/* subsegs.c - subsegments -
Copyright (C) 1987-2015 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to the Free
Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
02110-1301, USA. */
/* Segments & sub-segments. */
#include "as.h"
#include "subsegs.h"
#include "obstack.h"
frchainS *frchain_now;
static struct obstack frchains;
static fragS dummy_frag;
void
subsegs_begin (void)
{
obstack_begin (&frchains, chunksize);
#if __GNUC__ >= 2
obstack_alignment_mask (&frchains) = __alignof__ (frchainS) - 1;
#endif
frchain_now = NULL; /* Warn new_subseg() that we are booting. */
frag_now = &dummy_frag;
}
/*
* subseg_change()
*
* Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the
* subsegment. If we are already in the correct subsegment, change nothing.
* This is used eg as a worker for subseg_set [which does make a new frag_now]
* and for changing segments after we have read the source. We construct eg
* fixSs even after the source file is read, so we do have to keep the
* segment context correct.
*/
void
subseg_change (segT seg, int subseg)
{
segment_info_type *seginfo = seg_info (seg);
now_seg = seg;
now_subseg = subseg;
if (! seginfo)
{
seginfo = (segment_info_type *) xcalloc (1, sizeof (*seginfo));
seginfo->bfd_section = seg;
bfd_set_section_userdata (stdoutput, seg, seginfo);
}
}
static void
subseg_set_rest (segT seg, subsegT subseg)
{
frchainS *frcP; /* crawl frchain chain */
frchainS **lastPP; /* address of last pointer */
frchainS *newP; /* address of new frchain */
segment_info_type *seginfo;
mri_common_symbol = NULL;
if (frag_now && frchain_now)
frchain_now->frch_frag_now = frag_now;
gas_assert (frchain_now == 0
|| frchain_now->frch_last == frag_now);
subseg_change (seg, (int) subseg);
seginfo = seg_info (seg);
/* Attempt to find or make a frchain for that subsection.
We keep the list sorted by subsection number. */
for (frcP = *(lastPP = &seginfo->frchainP);
frcP != NULL;
frcP = *(lastPP = &frcP->frch_next))
if (frcP->frch_subseg >= subseg)
break;
if (frcP == NULL || frcP->frch_subseg != subseg)
{
/* This should be the only code that creates a frchainS. */
newP = (frchainS *) obstack_alloc (&frchains, sizeof (frchainS));
newP->frch_subseg = subseg;
newP->fix_root = NULL;
newP->fix_tail = NULL;
obstack_begin (&newP->frch_obstack, chunksize);
#if __GNUC__ >= 2
obstack_alignment_mask (&newP->frch_obstack) = __alignof__ (fragS) - 1;
#endif
newP->frch_frag_now = frag_alloc (&newP->frch_obstack);
newP->frch_frag_now->fr_type = rs_fill;
newP->frch_cfi_data = NULL;
newP->frch_root = newP->frch_last = newP->frch_frag_now;
*lastPP = newP;
newP->frch_next = frcP;
frcP = newP;
}
frchain_now = frcP;
frag_now = frcP->frch_frag_now;
gas_assert (frchain_now->frch_last == frag_now);
}
/*
* subseg_set(segT, subsegT)
*
* If you attempt to change to the current subsegment, nothing happens.
*
* In: segT, subsegT code for new subsegment.
* frag_now -> incomplete frag for current subsegment.
* If frag_now==NULL, then there is no old, incomplete frag, so
* the old frag is not closed off.
*
* Out: now_subseg, now_seg updated.
* Frchain_now points to the (possibly new) struct frchain for this
* sub-segment.
*/
segT
subseg_get (const char *segname, int force_new)
{
segT secptr;
segment_info_type *seginfo;
const char *now_seg_name = (now_seg
? bfd_get_section_name (stdoutput, now_seg)
: 0);
if (!force_new
&& now_seg_name
&& (now_seg_name == segname
|| !strcmp (now_seg_name
, segname
))) return now_seg;
if (!force_new)
secptr = bfd_make_section_old_way (stdoutput, segname);
else
secptr = bfd_make_section_anyway (stdoutput, segname);
seginfo = seg_info (secptr);
if (! seginfo)
{
secptr->output_section = secptr;
seginfo = (segment_info_type *) xcalloc (1, sizeof (*seginfo));
seginfo->bfd_section = secptr;
bfd_set_section_userdata (stdoutput, secptr, seginfo);
}
return secptr;
}
segT
subseg_new (const char *segname, subsegT subseg)
{
segT secptr;
secptr = subseg_get (segname, 0);
subseg_set_rest (secptr, subseg);
return secptr;
}
/* Like subseg_new, except a new section is always created, even if
a section with that name already exists. */
segT
subseg_force_new (const char *segname, subsegT subseg)
{
segT secptr;
secptr = subseg_get (segname, 1);
subseg_set_rest (secptr, subseg);
return secptr;
}
void
subseg_set (segT secptr, subsegT subseg)
{
if (! (secptr == now_seg && subseg == now_subseg))
subseg_set_rest (secptr, subseg);
mri_common_symbol = NULL;
}
#ifndef obj_sec_sym_ok_for_reloc
#define obj_sec_sym_ok_for_reloc(SEC) 0
#endif
symbolS *
section_symbol (segT sec)
{
segment_info_type *seginfo = seg_info (sec);
symbolS *s;
if (seginfo == 0)
if (seginfo->sym)
return seginfo->sym;
#ifndef EMIT_SECTION_SYMBOLS
#define EMIT_SECTION_SYMBOLS 1
#endif
if (! EMIT_SECTION_SYMBOLS || symbol_table_frozen)
{
/* Here we know it won't be going into the symbol table. */
s = symbol_create (sec->symbol->name, sec, 0, &zero_address_frag);
}
else
{
segT seg;
s = symbol_find (sec->symbol->name);
/* We have to make sure it is the right symbol when we
have multiple sections with the same section name. */
if (s == NULL
|| ((seg = S_GET_SEGMENT (s)) != sec
&& seg != undefined_section))
s = symbol_new (sec->symbol->name, sec, 0, &zero_address_frag);
else if (seg == undefined_section)
{
S_SET_SEGMENT (s, sec);
symbol_set_frag (s, &zero_address_frag);
}
}
S_CLEAR_EXTERNAL (s);
/* Use the BFD section symbol, if possible. */
if (obj_sec_sym_ok_for_reloc (sec))
symbol_set_bfdsym (s, sec->symbol);
else
symbol_get_bfdsym (s)->flags |= BSF_SECTION_SYM;
seginfo->sym = s;
return s;
}
/* Return whether the specified segment is thought to hold text. */
int
subseg_text_p (segT sec)
{
return (bfd_get_section_flags (stdoutput, sec) & SEC_CODE) != 0;
}
/* Return non zero if SEC has at least one byte of data. It is
possible that we'll return zero even on a non-empty section because
we don't know all the fragment types, and it is possible that an
fr_fix == 0 one still contributes data. Think of this as
seg_definitely_not_empty_p. */
int
seg_not_empty_p (segT sec ATTRIBUTE_UNUSED)
{
segment_info_type *seginfo = seg_info (sec);
frchainS *chain;
fragS *frag;
if (!seginfo)
return 0;
for (chain = seginfo->frchainP; chain; chain = chain->frch_next)
{
for (frag = chain->frch_root; frag; frag = frag->fr_next)
if (frag->fr_fix)
return 1;
if (obstack_next_free (&chain->frch_obstack)
!= chain->frch_last->fr_literal)
return 1;
}
return 0;
}
void
subsegs_print_statistics (FILE *file)
{
frchainS *frchp;
asection *s;
for (s = stdoutput->sections; s; s = s->next)
{
segment_info_type *seginfo;
/* Skip gas-internal sections. */
if (segment_name (s)[0] == '*')
continue;
seginfo = seg_info (s);
if (!seginfo)
continue;
for (frchp = seginfo->frchainP; frchp; frchp = frchp->frch_next)
{
int count = 0;
fragS *fragp;
for (fragp = frchp->frch_root; fragp; fragp = fragp->fr_next)
count++;
fprintf (file
, "\t%p %-10s\t%10d frags\n", (void *) frchp
, segment_name (s), count);
}
}
}
/* end of subsegs.c */