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/*

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

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 *

     4

 *  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)

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

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 *

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

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

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

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 *  (at your option) any later version.

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 *

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

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

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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *  GNU General Public License for more details.

    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

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

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 *

    26

 */

    27

    28

    29

/*

    30

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

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 *

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 * This is part of the 4th stage that generates

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

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 * code.

    35

 */

    36

    37

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    39

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

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    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,

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      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.

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     * This object instance will then later be called while the

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

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     *

    67

     * Note that functions cannot contain calls to function blocks,

    68

     * so we do not create an object instance when handling

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     * 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) {

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      search_fb_instance_decl    = new search_fb_instance_decl_c   (scope);

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      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) {

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  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) {

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

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

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        s4o.print(GET_EXTERNAL_FB_BY_REF);

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      else

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        s4o.print(GET_EXTERNAL_BY_REF);

   131

    }

   132

    else if (vartype == search_var_instance_decl_c::located_vt)

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      s4o.print(GET_LOCATED_BY_REF);

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    else

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      s4o.print(GET_VAR_BY_REF);

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  }

   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))

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        s4o.print(GET_EXTERNAL_FB);

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      else

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        s4o.print(GET_EXTERNAL);

   144

    }

   145

    else if (vartype == search_var_instance_decl_c::located_vt)

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      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,

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        symbol_c* type,

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        symbol_c* value,

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        symbol_c* fb_symbol = NULL,

   170

        symbol_c* fb_value = NULL) {

   171

   172

  if (fb_symbol == NULL) {

   173

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

   174

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

   175

    if (first_nonfb == NULL) ERROR;

   176

    if (vartype == search_var_instance_decl_c::external_vt) {

   177

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

   178

      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!)

   179

        s4o.print(SET_EXTERNAL_FB);

   180

      else

   181

        s4o.print(SET_EXTERNAL);

   182

    }

   183

    else if (vartype == search_var_instance_decl_c::located_vt)

   184

      s4o.print(SET_LOCATED);

   185

    else

   186

      s4o.print(SET_VAR);

   187

  }

   188

  else {

   189

    unsigned int vartype = search_var_instance_decl->get_vartype(fb_symbol);

   190

    if (vartype == search_var_instance_decl_c::external_vt)

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      s4o.print(SET_EXTERNAL_FB);

   192

    else

   193

      s4o.print(SET_VAR);

   194

  }

   195

  s4o.print("(");

   196

   197

  if (fb_symbol != NULL) {

   198

    print_variable_prefix();

   199

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

   200

    //   wanted_variablegeneration == expression_vg;

   201

    fb_symbol->accept(*this);

   202

    s4o.print(".,");

   203

    symbol->accept(*this);

   204

    s4o.print(",");

   205

    s4o.print(",");    

   206

  } else {

   207

    print_variable_prefix();

   208

    s4o.print(",");    

   209

    wanted_variablegeneration = complextype_base_vg;

   210

    symbol->accept(*this);

   211

    s4o.print(",");

   212

    wanted_variablegeneration = complextype_suffix_vg;

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    symbol->accept(*this);

   214

    s4o.print(",");

   215

  }

   216

  wanted_variablegeneration = expression_vg;

   217

  print_check_function(type, value, fb_value);

   218

  s4o.print(")");

   219

  wanted_variablegeneration = expression_vg;

   220

  return NULL;

   221

}

   222

   223

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

   224

/* B 1.3.3 - Derived data types */

   225

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

   226

   227

/*  signed_integer DOTDOT signed_integer */

   228

void *visit(subrange_c *symbol) {

   229

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

   230

  return NULL;

   231

}

   232

   233

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

   234

void *visit(array_specification_c *symbol) {

   235

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

   236

  return NULL;

   237

}

   238

   239

/*  enumerated_type_name ':' enumerated_spec_init */

   240

void *visit(enumerated_type_declaration_c *symbol) {

   241

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

   242

  return NULL;

   243

}

   244

   245

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

   246

/* B 1.4 - Variables */

   247

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

   248

void *visit(symbolic_variable_c *symbol) {

   249

  switch (wanted_variablegeneration) {

   250

    case complextype_base_vg:

   251

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

   252

      break;

   253

    case complextype_suffix_vg:

   254

      break;

   255

    default:

   256

      if (this->is_variable_prefix_null()) {

   257

        if (wanted_variablegeneration == fparam_output_vg) {

   258

          s4o.print("&(");

   259

          generate_c_base_c::visit(symbol);

   260

          s4o.print(")");

   261

        }

   262

        else {

   263

          generate_c_base_c::visit(symbol);

   264

        }

   265

      }

   266

      else

   267

        print_getter(symbol);

   268

      break;

   269

  }

   270

  return NULL;

   271

}

   272

   273

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

   274

/* B.1.4.1   Directly Represented Variables */

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

   276

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

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void *visit(direct_variable_c *symbol) {

   278

  TRACE("direct_variable_c");

   279

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

   280

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

   281

  if (this->is_variable_prefix_null()) {

   282

    if (wanted_variablegeneration != fparam_output_vg)

   283

      s4o.print("*(");

   284

  }

   285

  else {

   286

    switch (wanted_variablegeneration) {

   287

      case expression_vg:

   288

        s4o.print(GET_LOCATED);

   289

        s4o.print("(");

   290

        break;

   291

      case fparam_output_vg:

   292

        s4o.print(GET_LOCATED_BY_REF);

   293

        s4o.print("(");

   294

        break;

   295

      default:

   296

        break;

   297

    }

   298

  }

   299

  this->print_variable_prefix();

   300

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

   301

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

   302

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

   303

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

   304

    s4o.print(")");

   305

  return NULL;

   306

}

   307

   308

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

   309

/* B.1.4.2   Multi-element Variables */

   310

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

   311

   312

// SYM_REF2(structured_variable_c, record_variable, field_selector)

   313

void *visit(structured_variable_c *symbol) {

   314

  TRACE("structured_variable_c");

   315

  switch (wanted_variablegeneration) {

   316

    case complextype_base_vg:

   317

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

   318

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

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

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

   321

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

   322

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

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

   324

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

   325

       *        using the __SET_VAR and __GET_VAR macros.

   326

       * 

   327

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

   328

       */

   329

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

   330

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

   331

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

   332

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

   333

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

   334

          s4o.print("->");

   335

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

   336

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

   337

        else  

   338

          s4o.print(".");

   339

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

   340

      }

   341

      break;

   342

    case complextype_suffix_vg:

   343

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

   344

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

   345

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

   346

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

   347

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

   348

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

   349

        else

   350

          s4o.print(".");

   351

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

   352

      }

   353

      break;

   354

    default:

   355

      if (this->is_variable_prefix_null()) {

   356

        /* 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).

   357

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

   358

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

   359

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

   360

	 *  

   361

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

   362

         */

   363

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

   364

        s4o.print(".");

   365

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

   366

      }

   367

      else

   368

        print_getter(symbol);

   369

      break;

   370

  }

   371

  return NULL;

   372

}

   373

   374

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

   375

//SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   376

void *visit(array_variable_c *symbol) {

   377

  switch (wanted_variablegeneration) {

   378

    case complextype_base_vg:

   379

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

   380

      break;

   381

    case complextype_suffix_vg:

   382

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

   383

   384

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

   385

      if (current_array_type == NULL) ERROR;

   386

   387

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

   388

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

   389

      else

   390

        s4o.print(".");

   391

      s4o.print("table");

   392

      wanted_variablegeneration = expression_vg;

   393

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

   394

      wanted_variablegeneration = complextype_suffix_vg;

   395

   396

      current_array_type = NULL;

   397

      break;

   398

    default:

   399

      if (this->is_variable_prefix_null()) {

   400

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

   401

   402

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

   403

        if (current_array_type == NULL) ERROR;

   404

   405

        s4o.print(".table");

   406

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

   407

   408

        current_array_type = NULL;

   409

      }

   410

      else

   411

        print_getter(symbol);

   412

      break;

   413

  }

   414

  return NULL;

   415

}

   416

   417

/* subscript_list ',' subscript */

   418

void *visit(subscript_list_c *symbol) {

   419

  array_dimension_iterator_c* array_dimension_iterator = new array_dimension_iterator_c(current_array_type);

   420

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

   421

    symbol_c* dimension = array_dimension_iterator->next();

   422

    if (dimension == NULL) ERROR;

   423

   424

    s4o.print("[(");

   425

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

   426

    s4o.print(") - (");

   427

    dimension->accept(*this);

   428

    s4o.print(")]");

   429

  }

   430

  delete array_dimension_iterator;

   431

  return NULL;

   432

}

   433

   434

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

   435

/* B 1.4.3 - Declaration & Initialisation */

   436

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

   437

   438

/* helper symbol for structure_initialization */

   439

/* structure_element_initialization_list ',' structure_element_initialization */

   440

void *visit(structure_element_initialization_list_c *symbol) {

   441

  generate_c_structure_initialization_c *structure_initialization = new generate_c_structure_initialization_c(&s4o);

   442

  structure_initialization->init_structure_default(this->current_param_type);

   443

  structure_initialization->init_structure_values(symbol);

   444

  delete structure_initialization;

   445

  return NULL;

   446

}

   447

   448

/* helper symbol for array_initialization */

   449

/* array_initial_elements_list ',' array_initial_elements */

   450

void *visit(array_initial_elements_list_c *symbol) {

   451

  generate_c_array_initialization_c *array_initialization = new generate_c_array_initialization_c(&s4o);

   452

  array_initialization->init_array_size(this->current_param_type);

   453

  array_initialization->init_array_values(symbol);

   454

  delete array_initialization;

   455

  return NULL;

   456

}

   457

   458

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

   459

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

   460

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

   461

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

   462

/* B 3.1 - Expressions */

   463

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

   464

void *visit(deref_operator_c *symbol) {

   465

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

   466

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

   467

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

   468

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

   469

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

   470

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

   471

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

   472

   * 

   473

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

   474

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

   475

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

   476

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

   477

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

   478

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

   479

   */

   480

  if (this->is_variable_prefix_null()) {  

   481

    /* For code in FUNCTIONs */

   482

    s4o.print("(*");  

   483

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

   484

    s4o.print(")");  

   485

  } else {

   486

    /* For code in FBs, and PROGRAMS... */

   487

    if (   (NULL == dynamic_cast<structured_variable_c *>(symbol->parent)) 

   488

        && (NULL == dynamic_cast<     array_variable_c *>(symbol->parent))) {

   489

      s4o.print("(*");  

   490

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

   491

      s4o.print(")");