1

/*

     2

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

     3

 *

     4

 *  Copyright (C) 2003-2011  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

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

    21

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

    22

 *

    23

 * Based on the

    24

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

    25

 *

    26

 */

    27

    28

    29

/*

    30

 * Conversion of st statements (i.e. ST code).

    31

 *

    32

 * This is part of the 4th stage that generates

    33

 * a C source program equivalent to the IL and ST, or SFC

    34

 * code.

    35

 */

    36

    37

    38

    39

#include "../../util/strdup.hh"

    40

    41

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

    42

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

    43

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

    44

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

    45

    46

    47

class generate_c_st_c: public generate_c_base_and_typeid_c {

    48

    49

  public:

    50

    typedef enum {

    51

      expression_vg,

    52

      complextype_base_vg,

    53

      complextype_suffix_vg,

    54

      fparam_output_vg

    55

    } variablegeneration_t;

    56

    57

  private:

    58

    /* When calling a function block, we must first find it's type,

    59

     * by searching through the declarations of the variables currently

    60

     * in scope.

    61

     * This class does just that...

    62

     * A new class is instantiated whenever we begin generating the code

    63

     * for a function block type declaration, or a program declaration.

    64

     * This object instance will then later be called while the

    65

     * function block's or the program's body is being handled.

    66

     *

    67

     * Note that functions cannot contain calls to function blocks,

    68

     * so we do not create an object instance when handling

    69

     * a function declaration.

    70

     */

    71

    search_fb_instance_decl_c    *search_fb_instance_decl;

    72

    search_varfb_instance_type_c *search_varfb_instance_type;

    73

    search_var_instance_decl_c   *search_var_instance_decl;

    74

    75

    symbol_c *scope_;

    76

    77

    symbol_c* current_array_type;

    78

    symbol_c* current_param_type;

    79

    80

    int fcall_number;

    81

    symbol_c *fbname;

    82

    83

    bool first_subrange_case_list;

    84

    85

    variablegeneration_t wanted_variablegeneration;

    86

    87

  public:

    88

    generate_c_st_c(stage4out_c *s4o_ptr, symbol_c *name, symbol_c *scope, const char *variable_prefix = NULL)

    89

    : generate_c_base_and_typeid_c(s4o_ptr) {

    90

      search_fb_instance_decl    = new search_fb_instance_decl_c   (scope);

    91

      search_varfb_instance_type = new search_varfb_instance_type_c(scope);

    92

      search_var_instance_decl   = new search_var_instance_decl_c  (scope);

    93

      scope_ = scope;

    94

    95

      this->set_variable_prefix(variable_prefix);

    96

      current_array_type = NULL;

    97

      current_param_type = NULL;

    98

      fcall_number = 0;

    99

      fbname = name;

   100

      wanted_variablegeneration = expression_vg;

   101

    }

   102

   103

    virtual ~generate_c_st_c(void) {

   104

      delete search_fb_instance_decl;

   105

      delete search_varfb_instance_type;

   106

      delete search_var_instance_decl;

   107

    }

   108

   109

   110

  public:

   111

    void generate(statement_list_c *stl) {

   112

      stl->accept(*this);

   113

    }

   114

   115

  private:

   116

   117

   118

   119

   120

   121

   122

void *print_getter(symbol_c *symbol) {

   123

  unsigned int vartype = analyse_variable_c::first_nonfb_vardecltype(symbol, scope_);

   124

  if (wanted_variablegeneration == fparam_output_vg) {

   125

    if (vartype == search_var_instance_decl_c::external_vt) {

   126

      if (!get_datatype_info_c::is_type_valid    (symbol->datatype)) ERROR;

   127

      if ( get_datatype_info_c::is_function_block(symbol->datatype))

   128

        s4o.print(GET_EXTERNAL_FB_BY_REF);

   129

      else

   130

        s4o.print(GET_EXTERNAL_BY_REF);

   131

    }

   132

    else if (vartype == search_var_instance_decl_c::located_vt)

   133

      s4o.print(GET_LOCATED_BY_REF);

   134

    else

   135

      s4o.print(GET_VAR_BY_REF);

   136

  }

   137

  else {

   138

    if (vartype == search_var_instance_decl_c::external_vt) {

   139

      if (!get_datatype_info_c::is_type_valid    (symbol->datatype)) ERROR;

   140

      if ( get_datatype_info_c::is_function_block(symbol->datatype))

   141

        s4o.print(GET_EXTERNAL_FB);

   142

      else

   143

        s4o.print(GET_EXTERNAL);

   144

    }

   145

    else if (vartype == search_var_instance_decl_c::located_vt)

   146

      s4o.print(GET_LOCATED);

   147

    else

   148

      s4o.print(GET_VAR);

   149

  }

   150

   151

  variablegeneration_t old_wanted_variablegeneration = wanted_variablegeneration;

   152

  s4o.print("(");

   153

  print_variable_prefix();  

   154

  wanted_variablegeneration = complextype_base_vg;

   155

  symbol->accept(*this);

   156

  s4o.print(",");

   157

  wanted_variablegeneration = complextype_suffix_vg;

   158

  symbol->accept(*this);

   159

  s4o.print(")");

   160

  wanted_variablegeneration = old_wanted_variablegeneration;

   161

  return NULL;

   162

}

   163

   164

   165

   166

void *print_setter(symbol_c* symbol,

   167

        symbol_c* type,

   168

        symbol_c* value,

   169

        symbol_c* fb_symbol = NULL,

   170

        symbol_c* fb_value = NULL) {

   171

   172

  unsigned int vartype;

   173

  if (fb_symbol == NULL) {

   174

    vartype = analyse_variable_c::first_nonfb_vardecltype(symbol, scope_);

   175

    symbol_c *first_nonfb = analyse_variable_c::find_first_nonfb(symbol);

   176

    if (first_nonfb == NULL) ERROR;

   177

    if (vartype == search_var_instance_decl_c::external_vt) {

   178

      if (!get_datatype_info_c::is_type_valid    (first_nonfb->datatype)) ERROR;

   179

      if ( get_datatype_info_c::is_function_block(first_nonfb->datatype)) // handle situation where we are copying a complete fb -> fb1.fb2.fb3 := fb4 (and fb3 is external!)

   180

        s4o.print(SET_EXTERNAL_FB);

   181

      else

   182

        s4o.print(SET_EXTERNAL);

   183

    }

   184

    else if (vartype == search_var_instance_decl_c::located_vt)

   185

      s4o.print(SET_LOCATED);

   186

    else

   187

      s4o.print(SET_VAR);

   188

  }

   189

  else {

   190

    vartype = search_var_instance_decl->get_vartype(fb_symbol);

   191

    if (vartype == search_var_instance_decl_c::external_vt)

   192

      s4o.print(SET_EXTERNAL_FB);

   193

    else

   194

      s4o.print(SET_VAR);

   195

  }

   196

  s4o.print("(");

   197

   198

  if (fb_symbol != NULL) {

   199

    if (vartype == search_var_instance_decl_c::external_vt){

   200

        print_variable_prefix();

   201

        s4o.print(",");

   202

        fb_symbol->accept(*this);

   203

        s4o.print("->");

   204

        symbol->accept(*this);

   205

    }else{

   206

        print_variable_prefix();

   207

        // It is my (MJS) conviction that by this time the following will always be true...

   208

        //   wanted_variablegeneration == expression_vg;

   209

        fb_symbol->accept(*this);

   210

        s4o.print(".,");

   211

        symbol->accept(*this);

   212

    }

   213

    s4o.print(",");

   214

    s4o.print(",");    

   215

  } else {

   216

    print_variable_prefix();

   217

    s4o.print(",");    

   218

    wanted_variablegeneration = complextype_base_vg;

   219

    symbol->accept(*this);

   220

    s4o.print(",");

   221

    wanted_variablegeneration = complextype_suffix_vg;

   222

    symbol->accept(*this);

   223

    s4o.print(",");

   224

  }

   225

  wanted_variablegeneration = expression_vg;

   226

  print_check_function(type, value, fb_value);

   227

  s4o.print(")");

   228

  wanted_variablegeneration = expression_vg;

   229

  return NULL;

   230

}

   231

   232

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

   233

/* B 1.3.3 - Derived data types */

   234

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

   235

   236

/*  signed_integer DOTDOT signed_integer */

   237

void *visit(subrange_c *symbol) {

   238

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

   239

  return NULL;

   240

}

   241

   242

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

   243

void *visit(array_specification_c *symbol) {

   244

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

   245

  return NULL;

   246

}

   247

   248

/*  enumerated_type_name ':' enumerated_spec_init */

   249

void *visit(enumerated_type_declaration_c *symbol) {

   250

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

   251

  return NULL;

   252

}

   253

   254

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

   255

/* B 1.4 - Variables */

   256

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

   257

void *visit(symbolic_variable_c *symbol) {

   258

  switch (wanted_variablegeneration) {

   259

    case complextype_base_vg:

   260

      symbol->var_name->accept(*this); //generate_c_base_c::visit(symbol);

   261

      break;

   262

    case complextype_suffix_vg:

   263

      break;

   264

    default:

   265

      if (this->is_variable_prefix_null()) {

   266

        if (wanted_variablegeneration == fparam_output_vg) {

   267

          s4o.print("&(");

   268

          generate_c_base_c::visit(symbol);

   269

          s4o.print(")");

   270

        }

   271

        else {

   272

          generate_c_base_c::visit(symbol);

   273

        }

   274

      }

   275

      else

   276

        print_getter(symbol);

   277

      break;

   278

  }

   279

  return NULL;

   280

}

   281

   282

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

   283

/* B.1.4.1   Directly Represented Variables */

   284

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

   285

// direct_variable: direct_variable_token   {$$ = new direct_variable_c($1);};

   286

void *visit(direct_variable_c *symbol) {

   287

  TRACE("direct_variable_c");

   288

  /* Do not use print_token() as it will change everything into uppercase */

   289

  if (strlen(symbol->value) == 0) ERROR;

   290

  if (this->is_variable_prefix_null()) {

   291

    if (wanted_variablegeneration != fparam_output_vg)

   292

      s4o.print("*(");

   293

  }

   294

  else {

   295

    switch (wanted_variablegeneration) {

   296

      case expression_vg:

   297

        s4o.print(GET_LOCATED);

   298

        s4o.print("(");

   299

        break;

   300

      case fparam_output_vg:

   301

        s4o.print(GET_LOCATED_BY_REF);

   302

        s4o.print("(");

   303

        break;

   304

      default:

   305

        break;

   306

    }

   307

  }

   308

  this->print_variable_prefix();

   309

  s4o.printlocation(symbol->value + 1);

   310

  if (( this->is_variable_prefix_null() && (wanted_variablegeneration != fparam_output_vg)) ||

   311

      (!this->is_variable_prefix_null() && (wanted_variablegeneration == expression_vg   )) ||

   312

      (!this->is_variable_prefix_null() && (wanted_variablegeneration == fparam_output_vg)))

   313

    s4o.print(")");

   314

  return NULL;

   315

}

   316

   317

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

   318

/* B.1.4.2   Multi-element Variables */

   319

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

   320

   321

// SYM_REF2(structured_variable_c, record_variable, field_selector)

   322

void *visit(structured_variable_c *symbol) {

   323

  TRACE("structured_variable_c");

   324

  switch (wanted_variablegeneration) {

   325

    case complextype_base_vg:

   326

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

   327

      /* NOTE: The following test includes a special case for SFC Steps. They are currently mapped onto a C data structure

   328

       *        that does not follow the standard IEC_<typename> pattern used for user defined structure datatypes 

   329

       *        (i.e. it does not include the 'values' and 'flag' structure 

   330

       *        elements that are tested by __GET_VAR and __SET_VAR acessor macros defined in acessor.h). However, the

   331

       *        STEP.T and STEP.X elements of this step structure are of the IEC_BOOL and IEC_TIME datatypes, and are 

   332

       *        actually structures that do have the 'value' and 'flags' elements. So, it is safe to say that any  variable

   333

       *        that is a STEPname is not of a complex type, as its .T and .X elements are and can later be safely accessed

   334

       *        using the __SET_VAR and __GET_VAR macros.

   335

       * 

   336

       *        For the above reason, a STEP must be handled as a FB, i.e. it does NOT contain the 'flags' and 'value' elements!

   337

       */

   338

      if (   get_datatype_info_c::is_function_block(symbol->record_variable->datatype)

   339

          || get_datatype_info_c::is_sfc_step      (symbol->record_variable->datatype)) {

   340

        if (NULL == symbol->record_variable->scope) ERROR;

   341

        search_var_instance_decl_c search_var_instance_decl(symbol->record_variable->scope);

   342

        if      (search_var_instance_decl_c::external_vt == search_var_instance_decl.get_vartype(get_var_name_c::get_last_field(symbol->record_variable)))

   343

          s4o.print("->");

   344

        else if (dynamic_cast<deref_operator_c *>(symbol->record_variable) != NULL)

   345

          s4o.print("->"); /* please read the comment in visit(deref_operator_c *) tio understand what this line is doing! */

   346

        else  

   347

          s4o.print(".");

   348

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

   349

      }

   350

      break;

   351

    case complextype_suffix_vg:

   352

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

   353

      // the following condition MUST be a negation of the above condition used in the 'case complextype_base_vg:'

   354

      if (!(   get_datatype_info_c::is_function_block(symbol->record_variable->datatype)     // if the record variable is not a FB... 

   355

            || get_datatype_info_c::is_sfc_step      (symbol->record_variable->datatype))) { // ...nor an SFC step name, then it will certainly be a structure!

   356

        if (dynamic_cast<deref_operator_c *>(symbol->record_variable) != NULL)

   357

          s4o.print("->"); /* please read the comment in visit(deref_operator_c *) tio understand what this line is doing! */

   358

        else

   359

          s4o.print(".");

   360

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

   361

      }

   362

      break;

   363

    default:

   364

      if (this->is_variable_prefix_null()) {

   365

        /* We are writing code for a FUNCTION. In this case, deref_operator_c are not transformed into the C pointer derefence syntax '->' (e.g. ptr->elem).

   366

         * We use instead the '*' syntax (e.g. (*ptr).elem)

   367

         * While in FB the '->' is generated by this structured_variable_c visitor, in Functions the '*' syntax is generated by the deref_operator_c visitor

   368

         * This is why here we do NOT have --> {if (dynamic_cast<deref_operator_c *>(symbol->record_variable) != NULL)  ..}

   369

	 *  

   370

	 * please read the comment in visit(deref_operator_c *) for more information!

   371

         */

   372

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

   373

        s4o.print(".");

   374

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

   375

      }

   376

      else

   377

        print_getter(symbol);

   378

      break;

   379

  }

   380

  return NULL;

   381

}

   382

   383

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

   384

//SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   385

void *visit(array_variable_c *symbol) {

   386

  switch (wanted_variablegeneration) {

   387

    case complextype_base_vg:

   388

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

   389

      break;

   390

    case complextype_suffix_vg:

   391

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

   392

   393

      current_array_type = search_varfb_instance_type->get_basetype_decl(symbol->subscripted_variable);

   394

      if (current_array_type == NULL) ERROR;

   395

   396

      if (dynamic_cast<deref_operator_c *>(symbol->subscripted_variable) != NULL)

   397

        s4o.print("->"); /* please read the comment in visit(deref_operator_c *) tio understand what this line is doing! */

   398

      else

   399

        s4o.print(".");

   400

      s4o.print("table");

   401

      wanted_variablegeneration = expression_vg;

   402

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

   403

      wanted_variablegeneration = complextype_suffix_vg;

   404

   405

      current_array_type = NULL;

   406

      break;

   407

    default:

   408

      if (this->is_variable_prefix_null()) {

   409

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

   410

   411

        current_array_type = search_varfb_instance_type->get_basetype_decl(symbol->subscripted_variable);

   412

        if (current_array_type == NULL) ERROR;

   413

   414

        s4o.print(".table");

   415

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

   416

   417

        current_array_type = NULL;

   418

      }

   419

      else

   420

        print_getter(symbol);

   421

      break;

   422

  }

   423

  return NULL;

   424

}

   425

   426

/* subscript_list ',' subscript */

   427

void *visit(subscript_list_c *symbol) {

   428

  array_dimension_iterator_c* array_dimension_iterator = new array_dimension_iterator_c(current_array_type);

   429

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

   430

    symbol_c* dimension = array_dimension_iterator->next();

   431

    if (dimension == NULL) ERROR;

   432

   433

    s4o.print("[(");

   434

    symbol->get_element(i)->accept(*this);

   435

    s4o.print(") - (");

   436

    dimension->accept(*this);

   437

    s4o.print(")]");

   438

  }

   439

  delete array_dimension_iterator;

   440

  return NULL;

   441

}

   442

   443

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

   444

/* B 1.4.3 - Declaration & Initialisation */

   445

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

   446

   447

/* helper symbol for structure_initialization */

   448

/* structure_element_initialization_list ',' structure_element_initialization */

   449

void *visit(structure_element_initialization_list_c *symbol) {

   450

  generate_c_structure_initialization_c *structure_initialization = new generate_c_structure_initialization_c(&s4o);

   451

  structure_initialization->init_structure_default(this->current_param_type);

   452

  structure_initialization->init_structure_values(symbol);

   453

  delete structure_initialization;

   454

  return NULL;

   455

}

   456

   457

/* helper symbol for array_initialization */

   458

/* array_initial_elements_list ',' array_initial_elements */

   459

void *visit(array_initial_elements_list_c *symbol) {

   460

  generate_c_array_initialization_c *array_initialization = new generate_c_array_initialization_c(&s4o);

   461

  array_initialization->init_array_size(this->current_param_type);

   462

  array_initialization->init_array_values(symbol);

   463

  delete array_initialization;

   464

  return NULL;

   465

}

   466

   467

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

   468

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

   469

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

   470

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

   471

/* B 3.1 - Expressions */

   472

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

   473

void *visit(deref_operator_c *symbol) {

   474

  /* When producing C code for FUNCTION_BLOCKS, we use the '*' syntax (e.g. (*ptr).elem)

   475

   * When producing C code for a FUNCTION_BLOCK, the deref_operator_c are transformed in two ways, depending on where they occur.

   476

   *    - deref_operator between a struct and its elem (e.g. struct_ref^.elem1) 

   477

   *        are transformed into C using the C pointer derefence syntax '->' (e.g. struct_ref->elem1).

   478

   *        (In this case, '->' is generated by this structured_variable_c visitor)

   479

   *    - deref_operator at the end of a struct variable (e.g. struct.elem_ptr^)

   480

   *        are transformed using the '*' syntax for C pointer dereferencing (e.g. *(struct.elem_ptr) )

   481

   * 

   482

   *   NOTE: Ideally, we should always use the '*' C pointer dereferencing syntax. However, due to the

   483

   *         was the GET_VAR and SET_VAR are transformed into C, this does not work for '^' between a struct and its 

   484

   *         element (e.g. struct_ref^.elem), which is whey in this case only we use the '->' syntax.

   485

   *   NOTE: The use of the -> syntax means that pointers to pointers are not supported betweem a struct and its elem

   486

   *         (e.g. . struct_ref_ref^^.elem) as this would be transformed into the invalid C code struct_ref_ref->->elem.

   487

   *         This is why we add a test for this case, and bug out with an error if we encounter it!!

   488

   */

   489

  if (this->is_variable_prefix_null()) {  

   490

    /* For code in FUNCTIONs */

   491

    s4o.print("(*");