/*
* matiec - a compiler for the programming languages defined in IEC 61131-3
*
* Copyright (C) 2009-2012 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)
*
*/
/*
* Array Range Checking:
* - Check whether array subscript values fall within the allowed range.
* Note that for the checking of subscript values to work correctly, we need to have constant folding working too:
* array_var[8 + 99] can not be checked without constant folding.
*/
#include "array_range_check.hh"
#include <limits> // required for std::numeric_limits<XXX>
#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 GET_CVALUE(dtype, symbol) ((symbol)->const_value._##dtype.value)
#define VALID_CVALUE(dtype, symbol) (symbol_c::cs_const_value == (symbol)->const_value._##dtype.status)
/* The cmp_unsigned_signed function compares two numbers u and s.
* It returns an integer indicating the relationship between the numbers:
* - A zero value indicates that both numbers are equal.
* - A value greater than zero indicates that numbers does not match and
* first has a greater value.
* - A value less than zero indicates that numbers does not match and
* first has a lesser value.
*/
static inline int cmp_unsigned_signed(const uint64_t u, const int64_t s) {
const uint64_t INT64_MAX_uvar = INT64_MAX;
if (u <= INT64_MAX_uvar)
return ((int64_t)u - s);
return -1;
}
array_range_check_c::array_range_check_c(symbol_c *ignore) {
error_count = 0;
current_display_error_level = 0;
}
array_range_check_c::~array_range_check_c(void) {
}
int array_range_check_c::get_error_count() {
return error_count;
}
void array_range_check_c::check_dimension_count(array_variable_c *symbol) {
int dimension_count;
symbol_c *var_decl;
var_decl = search_varfb_instance_type->get_basetype_decl(symbol->subscripted_variable);
array_dimension_iterator_c array_dimension_iterator(var_decl);
for (dimension_count = 0; NULL != array_dimension_iterator.next(); dimension_count++);
if (dimension_count != ((list_c *)symbol->subscript_list)->n)
STAGE3_ERROR(0, symbol, symbol, "Number of subscripts/indexes does not match the number of subscripts/indexes in the array's declaration (array has %d indexes)", dimension_count);
}
void array_range_check_c::check_bounds(array_variable_c *symbol) {
list_c *l; /* the subscript_list */
symbol_c *var_decl;
l = (list_c *)symbol->subscript_list;
var_decl = search_varfb_instance_type->get_basetype_decl(symbol->subscripted_variable);
array_dimension_iterator_c array_dimension_iterator(var_decl);
for (int i = 0; i < l->n; i++) {
subrange_c *dimension = array_dimension_iterator.next();
/* mismatch between number of indexes/subscripts. This error will be caught in check_dimension_count() so we ignore it. */
if (NULL == dimension)
return;
/* Check lower limit */
if ( VALID_CVALUE( int64, l->elements[i]) && VALID_CVALUE( int64, dimension->lower_limit))
if ( GET_CVALUE( int64, l->elements[i]) < GET_CVALUE( int64, dimension->lower_limit) )
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
if ( VALID_CVALUE( int64, l->elements[i]) && VALID_CVALUE(uint64, dimension->lower_limit))
if ( cmp_unsigned_signed( GET_CVALUE(uint64, dimension->lower_limit), GET_CVALUE( int64, l->elements[i])) > 0 )
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
if ( VALID_CVALUE(uint64, l->elements[i]) && VALID_CVALUE(uint64, dimension->lower_limit))
if ( GET_CVALUE(uint64, l->elements[i]) < GET_CVALUE(uint64, dimension->lower_limit))
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
if ( VALID_CVALUE(uint64, l->elements[i]) && VALID_CVALUE( int64, dimension->lower_limit))
if ( cmp_unsigned_signed(GET_CVALUE(uint64, l->elements[i]), GET_CVALUE( int64, dimension->lower_limit)) < 0 )
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
/* Repeat the same check, now for upper limit */
if ( VALID_CVALUE( int64, l->elements[i]) && VALID_CVALUE( int64, dimension->upper_limit))
if ( GET_CVALUE( int64, l->elements[i]) > GET_CVALUE( int64, dimension->upper_limit))
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
if ( VALID_CVALUE( int64, l->elements[i]) && VALID_CVALUE(uint64, dimension->upper_limit))
if ( cmp_unsigned_signed( GET_CVALUE(uint64, dimension->upper_limit), GET_CVALUE( int64, l->elements[i])) < 0 )
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
if ( VALID_CVALUE(uint64, l->elements[i]) && VALID_CVALUE(uint64, dimension->upper_limit))
if ( GET_CVALUE(uint64, l->elements[i]) > GET_CVALUE(uint64, dimension->upper_limit))
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
if ( VALID_CVALUE(uint64, l->elements[i]) && VALID_CVALUE( int64, dimension->upper_limit))
if ( cmp_unsigned_signed(GET_CVALUE(uint64, l->elements[i]), GET_CVALUE( int64, dimension->upper_limit)) < 0 )
{STAGE3_ERROR(0, symbol, symbol, "Array access out of bounds."); continue;}
}
}
/*************************/
/* B.1 - Common elements */
/*************************/
/**********************/
/* B.1.3 - Data types */
/**********************/
/********************************/
/* B 1.3.3 - Derived data types */
/********************************/
/* signed_integer DOTDOT signed_integer */
/* dimension will be filled in during stage 3 (array_range_check_c) with the number of elements in this subrange */
// SYM_REF2(subrange_c, lower_limit, upper_limit, unsigned long long int dimension)
void *array_range_check_c::visit(subrange_c *symbol) {
unsigned long long int dimension = 0; // we use unsigned long long instead of uint64_t since it might just happen to be larger than uint64_t in the platform used for compiling this code!!
/* Determine the size of the array... */
if (VALID_CVALUE( int64, symbol->upper_limit) && VALID_CVALUE( int64, symbol->lower_limit)) {
// do the sums in such a way that no overflow is possible... even during intermediate steps used by compiler!
// remember that the result (dimension) is unsigned, while the operands are signed!!
// dimension = GET_CVALUE( int64, symbol->upper_limit) - VALID_CVALUE( int64, symbol->lower_limit);
if (GET_CVALUE( int64, symbol->lower_limit) >= 0) {
dimension = GET_CVALUE( int64, symbol->upper_limit) - GET_CVALUE( int64, symbol->lower_limit);
} else {
dimension = -GET_CVALUE( int64, symbol->lower_limit);
dimension += GET_CVALUE( int64, symbol->upper_limit);
}
} else if (VALID_CVALUE(uint64, symbol->upper_limit) && VALID_CVALUE(uint64, symbol->lower_limit)) {
dimension = GET_CVALUE(uint64, symbol->upper_limit) - GET_CVALUE(uint64, symbol->lower_limit);
} else if (VALID_CVALUE(uint64, symbol->upper_limit) && VALID_CVALUE( int64, symbol->lower_limit)) {
if (GET_CVALUE( int64, symbol->lower_limit) >= 0) {
dimension = GET_CVALUE(uint64, symbol->upper_limit) - GET_CVALUE( int64, symbol->lower_limit);
} else {
unsigned long long int lower_ull;
lower_ull = -GET_CVALUE( int64, symbol->lower_limit);
dimension = GET_CVALUE(uint64, symbol->upper_limit) + lower_ull;
if (dimension < lower_ull)
STAGE3_ERROR(0, symbol, symbol, "Number of elements in array subrange exceeds maximum number of elements (%llu).", std::numeric_limits< unsigned long long int >::max());
}
} else ERROR;
/* correct value for dimension is actually ---> dimension = upper_limit - lower_limit + 1
* Up to now, we have only determined dimension = upper_limit - lower_limit
* We must first check whether this last increment will cause an overflow!
*/
if (dimension == std::numeric_limits< unsigned long long int >::max())
STAGE3_ERROR(0, symbol, symbol, "Number of elements in array subrange exceeds maximum number of elements (%llu).", std::numeric_limits< unsigned long long int >::max());
/* correct value for dimension is actually ---> dimension = upper_limit - lower_limit + 1 */
dimension++;
symbol->dimension = dimension;
return NULL;
}
/* integer '(' [array_initial_element] ')' */
/* array_initial_element may be NULL ! */
// SYM_REF2(array_initial_elements_c, integer, array_initial_element)
void *array_range_check_c::visit(array_initial_elements_c *symbol) {
if (VALID_CVALUE( int64, symbol->integer) && (GET_CVALUE( int64, symbol->integer) < 0))
ERROR; /* the IEC 61131-3 syntax guarantees that this value will never be negative! */
/* TODO: check that the total number of 'initial values' does not exceed the size of the array! */
return NULL;
}
/*********************/
/* B 1.4 - Variables */
/*********************/
/*************************************/
/* B 1.4.2 - Multi-element variables */
/*************************************/
void *array_range_check_c::visit(array_variable_c *symbol) {
check_dimension_count(symbol);
check_bounds(symbol);
return NULL;
}
/**************************************/
/* B 1.5 - Program organisation units */
/**************************************/
/***********************/
/* B 1.5.1 - Functions */
/***********************/
// SYM_REF4(function_declaration_c, derived_function_name, type_name, var_declarations_list, function_body)
void *array_range_check_c::visit(function_declaration_c *symbol) {
symbol->var_declarations_list->accept(*this); // required for visiting subrange_c
search_varfb_instance_type = new search_varfb_instance_type_c(symbol);
// search_var_instance_decl = new search_var_instance_decl_c(symbol);
symbol->function_body->accept(*this);
delete search_varfb_instance_type;
// delete search_var_instance_decl;
search_varfb_instance_type = NULL;
// search_var_instance_decl = NULL;
return NULL;
}
/*****************************/
/* B 1.5.2 - Function blocks */
/*****************************/
// SYM_REF3(function_block_declaration_c, fblock_name, var_declarations, fblock_body)
void *array_range_check_c::visit(function_block_declaration_c *symbol) {
symbol->var_declarations->accept(*this); // required for visiting subrange_c
search_varfb_instance_type = new search_varfb_instance_type_c(symbol);
// search_var_instance_decl = new search_var_instance_decl_c(symbol);
symbol->fblock_body->accept(*this);
delete search_varfb_instance_type;
// delete search_var_instance_decl;
search_varfb_instance_type = NULL;
// search_var_instance_decl = NULL;
return NULL;
}
/**********************/
/* B 1.5.3 - Programs */
/**********************/
// SYM_REF3(program_declaration_c, program_type_name, var_declarations, function_block_body)
void *array_range_check_c::visit(program_declaration_c *symbol) {
symbol->var_declarations->accept(*this); // required for visiting subrange_c
search_varfb_instance_type = new search_varfb_instance_type_c(symbol);
// search_var_instance_decl = new search_var_instance_decl_c(symbol);
symbol->function_block_body->accept(*this);
delete search_varfb_instance_type;
// delete search_var_instance_decl;
search_varfb_instance_type = NULL;
// search_var_instance_decl = NULL;
return NULL;
}