//===--- Specifiers.h - Declaration and Type Specifiers ---------*- 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

//

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

///

/// \file

/// Defines various enumerations that describe declaration and

/// type specifiers.

///

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

#ifndef LLVM_CLANG_BASIC_SPECIFIERS_H

#define LLVM_CLANG_BASIC_SPECIFIERS_H

#include "llvm/ADT/StringRef.h"

#include "llvm/Support/DataTypes.h"

#include "llvm/Support/ErrorHandling.h"

namespace clang {

  /// Define the meaning of possible values of the kind in ExplicitSpecifier.

  enum class ExplicitSpecKind : unsigned {

    ResolvedFalse,

    ResolvedTrue,

    Unresolved,

  };

  /// Define the kind of constexpr specifier.

  enum class ConstexprSpecKind { Unspecified, Constexpr, Consteval, Constinit };

  /// In an if statement, this denotes whether the the statement is

  /// a constexpr or consteval if statement.

  enum class IfStatementKind : unsigned {

    Ordinary,

    Constexpr,

    ConstevalNonNegated,

    ConstevalNegated

  };

  /// Specifies the width of a type, e.g., short, long, or long long.

  enum class TypeSpecifierWidth { Unspecified, Short, Long, LongLong };

  /// Specifies the signedness of a type, e.g., signed or unsigned.

  enum class TypeSpecifierSign { Unspecified, Signed, Unsigned };

  enum class TypeSpecifiersPipe { Unspecified, Pipe };

  /// Specifies the kind of type.

  enum TypeSpecifierType {

    TST_unspecified,

    TST_void,

    TST_char,

    TST_wchar,        // C++ wchar_t

    TST_char8,        // C++20 char8_t (proposed)

    TST_char16,       // C++11 char16_t

    TST_char32,       // C++11 char32_t

    TST_int,

    TST_int128,

    TST_bitint,       // Bit-precise integer types.

    TST_half,         // OpenCL half, ARM NEON __fp16

    TST_Float16,      // C11 extension ISO/IEC TS 18661-3

    TST_Accum,        // ISO/IEC JTC1 SC22 WG14 N1169 Extension

    TST_Fract,

    TST_BFloat16,

    TST_float,

    TST_double,

    TST_float128,

    TST_ibm128,

    TST_bool,         // _Bool

    TST_decimal32,    // _Decimal32

    TST_decimal64,    // _Decimal64

    TST_decimal128,   // _Decimal128

    TST_enum,

    TST_union,

    TST_struct,

    TST_class,        // C++ class type

    TST_interface,    // C++ (Microsoft-specific) __interface type

    TST_typename,     // Typedef, C++ class-name or enum name, etc.

    TST_typeofType,

    TST_typeofExpr,

    TST_decltype,         // C++11 decltype

    TST_underlyingType,   // __underlying_type for C++11

    TST_auto,             // C++11 auto

    TST_decltype_auto,    // C++1y decltype(auto)

    TST_auto_type,        // __auto_type extension

    TST_unknown_anytype,  // __unknown_anytype extension

    TST_atomic,           // C11 _Atomic

#define GENERIC_IMAGE_TYPE(ImgType, Id) TST_##ImgType##_t, // OpenCL image types

#include "clang/Basic/OpenCLImageTypes.def"

    TST_error // erroneous type

  };

  /// Structure that packs information about the type specifiers that

  /// were written in a particular type specifier sequence.

  struct WrittenBuiltinSpecs {

    static_assert(TST_error < 1 << 6, "Type bitfield not wide enough for TST");

    /*DeclSpec::TST*/ unsigned Type  : 6;

    /*DeclSpec::TSS*/ unsigned Sign  : 2;

    /*TypeSpecifierWidth*/ unsigned Width : 2;

    unsigned ModeAttr : 1;

  };

  /// A C++ access specifier (public, private, protected), plus the

  /// special value "none" which means different things in different contexts.

  enum AccessSpecifier {

    AS_public,

    AS_protected,

    AS_private,

    AS_none

  };

  /// The categorization of expression values, currently following the

  /// C++11 scheme.

  enum ExprValueKind {

    /// A pr-value expression (in the C++11 taxonomy)

    /// produces a temporary value.

    VK_PRValue,

    /// An l-value expression is a reference to an object with

    /// independent storage.

    VK_LValue,

    /// An x-value expression is a reference to an object with

    /// independent storage but which can be "moved", i.e.

    /// efficiently cannibalized for its resources.

    VK_XValue

  };

  /// A further classification of the kind of object referenced by an

  /// l-value or x-value.

  enum ExprObjectKind {

    /// An ordinary object is located at an address in memory.

    OK_Ordinary,

    /// A bitfield object is a bitfield on a C or C++ record.

    OK_BitField,

    /// A vector component is an element or range of elements on a vector.

    OK_VectorComponent,

    /// An Objective-C property is a logical field of an Objective-C

    /// object which is read and written via Objective-C method calls.

    OK_ObjCProperty,

    /// An Objective-C array/dictionary subscripting which reads an

    /// object or writes at the subscripted array/dictionary element via

    /// Objective-C method calls.

    OK_ObjCSubscript,

    /// A matrix component is a single element of a matrix.

    OK_MatrixComponent

  };

  /// The reason why a DeclRefExpr does not constitute an odr-use.

  enum NonOdrUseReason {

    /// This is an odr-use.

    NOUR_None = 0,

    /// This name appears in an unevaluated operand.

    NOUR_Unevaluated,

    /// This name appears as a potential result of an lvalue-to-rvalue

    /// conversion that is a constant expression.

    NOUR_Constant,

    /// This name appears as a potential result of a discarded value

    /// expression.

    NOUR_Discarded,

  };

  /// Describes the kind of template specialization that a

  /// particular template specialization declaration represents.

  enum TemplateSpecializationKind {

    /// This template specialization was formed from a template-id but

    /// has not yet been declared, defined, or instantiated.

    TSK_Undeclared = 0,

    /// This template specialization was implicitly instantiated from a

    /// template. (C++ [temp.inst]).

    TSK_ImplicitInstantiation,

    /// This template specialization was declared or defined by an

    /// explicit specialization (C++ [temp.expl.spec]) or partial

    /// specialization (C++ [temp.class.spec]).

    TSK_ExplicitSpecialization,

    /// This template specialization was instantiated from a template

    /// due to an explicit instantiation declaration request

    /// (C++11 [temp.explicit]).

    TSK_ExplicitInstantiationDeclaration,

    /// This template specialization was instantiated from a template

    /// due to an explicit instantiation definition request

    /// (C++ [temp.explicit]).

    TSK_ExplicitInstantiationDefinition

  };

  /// Determine whether this template specialization kind refers

  /// to an instantiation of an entity (as opposed to a non-template or

  /// an explicit specialization).

  inline bool isTemplateInstantiation(TemplateSpecializationKind Kind) {

    return Kind != TSK_Undeclared && 
Kind != TSK_ExplicitSpecialization6.42M
;

  }

  /// True if this template specialization kind is an explicit

  /// specialization, explicit instantiation declaration, or explicit

  /// instantiation definition.

  inline bool isTemplateExplicitInstantiationOrSpecialization(

      TemplateSpecializationKind Kind) {

    switch (Kind) {

    case TSK_ExplicitSpecialization:

    case TSK_ExplicitInstantiationDeclaration:

    case TSK_ExplicitInstantiationDefinition:

      return true;

    case TSK_Undeclared:

    case TSK_ImplicitInstantiation:

      return false;

    }

    llvm_unreachable("bad template specialization kind");

  }

  /// Thread storage-class-specifier.

  enum ThreadStorageClassSpecifier {

    TSCS_unspecified,

    /// GNU __thread.

    TSCS___thread,

    /// C++11 thread_local. Implies 'static' at block scope, but not at

    /// class scope.

    TSCS_thread_local,

    /// C11 _Thread_local. Must be combined with either 'static' or 'extern'

    /// if used at block scope.

    TSCS__Thread_local

  };

  /// Storage classes.

  enum StorageClass {

    // These are legal on both functions and variables.

    SC_None,

    SC_Extern,

    SC_Static,

    SC_PrivateExtern,

    // These are only legal on variables.

    SC_Auto,

    SC_Register

  };

  /// Checks whether the given storage class is legal for functions.

  inline bool isLegalForFunction(StorageClass SC) {

    return SC <= SC_PrivateExtern;

  }

  /// Checks whether the given storage class is legal for variables.

  inline bool isLegalForVariable(StorageClass SC) {

    return true;

  }

  /// In-class initialization styles for non-static data members.

  enum InClassInitStyle {

    ICIS_NoInit,   ///< No in-class initializer.

    ICIS_CopyInit, ///< Copy initialization.

    ICIS_ListInit  ///< Direct list-initialization.

  };

  /// CallingConv - Specifies the calling convention that a function uses.

  enum CallingConv {

    CC_C,           // __attribute__((cdecl))

    CC_X86StdCall,  // __attribute__((stdcall))

    CC_X86FastCall, // __attribute__((fastcall))

    CC_X86ThisCall, // __attribute__((thiscall))

    CC_X86VectorCall, // __attribute__((vectorcall))

    CC_X86Pascal,   // __attribute__((pascal))

    CC_Win64,       // __attribute__((ms_abi))

    CC_X86_64SysV,  // __attribute__((sysv_abi))

    CC_X86RegCall, // __attribute__((regcall))

    CC_AAPCS,       // __attribute__((pcs("aapcs")))

    CC_AAPCS_VFP,   // __attribute__((pcs("aapcs-vfp")))

    CC_IntelOclBicc, // __attribute__((intel_ocl_bicc))

    CC_SpirFunction, // default for OpenCL functions on SPIR target

    CC_OpenCLKernel, // inferred for OpenCL kernels

    CC_Swift,        // __attribute__((swiftcall))

    CC_SwiftAsync,        // __attribute__((swiftasynccall))

    CC_PreserveMost, // __attribute__((preserve_most))

    CC_PreserveAll,  // __attribute__((preserve_all))

    CC_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))

    CC_AArch64SVEPCS, // __attribute__((aarch64_sve_pcs))

    CC_AMDGPUKernelCall, // __attribute__((amdgpu_kernel))

  };

  /// Checks whether the given calling convention supports variadic

  /// calls. Unprototyped calls also use the variadic call rules.

  inline bool supportsVariadicCall(CallingConv CC) {

    switch (CC) {

    case CC_X86StdCall:

    case CC_X86FastCall:

    case CC_X86ThisCall:

    case CC_X86RegCall:

    case CC_X86Pascal:

    case CC_X86VectorCall:

    case CC_SpirFunction:

    case CC_OpenCLKernel:

    case CC_Swift:

    case CC_SwiftAsync:

      return false;

    default:

      return true;

    }

  }

  /// The storage duration for an object (per C++ [basic.stc]).

  enum StorageDuration {

    SD_FullExpression, ///< Full-expression storage duration (for temporaries).

    SD_Automatic,      ///< Automatic storage duration (most local variables).

    SD_Thread,         ///< Thread storage duration.

    SD_Static,         ///< Static storage duration.

    SD_Dynamic         ///< Dynamic storage duration.

  };

  /// Describes the nullability of a particular type.

  enum class NullabilityKind : uint8_t {

    /// Values of this type can never be null.

    NonNull = 0,

    /// Values of this type can be null.

    Nullable,

    /// Whether values of this type can be null is (explicitly)

    /// unspecified. This captures a (fairly rare) case where we

    /// can't conclude anything about the nullability of the type even

    /// though it has been considered.

    Unspecified,

    // Generally behaves like Nullable, except when used in a block parameter

    // that was imported into a swift async method. There, swift will assume

    // that the parameter can get null even if no error occurred. _Nullable

    // parameters are assumed to only get null on error.

    NullableResult,

  };

  /// Return true if \p L has a weaker nullability annotation than \p R. The

  /// ordering is: Unspecified < Nullable < NonNull.

  inline bool hasWeakerNullability(NullabilityKind L, NullabilityKind R) {

    return uint8_t(L) > uint8_t(R);

  }

  /// Retrieve the spelling of the given nullability kind.

  llvm::StringRef getNullabilitySpelling(NullabilityKind kind,

                                         bool isContextSensitive = false);

  /// Kinds of parameter ABI.

  enum class ParameterABI {

    /// This parameter uses ordinary ABI rules for its type.

    Ordinary,

    /// This parameter (which must have pointer type) is a Swift

    /// indirect result parameter.

    SwiftIndirectResult,

    /// This parameter (which must have pointer-to-pointer type) uses

    /// the special Swift error-result ABI treatment.  There can be at

    /// most one parameter on a given function that uses this treatment.

    SwiftErrorResult,

    /// This parameter (which must have pointer type) uses the special

    /// Swift context-pointer ABI treatment.  There can be at

    /// most one parameter on a given function that uses this treatment.

    SwiftContext,

    /// This parameter (which must have pointer type) uses the special

    /// Swift asynchronous context-pointer ABI treatment.  There can be at

    /// most one parameter on a given function that uses this treatment.

    SwiftAsyncContext,

  };

  /// Assigned inheritance model for a class in the MS C++ ABI. Must match order

  /// of spellings in MSInheritanceAttr.

  enum class MSInheritanceModel {

    Single = 0,

    Multiple = 1,

    Virtual = 2,

    Unspecified = 3,

  };

  llvm::StringRef getParameterABISpelling(ParameterABI kind);

  inline llvm::StringRef getAccessSpelling(AccessSpecifier AS) {

    switch (AS) {

    case AccessSpecifier::AS_public:

      return "public";

    case AccessSpecifier::AS_protected:

      return "protected";

    case AccessSpecifier::AS_private:

      return "private";

    case AccessSpecifier::AS_none:

      return {};

    }

    llvm_unreachable("Unknown AccessSpecifier");

  }

} // end namespace clang

#endif // LLVM_CLANG_BASIC_SPECIFIERS_H