[Patch mach-o/gas] set section vma.

[Iain Sandoe <developer at sandoe-acoustics dot co dot uk>]

It would be good to sort this out soon - because otherwise we're going  
to end up with a *lot* of tests to change.

There's a constraint that zerofill sections must appear after all  
others in their segment.
Likewise GB zerofill must appear last.

===

If there were no external model, I would have chosen to sort the  
sections as per ld's requirements - however, that's not what the  
native 'as' does, and the implementation follows the latter.

(there are a bunch of tests to adjust when this is applied - but  
nothing exciting to review - just filling in numbers where there is  
currently 000000)

OK?
Iain

gas:

	* config/obj-macho.c (obj_mach_o_set_vma_data): New type.
	(obj_mach_o_set_section_vma): New.
	(obj_mach_o_post_relax_hook): New.
	* config/obj-macho.h (md_post_relax_hook): Define.
	(obj_mach_o_post_relax_hook): Declare.

 gas/config/obj-macho.c |   66 +++++++++++++++++++++++++++++++++++++++ 
+++++++++
 gas/config/obj-macho.h |    3 ++
 2 files changed, 69 insertions(+), 0 deletions(-)

diff --git a/gas/config/obj-macho.c b/gas/config/obj-macho.c
index 61e6771..46fb9b4 100644
--- a/gas/config/obj-macho.c
+++ b/gas/config/obj-macho.c
@@ -1471,6 +1471,72 @@ obj_macho_frob_symbol (struct symbol *sp)
   return 0;
 }

+/* This is a case where, if starting from scratch, I'd do things  
differently.
+
+   IMO the object file would be tidier if sorted into the same order  
that ld
+   requires.  However, the native tool doesn't do that - it leaves  
the sections
+   in the order they appear in the source, and fudges the section vma  
so that
+   the constraints of zerofill sections are met.
+
+   We follow this for now - if nothing else, it makes comparison  
easier, but
+   one day we might wish to re-order.  */
+
+typedef struct obj_mach_o_set_vma_data
+{
+  bfd_vma vma;
+  unsigned zerofill;
+} obj_mach_o_set_vma_data;
+
+/* We do three passes through to set the vma, so that:
+   zerofill sections appear after all others in their segment
+   GB zerofill appear last.  */
+
+static void
+obj_mach_o_set_section_vma (bfd *abfd ATTRIBUTE_UNUSED, asection  
*sec, void *xxx)
+{
+  bfd_mach_o_section *ms = bfd_mach_o_get_mach_o_section (sec);
+  unsigned bfd_align = bfd_get_section_alignment (abfd, sec);
+  obj_mach_o_set_vma_data *p = (struct obj_mach_o_set_vma_data *)xxx;
+  unsigned flags = (ms->flags & BFD_MACH_O_SECTION_TYPE_MASK);
+  unsigned zf;
+
+  zf = 0;
+  if (flags == BFD_MACH_O_S_ZEROFILL)
+    zf = 1;
+  else if (flags == BFD_MACH_O_S_GB_ZEROFILL)
+    zf = 2;
+
+  if (p->zerofill != zf)
+    return;
+
+  /* We know the section size now - so make a vma for the section just
+     based on order.  */
+  ms->size = bfd_get_section_size (sec);
+
+  /* Make sure that the align agrees, and set to the largest value  
chosen.  */
+  ms->align = ms->align > bfd_align ? ms->align : bfd_align;
+  bfd_set_section_alignment (abfd, sec, ms->align);
+
+  p->vma += (1 << ms->align) - 1;
+  p->vma &= ~((1 << ms->align) - 1);
+  ms->addr = p->vma;
+  bfd_set_section_vma (abfd, sec, p->vma);
+  p->vma += ms->size;
+}
+
+void obj_mach_o_post_relax_hook (void)
+{
+  obj_mach_o_set_vma_data d;
+  d.vma = 0;
+  d.zerofill = 0;
+
+  bfd_map_over_sections (stdoutput, obj_mach_o_set_section_vma, (char  
*) &d);
+  d.zerofill = 1;
+  bfd_map_over_sections (stdoutput, obj_mach_o_set_section_vma, (char  
*) &d);
+  d.zerofill = 2;
+  bfd_map_over_sections (stdoutput, obj_mach_o_set_section_vma, (char  
*) &d);
+}
+
 static void
 obj_mach_o_set_indirect_symbols (bfd *abfd, asection *sec,
 				 void *xxx ATTRIBUTE_UNUSED)
diff --git a/gas/config/obj-macho.h b/gas/config/obj-macho.h
index 9f1f3db..2fc5cb6 100644
--- a/gas/config/obj-macho.h
+++ b/gas/config/obj-macho.h
@@ -62,6 +62,9 @@ extern void obj_macho_frob_label (struct symbol *);
 #define obj_frob_symbol(s, punt) punt = obj_macho_frob_symbol(s)
 extern int obj_macho_frob_symbol (struct symbol *);

+#define md_post_relax_hook obj_mach_o_post_relax_hook()
+void obj_mach_o_post_relax_hook (void);
+
 #define obj_frob_file_after_relocs obj_mach_o_frob_file_after_relocs
 extern void obj_mach_o_frob_file_after_relocs (void);