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/*

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

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 *

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 *  Copyright (C) 2003-2012  Mario de Sousa (msousa@fe.up.pt)

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

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 *

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

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

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

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 *  (at your option) any later version.

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 *

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

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

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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *  GNU General Public License for more details.

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 *

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

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

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 *

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 *

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

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

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 */

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/*

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 * An IEC 61131-3 compiler.

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 *

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 * Based on the

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

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 *

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 */

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/* Declaration sequence is a source code part needed to declare variables.

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 * There are some checks we need to do before start with other analysis:

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 *

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 *   - Check external option redefinition.

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 *   - Check external data type redefinition.

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 *   - Check initial values consistently with the data types of the variables/data types being declared.

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 *   - Check whether a function block uses a CONSTANT qualifier as described in 2.5.2.1.

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 *

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 */

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#include "declaration_check.hh"

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#include "datatype_functions.hh"

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#define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order)   ? (symbol1) : (symbol2))

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#define  LAST_(symbol1, symbol2) (((symbol1)->last_order  > (symbol2)->last_order)    ? (symbol1) : (symbol2))

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#define STAGE3_ERROR(error_level, symbol1, symbol2, ...) {                                                                  \

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  if (current_display_error_level >= error_level) {                                                                         \

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    fprintf(stderr, "%s:%d-%d..%d-%d: error: ",                                                                             \

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            FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\

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                                                 LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\

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    fprintf(stderr, __VA_ARGS__);                                                                                           \

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    fprintf(stderr, "\n");                                                                                                  \

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    error_count++;                                                                                                     \

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  }                                                                                                                         \

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}

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#define STAGE3_WARNING(symbol1, symbol2, ...) {                                                                             \

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    fprintf(stderr, "%s:%d-%d..%d-%d: warning: ",                                                                           \

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            FIRST_(symbol1,symbol2)->first_file, FIRST_(symbol1,symbol2)->first_line, FIRST_(symbol1,symbol2)->first_column,\

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                                                 LAST_(symbol1,symbol2) ->last_line,  LAST_(symbol1,symbol2) ->last_column);\

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    fprintf(stderr, __VA_ARGS__);                                                                                           \

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    fprintf(stderr, "\n");                                                                                                  \

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    warning_found = true;                                                                                                   \

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}

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#include "constant_folding.hh"

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#include <set>

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class check_extern_c: public iterator_visitor_c {

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  public:

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  private:

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    int current_display_error_level;

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    symbol_c *current_pou_decl;

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    symbol_c *current_resource_decl;

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    static std::set<symbol_c *> checked_decl; // A set with all the declarations that have already been checked, so we don't recheck it again!

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  public:

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    static int error_count;

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    check_extern_c(symbol_c *current_pou, symbol_c *current_resource) {

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      current_display_error_level = 0;

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      current_pou_decl      = current_pou;

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      current_resource_decl = current_resource;

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    }

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    ~check_extern_c(void) {}

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    void check_global_decl(symbol_c *p_decl) {

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      if (NULL == current_pou_decl) ERROR;

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      if (checked_decl.find(p_decl) != checked_decl.end()) return; // has already been checked!

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      checked_decl.insert(p_decl);

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      search_var_instance_decl_c search_var_instance_pou_glo_decl(current_pou_decl);

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      search_var_instance_decl_c search_var_instance_res_glo_decl(current_resource_decl);

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      search_var_instance_decl_c search_var_instance_ext_decl(p_decl);

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      function_param_iterator_c  fpi(p_decl);

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      symbol_c *var_name;

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      while((var_name = fpi.next()) != NULL) {            

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        if (fpi.param_direction() == function_param_iterator_c::direction_extref) {

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          /* found an external reference parameter. */

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          symbol_c *ext_decl = search_var_instance_ext_decl.get_decl(var_name);

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          // NOTE: Must check the POU first, and RESOURCE second!

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          symbol_c                                       *glo_decl =  search_var_instance_res_glo_decl.get_decl(var_name);           

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              search_var_instance_decl_c *search_var_instance_glo_decl = &search_var_instance_res_glo_decl;

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          if (NULL == glo_decl) {

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            glo_decl                     =  search_var_instance_pou_glo_decl.get_decl(var_name);

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            search_var_instance_glo_decl = &search_var_instance_pou_glo_decl;

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          }

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          if (NULL == glo_decl) {

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            STAGE3_ERROR(0, ext_decl, ext_decl, "Declaration error. The external variable does not match with any global variable.");

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            continue;

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          }

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          /* Check whether variable's constness (CONSTANT) is compatible.

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           *        VAR_GLOBAL is contant     => VAR_EXTERNAL must also be CONSTANT

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           *        VAR_GLOBAL is not contant => VAR_EXTERNAL may be CONSTANT, or not!

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           */

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          search_var_instance_decl_c::opt_t ext_opt = search_var_instance_ext_decl. get_option(var_name);

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          search_var_instance_decl_c::opt_t glo_opt = search_var_instance_glo_decl->get_option(var_name);

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          if ((glo_opt == search_var_instance_decl_c::constant_opt) && (ext_opt != search_var_instance_decl_c::constant_opt))

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            STAGE3_ERROR(0, glo_decl, glo_decl, "Declaration error. The external variable must be declared as constant, as it maps to a constant global variable.");

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          /* Copy the const_value from the global to the external variable.

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           *   This is actually part of the constant folding algorithm. It is placed here because it needs the extern<->global pairing

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           *   information to run correctly, which is all available right here!

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           */

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          constant_folding_c constant_folding;

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          constant_folding.handle_var_extern_global_pair(var_name /* extern_var */, ext_decl /* extern_decl */, NULL /* global_var */, glo_decl /* global_decl */);

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          /* TODO: Check redefinition data type.

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           *       We need a new class (like search_base_type class) to get type id by variable declaration.

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           *  symbol_c *glo_type = ????;

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           *  symbol_c *ext_type = fpi.param_type();

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           */

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          /* For the moment, we will just use search_base_type_c instead... */

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          symbol_c *glo_type = search_base_type_c::get_basetype_decl(glo_decl);

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          symbol_c *ext_type = search_base_type_c::get_basetype_decl(ext_decl);

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          if (! get_datatype_info_c::is_type_equal(glo_type, ext_type))

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            STAGE3_ERROR(0, ext_decl, ext_decl, "Declaration error.  Data type mismatch between external and global variable declarations.");

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        }

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      }

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    }

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    /********************************/

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    /* B 1.3.3 - Derived data types */

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    /********************************/

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    /*  function_block_type_name ASSIGN structure_initialization */

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    /* structure_initialization -> may be NULL ! */

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    //SYM_REF2(fb_spec_init_c, function_block_type_name, structure_initialization)

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    /* NOTE: This class is only used when declaring FB variables, as in:

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     * name_list ':' function_block_type_name ASSIGN structure_initialization

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     *               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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     *                      fb_spec_init_c                                   

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     * Here, fb_spec_init_c is used whether it is an external, local, or global variable!

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     * Note too that we must also check the datatypes of external and global variables!! 

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     */

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    void *visit(fb_spec_init_c *symbol) {

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      function_block_type_symtable_t::iterator iter = function_block_type_symtable.find(symbol->function_block_type_name);

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      /* stage1_2 guarantees that we are sure to find a declaration in FB or Program symtable. */

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      if (iter == function_block_type_symtable.end())

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        ERROR;

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      iter->second->accept(*this); // iter->second is a fb_decl

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      return NULL;

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    }

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    /*****************************/

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    /* B 1.5.2 - Function Blocks */

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    /*****************************/

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    /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

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    // SYM_REF3(function_block_declaration_c, fblock_name, var_declarations, fblock_body)

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    void *visit(function_block_declaration_c *symbol) {

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      check_global_decl(symbol);

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      /* The following two lines of code are only valid for v3 of IEC 61131-3, that allows VAR_GLOBAL declarations inside FBs!

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       * current_pou_decl = symbol;  

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       * current_resource_decl = NULL;  

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       */

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      /* check if any FB declared as a VAR has any incompatible VAR_EXTERNAL declarations */

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      if (NULL != symbol->var_declarations)

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        symbol->var_declarations->accept(*this);  // This will eventually call the visit(fb_spec_init_c *) method, if any FB are declared here!

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      return NULL;

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    }

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    /******************************************/

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    /* B 1.5.3 - Declaration & Initialisation */

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    /******************************************/

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    /*  PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */

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    // SYM_REF3(program_declaration_c, program_type_name, var_declarations, function_block_body)

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    void *visit(program_declaration_c *symbol) {

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      check_global_decl(symbol);

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      /* The following two lines of code are only valid for v3 of IEC 61131-3, that allows VAR_GLOBAL declarations inside PROGRAMs!

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       * current_pou_decl = symbol;  

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       * current_resource_decl = NULL;  

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       */

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      /* check if any FB declared as a VAR has any incompatible VAR_EXTERNAL declarations */

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      if (NULL != symbol->var_declarations)

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        symbol->var_declarations->accept(*this);  // This will eventually call the visit(fb_spec_init_c *) method, if any FB are declared here!

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      return NULL;

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    }

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};

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int check_extern_c::error_count = 0;

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std::set<symbol_c *> check_extern_c::checked_decl;

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declaration_check_c::declaration_check_c(symbol_c *ignore) {

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  current_display_error_level = 0;

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  current_pou_decl = NULL;

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  current_resource_decl = NULL;

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  error_count = 0;

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}

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declaration_check_c::~declaration_check_c(void) {

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}

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int declaration_check_c::get_error_count() {

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  return check_extern_c::error_count;

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}

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/*****************************/

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/* B 1.5.2 - Function Blocks */

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/*****************************/

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/*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

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// SYM_REF3(function_block_declaration_c, fblock_name, var_declarations, fblock_body)

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void *declaration_check_c::visit(function_block_declaration_c *symbol)

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  {return NULL;} // We only check the declarations that are used to instantiate variables. This is done in the configuration!

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/******************************************/

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/* B 1.5.3 - Declaration & Initialisation */

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/******************************************/

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/*  PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */

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// SYM_REF3(program_declaration_c, program_type_name, var_declarations, function_block_body)

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void *declaration_check_c::visit(program_declaration_c *symbol) 

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  {return NULL;} // We only check the declarations that are used to instantiate variables. This is done in the configuration!

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/********************************/

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/* B 1.7 Configuration elements */

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/********************************/

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/*

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 * CONFIGURATION configuration_name

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 *    optional_global_var_declarations

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 *    (resource_declaration_list | single_resource_declaration)

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 *    optional_access_declarations

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 *    optional_instance_specific_initializations

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 * END_CONFIGURATION

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 */

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//SYM_REF5(configuration_declaration_c, configuration_name, global_var_declarations, resource_declarations, access_declarations, instance_specific_initializations)

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void *declaration_check_c::visit(configuration_declaration_c *symbol) {

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  current_pou_decl = symbol;

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  /* check if any FB declared as a VAR has any incompatible VAR_EXTERNAL declarations */

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  if (NULL != symbol->resource_declarations)

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    symbol->resource_declarations->accept(*this);

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  current_pou_decl = NULL;

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  return NULL;

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}

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/*

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RESOURCE resource_name ON resource_type_name

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   optional_global_var_declarations

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   single_resource_declaration

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END_RESOURCE

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*/

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/* enumvalue_symtable is filled in by enum_declaration_check_c, during stage3 semantic verification, with a list of all enumerated constants declared inside this POU */

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// SYM_REF4(resource_declaration_c, resource_name, resource_type_name, global_var_declarations, resource_declaration, enumvalue_symtable_t enumvalue_symtable;)

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void *declaration_check_c::visit(resource_declaration_c *symbol) {

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  // check if any FB instantiated inside this resource (in a VAR_GLOBAL) has any VAR_EXTERNAL declarations incompatible with the configuration's VAR_GLOBALs

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  check_extern_c check_extern(current_pou_decl, current_resource_decl);

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  symbol->global_var_declarations->accept(check_extern);   

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  // Now check the Programs instantiated in this resource

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  current_resource_decl = symbol;

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  symbol->resource_declaration->accept(*this);

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  current_resource_decl = NULL;  

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  return NULL;

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}

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/*  PROGRAM [RETAIN | NON_RETAIN] program_name [WITH task_name] ':' program_type_name ['(' prog_conf_elements ')'] */

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void *declaration_check_c::visit(program_configuration_c *symbol) {

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  symbol_c *p_decl = NULL;

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  program_type_symtable_t       ::iterator iter_p = program_type_symtable       .find(symbol->program_type_name);

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  function_block_type_symtable_t::iterator iter_f = function_block_type_symtable.find(symbol->program_type_name);

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  if  (iter_p != program_type_symtable       .end())  p_decl = iter_p->second;

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  if  (iter_f != function_block_type_symtable.end())  p_decl = iter_f->second;

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  if ((iter_f != function_block_type_symtable.end()) && (iter_p != program_type_symtable.end())) 

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    ERROR;  // Should never occur! stage1_2 guarantees that the same identifier cannot be re-used.

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  if ((iter_f == function_block_type_symtable.end()) && (iter_p == program_type_symtable.end())) 

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    ERROR;  // Should never occur! stage1_2 guarantees that we are sure to find a declaration in FB or Program symtable.

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  check_extern_c check_extern(current_pou_decl, current_resource_decl);

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  p_decl->accept(check_extern);

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  return NULL;

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}

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