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

/*

    36

 *  Fill candidate list of data types for all symbols

    37

 */

    38

    39

#include "fill_candidate_datatypes.hh"

    40

#include "datatype_functions.hh"

    41

#include <typeinfo>

    42

#include <list>

    43

#include <string>

    44

#include <string.h>

    45

#include <strings.h>

    46

    47

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

    48

static int debug = 0;

    49

    50

fill_candidate_datatypes_c::fill_candidate_datatypes_c(symbol_c *ignore) {

    51

}

    52

    53

fill_candidate_datatypes_c::~fill_candidate_datatypes_c(void) {

    54

}

    55

    57

	int k;

    58

	/* find a widening table entry compatible */

    59

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

    61

                      return widen_table[k].result;

    62

	return NULL;

    63

}

    64

    65

    66

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

    67

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

    68

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

    75

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

    76

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

    77

    return false;

    78

    79

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

    80

  symbol->candidate_datatypes.push_back(datatype);

    81

  return true;

    82

}

    83

    84

    85

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

    86

  add_datatype_to_candidate_list(symbol, datatype1);

    87

  add_datatype_to_candidate_list(symbol, datatype2);

    88

  return true;

    89

}

    90

    91

    92

/* 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 */

    94

/*

    95

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

    96

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

    97

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

    98

 */

    99

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

   100

	symbol_c *call_param_value,  *param_datatype;

   101

	identifier_c *param_name;

   102

	function_param_iterator_c       fp_iterator(f_decl);

   103

	function_call_param_iterator_c fcp_iterator(f_call);

   104

	int extensible_parameter_highest_index = -1;

   105

	unsigned int i;

   106

   107

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

   108

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

   109

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

   110

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

   111

		 */

   112

		do {

   113

			param_name = fp_iterator.next();

   114

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

   115

			if(param_name == NULL) return false;

   116

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

   117

   118

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

   119

		/* Get the parameter type */

   120

		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 */

   123

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

   124

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

   125

	}

   126

	/* 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) {

   135

	symbol_c *call_param_value, *call_param_name, *param_datatype;

   136

	symbol_c *verify_duplicate_param;

   137

	identifier_c *param_name;

   138

	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;

   141

	identifier_c *extensible_parameter_name;

   142

	unsigned int i;

   143

	bool is_first_param = true;

   144

   145

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

   146

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

   147

		/* 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

/*

   218

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,

   221

                                                       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

   320

/* a helper function... */

   321

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

   322

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

   323

	 *       in the code.

   324

	 */

   325

	if (symbol == NULL) return NULL;

   326

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

   327

}

   328

   329

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

   330

/* B 1.2 - Constants */

   331

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

   332

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

   333

/* B 1.2.1 - Numeric Literals */

   334

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

   335

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

   336

   337

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

   338

	int calc_size;

   339

   340

	calc_size = sizeoftype(symbol);

   341

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

   342

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

   343

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

   344

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

   345

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

   346

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

   347

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

   348

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

   349

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

   350

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

   351

   352

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

   353

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

   354

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

   355

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

   356

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

   357

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

   358

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

   359

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

   360

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

   361

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

   362

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

   363

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

   364

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

   365

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

   366

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

   367

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

   368

	return NULL;

   369

}

   370

   371

   372

   373

   374

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

   375

	int calc_size;

   376

   377

	calc_size = sizeoftype(symbol);

   378

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

   379

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

   380

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

   381

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

   382

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

   383

	return NULL;

   384

}

   385

   386

   387

   388

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

   389

	handle_any_integer(symbol);

   390

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

   391

	return NULL;

   392

}

   393

   394

   395

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

   396

	int calc_size;

   397

   398

	calc_size = sizeoftype(symbol);

   399

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

   400

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

   401

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

   402

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

   403

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

   404

	return NULL;

   405

}

   406

   407

   408

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

   409

	int calc_size;

   410

   411

	calc_size = sizeoftype(symbol);

   412

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

   413

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

   414

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

   415

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

   416

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

   417

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

   418

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

   419

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

   420

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

   421

	return NULL;

   422

}

   423

   424

   425

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

   426

	handle_any_integer(symbol);

   427

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

   428

	return NULL;

   429

}

   430

   431

   432

   433

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

   434

	handle_any_integer(symbol);

   435

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

   436

	return NULL;

   437

}

   438

   439

   440

   441

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

   442

	handle_any_integer(symbol);

   443

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

   444

	return NULL;

   445

}

   446

   447

   448

// SYM_REF2(integer_literal_c, type, value)

   449

/*

   450

 * integer_literal:

   451

 *   integer_type_name '#' signed_integer

   452

 * | integer_type_name '#' binary_integer

   453

 * | integer_type_name '#' octal_integer

   454

 * | integer_type_name '#' hex_integer

   455

 */

   456

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

   457

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

   458

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

   459

		add_datatype_to_candidate_list(symbol, symbol->type);

   460

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

   461

	return NULL;

   462

}

   463

   464

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

   465

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

   466

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

   467

		add_datatype_to_candidate_list(symbol, symbol->type);

   468

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

   469

	return NULL;

   470

}

   471

   472

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

   473

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

   474

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

   475

		add_datatype_to_candidate_list(symbol, symbol->type);

   476

	return NULL;

   477

}

   478

   479

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

   480

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

   481

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

   482

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

   483

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

   484

		 */

   485

		add_datatype_to_candidate_list(symbol, symbol->type);

   486

	else {

   487

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

   488

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

   489

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

   490

	}

   491

	return NULL;

   492

}

   493

   494

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

   495

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

   496

	return NULL;

   497

}

   498

   499

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

   500