	(elf_x86_64_check_relocs): Renamed to ...
	(elf_x86_64_scan_relocs): This.  Don't call
	_bfd_elf_make_dynamic_reloc_section.
	(elf_x86_64_always_size_sections): New.
	(elf_backend_check_relocs): Removed.
	(elf_backend_always_size_sections): New.
	* elflink.c (elf_link_check_or_scan_relocs):
	New.  Extracted from _bfd_elf_link_check_relocs.
	(_bfd_elf_link_check_relocs): Call elf_link_check_or_scan_relocs.
	* elfxx-x86.c (_bfd_x86_elf_check_relocs): New.
	* elfxx-x86.h (X86_64_NEED_DYNAMIC_RELOC_TYPE_P): New.
	(I386_NEED_DYNAMIC_RELOC_TYPE_P): Likewise.
	(X86_NEED_DYNAMIC_RELOC_TYPE_P): Likewise.
	(_bfd_x86_elf_check_relocs): Likewise.
	(elf_backend_check_relocs): Likewise.
	(elf_backend_always_size_sections): Removed.
	(elf_x86_start_stop_gc_p): Likewise.

ld/

	* testsuite/ld-i386/pr27491-1a.d: Updated.
	* testsuite/ld-x86-64/pr27491-1a.d: Likewise.

2 files changed, 4 insertions, 4 deletions

diff --git a/ld/testsuite/ld-i386/pr27491-1a.d b/ld/testsuite/ld-i386/pr27491-1a.d
index 006c176..39b25f6 100644
--- a/ld/testsuite/ld-i386/pr27491-1a.d
+++ b/ld/testsuite/ld-i386/pr27491-1a.d
@@ -9,6 +9,6 @@
 Disassembly of section .text:
 
 [a-f0-9]+ <foo>:
- +[a-f0-9]+:	8b 83 ([0-9a-f]{2} ){4}[ \t]+mov +-0x[a-f0-9]+\(%ebx\),%eax
- +[a-f0-9]+:	8b 83 ([0-9a-f]{2} ){4}[ \t]+mov +-0x[a-f0-9]+\(%ebx\),%eax
+ +[a-f0-9]+:	c7 c0 00 00 00 00    	mov    \$0x0,%eax
+ +[a-f0-9]+:	c7 c0 00 00 00 00    	mov    \$0x0,%eax
 #pass
diff --git a/ld/testsuite/ld-x86-64/pr27491-1a.d b/ld/testsuite/ld-x86-64/pr27491-1a.d
index ade5c6f..215124c 100644
--- a/ld/testsuite/ld-x86-64/pr27491-1a.d
+++ b/ld/testsuite/ld-x86-64/pr27491-1a.d
@@ -9,6 +9,6 @@
 Disassembly of section .text:
 
 [a-f0-9]+ <foo>:
- +[a-f0-9]+:	48 8b 05 ([0-9a-f]{2} ){4}[ \t]+mov +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
- +[a-f0-9]+:	48 8b 05 ([0-9a-f]{2} ){4}[ \t]+mov +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
+ +[a-f0-9]+:	48 c7 c0 00 00 00 00 	mov    \$0x0,%rax
+ +[a-f0-9]+:	48 c7 c0 00 00 00 00 	mov    \$0x0,%rax
 #pass