1 /*

     2  * (c) 2003 Mario de Sousa

     3  *

     4  * Offered to the public under the terms of the GNU General Public License

     5  * as published by the Free Software Foundation; either version 2 of the

     6  * License, or (at your option) any later version.

     7  *

     8  * This program is distributed in the hope that it will be useful, but

     9  * WITHOUT ANY WARRANTY; without even the implied warranty of

    10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

    11  * Public License for more details.

    12  *

    13  * This code is made available on the understanding that it will not be

    14  * used in safety-critical situations without a full and competent review.

    15  */

    16 

    17 /*

    18  * An IEC 61131-3 IL and ST compiler.

    19  *

    20  * Based on the

    21  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

    22  *

    23  */

    24 

    25 

    26 /*

    27  * Function parameter iterator.

    28  * Iterate through the in/out parameters of a function declaration.

    29  * Function blocks are also suported.

    30  *

    31  * This is part of the 4th stage that generates

    32  * a c++ source program equivalent to the IL and ST

    33  * code.

    34  */

    35 

    36 

    37 

    38 

    39 

    40 

    41 //#include <stdio.h>  /* required for NULL */

    42 //#include <string>

    43 //#include <iostream>

    44 

    45 //#include "../../util/symtable.hh"

    46 

    47 //#include "generate_c.hh"

    48 

    49 

    50 #include "../../absyntax/visitor.hh"

    51 

    52 

    53 /* given a function_declaration_c, iterate through each

    54  * function in/out/inout parameter, returning the name

    55  * of each parameter...function_param_iterator_c

    56  */

    57 class function_param_iterator_c : public null_visitor_c {

    58   public:

    59     /* A type to specify the type of parameter.

    60      * VAR_INPUT => direction_in

    61      * VAR_OUTPUT => direction_out

    62      * VAR_IN_OUT => direction_inout

    63      * VAR_EXTERNAL => direction_extref

    64      *

    65      * Note that VAR_EXTERNAL declares variables that are in reality references

    66      * to global variables. This is used only inside programs!

    67      * These references to external variables must be correctly initialised to refer

    68      * to the correct global variable. Note that the user may define which variable is to be

    69      * referenced in a CONFIGURATION, and that different instantiations of a program

    70      * may have the same external variable reference diffenrent global variables!

    71      * The references must therefore be correctly initialised when the program instance

    72      * is created. This may be done by the PROGRAM class constructor since the ST and IL

    73      * languages do not allow the VAR_EXTERNAL reference to change at runtime

    74      * for a specific instance.

    75      *

    76      * We therefore need to call a PROGRAM class constructor with the variables

    77      * that should be refernced by the VAR_EXTERNAL variables. The direction_extref will

    78      * be used to identify these parameters!

    79      */

    80     typedef enum {direction_in, direction_out, direction_inout, direction_extref} param_direction_t ;

    81 

    82 

    83   private:

    84       /* a pointer to the function_block_declaration_c

    85        * or function_declaration_c currently being analysed.

    86        */

    87     symbol_c *f_decl;

    88     int next_param, param_count;

    89     identifier_c *current_param_name;

    90     symbol_c *current_param_type;

    91     symbol_c *current_param_default_value;

    92     param_direction_t current_param_direction;

    93     bool en_declared;

    94     bool eno_declared;

    95 

    96   private:

    97     void* handle_param_list(list_c *list) {

    98       if (next_param <= param_count + list->n)

    99         return list->elements[next_param - param_count - 1];

   100 

   101       /* the desired param is not on this list... */

   102       param_count += list->n;

   103      return NULL;

   104     }

   105 

   106     void* handle_single_param(symbol_c *var_name) {

   107       param_count++;

   108       if (next_param == param_count)

   109         return var_name;

   110 

   111       /* not yet the desired param... */

   112      return NULL;

   113     }

   114 

   115     void* iterate_list(list_c *list) {

   116       void *res;

   117       for (int i = 0; i < list->n; i++) {

   118         res = list->elements[i]->accept(*this);

   119         if (res != NULL)

   120 	        return res;

   121       }

   122       return NULL;

   123    }

   124 

   125 

   126   public:

   127     /* start off at the first parameter once again... */

   128     void reset(void) {

   129       next_param = param_count = 0;

   130       current_param_name = NULL;

   131       current_param_type = current_param_default_value = NULL;

   132       en_declared = false;

   133       eno_declared = false;

   134     }

   135 

   136     /* initialise the iterator object.

   137      * We must be given a reference to the function declaration

   138      * that will be analysed...

   139      */

   140     function_param_iterator_c(function_declaration_c *f_decl) {

   141       this->f_decl = f_decl;

   142       reset();

   143     }

   144 

   145     /* initialise the iterator object.

   146      * We must be given a reference to the function block declaration

   147      * that will be analysed...

   148      */

   149     function_param_iterator_c(function_block_declaration_c *fb_decl) {

   150       this->f_decl = fb_decl;

   151       reset();

   152     }

   153 

   154     /* initialise the iterator object.

   155      * We must be given a reference to the program declaration

   156      * that will be analysed...

   157      */

   158     function_param_iterator_c(program_declaration_c *p_decl) {

   159       this->f_decl = p_decl;

   160       reset();

   161     }

   162 

   163     /* Skip to the next parameter. After object creation,

   164      * the object references on parameter _before_ the first, so

   165      * this function must be called once to get the object to

   166      * reference the first parameter...

   167      *

   168      * Returns the parameter's name!

   169      */

   170     identifier_c *next(void) {

   171       void *res;

   172       identifier_c *identifier;

   173       param_count = 0;

   174       next_param++;

   175       res = f_decl->accept(*this);

   176       if (res != NULL) {

   177         symbol_c *sym = (symbol_c *)res;

   178         identifier = dynamic_cast<identifier_c *>(sym);

   179         if (identifier == NULL)

   180           ERROR;

   181       }

   182       else if (!en_declared) {

   183         current_param_direction = direction_in;

   184         identifier = declare_en_param();

   185       }

   186       else if (!eno_declared) {

   187         current_param_direction = direction_out;

   188         identifier = declare_eno_param();

   189       }

   190       else

   191         return NULL;

   192       

   193       current_param_name = identifier;

   194       return current_param_name;

   195     }

   196 

   197     identifier_c *declare_en_param(void) {

   198       en_declared = true;

   199       identifier_c *identifier = new identifier_c("EN");

   200       current_param_type = (symbol_c*)(new bool_type_name_c());

   201       current_param_default_value = (symbol_c*)(new boolean_literal_c(current_param_type, new boolean_true_c()));

   202       return identifier;

   203     }

   204 

   205     identifier_c *declare_eno_param(void) {

   206       eno_declared = true;

   207       identifier_c *identifier = new identifier_c("ENO");

   208       current_param_type = (symbol_c*)(new bool_type_name_c());

   209       current_param_default_value = NULL;

   210       return identifier;

   211     }

   212 

   213     /* Returns the currently referenced parameter's default value,

   214      * or NULL if none is specified in the function declrataion itself.

   215      */

   216     symbol_c *default_value(void) {

   217       return current_param_default_value;

   218     }

   219 

   220     /* Returns the currently referenced parameter's type name. */

   221     symbol_c *param_type(void) {

   222       return current_param_type;

   223     }

   224 

   225     /* Returns the currently referenced parameter's data passing direction.

   226      * i.e. VAR_INPUT, VAR_OUTPUT or VAR_INOUT

   227      */

   228     param_direction_t param_direction(void) {

   229       return current_param_direction;

   230     }

   231 

   232 /******************************************/

   233 /* B 1.4.3 - Declaration & Initialisation */

   234 /******************************************/

   235     void *visit(input_declarations_c *symbol) {

   236       TRACE("input_declarations_c");

   237       current_param_direction = direction_in;

   238       return symbol->input_declaration_list->accept(*this);

   239     }

   240     void *visit(input_declaration_list_c *symbol) {TRACE("input_declaration_list_c"); return iterate_list(symbol);}

   241     void *visit(edge_declaration_c *symbol) {TRACE("edge_declaration_c"); return symbol->var1_list->accept(*this);}

   242     void *visit(en_param_declaration_c *symbol) {

   243       TRACE("en_param_declaration_c");

   244       if (en_declared) ERROR;

   245       return (void *)declare_en_param();

   246     }

   247 

   248     /* var1_list ':' array_spec_init */

   249     //SYM_REF2(array_var_init_decl_c, var1_list, array_spec_init)

   250     void *visit(array_var_init_decl_c *symbol) {TRACE("array_var_init_decl_c"); return symbol->var1_list->accept(*this);}

   251     

   252     /*  var1_list ':' initialized_structure */

   253     //SYM_REF2(structured_var_init_decl_c, var1_list, initialized_structure)

   254     void *visit(structured_var_init_decl_c *symbol) {TRACE("structured_var_init_decl_c"); return symbol->var1_list->accept(*this);}

   255     

   256 #if 0

   257 /* name_list ':' function_block_type_name ASSIGN structure_initialization */

   258 /* structure_initialization -> may be NULL ! */

   259 SYM_REF4(fb_name_decl_c, fb_name_list, function_block_type_name, structure_initialization, unused)

   260 

   261 /* name_list ',' fb_name */

   262 SYM_LIST(fb_name_list_c)

   263 #endif

   264 

   265     void *visit(output_declarations_c *symbol) {

   266       TRACE("output_declarations_c");

   267       current_param_direction = direction_out;

   268       return symbol->var_init_decl_list->accept(*this);

   269     }

   270     void *visit(eno_param_declaration_c *symbol) {

   271       TRACE("eno_param_declaration_c");

   272       if (eno_declared) ERROR;

   273       return (void *)declare_eno_param();

   274     }

   275     void *visit(input_output_declarations_c *symbol) {

   276       TRACE("input_output_declarations_c");

   277       current_param_direction = direction_inout;

   278       return symbol->var_declaration_list->accept(*this);

   279     }

   280     void *visit(var_declaration_list_c *symbol) {TRACE("var_declaration_list_c"); return iterate_list(symbol);}

   281 

   282 

   283     /*  var1_list ':' array_specification */

   284     //SYM_REF2(array_var_declaration_c, var1_list, array_specification)

   285     void *visit(array_var_declaration_c *symbol) {TRACE("array_var_declaration_c"); return symbol->var1_list->accept(*this);}

   286 

   287     /*  var1_list ':' structure_type_name */

   288     //SYM_REF2(structured_var_declaration_c, var1_list, structure_type_name)

   289     void *visit(structured_var_declaration_c *symbol) {TRACE("structured_var_declaration_c"); return symbol->var1_list->accept(*this);}

   290 

   291     /* VAR [CONSTANT] var_init_decl_list END_VAR */

   292     void *visit(var_declarations_c *symbol) {TRACE("var_declarations_c"); return NULL;}

   293 

   294 #if 0

   295 /*  VAR RETAIN var_init_decl_list END_VAR */

   296 SYM_REF2(retentive_var_declarations_c, var_init_decl_list, unused)

   297 

   298 /*  VAR [CONSTANT|RETAIN|NON_RETAIN] located_var_decl_list END_VAR */

   299 /* option -> may be NULL ! */

   300 SYM_REF2(located_var_declarations_c, option, located_var_decl_list)

   301 

   302 /* helper symbol for located_var_declarations */

   303 /* located_var_decl_list located_var_decl ';' */

   304 SYM_LIST(located_var_decl_list_c)

   305 

   306 /*  [variable_name] location ':' located_var_spec_init */

   307 /* variable_name -> may be NULL ! */

   308 SYM_REF4(located_var_decl_c, variable_name, location, located_var_spec_init, unused)

   309 #endif

   310 

   311 /*| VAR_EXTERNAL [CONSTANT] external_declaration_list END_VAR */

   312 /* option -> may be NULL ! */

   313 // SYM_REF2(external_var_declarations_c, option, external_declaration_list)

   314     void *visit(external_var_declarations_c *symbol) {

   315       TRACE("external_var_declarations_c");

   316       current_param_direction = direction_extref;

   317       return symbol->external_declaration_list->accept(*this);

   318     }

   319 

   320 /* helper symbol for external_var_declarations */

   321 /*| external_declaration_list external_declaration';' */

   322 // SYM_LIST(external_declaration_list_c)

   323     void *visit(external_declaration_list_c *symbol) {TRACE("external_declaration_list_c"); return iterate_list(symbol);}

   324 

   325 /*  global_var_name ':' (simple_specification|subrange_specification|enumerated_specification|array_specification|prev_declared_structure_type_name|function_block_type_name */

   326 //SYM_REF2(external_declaration_c, global_var_name, specification)

   327     void *visit(external_declaration_c *symbol) {

   328       TRACE("external_declaration_c");

   329       /* It is OK to store these values in the current_param_XXX

   330        * variables, because if the desired parameter is not in the

   331        * variable list we will be analysing, the current_param_XXXX

   332        * variables will get overwritten when we visit the next

   333        * var1_init_decl_c list!

   334        */

   335       current_param_default_value = spec_init_sperator_c::get_init(symbol->specification);

   336       current_param_type = spec_init_sperator_c::get_spec(symbol->specification);

   337 

   338       return handle_single_param(symbol->global_var_name);

   339     }

   340 

   341 

   342 #if 0

   343 /*| VAR_GLOBAL [CONSTANT|RETAIN] global_var_decl_list END_VAR */

   344 /* option -> may be NULL ! */

   345 SYM_REF2(global_var_declarations_c, option, global_var_decl_list)

   346 

   347 /* helper symbol for global_var_declarations */

   348 /*| global_var_decl_list global_var_decl ';' */

   349 SYM_LIST(global_var_decl_list_c)

   350 

   351 /*| global_var_spec ':' [located_var_spec_init|function_block_type_name] */

   352 /* type_specification ->may be NULL ! */

   353 SYM_REF2(global_var_decl_c, global_var_spec, type_specification)

   354 

   355 /*| global_var_name location */

   356 SYM_REF2(global_var_spec_c, global_var_name, location)

   357 

   358 /*  AT direct_variable */

   359 SYM_REF2(location_c, direct_variable, unused)

   360 

   361 /*| global_var_list ',' global_var_name */

   362 SYM_LIST(global_var_list_c)

   363 

   364 /*  var1_list ':' single_byte_string_spec */

   365 SYM_REF2(single_byte_string_var_declaration_c, var1_list, single_byte_string_spec)

   366 

   367 /*  STRING ['[' integer ']'] [ASSIGN single_byte_character_string] */

   368 /* integer ->may be NULL ! */

   369 /* single_byte_character_string ->may be NULL ! */

   370 SYM_REF2(single_byte_string_spec_c, integer, single_byte_character_string)

   371 

   372 /*  var1_list ':' double_byte_string_spec */

   373 SYM_REF2(double_byte_string_var_declaration_c, var1_list, double_byte_string_spec)

   374 

   375 /*  WSTRING ['[' integer ']'] [ASSIGN double_byte_character_string] */

   376 /* integer ->may be NULL ! */

   377 /* double_byte_character_string ->may be NULL ! */

   378 SYM_REF2(double_byte_string_spec_c, integer, double_byte_character_string)

   379 

   380 /*| VAR [RETAIN|NON_RETAIN] incompl_located_var_decl_list END_VAR */

   381 /* option ->may be NULL ! */

   382 SYM_REF2(incompl_located_var_declarations_c, option, incompl_located_var_decl_list)

   383 

   384 /* helper symbol for incompl_located_var_declarations */

   385 /*| incompl_located_var_decl_list incompl_located_var_decl ';' */

   386 SYM_LIST(incompl_located_var_decl_list_c)

   387 

   388 /*  variable_name incompl_location ':' var_spec */

   389 SYM_REF4(incompl_located_var_decl_c, variable_name, incompl_location, var_spec, unused)

   390 

   391 /*  AT incompl_location_token */

   392 SYM_TOKEN(incompl_location_c)

   393 #endif

   394 

   395 

   396     void *visit(var1_init_decl_c *symbol) {

   397       TRACE("var1_init_decl_c");

   398       /* It is OK to store these values in the current_param_XXX

   399        * variables, because if the desired parameter is not in the

   400        * variable list we will be analysing, the current_param_XXXX

   401        * variables will get overwritten when we visit the next

   402        * var1_init_decl_c list!

   403        */

   404       current_param_default_value = spec_init_sperator_c::get_init(symbol->spec_init);

   405       current_param_type = spec_init_sperator_c::get_spec(symbol->spec_init);

   406 

   407       return symbol->var1_list->accept(*this);

   408     }

   409 

   410 

   411 

   412     void *visit(var1_list_c *symbol) {

   413       TRACE("var1_list_c");

   414       return handle_param_list(symbol);

   415     }

   416 

   417     void *visit(var_init_decl_list_c *symbol) {TRACE("var_init_decl_list_c"); return iterate_list(symbol);}

   418 

   419 

   420 /***********************/

   421 /* B 1.5.1 - Functions */

   422 /***********************/

   423     void *visit(function_declaration_c *symbol) {TRACE("function_declaration_c"); return symbol->var_declarations_list->accept(*this);}

   424     /* intermediate helper symbol for function_declaration */

   425     void *visit(var_declarations_list_c *symbol) {TRACE("var_declarations_list_c"); return iterate_list(symbol);}

   426     void *visit(function_var_decls_c *symbol) {TRACE("function_var_decls_c"); /* ignore */ return NULL;}

   427 

   428 

   429 /*****************************/

   430 /* B 1.5.2 - Function Blocks */

   431 /*****************************/

   432 /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

   433     void *visit(function_block_declaration_c *symbol) {TRACE("function_block_declaration_c"); return symbol->var_declarations->accept(*this);}

   434 

   435 /* intermediate helper symbol for function_declaration */

   436 /*  { io_var_declarations | other_var_declarations }   */

   437 /*

   438  * NOTE: we re-use the var_declarations_list_c

   439  */

   440 

   441 /*  VAR_TEMP temp_var_decl_list END_VAR */

   442     void *visit(temp_var_decls_c *symbol) {TRACE("temp_var_decls_c"); /* ignore */ return NULL;}

   443     void *visit(temp_var_decls_list_c *symbol) {TRACE("temp_var_decls_list_c"); /* ignore */ return NULL;}

   444 

   445 /*  VAR NON_RETAIN var_init_decl_list END_VAR */

   446     void *visit(non_retentive_var_decls_c *symbol) {TRACE("non_retentive_var_decls_c"); /* ignore */ return NULL;}

   447 

   448 

   449 /**********************/

   450 /* B 1.5.3 - Programs */

   451 /**********************/

   452 /*  PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */

   453 // SYM_REF4(program_declaration_c, program_type_name, var_declarations, function_block_body, unused)

   454     void *visit(program_declaration_c *symbol) {TRACE("program_declaration_c"); return symbol->var_declarations->accept(*this);}

   455 

   456 /* intermediate helper symbol for program_declaration_c */

   457 /*  { io_var_declarations | other_var_declarations }   */

   458 /*

   459  * NOTE: we re-use the var_declarations_list_c

   460  */

   461 

   462 };

   463 

   464 

   465 

   466 

   467 

   468 

   469