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0
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1 /* Basic IPA optimizations and utilities.
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2 Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation,
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3 Inc.
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4
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5 This file is part of GCC.
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6
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7 GCC is free software; you can redistribute it and/or modify it under
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8 the terms of the GNU General Public License as published by the Free
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9 Software Foundation; either version 3, or (at your option) any later
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10 version.
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11
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12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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15 for more details.
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16
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17 You should have received a copy of the GNU General Public License
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18 along with GCC; see the file COPYING3. If not see
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19 <http://www.gnu.org/licenses/>. */
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20
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21 #include "config.h"
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22 #include "system.h"
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23 #include "coretypes.h"
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24 #include "tm.h"
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25 #include "cgraph.h"
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26 #include "tree-pass.h"
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27 #include "timevar.h"
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28
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29 /* Fill array order with all nodes with output flag set in the reverse
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30 topological order. */
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31
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32 int
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33 cgraph_postorder (struct cgraph_node **order)
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34 {
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35 struct cgraph_node *node, *node2;
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36 int stack_size = 0;
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37 int order_pos = 0;
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38 struct cgraph_edge *edge, last;
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39
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40 struct cgraph_node **stack =
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41 XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
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42
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43 /* We have to deal with cycles nicely, so use a depth first traversal
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44 output algorithm. Ignore the fact that some functions won't need
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45 to be output and put them into order as well, so we get dependencies
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46 right through inline functions. */
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47 for (node = cgraph_nodes; node; node = node->next)
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48 node->aux = NULL;
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49 for (node = cgraph_nodes; node; node = node->next)
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50 if (!node->aux)
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51 {
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52 node2 = node;
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53 if (!node->callers)
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54 node->aux = &last;
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55 else
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56 node->aux = node->callers;
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57 while (node2)
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58 {
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59 while (node2->aux != &last)
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60 {
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61 edge = (struct cgraph_edge *) node2->aux;
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62 if (edge->next_caller)
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63 node2->aux = edge->next_caller;
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64 else
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65 node2->aux = &last;
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66 if (!edge->caller->aux)
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67 {
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68 if (!edge->caller->callers)
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69 edge->caller->aux = &last;
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70 else
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71 edge->caller->aux = edge->caller->callers;
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72 stack[stack_size++] = node2;
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73 node2 = edge->caller;
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74 break;
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75 }
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76 }
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77 if (node2->aux == &last)
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78 {
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79 order[order_pos++] = node2;
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80 if (stack_size)
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81 node2 = stack[--stack_size];
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82 else
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83 node2 = NULL;
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84 }
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85 }
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86 }
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87 free (stack);
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88 for (node = cgraph_nodes; node; node = node->next)
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89 node->aux = NULL;
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90 return order_pos;
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91 }
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92
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93 /* Perform reachability analysis and reclaim all unreachable nodes.
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94 If BEFORE_INLINING_P is true this function is called before inlining
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95 decisions has been made. If BEFORE_INLINING_P is false this function also
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96 removes unneeded bodies of extern inline functions. */
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97
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98 bool
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99 cgraph_remove_unreachable_nodes (bool before_inlining_p, FILE *file)
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100 {
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101 struct cgraph_node *first = (struct cgraph_node *) (void *) 1;
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102 struct cgraph_node *node, *next;
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103 bool changed = false;
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104
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105 #ifdef ENABLE_CHECKING
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106 verify_cgraph ();
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107 #endif
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108 if (file)
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109 fprintf (file, "\nReclaiming functions:");
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110 #ifdef ENABLE_CHECKING
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111 for (node = cgraph_nodes; node; node = node->next)
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112 gcc_assert (!node->aux);
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113 #endif
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114 for (node = cgraph_nodes; node; node = node->next)
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115 if (node->needed && !node->global.inlined_to
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116 && ((!DECL_EXTERNAL (node->decl))
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117 || !node->analyzed
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118 || before_inlining_p))
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119 {
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120 node->aux = first;
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121 first = node;
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122 }
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123 else
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124 gcc_assert (!node->aux);
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125
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126 /* Perform reachability analysis. As a special case do not consider
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127 extern inline functions not inlined as live because we won't output
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128 them at all. */
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129 while (first != (void *) 1)
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130 {
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131 struct cgraph_edge *e;
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132 node = first;
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133 first = (struct cgraph_node *) first->aux;
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134
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135 for (e = node->callees; e; e = e->next_callee)
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136 if (!e->callee->aux
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137 && node->analyzed
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138 && (!e->inline_failed || !e->callee->analyzed
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139 || (!DECL_EXTERNAL (e->callee->decl))
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140 || before_inlining_p))
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141 {
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142 e->callee->aux = first;
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143 first = e->callee;
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144 }
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145 }
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146
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147 /* Remove unreachable nodes. Extern inline functions need special care;
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148 Unreachable extern inline functions shall be removed.
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149 Reachable extern inline functions we never inlined shall get their bodies
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150 eliminated.
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151 Reachable extern inline functions we sometimes inlined will be turned into
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152 unanalyzed nodes so they look like for true extern functions to the rest
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153 of code. Body of such functions is released via remove_node once the
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154 inline clones are eliminated. */
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155 for (node = cgraph_nodes; node; node = next)
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156 {
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157 next = node->next;
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158 if (!node->aux)
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159 {
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160 node->global.inlined_to = NULL;
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161 if (file)
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162 fprintf (file, " %s", cgraph_node_name (node));
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163 if (!node->analyzed || !DECL_EXTERNAL (node->decl)
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164 || before_inlining_p)
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165 cgraph_remove_node (node);
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166 else
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167 {
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168 struct cgraph_edge *e;
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169
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170 for (e = node->callers; e; e = e->next_caller)
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171 if (e->caller->aux)
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172 break;
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173 if (e || node->needed)
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174 {
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175 struct cgraph_node *clone;
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176
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177 for (clone = node->next_clone; clone;
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178 clone = clone->next_clone)
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179 if (clone->aux)
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180 break;
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181 if (!clone)
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182 {
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183 cgraph_release_function_body (node);
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184 node->analyzed = false;
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185 }
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186 cgraph_node_remove_callees (node);
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187 node->analyzed = false;
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188 node->local.inlinable = false;
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189 }
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190 else
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191 cgraph_remove_node (node);
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192 }
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193 changed = true;
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194 }
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195 }
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196 for (node = cgraph_nodes; node; node = node->next)
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197 node->aux = NULL;
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198 #ifdef ENABLE_CHECKING
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199 verify_cgraph ();
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200 #endif
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201 return changed;
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202 }
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203
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204 /* Mark visibility of all functions.
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205
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206 A local function is one whose calls can occur only in the current
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207 compilation unit and all its calls are explicit, so we can change
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208 its calling convention. We simply mark all static functions whose
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209 address is not taken as local.
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210
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211 We also change the TREE_PUBLIC flag of all declarations that are public
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212 in language point of view but we want to overwrite this default
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213 via visibilities for the backend point of view. */
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214
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215 static unsigned int
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216 function_and_variable_visibility (void)
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217 {
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218 struct cgraph_node *node;
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219 struct varpool_node *vnode;
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220
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221 for (node = cgraph_nodes; node; node = node->next)
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222 {
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223 if (node->reachable
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224 && (DECL_COMDAT (node->decl)
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225 || (!flag_whole_program
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226 && TREE_PUBLIC (node->decl) && !DECL_EXTERNAL (node->decl))))
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227 node->local.externally_visible = true;
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228 if (!node->local.externally_visible && node->analyzed
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229 && !DECL_EXTERNAL (node->decl))
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230 {
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231 gcc_assert (flag_whole_program || !TREE_PUBLIC (node->decl));
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232 TREE_PUBLIC (node->decl) = 0;
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233 }
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234 node->local.local = (!node->needed
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235 && node->analyzed
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236 && !DECL_EXTERNAL (node->decl)
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237 && !node->local.externally_visible);
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238 }
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239 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
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240 {
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241 if (vnode->needed
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242 && !flag_whole_program
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243 && (DECL_COMDAT (vnode->decl) || TREE_PUBLIC (vnode->decl)))
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244 vnode->externally_visible = 1;
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245 if (!vnode->externally_visible)
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246 {
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247 gcc_assert (flag_whole_program || !TREE_PUBLIC (vnode->decl));
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248 TREE_PUBLIC (vnode->decl) = 0;
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249 }
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250 gcc_assert (TREE_STATIC (vnode->decl));
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251 }
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252
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253 if (dump_file)
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254 {
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255 fprintf (dump_file, "\nMarking local functions:");
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256 for (node = cgraph_nodes; node; node = node->next)
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257 if (node->local.local)
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258 fprintf (dump_file, " %s", cgraph_node_name (node));
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259 fprintf (dump_file, "\n\n");
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260 fprintf (dump_file, "\nMarking externally visible functions:");
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261 for (node = cgraph_nodes; node; node = node->next)
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262 if (node->local.externally_visible)
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263 fprintf (dump_file, " %s", cgraph_node_name (node));
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264 fprintf (dump_file, "\n\n");
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265 }
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266 cgraph_function_flags_ready = true;
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267 return 0;
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268 }
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269
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270 struct simple_ipa_opt_pass pass_ipa_function_and_variable_visibility =
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271 {
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272 {
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273 SIMPLE_IPA_PASS,
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274 "visibility", /* name */
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275 NULL, /* gate */
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276 function_and_variable_visibility, /* execute */
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277 NULL, /* sub */
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278 NULL, /* next */
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279 0, /* static_pass_number */
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280 TV_CGRAPHOPT, /* tv_id */
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281 0, /* properties_required */
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282 0, /* properties_provided */
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283 0, /* properties_destroyed */
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284 0, /* todo_flags_start */
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285 TODO_remove_functions | TODO_dump_cgraph/* todo_flags_finish */
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286 }
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287 };
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