conti@564: /*
conti@564:  *  matiec - a compiler for the programming languages defined in IEC 61131-3
conti@564:  *
conti@564:  *  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)
conti@564:  *  Copyright (C) 2012       Manuele Conti (conti.ma@alice.it)
conti@564:  *
conti@564:  *  This program is free software: you can redistribute it and/or modify
conti@564:  *  it under the terms of the GNU General Public License as published by
conti@564:  *  the Free Software Foundation, either version 3 of the License, or
conti@564:  *  (at your option) any later version.
conti@564:  *
conti@564:  *  This program is distributed in the hope that it will be useful,
conti@564:  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
conti@564:  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
conti@564:  *  GNU General Public License for more details.
conti@564:  *
conti@564:  *  You should have received a copy of the GNU General Public License
conti@564:  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
conti@564:  *
conti@564:  *
conti@564:  * This code is made available on the understanding that it will not be
conti@564:  * used in safety-critical situations without a full and competent review.
conti@564:  */
conti@564: 
conti@564: /*
conti@564:  * An IEC 61131-3 compiler.
conti@564:  *
conti@564:  * Based on the
conti@564:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
conti@564:  *
conti@564:  */
conti@564: 
conti@564: 
conti@564: /* Determine the value of an ST expression.
conti@564:  * Filling in all symbols the correct value.
conti@564:  *
conti@564:  * For example:
conti@564:  *       2 + 3         -> returns constant_value_integer = 5
conti@564:  *       22.2 - 5.0    -> returns constant_value_real    = 17.2
conti@564:  *       etc...
conti@564:  */
conti@564: 
conti@564: #include "constant_folding.hh"
conti@564: #include <typeinfo>
conti@564: #include <limits>
conti@564: #include <math.h> /* required for pow function */
msousa@565: #include <stdlib.h> /* required for malloc() */
conti@564: 
conti@564: #define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order)   ? (symbol1) : (symbol2))
conti@564: #define  LAST_(symbol1, symbol2) (((symbol1)->last_order  > (symbol2)->last_order)    ? (symbol1) : (symbol2))
conti@564: 
conti@564: #define STAGE3_ERROR(error_level, symbol1, symbol2, ...) {                                                                  \
conti@564:   if (current_display_error_level >= error_level) {                                                                         \
conti@564:     fprintf(stderr, "%s:%d-%d..%d-%d: error: ",                                                                             \
conti@564:             FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\
conti@564:                                                  LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\
conti@564:     fprintf(stderr, __VA_ARGS__);                                                                                           \
conti@564:     fprintf(stderr, "\n");                                                                                                  \
conti@564:     error_count++;                                                                                                     \
conti@564:   }                                                                                                                         \
conti@564: }
conti@564: 
conti@564: 
conti@564: #define STAGE3_WARNING(symbol1, symbol2, ...) {                                                                             \
conti@564:     fprintf(stderr, "%s:%d-%d..%d-%d: warning: ",                                                                           \
conti@564:             FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\
conti@564:                                                  LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\
conti@564:     fprintf(stderr, __VA_ARGS__);                                                                                           \
conti@564:     fprintf(stderr, "\n");                                                                                                  \
conti@564:     warning_found = true;                                                                                                   \
conti@564: }
conti@564: 
conti@564: 
conti@564: 
msousa@567: 
msousa@567: #define MALLOC(variable, data_type) \
msousa@567:  variable = (data_type *)malloc(sizeof(data_type)); \
msousa@567:  if (variable == NULL) ERROR;
msousa@567: 
msousa@567: 
conti@564: #define DO_OPER(dtype)\
conti@564:     (NULL != symbol->r_exp->const_value_##dtype ) && \
conti@564:     (NULL != symbol->l_exp->const_value_##dtype )
conti@564: 
conti@564: 
conti@564: #define CHECK_OVERFLOW_SUM(a, b, type)\
conti@564: 	((((std::numeric_limits< type >::max() - a) < (b)) ? 1 : 0) || \
conti@564: 	 (((std::numeric_limits< type >::min() + a) > (b)) ? 1 : 0))
conti@564: 
conti@564: #define CHECK_OVERFLOW_SUB(a, b, type)\
conti@564: 	((((std::numeric_limits< type >::max() - a) < (-b)) ? 1 : 0) || \
conti@564: 	 (((std::numeric_limits< type >::min() + a) > (-b)) ? 1 : 0))
conti@564: 
conti@566: #define SYMBOL_BOOL_VALUE (symbol->exp->const_value_bool)
conti@566: #define SYMBOL_REAL_VALUE (symbol->exp->const_value_real)
conti@564: 
conti@564: 
conti@564: 
conti@564: 
conti@564: constant_folding_c::constant_folding_c(symbol_c *symbol) {
conti@564:     error_count = 0;
conti@564:     current_display_error_level = 0;
conti@564: }
conti@564: 
msousa@567: 
conti@564: constant_folding_c::~constant_folding_c(void) {
conti@564: }
conti@564: 
msousa@567: 
conti@564: int constant_folding_c::get_error_count() {
conti@564: 	return error_count;
conti@564: }
conti@564: 
conti@564: 
conti@564: /*********************/
conti@564: /* B 1.2 - Constants */
conti@564: /*********************/
conti@564: /******************************/
conti@564: /* B 1.2.1 - Numeric Literals */
conti@564: /******************************/
conti@564: void *constant_folding_c::visit(real_c *symbol) {
msousa@567: 	MALLOC(symbol->const_value_real, double);
msousa@567: 	*symbol->const_value_real = extract_real_value(symbol);
msousa@567: 
msousa@567: 	return NULL;
msousa@567: }
msousa@567: 
conti@564: 
conti@564: void *constant_folding_c::visit(integer_c *symbol) {
conti@564: 	int64_t *integer_value;
conti@564: 
conti@564: 	integer_value = (int64_t *)malloc(sizeof(int64_t));
conti@564: 	*integer_value = extract_integer_value(symbol);
conti@564: 	symbol->const_value_integer = integer_value;
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(neg_real_c *symbol) {
conti@564: 	symbol->exp->accept(*this);
conti@564: 	if (NULL == symbol->exp->const_value_real)
conti@564: 		ERROR;
conti@566: 	symbol->const_value_real = (double*) malloc(sizeof(double));
conti@566: 	*symbol->const_value_real = - *(symbol->exp->const_value_real);
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(neg_integer_c *symbol) {
conti@564: 	int64_t *integer_value;
conti@564: 
conti@564: 	integer_value = (int64_t *)malloc(sizeof(int64_t));
conti@564: 	*integer_value = extract_integer_value(symbol);
conti@564: 	symbol->const_value_integer = integer_value;
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(binary_integer_c *symbol) {
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(octal_integer_c *symbol) {
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(hex_integer_c *symbol) {
conti@566: 	symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@566: 	*(symbol->const_value_integer) = extract_hex_value(symbol);
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(integer_literal_c *symbol) {
conti@564: 	symbol->value->accept(*this);
conti@564: 	if (NULL == symbol->value->const_value_integer) ERROR;
conti@566: 	symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 	*(symbol->const_value_integer) = *(symbol->value->const_value_integer);
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(real_literal_c *symbol) {
conti@564: 	symbol->value->accept(*this);
conti@566: 	if (NULL == symbol->value->const_value_real) ERROR;
conti@566: 	symbol->const_value_real = (double*) malloc(sizeof(double));
conti@566: 	*symbol->const_value_real =  *(symbol->value->const_value_real);
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(bit_string_literal_c *symbol) {
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(boolean_literal_c *symbol) {
conti@564: 	symbol->value->accept(*this);
conti@564: 	if (NULL == symbol->value->const_value_bool) ERROR;
conti@564: 	symbol->const_value_bool = (bool *)malloc(sizeof(bool));
conti@564: 	*(symbol->const_value_bool) = *(symbol->value->const_value_bool);
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(boolean_true_c *symbol) {
conti@564: 	symbol->const_value_bool = (bool *)malloc(sizeof(bool));
conti@564: 	*(symbol->const_value_bool) = true;
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(boolean_false_c *symbol) {
conti@564: 	symbol->const_value_bool = (bool *)malloc(sizeof(bool));
conti@564: 	*(symbol->const_value_bool) = false;
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
msousa@567: 
conti@564: /***************************************/
conti@564: /* B.3 - Language ST (Structured Text) */
conti@564: /***************************************/
conti@564: /***********************/
conti@564: /* B 3.1 - Expressions */
conti@564: /***********************/
conti@564: void *constant_folding_c::visit(or_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(bool)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) || *(symbol->r_exp->const_value_bool);
conti@564: 	}
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) | *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(xor_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) ^ *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(and_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(bool)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) && *(symbol->r_exp->const_value_bool);
conti@564: 	}
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) & *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(equ_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(bool)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) == *(symbol->r_exp->const_value_bool);
conti@564: 	}
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) == *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) == *(symbol->r_exp->const_value_real);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(notequ_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(bool)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) != *(symbol->r_exp->const_value_bool);
conti@564: 	}
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) != *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) != *(symbol->r_exp->const_value_real);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(lt_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) < *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) < *(symbol->r_exp->const_value_real);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(gt_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) > *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) > *(symbol->r_exp->const_value_real);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(le_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) <= *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) <= *(symbol->r_exp->const_value_real);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(ge_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) >= *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) >= *(symbol->r_exp->const_value_real);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(add_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		if (CHECK_OVERFLOW_SUM(*(symbol->l_exp->const_value_integer), *(symbol->r_exp->const_value_integer), int64_t))
conti@564: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) + *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_real = (double*) malloc(sizeof(double));
conti@564: 		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) + *(symbol->r_exp->const_value_real);
conti@566: 		/*
conti@566: 		 * According to the IEEE standard, NaN value is used as:
conti@566: 		 *   - representation of a number that has underflowed
conti@566: 		 *   - representation of number that has overflowed
conti@566: 		 *   - number is a higher precision format
conti@566: 		 *   - A complex number
conti@566: 		 */
conti@566: 		 if (isnan(*(symbol->const_value_real)))
conti@566: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(sub_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		if (CHECK_OVERFLOW_SUB(*(symbol->l_exp->const_value_integer), *(symbol->r_exp->const_value_integer), int64_t))
conti@564: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) - *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_real = (double*) malloc(sizeof(double));
conti@564: 		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) - *(symbol->r_exp->const_value_real);
conti@566: 		/*
conti@566: 		 * According to the IEEE standard, NaN value is used as:
conti@566: 		 *   - representation of a number that has underflowed
conti@566: 		 *   - representation of number that has overflowed
conti@566: 		 *   - number is a higher precision format
conti@566: 		 *   - A complex number
conti@566: 		 */
conti@566: 		if (isnan(*(symbol->const_value_real)))
conti@566: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(mul_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) * *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		symbol->const_value_real = (double*) malloc(sizeof(double));
conti@564: 		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) * *(symbol->r_exp->const_value_real);
conti@566: 		/*
conti@566: 		 * According to the IEEE standard, NaN value is used as:
conti@566: 		 *   - representation of a number that has underflowed
conti@566: 		 *   - representation of number that has overflowed
conti@566: 		 *   - number is a higher precision format
conti@566: 		 *   - A complex number
conti@566: 		 */
conti@566: 		if (isnan(*(symbol->const_value_real)))
conti@566: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(div_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		if (*(symbol->r_exp->const_value_integer) == 0)
conti@564: 			STAGE3_ERROR(0, symbol, symbol, "Division by zero in constant expression.");
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) / *(symbol->r_exp->const_value_integer);
conti@564: 	}
conti@564: 	if (DO_OPER(real)) {
conti@564: 		if (*(symbol->r_exp->const_value_real) == 0)
conti@564: 			STAGE3_ERROR(0, symbol, symbol, "Division by zero in constant expression.");
conti@564: 		symbol->const_value_real = (double*) malloc(sizeof(double));
conti@564: 		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) / *(symbol->r_exp->const_value_real);
conti@566: 		/*
conti@566: 		 * According to the IEEE standard, NaN value is used as:
conti@566: 		 *   - representation of a number that has underflowed
conti@566: 		 *   - representation of number that has overflowed
conti@566: 		 *   - number is a higher precision format
conti@566: 		 *   - A complex number
conti@566: 		 */
conti@566: 		if (isnan(*(symbol->const_value_real)))
conti@566: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(mod_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if (DO_OPER(integer)) {
conti@564: 		if (*(symbol->r_exp->const_value_integer) == 0)
conti@564: 			STAGE3_ERROR(0, symbol, symbol, "Division by zero in constant expression.");
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) % *(symbol->r_exp->const_value_integer);
conti@566: 
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
conti@564: void *constant_folding_c::visit(power_expression_c *symbol) {
conti@564: 	symbol->l_exp->accept(*this);
conti@564: 	symbol->r_exp->accept(*this);
conti@564: 	if ((NULL != symbol->l_exp->const_value_real) && (NULL != symbol->r_exp->const_value_integer)) {
conti@564: 		symbol->const_value_real = (double*) malloc(sizeof(double));
conti@564: 		*(symbol->const_value_real) = pow(*(symbol->l_exp->const_value_real), *(symbol->r_exp->const_value_integer));
conti@566: 		/*
conti@566: 		 * According to the IEEE standard, NaN value is used as:
conti@566: 		 *   - representation of a number that has underflowed
conti@566: 		 *   - representation of number that has overflowed
conti@566: 		 *   - number is a higher precision format
conti@566: 		 *   - A complex number
conti@566: 		 */
conti@566: 		if (isnan(*(symbol->const_value_real)))
conti@566: 			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
msousa@567: 
msousa@567: 
conti@564: void *constant_folding_c::visit(neg_expression_c *symbol) {
conti@564: 	symbol->exp->accept(*this);
conti@564: 	if (NULL != symbol->exp->const_value_integer) {
conti@564: 		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
conti@564: 		*(symbol->const_value_integer) = - *(symbol->exp->const_value_integer);
conti@564: 	}
conti@564: 	if (NULL != symbol->exp->const_value_real) {
conti@564: 		symbol->const_value_real = (double*) malloc(sizeof(double));
conti@564: 		*(symbol->const_value_real) = - *(symbol->exp->const_value_real);
conti@564: 	}
conti@564: 	return NULL;
conti@564: }
conti@564: 
msousa@567: 
msousa@567: 
conti@564: void *constant_folding_c::visit(not_expression_c *symbol) {
conti@564: 	symbol->exp->accept(*this);
conti@564: 	if (NULL != symbol->exp->const_value_bool) {
conti@564: 		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
conti@564: 		*(symbol->const_value_bool) = !*(symbol->exp->const_value_bool);
conti@564: 	}
conti@564: 
conti@564: 	return NULL;
conti@564: }
conti@564: 
conti@564: 
conti@564: