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/* subsegs.h -> subsegs.c
Copyright (C) 1987, 1992 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. */
/*
* For every sub-segment the user mentions in the ASsembler program,
* we make one struct frchain. Each sub-segment has exactly one struct frchain
* and vice versa.
*
* Struct frchain's are forward chained (in ascending order of sub-segment
* code number). The chain runs through frch_next of each subsegment.
* This makes it hard to find a subsegment's frags
* if programmer uses a lot of them. Most programs only use text0 and
* data0, so they don't suffer. At least this way:
* (1) There are no "arbitrary" restrictions on how many subsegments
* can be programmed;
* (2) Subsegments' frchain-s are (later) chained together in the order in
* which they are emitted for object file viz text then data.
*
* From each struct frchain dangles a chain of struct frags. The frags
* represent code fragments, for that sub-segment, forward chained.
*/
struct frchain /* control building of a frag chain */
{ /* FRCH = FRagment CHain control */
struct frag *frch_root; /* 1st struct frag in chain, or NULL */
struct frag *frch_last; /* last struct frag in chain, or NULL */
struct frchain *frch_next; /* next in chain of struct frchain-s */
segT frch_seg; /* SEG_TEXT or SEG_DATA. */
subsegT frch_subseg; /* subsegment number of this chain */
};
typedef struct frchain frchainS;
/* All subsegments' chains hang off here. NULL means no frchains yet. */
extern frchainS *frchain_root;
/* Frchain we are assembling into now That is, the current segment's
frag chain, even if it contains no (complete) frags. */
extern frchainS *frchain_now;
typedef struct
{
frchainS *frchainP;
int hadone : 1;
/* This field is set if this is a .bss section which does not really
have any contents. Once upon a time a .bss section did not have
any frags, but that is no longer true. This field prevent the
SEC_HAS_CONTENTS flag from being set for the section even if
there are frags. */
int bss : 1;
int user_stuff;
fixS *fix_root;
fixS *fix_tail;
#if defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
struct internal_scnhdr scnhdr;
#endif
symbolS *dot;
struct lineno_list *lineno_list_head;
struct lineno_list *lineno_list_tail;
#ifdef BFD_ASSEMBLER
/* Which BFD section does this gas segment correspond to? */
asection *bfd_section;
/* NULL, or pointer to the gas symbol that is the section symbol for
this section. sym->bsym and bfd_section->symbol should be the same. */
symbolS *sym;
#endif
union
{
/* Current size of section holding stabs strings. */
unsigned long stab_string_size;
/* Initial frag for ELF. */
char *p;
}
stabu;
#ifdef NEED_LITERAL_POOL
unsigned long literal_pool_size;
#endif
} segment_info_type;
#ifdef BFD_ASSEMBLER
#define seg_info(SEC) \
((segment_info_type *) bfd_get_section_userdata (stdoutput, (SEC)))
extern symbolS *section_symbol PARAMS ((segT));
#else /* ! BFD_ASSEMBLER */
#ifdef MANY_SEGMENTS
extern segment_info_type segment_info[];
#define seg_info(SEC) (&segment_info[SEC])
#else
/* Sentinel for frchain crawling. Points to the 1st data-segment
frchain. (Which is pointed to by the last text-segment frchain.) */
extern frchainS *data0_frchainP;
extern frchainS *bss0_frchainP;
#endif
#endif /* ! BFD_ASSEMBLER */
/* end of subsegs.h */
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