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[PATCH] Create just one PT_NOTE for consecutive loadable .note* sections instead of one for each section
- From: Jakub Jelinek <jakub at redhat dot com>
- To: binutils at sources dot redhat dot com
- Cc: roland at redhat dot com
- Date: Thu, 28 Jun 2007 17:29:03 +0200
- Subject: [PATCH] Create just one PT_NOTE for consecutive loadable .note* sections instead of one for each section
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
Roland noted that we generate one PT_NOTE segment for each .note*
output section. That should be unnecessary if the sections
are consecutive. As Roland plans to add a new loadable .note*
section to basically every binary and library, we'd unnecessarily
have two PT_NOTE sections in most binaries (one for this new note,
one for .note.ABI-tag).
2007-06-28 Jakub Jelinek <jakub@redhat.com>
* elf.c (get_program_header_size): Adjacent loadable .note*
sections need just one PT_NOTE segment.
(_bfd_elf_map_sections_to_segments): Likewise.
--- bfd/elf.c.jj 2007-06-28 12:52:44.000000000 +0200
+++ bfd/elf.c 2007-06-28 16:53:52.000000000 +0200
@@ -3681,6 +3681,14 @@ get_program_header_size (bfd *abfd, stru
{
/* We need a PT_NOTE segment. */
++segs;
+ /* Try to create just one PT_NOTE segment
+ for all adjacent loadable .note* sections. */
+ if (s->alignment_power == 2)
+ while (s->next != NULL
+ && s->next->alignment_power == 2
+ && (s->next->flags & SEC_LOAD) != 0
+ && CONST_STRNEQ (s->next->name, ".note"))
+ s = s->next;
}
}
@@ -4055,25 +4063,43 @@ _bfd_elf_map_sections_to_segments (bfd *
pm = &m->next;
}
- /* For each loadable .note section, add a PT_NOTE segment. We don't
- use bfd_get_section_by_name, because if we link together
- nonloadable .note sections and loadable .note sections, we will
- generate two .note sections in the output file. FIXME: Using
- names for section types is bogus anyhow. */
+ /* For each batch of consecutive loadable .note sections,
+ add a PT_NOTE segment. We don't use bfd_get_section_by_name,
+ because if we link together nonloadable .note sections and
+ loadable .note sections, we will generate two .note sections
+ in the output file. FIXME: Using names for section types is
+ bogus anyhow. */
for (s = abfd->sections; s != NULL; s = s->next)
{
if ((s->flags & SEC_LOAD) != 0
&& CONST_STRNEQ (s->name, ".note"))
{
+ asection *s2;
+ unsigned count = 1;
amt = sizeof (struct elf_segment_map);
+ if (s->alignment_power == 2)
+ for (s2 = s; s2->next != NULL; s2 = s2->next)
+ if (s2->next->alignment_power == 2
+ && (s2->next->flags & SEC_LOAD) != 0
+ && CONST_STRNEQ (s2->next->name, ".note")
+ && align_power (s2->vma + s2->size, 2) == s2->next->vma)
+ count++;
+ else
+ break;
+ amt += (count - 1) * sizeof (asection *);
m = bfd_zalloc (abfd, amt);
if (m == NULL)
goto error_return;
m->next = NULL;
m->p_type = PT_NOTE;
- m->count = 1;
- m->sections[0] = s;
-
+ m->count = count;
+ while (count > 1)
+ {
+ m->sections[m->count - count--] = s;
+ BFD_ASSERT ((s->flags & SEC_THREAD_LOCAL) == 0);
+ s = s->next;
+ }
+ m->sections[m->count - 1] = s;
*pm = m;
pm = &m->next;
}
Jakub