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