//===-- Parser.h ------------------------------------------------*- C++ -*-===//
//
//                     The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef KLEE_EXPR_PARSER_H
#define KLEE_EXPR_PARSER_H

#include "klee/Expr.h"

#include <vector>
#include <string>

namespace llvm {
  class MemoryBuffer;
}

namespace klee {
namespace expr {
  // These are the language types we manipulate.
  typedef ref<Expr> ExprHandle;
  typedef UpdateList VersionHandle;
  
  /// Identifier - Wrapper for a uniqued string.
  struct Identifier {
    const std::string Name;

  public:
    Identifier(const std::string _Name) : Name(_Name) {}
  };

  // FIXME: Do we have a use for tracking source locations?

  /// Decl - Base class for top level declarations.
  class Decl {
  public:
    enum DeclKind {
      ArrayDeclKind,
      ExprVarDeclKind,
      VersionVarDeclKind,
      QueryCommandDeclKind,
      
      DeclKindLast = QueryCommandDeclKind,
      VarDeclKindFirst = ExprVarDeclKind,
      VarDeclKindLast = VersionVarDeclKind,
      CommandDeclKindFirst = QueryCommandDeclKind,
      CommandDeclKindLast = QueryCommandDeclKind
    };

  private:
    DeclKind Kind;

  public:
    Decl(DeclKind _Kind);
    virtual ~Decl() {}

    /// getKind - Get the decl kind.
    DeclKind getKind() const { return Kind; }

    /// dump - Dump the AST node to stderr.
    virtual void dump() = 0;

    static bool classof(const Decl *) { return true; }
  };

  /// ArrayDecl - Array declarations.
  ///
  /// For example:
  ///   array obj[] : w32 -> w8 = symbolic
  ///   array obj[32] : w32 -> w8 = { ... }
  class ArrayDecl : public Decl {
  public:
    /// Name - The name of this array.
    const Identifier *Name;

    /// Size - The maximum array size (or 0 if unspecified). Concrete
    /// arrays always are specified with a size.
    const uint64_t Size;

    /// Domain - The width of indices.
    const unsigned Domain;

    /// Range - The width of array contents.
    const unsigned Range;

    /// Root - The root array object defined by this decl.
    const Array *Root;

    /// Contents - The initial contents of the array. The array is
    /// symbolic if no contents are specified. The contained
    /// expressions are guaranteed to be constants.
    const std::vector<ExprHandle> Contents;

  public:
    ArrayDecl(const Identifier *_Name, uint64_t _Size, 
              unsigned _Domain, unsigned _Range,
              const Array *_Root)
      : Decl(ArrayDeclKind), Name(_Name), 
        Size(_Size), Domain(_Domain), Range(_Range), 
        Root(_Root) {
    }

    virtual void dump();

    static bool classof(const Decl *D) {
      return D->getKind() == Decl::ArrayDeclKind;
    }
    static bool classof(const ArrayDecl *) { return true; }
  };

  /// VarDecl - Variable declarations, used to associate names to
  /// expressions or array versions outside of expressions.
  /// 
  /// For example:
  // FIXME: What syntax are we going to use for this? We need it.
  class VarDecl : public Decl {
  public:
    const Identifier *Name;    

    static bool classof(const Decl *D) {
      return (Decl::VarDeclKindFirst <= D->getKind() &&
              D->getKind() <= Decl::VarDeclKindLast);
    }
    static bool classof(const VarDecl *) { return true; }
  };

  /// ExprVarDecl - Expression variable declarations.
  class ExprVarDecl : public VarDecl {
  public:
    ExprHandle Value;

    static bool classof(const Decl *D) {
      return D->getKind() == Decl::ExprVarDeclKind;
    }
    static bool classof(const ExprVarDecl *) { return true; }
  };

  /// VersionVarDecl - Array version variable declarations.
  class VersionVarDecl : public VarDecl {
  public:
    VersionHandle Value;

    static bool classof(const Decl *D) {
      return D->getKind() == Decl::VersionVarDeclKind;
    }
    static bool classof(const VersionVarDecl *) { return true; }
  };

  /// CommandDecl - Base class for language commands.
  class CommandDecl : public Decl {
  public:
    CommandDecl(DeclKind _Kind) : Decl(_Kind) {}

    static bool classof(const Decl *D) {
      return (Decl::CommandDeclKindFirst <= D->getKind() &&
              D->getKind() <= Decl::CommandDeclKindLast);
    }
    static bool classof(const CommandDecl *) { return true; }
  };

  /// QueryCommand - Query commands.
  ///
  /// (query [ ... constraints ... ] expression)
  /// (query [ ... constraints ... ] expression values)
  /// (query [ ... constraints ... ] expression values objects)
  class QueryCommand : public CommandDecl {
  public:
    // FIXME: One issue with STP... should we require the FE to
    // guarantee that these are consistent? That is a cornerstone of
    // being able to do independence. We may want this as a flag, if
    // we are to interface with things like SMT.

    /// Constraints - The list of constraints to assume for this
    /// expression.
    const std::vector<ExprHandle> Constraints;
    
    /// Query - The expression being queried.
    ExprHandle Query;

    /// Values - The expressions for which counterexamples should be
    /// given if the query is invalid.
    const std::vector<ExprHandle> Values;

    /// Objects - Symbolic arrays whose initial contents should be
    /// given if the query is invalid.
    const std::vector<const Array*> Objects;

  public:
    QueryCommand(const std::vector<ExprHandle> &_Constraints,
                 ExprHandle _Query,
                 const std::vector<ExprHandle> &_Values,
                 const std::vector<const Array*> &_Objects
                 )
      : CommandDecl(QueryCommandDeclKind),
        Constraints(_Constraints),
        Query(_Query),
        Values(_Values),
        Objects(_Objects) {}

    virtual void dump();

    static bool classof(const Decl *D) {
      return D->getKind() == QueryCommandDeclKind;
    }
    static bool classof(const QueryCommand *) { return true; }
  };
  
  /// Parser - Public interface for parsing a .pc language file.
  class Parser {
  protected:
    Parser();
  public:
    virtual ~Parser();

    /// SetMaxErrors - Suppress anything beyond the first N errors.
    virtual void SetMaxErrors(unsigned N) = 0;
    
    /// GetNumErrors - Return the number of encountered errors.
    virtual unsigned GetNumErrors() const = 0;

    /// ParseTopLevelDecl - Parse and return a top level declaration,
    /// which the caller assumes ownership of.
    ///
    /// \return NULL indicates the end of the file has been reached.
    virtual Decl *ParseTopLevelDecl() = 0;

    /// CreateParser - Create a parser implementation for the given
    /// MemoryBuffer.
    ///
    /// \arg Name - The name to use in diagnostic messages.
    static Parser *Create(const std::string Name,
                          const llvm::MemoryBuffer *MB);
  };
}
}

#endif