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 

    94   private:

    95     void* handle_param_list(list_c *list) {

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

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

    98 

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

   100       param_count += list->n;

   101      return NULL;

   102     }

   103 

   104     void* handle_single_param(symbol_c *var_name) {

   105       param_count++;

   106       if (next_param == param_count)

   107         return var_name;

   108 

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

   110      return NULL;

   111     }

   112 

   113     void* iterate_list(list_c *list) {

   114       void *res;

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

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

   117 	if (res != NULL)

   118 	  return res;

   119       }

   120       return NULL;

   121    }

   122 

   123 

   124   public:

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

   126     void reset(void) {

   127       next_param = param_count = 0;

   128       current_param_name = NULL;

   129       current_param_type = current_param_default_value = NULL;

   130     }

   131 

   132     /* initialise the iterator object.

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

   134      * that will be analysed...

   135      */

   136     function_param_iterator_c(function_declaration_c *f_decl) {

   137       this->f_decl = f_decl;

   138       reset();

   139     }

   140 

   141     /* initialise the iterator object.

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

   143      * that will be analysed...

   144      */

   145     function_param_iterator_c(function_block_declaration_c *fb_decl) {

   146       this->f_decl = fb_decl;

   147       reset();

   148     }

   149 

   150     /* initialise the iterator object.

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

   152      * that will be analysed...

   153      */

   154     function_param_iterator_c(program_declaration_c *p_decl) {

   155       this->f_decl = p_decl;

   156       reset();

   157     }

   158 

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

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

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

   162      * reference the first parameter...

   163      *

   164      * Returns the parameter's name!

   165      */

   166     identifier_c *next(void) {

   167       void *res;

   168       param_count = 0;

   169       next_param++;

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

   171       if (res == NULL)

   172         return NULL;

   173 

   174       symbol_c *sym = (symbol_c *)res;

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

   176       if (identifier == NULL)

   177         ERROR;

   178 

   179       current_param_name = identifier;

   180       return current_param_name;

   181     }

   182 

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

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

   185      */

   186     symbol_c *default_value(void) {

   187       return current_param_default_value;

   188     }

   189 

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

   191     symbol_c *param_type(void) {

   192       return current_param_type;

   193     }

   194 

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

   196      * i.e. VAR_INPUT, VAR_OUTPUT or VAR_INOUT

   197      */

   198     param_direction_t param_direction(void) {

   199       return current_param_direction;

   200     }

   201 

   202 /******************************************/

   203 /* B 1.4.3 - Declaration & Initialisation */

   204 /******************************************/

   205     void *visit(input_declarations_c *symbol) {

   206       TRACE("input_declarations_c");

   207       current_param_direction = direction_in;

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

   209     }

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

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

   212 

   213 #if 0

   214 /* var1_list ':' array_spec_init */

   215 SYM_REF2(array_var_init_decl_c, var1_list, array_spec_init)

   216 

   217 /*  var1_list ':' initialized_structure */

   218 SYM_REF2(structured_var_init_decl_c, var1_list, initialized_structure)

   219 

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

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

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

   223 

   224 /* name_list ',' fb_name */

   225 SYM_LIST(fb_name_list_c)

   226 #endif

   227 

   228     void *visit(output_declarations_c *symbol) {

   229       TRACE("output_declarations_c");

   230       current_param_direction = direction_out;

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

   232     }

   233     void *visit(input_output_declarations_c *symbol) {

   234       TRACE("input_output_declarations_c");

   235       current_param_direction = direction_inout;

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

   237     }

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

   239 

   240 #if 0

   241 /*  var1_list ':' array_specification */

   242 SYM_REF2(array_var_declaration_c, var1_list, array_specification)

   243 

   244 /*  var1_list ':' structure_type_name */

   245 SYM_REF2(structured_var_declaration_c, var1_list, structure_type_name)

   246 #endif

   247 

   248 /* VAR [CONSTANT] var_init_decl_list END_VAR */

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

   250 

   251 #if 0

   252 /*  VAR RETAIN var_init_decl_list END_VAR */

   253 SYM_REF2(retentive_var_declarations_c, var_init_decl_list, unused)

   254 

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

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

   257 SYM_REF2(located_var_declarations_c, option, located_var_decl_list)

   258 

   259 /* helper symbol for located_var_declarations */

   260 /* located_var_decl_list located_var_decl ';' */

   261 SYM_LIST(located_var_decl_list_c)

   262 

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

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

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

   266 #endif

   267 

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

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

   270 // SYM_REF2(external_var_declarations_c, option, external_declaration_list)

   271     void *visit(external_var_declarations_c *symbol) {

   272       TRACE("external_var_declarations_c");

   273       current_param_direction = direction_extref;

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

   275     }

   276 

   277 /* helper symbol for external_var_declarations */

   278 /*| external_declaration_list external_declaration';' */

   279 // SYM_LIST(external_declaration_list_c)

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

   281 

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

   283 //SYM_REF2(external_declaration_c, global_var_name, specification)

   284     void *visit(external_declaration_c *symbol) {

   285       TRACE("external_declaration_c");

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

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

   288        * variable list we will be analysing, the current_param_XXXX

   289        * variables will get overwritten when we visit the next

   290        * var1_init_decl_c list!

   291        */

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

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

   294 

   295       return handle_single_param(symbol->global_var_name);

   296     }

   297 

   298 

   299 #if 0

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

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

   302 SYM_REF2(global_var_declarations_c, option, global_var_decl_list)

   303 

   304 /* helper symbol for global_var_declarations */

   305 /*| global_var_decl_list global_var_decl ';' */

   306 SYM_LIST(global_var_decl_list_c)

   307 

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

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

   310 SYM_REF2(global_var_decl_c, global_var_spec, type_specification)

   311 

   312 /*| global_var_name location */

   313 SYM_REF2(global_var_spec_c, global_var_name, location)

   314 

   315 /*  AT direct_variable */

   316 SYM_REF2(location_c, direct_variable, unused)

   317 

   318 /*| global_var_list ',' global_var_name */

   319 SYM_LIST(global_var_list_c)

   320 

   321 /*  var1_list ':' single_byte_string_spec */

   322 SYM_REF2(single_byte_string_var_declaration_c, var1_list, single_byte_string_spec)

   323 

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

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

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

   327 SYM_REF2(single_byte_string_spec_c, integer, single_byte_character_string)

   328 

   329 /*  var1_list ':' double_byte_string_spec */

   330 SYM_REF2(double_byte_string_var_declaration_c, var1_list, double_byte_string_spec)

   331 

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

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

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

   335 SYM_REF2(double_byte_string_spec_c, integer, double_byte_character_string)

   336 

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

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

   339 SYM_REF2(incompl_located_var_declarations_c, option, incompl_located_var_decl_list)

   340 

   341 /* helper symbol for incompl_located_var_declarations */

   342 /*| incompl_located_var_decl_list incompl_located_var_decl ';' */

   343 SYM_LIST(incompl_located_var_decl_list_c)

   344 

   345 /*  variable_name incompl_location ':' var_spec */

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

   347 

   348 /*  AT incompl_location_token */

   349 SYM_TOKEN(incompl_location_c)

   350 #endif

   351 

   352 

   353     void *visit(var1_init_decl_c *symbol) {

   354       TRACE("var1_init_decl_c");

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

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

   357        * variable list we will be analysing, the current_param_XXXX

   358        * variables will get overwritten when we visit the next

   359        * var1_init_decl_c list!

   360        */

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

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

   363 

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

   365     }

   366 

   367 

   368 

   369     void *visit(var1_list_c *symbol) {

   370       TRACE("var1_list_c");

   371       return handle_param_list(symbol);

   372     }

   373 

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

   375 

   376 

   377 /***********************/

   378 /* B 1.5.1 - Functions */

   379 /***********************/

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

   381     /* intermediate helper symbol for function_declaration */

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

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

   384 

   385 

   386 /*****************************/

   387 /* B 1.5.2 - Function Blocks */

   388 /*****************************/

   389 /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

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

   391 

   392 /* intermediate helper symbol for function_declaration */

   393 /*  { io_var_declarations | other_var_declarations }   */

   394 /*

   395  * NOTE: we re-use the var_declarations_list_c

   396  */

   397 

   398 /*  VAR_TEMP temp_var_decl_list END_VAR */

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

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

   401 

   402 /*  VAR NON_RETAIN var_init_decl_list END_VAR */

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

   404 

   405 

   406 /**********************/

   407 /* B 1.5.3 - Programs */

   408 /**********************/

   409 /*  PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */

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

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

   412 

   413 /* intermediate helper symbol for program_declaration_c */

   414 /*  { io_var_declarations | other_var_declarations }   */

   415 /*

   416  * NOTE: we re-use the var_declarations_list_c

   417  */

   418 

   419 };

   420 

   421 

   422 

   423 

   424 

   425 

   426