subsegs.h revision 77298
1/* subsegs.h -> subsegs.c 2 Copyright (C) 1987, 92, 93, 94, 95, 96, 98, 2000 3 Free Software Foundation, Inc. 4 5 This file is part of GAS, the GNU Assembler. 6 7 GAS is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2, or (at your option) 10 any later version. 11 12 GAS is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with GAS; see the file COPYING. If not, write to the Free 19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA 20 02111-1307, USA. */ 21 22/* 23 * For every sub-segment the user mentions in the ASsembler program, 24 * we make one struct frchain. Each sub-segment has exactly one struct frchain 25 * and vice versa. 26 * 27 * Struct frchain's are forward chained (in ascending order of sub-segment 28 * code number). The chain runs through frch_next of each subsegment. 29 * This makes it hard to find a subsegment's frags 30 * if programmer uses a lot of them. Most programs only use text0 and 31 * data0, so they don't suffer. At least this way: 32 * (1) There are no "arbitrary" restrictions on how many subsegments 33 * can be programmed; 34 * (2) Subsegments' frchain-s are (later) chained together in the order in 35 * which they are emitted for object file viz text then data. 36 * 37 * From each struct frchain dangles a chain of struct frags. The frags 38 * represent code fragments, for that sub-segment, forward chained. 39 */ 40 41#include "obstack.h" 42 43struct frchain /* control building of a frag chain */ 44{ /* FRCH = FRagment CHain control */ 45 struct frag *frch_root; /* 1st struct frag in chain, or NULL */ 46 struct frag *frch_last; /* last struct frag in chain, or NULL */ 47 struct frchain *frch_next; /* next in chain of struct frchain-s */ 48 segT frch_seg; /* SEG_TEXT or SEG_DATA. */ 49 subsegT frch_subseg; /* subsegment number of this chain */ 50#ifdef BFD_ASSEMBLER 51 fixS *fix_root; /* Root of fixups for this subsegment. */ 52 fixS *fix_tail; /* Last fixup for this subsegment. */ 53#endif 54 struct obstack frch_obstack; /* for objects in this frag chain */ 55 fragS *frch_frag_now; /* frag_now for this subsegment */ 56}; 57 58typedef struct frchain frchainS; 59 60/* All subsegments' chains hang off here. NULL means no frchains yet. */ 61extern frchainS *frchain_root; 62 63/* Frchain we are assembling into now. That is, the current segment's 64 frag chain, even if it contains no (complete) frags. */ 65extern frchainS *frchain_now; 66 67typedef struct segment_info_struct { 68 frchainS *frchainP; 69 unsigned int hadone : 1; 70 71 /* This field is set if this is a .bss section which does not really 72 have any contents. Once upon a time a .bss section did not have 73 any frags, but that is no longer true. This field prevent the 74 SEC_HAS_CONTENTS flag from being set for the section even if 75 there are frags. */ 76 unsigned int bss : 1; 77 78 int user_stuff; 79 80 /* Fixups for this segment. If BFD_ASSEMBLER, this is only valid 81 after the frchains are run together. */ 82 fixS *fix_root; 83 fixS *fix_tail; 84 85#if defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER) 86 struct internal_scnhdr scnhdr; 87 enum linkonce_type linkonce; 88 const char *name; 89#endif 90 91 symbolS *dot; 92 93 struct lineno_list *lineno_list_head; 94 struct lineno_list *lineno_list_tail; 95 96#ifdef BFD_ASSEMBLER 97 /* Which BFD section does this gas segment correspond to? */ 98 asection *bfd_section; 99 100 /* NULL, or pointer to the gas symbol that is the section symbol for 101 this section. sym->bsym and bfd_section->symbol should be the same. */ 102 symbolS *sym; 103#endif 104 105 union { 106 /* Current size of section holding stabs strings. */ 107 unsigned long stab_string_size; 108 /* Initial frag for ELF. */ 109 char *p; 110 } 111 stabu; 112 113#ifdef NEED_LITERAL_POOL 114 unsigned long literal_pool_size; 115#endif 116 117#ifdef TC_SEGMENT_INFO_TYPE 118 TC_SEGMENT_INFO_TYPE tc_segment_info_data; 119#endif 120} segment_info_type; 121 122#ifdef BFD_ASSEMBLER 123 124extern segment_info_type *seg_info PARAMS ((segT)); 125extern symbolS *section_symbol PARAMS ((segT)); 126 127#else /* ! BFD_ASSEMBLER */ 128 129#ifdef MANY_SEGMENTS 130 131extern segment_info_type segment_info[]; 132 133#define seg_info(SEC) (&segment_info[SEC]) 134 135#else 136 137/* Sentinel for frchain crawling. Points to the 1st data-segment 138 frchain. (Which is pointed to by the last text-segment frchain.) */ 139extern frchainS *data0_frchainP; 140extern frchainS *bss0_frchainP; 141 142/* Dummy so stuff can compile. Should never be used. */ 143struct seg_info_trash { 144 struct { 145 unsigned stab_string_size : 1; 146 } stabu; 147 unsigned hadone : 1; 148}; 149#define seg_info(S) (abort (), (struct seg_info_trash *) 0) 150 151#endif 152 153#endif /* ! BFD_ASSEMBLER */ 154 155extern void subsegs_print_statistics PARAMS ((FILE *)); 156