1 | /* subsegs.h -> subsegs.c |
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2 | Copyright 1987, 1992, 1993, 1994, 1995, 1996, 1998, 2000 |
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3 | Free Software Foundation, Inc. |
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4 | |
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5 | This file is part of GAS, the GNU Assembler. |
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6 | |
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7 | GAS is free software; you can redistribute it and/or modify |
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8 | it under the terms of the GNU General Public License as published by |
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9 | the Free Software Foundation; either version 2, or (at your option) |
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10 | any later version. |
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11 | |
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12 | GAS is distributed in the hope that it will be useful, |
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13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | GNU General Public License for more details. |
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16 | |
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17 | You should have received a copy of the GNU General Public License |
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18 | along with GAS; see the file COPYING. If not, write to the Free |
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19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
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20 | 02111-1307, USA. */ |
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21 | |
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22 | /* |
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23 | * For every sub-segment the user mentions in the ASsembler program, |
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24 | * we make one struct frchain. Each sub-segment has exactly one struct frchain |
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25 | * and vice versa. |
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26 | * |
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27 | * Struct frchain's are forward chained (in ascending order of sub-segment |
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28 | * code number). The chain runs through frch_next of each subsegment. |
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29 | * This makes it hard to find a subsegment's frags |
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30 | * if programmer uses a lot of them. Most programs only use text0 and |
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31 | * data0, so they don't suffer. At least this way: |
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32 | * (1) There are no "arbitrary" restrictions on how many subsegments |
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33 | * can be programmed; |
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34 | * (2) Subsegments' frchain-s are (later) chained together in the order in |
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35 | * which they are emitted for object file viz text then data. |
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36 | * |
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37 | * From each struct frchain dangles a chain of struct frags. The frags |
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38 | * represent code fragments, for that sub-segment, forward chained. |
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39 | */ |
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40 | |
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41 | #include "obstack.h" |
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42 | |
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43 | struct frchain /* control building of a frag chain */ |
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44 | { /* FRCH = FRagment CHain control */ |
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45 | struct frag *frch_root; /* 1st struct frag in chain, or NULL */ |
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46 | struct frag *frch_last; /* last struct frag in chain, or NULL */ |
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47 | struct frchain *frch_next; /* next in chain of struct frchain-s */ |
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48 | segT frch_seg; /* SEG_TEXT or SEG_DATA. */ |
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49 | subsegT frch_subseg; /* subsegment number of this chain */ |
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50 | #ifdef BFD_ASSEMBLER |
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51 | fixS *fix_root; /* Root of fixups for this subsegment. */ |
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52 | fixS *fix_tail; /* Last fixup for this subsegment. */ |
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53 | #endif |
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54 | struct obstack frch_obstack; /* for objects in this frag chain */ |
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55 | fragS *frch_frag_now; /* frag_now for this subsegment */ |
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56 | }; |
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57 | |
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58 | typedef struct frchain frchainS; |
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59 | |
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60 | /* All subsegments' chains hang off here. NULL means no frchains yet. */ |
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61 | extern frchainS *frchain_root; |
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62 | |
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63 | /* Frchain we are assembling into now. That is, the current segment's |
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64 | frag chain, even if it contains no (complete) frags. */ |
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65 | extern frchainS *frchain_now; |
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66 | |
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67 | typedef struct segment_info_struct { |
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68 | frchainS *frchainP; |
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69 | unsigned int hadone : 1; |
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70 | |
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71 | /* This field is set if this is a .bss section which does not really |
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72 | have any contents. Once upon a time a .bss section did not have |
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73 | any frags, but that is no longer true. This field prevent the |
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74 | SEC_HAS_CONTENTS flag from being set for the section even if |
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75 | there are frags. */ |
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76 | unsigned int bss : 1; |
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77 | |
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78 | int user_stuff; |
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79 | |
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80 | /* Fixups for this segment. If BFD_ASSEMBLER, this is only valid |
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81 | after the frchains are run together. */ |
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82 | fixS *fix_root; |
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83 | fixS *fix_tail; |
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84 | |
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85 | #if defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER) |
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86 | struct internal_scnhdr scnhdr; |
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87 | enum linkonce_type linkonce; |
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88 | const char *name; |
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89 | #endif |
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90 | |
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91 | symbolS *dot; |
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92 | |
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93 | struct lineno_list *lineno_list_head; |
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94 | struct lineno_list *lineno_list_tail; |
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95 | |
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96 | #ifdef BFD_ASSEMBLER |
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97 | /* Which BFD section does this gas segment correspond to? */ |
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98 | asection *bfd_section; |
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99 | |
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100 | /* NULL, or pointer to the gas symbol that is the section symbol for |
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101 | this section. sym->bsym and bfd_section->symbol should be the same. */ |
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102 | symbolS *sym; |
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103 | #endif |
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104 | |
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105 | union { |
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106 | /* Current size of section holding stabs strings. */ |
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107 | unsigned long stab_string_size; |
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108 | /* Initial frag for ELF. */ |
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109 | char *p; |
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110 | } |
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111 | stabu; |
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112 | |
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113 | #ifdef NEED_LITERAL_POOL |
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114 | unsigned long literal_pool_size; |
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115 | #endif |
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116 | |
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117 | #ifdef TC_SEGMENT_INFO_TYPE |
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118 | TC_SEGMENT_INFO_TYPE tc_segment_info_data; |
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119 | #endif |
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120 | } segment_info_type; |
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121 | |
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122 | #ifdef BFD_ASSEMBLER |
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123 | |
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124 | extern segment_info_type *seg_info PARAMS ((segT)); |
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125 | extern symbolS *section_symbol PARAMS ((segT)); |
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126 | |
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127 | #else /* ! BFD_ASSEMBLER */ |
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128 | |
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129 | #ifdef MANY_SEGMENTS |
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130 | |
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131 | extern segment_info_type segment_info[]; |
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132 | |
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133 | #define seg_info(SEC) (&segment_info[SEC]) |
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134 | |
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135 | #else |
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136 | |
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137 | /* Sentinel for frchain crawling. Points to the 1st data-segment |
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138 | frchain. (Which is pointed to by the last text-segment frchain.) */ |
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139 | extern frchainS *data0_frchainP; |
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140 | extern frchainS *bss0_frchainP; |
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141 | |
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142 | /* Dummy so stuff can compile. Should never be used. */ |
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143 | struct seg_info_trash { |
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144 | struct { |
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145 | unsigned stab_string_size : 1; |
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146 | } stabu; |
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147 | unsigned hadone : 1; |
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148 | }; |
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149 | #define seg_info(S) (abort (), (struct seg_info_trash *) 0) |
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150 | |
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151 | #endif |
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152 | |
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153 | #endif /* ! BFD_ASSEMBLER */ |
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154 | |
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155 | extern void subsegs_print_statistics PARAMS ((FILE *)); |
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