386 lines
11 KiB
C
386 lines
11 KiB
C
/* frags.c - manage frags -
|
||
Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
|
||
1999, 2000
|
||
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, 59 Temple Place - Suite 330, Boston, MA
|
||
02111-1307, USA. */
|
||
|
||
#include "as.h"
|
||
#include "subsegs.h"
|
||
#include "obstack.h"
|
||
|
||
extern fragS zero_address_frag;
|
||
extern fragS bss_address_frag;
|
||
|
||
/* Initialization for frag routines. */
|
||
|
||
void
|
||
frag_init ()
|
||
{
|
||
zero_address_frag.fr_type = rs_fill;
|
||
bss_address_frag.fr_type = rs_fill;
|
||
}
|
||
|
||
/* Allocate a frag on the specified obstack.
|
||
Call this routine from everywhere else, so that all the weird alignment
|
||
hackery can be done in just one place. */
|
||
|
||
fragS *
|
||
frag_alloc (ob)
|
||
struct obstack *ob;
|
||
{
|
||
fragS *ptr;
|
||
int oalign;
|
||
|
||
(void) obstack_alloc (ob, 0);
|
||
oalign = obstack_alignment_mask (ob);
|
||
obstack_alignment_mask (ob) = 0;
|
||
ptr = (fragS *) obstack_alloc (ob, SIZEOF_STRUCT_FRAG);
|
||
obstack_alignment_mask (ob) = oalign;
|
||
memset (ptr, 0, SIZEOF_STRUCT_FRAG);
|
||
return ptr;
|
||
}
|
||
|
||
/* Try to augment current frag by nchars chars.
|
||
If there is no room, close of the current frag with a ".fill 0"
|
||
and begin a new frag. Unless the new frag has nchars chars available
|
||
do not return. Do not set up any fields of *now_frag. */
|
||
|
||
void
|
||
frag_grow (nchars)
|
||
unsigned int nchars;
|
||
{
|
||
if (obstack_room (&frchain_now->frch_obstack) < nchars)
|
||
{
|
||
unsigned int n;
|
||
long oldc;
|
||
|
||
frag_wane (frag_now);
|
||
frag_new (0);
|
||
oldc = frchain_now->frch_obstack.chunk_size;
|
||
frchain_now->frch_obstack.chunk_size = 2 * nchars + SIZEOF_STRUCT_FRAG;
|
||
if (frchain_now->frch_obstack.chunk_size > 0)
|
||
while ((n = obstack_room (&frchain_now->frch_obstack)) < nchars
|
||
&& (unsigned long) frchain_now->frch_obstack.chunk_size > nchars)
|
||
{
|
||
frag_wane (frag_now);
|
||
frag_new (0);
|
||
}
|
||
frchain_now->frch_obstack.chunk_size = oldc;
|
||
}
|
||
if (obstack_room (&frchain_now->frch_obstack) < nchars)
|
||
as_fatal (_("can't extend frag %u chars"), nchars);
|
||
}
|
||
|
||
/* Call this to close off a completed frag, and start up a new (empty)
|
||
frag, in the same subsegment as the old frag.
|
||
[frchain_now remains the same but frag_now is updated.]
|
||
Because this calculates the correct value of fr_fix by
|
||
looking at the obstack 'frags', it needs to know how many
|
||
characters at the end of the old frag belong to the maximal
|
||
variable part; The rest must belong to fr_fix.
|
||
It doesn't actually set up the old frag's fr_var. You may have
|
||
set fr_var == 1, but allocated 10 chars to the end of the frag;
|
||
In this case you pass old_frags_var_max_size == 10.
|
||
In fact, you may use fr_var for something totally unrelated to the
|
||
size of the variable part of the frag; None of the generic frag
|
||
handling code makes use of fr_var.
|
||
|
||
Make a new frag, initialising some components. Link new frag at end
|
||
of frchain_now. */
|
||
|
||
void
|
||
frag_new (old_frags_var_max_size)
|
||
/* Number of chars (already allocated on obstack frags) in
|
||
variable_length part of frag. */
|
||
int old_frags_var_max_size;
|
||
{
|
||
fragS *former_last_fragP;
|
||
frchainS *frchP;
|
||
|
||
assert (frchain_now->frch_last == frag_now);
|
||
|
||
/* Fix up old frag's fr_fix. */
|
||
frag_now->fr_fix = frag_now_fix_octets () - old_frags_var_max_size;
|
||
/* Make sure its type is valid. */
|
||
assert (frag_now->fr_type != 0);
|
||
|
||
/* This will align the obstack so the next struct we allocate on it
|
||
will begin at a correct boundary. */
|
||
obstack_finish (&frchain_now->frch_obstack);
|
||
frchP = frchain_now;
|
||
know (frchP);
|
||
former_last_fragP = frchP->frch_last;
|
||
assert (former_last_fragP != 0);
|
||
assert (former_last_fragP == frag_now);
|
||
frag_now = frag_alloc (&frchP->frch_obstack);
|
||
|
||
as_where (&frag_now->fr_file, &frag_now->fr_line);
|
||
|
||
/* Generally, frag_now->points to an address rounded up to next
|
||
alignment. However, characters will add to obstack frags
|
||
IMMEDIATELY after the struct frag, even if they are not starting
|
||
at an alignment address. */
|
||
former_last_fragP->fr_next = frag_now;
|
||
frchP->frch_last = frag_now;
|
||
|
||
#ifndef NO_LISTING
|
||
{
|
||
extern struct list_info_struct *listing_tail;
|
||
frag_now->line = listing_tail;
|
||
}
|
||
#endif
|
||
|
||
assert (frchain_now->frch_last == frag_now);
|
||
|
||
frag_now->fr_next = NULL;
|
||
}
|
||
|
||
/* Start a new frag unless we have n more chars of room in the current frag.
|
||
Close off the old frag with a .fill 0.
|
||
|
||
Return the address of the 1st char to write into. Advance
|
||
frag_now_growth past the new chars. */
|
||
|
||
char *
|
||
frag_more (nchars)
|
||
int nchars;
|
||
{
|
||
register char *retval;
|
||
|
||
if (now_seg == absolute_section)
|
||
{
|
||
as_bad (_("attempt to allocate data in absolute section"));
|
||
subseg_set (text_section, 0);
|
||
}
|
||
|
||
if (mri_common_symbol != NULL)
|
||
{
|
||
as_bad (_("attempt to allocate data in common section"));
|
||
mri_common_symbol = NULL;
|
||
}
|
||
|
||
frag_grow (nchars);
|
||
retval = obstack_next_free (&frchain_now->frch_obstack);
|
||
obstack_blank_fast (&frchain_now->frch_obstack, nchars);
|
||
return (retval);
|
||
}
|
||
|
||
/* Start a new frag unless we have max_chars more chars of room in the
|
||
current frag. Close off the old frag with a .fill 0.
|
||
|
||
Set up a machine_dependent relaxable frag, then start a new frag.
|
||
Return the address of the 1st char of the var part of the old frag
|
||
to write into. */
|
||
|
||
char *
|
||
frag_var (type, max_chars, var, subtype, symbol, offset, opcode)
|
||
relax_stateT type;
|
||
int max_chars;
|
||
int var;
|
||
relax_substateT subtype;
|
||
symbolS *symbol;
|
||
offsetT offset;
|
||
char *opcode;
|
||
{
|
||
register char *retval;
|
||
|
||
frag_grow (max_chars);
|
||
retval = obstack_next_free (&frchain_now->frch_obstack);
|
||
obstack_blank_fast (&frchain_now->frch_obstack, max_chars);
|
||
frag_now->fr_var = var;
|
||
frag_now->fr_type = type;
|
||
frag_now->fr_subtype = subtype;
|
||
frag_now->fr_symbol = symbol;
|
||
frag_now->fr_offset = offset;
|
||
frag_now->fr_opcode = opcode;
|
||
#ifdef USING_CGEN
|
||
frag_now->fr_cgen.insn = 0;
|
||
frag_now->fr_cgen.opindex = 0;
|
||
frag_now->fr_cgen.opinfo = 0;
|
||
#endif
|
||
#ifdef TC_FRAG_INIT
|
||
TC_FRAG_INIT (frag_now);
|
||
#endif
|
||
as_where (&frag_now->fr_file, &frag_now->fr_line);
|
||
frag_new (max_chars);
|
||
return (retval);
|
||
}
|
||
|
||
/* OVE: This variant of frag_var assumes that space for the tail has been
|
||
allocated by caller.
|
||
No call to frag_grow is done. */
|
||
|
||
char *
|
||
frag_variant (type, max_chars, var, subtype, symbol, offset, opcode)
|
||
relax_stateT type;
|
||
int max_chars;
|
||
int var;
|
||
relax_substateT subtype;
|
||
symbolS *symbol;
|
||
offsetT offset;
|
||
char *opcode;
|
||
{
|
||
register char *retval;
|
||
|
||
retval = obstack_next_free (&frchain_now->frch_obstack);
|
||
frag_now->fr_var = var;
|
||
frag_now->fr_type = type;
|
||
frag_now->fr_subtype = subtype;
|
||
frag_now->fr_symbol = symbol;
|
||
frag_now->fr_offset = offset;
|
||
frag_now->fr_opcode = opcode;
|
||
#ifdef USING_CGEN
|
||
frag_now->fr_cgen.insn = 0;
|
||
frag_now->fr_cgen.opindex = 0;
|
||
frag_now->fr_cgen.opinfo = 0;
|
||
#endif
|
||
#ifdef TC_FRAG_INIT
|
||
TC_FRAG_INIT (frag_now);
|
||
#endif
|
||
as_where (&frag_now->fr_file, &frag_now->fr_line);
|
||
frag_new (max_chars);
|
||
return (retval);
|
||
}
|
||
|
||
/* Reduce the variable end of a frag to a harmless state. */
|
||
|
||
void
|
||
frag_wane (fragP)
|
||
register fragS *fragP;
|
||
{
|
||
fragP->fr_type = rs_fill;
|
||
fragP->fr_offset = 0;
|
||
fragP->fr_var = 0;
|
||
}
|
||
|
||
/* Make an alignment frag. The size of this frag will be adjusted to
|
||
force the next frag to have the appropriate alignment. ALIGNMENT
|
||
is the power of two to which to align. FILL_CHARACTER is the
|
||
character to use to fill in any bytes which are skipped. MAX is
|
||
the maximum number of characters to skip when doing the alignment,
|
||
or 0 if there is no maximum. */
|
||
|
||
void
|
||
frag_align (alignment, fill_character, max)
|
||
int alignment;
|
||
int fill_character;
|
||
int max;
|
||
{
|
||
if (now_seg == absolute_section)
|
||
{
|
||
addressT new_off;
|
||
addressT mask;
|
||
|
||
mask = (~(addressT) 0) << alignment;
|
||
new_off = (abs_section_offset + ~mask) & mask;
|
||
if (max == 0 || new_off - abs_section_offset <= (addressT) max)
|
||
abs_section_offset = new_off;
|
||
}
|
||
else
|
||
{
|
||
char *p;
|
||
|
||
p = frag_var (rs_align, 1, 1, (relax_substateT) max,
|
||
(symbolS *) 0, (offsetT) alignment, (char *) 0);
|
||
*p = fill_character;
|
||
}
|
||
}
|
||
|
||
/* Make an alignment frag like frag_align, but fill with a repeating
|
||
pattern rather than a single byte. ALIGNMENT is the power of two
|
||
to which to align. FILL_PATTERN is the fill pattern to repeat in
|
||
the bytes which are skipped. N_FILL is the number of bytes in
|
||
FILL_PATTERN. MAX is the maximum number of characters to skip when
|
||
doing the alignment, or 0 if there is no maximum. */
|
||
|
||
void
|
||
frag_align_pattern (alignment, fill_pattern, n_fill, max)
|
||
int alignment;
|
||
const char *fill_pattern;
|
||
int n_fill;
|
||
int max;
|
||
{
|
||
char *p;
|
||
|
||
p = frag_var (rs_align, n_fill, n_fill, (relax_substateT) max,
|
||
(symbolS *) 0, (offsetT) alignment, (char *) 0);
|
||
memcpy (p, fill_pattern, n_fill);
|
||
}
|
||
|
||
/* The NOP_OPCODE is for the alignment fill value. Fill it with a nop
|
||
instruction so that the disassembler does not choke on it. */
|
||
#ifndef NOP_OPCODE
|
||
#define NOP_OPCODE 0x00
|
||
#endif
|
||
|
||
/* Use this to restrict the amount of memory allocated for representing
|
||
the alignment code. Needs to be large enough to hold any fixed sized
|
||
prologue plus the replicating portion. */
|
||
#ifndef MAX_MEM_FOR_RS_ALIGN_CODE
|
||
/* Assume that if HANDLE_ALIGN is not defined then no special action
|
||
is required to code fill, which means that we get just repeat the
|
||
one NOP_OPCODE byte. */
|
||
# ifndef HANDLE_ALIGN
|
||
# define MAX_MEM_FOR_RS_ALIGN_CODE 1
|
||
# else
|
||
# define MAX_MEM_FOR_RS_ALIGN_CODE ((1 << alignment) - 1)
|
||
# endif
|
||
#endif
|
||
|
||
void
|
||
frag_align_code (alignment, max)
|
||
int alignment;
|
||
int max;
|
||
{
|
||
char *p;
|
||
|
||
p = frag_var (rs_align_code, MAX_MEM_FOR_RS_ALIGN_CODE, 1,
|
||
(relax_substateT) max, (symbolS *) 0,
|
||
(offsetT) alignment, (char *) 0);
|
||
*p = NOP_OPCODE;
|
||
}
|
||
|
||
addressT
|
||
frag_now_fix_octets ()
|
||
{
|
||
if (now_seg == absolute_section)
|
||
return abs_section_offset;
|
||
|
||
return ((char *) obstack_next_free (&frchain_now->frch_obstack)
|
||
- frag_now->fr_literal);
|
||
}
|
||
|
||
addressT
|
||
frag_now_fix ()
|
||
{
|
||
return frag_now_fix_octets () / OCTETS_PER_BYTE;
|
||
}
|
||
|
||
void
|
||
frag_append_1_char (datum)
|
||
int datum;
|
||
{
|
||
if (obstack_room (&frchain_now->frch_obstack) <= 1)
|
||
{
|
||
frag_wane (frag_now);
|
||
frag_new (0);
|
||
}
|
||
obstack_1grow (&frchain_now->frch_obstack, datum);
|
||
}
|