--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/stage3/constant_folding.cc	Tue Jun 05 19:17:29 2012 +0200
@@ -0,0 +1,494 @@
+/*
+ *  matiec - a compiler for the programming languages defined in IEC 61131-3
+ *
+ *  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)
+ *  Copyright (C) 2012       Manuele Conti (conti.ma@alice.it)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * This code is made available on the understanding that it will not be
+ * used in safety-critical situations without a full and competent review.
+ */
+
+/*
+ * An IEC 61131-3 compiler.
+ *
+ * Based on the
+ * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
+ *
+ */
+
+
+/* Determine the value of an ST expression.
+ * Filling in all symbols the correct value.
+ *
+ * For example:
+ *       2 + 3         -> returns constant_value_integer = 5
+ *       22.2 - 5.0    -> returns constant_value_real    = 17.2
+ *       etc...
+ */
+
+#include "constant_folding.hh"
+#include <typeinfo>
+#include <limits>
+#include <math.h> /* required for pow function */
+
+#define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order)   ? (symbol1) : (symbol2))
+#define  LAST_(symbol1, symbol2) (((symbol1)->last_order  > (symbol2)->last_order)    ? (symbol1) : (symbol2))
+
+#define STAGE3_ERROR(error_level, symbol1, symbol2, ...) {                                                                  \
+  if (current_display_error_level >= error_level) {                                                                         \
+    fprintf(stderr, "%s:%d-%d..%d-%d: error: ",                                                                             \
+            FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\
+                                                 LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\
+    fprintf(stderr, __VA_ARGS__);                                                                                           \
+    fprintf(stderr, "\n");                                                                                                  \
+    error_count++;                                                                                                     \
+  }                                                                                                                         \
+}
+
+
+#define STAGE3_WARNING(symbol1, symbol2, ...) {                                                                             \
+    fprintf(stderr, "%s:%d-%d..%d-%d: warning: ",                                                                           \
+            FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\
+                                                 LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\
+    fprintf(stderr, __VA_ARGS__);                                                                                           \
+    fprintf(stderr, "\n");                                                                                                  \
+    warning_found = true;                                                                                                   \
+}
+
+
+
+#define DO_OPER(dtype)\
+    (NULL != symbol->r_exp->const_value_##dtype ) && \
+    (NULL != symbol->l_exp->const_value_##dtype )
+
+
+#define CHECK_OVERFLOW_SUM(a, b, type)\
+	((((std::numeric_limits< type >::max() - a) < (b)) ? 1 : 0) || \
+	 (((std::numeric_limits< type >::min() + a) > (b)) ? 1 : 0))
+
+#define CHECK_OVERFLOW_SUB(a, b, type)\
+	((((std::numeric_limits< type >::max() - a) < (-b)) ? 1 : 0) || \
+	 (((std::numeric_limits< type >::min() + a) > (-b)) ? 1 : 0))
+
+
+
+
+
+constant_folding_c::constant_folding_c(symbol_c *symbol) {
+    error_count = 0;
+    current_display_error_level = 0;
+}
+
+constant_folding_c::~constant_folding_c(void) {
+}
+
+int constant_folding_c::get_error_count() {
+	return error_count;
+}
+
+
+/*********************/
+/* B 1.2 - Constants */
+/*********************/
+/******************************/
+/* B 1.2.1 - Numeric Literals */
+/******************************/
+void *constant_folding_c::visit(real_c *symbol) {
+	double *real_value;
+
+	real_value = (double *)malloc(sizeof(double));
+	sscanf(symbol->value, "%lf", real_value);
+	symbol->const_value_real = real_value;
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(integer_c *symbol) {
+	int64_t *integer_value;
+
+	integer_value = (int64_t *)malloc(sizeof(int64_t));
+	*integer_value = extract_integer_value(symbol);
+	symbol->const_value_integer = integer_value;
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(neg_real_c *symbol) {
+	double *real_value;
+
+	real_value = (double *)malloc(sizeof(double));
+	symbol->exp->accept(*this);
+	if (NULL == symbol->exp->const_value_real)
+		ERROR;
+	*real_value = - *(symbol->exp->const_value_real);
+	symbol->const_value_real = real_value;
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(neg_integer_c *symbol) {
+	int64_t *integer_value;
+
+	integer_value = (int64_t *)malloc(sizeof(int64_t));
+	*integer_value = extract_integer_value(symbol);
+	symbol->const_value_integer = integer_value;
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(binary_integer_c *symbol) {
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(octal_integer_c *symbol) {
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(hex_integer_c *symbol) {
+	int64_t *integer_value;
+
+	integer_value = (int64_t *)malloc(sizeof(int64_t));
+	*integer_value = extract_hex_value(symbol);
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(integer_literal_c *symbol) {
+	int64_t *integer_value;
+
+	symbol->value->accept(*this);
+	if (NULL == symbol->value->const_value_integer) ERROR;
+	*(symbol->const_value_integer) = *(symbol->value->const_value_integer);
+	integer_value = (int64_t *)malloc(sizeof(int64_t));
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(real_literal_c *symbol) {
+	double *real_value;
+
+	real_value = (double *)malloc(sizeof(double));
+	symbol->value->accept(*this);
+	if (NULL == symbol->value->const_value_real)
+		ERROR;
+	*real_value = *(symbol->value->const_value_real);
+	symbol->const_value_real = real_value;
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(bit_string_literal_c *symbol) {
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(boolean_literal_c *symbol) {
+	symbol->value->accept(*this);
+	if (NULL == symbol->value->const_value_bool) ERROR;
+	symbol->const_value_bool = (bool *)malloc(sizeof(bool));
+	*(symbol->const_value_bool) = *(symbol->value->const_value_bool);
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(boolean_true_c *symbol) {
+	symbol->const_value_bool = (bool *)malloc(sizeof(bool));
+	*(symbol->const_value_bool) = true;
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(boolean_false_c *symbol) {
+	symbol->const_value_bool = (bool *)malloc(sizeof(bool));
+	*(symbol->const_value_bool) = false;
+
+	return NULL;
+}
+
+/***************************************/
+/* B.3 - Language ST (Structured Text) */
+/***************************************/
+/***********************/
+/* B 3.1 - Expressions */
+/***********************/
+void *constant_folding_c::visit(or_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(bool)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) || *(symbol->r_exp->const_value_bool);
+	}
+	if (DO_OPER(integer)) {
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) | *(symbol->r_exp->const_value_integer);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(xor_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) ^ *(symbol->r_exp->const_value_integer);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(and_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(bool)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) && *(symbol->r_exp->const_value_bool);
+	}
+	if (DO_OPER(integer)) {
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) & *(symbol->r_exp->const_value_integer);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(equ_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(bool)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) == *(symbol->r_exp->const_value_bool);
+	}
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) == *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) == *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(notequ_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(bool)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_bool) != *(symbol->r_exp->const_value_bool);
+	}
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) != *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) != *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(lt_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) < *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) < *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(gt_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) > *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) > *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(le_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) <= *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) <= *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(ge_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_integer) >= *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = *(symbol->l_exp->const_value_real) >= *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(add_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		if (CHECK_OVERFLOW_SUM(*(symbol->l_exp->const_value_integer), *(symbol->r_exp->const_value_integer), int64_t))
+			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) + *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		if (CHECK_OVERFLOW_SUM(*(symbol->l_exp->const_value_real), *(symbol->r_exp->const_value_real), double))
+			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
+		symbol->const_value_real = (double*) malloc(sizeof(double));
+		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) + *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(sub_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		if (CHECK_OVERFLOW_SUB(*(symbol->l_exp->const_value_integer), *(symbol->r_exp->const_value_integer), int64_t))
+			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) - *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		if (CHECK_OVERFLOW_SUB(*(symbol->l_exp->const_value_real), *(symbol->r_exp->const_value_real), double))
+			STAGE3_ERROR(0, symbol, symbol, "Overflow in constant expression.");
+		symbol->const_value_real = (double*) malloc(sizeof(double));
+		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) - *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(mul_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		if ((*(symbol->l_exp->const_value_integer) == 0) ||
+			(*(symbol->r_exp->const_value_integer) == 0)) {
+			*(symbol->const_value_integer) = 0;
+			return NULL;
+		}
+
+		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) * *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		symbol->const_value_real = (double*) malloc(sizeof(double));
+		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) * *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(div_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		if (*(symbol->r_exp->const_value_integer) == 0)
+			STAGE3_ERROR(0, symbol, symbol, "Division by zero in constant expression.");
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) / *(symbol->r_exp->const_value_integer);
+	}
+	if (DO_OPER(real)) {
+		if (*(symbol->r_exp->const_value_real) == 0)
+			STAGE3_ERROR(0, symbol, symbol, "Division by zero in constant expression.");
+		symbol->const_value_real = (double*) malloc(sizeof(double));
+		*(symbol->const_value_real) = *(symbol->l_exp->const_value_real) / *(symbol->r_exp->const_value_real);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(mod_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if (DO_OPER(integer)) {
+		if (*(symbol->r_exp->const_value_integer) == 0)
+			STAGE3_ERROR(0, symbol, symbol, "Division by zero in constant expression.");
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_integer) = *(symbol->l_exp->const_value_integer) % *(symbol->r_exp->const_value_integer);
+	}
+
+	return NULL;
+}
+
+void *constant_folding_c::visit(power_expression_c *symbol) {
+	symbol->l_exp->accept(*this);
+	symbol->r_exp->accept(*this);
+	if ((NULL != symbol->l_exp->const_value_real) && (NULL != symbol->r_exp->const_value_integer)) {
+		symbol->const_value_real = (double*) malloc(sizeof(double));
+		*(symbol->const_value_real) = pow(*(symbol->l_exp->const_value_real), *(symbol->r_exp->const_value_integer));
+	}
+
+	return NULL;
+}
+void *constant_folding_c::visit(neg_expression_c *symbol) {
+	symbol->exp->accept(*this);
+	if (NULL != symbol->exp->const_value_integer) {
+		symbol->const_value_integer = (int64_t*) malloc(sizeof(int64_t));
+		*(symbol->const_value_integer) = - *(symbol->exp->const_value_integer);
+	}
+	if (NULL != symbol->exp->const_value_real) {
+		symbol->const_value_real = (double*) malloc(sizeof(double));
+		*(symbol->const_value_real) = - *(symbol->exp->const_value_real);
+	}
+	return NULL;
+}
+
+void *constant_folding_c::visit(not_expression_c *symbol) {
+	symbol->exp->accept(*this);
+	if (NULL != symbol->exp->const_value_bool) {
+		symbol->const_value_bool = (bool*) malloc(sizeof(bool));
+		*(symbol->const_value_bool) = !*(symbol->exp->const_value_bool);
+	}
+
+	return NULL;
+}
+
+
+