Specifiers.h revision 360784 
1//===--- Specifiers.h - Declaration and Type Specifiers ---------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// Defines various enumerations that describe declaration and
11/// type specifiers.
12///
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_BASIC_SPECIFIERS_H
16#define LLVM_CLANG_BASIC_SPECIFIERS_H
17
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/DataTypes.h"
20#include "llvm/Support/ErrorHandling.h"
21
22namespace clang {
23
24  /// Define the meaning of possible values of the kind in ExplicitSpecifier.
25  enum class ExplicitSpecKind : unsigned {
26    ResolvedFalse,
27    ResolvedTrue,
28    Unresolved,
29  };
30
31  /// Define the kind of constexpr specifier.
32  enum ConstexprSpecKind {
33    CSK_unspecified,
34    CSK_constexpr,
35    CSK_consteval,
36    CSK_constinit
37  };
38
39  /// Specifies the width of a type, e.g., short, long, or long long.
40  enum TypeSpecifierWidth {
41    TSW_unspecified,
42    TSW_short,
43    TSW_long,
44    TSW_longlong
45  };
46
47  /// Specifies the signedness of a type, e.g., signed or unsigned.
48  enum TypeSpecifierSign {
49    TSS_unspecified,
50    TSS_signed,
51    TSS_unsigned
52  };
53
54  enum TypeSpecifiersPipe {
55    TSP_unspecified,
56    TSP_pipe
57  };
58
59  /// Specifies the kind of type.
60  enum TypeSpecifierType {
61    TST_unspecified,
62    TST_void,
63    TST_char,
64    TST_wchar,        // C++ wchar_t
65    TST_char8,        // C++20 char8_t (proposed)
66    TST_char16,       // C++11 char16_t
67    TST_char32,       // C++11 char32_t
68    TST_int,
69    TST_int128,
70    TST_half,         // OpenCL half, ARM NEON __fp16
71    TST_Float16,      // C11 extension ISO/IEC TS 18661-3
72    TST_Accum,        // ISO/IEC JTC1 SC22 WG14 N1169 Extension
73    TST_Fract,
74    TST_float,
75    TST_double,
76    TST_float128,
77    TST_bool,         // _Bool
78    TST_decimal32,    // _Decimal32
79    TST_decimal64,    // _Decimal64
80    TST_decimal128,   // _Decimal128
81    TST_enum,
82    TST_union,
83    TST_struct,
84    TST_class,        // C++ class type
85    TST_interface,    // C++ (Microsoft-specific) __interface type
86    TST_typename,     // Typedef, C++ class-name or enum name, etc.
87    TST_typeofType,
88    TST_typeofExpr,
89    TST_decltype,         // C++11 decltype
90    TST_underlyingType,   // __underlying_type for C++11
91    TST_auto,             // C++11 auto
92    TST_decltype_auto,    // C++1y decltype(auto)
93    TST_auto_type,        // __auto_type extension
94    TST_unknown_anytype,  // __unknown_anytype extension
95    TST_atomic,           // C11 _Atomic
96#define GENERIC_IMAGE_TYPE(ImgType, Id) TST_##ImgType##_t, // OpenCL image types
97#include "clang/Basic/OpenCLImageTypes.def"
98    TST_error // erroneous type
99  };
100
101  /// Structure that packs information about the type specifiers that
102  /// were written in a particular type specifier sequence.
103  struct WrittenBuiltinSpecs {
104    static_assert(TST_error < 1 << 6, "Type bitfield not wide enough for TST");
105    /*DeclSpec::TST*/ unsigned Type  : 6;
106    /*DeclSpec::TSS*/ unsigned Sign  : 2;
107    /*DeclSpec::TSW*/ unsigned Width : 2;
108    unsigned ModeAttr : 1;
109  };
110
111  /// A C++ access specifier (public, private, protected), plus the
112  /// special value "none" which means different things in different contexts.
113  enum AccessSpecifier {
114    AS_public,
115    AS_protected,
116    AS_private,
117    AS_none
118  };
119
120  /// The categorization of expression values, currently following the
121  /// C++11 scheme.
122  enum ExprValueKind {
123    /// An r-value expression (a pr-value in the C++11 taxonomy)
124    /// produces a temporary value.
125    VK_RValue,
126
127    /// An l-value expression is a reference to an object with
128    /// independent storage.
129    VK_LValue,
130
131    /// An x-value expression is a reference to an object with
132    /// independent storage but which can be "moved", i.e.
133    /// efficiently cannibalized for its resources.
134    VK_XValue
135  };
136
137  /// A further classification of the kind of object referenced by an
138  /// l-value or x-value.
139  enum ExprObjectKind {
140    /// An ordinary object is located at an address in memory.
141    OK_Ordinary,
142
143    /// A bitfield object is a bitfield on a C or C++ record.
144    OK_BitField,
145
146    /// A vector component is an element or range of elements on a vector.
147    OK_VectorComponent,
148
149    /// An Objective-C property is a logical field of an Objective-C
150    /// object which is read and written via Objective-C method calls.
151    OK_ObjCProperty,
152
153    /// An Objective-C array/dictionary subscripting which reads an
154    /// object or writes at the subscripted array/dictionary element via
155    /// Objective-C method calls.
156    OK_ObjCSubscript
157  };
158
159  /// The reason why a DeclRefExpr does not constitute an odr-use.
160  enum NonOdrUseReason {
161    /// This is an odr-use.
162    NOUR_None = 0,
163    /// This name appears in an unevaluated operand.
164    NOUR_Unevaluated,
165    /// This name appears as a potential result of an lvalue-to-rvalue
166    /// conversion that is a constant expression.
167    NOUR_Constant,
168    /// This name appears as a potential result of a discarded value
169    /// expression.
170    NOUR_Discarded,
171  };
172
173  /// Describes the kind of template specialization that a
174  /// particular template specialization declaration represents.
175  enum TemplateSpecializationKind {
176    /// This template specialization was formed from a template-id but
177    /// has not yet been declared, defined, or instantiated.
178    TSK_Undeclared = 0,
179    /// This template specialization was implicitly instantiated from a
180    /// template. (C++ [temp.inst]).
181    TSK_ImplicitInstantiation,
182    /// This template specialization was declared or defined by an
183    /// explicit specialization (C++ [temp.expl.spec]) or partial
184    /// specialization (C++ [temp.class.spec]).
185    TSK_ExplicitSpecialization,
186    /// This template specialization was instantiated from a template
187    /// due to an explicit instantiation declaration request
188    /// (C++11 [temp.explicit]).
189    TSK_ExplicitInstantiationDeclaration,
190    /// This template specialization was instantiated from a template
191    /// due to an explicit instantiation definition request
192    /// (C++ [temp.explicit]).
193    TSK_ExplicitInstantiationDefinition
194  };
195
196  /// Determine whether this template specialization kind refers
197  /// to an instantiation of an entity (as opposed to a non-template or
198  /// an explicit specialization).
199  inline bool isTemplateInstantiation(TemplateSpecializationKind Kind) {
200    return Kind != TSK_Undeclared && Kind != TSK_ExplicitSpecialization;
201  }
202
203  /// True if this template specialization kind is an explicit
204  /// specialization, explicit instantiation declaration, or explicit
205  /// instantiation definition.
206  inline bool isTemplateExplicitInstantiationOrSpecialization(
207      TemplateSpecializationKind Kind) {
208    switch (Kind) {
209    case TSK_ExplicitSpecialization:
210    case TSK_ExplicitInstantiationDeclaration:
211    case TSK_ExplicitInstantiationDefinition:
212      return true;
213
214    case TSK_Undeclared:
215    case TSK_ImplicitInstantiation:
216      return false;
217    }
218    llvm_unreachable("bad template specialization kind");
219  }
220
221  /// Thread storage-class-specifier.
222  enum ThreadStorageClassSpecifier {
223    TSCS_unspecified,
224    /// GNU __thread.
225    TSCS___thread,
226    /// C++11 thread_local. Implies 'static' at block scope, but not at
227    /// class scope.
228    TSCS_thread_local,
229    /// C11 _Thread_local. Must be combined with either 'static' or 'extern'
230    /// if used at block scope.
231    TSCS__Thread_local
232  };
233
234  /// Storage classes.
235  enum StorageClass {
236    // These are legal on both functions and variables.
237    SC_None,
238    SC_Extern,
239    SC_Static,
240    SC_PrivateExtern,
241
242    // These are only legal on variables.
243    SC_Auto,
244    SC_Register
245  };
246
247  /// Checks whether the given storage class is legal for functions.
248  inline bool isLegalForFunction(StorageClass SC) {
249    return SC <= SC_PrivateExtern;
250  }
251
252  /// Checks whether the given storage class is legal for variables.
253  inline bool isLegalForVariable(StorageClass SC) {
254    return true;
255  }
256
257  /// In-class initialization styles for non-static data members.
258  enum InClassInitStyle {
259    ICIS_NoInit,   ///< No in-class initializer.
260    ICIS_CopyInit, ///< Copy initialization.
261    ICIS_ListInit  ///< Direct list-initialization.
262  };
263
264  /// CallingConv - Specifies the calling convention that a function uses.
265  enum CallingConv {
266    CC_C,           // __attribute__((cdecl))
267    CC_X86StdCall,  // __attribute__((stdcall))
268    CC_X86FastCall, // __attribute__((fastcall))
269    CC_X86ThisCall, // __attribute__((thiscall))
270    CC_X86VectorCall, // __attribute__((vectorcall))
271    CC_X86Pascal,   // __attribute__((pascal))
272    CC_Win64,       // __attribute__((ms_abi))
273    CC_X86_64SysV,  // __attribute__((sysv_abi))
274    CC_X86RegCall, // __attribute__((regcall))
275    CC_AAPCS,       // __attribute__((pcs("aapcs")))
276    CC_AAPCS_VFP,   // __attribute__((pcs("aapcs-vfp")))
277    CC_IntelOclBicc, // __attribute__((intel_ocl_bicc))
278    CC_SpirFunction, // default for OpenCL functions on SPIR target
279    CC_OpenCLKernel, // inferred for OpenCL kernels
280    CC_Swift,        // __attribute__((swiftcall))
281    CC_PreserveMost, // __attribute__((preserve_most))
282    CC_PreserveAll,  // __attribute__((preserve_all))
283    CC_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))
284  };
285
286  /// Checks whether the given calling convention supports variadic
287  /// calls. Unprototyped calls also use the variadic call rules.
288  inline bool supportsVariadicCall(CallingConv CC) {
289    switch (CC) {
290    case CC_X86StdCall:
291    case CC_X86FastCall:
292    case CC_X86ThisCall:
293    case CC_X86RegCall:
294    case CC_X86Pascal:
295    case CC_X86VectorCall:
296    case CC_SpirFunction:
297    case CC_OpenCLKernel:
298    case CC_Swift:
299      return false;
300    default:
301      return true;
302    }
303  }
304
305  /// The storage duration for an object (per C++ [basic.stc]).
306  enum StorageDuration {
307    SD_FullExpression, ///< Full-expression storage duration (for temporaries).
308    SD_Automatic,      ///< Automatic storage duration (most local variables).
309    SD_Thread,         ///< Thread storage duration.
310    SD_Static,         ///< Static storage duration.
311    SD_Dynamic         ///< Dynamic storage duration.
312  };
313
314  /// Describes the nullability of a particular type.
315  enum class NullabilityKind : uint8_t {
316    /// Values of this type can never be null.
317    NonNull = 0,
318    /// Values of this type can be null.
319    Nullable,
320    /// Whether values of this type can be null is (explicitly)
321    /// unspecified. This captures a (fairly rare) case where we
322    /// can't conclude anything about the nullability of the type even
323    /// though it has been considered.
324    Unspecified
325  };
326
327  /// Return true if \p L has a weaker nullability annotation than \p R. The
328  /// ordering is: Unspecified < Nullable < NonNull.
329  inline bool hasWeakerNullability(NullabilityKind L, NullabilityKind R) {
330    return uint8_t(L) > uint8_t(R);
331  }
332
333  /// Retrieve the spelling of the given nullability kind.
334  llvm::StringRef getNullabilitySpelling(NullabilityKind kind,
335                                         bool isContextSensitive = false);
336
337  /// Kinds of parameter ABI.
338  enum class ParameterABI {
339    /// This parameter uses ordinary ABI rules for its type.
340    Ordinary,
341
342    /// This parameter (which must have pointer type) is a Swift
343    /// indirect result parameter.
344    SwiftIndirectResult,
345
346    /// This parameter (which must have pointer-to-pointer type) uses
347    /// the special Swift error-result ABI treatment.  There can be at
348    /// most one parameter on a given function that uses this treatment.
349    SwiftErrorResult,
350
351    /// This parameter (which must have pointer type) uses the special
352    /// Swift context-pointer ABI treatment.  There can be at
353    /// most one parameter on a given function that uses this treatment.
354    SwiftContext
355  };
356
357  /// Assigned inheritance model for a class in the MS C++ ABI. Must match order
358  /// of spellings in MSInheritanceAttr.
359  enum class MSInheritanceModel {
360    Single = 0,
361    Multiple = 1,
362    Virtual = 2,
363    Unspecified = 3,
364  };
365
366  llvm::StringRef getParameterABISpelling(ParameterABI kind);
367} // end namespace clang
368
369#endif // LLVM_CLANG_BASIC_SPECIFIERS_H
370