/*
* 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)
*
*/
/* Do constant folding...
*
* I.e., Determine the value of all expressions in which only constant values (i.e. literals) are used.
* The (constant) result of each operation is stored (annotated) in the respective operation symbol
* (e.g.: add_expression_c) in the abstract syntax tree,
*
* For example:
* 2 + 3 -> the constant value '5' is stored in the add_expression_c symbol.
* 22.2 - 5.0 -> the constant value '17.2' is stored in the add_expression_c symbol.
* etc...
*
*
* NOTE 1
* Some operations and constants can have multiple data types. For example,
* 1 AND 0
* may be either a BOOL, BYTE, WORD or LWORD.
*
* The same happens with
* 1 + 2
* which may be signed (e.g. INT) or unsigned (UINT)
*
* For the above reason, instead of storing a single constant value, we actually store 4:
* - bool
* - uint64
* - int64
* - real64
*
* Additionally, since the result of an operation may result in an overflow, we actually
* store the result inside a struct (defined in absyntax.hh)
*
* ** During stage 3 (semantic analysis/checking) we will be doing constant folding.
* * That algorithm will anotate the abstract syntax tree with the result of operations
* * on literals (i.e. 44 + 55 will store the result 99).
* * Since the same source code (e.g. 1 + 0) may actually be a BOOL or an ANY_INT,
* * or an ANY_BIT, we need to handle all possibilities, and determine the result of the
* * operation assuming each type.
* * For this reason, we have one entry for each possible type, with some expressions
* * having more than one entry filled in!
* **
* typedef enum { cs_undefined, // not defined --> const_value is not valid!
* cs_const_value, // const value is valid
* cs_overflow // result produced overflow or underflow --> const_value is not valid!
* } const_status_t;
*
* typedef struct {
* const_status_t status;
* real64_t value;
* } const_value_real64_t;
* const_value_real64_t *const_value_real64; // when NULL --> UNDEFINED
*
* typedef struct {
* const_status_t status;
* int64_t value;
* } const_value_int64_t;
* const_value_int64_t *const_value_int64; // when NULL --> UNDEFINED
*
* typedef struct {
* const_status_t status;
* uint64_t value;
* } const_value_uint64_t;
* const_value_uint64_t *const_value_uint64; // when NULL --> UNDEFINED
*
* typedef struct {
* const_status_t status;
* bool value;
* } const_value_bool_t;
* const_value_bool_t *const_value_bool; // when NULL --> UNDEFINED
*
*
*
* NOTE 2
* This file does not print out any error messages!
* We cannot really print out error messages when we find an overflow. Since each operation
* (symbol in the absract syntax tree for that operation) will have up to 4 constant results,
* it may happen that some of them overflow, while other do not.
* We must wait for data type checking to determine the exact data type of each expression
* before we can decide whether or not we should print out an overflow error message.
*
* For this reason, this visitor merely annotates the abstract syntax tree, and leaves the
* actuall printing of errors for the print_datatype_errors_c class!
*/
#include "constant_folding.hh"
#include <limits>
#include <math.h> /* required for pow function, and HUGE_VAL, HUGE_VALF, HUGE_VALL */
#include <stdlib.h> /* required for malloc() */
#define __STDC_LIMIT_MACROS /* required for UINT64_MAX, INT64_MAX, INT64_MIN, ... */
#include <stdint.h> /* required for UINT64_MAX, INT64_MAX, INT64_MIN, ... */
#ifndef UINT64_MAX
#define UINT64_MAX (std::numeric_limits< uint64_t >::max())
#endif
#ifndef INT64_MAX
#define INT64_MAX (std::numeric_limits< int64_t >::max())
#endif
#ifndef INT64_MIN
#define INT64_MIN (std::numeric_limits< int64_t >::min())
#endif
#if (real64_t == float)
#define HUGE_VAL64 HUGE_VALF
#elif (real64_t == double)
#define HUGE_VAL64 HUGE_VAL
#elif (real64_t == long_double)
#define HUGE_VAL64 HUGE_VALL
#else
#error Could not determine which data type is being used for real64_t (defined in absyntax.hh). Aborting!
#endif
#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 NEW_CVALUE(dtype, symbol) \
(symbol->const_value_##dtype) = new(symbol_c::const_value_##dtype##_t); \
if ((symbol->const_value_##dtype) == NULL) ERROR; \
(symbol->const_value_##dtype)->status = symbol_c::cs_undefined;
#define SET_CVALUE(dtype, symbol, new_value) ((symbol)->const_value_##dtype->value) = new_value; ((symbol)->const_value_##dtype->status) = symbol_c::cs_const_value;
#define GET_CVALUE(dtype, symbol) ((symbol)->const_value_##dtype->value)
#define SET_OVFLOW(dtype, symbol) ((symbol)->const_value_##dtype->status) = symbol_c::cs_overflow
/* The following test is correct in the presence of a NULL pointer, as the logical evaluation will be suspended as soon as the first condition is false! */
#define VALID_CVALUE(dtype, symbol) ((NULL != (symbol)->const_value_##dtype) && (symbol_c::cs_const_value == (symbol)->const_value_##dtype->status))
#define ISZERO_CVALUE(dtype, symbol) ((VALID_CVALUE(dtype, symbol)) && (GET_CVALUE(dtype, symbol) == 0))
#define DO_BINARY_OPER(dtype, oper, otype)\
if (VALID_CVALUE(dtype, symbol->r_exp) && VALID_CVALUE(dtype, symbol->l_exp)) { \
NEW_CVALUE(otype, symbol); \
SET_CVALUE(otype, symbol, GET_CVALUE(dtype, symbol->l_exp) oper GET_CVALUE(dtype, symbol->r_exp)); \
}
#define DO_UNARY_OPER(dtype, oper, arg)\
if (VALID_CVALUE(dtype, arg)) { \
NEW_CVALUE(dtype, symbol); \
SET_CVALUE(dtype, symbol, oper GET_CVALUE(dtype, arg)); \
}
/* NOTE:
* Most of the conditions to detect overflows on signed and unsigned integer operations were adapted from
* https://www.securecoding.cert.org/confluence/display/seccode/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow?showComments=false
* https://www.securecoding.cert.org/confluence/display/seccode/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap
*/
/* NOTE: If at all possible, all overflow tests are done by pre-condition tests, i.e. tests that
* can be run _before_ the operation is executed, and therefore without accessing the result!
*
* The exception is for real/floating point values, that simply test if the result is NaN (not a number).
*/
/* res = a + b */
static void CHECK_OVERFLOW_uint64_SUM(symbol_c *res, symbol_c *a, symbol_c *b) {
if (!VALID_CVALUE(uint64, res))
return;
/* Test by post-condition: If sum is smaller than either operand => overflow! */
// if (GET_CVALUE(uint64, res) < GET_CVALUE(uint64, a))
/* Test by pre-condition: If (UINT64_MAX - a) < b => overflow! */
if ((UINT64_MAX - GET_CVALUE(uint64, a)) < GET_CVALUE(uint64, b))
SET_OVFLOW(uint64, res);
}
/* res = a - b */
static void CHECK_OVERFLOW_uint64_SUB(symbol_c *res, symbol_c *a, symbol_c *b) {
if (!VALID_CVALUE(uint64, res))
return;
/* Test by post-condition: If diference is larger than a => overflow! */
// if (GET_CVALUE(uint64, res) > GET_CVALUE(uint64, a))
/* Test by pre-condition: if b > a => overflow! */
if (GET_CVALUE(uint64, b) > GET_CVALUE(uint64, a))
SET_OVFLOW(uint64, res);
}
/* res = a * b */
static void CHECK_OVERFLOW_uint64_MUL(symbol_c *res, symbol_c *a, symbol_c *b) {
if (!VALID_CVALUE(uint64, res))
return;
/* Test by pre-condition: If (UINT64_MAX / a) < b => overflow! */
if ((UINT64_MAX / GET_CVALUE(uint64, a)) < GET_CVALUE(uint64, b))
SET_OVFLOW(uint64, res);
}
/* res = a / b */
static void CHECK_OVERFLOW_uint64_DIV(symbol_c *res, symbol_c *a, symbol_c *b) {
if (!VALID_CVALUE(uint64, res))
return;
if (GET_CVALUE(uint64, b) == 0) /* division by zero! */
SET_OVFLOW(uint64, res);
}
/* res = a MOD b */
static void CHECK_OVERFLOW_uint64_MOD(symbol_c *res, symbol_c *a, symbol_c *b) {
if (!VALID_CVALUE(uint64, res))
return;
/* no overflow condition exists, including division by zero, which IEC 61131-3 considers legal for MOD operation! */
if (false)
SET_OVFLOW(uint64, res);
}
/* res = a + b */
static void CHECK_OVERFLOW_int64_SUM(symbol_c *res, symbol_c *a_ptr, symbol_c *b_ptr) {
if (!VALID_CVALUE(int64, res))
return;
int64_t a = GET_CVALUE(int64, a_ptr);
int64_t b = GET_CVALUE(int64, b_ptr);
/* The following test is valid no matter what representation is being used (e.g. two's complement, etc...) */
if (((b > 0) && (a > (INT64_MAX - b)))
|| ((b < 0) && (a < (INT64_MIN - b))))
SET_OVFLOW(int64, res);
}
/* res = a - b */
static void CHECK_OVERFLOW_int64_SUB(symbol_c *res, symbol_c *a_ptr, symbol_c *b_ptr) {
if (!VALID_CVALUE(int64, res))
return;
int64_t a = GET_CVALUE(int64, a_ptr);
int64_t b = GET_CVALUE(int64, b_ptr);
/* The following test is valid no matter what representation is being used (e.g. two's complement, etc...) */
if (((b > 0) && (a < (INT64_MIN + b)))
|| ((b < 0) && (a > (INT64_MAX + b))))
SET_OVFLOW(int64, res);
}
/* res = a * b */
static void CHECK_OVERFLOW_int64_MUL(symbol_c *res, symbol_c *a_ptr, symbol_c *b_ptr) {
if (!VALID_CVALUE(int64, res))
return;
int64_t a = GET_CVALUE(int64, a_ptr);
int64_t b = GET_CVALUE(int64, b_ptr);
if ( ( (a > 0) && (b > 0) && (a > (INT64_MAX / b)))
|| ( (a > 0) && !(b > 0) && (b < (INT64_MIN / a)))
|| (!(a > 0) && (b > 0) && (a < (INT64_MIN / b)))
|| (!(a > 0) && !(b > 0) && (a != 0) && (b < (INT64_MAX / a))))
SET_OVFLOW(int64, res);
}
/* res = a / b */
static void CHECK_OVERFLOW_int64_DIV(symbol_c *res, symbol_c *a_ptr, symbol_c *b_ptr) {
if (!VALID_CVALUE(int64, res))
return;
int64_t a = GET_CVALUE(int64, a_ptr);
int64_t b = GET_CVALUE(int64, b_ptr);
if ((b == 0) || ((a == INT64_MIN) && (b == -1)))
SET_OVFLOW(int64, res);
}
/* res = a MOD b */
static void CHECK_OVERFLOW_int64_MOD(symbol_c *res, symbol_c *a_ptr, symbol_c *b_ptr) {
if (!VALID_CVALUE(int64, res))
return;
int64_t a = GET_CVALUE(int64, a_ptr);
int64_t b = GET_CVALUE(int64, b_ptr);
/* IEC 61131-3 standard says IN1 MOD IN2 must be equivalent to
* IF (IN2 = 0) THEN OUT:=0 ; ELSE OUT:=IN1 - (IN1/IN2)*IN2 ; END_IF
*
* Note that, when IN1 = INT64_MIN, and IN2 = -1, an overflow occurs in the division,
* so although the MOD operation should be OK, acording to the above definition, we actually have an overflow!!
*
* On the other hand, division by 0 is OK!!
*/
if ((a == INT64_MIN) && (b == -1))
SET_OVFLOW(int64, res);
}
/* res = - a */
static void CHECK_OVERFLOW_int64_NEG(symbol_c *res, symbol_c *a_ptr) {
if (!VALID_CVALUE(int64, res))
return;
int64_t a = GET_CVALUE(int64, a_ptr);
if (a == INT64_MIN)
SET_OVFLOW(int64, res);
}
static void CHECK_OVERFLOW_real64(symbol_c *res_ptr) {
if (!VALID_CVALUE(real64, res_ptr))
return;
real64_t res = GET_CVALUE(real64, res_ptr);
/* NaN => underflow, overflow, number is a higher precision format, is a complex number (IEEE standard) */
/* The IEC 61131-3 clearly states in section '2.5.1.5.2 Numerical functions':
* "It is an error if the result of evaluation of one of these [numerical] functions exceeds the range of values
* specified for the data type of the function output, or if division by zero is attempted."
* For this reason, any operation that has as a result a positive or negative inifinity, is also an error!
*/
if ((isnan(res)) || (res == HUGE_VAL64) || (res == -HUGE_VAL64))
SET_OVFLOW(real64, res_ptr);
}
constant_folding_c::constant_folding_c(symbol_c *symbol) {
error_count = 0;
warning_found = false;
current_display_error_level = 0;
/* check whether the platform on which the compiler is being run implements IEC 559 floating point data types. */
symbol_c null_symbol;
if (! (std::numeric_limits<real64_t>::is_iec559) )
STAGE3_WARNING(&null_symbol, &null_symbol, "The platform running the compiler does not implement IEC 60559 floating point numbers. "
"Any error and/or warning messages related to overflow/underflow of the result of operations on REAL/LREAL literals "
"(i.e. constant folding) may themselves be erroneous, although are most probably correct."
"However, more likely is the possible existance of overflow/underflow errors that are not detected.");
}
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) {
bool overflow;
NEW_CVALUE(real64, symbol); SET_CVALUE(real64, symbol, extract_real_value(symbol, &overflow));
if (overflow) SET_OVFLOW(real64, symbol);
return NULL;
}
void *constant_folding_c::visit(integer_c *symbol) {
NEW_CVALUE( int64, symbol); SET_CVALUE( int64, symbol, extract_integer_value(symbol));
NEW_CVALUE(uint64, symbol); SET_CVALUE(uint64, symbol, extract_integer_value(symbol));
return NULL;
}
void *constant_folding_c::visit(neg_real_c *symbol) {
symbol->exp->accept(*this);
DO_UNARY_OPER(real64, -, symbol->exp);
CHECK_OVERFLOW_real64(symbol);
return NULL;
}
/* | '-' integer {$$ = new neg_integer_c($2, locloc(@$));} */
void *constant_folding_c::visit(neg_integer_c *symbol) {
symbol->exp->accept(*this);
DO_UNARY_OPER(int64, -, symbol->exp);
CHECK_OVERFLOW_int64_NEG(symbol, symbol->exp);
return NULL;
}
void *constant_folding_c::visit(binary_integer_c *symbol) {
return NULL;
}
void *constant_folding_c::visit(octal_integer_c *symbol) {
return NULL;
}
void *constant_folding_c::visit(hex_integer_c *symbol) {
NEW_CVALUE( int64, symbol); SET_CVALUE( int64, symbol, extract_hex_value(symbol));
NEW_CVALUE(uint64, symbol); SET_CVALUE(uint64, symbol, extract_hex_value(symbol));
return NULL;
}
/*
integer_literal:
integer_type_name '#' signed_integer {$$ = new integer_literal_c($1, $3, locloc(@$));}
| integer_type_name '#' binary_integer {$$ = new integer_literal_c($1, $3, locloc(@$));}
| integer_type_name '#' octal_integer {$$ = new integer_literal_c($1, $3, locloc(@$));}
| integer_type_name '#' hex_integer {$$ = new integer_literal_c($1, $3, locloc(@$));}
*/
// SYM_REF2(integer_literal_c, type, value)
void *constant_folding_c::visit(integer_literal_c *symbol) {
symbol->value->accept(*this);
DO_UNARY_OPER( int64, /* none */, symbol->value);
DO_UNARY_OPER(uint64, /* none */, symbol->value);
return NULL;
}
void *constant_folding_c::visit(real_literal_c *symbol) {
symbol->value->accept(*this);
DO_UNARY_OPER(real64, /* none */, symbol->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);
DO_UNARY_OPER(bool, /* none */, symbol->value);
return NULL;
}
void *constant_folding_c::visit(boolean_true_c *symbol) {
NEW_CVALUE(bool, symbol); SET_CVALUE(bool, symbol, true);
return NULL;
}
void *constant_folding_c::visit(boolean_false_c *symbol) {
NEW_CVALUE(bool, symbol); SET_CVALUE(bool, symbol, 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);
DO_BINARY_OPER( bool, ||, bool);
DO_BINARY_OPER(uint64, | , bool);
return NULL;
}
void *constant_folding_c::visit(xor_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, ^, bool);
DO_BINARY_OPER(uint64, ^, uint64);
return NULL;
}
void *constant_folding_c::visit(and_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, &&, bool);
DO_BINARY_OPER(uint64, & , uint64);
return NULL;
}
void *constant_folding_c::visit(equ_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, ==, bool);
DO_BINARY_OPER(uint64, ==, bool);
DO_BINARY_OPER( int64, ==, bool);
DO_BINARY_OPER(real64, ==, bool);
return NULL;
}
void *constant_folding_c::visit(notequ_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, !=, bool);
DO_BINARY_OPER(uint64, !=, bool);
DO_BINARY_OPER( int64, !=, bool);
DO_BINARY_OPER(real64, !=, bool);
return NULL;
}
void *constant_folding_c::visit(lt_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, <, bool);
DO_BINARY_OPER(uint64, <, bool);
DO_BINARY_OPER( int64, <, bool);
DO_BINARY_OPER(real64, <, bool);
return NULL;
}
void *constant_folding_c::visit(gt_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, >, bool);
DO_BINARY_OPER(uint64, >, bool);
DO_BINARY_OPER( int64, >, bool);
DO_BINARY_OPER(real64, >, bool);
return NULL;
}
void *constant_folding_c::visit(le_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, <=, bool);
DO_BINARY_OPER(uint64, <=, bool);
DO_BINARY_OPER( int64, <=, bool);
DO_BINARY_OPER(real64, <=, bool);
return NULL;
}
void *constant_folding_c::visit(ge_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER( bool, >=, bool);
DO_BINARY_OPER(uint64, >=, bool);
DO_BINARY_OPER( int64, >=, bool);
DO_BINARY_OPER(real64, >=, bool);
return NULL;
}
void *constant_folding_c::visit(add_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER(uint64, +, uint64); CHECK_OVERFLOW_uint64_SUM(symbol, symbol->l_exp, symbol->r_exp);
DO_BINARY_OPER( int64, +, int64); CHECK_OVERFLOW_int64_SUM (symbol, symbol->l_exp, symbol->r_exp);
DO_BINARY_OPER(real64, +, real64); CHECK_OVERFLOW_real64 (symbol);
return NULL;
}
void *constant_folding_c::visit(sub_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER(uint64, -, uint64); CHECK_OVERFLOW_uint64_SUB(symbol, symbol->l_exp, symbol->r_exp);
DO_BINARY_OPER( int64, -, int64); CHECK_OVERFLOW_int64_SUB (symbol, symbol->l_exp, symbol->r_exp);
DO_BINARY_OPER(real64, -, real64); CHECK_OVERFLOW_real64 (symbol);
return NULL;
}
void *constant_folding_c::visit(mul_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
DO_BINARY_OPER(uint64, *, uint64); CHECK_OVERFLOW_uint64_MUL(symbol, symbol->l_exp, symbol->r_exp);
DO_BINARY_OPER( int64, *, int64); CHECK_OVERFLOW_int64_MUL (symbol, symbol->l_exp, symbol->r_exp);
DO_BINARY_OPER(real64, *, real64); CHECK_OVERFLOW_real64 (symbol);
return NULL;
}
void *constant_folding_c::visit(div_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
if (ISZERO_CVALUE(uint64, symbol->r_exp)) {NEW_CVALUE(uint64, symbol); SET_OVFLOW(uint64, symbol);} else {DO_BINARY_OPER(uint64, /, uint64); CHECK_OVERFLOW_uint64_DIV(symbol, symbol->l_exp, symbol->r_exp);};
if (ISZERO_CVALUE( int64, symbol->r_exp)) {NEW_CVALUE( int64, symbol); SET_OVFLOW( int64, symbol);} else {DO_BINARY_OPER( int64, /, int64); CHECK_OVERFLOW_int64_DIV(symbol, symbol->l_exp, symbol->r_exp);};
if (ISZERO_CVALUE(real64, symbol->r_exp)) {NEW_CVALUE(real64, symbol); SET_OVFLOW(real64, symbol);} else {DO_BINARY_OPER(real64, /, real64); CHECK_OVERFLOW_real64(symbol);};
return NULL;
}
void *constant_folding_c::visit(mod_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
/* IEC 61131-3 standard says IN1 MOD IN2 must be equivalent to
* IF (IN2 = 0) THEN OUT:=0 ; ELSE OUT:=IN1 - (IN1/IN2)*IN2 ; END_IF
*
* Note that, when IN1 = INT64_MIN, and IN2 = -1, an overflow occurs in the division,
* so although the MOD operation should be OK, acording to the above definition, we actually have an overflow!!
*/
if (ISZERO_CVALUE(uint64, symbol->r_exp)) {NEW_CVALUE(uint64, symbol); SET_CVALUE(uint64, symbol, 0);} else {DO_BINARY_OPER(uint64, %, uint64); CHECK_OVERFLOW_uint64_MOD(symbol, symbol->l_exp, symbol->r_exp);};
if (ISZERO_CVALUE( int64, symbol->r_exp)) {NEW_CVALUE( int64, symbol); SET_CVALUE( int64, symbol, 0);} else {DO_BINARY_OPER( int64, %, int64); CHECK_OVERFLOW_int64_MOD(symbol, symbol->l_exp, symbol->r_exp);};
return NULL;
}
void *constant_folding_c::visit(power_expression_c *symbol) {
symbol->l_exp->accept(*this);
symbol->r_exp->accept(*this);
/* NOTE: If the const_value in symbol->r_exp is within the limits of both int64 and uint64, then we do both operations.
* That is OK, as the result should be identicial (we do create an unnecessary CVALUE variable, but who cares?).
* If only one is valid, then that is the oper we will do!
*/
if (VALID_CVALUE(real64, symbol->l_exp) && VALID_CVALUE( int64, symbol->r_exp)) {
NEW_CVALUE(real64, symbol);
SET_CVALUE(real64, symbol, pow(GET_CVALUE(real64, symbol->l_exp), GET_CVALUE( int64, symbol->r_exp)));
}
if (VALID_CVALUE(real64, symbol->l_exp) && VALID_CVALUE(uint64, symbol->r_exp)) {
NEW_CVALUE(real64, symbol);
SET_CVALUE(real64, symbol, pow(GET_CVALUE(real64, symbol->l_exp), GET_CVALUE(uint64, symbol->r_exp)));
}
CHECK_OVERFLOW_real64(symbol);
return NULL;
}
void *constant_folding_c::visit(neg_expression_c *symbol) {
symbol->exp->accept(*this);
DO_UNARY_OPER( int64, -, symbol->exp); CHECK_OVERFLOW_int64_NEG(symbol, symbol->exp);
DO_UNARY_OPER(real64, -, symbol->exp); CHECK_OVERFLOW_real64(symbol);
return NULL;
}
void *constant_folding_c::visit(not_expression_c *symbol) {
symbol->exp->accept(*this);
DO_UNARY_OPER( bool, !, symbol->exp);
DO_UNARY_OPER(uint64, ~, symbol->exp);
return NULL;
}