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1 /* |
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2 * matiec - a compiler for the programming languages defined in IEC 61131-3 |
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3 * |
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4 * Copyright (C) 2014 Mario de Sousa (msousa@fe.up.pt) |
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5 * |
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6 * This program is free software: you can redistribute it and/or modify |
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7 * it under the terms of the GNU General Public License as published by |
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8 * the Free Software Foundation, either version 3 of the License, or |
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9 * (at your option) any later version. |
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10 * |
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11 * This program is distributed in the hope that it will be useful, |
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 * GNU General Public License for more details. |
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15 * |
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16 * You should have received a copy of the GNU General Public License |
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17 * along with this program. If not, see <http://www.gnu.org/licenses/>. |
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18 * |
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19 * |
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20 * This code is made available on the understanding that it will not be |
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21 * used in safety-critical situations without a full and competent review. |
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22 */ |
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23 |
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24 /* |
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25 * An IEC 61131-3 compiler. |
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26 * |
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27 * Based on the |
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28 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10) |
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29 * |
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30 */ |
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31 |
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32 /* |
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33 * Re-oder the POUs in te library so that no forward references occur. |
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34 * |
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35 * Since stage1_2 now suppport POUs that contain references to POUS that are only declared later, |
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36 * (e.g. a variable of FB1_t is declared, before the FB1_T function block is itself declared!) |
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37 * we may need to re-order all the POUs in the library so that these forward references do not occur. |
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38 * |
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39 * This utility function will do just that. However, it does not destroy the original abstract syntax |
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40 * tree (AST). It instead creates a new re-ordered AST, by instantiating a new library_c object. |
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41 * This new library_c object will however point to the *same* objects of the original AST, just in |
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42 * a new order. |
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43 * This means that the new and original AST share all the object instances, and only use a distinct |
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44 * library_c object! |
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45 */ |
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46 |
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47 #include "remove_forward_dependencies.hh" |
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48 #include "../main.hh" // required for ERROR() and ERROR_MSG() macros. |
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49 #include "../absyntax_utils/absyntax_utils.hh" |
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50 |
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51 |
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52 |
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53 |
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54 |
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55 #define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order) ? (symbol1) : (symbol2)) |
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56 #define LAST_(symbol1, symbol2) (((symbol1)->last_order > (symbol2)->last_order) ? (symbol1) : (symbol2)) |
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57 |
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58 #define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order) ? (symbol1) : (symbol2)) |
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59 #define LAST_(symbol1, symbol2) (((symbol1)->last_order > (symbol2)->last_order) ? (symbol1) : (symbol2)) |
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60 |
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61 #define STAGE3_ERROR(error_level, symbol1, symbol2, ...) { \ |
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62 if (current_display_error_level >= error_level) { \ |
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63 fprintf(stderr, "%s:%d-%d..%d-%d: error: ", \ |
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64 FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\ |
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65 LAST_(symbol1,symbol2) ->last_line, LAST_(symbol1,symbol2) ->last_column);\ |
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66 fprintf(stderr, __VA_ARGS__); \ |
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67 fprintf(stderr, "\n"); \ |
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68 error_count++; \ |
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69 } \ |
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70 } |
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71 |
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72 |
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73 #define STAGE3_WARNING(symbol1, symbol2, ...) { \ |
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74 fprintf(stderr, "%s:%d-%d..%d-%d: warning: ", \ |
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75 FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\ |
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76 LAST_(symbol1,symbol2) ->last_line, LAST_(symbol1,symbol2) ->last_column);\ |
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77 fprintf(stderr, __VA_ARGS__); \ |
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78 fprintf(stderr, "\n"); \ |
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79 warning_found = true; \ |
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80 } |
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81 |
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82 |
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83 |
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84 /* NOTE: We create an independent visitor for this task instead of having this done by the remove_forward_dependencies_c |
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85 * because we do not want to handle the ***_pragma_c classes while doing this search. |
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86 * (remove_forward_dependencies_c needs to visit those classes when handling all the possible entries in |
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87 * library_c, and must have those visitors) |
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88 * |
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89 * NOTE: |
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90 * This class could have been written by visiting all the AST objects that could _reference_ a |
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91 * - FB type |
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92 * - Program type |
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93 * - Function type |
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94 * and by checking whether those references are in the declared_identifiers list. |
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95 * However, one of those objects, the ref_spec_c, may reference an FB type, or any other datatype, so we must have a way |
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96 * of knowing what is being referenced in this case. I have opted to introduce a new object type in the AST, the |
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97 * poutype_identifier_c, that will be used anywhere in the AST that references either a PROGRAM name or a FB type name |
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98 * or a FUNCTION name (previously a simple identifier_c was used!). |
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99 * This means that we merely need to visit the new poutype_identifier_c object in this visitor. |
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100 */ |
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101 class find_forward_dependencies_c: public search_visitor_c { |
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102 private: |
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103 identifiers_symbtable_t *declared_identifiers; // list of identifiers already declared by the symbols in the new tree |
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104 public: |
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105 find_forward_dependencies_c(identifiers_symbtable_t *declared_identifiers_) {declared_identifiers = declared_identifiers_;} |
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106 /*******************************************/ |
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107 /* B 1.1 - Letters, digits and identifiers */ |
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108 /*******************************************/ |
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109 // return NULL if the symbol is already in the declared_identifiers symbol table, otherwise return the missing symbol! |
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110 void *visit( poutype_identifier_c *symbol) |
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111 {if (declared_identifiers->find_value(symbol) != declared_identifiers->end_value()) return NULL; else return symbol;} |
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112 }; /* class find_forward_dependencies_c */ |
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113 |
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114 |
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115 |
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116 |
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117 /* A class to count the number of POUs (Function, FBs Programs and Configurations) in a library. |
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118 * This will be used to make sure whether we have copied all the POUs from the original AST (abstract |
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119 * syntax tree) to the new AST. |
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120 * Note that we can't simply use the number of 'elements' in the AST, as it may contain unknown/unsupported pragmas. |
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121 */ |
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122 class pou_count_c: public search_visitor_c { |
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123 private: |
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124 static pou_count_c *singleton; |
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125 long long int count; |
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126 |
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127 public: |
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128 static long long int get_count(library_c *library) { |
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129 if (NULL == singleton) singleton = new pou_count_c; |
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130 if (NULL == singleton) ERROR; |
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131 singleton->count = 0; |
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132 library->accept(*singleton); |
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133 return singleton->count; |
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134 } |
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135 |
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136 /**************************************/ |
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137 /* B.1.5 - Program organization units */ |
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138 /**************************************/ |
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139 void *visit( function_declaration_c *symbol) {count++; return NULL;} |
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140 void *visit(function_block_declaration_c *symbol) {count++; return NULL;} |
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141 void *visit( program_declaration_c *symbol) {count++; return NULL;} |
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142 void *visit( configuration_declaration_c *symbol) {count++; return NULL;} |
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143 }; /* class pou_count_c */ |
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144 |
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145 pou_count_c *pou_count_c::singleton = NULL; |
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146 symbol_c remove_forward_dependencies_c_null_symbol; |
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147 |
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148 |
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149 |
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150 |
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151 |
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152 |
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153 |
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154 |
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155 /************************************************************/ |
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156 /************************************************************/ |
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157 /****** The main class: Remove Forward Depencies *******/ |
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158 /************************************************************/ |
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159 /************************************************************/ |
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160 |
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161 // constructor & destructor |
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162 remove_forward_dependencies_c:: remove_forward_dependencies_c(void) { |
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163 find_forward_dependencies = new find_forward_dependencies_c(&declared_identifiers); |
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164 current_display_error_level = error_level_default; |
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165 error_count = 0; |
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166 } |
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167 |
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168 remove_forward_dependencies_c::~remove_forward_dependencies_c(void) { |
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169 delete find_forward_dependencies; |
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170 } |
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171 |
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172 |
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173 int remove_forward_dependencies_c::get_error_count(void) { |
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174 return error_count; |
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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 library_c *remove_forward_dependencies_c::create_new_tree(symbol_c *tree) { |
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180 library_c *old_tree = dynamic_cast<library_c *>(tree); |
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181 if (NULL == old_tree) ERROR; |
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182 new_tree = new library_c; |
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183 *((symbol_c *)new_tree) = *((symbol_c *)tree); // copy any annotations from tree to new_tree; |
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184 new_tree->clear(); // remove all elements from list. |
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185 tree->accept(*this); |
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186 return new_tree; |
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187 } |
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188 |
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189 |
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190 |
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191 void *remove_forward_dependencies_c::handle_library_symbol(symbol_c *symbol, symbol_c *name, symbol_c *search1, symbol_c *search2, symbol_c *search3) { |
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192 if (inserted_symbols.find(symbol) != inserted_symbols.end()) return NULL; // already previously inserted into new_tree and declared_identifiers. Do not handle again! |
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193 if ((search1 != NULL) && (search1->accept(*find_forward_dependencies) != NULL)) return NULL; // A forward depency has not yet been satisfied. Wait for a later iteration to try again! |
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194 if ((search2 != NULL) && (search2->accept(*find_forward_dependencies) != NULL)) return NULL; // A forward depency has not yet been satisfied. Wait for a later iteration to try again! |
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195 if ((search3 != NULL) && (search3->accept(*find_forward_dependencies) != NULL)) return NULL; // A forward depency has not yet been satisfied. Wait for a later iteration to try again! |
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196 /* no forward dependencies found => insert into new AST, and add to the 'defined identifiers' and 'inserted symbol' lists */ |
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197 if (declared_identifiers.find_value(name) == declared_identifiers.end_value()) |
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198 declared_identifiers.insert(name, NULL); // only add if not yet in the symbol table (an overloaded version of this same POU could have been inderted previously!) |
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199 inserted_symbols.insert(symbol); |
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200 new_tree->add_element(current_code_generation_pragma); |
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201 new_tree->add_element(symbol); |
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202 return NULL; |
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203 } |
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204 |
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205 |
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206 /* Tell the user that the source code contains a circular dependency */ |
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207 void remove_forward_dependencies_c::print_circ_error(library_c *symbol) { |
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208 /* Note that we only print Functions and FBs, as Programs and Configurations cannot contain circular references due to syntax rules */ |
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209 /* Note too that circular references in derived datatypes is also not possible due to sytax! */ |
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210 int initial_error_count = error_count; |
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211 for (int i = 0; i < symbol->n; i++) |
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212 if ( (inserted_symbols.find(symbol->elements[i]) == inserted_symbols.end()) // if not copied to new AST |
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213 &&( (NULL != dynamic_cast <function_block_declaration_c *>(symbol->elements[i])) // and (is a FB |
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214 ||(NULL != dynamic_cast < function_declaration_c *>(symbol->elements[i])))) // or a Function) |
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215 STAGE3_ERROR(0, symbol->elements[i], symbol->elements[i], "POU (%s) contains a self-reference and/or belongs in a circular referencing loop", get_datatype_info_c::get_id_str(symbol->elements[i])); |
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216 if (error_count == initial_error_count) ERROR; // We were unable to determine which POUs contain the circular references!! |
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217 } |
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218 |
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219 |
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220 /***************************/ |
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221 /* B 0 - Programming Model */ |
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222 /***************************/ |
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223 /* enumvalue_symtable is filled in by enum_declaration_check_c, during stage3 semantic verification, with a list of all enumerated constants declared inside this POU */ |
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224 // SYM_LIST(library_c, enumvalue_symtable_t enumvalue_symtable;) |
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225 void *remove_forward_dependencies_c::visit(library_c *symbol) { |
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226 /* this method is the expected entry point for this visitor, and implements the main algorithm of the visitor */ |
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227 |
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228 /* first insert all the derived datatype declarations, in the same order by which they are delcared in the original AST */ |
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229 /* Since IEC 61131-3 does not allow FBs in arrays or structures, it is actually safe to place all the datatypes before all the POUs! */ |
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230 for (int i = 0; i < symbol->n; i++) |
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231 if (NULL != dynamic_cast <data_type_declaration_c *>(symbol->elements[i])) |
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232 new_tree->add_element(symbol->elements[i]); |
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233 |
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234 /* now do the POUs, in whatever order is necessary to guarantee no forward references. */ |
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235 long long int old_tree_pou_count = pou_count_c::get_count(symbol); |
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236 // if no code generation pragma exists before the first entry in the library, the default is to enable code generation. |
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237 enable_code_generation_pragma_c *default_code_generation_pragma = new enable_code_generation_pragma_c; |
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238 int prev_n; |
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239 cycle_count = 0; |
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240 do { |
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241 cycle_count++; |
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242 prev_n = new_tree->n; |
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243 current_code_generation_pragma = default_code_generation_pragma; |
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244 for (int i = 0; i < symbol->n; i++) symbol->elements[i]->accept(*this); |
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245 } while (prev_n != new_tree->n); // repeat while new elementns are still being added to the new AST |
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246 |
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247 if (old_tree_pou_count != pou_count_c::get_count(new_tree)) |
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248 print_circ_error(symbol); |
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249 |
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250 return NULL; |
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251 } |
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252 |
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253 |
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254 /**************************************/ |
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255 /* B.1.5 - Program organization units */ |
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256 /**************************************/ |
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257 /***********************/ |
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258 /* B 1.5.1 - Functions */ |
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259 /***********************/ |
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260 // SYM_REF4(function_declaration_c, derived_function_name, type_name, var_declarations_list, function_body, enumvalue_symtable_t enumvalue_symtable;) |
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261 void *remove_forward_dependencies_c::visit(function_declaration_c *symbol) |
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262 {return handle_library_symbol(symbol, symbol->derived_function_name, symbol->type_name, symbol->var_declarations_list, symbol->function_body);} |
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263 /*****************************/ |
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264 /* B 1.5.2 - Function Blocks */ |
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265 /*****************************/ |
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266 /* FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */ |
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267 // SYM_REF3(function_block_declaration_c, fblock_name, var_declarations, fblock_body, enumvalue_symtable_t enumvalue_symtable;) |
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268 void *remove_forward_dependencies_c::visit(function_block_declaration_c *symbol) |
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269 {return handle_library_symbol(symbol, symbol->fblock_name, symbol->var_declarations, symbol->fblock_body);} |
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270 /**********************/ |
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271 /* B 1.5.3 - Programs */ |
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272 /**********************/ |
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273 /* PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */ |
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274 // SYM_REF3(program_declaration_c, program_type_name, var_declarations, function_block_body, enumvalue_symtable_t enumvalue_symtable;) |
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275 void *remove_forward_dependencies_c::visit(program_declaration_c *symbol) |
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276 {return handle_library_symbol(symbol, symbol->program_type_name, symbol->var_declarations, symbol->function_block_body);} |
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277 /********************************/ |
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278 /* B 1.7 Configuration elements */ |
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279 /********************************/ |
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280 /* CONFIGURATION configuration_name (...) END_CONFIGURATION */ |
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281 // SYM_REF5(configuration_declaration_c, configuration_name, global_var_declarations, resource_declarations, access_declarations, instance_specific_initializations, enumvalue_symtable_t enumvalue_symtable;) |
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282 void *remove_forward_dependencies_c::visit(configuration_declaration_c *symbol) |
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283 {return handle_library_symbol(symbol, symbol->configuration_name, symbol->global_var_declarations, symbol->resource_declarations, symbol->access_declarations);} |
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284 /********************/ |
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285 /* 2.1.6 - Pragmas */ |
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286 /********************/ |
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287 void *remove_forward_dependencies_c::visit(disable_code_generation_pragma_c *symbol) {current_code_generation_pragma = symbol; return NULL;} |
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288 void *remove_forward_dependencies_c::visit( enable_code_generation_pragma_c *symbol) {current_code_generation_pragma = symbol; return NULL;} |
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289 /* I have no ideia what this pragma is. Where should we place it in the re-ordered tree? |
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290 * Without knowing the semantics of the pragma, it is not possible to hande it correctly. |
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291 * We therefore print out an error message, and abort! |
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292 */ |
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293 // TODO: print error message! |
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294 void *remove_forward_dependencies_c::visit(pragma_c *symbol) { |
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295 if (1 != cycle_count) return NULL; // only handle unknown pragmas in the first cycle! |
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296 STAGE3_WARNING(symbol, symbol, "Unrecognized pragma. Including the pragma when using the '-p' command line option for 'allow use of forward references' may result in unwanted behaviour."); |
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297 new_tree->add_element(symbol); |
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298 return NULL; |
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299 } |
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300 |
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301 |
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302 |
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303 |