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  * Conversion of il statements (i.e. IL code).

    28  *

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

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

    31  * code.

    32  */

    33 

    34 

    35 

    36 

    37 /***********************************************************************/

    38 /***********************************************************************/

    39 /***********************************************************************/

    40 /***********************************************************************/

    41 

    42 /* Returns the data type of an il_operand.

    43  *

    44  * Note that the il_operand may be a variable, in which case

    45  * we return the type of the variable instance.

    46  * The il_operand may also be a constant, in which case

    47  * we return the data type of that constant.

    48  *

    49  * The variable instance may be a member of a structured variable,

    50  * or an element in an array, or any combination of the two.

    51  *

    52  * The class constructor must be given the search scope

    53  * (function, function block or program within which

    54  * the possible il_operand variable instance was declared).

    55  */

    56 class search_il_operand_type_c {

    57 

    58   private:

    59     search_varfb_instance_type_c search_varfb_instance_type;

    60     search_constant_type_c search_constant_type;

    61 

    62   public:

    63     search_il_operand_type_c(symbol_c *search_scope): search_varfb_instance_type(search_scope) {}

    64 

    65   public:

    66     symbol_c *get_type(symbol_c *il_operand) {

    67       symbol_c *res;

    68 

    69       /* We first assume that it is a constant... */

    70       res = search_constant_type.get_type(il_operand);

    71       if (res != NULL) return res;

    72 

    73       /* Nope, now we assume it is a variable, and determine its type... */

    74       res = search_varfb_instance_type.get_type(il_operand);

    75       if (NULL != res) return res;

    76 

    77       /* not found */

    78       return NULL;

    79     }

    80 };

    81 

    82 

    83 

    84 /***********************************************************************/

    85 /***********************************************************************/

    86 /***********************************************************************/

    87 /***********************************************************************/

    88 

    89 

    90 /* A new class to ouput the il default variable to c++ code

    91  * We use this class, inheriting from symbol_c, so it may be used

    92  * as any other symbol_c object in the intermediate parse tree,

    93  * more specifically, so it can be used as any other il operand.

    94  * This makes the rest of the code much easier...

    95  *

    96  * Nevertheless, the basic visitor class visitor_c does not know

    97  * how to visit this new il_default_variable_c class, so we have

    98  * to extend that too.

    99  * In reality extending the basic symbols doesn't quite work out

   100  * as cleanly as desired (we need to use dynamic_cast in the

   101  * accept method of the il_default_variable_c), but it is cleaner

   102  * than the alternative...

   103  */

   104 class il_default_variable_c;

   105 

   106 /* This visitor class is not really required, we could place the

   107  * visit() method directly in genertae_cc_il_c, but doing it in

   108  * a seperate class makes the architecture more evident...

   109  */

   110 class il_default_variable_visitor_c {

   111   public:

   112     virtual void *visit(il_default_variable_c *symbol) = 0;

   113 

   114     virtual ~il_default_variable_visitor_c(void) {return;}

   115 };

   116 

   117 

   118 /* A class to print out to the resulting C++ code

   119  * the IL default variable name.

   120  *

   121  * It includes a reference to its name,

   122  * and the data type of the data currently stored

   123  * in this C++ variable... This is required because the

   124  * C++ variable is a union, and we must know which member

   125  * of the union top reference!!

   126  *

   127  * Note that we also need to keep track of the data type of

   128  * the value currently being stored in the default variable.

   129  * This is required so we can process parenthesis,

   130  *

   131  * e.g. :

   132  *         LD var1

   133  *         AND (

   134  *         LD var2

   135  *         OR var3

   136  *         )

   137  *

   138  * Note that we only execute the 'AND (' operation when we come across

   139  * the ')', i.e. once we have evaluated the result of the

   140  * instructions inside the parenthesis.

   141  * When we do execute the 'AND (' operation, we need to know the data type

   142  * of the operand, which in this case is the result of the evaluation of the

   143  * instruction list inside the parenthesis. We can only know this if we

   144  * keep track of the data type currently stored in the default variable!

   145  *

   146  * We use the current_type inside the generate_cc_il::default_variable_name variable

   147  * to track this!

   148  */

   149 class il_default_variable_c: public symbol_c {

   150   public:

   151     symbol_c *var_name;  /* in principle, this should point to an indentifier_c */

   152     symbol_c *current_type;

   153 

   154   public:

   155     il_default_variable_c(const char *var_name_str, symbol_c *current_type);

   156     virtual void *accept(visitor_c &visitor);

   157 };

   158 

   159 

   160 /***********************************************************************/

   161 /***********************************************************************/

   162 /***********************************************************************/

   163 /***********************************************************************/

   164 

   165 

   166 

   167 class generate_cc_il_c: public generate_cc_typedecl_c, il_default_variable_visitor_c {

   168 

   169   private:

   170     /* When compiling il code, it becomes necessary to determine the

   171      * data type of il operands. To do this, we must first find the

   172      * il operand's declaration, within the scope of the function block

   173      * or function currently being processed.

   174      * The following object does just that...

   175      * This object instance will then later be called while the

   176      * remaining il code is being handled.

   177      */

   178     search_il_operand_type_c *search_il_operand_type;

   179 

   180     /* The initial value that should be given to the IL default variable

   181      * imediately after a parenthesis is opened.

   182      * This variable is only used to pass data from the

   183      * il_expression_c visitor to the simple_instr_list_c visitor.

   184      *

   185      * e.g.:

   186      *         LD var1

   187      *         AND ( var2

   188      *         OR var3

   189      *         )

   190      *

   191      * In the above code sample, the line 'AND ( var2' constitutes

   192      * an il_expression_c, where var2 should be loaded into the

   193      * il default variable before continuing with the expression

   194      * inside the parenthesis.

   195      * Unfortunately, only the simple_instr_list_c may do the

   196      * initial laoding of the var2 bariable following the parenthesis,

   197      * so the il_expression_c visitor will have to pass 'var2' as a

   198      * parameter to the simple_instr_list_c visitor.

   199      * Ergo, the existance of the following parameter...!

   200      */

   201     symbol_c *il_default_variable_init_value;

   202 

   203     /* Operand to the IL operation currently being processed... */

   204     /* These variables are used to pass data from the

   205      * il_simple_operation_c and il_expression_c visitors

   206      * to the il operator visitors (i.e. LD_operator_c,

   207      * LDN_operator_c, ST_operator_c, STN_operator_c, ...)

   208      */

   209     symbol_c *current_operand;

   210     symbol_c *current_operand_type;

   211 

   212     /* Label to which the current IL jump operation should jump to... */

   213     /* This variable is used to pass data from the

   214      * il_jump_operation_c visitor

   215      * to the il jump operator visitors (i.e. JMP_operator_c,

   216      * JMPC_operator_c, JMPCN_operator_c, ...)

   217      */

   218     symbol_c *jump_label;

   219 

   220     /* The result of the comparison IL operations (GT, EQ, LT, ...)

   221      * is a boolean variable.

   222      * This class keeps track of the current data type stored in the

   223      * il default variable. This is usually done by keeping a reference

   224      * to the data type of the last operand. Nevertheless, in the case of

   225      * the comparison IL operators, the data type of the result (a boolean)

   226      * is not the data type of the operand. We therefore need an object

   227      * of the boolean data type to keep as a reference of the current

   228      * data type.

   229      * The following object is it...

   230      */

   231     bool_type_name_c bool_type;

   232 

   233     /* the data type of the IL default variable... */

   234     #define IL_DEFVAR_T VAR_LEADER "IL_DEFVAR_T"

   235     /* The name of the IL default variable... */

   236     #define IL_DEFVAR   VAR_LEADER "IL_DEFVAR"

   237     /* The name of the variable used to pass the result of a

   238      * parenthesised instruction list to the immediately preceding

   239      * scope ...

   240      */

   241     #define IL_DEFVAR_BACK   VAR_LEADER "IL_DEFVAR_BACK"

   242     il_default_variable_c default_variable_name;

   243     il_default_variable_c default_variable_back_name;

   244 

   245     /* Some function calls in the body of functions or function blocks

   246      * may leave some parameters to their default values, and

   247      * ignore some output parameters of the function being called.

   248      * Our conversion of ST functions to C++ does not contemplate that,

   249      * i.e. each called function must get all it's input and output

   250      * parameters set correctly.

   251      * For input parameters we merely need to call the function with

   252      * the apropriate default value, but for output parameters

   253      * we must create temporary variables to hold the output value.

   254      *

   255      * We declare all the temporary output variables at the begining of

   256      * the body of each function or function block, and use them as

   257      * in function calls later on as they become necessary...

   258      * Note that we cannot create these variables just before a function

   259      * call, as the function call itself may be integrated within an

   260      * expression, or another function call!

   261      *

   262      * The variables are declared in the exact same order in which they

   263      * will be used later on during the function calls, which allows us

   264      * to simply re-create the name that was used for the temporary variable

   265      * instead of keeping it in some list.

   266      * The names are recreated by the temp_var_name_factory, after reset()

   267      * has been called!

   268      *

   269      * This function will genertae code similar to...

   270      *

   271      *     INT __TMP_0 = 23;

   272      *     REAL __TMP_1 = 45.5;

   273      *     ...

   274      */

   275     temp_var_name_c temp_var_name_factory;

   276 

   277     /* When calling a function block, we must first find it's type,

   278      * by searching through the declarations of the variables currently

   279      * in scope.

   280      * This class does just that...

   281      * A new class is instantiated whenever we begin generating the code

   282      * for a function block type declaration, or a program declaration.

   283      * This object instance will then later be called while the

   284      * function block's or the program's body is being handled.

   285      *

   286      * Note that functions cannot contain calls to function blocks,

   287      * so we do not create an object instance when handling

   288      * a function declaration.

   289      */

   290     search_fb_instance_decl_c *search_fb_instance_decl;

   291 

   292 

   293   public:

   294     generate_cc_il_c(stage4out_c *s4o_ptr, symbol_c *scope, const char *variable_prefix = NULL)

   295     : generate_cc_typedecl_c(s4o_ptr),

   296       default_variable_name(IL_DEFVAR, NULL),

   297       default_variable_back_name(IL_DEFVAR_BACK, NULL)

   298     {

   299       search_il_operand_type  = new search_il_operand_type_c(scope);

   300       search_fb_instance_decl = new search_fb_instance_decl_c(scope);

   301       current_operand = NULL;

   302       current_operand_type = NULL;

   303       il_default_variable_init_value = NULL;

   304       this->set_variable_prefix(variable_prefix);

   305     }

   306 

   307     virtual ~generate_cc_il_c(void) {

   308       delete search_fb_instance_decl;

   309       delete search_il_operand_type;

   310     }

   311 

   312     void generate(instruction_list_c *il) {

   313       generate_cc_tempvardecl_c generate_cc_tempvardecl(&s4o);

   314       generate_cc_tempvardecl.generate(il, &temp_var_name_factory);

   315       il->accept(*this);

   316     }

   317 

   318   private:

   319     /* A helper function... */

   320     bool is_bool_type(symbol_c *type_symbol) {

   321       return (NULL != dynamic_cast<bool_type_name_c *>(type_symbol));

   322     }

   323 

   324     /* A helper function... */

   325     void *XXX_operator(symbol_c *lo, const char *op, symbol_c *ro) {

   326       if ((NULL == lo) || (NULL == ro)) ERROR;

   327       if (NULL == op) ERROR;

   328 

   329       lo->accept(*this);

   330       s4o.print(op);

   331       ro->accept(*this);

   332       return NULL;

   333     }

   334 

   335     /* A helper function... */

   336     void *XXX_CAL_operator(const char *param_name, symbol_c *fb_name) {

   337       if (NULL == fb_name) ERROR;

   338       symbolic_variable_c *sv = dynamic_cast<symbolic_variable_c *>(fb_name);

   339       if (NULL == sv) ERROR;

   340       identifier_c *id = dynamic_cast<identifier_c *>(sv->var_name);

   341       if (NULL == id) ERROR;

   342 

   343       identifier_c param(param_name);

   344 

   345       //SYM_REF4(il_param_assignment_c, il_assign_operator, il_operand, simple_instr_list, unused)

   346       il_param_assignment_c il_param_assignment(&param, &this->default_variable_name, NULL, NULL);

   347       // SYM_LIST(il_param_list_c)

   348       il_param_list_c il_param_list;

   349       il_param_list.add_element(&il_param_assignment);

   350       CAL_operator_c CAL_operator;

   351       // SYM_REF4(il_fb_call_c, il_call_operator, fb_name, il_operand_list, il_param_list)

   352       il_fb_call_c il_fb_call(&CAL_operator, id, NULL, &il_param_list);

   353 

   354       il_fb_call.accept(*this);

   355       return NULL;

   356     }

   357 

   358     /* A helper function... */

   359     void *CMP_operator(symbol_c *o, const char *operation) {

   360       if (NULL == o) ERROR;

   361       if (NULL == this->default_variable_name.current_type) ERROR;

   362 

   363       symbol_c *backup = this->default_variable_name.current_type;

   364       this->default_variable_name.current_type = &(this->bool_type);

   365       this->default_variable_name.accept(*this);

   366       this->default_variable_name.current_type = backup;

   367 

   368       s4o.print(" = (");

   369       this->default_variable_name.accept(*this);

   370       s4o.print(operation);

   371       o->accept(*this);

   372       s4o.print(")");

   373 

   374       /* the data type resulting from this operation... */

   375       this->default_variable_name.current_type = &(this->bool_type);

   376       return NULL;

   377     }

   378 

   379 

   380     /* A helper function... */

   381     void C_modifier(void) {

   382       if (NULL == this->default_variable_name.current_type) ERROR;

   383 

   384       s4o.print("if (");

   385       this->default_variable_name.accept(*this);

   386       s4o.print(") ");

   387     }

   388 

   389     /* A helper function... */

   390     void CN_modifier(void) {

   391       if (NULL == this->default_variable_name.current_type) ERROR;

   392 

   393       s4o.print("if (!");

   394       this->default_variable_name.accept(*this);

   395       s4o.print(") ");

   396     }

   397 

   398 

   399 public:

   400 void *visit(il_default_variable_c *symbol) {

   401   //s4o.print("il_default_variable_c VISITOR!!\n");

   402   symbol->var_name->accept(*this);

   403   if (NULL != symbol->current_type) {

   404     s4o.print(".");

   405     symbol->current_type->accept(*this);

   406     s4o.print("var");

   407   }

   408   return NULL;

   409 }

   410 

   411 

   412 private:

   413 /****************************************/

   414 /* B.2 - Language IL (Instruction List) */

   415 /****************************************/

   416 

   417 /***********************************/

   418 /* B 2.1 Instructions and Operands */

   419 /***********************************/

   420 

   421 /* please see the comment before the RET_operator_c visitor for details... */

   422 #define END_LABEL VAR_LEADER "end"

   423 

   424 /*| instruction_list il_instruction */

   425 void *visit(instruction_list_c *symbol) {

   426   /* Declare the backup to the default variable, that will store the result

   427    * of the IL operations executed inside a parenthesis...

   428    */

   429   s4o.print(s4o.indent_spaces);

   430   s4o.print(IL_DEFVAR_T);

   431   s4o.print(" ");

   432   this->default_variable_back_name.accept(*this);

   433   s4o.print(";\n");

   434 

   435   /* Declare the default variable, that will store the result of the IL operations... */

   436   s4o.print(s4o.indent_spaces);

   437   s4o.print(IL_DEFVAR_T);

   438   s4o.print(" ");

   439   this->default_variable_name.accept(*this);

   440   s4o.print(";\n\n");

   441 

   442   print_list(symbol, s4o.indent_spaces, ";\n" + s4o.indent_spaces, ";\n");

   443 

   444   /* write the label marking the end of the code block */

   445   /* please see the comment before the RET_operator_c visitor for details... */

   446   s4o.print("\n");

   447   s4o.print(s4o.indent_spaces);

   448   s4o.print(END_LABEL);

   449   s4o.print(":\n");

   450   s4o.indent_right();

   451   /* since every label must be followed by at least one statement, and

   452    * only the functions will introduce the return statement after this label,

   453    * function blocks written in IL would result in invalid C++ code.

   454    * To work around this we introduce the equivalent of a 'nop' operation

   455    * to humour the compiler...

   456    */

   457   s4o.print(s4o.indent_spaces);

   458   s4o.print("/* to humour the compiler, we insert a nop */\n");

   459   s4o.print(s4o.indent_spaces);

   460   this->default_variable_name.accept(*this);

   461   s4o.print(" = ");

   462   this->default_variable_name.accept(*this);

   463   s4o.print(";\n");

   464   s4o.indent_left();

   465 

   466   return NULL;

   467 }

   468 

   469 

   470 /* | label ':' [il_incomplete_instruction] eol_list */

   471 // SYM_REF2(il_instruction_c, label, il_instruction)

   472 void *visit(il_instruction_c *symbol) {

   473   if (NULL != symbol->label) {

   474     symbol->label->accept(*this);

   475     s4o.print(":\n");

   476     s4o.print(s4o.indent_spaces);

   477   }

   478   symbol->il_instruction->accept(*this);

   479   return NULL;

   480 }

   481 

   482 /* | il_simple_operator [il_operand] */

   483 //SYM_REF2(il_simple_operation_c, il_simple_operator, il_operand)

   484 void *visit(il_simple_operation_c *symbol) {

   485   this->current_operand = symbol->il_operand;

   486   if (NULL == this->current_operand) {

   487     this->current_operand_type = NULL;

   488   } else {

   489     this->current_operand_type = search_il_operand_type->get_type(this->current_operand);

   490     if (NULL == this->current_operand_type) ERROR;

   491   }

   492 

   493   symbol->il_simple_operator->accept(*this);

   494 

   495   this->current_operand = NULL;

   496   this->current_operand_type = NULL;

   497   return NULL;

   498 }

   499 

   500 

   501 /* | function_name [il_operand_list] */

   502 // SYM_REF2(il_function_call_c, function_name, il_operand_list)

   503 void *visit(il_function_call_c *symbol) {

   504   function_declaration_c *f_decl = function_symtable.find_value(symbol->function_name);

   505 

   506   if (f_decl == function_symtable.end_value())

   507     /* should never occur. The function being called MUST be in the symtable... */

   508     ERROR;

   509 

   510   /* determine the base data type returned by the function being called... */

   511   search_base_type_c search_base_type;

   512   symbol_c *return_data_type = (symbol_c *)f_decl->type_name->accept(search_base_type);

   513   symbol_c *param_data_type = default_variable_name.current_type;

   514   if (NULL == return_data_type) ERROR;

   515 

   516   default_variable_name.current_type = return_data_type;

   517   this->default_variable_name.accept(*this);

   518   default_variable_name.current_type = param_data_type;

   519   s4o.print(" = ");

   520 

   521   symbol->function_name->accept(*this);

   522   s4o.print("(");

   523 

   524   /* loop through each function parameter, find the value we should pass

   525    * to it, and then output the c equivalent...

   526    */

   527 

   528   function_param_iterator_c fp_iterator(f_decl);

   529   identifier_c *param_name;

   530   function_call_param_iterator_c function_call_param_iterator(symbol);

   531   for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

   532     if (i != 1)

   533       s4o.print(", ");

   534 

   535     symbol_c *param_type = fp_iterator.param_type();

   536     if (param_type == NULL) ERROR;

   537 

   538     function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

   539 

   540 

   541     symbol_c *param_value = NULL;

   542 

   543     /* if it is the first parameter, semantics specifies that we should

   544      * get the value off the IL default variable!

   545      */

   546    if (1 == i)

   547      param_value = &this->default_variable_name;

   548 

   549     /* Get the value from a foo(<param_name> = <param_value>) style call */

   550     /* NOTE: the following line of code is not required in this case, but it doesn't

   551      * harm to leave it in, as in the case of a non-formal syntax function call,

   552      * it will always return NULL.

   553      * We leave it in in case we later decide to merge this part of the code together

   554      * with the function calling code in generate_cc_st_c, which does require

   555      * the following line...

   556      */

   557     if (param_value == NULL)

   558       param_value = function_call_param_iterator.search(param_name);

   559 

   560     /* Get the value from a foo(<param_value>) style call */

   561     if (param_value == NULL)

   562       param_value = function_call_param_iterator.next();

   563 

   564     switch (param_direction) {

   565       case function_param_iterator_c::direction_in:

   566         if (param_value == NULL) {

   567           /* No value given for parameter, so we must use the default... */

   568           /* First check whether default value specified in function declaration...*/

   569           param_value = fp_iterator.default_value();

   570         }

   571         if (param_value == NULL) {

   572           /* If not, get the default value of this variable's type */

   573           param_value = (symbol_c *)param_type->accept(*type_initial_value_c::instance());

   574         }

   575         if (param_value == NULL) ERROR;

   576         param_value->accept(*this);

   577 	break;

   578       case function_param_iterator_c::direction_out:

   579       case function_param_iterator_c::direction_inout:

   580         if (param_value == NULL) {

   581 	  /* no parameter value given, so we pass a previously declared temporary variable. */

   582           std::string *temp_var_name = temp_var_name_factory.new_name();

   583           s4o.print(*temp_var_name);

   584           delete temp_var_name;

   585 	} else {

   586           param_value->accept(*this);

   587 	}

   588 	break;

   589       case function_param_iterator_c::direction_extref:

   590         /* TODO! */

   591         ERROR;

   592 	break;

   593     } /* switch */

   594   } /* for(...) */

   595 

   596   s4o.print(")");

   597 

   598   /* the data type returned by the function, and stored in the il default variable... */

   599   default_variable_name.current_type = return_data_type;

   600 

   601   return NULL;

   602 }

   603 

   604 

   605 /* | il_expr_operator '(' [il_operand] eol_list [simple_instr_list] ')' */

   606 //SYM_REF4(il_expression_c, il_expr_operator, il_operand, simple_instr_list, unused)

   607 void *visit(il_expression_c *symbol) {

   608   /* We will be recursevely interpreting an instruction list,

   609    * so we store a backup of the data type of the value currently stored

   610    * in the default variable, and set the current data type to NULL

   611    */

   612   symbol_c *old_current_default_variable_data_type = this->default_variable_name.current_type;

   613   this->default_variable_name.current_type = NULL;

   614 

   615  /* Pass the symbol->il_operand to the simple_instr_list visitor

   616   * using the il_default_variable_init_value parameter...

   617   * Note that the simple_instr_list_c visitor will set this parameter

   618   * to NULL as soon as it does not require it any longer,

   619   * so we don't do it here again after the

   620   *   symbol->simple_instr_list->accept(*this);

   621   * returns...

   622   */

   623   this->il_default_variable_init_value = symbol->il_operand;

   624 

   625   /* Now do the parenthesised instructions... */

   626   /* NOTE: the following code line will get the variable

   627    * this->default_variable_name.current_type updated!

   628    */

   629   symbol->simple_instr_list->accept(*this);

   630 

   631   /* Now do the operation, using the previous result! */

   632   /* NOTE: The result of the previous instruction list will be stored

   633    * in a variable named IL_DEFVAR_BACK. This is done in the visitor

   634    * to instruction_list_c objects...

   635    */

   636   this->current_operand = &(this->default_variable_back_name);

   637   this->current_operand_type = this->default_variable_back_name.current_type;

   638 

   639   this->default_variable_name.current_type = old_current_default_variable_data_type;

   640   if (NULL == this->current_operand_type) ERROR;

   641 

   642   symbol->il_expr_operator->accept(*this);

   643 

   644   this->current_operand = NULL;

   645   this->current_operand_type = NULL;

   646   this->default_variable_back_name.current_type = NULL;

   647   return NULL;

   648 }

   649 

   650 /*  il_jump_operator label */

   651 // SYM_REF2(il_jump_operation_c, il_jump_operator, label)

   652 void *visit(il_jump_operation_c *symbol) {

   653  /* Pass the symbol->label to the il_jump_operation visitor

   654   * using the jump_label parameter...

   655   */

   656   this->jump_label = symbol->label;

   657   symbol->il_jump_operator->accept(*this);

   658   this->jump_label = NULL;

   659 

   660   return NULL;

   661 }

   662 

   663 /*   il_call_operator prev_declared_fb_name

   664  * | il_call_operator prev_declared_fb_name '(' ')'

   665  * | il_call_operator prev_declared_fb_name '(' eol_list ')'

   666  * | il_call_operator prev_declared_fb_name '(' il_operand_list ')'

   667  * | il_call_operator prev_declared_fb_name '(' eol_list il_param_list ')'

   668  */

   669 // SYM_REF4(il_fb_call_c, il_call_operator, fb_name, il_operand_list, il_param_list)

   670 void *visit(il_fb_call_c *symbol) {

   671   symbol->il_call_operator->accept(*this);

   672   s4o.print("{\n");

   673   s4o.indent_right();

   674   s4o.print(s4o.indent_spaces);

   675 

   676   /* first figure out what is the name of the function block type of the function block being called... */

   677   symbol_c *function_block_type_name = this->search_fb_instance_decl->get_type_name(symbol->fb_name);

   678     /* should never occur. The function block instance MUST have been declared... */

   679   if (function_block_type_name == NULL) ERROR;

   680 

   681   /* Now find the declaration of the function block type being called... */

   682   function_block_declaration_c *fb_decl = function_block_type_symtable.find_value(function_block_type_name);

   683     /* should never occur. The function block type being called MUST be in the symtable... */

   684   if (fb_decl == function_block_type_symtable.end_value()) ERROR;

   685 

   686   /* loop through each function block parameter, find the value we should pass

   687    * to it, and then output the c equivalent...

   688    */

   689   function_param_iterator_c fp_iterator(fb_decl);

   690   identifier_c *param_name;

   691   function_call_param_iterator_c function_call_param_iterator(symbol);

   692   for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

   693     function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

   694 

   695     /* Get the value from a foo(<param_name> = <param_value>) style call */

   696     symbol_c *param_value = function_call_param_iterator.search(param_name);

   697 

   698     /* Get the value from a foo(<param_value>) style call */

   699     if (param_value == NULL)

   700       param_value = function_call_param_iterator.next();

   701 

   702     /* now output the value assignment */

   703     if (param_value != NULL)

   704       if ((param_direction == function_param_iterator_c::direction_in) ||

   705           (param_direction == function_param_iterator_c::direction_inout)) {

   706         symbol->fb_name->accept(*this);

   707         s4o.print(".");

   708         param_name->accept(*this);

   709         s4o.print(" = ");

   710         param_value->accept(*this);

   711         s4o.print(";\n" + s4o.indent_spaces);

   712       }

   713   } /* for(...) */

   714 

   715   /* now call the function... */

   716   function_block_type_name->accept(*this);

   717   s4o.print(FB_FUNCTION_SUFFIX);

   718   s4o.print("(&");

   719   symbol->fb_name->accept(*this);

   720   s4o.print(")");

   721 

   722   /* loop through each function parameter, find the variable to which

   723    * we should atribute the value of all output or inoutput parameters.

   724    */

   725   fp_iterator.reset();

   726   function_call_param_iterator.reset();

   727   for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

   728     function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

   729 

   730     /* Get the value from a foo(<param_name> = <param_value>) style call */

   731     symbol_c *param_value = function_call_param_iterator.search(param_name);

   732 

   733     /* Get the value from a foo(<param_value>) style call */

   734     if (param_value == NULL)

   735       param_value = function_call_param_iterator.next();

   736 

   737     /* now output the value assignment */

   738     if (param_value != NULL)

   739       if ((param_direction == function_param_iterator_c::direction_out) ||

   740           (param_direction == function_param_iterator_c::direction_inout)) {

   741         s4o.print(";\n"+ s4o.indent_spaces);

   742         param_value->accept(*this);

   743         s4o.print(" = ");

   744         symbol->fb_name->accept(*this);

   745         s4o.print(".");

   746         param_name->accept(*this);

   747       }

   748   } /* for(...) */

   749 

   750   s4o.print(";\n");

   751   s4o.indent_left();

   752   s4o.print(s4o.indent_spaces);

   753   s4o.print("}");

   754 

   755   return NULL;

   756 }

   757 

   758 

   759 

   760 /* | function_name '(' eol_list [il_param_list] ')' */

   761 // SYM_REF2(il_formal_funct_call_c, function_name, il_param_list)

   762 void *visit(il_formal_funct_call_c *symbol) {

   763   function_declaration_c *f_decl = function_symtable.find_value(symbol->function_name);

   764 

   765   if (f_decl == function_symtable.end_value())

   766     /* should never occur. The function being called MUST be in the symtable... */

   767     ERROR;

   768 

   769   symbol->function_name->accept(*this);

   770   s4o.print("(");

   771 

   772   /* loop through each function parameter, find the value we should pass

   773    * to it, and then output the c equivalent...

   774    */

   775 

   776   function_param_iterator_c fp_iterator(f_decl);

   777   identifier_c *param_name;

   778   function_call_param_iterator_c function_call_param_iterator(symbol);

   779   for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

   780     if (i != 1)

   781       s4o.print(", ");

   782 

   783     symbol_c *param_type = fp_iterator.param_type();

   784     if (param_type == NULL) ERROR;

   785 

   786     function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

   787 

   788 

   789     symbol_c *param_value = NULL;

   790 

   791     /* Get the value from a foo(<param_name> = <param_value>) style call */

   792     if (param_value == NULL)

   793       param_value = function_call_param_iterator.search(param_name);

   794 

   795     /* Get the value from a foo(<param_value>) style call */

   796     /* NOTE: the following line of code is not required in this case, but it doesn't

   797      * harm to leave it in, as in the case of a formal syntax function call,

   798      * it will always return NULL.

   799      * We leave it in in case we later decide to merge this part of the code together

   800      * with the function calling code in generate_cc_st_c, which does require

   801      * the following line...

   802      */

   803     if (param_value == NULL)

   804       param_value = function_call_param_iterator.next();

   805 

   806     switch (param_direction) {

   807       case function_param_iterator_c::direction_in:

   808         if (param_value == NULL) {

   809           /* No value given for parameter, so we must use the default... */

   810           /* First check whether default value specified in function declaration...*/

   811           param_value = fp_iterator.default_value();

   812         }

   813         if (param_value == NULL) {

   814           /* If not, get the default value of this variable's type */

   815           param_value = (symbol_c *)param_type->accept(*type_initial_value_c::instance());

   816         }

   817         if (param_value == NULL) ERROR;

   818         param_value->accept(*this);

   819 	break;

   820       case function_param_iterator_c::direction_out:

   821       case function_param_iterator_c::direction_inout:

   822         if (param_value == NULL) {

   823 	  /* no parameter value given, so we pass a previously declared temporary variable. */

   824           std::string *temp_var_name = temp_var_name_factory.new_name();

   825           s4o.print(*temp_var_name);

   826           delete temp_var_name;

   827 	} else {

   828           param_value->accept(*this);

   829 	}

   830 	break;

   831       case function_param_iterator_c::direction_extref:

   832         /* TODO! */

   833         ERROR;

   834 	break;

   835     } /* switch */

   836   } /* for(...) */

   837 

   838   // symbol->parameter_assignment->accept(*this);

   839   s4o.print(")");

   840   return NULL;

   841 }

   842 

   843 

   844 /* | il_operand_list ',' il_operand */

   845 // SYM_LIST(il_operand_list_c)

   846 void *visit(il_operand_list_c *symbol) {ERROR; return NULL;} // should never get called!

   847 

   848 

   849 /* | simple_instr_list il_simple_instruction */

   850 // SYM_LIST(simple_instr_list_c)

   851 void *visit(simple_instr_list_c *symbol) {

   852   /* A simple_instr_list_c is used to store a list of il operations

   853    * being done within parenthesis...

   854    *

   855    * e.g.:

   856    *         LD var1

   857    *         AND ( var2

   858    *         OR var3

   859    *         OR var4

   860    *         )

   861    *

   862    * This will be converted to C++ by defining a new scope

   863    * with a new il default variable, and executing the il operands

   864    * within this new scope.

   865    * At the end of the scope the result, i.e. the value currently stored

   866    * in the il default variable is copied to the variable used to take this

   867    * value to the outside scope...

   868    *

   869    * The above example will result in the following C++ code:

   870    * {__IL_DEFVAR_T __IL_DEFVAR_BACK;

   871    *  __IL_DEFVAR_T __IL_DEFVAR;

   872    *

   873    *  __IL_DEFVAR.INTvar = var1;

   874    *  {

   875    *    __IL_DEFVAR_T __IL_DEFVAR;

   876    *

   877    *    __IL_DEFVAR.INTvar = var2;

   878    *    __IL_DEFVAR.INTvar |= var3;

   879    *    __IL_DEFVAR.INTvar |= var4;

   880    *

   881    *    __IL_DEFVAR_BACK = __IL_DEFVAR;

   882    *  }

   883    *  __IL_DEFVAR.INTvar &= __IL_DEFVAR_BACK.INTvar;

   884    *

   885    * }

   886    *

   887    *  The intial value of the il default variable (in the above

   888    * example 'var2') is passed to this simple_instr_list_c visitor

   889    * using the il_default_variable_init_value parameter.

   890    * Since it is possible to have parenthesis inside other parenthesis

   891    * recursively, we reset the il_default_variable_init_value to NULL

   892    * as soon as we no longer require it, as it may be used once again

   893    * in the line

   894    *  print_list(symbol, s4o.indent_spaces, ";\n" + s4o.indent_spaces, ";\n");

   895    *

   896    */

   897 

   898   /* Declare the default variable, that will store the result of the IL operations... */

   899   s4o.print("{\n");

   900   s4o.indent_right();

   901 

   902   s4o.print(s4o.indent_spaces);

   903   s4o.print(IL_DEFVAR_T);

   904   s4o.print(" ");

   905   this->default_variable_name.accept(*this);

   906   s4o.print(";\n\n");

   907 

   908   /* Check whether we should initiliase the il default variable... */

   909   if (NULL != this->il_default_variable_init_value) {

   910     /* Yes, we must... */

   911     /* We will do it by instatiating a LD operator, and having this

   912      * same generate_cc_il_c class visiting it!

   913      */

   914     LD_operator_c ld_oper;

   915     il_simple_operation_c il_simple_oper(&ld_oper, this->il_default_variable_init_value);

   916 

   917     s4o.print(s4o.indent_spaces);

   918     il_simple_oper.accept(*this);

   919     s4o.print(";\n");

   920   }

   921 

   922   /* this parameter no longer required... */

   923   this->il_default_variable_init_value = NULL;

   924 

   925   print_list(symbol, s4o.indent_spaces, ";\n" + s4o.indent_spaces, ";\n");

   926 

   927   /* copy the result in the default variable to the variable

   928    * used to pass the data out to the scope enclosing

   929    * the current scope!

   930    *

   931    * We also need to update the data type currently stored within

   932    * the variable used to pass the data to the outside scope...

   933    */

   934   this->default_variable_back_name.current_type = this->default_variable_name.current_type;

   935   s4o.print("\n");

   936   s4o.print(s4o.indent_spaces);

   937   this->default_variable_back_name.accept(*this);

   938   s4o.print(" = ");

   939   this->default_variable_name.accept(*this);

   940   s4o.print(";\n");

   941 

   942   s4o.indent_left();

   943   s4o.print(s4o.indent_spaces);

   944   s4o.print("}\n");

   945   s4o.print(s4o.indent_spaces);

   946   return NULL;

   947 }

   948 

   949 /* | il_initial_param_list il_param_instruction */

   950 // SYM_LIST(il_param_list_c)

   951 void *visit(il_param_list_c *symbol) {ERROR; return NULL;} // should never get called!

   952 

   953 /*  il_assign_operator il_operand

   954  * | il_assign_operator '(' eol_list simple_instr_list ')'

   955  */

   956 // SYM_REF4(il_param_assignment_c, il_assign_operator, il_operand, simple_instr_list, unused)

   957 void *visit(il_param_assignment_c *symbol) {ERROR; return NULL;} // should never get called!

   958 

   959 /*  il_assign_out_operator variable */

   960 // SYM_REF2(il_param_out_assignment_c, il_assign_out_operator, variable);

   961 void *visit(il_param_out_assignment_c *symbol) {ERROR; return NULL;} // should never get called!

   962 

   963 /*******************/

   964 /* B 2.2 Operators */

   965 /*******************/

   966 

   967 void *visit(LD_operator_c *symbol)	{

   968   /* the data type resulting from this operation... */

   969   this->default_variable_name.current_type = this->current_operand_type;

   970   XXX_operator(&(this->default_variable_name), " = ", this->current_operand);

   971   return NULL;

   972 }

   973 

   974 void *visit(LDN_operator_c *symbol)	{

   975   /* the data type resulting from this operation... */

   976   this->default_variable_name.current_type = this->current_operand_type;

   977   XXX_operator(&(this->default_variable_name),

   978                is_bool_type(this->current_operand_type)?" = !":" = ~",

   979                this->current_operand);

   980   return NULL;

   981 }

   982 

   983 void *visit(ST_operator_c *symbol)	{

   984   XXX_operator(this->current_operand, " = ",&(this->default_variable_name));

   985   /* the data type resulting from this operation is unchamged. */

   986   return NULL;

   987 }

   988 

   989 void *visit(STN_operator_c *symbol)	{

   990   XXX_operator(this->current_operand,

   991                is_bool_type(this->current_operand_type)?" = !":" = ~",

   992                &(this->default_variable_name));

   993   /* the data type resulting from this operation is unchamged. */

   994   return NULL;

   995 }

   996 

   997 void *visit(NOT_operator_c *symbol)	{

   998   if ((NULL != this->current_operand) || (NULL != this->current_operand_type)) ERROR;

   999   XXX_operator(&(this->default_variable_name),

  1000                is_bool_type(this->default_variable_name.current_type)?" = !":" = ~",

  1001                &(this->default_variable_name));

  1002   /* the data type resulting from this operation is unchanged. */

  1003   return NULL;

  1004 }

  1005 

  1006 void *visit(S_operator_c *symbol)	{

  1007   if ((NULL == this->current_operand) || (NULL == this->current_operand_type)) ERROR;

  1008 

  1009   C_modifier();

  1010   this->current_operand->accept(*this);

  1011   s4o.print(is_bool_type(this->current_operand_type)?" = true":" = 1");

  1012   /* the data type resulting from this operation is unchanged! */

  1013   return NULL;

  1014 }

  1015 

  1016 void *visit(R_operator_c *symbol)	{

  1017   if ((NULL == this->current_operand) || (NULL == this->current_operand_type)) ERROR;

  1018 

  1019   C_modifier();

  1020   this->current_operand->accept(*this);

  1021   s4o.print(is_bool_type(this->current_operand_type)?" = false":" = 0");

  1022   /* the data type resulting from this operation is unchanged! */

  1023   return NULL;

  1024 }

  1025 

  1026 void *visit(S1_operator_c *symbol)	{return XXX_CAL_operator("S1", this->current_operand);}

  1027 void *visit(R1_operator_c *symbol)	{return XXX_CAL_operator("R1", this->current_operand);}

  1028 void *visit(CLK_operator_c *symbol)	{return XXX_CAL_operator("CLK", this->current_operand);}

  1029 void *visit(CU_operator_c *symbol)	{return XXX_CAL_operator("CU", this->current_operand);}

  1030 void *visit(CD_operator_c *symbol)	{return XXX_CAL_operator("CD", this->current_operand);}

  1031 void *visit(PV_operator_c *symbol)	{return XXX_CAL_operator("PV", this->current_operand);}

  1032 void *visit(IN_operator_c *symbol)	{return XXX_CAL_operator("IN", this->current_operand);}

  1033 void *visit(PT_operator_c *symbol)	{return XXX_CAL_operator("PT", this->current_operand);}

  1034 

  1035 void *visit(AND_operator_c *symbol)	{

  1036   XXX_operator(&(this->default_variable_name), " &= ", this->current_operand);

  1037   /* the data type resulting from this operation... */

  1038   this->default_variable_name.current_type = this->current_operand_type;

  1039   return NULL;

  1040 }

  1041 

  1042 void *visit(OR_operator_c *symbol)	{

  1043   XXX_operator(&(this->default_variable_name), " |= ", this->current_operand);

  1044   /* the data type resulting from this operation... */

  1045   this->default_variable_name.current_type = this->current_operand_type;

  1046   return NULL;

  1047 }

  1048 

  1049 void *visit(XOR_operator_c *symbol)	{

  1050   // '^' is a bit by bit exclusive OR !! Also seems to work with boolean types!

  1051   XXX_operator(&(this->default_variable_name), " ^= ", this->current_operand);

  1052   /* the data type resulting from this operation... */

  1053   this->default_variable_name.current_type = this->current_operand_type;

  1054   return NULL;

  1055 }

  1056 

  1057 void *visit(ANDN_operator_c *symbol)	{

  1058   XXX_operator(&(this->default_variable_name),

  1059                is_bool_type(this->current_operand_type)?" &= !":" &= ~",

  1060                this->current_operand);

  1061   /* the data type resulting from this operation... */

  1062   this->default_variable_name.current_type = this->current_operand_type;

  1063   return NULL;

  1064 }

  1065 

  1066 void *visit(ORN_operator_c *symbol)	{

  1067   XXX_operator(&(this->default_variable_name),

  1068                is_bool_type(this->current_operand_type)?" |= !":" |= ~",

  1069                this->current_operand);

  1070   /* the data type resulting from this operation... */

  1071   this->default_variable_name.current_type = this->current_operand_type;

  1072   return NULL;

  1073 }

  1074 

  1075 void *visit(XORN_operator_c *symbol)	{

  1076   XXX_operator(&(this->default_variable_name),

  1077                // bit by bit exclusive OR !! Also seems to work with boolean types!

  1078                is_bool_type(this->current_operand_type)?" ^= !":" ^= ~",

  1079                this->current_operand);

  1080   /* the data type resulting from this operation... */

  1081   this->default_variable_name.current_type = this->current_operand_type;

  1082   return NULL;

  1083 }

  1084 

  1085 void *visit(ADD_operator_c *symbol)	{

  1086   XXX_operator(&(this->default_variable_name), " += ", this->current_operand);

  1087   /* the data type resulting from this operation... */

  1088   this->default_variable_name.current_type = this->current_operand_type;

  1089   return NULL;

  1090 }

  1091 

  1092 void *visit(SUB_operator_c *symbol)	{

  1093   XXX_operator(&(this->default_variable_name), " -= ", this->current_operand);

  1094   /* the data type resulting from this operation... */

  1095   this->default_variable_name.current_type = this->current_operand_type;

  1096   return NULL;

  1097 }

  1098 

  1099 void *visit(MUL_operator_c *symbol)	{

  1100   XXX_operator(&(this->default_variable_name), " *= ", this->current_operand);

  1101   /* the data type resulting from this operation... */

  1102   this->default_variable_name.current_type = this->current_operand_type;

  1103   return NULL;

  1104 }

  1105 

  1106 void *visit(DIV_operator_c *symbol)	{

  1107   XXX_operator(&(this->default_variable_name), " /= ", this->current_operand);

  1108   /* the data type resulting from this operation... */

  1109   this->default_variable_name.current_type = this->current_operand_type;

  1110   return NULL;

  1111 }

  1112 

  1113 void *visit(MOD_operator_c *symbol)	{

  1114   XXX_operator(&(this->default_variable_name), " %= ", this->current_operand);

  1115   /* the data type resulting from this operation... */

  1116   this->default_variable_name.current_type = this->current_operand_type;

  1117   return NULL;

  1118 }

  1119 

  1120 void *visit(GT_operator_c *symbol)	{

  1121   return CMP_operator(this->current_operand, " > ");

  1122 }

  1123 

  1124 void *visit(GE_operator_c *symbol)	{

  1125   return CMP_operator(this->current_operand, " >= ");

  1126 }

  1127 

  1128 void *visit(EQ_operator_c *symbol)	{

  1129   return CMP_operator(this->current_operand, " == ");

  1130 }

  1131 

  1132 void *visit(LT_operator_c *symbol)	{

  1133   return CMP_operator(this->current_operand, " < ");

  1134 }

  1135 

  1136 void *visit(LE_operator_c *symbol)	{