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Re: output section ALIGN and relocatable links
On Wed, Nov 16, 2005 at 05:00:40PM +1030, Alan Modra wrote:
> On Tue, Nov 15, 2005 at 10:36:39AM -0800, Sterling Augustine wrote:
> > The output section's alignment is only copied to the output bfd's
> > alignment in lang_add_section, which is only called when an input
> > section goes into the output section.
>
> I'll look into it. The right place to set the alignment is in init_os.
> Hmm, I also think HJ's patch should have made this sort of ALIGN
> set the minimum output section alignment, not override input sections.
* ld.texinfo (Forced Output Alignment): Specify that this is an
alignment increase, not an override.
* ldlang.c (init_os): Set output section alignment here..
(lang_add_section): ..rather than here.
(lang_size_sections_1): Consolidate alignment code. Warn if section
alignment affects start address when explicit address given.
Index: ld/ld.texinfo
===================================================================
RCS file: /cvs/src/src/ld/ld.texinfo,v
retrieving revision 1.151
diff -u -p -r1.151 ld.texinfo
--- ld/ld.texinfo 24 Oct 2005 23:07:12 -0000 1.151
+++ ld/ld.texinfo 16 Nov 2005 07:03:54 -0000
@@ -3775,9 +3775,7 @@ for (dst = &_bstart; dst< &_bend; dst++)
@kindex ALIGN(@var{section_align})
@cindex forcing output section alignment
@cindex output section alignment
-You can force an output section alignment by using ALIGN. The value
-specified overrides any alignment given by input sections, whether
-larger or smaller.
+You can increase an output section's alignment by using ALIGN.
@node Forced Input Alignment
@subsubsection Forced Input Alignment
Index: ld/ldlang.c
===================================================================
RCS file: /cvs/src/src/ld/ldlang.c,v
retrieving revision 1.204
diff -u -p -r1.204 ldlang.c
--- ld/ldlang.c 4 Nov 2005 13:26:53 -0000 1.204
+++ ld/ldlang.c 16 Nov 2005 07:03:57 -0000
@@ -1720,6 +1720,10 @@ init_os (lang_output_section_statement_t
if (s->load_base != NULL)
exp_init_os (s->load_base);
+ /* If supplied an alignment, set it. */
+ if (s->section_alignment != -1)
+ s->bfd_section->alignment_power = s->section_alignment;
+
if (isec)
bfd_init_private_section_data (isec->owner, isec,
output_bfd, s->bfd_section,
@@ -1941,10 +1945,6 @@ lang_add_section (lang_statement_list_ty
if (section->alignment_power > output->bfd_section->alignment_power)
output->bfd_section->alignment_power = section->alignment_power;
- /* If supplied an alignment, then force it. */
- if (output->section_alignment != -1)
- output->bfd_section->alignment_power = output->section_alignment;
-
if (bfd_get_arch (section->owner) == bfd_arch_tic54x
&& (section->flags & SEC_TIC54X_BLOCK) != 0)
{
@@ -4144,6 +4144,8 @@ lang_size_sections_1
}
else
{
+ bfd_vma savedot;
+
if (os->addr_tree == NULL)
{
/* No address specified for this section, get one
@@ -4193,27 +4195,20 @@ lang_size_sections_1
}
newdot = os->region->current;
-
- if (os->section_alignment == -1)
- {
- bfd_vma savedot = newdot;
- newdot = align_power (newdot,
- os->bfd_section->alignment_power);
-
- if (newdot != savedot
- && config.warn_section_align
- && expld.phase != lang_mark_phase_enum)
- einfo (_("%P: warning: changing start of section"
- " %s by %lu bytes\n"),
- os->name, (unsigned long) (newdot - savedot));
- }
}
- /* The section starts here.
- First, align to what the section needs. */
-
- if (os->section_alignment != -1)
- newdot = align_power (newdot, os->section_alignment);
+ /* Align to what the section needs. */
+ savedot = newdot;
+ newdot = align_power (newdot,
+ os->bfd_section->alignment_power);
+
+ if (newdot != savedot
+ && (config.warn_section_align
+ || os->addr_tree != NULL)
+ && expld.phase != lang_mark_phase_enum)
+ einfo (_("%P: warning: changing start of section"
+ " %s by %lu bytes\n"),
+ os->name, (unsigned long) (newdot - savedot));
bfd_set_section_vma (0, os->bfd_section, newdot);
--
Alan Modra
IBM OzLabs - Linux Technology Centre