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7 The following compiler has been based on the |
7 The following compiler has been based on the |
8 FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10) |
8 FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10) |
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11 Copyright (C) 2003-2011 Mario de Sousa (msousa@fe.up.pt) |
11 Copyright (C) 2003-2012 Mario de Sousa (msousa@fe.up.pt) |
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13 |
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14 **************************************************************** |
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15 **************************************************************** |
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16 **************************************************************** |
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17 ********* ********* |
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18 ********* ********* |
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19 ********* O V E R A L L G O A L S ********* |
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20 ********* ********* |
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21 ********* ********* |
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22 **************************************************************** |
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23 **************************************************************** |
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27 |
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28 This project has the goal of producing an open source compiler for the programming languages defined |
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29 in the IEC 61131-3 standard. These programming languages are mostly used in the industrial automation |
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30 domain, to program PLCs (Programmable Logic Controllers). |
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31 |
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32 This standard defines 5 programming languages: |
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33 - IL : Instructtion List |
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34 A textual programming language, somewhat similar to assembly. |
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35 - ST : Structured Text |
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36 A textual programming language, somewhat similar to Pascal. |
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37 - FBD: Function Block Diagram |
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38 A graphical programming language, somewhat similar to an electrical circuit diagram based on small |
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39 scale integration ICs (Integrated Circuits) (counters, AND/OR/XOR/... logic gates, timers, ...). |
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40 - LD : Ladder Diagram |
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41 A graphical programming language, somewhat similar to an electrical circuit diagram based on |
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42 relays (used for basic cabled logic controllers). |
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43 - SFC: Sequential Function Chart |
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44 A graphical programming language, that defines a state machine, based largely on Grafcet. |
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45 (may also be expressed in textual format). |
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46 |
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47 Of the above 5 languages, the standard defines textual representations for IL, ST and SFC. |
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48 It is these 3 languages that we target, and we currently support all three, as long as they are |
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49 expressed in the textual format as defined in the standard. |
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50 |
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51 Currently the matiec project generates two compilers (more correctly, code translaters, but we like |
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52 to call them compilers :-O ): iec2c, and iec2iec |
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53 |
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54 Both compilers accept the same input: a text file with ST, IL and/or SFC code. |
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55 |
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56 The iec2c compiler generates ANSI C code which is equivalent to the IEC 61131-3 code expressed in the input file. |
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57 |
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58 The iec2iec compiler generates IEC61131-3 code which is equivalent to the IEC 61131-3 code expressed in the input file. |
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59 This last compiler should generate and output file which should be almost identical to the input file (some formating |
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60 may change, as well as the case of letters, etc.). This 'compiler' is mostly used by the matiec project contributors |
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61 to help debug the lexical and syntax portions of the compilers. |
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62 |
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63 |
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64 |
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65 To compile/build these compilers, just |
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66 $./configure; make |
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67 |
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68 |
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71 |
15 **************************************************************** |
72 **************************************************************** |
16 **************************************************************** |
73 **************************************************************** |
23 **************************************************************** |
80 **************************************************************** |
24 **************************************************************** |
81 **************************************************************** |
25 **************************************************************** |
82 **************************************************************** |
26 |
83 |
27 The compiler works in 4(+1) stages: |
84 The compiler works in 4(+1) stages: |
28 Stage 1 - Lexical analyser - implemented with flex (iec.flex) |
85 ================================== |
29 Stage 2 - Syntax parser - implemented with bison (iec.y) |
86 Stage 1 - Lexical analyser - implemented with flex (stage1_2/iec_flex.ll) |
30 Stage 3 - Semantics analyser - currently in its early stages |
87 Stage 2 - Syntax parser - implemented with bison (stage1_2/iec_bison.yy) |
31 Stage 4 - Code generator - implemented in C++ |
88 Stage pre3 - Populate symbol tables - Symbol tables that will ease searching for symbols in the abstract symbol tree. |
32 Stage 4+1 - Binary code generator - gcc, javac, etc... |
89 Stage 3 - Semantics analyser - currently does type checking only |
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90 Stage 4 - Code generator - generates ANSI C code |
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91 |
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92 Stage 5 - Binary code generator - gcc, javac, etc... (Not integrated into matiec compiler. Must be called explicitly by the user.) |
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93 |
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35 Data structures passed between stages, in global variables: |
96 Data structures passed between stages, in global variables: |
36 1->2 : tokens (int), and token values (char *) |
97 ========================================================== |
37 2->1 : symbol tables (defined in symtable.hh) |
98 1->2 : tokens (int), and token values (char *) (defined in stage1_2/stage1_2_priv.hh) |
38 2->3 : abstract syntax tree (tree of C++ classes, in absyntax.hh file) |
99 2->1 : symbol tables (implemented in util/symtable.[hh|cc], and defined in stage1_2/stage1_2_priv.hh) |
39 3->4 : Same as 2->3 |
100 2->3 : abstract syntax tree (tree of C++ objects, whose classes are defined in absyntax/absyntax.hh) |
40 4->4+1 : file with program in c, java, etc... |
101 pre3->3,4 : global symbol tables (defined in util/[d]symtable.[hh|cc] and declared in absyntax_utils/absyntax_utils.hh) |
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102 3->4 : abstract syntax tree (same as 2->3), but now annotated (i.e. some extra data inserted into the absyntax tree) |
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103 |
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104 4->5 : file with program in c, java, etc... |
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105 |
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43 The compiler works in several passes: |
109 The compiler works in several passes: |
44 Pass 1: executes stages 1 and 2 simultaneously |
110 ==================================== |
45 Pass 2: executes stage 3 |
111 |
46 Pass 3: executes stage 4 |
112 Stage 1 and Stage 2 |
47 Pass 4: executes stage 4+1 |
113 ------------------- |
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114 Executed in one single pass. This pass will: |
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115 - Do lexical analysis |
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116 - Do syntax analysis |
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117 - Execute the absyntax_utils/add_en_eno_param_decl_c visitor class |
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118 This class will add the EN and ENO parameter declarations to all |
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119 functions that do not have them already explicitly declared by the user. |
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120 This will let us handle these parameters in the remaining compiler just as if |
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121 they were standard input/output parameters. |
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122 |
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123 |
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124 Stage Pre3 |
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125 ---------- |
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126 Executed in one single pass. This pass will populate the following symbol tables: |
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127 - function_symtable; /* A symbol table with all globally declared functions POUs. */ |
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128 - function_block_type_symtable; /* A symbol table with all globally declared functions block POUs. */ |
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129 - program_type_symtable; /* A symbol table with all globally declared program POUs. */ |
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130 - type_symtable; /* A symbol table with all user declared (non elementary) datat type definitions. */ |
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131 - enumerated_value_symtable; /* A symbol table with all identifiers (values) declared for enumerated types. */ |
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132 |
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133 |
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134 Stage 3 |
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135 ------- |
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136 Executes two algorithms (flow control analysis, and data type analysis) in several passes. |
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137 |
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138 Flow control: |
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139 Pass 1: Does flow control analysis (for now only of IL code) |
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140 Implemented in -> stage3/flow_control_analysis_c |
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141 This will anotate the abstract syntax tree |
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142 (Every object of the class il_instruction_c that is in the abstract syntax tree will have the variable 'prev_il_instruction' correctly filled in.) |
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143 |
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144 Data Type Analysis |
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145 Pass 1: Analyses the possible data types each expression/literal/IL instruction/etc. may take |
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146 Implemented in -> stage3/fill_candidate_datatypes_c |
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147 This will anotate the abstract syntax tree |
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148 (Every object of in the abstract syntax tree that may have a data type, will have the variable 'candidate_datatypes' correctly filled in.) |
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149 Pass 2: Narrows all the possible data types each expression/literal/IL instruction/etc. may take down to a single data type |
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150 Implemented in -> stage3/narrow_candidate_datatypes_c |
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151 This will anotate the abstract syntax tree |
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152 (Every object of in the abstract syntax tree that may have a data type, will have the variable 'datatype' correctly filled in. |
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153 Additionally, objects in the abstract syntax tree that represen function invocations will have the variables |
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154 'called_function_declaration', 'extensible_param_count' and 'candidate_functions' correctly filled in. |
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155 Additionally, objects in the abstract syntax tree that represen function block (FB) invocations will have the variable |
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156 'called_fb_declaration' correctly filled in.) |
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157 Pass 2: Prints error messages in the event of the IEC 61131-3 source code being analysed contains semantic data type incompatibility errors. |
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158 Implemented in -> stage3/print_datatype_errors_c |
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159 |
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160 |
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161 Stage 4 |
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162 ------- |
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163 Has 2 possible implementations. |
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164 |
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165 iec2c : Generates C source code in a single pass (stage4/generate_c). |
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166 iec2iec: Generates IEC61131 source code in a single pass (stage4/generate_iec). |
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167 |
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171 |
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172 |
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173 **************************************************************** |
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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 ********* N O T E S ********* |
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179 ********* ********* |
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180 ********* ********* |
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181 **************************************************************** |
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182 **************************************************************** |
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183 **************************************************************** |
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50 NOTE 1 |
190 NOTE 1 |
51 ====== |
191 ====== |
52 Note that stage 2 passes data back to stage 1. This is only |
192 Note that stage 2 passes data back to stage 1. This is only |