[465ed18] | 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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[8d50e34] | 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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[465ed18] | 13 | */ |
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| 14 | |
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[8d50e34] | 15 | // Currently it is a typedef for int, but later it will be a new type. |
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[465ed18] | 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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[c529a24] | 19 | void __rethrow_terminate() __attribute__((noreturn)); |
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[465ed18] | 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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[c529a24] | 31 | void __try_resume_cleanup(struct __try_resume_node * node); |
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| 32 | |
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[465ed18] | 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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[35ba584c] | 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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[465ed18] | 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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[c529a24] | 152 | bool handle1(exception except) { |
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[465ed18] | 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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[c529a24] | 166 | {.next = stack.except.top_resume, .try_to_handle = handle1}; |
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[465ed18] | 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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[c529a24] | 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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[465ed18] | 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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[c529a24] | 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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[465ed18] | 281 | void try1 () { |
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[c529a24] | 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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[465ed18] | 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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