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5199 | serge | 1 | /* ldctor.c -- constructor support routines |
6324 | serge | 2 | Copyright (C) 1991-2015 Free Software Foundation, Inc. |
5199 | serge | 3 | By Steve Chamberlain |
4 | |||
5 | This file is part of the GNU Binutils. |
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6 | |||
7 | This program 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 3 of the License, or |
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10 | (at your option) any later version. |
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11 | |||
12 | This program 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 | |||
17 | You should have received a copy of the GNU General Public License |
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18 | along with this program; if not, write to the Free Software |
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19 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
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20 | MA 02110-1301, USA. */ |
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21 | |||
22 | #include "sysdep.h" |
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23 | #include "bfd.h" |
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24 | #include "bfdlink.h" |
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25 | #include "safe-ctype.h" |
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26 | |||
27 | #include "ld.h" |
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28 | #include "ldexp.h" |
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29 | #include "ldlang.h" |
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30 | #include "ldmisc.h" |
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31 | #include |
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32 | #include "ldmain.h" |
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33 | #include "ldctor.h" |
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34 | |||
35 | /* The list of statements needed to handle constructors. These are |
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36 | invoked by the command CONSTRUCTORS in the linker script. */ |
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37 | lang_statement_list_type constructor_list; |
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38 | |||
39 | /* Whether the constructors should be sorted. Note that this is |
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40 | global for the entire link; we assume that there is only a single |
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41 | CONSTRUCTORS command in the linker script. */ |
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42 | bfd_boolean constructors_sorted; |
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43 | |||
44 | /* The sets we have seen. */ |
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45 | struct set_info *sets; |
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46 | |||
47 | /* Add an entry to a set. H is the entry in the linker hash table. |
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48 | RELOC is the relocation to use for an entry in the set. SECTION |
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49 | and VALUE are the value to add. This is called during the first |
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50 | phase of the link, when we are still gathering symbols together. |
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51 | We just record the information now. The ldctor_build_sets |
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52 | function will construct the sets. */ |
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53 | |||
54 | void |
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55 | ldctor_add_set_entry (struct bfd_link_hash_entry *h, |
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56 | bfd_reloc_code_real_type reloc, |
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57 | const char *name, |
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58 | asection *section, |
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59 | bfd_vma value) |
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60 | { |
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61 | struct set_info *p; |
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62 | struct set_element *e; |
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63 | struct set_element **epp; |
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64 | |||
65 | for (p = sets; p != NULL; p = p->next) |
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66 | if (p->h == h) |
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67 | break; |
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68 | |||
69 | if (p == NULL) |
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70 | { |
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71 | p = (struct set_info *) xmalloc (sizeof (struct set_info)); |
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72 | p->next = sets; |
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73 | sets = p; |
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74 | p->h = h; |
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75 | p->reloc = reloc; |
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76 | p->count = 0; |
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77 | p->elements = NULL; |
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78 | } |
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79 | else |
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80 | { |
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81 | if (p->reloc != reloc) |
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82 | { |
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83 | einfo (_("%P%X: Different relocs used in set %s\n"), |
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84 | h->root.string); |
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85 | return; |
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86 | } |
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87 | |||
88 | /* Don't permit a set to be constructed from different object |
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89 | file formats. The same reloc may have different results. We |
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90 | actually could sometimes handle this, but the case is |
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91 | unlikely to ever arise. Sometimes constructor symbols are in |
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92 | unusual sections, such as the absolute section--this appears |
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93 | to be the case in Linux a.out--and in such cases we just |
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94 | assume everything is OK. */ |
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95 | if (p->elements != NULL |
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96 | && section->owner != NULL |
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97 | && p->elements->section->owner != NULL |
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98 | && strcmp (bfd_get_target (section->owner), |
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99 | bfd_get_target (p->elements->section->owner)) != 0) |
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100 | { |
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101 | einfo (_("%P%X: Different object file formats composing set %s\n"), |
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102 | h->root.string); |
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103 | return; |
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104 | } |
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105 | } |
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106 | |||
107 | e = (struct set_element *) xmalloc (sizeof (struct set_element)); |
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108 | e->next = NULL; |
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109 | e->name = name; |
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110 | e->section = section; |
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111 | e->value = value; |
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112 | |||
113 | for (epp = &p->elements; *epp != NULL; epp = &(*epp)->next) |
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114 | ; |
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115 | *epp = e; |
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116 | |||
117 | ++p->count; |
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118 | } |
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119 | |||
120 | /* Get the priority of a g++ global constructor or destructor from the |
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121 | symbol name. */ |
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122 | |||
123 | static int |
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124 | ctor_prio (const char *name) |
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125 | { |
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126 | /* The name will look something like _GLOBAL_$I$65535$test02__Fv. |
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127 | There might be extra leading underscores, and the $ characters |
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128 | might be something else. The I might be a D. */ |
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129 | |||
130 | while (*name == '_') |
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131 | ++name; |
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132 | |||
133 | if (! CONST_STRNEQ (name, "GLOBAL_")) |
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134 | return -1; |
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135 | |||
136 | name += sizeof "GLOBAL_" - 1; |
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137 | |||
138 | if (name[0] != name[2]) |
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139 | return -1; |
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140 | if (name[1] != 'I' && name[1] != 'D') |
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141 | return -1; |
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142 | if (! ISDIGIT (name[3])) |
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143 | return -1; |
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144 | |||
145 | return atoi (name + 3); |
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146 | } |
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147 | |||
148 | /* This function is used to sort constructor elements by priority. It |
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149 | is called via qsort. */ |
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150 | |||
151 | static int |
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152 | ctor_cmp (const void *p1, const void *p2) |
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153 | { |
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154 | const struct set_element * const *pe1 = |
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155 | (const struct set_element * const *) p1; |
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156 | const struct set_element * const *pe2 = |
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157 | (const struct set_element * const *) p2; |
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158 | const char *n1; |
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159 | const char *n2; |
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160 | int prio1; |
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161 | int prio2; |
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162 | |||
163 | n1 = (*pe1)->name; |
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164 | if (n1 == NULL) |
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165 | n1 = ""; |
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166 | n2 = (*pe2)->name; |
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167 | if (n2 == NULL) |
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168 | n2 = ""; |
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169 | |||
170 | /* We need to sort in reverse order by priority. When two |
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171 | constructors have the same priority, we should maintain their |
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172 | current relative position. */ |
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173 | |||
174 | prio1 = ctor_prio (n1); |
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175 | prio2 = ctor_prio (n2); |
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176 | |||
177 | /* We sort in reverse order because that is what g++ expects. */ |
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178 | if (prio1 < prio2) |
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179 | return 1; |
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180 | else if (prio1 > prio2) |
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181 | return -1; |
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182 | |||
183 | /* Force a stable sort. */ |
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184 | |||
185 | if (pe1 < pe2) |
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186 | return -1; |
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187 | else if (pe1 > pe2) |
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188 | return 1; |
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189 | else |
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190 | return 0; |
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191 | } |
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192 | |||
193 | /* This function is called after the first phase of the link and |
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194 | before the second phase. At this point all set information has |
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195 | been gathered. We now put the statements to build the sets |
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196 | themselves into constructor_list. */ |
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197 | |||
198 | void |
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199 | ldctor_build_sets (void) |
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200 | { |
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201 | static bfd_boolean called; |
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202 | bfd_boolean header_printed; |
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203 | struct set_info *p; |
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204 | |||
205 | /* The emulation code may call us directly, but we only want to do |
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206 | this once. */ |
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207 | if (called) |
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208 | return; |
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209 | called = TRUE; |
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210 | |||
211 | if (constructors_sorted) |
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212 | { |
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213 | for (p = sets; p != NULL; p = p->next) |
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214 | { |
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215 | int c, i; |
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216 | struct set_element *e; |
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217 | struct set_element **array; |
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218 | |||
219 | if (p->elements == NULL) |
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220 | continue; |
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221 | |||
222 | c = 0; |
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223 | for (e = p->elements; e != NULL; e = e->next) |
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224 | ++c; |
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225 | |||
226 | array = (struct set_element **) xmalloc (c * sizeof *array); |
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227 | |||
228 | i = 0; |
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229 | for (e = p->elements; e != NULL; e = e->next) |
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230 | { |
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231 | array[i] = e; |
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232 | ++i; |
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233 | } |
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234 | |||
235 | qsort (array, c, sizeof *array, ctor_cmp); |
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236 | |||
237 | e = array[0]; |
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238 | p->elements = e; |
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239 | for (i = 0; i < c - 1; i++) |
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240 | array[i]->next = array[i + 1]; |
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241 | array[i]->next = NULL; |
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242 | |||
243 | free (array); |
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244 | } |
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245 | } |
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246 | |||
247 | lang_list_init (&constructor_list); |
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248 | push_stat_ptr (&constructor_list); |
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249 | |||
250 | header_printed = FALSE; |
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251 | for (p = sets; p != NULL; p = p->next) |
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252 | { |
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253 | struct set_element *e; |
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254 | reloc_howto_type *howto; |
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255 | int reloc_size, size; |
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256 | |||
257 | /* If the symbol is defined, we may have been invoked from |
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258 | collect, and the sets may already have been built, so we do |
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259 | not do anything. */ |
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260 | if (p->h->type == bfd_link_hash_defined |
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261 | || p->h->type == bfd_link_hash_defweak) |
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262 | continue; |
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263 | |||
264 | /* For each set we build: |
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265 | set: |
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266 | .long number_of_elements |
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267 | .long element0 |
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268 | ... |
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269 | .long elementN |
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270 | .long 0 |
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271 | except that we use the right size instead of .long. When |
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272 | generating relocatable output, we generate relocs instead of |
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273 | addresses. */ |
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274 | howto = bfd_reloc_type_lookup (link_info.output_bfd, p->reloc); |
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275 | if (howto == NULL) |
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276 | { |
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6324 | serge | 277 | if (bfd_link_relocatable (&link_info)) |
5199 | serge | 278 | { |
279 | einfo (_("%P%X: %s does not support reloc %s for set %s\n"), |
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280 | bfd_get_target (link_info.output_bfd), |
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281 | bfd_get_reloc_code_name (p->reloc), |
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282 | p->h->root.string); |
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283 | continue; |
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284 | } |
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285 | |||
286 | /* If this is not a relocatable link, all we need is the |
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287 | size, which we can get from the input BFD. */ |
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288 | if (p->elements->section->owner != NULL) |
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289 | howto = bfd_reloc_type_lookup (p->elements->section->owner, |
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290 | p->reloc); |
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291 | if (howto == NULL) |
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292 | { |
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293 | einfo (_("%P%X: %s does not support reloc %s for set %s\n"), |
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294 | bfd_get_target (p->elements->section->owner), |
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295 | bfd_get_reloc_code_name (p->reloc), |
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296 | p->h->root.string); |
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297 | continue; |
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298 | } |
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299 | } |
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300 | |||
301 | reloc_size = bfd_get_reloc_size (howto); |
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302 | switch (reloc_size) |
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303 | { |
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304 | case 1: size = BYTE; break; |
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305 | case 2: size = SHORT; break; |
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306 | case 4: size = LONG; break; |
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307 | case 8: |
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308 | if (howto->complain_on_overflow == complain_overflow_signed) |
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309 | size = SQUAD; |
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310 | else |
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311 | size = QUAD; |
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312 | break; |
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313 | default: |
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314 | einfo (_("%P%X: Unsupported size %d for set %s\n"), |
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315 | bfd_get_reloc_size (howto), p->h->root.string); |
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316 | size = LONG; |
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317 | break; |
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318 | } |
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319 | |||
320 | lang_add_assignment (exp_assign (".", |
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321 | exp_unop (ALIGN_K, |
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322 | exp_intop (reloc_size)), |
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323 | FALSE)); |
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324 | lang_add_assignment (exp_assign (p->h->root.string, |
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325 | exp_nameop (NAME, "."), |
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326 | FALSE)); |
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327 | lang_add_data (size, exp_intop (p->count)); |
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328 | |||
329 | for (e = p->elements; e != NULL; e = e->next) |
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330 | { |
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331 | if (config.map_file != NULL) |
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332 | { |
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333 | int len; |
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334 | |||
335 | if (! header_printed) |
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336 | { |
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337 | minfo (_("\nSet Symbol\n\n")); |
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338 | header_printed = TRUE; |
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339 | } |
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340 | |||
341 | minfo ("%s", p->h->root.string); |
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342 | len = strlen (p->h->root.string); |
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343 | |||
344 | if (len >= 19) |
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345 | { |
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346 | print_nl (); |
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347 | len = 0; |
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348 | } |
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349 | while (len < 20) |
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350 | { |
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351 | print_space (); |
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352 | ++len; |
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353 | } |
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354 | |||
355 | if (e->name != NULL) |
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356 | minfo ("%T\n", e->name); |
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357 | else |
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358 | minfo ("%G\n", e->section->owner, e->section, e->value); |
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359 | } |
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360 | |||
361 | /* Need SEC_KEEP for --gc-sections. */ |
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362 | if (! bfd_is_abs_section (e->section)) |
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363 | e->section->flags |= SEC_KEEP; |
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364 | |||
6324 | serge | 365 | if (bfd_link_relocatable (&link_info)) |
5199 | serge | 366 | lang_add_reloc (p->reloc, howto, e->section, e->name, |
367 | exp_intop (e->value)); |
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368 | else |
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369 | lang_add_data (size, exp_relop (e->section, e->value)); |
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370 | } |
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371 | |||
372 | lang_add_data (size, exp_intop (0)); |
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373 | } |
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374 | |||
375 | pop_stat_ptr (); |
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376 | }>>>> |