//===--- ParsedTemplate.h - Template Parsing Data Types ---------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

//  This file provides data structures that store the parsed representation of

//  templates.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_SEMA_PARSEDTEMPLATE_H

#define LLVM_CLANG_SEMA_PARSEDTEMPLATE_H

#include "clang/Basic/OperatorKinds.h"

#include "clang/Basic/SourceLocation.h"

#include "clang/Basic/TemplateKinds.h"

#include "clang/Sema/DeclSpec.h"

#include "clang/Sema/Ownership.h"

#include "llvm/ADT/SmallVector.h"

#include <cassert>

#include <cstdlib>

#include <new>

namespace clang {

  /// Represents the parsed form of a C++ template argument.

  class ParsedTemplateArgument {

  public:

    /// Describes the kind of template argument that was parsed.

    enum KindType {

      /// A template type parameter, stored as a type.

      Type,

      /// A non-type template parameter, stored as an expression.

      NonType,

      /// A template template argument, stored as a template name.

      Template

    };

    /// Build an empty template argument.

    ///

    /// This template argument is invalid.

    ParsedTemplateArgument() : Kind(Type), Arg(nullptr) { }

    /// Create a template type argument or non-type template argument.

    ///

    /// \param Arg the template type argument or non-type template argument.

    /// \param Loc the location of the type.

    ParsedTemplateArgument(KindType Kind, void *Arg, SourceLocation Loc)

      : Kind(Kind), Arg(Arg), Loc(Loc) { }

    /// Create a template template argument.

    ///

    /// \param SS the C++ scope specifier that precedes the template name, if

    /// any.

    ///

    /// \param Template the template to which this template template

    /// argument refers.

    ///

    /// \param TemplateLoc the location of the template name.

    ParsedTemplateArgument(const CXXScopeSpec &SS,

                           ParsedTemplateTy Template,

                           SourceLocation TemplateLoc)

      : Kind(ParsedTemplateArgument::Template),

        Arg(Template.getAsOpaquePtr()), SS(SS), Loc(TemplateLoc) {}

    /// Determine whether the given template argument is invalid.

    bool isInvalid() const { return Arg == nullptr; }

    /// Determine what kind of template argument we have.

    KindType getKind() const { return Kind; }

    /// Retrieve the template type argument's type.

    ParsedType getAsType() const {

      assert(Kind == Type && "Not a template type argument");

      return ParsedType::getFromOpaquePtr(Arg);

    }

    /// Retrieve the non-type template argument's expression.

    Expr *getAsExpr() const {

      assert(Kind == NonType && "Not a non-type template argument");

      return static_cast<Expr*>(Arg);

    }

    /// Retrieve the template template argument's template name.

    ParsedTemplateTy getAsTemplate() const {

      assert(Kind == Template && "Not a template template argument");

      return ParsedTemplateTy::getFromOpaquePtr(Arg);

    }

    /// Retrieve the location of the template argument.

    SourceLocation getLocation() const { return Loc; }

    /// Retrieve the nested-name-specifier that precedes the template

    /// name in a template template argument.

    const CXXScopeSpec &getScopeSpec() const {

      assert(Kind == Template &&

             "Only template template arguments can have a scope specifier");

      return SS;

    }

    /// Retrieve the location of the ellipsis that makes a template

    /// template argument into a pack expansion.

    SourceLocation getEllipsisLoc() const {

      assert(Kind == Template &&

             "Only template template arguments can have an ellipsis");

      return EllipsisLoc;

    }

    /// Retrieve a pack expansion of the given template template

    /// argument.

    ///

    /// \param EllipsisLoc The location of the ellipsis.

    ParsedTemplateArgument getTemplatePackExpansion(

                                              SourceLocation EllipsisLoc) const;

  private:

    KindType Kind;

    /// The actual template argument representation, which may be

    /// an \c Sema::TypeTy* (for a type), an Expr* (for an

    /// expression), or an Sema::TemplateTy (for a template).

    void *Arg;

    /// The nested-name-specifier that can accompany a template template

    /// argument.

    CXXScopeSpec SS;

    /// the location of the template argument.

    SourceLocation Loc;

    /// The ellipsis location that can accompany a template template

    /// argument (turning it into a template template argument expansion).

    SourceLocation EllipsisLoc;

  };

  /// Information about a template-id annotation

  /// token.

  ///

  /// A template-id annotation token contains the template name,

  /// template arguments, and the source locations for important

  /// tokens. All of the information about template arguments is allocated

  /// directly after this structure.

  /// A template-id annotation token can also be generated by a type-constraint

  /// construct with no explicit template arguments, e.g. "template<C T>" would

  /// annotate C as a TemplateIdAnnotation with no template arguments (the angle

  /// locations would be invalid in this case).

  struct TemplateIdAnnotation final

      : private llvm::TrailingObjects<TemplateIdAnnotation,

                                      ParsedTemplateArgument> {

    friend TrailingObjects;

    /// TemplateKWLoc - The location of the template keyword.

    /// For e.g. typename T::template Y<U>

    SourceLocation TemplateKWLoc;

    /// TemplateNameLoc - The location of the template name within the

    /// source.

    SourceLocation TemplateNameLoc;

    /// FIXME: Temporarily stores the name of a specialization

    IdentifierInfo *Name;

    /// FIXME: Temporarily stores the overloaded operator kind.

    OverloadedOperatorKind Operator;

    /// The declaration of the template corresponding to the

    /// template-name.

    ParsedTemplateTy Template;

    /// The kind of template that Template refers to. If this is

    /// TNK_Non_template, an error was encountered and diagnosed

    /// when parsing or looking up the template name.

    TemplateNameKind Kind;

    /// The location of the '<' before the template argument

    /// list.

    SourceLocation LAngleLoc;

    /// The location of the '>' after the template argument

    /// list.

    SourceLocation RAngleLoc;

    /// NumArgs - The number of template arguments.

    unsigned NumArgs;

    /// Whether an error was encountered in the template arguments.

    /// If so, NumArgs and the trailing arguments are best-effort.

    bool ArgsInvalid;

    /// Retrieves a pointer to the template arguments

    ParsedTemplateArgument *getTemplateArgs() {

      return getTrailingObjects<ParsedTemplateArgument>();

    }

    /// Creates a new TemplateIdAnnotation with NumArgs arguments and

    /// appends it to List.

    static TemplateIdAnnotation *

    Create(SourceLocation TemplateKWLoc, SourceLocation TemplateNameLoc,

           IdentifierInfo *Name, OverloadedOperatorKind OperatorKind,

           ParsedTemplateTy OpaqueTemplateName, TemplateNameKind TemplateKind,

           SourceLocation LAngleLoc, SourceLocation RAngleLoc,

           ArrayRef<ParsedTemplateArgument> TemplateArgs, bool ArgsInvalid,

           SmallVectorImpl<TemplateIdAnnotation *> &CleanupList) {

      TemplateIdAnnotation *TemplateId = new (llvm::safe_malloc(

          totalSizeToAlloc<ParsedTemplateArgument>(TemplateArgs.size())))

          TemplateIdAnnotation(TemplateKWLoc, TemplateNameLoc, Name,

                               OperatorKind, OpaqueTemplateName, TemplateKind,

                               LAngleLoc, RAngleLoc, TemplateArgs, ArgsInvalid);

      CleanupList.push_back(TemplateId);

      return TemplateId;

    }

    void Destroy() {

      for (ParsedTemplateArgument &A :

           llvm::make_range(getTemplateArgs(), getTemplateArgs() + NumArgs))

        A.~ParsedTemplateArgument();

      this->~TemplateIdAnnotation();

      free(this);

    }

    /// Determine whether this might be a type template.

    bool mightBeType() const {

      return Kind == TNK_Non_template ||

             
Kind == TNK_Type_template1.99M
 ||

             
Kind == TNK_Dependent_template_name8.77k
 ||

             
Kind == TNK_Undeclared_template263
;

    }

    bool hasInvalidName() const { return Kind == TNK_Non_template; }

    bool hasInvalidArgs() const { return ArgsInvalid; }

    bool isInvalid() const { return hasInvalidName() || 
hasInvalidArgs()3.92M
; }

  private:

    TemplateIdAnnotation(const TemplateIdAnnotation &) = delete;

    TemplateIdAnnotation(SourceLocation TemplateKWLoc,

                         SourceLocation TemplateNameLoc, IdentifierInfo *Name,

                         OverloadedOperatorKind OperatorKind,

                         ParsedTemplateTy OpaqueTemplateName,

                         TemplateNameKind TemplateKind,

                         SourceLocation LAngleLoc, SourceLocation RAngleLoc,

                         ArrayRef<ParsedTemplateArgument> TemplateArgs,

                         bool ArgsInvalid) noexcept

        : TemplateKWLoc(TemplateKWLoc), TemplateNameLoc(TemplateNameLoc),

          Name(Name), Operator(OperatorKind), Template(OpaqueTemplateName),

          Kind(TemplateKind), LAngleLoc(LAngleLoc), RAngleLoc(RAngleLoc),

          NumArgs(TemplateArgs.size()), ArgsInvalid(ArgsInvalid) {

      std::uninitialized_copy(TemplateArgs.begin(), TemplateArgs.end(),

                              getTemplateArgs());

    }

    ~TemplateIdAnnotation() = default;

  };

  /// Retrieves the range of the given template parameter lists.

  SourceRange getTemplateParamsRange(TemplateParameterList const *const *Params,

                                     unsigned NumParams);

} // end namespace clang

#endif // LLVM_CLANG_SEMA_PARSEDTEMPLATE_H