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/*

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 *  matiec - a compiler for the programming languages defined in IEC 61131-3

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 *

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 *  Copyright (C) 2009-2012  Mario de Sousa (msousa@fe.up.pt)

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 *  Copyright (C) 2012       Manuele Conti (manuele.conti@sirius-es.it)

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 *  Copyright (C) 2012       Matteo Facchinetti (matteo.facchinetti@sirius-es.it)

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 *

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 *  This program is free software: you can redistribute it and/or modify

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 *  it under the terms of the GNU General Public License as published by

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 *  the Free Software Foundation, either version 3 of the License, or

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 *  (at your option) any later version.

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 *

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

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

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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *  GNU General Public License for more details.

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 *

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 *  You should have received a copy of the GNU General Public License

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 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.

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 *

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 *

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

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

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 */

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/*

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 * An IEC 61131-3 compiler.

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 *

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 * Based on the

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

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 *

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 */

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/* TODO - things yet not checked by this data type checker...

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 *

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 * - check variable declarations

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 * - check data type declarations

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 * - check inside configurations (variable declarations)

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 * - check SFC code

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 * - must fix S and R IL functions (includes potientialy fixing stage4 code!) 

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 */

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/* NOTE: The algorithm implemented here assumes that flow control analysis has already been completed!

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 *       BEFORE running this visitor, be sure to CALL the flow_control_analysis_c visitor!

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 */

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    49

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/*

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 *  Fill the candidate datatype list for all symbols that may legally 'have' a data type (e.g. variables, literals, function calls, expressions, etc.)

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 * 

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 *  The candidate datatype list will be filled with a list of all the data types that expression may legally take.

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 *  For example, the very simple literal '0' (as in foo := 0), may represent a:

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 *    BOOL, BYTE, WORD, DWORD, LWORD, USINT, SINT, UINT, INT, UDINT, DINT, ULINT, LINT (as well as the SAFE versions of these data tyes too!)

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 */

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#include "fill_candidate_datatypes.hh"

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#include "datatype_functions.hh"

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#include <typeinfo>

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#include <list>

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#include <string>

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#include <string.h>

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#include <strings.h>

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/* set to 1 to see debug info during execution */

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static int debug = 0;

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fill_candidate_datatypes_c::fill_candidate_datatypes_c(symbol_c *ignore) {

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}

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fill_candidate_datatypes_c::~fill_candidate_datatypes_c(void) {

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}

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symbol_c *fill_candidate_datatypes_c::widening_conversion(symbol_c *left_type, symbol_c *right_type, const struct widen_entry widen_table[]) {

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	int k;

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	/* find a widening table entry compatible */

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	for (k = 0; NULL != widen_table[k].left;  k++)

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		if ((typeid(*left_type) == typeid(*widen_table[k].left)) && (typeid(*right_type) == typeid(*widen_table[k].right)))

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                      return widen_table[k].result;

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	return NULL;

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}

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    89

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/* add a data type to a candidate data type list, while guaranteeing no duplicate entries! */

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/* Returns true if it really did add the datatype to the list, or false if it was already present in the list! */

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bool fill_candidate_datatypes_c::add_datatype_to_candidate_list(symbol_c *symbol, symbol_c *datatype) {

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  /* If it is an invalid data type, do not insert!

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   * NOTE: it reduces overall code size to do this test here, instead of doing every time before calling the add_datatype_to_candidate_list() function. 

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   */

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  if (!is_type_valid(datatype)) /* checks for NULL and invalid_type_name_c */

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    return false;

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  if (search_in_candidate_datatype_list(datatype, symbol->candidate_datatypes) >= 0) 

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    /* already in the list, Just return! */

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    return false;

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  /* not yet in the candidate data type list, so we insert it now! */

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  symbol->candidate_datatypes.push_back(datatype);

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  return true;

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}

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bool fill_candidate_datatypes_c::add_2datatypes_to_candidate_list(symbol_c *symbol, symbol_c *datatype1, symbol_c *datatype2) {

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  add_datatype_to_candidate_list(symbol, datatype1);

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  add_datatype_to_candidate_list(symbol, datatype2);

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  return true;

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}

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/* returns true if compatible function/FB invocation, otherwise returns false */

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/* Assumes that the candidate_datatype lists of all the parameters being passed haved already been filled in */

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/*

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 * All parameters being passed to the called function MUST be in the parameter list to which f_call points to!

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 * This means that, for non formal function calls in IL, de current (default value) must be artificially added to the

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 * beginning of the parameter list BEFORE calling handle_function_call().

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 */

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bool fill_candidate_datatypes_c::match_nonformal_call(symbol_c *f_call, symbol_c *f_decl) {

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	symbol_c *call_param_value,  *param_datatype;

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	identifier_c *param_name;

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	function_param_iterator_c       fp_iterator(f_decl);

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	function_call_param_iterator_c fcp_iterator(f_call);

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	int extensible_parameter_highest_index = -1;

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	unsigned int i;

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	/* Iterating through the non-formal parameters of the function call */

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	while((call_param_value = fcp_iterator.next_nf()) != NULL) {

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		/* Iterate to the next parameter of the function being called.

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		 * Get the name of that parameter, and ignore if EN or ENO.

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		 */

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		do {

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			param_name = fp_iterator.next();

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			/* If there is no other parameter declared, then we are passing too many parameters... */

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			if(param_name == NULL) return false;

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		} while ((strcmp(param_name->value, "EN") == 0) || (strcmp(param_name->value, "ENO") == 0));

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		/* TODO: verify if it is lvalue when INOUT or OUTPUT parameters! */

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		/* Get the parameter type */

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		param_datatype = base_type(fp_iterator.param_type());

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		/* check whether one of the candidate_data_types of the value being passed is the same as the param_type */

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		if (search_in_candidate_datatype_list(param_datatype, call_param_value->candidate_datatypes) < 0)

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			return false; /* return false if param_type not in the list! */

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	}

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	/* call is compatible! */

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	return true;

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}

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/* returns true if compatible function/FB invocation, otherwise returns false */

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/* Assumes that the candidate_datatype lists of all the parameters being passed haved already been filled in */

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bool fill_candidate_datatypes_c::match_formal_call(symbol_c *f_call, symbol_c *f_decl, symbol_c **first_param_datatype) {

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	symbol_c *call_param_value, *call_param_name, *param_datatype;

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	symbol_c *verify_duplicate_param;

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	identifier_c *param_name;

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	function_param_iterator_c       fp_iterator(f_decl);

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	function_call_param_iterator_c fcp_iterator(f_call);

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	int extensible_parameter_highest_index = -1;

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	identifier_c *extensible_parameter_name;

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	unsigned int i;

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	bool is_first_param = true;

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	/* Iterating through the formal parameters of the function call */

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	while((call_param_name = fcp_iterator.next_f()) != NULL) {

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		/* Obtaining the value being passed in the function call */

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		call_param_value = fcp_iterator.get_current_value();

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		/* the following should never occur. If it does, then we have a bug in our code... */

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		if (NULL == call_param_value) ERROR;

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		/* Obtaining the assignment direction:  := (assign_in) or => (assign_out) */

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		function_call_param_iterator_c::assign_direction_t call_param_dir = fcp_iterator.get_assign_direction();

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		/* Checking if there are duplicated parameter values */

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		verify_duplicate_param = fcp_iterator.search_f(call_param_name);

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		if(verify_duplicate_param != call_param_value)

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			return false;

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		/* Obtaining the type of the value being passed in the function call */

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		std::vector <symbol_c *>&call_param_types = call_param_value->candidate_datatypes;

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		/* Find the corresponding parameter in function declaration */

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		param_name = fp_iterator.search(call_param_name);

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		if(param_name == NULL) return false;

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		/* Get the parameter data type */

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		param_datatype = base_type(fp_iterator.param_type());

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		/* Get the parameter direction: IN, OUT, IN_OUT */

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

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		/* check whether direction (IN, OUT, IN_OUT) and assignment types (:= , =>) are compatible !!! */

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		if          (function_call_param_iterator_c::assign_in  == call_param_dir) {

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			if ((function_param_iterator_c::direction_in    != param_dir) &&

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			    (function_param_iterator_c::direction_inout != param_dir))

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				return false;

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		} else if   (function_call_param_iterator_c::assign_out == call_param_dir) {

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			if ((function_param_iterator_c::direction_out   != param_dir))

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				return false;

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		} else ERROR;

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		/* check whether one of the candidate_data_types of the value being passed is the same as the param_type */

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		if (search_in_candidate_datatype_list(param_datatype, call_param_types) < 0)

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			return false; /* return false if param_type not in the list! */

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		/* If this is the first parameter, then copy the datatype to *first_param_datatype */

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		if (is_first_param)

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			if (NULL != first_param_datatype)

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				*first_param_datatype = param_datatype;

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		is_first_param = false;

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	}

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	/* call is compatible! */

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	return true;

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}

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/* Handle a generic function call!

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 * Assumes that the parameter_list containing the values being passed in this function invocation

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 * has already had all the candidate_datatype lists filled in!

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 *

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 * All parameters being passed to the called function MUST be in the parameter list to which f_call points to!

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 * This means that, for non formal function calls in IL, de current (default value) must be artificially added to the

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 * beginning of the parameter list BEFORE calling handle_function_call().

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 */

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/*

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typedef struct {

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  symbol_c *function_name,

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  symbol_c *nonformal_operand_list,

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  symbol_c *   formal_operand_list,

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  std::vector <symbol_c *> &candidate_functions,  

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  symbol_c &*called_function_declaration,

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  int      &extensible_param_count

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} generic_function_call_t;

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*/

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/*

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void narrow_candidate_datatypes_c::narrow_function_invocation(symbol_c *fcall, generic_function_call_t fcall_data) {

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void *fill_candidate_datatypes_c::handle_function_call(symbol_c *f_call, symbol_c *function_name, invocation_type_t invocation_type,

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                                                       std::vector <symbol_c *> *candidate_datatypes,

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                                                       std::vector <symbol_c *> *candidate_functions) {

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  */

   361

void fill_candidate_datatypes_c::handle_function_call(symbol_c *fcall, generic_function_call_t fcall_data) {

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	function_declaration_c *f_decl;

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	list_c *parameter_list;

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	list_c *parameter_candidate_datatypes;

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	symbol_c *returned_parameter_type;

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	if (debug) std::cout << "function()\n";

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   369

	function_symtable_t::iterator lower = function_symtable.lower_bound(fcall_data.function_name);

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	function_symtable_t::iterator upper = function_symtable.upper_bound(fcall_data.function_name);

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	/* If the name of the function being called is not found in the function symbol table, then this is an invalid call */

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	/* Since the lexical parser already checks for this, then if this occurs then we have an internal compiler error. */

   373

	if (lower == function_symtable.end()) ERROR;

   374

   375

	/* Look for all compatible function declarations, and add their return datatypes 

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	 * to the candidate_datatype list of this function invocation. 

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	 *

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	 * If only one function exists, we add its return datatype to the candidate_datatype list,

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	 * even if the parameters passed to it are invalid.

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	 * This guarantees that the remainder of the expression in which the function call is inserted

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	 * is treated as if the function call returns correctly, and therefore does not generate

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	 * spurious error messages.

   383

	 * Even if the parameters to the function call are invalid, doing this is still safe, as the 

   384

	 * expressions inside the function call will themselves have erros and will  guarantee that 

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	 * compilation is aborted in stage3 (in print_datatypes_error_c).

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	 */

   387

	if (function_symtable.multiplicity(fcall_data.function_name) == 1) {

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		f_decl = function_symtable.get_value(lower);

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		returned_parameter_type = base_type(f_decl->type_name);

   390

		if (add_datatype_to_candidate_list(fcall, returned_parameter_type))

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			/* we only add it to the function declaration list if this entry was not already present in the candidate datatype list! */

   392

			fcall_data.candidate_functions.push_back(f_decl);

   393

   394

	}

   395

	for(; lower != upper; lower++) {

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		bool compatible = false;

   397

   398

		f_decl = function_symtable.get_value(lower);

   399

		/* Check if function declaration in symbol_table is compatible with parameters */

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		if (NULL != fcall_data.nonformal_operand_list) compatible=match_nonformal_call(fcall, f_decl);

   401

		if (NULL != fcall_data.   formal_operand_list) compatible=   match_formal_call(fcall, f_decl);

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		if (compatible) {

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			/* Add the data type returned by the called functions. 

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			 * However, only do this if this data type is not already present in the candidate_datatypes list_c

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			 */

   406

			returned_parameter_type = base_type(f_decl->type_name);		

   407

			if (add_datatype_to_candidate_list(fcall, returned_parameter_type))

   408

				/* we only add it to the function declaration list if this entry was not already present in the candidate datatype list! */

   409

				fcall_data.candidate_functions.push_back(f_decl);

   410

		}

   411

	}

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	if (debug) std::cout << "end_function() [" << fcall->candidate_datatypes.size() << "] result.\n";

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	return;

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}

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   416

   417

/* handle implicit FB call in IL.

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 * e.g.  CLK ton_var

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 *        CU counter_var

   420

 */

   421

void *fill_candidate_datatypes_c::handle_implicit_il_fb_call(symbol_c *il_instruction, const char *param_name, symbol_c *&called_fb_declaration) {

   422

	symbol_c *fb_type_id = search_varfb_instance_type->get_basetype_id(il_operand);

   423

  	/* Although a call to a non-declared FB is a semantic error, this is currently caught by stage 2! */

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	if (NULL == fb_type_id) ERROR;

   425

   426

	function_block_declaration_c *fb_decl = function_block_type_symtable.find_value(fb_type_id);

   427

	if (function_block_type_symtable.end_value() == fb_decl)

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		/* The il_operand is not the name of a FB instance. Most probably it is the name of a variable of some other type.

   429

		 * this is a semantic error.

   430

		 */

   431

		fb_decl = NULL;

   432

   433

	/* The narrow_candidate_datatypes_c does not rely on this called_fb_declaration pointer being == NULL to conclude that

   434

	 * we have a datatype incompatibility error, so we set it to fb_decl to allow the print_datatype_error_c to print out

   435

	 * more informative error messages!

   436

	 */

   437

	called_fb_declaration = fb_decl;

   438

   439

	/* This implicit FB call does not change the value stored in the current/default IL variable */

   440

	/* It does, however, require that the datatype be compatible with the input parameter of the FB being called. 

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	 * If we were to follow the filling & narrowing algorithm correctly (implemented in fill_candidate_datatypes_c

   442

	 * & narrow_candidate_datatypes_c respectively), we should be restricting the candidate_datatpes to the datatypes

   443

	 * that are compatible to the FB call. 

   444

	 * However, doing the above will often result in some very confusing error messages for the user, especially in the case

   445

	 * in which the FB call is wrong, so the resulting cadidate datatypes is an empty list. In this case, the user would see

   446

	 * many error messages related to the IL instructions that follow the FB call, even though those IL instructions may be perfectly

   447

	 * correct.

   448

	 * For now, we will simply let the narrow_candidate_datatypes_c verify if the datatypes are compatible (something that should be done

   449

	 * here).

   450

	 */

   451

	if (NULL != prev_il_instruction)

   452

		il_instruction->candidate_datatypes = prev_il_instruction->candidate_datatypes; 

   453

   454

	if (debug) std::cout << "handle_implicit_il_fb_call() [" << prev_il_instruction->candidate_datatypes.size() << "] ==> " << il_instruction->candidate_datatypes.size() << " result.\n";

   455

	return NULL;

   456

}

   457

   458

   459

   460

   461

/* handle a binary IL operator, like ADD, SUB, etc... */

   462

void *fill_candidate_datatypes_c::handle_binary_operator(const struct widen_entry widen_table[], symbol_c *symbol, symbol_c *l_expr, symbol_c *r_expr) {

   463

	if (NULL == l_expr) /* if no prev_il_instruction */

   464

		return NULL; 

   465

   466

	for(unsigned int i = 0; i < l_expr->candidate_datatypes.size(); i++)

   467

		for(unsigned int j = 0; j < r_expr->candidate_datatypes.size(); j++)

   468

			/* NOTE: add_datatype_to_candidate_list() will only really add the datatype if it is != NULL !!! */

   469

			add_datatype_to_candidate_list(symbol, widening_conversion(l_expr->candidate_datatypes[i], r_expr->candidate_datatypes[j], widen_table));

   471

	if (debug) std::cout <<  "[" << l_expr->candidate_datatypes.size() << "," << r_expr->candidate_datatypes.size() << "] ==> "  << symbol->candidate_datatypes.size() << " result.\n";

   472

	return NULL;

   473

}

   474

   475

   476

/* handle a binary ST expression, like '+', '-', etc... */

   477

void *fill_candidate_datatypes_c::handle_binary_expression(const struct widen_entry widen_table[], symbol_c *symbol, symbol_c *l_expr, symbol_c *r_expr) {

   478

	l_expr->accept(*this);

   479

	r_expr->accept(*this);

   480

	return handle_binary_operator(widen_table, symbol, l_expr, r_expr);

   481

}

   482

   483

   484

   485

   486

/* a helper function... */

   487

symbol_c *fill_candidate_datatypes_c::base_type(symbol_c *symbol) {

   488

	/* NOTE: symbol == NULL is valid. It will occur when, for e.g., an undefined/undeclared symbolic_variable is used

   489

	 *       in the code.

   490

	 */

   491

	if (symbol == NULL) return NULL;

   492

	return (symbol_c *)symbol->accept(search_base_type);

   493

}

   494

   495

/*********************/

   496

/* B 1.2 - Constants */

   497

/*********************/

   498

/******************************/