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.

1 files changed, 25 insertions, 35 deletions

diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h
index 16565a5..1bb8028 100644
--- a/bfd/elfxx-x86.h
+++ b/bfd/elfxx-x86.h
@@ -47,6 +47,25 @@
 #define X86_SIZE_TYPE_P(IS_X86_64, TYPE) \
   ((IS_X86_64) ? X86_64_SIZE_TYPE_P(TYPE) : I386_SIZE_TYPE_P (TYPE))
 
+#define X86_64_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \
+  (X86_64_SIZE_TYPE_P (TYPE) \
+   || X86_64_PCREL_TYPE_P (TYPE) \
+   || (TYPE) == R_X86_64_8 \
+   || (TYPE) == R_X86_64_16 \
+   || (TYPE) == R_X86_64_32 \
+   || (TYPE) == R_X86_64_32S \
+   || (TYPE) == R_X86_64_64)
+#define I386_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \
+  (I386_SIZE_TYPE_P (TYPE) \
+   || I386_PCREL_TYPE_P (TYPE) \
+   || (TYPE) == R_386_32 \
+   || (TYPE) == R_386_TLS_LE \
+   || (TYPE) == R_386_TLS_LE_32)
+#define X86_NEED_DYNAMIC_RELOC_TYPE_P(IS_X86_64, TYPE) \
+  ((IS_X86_64) \
+   ? X86_64_NEED_DYNAMIC_RELOC_TYPE_P (TYPE) \
+   : I386_NEED_DYNAMIC_RELOC_TYPE_P (TYPE))
+
 #define PLT_CIE_LENGTH		20
 #define PLT_FDE_LENGTH		36
 #define PLT_FDE_START_OFFSET	4 + PLT_CIE_LENGTH + 8
@@ -653,6 +672,10 @@ extern int _bfd_x86_elf_compare_relocs
 extern bool _bfd_x86_elf_link_check_relocs
   (bfd *, struct bfd_link_info *);
 
+extern bool _bfd_x86_elf_check_relocs
+  (bfd *, struct bfd_link_info *, asection *,
+   const Elf_Internal_Rela *);
+
 extern bool _bfd_elf_x86_valid_reloc_p
   (asection *, struct bfd_link_info *, struct elf_x86_link_hash_table *,
    const Elf_Internal_Rela *, struct elf_link_hash_entry *,
@@ -730,10 +753,10 @@ extern void _bfd_x86_elf_link_report_relative_reloc
 #define bfd_elf32_bfd_link_check_relocs \
   _bfd_x86_elf_link_check_relocs
 
+#define elf_backend_check_relocs \
+  _bfd_x86_elf_check_relocs
 #define elf_backend_size_dynamic_sections \
   _bfd_x86_elf_size_dynamic_sections
-#define elf_backend_always_size_sections \
-  _bfd_x86_elf_always_size_sections
 #define elf_backend_merge_symbol_attribute \
   _bfd_x86_elf_merge_symbol_attribute
 #define elf_backend_copy_indirect_symbol \
@@ -757,39 +780,6 @@ extern void _bfd_x86_elf_link_report_relative_reloc
 
 #define ELF_P_ALIGN ELF_MINPAGESIZE
 
-/* Return true if H is a __start_SECNAME/__stop_SECNAME symbol for the
-   SECNAME section which has been garbage collected by --gc-sections
-   -z start-stop-gc.  */
-
-static inline bool
-elf_x86_start_stop_gc_p (struct bfd_link_info *link_info,
-			 struct elf_link_hash_entry *h)
-{
-  if (h->start_stop
-      && link_info->gc_sections
-      && link_info->start_stop_gc)
-    {
-      asection *s = h->root.u.def.section;
-
-      do
-	{
-	  /* Return false if any SECNAME section is kept.  */
-	  if (s->gc_mark)
-	    return false;
-	  s = bfd_get_next_section_by_name (s->owner, s);
-	}
-      while (s != NULL);
-
-      /* Return true only if all SECNAME sections have been garbage
-	 collected.  */
-      return true;
-    }
-
-  /* Return false if H isn't a __start_SECNAME/__stop_SECNAME symbol or
-     --gc-sections or -z start-stop-gc isn't used.  */
-  return false;
-}
-
 /* Allocate x86 GOT info for local symbols.  */
 
 static inline bool