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/*

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

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 *

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 *  Copyright (C) 2009-2012  Mario de Sousa (msousa@fe.up.pt)

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 *  Copyright (C) 2012       Manuele Conti (manuele.conti@sirius-es.it)

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 *  Copyright (C) 2012       Matteo Facchinetti (matteo.facchinetti@sirius-es.it)

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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.

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 *

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

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

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 *

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 *

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

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

    24

 */

    25

    26

/*

    27

 * An IEC 61131-3 compiler.

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 *

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 * Based on the

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

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 *

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 */

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    34

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/*

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 *  Narrow class select and store a data type from candidate data types list for all symbols

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 */

    38

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#include "narrow_candidate_datatypes.hh"

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#include "datatype_functions.hh"

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#include <typeinfo>

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#include <list>

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#include <string>

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#include <string.h>

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#include <strings.h>

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    47

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

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static int debug = 0;

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    51

narrow_candidate_datatypes_c::narrow_candidate_datatypes_c(symbol_c *ignore) {

    52

}

    53

    54

narrow_candidate_datatypes_c::~narrow_candidate_datatypes_c(void) {

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}

    56

    57

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

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

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

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

    63

	 * However, I (Mario) am not too sure of this, so if the compiler ever aborts here, please analyse the situation

    64

	 * carefully as it might be perfectly legal and something I have missed!

    65

	 */

    66

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

    67

    68

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

    69

    70

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

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

    72

	else {

    73

		if (NULL == symbol->datatype)   

    74

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

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			symbol->datatype = datatype; 

    76

		else {

    77

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

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

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

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// 			else 

    81

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

    82

		}

    83

	}

    84

}

    85

    86

    87

    88

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

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

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

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	if (NULL == symbol) ERROR;

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

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

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}

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    96

    97

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bool narrow_candidate_datatypes_c::is_widening_compatible(symbol_c *left_type, symbol_c *right_type, symbol_c *result_type, const struct widen_entry widen_table[]) {

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

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

   101

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

   102

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

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			return true;

   104

		}

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	}

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	return false;

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}

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   109

/*

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

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

   112

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

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 */

   114

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

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	symbol_c *call_param_value,  *param_type;

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	identifier_c *param_name;

   117

	function_param_iterator_c       fp_iterator(f_decl);

   118

	function_call_param_iterator_c fcp_iterator(f_call);

   119

	int extensible_parameter_highest_index = -1;

   120

	unsigned int i;

   121

   122

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

   123

   124

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

   125

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

   126

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

   127

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

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

   129

		 */

   130

		do {

   131

			param_name = fp_iterator.next();

   132

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

   133

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

   134

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

   135

			 * for that code too!

   136

			 */

   137

			if(param_name == NULL) break;

   138

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

   139

   140

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

   141

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

   142

		 * we may be setting this to NULL!

   143

		 */

   144

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

   145

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

   146

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

   147

   148

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

   149

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

   150

		 *       the call 

   151

		 *       call_param_value->accept(*this);

   152

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

   153

		 */

   154

		set_datatype(desired_datatype, call_param_value);

   155

		call_param_value->accept(*this);

   156

   157

		if (NULL != param_name) 

   158

			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   159

				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   160

	}

   161

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

   162

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

   163

	 * of the function call itself!

   164

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

   165

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

   166

	 * output code.

   167

	 */

   168

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

   169

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

   170

}

   171

   172

   173

   174

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

   175

	symbol_c *call_param_value, *call_param_name, *param_type;

   176

	symbol_c *verify_duplicate_param;

   177

	identifier_c *param_name;

   178

	function_param_iterator_c       fp_iterator(f_decl);

   179

	function_call_param_iterator_c fcp_iterator(f_call);

   180

	int extensible_parameter_highest_index = -1;

   181

	identifier_c *extensible_parameter_name;

   182

	unsigned int i;

   183

   184

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

   185

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

   186

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

   187

   188

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

   189

		call_param_value = fcp_iterator.get_current_value();

   190

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

   191

		if (NULL == call_param_value) ERROR;

   192

   193

		/* Find the corresponding parameter in function declaration */

   194

		param_name = fp_iterator.search(call_param_name);

   195

   196

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

   197

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

   198

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

   199

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

   200

		 */

   201

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

   202

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

   203

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

   204

   205

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

   206

		set_datatype(desired_datatype, call_param_value);

   207

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

   208

		call_param_value->accept(*this);

   209

   210

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

   211

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

   212

		if (NULL != param_name) 

   213

			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   214

				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   215

	}

   216

	/* call is compatible! */

   217

   218

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

   219

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

   220

	 * of the function call itself!

   221

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

   222

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

   223

	 * output code.

   224

	 */

   225

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

   226

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

   227

}

   228

   229

   230

/*

   231

typedef struct {

   232

  symbol_c *function_name,

   233

  symbol_c *nonformal_operand_list,

   234

  symbol_c *   formal_operand_list,

   235

   236

  std::vector <symbol_c *> &candidate_functions,  

   237

  symbol_c &*called_function_declaration,

   238

  int      &extensible_param_count

   239

} generic_function_call_t;

   240

*/

   241

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

   242

	/* set the called_function_declaration. */

   243

	fcall_data.called_function_declaration = NULL;

   244

   245

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

   246

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

   247

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

   248

			fcall_data.called_function_declaration = fcall_data.candidate_functions[i];

   249

			break;

   250

		}

   251

	}

   252

   253

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

   254

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

   255

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

   256

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

   257

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

   258

	 *       invocation.

   259

	 */

   260

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

   261

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

   262

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

   263

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

   264

		 * function invocation.

   265

		 */

   266

		fcall_data.called_function_declaration = fcall_data.candidate_functions[0];

   267

	}

   268

   269

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

   270

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

   271

	 * We simply give up!

   272

	 */

   273

	if (NULL == fcall_data.called_function_declaration)

   274

		return;

   275

   276

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

   277

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

   278

   279

	return;

   280

}

   281

   282

   283

   284

   285

/* narrow implicit FB call in IL.

   286

 * e.g.  CLK ton_var

   287

 *        CU counter_var

   288

 *

   289

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

   290

 * the visit(il_fb_call_c *) method handle it!

   291

 */

   292

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

   293

   294

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

   295

	if (NULL != il_operand) {

   296

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

   297

		set_datatype(called_fb_declaration, il_operand);

   298

		il_operand->accept(*this);

   299

	}

   300

	symbol_c *fb_decl = il_operand->datatype;

   301

   302

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

   303

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

   304

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

   305

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

   306

		 */

   307

		return NULL;

   308

	}

   309

   310

	if (NULL == fb_decl) {

   311

		/* the il_operand is a not FB instance */

   312

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

   313

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

   314

		set_datatype_in_prev_il_instructions(il_instruction->datatype, fake_prev_il_instruction);

   315

		return NULL;

   316

	}

   317

   318

   319

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

   320

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

   321

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

   322

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

   323

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

   324

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

   325

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

   326

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

   327

	 */

   328

printf("XX::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  fake_prev_il_instruction->candidate_datatypes.size() = %d\n",fake_prev_il_instruction->candidate_datatypes.size());

   329

printf("XX::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  fake_prev_il_instruction->candidate_datatypes[0] = %p\n",fake_prev_il_instruction->candidate_datatypes[0]);

   330

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

   331

printf("XX::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.candidate_datatypes.size() = %d\n",param_value.candidate_datatypes.size());

   332

printf("XX::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.candidate_datatypes[0] = %p\n",param_value.candidate_datatypes[0]);

   333

printf("00::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  search_constant_type::time_type_name = %p\n", &search_constant_type_c::time_type_name);

   334

printf("00::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  search_constant_type::invalid_type_name = %p\n", &search_constant_type_c::invalid_type_name);

   335

   336

printf("11::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.datatype = %p\n", param_value.datatype);

   337

	identifier_c variable_name(param_name);

   338

	// SYM_REF1(il_assign_operator_c, variable_name)

   339

	il_assign_operator_c il_assign_operator(&variable_name);  

   340

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

   341

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

   342

	il_param_list_c il_param_list;

   343

	il_param_list.add_element(&il_param_assignment);

   344

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

   345

	CAL_operator_c CAL_operator;

   346

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

   347

printf("22::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.datatype = %p\n", param_value.datatype);

   348

   349

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

   350

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

   351

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

   352

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

   353

	 *

   354

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

   355

	 * correctly set up the il_fb_call.datatype variable!

   356

	 */

   357

// 	copy_candidate_datatype_list(il_instruction/*from*/, &il_fb_call/*to*/);

   358

	il_fb_call.called_fb_declaration = called_fb_declaration;

   359

	il_fb_call.accept(*this);

   360

printf("33::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.datatype = %p\n", param_value.datatype);

   361

   362

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

   363

	/* NOTE:

   364

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

   365

	 * is actually the prev_il_instruction.

   366

	 * 

   367

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

   368

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

   369

	 *

   370

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

   371

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

   372

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

   373

	 * and we set it to invalid_type_name.

   374

	 *

   375

	 * However, we only do that if:

   376

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

   377

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

   378

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

   379

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

   380

	 *     FB call must be left unchanged!

   381

	 */

   382

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

   383

printf("44::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.datatype = %p\n", param_value.datatype);

   384

		set_datatype_in_prev_il_instructions(param_value.datatype, fake_prev_il_instruction);

   385

	} else {

   386

printf("55::narrow_candidate_datatypes_c::narrow_implicit_il_fb_call():  param_value.datatype = %p\n", param_value.datatype);

   387

		set_datatype_in_prev_il_instructions(&search_constant_type_c::invalid_type_name, fake_prev_il_instruction);

   388

	}

   389

	return NULL;

   390

}

   391

   392

   393

/* a helper function... */

   394

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

   395

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

   396

	 *       in the code.

   397

	 */

   398

	if (symbol == NULL) return NULL;

   399

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

   400

}

   401

   402

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

   403

/* B 1.2 - Constants */

   404

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

   405

   406

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

   407

/* B 1.3 - Data types */

   408

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

   409

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

   410

/* B 1.3.3 - Derived data types */

   411

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

   412

/*  signed_integer DOTDOT signed_integer */

   413

// SYM_REF2(subrange_c, lower_limit, upper_limit)

   414

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

   415

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

   416

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

   417

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

   418

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

   419

	return NULL;

   420

}

   421

   422

/* simple_specification ASSIGN constant */

   423

// SYM_REF2(simple_spec_init_c, simple_specification, constant)

   424

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

   425

	symbol_c *datatype = base_type(symbol->simple_specification); 

   426

	if (NULL != symbol->constant) {

   427

		int typeoffset = search_in_candidate_datatype_list(datatype, symbol->constant->candidate_datatypes);

   428

		if (typeoffset >= 0)

   429

			symbol->constant->datatype = symbol->constant->candidate_datatypes[typeoffset];

   430

	}

   431

	return NULL;

   432

}

   433

   434

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

   435

/* B 1.4 - Variables */

   436

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

   437

   438

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

   439

/* B 1.4.1 - Directly Represented Variables */

   440

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

   441

   442

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

   443

/* B 1.4.2 - Multi-element variables */

   444

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

   445

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

   446

// SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   447

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

   448

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

   449

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

   450

	return NULL;

   451

}

   452

   453

   454

/* subscript_list ',' subscript */

   455

// SYM_LIST(subscript_list_c)

   456

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

   457

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

   458

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

   459

			if (is_ANY_INT_type(symbol->elements[i]->candidate_datatypes[k]))

   460

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

   461

		}

   462

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

   463

	}

   464

	return NULL;  

   465

}

   466

   467

   468

   469

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

   470

/* B 1.5 Program organization units */

   471

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

   472

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

   473

/* B 1.5.1 Functions */

   474

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

   475

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

   476

	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);

   477

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

   478

	if (debug) printf("Narrowing candidate data types list in body of function %s\n", ((token_c *)(symbol->derived_function_name))->value);

   479

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

   480

	delete search_varfb_instance_type;

   481

	search_varfb_instance_type = NULL;

   482

	return NULL;

   483

}

   484

   485

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

   486

/* B 1.5.2 Function blocks */

   487

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

   488

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

   489

	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);

   490

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

   491

	if (debug) printf("Narrowing candidate data types list in body of FB %s\n", ((token_c *)(symbol->fblock_name))->value);

   492

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

   493

	delete search_varfb_instance_type;

   494

	search_varfb_instance_type = NULL;

   495

	return NULL;

   496

}

   497

   498

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

   499

/* B 1.5.3 Programs */

   500

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

   501

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

   502

	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);

   503

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

   504