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/* subsegs.c - subsegments -
Copyright (C) 1987, 1990, 1991, 1992, 1993, 1994
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 2, 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, 675 Mass Ave, Cambridge, MA 02139, USA. */
/*
* Segments & sub-segments.
*/
#include "as.h"
#include "subsegs.h"
#include "obstack.h"
frchainS *frchain_root, *frchain_now;
#ifndef BFD_ASSEMBLER
#ifdef MANY_SEGMENTS
segment_info_type segment_info[SEG_MAXIMUM_ORDINAL];
#else
/* Commented in "subsegs.h". */
frchainS *data0_frchainP, *bss0_frchainP;
#endif /* MANY_SEGMENTS */
char *const seg_name[] =
{
"absolute",
#ifdef MANY_SEGMENTS
"e0", "e1", "e2", "e3", "e4", "e5", "e6", "e7", "e8", "e9",
#else
"text",
"data",
"bss",
#endif /* MANY_SEGMENTS */
"unknown",
"ASSEMBLER-INTERNAL-LOGIC-ERROR!",
"expr",
"debug",
"transfert vector preload",
"transfert vector postload",
"register",
"",
}; /* Used by error reporters, dumpers etc. */
#endif /* BFD_ASSEMBLER */
static void subseg_set_rest PARAMS ((segT, subsegT));
void
subsegs_begin ()
{
/* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */
#if !defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
know (SEG_ABSOLUTE == 0);
know (SEG_TEXT == 1);
know (SEG_DATA == 2);
know (SEG_BSS == 3);
know (SEG_UNKNOWN == 4);
know (SEG_GOOF == 5);
know (SEG_EXPR == 6);
know (SEG_DEBUG == 7);
know (SEG_NTV == 8);
know (SEG_PTV == 9);
know (SEG_REGISTER == 10);
know (SEG_MAXIMUM_ORDINAL == SEG_REGISTER);
#endif
obstack_begin (&frags, 5000);
frchain_root = NULL;
frchain_now = NULL; /* Warn new_subseg() that we are booting. */
/* Fake up 1st frag. It won't be used=> is ok if obstack...
pads the end of it for alignment. */
frag_now = (fragS *) obstack_alloc (&frags, SIZEOF_STRUCT_FRAG);
memset (frag_now, 0, SIZEOF_STRUCT_FRAG);
#ifndef BFD_ASSEMBLER
/* This 1st frag will not be in any frchain.
We simply give subseg_new somewhere to scribble. */
now_subseg = 42; /* Lie for 1st call to subseg_new. */
#ifdef MANY_SEGMENTS
{
int i;
for (i = SEG_E0; i < SEG_UNKNOWN; i++)
{
subseg_set (i, 0);
segment_info[i].frchainP = frchain_now;
}
}
#else
subseg_set (SEG_DATA, 0); /* .data 0 */
data0_frchainP = frchain_now;
subseg_set (SEG_BSS, 0);
bss0_frchainP = frchain_now;
#endif /* ! MANY_SEGMENTS */
#endif /* ! BFD_ASSEMBLER */
}
/*
* 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 (seg, subseg)
register segT seg;
register int subseg;
{
now_seg = seg;
now_subseg = subseg;
#ifdef BFD_ASSEMBLER
{
segment_info_type *seginfo;
seginfo = (segment_info_type *) bfd_get_section_userdata (stdoutput, seg);
if (! seginfo)
{
seginfo = (segment_info_type *) xmalloc (sizeof (*seginfo));
if (! seginfo)
abort ();
seginfo->fix_root = NULL;
seginfo->fix_tail = NULL;
seginfo->bfd_section = seg;
seginfo->sym = 0;
bfd_set_section_userdata (stdoutput, seg, (char *) seginfo);
}
}
#else
#ifdef MANY_SEGMENTS
seg_fix_rootP = &segment_info[seg].fix_root;
seg_fix_tailP = &segment_info[seg].fix_tail;
#else
if (seg == SEG_DATA)
{
seg_fix_rootP = &data_fix_root;
seg_fix_tailP = &data_fix_tail;
}
else if (seg == SEG_TEXT)
{
seg_fix_rootP = &text_fix_root;
seg_fix_tailP = &text_fix_tail;
}
else
{
know (seg == SEG_BSS);
seg_fix_rootP = &bss_fix_root;
seg_fix_tailP = &bss_fix_tail;
}
#endif
#endif
}
static void
subseg_set_rest (seg, subseg)
segT seg;
subsegT subseg;
{
long tmp; /* JF for obstack alignment hacking */
register frchainS *frcP; /* crawl frchain chain */
register frchainS **lastPP; /* address of last pointer */
frchainS *newP; /* address of new frchain */
register fragS *former_last_fragP;
register fragS *new_fragP;
if (frag_now) /* If not bootstrapping. */
{
frag_now->fr_fix = (char*) obstack_next_free (&frags) - frag_now->fr_literal;
frag_wane (frag_now); /* Close off any frag in old subseg. */
}
/*
* It would be nice to keep an obstack for each subsegment, if we swap
* subsegments a lot. Hence we would have much fewer frag_wanes().
*/
{
obstack_finish (&frags);
/*
* If we don't do the above, the next object we put on obstack frags
* will appear to start at the fr_literal of the current frag.
* Also, above ensures that the next object will begin on a
* address that is aligned correctly for the engine that runs
* this program.
*/
}
subseg_change (seg, (int) subseg);
/*
* Attempt to find or make a frchain for that sub seg.
* Crawl along chain of frchainSs, begins @ frchain_root.
* If we need to make a frchainS, link it into correct
* position of chain rooted in frchain_root.
*/
for (frcP = *(lastPP = &frchain_root);
frcP && (int) (frcP->frch_seg) <= (int) seg;
frcP = *(lastPP = &frcP->frch_next))
{
if ((int) (frcP->frch_seg) == (int) seg
&& frcP->frch_subseg >= subseg)
{
break;
}
}
/*
* frcP: Address of the 1st frchainS in correct segment with
* frch_subseg >= subseg.
* We want to either use this frchainS, or we want
* to insert a new frchainS just before it.
*
* If frcP==NULL, then we are at the end of the chain
* of frchainS-s. A NULL frcP means we fell off the end
* of the chain looking for a
* frch_subseg >= subseg, so we
* must make a new frchainS.
*
* If we ever maintain a pointer to
* the last frchainS in the chain, we change that pointer
* ONLY when frcP==NULL.
*
* lastPP: Address of the pointer with value frcP;
* Never NULL.
* May point to frchain_root.
*
*/
if (!frcP
|| ((int) (frcP->frch_seg) > (int) seg
|| frcP->frch_subseg > subseg)) /* Kinky logic only works with 2 segments. */
{
/*
* This should be the only code that creates a frchainS.
*/
newP = (frchainS *) obstack_alloc (&frags, sizeof (frchainS));
memset (newP, 0, sizeof (frchainS));
/* This begines on a good boundary because a obstack_done()
preceeded it. It implies an obstack_done(), so we expect
the next object allocated to begin on a correct boundary. */
*lastPP = newP;
newP->frch_next = frcP; /* perhaps NULL */
(frcP = newP)->frch_subseg = subseg;
newP->frch_seg = seg;
newP->frch_last = NULL;
#ifdef BFD_ASSEMBLER
newP->fix_root = NULL;
newP->fix_tail = NULL;
#endif
}
/*
* Here with frcP ->ing to the frchainS for subseg.
*/
frchain_now = frcP;
/*
* Make a fresh frag for the subsegment.
*/
/* We expect this to happen on a correct boundary since it was
proceeded by a obstack_done(). */
tmp = obstack_alignment_mask (&frags); /* JF disable alignment */
obstack_alignment_mask (&frags) = 0;
frag_now = (fragS *) obstack_alloc (&frags, SIZEOF_STRUCT_FRAG);
memset (frag_now, 0, SIZEOF_STRUCT_FRAG);
obstack_alignment_mask (&frags) = tmp;
/* But we want any more chars to come immediately after the
structure we just made. */
new_fragP = frag_now;
new_fragP->fr_next = NULL;
/*
* Append new frag to current frchain.
*/
former_last_fragP = frcP->frch_last;
if (former_last_fragP)
{
know (former_last_fragP->fr_next == NULL);
know (frchain_now->frch_root);
former_last_fragP->fr_next = new_fragP;
}
else
{
frcP->frch_root = new_fragP;
}
frcP->frch_last = new_fragP;
}
/*
* 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.
* Frchain_root updated if needed.
*/
#ifndef BFD_ASSEMBLER
segT
subseg_new (segname, subseg)
const char *segname;
subsegT subseg;
{
int i;
for (i = 0; i < (int) SEG_MAXIMUM_ORDINAL; i++)
{
const char *s;
s = segment_name ((segT) i);
if (strcmp (segname, s) == 0
|| (segname[0] == '.'
&& strcmp (segname + 1, s) == 0))
{
subseg_set ((segT) i, subseg);
return (segT) i;
}
#ifdef obj_segment_name
s = obj_segment_name ((segT) i);
if (strcmp (segname, s) == 0
|| (segname[0] == '.'
&& strcmp (segname + 1, s) == 0))
{
subseg_set ((segT) i, subseg);
return (segT) i;
}
#endif
}
#ifdef obj_add_segment
{
segT new_seg;
new_seg = obj_add_segment (segname);
subseg_set (new_seg, subseg);
return new_seg;
}
#else
as_bad ("Attempt to switch to nonexistent segment \"%s\"", segname);
return now_seg;
#endif
}
void
subseg_set (seg, subseg) /* begin assembly for a new sub-segment */
register segT seg; /* SEG_DATA or SEG_TEXT */
register subsegT subseg;
{
#ifndef MANY_SEGMENTS
know (seg == SEG_DATA || seg == SEG_TEXT || seg == SEG_BSS);
#endif
if (seg != now_seg || subseg != now_subseg)
{ /* we just changed sub-segments */
subseg_set_rest (seg, subseg);
}
}
#else /* BFD_ASSEMBLER */
segT
subseg_get (segname, force_new)
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 *) xmalloc (sizeof (*seginfo));
memset ((char *) seginfo, 0, sizeof(seginfo));
seginfo->fix_root = NULL;
seginfo->fix_tail = NULL;
seginfo->bfd_section = secptr;
bfd_set_section_userdata (stdoutput, secptr, (char *) seginfo);
seginfo->frchainP = NULL;
seginfo->lineno_list_head = seginfo->lineno_list_tail = NULL;
seginfo->sym = NULL;
seginfo->dot = NULL;
}
return secptr;
}
segT
subseg_new (segname, subseg)
const char *segname;
subsegT subseg;
{
segT secptr;
segment_info_type *seginfo;
secptr = subseg_get (segname, 0);
subseg_set_rest (secptr, subseg);
seginfo = seg_info (secptr);
if (! seginfo->frchainP)
seginfo->frchainP = frchain_now;
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 (segname, subseg)
const char *segname;
subsegT subseg;
{
segT secptr;
segment_info_type *seginfo;
secptr = subseg_get (segname, 1);
subseg_set_rest (secptr, subseg);
seginfo = seg_info (secptr);
if (! seginfo->frchainP)
seginfo->frchainP = frchain_now;
return secptr;
}
void
subseg_set (secptr, subseg)
segT secptr;
subsegT subseg;
{
if (! (secptr == now_seg && subseg == now_subseg))
subseg_set_rest (secptr, subseg);
}
#ifndef obj_sec_sym_ok_for_reloc
#define obj_sec_sym_ok_for_reloc(SEC) 0
#endif
symbolS *
section_symbol (sec)
segT sec;
{
segment_info_type *seginfo = seg_info (sec);
symbolS *s;
if (seginfo == 0)
abort ();
if (seginfo->sym)
return seginfo->sym;
s = symbol_find (sec->name);
if (!s)
{
s = symbol_new (sec->name, sec, 0, &zero_address_frag);
S_CLEAR_EXTERNAL (s);
/* Use the BFD section symbol, if possible. */
if (obj_sec_sym_ok_for_reloc (sec))
s->bsym = sec->symbol;
}
seginfo->sym = s;
return s;
}
#endif /* BFD_ASSEMBLER */
/* end of subsegs.c */
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