1

/*

     2

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

     3

 *

     4

 *  Copyright (C) 2003-2012  Mario de Sousa (msousa@fe.up.pt)

     5

 *  Copyright (C) 2007-2011  Laurent Bessard and Edouard Tisserant

     6

 *

     7

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

     8

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

     9

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

    10

 *  (at your option) any later version.

    11

 *

    12

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

    13

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

    14

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    15

 *  GNU General Public License for more details.

    16

 *

    17

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

    18

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

    19

 *

    20

 *

    21

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

    22

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

    23

 */

    24

    25

/*

    26

 * An IEC 61131-3 compiler.

    27

 *

    28

 * Based on the

    29

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

    30

 *

    31

 */

    32

    33

/* Determine the data type of a variable.

    34

 * The variable may be a simple variable, a function block instance, a

    35

 * struture element within a data structured type (a struct or a fb), or

    36

 * an array element.

    37

 * A mixture of array element of a structure element of a structure element

    38

 * of a .... is also suported!

    39

 *

    40

 *  example:

    41

 *    window.points[1].coordinate.x

    42

 *    window.points[1].colour

    43

 *    etc... ARE ALLOWED!

    44

 *

    45

 * This class must be passed the scope within which the

    46

 * variable was declared, and the variable name...

    47

 *

    48

 *

    49

 *

    50

 *

    51

 *

    52

 * This class has several members, depending on the exact data the caller

    53

 * is looking for...

    54

 *

    55

 *    - item i: we can get either the name of the data type(A),

    56

 *              or it's declaration (B)

    57

 *             (notice however that some variables belong to a data type that does

    58

 *              not have a name, only a declaration as in

    59

 *              VAR a: ARRAY [1..3] of INT; END_VAR

    60

 *             )

    61

 *    - item ii: we can get either the direct data type (1), 

    62

 *               or the base type (2)

    63

 * 

    64

 *   By direct type, I mean the data type of the variable. By base type, I 

    65

 * mean the data type on which the direct type is based on. For example, in 

    66

 * a subrange on INT, the direct type is the subrange itself, while the 

    67

 * base type is INT.

    68

 * e.g.

    69

 *   This means that if we find that the variable is of type MY_INT,

    70

 *   which was previously declared to be

    71

 *   TYPE MY_INT: INT := 9;

    72

 *   option (1) will return MY_INT

    73

 *   option (2) will return INT

    74

 * 

    75

 *

    76

 * Member functions:

    77

 * ================

    78

 *   get_basetype_id()    ---> returns 2A   (implemented, although currently it is not needed! )

    79

 *   get_basetype_decl()  ---> returns 2B 

    80

 *   get_type_id()        ---> returns 1A

    81

 * 

    82

 *   Since we haven't yet needed it, we don't yet implement

    83

 *   get_type_decl()      ---> returns 1B 

    84

 */ 

    85

    86

    87

    88

#include "absyntax_utils.hh"

    89

    90

    91

void search_varfb_instance_type_c::init(void) {

    92

  this->current_type_id        = NULL;

    93

  this->current_basetype_id    = NULL;

    94

  this->current_basetype_decl  = NULL;

    95

  this->current_field_selector = NULL;

    96

  this->is_complex = false;

    97

}

    98

    99

   100

search_varfb_instance_type_c::search_varfb_instance_type_c(symbol_c *search_scope): search_var_instance_decl(search_scope) {

   101

  this->init();

   102

}

   103

   104

   105

/* We expect to be passed a symbolic_variable_c */

   106

symbol_c *search_varfb_instance_type_c::get_type_id(symbol_c *variable_name) {

   107

  this->init();

   108

  variable_name->accept(*this);

   109

  return current_type_id;

   110

}

   111

   112

   113

symbol_c *search_varfb_instance_type_c::get_basetype_id(symbol_c *variable_name) {

   114

  this->init();

   115

  variable_name->accept(*this);

   116

  return current_basetype_id;

   117

}

   118

   119

   120

symbol_c *search_varfb_instance_type_c::get_basetype_decl(symbol_c *variable_name) {

   121

  this->init();

   122

  variable_name->accept(*this);

   123

  return current_basetype_decl;

   124

}  

   125

   126

   127

   128

bool search_varfb_instance_type_c::type_is_complex(symbol_c *variable_name) {

   129

  this->init();

   130

  variable_name->accept(*this);

   131

  return this->is_complex;

   132

}

   133

   134

   135

   136

   137

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

   138

/* B.1 - Common elements */

   139

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

   140

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

   141

/* B 1.1 - Letters, digits and identifiers */

   142

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

   143

// SYM_TOKEN(identifier_c)

   144

void *search_varfb_instance_type_c::visit(identifier_c *variable_name) {

   145

  /* symbol should be a variable name!! */

   146

  /* Note: although the method is called get_decl(), it is getting the declaration of the variable, which for us is the type_id of that variable! */

   147

  current_type_id       = search_var_instance_decl.get_decl (variable_name);

   148

  current_basetype_decl = search_base_type.get_basetype_decl(current_type_id);

   149

  current_basetype_id   = search_base_type.get_basetype_id  (current_type_id);

   150

   151

  /* What if the variable has not been declared?  Then this should not be a compiler error! 

   152

   * However, currently stage 2 of the compiler already detects when variables have not been delcared,

   153

   * so if the variable's declaration is not found, then that means that we have an internal compiler error!

   154

   */

   155

  if (NULL == current_type_id) ERROR; 

   156

   157

  return NULL;

   158

}

   159

   160

   161

   162

   163

   164

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

   165

/* B 1.3.3 - Derived data types */

   166

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

   167

/*  identifier ':' array_spec_init */

   168

/* NOTE: I don't think this will ever get called, since in the visit method for array_variable_c

   169

 * we use the basetype_decl for recursively calling this class, and the base type should never be a 

   170

 * array_type_declaration_c, but for now, let's leave it in...

   171

 */

   172

void *search_varfb_instance_type_c::visit(array_type_declaration_c *symbol) {

   173

  ERROR;

   174

  return NULL;

   175

}

   176

   177

/* array_specification [ASSIGN array_initialization] */

   178

/* array_initialization may be NULL ! */

   179

/* NOTE: I don't think this will ever get called, since in the visit method for array_variable_c

   180

 * we use the basetype_decl for recursively calling this class, and the base type should never be a 

   181

 * array_spec_init_c, but for now, let's leave it in...

   182

 */

   183

void *search_varfb_instance_type_c::visit(array_spec_init_c *symbol) {

   184

  /* Note that the 'array_specification' may be either an identifier of a previsously defined array type, 

   185

   * or an array_specification_c, so we can not stop here and simply return a array_spec_init_c, 

   186

   * especially if we are looking for the base class!

   187

   */

   188

  ERROR;

   189

  return NULL;

   190

}

   191

   192

/* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */

   193

/* NOTE: This method will be reached after being called from the 

   194

 * search_varfb_instance_type_c::visit(array_variable_c *symbol)

   195

 * method, so we must return the data type of the data stored in the array, 

   196

 * and not the data type of the array itself!

   197

 */

   198

void *search_varfb_instance_type_c::visit(array_specification_c *symbol) {

   199

  /* found the type of the element we were looking for! */

   200

  current_type_id       = symbol->non_generic_type_name;

   201

  current_basetype_decl = search_base_type.get_basetype_decl(current_type_id);

   202

  current_basetype_id   = search_base_type.get_basetype_id  (current_type_id);

   203

   204

  return NULL; 

   205

}

   206

   207

   208

/*  structure_type_name ':' structure_specification */

   209

/* NOTE: this is only used inside a TYPE ... END_TYPE declaration. 

   210

 * It is never used directly when declaring a new variable! 

   211

 */

   212

/* NOTE: I don't think this will ever get called, since in the visit method for structured_variable_c

   213

 * we use the basetype_decl for recursively calling this class, and the base type should never be a 

   214

 * structure_type_declaration_c, but for now, let's leave it in...

   215

 */

   216

void *search_varfb_instance_type_c::visit(structure_type_declaration_c *symbol) {

   217

  if (NULL == current_field_selector) ERROR;

   218

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

   219

  return NULL;

   220

  /* NOTE: structure_specification will point to either a

   221

   *       initialized_structure_c

   222

   *       OR A

   223

   *       structure_element_declaration_list_c

   224

   */

   225

}

   226

   227

/* structure_type_name ASSIGN structure_initialization */

   228

/* structure_initialization may be NULL ! */

   229

// SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)

   230

/* NOTE: only the initialized structure is never used when declaring a new variable instance */

   231

/* NOTE: I don't think this will ever get called, since in the visit method for structured_variable_c

   232

 * we use the basetype_decl for recursively calling this class, and the base type should never be a 

   233

 * initialized_structure_c, but for now, let's leave it in...

   234

 */

   235

void *search_varfb_instance_type_c::visit(initialized_structure_c *symbol)	{

   236

  if (NULL != current_field_selector) ERROR;

   237

   238

  /* recursively find out the data type of current_field_selector... */

   239

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

   240

  return NULL;

   241

}

   242

   243

/* helper symbol for structure_declaration */

   244

/* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */

   245

/* structure_element_declaration_list structure_element_declaration ';' */

   246

void *search_varfb_instance_type_c::visit(structure_element_declaration_list_c *symbol)	{

   247

  if (NULL == current_field_selector) ERROR;

   248

   249

  /* now search the structure declaration */

   250

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

   251

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

   252

  }

   253

   254

  return NULL;

   255

}

   256

   257

/*  structure_element_name ':' spec_init */

   258

void *search_varfb_instance_type_c::visit(structure_element_declaration_c *symbol) {

   259

  if (NULL == current_field_selector) ERROR;

   260

   261

  if (compare_identifiers(symbol->structure_element_name, current_field_selector) == 0) {

   262

    /* found the type of the element we were looking for! */

   263

    current_type_id       = symbol->spec_init;

   264

    current_basetype_decl = search_base_type.get_basetype_decl(current_type_id);

   265

    current_basetype_id   = search_base_type.get_basetype_id  (current_type_id);

   266

  }  

   267

   268

  /* Did not find the type of the element we were looking for! */

   269

  /* Will keep looking... */

   270

  return NULL;

   271

}

   272

   273

/* helper symbol for structure_initialization */

   274

/* structure_initialization: '(' structure_element_initialization_list ')' */

   275

/* structure_element_initialization_list ',' structure_element_initialization */

   276

void *search_varfb_instance_type_c::visit(structure_element_initialization_list_c *symbol) {ERROR; return NULL;} /* should never get called... */

   277

/*  structure_element_name ASSIGN value */

   278

void *search_varfb_instance_type_c::visit(structure_element_initialization_c *symbol) {ERROR; return NULL;} /* should never get called... */

   279

   280

   281

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

   282

/* B 1.4 - Variables */

   283

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

   284

// SYM_REF1(symbolic_variable_c, var_name)

   285

void *search_varfb_instance_type_c::visit(symbolic_variable_c *symbol) {

   286

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

   287

  return NULL;

   288

}

   289

   290

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

   291

/* B.1.4.1   Directly Represented Variables */

   292

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

   293

// SYM_TOKEN(direct_variable_c)

   294

/* We do not yet handle this. Will we ever need to handle it, as the data type of the direct variable is

   295

 * directly obtainable from the syntax of the direct variable itself?

   296

 */

   297

   298

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

   299

/* B 1.4.2 - Multi-element variables */

   300

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

   301

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

   302

// SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   303

/* NOTE: when passed a array_variable_c, which represents some IEC61131-3 code similar to X[42]

   304

 * we must return the data type of the value _stored_ in the array.

   305

 * If you want to get the data type of the array itself (i.e. just the X variable, without the [42])

   306

 * then this class must be called with the identifier_c 'X'.

   307

 */

   308

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

   309

  this->is_complex = true;

   310

   311

  /* determine the data type of the subscripted_variable... 

   312

   * This should be an array_specification_c

   313

   *    ARRAY [xx..yy] OF Stored_Data_Type

   314

   */

   315

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

   316

   317

  /* Now we determine the 'Stored_Data_Type', i.e. the data type of the variable stored in the array. */

   318

  if (NULL != current_basetype_decl) {

   319

    current_basetype_decl->accept(*this);

   320

  }

   321

   322

  return NULL;

   323

}

   324

   325

   326

/*  record_variable '.' field_selector */

   327

/*  WARNING: input and/or output variables of function blocks

   328

 *           may be accessed as fields of a structured variable!

   329

 *           Code handling a structured_variable_c must take

   330

 *           this into account!

   331

 */

   332

// SYM_REF2(structured_variable_c, record_variable, field_selector)

   333

void *search_varfb_instance_type_c::visit(structured_variable_c *symbol) {

   334

  this->is_complex = true;

   335

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

   336

   337

  /* Now we search for the data type of the field... But only if we were able to determine the data type of the variable */

   338

  if (NULL != current_basetype_decl) {

   339

    current_field_selector = symbol->field_selector;

   340

    current_basetype_decl->accept(*this);

   341

    current_field_selector = NULL;

   342

  }

   343

   344

  return NULL;

   345

}

   346

   347

   348

   349

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

   350

/* B.1.5 - Program organization units */

   351

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

   352

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

   353

/* B 1.5.2 - Function Blocks */

   354

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

   355

   356

/*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

   357

// SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)

   358

void *search_varfb_instance_type_c::visit(function_block_declaration_c *symbol) {

   359

  if (NULL == current_field_selector) ERROR;

   360

   361

  /* now search the function block declaration for the variable... */

   362

  /* If not found, these pointers will all be set to NULL!! */

   363

  search_var_instance_decl_c search_decl(symbol);

   364

  current_type_id       = search_decl.get_decl(current_field_selector);

   365

  current_basetype_decl = search_base_type.get_basetype_decl(current_type_id);

   366

  current_basetype_id   = search_base_type.get_basetype_id  (current_type_id);

   367

   368

  return NULL;

   369

}