[Patch mach-o/gas] support .previous
Iain Sandoe
developer@sandoe-acoustics.co.uk
Sun Jan 1 16:11:00 GMT 2012
.previous is a nice feature and will help us with compatibility with
elf-style code.
OK?
Iain
gas:
* config/obj-macho.c (previous_section): New file-scope var.
(obj_mach_o_parse_section): Split from obj_mach_o_section.
(obj_mach_o_section): Use obj_mach_o_parse_section, update previous.
(obj_mach_o_known_section): Update previous.
(obj_mach_o_objc_section): Likewise.
(obj_mach_o_debug_section): Likewise.
(obj_mach_o_opt_tgt_section): Likewise.
(obj_mach_o_get_base_section): Split from obj_mach_o_base_section.
(obj_mach_o_base_section): Use obj_mach_o_get_base_section, update
previous.
(obj_mach_o_previous): New.
(mach_o_pseudo_table): Add previous.
gas/testsuite:
* gas/mach-o/previous-1.d: New.
* gas/mach-o/previous-1.s: New.
* gas/mach-o/warn-prev-1.s: New.
==
gas/config/obj-macho.c | 185 ++++++++++++++++++++++
+---------
gas/testsuite/gas/mach-o/previous-1.d | 8 ++
gas/testsuite/gas/mach-o/previous-1.s | 20 ++++
gas/testsuite/gas/mach-o/warn-prev-1.s | 5 +
4 files changed, 167 insertions(+), 51 deletions(-)
diff --git a/gas/config/obj-macho.c b/gas/config/obj-macho.c
index 74fb0c9..abea09b 100644
--- a/gas/config/obj-macho.c
+++ b/gas/config/obj-macho.c
@@ -1,5 +1,5 @@
/* Mach-O object file format
- Copyright 2009, 2011 Free Software Foundation, Inc.
+ Copyright 2009, 2011, 2012 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
@@ -48,6 +48,9 @@
/* Forward decl. */
static segT obj_mach_o_segT_from_bfd_name (const char *nam, int
must_succeed);
+/* Support for .previous for improved compatibility with elf-style
code. */
+static segT previous_section;
+
/* TODO: Implement "-dynamic"/"-static" command line options. */
static int obj_mach_o_is_static;
@@ -175,8 +178,8 @@ collect_16char_name (char *dest, const char *msg,
int require_comma)
Not all section types and attributes are accepted by the Darwin
system
assemblers as user-specifiable - although, at present, we do
here. */
-static void
-obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
+static segT
+obj_mach_o_parse_section (void)
{
char *p;
char c;
@@ -196,17 +199,13 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
char segname[17];
char sectname[17];
-#ifdef md_flush_pending_output
- md_flush_pending_output ();
-#endif
-
/* Zero-length segment and section names are allowed. */
/* Parse segment name. */
memset (segname, 0, sizeof(segname));
if (collect_16char_name (segname, "segment", 1))
{
ignore_rest_of_line ();
- return;
+ return NULL;
}
input_line_pointer++; /* Skip the terminating ',' */
@@ -240,7 +239,7 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
as_bad (_("unknown or invalid section type '%s'"), p);
p[len] = tmpc;
ignore_rest_of_line ();
- return;
+ return NULL;
}
else
sectype_given = 1;
@@ -278,7 +277,7 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
as_bad (_("unknown or invalid section attribute
'%s'"), p);
p[len] = tmpc;
ignore_rest_of_line ();
- return;
+ return NULL;
}
else
{
@@ -297,7 +296,7 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
{
as_bad (_("unexpected section size information"));
ignore_rest_of_line ();
- return;
+ return NULL;
}
input_line_pointer++;
@@ -307,7 +306,7 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
{
as_bad (_("missing sizeof_stub expression"));
ignore_rest_of_line ();
- return;
+ return NULL;
}
}
}
@@ -341,8 +340,8 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
name = n;
}
- /* Sub-segments don't exists as is on Mach-O. */
- sec = subseg_new (name, 0);
+ /* Get or create the section. */
+ sec = subseg_get (name, 0);
oldflags = bfd_get_section_flags (stdoutput, sec);
msect = bfd_mach_o_get_mach_o_section (sec);
@@ -375,7 +374,30 @@ obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
|| msect->flags != (secattr | sectype))
as_warn (_("Ignoring changed section attributes for %s"), name);
}
- demand_empty_rest_of_line ();
+
+ return sec;
+}
+
+static void
+obj_mach_o_section (int ignore ATTRIBUTE_UNUSED)
+{
+ segT new_seg;
+ segT old_seg = now_seg;
+
+#ifdef md_flush_pending_output
+ md_flush_pending_output ();
+#endif
+
+ new_seg = obj_mach_o_parse_section ();
+
+ if (new_seg != NULL)
+ {
+ demand_empty_rest_of_line ();
+
+ subseg_set (new_seg, 0);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
+ }
}
static segT
@@ -443,17 +465,23 @@ static const char * const known_sections[] =
static void
obj_mach_o_known_section (int sect_index)
{
- segT section;
+ segT new_seg;
+ segT old_seg = now_seg;
#ifdef md_flush_pending_output
md_flush_pending_output ();
#endif
- section = obj_mach_o_segT_from_bfd_name
(known_sections[sect_index], 1);
- if (section != NULL)
- subseg_set (section, 0);
+ new_seg = obj_mach_o_segT_from_bfd_name
(known_sections[sect_index], 1);
+ if (new_seg != NULL)
+ {
+ subseg_set (new_seg, 0);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
+ }
/* else, we leave the section as it was; there was a fatal error
anyway. */
+ demand_empty_rest_of_line ();
}
static const char * const objc_sections[] =
@@ -491,22 +519,25 @@ static const char * const objc_sections[] =
static void
obj_mach_o_objc_section (int sect_index)
{
- segT section;
+ segT new_seg;
+ segT old_seg = now_seg;
#ifdef md_flush_pending_output
md_flush_pending_output ();
#endif
- section = obj_mach_o_segT_from_bfd_name (objc_sections[sect_index],
1);
- if (section != NULL)
+ new_seg = obj_mach_o_segT_from_bfd_name (objc_sections[sect_index],
1);
+ if (new_seg != NULL)
{
obj_mach_o_seen_objc_section = 1; /* We need to ensure that
certain
sections are present and in the
right order. */
- subseg_set (section, 0);
+ subseg_set (new_seg, 0);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
}
-
/* else, we leave the section as it was; there was a fatal error
anyway. */
+ demand_empty_rest_of_line ();
}
/* Debug section directives. */
@@ -536,17 +567,22 @@ static const char * const debug_sections[] =
static void
obj_mach_o_debug_section (int sect_index)
{
- segT section;
+ segT new_seg;
+ segT old_seg = now_seg;
#ifdef md_flush_pending_output
md_flush_pending_output ();
#endif
- section = obj_mach_o_segT_from_bfd_name
(debug_sections[sect_index], 1);
- if (section != NULL)
- subseg_set (section, 0);
-
+ new_seg = obj_mach_o_segT_from_bfd_name
(debug_sections[sect_index], 1);
+ if (new_seg != NULL)
+ {
+ subseg_set (new_seg, 0);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
+ }
/* else, we leave the section as it was; there was a fatal error
anyway. */
+ demand_empty_rest_of_line ();
}
/* This could be moved to the tc-xx files, but there is so little
dependency
@@ -584,22 +620,25 @@ static void
obj_mach_o_opt_tgt_section (int sect_index)
{
const struct opt_tgt_sect *tgtsct = &tgt_sections[sect_index];
- segT section;
+ segT new_seg;
+ segT old_seg = now_seg;
#ifdef md_flush_pending_output
md_flush_pending_output ();
#endif
- section = obj_mach_o_segT_from_bfd_name (tgtsct->name, 0);
- if (section == NULL)
+ new_seg = obj_mach_o_segT_from_bfd_name (tgtsct->name, 0);
+ if (new_seg == NULL)
{
as_bad (_("%s is not used for the selected target"), tgtsct-
>name);
/* Leave the section as it is. */
}
else
{
- bfd_mach_o_section *mo_sec = bfd_mach_o_get_mach_o_section
(section);
- subseg_set (section, 0);
+ bfd_mach_o_section *mo_sec = bfd_mach_o_get_mach_o_section
(new_seg);
+ subseg_set (new_seg, 0);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
#if defined (TC_I386)
mo_sec->reserved2 = tgtsct->x86_val;
#elif defined (TC_PPC)
@@ -608,26 +647,14 @@ obj_mach_o_opt_tgt_section (int sect_index)
mo_sec->reserved2 = 0;
#endif
}
+ demand_empty_rest_of_line ();
}
-/* We don't necessarily have the three 'base' sections on mach-o.
- Normally, we would start up with only the 'text' section defined.
- However, even that can be suppressed with (TODO) c/l option "-n".
- Thus, we have to be able to create all three sections on-demand. */
-
-static void
-obj_mach_o_base_section (int sect_index)
+static segT
+obj_mach_o_get_base_section (int sect_index)
{
segT section;
-#ifdef md_flush_pending_output
- md_flush_pending_output ();
-#endif
-
- /* We don't support numeric (or any other) qualifications on the
- well-known section shorthands. */
- demand_empty_rest_of_line ();
-
switch (sect_index)
{
/* Handle the three sections that are globally known within GAS.
@@ -659,10 +686,39 @@ obj_mach_o_base_section (int sect_index)
break;
default:
as_fatal (_("internal error: base section index out of
range"));
- return;
+ return NULL;
break;
}
- subseg_set (section, 0);
+ return section;
+}
+
+/* We don't necessarily have the three 'base' sections on mach-o.
+ Normally, we would start up with only the 'text' section defined.
+ However, even that can be suppressed with (TODO) c/l option "-n".
+ Thus, we have to be able to create all three sections on-demand. */
+
+static void
+obj_mach_o_base_section (int sect_index)
+{
+ segT new_seg;
+ segT old_seg = now_seg;
+
+#ifdef md_flush_pending_output
+ md_flush_pending_output ();
+#endif
+
+ new_seg = obj_mach_o_get_base_section (sect_index);
+ if (new_seg != NULL)
+ {
+ subseg_set (new_seg, 0);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
+ }
+ /* else, we leave the section as it was; there was a fatal error
anyway. */
+
+ /* We don't support numeric (or any other) qualifications on
canonical
+ section names. */
+ demand_empty_rest_of_line ();
}
/* This finishes off parsing a .comm or .lcomm statement, which both
can have
@@ -718,7 +774,31 @@ obj_mach_o_common_parse (int is_local, symbolS
*symbolP,
static void
obj_mach_o_comm (int is_local)
{
+ segT old_seg = now_seg;
s_comm_internal (is_local, obj_mach_o_common_parse);
+ if (now_seg != old_seg)
+ previous_section = old_seg;
+}
+
+static void
+obj_mach_o_previous (int ignore ATTRIBUTE_UNUSED)
+{
+ segT old_prev;
+
+#ifdef md_flush_pending_output
+ md_flush_pending_output ();
+#endif
+
+ if (previous_section == 0)
+ {
+ as_warn (_(".previous, but no section switch seen; ignored"));
+ return;
+ }
+
+ old_prev = previous_section;
+ previous_section = now_seg;
+ subseg_set (old_prev, 0);
+ demand_empty_rest_of_line ();
}
/* Set properties that apply to the whole file. At present, the only
@@ -838,6 +918,9 @@ const pseudo_typeS mach_o_pseudo_table[] =
{ "section", obj_mach_o_section, 0},
+ /* Support the elf-style previous. */
+ { "previous", obj_mach_o_previous, 0},
+
/* Symbol-related. */
{ "indirect_symbol", obj_mach_o_placeholder, 0},
{ "weak_definition", obj_mach_o_placeholder, 0},
diff --git a/gas/testsuite/gas/mach-o/previous-1.d b/gas/testsuite/gas/
mach-o/previous-1.d
new file mode 100644
index 0000000..64d4ee5
--- /dev/null
+++ b/gas/testsuite/gas/mach-o/previous-1.d
@@ -0,0 +1,8 @@
+#objdump: -t
+.*: +file format mach-o.*
+#...
+SYMBOL TABLE:
+(00000000)?00000000 g.*0f SECT.*01 0000 \[.text\] a
+(00000000)?00000000 g.*0f SECT.*02 0000 \[.data\] a1
+(00000000)?00000001 g.*0f SECT.*01 0000 \[.text\] a2
+(00000000)?00000001 g.*0f SECT.*02 0000 \[.data\] a3
\ No newline at end of file
diff --git a/gas/testsuite/gas/mach-o/previous-1.s b/gas/testsuite/gas/
mach-o/previous-1.s
new file mode 100644
index 0000000..5522db7
--- /dev/null
+++ b/gas/testsuite/gas/mach-o/previous-1.s
@@ -0,0 +1,20 @@
+ .text
+
+ .globl a
+a: .space 1
+
+ .data
+
+ .globl a1
+a1: .space 1
+
+ .previous
+
+ .globl a2
+a2: .space 1
+
+ .previous
+
+ .globl a3
+a3: .space 1
+
diff --git a/gas/testsuite/gas/mach-o/warn-prev-1.s b/gas/testsuite/
gas/mach-o/warn-prev-1.s
new file mode 100644
index 0000000..fd0c0b5
--- /dev/null
+++ b/gas/testsuite/gas/mach-o/warn-prev-1.s
@@ -0,0 +1,5 @@
+# { dg-do assemble }
+
+ .previous
+
+# { dg-warning ".previous, but no section switch seen; ignored"
"" { target *-*-darwin*} 3 }
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