|
111
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1 /* Subroutines needed for unwinding stack frames for exception handling. */
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131
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2 /* Copyright (C) 1997-2018 Free Software Foundation, Inc.
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111
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3 Contributed by Jason Merrill <jason@cygnus.com>.
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|
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4
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|
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5 This file is part of GCC.
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6
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7 GCC is free software; you can redistribute it and/or modify it under
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8 the terms of the GNU General Public License as published by the Free
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|
9 Software Foundation; either version 3, or (at your option) any later
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10 version.
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11
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12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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15 for more details.
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16
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17 Under Section 7 of GPL version 3, you are granted additional
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18 permissions described in the GCC Runtime Library Exception, version
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19 3.1, as published by the Free Software Foundation.
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20
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21 You should have received a copy of the GNU General Public License and
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22 a copy of the GCC Runtime Library Exception along with this program;
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23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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24 <http://www.gnu.org/licenses/>. */
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25
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26 #ifndef _Unwind_Find_FDE
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27 #include "tconfig.h"
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28 #include "tsystem.h"
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29 #include "coretypes.h"
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30 #include "tm.h"
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31 #include "libgcc_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 #else
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39 #if (defined(__GTHREAD_MUTEX_INIT) || defined(__GTHREAD_MUTEX_INIT_FUNCTION)) \
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40 && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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41 #define ATOMIC_FDE_FAST_PATH 1
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42 #endif
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43 #endif
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44
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45 /* The unseen_objects list contains objects that have been registered
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46 but not yet categorized in any way. The seen_objects list has had
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47 its pc_begin and count fields initialized at minimum, and is sorted
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48 by decreasing value of pc_begin. */
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|
49 static struct object *unseen_objects;
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|
50 static struct object *seen_objects;
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51 #ifdef ATOMIC_FDE_FAST_PATH
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52 static int any_objects_registered;
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53 #endif
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54
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55 #ifdef __GTHREAD_MUTEX_INIT
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56 static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
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57 #define init_object_mutex_once()
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58 #else
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59 #ifdef __GTHREAD_MUTEX_INIT_FUNCTION
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60 static __gthread_mutex_t object_mutex;
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61
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62 static void
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63 init_object_mutex (void)
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64 {
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65 __GTHREAD_MUTEX_INIT_FUNCTION (&object_mutex);
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66 }
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67
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68 static void
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69 init_object_mutex_once (void)
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70 {
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71 static __gthread_once_t once = __GTHREAD_ONCE_INIT;
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72 __gthread_once (&once, init_object_mutex);
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73 }
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74 #else
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75 /* ??? Several targets include this file with stubbing parts of gthr.h
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76 and expect no locking to be done. */
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77 #define init_object_mutex_once()
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78 static __gthread_mutex_t object_mutex;
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79 #endif
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80 #endif
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81
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82 /* Called from crtbegin.o to register the unwind info for an object. */
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83
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84 void
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85 __register_frame_info_bases (const void *begin, struct object *ob,
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86 void *tbase, void *dbase)
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87 {
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88 /* If .eh_frame is empty, don't register at all. */
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89 if ((const uword *) begin == 0 || *(const uword *) begin == 0)
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90 return;
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91
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92 ob->pc_begin = (void *)-1;
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|
93 ob->tbase = tbase;
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|
94 ob->dbase = dbase;
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|
95 ob->u.single = begin;
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|
96 ob->s.i = 0;
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|
|
97 ob->s.b.encoding = DW_EH_PE_omit;
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|
98 #ifdef DWARF2_OBJECT_END_PTR_EXTENSION
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|
99 ob->fde_end = NULL;
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|
|
100 #endif
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101
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102 init_object_mutex_once ();
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103 __gthread_mutex_lock (&object_mutex);
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104
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105 ob->next = unseen_objects;
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106 unseen_objects = ob;
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107 #ifdef ATOMIC_FDE_FAST_PATH
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108 /* Set flag that at least one library has registered FDEs.
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|
109 Use relaxed MO here, it is up to the app to ensure that the library
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|
110 loading/initialization happens-before using that library in other
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111 threads (in particular unwinding with that library's functions
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|
112 appearing in the backtraces). Calling that library's functions
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|
113 without waiting for the library to initialize would be racy. */
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114 if (!any_objects_registered)
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115 __atomic_store_n (&any_objects_registered, 1, __ATOMIC_RELAXED);
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|
|
116 #endif
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117
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|
|
118 __gthread_mutex_unlock (&object_mutex);
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|
|
119 }
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120
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121 void
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122 __register_frame_info (const void *begin, struct object *ob)
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|
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123 {
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|
124 __register_frame_info_bases (begin, ob, 0, 0);
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125 }
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126
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127 void
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128 __register_frame (void *begin)
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129 {
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130 struct object *ob;
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131
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132 /* If .eh_frame is empty, don't register at all. */
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133 if (*(uword *) begin == 0)
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134 return;
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135
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136 ob = malloc (sizeof (struct object));
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|
137 __register_frame_info (begin, ob);
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138 }
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139
|
|
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140 /* Similar, but BEGIN is actually a pointer to a table of unwind entries
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141 for different translation units. Called from the file generated by
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142 collect2. */
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143
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|
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144 void
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145 __register_frame_info_table_bases (void *begin, struct object *ob,
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146 void *tbase, void *dbase)
|
|
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147 {
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|
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148 ob->pc_begin = (void *)-1;
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|
149 ob->tbase = tbase;
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150 ob->dbase = dbase;
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151 ob->u.array = begin;
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152 ob->s.i = 0;
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153 ob->s.b.from_array = 1;
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154 ob->s.b.encoding = DW_EH_PE_omit;
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155
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156 init_object_mutex_once ();
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157 __gthread_mutex_lock (&object_mutex);
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158
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|
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159 ob->next = unseen_objects;
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160 unseen_objects = ob;
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|
161 #ifdef ATOMIC_FDE_FAST_PATH
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162 /* Set flag that at least one library has registered FDEs.
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163 Use relaxed MO here, it is up to the app to ensure that the library
|
|
|
164 loading/initialization happens-before using that library in other
|
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165 threads (in particular unwinding with that library's functions
|
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166 appearing in the backtraces). Calling that library's functions
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167 without waiting for the library to initialize would be racy. */
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168 if (!any_objects_registered)
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169 __atomic_store_n (&any_objects_registered, 1, __ATOMIC_RELAXED);
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170 #endif
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171
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172 __gthread_mutex_unlock (&object_mutex);
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173 }
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174
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175 void
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176 __register_frame_info_table (void *begin, struct object *ob)
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177 {
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178 __register_frame_info_table_bases (begin, ob, 0, 0);
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179 }
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180
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181 void
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182 __register_frame_table (void *begin)
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183 {
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184 struct object *ob = malloc (sizeof (struct object));
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185 __register_frame_info_table (begin, ob);
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186 }
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187
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188 /* Called from crtbegin.o to deregister the unwind info for an object. */
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189 /* ??? Glibc has for a while now exported __register_frame_info and
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190 __deregister_frame_info. If we call __register_frame_info_bases
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191 from crtbegin (wherein it is declared weak), and this object does
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192 not get pulled from libgcc.a for other reasons, then the
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193 invocation of __deregister_frame_info will be resolved from glibc.
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194 Since the registration did not happen there, we'll die.
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195
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196 Therefore, declare a new deregistration entry point that does the
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197 exact same thing, but will resolve to the same library as
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198 implements __register_frame_info_bases. */
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199
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200 void *
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201 __deregister_frame_info_bases (const void *begin)
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202 {
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203 struct object **p;
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204 struct object *ob = 0;
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205
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206 /* If .eh_frame is empty, we haven't registered. */
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207 if ((const uword *) begin == 0 || *(const uword *) begin == 0)
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208 return ob;
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209
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210 init_object_mutex_once ();
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211 __gthread_mutex_lock (&object_mutex);
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212
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|
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213 for (p = &unseen_objects; *p ; p = &(*p)->next)
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214 if ((*p)->u.single == begin)
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215 {
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216 ob = *p;
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217 *p = ob->next;
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|
218 goto out;
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|
|
219 }
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220
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|
221 for (p = &seen_objects; *p ; p = &(*p)->next)
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222 if ((*p)->s.b.sorted)
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223 {
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224 if ((*p)->u.sort->orig_data == begin)
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225 {
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226 ob = *p;
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227 *p = ob->next;
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|
228 free (ob->u.sort);
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229 goto out;
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|
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230 }
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231 }
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232 else
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233 {
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|
|
234 if ((*p)->u.single == begin)
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235 {
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236 ob = *p;
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237 *p = ob->next;
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238 goto out;
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|
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239 }
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|
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240 }
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241
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|
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242 out:
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|
|
243 __gthread_mutex_unlock (&object_mutex);
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|
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244 gcc_assert (ob);
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|
245 return (void *) ob;
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|
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246 }
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247
|
|
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248 void *
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|
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249 __deregister_frame_info (const void *begin)
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|
|
250 {
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|
|
251 return __deregister_frame_info_bases (begin);
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|
|
252 }
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253
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254 void
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255 __deregister_frame (void *begin)
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|
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256 {
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|
|
257 /* If .eh_frame is empty, we haven't registered. */
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|
258 if (*(uword *) begin != 0)
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|
259 free (__deregister_frame_info (begin));
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260 }
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261
|
|
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262
|
|
|
263 /* Like base_of_encoded_value, but take the base from a struct object
|
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|
264 instead of an _Unwind_Context. */
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265
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266 static _Unwind_Ptr
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|
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267 base_from_object (unsigned char encoding, struct object *ob)
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|
|
268 {
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|
|
269 if (encoding == DW_EH_PE_omit)
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270 return 0;
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271
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|
|
272 switch (encoding & 0x70)
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|
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273 {
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|
|
274 case DW_EH_PE_absptr:
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|
|
275 case DW_EH_PE_pcrel:
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|
|
276 case DW_EH_PE_aligned:
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|
|
277 return 0;
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|
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278
|
|
|
279 case DW_EH_PE_textrel:
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|
|
280 return (_Unwind_Ptr) ob->tbase;
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|
|
281 case DW_EH_PE_datarel:
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|
|
282 return (_Unwind_Ptr) ob->dbase;
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|
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283 default:
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|
|
284 gcc_unreachable ();
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|
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285 }
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|
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286 }
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287
|
|
|
288 /* Return the FDE pointer encoding from the CIE. */
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|
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289 /* ??? This is a subset of extract_cie_info from unwind-dw2.c. */
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290
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|
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291 static int
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|
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292 get_cie_encoding (const struct dwarf_cie *cie)
|
|
|
293 {
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294 const unsigned char *aug, *p;
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|
295 _Unwind_Ptr dummy;
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|
|
296 _uleb128_t utmp;
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|
|
297 _sleb128_t stmp;
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298
|
|
|
299 aug = cie->augmentation;
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300 p = aug + strlen ((const char *)aug) + 1; /* Skip the augmentation string. */
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|
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301 if (__builtin_expect (cie->version >= 4, 0))
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|
|
302 {
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|
|
303 if (p[0] != sizeof (void *) || p[1] != 0)
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|
|
304 return DW_EH_PE_omit; /* We are not prepared to handle unexpected
|
|
|
305 address sizes or segment selectors. */
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|
|
306 p += 2; /* Skip address size and segment size. */
|
|
|
307 }
|
|
|
308
|
|
|
309 if (aug[0] != 'z')
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|
310 return DW_EH_PE_absptr;
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|
|
311
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|
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312 p = read_uleb128 (p, &utmp); /* Skip code alignment. */
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|
313 p = read_sleb128 (p, &stmp); /* Skip data alignment. */
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314 if (cie->version == 1) /* Skip return address column. */
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315 p++;
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|
|
316 else
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|
|
317 p = read_uleb128 (p, &utmp);
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318
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|
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319 aug++; /* Skip 'z' */
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320 p = read_uleb128 (p, &utmp); /* Skip augmentation length. */
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|
|
321 while (1)
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|
|
322 {
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|
|
323 /* This is what we're looking for. */
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324 if (*aug == 'R')
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|
325 return *p;
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|
|
326 /* Personality encoding and pointer. */
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327 else if (*aug == 'P')
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|
|
328 {
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|
|
329 /* ??? Avoid dereferencing indirect pointers, since we're
|
|
|
330 faking the base address. Gotta keep DW_EH_PE_aligned
|
|
|
331 intact, however. */
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|
|
332 p = read_encoded_value_with_base (*p & 0x7F, 0, p + 1, &dummy);
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|
|
333 }
|
|
|
334 /* LSDA encoding. */
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|
|
335 else if (*aug == 'L')
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|
|
336 p++;
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|
|
337 /* Otherwise end of string, or unknown augmentation. */
|
|
|
338 else
|
|
|
339 return DW_EH_PE_absptr;
|
|
|
340 aug++;
|
|
|
341 }
|
|
|
342 }
|
|
|
343
|
|
|
344 static inline int
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|
|
345 get_fde_encoding (const struct dwarf_fde *f)
|
|
|
346 {
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|
|
347 return get_cie_encoding (get_cie (f));
|
|
|
348 }
|
|
|
349
|
|
|
350
|
|
|
351 /* Sorting an array of FDEs by address.
|
|
|
352 (Ideally we would have the linker sort the FDEs so we don't have to do
|
|
|
353 it at run time. But the linkers are not yet prepared for this.) */
|
|
|
354
|
|
|
355 /* Comparison routines. Three variants of increasing complexity. */
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|
|
356
|
|
|
357 static int
|
|
|
358 fde_unencoded_compare (struct object *ob __attribute__((unused)),
|
|
|
359 const fde *x, const fde *y)
|
|
|
360 {
|
|
|
361 _Unwind_Ptr x_ptr, y_ptr;
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|
|
362 memcpy (&x_ptr, x->pc_begin, sizeof (_Unwind_Ptr));
|
|
|
363 memcpy (&y_ptr, y->pc_begin, sizeof (_Unwind_Ptr));
|
|
|
364
|
|
|
365 if (x_ptr > y_ptr)
|
|
|
366 return 1;
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|
|
367 if (x_ptr < y_ptr)
|
|
|
368 return -1;
|
|
|
369 return 0;
|
|
|
370 }
|
|
|
371
|
|
|
372 static int
|
|
|
373 fde_single_encoding_compare (struct object *ob, const fde *x, const fde *y)
|
|
|
374 {
|
|
|
375 _Unwind_Ptr base, x_ptr, y_ptr;
|
|
|
376
|
|
|
377 base = base_from_object (ob->s.b.encoding, ob);
|
|
|
378 read_encoded_value_with_base (ob->s.b.encoding, base, x->pc_begin, &x_ptr);
|
|
|
379 read_encoded_value_with_base (ob->s.b.encoding, base, y->pc_begin, &y_ptr);
|
|
|
380
|
|
|
381 if (x_ptr > y_ptr)
|
|
|
382 return 1;
|
|
|
383 if (x_ptr < y_ptr)
|
|
|
384 return -1;
|
|
|
385 return 0;
|
|
|
386 }
|
|
|
387
|
|
|
388 static int
|
|
|
389 fde_mixed_encoding_compare (struct object *ob, const fde *x, const fde *y)
|
|
|
390 {
|
|
|
391 int x_encoding, y_encoding;
|
|
|
392 _Unwind_Ptr x_ptr, y_ptr;
|
|
|
393
|
|
|
394 x_encoding = get_fde_encoding (x);
|
|
|
395 read_encoded_value_with_base (x_encoding, base_from_object (x_encoding, ob),
|
|
|
396 x->pc_begin, &x_ptr);
|
|
|
397
|
|
|
398 y_encoding = get_fde_encoding (y);
|
|
|
399 read_encoded_value_with_base (y_encoding, base_from_object (y_encoding, ob),
|
|
|
400 y->pc_begin, &y_ptr);
|
|
|
401
|
|
|
402 if (x_ptr > y_ptr)
|
|
|
403 return 1;
|
|
|
404 if (x_ptr < y_ptr)
|
|
|
405 return -1;
|
|
|
406 return 0;
|
|
|
407 }
|
|
|
408
|
|
|
409 typedef int (*fde_compare_t) (struct object *, const fde *, const fde *);
|
|
|
410
|
|
|
411
|
|
|
412 /* This is a special mix of insertion sort and heap sort, optimized for
|
|
|
413 the data sets that actually occur. They look like
|
|
|
414 101 102 103 127 128 105 108 110 190 111 115 119 125 160 126 129 130.
|
|
|
415 I.e. a linearly increasing sequence (coming from functions in the text
|
|
|
416 section), with additionally a few unordered elements (coming from functions
|
|
|
417 in gnu_linkonce sections) whose values are higher than the values in the
|
|
|
418 surrounding linear sequence (but not necessarily higher than the values
|
|
|
419 at the end of the linear sequence!).
|
|
|
420 The worst-case total run time is O(N) + O(n log (n)), where N is the
|
|
|
421 total number of FDEs and n is the number of erratic ones. */
|
|
|
422
|
|
|
423 struct fde_accumulator
|
|
|
424 {
|
|
|
425 struct fde_vector *linear;
|
|
|
426 struct fde_vector *erratic;
|
|
|
427 };
|
|
|
428
|
|
|
429 static inline int
|
|
|
430 start_fde_sort (struct fde_accumulator *accu, size_t count)
|
|
|
431 {
|
|
|
432 size_t size;
|
|
|
433 if (! count)
|
|
|
434 return 0;
|
|
|
435
|
|
|
436 size = sizeof (struct fde_vector) + sizeof (const fde *) * count;
|
|
|
437 if ((accu->linear = malloc (size)))
|
|
|
438 {
|
|
|
439 accu->linear->count = 0;
|
|
|
440 if ((accu->erratic = malloc (size)))
|
|
|
441 accu->erratic->count = 0;
|
|
|
442 return 1;
|
|
|
443 }
|
|
|
444 else
|
|
|
445 return 0;
|
|
|
446 }
|
|
|
447
|
|
|
448 static inline void
|
|
|
449 fde_insert (struct fde_accumulator *accu, const fde *this_fde)
|
|
|
450 {
|
|
|
451 if (accu->linear)
|
|
|
452 accu->linear->array[accu->linear->count++] = this_fde;
|
|
|
453 }
|
|
|
454
|
|
|
455 /* Split LINEAR into a linear sequence with low values and an erratic
|
|
|
456 sequence with high values, put the linear one (of longest possible
|
|
|
457 length) into LINEAR and the erratic one into ERRATIC. This is O(N).
|
|
|
458
|
|
|
459 Because the longest linear sequence we are trying to locate within the
|
|
|
460 incoming LINEAR array can be interspersed with (high valued) erratic
|
|
|
461 entries. We construct a chain indicating the sequenced entries.
|
|
|
462 To avoid having to allocate this chain, we overlay it onto the space of
|
|
|
463 the ERRATIC array during construction. A final pass iterates over the
|
|
|
464 chain to determine what should be placed in the ERRATIC array, and
|
|
|
465 what is the linear sequence. This overlay is safe from aliasing. */
|
|
|
466
|
|
|
467 static inline void
|
|
|
468 fde_split (struct object *ob, fde_compare_t fde_compare,
|
|
|
469 struct fde_vector *linear, struct fde_vector *erratic)
|
|
|
470 {
|
|
|
471 static const fde *marker;
|
|
|
472 size_t count = linear->count;
|
|
|
473 const fde *const *chain_end = ▮
|
|
|
474 size_t i, j, k;
|
|
|
475
|
|
|
476 /* This should optimize out, but it is wise to make sure this assumption
|
|
|
477 is correct. Should these have different sizes, we cannot cast between
|
|
|
478 them and the overlaying onto ERRATIC will not work. */
|
|
|
479 gcc_assert (sizeof (const fde *) == sizeof (const fde **));
|
|
|
480
|
|
|
481 for (i = 0; i < count; i++)
|
|
|
482 {
|
|
|
483 const fde *const *probe;
|
|
|
484
|
|
|
485 for (probe = chain_end;
|
|
|
486 probe != &marker && fde_compare (ob, linear->array[i], *probe) < 0;
|
|
|
487 probe = chain_end)
|
|
|
488 {
|
|
|
489 chain_end = (const fde *const*) erratic->array[probe - linear->array];
|
|
|
490 erratic->array[probe - linear->array] = NULL;
|
|
|
491 }
|
|
|
492 erratic->array[i] = (const fde *) chain_end;
|
|
|
493 chain_end = &linear->array[i];
|
|
|
494 }
|
|
|
495
|
|
|
496 /* Each entry in LINEAR which is part of the linear sequence we have
|
|
|
497 discovered will correspond to a non-NULL entry in the chain we built in
|
|
|
498 the ERRATIC array. */
|
|
|
499 for (i = j = k = 0; i < count; i++)
|
|
|
500 if (erratic->array[i])
|
|
|
501 linear->array[j++] = linear->array[i];
|
|
|
502 else
|
|
|
503 erratic->array[k++] = linear->array[i];
|
|
|
504 linear->count = j;
|
|
|
505 erratic->count = k;
|
|
|
506 }
|
|
|
507
|
|
|
508 #define SWAP(x,y) do { const fde * tmp = x; x = y; y = tmp; } while (0)
|
|
|
509
|
|
|
510 /* Convert a semi-heap to a heap. A semi-heap is a heap except possibly
|
|
|
511 for the first (root) node; push it down to its rightful place. */
|
|
|
512
|
|
|
513 static void
|
|
|
514 frame_downheap (struct object *ob, fde_compare_t fde_compare, const fde **a,
|
|
|
515 int lo, int hi)
|
|
|
516 {
|
|
|
517 int i, j;
|
|
|
518
|
|
|
519 for (i = lo, j = 2*i+1;
|
|
|
520 j < hi;
|
|
|
521 j = 2*i+1)
|
|
|
522 {
|
|
|
523 if (j+1 < hi && fde_compare (ob, a[j], a[j+1]) < 0)
|
|
|
524 ++j;
|
|
|
525
|
|
|
526 if (fde_compare (ob, a[i], a[j]) < 0)
|
|
|
527 {
|
|
|
528 SWAP (a[i], a[j]);
|
|
|
529 i = j;
|
|
|
530 }
|
|
|
531 else
|
|
|
532 break;
|
|
|
533 }
|
|
|
534 }
|
|
|
535
|
|
|
536 /* This is O(n log(n)). BSD/OS defines heapsort in stdlib.h, so we must
|
|
|
537 use a name that does not conflict. */
|
|
|
538
|
|
|
539 static void
|
|
|
540 frame_heapsort (struct object *ob, fde_compare_t fde_compare,
|
|
|
541 struct fde_vector *erratic)
|
|
|
542 {
|
|
|
543 /* For a description of this algorithm, see:
|
|
|
544 Samuel P. Harbison, Guy L. Steele Jr.: C, a reference manual, 2nd ed.,
|
|
|
545 p. 60-61. */
|
|
|
546 const fde ** a = erratic->array;
|
|
|
547 /* A portion of the array is called a "heap" if for all i>=0:
|
|
|
548 If i and 2i+1 are valid indices, then a[i] >= a[2i+1].
|
|
|
549 If i and 2i+2 are valid indices, then a[i] >= a[2i+2]. */
|
|
|
550 size_t n = erratic->count;
|
|
|
551 int m;
|
|
|
552
|
|
|
553 /* Expand our heap incrementally from the end of the array, heapifying
|
|
|
554 each resulting semi-heap as we go. After each step, a[m] is the top
|
|
|
555 of a heap. */
|
|
|
556 for (m = n/2-1; m >= 0; --m)
|
|
|
557 frame_downheap (ob, fde_compare, a, m, n);
|
|
|
558
|
|
|
559 /* Shrink our heap incrementally from the end of the array, first
|
|
|
560 swapping out the largest element a[0] and then re-heapifying the
|
|
|
561 resulting semi-heap. After each step, a[0..m) is a heap. */
|
|
|
562 for (m = n-1; m >= 1; --m)
|
|
|
563 {
|
|
|
564 SWAP (a[0], a[m]);
|
|
|
565 frame_downheap (ob, fde_compare, a, 0, m);
|
|
|
566 }
|
|
|
567 #undef SWAP
|
|
|
568 }
|
|
|
569
|
|
|
570 /* Merge V1 and V2, both sorted, and put the result into V1. */
|
|
|
571 static inline void
|
|
|
572 fde_merge (struct object *ob, fde_compare_t fde_compare,
|
|
|
573 struct fde_vector *v1, struct fde_vector *v2)
|
|
|
574 {
|
|
|
575 size_t i1, i2;
|
|
|
576 const fde * fde2;
|
|
|
577
|
|
|
578 i2 = v2->count;
|
|
|
579 if (i2 > 0)
|
|
|
580 {
|
|
|
581 i1 = v1->count;
|
|
|
582 do
|
|
|
583 {
|
|
|
584 i2--;
|
|
|
585 fde2 = v2->array[i2];
|
|
|
586 while (i1 > 0 && fde_compare (ob, v1->array[i1-1], fde2) > 0)
|
|
|
587 {
|
|
|
588 v1->array[i1+i2] = v1->array[i1-1];
|
|
|
589 i1--;
|
|
|
590 }
|
|
|
591 v1->array[i1+i2] = fde2;
|
|
|
592 }
|
|
|
593 while (i2 > 0);
|
|
|
594 v1->count += v2->count;
|
|
|
595 }
|
|
|
596 }
|
|
|
597
|
|
|
598 static inline void
|
|
|
599 end_fde_sort (struct object *ob, struct fde_accumulator *accu, size_t count)
|
|
|
600 {
|
|
|
601 fde_compare_t fde_compare;
|
|
|
602
|
|
|
603 gcc_assert (!accu->linear || accu->linear->count == count);
|
|
|
604
|
|
|
605 if (ob->s.b.mixed_encoding)
|
|
|
606 fde_compare = fde_mixed_encoding_compare;
|
|
|
607 else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
|
|
608 fde_compare = fde_unencoded_compare;
|
|
|
609 else
|
|
|
610 fde_compare = fde_single_encoding_compare;
|
|
|
611
|
|
|
612 if (accu->erratic)
|
|
|
613 {
|
|
|
614 fde_split (ob, fde_compare, accu->linear, accu->erratic);
|
|
|
615 gcc_assert (accu->linear->count + accu->erratic->count == count);
|
|
|
616 frame_heapsort (ob, fde_compare, accu->erratic);
|
|
|
617 fde_merge (ob, fde_compare, accu->linear, accu->erratic);
|
|
|
618 free (accu->erratic);
|
|
|
619 }
|
|
|
620 else
|
|
|
621 {
|
|
|
622 /* We've not managed to malloc an erratic array,
|
|
|
623 so heap sort in the linear one. */
|
|
|
624 frame_heapsort (ob, fde_compare, accu->linear);
|
|
|
625 }
|
|
|
626 }
|
|
|
627
|
|
|
628
|
|
|
629 /* Update encoding, mixed_encoding, and pc_begin for OB for the
|
|
|
630 fde array beginning at THIS_FDE. Return the number of fdes
|
|
|
631 encountered along the way. */
|
|
|
632
|
|
|
633 static size_t
|
|
|
634 classify_object_over_fdes (struct object *ob, const fde *this_fde)
|
|
|
635 {
|
|
|
636 const struct dwarf_cie *last_cie = 0;
|
|
|
637 size_t count = 0;
|
|
|
638 int encoding = DW_EH_PE_absptr;
|
|
|
639 _Unwind_Ptr base = 0;
|
|
|
640
|
|
|
641 for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
|
|
642 {
|
|
|
643 const struct dwarf_cie *this_cie;
|
|
|
644 _Unwind_Ptr mask, pc_begin;
|
|
|
645
|
|
|
646 /* Skip CIEs. */
|
|
|
647 if (this_fde->CIE_delta == 0)
|
|
|
648 continue;
|
|
|
649
|
|
|
650 /* Determine the encoding for this FDE. Note mixed encoded
|
|
|
651 objects for later. */
|
|
|
652 this_cie = get_cie (this_fde);
|
|
|
653 if (this_cie != last_cie)
|
|
|
654 {
|
|
|
655 last_cie = this_cie;
|
|
|
656 encoding = get_cie_encoding (this_cie);
|
|
|
657 if (encoding == DW_EH_PE_omit)
|
|
|
658 return -1;
|
|
|
659 base = base_from_object (encoding, ob);
|
|
|
660 if (ob->s.b.encoding == DW_EH_PE_omit)
|
|
|
661 ob->s.b.encoding = encoding;
|
|
|
662 else if (ob->s.b.encoding != encoding)
|
|
|
663 ob->s.b.mixed_encoding = 1;
|
|
|
664 }
|
|
|
665
|
|
|
666 read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
|
|
667 &pc_begin);
|
|
|
668
|
|
|
669 /* Take care to ignore link-once functions that were removed.
|
|
|
670 In these cases, the function address will be NULL, but if
|
|
|
671 the encoding is smaller than a pointer a true NULL may not
|
|
|
672 be representable. Assume 0 in the representable bits is NULL. */
|
|
|
673 mask = size_of_encoded_value (encoding);
|
|
|
674 if (mask < sizeof (void *))
|
|
|
675 mask = (((_Unwind_Ptr) 1) << (mask << 3)) - 1;
|
|
|
676 else
|
|
|
677 mask = -1;
|
|
|
678
|
|
|
679 if ((pc_begin & mask) == 0)
|
|
|
680 continue;
|
|
|
681
|
|
|
682 count += 1;
|
|
|
683 if ((void *) pc_begin < ob->pc_begin)
|
|
|
684 ob->pc_begin = (void *) pc_begin;
|
|
|
685 }
|
|
|
686
|
|
|
687 return count;
|
|
|
688 }
|
|
|
689
|
|
|
690 static void
|
|
|
691 add_fdes (struct object *ob, struct fde_accumulator *accu, const fde *this_fde)
|
|
|
692 {
|
|
|
693 const struct dwarf_cie *last_cie = 0;
|
|
|
694 int encoding = ob->s.b.encoding;
|
|
|
695 _Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
|
|
696
|
|
|
697 for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
|
|
698 {
|
|
|
699 const struct dwarf_cie *this_cie;
|
|
|
700
|
|
|
701 /* Skip CIEs. */
|
|
|
702 if (this_fde->CIE_delta == 0)
|
|
|
703 continue;
|
|
|
704
|
|
|
705 if (ob->s.b.mixed_encoding)
|
|
|
706 {
|
|
|
707 /* Determine the encoding for this FDE. Note mixed encoded
|
|
|
708 objects for later. */
|
|
|
709 this_cie = get_cie (this_fde);
|
|
|
710 if (this_cie != last_cie)
|
|
|
711 {
|
|
|
712 last_cie = this_cie;
|
|
|
713 encoding = get_cie_encoding (this_cie);
|
|
|
714 base = base_from_object (encoding, ob);
|
|
|
715 }
|
|
|
716 }
|
|
|
717
|
|
|
718 if (encoding == DW_EH_PE_absptr)
|
|
|
719 {
|
|
|
720 _Unwind_Ptr ptr;
|
|
|
721 memcpy (&ptr, this_fde->pc_begin, sizeof (_Unwind_Ptr));
|
|
|
722 if (ptr == 0)
|
|
|
723 continue;
|
|
|
724 }
|
|
|
725 else
|
|
|
726 {
|
|
|
727 _Unwind_Ptr pc_begin, mask;
|
|
|
728
|
|
|
729 read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
|
|
730 &pc_begin);
|
|
|
731
|
|
|
732 /* Take care to ignore link-once functions that were removed.
|
|
|
733 In these cases, the function address will be NULL, but if
|
|
|
734 the encoding is smaller than a pointer a true NULL may not
|
|
|
735 be representable. Assume 0 in the representable bits is NULL. */
|
|
|
736 mask = size_of_encoded_value (encoding);
|
|
|
737 if (mask < sizeof (void *))
|
|
|
738 mask = (((_Unwind_Ptr) 1) << (mask << 3)) - 1;
|
|
|
739 else
|
|
|
740 mask = -1;
|
|
|
741
|
|
|
742 if ((pc_begin & mask) == 0)
|
|
|
743 continue;
|
|
|
744 }
|
|
|
745
|
|
|
746 fde_insert (accu, this_fde);
|
|
|
747 }
|
|
|
748 }
|
|
|
749
|
|
|
750 /* Set up a sorted array of pointers to FDEs for a loaded object. We
|
|
|
751 count up the entries before allocating the array because it's likely to
|
|
|
752 be faster. We can be called multiple times, should we have failed to
|
|
|
753 allocate a sorted fde array on a previous occasion. */
|
|
|
754
|
|
|
755 static inline void
|
|
|
756 init_object (struct object* ob)
|
|
|
757 {
|
|
|
758 struct fde_accumulator accu;
|
|
|
759 size_t count;
|
|
|
760
|
|
|
761 count = ob->s.b.count;
|
|
|
762 if (count == 0)
|
|
|
763 {
|
|
|
764 if (ob->s.b.from_array)
|
|
|
765 {
|
|
|
766 fde **p = ob->u.array;
|
|
|
767 for (count = 0; *p; ++p)
|
|
|
768 {
|
|
|
769 size_t cur_count = classify_object_over_fdes (ob, *p);
|
|
|
770 if (cur_count == (size_t) -1)
|
|
|
771 goto unhandled_fdes;
|
|
|
772 count += cur_count;
|
|
|
773 }
|
|
|
774 }
|
|
|
775 else
|
|
|
776 {
|
|
|
777 count = classify_object_over_fdes (ob, ob->u.single);
|
|
|
778 if (count == (size_t) -1)
|
|
|
779 {
|
|
|
780 static const fde terminator;
|
|
|
781 unhandled_fdes:
|
|
|
782 ob->s.i = 0;
|
|
|
783 ob->s.b.encoding = DW_EH_PE_omit;
|
|
|
784 ob->u.single = &terminator;
|
|
|
785 return;
|
|
|
786 }
|
|
|
787 }
|
|
|
788
|
|
|
789 /* The count field we have in the main struct object is somewhat
|
|
|
790 limited, but should suffice for virtually all cases. If the
|
|
|
791 counted value doesn't fit, re-write a zero. The worst that
|
|
|
792 happens is that we re-count next time -- admittedly non-trivial
|
|
|
793 in that this implies some 2M fdes, but at least we function. */
|
|
|
794 ob->s.b.count = count;
|
|
|
795 if (ob->s.b.count != count)
|
|
|
796 ob->s.b.count = 0;
|
|
|
797 }
|
|
|
798
|
|
|
799 if (!start_fde_sort (&accu, count))
|
|
|
800 return;
|
|
|
801
|
|
|
802 if (ob->s.b.from_array)
|
|
|
803 {
|
|
|
804 fde **p;
|
|
|
805 for (p = ob->u.array; *p; ++p)
|
|
|
806 add_fdes (ob, &accu, *p);
|
|
|
807 }
|
|
|
808 else
|
|
|
809 add_fdes (ob, &accu, ob->u.single);
|
|
|
810
|
|
|
811 end_fde_sort (ob, &accu, count);
|
|
|
812
|
|
|
813 /* Save the original fde pointer, since this is the key by which the
|
|
|
814 DSO will deregister the object. */
|
|
|
815 accu.linear->orig_data = ob->u.single;
|
|
|
816 ob->u.sort = accu.linear;
|
|
|
817
|
|
|
818 ob->s.b.sorted = 1;
|
|
|
819 }
|
|
|
820
|
|
|
821 /* A linear search through a set of FDEs for the given PC. This is
|
|
|
822 used when there was insufficient memory to allocate and sort an
|
|
|
823 array. */
|
|
|
824
|
|
|
825 static const fde *
|
|
|
826 linear_search_fdes (struct object *ob, const fde *this_fde, void *pc)
|
|
|
827 {
|
|
|
828 const struct dwarf_cie *last_cie = 0;
|
|
|
829 int encoding = ob->s.b.encoding;
|
|
|
830 _Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
|
|
831
|
|
|
832 for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
|
|
833 {
|
|
|
834 const struct dwarf_cie *this_cie;
|
|
|
835 _Unwind_Ptr pc_begin, pc_range;
|
|
|
836
|
|
|
837 /* Skip CIEs. */
|
|
|
838 if (this_fde->CIE_delta == 0)
|
|
|
839 continue;
|
|
|
840
|
|
|
841 if (ob->s.b.mixed_encoding)
|
|
|
842 {
|
|
|
843 /* Determine the encoding for this FDE. Note mixed encoded
|
|
|
844 objects for later. */
|
|
|
845 this_cie = get_cie (this_fde);
|
|
|
846 if (this_cie != last_cie)
|
|
|
847 {
|
|
|
848 last_cie = this_cie;
|
|
|
849 encoding = get_cie_encoding (this_cie);
|
|
|
850 base = base_from_object (encoding, ob);
|
|
|
851 }
|
|
|
852 }
|
|
|
853
|
|
|
854 if (encoding == DW_EH_PE_absptr)
|
|
|
855 {
|
|
|
856 const _Unwind_Ptr *pc_array = (const _Unwind_Ptr *) this_fde->pc_begin;
|
|
|
857 pc_begin = pc_array[0];
|
|
|
858 pc_range = pc_array[1];
|
|
|
859 if (pc_begin == 0)
|
|
|
860 continue;
|
|
|
861 }
|
|
|
862 else
|
|
|
863 {
|
|
|
864 _Unwind_Ptr mask;
|
|
|
865 const unsigned char *p;
|
|
|
866
|
|
|
867 p = read_encoded_value_with_base (encoding, base,
|
|
|
868 this_fde->pc_begin, &pc_begin);
|
|
|
869 read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
|
|
870
|
|
|
871 /* Take care to ignore link-once functions that were removed.
|
|
|
872 In these cases, the function address will be NULL, but if
|
|
|
873 the encoding is smaller than a pointer a true NULL may not
|
|
|
874 be representable. Assume 0 in the representable bits is NULL. */
|
|
|
875 mask = size_of_encoded_value (encoding);
|
|
|
876 if (mask < sizeof (void *))
|
|
|
877 mask = (((_Unwind_Ptr) 1) << (mask << 3)) - 1;
|
|
|
878 else
|
|
|
879 mask = -1;
|
|
|
880
|
|
|
881 if ((pc_begin & mask) == 0)
|
|
|
882 continue;
|
|
|
883 }
|
|
|
884
|
|
|
885 if ((_Unwind_Ptr) pc - pc_begin < pc_range)
|
|
|
886 return this_fde;
|
|
|
887 }
|
|
|
888
|
|
|
889 return NULL;
|
|
|
890 }
|
|
|
891
|
|
|
892 /* Binary search for an FDE containing the given PC. Here are three
|
|
|
893 implementations of increasing complexity. */
|
|
|
894
|
|
|
895 static inline const fde *
|
|
|
896 binary_search_unencoded_fdes (struct object *ob, void *pc)
|
|
|
897 {
|
|
|
898 struct fde_vector *vec = ob->u.sort;
|
|
|
899 size_t lo, hi;
|
|
|
900
|
|
|
901 for (lo = 0, hi = vec->count; lo < hi; )
|
|
|
902 {
|
|
|
903 size_t i = (lo + hi) / 2;
|
|
|
904 const fde *const f = vec->array[i];
|
|
|
905 void *pc_begin;
|
|
|
906 uaddr pc_range;
|
|
|
907 memcpy (&pc_begin, (const void * const *) f->pc_begin, sizeof (void *));
|
|
|
908 memcpy (&pc_range, (const uaddr *) f->pc_begin + 1, sizeof (uaddr));
|
|
|
909
|
|
|
910 if (pc < pc_begin)
|
|
|
911 hi = i;
|
|
|
912 else if (pc >= pc_begin + pc_range)
|
|
|
913 lo = i + 1;
|
|
|
914 else
|
|
|
915 return f;
|
|
|
916 }
|
|
|
917
|
|
|
918 return NULL;
|
|
|
919 }
|
|
|
920
|
|
|
921 static inline const fde *
|
|
|
922 binary_search_single_encoding_fdes (struct object *ob, void *pc)
|
|
|
923 {
|
|
|
924 struct fde_vector *vec = ob->u.sort;
|
|
|
925 int encoding = ob->s.b.encoding;
|
|
|
926 _Unwind_Ptr base = base_from_object (encoding, ob);
|
|
|
927 size_t lo, hi;
|
|
|
928
|
|
|
929 for (lo = 0, hi = vec->count; lo < hi; )
|
|
|
930 {
|
|
|
931 size_t i = (lo + hi) / 2;
|
|
|
932 const fde *f = vec->array[i];
|
|
|
933 _Unwind_Ptr pc_begin, pc_range;
|
|
|
934 const unsigned char *p;
|
|
|
935
|
|
|
936 p = read_encoded_value_with_base (encoding, base, f->pc_begin,
|
|
|
937 &pc_begin);
|
|
|
938 read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
|
|
939
|
|
|
940 if ((_Unwind_Ptr) pc < pc_begin)
|
|
|
941 hi = i;
|
|
|
942 else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
|
|
943 lo = i + 1;
|
|
|
944 else
|
|
|
945 return f;
|
|
|
946 }
|
|
|
947
|
|
|
948 return NULL;
|
|
|
949 }
|
|
|
950
|
|
|
951 static inline const fde *
|
|
|
952 binary_search_mixed_encoding_fdes (struct object *ob, void *pc)
|
|
|
953 {
|
|
|
954 struct fde_vector *vec = ob->u.sort;
|
|
|
955 size_t lo, hi;
|
|
|
956
|
|
|
957 for (lo = 0, hi = vec->count; lo < hi; )
|
|
|
958 {
|
|
|
959 size_t i = (lo + hi) / 2;
|
|
|
960 const fde *f = vec->array[i];
|
|
|
961 _Unwind_Ptr pc_begin, pc_range;
|
|
|
962 const unsigned char *p;
|
|
|
963 int encoding;
|
|
|
964
|
|
|
965 encoding = get_fde_encoding (f);
|
|
|
966 p = read_encoded_value_with_base (encoding,
|
|
|
967 base_from_object (encoding, ob),
|
|
|
968 f->pc_begin, &pc_begin);
|
|
|
969 read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
|
|
970
|
|
|
971 if ((_Unwind_Ptr) pc < pc_begin)
|
|
|
972 hi = i;
|
|
|
973 else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
|
|
974 lo = i + 1;
|
|
|
975 else
|
|
|
976 return f;
|
|
|
977 }
|
|
|
978
|
|
|
979 return NULL;
|
|
|
980 }
|
|
|
981
|
|
|
982 static const fde *
|
|
|
983 search_object (struct object* ob, void *pc)
|
|
|
984 {
|
|
|
985 /* If the data hasn't been sorted, try to do this now. We may have
|
|
|
986 more memory available than last time we tried. */
|
|
|
987 if (! ob->s.b.sorted)
|
|
|
988 {
|
|
|
989 init_object (ob);
|
|
|
990
|
|
|
991 /* Despite the above comment, the normal reason to get here is
|
|
|
992 that we've not processed this object before. A quick range
|
|
|
993 check is in order. */
|
|
|
994 if (pc < ob->pc_begin)
|
|
|
995 return NULL;
|
|
|
996 }
|
|
|
997
|
|
|
998 if (ob->s.b.sorted)
|
|
|
999 {
|
|
|
1000 if (ob->s.b.mixed_encoding)
|
|
|
1001 return binary_search_mixed_encoding_fdes (ob, pc);
|
|
|
1002 else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
|
|
1003 return binary_search_unencoded_fdes (ob, pc);
|
|
|
1004 else
|
|
|
1005 return binary_search_single_encoding_fdes (ob, pc);
|
|
|
1006 }
|
|
|
1007 else
|
|
|
1008 {
|
|
|
1009 /* Long slow laborious linear search, cos we've no memory. */
|
|
|
1010 if (ob->s.b.from_array)
|
|
|
1011 {
|
|
|
1012 fde **p;
|
|
|
1013 for (p = ob->u.array; *p ; p++)
|
|
|
1014 {
|
|
|
1015 const fde *f = linear_search_fdes (ob, *p, pc);
|
|
|
1016 if (f)
|
|
|
1017 return f;
|
|
|
1018 }
|
|
|
1019 return NULL;
|
|
|
1020 }
|
|
|
1021 else
|
|
|
1022 return linear_search_fdes (ob, ob->u.single, pc);
|
|
|
1023 }
|
|
|
1024 }
|
|
|
1025
|
|
|
1026 const fde *
|
|
|
1027 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
|
|
|
1028 {
|
|
|
1029 struct object *ob;
|
|
|
1030 const fde *f = NULL;
|
|
|
1031
|
|
|
1032 #ifdef ATOMIC_FDE_FAST_PATH
|
|
|
1033 /* For targets where unwind info is usually not registered through these
|
|
|
1034 APIs anymore, avoid taking a global lock.
|
|
|
1035 Use relaxed MO here, it is up to the app to ensure that the library
|
|
|
1036 loading/initialization happens-before using that library in other
|
|
|
1037 threads (in particular unwinding with that library's functions
|
|
|
1038 appearing in the backtraces). Calling that library's functions
|
|
|
1039 without waiting for the library to initialize would be racy. */
|
|
|
1040 if (__builtin_expect (!__atomic_load_n (&any_objects_registered,
|
|
|
1041 __ATOMIC_RELAXED), 1))
|
|
|
1042 return NULL;
|
|
|
1043 #endif
|
|
|
1044
|
|
|
1045 init_object_mutex_once ();
|
|
|
1046 __gthread_mutex_lock (&object_mutex);
|
|
|
1047
|
|
|
1048 /* Linear search through the classified objects, to find the one
|
|
|
1049 containing the pc. Note that pc_begin is sorted descending, and
|
|
|
1050 we expect objects to be non-overlapping. */
|
|
|
1051 for (ob = seen_objects; ob; ob = ob->next)
|
|
|
1052 if (pc >= ob->pc_begin)
|
|
|
1053 {
|
|
|
1054 f = search_object (ob, pc);
|
|
|
1055 if (f)
|
|
|
1056 goto fini;
|
|
|
1057 break;
|
|
|
1058 }
|
|
|
1059
|
|
|
1060 /* Classify and search the objects we've not yet processed. */
|
|
|
1061 while ((ob = unseen_objects))
|
|
|
1062 {
|
|
|
1063 struct object **p;
|
|
|
1064
|
|
|
1065 unseen_objects = ob->next;
|
|
|
1066 f = search_object (ob, pc);
|
|
|
1067
|
|
|
1068 /* Insert the object into the classified list. */
|
|
|
1069 for (p = &seen_objects; *p ; p = &(*p)->next)
|
|
|
1070 if ((*p)->pc_begin < ob->pc_begin)
|
|
|
1071 break;
|
|
|
1072 ob->next = *p;
|
|
|
1073 *p = ob;
|
|
|
1074
|
|
|
1075 if (f)
|
|
|
1076 goto fini;
|
|
|
1077 }
|
|
|
1078
|
|
|
1079 fini:
|
|
|
1080 __gthread_mutex_unlock (&object_mutex);
|
|
|
1081
|
|
|
1082 if (f)
|
|
|
1083 {
|
|
|
1084 int encoding;
|
|
|
1085 _Unwind_Ptr func;
|
|
|
1086
|
|
|
1087 bases->tbase = ob->tbase;
|
|
|
1088 bases->dbase = ob->dbase;
|
|
|
1089
|
|
|
1090 encoding = ob->s.b.encoding;
|
|
|
1091 if (ob->s.b.mixed_encoding)
|
|
|
1092 encoding = get_fde_encoding (f);
|
|
|
1093 read_encoded_value_with_base (encoding, base_from_object (encoding, ob),
|
|
|
1094 f->pc_begin, &func);
|
|
|
1095 bases->func = (void *) func;
|
|
|
1096 }
|
|
|
1097
|
|
|
1098 return f;
|
|
|
1099 }
|
