1 /*

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

     3  *

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

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

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

     7  *

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

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

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

    11  *  (at your option) any later version.

    12  *

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

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

    15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    16  *  GNU General Public License for more details.

    17  *

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

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

    20  *

    21  *

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

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

    24  */

    25 

    26 /*

    27  * An IEC 61131-3 compiler.

    28  *

    29  * Based on the

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

    31  *

    32  */

    33 

    34 

    35 /* NOTE: The algorithm implemented here assumes that candidate datatype lists have already been filled!

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

    37  */

    38 

    39 

    40 /*

    41  *  Choose, from the list of all the possible datatypes each expression may take, the single datatype that it will in fact take.

    42  *  The resulting (chosen) datatype, will be stored in the symbol_c.datatype variable, leaving the candidate datatype list untouched!

    43  * 

    44  *  For rvalue expressions, this decision will be based on the datatype of the lvalue expression.

    45  *  For lvalue expressions, the candidate datatype list should have a single entry.

    46  * 

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

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

    49  * 

    50  *  In this class, the datatype of '0' will be set to the same datatype as the 'foo' variable.

    51  *  If the intersection of the candidate datatype lists of the left and right side expressions is empty, 

    52  *  then a datatype error has been found, and the datatype is either left at NULL, or set to a pointer of an invalid_type_name_c object!

    53  */

    54 

    55 

    56 #include "narrow_candidate_datatypes.hh"

    57 #include "datatype_functions.hh"

    58 #include <typeinfo>

    59 #include <list>

    60 #include <string>

    61 #include <string.h>

    62 #include <strings.h>

    63 

    64 

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

    66 static int debug = 0;

    67 

    68 narrow_candidate_datatypes_c::narrow_candidate_datatypes_c(symbol_c *ignore) {

    69 }

    70 

    71 narrow_candidate_datatypes_c::~narrow_candidate_datatypes_c(void) {

    72 }

    73 

    74 

    75 /* Only set the symbol's desired datatype to 'datatype' if that datatype is in the candidate_datatype list */

    76 static void set_datatype(symbol_c *datatype, symbol_c *symbol) {

    77   

    78 	/* If we are trying to set to the undefined type, and the symbol's datatype has already been set to something else, 

    79 	 * we abort the compoiler as I don't think this should ever occur. 

    80 	 * NOTE: In order to handle JMPs to labels that come before the JMP itself, we run the narrow algorithm twice.

    81 	 *       This means that this situation may legally occur, so we cannot abort the compiler here!

    82 	 */

    83 // 	if ((NULL == datatype) && (NULL != symbol->datatype)) ERROR;

    84  	if ((NULL == datatype) && (NULL != symbol->datatype)) return;

    85 	if ((NULL == datatype) && (NULL == symbol->datatype)) return;

    86 	

    87 	if (search_in_candidate_datatype_list(datatype, symbol->candidate_datatypes) < 0)

    88 		symbol->datatype = &(search_constant_type_c::invalid_type_name);   

    89 	else {

    90 		if (NULL == symbol->datatype)   

    91 			/* not yet set to anything, so we set it to the requested data type */

    92 			symbol->datatype = datatype; 

    93 		else {

    94 			/* had already been set previously to some data type. Let's check if they are the same! */

    95 			if (!is_type_equal(symbol->datatype, datatype))

    96 				symbol->datatype = &(search_constant_type_c::invalid_type_name);

    97 // 			else 

    98 				/* we leave it unchanged, as it is the same as the requested data type! */

    99 		}

   100 	}

   101 }

   102 

   103 

   104 

   105 /* Only set the symbol's desired datatype to 'datatype' if that datatype is in the candidate_datatype list */

   106 // static void set_datatype_in_prev_il_instructions(symbol_c *datatype, std::vector <symbol_c *> prev_il_instructions) {

   107 static void set_datatype_in_prev_il_instructions(symbol_c *datatype, il_instruction_c *symbol) {

   108 	if (NULL == symbol) ERROR;

   109 	for (unsigned int i = 0; i < symbol->prev_il_instruction.size(); i++)

   110 		set_datatype(datatype, symbol->prev_il_instruction[i]);

   111 }

   112 

   113 

   114 

   115 bool narrow_candidate_datatypes_c::is_widening_compatible(const struct widen_entry widen_table[], symbol_c *left_type, symbol_c *right_type, symbol_c *result_type, bool *deprecated_status) {

   116 	/* NOTE: According to our algorithm, left_type and right_type should never by NULL (if they are, we have an internal compiler error!

   117 	 *       However, result_type may be NULL if the code has a data type semantic error!

   118 	 */

   119 	if ((NULL == left_type) || (NULL == right_type) || (NULL == result_type))

   120 		return false;

   121 

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

   123 		if        ((typeid(*left_type)   == typeid(*widen_table[k].left))

   124 		        && (typeid(*right_type)  == typeid(*widen_table[k].right))

   125 			&& (typeid(*result_type) == typeid(*widen_table[k].result))) {

   126 			if (NULL != deprecated_status)

   127 				*deprecated_status = (widen_table[k].status == widen_entry::deprecated);

   128 			return true;

   129 		}

   130 	}

   131 	return false;

   132 }

   133 

   134 /*

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

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

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

   138  */

   139 void narrow_candidate_datatypes_c::narrow_nonformal_call(symbol_c *f_call, symbol_c *f_decl, int *ext_parm_count) {

   140 	symbol_c *call_param_value,  *param_type;

   141 	identifier_c *param_name;

   142 	function_param_iterator_c       fp_iterator(f_decl);

   143 	function_call_param_iterator_c fcp_iterator(f_call);

   144 	int extensible_parameter_highest_index = -1;

   145 	unsigned int i;

   146 

   147 	if (NULL != ext_parm_count) *ext_parm_count = -1;

   148 

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

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

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

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

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

   154 		 */

   155 		do {

   156 			param_name = fp_iterator.next();

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

   158 			/* This error should have been caught in fill_candidate_datatypes_c, but may occur here again when we handle FB invocations! 

   159 			 * In this case, we carry on analysing the code in order to be able to provide relevant error messages

   160 			 * for that code too!

   161 			 */

   162 			if(param_name == NULL) break;

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

   164 

   165 		/* Set the desired datatype for this parameter, and call it recursively. */

   166 		/* Note that if the call has more parameters than those declared in the function/FB declaration,

   167 		 * we may be setting this to NULL!

   168 		 */

   169 		symbol_c *desired_datatype = base_type(fp_iterator.param_type());

   170 		if ((NULL != param_name) && (NULL == desired_datatype)) ERROR;

   171 		if ((NULL == param_name) && (NULL != desired_datatype)) ERROR;

   172 

   173 		/* NOTE: When we are handling a nonformal function call made from IL, the first parameter is the 'default' or 'current'

   174 		 *       il value. However, a pointer to a copy of the prev_il_instruction is pre-pended into the operand list, so 

   175 		 *       the call 

   176 		 *       call_param_value->accept(*this);

   177 		 *       may actually be calling an object of the base symbol_c .

   178 		 */

   179 		set_datatype(desired_datatype, call_param_value);

   180 		call_param_value->accept(*this);

   181 

   182 		if (NULL != param_name) 

   183 			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   184 				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   185 	}

   186 	/* In the case of a call to an extensible function, we store the highest index 

   187 	 * of the extensible parameters this particular call uses, in the symbol_c object

   188 	 * of the function call itself!

   189 	 * In calls to non-extensible functions, this value will be set to -1.

   190 	 * This information is later used in stage4 to correctly generate the

   191 	 * output code.

   192 	 */

   193 	if ((NULL != ext_parm_count) && (extensible_parameter_highest_index >=0) /* if call to extensible function */)

   194 		*ext_parm_count = 1 + extensible_parameter_highest_index - fp_iterator.first_extensible_param_index();

   195 }

   196 

   197 

   198 

   199 void narrow_candidate_datatypes_c::narrow_formal_call(symbol_c *f_call, symbol_c *f_decl, int *ext_parm_count) {

   200 	symbol_c *call_param_value, *call_param_name, *param_type;

   201 	symbol_c *verify_duplicate_param;

   202 	identifier_c *param_name;

   203 	function_param_iterator_c       fp_iterator(f_decl);

   204 	function_call_param_iterator_c fcp_iterator(f_call);

   205 	int extensible_parameter_highest_index = -1;

   206 	identifier_c *extensible_parameter_name;

   207 	unsigned int i;

   208 

   209 	if (NULL != ext_parm_count) *ext_parm_count = -1;

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

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

   212 

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

   214 		call_param_value = fcp_iterator.get_current_value();

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

   216 		if (NULL == call_param_value) ERROR;

   217 

   218 		/* Find the corresponding parameter in function declaration */

   219 		param_name = fp_iterator.search(call_param_name);

   220 

   221 		/* Set the desired datatype for this parameter, and call it recursively. */

   222 		/* NOTE: When handling a FB call, this narrow_formal_call() may be called to analyse

   223 		 *       an invalid FB call (call with parameters that do not exist on the FB declaration).

   224 		 *       For this reason, the param_name may come out as NULL!

   225 		 */

   226 		symbol_c *desired_datatype = base_type(fp_iterator.param_type());

   227 		if ((NULL != param_name) && (NULL == desired_datatype)) ERROR;

   228 		if ((NULL == param_name) && (NULL != desired_datatype)) ERROR;

   229 

   230 		/* set the desired data type for this parameter */

   231 		set_datatype(desired_datatype, call_param_value);

   232 		/* And recursively call that parameter/expression, so it can propagate that info */

   233 		call_param_value->accept(*this);

   234 

   235 		/* set the extensible_parameter_highest_index, which will be needed in stage 4 */

   236 		/* This value says how many extensible parameters are being passed to the standard function */

   237 		if (NULL != param_name) 

   238 			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   239 				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   240 	}

   241 	/* call is compatible! */

   242 

   243 	/* In the case of a call to an extensible function, we store the highest index 

   244 	 * of the extensible parameters this particular call uses, in the symbol_c object

   245 	 * of the function call itself!

   246 	 * In calls to non-extensible functions, this value will be set to -1.

   247 	 * This information is later used in stage4 to correctly generate the

   248 	 * output code.

   249 	 */

   250 	if ((NULL != ext_parm_count) && (extensible_parameter_highest_index >=0) /* if call to extensible function */)

   251 		*ext_parm_count = 1 + extensible_parameter_highest_index - fp_iterator.first_extensible_param_index();

   252 }

   253 

   254 

   255 /*

   256 typedef struct {

   257   symbol_c *function_name,

   258   symbol_c *nonformal_operand_list,

   259   symbol_c *   formal_operand_list,

   260 

   261   std::vector <symbol_c *> &candidate_functions,  

   262   symbol_c &*called_function_declaration,

   263   int      &extensible_param_count

   264 } generic_function_call_t;

   265 */

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

   267 	/* set the called_function_declaration. */

   268 	fcall_data.called_function_declaration = NULL;

   269 

   270 	/* set the called_function_declaration taking into account the datatype that we need to return */

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

   272 		if (is_type_equal(fcall->candidate_datatypes[i], fcall->datatype)) {

   273 			fcall_data.called_function_declaration = fcall_data.candidate_functions[i];

   274 			break;

   275 		}

   276 	}

   277 

   278 	/* NOTE: If we can't figure out the declaration of the function being called, this is not 

   279 	 *       necessarily an internal compiler error. It could be because the symbol->datatype is NULL

   280 	 *       (because the ST code being analysed has an error _before_ this function invocation).

   281 	 *       However, we don't just give, up, we carry on recursivly analysing the code, so as to be

   282 	 *       able to print out any error messages related to the parameters being passed in this function 

   283 	 *       invocation.

   284 	 */

   285 	/* if (NULL == symbol->called_function_declaration) ERROR; */

   286 	if (fcall->candidate_datatypes.size() == 1) {

   287 		/* If only one function declaration, then we use that (even if symbol->datatypes == NULL)

   288 		 * so we can check for errors in the expressions used to pass parameters in this

   289 		 * function invocation.

   290 		 */

   291 		fcall_data.called_function_declaration = fcall_data.candidate_functions[0];

   292 	}

   293 

   294 	/* If an overloaded function is being invoked, and we cannot determine which version to use,

   295 	 * then we can not meaningfully verify the expressions used inside that function invocation.

   296 	 * We simply give up!

   297 	 */

   298 	if (NULL == fcall_data.called_function_declaration)

   299 		return;

   300 

   301 	if (NULL != fcall_data.nonformal_operand_list)  narrow_nonformal_call(fcall, fcall_data.called_function_declaration, &(fcall_data.extensible_param_count));

   302 	if (NULL != fcall_data.   formal_operand_list)     narrow_formal_call(fcall, fcall_data.called_function_declaration, &(fcall_data.extensible_param_count));

   303 

   304 	return;

   305 }

   306 

   307 

   308 

   309 

   310 /* narrow implicit FB call in IL.

   311  * e.g.  CLK ton_var

   312  *        CU counter_var

   313  *

   314  * The algorithm will be to build a fake il_fb_call_c equivalent to the implicit IL FB call, and let 

   315  * the visit(il_fb_call_c *) method handle it!

   316  */

   317 void *narrow_candidate_datatypes_c::narrow_implicit_il_fb_call(symbol_c *il_instruction, const char *param_name, symbol_c *&called_fb_declaration) {

   318 

   319 	/* set the datatype of the il_operand, this is, the FB being called! */

   320 	if (NULL != il_operand) {

   321 		/* only set it if it is in the candidate datatypes list! */  

   322 		set_datatype(called_fb_declaration, il_operand);

   323 		il_operand->accept(*this);

   324 	}

   325 	symbol_c *fb_decl = il_operand->datatype;

   326 

   327 	if (0 == fake_prev_il_instruction->prev_il_instruction.size()) {

   328 		/* This IL implicit FB call (e.g. CLK ton_var) is not preceded by another IL instruction

   329 		 * (or list of instructions) that will set the IL current/default value.

   330 		 * We cannot proceed verifying type compatibility of something that does not exist.

   331 		 */

   332 		return NULL;

   333 	}

   334 

   335 	if (NULL == fb_decl) {

   336 		/* the il_operand is a not FB instance */

   337 		/* so we simply pass on the required datatype to the prev_il_instructions */

   338 		/* The invalid FB invocation will be caught in the print_datatypes_error_c by analysing NULL value in il_operand->datatype! */

   339 		set_datatype_in_prev_il_instructions(il_instruction->datatype, fake_prev_il_instruction);

   340 		return NULL;

   341 	}

   342 	

   343 

   344 	/* The value being passed to the 'param_name' parameter is actually the prev_il_instruction.

   345 	 * However, we do not place that object directly in the fake il_param_list_c that we will be

   346 	 * creating, since the visit(il_fb_call_c *) method will recursively call every object in that list.

   347 	 * The il_prev_intruction object will be visited once we have handled this implici IL FB call

   348 	 * (called from the instruction_list_c for() loop that works backwards). We DO NOT want to visit it twice.

   349 	 * (Anyway, if we let the visit(il_fb_call_c *) recursively visit the current prev_il_instruction, this pointer

   350 	 * would be changed to the IL instruction coming before the current prev_il_instruction! => things would get all messed up!)

   351 	 * The easiest way to work around this is to simply use a new object, and copy the relevant details to that object!

   352 	 */

   353 	symbol_c param_value = *fake_prev_il_instruction; /* copy the candidate_datatypes list ! */

   354 

   355 	identifier_c variable_name(param_name);

   356 	// SYM_REF1(il_assign_operator_c, variable_name)

   357 	il_assign_operator_c il_assign_operator(&variable_name);  

   358 	// SYM_REF3(il_param_assignment_c, il_assign_operator, il_operand, simple_instr_list)

   359 	il_param_assignment_c il_param_assignment(&il_assign_operator, &param_value/*il_operand*/, NULL);

   360 	il_param_list_c il_param_list;

   361 	il_param_list.add_element(&il_param_assignment);

   362 	// SYM_REF4(il_fb_call_c, il_call_operator, fb_name, il_operand_list, il_param_list, symbol_c *called_fb_declaration)

   363 	CAL_operator_c CAL_operator;

   364 	il_fb_call_c il_fb_call(&CAL_operator, il_operand, NULL, &il_param_list);

   365 	        

   366 	/* A FB call does not return any datatype, but the IL instructions that come after this

   367 	 * FB call may require a specific datatype in the il current/default variable, 

   368 	 * so we must pass this information up to the IL instruction before the FB call, since it will

   369 	 * be that IL instruction that will be required to produce the desired dtataype.

   370 	 *

   371 	 * The above will be done by the visit(il_fb_call_c *) method, so we must make sure to

   372 	 * correctly set up the il_fb_call.datatype variable!

   373 	 */

   374 	il_fb_call.called_fb_declaration = called_fb_declaration;

   375 	il_fb_call.accept(*this);

   376 

   377 	/* set the required datatype of the previous IL instruction! */

   378 	/* NOTE:

   379 	 * When handling these implicit IL calls, the parameter_value being passed to the FB parameter

   380 	 * is actually the prev_il_instruction.

   381 	 * 

   382 	 * However, since the FB call does not change the value in the current/default IL variable, this value

   383 	 * must also be used ny the IL instruction coming after this FB call.

   384 	 *

   385 	 * This means that we have two consumers/users for the same value. 

   386 	 * We must therefore check whether the datatype required by the IL instructions following this FB call 

   387 	 * is the same as that required for the first parameter. If not, then we have a semantic error,

   388 	 * and we set it to invalid_type_name.

   389 	 *

   390 	 * However, we only do that if:

   391 	 *  - The IL instruction that comes after this IL FB call actually asked this FB call for a specific 

   392 	 *     datatype in the current/default vairable, once this IL FB call returns.

   393 	 *     However, sometimes, (for e.g., this FB call is the last in the IL list) the subsequent FB to not aks this

   394 	 *     FB call for any datatype. In that case, then the datatype required to pass to the first parameter of the

   395 	 *     FB call must be left unchanged!

   396 	 */

   397 	if ((NULL == il_instruction->datatype) || (is_type_equal(param_value.datatype, il_instruction->datatype))) {

   398 		set_datatype_in_prev_il_instructions(param_value.datatype, fake_prev_il_instruction);

   399 	} else {

   400 		set_datatype_in_prev_il_instructions(&search_constant_type_c::invalid_type_name, fake_prev_il_instruction);

   401 	}

   402 	return NULL;

   403 }

   404 

   405 

   406 /* a helper function... */

   407 symbol_c *narrow_candidate_datatypes_c::base_type(symbol_c *symbol) {

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

   409 	 *       in the code.

   410 	 */

   411 	if (symbol == NULL) return NULL;

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

   413 }

   414 

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

   416 /* B 1.2 - Constants */

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

   418 

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

   420 /* B 1.3 - Data types */

   421 /**********************/

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

   423 /* B 1.3.3 - Derived data types */

   424 /********************************/

   425 /* simple_specification ASSIGN constant */

   426 // SYM_REF2(simple_spec_init_c, simple_specification, constant)

   427 void *narrow_candidate_datatypes_c::visit(simple_spec_init_c *symbol) {

   428 	if (symbol->candidate_datatypes.size() == 1)

   429 	  symbol->datatype = symbol->candidate_datatypes[0];

   430 	  

   431 	if (symbol->simple_specification->candidate_datatypes.size() == 1)

   432 	  symbol->simple_specification->datatype = symbol->simple_specification->candidate_datatypes[0];

   433 

   434 	if (NULL != symbol->constant) {

   435 		set_datatype(symbol->datatype, symbol->constant);

   436 		symbol->constant->accept(*this);

   437 	}

   438 	return NULL;

   439 }

   440 

   441 

   442 

   443 /*  signed_integer DOTDOT signed_integer */

   444 // SYM_REF2(subrange_c, lower_limit, upper_limit)

   445 void *narrow_candidate_datatypes_c::visit(subrange_c *symbol) {

   446 	symbol->lower_limit->datatype = symbol->datatype;

   447 	symbol->lower_limit->accept(*this);

   448 	symbol->upper_limit->datatype = symbol->datatype;

   449 	symbol->upper_limit->accept(*this);

   450 	return NULL;

   451 }

   452 

   453 

   454 /*********************/

   455 /* B 1.4 - Variables */

   456 /*********************/

   457 

   458 /********************************************/

   459 /* B 1.4.1 - Directly Represented Variables */

   460 /********************************************/

   461 

   462 /*************************************/

   463 /* B 1.4.2 - Multi-element variables */

   464 /*************************************/

   465 /*  subscripted_variable '[' subscript_list ']' */

   466 // SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   467 void *narrow_candidate_datatypes_c::visit(array_variable_c *symbol) {

   468 	/* we need to check the data types of the expressions used for the subscripts... */

   469 	symbol->subscript_list->accept(*this);

   470 	return NULL;

   471 }

   472 

   473 

   474 /* subscript_list ',' subscript */

   475 // SYM_LIST(subscript_list_c)

   476 void *narrow_candidate_datatypes_c::visit(subscript_list_c *symbol) {

   477 	for (int i = 0; i < symbol->n; i++) {

   478 		for (unsigned int k = 0; k < symbol->elements[i]->candidate_datatypes.size(); k++) {

   479 			if (is_ANY_INT_type(symbol->elements[i]->candidate_datatypes[k]))

   480 				symbol->elements[i]->datatype = symbol->elements[i]->candidate_datatypes[k];

   481 		}

   482 		symbol->elements[i]->accept(*this);

   483 	}

   484 	return NULL;  

   485 }

   486 

   487 

   488 

   489 

   490 /******************************************/

   491 /* B 1.4.3 - Declaration & Initialisation */

   492 /******************************************/

   493 

   494 void *narrow_candidate_datatypes_c::visit(var1_list_c *symbol) {

   495 #if 0   /* We don't really need to set the datatype of each variable. We just check the declaration itself! */

   496   for(int i = 0; i < symbol->n; i++) {

   497     if (symbol->elements[i]->candidate_datatypes.size() == 1)

   498       symbol->elements[i]->datatype = symbol->elements[i]->candidate_datatypes[0];

   499   }

   500 #endif

   501   return NULL;

   502 }  

   503 

   504 

   505 /*  AT direct_variable */

   506 // SYM_REF1(location_c, direct_variable)

   507 void *narrow_candidate_datatypes_c::visit(location_c *symbol) {

   508   set_datatype(symbol->datatype, symbol->direct_variable);

   509   symbol->direct_variable->accept(*this); /* currently does nothing! */

   510   return NULL;

   511 }

   512 

   513 

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

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

   516 // SYM_REF3(located_var_decl_c, variable_name, location, located_var_spec_init)

   517 void *narrow_candidate_datatypes_c::visit(located_var_decl_c *symbol) {

   518   /* let the var_spec_init set its own symbol->datatype value */

   519   symbol->located_var_spec_init->accept(*this);

   520   

   521   if (NULL != symbol->variable_name)

   522     set_datatype(symbol->located_var_spec_init->datatype, symbol->variable_name);

   523     

   524   set_datatype(symbol->located_var_spec_init->datatype, symbol->location);

   525   symbol->location->accept(*this);

   526   return NULL;

   527 }

   528 

   529 

   530 /************************************/

   531 /* B 1.5 Program organization units */

   532 /************************************/

   533 /*********************/

   534 /* B 1.5.1 Functions */

   535 /*********************/

   536 void *narrow_candidate_datatypes_c::visit(function_declaration_c *symbol) {

   537 	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);

   538 	symbol->var_declarations_list->accept(*this);

   539 	if (debug) printf("Narrowing candidate data types list in body of function %s\n", ((token_c *)(symbol->derived_function_name))->value);

   540 	symbol->function_body->accept(*this);

   541 	delete search_varfb_instance_type;

   542 	search_varfb_instance_type = NULL;

   543 	return NULL;

   544 }

   545 

   546 /***************************/

   547 /* B 1.5.2 Function blocks */

   548 /***************************/

   549 void *narrow_candidate_datatypes_c::visit(function_block_declaration_c *symbol) {

   550 	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);

   551 	symbol->var_declarations->accept(*this);

   552 	if (debug) printf("Narrowing candidate data types list in body of FB %s\n", ((token_c *)(symbol->fblock_name))->value);

   553 	symbol->fblock_body->accept(*this);

   554 	delete search_varfb_instance_type;

   555 	search_varfb_instance_type = NULL;

   556 	return NULL;

   557 }

   558 

   559 /********************/

   560 /* B 1.5.3 Programs */

   561 /********************/

   562 void *narrow_candidate_datatypes_c::visit(program_declaration_c *symbol) {

   563 	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);

   564 	symbol->var_declarations->accept(*this);

   565 	if (debug) printf("Narrowing candidate data types list in body of program %s\n", ((token_c *)(symbol->program_type_name))->value);

   566 	symbol->function_block_body->accept(*this);

   567 	delete search_varfb_instance_type;

   568 	search_varfb_instance_type = NULL;

   569 	return NULL;

   570 }

   571 

   572 

   573 /********************************/

   574 /* B 1.7 Configuration elements */

   575 /********************************/

   576 void *narrow_candidate_datatypes_c::visit(configuration_declaration_c *symbol) {

   577 	// TODO !!!

   578 	/* for the moment we must return NULL so semantic analysis of remaining code is not interrupted! */

   579 	return NULL;

   580 }

   581 

   582 

   583 /****************************************/

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

   585 /****************************************/

   586 /***********************************/

   587 /* B 2.1 Instructions and Operands */

   588 /***********************************/

   589 

   590 /*| instruction_list il_instruction */

   591 // SYM_LIST(instruction_list_c)

   592 void *narrow_candidate_datatypes_c::visit(instruction_list_c *symbol) {

   593 	/* In order to execute the narrow algoritm correctly, we need to go through the instructions backwards,

   594 	 * so we can not use the base class' visitor 

   595 	 */

   596 	/* In order to execute the narrow algoritm correctly

   597 	 * in IL instruction lists containing JMPs to labels that come before the JMP instruction

   598 	 * itself, we need to run the narrow algorithm twice on the Instruction List.

   599 	 * e.g.:  ...

   600 	 *          ld 23

   601 	 *   label1:st byte_var

   602 	 *          ld 34

   603 	 *          JMP label1     

   604 	 *

   605 	 * Note that the second time we run the narrow, most of the datatypes are already filled

   606 	 * in, so it will be able to produce tha correct datatypes for the IL instruction referenced

   607 	 * by the label, as in the 2nd pass we already know the datatypes of the JMP instruction!

   608 	 */

   609 	for(int j = 0; j < 2; j++) {

   610 		for(int i = symbol->n-1; i >= 0; i--) {

   611 			symbol->elements[i]->accept(*this);

   612 		}

   613 	}

   614 	return NULL;

   615 }

   616 

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

   618 // SYM_REF2(il_instruction_c, label, il_instruction)

   619 // void *visit(instruction_list_c *symbol);

   620 void *narrow_candidate_datatypes_c::visit(il_instruction_c *symbol) {

   621 	if (NULL == symbol->il_instruction) {

   622 		/* this empty/null il_instruction cannot generate the desired datatype. We pass on the request to the previous il instruction. */

   623 		set_datatype_in_prev_il_instructions(symbol->datatype, symbol);

   624 	} else {

   625 		il_instruction_c tmp_prev_il_instruction(NULL, NULL);

   626 		/* the narrow algorithm will need access to the intersected candidate_datatype lists of all prev_il_instructions, as well as the 

   627 		 * list of the prev_il_instructions.

   628 		 * Instead of creating two 'global' (within the class) variables, we create a single il_instruction_c variable (fake_prev_il_instruction),

   629 		 * and shove that data into this single variable.

   630 		 */

   631 		tmp_prev_il_instruction.prev_il_instruction = symbol->prev_il_instruction;

   632 		intersect_prev_candidate_datatype_lists(&tmp_prev_il_instruction);

   633 		/* Tell the il_instruction the datatype that it must generate - this was chosen by the next il_instruction (remember: we are iterating backwards!) */

   634 		fake_prev_il_instruction = &tmp_prev_il_instruction;

   635 		symbol->il_instruction->datatype = symbol->datatype;

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

   637 		fake_prev_il_instruction = NULL;

   638 	}

   639 	return NULL;

   640 }

   641 

   642 

   643 

   644 

   645 // void *visit(instruction_list_c *symbol);

   646 void *narrow_candidate_datatypes_c::visit(il_simple_operation_c *symbol) {

   647 	/* Tell the il_simple_operator the datatype that it must generate - this was chosen by the next il_instruction (we iterate backwards!) */

   648 	symbol->il_simple_operator->datatype = symbol->datatype;

   649 	/* recursive call to see whether data types are compatible */

   650 	il_operand = symbol->il_operand;

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

   652 	il_operand = NULL;

   653 	return NULL;

   654 }

   655 

   656 /* | function_name [il_operand_list] */

   657 /* NOTE: The parameters 'called_function_declaration' and 'extensible_param_count' are used to pass data between the stage 3 and stage 4. */

   658 // SYM_REF2(il_function_call_c, function_name, il_operand_list, symbol_c *called_function_declaration; int extensible_param_count;)

   659 void *narrow_candidate_datatypes_c::visit(il_function_call_c *symbol) {

   660 	/* The first parameter of a non formal function call in IL will be the 'current value' (i.e. the prev_il_instruction)

   661 	 * In order to be able to handle this without coding special cases, we will simply prepend that symbol

   662 	 * to the il_operand_list, and remove it after calling handle_function_call().

   663 	 * However, since handle_function_call() will be recursively calling all parameter, and we don't want

   664 	 * to do that for the prev_il_instruction (since it has already been visited by the fill_candidate_datatypes_c)

   665 	 * we create a new ____ symbol_c ____ object, and copy the relevant info to/from that object before/after

   666 	 * the call to handle_function_call().

   667 	 *

   668 	 * However, if no further paramters are given, then il_operand_list will be NULL, and we will

   669 	 * need to create a new object to hold the pointer to prev_il_instruction.

   670 	 * This change will also be undone at the end of this method.

   671 	 */

   672 	symbol_c param_value = *fake_prev_il_instruction; /* copy the candidate_datatypes list */

   673 	if (NULL == symbol->il_operand_list)  symbol->il_operand_list = new il_operand_list_c;

   674 	if (NULL == symbol->il_operand_list)  ERROR;

   675 

   676 	((list_c *)symbol->il_operand_list)->insert_element(&param_value, 0);

   677 

   678 	generic_function_call_t fcall_param = {

   679 		/* fcall_param.function_name               = */ symbol->function_name,

   680 		/* fcall_param.nonformal_operand_list      = */ symbol->il_operand_list,

   681 		/* fcall_param.formal_operand_list         = */ NULL,

   682 		/* enum {POU_FB, POU_function} POU_type    = */ generic_function_call_t::POU_function,

   683 		/* fcall_param.candidate_functions         = */ symbol->candidate_functions,

   684 		/* fcall_param.called_function_declaration = */ symbol->called_function_declaration,

   685 		/* fcall_param.extensible_param_count      = */ symbol->extensible_param_count

   686 	};

   687 

   688 	narrow_function_invocation(symbol, fcall_param);

   689 	set_datatype_in_prev_il_instructions(param_value.datatype, fake_prev_il_instruction);

   690 

   691 	/* Undo the changes to the abstract syntax tree we made above... */

   692 	((list_c *)symbol->il_operand_list)->remove_element(0);

   693 	if (((list_c *)symbol->il_operand_list)->n == 0) {

   694 		/* if the list becomes empty, then that means that it did not exist before we made these changes, so we delete it! */

   695 		delete 	symbol->il_operand_list;

   696 		symbol->il_operand_list = NULL;

   697 	}

   698 

   699 	return NULL;

   700 }

   701 

   702 

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

   704 // SYM_REF3(il_expression_c, il_expr_operator, il_operand, simple_instr_list);

   705 void *narrow_candidate_datatypes_c::visit(il_expression_c *symbol) {

   706   /* first handle the operation (il_expr_operator) that will use the result coming from the parenthesised IL list (i.e. simple_instr_list) */

   707   symbol->il_expr_operator->datatype = symbol->datatype;

   708   il_operand = symbol->simple_instr_list; /* This is not a bug! The parenthesised expression will be used as the operator! */

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

   710 

   711   /* now give the parenthesised IL list a chance to narrow the datatypes */

   712   /* The datatype that is must return was set by the call symbol->il_expr_operator->accept(*this) */

   713   il_instruction_c *save_fake_prev_il_instruction = fake_prev_il_instruction; /*this is not really necessary, but lets play it safe */

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

   715   fake_prev_il_instruction = save_fake_prev_il_instruction;

   716   return NULL;

   717 }

   718 

   719 

   720 

   721 

   722 /*  il_jump_operator label */

   723 void *narrow_candidate_datatypes_c::visit(il_jump_operation_c *symbol) {

   724   /* recursive call to fill the datatype */

   725   symbol->il_jump_operator->datatype = symbol->datatype;

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

   727   return NULL;

   728 }

   729 

   730 

   731 

   732 

   733 

   734 

   735 

   736 /*   il_call_operator prev_declared_fb_name

   737  * | il_call_operator prev_declared_fb_name '(' ')'

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

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

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

   741  */

   742 /* NOTE: The parameter 'called_fb_declaration'is used to pass data between stage 3 and stage4 (although currently it is not used in stage 4 */

   743 // SYM_REF4(il_fb_call_c, il_call_operator, fb_name, il_operand_list, il_param_list, symbol_c *called_fb_declaration)

   744 void *narrow_candidate_datatypes_c::visit(il_fb_call_c *symbol) {

   745 	symbol_c *fb_decl = symbol->called_fb_declaration;

   746 	

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

   748 	if (NULL == fb_decl) ERROR;

   749 	if (NULL != symbol->il_operand_list)  narrow_nonformal_call(symbol, fb_decl);

   750 	if (NULL != symbol->  il_param_list)     narrow_formal_call(symbol, fb_decl);

   751 

   752 	/* Let the il_call_operator (CAL, CALC, or CALCN) set the datatype of prev_il_instruction... */

   753 	symbol->il_call_operator->datatype = symbol->datatype;

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

   755 	return NULL;

   756 }

   757 

   758 

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

   760 /* NOTE: The parameter 'called_function_declaration' is used to pass data between the stage 3 and stage 4. */

   761 // SYM_REF2(il_formal_funct_call_c, function_name, il_param_list, symbol_c *called_function_declaration; int extensible_param_count;)

   762 void *narrow_candidate_datatypes_c::visit(il_formal_funct_call_c *symbol) {

   763 	generic_function_call_t fcall_param = {

   764 		/* fcall_param.function_name               = */ symbol->function_name,

   765 		/* fcall_param.nonformal_operand_list      = */ NULL,

   766 		/* fcall_param.formal_operand_list         = */ symbol->il_param_list,

   767 		/* enum {POU_FB, POU_function} POU_type    = */ generic_function_call_t::POU_function,

   768 		/* fcall_param.candidate_functions         = */ symbol->candidate_functions,

   769 		/* fcall_param.called_function_declaration = */ symbol->called_function_declaration,

   770 		/* fcall_param.extensible_param_count      = */ symbol->extensible_param_count

   771 	};

   772   

   773 	narrow_function_invocation(symbol, fcall_param);

   774 	/* The desired datatype of the previous il instruction was already set by narrow_function_invocation() */

   775 	return NULL;

   776 }

   777 

   778 

   779 //     void *visit(il_operand_list_c *symbol);

   780 

   781 

   782 /* | simple_instr_list il_simple_instruction */

   783 /* This object is referenced by il_expression_c objects */

   784 void *narrow_candidate_datatypes_c::visit(simple_instr_list_c *symbol) {

   785 	if (symbol->n > 0)

   786 		symbol->elements[symbol->n - 1]->datatype = symbol->datatype;

   787 

   788 	for(int i = symbol->n-1; i >= 0; i--) {

   789 		symbol->elements[i]->accept(*this);

   790 	}

   791 	return NULL;

   792 }

   793 

   794 

   795 // SYM_REF1(il_simple_instruction_c, il_simple_instruction, symbol_c *prev_il_instruction;)

   796 void *narrow_candidate_datatypes_c::visit(il_simple_instruction_c *symbol)	{

   797   if (symbol->prev_il_instruction.size() > 1) ERROR; /* There should be no labeled insructions inside an IL expression! */

   798     

   799   il_instruction_c tmp_prev_il_instruction(NULL, NULL);

   800   /* the narrow algorithm will need access to the intersected candidate_datatype lists of all prev_il_instructions, as well as the 

   801    * list of the prev_il_instructions.

   802    * Instead of creating two 'global' (within the class) variables, we create a single il_instruction_c variable (fake_prev_il_instruction),

   803    * and shove that data into this single variable.

   804    */

   805   if (symbol->prev_il_instruction.size() > 0)

   806     tmp_prev_il_instruction.candidate_datatypes = symbol->prev_il_instruction[0]->candidate_datatypes;

   807   tmp_prev_il_instruction.prev_il_instruction = symbol->prev_il_instruction;

   808   

   809    /* copy the candidate_datatypes list */

   810   fake_prev_il_instruction = &tmp_prev_il_instruction;

   811   symbol->il_simple_instruction->datatype = symbol->datatype;

   812   symbol->il_simple_instruction->accept(*this);

   813   fake_prev_il_instruction = NULL;

   814   return NULL;

   815 }

   816 

   817 //     void *visit(il_param_list_c *symbol);

   818 //     void *visit(il_param_assignment_c *symbol);

   819 //     void *visit(il_param_out_assignment_c *symbol);

   820 

   821 

   822 /*******************/

   823 /* B 2.2 Operators */

   824 /*******************/

   825 void *narrow_candidate_datatypes_c::narrow_binary_operator(const struct widen_entry widen_table[], symbol_c *symbol, bool *deprecated_operation) {

   826 	symbol_c *prev_instruction_type, *operand_type;

   827 	int count = 0;

   828 

   829 	if (NULL == symbol->datatype)

   830 		/* next IL instructions were unable to determine the datatype this instruction should produce */

   831 		return NULL;

   832 

   833         if (NULL != deprecated_operation)

   834 		*deprecated_operation = false;

   835 

   836 	/* NOTE 1: the il_operand __may__ be pointing to a parenthesized list of IL instructions. 

   837 	 * e.g.  LD 33

   838 	 *       AND ( 45

   839 	 *            OR 56

   840 	 *            )

   841 	 *       When we handle the first 'AND' IL_operator, the il_operand will point to an simple_instr_list_c.

   842 	 *       In this case, when we call il_operand->accept(*this);, the prev_il_instruction pointer will be overwritten!

   843 	 *

   844 	 *       We must therefore set the prev_il_instruction->datatype = symbol->datatype;

   845 	 *       __before__ calling il_operand->accept(*this) !!

   846 	 *

   847 	 * NOTE 2: We do not need to call prev_il_instruction->accept(*this), as the object to which prev_il_instruction

   848 	 *         is pointing to will be later narrowed by the call from the for() loop of the instruction_list_c

   849 	 *         (or simple_instr_list_c), which iterates backwards.

   850 	 */

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

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

   853 			prev_instruction_type = fake_prev_il_instruction->candidate_datatypes[i];

   854 			operand_type = il_operand->candidate_datatypes[j];

   855 			if (is_widening_compatible(widen_table, prev_instruction_type, operand_type, symbol->datatype, deprecated_operation)) {

   856 				/* set the desired datatype of the previous il instruction */

   857 				set_datatype_in_prev_il_instructions(prev_instruction_type, fake_prev_il_instruction);

   858 				/* set the datatype for the operand */

   859 				il_operand->datatype = operand_type;

   860 				

   861 				count ++;

   862 			}

   863 		}

   864 	}

   865 // 	if (count > 1) ERROR; /* Since we also support SAFE data types, this assertion is not necessarily always tru! */

   866 	if (is_type_valid(symbol->datatype) && (count <= 0)) ERROR;

   867 

   868 	il_operand->accept(*this);

   869 	return NULL;

   870 }

   871 

   872 

   873 

   874 

   875 

   876 void *narrow_candidate_datatypes_c::handle_il_instruction(symbol_c *symbol) {

   877 	if (NULL == symbol->datatype)

   878 		/* next IL instructions were unable to determine the datatype this instruction should produce */

   879 		return NULL;

   880 	/* NOTE 1: the il_operand __may__ be pointing to a parenthesized list of IL instructions. 

   881 	 * e.g.  LD 33

   882 	 *       AND ( 45

   883 	 *            OR 56

   884 	 *            )

   885 	 *       When we handle the first 'AND' IL_operator, the il_operand will point to an simple_instr_list_c.

   886 	 *       In this case, when we call il_operand->accept(*this);, the prev_il_instruction pointer will be overwritten!

   887 	 *

   888 	 *       We must therefore set the prev_il_instruction->datatype = symbol->datatype;

   889 	 *       __before__ calling il_operand->accept(*this) !!

   890 	 *

   891 	 * NOTE 2: We do not need to call prev_il_instruction->accept(*this), as the object to which prev_il_instruction

   892 	 *         is pointing to will be later narrowed by the call from the for() loop of the instruction_list_c

   893 	 *         (or simple_instr_list_c), which iterates backwards.

   894 	 */

   895 	/* set the desired datatype of the previous il instruction */

   896 	set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction);

   897 	  

   898 	/* set the datatype for the operand */

   899 	il_operand->datatype = symbol->datatype;

   900 	il_operand->accept(*this);

   901 	return NULL;

   902 }

   903 

   904 

   905 

   906 

   907 void *narrow_candidate_datatypes_c::visit(LD_operator_c *symbol)   {

   908 	if (NULL == symbol->datatype)

   909 		/* next IL instructions were unable to determine the datatype this instruction should produce */

   910 		return NULL;

   911 	/* set the datatype for the operand */

   912 	il_operand->datatype = symbol->datatype;

   913 	il_operand->accept(*this);

   914 	return NULL;

   915 }

   916 

   917 

   918 void *narrow_candidate_datatypes_c::visit(LDN_operator_c *symbol)  {

   919 	if (NULL == symbol->datatype)

   920 		/* next IL instructions were unable to determine the datatype this instruction should produce */

   921 		return NULL;

   922 	/* set the datatype for the operand */

   923 	il_operand->datatype = symbol->datatype;

   924 	il_operand->accept(*this);

   925 	return NULL;

   926 }

   927 

   928 void *narrow_candidate_datatypes_c::visit(ST_operator_c *symbol) {

   929 	if (symbol->candidate_datatypes.size() != 1)

   930 		return NULL;

   931 	symbol->datatype = symbol->candidate_datatypes[0];

   932 	/* set the datatype for the operand */

   933 	il_operand->datatype = symbol->datatype;

   934 	il_operand->accept(*this);

   935 	/* set the desired datatype of the previous il instruction */

   936 	set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction);

   937 	return NULL;

   938 }

   939 

   940 void *narrow_candidate_datatypes_c::visit(STN_operator_c *symbol) {

   941 	if (symbol->candidate_datatypes.size() != 1)

   942 		return NULL;

   943 	symbol->datatype = symbol->candidate_datatypes[0];

   944 	/* set the datatype for the operand */

   945 	il_operand->datatype = symbol->datatype;

   946 	il_operand->accept(*this);

   947 	/* set the desired datatype of the previous il instruction */

   948 	set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction);

   949 	return NULL;

   950 }

   951 

   952 void *narrow_candidate_datatypes_c::visit(NOT_operator_c *symbol) {

   953 	/* NOTE: the standard allows syntax in which the NOT operator is followed by an optional <il_operand>

   954 	 *              NOT [<il_operand>]

   955 	 *       However, it does not define the semantic of the NOT operation when the <il_operand> is specified.

   956 	 *       We therefore consider it an error if an il_operand is specified!

   957 	 */

   958 	/* We do not change the data type, we simply invert the bits in bit types! */

   959 	/* So, we set the desired datatype of the previous il instruction */

   960 	set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction);

   961 	return NULL;

   962 }

   963 

   964 void *narrow_candidate_datatypes_c::visit(S_operator_c *symbol)  {

   965   /* TODO: what if this is a FB call? */

   966 	return handle_il_instruction(symbol);

   967 }

   968 void *narrow_candidate_datatypes_c::visit(R_operator_c *symbol)  {

   969   /* TODO: what if this is a FB call? */

   970 	return handle_il_instruction(symbol);

   971 }

   972 

   973 

   974 void *narrow_candidate_datatypes_c::visit(  S1_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "S1",  symbol->called_fb_declaration);}

   975 void *narrow_candidate_datatypes_c::visit(  R1_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "R1",  symbol->called_fb_declaration);}

   976 void *narrow_candidate_datatypes_c::visit( CLK_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "CLK", symbol->called_fb_declaration);}

   977 void *narrow_candidate_datatypes_c::visit(  CU_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "CU",  symbol->called_fb_declaration);}

   978 void *narrow_candidate_datatypes_c::visit(  CD_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "CD",  symbol->called_fb_declaration);}

   979 void *narrow_candidate_datatypes_c::visit(  PV_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "PV",  symbol->called_fb_declaration);}

   980 void *narrow_candidate_datatypes_c::visit(  IN_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "IN",  symbol->called_fb_declaration);}

   981 void *narrow_candidate_datatypes_c::visit(  PT_operator_c *symbol)  {return narrow_implicit_il_fb_call(symbol, "PT",  symbol->called_fb_declaration);}

   982 

   983 void *narrow_candidate_datatypes_c::visit( AND_operator_c *symbol)  {return narrow_binary_operator(widen_AND_table, symbol);}

   984 void *narrow_candidate_datatypes_c::visit(  OR_operator_c *symbol)  {return narrow_binary_operator( widen_OR_table, symbol);}

   985 void *narrow_candidate_datatypes_c::visit( XOR_operator_c *symbol)  {return narrow_binary_operator(widen_XOR_table, symbol);}

   986 void *narrow_candidate_datatypes_c::visit(ANDN_operator_c *symbol)  {return narrow_binary_operator(widen_AND_table, symbol);}

   987 void *narrow_candidate_datatypes_c::visit( ORN_operator_c *symbol)  {return narrow_binary_operator( widen_OR_table, symbol);}

   988 void *narrow_candidate_datatypes_c::visit(XORN_operator_c *symbol)  {return narrow_binary_operator(widen_XOR_table, symbol);}

   989 void *narrow_candidate_datatypes_c::visit( ADD_operator_c *symbol)  {return narrow_binary_operator(widen_ADD_table, symbol, &(symbol->deprecated_operation));}

   990 void *narrow_candidate_datatypes_c::visit( SUB_operator_c *symbol)  {return narrow_binary_operator(widen_SUB_table, symbol, &(symbol->deprecated_operation));}

   991 void *narrow_candidate_datatypes_c::visit( MUL_operator_c *symbol)  {return narrow_binary_operator(widen_MUL_table, symbol, &(symbol->deprecated_operation));}

   992 void *narrow_candidate_datatypes_c::visit( DIV_operator_c *symbol)  {return narrow_binary_operator(widen_DIV_table, symbol, &(symbol->deprecated_operation));}

   993 void *narrow_candidate_datatypes_c::visit( MOD_operator_c *symbol)  {return narrow_binary_operator(widen_MOD_table, symbol);}

   994 void *narrow_candidate_datatypes_c::visit(  GT_operator_c *symbol)  {return narrow_binary_operator(widen_CMP_table, symbol);}

   995 void *narrow_candidate_datatypes_c::visit(  GE_operator_c *symbol)  {return narrow_binary_operator(widen_CMP_table, symbol);}

   996 void *narrow_candidate_datatypes_c::visit(  EQ_operator_c *symbol)  {return narrow_binary_operator(widen_CMP_table, symbol);}

   997 void *narrow_candidate_datatypes_c::visit(  LT_operator_c *symbol)  {return narrow_binary_operator(widen_CMP_table, symbol);}

   998 void *narrow_candidate_datatypes_c::visit(  LE_operator_c *symbol)  {return narrow_binary_operator(widen_CMP_table, symbol);}

   999 void *narrow_candidate_datatypes_c::visit(  NE_operator_c *symbol)  {return narrow_binary_operator(widen_CMP_table, symbol);}

  1000 

  1001 

  1002 

  1003 

  1004 void *narrow_candidate_datatypes_c::narrow_conditional_flow_control_IL_instruction(symbol_c *symbol) {

  1005 	/* if the next IL instructions needs us to provide a datatype other than a bool, 

  1006 	 * then we have an internal compiler error - most likely in fill_candidate_datatypes_c 

  1007 	 */

  1008 	if ((NULL != symbol->datatype) && (!is_ANY_BOOL_compatible(symbol->datatype))) ERROR;

  1009 	if (symbol->candidate_datatypes.size() > 1) ERROR;

  1010 

  1011 	/* NOTE: If there is no IL instruction following this CALC, CALCN, JMPC, JMPC, ..., instruction,

  1012 	 *       we must still provide a bool_type_name_c datatype (if possible, i.e. if it exists in the candidate datatype list).

  1013 	 *       If it is not possible, we set it to NULL

  1014 	 */

  1015 	if (symbol->candidate_datatypes.size() == 0)    symbol->datatype = NULL;

  1016 	else    symbol->datatype = symbol->candidate_datatypes[0]; /* i.e. a bool_type_name_c! */

  1017 	if ((NULL != symbol->datatype) && (!is_ANY_BOOL_compatible(symbol->datatype))) ERROR;

  1018 

  1019 	/* set the required datatype of the previous IL instruction, i.e. a bool_type_name_c! */

  1020 	set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction);

  1021 	return NULL;

  1022 }

  1023 

  1024 

  1025 // SYM_REF0(CAL_operator_c)

  1026 // SYM_REF0(CALC_operator_c)

  1027 // SYM_REF0(CALCN_operator_c)

  1028 /* called from visit(il_fb_call_c *) {symbol->il_call_operator->accpet(*this)} */

  1029 /* NOTE: The CAL, JMP and RET instructions simply set the desired datatype of the previous il instruction since they do not change the value in the current/default IL variable */

  1030 /* called from il_fb_call_c (symbol->il_call_operator->accpet(*this) ) */

  1031 void *narrow_candidate_datatypes_c::visit(  CAL_operator_c *symbol) {set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction); return NULL;}

  1032 void *narrow_candidate_datatypes_c::visit(  RET_operator_c *symbol) {set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction); return NULL;}

  1033 void *narrow_candidate_datatypes_c::visit(  JMP_operator_c *symbol) {set_datatype_in_prev_il_instructions(symbol->datatype, fake_prev_il_instruction); return NULL;}

  1034 void *narrow_candidate_datatypes_c::visit( CALC_operator_c *symbol) {return narrow_conditional_flow_control_IL_instruction(symbol);}

  1035 void *narrow_candidate_datatypes_c::visit(CALCN_operator_c *symbol) {return narrow_conditional_flow_control_IL_instruction(symbol);}

  1036 void *narrow_candidate_datatypes_c::visit( RETC_operator_c *symbol) {return narrow_conditional_flow_control_IL_instruction(symbol);}

  1037 void *narrow_candidate_datatypes_c::visit(RETCN_operator_c *symbol) {return narrow_conditional_flow_control_IL_instruction(symbol);}

  1038 void *narrow_candidate_datatypes_c::visit( JMPC_operator_c *symbol) {return narrow_conditional_flow_control_IL_instruction(symbol);}

  1039 void *narrow_candidate_datatypes_c::visit(JMPCN_operator_c *symbol) {return narrow_conditional_flow_control_IL_instruction(symbol);}

  1040 

  1041 /* Symbol class handled together with function call checks */

  1042 // void *visit(il_assign_operator_c *symbol, variable_name);

  1043 /* Symbol class handled together with function call checks */

  1044 // void *visit(il_assign_operator_c *symbol, option, variable_name);

  1045 

  1046 

  1047 /***************************************/

  1048 /* B.3 - Language ST (Structured Text) */

  1049 /***************************************/

  1050 /***********************/

  1051 /* B 3.1 - Expressions */

  1052 /***********************/

  1053 void *narrow_candidate_datatypes_c::narrow_binary_expression(const struct widen_entry widen_table[], symbol_c *symbol, symbol_c *l_expr, symbol_c *r_expr, bool *deprecated_operation) {

  1054 	symbol_c *l_type, *r_type;

  1055 	int count = 0;

  1056 

  1057         if (NULL != deprecated_operation)

  1058 		*deprecated_operation = false;

  1059 

  1060 	for(unsigned int i = 0; i < l_expr->candidate_datatypes.size(); i++) {

  1061 		for(unsigned int j = 0; j < r_expr->candidate_datatypes.size(); j++) {

  1062 			/* test widening compatibility */

  1063 			l_type = l_expr->candidate_datatypes[i];

  1064 			r_type = r_expr->candidate_datatypes[j];

  1065 			if (is_widening_compatible(widen_table, l_type, r_type, symbol->datatype, deprecated_operation)) {

  1066 				l_expr->datatype = l_type;

  1067 				r_expr->datatype = r_type;

  1068 				count ++;

  1069 			}

  1070 		}

  1071 	}

  1072 // 	if (count > 1) ERROR; /* Since we also support SAFE data types, this assertion is not necessarily always tru! */

  1073 	if (is_type_valid(symbol->datatype) && (count <= 0)) ERROR;

  1074 	

  1075 	l_expr->accept(*this);

  1076 	r_expr->accept(*this);

  1077 	return NULL;

  1078 }

  1079 

  1080 

  1081 

  1082 void *narrow_candidate_datatypes_c::visit(    or_expression_c *symbol) {return narrow_binary_expression( widen_OR_table, symbol, symbol->l_exp, symbol->r_exp);}

  1083 void *narrow_candidate_datatypes_c::visit(   xor_expression_c *symbol) {return narrow_binary_expression(widen_XOR_table, symbol, symbol->l_exp, symbol->r_exp);}

  1084 void *narrow_candidate_datatypes_c::visit(   and_expression_c *symbol) {return narrow_binary_expression(widen_AND_table, symbol, symbol->l_exp, symbol->r_exp);}

  1085 

  1086 void *narrow_candidate_datatypes_c::visit(   equ_expression_c *symbol) {return narrow_binary_expression(widen_CMP_table, symbol, symbol->l_exp, symbol->r_exp);}

  1087 void *narrow_candidate_datatypes_c::visit(notequ_expression_c *symbol) {return narrow_binary_expression(widen_CMP_table, symbol, symbol->l_exp, symbol->r_exp);}

  1088 void *narrow_candidate_datatypes_c::visit(    lt_expression_c *symbol) {return narrow_binary_expression(widen_CMP_table, symbol, symbol->l_exp, symbol->r_exp);}

  1089 void *narrow_candidate_datatypes_c::visit(    gt_expression_c *symbol) {return narrow_binary_expression(widen_CMP_table, symbol, symbol->l_exp, symbol->r_exp);}

  1090 void *narrow_candidate_datatypes_c::visit(    le_expression_c *symbol) {return narrow_binary_expression(widen_CMP_table, symbol, symbol->l_exp, symbol->r_exp);}

  1091 void *narrow_candidate_datatypes_c::visit(    ge_expression_c *symbol) {return narrow_binary_expression(widen_CMP_table, symbol, symbol->l_exp, symbol->r_exp);}

  1092 

  1093 void *narrow_candidate_datatypes_c::visit(   add_expression_c *symbol) {return narrow_binary_expression(widen_ADD_table, symbol, symbol->l_exp, symbol->r_exp, &symbol->deprecated_operation);}

  1094 void *narrow_candidate_datatypes_c::visit(   sub_expression_c *symbol) {return narrow_binary_expression(widen_SUB_table, symbol, symbol->l_exp, symbol->r_exp, &symbol->deprecated_operation);}

  1095 void *narrow_candidate_datatypes_c::visit(   mul_expression_c *symbol) {return narrow_binary_expression(widen_MUL_table, symbol, symbol->l_exp, symbol->r_exp, &symbol->deprecated_operation);}

  1096 void *narrow_candidate_datatypes_c::visit(   div_expression_c *symbol) {return narrow_binary_expression(widen_DIV_table, symbol, symbol->l_exp, symbol->r_exp, &symbol->deprecated_operation);}

  1097 void *narrow_candidate_datatypes_c::visit(   mod_expression_c *symbol) {return narrow_binary_expression(widen_MOD_table, symbol, symbol->l_exp, symbol->r_exp);}

  1098 void *narrow_candidate_datatypes_c::visit( power_expression_c *symbol) {return narrow_binary_expression(widen_EXPT_table,symbol, symbol->l_exp, symbol->r_exp);}

  1099 

  1100 

  1101 void *narrow_candidate_datatypes_c::visit(neg_expression_c *symbol) {

  1102 	symbol->exp->datatype = symbol->datatype;

  1103 	symbol->exp->accept(*this);

  1104 	return NULL;

  1105 }

  1106 

  1107 

  1108 void *narrow_candidate_datatypes_c::visit(not_expression_c *symbol) {

  1109 	symbol->exp->datatype = symbol->datatype;

  1110 	symbol->exp->accept(*this);

  1111 	return NULL;

  1112 }

  1113 

  1114 

  1115 

  1116 /* NOTE: The parameter 'called_function_declaration', 'extensible_param_count' and 'candidate_functions' are used to pass data between the stage 3 and stage 4. */

  1117 /*    formal_param_list -> may be NULL ! */

  1118 /* nonformal_param_list -> may be NULL ! */

  1119 // SYM_REF3(function_invocation_c, function_name, formal_param_list, nonformal_param_list, symbol_c *called_function_declaration; int extensible_param_count; std::vector <symbol_c *> candidate_functions;)

  1120 void *narrow_candidate_datatypes_c::visit(function_invocation_c *symbol) {

  1121 	generic_function_call_t fcall_param = {

  1122 		/* fcall_param.function_name               = */ symbol->function_name,

  1123 		/* fcall_param.nonformal_operand_list      = */ symbol->nonformal_param_list,

  1124 		/* fcall_param.formal_operand_list         = */ symbol->formal_param_list,

  1125 		/* enum {POU_FB, POU_function} POU_type    = */ generic_function_call_t::POU_function,

  1126 		/* fcall_param.candidate_functions         = */ symbol->candidate_functions,

  1127 		/* fcall_param.called_function_declaration = */ symbol->called_function_declaration,

  1128 		/* fcall_param.extensible_param_count      = */ symbol->extensible_param_count

  1129 	};

  1130   

  1131 	narrow_function_invocation(symbol, fcall_param);

  1132 	return NULL;

  1133 }

  1134 

  1135 /********************/