1 /*

     2  *  matiec - a compiler for the programming languages defined in IEC 61131-3

     3  *

     4  *  Copyright (C) 2009-2012  Mario de Sousa (msousa@fe.up.pt)

     5  *  Copyright (C) 2012       Manuele Conti  (conti.ma@alice.it)

     6  *

     7  *

     8  *  This program is free software: you can redistribute it and/or modify

     9  *  it under the terms of the GNU General Public License as published by

    10  *  the Free Software Foundation, either version 3 of the License, or

    11  *  (at your option) any later version.

    12  *

    13  *  This program is distributed in the hope that it will be useful,

    14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of

    15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    16  *  GNU General Public License for more details.

    17  *

    18  *  You should have received a copy of the GNU General Public License

    19  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.

    20  *

    21  *

    22  * This code is made available on the understanding that it will not be

    23  * used in safety-critical situations without a full and competent review.

    24  */

    25 

    26 /*

    27  * An IEC 61131-3 compiler.

    28  *

    29  * Based on the

    30  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

    31  *

    32  */

    33 

    34 #include <vector>

    35 #include "../absyntax_utils/absyntax_utils.hh"

    36 #include "datatype_functions.hh"

    37 

    38 

    39 /* Expressions on the left hand side of assignment statements have aditional restrictions on their datatype.

    40  * For example, they cannot be literals, CONSTANT type variables, function invocations, etc...

    41  * This class wil do those checks.

    42  * 

    43  * Note that assignment may also be done when passing variables to OUTPUT or IN_OUT function parameters,so we check those too.

    44  */

    45 

    46 

    47 

    48 class lvalue_check_c: public iterator_visitor_c {

    49 

    50   private:

    51     search_varfb_instance_type_c *search_varfb_instance_type;

    52     search_var_instance_decl_c *search_var_instance_decl;

    53     search_base_type_c search_base_type;

    54     int error_count;

    55     int current_display_error_level;

    56     std::vector <token_c *> control_variables;

    57     symbol_c *current_il_operand;

    58 

    59     void verify_is_lvalue              (symbol_c *lvalue);

    60     void check_assignment_to_controlvar(symbol_c *lvalue);

    61     void check_assignment_to_output    (symbol_c *lvalue);

    62     void check_assignment_to_constant  (symbol_c *lvalue);

    63     void check_assignment_to_expression(symbol_c *lvalue);

    64     void check_formal_call   (symbol_c *f_call, symbol_c *f_decl);

    65     void check_nonformal_call(symbol_c *f_call, symbol_c *f_decl);

    66 

    67 

    68   public:

    69     lvalue_check_c(symbol_c *ignore);

    70     virtual ~lvalue_check_c(void);

    71     int get_error_count();

    72 

    73     /**************************************/

    74     /* B 1.5 - Program organisation units */

    75     /**************************************/

    76     /***********************/

    77     /* B 1.5.1 - Functions */

    78     /***********************/

    79     void *visit(function_declaration_c *symbol);

    80 

    81     /*****************************/

    82     /* B 1.5.2 - Function blocks */

    83     /*****************************/

    84     void *visit(function_block_declaration_c *symbol);

    85 

    86     /**********************/

    87     /* B 1.5.3 - Programs */

    88     /**********************/

    89     void *visit(program_declaration_c *symbol);

    90 

    91     /****************************************/

    92     /* B.2 - Language IL (Instruction List) */

    93     /****************************************/

    94     /***********************************/

    95     /* B 2.1 Instructions and Operands */

    96     /***********************************/

    97     void *visit(il_instruction_c *symbol);

    98     void *visit(il_simple_operation_c *symbol);

    99     void *visit(il_function_call_c *symbol);

   100     void *visit(il_fb_call_c *symbol);

   101     void *visit(il_formal_funct_call_c *symbol);

   102 

   103     /*******************/

   104     /* B 2.2 Operators */

   105     /*******************/

   106     void *visit(ST_operator_c *symbol);

   107     void *visit(STN_operator_c *symbol);

   108     void *visit(S_operator_c *symbol);

   109     void *visit(R_operator_c *symbol);

   110 

   111     /***************************************/

   112     /* B.3 - Language ST (Structured Text) */

   113     /***************************************/

   114     /***********************/

   115     /* B 3.1 - Expressions */

   116     /***********************/

   117     void *visit(function_invocation_c *symbol);

   118 

   119     /*********************************/

   120     /* B 3.2.1 Assignment Statements */

   121     /*********************************/

   122     void *visit(assignment_statement_c *symbol);

   123 

   124     /*****************************************/

   125     /* B 3.2.2 Subprogram Control Statements */

   126     /*****************************************/

   127     void *visit(fb_invocation_c *symbol);

   128 

   129     /********************************/

   130     /* B 3.2.4 Iteration Statements */

   131     /********************************/

   132     void *visit(for_statement_c *symbol);

   133 

   134 }; /* lvalue_check_c */

   135 

   136 

   137 

   138 

   139 

   140 

   141