mario@181: /*
mario@181:  * (c) 2003 Mario de Sousa
mario@181:  *
mario@181:  * Offered to the public under the terms of the GNU General Public License
mario@181:  * as published by the Free Software Foundation; either version 2 of the
mario@181:  * License, or (at your option) any later version.
mario@181:  *
mario@181:  * This program is distributed in the hope that it will be useful, but
mario@181:  * WITHOUT ANY WARRANTY; without even the implied warranty of
mario@181:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
mario@181:  * Public License for more details.
mario@181:  *
mario@181:  * This code is made available on the understanding that it will not be
mario@181:  * used in safety-critical situations without a full and competent review.
mario@181:  */
mario@181: 
mario@181: /*
mario@181:  * An IEC 61131-3 IL and ST compiler.
mario@181:  *
mario@181:  * Based on the
mario@181:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
mario@181:  *
mario@181:  */
mario@181: 
mario@181: /* Determine the data type of a variable.
mario@181:  * The variable may be a simple variable, a function block instance, a
mario@181:  * struture element within a data structured type (a struct or a fb), or
mario@181:  * an array element.
mario@181:  * A mixture of array element of a structure element of a structure element
mario@181:  * of a .... is also suported!
mario@181:  *
mario@181:  * A reference to the relevant base type __definition__ is returned.
mario@181:  * This means that if we find that the variable is of type MY_INT,
mario@181:  * which was previously declared to be
mario@181:  * TYPE MY_INT: INT := 9;
mario@181:  * this class wil return INT, and __not__ MY_INT !!
mario@181:  *
mario@181:  *
mario@181:  *  example:
mario@181:  *    window.points[1].coordinate.x
mario@181:  *    window.points[1].colour
mario@181:  *    etc... ARE ALLOWED!
mario@181:  *
mario@181:  * This class must be passed the scope within which the
mario@181:  * variable was declared, and the variable name...
mario@181:  */
mario@181: 
mario@181: 
ccb@202: /*
ccb@202:  * TODO: this code has a memory leak...
ccb@202:  *       We call 'new' in several locations, but bever get to 'delete' the object instances...
ccb@202:  */
mario@181: #include "absyntax_utils.hh"
mario@181: 
mario@181: 
mario@181: search_varfb_instance_type_c::search_varfb_instance_type_c(symbol_c *search_scope): search_var_instance_decl(search_scope) {
mario@181:   this->decompose_var_instance_name = NULL;
mario@181:   this->current_structelement_name = NULL;
mario@181:   this->search_base_type = false;
mario@181: }
mario@181: 
mario@181: symbol_c *search_varfb_instance_type_c::get_type(symbol_c *variable_name, bool base_type) {
mario@181:   this->current_structelement_name = NULL;
mario@181:   this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
mario@181:   this->search_base_type = base_type;
mario@181:   if (NULL == decompose_var_instance_name) ERROR;
mario@181: 
mario@181:   /* find the part of the variable name that will appear in the
mario@181:    * variable declaration, for e.g., in window.point.x, this would be
mario@181:    * window!
mario@181:    */
mario@181:   symbol_c *var_name_part = decompose_var_instance_name->next_part();
mario@181:   if (NULL == var_name_part) ERROR;
ccb@202: 
mario@181:   /* Now we try to find the variable instance declaration, to determine its type... */
mario@181:   symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
mario@181:   if (NULL == var_decl) {
mario@181:     /* variable instance declaration not found! */
mario@181:       ERROR;
mario@181:   }
mario@181: 
mario@181:   /* if it is a struct or function block, we must search the type
mario@181:    * of the struct or function block member.
mario@181:    * This is done by this class visiting the var_decl.
mario@181:    * This class, while visiting, will recursively call
mario@181:    * decompose_var_instance_name->get_next() when and if required...
mario@181:    */
mario@181:   symbol_c *res = (symbol_c *)var_decl->accept(*this);
mario@181:   if (NULL == res) ERROR;
mario@181: 
mario@181:   /* make sure that we have decomposed all strcuture elements of the variable name */
mario@181:   symbol_c *var_name = decompose_var_instance_name->next_part();
mario@181:   if (NULL != var_name) ERROR;
mario@181: 
mario@181:   return res;
mario@181: }
mario@181: 
mario@181: unsigned int search_varfb_instance_type_c::get_vartype(symbol_c *variable_name) {
mario@181:   this->current_structelement_name = NULL;
mario@181:   this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
mario@181:   if (NULL == decompose_var_instance_name) ERROR;
mario@181: 
mario@181:   /* find the part of the variable name that will appear in the
mario@181:    * variable declaration, for e.g., in window.point.x, this would be
mario@181:    * window!
mario@181:    */
mario@181:   symbol_c *var_name_part = decompose_var_instance_name->next_part();
mario@181:   if (NULL == var_name_part) ERROR;
mario@181: 
mario@181:   /* Now we try to find the variable instance declaration, to determine its type... */
mario@181:   symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
mario@181:   if (NULL == var_decl) {
mario@181:     /* variable instance declaration not found! */
mario@181:     return 0;
mario@181:   }
mario@181: 
mario@181:   /* if it is a struct or function block, we must search the type
mario@181:    * of the struct or function block member.
mario@181:    * This is done by this class visiting the var_decl.
mario@181:    * This class, while visiting, will recursively call
mario@181:    * decompose_var_instance_name->get_next() when and if required...
mario@181:    */
mario@181:   unsigned int res = search_var_instance_decl.get_vartype();
mario@181:   
mario@181:   /* make sure that we have decomposed all strcuture elements of the variable name */
mario@181:   symbol_c *var_name = decompose_var_instance_name->next_part();
mario@181:   if (NULL != var_name) ERROR;
mario@181: 
mario@181:   return res;
mario@181: }
mario@181: 
mario@181: /* a helper function... */
mario@181: void *search_varfb_instance_type_c::visit_list(list_c *list)	{
mario@181:   if (NULL == current_structelement_name) ERROR;
mario@181: 
mario@181:   for(int i = 0; i < list->n; i++) {
mario@181:     void *res = list->elements[i]->accept(*this);
mario@181:     if (res != NULL)
mario@181:       return res;
mario@181:   }
mario@181:   /* not found! */
mario@181:   return NULL;
mario@181: }
mario@181: 
mario@181: /* a helper function... */
mario@181: void *search_varfb_instance_type_c::base_type(symbol_c *symbol)	{
mario@181:     search_base_type_c search_base_type;
mario@181:     return symbol->accept(search_base_type);
mario@181: }
mario@181: 
mario@181: /* We override the base class' visitor to identifier_c.
mario@181:  * This is so because the base class does not consider a function block
mario@181:  * to be a type, unlike this class that allows a variable instance
mario@181:  * of a function block type...
mario@181:  */
mario@181: void *search_varfb_instance_type_c::visit(identifier_c *type_name) {
mario@181:   /* look up the type declaration... */
mario@181:   symbol_c *fb_decl = function_block_type_symtable.find_value(type_name);
mario@181:   if (fb_decl != function_block_type_symtable.end_value())
mario@181:     /* Type declaration found!! */
mario@181:     return fb_decl->accept(*this);
mario@181: 
mario@181:   /* No. It is not a function block, so we let
mario@181:    * the base class take care of it...
mario@181:    */
mario@181:   if (this->search_base_type)
mario@181:     return search_base_type_c::visit(type_name);
mario@181:   else
mario@181:     return type_name;
mario@181: }
mario@181: 
mario@181: /********************************/
mario@181: /* B 1.3.3 - Derived data types */
mario@181: /********************************/
mario@181: 
mario@181: /*  identifier ':' array_spec_init */
mario@181: void *search_varfb_instance_type_c::visit(array_type_declaration_c *symbol) {
mario@181:   return symbol->array_spec_init->accept(*this);
mario@181: }
mario@181:     
mario@181: /* array_specification [ASSIGN array_initialization} */
mario@181: /* array_initialization may be NULL ! */
mario@181: void *search_varfb_instance_type_c::visit(array_spec_init_c *symbol) {
mario@181:   symbol_c *var_name = decompose_var_instance_name->next_part();
mario@181:   if (NULL != var_name)
mario@181:     current_structelement_name = var_name;
mario@181:   return symbol->array_specification->accept(*this);
mario@181: }
mario@181:     
mario@181: /* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */
mario@181: void *search_varfb_instance_type_c::visit(array_specification_c *symbol) {
mario@181:   symbol_c *var_name = decompose_var_instance_name->next_part();
mario@181:   if (NULL != var_name)
mario@181:     current_structelement_name = var_name;
mario@181:   return symbol->non_generic_type_name->accept(*this);
mario@181: }
mario@181: 
mario@181: /*  structure_type_name ':' structure_specification */
mario@181: void *search_varfb_instance_type_c::visit(structure_type_declaration_c *symbol) {
mario@181:   return symbol->structure_specification->accept(*this);
mario@181:   /* NOTE: structure_specification will point to either a
mario@181:    *       initialized_structure_c
mario@181:    *       OR A
mario@181:    *       structure_element_declaration_list_c
mario@181:    */
mario@181: }
mario@181: 
mario@181: /* structure_type_name ASSIGN structure_initialization */
mario@181: /* structure_initialization may be NULL ! */
mario@181: // SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)
mario@181: void *search_varfb_instance_type_c::visit(initialized_structure_c *symbol)	{
mario@181:   /* make sure that we have decomposed all strcuture elements of the variable name */
mario@181:   symbol_c *var_name = decompose_var_instance_name->next_part();
mario@181:   if (NULL == var_name) {
mario@181:     /* this is it... !
mario@181:      * No need to look any further...
mario@181:      */
mario@181:     /* NOTE: we could simply do a
mario@181:     *   return (void *)symbol;
mario@181:     *       nevertheless, note that this search_varfb_instance_type_c
mario@181:     *       class inherits from the search_base_type_c class,
mario@181:     *       which means that it will usually return the base type,
mario@181:     *       and not the derived type (*). If we are to be consistent,
mario@181:     *       we should guarantee that we always return the base type.
mario@181:     *       To do this we could use
mario@181:     *   return (void *)symbol->accept(*this);
mario@181:     *       since this class inherits from the search_base_type_c.
mario@181:     *       However, in this case we don't want it to follow
mario@181:     *       the structs as this search_varfb_instance_type_c does.
mario@181:     *       We therefore have to create a new search_base_type_c
mario@181:     *       instance to search through this type without going
mario@181:     *       through the structs...
mario@181:     */
mario@181:       return base_type(symbol->structure_type_name);
mario@181:   }
mario@181: 
mario@181:   /* now search the structure declaration */
mario@181:   current_structelement_name = var_name;
mario@181:   /* recursively find out the data type of var_name... */
mario@181:   return symbol->structure_type_name->accept(*this);
mario@181: }
mario@181: 
mario@181: /* helper symbol for structure_declaration */
mario@181: /* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */
mario@181: /* structure_element_declaration_list structure_element_declaration ';' */
mario@181: void *search_varfb_instance_type_c::visit(structure_element_declaration_list_c *symbol)	{
mario@181:   return visit_list(symbol);
mario@181: }
mario@181: 
mario@181: /*  structure_element_name ':' spec_init */
mario@181: void *search_varfb_instance_type_c::visit(structure_element_declaration_c *symbol) {
mario@181:   if (NULL == current_structelement_name) ERROR;
mario@181: 
mario@181:   if (compare_identifiers(symbol->structure_element_name, current_structelement_name) == 0)
mario@181:     return symbol->spec_init->accept(*this);
mario@181: 
mario@181:   return NULL;
mario@181: }
mario@181: 
mario@181: /* helper symbol for structure_initialization */
mario@181: /* structure_initialization: '(' structure_element_initialization_list ')' */
mario@181: /* structure_element_initialization_list ',' structure_element_initialization */
mario@181: void *search_varfb_instance_type_c::visit(structure_element_initialization_list_c *symbol) {ERROR; return NULL;} /* should never get called... */
mario@181: /*  structure_element_name ASSIGN value */
mario@181: void *search_varfb_instance_type_c::visit(structure_element_initialization_c *symbol) {ERROR; return NULL;} /* should never get called... */
mario@181: 
mario@181: 
mario@181: 
mario@181: /**************************************/
mario@181: /* B.1.5 - Program organization units */
mario@181: /**************************************/
mario@181: /*****************************/
mario@181: /* B 1.5.2 - Function Blocks */
mario@181: /*****************************/
mario@181: /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */
mario@181: // SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)
mario@181: void *search_varfb_instance_type_c::visit(function_block_declaration_c *symbol) {
mario@181:   /* make sure that we have decomposed all strcuture elements of the variable name */
mario@181: 
mario@181:   symbol_c *var_name = decompose_var_instance_name->next_part();
mario@181:   if (NULL == var_name) {
mario@181:     /* this is it... !
mario@181:      * No need to look any further...
mario@181:      * Note also that, unlike for the struct types, a function block may
mario@181:      * not be defined based on another (i.e. no inheritance is allowed),
mario@181:      * so this function block is already the most base type.
mario@181:      * We simply return it.
mario@181:      */
mario@181:     return (void *)symbol;
mario@181:    }
mario@181: 
mario@181:    /* now search the function block declaration for the variable... */
mario@181:    search_var_instance_decl_c search_decl(symbol);
mario@181:    symbol_c *var_decl = search_decl.get_decl(var_name);
mario@181:    if (NULL == var_decl) {
mario@181:      /* variable instance declaration not found! */
mario@181:      return NULL;
mario@181:    }
mario@181: 
mario@181:    /* We have found the declaration.
mario@181:     * Should we look any further?
mario@181:     */
mario@181:    var_name = decompose_var_instance_name->next_part();
mario@181:    if (NULL == var_name) {
mario@181:      /* this is it... ! */
mario@181:      return base_type(var_decl);
mario@181:    }
mario@181: 
mario@181:   current_structelement_name = var_name;
mario@181:   /* recursively find out the data type of var_name... */
mario@181:   return symbol->var_declarations->accept(*this);
mario@181: }