1  /* subsegs.h -> subsegs.c
       2     Copyright (C) 1987-2023 Free Software Foundation, Inc.
       3  
       4     This file is part of GAS, the GNU Assembler.
       5  
       6     GAS is free software; you can redistribute it and/or modify
       7     it under the terms of the GNU General Public License as published by
       8     the Free Software Foundation; either version 3, or (at your option)
       9     any later version.
      10  
      11     GAS is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14     GNU General Public License for more details.
      15  
      16     You should have received a copy of the GNU General Public License
      17     along with GAS; see the file COPYING.  If not, write to the Free
      18     Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
      19     02110-1301, USA.  */
      20  
      21  /*
      22   * For every sub-segment the user mentions in the ASsembler program,
      23   * we make one struct frchain. Each sub-segment has exactly one struct frchain
      24   * and vice versa.
      25   *
      26   * Struct frchain's are forward chained (in ascending order of sub-segment
      27   * code number). The chain runs through frch_next of each subsegment.
      28   * This makes it hard to find a subsegment's frags
      29   * if programmer uses a lot of them. Most programs only use text0 and
      30   * data0, so they don't suffer. At least this way:
      31   * (1)	There are no "arbitrary" restrictions on how many subsegments
      32   *	can be programmed;
      33   * (2)	Subsegments' frchain-s are (later) chained together in the order in
      34   *	which they are emitted for object file viz text then data.
      35   *
      36   * From each struct frchain dangles a chain of struct frags. The frags
      37   * represent code fragments, for that sub-segment, forward chained.
      38   */
      39  
      40  #include "obstack.h"
      41  
      42  struct frch_cfi_data;
      43  
      44  struct frchain			/* control building of a frag chain */
      45  {				/* FRCH = FRagment CHain control */
      46    struct frag *frch_root;	/* 1st struct frag in chain, or NULL */
      47    struct frag *frch_last;	/* last struct frag in chain, or NULL */
      48    struct frchain *frch_next;	/* next in chain of struct frchain-s */
      49    subsegT frch_subseg;		/* subsegment number of this chain */
      50    fixS *fix_root;		/* Root of fixups for this subsegment.  */
      51    fixS *fix_tail;		/* Last fixup for this subsegment.  */
      52    struct obstack frch_obstack;	/* for objects in this frag chain */
      53    fragS *frch_frag_now;		/* frag_now for this subsegment */
      54    struct frch_cfi_data *frch_cfi_data;
      55  };
      56  
      57  typedef struct frchain frchainS;
      58  
      59  /* Frchain we are assembling into now.  That is, the current segment's
      60     frag chain, even if it contains no (complete) frags.  */
      61  extern frchainS *frchain_now;
      62  
      63  typedef struct segment_info_struct {
      64    frchainS *frchainP;
      65    unsigned int hadone : 1;
      66  
      67    /* This field is set if this is a .bss section which does not really
      68       have any contents.  Once upon a time a .bss section did not have
      69       any frags, but that is no longer true.  This field prevent the
      70       SEC_HAS_CONTENTS flag from being set for the section even if
      71       there are frags.  */
      72    unsigned int bss : 1;
      73  
      74    int user_stuff;
      75  
      76    /* Fixups for this segment.  This is only valid after the frchains
      77       are run together.  */
      78    fixS *fix_root;
      79    fixS *fix_tail;
      80  
      81    symbolS *dot;
      82  
      83    struct lineno_list *lineno_list_head;
      84    struct lineno_list *lineno_list_tail;
      85  
      86    /* Which BFD section does this gas segment correspond to?  */
      87    asection *bfd_section;
      88  
      89    /* NULL, or pointer to the gas symbol that is the section symbol for
      90       this section.  sym->bsym and bfd_section->symbol should be the same.  */
      91    symbolS *sym;
      92  
      93    /* Used by dwarf2dbg.c for this section's line table entries.  */
      94    void *dwarf2_line_seg;
      95  
      96    union {
      97      /* Current size of section holding stabs strings.  */
      98      unsigned long stab_string_size;
      99      /* Initial frag for ELF.  */
     100      char *p;
     101    }
     102    stabu;
     103  
     104  #ifdef NEED_LITERAL_POOL
     105    unsigned long literal_pool_size;
     106  #endif
     107  
     108  #ifdef TC_SEGMENT_INFO_TYPE
     109    TC_SEGMENT_INFO_TYPE tc_segment_info_data;
     110  #endif
     111  } segment_info_type;
     112  
     113  
     114  #define seg_info(sec) \
     115    ((segment_info_type *) bfd_section_userdata (sec))
     116  
     117  extern symbolS *section_symbol (segT);
     118  
     119  extern void subsegs_print_statistics (FILE *);