/*
 *  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)
 *
 */

/* Determine the value of an constant expression.
 * A reference to the relevant type definition is returned.
 *
 * For example:
 *       2 + 3       -> returns reference 
 *       22.2 - 5    -> returns reference
 *       etc...
 */

#include <vector>
#include "../absyntax_utils/absyntax_utils.hh"



/* For the moment we disable constant propagation algorithm as it is not yet complete, 
 * and due to this is currently brocken and producing incorrect results!
 */
#define DO_CONSTANT_PROPAGATION__ 0



class constant_folding_c : public iterator_visitor_c {
    search_varfb_instance_type_c *search_varfb_instance_type;
    int error_count;
    bool warning_found;
    int current_display_error_level;
    /* Pointer to the previous IL instruction, which contains the current cvalue of the data stored in the IL stack, i.e. the default variable, a.k.a. accumulator */
    symbol_c *prev_il_instruction;
    /* the current IL operand being analyzed */
    symbol_c *il_operand;

  public:
	constant_folding_c(symbol_c *symbol = NULL);
	virtual ~constant_folding_c(void);
	int get_error_count();

  private:
    /*********************/
    /* B 1.2 - Constants */
    /*********************/
    /******************************/
    /* B 1.2.1 - Numeric Literals */
    /******************************/
    void *visit(real_c *symbol);
    void *visit(integer_c *symbol);
    void *visit(neg_real_c *symbol);
    void *visit(neg_integer_c *symbol);
    void *visit(binary_integer_c *symbol);
    void *visit(octal_integer_c *symbol);
    void *visit(hex_integer_c *symbol);
    void *visit(integer_literal_c *symbol);
    void *visit(real_literal_c *symbol);
    void *visit(bit_string_literal_c *symbol);
    void *visit(boolean_literal_c *symbol);
    void *visit(boolean_true_c *symbol);
    void *visit(boolean_false_c *symbol);

    /************************/
    /* B 1.2.3.1 - Duration */
    /********* **************/
    void *visit(fixed_point_c *symbol);

    /*********************/
    /* B 1.4 - Variables */
    /*********************/
    #if DO_CONSTANT_PROPAGATION__
    void *visit(symbolic_variable_c *symbol);
    #endif

    /**********************/
    /* B 1.5.3 - Programs */
    /**********************/
    #if DO_CONSTANT_PROPAGATION__
    void *visit(program_declaration_c *symbol);
    #endif

    /****************************************/
    /* B.2 - Language IL (Instruction List) */
    /****************************************/
    /***********************************/
    /* B 2.1 Instructions and Operands */
    /***********************************/
    // void *visit(instruction_list_c *symbol); /* Not needed, since we inherit from iterator_visitor_c */
    void *visit(il_instruction_c *symbol);
    void *visit(il_simple_operation_c *symbol);
    //void *visit(il_function_call_c *symbol);  /* TODO */
    void *visit(il_expression_c *symbol);
    void *visit(il_jump_operation_c *symbol);
    void *visit(il_fb_call_c *symbol);
    //void *visit(il_formal_funct_call_c *symbol);   /* TODO */
    //void *visit(il_operand_list_c *symbol);  /* Not needed, since we inherit from iterator_visitor_c */
    void *visit(simple_instr_list_c *symbol);
    void *visit(il_simple_instruction_c *symbol);


    /*******************/
    /* B 2.2 Operators */
    /*******************/
    void *visit(   LD_operator_c *symbol);
    void *visit(  LDN_operator_c *symbol);
    void *visit(   ST_operator_c *symbol);
    void *visit(  STN_operator_c *symbol);
    void *visit(  NOT_operator_c *symbol);
    void *visit(    S_operator_c *symbol);
    void *visit(    R_operator_c *symbol);
    void *visit(   S1_operator_c *symbol);
    void *visit(   R1_operator_c *symbol);
    void *visit(  CLK_operator_c *symbol);
    void *visit(   CU_operator_c *symbol);
    void *visit(   CD_operator_c *symbol);
    void *visit(   PV_operator_c *symbol);
    void *visit(   IN_operator_c *symbol);
    void *visit(   PT_operator_c *symbol);
    void *visit(  AND_operator_c *symbol);
    void *visit(   OR_operator_c *symbol);
    void *visit(  XOR_operator_c *symbol);
    void *visit( ANDN_operator_c *symbol);
    void *visit(  ORN_operator_c *symbol);
    void *visit( XORN_operator_c *symbol);
    void *visit(  ADD_operator_c *symbol);
    void *visit(  SUB_operator_c *symbol);
    void *visit(  MUL_operator_c *symbol);
    void *visit(  DIV_operator_c *symbol);
    void *visit(  MOD_operator_c *symbol);
    void *visit(   GT_operator_c *symbol);
    void *visit(   GE_operator_c *symbol);
    void *visit(   EQ_operator_c *symbol);
    void *visit(   LT_operator_c *symbol);
    void *visit(   LE_operator_c *symbol);
    void *visit(   NE_operator_c *symbol);
    void *visit(  CAL_operator_c *symbol);
    void *visit( CALC_operator_c *symbol);
    void *visit(CALCN_operator_c *symbol);
    void *visit(  RET_operator_c *symbol);
    void *visit( RETC_operator_c *symbol);
    void *visit(RETCN_operator_c *symbol);
    void *visit(  JMP_operator_c *symbol);
    void *visit( JMPC_operator_c *symbol);
    void *visit(JMPCN_operator_c *symbol);
    /* Symbol class handled together with function call checks */
    // void *visit(il_assign_operator_c *symbol, variable_name);
    /* Symbol class handled together with function call checks */
    // void *visit(il_assign_operator_c *symbol, option, variable_name);

    /***************************************/
    /* B.3 - Language ST (Structured Text) */
    /***************************************/
    /***********************/
    /* B 3.1 - Expressions */
    /***********************/
    void *visit(    or_expression_c *symbol);
    void *visit(   xor_expression_c *symbol);
    void *visit(   and_expression_c *symbol);
    void *visit(   equ_expression_c *symbol);
    void *visit(notequ_expression_c *symbol);
    void *visit(    lt_expression_c *symbol);
    void *visit(    gt_expression_c *symbol);
    void *visit(    le_expression_c *symbol);
    void *visit(    ge_expression_c *symbol);
    void *visit(   add_expression_c *symbol);
    void *visit(   sub_expression_c *symbol);
    void *visit(   mul_expression_c *symbol);
    void *visit(   div_expression_c *symbol);
    void *visit(   mod_expression_c *symbol);
    void *visit( power_expression_c *symbol);
    void *visit(   neg_expression_c *symbol);
    void *visit(   not_expression_c *symbol);
    //void *visit(function_invocation_c *symbol); /* TODO */

    
    #if DO_CONSTANT_PROPAGATION__
    /*********************************/
    /* B 3.2.1 Assignment Statements */
    /*********************************/
    void *visit(assignment_statement_c *symbol);

    /********************************/
    /* B 3.2.3 Selection Statements */
    /********************************/
    void *visit(if_statement_c *symbol);

    /********************************/
    /* B 3.2.4 Iteration Statements */
    /********************************/
    void *visit(for_statement_c *symbol);
    void *visit(while_statement_c *symbol);
    void *visit(repeat_statement_c *symbol);
    #endif // DO_CONSTANT_PROPAGATION__
};