--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/stage3/array_range_check.cc Wed Aug 22 16:46:17 2012 +0200
@@ -0,0 +1,322 @@
+/*
+ * 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;
+}
+
+
+