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0
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1 /* Subroutines needed for unwinding stack frames for exception handling. */
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2 /* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2008,
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3 2009 Free Software Foundation, Inc.
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4 Contributed by Jason Merrill <jason@cygnus.com>.
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5
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6 This file is part of GCC.
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7
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8 GCC is free software; you can redistribute it and/or modify it under
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9 the terms of the GNU General Public License as published by the Free
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10 Software Foundation; either version 3, or (at your option) any later
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11 version.
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12
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13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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16 for more details.
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17
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18 Under Section 7 of GPL version 3, you are granted additional
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19 permissions described in the GCC Runtime Library Exception, version
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20 3.1, as published by the Free Software Foundation.
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21
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22 You should have received a copy of the GNU General Public License and
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23 a copy of the GCC Runtime Library Exception along with this program;
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24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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25 <http://www.gnu.org/licenses/>. */
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26
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27 #ifndef _Unwind_Find_FDE
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28 #include "tconfig.h"
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29 #include "tsystem.h"
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30 #include "coretypes.h"
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31 #include "tm.h"
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32 #include "dwarf2.h"
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33 #include "unwind.h"
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34 #define NO_BASE_OF_ENCODED_VALUE
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35 #include "unwind-pe.h"
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36 #include "unwind-dw2-fde.h"
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37 #include "gthr.h"
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38 #endif
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39
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40 /* The unseen_objects list contains objects that have been registered
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41 but not yet categorized in any way. The seen_objects list has had
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42 its pc_begin and count fields initialized at minimum, and is sorted
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43 by decreasing value of pc_begin. */
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44 static struct object *unseen_objects;
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45 static struct object *seen_objects;
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46
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47 #ifdef __GTHREAD_MUTEX_INIT
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48 static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
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49 #else
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50 static __gthread_mutex_t object_mutex;
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51 #endif
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52
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53 #ifdef __GTHREAD_MUTEX_INIT_FUNCTION
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54 static void
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55 init_object_mutex (void)
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56 {
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57 __GTHREAD_MUTEX_INIT_FUNCTION (&object_mutex);
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58 }
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59
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60 static void
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61 init_object_mutex_once (void)
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62 {
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63 static __gthread_once_t once = __GTHREAD_ONCE_INIT;
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64 __gthread_once (&once, init_object_mutex);
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65 }
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66 #else
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67 #define init_object_mutex_once()
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68 #endif
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69
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70 /* Called from crtbegin.o to register the unwind info for an object. */
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71
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72 void
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73 __register_frame_info_bases (const void *begin, struct object *ob,
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74 void *tbase, void *dbase)
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75 {
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76 /* If .eh_frame is empty, don't register at all. */
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77 if ((const uword *) begin == 0 || *(const uword *) begin == 0)
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78 return;
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79
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80 ob->pc_begin = (void *)-1;
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81 ob->tbase = tbase;
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82 ob->dbase = dbase;
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83 ob->u.single = begin;
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84 ob->s.i = 0;
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85 ob->s.b.encoding = DW_EH_PE_omit;
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86 #ifdef DWARF2_OBJECT_END_PTR_EXTENSION
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87 ob->fde_end = NULL;
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88 #endif
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89
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90 init_object_mutex_once ();
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91 __gthread_mutex_lock (&object_mutex);
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92
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93 ob->next = unseen_objects;
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94 unseen_objects = ob;
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95
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96 __gthread_mutex_unlock (&object_mutex);
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97 }
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98
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99 void
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100 __register_frame_info (const void *begin, struct object *ob)
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101 {
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102 __register_frame_info_bases (begin, ob, 0, 0);
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103 }
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104
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105 void
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106 __register_frame (void *begin)
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107 {
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108 struct object *ob;
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109
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110 /* If .eh_frame is empty, don't register at all. */
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111 if (*(uword *) begin == 0)
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112 return;
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113
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114 ob = malloc (sizeof (struct object));
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115 __register_frame_info (begin, ob);
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116 }
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117
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118 /* Similar, but BEGIN is actually a pointer to a table of unwind entries
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119 for different translation units. Called from the file generated by
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120 collect2. */
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121
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122 void
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123 __register_frame_info_table_bases (void *begin, struct object *ob,
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124 void *tbase, void *dbase)
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125 {
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126 ob->pc_begin = (void *)-1;
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127 ob->tbase = tbase;
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128 ob->dbase = dbase;
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129 ob->u.array = begin;
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130 ob->s.i = 0;
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131 ob->s.b.from_array = 1;
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132 ob->s.b.encoding = DW_EH_PE_omit;
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133
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134 init_object_mutex_once ();
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135 __gthread_mutex_lock (&object_mutex);
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136
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137 ob->next = unseen_objects;
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138 unseen_objects = ob;
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139
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140 __gthread_mutex_unlock (&object_mutex);
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141 }
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142
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143 void
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144 __register_frame_info_table (void *begin, struct object *ob)
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145 {
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146 __register_frame_info_table_bases (begin, ob, 0, 0);
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147 }
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148
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149 void
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150 __register_frame_table (void *begin)
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151 {
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152 struct object *ob = malloc (sizeof (struct object));
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153 __register_frame_info_table (begin, ob);
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154 }
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155
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156 /* Called from crtbegin.o to deregister the unwind info for an object. */
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157 /* ??? Glibc has for a while now exported __register_frame_info and
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158 __deregister_frame_info. If we call __register_frame_info_bases
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159 from crtbegin (wherein it is declared weak), and this object does
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160 not get pulled from libgcc.a for other reasons, then the
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161 invocation of __deregister_frame_info will be resolved from glibc.
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162 Since the registration did not happen there, we'll die.
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163
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164 Therefore, declare a new deregistration entry point that does the
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165 exact same thing, but will resolve to the same library as
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166 implements __register_frame_info_bases. */
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167
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168 void *
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169 __deregister_frame_info_bases (const void *begin)
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170 {
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171 struct object **p;
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172 struct object *ob = 0;
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173
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174 /* If .eh_frame is empty, we haven't registered. */
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175 if ((const uword *) begin == 0 || *(const uword *) begin == 0)
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176 return ob;
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177
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178 init_object_mutex_once ();
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179 __gthread_mutex_lock (&object_mutex);
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180
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181 for (p = &unseen_objects; *p ; p = &(*p)->next)
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182 if ((*p)->u.single == begin)
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183 {
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184 ob = *p;
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185 *p = ob->next;
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186 goto out;
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187 }
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188
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189 for (p = &seen_objects; *p ; p = &(*p)->next)
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190 if ((*p)->s.b.sorted)
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191 {
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192 if ((*p)->u.sort->orig_data == begin)
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193 {
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194 ob = *p;
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195 *p = ob->next;
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196 free (ob->u.sort);
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197 goto out;
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198 }
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199 }
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200 else
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201 {
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202 if ((*p)->u.single == begin)
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203 {
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204 ob = *p;
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205 *p = ob->next;
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206 goto out;
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207 }
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208 }
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209
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210 out:
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211 __gthread_mutex_unlock (&object_mutex);
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212 gcc_assert (ob);
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213 return (void *) ob;
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214 }
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215
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216 void *
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217 __deregister_frame_info (const void *begin)
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218 {
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219 return __deregister_frame_info_bases (begin);
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220 }
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221
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222 void
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223 __deregister_frame (void *begin)
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224 {
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225 /* If .eh_frame is empty, we haven't registered. */
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226 if (*(uword *) begin != 0)
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227 free (__deregister_frame_info (begin));
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228 }
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229
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230
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231 /* Like base_of_encoded_value, but take the base from a struct object
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232 instead of an _Unwind_Context. */
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233
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234 static _Unwind_Ptr
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235 base_from_object (unsigned char encoding, struct object *ob)
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236 {
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237 if (encoding == DW_EH_PE_omit)
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238 return 0;
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239
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240 switch (encoding & 0x70)
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241 {
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242 case DW_EH_PE_absptr:
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243 case DW_EH_PE_pcrel:
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244 case DW_EH_PE_aligned:
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245 return 0;
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246
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247 case DW_EH_PE_textrel:
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248 return (_Unwind_Ptr) ob->tbase;
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249 case DW_EH_PE_datarel:
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250 return (_Unwind_Ptr) ob->dbase;
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251 default:
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252 gcc_unreachable ();
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253 }
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254 }
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255
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256 /* Return the FDE pointer encoding from the CIE. */
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257 /* ??? This is a subset of extract_cie_info from unwind-dw2.c. */
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258
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259 static int
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260 get_cie_encoding (const struct dwarf_cie *cie)
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261 {
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262 const unsigned char *aug, *p;
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263 _Unwind_Ptr dummy;
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264 _uleb128_t utmp;
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265 _sleb128_t stmp;
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266
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267 aug = cie->augmentation;
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268 if (aug[0] != 'z')
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269 return DW_EH_PE_absptr;
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270
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271 p = aug + strlen ((const char *)aug) + 1; /* Skip the augmentation string. */
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272 p = read_uleb128 (p, &utmp); /* Skip code alignment. */
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273 p = read_sleb128 (p, &stmp); /* Skip data alignment. */
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274 if (cie->version == 1) /* Skip return address column. */
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275 p++;
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276 else
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277 p = read_uleb128 (p, &utmp);
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278
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279 aug++; /* Skip 'z' */
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280 p = read_uleb128 (p, &utmp); /* Skip augmentation length. */
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281 while (1)
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282 {
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283 /* This is what we're looking for. */
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284 if (*aug == 'R')
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285 return *p;
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286 /* Personality encoding and pointer. */
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287 else if (*aug == 'P')
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288 {
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289 /* ??? Avoid dereferencing indirect pointers, since we're
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290 faking the base address. Gotta keep DW_EH_PE_aligned
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291 intact, however. */
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292 p = read_encoded_value_with_base (*p & 0x7F, 0, p + 1, &dummy);
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293 }
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294 /* LSDA encoding. */
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295 else if (*aug == 'L')
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296 p++;
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297 /* Otherwise end of string, or unknown augmentation. */
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298 else
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299 return DW_EH_PE_absptr;
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300 aug++;
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301 }
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302 }
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303
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304 static inline int
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305 get_fde_encoding (const struct dwarf_fde *f)
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306 {
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307 return get_cie_encoding (get_cie (f));
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308 }
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309
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310
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311 /* Sorting an array of FDEs by address.
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312 (Ideally we would have the linker sort the FDEs so we don't have to do
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313 it at run time. But the linkers are not yet prepared for this.) */
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314
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315 /* Comparison routines. Three variants of increasing complexity. */
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316
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317 static int
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318 fde_unencoded_compare (struct object *ob __attribute__((unused)),
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319 const fde *x, const fde *y)
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320 {
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321 const _Unwind_Ptr x_ptr = *(const _Unwind_Ptr *) x->pc_begin;
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322 const _Unwind_Ptr y_ptr = *(const _Unwind_Ptr *) y->pc_begin;
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323
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324 if (x_ptr > y_ptr)
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325 return 1;
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326 if (x_ptr < y_ptr)
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327 return -1;
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328 return 0;
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329 }
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330
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331 static int
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332 fde_single_encoding_compare (struct object *ob, const fde *x, const fde *y)
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333 {
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334 _Unwind_Ptr base, x_ptr, y_ptr;
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335
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336 base = base_from_object (ob->s.b.encoding, ob);
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337 read_encoded_value_with_base (ob->s.b.encoding, base, x->pc_begin, &x_ptr);
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338 read_encoded_value_with_base (ob->s.b.encoding, base, y->pc_begin, &y_ptr);
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339
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340 if (x_ptr > y_ptr)
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341 return 1;
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342 if (x_ptr < y_ptr)
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343 return -1;
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344 return 0;
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345 }
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346
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347 static int
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348 fde_mixed_encoding_compare (struct object *ob, const fde *x, const fde *y)
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349 {
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350 int x_encoding, y_encoding;
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351 _Unwind_Ptr x_ptr, y_ptr;
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352
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353 x_encoding = get_fde_encoding (x);
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354 read_encoded_value_with_base (x_encoding, base_from_object (x_encoding, ob),
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355 x->pc_begin, &x_ptr);
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356
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357 y_encoding = get_fde_encoding (y);
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358 read_encoded_value_with_base (y_encoding, base_from_object (y_encoding, ob),
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359 y->pc_begin, &y_ptr);
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360
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361 if (x_ptr > y_ptr)
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362 return 1;
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363 if (x_ptr < y_ptr)
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364 return -1;
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365 return 0;
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366 }
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367
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368 typedef int (*fde_compare_t) (struct object *, const fde *, const fde *);
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369
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370
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371 /* This is a special mix of insertion sort and heap sort, optimized for
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372 the data sets that actually occur. They look like
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373 101 102 103 127 128 105 108 110 190 111 115 119 125 160 126 129 130.
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374 I.e. a linearly increasing sequence (coming from functions in the text
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375 section), with additionally a few unordered elements (coming from functions
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376 in gnu_linkonce sections) whose values are higher than the values in the
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377 surrounding linear sequence (but not necessarily higher than the values
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378 at the end of the linear sequence!).
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379 The worst-case total run time is O(N) + O(n log (n)), where N is the
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380 total number of FDEs and n is the number of erratic ones. */
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381
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382 struct fde_accumulator
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383 {
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384 struct fde_vector *linear;
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385 struct fde_vector *erratic;
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386 };
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387
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388 static inline int
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389 start_fde_sort (struct fde_accumulator *accu, size_t count)
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390 {
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391 size_t size;
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392 if (! count)
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393 return 0;
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394
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395 size = sizeof (struct fde_vector) + sizeof (const fde *) * count;
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396 if ((accu->linear = malloc (size)))
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397 {
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398 accu->linear->count = 0;
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399 if ((accu->erratic = malloc (size)))
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400 accu->erratic->count = 0;
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401 return 1;
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402 }
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403 else
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404 return 0;
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405 }
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406
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407 static inline void
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408 fde_insert (struct fde_accumulator *accu, const fde *this_fde)
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409 {
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410 if (accu->linear)
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411 accu->linear->array[accu->linear->count++] = this_fde;
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412 }
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413
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414 /* Split LINEAR into a linear sequence with low values and an erratic
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415 sequence with high values, put the linear one (of longest possible
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416 length) into LINEAR and the erratic one into ERRATIC. This is O(N).
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417
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|
418 Because the longest linear sequence we are trying to locate within the
|
|
|
419 incoming LINEAR array can be interspersed with (high valued) erratic
|
|
|
420 entries. We construct a chain indicating the sequenced entries.
|
|
|
421 To avoid having to allocate this chain, we overlay it onto the space of
|
|
|
422 the ERRATIC array during construction. A final pass iterates over the
|
|
|
423 chain to determine what should be placed in the ERRATIC array, and
|
|
|
424 what is the linear sequence. This overlay is safe from aliasing. */
|
|
|
425
|
|
|
426 static inline void
|
|
|
427 fde_split (struct object *ob, fde_compare_t fde_compare,
|
|
|
428 struct fde_vector *linear, struct fde_vector *erratic)
|
|
|
429 {
|
|
|
430 static const fde *marker;
|
|
|
431 size_t count = linear->count;
|
|
|
432 const fde *const *chain_end = ▮
|
|
|
433 size_t i, j, k;
|
|
|
434
|
|
|
435 /* This should optimize out, but it is wise to make sure this assumption
|
|
|
436 is correct. Should these have different sizes, we cannot cast between
|
|
|
437 them and the overlaying onto ERRATIC will not work. */
|
|
|
438 gcc_assert (sizeof (const fde *) == sizeof (const fde **));
|
|
|
439
|
|
|
440 for (i = 0; i < count; i++)
|
|
|
441 {
|
|
|
442 const fde *const *probe;
|
|
|
443
|
|
|
444 for (probe = chain_end;
|
|
|
445 probe != &marker && fde_compare (ob, linear->array[i], *probe) < 0;
|
|
|
446 probe = chain_end)
|
|
|
447 {
|
|
|
448 chain_end = (const fde *const*) erratic->array[probe - linear->array];
|
|
|
449 erratic->array[probe - linear->array] = NULL;
|
|
|
450 }
|
|
|
451 erratic->array[i] = (const fde *) chain_end;
|
|
|
452 chain_end = &linear->array[i];
|
|
|
453 }
|
|
|
454
|
|
|
455 /* Each entry in LINEAR which is part of the linear sequence we have
|
|
|
456 discovered will correspond to a non-NULL entry in the chain we built in
|
|
|
457 the ERRATIC array. */
|
|
|
458 for (i = j = k = 0; i < count; i++)
|
|
|
459 if (erratic->array[i])
|
|
|
460 linear->array[j++] = linear->array[i];
|
|
|
461 else
|
|
|
462 erratic->array[k++] = linear->array[i];
|
|
|
463 linear->count = j;
|
|
|
464 erratic->count = k;
|
|
|
465 }
|
|
|
466
|
|
|
467 #define SWAP(x,y) do { const fde * tmp = x; x = y; y = tmp; } while (0)
|
|
|
468
|
|
|
469 /* Convert a semi-heap to a heap. A semi-heap is a heap except possibly
|
|
|
470 for the first (root) node; push it down to its rightful place. */
|
|
|
471
|
|
|
472 static void
|
|
|
473 frame_downheap (struct object *ob, fde_compare_t fde_compare, const fde **a,
|
|
|
474 int lo, int hi)
|
|
|
475 {
|
|
|
476 int i, j;
|
|
|
477
|
|
|
478 for (i = lo, j = 2*i+1;
|
|
|
479 j < hi;
|
|
|
480 j = 2*i+1)
|
|
|
481 {
|
|
|
482 if (j+1 < hi && fde_compare (ob, a[j], a[j+1]) < 0)
|
|
|
483 ++j;
|
|
|
484
|
|
|
485 if (fde_compare (ob, a[i], a[j]) < 0)
|
|
|
486 {
|
|
|
487 SWAP (a[i], a[j]);
|
|
|
488 i = j;
|
|
|
489 }
|
|
|
490 else
|
|
|
491 break;
|
|
|
492 }
|
|
|
493 }
|
|
|
494
|
|
|
495 /* This is O(n log(n)). BSD/OS defines heapsort in stdlib.h, so we must
|
|
|
496 use a name that does not conflict. */
|
|
|
497
|
|
|
498 static void
|
|
|
499 frame_heapsort (struct object *ob, fde_compare_t fde_compare,
|
|
|
500 struct fde_vector *erratic)
|
|
|
501 {
|
|
|
502 /* For a description of this algorithm, see:
|
|
|
503 Samuel P. Harbison, Guy L. Steele Jr.: C, a reference manual, 2nd ed.,
|
|
|
504 p. 60-61. */
|
|
|
505 const fde ** a = erratic->array;
|
|
|
506 /* A portion of the array is called a "heap" if for all i>=0:
|
|
|
507 If i and 2i+1 are valid indices, then a[i] >= a[2i+1].
|
|
|
508 If i and 2i+2 are valid indices, then a[i] >= a[2i+2]. */
|
|
|
509 size_t n = erratic->count;
|
|
|
510 int m;
|
|
|
511
|
|
|
512 /* Expand our heap incrementally from the end of the array, heapifying
|
|
|
513 each resulting semi-heap as we go. After each step, a[m] is the top
|
|
|
514 of a heap. */
|
|
|
515 for (m = n/2-1; m >= 0; --m)
|
|
|
516 frame_downheap (ob, fde_compare, a, m, n);
|
|
|
517
|
|
|
518 /* Shrink our heap incrementally from the end of the array, first
|
|
|
519 swapping out the largest element a[0] and then re-heapifying the
|
|
|
520 resulting semi-heap. After each step, a[0..m) is a heap. */
|
|
|
521 for (m = n-1; m >= 1; --m)
|
|
|
522 {
|
|
|
523 SWAP (a[0], a[m]);
|
|
|
524 frame_downheap (ob, fde_compare, a, 0, m);
|
|
|
525 }
|
|
|
526 #undef SWAP
|
|
|
527 }
|
|
|
528
|
|
|
529 /* Merge V1 and V2, both sorted, and put the result into V1. */
|
|
|
530 static inline void
|
|
|
531 fde_merge (struct object *ob, fde_compare_t fde_compare,
|
|
|
532 struct fde_vector *v1, struct fde_vector *v2)
|
|
|
533 {
|
|
|
534 size_t i1, i2;
|
|
|
535 const fde * fde2;
|
|
|
536
|
|
|
537 i2 = v2->count;
|
|
|
538 if (i2 > 0)
|
|
|
539 {
|
|
|
540 i1 = v1->count;
|
|
|
541 do
|
|
|
542 {
|
|
|
543 i2--;
|
|
|
544 fde2 = v2->array[i2];
|
|
|
545 while (i1 > 0 && fde_compare (ob, v1->array[i1-1], fde2) > 0)
|
|
|
546 {
|
|
|
547 v1->array[i1+i2] = v1->array[i1-1];
|
|
|
548 i1--;
|
|
|
549 }
|
|
|
550 v1->array[i1+i2] = fde2;
|
|
|
551 }
|
|
|
552 while (i2 > 0);
|
|
|
553 v1->count += v2->count;
|
|
|
554 }
|
|
|
555 }
|
|
|
556
|
|
|
557 static inline void
|
|
|
558 end_fde_sort (struct object *ob, struct fde_accumulator *accu, size_t count)
|
|
|
559 {
|
|
|
560 fde_compare_t fde_compare;
|
|
|
561
|
|
|
562 gcc_assert (!accu->linear || accu->linear->count == count);
|
|
|
563
|
|
|
564 if (ob->s.b.mixed_encoding)
|
|
|
565 fde_compare = fde_mixed_encoding_compare;
|
|
|
566 else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
|
|
567 fde_compare = fde_unencoded_compare;
|
|
|
568 else
|
|
|
569 fde_compare = fde_single_encoding_compare;
|
|
|
570
|
|
|
571 if (accu->erratic)
|
|
|
572 {
|
|
|
573 fde_split (ob, fde_compare, accu->linear, accu->erratic);
|
|
|
574 gcc_assert (accu->linear->count + accu->erratic->count == count);
|
|
|
575 frame_heapsort (ob, fde_compare, accu->erratic);
|
|
|
576 fde_merge (ob, fde_compare, accu->linear, accu->erratic);
|
|
|
577 free (accu->erratic);
|
|
|
578 }
|
|
|
579 else
|
|
|
580 {
|
|
|
581 /* We've not managed to malloc an erratic array,
|
|
|
582 so heap sort in the linear one. */
|
|
|
583 frame_heapsort (ob, fde_compare, accu->linear);
|
|
|
584 }
|
|
|
585 }
|
|
|
586
|
|
|
587
|
|
|
588 /* Update encoding, mixed_encoding, and pc_begin for OB for the
|
|
|
589 fde array beginning at THIS_FDE. Return the number of fdes
|
|
|
590 encountered along the way. */
|
|
|
591
|
|
|
592 static size_t
|
|
|
593 classify_object_over_fdes (struct object *ob, const fde *this_fde)
|
|
|
594 {
|
|
|
595 const struct dwarf_cie *last_cie = 0;
|
|
|
596 size_t count = 0;
|
|
|
597 int encoding = DW_EH_PE_absptr;
|
|
|
598 _Unwind_Ptr base = 0;
|
|
|
599
|
|
|
600 for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
|
|
601 {
|
|
|
602 const struct dwarf_cie *this_cie;
|
|
|
603 _Unwind_Ptr mask, pc_begin;
|
|
|
604
|
|
|
605 /* Skip CIEs. */
|
|
|
606 if (this_fde->CIE_delta == 0)
|
|
|
607 continue;
|
|
|
608
|
|
|
609 /* Determine the encoding for this FDE. Note mixed encoded
|
|
|
610 objects for later. */
|
|
|
611 this_cie = get_cie (this_fde);
|
|
|
612 if (this_cie != last_cie)
|
|
|
613 {
|
|
|
614 last_cie = this_cie;
|
|
|
615 encoding = get_cie_encoding (this_cie);
|
|
|
616 base = base_from_object (encoding, ob);
|
|
|
617 if (ob->s.b.encoding == DW_EH_PE_omit)
|
|
|
618 ob->s.b.encoding = encoding;
|
|
|
619 else if (ob->s.b.encoding != encoding)
|
|
|
620 ob->s.b.mixed_encoding = 1;
|
|
|
621 }
|
|
|
622
|
|
|
623 read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
|
|
624 &pc_begin);
|
|
|
625
|
|
|
626 /* Take care to ignore link-once functions that were removed.
|
|
|
627 In these cases, the function address will be NULL, but if
|
|
|
628 the encoding is smaller than a pointer a true NULL may not
|
|
|
629 be representable. Assume 0 in the representable bits is NULL. */
|
|
|
630 mask = size_of_encoded_value (encoding);
|
|
|
631 if (mask < sizeof (void *))
|
|
36
|
632 mask = (((_Unwind_Ptr) 1) << (mask << 3)) - 1;
|
|
0
|
633 else
|
|
|
634 mask = -1;
|
|
|
635
|
|
|
636 if ((pc_begin & mask) == 0)
|
|
|
637 continue;
|
|
|
638
|
|
|
639 count += 1;
|
|
|
640 if ((void *) pc_begin < ob->pc_begin)
|
|
|
641 ob->pc_begin = (void *) pc_begin;
|
|
|
642 }
|
|
|
643
|
|
|
644 return count;
|
|
|
645 }
|
|
|
646
|
|
|
647 static void
|
|
|
648 add_fdes (struct object *ob, struct fde_accumulator *accu, const fde *this_fde)
|
|
|
649 {
|
|
|
650 const struct dwarf_cie *last_cie = 0;
|
|
|
651 int encoding = ob->s.b.encoding;
|
|
|
652 _Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
|
|
653
|
|
|
654 for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
|
|
655 {
|
|
|
656 const struct dwarf_cie *this_cie;
|
|
|
657
|
|
|
658 /* Skip CIEs. */
|
|
|
659 if (this_fde->CIE_delta == 0)
|
|
|
660 continue;
|
|
|
661
|
|
|
662 if (ob->s.b.mixed_encoding)
|
|
|
663 {
|
|
|
664 /* Determine the encoding for this FDE. Note mixed encoded
|
|
|
665 objects for later. */
|
|
|
666 this_cie = get_cie (this_fde);
|
|
|
667 if (this_cie != last_cie)
|
|
|
668 {
|
|
|
669 last_cie = this_cie;
|
|
|
670 encoding = get_cie_encoding (this_cie);
|
|
|
671 base = base_from_object (encoding, ob);
|
|
|
672 }
|
|
|
673 }
|
|
|
674
|
|
|
675 if (encoding == DW_EH_PE_absptr)
|
|
|
676 {
|
|
|
677 if (*(const _Unwind_Ptr *) this_fde->pc_begin == 0)
|
|
|
678 continue;
|
|
|
679 }
|
|
|
680 else
|
|
|
681 {
|
|
|
682 _Unwind_Ptr pc_begin, mask;
|
|
|
683
|
|
|
684 read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
|
|
685 &pc_begin);
|
|
|
686
|
|
|
687 /* Take care to ignore link-once functions that were removed.
|
|
|
688 In these cases, the function address will be NULL, but if
|
|
|
689 the encoding is smaller than a pointer a true NULL may not
|
|
|
690 be representable. Assume 0 in the representable bits is NULL. */
|
|
|
691 mask = size_of_encoded_value (encoding);
|
|
|
692 if (mask < sizeof (void *))
|
|
36
|
693 mask = (((_Unwind_Ptr) 1) << (mask << 3)) - 1;
|
|
0
|
694 else
|
|
|
695 mask = -1;
|
|
|
696
|
|
|
697 if ((pc_begin & mask) == 0)
|
|
|
698 continue;
|
|
|
699 }
|
|
|
700
|
|
|
701 fde_insert (accu, this_fde);
|
|
|
702 }
|
|
|
703 }
|
|
|
704
|
|
|
705 /* Set up a sorted array of pointers to FDEs for a loaded object. We
|
|
|
706 count up the entries before allocating the array because it's likely to
|
|
|
707 be faster. We can be called multiple times, should we have failed to
|
|
|
708 allocate a sorted fde array on a previous occasion. */
|
|
|
709
|
|
|
710 static inline void
|
|
|
711 init_object (struct object* ob)
|
|
|
712 {
|
|
|
713 struct fde_accumulator accu;
|
|
|
714 size_t count;
|
|
|
715
|
|
|
716 count = ob->s.b.count;
|
|
|
717 if (count == 0)
|
|
|
718 {
|
|
|
719 if (ob->s.b.from_array)
|
|
|
720 {
|
|
|
721 fde **p = ob->u.array;
|
|
|
722 for (count = 0; *p; ++p)
|
|
|
723 count += classify_object_over_fdes (ob, *p);
|
|
|
724 }
|
|
|
725 else
|
|
|
726 count = classify_object_over_fdes (ob, ob->u.single);
|
|
|
727
|
|
|
728 /* The count field we have in the main struct object is somewhat
|
|
|
729 limited, but should suffice for virtually all cases. If the
|
|
|
730 counted value doesn't fit, re-write a zero. The worst that
|
|
|
731 happens is that we re-count next time -- admittedly non-trivial
|
|
|
732 in that this implies some 2M fdes, but at least we function. */
|
|
|
733 ob->s.b.count = count;
|
|
|
734 if (ob->s.b.count != count)
|
|
|
735 ob->s.b.count = 0;
|
|
|
736 }
|
|
|
737
|
|
|
738 if (!start_fde_sort (&accu, count))
|
|
|
739 return;
|
|
|
740
|
|
|
741 if (ob->s.b.from_array)
|
|
|
742 {
|
|
|
743 fde **p;
|
|
|
744 for (p = ob->u.array; *p; ++p)
|
|
|
745 add_fdes (ob, &accu, *p);
|
|
|
746 }
|
|
|
747 else
|
|
|
748 add_fdes (ob, &accu, ob->u.single);
|
|
|
749
|
|
|
750 end_fde_sort (ob, &accu, count);
|
|
|
751
|
|
|
752 /* Save the original fde pointer, since this is the key by which the
|
|
|
753 DSO will deregister the object. */
|
|
|
754 accu.linear->orig_data = ob->u.single;
|
|
|
755 ob->u.sort = accu.linear;
|
|
|
756
|
|
|
757 ob->s.b.sorted = 1;
|
|
|
758 }
|
|
|
759
|
|
|
760 /* A linear search through a set of FDEs for the given PC. This is
|
|
|
761 used when there was insufficient memory to allocate and sort an
|
|
|
762 array. */
|
|
|
763
|
|
|
764 static const fde *
|
|
|
765 linear_search_fdes (struct object *ob, const fde *this_fde, void *pc)
|
|
|
766 {
|
|
|
767 const struct dwarf_cie *last_cie = 0;
|
|
|
768 int encoding = ob->s.b.encoding;
|
|
|
769 _Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
|
|
770
|
|
|
771 for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
|
|
772 {
|
|
|
773 const struct dwarf_cie *this_cie;
|
|
|
774 _Unwind_Ptr pc_begin, pc_range;
|
|
|
775
|
|
|
776 /* Skip CIEs. */
|
|
|
777 if (this_fde->CIE_delta == 0)
|
|
|
778 continue;
|
|
|
779
|
|
|
780 if (ob->s.b.mixed_encoding)
|
|
|
781 {
|
|
|
782 /* Determine the encoding for this FDE. Note mixed encoded
|
|
|
783 objects for later. */
|
|
|
784 this_cie = get_cie (this_fde);
|
|
|
785 if (this_cie != last_cie)
|
|
|
786 {
|
|
|
787 last_cie = this_cie;
|
|
|
788 encoding = get_cie_encoding (this_cie);
|
|
|
789 base = base_from_object (encoding, ob);
|
|
|
790 }
|
|
|
791 }
|
|
|
792
|
|
|
793 if (encoding == DW_EH_PE_absptr)
|
|
|
794 {
|
|
|
795 pc_begin = ((const _Unwind_Ptr *) this_fde->pc_begin)[0];
|
|
|
796 pc_range = ((const _Unwind_Ptr *) this_fde->pc_begin)[1];
|
|
|
797 if (pc_begin == 0)
|
|
|
798 continue;
|
|
|
799 }
|
|
|
800 else
|
|
|
801 {
|
|
|
802 _Unwind_Ptr mask;
|
|
|
803 const unsigned char *p;
|
|
|
804
|
|
|
805 p = read_encoded_value_with_base (encoding, base,
|
|
|
806 this_fde->pc_begin, &pc_begin);
|
|
|
807 read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
|
|
808
|
|
|
809 /* Take care to ignore link-once functions that were removed.
|
|
|
810 In these cases, the function address will be NULL, but if
|
|
|
811 the encoding is smaller than a pointer a true NULL may not
|
|
|
812 be representable. Assume 0 in the representable bits is NULL. */
|
|
|
813 mask = size_of_encoded_value (encoding);
|
|
|
814 if (mask < sizeof (void *))
|
|
36
|
815 mask = (((_Unwind_Ptr) 1) << (mask << 3)) - 1;
|
|
0
|
816 else
|
|
|
817 mask = -1;
|
|
|
818
|
|
|
819 if ((pc_begin & mask) == 0)
|
|
|
820 continue;
|
|
|
821 }
|
|
|
822
|
|
|
823 if ((_Unwind_Ptr) pc - pc_begin < pc_range)
|
|
|
824 return this_fde;
|
|
|
825 }
|
|
|
826
|
|
|
827 return NULL;
|
|
|
828 }
|
|
|
829
|
|
|
830 /* Binary search for an FDE containing the given PC. Here are three
|
|
|
831 implementations of increasing complexity. */
|
|
|
832
|
|
|
833 static inline const fde *
|
|
|
834 binary_search_unencoded_fdes (struct object *ob, void *pc)
|
|
|
835 {
|
|
|
836 struct fde_vector *vec = ob->u.sort;
|
|
|
837 size_t lo, hi;
|
|
|
838
|
|
|
839 for (lo = 0, hi = vec->count; lo < hi; )
|
|
|
840 {
|
|
|
841 size_t i = (lo + hi) / 2;
|
|
|
842 const fde *const f = vec->array[i];
|
|
|
843 const void *pc_begin = ((const void *const*) f->pc_begin)[0];
|
|
|
844 const uaddr pc_range = ((const uaddr *) f->pc_begin)[1];
|
|
|
845
|
|
|
846 if (pc < pc_begin)
|
|
|
847 hi = i;
|
|
|
848 else if (pc >= pc_begin + pc_range)
|
|
|
849 lo = i + 1;
|
|
|
850 else
|
|
|
851 return f;
|
|
|
852 }
|
|
|
853
|
|
|
854 return NULL;
|
|
|
855 }
|
|
|
856
|
|
|
857 static inline const fde *
|
|
|
858 binary_search_single_encoding_fdes (struct object *ob, void *pc)
|
|
|
859 {
|
|
|
860 struct fde_vector *vec = ob->u.sort;
|
|
|
861 int encoding = ob->s.b.encoding;
|
|
|
862 _Unwind_Ptr base = base_from_object (encoding, ob);
|
|
|
863 size_t lo, hi;
|
|
|
864
|
|
|
865 for (lo = 0, hi = vec->count; lo < hi; )
|
|
|
866 {
|
|
|
867 size_t i = (lo + hi) / 2;
|
|
|
868 const fde *f = vec->array[i];
|
|
|
869 _Unwind_Ptr pc_begin, pc_range;
|
|
|
870 const unsigned char *p;
|
|
|
871
|
|
|
872 p = read_encoded_value_with_base (encoding, base, f->pc_begin,
|
|
|
873 &pc_begin);
|
|
|
874 read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
|
|
875
|
|
|
876 if ((_Unwind_Ptr) pc < pc_begin)
|
|
|
877 hi = i;
|
|
|
878 else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
|
|
879 lo = i + 1;
|
|
|
880 else
|
|
|
881 return f;
|
|
|
882 }
|
|
|
883
|
|
|
884 return NULL;
|
|
|
885 }
|
|
|
886
|
|
|
887 static inline const fde *
|
|
|
888 binary_search_mixed_encoding_fdes (struct object *ob, void *pc)
|
|
|
889 {
|
|
|
890 struct fde_vector *vec = ob->u.sort;
|
|
|
891 size_t lo, hi;
|
|
|
892
|
|
|
893 for (lo = 0, hi = vec->count; lo < hi; )
|
|
|
894 {
|
|
|
895 size_t i = (lo + hi) / 2;
|
|
|
896 const fde *f = vec->array[i];
|
|
|
897 _Unwind_Ptr pc_begin, pc_range;
|
|
|
898 const unsigned char *p;
|
|
|
899 int encoding;
|
|
|
900
|
|
|
901 encoding = get_fde_encoding (f);
|
|
|
902 p = read_encoded_value_with_base (encoding,
|
|
|
903 base_from_object (encoding, ob),
|
|
|
904 f->pc_begin, &pc_begin);
|
|
|
905 read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
|
|
906
|
|
|
907 if ((_Unwind_Ptr) pc < pc_begin)
|
|
|
908 hi = i;
|
|
|
909 else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
|
|
910 lo = i + 1;
|
|
|
911 else
|
|
|
912 return f;
|
|
|
913 }
|
|
|
914
|
|
|
915 return NULL;
|
|
|
916 }
|
|
|
917
|
|
|
918 static const fde *
|
|
|
919 search_object (struct object* ob, void *pc)
|
|
|
920 {
|
|
|
921 /* If the data hasn't been sorted, try to do this now. We may have
|
|
|
922 more memory available than last time we tried. */
|
|
|
923 if (! ob->s.b.sorted)
|
|
|
924 {
|
|
|
925 init_object (ob);
|
|
|
926
|
|
|
927 /* Despite the above comment, the normal reason to get here is
|
|
|
928 that we've not processed this object before. A quick range
|
|
|
929 check is in order. */
|
|
|
930 if (pc < ob->pc_begin)
|
|
|
931 return NULL;
|
|
|
932 }
|
|
|
933
|
|
|
934 if (ob->s.b.sorted)
|
|
|
935 {
|
|
|
936 if (ob->s.b.mixed_encoding)
|
|
|
937 return binary_search_mixed_encoding_fdes (ob, pc);
|
|
|
938 else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
|
|
939 return binary_search_unencoded_fdes (ob, pc);
|
|
|
940 else
|
|
|
941 return binary_search_single_encoding_fdes (ob, pc);
|
|
|
942 }
|
|
|
943 else
|
|
|
944 {
|
|
|
945 /* Long slow laborious linear search, cos we've no memory. */
|
|
|
946 if (ob->s.b.from_array)
|
|
|
947 {
|
|
|
948 fde **p;
|
|
|
949 for (p = ob->u.array; *p ; p++)
|
|
|
950 {
|
|
|
951 const fde *f = linear_search_fdes (ob, *p, pc);
|
|
|
952 if (f)
|
|
|
953 return f;
|
|
|
954 }
|
|
|
955 return NULL;
|
|
|
956 }
|
|
|
957 else
|
|
|
958 return linear_search_fdes (ob, ob->u.single, pc);
|
|
|
959 }
|
|
|
960 }
|
|
|
961
|
|
|
962 const fde *
|
|
|
963 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
|
|
|
964 {
|
|
|
965 struct object *ob;
|
|
|
966 const fde *f = NULL;
|
|
|
967
|
|
|
968 init_object_mutex_once ();
|
|
|
969 __gthread_mutex_lock (&object_mutex);
|
|
|
970
|
|
|
971 /* Linear search through the classified objects, to find the one
|
|
|
972 containing the pc. Note that pc_begin is sorted descending, and
|
|
|
973 we expect objects to be non-overlapping. */
|
|
|
974 for (ob = seen_objects; ob; ob = ob->next)
|
|
|
975 if (pc >= ob->pc_begin)
|
|
|
976 {
|
|
|
977 f = search_object (ob, pc);
|
|
|
978 if (f)
|
|
|
979 goto fini;
|
|
|
980 break;
|
|
|
981 }
|
|
|
982
|
|
|
983 /* Classify and search the objects we've not yet processed. */
|
|
|
984 while ((ob = unseen_objects))
|
|
|
985 {
|
|
|
986 struct object **p;
|
|
|
987
|
|
|
988 unseen_objects = ob->next;
|
|
|
989 f = search_object (ob, pc);
|
|
|
990
|
|
|
991 /* Insert the object into the classified list. */
|
|
|
992 for (p = &seen_objects; *p ; p = &(*p)->next)
|
|
|
993 if ((*p)->pc_begin < ob->pc_begin)
|
|
|
994 break;
|
|
|
995 ob->next = *p;
|
|
|
996 *p = ob;
|
|
|
997
|
|
|
998 if (f)
|
|
|
999 goto fini;
|
|
|
1000 }
|
|
|
1001
|
|
|
1002 fini:
|
|
|
1003 __gthread_mutex_unlock (&object_mutex);
|
|
|
1004
|
|
|
1005 if (f)
|
|
|
1006 {
|
|
|
1007 int encoding;
|
|
|
1008 _Unwind_Ptr func;
|
|
|
1009
|
|
|
1010 bases->tbase = ob->tbase;
|
|
|
1011 bases->dbase = ob->dbase;
|
|
|
1012
|
|
|
1013 encoding = ob->s.b.encoding;
|
|
|
1014 if (ob->s.b.mixed_encoding)
|
|
|
1015 encoding = get_fde_encoding (f);
|
|
|
1016 read_encoded_value_with_base (encoding, base_from_object (encoding, ob),
|
|
|
1017 f->pc_begin, &func);
|
|
|
1018 bases->func = (void *) func;
|
|
|
1019 }
|
|
|
1020
|
|
|
1021 return f;
|
|
|
1022 }
|
