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111
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1 /* Optimize and expand sanitizer functions.
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131
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2 Copyright (C) 2014-2018 Free Software Foundation, Inc.
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111
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3 Contributed by Marek Polacek <polacek@redhat.com>
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4
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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 You should have received a copy of the GNU General Public License
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18 along with GCC; see the file COPYING3. If not see
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19 <http://www.gnu.org/licenses/>. */
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20
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21 #include "config.h"
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22 #include "system.h"
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23 #include "coretypes.h"
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24 #include "backend.h"
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25 #include "tree.h"
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26 #include "gimple.h"
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27 #include "ssa.h"
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28 #include "tree-pass.h"
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29 #include "tree-ssa-operands.h"
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30 #include "gimple-pretty-print.h"
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31 #include "fold-const.h"
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32 #include "gimple-iterator.h"
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33 #include "stringpool.h"
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34 #include "attribs.h"
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35 #include "asan.h"
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36 #include "ubsan.h"
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37 #include "params.h"
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38 #include "tree-hash-traits.h"
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39 #include "gimple-ssa.h"
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40 #include "tree-phinodes.h"
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41 #include "ssa-iterators.h"
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42 #include "gimplify.h"
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43 #include "gimple-iterator.h"
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44 #include "gimple-walk.h"
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45 #include "cfghooks.h"
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46 #include "tree-dfa.h"
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47 #include "tree-ssa.h"
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48 #include "varasm.h"
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49
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50 /* This is used to carry information about basic blocks. It is
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51 attached to the AUX field of the standard CFG block. */
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52
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53 struct sanopt_info
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54 {
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55 /* True if this BB might call (directly or indirectly) free/munmap
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56 or similar operation. */
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57 bool has_freeing_call_p;
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58
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59 /* True if HAS_FREEING_CALL_P flag has been computed. */
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60 bool has_freeing_call_computed_p;
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61
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62 /* True if there is a block with HAS_FREEING_CALL_P flag set
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63 on any path between an immediate dominator of BB, denoted
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64 imm(BB), and BB. */
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65 bool imm_dom_path_with_freeing_call_p;
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66
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67 /* True if IMM_DOM_PATH_WITH_FREEING_CALL_P has been computed. */
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68 bool imm_dom_path_with_freeing_call_computed_p;
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69
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70 /* Number of possibly freeing calls encountered in this bb
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71 (so far). */
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72 uint64_t freeing_call_events;
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73
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74 /* True if BB is currently being visited during computation
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75 of IMM_DOM_PATH_WITH_FREEING_CALL_P flag. */
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76 bool being_visited_p;
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77
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78 /* True if this BB has been visited in the dominator walk. */
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79 bool visited_p;
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80 };
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81
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82 /* If T has a single definition of form T = T2, return T2. */
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83
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84 static tree
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85 maybe_get_single_definition (tree t)
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86 {
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87 if (TREE_CODE (t) == SSA_NAME)
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88 {
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89 gimple *g = SSA_NAME_DEF_STMT (t);
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90 if (gimple_assign_single_p (g))
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91 return gimple_assign_rhs1 (g);
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92 }
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93 return NULL_TREE;
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94 }
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95
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96 /* Tree triplet for vptr_check_map. */
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97 struct sanopt_tree_triplet
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98 {
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99 tree t1, t2, t3;
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100 };
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101
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102 /* Traits class for tree triplet hash maps below. */
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103
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104 struct sanopt_tree_triplet_hash : typed_noop_remove <sanopt_tree_triplet>
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105 {
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106 typedef sanopt_tree_triplet value_type;
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107 typedef sanopt_tree_triplet compare_type;
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108
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109 static hashval_t
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110 hash (const sanopt_tree_triplet &ref)
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111 {
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112 inchash::hash hstate (0);
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113 inchash::add_expr (ref.t1, hstate);
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114 inchash::add_expr (ref.t2, hstate);
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115 inchash::add_expr (ref.t3, hstate);
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116 return hstate.end ();
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117 }
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118
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119 static bool
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120 equal (const sanopt_tree_triplet &ref1, const sanopt_tree_triplet &ref2)
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121 {
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122 return operand_equal_p (ref1.t1, ref2.t1, 0)
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123 && operand_equal_p (ref1.t2, ref2.t2, 0)
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124 && operand_equal_p (ref1.t3, ref2.t3, 0);
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125 }
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126
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127 static void
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128 mark_deleted (sanopt_tree_triplet &ref)
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129 {
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130 ref.t1 = reinterpret_cast<tree> (1);
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131 }
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132
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133 static void
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134 mark_empty (sanopt_tree_triplet &ref)
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135 {
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136 ref.t1 = NULL;
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137 }
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138
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139 static bool
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140 is_deleted (const sanopt_tree_triplet &ref)
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141 {
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142 return ref.t1 == reinterpret_cast<tree> (1);
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143 }
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144
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145 static bool
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146 is_empty (const sanopt_tree_triplet &ref)
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147 {
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148 return ref.t1 == NULL;
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149 }
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150 };
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151
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152 /* Tree couple for ptr_check_map. */
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153 struct sanopt_tree_couple
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154 {
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155 tree ptr;
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156 bool pos_p;
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157 };
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158
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159 /* Traits class for tree triplet hash maps below. */
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160
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161 struct sanopt_tree_couple_hash : typed_noop_remove <sanopt_tree_couple>
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162 {
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163 typedef sanopt_tree_couple value_type;
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164 typedef sanopt_tree_couple compare_type;
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165
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166 static hashval_t
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167 hash (const sanopt_tree_couple &ref)
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168 {
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169 inchash::hash hstate (0);
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170 inchash::add_expr (ref.ptr, hstate);
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171 hstate.add_int (ref.pos_p);
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172 return hstate.end ();
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173 }
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174
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175 static bool
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176 equal (const sanopt_tree_couple &ref1, const sanopt_tree_couple &ref2)
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177 {
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178 return operand_equal_p (ref1.ptr, ref2.ptr, 0)
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179 && ref1.pos_p == ref2.pos_p;
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180 }
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181
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182 static void
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183 mark_deleted (sanopt_tree_couple &ref)
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184 {
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185 ref.ptr = reinterpret_cast<tree> (1);
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186 }
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187
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188 static void
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189 mark_empty (sanopt_tree_couple &ref)
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190 {
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191 ref.ptr = NULL;
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192 }
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193
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194 static bool
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195 is_deleted (const sanopt_tree_couple &ref)
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196 {
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197 return ref.ptr == reinterpret_cast<tree> (1);
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198 }
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199
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200 static bool
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201 is_empty (const sanopt_tree_couple &ref)
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202 {
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203 return ref.ptr == NULL;
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204 }
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205 };
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206
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207 /* This is used to carry various hash maps and variables used
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208 in sanopt_optimize_walker. */
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209
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210 struct sanopt_ctx
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211 {
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212 /* This map maps a pointer (the first argument of UBSAN_NULL) to
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213 a vector of UBSAN_NULL call statements that check this pointer. */
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214 hash_map<tree, auto_vec<gimple *> > null_check_map;
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215
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216 /* This map maps a pointer (the second argument of ASAN_CHECK) to
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217 a vector of ASAN_CHECK call statements that check the access. */
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218 hash_map<tree_operand_hash, auto_vec<gimple *> > asan_check_map;
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219
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220 /* This map maps a tree triplet (the first, second and fourth argument
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221 of UBSAN_VPTR) to a vector of UBSAN_VPTR call statements that check
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222 that virtual table pointer. */
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223 hash_map<sanopt_tree_triplet_hash, auto_vec<gimple *> > vptr_check_map;
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224
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225 /* This map maps a couple (tree and boolean) to a vector of UBSAN_PTR
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226 call statements that check that pointer overflow. */
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227 hash_map<sanopt_tree_couple_hash, auto_vec<gimple *> > ptr_check_map;
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228
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229 /* Number of IFN_ASAN_CHECK statements. */
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230 int asan_num_accesses;
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231
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232 /* True when the current functions constains an ASAN_MARK. */
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233 bool contains_asan_mark;
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234 };
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235
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236 /* Return true if there might be any call to free/munmap operation
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237 on any path in between DOM (which should be imm(BB)) and BB. */
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238
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239 static bool
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240 imm_dom_path_with_freeing_call (basic_block bb, basic_block dom)
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241 {
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242 sanopt_info *info = (sanopt_info *) bb->aux;
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243 edge e;
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244 edge_iterator ei;
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245
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246 if (info->imm_dom_path_with_freeing_call_computed_p)
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247 return info->imm_dom_path_with_freeing_call_p;
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248
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249 info->being_visited_p = true;
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250
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251 FOR_EACH_EDGE (e, ei, bb->preds)
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252 {
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253 sanopt_info *pred_info = (sanopt_info *) e->src->aux;
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254
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255 if (e->src == dom)
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256 continue;
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257
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258 if ((pred_info->imm_dom_path_with_freeing_call_computed_p
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259 && pred_info->imm_dom_path_with_freeing_call_p)
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260 || (pred_info->has_freeing_call_computed_p
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261 && pred_info->has_freeing_call_p))
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262 {
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263 info->imm_dom_path_with_freeing_call_computed_p = true;
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264 info->imm_dom_path_with_freeing_call_p = true;
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265 info->being_visited_p = false;
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266 return true;
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267 }
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268 }
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269
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270 FOR_EACH_EDGE (e, ei, bb->preds)
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271 {
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272 sanopt_info *pred_info = (sanopt_info *) e->src->aux;
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273
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274 if (e->src == dom)
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275 continue;
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276
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277 if (pred_info->has_freeing_call_computed_p)
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278 continue;
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279
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280 gimple_stmt_iterator gsi;
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281 for (gsi = gsi_start_bb (e->src); !gsi_end_p (gsi); gsi_next (&gsi))
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282 {
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283 gimple *stmt = gsi_stmt (gsi);
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284 gasm *asm_stmt;
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285
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286 if ((is_gimple_call (stmt) && !nonfreeing_call_p (stmt))
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287 || ((asm_stmt = dyn_cast <gasm *> (stmt))
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288 && (gimple_asm_clobbers_memory_p (asm_stmt)
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289 || gimple_asm_volatile_p (asm_stmt))))
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290 {
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291 pred_info->has_freeing_call_p = true;
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292 break;
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293 }
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294 }
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295
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296 pred_info->has_freeing_call_computed_p = true;
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297 if (pred_info->has_freeing_call_p)
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298 {
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299 info->imm_dom_path_with_freeing_call_computed_p = true;
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300 info->imm_dom_path_with_freeing_call_p = true;
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301 info->being_visited_p = false;
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302 return true;
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303 }
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304 }
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305
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306 FOR_EACH_EDGE (e, ei, bb->preds)
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307 {
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308 if (e->src == dom)
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309 continue;
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310
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311 basic_block src;
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312 for (src = e->src; src != dom; )
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313 {
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314 sanopt_info *pred_info = (sanopt_info *) src->aux;
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315 if (pred_info->being_visited_p)
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316 break;
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317 basic_block imm = get_immediate_dominator (CDI_DOMINATORS, src);
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318 if (imm_dom_path_with_freeing_call (src, imm))
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319 {
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320 info->imm_dom_path_with_freeing_call_computed_p = true;
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321 info->imm_dom_path_with_freeing_call_p = true;
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322 info->being_visited_p = false;
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323 return true;
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324 }
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325 src = imm;
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326 }
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327 }
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328
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329 info->imm_dom_path_with_freeing_call_computed_p = true;
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330 info->imm_dom_path_with_freeing_call_p = false;
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331 info->being_visited_p = false;
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332 return false;
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333 }
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334
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335 /* Get the first dominating check from the list of stored checks.
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336 Non-dominating checks are silently dropped. */
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337
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338 static gimple *
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339 maybe_get_dominating_check (auto_vec<gimple *> &v)
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340 {
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341 for (; !v.is_empty (); v.pop ())
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342 {
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343 gimple *g = v.last ();
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344 sanopt_info *si = (sanopt_info *) gimple_bb (g)->aux;
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345 if (!si->visited_p)
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346 /* At this point we shouldn't have any statements
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347 that aren't dominating the current BB. */
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348 return g;
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349 }
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350 return NULL;
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351 }
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352
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353 /* Optimize away redundant UBSAN_NULL calls. */
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354
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355 static bool
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356 maybe_optimize_ubsan_null_ifn (struct sanopt_ctx *ctx, gimple *stmt)
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357 {
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358 gcc_assert (gimple_call_num_args (stmt) == 3);
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359 tree ptr = gimple_call_arg (stmt, 0);
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360 tree cur_align = gimple_call_arg (stmt, 2);
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361 gcc_assert (TREE_CODE (cur_align) == INTEGER_CST);
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362 bool remove = false;
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363
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364 auto_vec<gimple *> &v = ctx->null_check_map.get_or_insert (ptr);
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365 gimple *g = maybe_get_dominating_check (v);
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366 if (!g)
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367 {
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368 /* For this PTR we don't have any UBSAN_NULL stmts recorded, so there's
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369 nothing to optimize yet. */
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370 v.safe_push (stmt);
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371 return false;
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372 }
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373
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374 /* We already have recorded a UBSAN_NULL check for this pointer. Perhaps we
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375 can drop this one. But only if this check doesn't specify stricter
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376 alignment. */
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377
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378 tree align = gimple_call_arg (g, 2);
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379 int kind = tree_to_shwi (gimple_call_arg (g, 1));
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380 /* If this is a NULL pointer check where we had segv anyway, we can
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381 remove it. */
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382 if (integer_zerop (align)
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383 && (kind == UBSAN_LOAD_OF
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384 || kind == UBSAN_STORE_OF
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385 || kind == UBSAN_MEMBER_ACCESS))
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386 remove = true;
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387 /* Otherwise remove the check in non-recovering mode, or if the
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388 stmts have same location. */
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389 else if (integer_zerop (align))
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390 remove = (flag_sanitize_recover & SANITIZE_NULL) == 0
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391 || flag_sanitize_undefined_trap_on_error
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392 || gimple_location (g) == gimple_location (stmt);
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393 else if (tree_int_cst_le (cur_align, align))
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394 remove = (flag_sanitize_recover & SANITIZE_ALIGNMENT) == 0
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395 || flag_sanitize_undefined_trap_on_error
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396 || gimple_location (g) == gimple_location (stmt);
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397
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398 if (!remove && gimple_bb (g) == gimple_bb (stmt)
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399 && tree_int_cst_compare (cur_align, align) == 0)
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|
|
400 v.pop ();
|
|
|
401
|
|
|
402 if (!remove)
|
|
|
403 v.safe_push (stmt);
|
|
|
404 return remove;
|
|
|
405 }
|
|
|
406
|
|
|
407 /* Return true when pointer PTR for a given CUR_OFFSET is already sanitized
|
|
|
408 in a given sanitization context CTX. */
|
|
|
409
|
|
|
410 static bool
|
|
|
411 has_dominating_ubsan_ptr_check (sanopt_ctx *ctx, tree ptr,
|
|
|
412 offset_int &cur_offset)
|
|
|
413 {
|
|
|
414 bool pos_p = !wi::neg_p (cur_offset);
|
|
|
415 sanopt_tree_couple couple;
|
|
|
416 couple.ptr = ptr;
|
|
|
417 couple.pos_p = pos_p;
|
|
|
418
|
|
|
419 auto_vec<gimple *> &v = ctx->ptr_check_map.get_or_insert (couple);
|
|
|
420 gimple *g = maybe_get_dominating_check (v);
|
|
|
421 if (!g)
|
|
|
422 return false;
|
|
|
423
|
|
|
424 /* We already have recorded a UBSAN_PTR check for this pointer. Perhaps we
|
|
|
425 can drop this one. But only if this check doesn't specify larger offset.
|
|
|
426 */
|
|
|
427 tree offset = gimple_call_arg (g, 1);
|
|
|
428 gcc_assert (TREE_CODE (offset) == INTEGER_CST);
|
|
|
429 offset_int ooffset = wi::sext (wi::to_offset (offset), POINTER_SIZE);
|
|
|
430
|
|
|
431 if (pos_p)
|
|
|
432 {
|
|
|
433 if (wi::les_p (cur_offset, ooffset))
|
|
|
434 return true;
|
|
|
435 }
|
|
|
436 else if (!pos_p && wi::les_p (ooffset, cur_offset))
|
|
|
437 return true;
|
|
|
438
|
|
|
439 return false;
|
|
|
440 }
|
|
|
441
|
|
|
442 /* Record UBSAN_PTR check of given context CTX. Register pointer PTR on
|
|
|
443 a given OFFSET that it's handled by GIMPLE STMT. */
|
|
|
444
|
|
|
445 static void
|
|
|
446 record_ubsan_ptr_check_stmt (sanopt_ctx *ctx, gimple *stmt, tree ptr,
|
|
|
447 const offset_int &offset)
|
|
|
448 {
|
|
|
449 sanopt_tree_couple couple;
|
|
|
450 couple.ptr = ptr;
|
|
|
451 couple.pos_p = !wi::neg_p (offset);
|
|
|
452
|
|
|
453 auto_vec<gimple *> &v = ctx->ptr_check_map.get_or_insert (couple);
|
|
|
454 v.safe_push (stmt);
|
|
|
455 }
|
|
|
456
|
|
|
457 /* Optimize away redundant UBSAN_PTR calls. */
|
|
|
458
|
|
|
459 static bool
|
|
|
460 maybe_optimize_ubsan_ptr_ifn (sanopt_ctx *ctx, gimple *stmt)
|
|
|
461 {
|
|
131
|
462 poly_int64 bitsize, pbitpos;
|
|
111
|
463 machine_mode mode;
|
|
|
464 int volatilep = 0, reversep, unsignedp = 0;
|
|
|
465 tree offset;
|
|
|
466
|
|
|
467 gcc_assert (gimple_call_num_args (stmt) == 2);
|
|
|
468 tree ptr = gimple_call_arg (stmt, 0);
|
|
|
469 tree off = gimple_call_arg (stmt, 1);
|
|
|
470
|
|
|
471 if (TREE_CODE (off) != INTEGER_CST)
|
|
|
472 return false;
|
|
|
473
|
|
|
474 if (integer_zerop (off))
|
|
|
475 return true;
|
|
|
476
|
|
|
477 offset_int cur_offset = wi::sext (wi::to_offset (off), POINTER_SIZE);
|
|
|
478 if (has_dominating_ubsan_ptr_check (ctx, ptr, cur_offset))
|
|
|
479 return true;
|
|
|
480
|
|
|
481 tree base = ptr;
|
|
|
482 if (TREE_CODE (base) == ADDR_EXPR)
|
|
|
483 {
|
|
|
484 base = TREE_OPERAND (base, 0);
|
|
|
485
|
|
131
|
486 HOST_WIDE_INT bitpos;
|
|
|
487 base = get_inner_reference (base, &bitsize, &pbitpos, &offset, &mode,
|
|
111
|
488 &unsignedp, &reversep, &volatilep);
|
|
131
|
489 if ((offset == NULL_TREE || TREE_CODE (offset) == INTEGER_CST)
|
|
|
490 && DECL_P (base)
|
|
|
491 && !DECL_REGISTER (base)
|
|
|
492 && pbitpos.is_constant (&bitpos))
|
|
111
|
493 {
|
|
131
|
494 offset_int expr_offset;
|
|
|
495 if (offset)
|
|
|
496 expr_offset = wi::to_offset (offset) + bitpos / BITS_PER_UNIT;
|
|
|
497 else
|
|
|
498 expr_offset = bitpos / BITS_PER_UNIT;
|
|
|
499 expr_offset = wi::sext (expr_offset, POINTER_SIZE);
|
|
111
|
500 offset_int total_offset = expr_offset + cur_offset;
|
|
|
501 if (total_offset != wi::sext (total_offset, POINTER_SIZE))
|
|
|
502 {
|
|
|
503 record_ubsan_ptr_check_stmt (ctx, stmt, ptr, cur_offset);
|
|
|
504 return false;
|
|
|
505 }
|
|
|
506
|
|
|
507 /* If BASE is a fixed size automatic variable or
|
|
|
508 global variable defined in the current TU, we don't have
|
|
|
509 to instrument anything if offset is within address
|
|
|
510 of the variable. */
|
|
|
511 if ((VAR_P (base)
|
|
|
512 || TREE_CODE (base) == PARM_DECL
|
|
|
513 || TREE_CODE (base) == RESULT_DECL)
|
|
|
514 && DECL_SIZE_UNIT (base)
|
|
|
515 && TREE_CODE (DECL_SIZE_UNIT (base)) == INTEGER_CST
|
|
|
516 && (!is_global_var (base) || decl_binds_to_current_def_p (base)))
|
|
|
517 {
|
|
|
518 offset_int base_size = wi::to_offset (DECL_SIZE_UNIT (base));
|
|
131
|
519 if (!wi::neg_p (expr_offset)
|
|
111
|
520 && wi::les_p (total_offset, base_size))
|
|
|
521 {
|
|
|
522 if (!wi::neg_p (total_offset)
|
|
|
523 && wi::les_p (total_offset, base_size))
|
|
|
524 return true;
|
|
|
525 }
|
|
|
526 }
|
|
|
527
|
|
|
528 /* Following expression: UBSAN_PTR (&MEM_REF[ptr + x], y) can be
|
|
|
529 handled as follows:
|
|
|
530
|
|
|
531 1) sign (x) == sign (y), then check for dominating check of (x + y)
|
|
|
532 2) sign (x) != sign (y), then first check if we have a dominating
|
|
|
533 check for ptr + x. If so, then we have 2 situations:
|
|
|
534 a) sign (x) == sign (x + y), here we are done, example:
|
|
|
535 UBSAN_PTR (&MEM_REF[ptr + 100], -50)
|
|
|
536 b) check for dominating check of ptr + x + y.
|
|
|
537 */
|
|
|
538
|
|
|
539 bool sign_cur_offset = !wi::neg_p (cur_offset);
|
|
131
|
540 bool sign_expr_offset = !wi::neg_p (expr_offset);
|
|
111
|
541
|
|
|
542 tree base_addr
|
|
|
543 = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (base)), base);
|
|
|
544
|
|
|
545 bool add = false;
|
|
|
546 if (sign_cur_offset == sign_expr_offset)
|
|
|
547 {
|
|
|
548 if (has_dominating_ubsan_ptr_check (ctx, base_addr, total_offset))
|
|
|
549 return true;
|
|
|
550 else
|
|
|
551 add = true;
|
|
|
552 }
|
|
|
553 else
|
|
|
554 {
|
|
|
555 if (!has_dominating_ubsan_ptr_check (ctx, base_addr, expr_offset))
|
|
|
556 ; /* Don't record base_addr + expr_offset, it's not a guarding
|
|
|
557 check. */
|
|
|
558 else
|
|
|
559 {
|
|
|
560 bool sign_total_offset = !wi::neg_p (total_offset);
|
|
|
561 if (sign_expr_offset == sign_total_offset)
|
|
|
562 return true;
|
|
|
563 else
|
|
|
564 {
|
|
|
565 if (has_dominating_ubsan_ptr_check (ctx, base_addr,
|
|
|
566 total_offset))
|
|
|
567 return true;
|
|
|
568 else
|
|
|
569 add = true;
|
|
|
570 }
|
|
|
571 }
|
|
|
572 }
|
|
|
573
|
|
|
574 /* Record a new dominating check for base_addr + total_offset. */
|
|
|
575 if (add && !operand_equal_p (base, base_addr, 0))
|
|
|
576 record_ubsan_ptr_check_stmt (ctx, stmt, base_addr,
|
|
|
577 total_offset);
|
|
|
578 }
|
|
|
579 }
|
|
|
580
|
|
|
581 /* For this PTR we don't have any UBSAN_PTR stmts recorded, so there's
|
|
|
582 nothing to optimize yet. */
|
|
|
583 record_ubsan_ptr_check_stmt (ctx, stmt, ptr, cur_offset);
|
|
|
584
|
|
|
585 return false;
|
|
|
586 }
|
|
|
587
|
|
|
588 /* Optimize away redundant UBSAN_VPTR calls. The second argument
|
|
|
589 is the value loaded from the virtual table, so rely on FRE to find out
|
|
|
590 when we can actually optimize. */
|
|
|
591
|
|
|
592 static bool
|
|
|
593 maybe_optimize_ubsan_vptr_ifn (struct sanopt_ctx *ctx, gimple *stmt)
|
|
|
594 {
|
|
|
595 gcc_assert (gimple_call_num_args (stmt) == 5);
|
|
|
596 sanopt_tree_triplet triplet;
|
|
|
597 triplet.t1 = gimple_call_arg (stmt, 0);
|
|
|
598 triplet.t2 = gimple_call_arg (stmt, 1);
|
|
|
599 triplet.t3 = gimple_call_arg (stmt, 3);
|
|
|
600
|
|
|
601 auto_vec<gimple *> &v = ctx->vptr_check_map.get_or_insert (triplet);
|
|
|
602 gimple *g = maybe_get_dominating_check (v);
|
|
|
603 if (!g)
|
|
|
604 {
|
|
|
605 /* For this PTR we don't have any UBSAN_VPTR stmts recorded, so there's
|
|
|
606 nothing to optimize yet. */
|
|
|
607 v.safe_push (stmt);
|
|
|
608 return false;
|
|
|
609 }
|
|
|
610
|
|
|
611 return true;
|
|
|
612 }
|
|
|
613
|
|
|
614 /* Returns TRUE if ASan check of length LEN in block BB can be removed
|
|
|
615 if preceded by checks in V. */
|
|
|
616
|
|
|
617 static bool
|
|
|
618 can_remove_asan_check (auto_vec<gimple *> &v, tree len, basic_block bb)
|
|
|
619 {
|
|
|
620 unsigned int i;
|
|
|
621 gimple *g;
|
|
|
622 gimple *to_pop = NULL;
|
|
|
623 bool remove = false;
|
|
|
624 basic_block last_bb = bb;
|
|
|
625 bool cleanup = false;
|
|
|
626
|
|
|
627 FOR_EACH_VEC_ELT_REVERSE (v, i, g)
|
|
|
628 {
|
|
|
629 basic_block gbb = gimple_bb (g);
|
|
|
630 sanopt_info *si = (sanopt_info *) gbb->aux;
|
|
|
631 if (gimple_uid (g) < si->freeing_call_events)
|
|
|
632 {
|
|
|
633 /* If there is a potentially freeing call after g in gbb, we should
|
|
|
634 remove it from the vector, can't use in optimization. */
|
|
|
635 cleanup = true;
|
|
|
636 continue;
|
|
|
637 }
|
|
|
638
|
|
|
639 tree glen = gimple_call_arg (g, 2);
|
|
|
640 gcc_assert (TREE_CODE (glen) == INTEGER_CST);
|
|
|
641
|
|
|
642 /* If we've checked only smaller length than we want to check now,
|
|
|
643 we can't remove the current stmt. If g is in the same basic block,
|
|
|
644 we want to remove it though, as the current stmt is better. */
|
|
|
645 if (tree_int_cst_lt (glen, len))
|
|
|
646 {
|
|
|
647 if (gbb == bb)
|
|
|
648 {
|
|
|
649 to_pop = g;
|
|
|
650 cleanup = true;
|
|
|
651 }
|
|
|
652 continue;
|
|
|
653 }
|
|
|
654
|
|
|
655 while (last_bb != gbb)
|
|
|
656 {
|
|
|
657 /* Paths from last_bb to bb have been checked before.
|
|
|
658 gbb is necessarily a dominator of last_bb, but not necessarily
|
|
|
659 immediate dominator. */
|
|
|
660 if (((sanopt_info *) last_bb->aux)->freeing_call_events)
|
|
|
661 break;
|
|
|
662
|
|
|
663 basic_block imm = get_immediate_dominator (CDI_DOMINATORS, last_bb);
|
|
|
664 gcc_assert (imm);
|
|
|
665 if (imm_dom_path_with_freeing_call (last_bb, imm))
|
|
|
666 break;
|
|
|
667
|
|
|
668 last_bb = imm;
|
|
|
669 }
|
|
|
670 if (last_bb == gbb)
|
|
|
671 remove = true;
|
|
|
672 break;
|
|
|
673 }
|
|
|
674
|
|
|
675 if (cleanup)
|
|
|
676 {
|
|
|
677 unsigned int j = 0, l = v.length ();
|
|
|
678 for (i = 0; i < l; i++)
|
|
|
679 if (v[i] != to_pop
|
|
|
680 && (gimple_uid (v[i])
|
|
|
681 == ((sanopt_info *)
|
|
|
682 gimple_bb (v[i])->aux)->freeing_call_events))
|
|
|
683 {
|
|
|
684 if (i != j)
|
|
|
685 v[j] = v[i];
|
|
|
686 j++;
|
|
|
687 }
|
|
|
688 v.truncate (j);
|
|
|
689 }
|
|
|
690
|
|
|
691 return remove;
|
|
|
692 }
|
|
|
693
|
|
|
694 /* Optimize away redundant ASAN_CHECK calls. */
|
|
|
695
|
|
|
696 static bool
|
|
|
697 maybe_optimize_asan_check_ifn (struct sanopt_ctx *ctx, gimple *stmt)
|
|
|
698 {
|
|
|
699 gcc_assert (gimple_call_num_args (stmt) == 4);
|
|
|
700 tree ptr = gimple_call_arg (stmt, 1);
|
|
|
701 tree len = gimple_call_arg (stmt, 2);
|
|
|
702 basic_block bb = gimple_bb (stmt);
|
|
|
703 sanopt_info *info = (sanopt_info *) bb->aux;
|
|
|
704
|
|
|
705 if (TREE_CODE (len) != INTEGER_CST)
|
|
|
706 return false;
|
|
|
707 if (integer_zerop (len))
|
|
|
708 return false;
|
|
|
709
|
|
|
710 gimple_set_uid (stmt, info->freeing_call_events);
|
|
|
711
|
|
|
712 auto_vec<gimple *> *ptr_checks = &ctx->asan_check_map.get_or_insert (ptr);
|
|
|
713
|
|
|
714 tree base_addr = maybe_get_single_definition (ptr);
|
|
|
715 auto_vec<gimple *> *base_checks = NULL;
|
|
|
716 if (base_addr)
|
|
|
717 {
|
|
|
718 base_checks = &ctx->asan_check_map.get_or_insert (base_addr);
|
|
|
719 /* Original pointer might have been invalidated. */
|
|
|
720 ptr_checks = ctx->asan_check_map.get (ptr);
|
|
|
721 }
|
|
|
722
|
|
|
723 gimple *g = maybe_get_dominating_check (*ptr_checks);
|
|
|
724 gimple *g2 = NULL;
|
|
|
725
|
|
|
726 if (base_checks)
|
|
|
727 /* Try with base address as well. */
|
|
|
728 g2 = maybe_get_dominating_check (*base_checks);
|
|
|
729
|
|
|
730 if (g == NULL && g2 == NULL)
|
|
|
731 {
|
|
|
732 /* For this PTR we don't have any ASAN_CHECK stmts recorded, so there's
|
|
|
733 nothing to optimize yet. */
|
|
|
734 ptr_checks->safe_push (stmt);
|
|
|
735 if (base_checks)
|
|
|
736 base_checks->safe_push (stmt);
|
|
|
737 return false;
|
|
|
738 }
|
|
|
739
|
|
|
740 bool remove = false;
|
|
|
741
|
|
|
742 if (ptr_checks)
|
|
|
743 remove = can_remove_asan_check (*ptr_checks, len, bb);
|
|
|
744
|
|
|
745 if (!remove && base_checks)
|
|
|
746 /* Try with base address as well. */
|
|
|
747 remove = can_remove_asan_check (*base_checks, len, bb);
|
|
|
748
|
|
|
749 if (!remove)
|
|
|
750 {
|
|
|
751 ptr_checks->safe_push (stmt);
|
|
|
752 if (base_checks)
|
|
|
753 base_checks->safe_push (stmt);
|
|
|
754 }
|
|
|
755
|
|
|
756 return remove;
|
|
|
757 }
|
|
|
758
|
|
|
759 /* Try to optimize away redundant UBSAN_NULL and ASAN_CHECK calls.
|
|
|
760
|
|
|
761 We walk blocks in the CFG via a depth first search of the dominator
|
|
|
762 tree; we push unique UBSAN_NULL or ASAN_CHECK statements into a vector
|
|
|
763 in the NULL_CHECK_MAP or ASAN_CHECK_MAP hash maps as we enter the
|
|
|
764 blocks. When leaving a block, we mark the block as visited; then
|
|
|
765 when checking the statements in the vector, we ignore statements that
|
|
|
766 are coming from already visited blocks, because these cannot dominate
|
|
|
767 anything anymore. CTX is a sanopt context. */
|
|
|
768
|
|
|
769 static void
|
|
|
770 sanopt_optimize_walker (basic_block bb, struct sanopt_ctx *ctx)
|
|
|
771 {
|
|
|
772 basic_block son;
|
|
|
773 gimple_stmt_iterator gsi;
|
|
|
774 sanopt_info *info = (sanopt_info *) bb->aux;
|
|
|
775 bool asan_check_optimize = (flag_sanitize & SANITIZE_ADDRESS) != 0;
|
|
|
776
|
|
|
777 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
|
|
|
778 {
|
|
|
779 gimple *stmt = gsi_stmt (gsi);
|
|
|
780 bool remove = false;
|
|
|
781
|
|
|
782 if (!is_gimple_call (stmt))
|
|
|
783 {
|
|
|
784 /* Handle asm volatile or asm with "memory" clobber
|
|
|
785 the same as potentionally freeing call. */
|
|
|
786 gasm *asm_stmt = dyn_cast <gasm *> (stmt);
|
|
|
787 if (asm_stmt
|
|
|
788 && asan_check_optimize
|
|
|
789 && (gimple_asm_clobbers_memory_p (asm_stmt)
|
|
|
790 || gimple_asm_volatile_p (asm_stmt)))
|
|
|
791 info->freeing_call_events++;
|
|
|
792 gsi_next (&gsi);
|
|
|
793 continue;
|
|
|
794 }
|
|
|
795
|
|
|
796 if (asan_check_optimize && !nonfreeing_call_p (stmt))
|
|
|
797 info->freeing_call_events++;
|
|
|
798
|
|
|
799 /* If __asan_before_dynamic_init ("module"); is followed by
|
|
|
800 __asan_after_dynamic_init (); without intervening memory loads/stores,
|
|
|
801 there is nothing to guard, so optimize both away. */
|
|
|
802 if (asan_check_optimize
|
|
|
803 && gimple_call_builtin_p (stmt, BUILT_IN_ASAN_BEFORE_DYNAMIC_INIT))
|
|
|
804 {
|
|
|
805 use_operand_p use;
|
|
|
806 gimple *use_stmt;
|
|
|
807 if (single_imm_use (gimple_vdef (stmt), &use, &use_stmt))
|
|
|
808 {
|
|
|
809 if (is_gimple_call (use_stmt)
|
|
|
810 && gimple_call_builtin_p (use_stmt,
|
|
|
811 BUILT_IN_ASAN_AFTER_DYNAMIC_INIT))
|
|
|
812 {
|
|
|
813 unlink_stmt_vdef (use_stmt);
|
|
|
814 gimple_stmt_iterator gsi2 = gsi_for_stmt (use_stmt);
|
|
|
815 gsi_remove (&gsi2, true);
|
|
|
816 remove = true;
|
|
|
817 }
|
|
|
818 }
|
|
|
819 }
|
|
|
820
|
|
|
821 if (gimple_call_internal_p (stmt))
|
|
|
822 switch (gimple_call_internal_fn (stmt))
|
|
|
823 {
|
|
|
824 case IFN_UBSAN_NULL:
|
|
|
825 remove = maybe_optimize_ubsan_null_ifn (ctx, stmt);
|
|
|
826 break;
|
|
|
827 case IFN_UBSAN_VPTR:
|
|
|
828 remove = maybe_optimize_ubsan_vptr_ifn (ctx, stmt);
|
|
|
829 break;
|
|
|
830 case IFN_UBSAN_PTR:
|
|
|
831 remove = maybe_optimize_ubsan_ptr_ifn (ctx, stmt);
|
|
|
832 break;
|
|
|
833 case IFN_ASAN_CHECK:
|
|
|
834 if (asan_check_optimize)
|
|
|
835 remove = maybe_optimize_asan_check_ifn (ctx, stmt);
|
|
|
836 if (!remove)
|
|
|
837 ctx->asan_num_accesses++;
|
|
|
838 break;
|
|
|
839 case IFN_ASAN_MARK:
|
|
|
840 ctx->contains_asan_mark = true;
|
|
|
841 break;
|
|
|
842 default:
|
|
|
843 break;
|
|
|
844 }
|
|
|
845
|
|
|
846 if (remove)
|
|
|
847 {
|
|
|
848 /* Drop this check. */
|
|
|
849 if (dump_file && (dump_flags & TDF_DETAILS))
|
|
|
850 {
|
|
|
851 fprintf (dump_file, "Optimizing out: ");
|
|
|
852 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
|
|
|
853 }
|
|
|
854 unlink_stmt_vdef (stmt);
|
|
|
855 gsi_remove (&gsi, true);
|
|
|
856 }
|
|
|
857 else
|
|
|
858 {
|
|
|
859 if (dump_file && (dump_flags & TDF_DETAILS))
|
|
|
860 {
|
|
|
861 fprintf (dump_file, "Leaving: ");
|
|
|
862 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
|
|
|
863 }
|
|
|
864
|
|
|
865 gsi_next (&gsi);
|
|
|
866 }
|
|
|
867 }
|
|
|
868
|
|
|
869 if (asan_check_optimize)
|
|
|
870 {
|
|
|
871 info->has_freeing_call_p = info->freeing_call_events != 0;
|
|
|
872 info->has_freeing_call_computed_p = true;
|
|
|
873 }
|
|
|
874
|
|
|
875 for (son = first_dom_son (CDI_DOMINATORS, bb);
|
|
|
876 son;
|
|
|
877 son = next_dom_son (CDI_DOMINATORS, son))
|
|
|
878 sanopt_optimize_walker (son, ctx);
|
|
|
879
|
|
|
880 /* We're leaving this BB, so mark it to that effect. */
|
|
|
881 info->visited_p = true;
|
|
|
882 }
|
|
|
883
|
|
|
884 /* Try to remove redundant sanitizer checks in function FUN. */
|
|
|
885
|
|
|
886 static int
|
|
|
887 sanopt_optimize (function *fun, bool *contains_asan_mark)
|
|
|
888 {
|
|
|
889 struct sanopt_ctx ctx;
|
|
|
890 ctx.asan_num_accesses = 0;
|
|
|
891 ctx.contains_asan_mark = false;
|
|
|
892
|
|
|
893 /* Set up block info for each basic block. */
|
|
|
894 alloc_aux_for_blocks (sizeof (sanopt_info));
|
|
|
895
|
|
|
896 /* We're going to do a dominator walk, so ensure that we have
|
|
|
897 dominance information. */
|
|
|
898 calculate_dominance_info (CDI_DOMINATORS);
|
|
|
899
|
|
|
900 /* Recursively walk the dominator tree optimizing away
|
|
|
901 redundant checks. */
|
|
|
902 sanopt_optimize_walker (ENTRY_BLOCK_PTR_FOR_FN (fun), &ctx);
|
|
|
903
|
|
|
904 free_aux_for_blocks ();
|
|
|
905
|
|
|
906 *contains_asan_mark = ctx.contains_asan_mark;
|
|
|
907 return ctx.asan_num_accesses;
|
|
|
908 }
|
|
|
909
|
|
|
910 /* Perform optimization of sanitize functions. */
|
|
|
911
|
|
|
912 namespace {
|
|
|
913
|
|
|
914 const pass_data pass_data_sanopt =
|
|
|
915 {
|
|
|
916 GIMPLE_PASS, /* type */
|
|
|
917 "sanopt", /* name */
|
|
|
918 OPTGROUP_NONE, /* optinfo_flags */
|
|
|
919 TV_NONE, /* tv_id */
|
|
|
920 ( PROP_ssa | PROP_cfg | PROP_gimple_leh ), /* properties_required */
|
|
|
921 0, /* properties_provided */
|
|
|
922 0, /* properties_destroyed */
|
|
|
923 0, /* todo_flags_start */
|
|
|
924 TODO_update_ssa, /* todo_flags_finish */
|
|
|
925 };
|
|
|
926
|
|
|
927 class pass_sanopt : public gimple_opt_pass
|
|
|
928 {
|
|
|
929 public:
|
|
|
930 pass_sanopt (gcc::context *ctxt)
|
|
|
931 : gimple_opt_pass (pass_data_sanopt, ctxt)
|
|
|
932 {}
|
|
|
933
|
|
|
934 /* opt_pass methods: */
|
|
|
935 virtual bool gate (function *) { return flag_sanitize; }
|
|
|
936 virtual unsigned int execute (function *);
|
|
|
937
|
|
|
938 }; // class pass_sanopt
|
|
|
939
|
|
|
940 /* Sanitize all ASAN_MARK unpoison calls that are not reachable by a BB
|
|
|
941 that contains an ASAN_MARK poison. All these ASAN_MARK unpoison call
|
|
|
942 can be removed as all variables are unpoisoned in a function prologue. */
|
|
|
943
|
|
|
944 static void
|
|
|
945 sanitize_asan_mark_unpoison (void)
|
|
|
946 {
|
|
|
947 /* 1) Find all BBs that contain an ASAN_MARK poison call. */
|
|
|
948 auto_sbitmap with_poison (last_basic_block_for_fn (cfun) + 1);
|
|
|
949 bitmap_clear (with_poison);
|
|
|
950 basic_block bb;
|
|
|
951
|
|
|
952 FOR_EACH_BB_FN (bb, cfun)
|
|
|
953 {
|
|
|
954 if (bitmap_bit_p (with_poison, bb->index))
|
|
|
955 continue;
|
|
|
956
|
|
|
957 gimple_stmt_iterator gsi;
|
|
|
958 for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi))
|
|
|
959 {
|
|
|
960 gimple *stmt = gsi_stmt (gsi);
|
|
|
961 if (asan_mark_p (stmt, ASAN_MARK_POISON))
|
|
|
962 {
|
|
|
963 bitmap_set_bit (with_poison, bb->index);
|
|
|
964 break;
|
|
|
965 }
|
|
|
966 }
|
|
|
967 }
|
|
|
968
|
|
|
969 auto_sbitmap poisoned (last_basic_block_for_fn (cfun) + 1);
|
|
|
970 bitmap_clear (poisoned);
|
|
|
971 auto_sbitmap worklist (last_basic_block_for_fn (cfun) + 1);
|
|
|
972 bitmap_copy (worklist, with_poison);
|
|
|
973
|
|
|
974 /* 2) Propagate the information to all reachable blocks. */
|
|
|
975 while (!bitmap_empty_p (worklist))
|
|
|
976 {
|
|
|
977 unsigned i = bitmap_first_set_bit (worklist);
|
|
|
978 bitmap_clear_bit (worklist, i);
|
|
|
979 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i);
|
|
|
980 gcc_assert (bb);
|
|
|
981
|
|
|
982 edge e;
|
|
|
983 edge_iterator ei;
|
|
|
984 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
985 if (!bitmap_bit_p (poisoned, e->dest->index))
|
|
|
986 {
|
|
|
987 bitmap_set_bit (poisoned, e->dest->index);
|
|
|
988 bitmap_set_bit (worklist, e->dest->index);
|
|
|
989 }
|
|
|
990 }
|
|
|
991
|
|
|
992 /* 3) Iterate all BBs not included in POISONED BBs and remove unpoison
|
|
|
993 ASAN_MARK preceding an ASAN_MARK poison (which can still happen). */
|
|
|
994 FOR_EACH_BB_FN (bb, cfun)
|
|
|
995 {
|
|
|
996 if (bitmap_bit_p (poisoned, bb->index))
|
|
|
997 continue;
|
|
|
998
|
|
|
999 gimple_stmt_iterator gsi;
|
|
|
1000 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
|
|
|
1001 {
|
|
|
1002 gimple *stmt = gsi_stmt (gsi);
|
|
|
1003 if (gimple_call_internal_p (stmt, IFN_ASAN_MARK))
|
|
|
1004 {
|
|
|
1005 if (asan_mark_p (stmt, ASAN_MARK_POISON))
|
|
|
1006 break;
|
|
|
1007 else
|
|
|
1008 {
|
|
|
1009 if (dump_file)
|
|
|
1010 fprintf (dump_file, "Removing ASAN_MARK unpoison\n");
|
|
|
1011 unlink_stmt_vdef (stmt);
|
|
|
1012 release_defs (stmt);
|
|
|
1013 gsi_remove (&gsi, true);
|
|
|
1014 continue;
|
|
|
1015 }
|
|
|
1016 }
|
|
|
1017
|
|
|
1018 gsi_next (&gsi);
|
|
|
1019 }
|
|
|
1020 }
|
|
|
1021 }
|
|
|
1022
|
|
|
1023 /* Return true when STMT is either ASAN_CHECK call or a call of a function
|
|
|
1024 that can contain an ASAN_CHECK. */
|
|
|
1025
|
|
|
1026 static bool
|
|
|
1027 maybe_contains_asan_check (gimple *stmt)
|
|
|
1028 {
|
|
|
1029 if (is_gimple_call (stmt))
|
|
|
1030 {
|
|
|
1031 if (gimple_call_internal_p (stmt, IFN_ASAN_MARK))
|
|
|
1032 return false;
|
|
|
1033 else
|
|
|
1034 return !(gimple_call_flags (stmt) & ECF_CONST);
|
|
|
1035 }
|
|
|
1036 else if (is_a<gasm *> (stmt))
|
|
|
1037 return true;
|
|
|
1038
|
|
|
1039 return false;
|
|
|
1040 }
|
|
|
1041
|
|
|
1042 /* Sanitize all ASAN_MARK poison calls that are not followed by an ASAN_CHECK
|
|
|
1043 call. These calls can be removed. */
|
|
|
1044
|
|
|
1045 static void
|
|
|
1046 sanitize_asan_mark_poison (void)
|
|
|
1047 {
|
|
|
1048 /* 1) Find all BBs that possibly contain an ASAN_CHECK. */
|
|
|
1049 auto_sbitmap with_check (last_basic_block_for_fn (cfun) + 1);
|
|
|
1050 bitmap_clear (with_check);
|
|
|
1051 basic_block bb;
|
|
|
1052
|
|
|
1053 FOR_EACH_BB_FN (bb, cfun)
|
|
|
1054 {
|
|
|
1055 gimple_stmt_iterator gsi;
|
|
|
1056 for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi))
|
|
|
1057 {
|
|
|
1058 gimple *stmt = gsi_stmt (gsi);
|
|
|
1059 if (maybe_contains_asan_check (stmt))
|
|
|
1060 {
|
|
|
1061 bitmap_set_bit (with_check, bb->index);
|
|
|
1062 break;
|
|
|
1063 }
|
|
|
1064 }
|
|
|
1065 }
|
|
|
1066
|
|
|
1067 auto_sbitmap can_reach_check (last_basic_block_for_fn (cfun) + 1);
|
|
|
1068 bitmap_clear (can_reach_check);
|
|
|
1069 auto_sbitmap worklist (last_basic_block_for_fn (cfun) + 1);
|
|
|
1070 bitmap_copy (worklist, with_check);
|
|
|
1071
|
|
|
1072 /* 2) Propagate the information to all definitions blocks. */
|
|
|
1073 while (!bitmap_empty_p (worklist))
|
|
|
1074 {
|
|
|
1075 unsigned i = bitmap_first_set_bit (worklist);
|
|
|
1076 bitmap_clear_bit (worklist, i);
|
|
|
1077 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i);
|
|
|
1078 gcc_assert (bb);
|
|
|
1079
|
|
|
1080 edge e;
|
|
|
1081 edge_iterator ei;
|
|
|
1082 FOR_EACH_EDGE (e, ei, bb->preds)
|
|
|
1083 if (!bitmap_bit_p (can_reach_check, e->src->index))
|
|
|
1084 {
|
|
|
1085 bitmap_set_bit (can_reach_check, e->src->index);
|
|
|
1086 bitmap_set_bit (worklist, e->src->index);
|
|
|
1087 }
|
|
|
1088 }
|
|
|
1089
|
|
|
1090 /* 3) Iterate all BBs not included in CAN_REACH_CHECK BBs and remove poison
|
|
|
1091 ASAN_MARK not followed by a call to function having an ASAN_CHECK. */
|
|
|
1092 FOR_EACH_BB_FN (bb, cfun)
|
|
|
1093 {
|
|
|
1094 if (bitmap_bit_p (can_reach_check, bb->index))
|
|
|
1095 continue;
|
|
|
1096
|
|
|
1097 gimple_stmt_iterator gsi;
|
|
|
1098 for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);)
|
|
|
1099 {
|
|
|
1100 gimple *stmt = gsi_stmt (gsi);
|
|
|
1101 if (maybe_contains_asan_check (stmt))
|
|
|
1102 break;
|
|
|
1103 else if (asan_mark_p (stmt, ASAN_MARK_POISON))
|
|
|
1104 {
|
|
|
1105 if (dump_file)
|
|
|
1106 fprintf (dump_file, "Removing ASAN_MARK poison\n");
|
|
|
1107 unlink_stmt_vdef (stmt);
|
|
|
1108 release_defs (stmt);
|
|
|
1109 gimple_stmt_iterator gsi2 = gsi;
|
|
|
1110 gsi_prev (&gsi);
|
|
|
1111 gsi_remove (&gsi2, true);
|
|
|
1112 continue;
|
|
|
1113 }
|
|
|
1114
|
|
|
1115 gsi_prev (&gsi);
|
|
|
1116 }
|
|
|
1117 }
|
|
|
1118 }
|
|
|
1119
|
|
|
1120 /* Rewrite all usages of tree OP which is a PARM_DECL with a VAR_DECL
|
|
|
1121 that is it's DECL_VALUE_EXPR. */
|
|
|
1122
|
|
|
1123 static tree
|
|
|
1124 rewrite_usage_of_param (tree *op, int *walk_subtrees, void *)
|
|
|
1125 {
|
|
|
1126 if (TREE_CODE (*op) == PARM_DECL && DECL_HAS_VALUE_EXPR_P (*op))
|
|
|
1127 {
|
|
|
1128 *op = DECL_VALUE_EXPR (*op);
|
|
|
1129 *walk_subtrees = 0;
|
|
|
1130 }
|
|
|
1131
|
|
|
1132 return NULL;
|
|
|
1133 }
|
|
|
1134
|
|
|
1135 /* For a given function FUN, rewrite all addressable parameters so that
|
|
|
1136 a new automatic variable is introduced. Right after function entry
|
|
|
1137 a parameter is assigned to the variable. */
|
|
|
1138
|
|
|
1139 static void
|
|
|
1140 sanitize_rewrite_addressable_params (function *fun)
|
|
|
1141 {
|
|
|
1142 gimple *g;
|
|
|
1143 gimple_seq stmts = NULL;
|
|
|
1144 bool has_any_addressable_param = false;
|
|
|
1145 auto_vec<tree> clear_value_expr_list;
|
|
|
1146
|
|
|
1147 for (tree arg = DECL_ARGUMENTS (current_function_decl);
|
|
|
1148 arg; arg = DECL_CHAIN (arg))
|
|
|
1149 {
|
|
|
1150 tree type = TREE_TYPE (arg);
|
|
131
|
1151 if (TREE_ADDRESSABLE (arg)
|
|
|
1152 && !TREE_ADDRESSABLE (type)
|
|
|
1153 && !TREE_THIS_VOLATILE (arg)
|
|
111
|
1154 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
|
|
|
1155 {
|
|
|
1156 TREE_ADDRESSABLE (arg) = 0;
|
|
|
1157 /* The parameter is no longer addressable. */
|
|
|
1158 has_any_addressable_param = true;
|
|
|
1159
|
|
|
1160 /* Create a new automatic variable. */
|
|
|
1161 tree var = build_decl (DECL_SOURCE_LOCATION (arg),
|
|
|
1162 VAR_DECL, DECL_NAME (arg), type);
|
|
|
1163 TREE_ADDRESSABLE (var) = 1;
|
|
|
1164 DECL_IGNORED_P (var) = 1;
|
|
|
1165
|
|
|
1166 gimple_add_tmp_var (var);
|
|
|
1167
|
|
131
|
1168 /* We skip parameters that have a DECL_VALUE_EXPR. */
|
|
|
1169 if (DECL_HAS_VALUE_EXPR_P (arg))
|
|
|
1170 continue;
|
|
|
1171
|
|
111
|
1172 if (dump_file)
|
|
|
1173 fprintf (dump_file,
|
|
|
1174 "Rewriting parameter whose address is taken: %s\n",
|
|
|
1175 IDENTIFIER_POINTER (DECL_NAME (arg)));
|
|
|
1176
|
|
|
1177 SET_DECL_PT_UID (var, DECL_PT_UID (arg));
|
|
|
1178
|
|
|
1179 /* Assign value of parameter to newly created variable. */
|
|
|
1180 if ((TREE_CODE (type) == COMPLEX_TYPE
|
|
|
1181 || TREE_CODE (type) == VECTOR_TYPE))
|
|
|
1182 {
|
|
|
1183 /* We need to create a SSA name that will be used for the
|
|
|
1184 assignment. */
|
|
|
1185 DECL_GIMPLE_REG_P (arg) = 1;
|
|
|
1186 tree tmp = get_or_create_ssa_default_def (cfun, arg);
|
|
|
1187 g = gimple_build_assign (var, tmp);
|
|
|
1188 gimple_set_location (g, DECL_SOURCE_LOCATION (arg));
|
|
|
1189 gimple_seq_add_stmt (&stmts, g);
|
|
|
1190 }
|
|
|
1191 else
|
|
|
1192 {
|
|
|
1193 g = gimple_build_assign (var, arg);
|
|
|
1194 gimple_set_location (g, DECL_SOURCE_LOCATION (arg));
|
|
|
1195 gimple_seq_add_stmt (&stmts, g);
|
|
|
1196 }
|
|
|
1197
|
|
|
1198 if (target_for_debug_bind (arg))
|
|
|
1199 {
|
|
|
1200 g = gimple_build_debug_bind (arg, var, NULL);
|
|
|
1201 gimple_seq_add_stmt (&stmts, g);
|
|
|
1202 clear_value_expr_list.safe_push (arg);
|
|
|
1203 }
|
|
|
1204
|
|
|
1205 DECL_HAS_VALUE_EXPR_P (arg) = 1;
|
|
|
1206 SET_DECL_VALUE_EXPR (arg, var);
|
|
|
1207 }
|
|
|
1208 }
|
|
|
1209
|
|
|
1210 if (!has_any_addressable_param)
|
|
|
1211 return;
|
|
|
1212
|
|
|
1213 /* Replace all usages of PARM_DECLs with the newly
|
|
|
1214 created variable VAR. */
|
|
|
1215 basic_block bb;
|
|
|
1216 FOR_EACH_BB_FN (bb, fun)
|
|
|
1217 {
|
|
|
1218 gimple_stmt_iterator gsi;
|
|
|
1219 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
|
|
1220 {
|
|
|
1221 gimple *stmt = gsi_stmt (gsi);
|
|
|
1222 gimple_stmt_iterator it = gsi_for_stmt (stmt);
|
|
|
1223 walk_gimple_stmt (&it, NULL, rewrite_usage_of_param, NULL);
|
|
|
1224 }
|
|
|
1225 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
|
|
1226 {
|
|
|
1227 gphi *phi = dyn_cast<gphi *> (gsi_stmt (gsi));
|
|
|
1228 for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i)
|
|
|
1229 {
|
|
|
1230 hash_set<tree> visited_nodes;
|
|
|
1231 walk_tree (gimple_phi_arg_def_ptr (phi, i),
|
|
|
1232 rewrite_usage_of_param, NULL, &visited_nodes);
|
|
|
1233 }
|
|
|
1234 }
|
|
|
1235 }
|
|
|
1236
|
|
|
1237 /* Unset value expr for parameters for which we created debug bind
|
|
|
1238 expressions. */
|
|
|
1239 unsigned i;
|
|
|
1240 tree arg;
|
|
|
1241 FOR_EACH_VEC_ELT (clear_value_expr_list, i, arg)
|
|
|
1242 {
|
|
|
1243 DECL_HAS_VALUE_EXPR_P (arg) = 0;
|
|
|
1244 SET_DECL_VALUE_EXPR (arg, NULL_TREE);
|
|
|
1245 }
|
|
|
1246
|
|
|
1247 /* Insert default assignments at the beginning of a function. */
|
|
|
1248 basic_block entry_bb = ENTRY_BLOCK_PTR_FOR_FN (fun);
|
|
|
1249 entry_bb = split_edge (single_succ_edge (entry_bb));
|
|
|
1250
|
|
|
1251 gimple_stmt_iterator gsi = gsi_start_bb (entry_bb);
|
|
|
1252 gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT);
|
|
|
1253 }
|
|
|
1254
|
|
|
1255 unsigned int
|
|
|
1256 pass_sanopt::execute (function *fun)
|
|
|
1257 {
|
|
|
1258 basic_block bb;
|
|
|
1259 int asan_num_accesses = 0;
|
|
|
1260 bool contains_asan_mark = false;
|
|
|
1261
|
|
|
1262 /* Try to remove redundant checks. */
|
|
|
1263 if (optimize
|
|
|
1264 && (flag_sanitize
|
|
|
1265 & (SANITIZE_NULL | SANITIZE_ALIGNMENT
|
|
|
1266 | SANITIZE_ADDRESS | SANITIZE_VPTR | SANITIZE_POINTER_OVERFLOW)))
|
|
|
1267 asan_num_accesses = sanopt_optimize (fun, &contains_asan_mark);
|
|
|
1268 else if (flag_sanitize & SANITIZE_ADDRESS)
|
|
|
1269 {
|
|
|
1270 gimple_stmt_iterator gsi;
|
|
|
1271 FOR_EACH_BB_FN (bb, fun)
|
|
|
1272 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
|
|
1273 {
|
|
|
1274 gimple *stmt = gsi_stmt (gsi);
|
|
|
1275 if (gimple_call_internal_p (stmt, IFN_ASAN_CHECK))
|
|
|
1276 ++asan_num_accesses;
|
|
|
1277 else if (gimple_call_internal_p (stmt, IFN_ASAN_MARK))
|
|
|
1278 contains_asan_mark = true;
|
|
|
1279 }
|
|
|
1280 }
|
|
|
1281
|
|
|
1282 if (contains_asan_mark)
|
|
|
1283 {
|
|
|
1284 sanitize_asan_mark_unpoison ();
|
|
|
1285 sanitize_asan_mark_poison ();
|
|
|
1286 }
|
|
|
1287
|
|
|
1288 if (asan_sanitize_stack_p ())
|
|
|
1289 sanitize_rewrite_addressable_params (fun);
|
|
|
1290
|
|
|
1291 bool use_calls = ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD < INT_MAX
|
|
|
1292 && asan_num_accesses >= ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD;
|
|
|
1293
|
|
|
1294 hash_map<tree, tree> shadow_vars_mapping;
|
|
|
1295 bool need_commit_edge_insert = false;
|
|
|
1296 FOR_EACH_BB_FN (bb, fun)
|
|
|
1297 {
|
|
|
1298 gimple_stmt_iterator gsi;
|
|
|
1299 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
|
|
|
1300 {
|
|
|
1301 gimple *stmt = gsi_stmt (gsi);
|
|
|
1302 bool no_next = false;
|
|
|
1303
|
|
|
1304 if (!is_gimple_call (stmt))
|
|
|
1305 {
|
|
|
1306 gsi_next (&gsi);
|
|
|
1307 continue;
|
|
|
1308 }
|
|
|
1309
|
|
|
1310 if (gimple_call_internal_p (stmt))
|
|
|
1311 {
|
|
|
1312 enum internal_fn ifn = gimple_call_internal_fn (stmt);
|
|
|
1313 switch (ifn)
|
|
|
1314 {
|
|
|
1315 case IFN_UBSAN_NULL:
|
|
|
1316 no_next = ubsan_expand_null_ifn (&gsi);
|
|
|
1317 break;
|
|
|
1318 case IFN_UBSAN_BOUNDS:
|
|
|
1319 no_next = ubsan_expand_bounds_ifn (&gsi);
|
|
|
1320 break;
|
|
|
1321 case IFN_UBSAN_OBJECT_SIZE:
|
|
|
1322 no_next = ubsan_expand_objsize_ifn (&gsi);
|
|
|
1323 break;
|
|
|
1324 case IFN_UBSAN_PTR:
|
|
|
1325 no_next = ubsan_expand_ptr_ifn (&gsi);
|
|
|
1326 break;
|
|
|
1327 case IFN_UBSAN_VPTR:
|
|
|
1328 no_next = ubsan_expand_vptr_ifn (&gsi);
|
|
|
1329 break;
|
|
|
1330 case IFN_ASAN_CHECK:
|
|
|
1331 no_next = asan_expand_check_ifn (&gsi, use_calls);
|
|
|
1332 break;
|
|
|
1333 case IFN_ASAN_MARK:
|
|
|
1334 no_next = asan_expand_mark_ifn (&gsi);
|
|
|
1335 break;
|
|
|
1336 case IFN_ASAN_POISON:
|
|
|
1337 no_next = asan_expand_poison_ifn (&gsi,
|
|
|
1338 &need_commit_edge_insert,
|
|
|
1339 shadow_vars_mapping);
|
|
|
1340 break;
|
|
|
1341 default:
|
|
|
1342 break;
|
|
|
1343 }
|
|
|
1344 }
|
|
|
1345 else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
|
|
|
1346 {
|
|
|
1347 tree callee = gimple_call_fndecl (stmt);
|
|
|
1348 switch (DECL_FUNCTION_CODE (callee))
|
|
|
1349 {
|
|
|
1350 case BUILT_IN_UNREACHABLE:
|
|
|
1351 if (sanitize_flags_p (SANITIZE_UNREACHABLE))
|
|
|
1352 no_next = ubsan_instrument_unreachable (&gsi);
|
|
|
1353 break;
|
|
|
1354 default:
|
|
|
1355 break;
|
|
|
1356 }
|
|
|
1357 }
|
|
|
1358
|
|
|
1359 if (dump_file && (dump_flags & TDF_DETAILS))
|
|
|
1360 {
|
|
|
1361 fprintf (dump_file, "Expanded: ");
|
|
|
1362 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
|
|
|
1363 }
|
|
|
1364
|
|
|
1365 if (!no_next)
|
|
|
1366 gsi_next (&gsi);
|
|
|
1367 }
|
|
|
1368 }
|
|
|
1369
|
|
|
1370 if (need_commit_edge_insert)
|
|
|
1371 gsi_commit_edge_inserts ();
|
|
|
1372
|
|
|
1373 return 0;
|
|
|
1374 }
|
|
|
1375
|
|
|
1376 } // anon namespace
|
|
|
1377
|
|
|
1378 gimple_opt_pass *
|
|
|
1379 make_pass_sanopt (gcc::context *ctxt)
|
|
|
1380 {
|
|
|
1381 return new pass_sanopt (ctxt);
|
|
|
1382 }
|
