/* subsegs.h -> subsegs.c
  Copyright (C) 1987-2024 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.  */

/*
* 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.
*/

#include "obstack.h"

struct frch_cfi_data;
struct frch_ginsn_data;

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 */
 subsegT frch_subseg;          /* subsegment number of this chain */
 fixS *fix_root;               /* Root of fixups for this subsegment.  */
 fixS *fix_tail;               /* Last fixup for this subsegment.  */
 struct obstack frch_obstack;  /* for objects in this frag chain */
 fragS *frch_frag_now;         /* frag_now for this subsegment */
 struct frch_cfi_data *frch_cfi_data;
 struct frch_ginsn_data *frch_ginsn_data;
};

typedef struct frchain frchainS;

/* 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 segment_info_struct {
 frchainS *frchainP;
 unsigned 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.  */
 unsigned int bss : 1;

 /* Fixups for this segment.  This is only valid after the frchains
    are run together.  */
 fixS *fix_root;
 fixS *fix_tail;

 /* NULL, or pointer to the gas symbol that is the section symbol for
    this section.  */
 symbolS *sym;

 /* Used by dwarf2dbg.c for this section's line table entries.  */
 void *dwarf2_line_seg;

 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

#ifdef TC_SEGMENT_INFO_TYPE
 TC_SEGMENT_INFO_TYPE tc_segment_info_data;
#endif
} segment_info_type;


#define seg_info(sec) \
 ((segment_info_type *) bfd_section_userdata (sec))

extern symbolS *section_symbol (segT);

extern void subsegs_print_statistics (FILE *);