1 | /* Translation rules for exception handling code, from Cforall to C. |
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2 | * |
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3 | * Note that these are not final. Names, syntax and the exact translation |
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4 | * will be updated. The first section is the shared definitions, not generated |
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5 | * by the local translations but used by the translated code. |
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6 | * |
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7 | * Most of these exist only after translation (in C code). The first (the |
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8 | * exception type) has to exist in Cforall code so that it can be used |
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9 | * directly in Cforall. The two __throw_* functions might have wrappers in |
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10 | * Cforall, but the underlying functions should probably be C. struct |
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11 | * stack_exception_data has to exist inside of the coroutine data structures |
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12 | * and so should be compiled as they are. |
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13 | */ |
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14 | |
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15 | // Currently it is a typedef for int, but later it will be a new type. |
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16 | typedef int exception; |
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17 | |
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18 | void __throw_terminate(exception except) __attribute__((noreturn)); |
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19 | void __rethrow_terminate() __attribute__((noreturn)); |
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20 | void __throw_resume(exception except); |
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21 | |
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22 | void __try_terminate(void (*try_block)(), |
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23 | void (*catch_block)(int index, exception except), |
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24 | int (*match_block)(exception except)); |
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25 | |
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26 | struct __try_resume_node { |
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27 | struct __try_resume_node * next; |
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28 | bool (*try_to_handle)(exception except); |
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29 | }; |
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30 | |
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31 | void __try_resume_cleanup(struct __try_resume_node * node); |
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32 | |
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33 | struct __cleanup_hook {}; |
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34 | |
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35 | // An instance of the following must be paired with every stack. |
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36 | struct stack_exception_data { |
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37 | __try_resume_node * top_resume_data; |
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38 | // Other pointers may be required for re-resume. |
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39 | |
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40 | exception current_exception; |
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41 | int handler_index; |
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42 | }; |
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43 | |
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44 | |
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45 | // Translations: |
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46 | |
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47 | // Throws: |
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48 | "Cforall" |
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49 | |
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50 | throw exception_instance; |
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51 | |
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52 | resume exception_instance; |
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53 | |
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54 | "C" |
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55 | |
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56 | __throw_terminate(exception_instance); |
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57 | |
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58 | __throw_resume(exception_instance); |
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59 | |
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60 | |
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61 | |
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62 | // Rethrows (inside matching handlers): |
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63 | "Cforall" |
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64 | |
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65 | throw; |
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66 | |
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67 | resume; |
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68 | |
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69 | "C" |
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70 | |
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71 | __rethrow_terminate(); |
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72 | |
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73 | return false; |
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74 | |
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75 | |
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76 | // Termination Handlers: |
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77 | "Cforall" |
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78 | |
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79 | void try_terminate() { |
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80 | try { |
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81 | insideTry(); |
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82 | } |
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83 | catch (SomeException) { |
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84 | fiddleThing(); |
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85 | } |
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86 | catch (OtherException err ; err.priority > 3) { |
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87 | twiddleWidget(); |
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88 | } |
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89 | } |
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90 | |
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91 | "C" |
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92 | |
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93 | void try_terminate() { |
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94 | { |
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95 | void try1() { |
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96 | insideTry(); |
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97 | } |
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98 | // index is not nessasary, but should be much faster than going over |
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99 | // all the checks in if we can find a way to pass it in. |
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100 | void catch1(exception except, int index) { |
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101 | switch (index) { |
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102 | case 1: |
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103 | // if it is referenced in the handler, cast except. |
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104 | { |
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105 | fiddleThing(); |
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106 | } |
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107 | return; |
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108 | case 2: |
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109 | { |
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110 | twiddleWidget(); |
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111 | } |
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112 | return; |
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113 | default: |
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114 | // Error, should never be reached. |
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115 | } |
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116 | } |
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117 | int match1(exception except) { |
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118 | OtherException inner_except; |
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119 | if (dynamic_cast__SomeException(except)) { |
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120 | return 1; |
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121 | } |
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122 | else if ( (inner_except = dynamic_cast__OtherException(except)) && |
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123 | inner_except.priority > 3) { |
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124 | return 2; |
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125 | } |
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126 | else return 0; |
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127 | } |
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128 | __try_terminate(try1, catch1, match1); |
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129 | } |
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130 | } |
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131 | |
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132 | |
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133 | // Resumption Handlers: |
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134 | "Cforall" |
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135 | |
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136 | void try_resume() { |
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137 | try { |
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138 | insideTry(); |
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139 | } |
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140 | catch resume (SomeException) { |
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141 | fiddleThing(); |
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142 | } |
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143 | catch resume (OtherException err ; err.priority > 3) { |
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144 | twiddleWidget(); |
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145 | } |
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146 | } |
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147 | |
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148 | "C" |
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149 | |
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150 | void try_resume() { |
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151 | { |
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152 | bool handle1(exception except) { |
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153 | OtherException inner_except; |
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154 | if (dynamic_cast__SomeException(except)) { |
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155 | fiddleThing(); |
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156 | return true; |
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157 | } else if (dynamic_cast__OtherException(except) && |
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158 | inner_except.priority > 3) { |
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159 | twiddleWidget(); |
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160 | return true; |
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161 | } else { |
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162 | return false; |
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163 | } |
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164 | } |
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165 | struct __try_resume_node data = |
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166 | {.next = stack.except.top_resume, .try_to_handle = handle1}; |
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167 | stack.except.top_resume = &data; |
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168 | |
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169 | struct __cleanup_hook generated_name |
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170 | __attribute__((cleanup(__try_resume_cleanup))); |
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171 | |
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172 | { |
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173 | insideTry(); |
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174 | } |
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175 | } |
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176 | } |
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177 | |
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178 | |
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179 | // Finally Clause: |
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180 | "Cforall" |
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181 | |
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182 | void try_finally() { |
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183 | try { |
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184 | insideTry(); |
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185 | } |
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186 | finally { |
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187 | twiddleWidget(); |
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188 | } |
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189 | } |
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190 | |
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191 | "C" |
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192 | |
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193 | void try_finally() { |
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194 | { |
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195 | void finally1() { |
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196 | twiddleWidget(); |
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197 | } |
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198 | |
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199 | struct __cleanup_hook generated_name |
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200 | __attribute__((cleanup(finally1))); |
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201 | |
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202 | { |
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203 | insideTry(); |
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204 | } |
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205 | } |
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206 | } |
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207 | |
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208 | |
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209 | // Resume + Finally: |
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210 | "Cforall" |
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211 | |
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212 | void try_resume_finally() { |
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213 | try { |
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214 | insideTry(); |
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215 | } |
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216 | catch resume (SomeException) { |
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217 | fiddleThing(); |
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218 | } |
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219 | finally { |
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220 | twiddleWidget(); |
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221 | } |
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222 | } |
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223 | |
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224 | "C" |
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225 | |
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226 | void try_resume_finally() { |
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227 | { |
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228 | void finally1() { |
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229 | twiddleWidget(); |
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230 | } |
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231 | bool handle1(exception except) { |
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232 | if (dynamic_cast__SomeException(except)) { |
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233 | fiddleThing(); |
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234 | return true; |
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235 | } else { |
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236 | return false; |
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237 | } |
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238 | } |
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239 | struct __cleanup_hook generated_name |
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240 | __attribute__((cleanup(finally1))); |
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241 | |
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242 | struct __try_resume_node data = |
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243 | {.next = stack.except.top_resume, .try_to_handle = handle1}; |
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244 | stack.except.top_resume = &data; |
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245 | |
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246 | struct __cleanup_hook generated_name |
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247 | __attribute__((cleanup(__try_resume_cleanup))); |
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248 | } |
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249 | } |
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250 | |
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251 | |
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252 | // Terminate + Resume + Finally: |
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253 | "Cforall" |
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254 | |
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255 | void try_all() { |
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256 | try { |
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257 | insideTry(); |
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258 | } |
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259 | catch (SomeException) { |
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260 | fiddleThing(); |
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261 | } |
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262 | catch resume (OtherException) { |
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263 | twiddleWidget(); |
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264 | } |
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265 | finally { |
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266 | twiddleWidget(); |
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267 | } |
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268 | } |
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269 | |
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270 | "C" |
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271 | |
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272 | void try_all() { |
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273 | { |
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274 | bool handle1() { |
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275 | if (dynamic_cast__OtherException(except)) { |
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276 | twiddleWidget(); |
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277 | return true; |
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278 | } |
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279 | return false; |
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280 | } |
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281 | void try1 () { |
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282 | struct __try_resume_node generated_name = |
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283 | {.next = stack.except.top_resume, .try_to_handle = handle1} |
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284 | __attribute__((cleanup(__try_resume_cleanup))); |
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285 | stack.except.top_resume = &data; |
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286 | |
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287 | insideTry(); |
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288 | } |
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289 | void catch1(exception except, int index) { |
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290 | switch (index) { |
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291 | case 1: |
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292 | fiddleThing(); |
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293 | break; |
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294 | default: |
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295 | // Error if reached. |
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296 | } |
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297 | } |
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298 | int match1(exception except) { |
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299 | if (dynamic_cast__SomeException(except)) { |
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300 | return 1; |
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301 | } |
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302 | return 0; |
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303 | } |
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304 | void finally1() { |
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305 | |
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306 | twiddleWidget(); |
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307 | } |
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308 | struct __cleanup_hook generated_name |
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309 | __attribute__((cleanup(finally1))); |
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310 | |
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311 | __try_terminate(try1, catch1, match1); |
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312 | } |
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313 | } |
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