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0
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1 /* Type based alias analysis.
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2 Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation,
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3 Inc.
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4 Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
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5
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6 This file is part of GCC.
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7
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8 GCC is free software; you can redistribute it and/or modify it under
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9 the terms of the GNU General Public License as published by the Free
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10 Software Foundation; either version 3, or (at your option) any later
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11 version.
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12
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13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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16 for more details.
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17
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18 You should have received a copy of the GNU General Public License
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19 along with GCC; see the file COPYING3. If not see
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20 <http://www.gnu.org/licenses/>. */
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21
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22 /* This pass determines which types in the program contain only
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23 instances that are completely encapsulated by the compilation unit.
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24 Those types that are encapsulated must also pass the further
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25 requirement that there be no bad operations on any instances of
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26 those types.
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27
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28 A great deal of freedom in compilation is allowed for the instances
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29 of those types that pass these conditions.
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30 */
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31
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32 /* The code in this module is called by the ipa pass manager. It
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33 should be one of the later passes since its information is used by
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34 the rest of the compilation. */
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35
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36 #include "config.h"
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37 #include "system.h"
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38 #include "coretypes.h"
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39 #include "tm.h"
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40 #include "tree.h"
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41 #include "tree-flow.h"
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42 #include "tree-inline.h"
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43 #include "tree-pass.h"
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44 #include "langhooks.h"
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45 #include "pointer-set.h"
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46 #include "ggc.h"
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47 #include "ipa-utils.h"
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48 #include "ipa-type-escape.h"
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49 #include "c-common.h"
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50 #include "gimple.h"
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51 #include "cgraph.h"
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52 #include "output.h"
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53 #include "flags.h"
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54 #include "timevar.h"
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55 #include "diagnostic.h"
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56 #include "langhooks.h"
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57
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58 /* Some of the aliasing is called very early, before this phase is
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59 called. To assure that this is not a problem, we keep track of if
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60 this phase has been run. */
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61 static bool initialized = false;
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62
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63 /* Scratch bitmap for avoiding work. */
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64 static bitmap been_there_done_that;
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65 static bitmap bitmap_tmp;
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66
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67 /* There are two levels of escape that types can undergo.
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68
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69 EXPOSED_PARAMETER - some instance of the variable is
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70 passed by value into an externally visible function or some
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71 instance of the variable is passed out of an externally visible
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72 function as a return value. In this case any of the fields of the
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73 variable that are pointer types end up having their types marked as
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74 FULL_ESCAPE.
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75
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76 FULL_ESCAPE - when bad things happen to good types. One of the
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77 following things happens to the type: (a) either an instance of the
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78 variable has its address passed to an externally visible function,
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79 (b) the address is taken and some bad cast happens to the address
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80 or (c) explicit arithmetic is done to the address.
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81 */
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82
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83 enum escape_t
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84 {
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85 EXPOSED_PARAMETER,
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86 FULL_ESCAPE
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87 };
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88
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89 /* The following two bit vectors global_types_* correspond to
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90 previous cases above. During the analysis phase, a bit is set in
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91 one of these vectors if an operation of the offending class is
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92 discovered to happen on the associated type. */
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93
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94 static bitmap global_types_exposed_parameter;
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95 static bitmap global_types_full_escape;
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96
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97 /* All of the types seen in this compilation unit. */
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98 static bitmap global_types_seen;
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99 /* Reverse map to take a canon uid and map it to a canon type. Uid's
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100 are never manipulated unless they are associated with a canon
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101 type. */
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102 static splay_tree uid_to_canon_type;
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103
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104 /* Internal structure of type mapping code. This maps a canon type
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105 name to its canon type. */
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106 static splay_tree all_canon_types;
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107
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108 /* Map from type clones to the single canon type. */
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109 static splay_tree type_to_canon_type;
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110
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111 /* A splay tree of bitmaps. An element X in the splay tree has a bit
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112 set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (Y)) if there was
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113 an operation in the program of the form "&X.Y". */
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114 static splay_tree uid_to_addressof_down_map;
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115
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116 /* A splay tree of bitmaps. An element Y in the splay tree has a bit
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117 set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (X)) if there was
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118 an operation in the program of the form "&X.Y". */
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119 static splay_tree uid_to_addressof_up_map;
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120
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121 /* Tree to hold the subtype maps used to mark subtypes of escaped
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122 types. */
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123 static splay_tree uid_to_subtype_map;
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124
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125 /* Records tree nodes seen in cgraph_create_edges. Simply using
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126 walk_tree_without_duplicates doesn't guarantee each node is visited
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127 once because it gets a new htab upon each recursive call from
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128 scan_for_refs. */
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129 static struct pointer_set_t *visited_nodes;
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130
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131 /* Visited stmts by walk_use_def_chains function because it's called
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132 recursively. */
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133 static struct pointer_set_t *visited_stmts;
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134
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135 static bitmap_obstack ipa_obstack;
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136
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137 /* Static functions from this file that are used
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138 before being defined. */
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139 static unsigned int look_for_casts (tree);
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140 static bool is_cast_from_non_pointer (tree, gimple, void *);
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141
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142 /* Get the name of TYPE or return the string "<UNNAMED>". */
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143 static const char*
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144 get_name_of_type (tree type)
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145 {
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146 tree name = TYPE_NAME (type);
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147
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148 if (!name)
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149 /* Unnamed type, do what you like here. */
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150 return "<UNNAMED>";
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151
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152 /* It will be a TYPE_DECL in the case of a typedef, otherwise, an
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153 identifier_node */
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154 if (TREE_CODE (name) == TYPE_DECL)
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155 {
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156 /* Each DECL has a DECL_NAME field which contains an
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157 IDENTIFIER_NODE. (Some decls, most often labels, may have
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158 zero as the DECL_NAME). */
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159 if (DECL_NAME (name))
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160 return IDENTIFIER_POINTER (DECL_NAME (name));
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161 else
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162 /* Unnamed type, do what you like here. */
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163 return "<UNNAMED>";
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164 }
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165 else if (TREE_CODE (name) == IDENTIFIER_NODE)
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166 return IDENTIFIER_POINTER (name);
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167 else
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168 return "<UNNAMED>";
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169 }
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170
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171 struct type_brand_s
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172 {
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173 const char* name;
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174 int seq;
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175 };
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176
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177 /* Splay tree comparison function on type_brand_s structures. */
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178
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179 static int
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180 compare_type_brand (splay_tree_key sk1, splay_tree_key sk2)
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181 {
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182 struct type_brand_s * k1 = (struct type_brand_s *) sk1;
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183 struct type_brand_s * k2 = (struct type_brand_s *) sk2;
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184
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185 int value = strcmp(k1->name, k2->name);
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186 if (value == 0)
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187 return k2->seq - k1->seq;
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188 else
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189 return value;
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190 }
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191
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192 /* All of the "unique_type" code is a hack to get around the sleazy
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193 implementation used to compile more than file. Currently gcc does
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194 not get rid of multiple instances of the same type that have been
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195 collected from different compilation units. */
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196 /* This is a trivial algorithm for removing duplicate types. This
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197 would not work for any language that used structural equivalence as
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198 the basis of its type system. */
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199 /* Return TYPE if no type compatible with TYPE has been seen so far,
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200 otherwise return a type compatible with TYPE that has already been
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201 processed. */
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202
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203 static tree
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204 discover_unique_type (tree type)
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205 {
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206 struct type_brand_s * brand = XNEW (struct type_brand_s);
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207 int i = 0;
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208 splay_tree_node result;
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209
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210 brand->name = get_name_of_type (type);
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211
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212 while (1)
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213 {
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214 brand->seq = i++;
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215 result = splay_tree_lookup (all_canon_types, (splay_tree_key) brand);
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216
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217 if (result)
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218 {
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219 /* Create an alias since this is just the same as
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220 other_type. */
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221 tree other_type = (tree) result->value;
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222 if (types_compatible_p (type, other_type))
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223 {
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224 free (brand);
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225 /* Insert this new type as an alias for other_type. */
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226 splay_tree_insert (type_to_canon_type,
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227 (splay_tree_key) type,
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228 (splay_tree_value) other_type);
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229 return other_type;
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230 }
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231 /* Not compatible, look for next instance with same name. */
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232 }
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233 else
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234 {
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235 /* No more instances, create new one since this is the first
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236 time we saw this type. */
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237 brand->seq = i++;
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238 /* Insert the new brand. */
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239 splay_tree_insert (all_canon_types,
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240 (splay_tree_key) brand,
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241 (splay_tree_value) type);
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242
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243 /* Insert this new type as an alias for itself. */
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244 splay_tree_insert (type_to_canon_type,
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245 (splay_tree_key) type,
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246 (splay_tree_value) type);
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247
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248 /* Insert the uid for reverse lookup; */
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249 splay_tree_insert (uid_to_canon_type,
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250 (splay_tree_key) TYPE_UID (type),
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251 (splay_tree_value) type);
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252
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253 bitmap_set_bit (global_types_seen, TYPE_UID (type));
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254 return type;
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255 }
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256 }
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257 }
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258
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259 /* Return true if TYPE is one of the type classes that we are willing
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260 to analyze. This skips the goofy types like arrays of pointers to
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261 methods. */
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262 static bool
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263 type_to_consider (tree type)
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264 {
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265 /* Strip the *'s off. */
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266 type = TYPE_MAIN_VARIANT (type);
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267 while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE)
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268 type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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269
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270 switch (TREE_CODE (type))
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271 {
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272 case BOOLEAN_TYPE:
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273 case COMPLEX_TYPE:
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274 case ENUMERAL_TYPE:
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275 case INTEGER_TYPE:
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276 case QUAL_UNION_TYPE:
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277 case REAL_TYPE:
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278 case FIXED_POINT_TYPE:
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279 case RECORD_TYPE:
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280 case UNION_TYPE:
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281 case VECTOR_TYPE:
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282 case VOID_TYPE:
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283 return true;
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284
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285 default:
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286 return false;
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287 }
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288 }
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289
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290 /* Get the canon type of TYPE. If SEE_THRU_PTRS is true, remove all
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291 the POINTER_TOs and if SEE_THRU_ARRAYS is true, remove all of the
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292 ARRAY_OFs and POINTER_TOs. */
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293
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294 static tree
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295 get_canon_type (tree type, bool see_thru_ptrs, bool see_thru_arrays)
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296 {
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297 splay_tree_node result;
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298 /* Strip the *'s off. */
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299 if (!type || !type_to_consider (type))
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300 return NULL;
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301
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302 type = TYPE_MAIN_VARIANT (type);
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303 if (see_thru_arrays)
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304 while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE)
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305 type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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306
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307 else if (see_thru_ptrs)
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308 while (POINTER_TYPE_P (type))
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309 type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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310
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311 result = splay_tree_lookup (type_to_canon_type, (splay_tree_key) type);
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312
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313 if (result == NULL)
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314 return discover_unique_type (type);
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315 else return (tree) result->value;
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316 }
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317
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318 /* Same as GET_CANON_TYPE, except return the TYPE_ID rather than the
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319 TYPE. */
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320
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321 static int
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322 get_canon_type_uid (tree type, bool see_thru_ptrs, bool see_thru_arrays)
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323 {
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324 type = get_canon_type (type, see_thru_ptrs, see_thru_arrays);
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325 if (type)
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326 return TYPE_UID(type);
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327 else return 0;
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328 }
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329
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330 /* Return 0 if TYPE is a record or union type. Return a positive
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331 number if TYPE is a pointer to a record or union. The number is
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332 the number of pointer types stripped to get to the record or union
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333 type. Return -1 if TYPE is none of the above. */
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334
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335 int
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336 ipa_type_escape_star_count_of_interesting_type (tree type)
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337 {
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338 int count = 0;
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339 /* Strip the *'s off. */
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340 if (!type)
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341 return -1;
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342 type = TYPE_MAIN_VARIANT (type);
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343 while (POINTER_TYPE_P (type))
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344 {
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345 type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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346 count++;
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347 }
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348
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349 /* We are interested in records, and unions only. */
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350 if (TREE_CODE (type) == RECORD_TYPE
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351 || TREE_CODE (type) == QUAL_UNION_TYPE
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352 || TREE_CODE (type) == UNION_TYPE)
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353 return count;
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354 else
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355 return -1;
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356 }
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357
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358
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359 /* Return 0 if TYPE is a record or union type. Return a positive
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360 number if TYPE is a pointer to a record or union. The number is
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361 the number of pointer types stripped to get to the record or union
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362 type. Return -1 if TYPE is none of the above. */
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363
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364 int
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365 ipa_type_escape_star_count_of_interesting_or_array_type (tree type)
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366 {
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367 int count = 0;
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368 /* Strip the *'s off. */
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369 if (!type)
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370 return -1;
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371 type = TYPE_MAIN_VARIANT (type);
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372 while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE)
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373 {
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374 type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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375 count++;
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376 }
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377
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378 /* We are interested in records, and unions only. */
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379 if (TREE_CODE (type) == RECORD_TYPE
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380 || TREE_CODE (type) == QUAL_UNION_TYPE
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381 || TREE_CODE (type) == UNION_TYPE)
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382 return count;
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383 else
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384 return -1;
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385 }
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386
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387
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388 /* Return true if the record, or union TYPE passed in escapes this
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389 compilation unit. Note that all of the pointer-to's are removed
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390 before testing since these may not be correct. */
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391
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392 bool
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393 ipa_type_escape_type_contained_p (tree type)
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394 {
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395 if (!initialized)
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396 return false;
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397 return !bitmap_bit_p (global_types_full_escape,
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398 get_canon_type_uid (type, true, false));
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399 }
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400
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401 /* Return true if a modification to a field of type FIELD_TYPE cannot
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402 clobber a record of RECORD_TYPE. */
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403
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404 bool
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405 ipa_type_escape_field_does_not_clobber_p (tree record_type, tree field_type)
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406 {
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407 splay_tree_node result;
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408 int uid;
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409
|
|
|
410 if (!initialized)
|
|
|
411 return false;
|
|
|
412
|
|
|
413 /* Strip off all of the pointer tos on the record type. Strip the
|
|
|
414 same number of pointer tos from the field type. If the field
|
|
|
415 type has fewer, it could not have been aliased. */
|
|
|
416 record_type = TYPE_MAIN_VARIANT (record_type);
|
|
|
417 field_type = TYPE_MAIN_VARIANT (field_type);
|
|
|
418 while (POINTER_TYPE_P (record_type))
|
|
|
419 {
|
|
|
420 record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type));
|
|
|
421 if (POINTER_TYPE_P (field_type))
|
|
|
422 field_type = TYPE_MAIN_VARIANT (TREE_TYPE (field_type));
|
|
|
423 else
|
|
|
424 /* However, if field_type is a union, this quick test is not
|
|
|
425 correct since one of the variants of the union may be a
|
|
|
426 pointer to type and we cannot see across that here. So we
|
|
|
427 just strip the remaining pointer tos off the record type
|
|
|
428 and fall thru to the more precise code. */
|
|
|
429 if (TREE_CODE (field_type) == QUAL_UNION_TYPE
|
|
|
430 || TREE_CODE (field_type) == UNION_TYPE)
|
|
|
431 {
|
|
|
432 while (POINTER_TYPE_P (record_type))
|
|
|
433 record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type));
|
|
|
434 break;
|
|
|
435 }
|
|
|
436 else
|
|
|
437 return true;
|
|
|
438 }
|
|
|
439
|
|
|
440 record_type = get_canon_type (record_type, true, true);
|
|
|
441 /* The record type must be contained. The field type may
|
|
|
442 escape. */
|
|
|
443 if (!ipa_type_escape_type_contained_p (record_type))
|
|
|
444 return false;
|
|
|
445
|
|
|
446 uid = TYPE_UID (record_type);
|
|
|
447 result = splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid);
|
|
|
448
|
|
|
449 if (result)
|
|
|
450 {
|
|
|
451 bitmap field_type_map = (bitmap) result->value;
|
|
|
452 uid = get_canon_type_uid (field_type, true, true);
|
|
|
453 /* If the bit is there, the address was taken. If not, it
|
|
|
454 wasn't. */
|
|
|
455 return !bitmap_bit_p (field_type_map, uid);
|
|
|
456 }
|
|
|
457 else
|
|
|
458 /* No bitmap means no addresses were taken. */
|
|
|
459 return true;
|
|
|
460 }
|
|
|
461
|
|
|
462
|
|
|
463 /* Add TYPE to the suspect type set. Return true if the bit needed to
|
|
|
464 be marked. */
|
|
|
465
|
|
|
466 static tree
|
|
|
467 mark_type (tree type, enum escape_t escape_status)
|
|
|
468 {
|
|
|
469 bitmap map = NULL;
|
|
|
470 int uid;
|
|
|
471
|
|
|
472 type = get_canon_type (type, true, true);
|
|
|
473 if (!type)
|
|
|
474 return NULL;
|
|
|
475
|
|
|
476 switch (escape_status)
|
|
|
477 {
|
|
|
478 case EXPOSED_PARAMETER:
|
|
|
479 map = global_types_exposed_parameter;
|
|
|
480 break;
|
|
|
481 case FULL_ESCAPE:
|
|
|
482 map = global_types_full_escape;
|
|
|
483 break;
|
|
|
484 }
|
|
|
485
|
|
|
486 uid = TYPE_UID (type);
|
|
|
487 if (bitmap_bit_p (map, uid))
|
|
|
488 return type;
|
|
|
489 else
|
|
|
490 {
|
|
|
491 bitmap_set_bit (map, uid);
|
|
|
492 if (escape_status == FULL_ESCAPE)
|
|
|
493 {
|
|
|
494 /* Efficiency hack. When things are bad, do not mess around
|
|
|
495 with this type anymore. */
|
|
|
496 bitmap_set_bit (global_types_exposed_parameter, uid);
|
|
|
497 }
|
|
|
498 }
|
|
|
499 return type;
|
|
|
500 }
|
|
|
501
|
|
|
502 /* Add interesting TYPE to the suspect type set. If the set is
|
|
|
503 EXPOSED_PARAMETER and the TYPE is a pointer type, the set is
|
|
|
504 changed to FULL_ESCAPE. */
|
|
|
505
|
|
|
506 static void
|
|
|
507 mark_interesting_type (tree type, enum escape_t escape_status)
|
|
|
508 {
|
|
|
509 if (!type) return;
|
|
|
510 if (ipa_type_escape_star_count_of_interesting_type (type) >= 0)
|
|
|
511 {
|
|
|
512 if ((escape_status == EXPOSED_PARAMETER)
|
|
|
513 && POINTER_TYPE_P (type))
|
|
|
514 /* EXPOSED_PARAMETERs are only structs or unions are passed by
|
|
|
515 value. Anything passed by reference to an external
|
|
|
516 function fully exposes the type. */
|
|
|
517 mark_type (type, FULL_ESCAPE);
|
|
|
518 else
|
|
|
519 mark_type (type, escape_status);
|
|
|
520 }
|
|
|
521 }
|
|
|
522
|
|
|
523 /* Return true if PARENT is supertype of CHILD. Both types must be
|
|
|
524 known to be structures or unions. */
|
|
|
525
|
|
|
526 static bool
|
|
|
527 parent_type_p (tree parent, tree child)
|
|
|
528 {
|
|
|
529 int i;
|
|
|
530 tree binfo, base_binfo;
|
|
|
531 if (TYPE_BINFO (parent))
|
|
|
532 for (binfo = TYPE_BINFO (parent), i = 0;
|
|
|
533 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
|
|
|
534 {
|
|
|
535 tree binfotype = BINFO_TYPE (base_binfo);
|
|
|
536 if (binfotype == child)
|
|
|
537 return true;
|
|
|
538 else if (parent_type_p (binfotype, child))
|
|
|
539 return true;
|
|
|
540 }
|
|
|
541 if (TREE_CODE (parent) == UNION_TYPE
|
|
|
542 || TREE_CODE (parent) == QUAL_UNION_TYPE)
|
|
|
543 {
|
|
|
544 tree field;
|
|
|
545 /* Search all of the variants in the union to see if one of them
|
|
|
546 is the child. */
|
|
|
547 for (field = TYPE_FIELDS (parent);
|
|
|
548 field;
|
|
|
549 field = TREE_CHAIN (field))
|
|
|
550 {
|
|
|
551 tree field_type;
|
|
|
552 if (TREE_CODE (field) != FIELD_DECL)
|
|
|
553 continue;
|
|
|
554
|
|
|
555 field_type = TREE_TYPE (field);
|
|
|
556 if (field_type == child)
|
|
|
557 return true;
|
|
|
558 }
|
|
|
559
|
|
|
560 /* If we did not find it, recursively ask the variants if one of
|
|
|
561 their children is the child type. */
|
|
|
562 for (field = TYPE_FIELDS (parent);
|
|
|
563 field;
|
|
|
564 field = TREE_CHAIN (field))
|
|
|
565 {
|
|
|
566 tree field_type;
|
|
|
567 if (TREE_CODE (field) != FIELD_DECL)
|
|
|
568 continue;
|
|
|
569
|
|
|
570 field_type = TREE_TYPE (field);
|
|
|
571 if (TREE_CODE (field_type) == RECORD_TYPE
|
|
|
572 || TREE_CODE (field_type) == QUAL_UNION_TYPE
|
|
|
573 || TREE_CODE (field_type) == UNION_TYPE)
|
|
|
574 if (parent_type_p (field_type, child))
|
|
|
575 return true;
|
|
|
576 }
|
|
|
577 }
|
|
|
578
|
|
|
579 if (TREE_CODE (parent) == RECORD_TYPE)
|
|
|
580 {
|
|
|
581 tree field;
|
|
|
582 for (field = TYPE_FIELDS (parent);
|
|
|
583 field;
|
|
|
584 field = TREE_CHAIN (field))
|
|
|
585 {
|
|
|
586 tree field_type;
|
|
|
587 if (TREE_CODE (field) != FIELD_DECL)
|
|
|
588 continue;
|
|
|
589
|
|
|
590 field_type = TREE_TYPE (field);
|
|
|
591 if (field_type == child)
|
|
|
592 return true;
|
|
|
593 /* You can only cast to the first field so if it does not
|
|
|
594 match, quit. */
|
|
|
595 if (TREE_CODE (field_type) == RECORD_TYPE
|
|
|
596 || TREE_CODE (field_type) == QUAL_UNION_TYPE
|
|
|
597 || TREE_CODE (field_type) == UNION_TYPE)
|
|
|
598 {
|
|
|
599 if (parent_type_p (field_type, child))
|
|
|
600 return true;
|
|
|
601 else
|
|
|
602 break;
|
|
|
603 }
|
|
|
604 }
|
|
|
605 }
|
|
|
606 return false;
|
|
|
607 }
|
|
|
608
|
|
|
609 /* Return the number of pointer tos for TYPE and return TYPE with all
|
|
|
610 of these stripped off. */
|
|
|
611
|
|
|
612 static int
|
|
|
613 count_stars (tree* type_ptr)
|
|
|
614 {
|
|
|
615 tree type = *type_ptr;
|
|
|
616 int i = 0;
|
|
|
617 type = TYPE_MAIN_VARIANT (type);
|
|
|
618 while (POINTER_TYPE_P (type))
|
|
|
619 {
|
|
|
620 type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
|
|
|
621 i++;
|
|
|
622 }
|
|
|
623
|
|
|
624 *type_ptr = type;
|
|
|
625 return i;
|
|
|
626 }
|
|
|
627
|
|
|
628 enum cast_type {
|
|
|
629 CT_UP = 0x1,
|
|
|
630 CT_DOWN = 0x2,
|
|
|
631 CT_SIDEWAYS = 0x4,
|
|
|
632 CT_USELESS = 0x8,
|
|
|
633 CT_FROM_P_BAD = 0x10,
|
|
|
634 CT_FROM_NON_P = 0x20,
|
|
|
635 CT_TO_NON_INTER = 0x40,
|
|
|
636 CT_FROM_MALLOC = 0x80,
|
|
|
637 CT_NO_CAST = 0x100
|
|
|
638 };
|
|
|
639
|
|
|
640 /* Check the cast FROM_TYPE to TO_TYPE. This function requires that
|
|
|
641 the two types have already passed the
|
|
|
642 ipa_type_escape_star_count_of_interesting_type test. */
|
|
|
643
|
|
|
644 static enum cast_type
|
|
|
645 check_cast_type (tree to_type, tree from_type)
|
|
|
646 {
|
|
|
647 int to_stars = count_stars (&to_type);
|
|
|
648 int from_stars = count_stars (&from_type);
|
|
|
649 if (to_stars != from_stars)
|
|
|
650 return CT_SIDEWAYS;
|
|
|
651
|
|
|
652 if (to_type == from_type)
|
|
|
653 return CT_USELESS;
|
|
|
654
|
|
|
655 if (parent_type_p (to_type, from_type)) return CT_UP;
|
|
|
656 if (parent_type_p (from_type, to_type)) return CT_DOWN;
|
|
|
657 return CT_SIDEWAYS;
|
|
|
658 }
|
|
|
659
|
|
|
660 /* This function returns nonzero if VAR is result of call
|
|
|
661 to malloc function. */
|
|
|
662
|
|
|
663 static bool
|
|
|
664 is_malloc_result (tree var)
|
|
|
665 {
|
|
|
666 gimple def_stmt;
|
|
|
667
|
|
|
668 if (!var)
|
|
|
669 return false;
|
|
|
670
|
|
|
671 if (SSA_NAME_IS_DEFAULT_DEF (var))
|
|
|
672 return false;
|
|
|
673
|
|
|
674 def_stmt = SSA_NAME_DEF_STMT (var);
|
|
|
675
|
|
|
676 if (!is_gimple_call (def_stmt))
|
|
|
677 return false;
|
|
|
678
|
|
|
679 if (var != gimple_call_lhs (def_stmt))
|
|
|
680 return false;
|
|
|
681
|
|
|
682 return ((gimple_call_flags (def_stmt) & ECF_MALLOC) != 0);
|
|
|
683
|
|
|
684 }
|
|
|
685
|
|
|
686 /* Check a cast FROM this variable, TO_TYPE. Mark the escaping types
|
|
|
687 if appropriate. Returns cast_type as detected. */
|
|
|
688
|
|
|
689 static enum cast_type
|
|
|
690 check_cast (tree to_type, tree from)
|
|
|
691 {
|
|
|
692 tree from_type = get_canon_type (TREE_TYPE (from), false, false);
|
|
|
693 bool to_interesting_type, from_interesting_type;
|
|
|
694 enum cast_type cast = CT_NO_CAST;
|
|
|
695
|
|
|
696 to_type = get_canon_type (to_type, false, false);
|
|
|
697 if (!from_type || !to_type || from_type == to_type)
|
|
|
698 return cast;
|
|
|
699
|
|
|
700 to_interesting_type =
|
|
|
701 ipa_type_escape_star_count_of_interesting_type (to_type) >= 0;
|
|
|
702 from_interesting_type =
|
|
|
703 ipa_type_escape_star_count_of_interesting_type (from_type) >= 0;
|
|
|
704
|
|
|
705 if (to_interesting_type)
|
|
|
706 if (from_interesting_type)
|
|
|
707 {
|
|
|
708 /* Both types are interesting. This can be one of four types
|
|
|
709 of cast: useless, up, down, or sideways. We do not care
|
|
|
710 about up or useless. Sideways casts are always bad and
|
|
|
711 both sides get marked as escaping. Downcasts are not
|
|
|
712 interesting here because if type is marked as escaping, all
|
|
|
713 of its subtypes escape. */
|
|
|
714 cast = check_cast_type (to_type, from_type);
|
|
|
715 switch (cast)
|
|
|
716 {
|
|
|
717 case CT_UP:
|
|
|
718 case CT_USELESS:
|
|
|
719 case CT_DOWN:
|
|
|
720 break;
|
|
|
721
|
|
|
722 case CT_SIDEWAYS:
|
|
|
723 mark_type (to_type, FULL_ESCAPE);
|
|
|
724 mark_type (from_type, FULL_ESCAPE);
|
|
|
725 break;
|
|
|
726
|
|
|
727 default:
|
|
|
728 break;
|
|
|
729 }
|
|
|
730 }
|
|
|
731 else
|
|
|
732 {
|
|
|
733 /* This code excludes two cases from marking as escaped:
|
|
|
734
|
|
|
735 1. if this is a cast of index of array of structures/unions
|
|
|
736 that happens before accessing array element, we should not
|
|
|
737 mark it as escaped.
|
|
|
738 2. if this is a cast from the local that is a result from a
|
|
|
739 call to malloc, do not mark the cast as bad.
|
|
|
740
|
|
|
741 */
|
|
|
742
|
|
|
743 if (POINTER_TYPE_P (to_type) && !POINTER_TYPE_P (from_type))
|
|
|
744 cast = CT_FROM_NON_P;
|
|
|
745 else if (TREE_CODE (from) == SSA_NAME
|
|
|
746 && is_malloc_result (from))
|
|
|
747 cast = CT_FROM_MALLOC;
|
|
|
748 else
|
|
|
749 {
|
|
|
750 cast = CT_FROM_P_BAD;
|
|
|
751 mark_type (to_type, FULL_ESCAPE);
|
|
|
752 }
|
|
|
753 }
|
|
|
754 else if (from_interesting_type)
|
|
|
755 {
|
|
|
756 mark_type (from_type, FULL_ESCAPE);
|
|
|
757 cast = CT_TO_NON_INTER;
|
|
|
758 }
|
|
|
759
|
|
|
760 return cast;
|
|
|
761 }
|
|
|
762
|
|
|
763
|
|
|
764 /* Scan assignment statement S to see if there are any casts within it. */
|
|
|
765
|
|
|
766 static unsigned int
|
|
|
767 look_for_casts_stmt (gimple s)
|
|
|
768 {
|
|
|
769 unsigned int cast = 0;
|
|
|
770
|
|
|
771 gcc_assert (is_gimple_assign (s));
|
|
|
772
|
|
|
773 if (gimple_assign_cast_p (s))
|
|
|
774 {
|
|
|
775 tree castfromvar = gimple_assign_rhs1 (s);
|
|
|
776 cast |= check_cast (TREE_TYPE (gimple_assign_lhs (s)), castfromvar);
|
|
|
777 }
|
|
|
778 else
|
|
|
779 {
|
|
|
780 size_t i;
|
|
|
781 for (i = 0; i < gimple_num_ops (s); i++)
|
|
|
782 cast |= look_for_casts (gimple_op (s, i));
|
|
|
783 }
|
|
|
784
|
|
|
785 if (!cast)
|
|
|
786 cast = CT_NO_CAST;
|
|
|
787
|
|
|
788 return cast;
|
|
|
789 }
|
|
|
790
|
|
|
791
|
|
|
792 typedef struct cast
|
|
|
793 {
|
|
|
794 int type;
|
|
|
795 gimple stmt;
|
|
|
796 } cast_t;
|
|
|
797
|
|
|
798 /* This function is a callback for walk_use_def_chains function called
|
|
|
799 from is_array_access_through_pointer_and_index. */
|
|
|
800
|
|
|
801 static bool
|
|
|
802 is_cast_from_non_pointer (tree var, gimple def_stmt, void *data)
|
|
|
803 {
|
|
|
804 if (!def_stmt || !var)
|
|
|
805 return false;
|
|
|
806
|
|
|
807 if (gimple_code (def_stmt) == GIMPLE_PHI)
|
|
|
808 return false;
|
|
|
809
|
|
|
810 if (SSA_NAME_IS_DEFAULT_DEF (var))
|
|
|
811 return false;
|
|
|
812
|
|
|
813 if (is_gimple_assign (def_stmt))
|
|
|
814 {
|
|
|
815 use_operand_p use_p;
|
|
|
816 ssa_op_iter iter;
|
|
|
817 unsigned int cast = look_for_casts_stmt (def_stmt);
|
|
|
818
|
|
|
819 /* Check that only one cast happened, and it's of non-pointer
|
|
|
820 type. */
|
|
|
821 if ((cast & CT_FROM_NON_P) == (CT_FROM_NON_P)
|
|
|
822 && (cast & ~(CT_FROM_NON_P)) == 0)
|
|
|
823 {
|
|
|
824 ((cast_t *)data)->stmt = def_stmt;
|
|
|
825 ((cast_t *)data)->type++;
|
|
|
826
|
|
|
827 FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES)
|
|
|
828 {
|
|
|
829 walk_use_def_chains (USE_FROM_PTR (use_p),
|
|
|
830 is_cast_from_non_pointer, data, false);
|
|
|
831 if (((cast_t*)data)->type == -1)
|
|
|
832 break;
|
|
|
833 }
|
|
|
834 }
|
|
|
835 /* Check that there is no cast, or cast is not harmful. */
|
|
|
836 else if ((cast & CT_NO_CAST) == (CT_NO_CAST)
|
|
|
837 || (cast & CT_DOWN) == (CT_DOWN)
|
|
|
838 || (cast & CT_UP) == (CT_UP)
|
|
|
839 || (cast & CT_USELESS) == (CT_USELESS)
|
|
|
840 || (cast & CT_FROM_MALLOC) == (CT_FROM_MALLOC))
|
|
|
841 {
|
|
|
842 FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES)
|
|
|
843 {
|
|
|
844 walk_use_def_chains (USE_FROM_PTR (use_p),
|
|
|
845 is_cast_from_non_pointer, data, false);
|
|
|
846 if (((cast_t*)data)->type == -1)
|
|
|
847 break;
|
|
|
848 }
|
|
|
849 }
|
|
|
850 /* The cast is harmful. */
|
|
|
851 else
|
|
|
852 ((cast_t *)data)->type = -1;
|
|
|
853 }
|
|
|
854
|
|
|
855 if (((cast_t*)data)->type == -1)
|
|
|
856 return true;
|
|
|
857
|
|
|
858 return false;
|
|
|
859 }
|
|
|
860
|
|
|
861 /* When array element a_p[i] is accessed through the pointer a_p
|
|
|
862 and index i, it's translated into the following sequence
|
|
|
863 in gimple:
|
|
|
864
|
|
|
865 i.1_5 = (unsigned int) i_1;
|
|
|
866 D.1605_6 = i.1_5 * 16;
|
|
|
867 D.1606_7 = (struct str_t *) D.1605_6;
|
|
|
868 a_p.2_8 = a_p;
|
|
|
869 D.1608_9 = D.1606_7 + a_p.2_8;
|
|
|
870
|
|
|
871 OP0 and OP1 are of the same pointer types and stand for
|
|
|
872 D.1606_7 and a_p.2_8 or vise versa.
|
|
|
873
|
|
|
874 This function checks that:
|
|
|
875
|
|
|
876 1. one of OP0 and OP1 (D.1606_7) has passed only one cast from
|
|
|
877 non-pointer type (D.1606_7 = (struct str_t *) D.1605_6;).
|
|
|
878
|
|
|
879 2. one of OP0 and OP1 which has passed the cast from
|
|
|
880 non-pointer type (D.1606_7), is actually generated by multiplication of
|
|
|
881 index by size of type to which both OP0 and OP1 point to
|
|
|
882 (in this case D.1605_6 = i.1_5 * 16; ).
|
|
|
883
|
|
|
884 3. an address of def of the var to which was made cast (D.1605_6)
|
|
|
885 was not taken.(How can it happen?)
|
|
|
886
|
|
|
887 The following items are checked implicitly by the end of algorithm:
|
|
|
888
|
|
|
889 4. one of OP0 and OP1 (a_p.2_8) have never been cast
|
|
|
890 (because if it was cast to pointer type, its type, that is also
|
|
|
891 the type of OP0 and OP1, will be marked as escaped during
|
|
|
892 analysis of casting stmt (when check_cast() is called
|
|
|
893 from scan_for_refs for this stmt)).
|
|
|
894
|
|
|
895 5. defs of OP0 and OP1 are not passed into externally visible function
|
|
|
896 (because if they are passed then their type, that is also the type of OP0
|
|
|
897 and OP1, will be marked and escaped during check_call function called from
|
|
|
898 scan_for_refs with call stmt).
|
|
|
899
|
|
|
900 In total, 1-5 guaranty that it's an access to array by pointer and index.
|
|
|
901
|
|
|
902 */
|
|
|
903
|
|
|
904 bool
|
|
|
905 is_array_access_through_pointer_and_index (enum tree_code code, tree op0,
|
|
|
906 tree op1, tree *base, tree *offset,
|
|
|
907 gimple *offset_cast_stmt)
|
|
|
908 {
|
|
|
909 tree before_cast;
|
|
|
910 gimple before_cast_def_stmt;
|
|
|
911 cast_t op0_cast, op1_cast;
|
|
|
912
|
|
|
913 *base = NULL;
|
|
|
914 *offset = NULL;
|
|
|
915 *offset_cast_stmt = NULL;
|
|
|
916
|
|
|
917 /* Check 1. */
|
|
|
918 if (code == POINTER_PLUS_EXPR)
|
|
|
919 {
|
|
|
920 tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0));
|
|
|
921 tree op1type = TYPE_MAIN_VARIANT (TREE_TYPE (op1));
|
|
|
922
|
|
|
923 /* One of op0 and op1 is of pointer type and the other is numerical. */
|
|
|
924 if (POINTER_TYPE_P (op0type) && NUMERICAL_TYPE_CHECK (op1type))
|
|
|
925 {
|
|
|
926 *base = op0;
|
|
|
927 *offset = op1;
|
|
|
928 }
|
|
|
929 else if (POINTER_TYPE_P (op1type) && NUMERICAL_TYPE_CHECK (op0type))
|
|
|
930 {
|
|
|
931 *base = op1;
|
|
|
932 *offset = op0;
|
|
|
933 }
|
|
|
934 else
|
|
|
935 return false;
|
|
|
936 }
|
|
|
937 else
|
|
|
938 {
|
|
|
939 /* Init data for walk_use_def_chains function. */
|
|
|
940 op0_cast.type = op1_cast.type = 0;
|
|
|
941 op0_cast.stmt = op1_cast.stmt = NULL;
|
|
|
942
|
|
|
943 visited_stmts = pointer_set_create ();
|
|
|
944 walk_use_def_chains (op0, is_cast_from_non_pointer,(void *)(&op0_cast),
|
|
|
945 false);
|
|
|
946 pointer_set_destroy (visited_stmts);
|
|
|
947
|
|
|
948 visited_stmts = pointer_set_create ();
|
|
|
949 walk_use_def_chains (op1, is_cast_from_non_pointer,(void *)(&op1_cast),
|
|
|
950 false);
|
|
|
951 pointer_set_destroy (visited_stmts);
|
|
|
952
|
|
|
953 if (op0_cast.type == 1 && op1_cast.type == 0)
|
|
|
954 {
|
|
|
955 *base = op1;
|
|
|
956 *offset = op0;
|
|
|
957 *offset_cast_stmt = op0_cast.stmt;
|
|
|
958 }
|
|
|
959 else if (op0_cast.type == 0 && op1_cast.type == 1)
|
|
|
960 {
|
|
|
961 *base = op0;
|
|
|
962 *offset = op1;
|
|
|
963 *offset_cast_stmt = op1_cast.stmt;
|
|
|
964 }
|
|
|
965 else
|
|
|
966 return false;
|
|
|
967 }
|
|
|
968
|
|
|
969 /* Check 2.
|
|
|
970 offset_cast_stmt is of the form:
|
|
|
971 D.1606_7 = (struct str_t *) D.1605_6; */
|
|
|
972
|
|
|
973 if (*offset_cast_stmt)
|
|
|
974 {
|
|
|
975 before_cast = SINGLE_SSA_TREE_OPERAND (*offset_cast_stmt, SSA_OP_USE);
|
|
|
976 if (!before_cast)
|
|
|
977 return false;
|
|
|
978
|
|
|
979 if (SSA_NAME_IS_DEFAULT_DEF (before_cast))
|
|
|
980 return false;
|
|
|
981
|
|
|
982 before_cast_def_stmt = SSA_NAME_DEF_STMT (before_cast);
|
|
|
983 if (!before_cast_def_stmt)
|
|
|
984 return false;
|
|
|
985 }
|
|
|
986 else
|
|
|
987 before_cast_def_stmt = SSA_NAME_DEF_STMT (*offset);
|
|
|
988
|
|
|
989 /* before_cast_def_stmt should be of the form:
|
|
|
990 D.1605_6 = i.1_5 * 16; */
|
|
|
991
|
|
|
992 if (is_gimple_assign (before_cast_def_stmt))
|
|
|
993 {
|
|
|
994 /* We expect temporary here. */
|
|
|
995 if (!is_gimple_reg (gimple_assign_lhs (before_cast_def_stmt)))
|
|
|
996 return false;
|
|
|
997
|
|
|
998 if (gimple_assign_rhs_code (before_cast_def_stmt) == MULT_EXPR)
|
|
|
999 {
|
|
|
1000 tree arg0 = gimple_assign_rhs1 (before_cast_def_stmt);
|
|
|
1001 tree arg1 = gimple_assign_rhs2 (before_cast_def_stmt);
|
|
|
1002 tree unit_size =
|
|
|
1003 TYPE_SIZE_UNIT (TREE_TYPE (TYPE_MAIN_VARIANT (TREE_TYPE (op0))));
|
|
|
1004
|
|
|
1005 if (!(CONSTANT_CLASS_P (arg0)
|
|
|
1006 && simple_cst_equal (arg0, unit_size))
|
|
|
1007 && !(CONSTANT_CLASS_P (arg1)
|
|
|
1008 && simple_cst_equal (arg1, unit_size)))
|
|
|
1009 return false;
|
|
|
1010 }
|
|
|
1011 else
|
|
|
1012 return false;
|
|
|
1013 }
|
|
|
1014 else
|
|
|
1015 return false;
|
|
|
1016
|
|
|
1017 /* Check 3.
|
|
|
1018 check that address of D.1605_6 was not taken.
|
|
|
1019 FIXME: if D.1605_6 is gimple reg than it cannot be addressable. */
|
|
|
1020
|
|
|
1021 return true;
|
|
|
1022 }
|
|
|
1023
|
|
|
1024 /* Register the parameter and return types of function FN. The type
|
|
|
1025 ESCAPES if the function is visible outside of the compilation
|
|
|
1026 unit. */
|
|
|
1027 static void
|
|
|
1028 check_function_parameter_and_return_types (tree fn, bool escapes)
|
|
|
1029 {
|
|
|
1030 tree arg;
|
|
|
1031
|
|
|
1032 if (TYPE_ARG_TYPES (TREE_TYPE (fn)))
|
|
|
1033 {
|
|
|
1034 for (arg = TYPE_ARG_TYPES (TREE_TYPE (fn));
|
|
|
1035 arg && TREE_VALUE (arg) != void_type_node;
|
|
|
1036 arg = TREE_CHAIN (arg))
|
|
|
1037 {
|
|
|
1038 tree type = get_canon_type (TREE_VALUE (arg), false, false);
|
|
|
1039 if (escapes)
|
|
|
1040 mark_interesting_type (type, EXPOSED_PARAMETER);
|
|
|
1041 }
|
|
|
1042 }
|
|
|
1043 else
|
|
|
1044 {
|
|
|
1045 /* FIXME - According to Geoff Keating, we should never have to
|
|
|
1046 do this; the front ends should always process the arg list
|
|
|
1047 from the TYPE_ARG_LIST. However, Geoff is wrong, this code
|
|
|
1048 does seem to be live. */
|
|
|
1049
|
|
|
1050 for (arg = DECL_ARGUMENTS (fn); arg; arg = TREE_CHAIN (arg))
|
|
|
1051 {
|
|
|
1052 tree type = get_canon_type (TREE_TYPE (arg), false, false);
|
|
|
1053 if (escapes)
|
|
|
1054 mark_interesting_type (type, EXPOSED_PARAMETER);
|
|
|
1055 }
|
|
|
1056 }
|
|
|
1057 if (escapes)
|
|
|
1058 {
|
|
|
1059 tree type = get_canon_type (TREE_TYPE (TREE_TYPE (fn)), false, false);
|
|
|
1060 mark_interesting_type (type, EXPOSED_PARAMETER);
|
|
|
1061 }
|
|
|
1062 }
|
|
|
1063
|
|
|
1064 /* Return true if the variable T is the right kind of static variable to
|
|
|
1065 perform compilation unit scope escape analysis. */
|
|
|
1066
|
|
|
1067 static inline void
|
|
|
1068 has_proper_scope_for_analysis (tree t)
|
|
|
1069 {
|
|
|
1070 /* If the variable has the "used" attribute, treat it as if it had a
|
|
|
1071 been touched by the devil. */
|
|
|
1072 tree type = get_canon_type (TREE_TYPE (t), false, false);
|
|
|
1073 if (!type) return;
|
|
|
1074
|
|
|
1075 if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
|
|
|
1076 {
|
|
|
1077 mark_interesting_type (type, FULL_ESCAPE);
|
|
|
1078 return;
|
|
|
1079 }
|
|
|
1080
|
|
|
1081 /* Do not want to do anything with volatile except mark any
|
|
|
1082 function that uses one to be not const or pure. */
|
|
|
1083 if (TREE_THIS_VOLATILE (t))
|
|
|
1084 return;
|
|
|
1085
|
|
|
1086 /* Do not care about a local automatic that is not static. */
|
|
|
1087 if (!TREE_STATIC (t) && !DECL_EXTERNAL (t))
|
|
|
1088 return;
|
|
|
1089
|
|
|
1090 if (DECL_EXTERNAL (t) || TREE_PUBLIC (t))
|
|
|
1091 {
|
|
|
1092 /* If the front end set the variable to be READONLY and
|
|
|
1093 constant, we can allow this variable in pure or const
|
|
|
1094 functions but the scope is too large for our analysis to set
|
|
|
1095 these bits ourselves. */
|
|
|
1096
|
|
|
1097 if (TREE_READONLY (t)
|
|
|
1098 && DECL_INITIAL (t)
|
|
|
1099 && is_gimple_min_invariant (DECL_INITIAL (t)))
|
|
|
1100 ; /* Read of a constant, do not change the function state. */
|
|
|
1101 else
|
|
|
1102 {
|
|
|
1103 /* The type escapes for all public and externs. */
|
|
|
1104 mark_interesting_type (type, FULL_ESCAPE);
|
|
|
1105 }
|
|
|
1106 }
|
|
|
1107 }
|
|
|
1108
|
|
|
1109 /* If T is a VAR_DECL for a static that we are interested in, add the
|
|
|
1110 uid to the bitmap. */
|
|
|
1111
|
|
|
1112 static void
|
|
|
1113 check_operand (tree t)
|
|
|
1114 {
|
|
|
1115 if (!t) return;
|
|
|
1116
|
|
|
1117 /* This is an assignment from a function, register the types as
|
|
|
1118 escaping. */
|
|
|
1119 if (TREE_CODE (t) == FUNCTION_DECL)
|
|
|
1120 check_function_parameter_and_return_types (t, true);
|
|
|
1121
|
|
|
1122 else if (TREE_CODE (t) == VAR_DECL)
|
|
|
1123 has_proper_scope_for_analysis (t);
|
|
|
1124 }
|
|
|
1125
|
|
|
1126 /* Examine tree T for references. */
|
|
|
1127
|
|
|
1128 static void
|
|
|
1129 check_tree (tree t)
|
|
|
1130 {
|
|
|
1131 if ((TREE_CODE (t) == EXC_PTR_EXPR) || (TREE_CODE (t) == FILTER_EXPR))
|
|
|
1132 return;
|
|
|
1133
|
|
|
1134 /* We want to catch here also REALPART_EXPR and IMAGEPART_EXPR,
|
|
|
1135 but they already included in handled_component_p. */
|
|
|
1136 while (handled_component_p (t))
|
|
|
1137 {
|
|
|
1138 if (TREE_CODE (t) == ARRAY_REF)
|
|
|
1139 check_operand (TREE_OPERAND (t, 1));
|
|
|
1140 t = TREE_OPERAND (t, 0);
|
|
|
1141 }
|
|
|
1142
|
|
|
1143 if (INDIRECT_REF_P (t))
|
|
|
1144 /* || TREE_CODE (t) == MEM_REF) */
|
|
|
1145 check_tree (TREE_OPERAND (t, 0));
|
|
|
1146
|
|
|
1147 if (SSA_VAR_P (t) || (TREE_CODE (t) == FUNCTION_DECL))
|
|
|
1148 {
|
|
|
1149 check_operand (t);
|
|
|
1150 if (DECL_P (t) && DECL_INITIAL (t))
|
|
|
1151 check_tree (DECL_INITIAL (t));
|
|
|
1152 }
|
|
|
1153 }
|
|
|
1154
|
|
|
1155 /* Create an address_of edge FROM_TYPE.TO_TYPE. */
|
|
|
1156 static void
|
|
|
1157 mark_interesting_addressof (tree to_type, tree from_type)
|
|
|
1158 {
|
|
|
1159 int from_uid;
|
|
|
1160 int to_uid;
|
|
|
1161 bitmap type_map;
|
|
|
1162 splay_tree_node result;
|
|
|
1163
|
|
|
1164 from_type = get_canon_type (from_type, false, false);
|
|
|
1165 to_type = get_canon_type (to_type, false, false);
|
|
|
1166
|
|
|
1167 if (!from_type || !to_type)
|
|
|
1168 return;
|
|
|
1169
|
|
|
1170 from_uid = TYPE_UID (from_type);
|
|
|
1171 to_uid = TYPE_UID (to_type);
|
|
|
1172
|
|
|
1173 gcc_assert (ipa_type_escape_star_count_of_interesting_type (from_type) == 0);
|
|
|
1174
|
|
|
1175 /* Process the Y into X map pointer. */
|
|
|
1176 result = splay_tree_lookup (uid_to_addressof_down_map,
|
|
|
1177 (splay_tree_key) from_uid);
|
|
|
1178
|
|
|
1179 if (result)
|
|
|
1180 type_map = (bitmap) result->value;
|
|
|
1181 else
|
|
|
1182 {
|
|
|
1183 type_map = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1184 splay_tree_insert (uid_to_addressof_down_map,
|
|
|
1185 from_uid,
|
|
|
1186 (splay_tree_value)type_map);
|
|
|
1187 }
|
|
|
1188 bitmap_set_bit (type_map, TYPE_UID (to_type));
|
|
|
1189
|
|
|
1190 /* Process the X into Y reverse map pointer. */
|
|
|
1191 result =
|
|
|
1192 splay_tree_lookup (uid_to_addressof_up_map, (splay_tree_key) to_uid);
|
|
|
1193
|
|
|
1194 if (result)
|
|
|
1195 type_map = (bitmap) result->value;
|
|
|
1196 else
|
|
|
1197 {
|
|
|
1198 type_map = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1199 splay_tree_insert (uid_to_addressof_up_map,
|
|
|
1200 to_uid,
|
|
|
1201 (splay_tree_value)type_map);
|
|
|
1202 }
|
|
|
1203 bitmap_set_bit (type_map, TYPE_UID (from_type));
|
|
|
1204 }
|
|
|
1205
|
|
|
1206 /* Scan tree T to see if there are any addresses taken in within T. */
|
|
|
1207
|
|
|
1208 static void
|
|
|
1209 look_for_address_of (tree t)
|
|
|
1210 {
|
|
|
1211 if (TREE_CODE (t) == ADDR_EXPR)
|
|
|
1212 {
|
|
|
1213 tree x = get_base_var (t);
|
|
|
1214 tree cref = TREE_OPERAND (t, 0);
|
|
|
1215
|
|
|
1216 /* If we have an expression of the form "&a.b.c.d", mark a.b,
|
|
|
1217 b.c and c.d. as having its address taken. */
|
|
|
1218 tree fielddecl = NULL_TREE;
|
|
|
1219 while (cref!= x)
|
|
|
1220 {
|
|
|
1221 if (TREE_CODE (cref) == COMPONENT_REF)
|
|
|
1222 {
|
|
|
1223 fielddecl = TREE_OPERAND (cref, 1);
|
|
|
1224 mark_interesting_addressof (TREE_TYPE (fielddecl),
|
|
|
1225 DECL_FIELD_CONTEXT (fielddecl));
|
|
|
1226 }
|
|
|
1227 else if (TREE_CODE (cref) == ARRAY_REF)
|
|
|
1228 get_canon_type (TREE_TYPE (cref), false, false);
|
|
|
1229
|
|
|
1230 cref = TREE_OPERAND (cref, 0);
|
|
|
1231 }
|
|
|
1232
|
|
|
1233 if (TREE_CODE (x) == VAR_DECL)
|
|
|
1234 has_proper_scope_for_analysis (x);
|
|
|
1235 }
|
|
|
1236 }
|
|
|
1237
|
|
|
1238
|
|
|
1239 /* Scan tree T to see if there are any casts within it. */
|
|
|
1240
|
|
|
1241 static unsigned int
|
|
|
1242 look_for_casts (tree t)
|
|
|
1243 {
|
|
|
1244 unsigned int cast = 0;
|
|
|
1245
|
|
|
1246 if (is_gimple_cast (t) || TREE_CODE (t) == VIEW_CONVERT_EXPR)
|
|
|
1247 {
|
|
|
1248 tree castfromvar = TREE_OPERAND (t, 0);
|
|
|
1249 cast = cast | check_cast (TREE_TYPE (t), castfromvar);
|
|
|
1250 }
|
|
|
1251 else
|
|
|
1252 while (handled_component_p (t))
|
|
|
1253 {
|
|
|
1254 t = TREE_OPERAND (t, 0);
|
|
|
1255 if (TREE_CODE (t) == VIEW_CONVERT_EXPR)
|
|
|
1256 {
|
|
|
1257 /* This may be some part of a component ref.
|
|
|
1258 IE it may be a.b.VIEW_CONVERT_EXPR<weird_type>(c).d, AFAIK.
|
|
|
1259 castfromref will give you a.b.c, not a. */
|
|
|
1260 tree castfromref = TREE_OPERAND (t, 0);
|
|
|
1261 cast = cast | check_cast (TREE_TYPE (t), castfromref);
|
|
|
1262 }
|
|
|
1263 else if (TREE_CODE (t) == COMPONENT_REF)
|
|
|
1264 get_canon_type (TREE_TYPE (TREE_OPERAND (t, 1)), false, false);
|
|
|
1265 }
|
|
|
1266
|
|
|
1267 if (!cast)
|
|
|
1268 cast = CT_NO_CAST;
|
|
|
1269 return cast;
|
|
|
1270 }
|
|
|
1271
|
|
|
1272 /* Check to see if T is a read or address of operation on a static var
|
|
|
1273 we are interested in analyzing. */
|
|
|
1274
|
|
|
1275 static void
|
|
|
1276 check_rhs_var (tree t)
|
|
|
1277 {
|
|
|
1278 look_for_address_of (t);
|
|
|
1279 check_tree (t);
|
|
|
1280 }
|
|
|
1281
|
|
|
1282 /* Check to see if T is an assignment to a static var we are
|
|
|
1283 interested in analyzing. */
|
|
|
1284
|
|
|
1285 static void
|
|
|
1286 check_lhs_var (tree t)
|
|
|
1287 {
|
|
|
1288 check_tree (t);
|
|
|
1289 }
|
|
|
1290
|
|
|
1291 /* This is a scaled down version of get_asm_expr_operands from
|
|
|
1292 tree_ssa_operands.c. The version there runs much later and assumes
|
|
|
1293 that aliasing information is already available. Here we are just
|
|
|
1294 trying to find if the set of inputs and outputs contain references
|
|
|
1295 or address of operations to local. FN is the function being
|
|
|
1296 analyzed and STMT is the actual asm statement. */
|
|
|
1297
|
|
|
1298 static void
|
|
|
1299 check_asm (gimple stmt)
|
|
|
1300 {
|
|
|
1301 size_t i;
|
|
|
1302
|
|
|
1303 for (i = 0; i < gimple_asm_noutputs (stmt); i++)
|
|
|
1304 check_lhs_var (gimple_asm_output_op (stmt, i));
|
|
|
1305
|
|
|
1306 for (i = 0; i < gimple_asm_ninputs (stmt); i++)
|
|
|
1307 check_rhs_var (gimple_asm_input_op (stmt, i));
|
|
|
1308
|
|
|
1309 /* There is no code here to check for asm memory clobbers. The
|
|
|
1310 casual maintainer might think that such code would be necessary,
|
|
|
1311 but that appears to be wrong. In other parts of the compiler,
|
|
|
1312 the asm memory clobbers are assumed to only clobber variables
|
|
|
1313 that are addressable. All types with addressable instances are
|
|
|
1314 assumed to already escape. So, we are protected here. */
|
|
|
1315 }
|
|
|
1316
|
|
|
1317
|
|
|
1318 /* Check the parameters of function call to CALL to mark the
|
|
|
1319 types that pass across the function boundary. Also check to see if
|
|
|
1320 this is either an indirect call, a call outside the compilation
|
|
|
1321 unit. */
|
|
|
1322
|
|
|
1323 static void
|
|
|
1324 check_call (gimple call)
|
|
|
1325 {
|
|
|
1326 tree callee_t = gimple_call_fndecl (call);
|
|
|
1327 struct cgraph_node* callee;
|
|
|
1328 enum availability avail = AVAIL_NOT_AVAILABLE;
|
|
|
1329 size_t i;
|
|
|
1330
|
|
|
1331 for (i = 0; i < gimple_call_num_args (call); i++)
|
|
|
1332 check_rhs_var (gimple_call_arg (call, i));
|
|
|
1333
|
|
|
1334 if (callee_t)
|
|
|
1335 {
|
|
|
1336 tree arg_type;
|
|
|
1337 tree last_arg_type = NULL;
|
|
|
1338 callee = cgraph_node(callee_t);
|
|
|
1339 avail = cgraph_function_body_availability (callee);
|
|
|
1340
|
|
|
1341 /* Check that there are no implicit casts in the passing of
|
|
|
1342 parameters. */
|
|
|
1343 if (TYPE_ARG_TYPES (TREE_TYPE (callee_t)))
|
|
|
1344 {
|
|
|
1345 for (arg_type = TYPE_ARG_TYPES (TREE_TYPE (callee_t)), i = 0;
|
|
|
1346 arg_type && TREE_VALUE (arg_type) != void_type_node;
|
|
|
1347 arg_type = TREE_CHAIN (arg_type), i++)
|
|
|
1348 {
|
|
|
1349 tree operand = gimple_call_arg (call, i);
|
|
|
1350 if (operand)
|
|
|
1351 {
|
|
|
1352 last_arg_type = TREE_VALUE(arg_type);
|
|
|
1353 check_cast (last_arg_type, operand);
|
|
|
1354 }
|
|
|
1355 else
|
|
|
1356 /* The code reaches here for some unfortunate
|
|
|
1357 builtin functions that do not have a list of
|
|
|
1358 argument types. */
|
|
|
1359 break;
|
|
|
1360 }
|
|
|
1361 }
|
|
|
1362 else
|
|
|
1363 {
|
|
|
1364 /* FIXME - According to Geoff Keating, we should never
|
|
|
1365 have to do this; the front ends should always process
|
|
|
1366 the arg list from the TYPE_ARG_LIST. */
|
|
|
1367 for (arg_type = DECL_ARGUMENTS (callee_t), i = 0;
|
|
|
1368 arg_type;
|
|
|
1369 arg_type = TREE_CHAIN (arg_type), i++)
|
|
|
1370 {
|
|
|
1371 tree operand = gimple_call_arg (call, i);
|
|
|
1372 if (operand)
|
|
|
1373 {
|
|
|
1374 last_arg_type = TREE_TYPE (arg_type);
|
|
|
1375 check_cast (last_arg_type, operand);
|
|
|
1376 }
|
|
|
1377 else
|
|
|
1378 /* The code reaches here for some unfortunate
|
|
|
1379 builtin functions that do not have a list of
|
|
|
1380 argument types. */
|
|
|
1381 break;
|
|
|
1382 }
|
|
|
1383 }
|
|
|
1384
|
|
|
1385 /* In the case where we have a var_args function, we need to
|
|
|
1386 check the remaining parameters against the last argument. */
|
|
|
1387 arg_type = last_arg_type;
|
|
|
1388 for ( ; i < gimple_call_num_args (call); i++)
|
|
|
1389 {
|
|
|
1390 tree operand = gimple_call_arg (call, i);
|
|
|
1391 if (arg_type)
|
|
|
1392 check_cast (arg_type, operand);
|
|
|
1393 else
|
|
|
1394 {
|
|
|
1395 /* The code reaches here for some unfortunate
|
|
|
1396 builtin functions that do not have a list of
|
|
|
1397 argument types. Most of these functions have
|
|
|
1398 been marked as having their parameters not
|
|
|
1399 escape, but for the rest, the type is doomed. */
|
|
|
1400 tree type = get_canon_type (TREE_TYPE (operand), false, false);
|
|
|
1401 mark_interesting_type (type, FULL_ESCAPE);
|
|
|
1402 }
|
|
|
1403 }
|
|
|
1404 }
|
|
|
1405
|
|
|
1406 /* The callee is either unknown (indirect call) or there is just no
|
|
|
1407 scannable code for it (external call) . We look to see if there
|
|
|
1408 are any bits available for the callee (such as by declaration or
|
|
|
1409 because it is builtin) and process solely on the basis of those
|
|
|
1410 bits. */
|
|
|
1411 if (avail == AVAIL_NOT_AVAILABLE || avail == AVAIL_OVERWRITABLE)
|
|
|
1412 {
|
|
|
1413 /* If this is a direct call to an external function, mark all of
|
|
|
1414 the parameter and return types. */
|
|
|
1415 for (i = 0; i < gimple_call_num_args (call); i++)
|
|
|
1416 {
|
|
|
1417 tree operand = gimple_call_arg (call, i);
|
|
|
1418 tree type = get_canon_type (TREE_TYPE (operand), false, false);
|
|
|
1419 mark_interesting_type (type, EXPOSED_PARAMETER);
|
|
|
1420 }
|
|
|
1421
|
|
|
1422 if (callee_t)
|
|
|
1423 {
|
|
|
1424 tree type =
|
|
|
1425 get_canon_type (TREE_TYPE (TREE_TYPE (callee_t)), false, false);
|
|
|
1426 mark_interesting_type (type, EXPOSED_PARAMETER);
|
|
|
1427 }
|
|
|
1428 }
|
|
|
1429 }
|
|
|
1430
|
|
|
1431 /* CODE is the operation on OP0 and OP1. OP0 is the operand that we
|
|
|
1432 *know* is a pointer type. OP1 may be a pointer type. */
|
|
|
1433 static bool
|
|
|
1434 okay_pointer_operation (enum tree_code code, tree op0, tree op1)
|
|
|
1435 {
|
|
|
1436 tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0));
|
|
|
1437
|
|
|
1438 switch (code)
|
|
|
1439 {
|
|
|
1440 case MULT_EXPR:
|
|
|
1441 /* Multiplication does not change alignment. */
|
|
|
1442 return true;
|
|
|
1443 break;
|
|
|
1444 case MINUS_EXPR:
|
|
|
1445 case PLUS_EXPR:
|
|
|
1446 case POINTER_PLUS_EXPR:
|
|
|
1447 {
|
|
|
1448 tree base, offset;
|
|
|
1449 gimple offset_cast_stmt;
|
|
|
1450
|
|
|
1451 if (POINTER_TYPE_P (op0type)
|
|
|
1452 && TREE_CODE (op0) == SSA_NAME
|
|
|
1453 && TREE_CODE (op1) == SSA_NAME
|
|
|
1454 && is_array_access_through_pointer_and_index (code, op0, op1,
|
|
|
1455 &base,
|
|
|
1456 &offset,
|
|
|
1457 &offset_cast_stmt))
|
|
|
1458 return true;
|
|
|
1459 else
|
|
|
1460 {
|
|
|
1461 tree size_of_op0_points_to = TYPE_SIZE_UNIT (TREE_TYPE (op0type));
|
|
|
1462
|
|
|
1463 if (CONSTANT_CLASS_P (op1)
|
|
|
1464 && size_of_op0_points_to
|
|
|
1465 && multiple_of_p (TREE_TYPE (size_of_op0_points_to),
|
|
|
1466 op1, size_of_op0_points_to))
|
|
|
1467 return true;
|
|
|
1468
|
|
|
1469 if (CONSTANT_CLASS_P (op0)
|
|
|
1470 && size_of_op0_points_to
|
|
|
1471 && multiple_of_p (TREE_TYPE (size_of_op0_points_to),
|
|
|
1472 op0, size_of_op0_points_to))
|
|
|
1473 return true;
|
|
|
1474 }
|
|
|
1475 }
|
|
|
1476 break;
|
|
|
1477 default:
|
|
|
1478 return false;
|
|
|
1479 }
|
|
|
1480 return false;
|
|
|
1481 }
|
|
|
1482
|
|
|
1483
|
|
|
1484
|
|
|
1485 /* Helper for scan_for_refs. Check the operands of an assignment to
|
|
|
1486 mark types that may escape. */
|
|
|
1487
|
|
|
1488 static void
|
|
|
1489 check_assign (gimple t)
|
|
|
1490 {
|
|
|
1491 /* First look on the lhs and see what variable is stored to */
|
|
|
1492 check_lhs_var (gimple_assign_lhs (t));
|
|
|
1493
|
|
|
1494 /* For the purposes of figuring out what the cast affects */
|
|
|
1495
|
|
|
1496 /* Next check the operands on the rhs to see if they are ok. */
|
|
|
1497 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (t)))
|
|
|
1498 {
|
|
|
1499 case tcc_binary:
|
|
|
1500 {
|
|
|
1501 tree op0 = gimple_assign_rhs1 (t);
|
|
|
1502 tree type0 = get_canon_type (TREE_TYPE (op0), false, false);
|
|
|
1503 tree op1 = gimple_assign_rhs2 (t);
|
|
|
1504 tree type1 = get_canon_type (TREE_TYPE (op1), false, false);
|
|
|
1505
|
|
|
1506 /* If this is pointer arithmetic of any bad sort, then
|
|
|
1507 we need to mark the types as bad. For binary
|
|
|
1508 operations, no binary operator we currently support
|
|
|
1509 is always "safe" in regard to what it would do to
|
|
|
1510 pointers for purposes of determining which types
|
|
|
1511 escape, except operations of the size of the type.
|
|
|
1512 It is possible that min and max under the right set
|
|
|
1513 of circumstances and if the moon is in the correct
|
|
|
1514 place could be safe, but it is hard to see how this
|
|
|
1515 is worth the effort. */
|
|
|
1516 if (type0 && POINTER_TYPE_P (type0)
|
|
|
1517 && !okay_pointer_operation (gimple_assign_rhs_code (t), op0, op1))
|
|
|
1518 mark_interesting_type (type0, FULL_ESCAPE);
|
|
|
1519
|
|
|
1520 if (type1 && POINTER_TYPE_P (type1)
|
|
|
1521 && !okay_pointer_operation (gimple_assign_rhs_code (t), op1, op0))
|
|
|
1522 mark_interesting_type (type1, FULL_ESCAPE);
|
|
|
1523
|
|
|
1524 look_for_casts (op0);
|
|
|
1525 look_for_casts (op1);
|
|
|
1526 check_rhs_var (op0);
|
|
|
1527 check_rhs_var (op1);
|
|
|
1528 }
|
|
|
1529 break;
|
|
|
1530
|
|
|
1531 case tcc_unary:
|
|
|
1532 {
|
|
|
1533 tree op0 = gimple_assign_rhs1 (t);
|
|
|
1534 tree type0 = get_canon_type (TREE_TYPE (op0), false, false);
|
|
|
1535
|
|
|
1536 /* For unary operations, if the operation is NEGATE or ABS on
|
|
|
1537 a pointer, this is also considered pointer arithmetic and
|
|
|
1538 thus, bad for business. */
|
|
|
1539 if (type0
|
|
|
1540 && POINTER_TYPE_P (type0)
|
|
|
1541 && (TREE_CODE (op0) == NEGATE_EXPR
|
|
|
1542 || TREE_CODE (op0) == ABS_EXPR))
|
|
|
1543 mark_interesting_type (type0, FULL_ESCAPE);
|
|
|
1544
|
|
|
1545 check_rhs_var (op0);
|
|
|
1546 look_for_casts (op0);
|
|
|
1547 }
|
|
|
1548 break;
|
|
|
1549
|
|
|
1550 case tcc_reference:
|
|
|
1551 look_for_casts (gimple_assign_rhs1 (t));
|
|
|
1552 check_rhs_var (gimple_assign_rhs1 (t));
|
|
|
1553 break;
|
|
|
1554
|
|
|
1555 case tcc_declaration:
|
|
|
1556 check_rhs_var (gimple_assign_rhs1 (t));
|
|
|
1557 break;
|
|
|
1558
|
|
|
1559 case tcc_expression:
|
|
|
1560 if (gimple_assign_rhs_code (t) == ADDR_EXPR)
|
|
|
1561 {
|
|
|
1562 tree rhs = gimple_assign_rhs1 (t);
|
|
|
1563 look_for_casts (TREE_OPERAND (rhs, 0));
|
|
|
1564 check_rhs_var (rhs);
|
|
|
1565 }
|
|
|
1566 break;
|
|
|
1567
|
|
|
1568 default:
|
|
|
1569 break;
|
|
|
1570 }
|
|
|
1571 }
|
|
|
1572
|
|
|
1573
|
|
|
1574 /* Scan statement T for references to types and mark anything
|
|
|
1575 interesting. */
|
|
|
1576
|
|
|
1577 static void
|
|
|
1578 scan_for_refs (gimple t)
|
|
|
1579 {
|
|
|
1580 switch (gimple_code (t))
|
|
|
1581 {
|
|
|
1582 case GIMPLE_ASSIGN:
|
|
|
1583 check_assign (t);
|
|
|
1584 break;
|
|
|
1585
|
|
|
1586 case GIMPLE_CALL:
|
|
|
1587 /* If this is a call to malloc, squirrel away the result so we
|
|
|
1588 do mark the resulting cast as being bad. */
|
|
|
1589 check_call (t);
|
|
|
1590 break;
|
|
|
1591
|
|
|
1592 case GIMPLE_ASM:
|
|
|
1593 check_asm (t);
|
|
|
1594 break;
|
|
|
1595
|
|
|
1596 default:
|
|
|
1597 break;
|
|
|
1598 }
|
|
|
1599
|
|
|
1600 return;
|
|
|
1601 }
|
|
|
1602
|
|
|
1603
|
|
|
1604 /* The init routine for analyzing global static variable usage. See
|
|
|
1605 comments at top for description. */
|
|
|
1606 static void
|
|
|
1607 ipa_init (void)
|
|
|
1608 {
|
|
|
1609 bitmap_obstack_initialize (&ipa_obstack);
|
|
|
1610 global_types_exposed_parameter = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1611 global_types_full_escape = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1612 global_types_seen = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1613
|
|
|
1614 uid_to_canon_type = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
|
|
1615 all_canon_types = splay_tree_new (compare_type_brand, 0, 0);
|
|
|
1616 type_to_canon_type = splay_tree_new (splay_tree_compare_pointers, 0, 0);
|
|
|
1617 uid_to_subtype_map = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
|
|
1618 uid_to_addressof_down_map = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
|
|
1619 uid_to_addressof_up_map = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
|
|
1620
|
|
|
1621 /* There are some shared nodes, in particular the initializers on
|
|
|
1622 static declarations. We do not need to scan them more than once
|
|
|
1623 since all we would be interested in are the addressof
|
|
|
1624 operations. */
|
|
|
1625 visited_nodes = pointer_set_create ();
|
|
|
1626 initialized = true;
|
|
|
1627 }
|
|
|
1628
|
|
|
1629 /* Check out the rhs of a static or global initialization VNODE to see
|
|
|
1630 if any of them contain addressof operations. Note that some of
|
|
|
1631 these variables may not even be referenced in the code in this
|
|
|
1632 compilation unit but their right hand sides may contain references
|
|
|
1633 to variables defined within this unit. */
|
|
|
1634
|
|
|
1635 static void
|
|
|
1636 analyze_variable (struct varpool_node *vnode)
|
|
|
1637 {
|
|
|
1638 tree global = vnode->decl;
|
|
|
1639 tree type = get_canon_type (TREE_TYPE (global), false, false);
|
|
|
1640
|
|
|
1641 /* If this variable has exposure beyond the compilation unit, add
|
|
|
1642 its type to the global types. */
|
|
|
1643
|
|
|
1644 if (vnode->externally_visible)
|
|
|
1645 mark_interesting_type (type, FULL_ESCAPE);
|
|
|
1646
|
|
|
1647 gcc_assert (TREE_CODE (global) == VAR_DECL);
|
|
|
1648
|
|
|
1649 if (DECL_INITIAL (global))
|
|
|
1650 check_tree (DECL_INITIAL (global));
|
|
|
1651 }
|
|
|
1652
|
|
|
1653 /* This is the main routine for finding the reference patterns for
|
|
|
1654 global variables within a function FN. */
|
|
|
1655
|
|
|
1656 static void
|
|
|
1657 analyze_function (struct cgraph_node *fn)
|
|
|
1658 {
|
|
|
1659 tree decl = fn->decl;
|
|
|
1660 check_function_parameter_and_return_types (decl,
|
|
|
1661 fn->local.externally_visible);
|
|
|
1662 if (dump_file)
|
|
|
1663 fprintf (dump_file, "\n local analysis of %s", cgraph_node_name (fn));
|
|
|
1664
|
|
|
1665 {
|
|
|
1666 struct function *this_cfun = DECL_STRUCT_FUNCTION (decl);
|
|
|
1667 basic_block this_block;
|
|
|
1668
|
|
|
1669 FOR_EACH_BB_FN (this_block, this_cfun)
|
|
|
1670 {
|
|
|
1671 gimple_stmt_iterator gsi;
|
|
|
1672 for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi))
|
|
|
1673 scan_for_refs (gsi_stmt (gsi));
|
|
|
1674 }
|
|
|
1675 }
|
|
|
1676
|
|
|
1677 /* There may be const decls with interesting right hand sides. */
|
|
|
1678 if (DECL_STRUCT_FUNCTION (decl))
|
|
|
1679 {
|
|
|
1680 tree step;
|
|
|
1681 for (step = DECL_STRUCT_FUNCTION (decl)->local_decls;
|
|
|
1682 step;
|
|
|
1683 step = TREE_CHAIN (step))
|
|
|
1684 {
|
|
|
1685 tree var = TREE_VALUE (step);
|
|
|
1686 if (TREE_CODE (var) == VAR_DECL
|
|
|
1687 && DECL_INITIAL (var)
|
|
|
1688 && !TREE_STATIC (var))
|
|
|
1689 check_tree (DECL_INITIAL (var));
|
|
|
1690 get_canon_type (TREE_TYPE (var), false, false);
|
|
|
1691 }
|
|
|
1692 }
|
|
|
1693 }
|
|
|
1694
|
|
|
1695
|
|
|
1696
|
|
|
1697 /* Convert a type_UID into a type. */
|
|
|
1698 static tree
|
|
|
1699 type_for_uid (int uid)
|
|
|
1700 {
|
|
|
1701 splay_tree_node result =
|
|
|
1702 splay_tree_lookup (uid_to_canon_type, (splay_tree_key) uid);
|
|
|
1703
|
|
|
1704 if (result)
|
|
|
1705 return (tree) result->value;
|
|
|
1706 else return NULL;
|
|
|
1707 }
|
|
|
1708
|
|
|
1709 /* Return a bitmap with the subtypes of the type for UID. If it
|
|
|
1710 does not exist, return either NULL or a new bitmap depending on the
|
|
|
1711 value of CREATE. */
|
|
|
1712
|
|
|
1713 static bitmap
|
|
|
1714 subtype_map_for_uid (int uid, bool create)
|
|
|
1715 {
|
|
|
1716 splay_tree_node result = splay_tree_lookup (uid_to_subtype_map,
|
|
|
1717 (splay_tree_key) uid);
|
|
|
1718
|
|
|
1719 if (result)
|
|
|
1720 return (bitmap) result->value;
|
|
|
1721 else if (create)
|
|
|
1722 {
|
|
|
1723 bitmap subtype_map = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1724 splay_tree_insert (uid_to_subtype_map,
|
|
|
1725 uid,
|
|
|
1726 (splay_tree_value)subtype_map);
|
|
|
1727 return subtype_map;
|
|
|
1728 }
|
|
|
1729 else return NULL;
|
|
|
1730 }
|
|
|
1731
|
|
|
1732 /* Mark all of the supertypes and field types of TYPE as being seen.
|
|
|
1733 Also accumulate the subtypes for each type so that
|
|
|
1734 close_types_full_escape can mark a subtype as escaping if the
|
|
|
1735 supertype escapes. */
|
|
|
1736
|
|
|
1737 static void
|
|
|
1738 close_type_seen (tree type)
|
|
|
1739 {
|
|
|
1740 tree field;
|
|
|
1741 int i, uid;
|
|
|
1742 tree binfo, base_binfo;
|
|
|
1743
|
|
|
1744 /* See thru all pointer tos and array ofs. */
|
|
|
1745 type = get_canon_type (type, true, true);
|
|
|
1746 if (!type)
|
|
|
1747 return;
|
|
|
1748
|
|
|
1749 uid = TYPE_UID (type);
|
|
|
1750
|
|
|
1751 if (bitmap_bit_p (been_there_done_that, uid))
|
|
|
1752 return;
|
|
|
1753 bitmap_set_bit (been_there_done_that, uid);
|
|
|
1754
|
|
|
1755 /* If we are doing a language with a type hierarchy, mark all of
|
|
|
1756 the superclasses. */
|
|
|
1757 if (TYPE_BINFO (type))
|
|
|
1758 for (binfo = TYPE_BINFO (type), i = 0;
|
|
|
1759 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
|
|
|
1760 {
|
|
|
1761 tree binfo_type = BINFO_TYPE (base_binfo);
|
|
|
1762 bitmap subtype_map = subtype_map_for_uid
|
|
|
1763 (TYPE_UID (TYPE_MAIN_VARIANT (binfo_type)), true);
|
|
|
1764 bitmap_set_bit (subtype_map, uid);
|
|
|
1765 close_type_seen (get_canon_type (binfo_type, true, true));
|
|
|
1766 }
|
|
|
1767
|
|
|
1768 /* If the field is a struct or union type, mark all of the
|
|
|
1769 subfields. */
|
|
|
1770 for (field = TYPE_FIELDS (type);
|
|
|
1771 field;
|
|
|
1772 field = TREE_CHAIN (field))
|
|
|
1773 {
|
|
|
1774 tree field_type;
|
|
|
1775 if (TREE_CODE (field) != FIELD_DECL)
|
|
|
1776 continue;
|
|
|
1777
|
|
|
1778 field_type = TREE_TYPE (field);
|
|
|
1779 if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0)
|
|
|
1780 close_type_seen (get_canon_type (field_type, true, true));
|
|
|
1781 }
|
|
|
1782 }
|
|
|
1783
|
|
|
1784 /* Take a TYPE that has been passed by value to an external function
|
|
|
1785 and mark all of the fields that have pointer types as escaping. For
|
|
|
1786 any of the non pointer types that are structures or unions,
|
|
|
1787 recurse. TYPE is never a pointer type. */
|
|
|
1788
|
|
|
1789 static void
|
|
|
1790 close_type_exposed_parameter (tree type)
|
|
|
1791 {
|
|
|
1792 tree field;
|
|
|
1793 int uid;
|
|
|
1794
|
|
|
1795 type = get_canon_type (type, false, false);
|
|
|
1796 if (!type)
|
|
|
1797 return;
|
|
|
1798 uid = TYPE_UID (type);
|
|
|
1799 gcc_assert (!POINTER_TYPE_P (type));
|
|
|
1800
|
|
|
1801 if (bitmap_bit_p (been_there_done_that, uid))
|
|
|
1802 return;
|
|
|
1803 bitmap_set_bit (been_there_done_that, uid);
|
|
|
1804
|
|
|
1805 /* If the field is a struct or union type, mark all of the
|
|
|
1806 subfields. */
|
|
|
1807 for (field = TYPE_FIELDS (type);
|
|
|
1808 field;
|
|
|
1809 field = TREE_CHAIN (field))
|
|
|
1810 {
|
|
|
1811 tree field_type;
|
|
|
1812
|
|
|
1813 if (TREE_CODE (field) != FIELD_DECL)
|
|
|
1814 continue;
|
|
|
1815
|
|
|
1816 field_type = get_canon_type (TREE_TYPE (field), false, false);
|
|
|
1817 mark_interesting_type (field_type, EXPOSED_PARAMETER);
|
|
|
1818
|
|
|
1819 /* Only recurse for non pointer types of structures and unions. */
|
|
|
1820 if (ipa_type_escape_star_count_of_interesting_type (field_type) == 0)
|
|
|
1821 close_type_exposed_parameter (field_type);
|
|
|
1822 }
|
|
|
1823 }
|
|
|
1824
|
|
|
1825 /* The next function handles the case where a type fully escapes.
|
|
|
1826 This means that not only does the type itself escape,
|
|
|
1827
|
|
|
1828 a) the type of every field recursively escapes
|
|
|
1829 b) the type of every subtype escapes as well as the super as well
|
|
|
1830 as all of the pointer to types for each field.
|
|
|
1831
|
|
|
1832 Note that pointer to types are not marked as escaping. If the
|
|
|
1833 pointed to type escapes, the pointer to type also escapes.
|
|
|
1834
|
|
|
1835 Take a TYPE that has had the address taken for an instance of it
|
|
|
1836 and mark all of the types for its fields as having their addresses
|
|
|
1837 taken. */
|
|
|
1838
|
|
|
1839 static void
|
|
|
1840 close_type_full_escape (tree type)
|
|
|
1841 {
|
|
|
1842 tree field;
|
|
|
1843 unsigned int i;
|
|
|
1844 int uid;
|
|
|
1845 tree binfo, base_binfo;
|
|
|
1846 bitmap_iterator bi;
|
|
|
1847 bitmap subtype_map;
|
|
|
1848 splay_tree_node address_result;
|
|
|
1849
|
|
|
1850 /* Strip off any pointer or array types. */
|
|
|
1851 type = get_canon_type (type, true, true);
|
|
|
1852 if (!type)
|
|
|
1853 return;
|
|
|
1854 uid = TYPE_UID (type);
|
|
|
1855
|
|
|
1856 if (bitmap_bit_p (been_there_done_that, uid))
|
|
|
1857 return;
|
|
|
1858 bitmap_set_bit (been_there_done_that, uid);
|
|
|
1859
|
|
|
1860 subtype_map = subtype_map_for_uid (uid, false);
|
|
|
1861
|
|
|
1862 /* If we are doing a language with a type hierarchy, mark all of
|
|
|
1863 the superclasses. */
|
|
|
1864 if (TYPE_BINFO (type))
|
|
|
1865 for (binfo = TYPE_BINFO (type), i = 0;
|
|
|
1866 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
|
|
|
1867 {
|
|
|
1868 tree binfotype = BINFO_TYPE (base_binfo);
|
|
|
1869 binfotype = mark_type (binfotype, FULL_ESCAPE);
|
|
|
1870 close_type_full_escape (binfotype);
|
|
|
1871 }
|
|
|
1872
|
|
|
1873 /* Mark as escaped any types that have been down casted to
|
|
|
1874 this type. */
|
|
|
1875 if (subtype_map)
|
|
|
1876 EXECUTE_IF_SET_IN_BITMAP (subtype_map, 0, i, bi)
|
|
|
1877 {
|
|
|
1878 tree subtype = type_for_uid (i);
|
|
|
1879 subtype = mark_type (subtype, FULL_ESCAPE);
|
|
|
1880 close_type_full_escape (subtype);
|
|
|
1881 }
|
|
|
1882
|
|
|
1883 /* If the field is a struct or union type, mark all of the
|
|
|
1884 subfields. */
|
|
|
1885 for (field = TYPE_FIELDS (type);
|
|
|
1886 field;
|
|
|
1887 field = TREE_CHAIN (field))
|
|
|
1888 {
|
|
|
1889 tree field_type;
|
|
|
1890 if (TREE_CODE (field) != FIELD_DECL)
|
|
|
1891 continue;
|
|
|
1892
|
|
|
1893 field_type = TREE_TYPE (field);
|
|
|
1894 if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0)
|
|
|
1895 {
|
|
|
1896 field_type = mark_type (field_type, FULL_ESCAPE);
|
|
|
1897 close_type_full_escape (field_type);
|
|
|
1898 }
|
|
|
1899 }
|
|
|
1900
|
|
|
1901 /* For all of the types A that contain this type B and were part of
|
|
|
1902 an expression like "&...A.B...", mark the A's as escaping. */
|
|
|
1903 address_result = splay_tree_lookup (uid_to_addressof_up_map,
|
|
|
1904 (splay_tree_key) uid);
|
|
|
1905 if (address_result)
|
|
|
1906 {
|
|
|
1907 bitmap containing_classes = (bitmap) address_result->value;
|
|
|
1908 EXECUTE_IF_SET_IN_BITMAP (containing_classes, 0, i, bi)
|
|
|
1909 {
|
|
|
1910 close_type_full_escape (type_for_uid (i));
|
|
|
1911 }
|
|
|
1912 }
|
|
|
1913 }
|
|
|
1914
|
|
|
1915 /* Transitively close the addressof bitmap for the type with UID.
|
|
|
1916 This means that if we had a.b and b.c, a would have both b and c in
|
|
|
1917 its maps. */
|
|
|
1918
|
|
|
1919 static bitmap
|
|
|
1920 close_addressof_down (int uid)
|
|
|
1921 {
|
|
|
1922 bitmap_iterator bi;
|
|
|
1923 splay_tree_node result =
|
|
|
1924 splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid);
|
|
|
1925 bitmap map = NULL;
|
|
|
1926 bitmap new_map;
|
|
|
1927 unsigned int i;
|
|
|
1928
|
|
|
1929 if (result)
|
|
|
1930 map = (bitmap) result->value;
|
|
|
1931 else
|
|
|
1932 return NULL;
|
|
|
1933
|
|
|
1934 if (bitmap_bit_p (been_there_done_that, uid))
|
|
|
1935 return map;
|
|
|
1936 bitmap_set_bit (been_there_done_that, uid);
|
|
|
1937
|
|
|
1938 /* If the type escapes, get rid of the addressof map, it will not be
|
|
|
1939 needed. */
|
|
|
1940 if (bitmap_bit_p (global_types_full_escape, uid))
|
|
|
1941 {
|
|
|
1942 BITMAP_FREE (map);
|
|
|
1943 splay_tree_remove (uid_to_addressof_down_map, (splay_tree_key) uid);
|
|
|
1944 return NULL;
|
|
|
1945 }
|
|
|
1946
|
|
|
1947 /* The new_map will have all of the bits for the enclosed fields and
|
|
|
1948 will have the unique id version of the old map. */
|
|
|
1949 new_map = BITMAP_ALLOC (&ipa_obstack);
|
|
|
1950
|
|
|
1951 EXECUTE_IF_SET_IN_BITMAP (map, 0, i, bi)
|
|
|
1952 {
|
|
|
1953 bitmap submap = close_addressof_down (i);
|
|
|
1954 bitmap_set_bit (new_map, i);
|
|
|
1955 if (submap)
|
|
|
1956 bitmap_ior_into (new_map, submap);
|
|
|
1957 }
|
|
|
1958 result->value = (splay_tree_value) new_map;
|
|
|
1959
|
|
|
1960 BITMAP_FREE (map);
|
|
|
1961 return new_map;
|
|
|
1962 }
|
|
|
1963
|
|
|
1964
|
|
|
1965 /* The main entry point for type escape analysis. */
|
|
|
1966
|
|
|
1967 static unsigned int
|
|
|
1968 type_escape_execute (void)
|
|
|
1969 {
|
|
|
1970 struct cgraph_node *node;
|
|
|
1971 struct varpool_node *vnode;
|
|
|
1972 unsigned int i;
|
|
|
1973 bitmap_iterator bi;
|
|
|
1974 splay_tree_node result;
|
|
|
1975
|
|
|
1976 ipa_init ();
|
|
|
1977
|
|
|
1978 /* Process all of the variables first. */
|
|
|
1979 FOR_EACH_STATIC_VARIABLE (vnode)
|
|
|
1980 analyze_variable (vnode);
|
|
|
1981
|
|
|
1982 /* Process all of the functions next.
|
|
|
1983
|
|
|
1984 We do not want to process any of the clones so we check that this
|
|
|
1985 is a master clone. However, we do need to process any
|
|
|
1986 AVAIL_OVERWRITABLE functions (these are never clones) because
|
|
|
1987 they may cause a type variable to escape.
|
|
|
1988 */
|
|
|
1989 for (node = cgraph_nodes; node; node = node->next)
|
|
|
1990 if (node->analyzed
|
|
|
1991 && (cgraph_is_master_clone (node)
|
|
|
1992 || (cgraph_function_body_availability (node) == AVAIL_OVERWRITABLE)))
|
|
|
1993 analyze_function (node);
|
|
|
1994
|
|
|
1995
|
|
|
1996 pointer_set_destroy (visited_nodes);
|
|
|
1997 visited_nodes = NULL;
|
|
|
1998
|
|
|
1999 /* Do all of the closures to discover which types escape the
|
|
|
2000 compilation unit. */
|
|
|
2001
|
|
|
2002 been_there_done_that = BITMAP_ALLOC (&ipa_obstack);
|
|
|
2003 bitmap_tmp = BITMAP_ALLOC (&ipa_obstack);
|
|
|
2004
|
|
|
2005 /* Examine the types that we have directly seen in scanning the code
|
|
|
2006 and add to that any contained types or superclasses. */
|
|
|
2007
|
|
|
2008 bitmap_copy (bitmap_tmp, global_types_seen);
|
|
|
2009 EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi)
|
|
|
2010 {
|
|
|
2011 tree type = type_for_uid (i);
|
|
|
2012 /* Only look at records and unions and pointer tos. */
|
|
|
2013 if (ipa_type_escape_star_count_of_interesting_or_array_type (type) >= 0)
|
|
|
2014 close_type_seen (type);
|
|
|
2015 }
|
|
|
2016 bitmap_clear (been_there_done_that);
|
|
|
2017
|
|
|
2018 /* Examine all of the types passed by value and mark any enclosed
|
|
|
2019 pointer types as escaping. */
|
|
|
2020 bitmap_copy (bitmap_tmp, global_types_exposed_parameter);
|
|
|
2021 EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi)
|
|
|
2022 {
|
|
|
2023 close_type_exposed_parameter (type_for_uid (i));
|
|
|
2024 }
|
|
|
2025 bitmap_clear (been_there_done_that);
|
|
|
2026
|
|
|
2027 /* Close the types for escape. If something escapes, then any
|
|
|
2028 enclosed types escape as well as any subtypes. */
|
|
|
2029 bitmap_copy (bitmap_tmp, global_types_full_escape);
|
|
|
2030 EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi)
|
|
|
2031 {
|
|
|
2032 close_type_full_escape (type_for_uid (i));
|
|
|
2033 }
|
|
|
2034 bitmap_clear (been_there_done_that);
|
|
|
2035
|
|
|
2036 /* Before this pass, the uid_to_addressof_down_map for type X
|
|
|
2037 contained an entry for Y if there had been an operation of the
|
|
|
2038 form &X.Y. This step adds all of the fields contained within Y
|
|
|
2039 (recursively) to X's map. */
|
|
|
2040
|
|
|
2041 result = splay_tree_min (uid_to_addressof_down_map);
|
|
|
2042 while (result)
|
|
|
2043 {
|
|
|
2044 int uid = result->key;
|
|
|
2045 /* Close the addressof map, i.e. copy all of the transitive
|
|
|
2046 substructures up to this level. */
|
|
|
2047 close_addressof_down (uid);
|
|
|
2048 result = splay_tree_successor (uid_to_addressof_down_map, uid);
|
|
|
2049 }
|
|
|
2050
|
|
|
2051 /* Do not need the array types and pointer types in the persistent
|
|
|
2052 data structures. */
|
|
|
2053 result = splay_tree_min (all_canon_types);
|
|
|
2054 while (result)
|
|
|
2055 {
|
|
|
2056 tree type = (tree) result->value;
|
|
|
2057 tree key = (tree) result->key;
|
|
|
2058 if (POINTER_TYPE_P (type)
|
|
|
2059 || TREE_CODE (type) == ARRAY_TYPE)
|
|
|
2060 {
|
|
|
2061 splay_tree_remove (all_canon_types, (splay_tree_key) result->key);
|
|
|
2062 splay_tree_remove (type_to_canon_type, (splay_tree_key) type);
|
|
|
2063 splay_tree_remove (uid_to_canon_type, (splay_tree_key) TYPE_UID (type));
|
|
|
2064 bitmap_clear_bit (global_types_seen, TYPE_UID (type));
|
|
|
2065 }
|
|
|
2066 result = splay_tree_successor (all_canon_types, (splay_tree_key) key);
|
|
|
2067 }
|
|
|
2068
|
|
|
2069 if (dump_file)
|
|
|
2070 {
|
|
|
2071 EXECUTE_IF_SET_IN_BITMAP (global_types_seen, 0, i, bi)
|
|
|
2072 {
|
|
|
2073 /* The pointer types are in the global_types_full_escape
|
|
|
2074 bitmap but not in the backwards map. They also contain
|
|
|
2075 no useful information since they are not marked. */
|
|
|
2076 tree type = type_for_uid (i);
|
|
|
2077 fprintf(dump_file, "type %d ", i);
|
|
|
2078 print_generic_expr (dump_file, type, 0);
|
|
|
2079 if (bitmap_bit_p (global_types_full_escape, i))
|
|
|
2080 fprintf(dump_file, " escaped\n");
|
|
|
2081 else
|
|
|
2082 fprintf(dump_file, " contained\n");
|
|
|
2083 }
|
|
|
2084 }
|
|
|
2085
|
|
|
2086 /* Get rid of uid_to_addressof_up_map and its bitmaps. */
|
|
|
2087 result = splay_tree_min (uid_to_addressof_up_map);
|
|
|
2088 while (result)
|
|
|
2089 {
|
|
|
2090 int uid = (int)result->key;
|
|
|
2091 bitmap bm = (bitmap)result->value;
|
|
|
2092
|
|
|
2093 BITMAP_FREE (bm);
|
|
|
2094 splay_tree_remove (uid_to_addressof_up_map, (splay_tree_key) uid);
|
|
|
2095 result = splay_tree_successor (uid_to_addressof_up_map, uid);
|
|
|
2096 }
|
|
|
2097
|
|
|
2098 /* Get rid of the subtype map. */
|
|
|
2099 result = splay_tree_min (uid_to_subtype_map);
|
|
|
2100 while (result)
|
|
|
2101 {
|
|
|
2102 bitmap b = (bitmap)result->value;
|
|
|
2103 BITMAP_FREE(b);
|
|
|
2104 splay_tree_remove (uid_to_subtype_map, result->key);
|
|
|
2105 result = splay_tree_min (uid_to_subtype_map);
|
|
|
2106 }
|
|
|
2107 splay_tree_delete (uid_to_subtype_map);
|
|
|
2108 uid_to_subtype_map = NULL;
|
|
|
2109
|
|
|
2110 BITMAP_FREE (global_types_exposed_parameter);
|
|
|
2111 BITMAP_FREE (been_there_done_that);
|
|
|
2112 BITMAP_FREE (bitmap_tmp);
|
|
|
2113 return 0;
|
|
|
2114 }
|
|
|
2115
|
|
|
2116 static bool
|
|
|
2117 gate_type_escape_vars (void)
|
|
|
2118 {
|
|
|
2119 return (flag_ipa_type_escape
|
|
|
2120 /* Don't bother doing anything if the program has errors. */
|
|
|
2121 && !(errorcount || sorrycount));
|
|
|
2122 }
|
|
|
2123
|
|
|
2124 struct simple_ipa_opt_pass pass_ipa_type_escape =
|
|
|
2125 {
|
|
|
2126 {
|
|
|
2127 SIMPLE_IPA_PASS,
|
|
|
2128 "type-escape-var", /* name */
|
|
|
2129 gate_type_escape_vars, /* gate */
|
|
|
2130 type_escape_execute, /* execute */
|
|
|
2131 NULL, /* sub */
|
|
|
2132 NULL, /* next */
|
|
|
2133 0, /* static_pass_number */
|
|
|
2134 TV_IPA_TYPE_ESCAPE, /* tv_id */
|
|
|
2135 0, /* properties_required */
|
|
|
2136 0, /* properties_provided */
|
|
|
2137 0, /* properties_destroyed */
|
|
|
2138 0, /* todo_flags_start */
|
|
|
2139 0 /* todo_flags_finish */
|
|
|
2140 }
|
|
|
2141 };
|
