/* Template support for compile.

   Copyright (C) 2016, 2017 Free Software Foundation, Inc.

   This file is part of GDB.

   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/>.  */

#ifndef COMPILE_CPLUS_TEMPLATES_H
#define COMPILE_CPLUS_TEMPLATES_H
#include "gdbtypes.h"
#include "cp-support.h"

#include <string>
#include <vector>
#include <unordered_map>
#include <memory>

struct symbol;
struct gcc_cp_template_args;
struct template_symbol;

namespace compile
{
  class function_template_defn;
  class class_template_defn;
  class compile_cplus_instance;

  /* Types used for tracking template definitions.  */
  typedef std::unique_ptr<function_template_defn> function_template_defn_up;
  typedef std::unique_ptr<class_template_defn> class_template_defn_up;
  typedef std::pair<std::string, function_template_defn_up>
    function_template_map_item_t;
  typedef std::unordered_map<std::string, function_template_defn_up>
    function_template_defn_map_t;
  typedef std::pair<std::string, class_template_defn_up>
    class_template_map_item_t;
  typedef std::unordered_map<std::string, class_template_defn_up>
    class_template_defn_map_t;

  /* A base class holding data common to all template definitions.  */

  class template_defn
  {
  public:

    /* Return the declaration name of this definition.  */

    const char *
    decl_name () const
    {
      return m_decl_name.c_str ();
    }

    /* Return the compiler plug-in's decl for this definition.  */

    gcc_decl
    decl () const
    {
      return m_decl;
    }

    /* Set the compiler plug-in's decl for this definition.  */

    void
    set_decl (gcc_decl decl)
    {
      m_decl = decl;
    }

    /* Return the generic string for this template definition.  */

    const std::string
    generic (void) const
    {
      return m_generic;
    }

    /* Return the compiler plug-in's abstract type for the IDX'th
       template parameter.  */

    gcc_type
    parameter_abstract_type (unsigned int idx) const
    {
      return m_abstract_types[idx];
    }

    /* Set the IDX'th template parameter's abstract type.  */

    void
    set_parameter_abstract_type (unsigned int idx, gcc_type type)
    {
      m_abstract_types[idx] = type;
    }

    /* Has this template already been defined in the compiler plug-in?  */

    bool
    defined (void) const
    {
      return m_defined;
    }

    /* Mark this definition as defined in the compiler plug-in.  */

    void
    set_defined (bool val)
    {
      m_defined = val;
    }

    /* Return the ARG_NUM'th template parameter's default value
       or NULL if none was set (or known).  */

    struct symbol *
    default_argument (unsigned int arg_num) const
    {
      return m_default_arguments[arg_num];
    }

    /* Record the value of the ARG_NUM'th template parameter.  */

    void
    set_default_argument (unsigned int arg_num, struct symbol *value)
    {
      m_default_arguments[arg_num] = value;
    }

  protected:

    /* Protected constructor so that no one instantiates this
       type directly.

       DECL_NAME is the declaration name of this template, i.e., it's
       name with no template parameters.  GENERIC is the computed generic
       template definition.  N_PARAMETERS specifies how many template
       parameters this template has.  */

    template_defn (std::string decl_name, std::string generic,
		   unsigned int n_parameters)
      : m_decl_name (decl_name), m_generic (generic),
	m_abstract_types (n_parameters), m_decl (0),
	m_default_arguments (n_parameters), m_defined (false)
    {
    }

  private:

    /* The declaration name of the template, excluding any
       parameters.  */
    std::string m_decl_name;

    /* A string representation of the generic template definition.  */
    std::string m_generic;

    /* The abstract template parameter types.  */
    std::vector<gcc_type> m_abstract_types;

    /* The decl associated with this template definition.  */
    gcc_decl m_decl;

    /* A list of default values for the parameters of this template.  */
    std::vector<struct symbol *> m_default_arguments;

    /* Has this template already been defined?  This is a necessary evil
       since we have to traverse over all hash table entries.  */
    bool m_defined;
  };

  /* A function template definition.  */

  class function_template_defn
    : public template_defn
  {
  public:

    /* Construct a new function template definition with the generic
       string representation GENERIC and demangle INFO, based on the
       concrete instance given by template symbol TSYMBOL.

       If this definition is a method template, PARENT_TYPE is the type
       of the closing class and FIDX and MIDX are the fieldlist and
       method indices, respectively, which describe this method.

       If this definition is not a method template, PARENT_TYPE is NULL
       and FIDX/MIDX are both -1.  */

    function_template_defn (std::string generic,
			    std::unique_ptr<demangle_parse_info> info,
			    const struct template_symbol *tsymbol,
			    struct type *parent_type, int fidx, int midx);

    /* Return the demangle information for this template.  */

    const demangle_parse_info *demangle_info (void) const
    {
      return m_demangle_info.get ();
    }

    /* Return the concrete instance used to define this template.  */

    const struct template_symbol *template_symbol (void) const
    {
      return m_tsymbol;
    }

    /* For method templates, return the type of the enclosing parent type,
       or NULL for non-method templates.  */

    struct type *parent_type (void) const
    {
      return m_parent_type;
    }

    /* For method templates, return the field list index in PARENT_TYPE
       which describes this method.  Return -1 otherwise.  */

    int fidx (void) const
    {
      return m_fidx;
    }

    /* For method templates, return the index of this method into the
       field list (given by fidx()).  Return -1 otherwise.  */

    int midx (void) const
    {
      return m_midx;
    }

  private:

    /* The template symbol used to create this template definition.
       NOTE: Any given template_defn could be associated with any number
       of template instances in the program.

       This field is not const since we will be lazily computing template
       parameter indices for the function's argument and return types.  */

    const struct template_symbol *m_tsymbol;

    /* The parent type or NULL if this does not represent a method.  */

    struct type *m_parent_type;

    /* The fieldlist and method indices for the method or -1 if this template
       definition does not represent a method.  */

    int m_fidx;
    int m_midx;

    /* Demangle tree for the template defining this generic.  */
    std::unique_ptr<demangle_parse_info> m_demangle_info;
  };

  /* A class template definition.  */

  class class_template_defn
    : public template_defn
  {
  public:

    /* A unary function to delete map items.  */

    static void destroy (class_template_map_item_t p);

    /* Construct a new class template definition with the generic
       string representation GENERIC based on the concrete instance
       TYPE.  */

    class_template_defn (std::string decl_name, std::string generic,
			 struct type *type)
      : template_defn (decl_name, generic, TYPE_N_TEMPLATE_ARGUMENTS (type)),
	m_type (type)
    {
    }

    /* Return concrete instance that this template definition was
       based on.  */

    struct type *type (void) const
    {
      return m_type;
    }

  private:

    /* The type used to create this template definition.
       NOTE: Any given template_defn could be associated with any number
       of template instances in the program.  */
    struct type *m_type;
  };

  /* Loop over SYMBOLS, defining any generic template definitions for
     any template symbols in the list.  */

  void define_templates (compile_cplus_instance *instance,
			 VEC (block_symbol_d) *symbols);


  /* Scan TYPE for any new function templates.
     Does not actually emit definitions for any new templates until
     emit_function_template_decls is called.  */

  void scan_type_for_function_templates (compile_cplus_instance *instance,
					 struct type *type);
};
#endif /* COMPILE_CPLUS_TEMPLATES_H  */