conti@508: /*
conti@508:  *  matiec - a compiler for the programming languages defined in IEC 61131-3
conti@508:  *
conti@508:  *  Copyright (C) 2009-2012  Mario de Sousa (msousa@fe.up.pt)
conti@508:  *  Copyright (C) 2012       Manuele Conti  (conti.ma@alice.it)
conti@508:  *
conti@508:  *
conti@508:  *  This program is free software: you can redistribute it and/or modify
conti@508:  *  it under the terms of the GNU General Public License as published by
conti@508:  *  the Free Software Foundation, either version 3 of the License, or
conti@508:  *  (at your option) any later version.
conti@508:  *
conti@508:  *  This program is distributed in the hope that it will be useful,
conti@508:  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
conti@508:  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
conti@508:  *  GNU General Public License for more details.
conti@508:  *
conti@508:  *  You should have received a copy of the GNU General Public License
conti@508:  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
conti@508:  *
conti@508:  *
conti@508:  * This code is made available on the understanding that it will not be
conti@508:  * used in safety-critical situations without a full and competent review.
conti@508:  */
conti@508: 
conti@508: /*
conti@508:  * An IEC 61131-3 compiler.
conti@508:  *
conti@508:  * Based on the
conti@508:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
conti@508:  *
conti@508:  */
conti@508: 
conti@508: 
conti@508: #include "lvalue_check.hh"
conti@508: 
conti@508: #define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order)   ? (symbol1) : (symbol2))
conti@508: #define  LAST_(symbol1, symbol2) (((symbol1)->last_order  > (symbol2)->last_order)    ? (symbol1) : (symbol2))
conti@508: 
conti@508: #define STAGE3_ERROR(error_level, symbol1, symbol2, ...) {                                                                  \
conti@508:   if (current_display_error_level >= error_level) {                                                                         \
conti@508:     fprintf(stderr, "%s:%d-%d..%d-%d: error: ",                                                                             \
conti@508:             FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\
conti@508:                                                  LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\
conti@508:     fprintf(stderr, __VA_ARGS__);                                                                                           \
conti@508:     fprintf(stderr, "\n");                                                                                                  \
conti@508:     error_found = true;                                                                                                     \
conti@508:   }                                                                                                                         \
conti@508: }
conti@508: 
conti@508: 
conti@508: #define STAGE3_WARNING(symbol1, symbol2, ...) {                                                                             \
conti@508:     fprintf(stderr, "%s:%d-%d..%d-%d: warning: ",                                                                           \
conti@508:             FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\
conti@508:                                                  LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\
conti@508:     fprintf(stderr, __VA_ARGS__);                                                                                           \
conti@508:     fprintf(stderr, "\n");                                                                                                  \
conti@508:     warning_found = true;                                                                                                   \
conti@508: }
conti@508: 
conti@508: 
conti@508: lvalue_check_c::lvalue_check_c(symbol_c *ignore) {
conti@508: 	error_found = false;
conti@508: }
conti@508: 
conti@508: lvalue_check_c::~lvalue_check_c(void) {
conti@508: }
conti@508: 
conti@508: int lvalue_check_c::get_error_found() {
conti@508: 	return error_found;
conti@508: }
conti@508: 
msousa@509: 
msousa@509: #include <strings.h>
conti@508: /* No writing to iterator variables (used in FOR loops) inside the loop itself */
msousa@509: void lvalue_check_c::check_assignment_to_controlvar(symbol_c *lvalue) {
conti@508: 	for (unsigned int i = 0; i < control_variables.size(); i++) {
conti@508: 		symbolic_variable_c *cvar = (symbolic_variable_c *)control_variables[i];
msousa@509: 		if (strcasecmp(((identifier_c *)((symbolic_variable_c *)lvalue)->var_name)->value, ((identifier_c *)((symbolic_variable_c *)cvar)->var_name)->value) == 0) {
conti@508: 			STAGE3_ERROR(0, lvalue, lvalue, "Assignment to FOR control variable are not be allowed.");
conti@508: 			break;
conti@508: 		}
conti@508: 	}
conti@508: }
conti@508: 
msousa@509: 
conti@508: /* fb_instance.var := ...  is not valid if var is output (not input ??) variable */
msousa@509: void lvalue_check_c::check_assignment_to_output(symbol_c * lvalue) {
msousa@509: 	symbol_c *type_id = search_varfb_instance_type->get_basetype_id(lvalue);
conti@508: 	if (NULL != type_id) {
conti@508: 		function_block_declaration_c *fb_decl = function_block_type_symtable.find_value(type_id);
conti@508: 		if (function_block_type_symtable.end_value() != fb_decl) {
conti@508: 			search_var_instance_decl_c   search_var_instance_decl(fb_decl);
conti@508: 			structured_variable_c * str_var = (structured_variable_c *)lvalue;
conti@508: 			unsigned int vartype = search_var_instance_decl.get_vartype(str_var->field_selector);
conti@508: 			if (vartype == search_var_instance_decl_c::output_vt)
msousa@509: 				STAGE3_ERROR(0, lvalue, lvalue, "Assignment to FB output field variable is not be allowed.");
conti@508: 		}
conti@508: 	}
conti@508: }
conti@508: 
msousa@509: 
conti@508: /*  No writing to CONSTANTs */
msousa@509: void lvalue_check_c::check_assignment_to_constant(symbol_c *lvalue) {
msousa@509: 	unsigned int option = search_var_instance_decl->get_option(lvalue);
conti@508: 	if (option == search_var_instance_decl_c::constant_opt) {
msousa@509: 		STAGE3_ERROR(0, lvalue, lvalue, "Assignment to CONSTANT variables is not be allowed.");
msousa@509: 	}
msousa@509: }
msousa@509: 
msousa@509: 
msousa@509: /*  No assigning values to expressions. */
msousa@509: void lvalue_check_c::check_assignment_to_expression(symbol_c *lvalue) {
msousa@509: 	/* TODO: check whether the lvalue is an expresion! */
msousa@509: 	/* This may occur in function invocations, when passing values (possibly an expression) to one 
msousa@509: 	 * of the function's OUTPUT parameters.
conti@508: 	 */
msousa@509: }
msousa@509: 
msousa@509: 
msousa@509: 
msousa@509: void lvalue_check_c::verify_is_lvalue(symbol_c *lvalue) {
msousa@509: 	check_assignment_to_controlvar(lvalue);
msousa@509: 	check_assignment_to_output(lvalue);
msousa@509: 	check_assignment_to_constant(lvalue);
msousa@509: 	check_assignment_to_expression(lvalue);
msousa@509: }
msousa@509: 
msousa@509: 
msousa@509: 
msousa@509: 
msousa@509: /* check whether all values passed to OUT or IN_OUT parameters are legal lvalues. */
msousa@509: void lvalue_check_c::check_nonformal_call(symbol_c *f_call, symbol_c *f_decl) {
msousa@509:   /* TODO */
msousa@509: }
msousa@509: 
msousa@509:   
msousa@509: /* check whether all values passed to OUT or IN_OUT parameters are legal lvalues. */
msousa@509: void lvalue_check_c::check_formal_call(symbol_c *f_call, symbol_c *f_decl) {
msousa@509: 	/* if data type semantic verification was unable to determine which function is being called,
msousa@509: 	 * then it does not make sense to go ahead and check for lvalues to unknown parameters.
msousa@509: 	 * We simply bug out!
msousa@509: 	 */
msousa@509: 	if (NULL == f_decl) return;
msousa@509: 	
msousa@509: 	symbol_c *call_param_name;
msousa@509: 	function_param_iterator_c       fp_iterator(f_decl);
conti@508: 	function_call_param_iterator_c fcp_iterator(f_call);
msousa@509: 
msousa@509: 	/* Iterating through the formal parameters of the function call */
msousa@509: 	while((call_param_name = fcp_iterator.next_f()) != NULL) {
msousa@509: 
msousa@509: 		/* Obtaining the value being passed in the function call */
msousa@509: 		symbol_c *call_param_value = fcp_iterator.get_current_value();
msousa@509: 		if (NULL == call_param_value) ERROR;
msousa@509: 
msousa@509: 		/* Find the corresponding parameter in function declaration, and it's direction (IN, OUT, IN_OUT) */
msousa@509: 		identifier_c *param_name = fp_iterator.search(call_param_name);
msousa@509: 		function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();
msousa@509: 		
msousa@509: 		/* We only check if 'call_param_value' is a valid lvalue if the value is being passed
msousa@509: 		 * to a valid paramater of the function being called, and that parameter is either OUT or IN_OUT.
msousa@509: 		 */
msousa@509: 		if ((param_name != NULL) && 
msousa@509: 		    ((function_param_iterator_c::direction_out == param_direction) || (function_param_iterator_c::direction_inout == param_direction))) {
msousa@509: 			verify_is_lvalue(call_param_value);
conti@508: 		}
msousa@509: 	}
msousa@509: }
msousa@509: 
msousa@509: 
msousa@509: 
msousa@509: 
conti@508: 
conti@508: 
conti@508: 
conti@508: /**************************************/
conti@508: /* B 1.5 - Program organisation units */
conti@508: /**************************************/
conti@508: /***********************/
conti@508: /* B 1.5.1 - Functions */
conti@508: /***********************/
conti@508: void *lvalue_check_c::visit(function_declaration_c *symbol) {
conti@508: 	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);
conti@508: 	search_var_instance_decl = new search_var_instance_decl_c(symbol);
conti@508: 	symbol->function_body->accept(*this);
conti@508: 	delete search_varfb_instance_type;
conti@508: 	delete search_var_instance_decl;
conti@508: 	search_varfb_instance_type = NULL;
conti@508: 	search_var_instance_decl = NULL;
conti@508: 	return NULL;
conti@508: }
conti@508: 
conti@508: /*****************************/
conti@508: /* B 1.5.2 - Function blocks */
conti@508: /*****************************/
conti@508: void *lvalue_check_c::visit(function_block_declaration_c *symbol) {
conti@508: 	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);
conti@508: 	search_var_instance_decl = new search_var_instance_decl_c(symbol);
conti@508: 	symbol->fblock_body->accept(*this);
conti@508: 	delete search_varfb_instance_type;
conti@508: 	delete search_var_instance_decl;
conti@508: 	search_varfb_instance_type = NULL;
conti@508: 	search_var_instance_decl = NULL;
conti@508: 	return NULL;
conti@508: }
conti@508: 
conti@508: /**********************/
conti@508: /* B 1.5.3 - Programs */
conti@508: /**********************/
conti@508: void *lvalue_check_c::visit(program_declaration_c *symbol) {
conti@508: 	search_varfb_instance_type = new search_varfb_instance_type_c(symbol);
conti@508: 	search_var_instance_decl = new search_var_instance_decl_c(symbol);
conti@508: 	symbol->function_block_body->accept(*this);
conti@508: 	delete search_varfb_instance_type;
conti@508: 	delete search_var_instance_decl;
conti@508: 	search_varfb_instance_type = NULL;
conti@508: 	search_var_instance_decl = NULL;
conti@508: 	return NULL;
conti@508: }
conti@508: 
conti@508: /***************************************/
conti@508: /* B.3 - Language ST (Structured Text) */
conti@508: /***************************************/
conti@508: /***********************/
conti@508: /* B 3.1 - Expressions */
conti@508: /***********************/
msousa@509: // SYM_REF3(function_invocation_c, function_name, formal_param_list, nonformal_param_list, symbol_c *called_function_declaration; int extensible_param_count; std::vector <symbol_c *> candidate_functions;)
conti@508: void *lvalue_check_c::visit(function_invocation_c *symbol) {
msousa@509: 	if (NULL != symbol->formal_param_list)
msousa@509: 		check_formal_call(symbol, symbol->called_function_declaration);
msousa@509: 	if (NULL != symbol->nonformal_param_list)
msousa@509: 		check_nonformal_call(symbol, symbol->called_function_declaration);
conti@508: 	return NULL;
conti@508: }
conti@508: 
conti@508: /*********************************/
conti@508: /* B 3.2.1 Assignment Statements */
conti@508: /*********************************/
conti@508: void *lvalue_check_c::visit(assignment_statement_c *symbol) {
msousa@509: 	verify_is_lvalue(symbol->l_exp);
conti@508: 	/* We call visit r_exp to check function_call */
conti@508: 	symbol->r_exp->accept(*this);
conti@508: 	return NULL;
conti@508: }
conti@508: 
conti@508: /********************************/
conti@508: /* B 3.2.4 Iteration Statements */
conti@508: /********************************/
conti@508: void *lvalue_check_c::visit(for_statement_c *symbol) {
conti@508: 	control_variables.push_back(symbol->control_variable);
conti@508: 	symbol->statement_list->accept(*this);
conti@508: 	control_variables.pop_back();
conti@508: 	return NULL;
conti@508: }
conti@508: 
conti@508: 
conti@508: 
conti@508: 
conti@508: 
conti@508: 
conti@508: