[binutils-gdb] Always count the NULL entry in dynamic symbol table

[H.J.Lu <hjl at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d5486c43728b4fa17c111a301c30a1e072eaec6a

commit d5486c43728b4fa17c111a301c30a1e072eaec6a
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Apr 26 03:53:07 2016 -0700

    Always count the NULL entry in dynamic symbol table
    
    There is an unused NULL entry at the head of dynamic symbol table which
    we must account for in our count even if the table is empty or unused
    since it is intended for the mandatory DT_SYMTAB tag (.dynsym section)
    in .dynamic section.
    
    	* elf-bfd.h (elf_link_hash_table): Update comments for
    	dynsymcount.
    	* elflink.c (_bfd_elf_link_renumber_dynsyms): Always count for
    	the unused NULL entry at the head of dynamic symbol table.
    	(bfd_elf_size_dynsym_hash_dynstr): Remove dynsymcount != 0
    	checks.

Diff:
---
 bfd/ChangeLog |  9 +++++++++
 bfd/elf-bfd.h |  4 ++--
 bfd/elflink.c | 30 +++++++++++++-----------------
 3 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index a8a29bd..746adad 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2016-04-26  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* elf-bfd.h (elf_link_hash_table): Update comments for
+	dynsymcount.
+	* elflink.c (_bfd_elf_link_renumber_dynsyms): Always count for
+	the unused NULL entry at the head of dynamic symbol table.
+	(bfd_elf_size_dynsym_hash_dynstr): Remove dynsymcount != 0
+	checks.
+
 2016-04-21  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* elflink.c (_bfd_elf_link_create_dynstrtab): Exclude linker
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 5dce70e..7447629 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -520,8 +520,8 @@ struct elf_link_hash_table
   union gotplt_union init_got_offset;
   union gotplt_union init_plt_offset;
 
-  /* The number of symbols found in the link which must be put into
-     the .dynsym section.  */
+  /* The number of symbols found in the link which is intended for the
+     mandatory DT_SYMTAB tag (.dynsym section) in .dynamic section.  */
   bfd_size_type dynsymcount;
 
   /* The string table of dynamic symbols, which becomes the .dynstr
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 6f67266..a6b3c94 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -905,11 +905,11 @@ _bfd_elf_link_renumber_dynsyms (bfd *output_bfd,
 			  elf_link_renumber_hash_table_dynsyms,
 			  &dynsymcount);
 
-  /* There is an unused NULL entry at the head of the table which
-     we must account for in our count.  We always create the dynsym
-     section, even if it is empty, with dynamic sections.  */
-  if (elf_hash_table (info)->dynamic_sections_created)
-    ++dynsymcount;
+  /* There is an unused NULL entry at the head of the table which we
+     must account for in our count even if the table is empty since it
+     is intended for the mandatory DT_SYMTAB tag (.dynsym section) in
+     .dynamic section.  */
+  dynsymcount++;
 
   elf_hash_table (info)->dynsymcount = dynsymcount;
   return dynsymcount;
@@ -6606,8 +6606,7 @@ bfd_elf_size_dynsym_hash_dynstr (bfd *output_bfd, struct bfd_link_info *info)
       /* Work out the size of the symbol version section.  */
       s = bfd_get_linker_section (dynobj, ".gnu.version");
       BFD_ASSERT (s != NULL);
-      if (dynsymcount != 0
-	  && (s->flags & SEC_EXCLUDE) == 0)
+      if ((s->flags & SEC_EXCLUDE) == 0)
 	{
 	  s->size = dynsymcount * sizeof (Elf_External_Versym);
 	  s->contents = (unsigned char *) bfd_zalloc (output_bfd, s->size);
@@ -6628,17 +6627,14 @@ bfd_elf_size_dynsym_hash_dynstr (bfd *output_bfd, struct bfd_link_info *info)
       BFD_ASSERT (s != NULL);
       s->size = dynsymcount * bed->s->sizeof_sym;
 
-      if (dynsymcount != 0)
-	{
-	  s->contents = (unsigned char *) bfd_alloc (output_bfd, s->size);
-	  if (s->contents == NULL)
-	    return FALSE;
+      s->contents = (unsigned char *) bfd_alloc (output_bfd, s->size);
+      if (s->contents == NULL)
+	return FALSE;
 
-	  /* The first entry in .dynsym is a dummy symbol.
-	     Clear all the section syms, in case we don't output them all.  */
-	  ++section_sym_count;
-	  memset (s->contents, 0, section_sym_count * bed->s->sizeof_sym);
-	}
+      /* The first entry in .dynsym is a dummy symbol.  Clear all the
+	 section syms, in case we don't output them all.  */
+      ++section_sym_count;
+      memset (s->contents, 0, section_sym_count * bed->s->sizeof_sym);
 
       elf_hash_table (info)->bucketcount = 0;