1

/*

     2

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

     3

 *

     4

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

     5

 *

     6

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

     7

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

     8

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

     9

 *  (at your option) any later version.

    10

 *

    11

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

    12

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

    13

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    14

 *  GNU General Public License for more details.

    15

 *

    16

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

    17

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

    18

 *

    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

    24

/*

    25

 * An IEC 61131-3 compiler.

    26

 *

    27

 * Based on the

    28

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

    29

 *

    30

 */

    31

    32

    33

/*

    34

 *  Do flow control analysis of the IEC 61131-3 code.

    35

 *

    36

 *  We currently only do this for IL code.

    37

 *  This class will annotate the abstract syntax tree, by filling in the

    38

 *  prev_il_instruction variable in the il_instruction_c, so it points to

    39

 *  the previous il_instruction_c object in the instruction list instruction_list_c.

    40

 *

    41

 *  Since IL code can contain jumps (JMP), the same il_instruction may effectively have

    42

 *  several previous il_instructions. In order to accommodate this, each il_instruction

    43

 *  will maintain a vector (i..e an array) of pointers to all the previous il_instructions.

    44

 *  We do however attempt to guarantee that the first element in the vector (array) will preferentially

    45

 *  point to the il instruction that is right before / imediately preceding the current il instructions, 

    46

 *  i.e. the first element in the array will tend to point to the previous il_instruction

    47

 *  that is not a jump JMP IL instruction!

    48

 *

    49

 *  The result will essentially be a graph of il_instruction_c objects, each 

    50

 *  pointing to the previous il_instruction_c object.

    51

 *

    52

 *  The reality is we will get several independent and isolated linked lists

    53

 *  (actually, since we now process labels correctly, this is really a graph):

    54

 *  one for each block of IL code (e.g. inside a Function, FB or Program).

    55

 *  Additionally, when the IL code has an expression (expression_c object), we will actually

    56

 *  have one more isolated linked list for the IL code inside that expression.

    57

 *

    58

 *  e.g.

    59

 *       line_1:   LD 1

    60

 *       line_2:   ADD (42

    61

 *       line_3:        ADD B

    62

 *       line_4:        ADD C 

    63

 *       line_5:       )

    64

 *       line_6:   ADD D

    65

 *       line_7:   ST  E

    66

 * 

    67

 *     will result in two independent linked lists:

    68

 *       main list:  line_7 -> line_6 -> line2 -> line_1

    69

 *       expr list:  lin4_4 -> line_3 -> (operand of line_2, i.e. '42')

    70

 * 

    71

 * 

    72

 *     In the main list, each:

    73

 *        line_x: IL_operation IL_operand

    74

 *      is encoded as

    75

 *          il_instruction_c(label, il_incomplete_instruction)

    76

 *      these il_instruction_c objects will point back to the previous il_instruction_c object.

    77

 *

    78

 *     In the expr list, each 

    79

 *        line_x:        IL_operation IL_operand

    80

 *      is encoded as

    81

 *          il_simple_instruction_c(il_simple_instruction)

    82

 *      these il_simple_instruction_c objects will point back to the previous il_simple_instruction_c object,

    83

 *      except the for the first il_simple_instruction_c object in the list, which will point back to

    84

 *      the first il_operand (in the above example, '42'), or NULL is it does not exist.

    85

 *          

    86

 *

    87

 * label:

    88

 *   identifier_c  

    89

 *   

    90

 * il_incomplete_instruction:

    91

 *   il_simple_operation   (il_simple_operation_c, il_function_call_c)

    92

 * | il_expression         (il_expression_c)

    93

 * | il_jump_operation     (il_jump_operation_c)

    94

 * | il_fb_call            (il_fb_call_c)

    95

 * | il_formal_funct_call  (il_formal_funct_call_c)

    96

 * | il_return_operator    (RET_operator_c, RETC_operator_c, RETCN_operator_c)

    97

 *  

    98

 * 

    99

 * il_expression_c(il_expr_operator, il_operand, simple_instr_list)

   100

 * 

   101

 * il_operand:

   102

 *   variable            (symbolic_variable_c, direct_variable_c, array_variable_c, structured_variable_c)  

   103

 * | enumerated_value    (enumerated_value_c)

   104

 * | constant            (lots of literal classes _c)

   105

 * 

   106

 * simple_instr_list:

   107

 *   list of il_simple_instruction

   108

 * 

   109

 * il_simple_instruction:

   110

 *   il_simple_operation       (il_simple_operation_c, il_function_call_c)

   111

 * | il_expression             (il_expression_c)

   112

 * | il_formal_funct_call      (il_formal_funct_call_c)

   113

 * 

   114

 */

   115

   116

#include "flow_control_analysis.hh"

   117

   118

   119

   120

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

   121

static int debug = 0;

   122

   123

flow_control_analysis_c::flow_control_analysis_c(symbol_c *ignore) {

   124

  prev_il_instruction = NULL;

   125

  curr_il_instruction = NULL;

   128

}

   129

   130

flow_control_analysis_c::~flow_control_analysis_c(void) {

   131

}

   132

   133

   134

   135

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

   136

/* B 1.5 Program organization units */

   137

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

   138

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

   139

/* B 1.5.1 Functions */

   140

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

   141

void *flow_control_analysis_c::visit(function_declaration_c *symbol) {

   142

	search_il_label = new search_il_label_c(symbol);

   143

	if (debug) printf("Doing flow control analysis in body of function %s\n", ((token_c *)(symbol->derived_function_name))->value);

   144

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

   145

	delete search_il_label;

   146

	search_il_label = NULL;

   147

	return NULL;

   148

}

   149

   150

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

   151

/* B 1.5.2 Function blocks */

   152

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

   153

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

   154

	search_il_label = new search_il_label_c(symbol);

   155

	if (debug) printf("Doing flow control analysis in body of FB %s\n", ((token_c *)(symbol->fblock_name))->value);

   156

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

   157

	delete search_il_label;

   158

	search_il_label = NULL;

   159

	return NULL;

   160

}

   161

   162

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

   163

/* B 1.5.3 Programs */

   164

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

   165

void *flow_control_analysis_c::visit(program_declaration_c *symbol) {

   166

	search_il_label = new search_il_label_c(symbol);

   167

	if (debug) printf("Doing flow control analysis in body of program %s\n", ((token_c *)(symbol->program_type_name))->value);

   168

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

   169

	delete search_il_label;

   170

	search_il_label = NULL;

   171

	return NULL;

   172

}

   173

   174

   175

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

   176

/* B 1.7 Configuration elements */

   177

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

   178

void *flow_control_analysis_c::visit(configuration_declaration_c *symbol) {

   179

	return NULL;

   180

}

   181

   182

   183

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

   184

/* B.2 - Language IL (Instruction List) */

   185

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

   186

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

   187

/* B 2.1 Instructions and Operands */

   188

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

   189

   190

/*| instruction_list il_instruction */

   191

// SYM_LIST(instruction_list_c)

   192

void *flow_control_analysis_c::visit(instruction_list_c *symbol) {

   193

	prev_il_instruction_is_JMP_or_RET = false;

   194

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

   195

		prev_il_instruction = NULL;

   196

		if (i > 0) prev_il_instruction = symbol->elements[i-1];

   197

		curr_il_instruction = symbol->elements[i];

   198

		curr_il_instruction->accept(*this);

   199

		curr_il_instruction = NULL;

   200

	}

   201

	return NULL;

   202

}

   203

   204

/* | label ':' [il_incomplete_instruction] eol_list */

   205

// SYM_REF2(il_instruction_c, label, il_instruction)

   206

// void *visit(instruction_list_c *symbol);

   207

void *flow_control_analysis_c::visit(il_instruction_c *symbol) {

   208

	if ((NULL != prev_il_instruction) && (!prev_il_instruction_is_JMP_or_RET))

   209

		/* We try to guarantee that the previous il instruction that is in the previous line, will occupy the first element of the vector.

   210

		 * In order to do that, we use insert() instead of push_back()

   211

		 */

   212

		symbol->prev_il_instruction.insert(symbol->prev_il_instruction.begin() , prev_il_instruction);

   213

   214

	/* check if it is an il_expression_c, a JMP[C[N]], or a RET, and if so, handle it correctly */

   215

	prev_il_instruction_is_JMP_or_RET = false;

   216

	if (NULL != symbol->il_instruction)

   217

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

   218

	return NULL;

   219

}

   220

   221

   222

   223

/* | il_simple_operator [il_operand] */

   224

// SYM_REF2(il_simple_operation_c, il_simple_operator, il_operand)

   225

// void *flow_control_analysis_c::visit(il_simple_operation_c *symbol)

   226

   227

   228

   229

/* | function_name [il_operand_list] */

   230

/* NOTE: The parameters 'called_function_declaration' and 'extensible_param_count' are used to pass data between the stage 3 and stage 4. */

   231

// SYM_REF2(il_function_call_c, function_name, il_operand_list, symbol_c *called_function_declaration; int extensible_param_count;)

   232

// void *flow_control_analysis_c::visit(il_function_call_c *symbol) 

   233

   234

   235

/* | il_expr_operator '(' [il_operand] eol_list [simple_instr_list] ')' */

   236

// SYM_REF3(il_expression_c, il_expr_operator, il_operand, simple_instr_list);

   237

void *flow_control_analysis_c::visit(il_expression_c *symbol) {

   238

	if(NULL == symbol->simple_instr_list) 

   239

		/* nothing to do... */

   240

		return NULL;

   241

   242

	symbol_c *save_prev_il_instruction = prev_il_instruction;

   243

	prev_il_instruction = symbol->il_operand;

   244

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

   245

	prev_il_instruction = save_prev_il_instruction;

   246

	return NULL;

   247

}

   248

   249

   250

/*  il_jump_operator label */

   251

// SYM_REF2(il_jump_operation_c, il_jump_operator, label)

   252

void *flow_control_analysis_c::visit(il_jump_operation_c *symbol) {

   253

  /* search for the il_instruction_c containing the label */

   254

  il_instruction_c *destination = search_il_label->find_label(symbol->label);

   255

   256

  /* give the visit(JMP_operator *) an oportunity to set the prev_il_instruction_is_JMP_or_RET flag! */

   257

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

   258

  /* add, to that il_instruction's list of prev_il_intsructions, the curr_il_instruction */

   259

  if (NULL != destination)

   260

    destination->prev_il_instruction.push_back(curr_il_instruction);

   261

  return NULL;

   262

}

   263

   264

   265

/*   il_call_operator prev_declared_fb_name

   266

 * | il_call_operator prev_declared_fb_name '(' ')'

   267

 * | il_call_operator prev_declared_fb_name '(' eol_list ')'

   268

 * | il_call_operator prev_declared_fb_name '(' il_operand_list ')'

   269

 * | il_call_operator prev_declared_fb_name '(' eol_list il_param_list ')'

   270

 */

   271

/* NOTE: The parameter 'called_fb_declaration'is used to pass data between stage 3 and stage4 (although currently it is not used in stage 4 */

   272

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

   273

// void *flow_control_analysis_c::visit(il_fb_call_c *symbol)

   274

   275

   276

/* | function_name '(' eol_list [il_param_list] ')' */

   277

/* NOTE: The parameter 'called_function_declaration' is used to pass data between the stage 3 and stage 4. */

   278

// SYM_REF2(il_formal_funct_call_c, function_name, il_param_list, symbol_c *called_function_declaration; int extensible_param_count;)

   279

// void *flow_control_analysis_c::visit(il_formal_funct_call_c *symbol)

   280

   281

   282

   283

//  void *visit(il_operand_list_c *symbol);

   284

void *flow_control_analysis_c::visit(simple_instr_list_c *symbol) {

   285

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

   286

		/* The prev_il_instruction for element[0] was set in visit(il_expression_c *) */

   287

		if (i>0) prev_il_instruction = symbol->elements[i-1];

   288

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

   289

	}

   290

	return NULL;

   291

}

   292

   293

   294

// SYM_REF1(il_simple_instruction_c, il_simple_instruction, symbol_c *prev_il_instruction;)

   295

void *flow_control_analysis_c::visit(il_simple_instruction_c*symbol) {

   296

	if (NULL != prev_il_instruction)

   297

		/* We try to guarantee that the previous il instruction that is in the previous line, will occupy the first element of the vector.

   298

		 * In order to do that, we use insert() instead of push_back()

   299

		 */

   300

		symbol->prev_il_instruction.insert(symbol->prev_il_instruction.begin() , prev_il_instruction);

   301

	return NULL;

   302

}

   303

   304

   305

/*

   306

    void *visit(il_param_list_c *symbol);

   307

    void *visit(il_param_assignment_c *symbol);

   308

    void *visit(il_param_out_assignment_c *symbol);

   309

 */

   310

   311

   312

   313

   314

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

   315

/* B 2.2 Operators */

   316

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

   317

// void *visit(   LD_operator_c *symbol);

   318

// void *visit(  LDN_operator_c *symbol);

   319

// void *visit(   ST_operator_c *symbol);

   320

// void *visit(  STN_operator_c *symbol);

   321

// void *visit(  NOT_operator_c *symbol);

   322

// void *visit(    S_operator_c *symbol);

   323

// void *visit(    R_operator_c *symbol);

   324

// void *visit(   S1_operator_c *symbol);

   325

// void *visit(   R1_operator_c *symbol);

   326

// void *visit(  CLK_operator_c *symbol);

   327

// void *visit(   CU_operator_c *symbol);

   328

// void *visit(   CD_operator_c *symbol);

   329

// void *visit(   PV_operator_c *symbol);

   330

// void *visit(   IN_operator_c *symbol);

   331

// void *visit(   PT_operator_c *symbol);

   332

// void *visit(  AND_operator_c *symbol);

   333

// void *visit(   OR_operator_c *symbol);

   334

// void *visit(  XOR_operator_c *symbol);

   335

// void *visit( ANDN_operator_c *symbol);

   336

// void *visit(  ORN_operator_c *symbol);

   337

// void *visit( XORN_operator_c *symbol);

   338

// void *visit(  ADD_operator_c *symbol);

   339

// void *visit(  SUB_operator_c *symbol);

   340

// void *visit(  MUL_operator_c *symbol);

   341

// void *visit(  DIV_operator_c *symbol);

   342

// void *visit(  MOD_operator_c *symbol);

   343

// void *visit(   GT_operator_c *symbol);

   344

// void *visit(   GE_operator_c *symbol);

   345

// void *visit(   EQ_operator_c *symbol);

   346

// void *visit(   LT_operator_c *symbol);

   347

// void *visit(   LE_operator_c *symbol);

   348

// void *visit(   NE_operator_c *symbol);

   349

// void *visit(  CAL_operator_c *symbol);

   350

// void *visit( CALC_operator_c *symbol);

   351

// void *visit(CALCN_operator_c *symbol);

   352

   353

/* this next visit function will be called directly from visit(il_instruction_c *) */

   354

void *flow_control_analysis_c::visit(  RET_operator_c *symbol) {

   355

	prev_il_instruction_is_JMP_or_RET = true;

   356

	return NULL;

   357

}

   358

   359

// void *visit( RETC_operator_c *symbol);

   360

// void *visit(RETCN_operator_c *symbol);

   361

   362

/* this next visit function will be called from visit(il_jump_operation_c *) */

   363

void *flow_control_analysis_c::visit(  JMP_operator_c *symbol) {

   364

	prev_il_instruction_is_JMP_or_RET = true;

   365

	return NULL;

   366

}

   367

   368

// void *visit( JMPC_operator_c *symbol);

   369

// void *visit(JMPCN_operator_c *symbol);

   370

   371

/* Symbol class handled together with function call checks */

   372

// void *visit(il_assign_operator_c *symbol, variable_name);

   373

/* Symbol class handled together with function call checks */

   374

// void *visit(il_assign_operator_c *symbol, option, variable_name);

   375