[PATCH] elf: Cache ".interp" section pointer in elf_link_hash_table

[H.J. Lu]

If there is no interpreter (no ".interp" sectio), weak undefined symbols
will always be zero at run-time.  Cache ".interp" section pointer in
elf_link_hash_table so that a backend can use it to check if weak
undefined symbols should be resolved to zero at link-time.

	PR ld/33427
	* elf-bfd.h (elf_link_hash_table): Add interp.
	* elflink.c (_bfd_elf_link_create_dynamic_sections): Cache the
	pointer to ".interp" section in interp.
	* elfxx-x86.c (_bfd_x86_elf_link_symbol_references_local): Check
	htab->elf.interp instead of htab->interp.
	(_bfd_x86_elf_link_setup_gnu_properties): Use htab->elf.interp.
	* elfxx-x86.h (elf_x86_link_hash_table): Remove interp.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---
 bfd/elf-bfd.h   | 1 +
 bfd/elflink.c   | 1 +
 bfd/elfxx-x86.c | 7 ++-----
 bfd/elfxx-x86.h | 1 -
 4 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index de7cc410a99..51e6ae7bb78 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -774,6 +774,7 @@ struct elf_link_hash_table
   asection *dynsym;
   asection *srelrdyn;
   asection *dynamic;
+  asection *interp;
 };
 
 /* Returns TRUE if the hash table is a struct elf_link_hash_table.  */
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 53ec792852c..b8ffcab419c 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -354,6 +354,7 @@ _bfd_elf_link_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info)
 					      flags | SEC_READONLY);
       if (s == NULL)
 	return false;
+      elf_hash_table (info)->interp = s;
     }
 
   /* Create sections to hold version informations.  These are removed
diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index 06265ee4e15..4ca4c3a3948 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -3665,7 +3665,7 @@ _bfd_x86_elf_link_symbol_references_local (struct bfd_link_info *info,
       || (h->root.type == bfd_link_hash_undefweak
 	  && (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
 	      || (bfd_link_executable (info)
-		  && htab->interp == NULL)
+		  && htab->elf.interp == NULL)
 	      || info->dynamic_undefined_weak == 0))
       || ((h->def_regular || ELF_COMMON_DEF_P (h))
 	  && info->version_info != NULL
@@ -4704,13 +4704,10 @@ _bfd_x86_elf_link_setup_gnu_properties
 	 section to the interpreter.  */
       if (bfd_link_executable (info) && !info->nointerp)
 	{
-	  asection *s = bfd_get_linker_section (dynobj, ".interp");
-	  if (s == NULL)
-	    abort ();
+	  asection *s = htab->elf.interp;
 	  s->size = htab->dynamic_interpreter_size;
 	  s->contents = (unsigned char *) htab->dynamic_interpreter;
 	  s->alloced = 1;
-	  htab->interp = s;
 	}
 
       if (normal_target)
diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h
index 5593203f9ec..1ebc9d2f2e5 100644
--- a/bfd/elfxx-x86.h
+++ b/bfd/elfxx-x86.h
@@ -602,7 +602,6 @@ struct elf_x86_link_hash_table
   struct elf_link_hash_table elf;
 
   /* Short-cuts to get to dynamic linker sections.  */
-  asection *interp;
   asection *plt_eh_frame;
   asection *plt_second;
   asection *plt_second_eh_frame;
-- 
2.51.0