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 
22 namespace 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