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[Patch gas/mach-o 2/2] implement mach-o subsections-via-symbols.
- From: Iain Sandoe <developer at sandoe-acoustics dot co dot uk>
- To: binutils Development <binutils at sourceware dot org>
- Cc: Tristan Gingold <gingold at adacore dot com>
- Date: Fri, 17 Feb 2012 17:21:22 +0000
- Subject: [Patch gas/mach-o 2/2] implement mach-o subsections-via-symbols.
This is the bulk of the 'work' associated with the implementation.
I've re-named a couple of routines to keep to "obj_mach_o_xxx" and
tried to ensure that the order of routines in the main file and header
match up. Our code is growing quite fast and maybe they got a little
out of synch (new culpa, I'm sure ;)).
OK for trunk?
Iain
gas:
* config/obj-macho.c (obj_mach_o_frob_colon): New.
(obj_mach_o_frob_label): Record sub-section labels.
(obj_mach_o_frob_symbol): Rename from obj_macho_frob_symbol.
(obj_mach_o_set_subsections): New.
(obj_mach_o_pre_relax_hook): New.
(obj_mach_o_in_different_subsection): New.
(obj_mach_o_force_reloc_sub_same): New.
(obj_mach_o_force_reloc_sub_local): New.
(obj_mach_o_force_reloc): New.
* config/obj-macho.h (OBJ_SYMFIELD_TYPE): New.
(obj_frob_colon): New Define.
(obj_mach_o_frob_label): Renamed.
(obj_mach_o_frob_symbol): Renamed.
(OBJ_FRAG_TYPE): New.
(obj_mach_o_in_different_subsection, obj_mach_o_force_reloc,
obj_mach_o_force_reloc_sub_same,
obj_mach_o_force_reloc_sub_local): New declarations.
gas/config/obj-macho.c | 199 +++++++++++++++++++++++++++++++++++++++
+--------
gas/config/obj-macho.h | 49 ++++++++++---
2 files changed, 205 insertions(+), 43 deletions(-)
diff --git a/gas/config/obj-macho.c b/gas/config/obj-macho.c
index 2a2e47d..632eafa 100644
--- a/gas/config/obj-macho.c
+++ b/gas/config/obj-macho.c
@@ -1331,6 +1331,18 @@ obj_mach_o_type_for_symbol (bfd_mach_o_asymbol
*s)
return BFD_MACH_O_N_SECT;
}
+void
+obj_mach_o_frob_colon (const char *name)
+{
+ if (!bfd_is_local_label_name (stdoutput, name))
+ {
+ /* A non-local label will create a new subsection, so start a new
+ frag. */
+ frag_wane (frag_now);
+ frag_new (0);
+ }
+}
+
/* We need to check the correspondence between some kinds of symbols
and their
sections. Common and BSS vars will seen via the obj_macho_comm()
function.
@@ -1345,13 +1357,21 @@ obj_mach_o_type_for_symbol (bfd_mach_o_asymbol
*s)
are possibly incompatible with the section etc. that the symbol
is defined
in. */
-void obj_macho_frob_label (struct symbol *sp)
+void obj_mach_o_frob_label (struct symbol *sp)
{
bfd_mach_o_asymbol *s;
unsigned base_type;
bfd_mach_o_section *sec;
int sectype = -1;
+ if (!bfd_is_local_label_name (stdoutput, S_GET_NAME (sp)))
+ {
+ /* If this is a non-local label, it should have started a new
sub-
+ section. */
+ gas_assert (frag_now->obj_frag_data.subsection == NULL);
+ frag_now->obj_frag_data.subsection = sp;
+ }
+
/* Leave local symbols alone. */
if (S_IS_LOCAL (sp))
@@ -1392,7 +1412,7 @@ void obj_macho_frob_label (struct symbol *sp)
(e.g. global + weak_def). */
int
-obj_macho_frob_symbol (struct symbol *sp)
+obj_mach_o_frob_symbol (struct symbol *sp)
{
bfd_mach_o_asymbol *s;
unsigned base_type;
@@ -1483,6 +1503,95 @@ obj_macho_frob_symbol (struct symbol *sp)
return 0;
}
+/* Support stabs for mach-o. */
+
+void
+obj_mach_o_process_stab (int what, const char *string,
+ int type, int other, int desc)
+{
+ symbolS *symbolP;
+ bfd_mach_o_asymbol *s;
+
+ switch (what)
+ {
+ case 'd':
+ symbolP = symbol_new ("", now_seg, frag_now_fix (), frag_now);
+ /* Special stabd NULL name indicator. */
+ S_SET_NAME (symbolP, NULL);
+ break;
+
+ case 'n':
+ case 's':
+ symbolP = symbol_new (string, undefined_section, (valueT) 0,
+ &zero_address_frag);
+ pseudo_set (symbolP);
+ break;
+
+ default:
+ as_bad(_("unrecognized stab type '%c'"), (char)what);
+ abort ();
+ break;
+ }
+
+ s = (bfd_mach_o_asymbol *) symbol_get_bfdsym (symbolP);
+ s->n_type = type;
+ s->n_desc = desc;
+ /* For stabd, this will eventually get overwritten by the section
number. */
+ s->n_sect = other;
+
+ /* It's a debug symbol. */
+ s->symbol.flags |= BSF_DEBUGGING;
+}
+
+/* Here we count up frags in each subsection (where a sub-section is
defined
+ as starting with a non-local symbol).
+ Note that, if there are no non-local symbols in a section, all the
frags will
+ be attached as one anonymous subsection. */
+
+static void
+obj_mach_o_set_subsections (bfd *abfd ATTRIBUTE_UNUSED,
+ asection *sec,
+ void *unused ATTRIBUTE_UNUSED)
+{
+ segment_info_type *seginfo = seg_info (sec);
+ symbolS *cur_subsection = NULL;
+ struct obj_mach_o_symbol_data *cur_subsection_data = NULL;
+ fragS *frag;
+ frchainS *chain;
+
+ /* Protect against sections not created by gas. */
+ if (seginfo == NULL)
+ return;
+
+ /* Attach every frag to a subsection. */
+ for (chain = seginfo->frchainP; chain != NULL; chain = chain-
>frch_next)
+ for (frag = chain->frch_root; frag != NULL; frag = frag->fr_next)
+ {
+ if (frag->obj_frag_data.subsection == NULL)
+ frag->obj_frag_data.subsection = cur_subsection;
+ else
+ {
+ cur_subsection = frag->obj_frag_data.subsection;
+ cur_subsection_data = symbol_get_obj (cur_subsection);
+ cur_subsection_data->subsection_size = 0;
+ }
+ if (cur_subsection_data != NULL)
+ {
+ /* Update subsection size. */
+ cur_subsection_data->subsection_size += frag->fr_fix;
+ }
+ }
+}
+
+/* Handle mach-o subsections-via-symbols counting up frags belonging
to each
+ sub-section. */
+
+void
+obj_mach_o_pre_relax_hook (void)
+{
+ bfd_map_over_sections (stdoutput, obj_mach_o_set_subsections, (char
*) 0);
+}
+
/* Zerofill and GB Zerofill sections must be sorted to follow all
other
sections in their segments.
@@ -1706,42 +1815,66 @@ obj_mach_o_reorder_section_relocs (asection
*sec, arelent **rels, unsigned int n
bfd_set_reloc (stdoutput, sec, rels, n);
}
-/* Support stabs for mach-o. */
-
-void
-obj_mach_o_process_stab (int what, const char *string,
- int type, int other, int desc)
+int
+obj_mach_o_in_different_subsection (symbolS *a, symbolS *b)
{
- symbolS *symbolP;
- bfd_mach_o_asymbol *s;
+ fragS *fa;
+ fragS *fb;
- switch (what)
+ if (S_GET_SEGMENT (a) != S_GET_SEGMENT (b)
+ || !S_IS_DEFINED (a)
+ || !S_IS_DEFINED (b))
{
- case 'd':
- symbolP = symbol_new ("", now_seg, frag_now_fix (), frag_now);
- /* Special stabd NULL name indicator. */
- S_SET_NAME (symbolP, NULL);
- break;
-
- case 'n':
- case 's':
- symbolP = symbol_new (string, undefined_section, (valueT) 0,
- &zero_address_frag);
- pseudo_set (symbolP);
- break;
+ /* Not in the same segment, or undefined symbol. */
+ return 1;
+ }
- default:
- as_bad(_("unrecognized stab type '%c'"), (char)what);
- abort ();
- break;
+ fa = symbol_get_frag (a);
+ fb = symbol_get_frag (b);
+ if (fa == NULL || fb == NULL)
+ {
+ /* One of the symbols is not in a subsection. */
+ return 1;
}
- s = (bfd_mach_o_asymbol *) symbol_get_bfdsym (symbolP);
- s->n_type = type;
- s->n_desc = desc;
- /* For stabd, this will eventually get overwritten by the section
number. */
- s->n_sect = other;
+ return fa->obj_frag_data.subsection != fb->obj_frag_data.subsection;
+}
- /* It's a debug symbol. */
- s->symbol.flags |= BSF_DEBUGGING;
+int
+obj_mach_o_force_reloc_sub_same (fixS *fix, segT seg)
+{
+ if (! SEG_NORMAL (seg))
+ return 1;
+ return obj_mach_o_in_different_subsection (fix->fx_addsy, fix-
>fx_subsy);
+}
+
+int
+obj_mach_o_force_reloc_sub_local (fixS *fix, segT seg ATTRIBUTE_UNUSED)
+{
+ return obj_mach_o_in_different_subsection (fix->fx_addsy, fix-
>fx_subsy);
+}
+
+int
+obj_mach_o_force_reloc (fixS *fix)
+{
+ if (generic_force_reloc (fix))
+ return 1;
+
+ /* Force a reloc if the target is not in the same subsection.
+ FIXME: handle (a - b) where a and b belongs to the same
subsection ? */
+ if (fix->fx_addsy != NULL)
+ {
+ symbolS *subsec = fix->fx_frag->obj_frag_data.subsection;
+ symbolS *targ = fix->fx_addsy;
+
+ /* There might be no subsections at all. */
+ if (subsec == NULL)
+ return 0;
+
+ if (S_GET_SEGMENT (targ) == absolute_section)
+ return 0;
+
+ return obj_mach_o_in_different_subsection (targ, subsec);
+ }
+ return 0;
}
diff --git a/gas/config/obj-macho.h b/gas/config/obj-macho.h
index bb8daf9..b49038c 100644
--- a/gas/config/obj-macho.h
+++ b/gas/config/obj-macho.h
@@ -56,11 +56,36 @@ extern const pseudo_typeS mach_o_pseudo_table[];
#define obj_read_begin_hook() {;}
#define obj_symbol_new_hook(s) {;}
-#define obj_frob_label(s) obj_macho_frob_label(s)
-extern void obj_macho_frob_label (struct symbol *);
+#define EMIT_SECTION_SYMBOLS 0
+
+struct obj_mach_o_symbol_data
+{
+ /* If the symbol represents a subsection, this is the size of the
subsection.
+ This is used to check whether a local symbol belongs to a
subsection. */
+ valueT subsection_size;
+};
+#define OBJ_SYMFIELD_TYPE struct obj_mach_o_symbol_data
+
+#define obj_frob_colon obj_mach_o_frob_colon
+extern void obj_mach_o_frob_colon (const char *);
+
+/* Called when a label is defined. Mach-O uses this to create
subsections. */
+#define obj_frob_label obj_mach_o_frob_label
+extern void obj_mach_o_frob_label (symbolS *);
-#define obj_frob_symbol(s, punt) punt = obj_macho_frob_symbol(s)
-extern int obj_macho_frob_symbol (struct symbol *);
+#define obj_frob_symbol(s, punt) punt = obj_mach_o_frob_symbol(s)
+extern int obj_mach_o_frob_symbol (struct symbol *);
+
+struct obj_mach_o_frag_data
+{
+ /* Symbol that corresponds to the subsection. */
+ symbolS *subsection;
+};
+
+#define OBJ_FRAG_TYPE struct obj_mach_o_frag_data
+
+#define md_pre_relax_hook obj_mach_o_pre_relax_hook()
+extern void obj_mach_o_pre_relax_hook (void);
#define md_post_relax_hook obj_mach_o_post_relax_hook()
void obj_mach_o_post_relax_hook (void);
@@ -68,14 +93,18 @@ 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);
-void obj_mach_o_reorder_section_relocs (asection *, arelent **,
unsigned int);
+#define OBJ_PROCESS_STAB(SEG,W,S,T,O,D)
obj_mach_o_process_stab(W,S,T,O,D)
+extern void obj_mach_o_process_stab (int, const char *,int, int, int);
#define SET_SECTION_RELOCS(sec, relocs, n) \
obj_mach_o_reorder_section_relocs (sec, relocs, n)
-
-#define EMIT_SECTION_SYMBOLS 0
-
-#define OBJ_PROCESS_STAB(SEG,W,S,T,O,D)
obj_mach_o_process_stab(W,S,T,O,D)
-extern void obj_mach_o_process_stab (int, const char *,int, int, int);
+extern void obj_mach_o_reorder_section_relocs (asection *, arelent **,
+ unsigned int);
+
+struct fix;
+int obj_mach_o_in_different_subsection (symbolS *a, symbolS *b);
+int obj_mach_o_force_reloc (struct fix *fix);
+int obj_mach_o_force_reloc_sub_same (struct fix *fix, segT seg);
+int obj_mach_o_force_reloc_sub_local (struct fix *fix, segT seg);
#endif /* _OBJ_MACH_O_H */