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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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    26

/*

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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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/*

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 *  Fill candidate list of data types for all symbols

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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;

    49

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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;

    63

}

    64

    65

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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. 

    71

   */

    72

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

    73

    return false;

    74

    75

  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;

    78

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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);

    81

  return true;

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}

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    84

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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;

    89

}

    90

    91

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

    93

/* 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;

   102

	function_param_iterator_c       fp_iterator(f_decl);

   103

	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.

   111

		 */

   112

		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;

   116

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

   117

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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());

   121

   122

		/* 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! */

   127

	return true;

   128

}

   129

   130

   131

   132

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

   133

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

   134

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);

   139

	function_call_param_iterator_c fcp_iterator(f_call);

   140

	int extensible_parameter_highest_index = -1;

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	identifier_c *extensible_parameter_name;

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	unsigned int i;

   143

	bool is_first_param = true;

   144

   145

	/* 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 */

   148

		call_param_value = fcp_iterator.get_current_value();

   149

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

   150

		if (NULL == call_param_value) ERROR;

   151

   152

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

   153

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

   154

   155

		/* Checking if there are duplicated parameter values */

   156

		verify_duplicate_param = fcp_iterator.search_f(call_param_name);

   157

		if(verify_duplicate_param != call_param_value)

   158

			return false;

   159

   160

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

   161

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

   162

   163

		/* Find the corresponding parameter in function declaration */

   164

		param_name = fp_iterator.search(call_param_name);

   165

		if(param_name == NULL) return false;

   166

		/* Get the parameter data type */

   167

		param_datatype = base_type(fp_iterator.param_type());

   168

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

   169

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

   170

   171

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

   172

		if          (function_call_param_iterator_c::assign_in  == call_param_dir) {

   173

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

   174

			    (function_param_iterator_c::direction_inout != param_dir))

   175

				return false;

   176

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

   177

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

   178

				return false;

   179

		} else ERROR;

   180

   181

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

   182

		if (search_in_candidate_datatype_list(param_datatype, call_param_types) < 0)

   183

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

   184

   185

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

   186

		if (is_first_param)

   187

			if (NULL != first_param_datatype)

   188

				*first_param_datatype = param_datatype;

   189

		is_first_param = false;

   190

	}

   191

	/* call is compatible! */

   192

	return true;

   193

}

   194

   195

   196

   197

   198

/* Handle a generic function call!

   199

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

   200

 * has already had all the candidate_datatype lists filled in!

   201

 *

   202

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

   203

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

   204

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

   205

 */

   206

/*

   207

typedef struct {

   208

  symbol_c *function_name,

   209

  symbol_c *nonformal_operand_list,

   210

  symbol_c *   formal_operand_list,

   211

   212

  std::vector <symbol_c *> &candidate_functions,  

   213

  symbol_c &*called_function_declaration,

   214

  int      &extensible_param_count

   215

} generic_function_call_t;

   216

*/

   217

/*

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

   219

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

   220

                                                       std::vector <symbol_c *> *candidate_datatypes,

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

   222

  */

   223

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

   224

	function_declaration_c *f_decl;

   225

	list_c *parameter_list;

   226

	list_c *parameter_candidate_datatypes;

   227

	symbol_c *returned_parameter_type;

   228

   229

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

   230

   231

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

   232

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

   233

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

   234

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

   235

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

   236

   237

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

   238

	 * to the candidate_datatype list of this function invocation. 

   239

	 *

   240

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

   241

	 * even if the parameters passed to it are invalid.

   242

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

   243

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

   244

	 * spurious error messages.

   245

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

   246

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

   247

	 * compilation is aborted in stage3 (in print_datatypes_error_c).

   248

	 */

   249

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

   250

		f_decl = function_symtable.get_value(lower);

   251

		returned_parameter_type = base_type(f_decl->type_name);

   252

		if (add_datatype_to_candidate_list(fcall, returned_parameter_type))

   253

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

   254

			fcall_data.candidate_functions.push_back(f_decl);

   255

   256

	}

   257

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

   258

		bool compatible = false;

   259

   260

		f_decl = function_symtable.get_value(lower);

   261

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

   262

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

   263

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

   264

		if (compatible) {

   265

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

   266

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

   267

			 */

   268

			returned_parameter_type = base_type(f_decl->type_name);		

   269

			if (add_datatype_to_candidate_list(fcall, returned_parameter_type))

   270

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

   271

				fcall_data.candidate_functions.push_back(f_decl);

   272

		}

   273

	}

   274

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

   275

	return;

   276

}

   277

   278

   279

/* handle implicit FB call in IL.

   280

 * e.g.  CLK ton_var

   281

 *        CU counter_var

   282

 */

   283

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

   284

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

   285

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

   286

	if (NULL == fb_type_id) ERROR;

   287

   288

	function_block_declaration_c *fb_decl = function_block_type_symtable.find_value(fb_type_id);

   289

	if (function_block_type_symtable.end_value() == fb_decl)

   290

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

   291

		 * this is a semantic error.

   292

		 */

   293

		fb_decl = NULL;

   294

   295

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

   296

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

   297

	 * more informative error messages!

   298

	 */

   299

	called_fb_declaration = fb_decl;

   300

   301

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

   302

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

   303

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

   304

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

   305

	 * that are compatible to the FB call. 

   306

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

   307

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

   308

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

   309

	 * correct.

   310

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

   311

	 * here).

   312

	 */

   313

	if (NULL != prev_il_instruction)

   314

		il_instruction->candidate_datatypes = prev_il_instruction->candidate_datatypes; 

   315

   316

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

   317

}

   318

   319

   347

/* a helper function... */

   348

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

   349

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

   350

	 *       in the code.

   351

	 */

   352

	if (symbol == NULL) return NULL;

   353

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

   354

}

   355

   356

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

   357

/* B 1.2 - Constants */

   358

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

   359

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

   360

/* B 1.2.1 - Numeric Literals */

   361

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

   362

#define sizeoftype(symbol) get_sizeof_datatype_c::getsize(symbol)

   363

   364

void *fill_candidate_datatypes_c::handle_any_integer(symbol_c *symbol) {

   365

	int calc_size;

   366

   367

	calc_size = sizeoftype(symbol);

   368

	if (calc_size <= sizeoftype(&search_constant_type_c::bool_type_name))

   369

	        add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::bool_type_name, &search_constant_type_c::safebool_type_name);

   370

	if (calc_size <= sizeoftype(&search_constant_type_c::byte_type_name))

   371

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::byte_type_name, &search_constant_type_c::safebyte_type_name);

   372

	if (calc_size <= sizeoftype(&search_constant_type_c::word_type_name))

   373

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::word_type_name, &search_constant_type_c::safeword_type_name);

   374

	if (calc_size <= sizeoftype(&search_constant_type_c::dword_type_name))

   375

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::dword_type_name, &search_constant_type_c::safedword_type_name);

   376

	if (calc_size <= sizeoftype(&search_constant_type_c::lword_type_name))

   377

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::lword_type_name, &search_constant_type_c::safelword_type_name);

   378

   379

	if (calc_size < sizeoftype(&search_constant_type_c::sint_type_name))

   380

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::sint_type_name, &search_constant_type_c::safesint_type_name);

   381

	if (calc_size < sizeoftype(&search_constant_type_c::int_type_name))

   382

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::int_type_name, &search_constant_type_c::safeint_type_name);

   383

	if (calc_size < sizeoftype(&search_constant_type_c::dint_type_name))

   384

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::dint_type_name, &search_constant_type_c::safedint_type_name);

   385

	if (calc_size < sizeoftype(&search_constant_type_c::lint_type_name))

   386

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::lint_type_name, &search_constant_type_c::safelint_type_name);

   387

	if (calc_size <= sizeoftype(&search_constant_type_c::usint_type_name))

   388

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::usint_type_name, &search_constant_type_c::safeusint_type_name);

   389

	if (calc_size <= sizeoftype(&search_constant_type_c::uint_type_name))

   390

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::uint_type_name, &search_constant_type_c::safeuint_type_name);

   391

	if (calc_size <= sizeoftype(&search_constant_type_c::udint_type_name))

   392

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::udint_type_name, &search_constant_type_c::safeudint_type_name);

   393

	if (calc_size <= sizeoftype(&search_constant_type_c::ulint_type_name))

   394

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::ulint_type_name, &search_constant_type_c::safeulint_type_name);

   397

	return NULL;

   398

}

   399

   400

   401

   402

   403

void *fill_candidate_datatypes_c::visit(real_c *symbol) {

   404

	int calc_size;

   405

   406

	calc_size = sizeoftype(symbol);

   407

	if (calc_size <= sizeoftype(&search_constant_type_c::real_type_name))

   408

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::real_type_name,  &search_constant_type_c::safereal_type_name);

   409

	if (calc_size <= sizeoftype(&search_constant_type_c::lreal_type_name))

   410

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::lreal_type_name, &search_constant_type_c::safelreal_type_name);

   411

	if (debug) std::cout << "ANY_REAL [" << symbol->candidate_datatypes.size() << "]" << std::endl;

   412

	return NULL;

   413

}

   414

   415

   416

void *fill_candidate_datatypes_c::visit(neg_real_c *symbol) {

   417

	int calc_size;

   418

   419

	calc_size = sizeoftype(symbol);

   420

	if (calc_size <= sizeoftype(&search_constant_type_c::real_type_name))

   421

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::real_type_name, &search_constant_type_c::safereal_type_name);

   422

	if (calc_size <= sizeoftype(&search_constant_type_c::lreal_type_name))

   423

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::lreal_type_name, &search_constant_type_c::safelreal_type_name);

   424

	if (debug) std::cout << "neg ANY_REAL [" << symbol->candidate_datatypes.size() << "]" << std::endl;

   425

	return NULL;

   426

}

   427

   428

   429

void *fill_candidate_datatypes_c::visit(neg_integer_c *symbol) {

   430

	int calc_size;

   431

   432

	calc_size = sizeoftype(symbol);

   433

	if (calc_size <= sizeoftype(&search_constant_type_c::int_type_name))

   434

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::int_type_name, &search_constant_type_c::safeint_type_name);

   435

	if (calc_size <= sizeoftype(&search_constant_type_c::sint_type_name))

   436

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::sint_type_name, &search_constant_type_c::safesint_type_name);

   437

	if (calc_size <= sizeoftype(&search_constant_type_c::dint_type_name))

   438

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::dint_type_name, &search_constant_type_c::safedint_type_name);

   439

	if (calc_size <= sizeoftype(&search_constant_type_c::lint_type_name))

   440

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::lint_type_name, &search_constant_type_c::safelint_type_name);

   441

	if (debug) std::cout << "neg ANY_INT [" << symbol->candidate_datatypes.size() << "]" << std::endl;

   442

	return NULL;

   443

}

   444

   445

   450

   451

   452

// SYM_REF2(integer_literal_c, type, value)

   453

/*

   454

 * integer_literal:

   455

 *   integer_type_name '#' signed_integer

   456

 * | integer_type_name '#' binary_integer

   457

 * | integer_type_name '#' octal_integer

   458

 * | integer_type_name '#' hex_integer

   459

 */

   460

void *fill_candidate_datatypes_c::visit(integer_literal_c *symbol) {

   461

	symbol->value->accept(*this);

   462

	if (search_in_candidate_datatype_list(symbol->type, symbol->value->candidate_datatypes) >= 0)

   463

		add_datatype_to_candidate_list(symbol, symbol->type);

   464

	if (debug) std::cout << "INT_LITERAL [" << symbol->candidate_datatypes.size() << "]\n";

   465

	return NULL;

   466

}

   467

   468

void *fill_candidate_datatypes_c::visit(real_literal_c *symbol) {

   469

	symbol->value->accept(*this);

   470

	if (search_in_candidate_datatype_list(symbol->type, symbol->value->candidate_datatypes) >= 0)

   471

		add_datatype_to_candidate_list(symbol, symbol->type);

   472

	if (debug) std::cout << "REAL_LITERAL [" << symbol->candidate_datatypes.size() << "]\n";

   473

	return NULL;

   474

}

   475

   476

void *fill_candidate_datatypes_c::visit(bit_string_literal_c *symbol) {

   477

	symbol->value->accept(*this);

   478

	if (search_in_candidate_datatype_list(symbol->type, symbol->value->candidate_datatypes) >= 0)

   479

		add_datatype_to_candidate_list(symbol, symbol->type);

   480

	return NULL;

   481

}

   482

   483

void *fill_candidate_datatypes_c::visit(boolean_literal_c *symbol) {

   484

 	symbol->value->accept(*this);

   485

 	if (search_in_candidate_datatype_list(symbol->type, symbol->value->candidate_datatypes) >= 0)

   486

		/* if an explicit datat type has been provided (e.g. SAFEBOOL#true), check whether

   487

		 * the possible datatypes of the value is consistent with the desired type.

   488

		 */

   489

		add_datatype_to_candidate_list(symbol, symbol->type);

   490

	else {

   491

		/* Then only a literal TRUE or FALSE was given! */

   492

		/* In this case, symbol->type will be NULL!     */

   493

		add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::bool_type_name, &search_constant_type_c::safebool_type_name);

   494

	}

   495

	return NULL;

   496

}

   497

   498

void *fill_candidate_datatypes_c::visit(boolean_true_c *symbol) {

   499

	add_2datatypes_to_candidate_list(symbol, &search_constant_type_c::bool_type_name, &search_constant_type_c::safebool_type_name);