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

	search_varfb_instance_type = NULL;

    70

	fake_prev_il_instruction = NULL;

    71

	il_operand = NULL;

    72

}

    73

    74

narrow_candidate_datatypes_c::~narrow_candidate_datatypes_c(void) {

    75

}

    76

    77

    78

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

    79

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

    80

    81

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

    82

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

    83

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

    84

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

    85

	 */

    86

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

    87

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

    88

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

    89

    90

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

    91

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

    92

	else {

    93

		if (NULL == symbol->datatype)   

    94

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

    95

			symbol->datatype = datatype; 

    96

		else {

    97

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

    98

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

    99

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

   100

// 			else 

   101

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

   102

		}

   103

	}

   104

}

   105

   106

   107

   108

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

   109

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

   110

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

   111

	if (NULL == symbol) ERROR;

   112

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

   113

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

   114

}

   115

   116

   117

   118

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) {

   119

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

   120

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

   121

	 */

   122

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

   123

		return false;

   124

   125

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

   126

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

   127

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

   128

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

   129

			if (NULL != deprecated_status)

   130

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

   131

			return true;

   132

		}

   133

	}

   134

	return false;

   135

}

   136

   137

/*

   138

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

   139

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

   140

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

   141

 */

   142

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

   143

	symbol_c *call_param_value,  *param_type;

   144

	identifier_c *param_name;

   145

	function_param_iterator_c       fp_iterator(f_decl);

   146

	function_call_param_iterator_c fcp_iterator(f_call);

   147

	int extensible_parameter_highest_index = -1;

   148

	unsigned int i;

   149

   150

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

   151

   152

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

   153

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

   154

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

   155

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

   156

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

   157

		 */

   158

		do {

   159

			param_name = fp_iterator.next();

   160

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

   161

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

   162

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

   163

			 * for that code too!

   164

			 */

   165

			if(param_name == NULL) break;

   166

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

   167

   168

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

   169

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

   170

		 * we may be setting this to NULL!

   171

		 */

   172

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

   173

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

   174

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

   175

   176

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

   177

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

   178

		 *       the call 

   179

		 *       call_param_value->accept(*this);

   180

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

   181

		 */

   182

		set_datatype(desired_datatype, call_param_value);

   183

		call_param_value->accept(*this);

   184

   185

		if (NULL != param_name) 

   186

			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   187

				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   188

	}

   189

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

   190

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

   191

	 * of the function call itself!

   192

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

   193

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

   194

	 * output code.

   195

	 */

   196

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

   197

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

   198

}

   199

   200

   201

   202

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

   203

	symbol_c *call_param_value, *call_param_name, *param_type;

   204

	symbol_c *verify_duplicate_param;

   205

	identifier_c *param_name;

   206

	function_param_iterator_c       fp_iterator(f_decl);

   207

	function_call_param_iterator_c fcp_iterator(f_call);

   208

	int extensible_parameter_highest_index = -1;

   209

	identifier_c *extensible_parameter_name;

   210

	unsigned int i;

   211

   212

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

   213

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

   214

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

   215

   216

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

   217

		call_param_value = fcp_iterator.get_current_value();

   218

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

   219

		if (NULL == call_param_value) ERROR;

   220

   221

		/* Find the corresponding parameter in function declaration */

   222

		param_name = fp_iterator.search(call_param_name);

   223

   224

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

   225

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

   226

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

   227

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

   228

		 */

   229

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

   230

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

   231

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

   232

   233

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

   234

		set_datatype(desired_datatype, call_param_value);

   235

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

   236

		call_param_value->accept(*this);

   237

   238

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

   239

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

   240

		if (NULL != param_name) 

   241

			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   242

				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   243

	}

   244

	/* call is compatible! */

   245

   246

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

   247

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

   248

	 * of the function call itself!

   249

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

   250

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

   251

	 * output code.

   252

	 */

   253

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

   254

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

   255

}

   256

   257

   258

/*

   259

typedef struct {

   260

  symbol_c *function_name,

   261

  symbol_c *nonformal_operand_list,

   262

  symbol_c *   formal_operand_list,

   263

   264

  std::vector <symbol_c *> &candidate_functions,  

   265

  symbol_c &*called_function_declaration,

   266

  int      &extensible_param_count

   267

} generic_function_call_t;

   268

*/

   269

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

   270

	/* set the called_function_declaration. */

   271

	fcall_data.called_function_declaration = NULL;

   272

   273

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

   274

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

   275

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

   276

			fcall_data.called_function_declaration = fcall_data.candidate_functions[i];

   277

			break;

   278

		}

   279

	}

   280

   281

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

   282

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

   283

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

   284

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

   285

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

   286

	 *       invocation.

   287

	 */

   288

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

   289

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

   290

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

   291

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

   292

		 * function invocation.

   293

		 */

   294

		fcall_data.called_function_declaration = fcall_data.candidate_functions[0];

   295

	}

   296

   297

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

   298

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

   299

	 * We simply give up!

   300

	 */

   301

	if (NULL == fcall_data.called_function_declaration)

   302

		return;

   303

   304

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

   305

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

   306

   307

	return;

   308

}

   309

   310

   311

   312

   313

/* narrow implicit FB call in IL.

   314

 * e.g.  CLK ton_var

   315

 *        CU counter_var

   316

 *

   317

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

   318

 * the visit(il_fb_call_c *) method handle it!

   319

 */

   320

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

   321

   322

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

   323

	if (NULL != il_operand) {

   324

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

   325

		set_datatype(called_fb_declaration, il_operand);

   326

		il_operand->accept(*this);

   327

	}

   328

	symbol_c *fb_decl = il_operand->datatype;

   329

   330

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

   331

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

   332

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

   333

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

   334

		 */

   335

		return NULL;

   336

	}

   337

   338

	if (NULL == fb_decl) {

   339

		/* the il_operand is a not FB instance */

   340

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

   341

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

   342

		set_datatype_in_prev_il_instructions(il_instruction->datatype, fake_prev_il_instruction);

   343

		return NULL;

   344

	}

   345

   346

   347

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

   348

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

   349

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

   350

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

   351

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

   352

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

   353

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

   354

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

   355

	 */

   356

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

   357

   358

	identifier_c variable_name(param_name);

   359

	// SYM_REF1(il_assign_operator_c, variable_name)

   360

	il_assign_operator_c il_assign_operator(&variable_name);  

   361

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

   362

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

   363

	il_param_list_c il_param_list;

   364

	il_param_list.add_element(&il_param_assignment);

   365

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

   366

	CAL_operator_c CAL_operator;

   367

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

   368

   369

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

   370

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

   371

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

   372

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

   373

	 *

   374

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

   375

	 * correctly set up the il_fb_call.datatype variable!

   376

	 */

   377

	il_fb_call.called_fb_declaration = called_fb_declaration;

   378

	il_fb_call.accept(*this);

   379

   380

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

   381

	/* NOTE:

   382

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

   383

	 * is actually the prev_il_instruction.

   384

	 * 

   385

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

   386

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

   387

	 *

   388

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

   389

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

   390

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

   391

	 * and we set it to invalid_type_name.

   392

	 *

   393

	 * However, we only do that if:

   394

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

   395

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

   396

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

   397

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

   398

	 *     FB call must be left unchanged!

   399

	 */

   400

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

   401

		set_datatype_in_prev_il_instructions(param_value.datatype, fake_prev_il_instruction);

   402

	} else {

   403

		set_datatype_in_prev_il_instructions(&search_constant_type_c::invalid_type_name, fake_prev_il_instruction);

   404

	}

   405

	return NULL;

   406

}

   407

   408

   409

/* a helper function... */

   410

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

   411

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

   412

	 *       in the code.

   413

	 */

   414

	if (symbol == NULL) return NULL;

   415

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

   416

}

   417

   418

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

   419

/* B 1.2 - Constants */

   420

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

   421

   422

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

   423

/* B 1.3 - Data types */

   424

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

   425

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

   426

/* B 1.3.3 - Derived data types */

   427

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

   428

/* simple_specification ASSIGN constant */

   429

// SYM_REF2(simple_spec_init_c, simple_specification, constant)

   430

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

   431

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

   432

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

   433

   434

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

   435

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

   436

   437

	if (NULL != symbol->constant) {

   438

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

   439

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

   440

	}

   441

	return NULL;

   442

}

   443

   444

   445

   446

/*  signed_integer DOTDOT signed_integer */

   447

// SYM_REF2(subrange_c, lower_limit, upper_limit)

   448

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

   449

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

   450

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

   451

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

   452

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

   453

	return NULL;

   454

}

   455

   456

   457

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

   458

/* B 1.4 - Variables */

   459

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

   460

   461

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

   462

/* B 1.4.1 - Directly Represented Variables */

   463

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

   464

   465

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

   466

/* B 1.4.2 - Multi-element variables */

   467

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

   468

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

   469

// SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   470

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

   471

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

   472

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

   473

	return NULL;

   474

}

   475

   476

   477

/* subscript_list ',' subscript */

   478

// SYM_LIST(subscript_list_c)

   479

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

   480

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

   481

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

   482

			if (get_datatype_info_c::is_ANY_INT(symbol->elements[i]->candidate_datatypes[k]))

   483

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

   484

		}

   485

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

   486

	}

   487

	return NULL;  

   488

}

   489

   490

   491

   492

   493

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

   494

/* B 1.4.3 - Declaration & Initialisation */

   495

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

   496

   497

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

   498

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

   499

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

   500

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

   501

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