//===- ParsedAttrInfo.h - Info needed to parse an attribute -----*- 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 defines the ParsedAttrInfo class, which dictates how to

// parse an attribute. This class is the one that plugins derive to

// define a new attribute.

//

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

#ifndef LLVM_CLANG_BASIC_PARSEDATTRINFO_H

#define LLVM_CLANG_BASIC_PARSEDATTRINFO_H

#include "clang/Basic/AttrSubjectMatchRules.h"

#include "clang/Basic/AttributeCommonInfo.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/Support/Registry.h"

#include <climits>

#include <list>

namespace clang {

class Decl;

class LangOptions;

class ParsedAttr;

class Sema;

class Stmt;

class TargetInfo;

struct ParsedAttrInfo {

  /// Corresponds to the Kind enum.

  unsigned AttrKind : 16;

  /// The number of required arguments of this attribute.

  unsigned NumArgs : 4;

  /// The number of optional arguments of this attributes.

  unsigned OptArgs : 4;

  /// The number of non-fake arguments specified in the attribute definition.

  unsigned NumArgMembers : 4;

  /// True if the parsing does not match the semantic content.

  unsigned HasCustomParsing : 1;

  // True if this attribute accepts expression parameter pack expansions.

  unsigned AcceptsExprPack : 1;

  /// True if this attribute is only available for certain targets.

  unsigned IsTargetSpecific : 1;

  /// True if this attribute applies to types.

  unsigned IsType : 1;

  /// True if this attribute applies to statements.

  unsigned IsStmt : 1;

  /// True if this attribute has any spellings that are known to gcc.

  unsigned IsKnownToGCC : 1;

  /// True if this attribute is supported by #pragma clang attribute.

  unsigned IsSupportedByPragmaAttribute : 1;

  /// The syntaxes supported by this attribute and how they're spelled.

  struct Spelling {

    AttributeCommonInfo::Syntax Syntax;

    const char *NormalizedFullName;

  };

  ArrayRef<Spelling> Spellings;

  // The names of the known arguments of this attribute.

  ArrayRef<const char *> ArgNames;

protected:

  constexpr ParsedAttrInfo(AttributeCommonInfo::Kind AttrKind =

                               AttributeCommonInfo::NoSemaHandlerAttribute)

      : AttrKind(AttrKind), NumArgs(0), OptArgs(0), NumArgMembers(0),

        HasCustomParsing(0), AcceptsExprPack(0), IsTargetSpecific(0), IsType(0),

        IsStmt(0), IsKnownToGCC(0), IsSupportedByPragmaAttribute(0) {}

  constexpr ParsedAttrInfo(AttributeCommonInfo::Kind AttrKind, unsigned NumArgs,

                           unsigned OptArgs, unsigned NumArgMembers,

                           unsigned HasCustomParsing, unsigned AcceptsExprPack,

                           unsigned IsTargetSpecific, unsigned IsType,

                           unsigned IsStmt, unsigned IsKnownToGCC,

                           unsigned IsSupportedByPragmaAttribute,

                           ArrayRef<Spelling> Spellings,

                           ArrayRef<const char *> ArgNames)

      : AttrKind(AttrKind), NumArgs(NumArgs), OptArgs(OptArgs),

        NumArgMembers(NumArgMembers), HasCustomParsing(HasCustomParsing),

        AcceptsExprPack(AcceptsExprPack), IsTargetSpecific(IsTargetSpecific),

        IsType(IsType), IsStmt(IsStmt), IsKnownToGCC(IsKnownToGCC),

        IsSupportedByPragmaAttribute(IsSupportedByPragmaAttribute),

        Spellings(Spellings), ArgNames(ArgNames) {}

public:

  virtual ~ParsedAttrInfo() = default;

  /// Check if this attribute has specified spelling.

  bool hasSpelling(AttributeCommonInfo::Syntax Syntax, StringRef Name) const {

    return llvm::any_of(Spellings, [&](const Spelling &S) {

      return (S.Syntax == Syntax && S.NormalizedFullName == Name);

    });

  }

  /// Check if this attribute appertains to D, and issue a diagnostic if not.

  virtual bool diagAppertainsToDecl(Sema &S, const ParsedAttr &Attr,

                                    const Decl *D) const {

    return true;

  }

  /// Check if this attribute appertains to St, and issue a diagnostic if not.

  virtual bool diagAppertainsToStmt(Sema &S, const ParsedAttr &Attr,

                                    const Stmt *St) const {

    return true;

  }

  /// Check if the given attribute is mutually exclusive with other attributes

  /// already applied to the given declaration.

  virtual bool diagMutualExclusion(Sema &S, const ParsedAttr &A,

                                   const Decl *D) const {

    return true;

  }

  /// Check if this attribute is allowed by the language we are compiling.

  virtual bool acceptsLangOpts(const LangOptions &LO) const { return true; }

  /// Check if this attribute is allowed when compiling for the given target.

  virtual bool existsInTarget(const TargetInfo &Target) const { return true; }

  /// Convert the spelling index of Attr to a semantic spelling enum value.

  virtual unsigned

  spellingIndexToSemanticSpelling(const ParsedAttr &Attr) const {

    return UINT_MAX;

  }

  /// Returns true if the specified parameter index for this attribute in

  /// Attr.td is an ExprArgument or VariadicExprArgument, or a subclass thereof;

  /// returns false otherwise.

  virtual bool isParamExpr(size_t N) const { return false; }

  /// Populate Rules with the match rules of this attribute.

  virtual void getPragmaAttributeMatchRules(

      llvm::SmallVectorImpl<std::pair<attr::SubjectMatchRule, bool>> &Rules,

      const LangOptions &LangOpts) const {}

  enum AttrHandling { NotHandled, AttributeApplied, AttributeNotApplied };

  /// If this ParsedAttrInfo knows how to handle this ParsedAttr applied to this

  /// Decl then do so and return either AttributeApplied if it was applied or

  /// AttributeNotApplied if it wasn't. Otherwise return NotHandled.

  virtual AttrHandling handleDeclAttribute(Sema &S, Decl *D,

                                           const ParsedAttr &Attr) const {

    return NotHandled;

  }

  static const ParsedAttrInfo &get(const AttributeCommonInfo &A);

  static ArrayRef<const ParsedAttrInfo *> getAllBuiltin();

};

typedef llvm::Registry<ParsedAttrInfo> ParsedAttrInfoRegistry;

const std::list<std::unique_ptr<ParsedAttrInfo>> &getAttributePluginInstances();

} // namespace clang

#endif // LLVM_CLANG_BASIC_PARSEDATTRINFO_H