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5222 | serge | 1 | /* subsegs.c - subsegments - |
6324 | serge | 2 | Copyright (C) 1987-2015 Free Software Foundation, Inc. |
5222 | serge | 3 | |
4 | This file is part of GAS, the GNU Assembler. |
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5 | |||
6 | GAS is free software; you can redistribute it and/or modify |
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7 | it under the terms of the GNU General Public License as published by |
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8 | the Free Software Foundation; either version 3, or (at your option) |
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9 | any later version. |
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10 | |||
11 | GAS is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | GNU General Public License for more details. |
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15 | |||
16 | You should have received a copy of the GNU General Public License |
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17 | along with GAS; see the file COPYING. If not, write to the Free |
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18 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
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19 | 02110-1301, USA. */ |
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20 | |||
21 | /* Segments & sub-segments. */ |
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22 | |||
23 | #include "as.h" |
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24 | |||
25 | #include "subsegs.h" |
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26 | #include "obstack.h" |
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27 | |||
28 | frchainS *frchain_now; |
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29 | |||
30 | static struct obstack frchains; |
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31 | |||
32 | static fragS dummy_frag; |
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33 | |||
34 | |||
35 | void |
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36 | subsegs_begin (void) |
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37 | { |
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38 | obstack_begin (&frchains, chunksize); |
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39 | #if __GNUC__ >= 2 |
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40 | obstack_alignment_mask (&frchains) = __alignof__ (frchainS) - 1; |
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41 | #endif |
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42 | |||
43 | frchain_now = NULL; /* Warn new_subseg() that we are booting. */ |
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44 | frag_now = &dummy_frag; |
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45 | } |
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46 | |||
47 | /* |
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48 | * subseg_change() |
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49 | * |
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50 | * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the |
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51 | * subsegment. If we are already in the correct subsegment, change nothing. |
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52 | * This is used eg as a worker for subseg_set [which does make a new frag_now] |
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53 | * and for changing segments after we have read the source. We construct eg |
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54 | * fixSs even after the source file is read, so we do have to keep the |
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55 | * segment context correct. |
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56 | */ |
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57 | void |
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6324 | serge | 58 | subseg_change (segT seg, int subseg) |
5222 | serge | 59 | { |
60 | segment_info_type *seginfo = seg_info (seg); |
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61 | now_seg = seg; |
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62 | now_subseg = subseg; |
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63 | |||
64 | if (! seginfo) |
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65 | { |
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66 | seginfo = (segment_info_type *) xcalloc (1, sizeof (*seginfo)); |
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67 | seginfo->bfd_section = seg; |
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68 | bfd_set_section_userdata (stdoutput, seg, seginfo); |
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69 | } |
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70 | } |
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71 | |||
72 | static void |
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73 | subseg_set_rest (segT seg, subsegT subseg) |
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74 | { |
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75 | frchainS *frcP; /* crawl frchain chain */ |
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76 | frchainS **lastPP; /* address of last pointer */ |
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77 | frchainS *newP; /* address of new frchain */ |
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78 | segment_info_type *seginfo; |
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79 | |||
80 | mri_common_symbol = NULL; |
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81 | |||
82 | if (frag_now && frchain_now) |
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83 | frchain_now->frch_frag_now = frag_now; |
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84 | |||
85 | gas_assert (frchain_now == 0 |
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86 | || frchain_now->frch_last == frag_now); |
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87 | |||
88 | subseg_change (seg, (int) subseg); |
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89 | |||
90 | seginfo = seg_info (seg); |
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91 | |||
92 | /* Attempt to find or make a frchain for that subsection. |
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93 | We keep the list sorted by subsection number. */ |
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94 | for (frcP = *(lastPP = &seginfo->frchainP); |
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95 | frcP != NULL; |
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96 | frcP = *(lastPP = &frcP->frch_next)) |
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97 | if (frcP->frch_subseg >= subseg) |
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98 | break; |
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99 | |||
100 | if (frcP == NULL || frcP->frch_subseg != subseg) |
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101 | { |
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102 | /* This should be the only code that creates a frchainS. */ |
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103 | |||
104 | newP = (frchainS *) obstack_alloc (&frchains, sizeof (frchainS)); |
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105 | newP->frch_subseg = subseg; |
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106 | newP->fix_root = NULL; |
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107 | newP->fix_tail = NULL; |
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108 | obstack_begin (&newP->frch_obstack, chunksize); |
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109 | #if __GNUC__ >= 2 |
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110 | obstack_alignment_mask (&newP->frch_obstack) = __alignof__ (fragS) - 1; |
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111 | #endif |
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112 | newP->frch_frag_now = frag_alloc (&newP->frch_obstack); |
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113 | newP->frch_frag_now->fr_type = rs_fill; |
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114 | newP->frch_cfi_data = NULL; |
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115 | |||
116 | newP->frch_root = newP->frch_last = newP->frch_frag_now; |
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117 | |||
118 | *lastPP = newP; |
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119 | newP->frch_next = frcP; |
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120 | frcP = newP; |
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121 | } |
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122 | |||
123 | frchain_now = frcP; |
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124 | frag_now = frcP->frch_frag_now; |
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125 | |||
126 | gas_assert (frchain_now->frch_last == frag_now); |
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127 | } |
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128 | |||
129 | /* |
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130 | * subseg_set(segT, subsegT) |
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131 | * |
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132 | * If you attempt to change to the current subsegment, nothing happens. |
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133 | * |
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134 | * In: segT, subsegT code for new subsegment. |
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135 | * frag_now -> incomplete frag for current subsegment. |
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136 | * If frag_now==NULL, then there is no old, incomplete frag, so |
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137 | * the old frag is not closed off. |
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138 | * |
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139 | * Out: now_subseg, now_seg updated. |
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140 | * Frchain_now points to the (possibly new) struct frchain for this |
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141 | * sub-segment. |
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142 | */ |
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143 | |||
144 | segT |
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145 | subseg_get (const char *segname, int force_new) |
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146 | { |
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147 | segT secptr; |
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148 | segment_info_type *seginfo; |
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149 | const char *now_seg_name = (now_seg |
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150 | ? bfd_get_section_name (stdoutput, now_seg) |
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151 | : 0); |
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152 | |||
153 | if (!force_new |
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154 | && now_seg_name |
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155 | && (now_seg_name == segname |
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156 | || !strcmp (now_seg_name, segname))) |
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157 | return now_seg; |
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158 | |||
159 | if (!force_new) |
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160 | secptr = bfd_make_section_old_way (stdoutput, segname); |
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161 | else |
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162 | secptr = bfd_make_section_anyway (stdoutput, segname); |
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163 | |||
164 | seginfo = seg_info (secptr); |
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165 | if (! seginfo) |
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166 | { |
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167 | secptr->output_section = secptr; |
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168 | seginfo = (segment_info_type *) xcalloc (1, sizeof (*seginfo)); |
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169 | seginfo->bfd_section = secptr; |
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170 | bfd_set_section_userdata (stdoutput, secptr, seginfo); |
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171 | } |
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172 | return secptr; |
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173 | } |
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174 | |||
175 | segT |
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176 | subseg_new (const char *segname, subsegT subseg) |
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177 | { |
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178 | segT secptr; |
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179 | |||
180 | secptr = subseg_get (segname, 0); |
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181 | subseg_set_rest (secptr, subseg); |
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182 | return secptr; |
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183 | } |
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184 | |||
185 | /* Like subseg_new, except a new section is always created, even if |
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186 | a section with that name already exists. */ |
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187 | segT |
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188 | subseg_force_new (const char *segname, subsegT subseg) |
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189 | { |
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190 | segT secptr; |
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191 | |||
192 | secptr = subseg_get (segname, 1); |
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193 | subseg_set_rest (secptr, subseg); |
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194 | return secptr; |
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195 | } |
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196 | |||
197 | void |
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198 | subseg_set (segT secptr, subsegT subseg) |
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199 | { |
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200 | if (! (secptr == now_seg && subseg == now_subseg)) |
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201 | subseg_set_rest (secptr, subseg); |
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202 | mri_common_symbol = NULL; |
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203 | } |
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204 | |||
205 | #ifndef obj_sec_sym_ok_for_reloc |
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206 | #define obj_sec_sym_ok_for_reloc(SEC) 0 |
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207 | #endif |
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208 | |||
209 | symbolS * |
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210 | section_symbol (segT sec) |
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211 | { |
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212 | segment_info_type *seginfo = seg_info (sec); |
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213 | symbolS *s; |
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214 | |||
215 | if (seginfo == 0) |
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216 | abort (); |
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217 | if (seginfo->sym) |
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218 | return seginfo->sym; |
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219 | |||
220 | #ifndef EMIT_SECTION_SYMBOLS |
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221 | #define EMIT_SECTION_SYMBOLS 1 |
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222 | #endif |
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223 | |||
224 | if (! EMIT_SECTION_SYMBOLS || symbol_table_frozen) |
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225 | { |
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226 | /* Here we know it won't be going into the symbol table. */ |
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227 | s = symbol_create (sec->symbol->name, sec, 0, &zero_address_frag); |
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228 | } |
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229 | else |
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230 | { |
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231 | segT seg; |
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232 | s = symbol_find (sec->symbol->name); |
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233 | /* We have to make sure it is the right symbol when we |
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234 | have multiple sections with the same section name. */ |
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235 | if (s == NULL |
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236 | || ((seg = S_GET_SEGMENT (s)) != sec |
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237 | && seg != undefined_section)) |
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238 | s = symbol_new (sec->symbol->name, sec, 0, &zero_address_frag); |
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239 | else if (seg == undefined_section) |
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240 | { |
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241 | S_SET_SEGMENT (s, sec); |
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242 | symbol_set_frag (s, &zero_address_frag); |
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243 | } |
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244 | } |
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245 | |||
246 | S_CLEAR_EXTERNAL (s); |
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247 | |||
248 | /* Use the BFD section symbol, if possible. */ |
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249 | if (obj_sec_sym_ok_for_reloc (sec)) |
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250 | symbol_set_bfdsym (s, sec->symbol); |
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251 | else |
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252 | symbol_get_bfdsym (s)->flags |= BSF_SECTION_SYM; |
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253 | |||
254 | seginfo->sym = s; |
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255 | return s; |
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256 | } |
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257 | |||
258 | /* Return whether the specified segment is thought to hold text. */ |
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259 | |||
260 | int |
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261 | subseg_text_p (segT sec) |
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262 | { |
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263 | return (bfd_get_section_flags (stdoutput, sec) & SEC_CODE) != 0; |
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264 | } |
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265 | |||
266 | /* Return non zero if SEC has at least one byte of data. It is |
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267 | possible that we'll return zero even on a non-empty section because |
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268 | we don't know all the fragment types, and it is possible that an |
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269 | fr_fix == 0 one still contributes data. Think of this as |
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270 | seg_definitely_not_empty_p. */ |
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271 | |||
272 | int |
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273 | seg_not_empty_p (segT sec ATTRIBUTE_UNUSED) |
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274 | { |
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275 | segment_info_type *seginfo = seg_info (sec); |
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276 | frchainS *chain; |
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277 | fragS *frag; |
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278 | |||
279 | if (!seginfo) |
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280 | return 0; |
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281 | |||
282 | for (chain = seginfo->frchainP; chain; chain = chain->frch_next) |
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283 | { |
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284 | for (frag = chain->frch_root; frag; frag = frag->fr_next) |
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285 | if (frag->fr_fix) |
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286 | return 1; |
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287 | if (obstack_next_free (&chain->frch_obstack) |
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288 | != chain->frch_last->fr_literal) |
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289 | return 1; |
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290 | } |
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291 | return 0; |
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292 | } |
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293 | |||
294 | void |
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295 | subsegs_print_statistics (FILE *file) |
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296 | { |
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297 | frchainS *frchp; |
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298 | asection *s; |
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299 | |||
300 | fprintf (file, "frag chains:\n"); |
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301 | for (s = stdoutput->sections; s; s = s->next) |
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302 | { |
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303 | segment_info_type *seginfo; |
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304 | |||
305 | /* Skip gas-internal sections. */ |
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306 | if (segment_name (s)[0] == '*') |
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307 | continue; |
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308 | |||
309 | seginfo = seg_info (s); |
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310 | if (!seginfo) |
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311 | continue; |
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312 | |||
313 | for (frchp = seginfo->frchainP; frchp; frchp = frchp->frch_next) |
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314 | { |
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315 | int count = 0; |
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316 | fragS *fragp; |
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317 | |||
318 | for (fragp = frchp->frch_root; fragp; fragp = fragp->fr_next) |
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319 | count++; |
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320 | |||
321 | fprintf (file, "\n"); |
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322 | fprintf (file, "\t%p %-10s\t%10d frags\n", (void *) frchp, |
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323 | segment_name (s), count); |
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324 | } |
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325 | } |
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326 | } |
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327 | |||
328 | /* end of subsegs.c */ |