xref: /llvm-project/clang/include/clang/Basic/Specifiers.h (revision 89fb8490a99e612f7a574e8678b21a90f689f5b4)
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 llvm {
23 class raw_ostream;
24 } // namespace llvm
25 namespace clang {
26 
27   /// Define the meaning of possible values of the kind in ExplicitSpecifier.
28   enum class ExplicitSpecKind : unsigned {
29     ResolvedFalse,
30     ResolvedTrue,
31     Unresolved,
32   };
33 
34   /// Define the kind of constexpr specifier.
35   enum class ConstexprSpecKind { Unspecified, Constexpr, Consteval, Constinit };
36 
37   /// In an if statement, this denotes whether the statement is
38   /// a constexpr or consteval if statement.
39   enum class IfStatementKind : unsigned {
40     Ordinary,
41     Constexpr,
42     ConstevalNonNegated,
43     ConstevalNegated
44   };
45 
46   /// Specifies the width of a type, e.g., short, long, or long long.
47   enum class TypeSpecifierWidth { Unspecified, Short, Long, LongLong };
48 
49   /// Specifies the signedness of a type, e.g., signed or unsigned.
50   enum class TypeSpecifierSign { Unspecified, Signed, Unsigned };
51 
52   enum class TypeSpecifiersPipe { Unspecified, Pipe };
53 
54   /// Specifies the kind of type.
55   enum TypeSpecifierType {
56     TST_unspecified,
57     TST_void,
58     TST_char,
59     TST_wchar,  // C++ wchar_t
60     TST_char8,  // C++20 char8_t (proposed)
61     TST_char16, // C++11 char16_t
62     TST_char32, // C++11 char32_t
63     TST_int,
64     TST_int128,
65     TST_bitint,  // Bit-precise integer types.
66     TST_half,    // OpenCL half, ARM NEON __fp16
67     TST_Float16, // C11 extension ISO/IEC TS 18661-3
68     TST_Accum,   // ISO/IEC JTC1 SC22 WG14 N1169 Extension
69     TST_Fract,
70     TST_BFloat16,
71     TST_float,
72     TST_double,
73     TST_float128,
74     TST_ibm128,
75     TST_bool,       // _Bool
76     TST_decimal32,  // _Decimal32
77     TST_decimal64,  // _Decimal64
78     TST_decimal128, // _Decimal128
79     TST_enum,
80     TST_union,
81     TST_struct,
82     TST_class,             // C++ class type
83     TST_interface,         // C++ (Microsoft-specific) __interface type
84     TST_typename,          // Typedef, C++ class-name or enum name, etc.
85     TST_typeofType,        // C23 (and GNU extension) typeof(type-name)
86     TST_typeofExpr,        // C23 (and GNU extension) typeof(expression)
87     TST_typeof_unqualType, // C23 typeof_unqual(type-name)
88     TST_typeof_unqualExpr, // C23 typeof_unqual(expression)
89     TST_decltype,          // C++11 decltype
90 #define TRANSFORM_TYPE_TRAIT_DEF(_, Trait) TST_##Trait,
91 #include "clang/Basic/TransformTypeTraits.def"
92     TST_auto,            // C++11 auto
93     TST_decltype_auto,   // C++1y decltype(auto)
94     TST_auto_type,       // __auto_type extension
95     TST_unknown_anytype, // __unknown_anytype extension
96     TST_atomic,          // C11 _Atomic
97     TST_typename_pack_indexing,
98 #define GENERIC_IMAGE_TYPE(ImgType, Id)                                      \
99     TST_##ImgType##_t, // OpenCL image types
100 #include "clang/Basic/OpenCLImageTypes.def"
101 #define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId)                          \
102     TST_##Name, // HLSL Intangible Types
103 #include "clang/Basic/HLSLIntangibleTypes.def"
104     TST_error // erroneous type
105   };
106 
107   /// Structure that packs information about the type specifiers that
108   /// were written in a particular type specifier sequence.
109   struct WrittenBuiltinSpecs {
110     static_assert(TST_error < 1 << 7, "Type bitfield not wide enough for TST");
111     LLVM_PREFERRED_TYPE(TypeSpecifierType)
112     unsigned Type : 7;
113     LLVM_PREFERRED_TYPE(TypeSpecifierSign)
114     unsigned Sign : 2;
115     LLVM_PREFERRED_TYPE(TypeSpecifierWidth)
116     unsigned Width : 2;
117     LLVM_PREFERRED_TYPE(bool)
118     unsigned ModeAttr : 1;
119   };
120 
121   /// A C++ access specifier (public, private, protected), plus the
122   /// special value "none" which means different things in different contexts.
123   enum AccessSpecifier {
124     AS_public,
125     AS_protected,
126     AS_private,
127     AS_none
128   };
129 
130   /// The categorization of expression values, currently following the
131   /// C++11 scheme.
132   enum ExprValueKind {
133     /// A pr-value expression (in the C++11 taxonomy)
134     /// produces a temporary value.
135     VK_PRValue,
136 
137     /// An l-value expression is a reference to an object with
138     /// independent storage.
139     VK_LValue,
140 
141     /// An x-value expression is a reference to an object with
142     /// independent storage but which can be "moved", i.e.
143     /// efficiently cannibalized for its resources.
144     VK_XValue
145   };
146 
147   /// A further classification of the kind of object referenced by an
148   /// l-value or x-value.
149   enum ExprObjectKind {
150     /// An ordinary object is located at an address in memory.
151     OK_Ordinary,
152 
153     /// A bitfield object is a bitfield on a C or C++ record.
154     OK_BitField,
155 
156     /// A vector component is an element or range of elements on a vector.
157     OK_VectorComponent,
158 
159     /// An Objective-C property is a logical field of an Objective-C
160     /// object which is read and written via Objective-C method calls.
161     OK_ObjCProperty,
162 
163     /// An Objective-C array/dictionary subscripting which reads an
164     /// object or writes at the subscripted array/dictionary element via
165     /// Objective-C method calls.
166     OK_ObjCSubscript,
167 
168     /// A matrix component is a single element of a matrix.
169     OK_MatrixComponent
170   };
171 
172   /// The reason why a DeclRefExpr does not constitute an odr-use.
173   enum NonOdrUseReason {
174     /// This is an odr-use.
175     NOUR_None = 0,
176     /// This name appears in an unevaluated operand.
177     NOUR_Unevaluated,
178     /// This name appears as a potential result of an lvalue-to-rvalue
179     /// conversion that is a constant expression.
180     NOUR_Constant,
181     /// This name appears as a potential result of a discarded value
182     /// expression.
183     NOUR_Discarded,
184   };
185 
186   /// Describes the kind of template specialization that a
187   /// particular template specialization declaration represents.
188   enum TemplateSpecializationKind {
189     /// This template specialization was formed from a template-id but
190     /// has not yet been declared, defined, or instantiated.
191     TSK_Undeclared = 0,
192     /// This template specialization was implicitly instantiated from a
193     /// template. (C++ [temp.inst]).
194     TSK_ImplicitInstantiation,
195     /// This template specialization was declared or defined by an
196     /// explicit specialization (C++ [temp.expl.spec]) or partial
197     /// specialization (C++ [temp.class.spec]).
198     TSK_ExplicitSpecialization,
199     /// This template specialization was instantiated from a template
200     /// due to an explicit instantiation declaration request
201     /// (C++11 [temp.explicit]).
202     TSK_ExplicitInstantiationDeclaration,
203     /// This template specialization was instantiated from a template
204     /// due to an explicit instantiation definition request
205     /// (C++ [temp.explicit]).
206     TSK_ExplicitInstantiationDefinition
207   };
208 
209   /// Determine whether this template specialization kind refers
210   /// to an instantiation of an entity (as opposed to a non-template or
211   /// an explicit specialization).
212   inline bool isTemplateInstantiation(TemplateSpecializationKind Kind) {
213     return Kind != TSK_Undeclared && Kind != TSK_ExplicitSpecialization;
214   }
215 
216   /// True if this template specialization kind is an explicit
217   /// specialization, explicit instantiation declaration, or explicit
218   /// instantiation definition.
219   inline bool isTemplateExplicitInstantiationOrSpecialization(
220       TemplateSpecializationKind Kind) {
221     switch (Kind) {
222     case TSK_ExplicitSpecialization:
223     case TSK_ExplicitInstantiationDeclaration:
224     case TSK_ExplicitInstantiationDefinition:
225       return true;
226 
227     case TSK_Undeclared:
228     case TSK_ImplicitInstantiation:
229       return false;
230     }
231     llvm_unreachable("bad template specialization kind");
232   }
233 
234   /// Thread storage-class-specifier.
235   enum ThreadStorageClassSpecifier {
236     TSCS_unspecified,
237     /// GNU __thread.
238     TSCS___thread,
239     /// C++11 thread_local. Implies 'static' at block scope, but not at
240     /// class scope.
241     TSCS_thread_local,
242     /// C11 _Thread_local. Must be combined with either 'static' or 'extern'
243     /// if used at block scope.
244     TSCS__Thread_local
245   };
246 
247   /// Storage classes.
248   enum StorageClass {
249     // These are legal on both functions and variables.
250     SC_None,
251     SC_Extern,
252     SC_Static,
253     SC_PrivateExtern,
254 
255     // These are only legal on variables.
256     SC_Auto,
257     SC_Register
258   };
259 
260   /// Checks whether the given storage class is legal for functions.
261   inline bool isLegalForFunction(StorageClass SC) {
262     return SC <= SC_PrivateExtern;
263   }
264 
265   /// Checks whether the given storage class is legal for variables.
266   inline bool isLegalForVariable(StorageClass SC) {
267     return true;
268   }
269 
270   /// In-class initialization styles for non-static data members.
271   enum InClassInitStyle {
272     ICIS_NoInit,   ///< No in-class initializer.
273     ICIS_CopyInit, ///< Copy initialization.
274     ICIS_ListInit  ///< Direct list-initialization.
275   };
276 
277   /// CallingConv - Specifies the calling convention that a function uses.
278   enum CallingConv {
279     CC_C,                 // __attribute__((cdecl))
280     CC_X86StdCall,        // __attribute__((stdcall))
281     CC_X86FastCall,       // __attribute__((fastcall))
282     CC_X86ThisCall,       // __attribute__((thiscall))
283     CC_X86VectorCall,     // __attribute__((vectorcall))
284     CC_X86Pascal,         // __attribute__((pascal))
285     CC_Win64,             // __attribute__((ms_abi))
286     CC_X86_64SysV,        // __attribute__((sysv_abi))
287     CC_X86RegCall,        // __attribute__((regcall))
288     CC_AAPCS,             // __attribute__((pcs("aapcs")))
289     CC_AAPCS_VFP,         // __attribute__((pcs("aapcs-vfp")))
290     CC_IntelOclBicc,      // __attribute__((intel_ocl_bicc))
291     CC_SpirFunction,      // default for OpenCL functions on SPIR target
292     CC_OpenCLKernel,      // inferred for OpenCL kernels
293     CC_Swift,             // __attribute__((swiftcall))
294     CC_SwiftAsync,        // __attribute__((swiftasynccall))
295     CC_PreserveMost,      // __attribute__((preserve_most))
296     CC_PreserveAll,       // __attribute__((preserve_all))
297     CC_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))
298     CC_AArch64SVEPCS,     // __attribute__((aarch64_sve_pcs))
299     CC_AMDGPUKernelCall,  // __attribute__((amdgpu_kernel))
300     CC_M68kRTD,           // __attribute__((m68k_rtd))
301     CC_PreserveNone,      // __attribute__((preserve_none))
302     CC_RISCVVectorCall,   // __attribute__((riscv_vector_cc))
303   };
304 
305   /// Checks whether the given calling convention supports variadic
306   /// calls. Unprototyped calls also use the variadic call rules.
307   inline bool supportsVariadicCall(CallingConv CC) {
308     switch (CC) {
309     case CC_X86StdCall:
310     case CC_X86FastCall:
311     case CC_X86ThisCall:
312     case CC_X86RegCall:
313     case CC_X86Pascal:
314     case CC_X86VectorCall:
315     case CC_SpirFunction:
316     case CC_OpenCLKernel:
317     case CC_Swift:
318     case CC_SwiftAsync:
319     case CC_M68kRTD:
320       return false;
321     default:
322       return true;
323     }
324   }
325 
326   /// The storage duration for an object (per C++ [basic.stc]).
327   enum StorageDuration {
328     SD_FullExpression, ///< Full-expression storage duration (for temporaries).
329     SD_Automatic,      ///< Automatic storage duration (most local variables).
330     SD_Thread,         ///< Thread storage duration.
331     SD_Static,         ///< Static storage duration.
332     SD_Dynamic         ///< Dynamic storage duration.
333   };
334 
335   /// Describes the nullability of a particular type.
336   enum class NullabilityKind : uint8_t {
337     /// Values of this type can never be null.
338     NonNull = 0,
339     /// Values of this type can be null.
340     Nullable,
341     /// Whether values of this type can be null is (explicitly)
342     /// unspecified. This captures a (fairly rare) case where we
343     /// can't conclude anything about the nullability of the type even
344     /// though it has been considered.
345     Unspecified,
346     // Generally behaves like Nullable, except when used in a block parameter
347     // that was imported into a swift async method. There, swift will assume
348     // that the parameter can get null even if no error occurred. _Nullable
349     // parameters are assumed to only get null on error.
350     NullableResult,
351   };
352   /// Prints human-readable debug representation.
353   llvm::raw_ostream &operator<<(llvm::raw_ostream&, NullabilityKind);
354 
355   /// Return true if \p L has a weaker nullability annotation than \p R. The
356   /// ordering is: Unspecified < Nullable < NonNull.
357   inline bool hasWeakerNullability(NullabilityKind L, NullabilityKind R) {
358     return uint8_t(L) > uint8_t(R);
359   }
360 
361   /// Retrieve the spelling of the given nullability kind.
362   llvm::StringRef getNullabilitySpelling(NullabilityKind kind,
363                                          bool isContextSensitive = false);
364 
365   /// Kinds of parameter ABI.
366   enum class ParameterABI {
367     /// This parameter uses ordinary ABI rules for its type.
368     Ordinary,
369 
370     /// This parameter (which must have pointer type) is a Swift
371     /// indirect result parameter.
372     SwiftIndirectResult,
373 
374     /// This parameter (which must have pointer-to-pointer type) uses
375     /// the special Swift error-result ABI treatment.  There can be at
376     /// most one parameter on a given function that uses this treatment.
377     SwiftErrorResult,
378 
379     /// This parameter (which must have pointer type) uses the special
380     /// Swift context-pointer ABI treatment.  There can be at
381     /// most one parameter on a given function that uses this treatment.
382     SwiftContext,
383 
384     /// This parameter (which must have pointer type) uses the special
385     /// Swift asynchronous context-pointer ABI treatment.  There can be at
386     /// most one parameter on a given function that uses this treatment.
387     SwiftAsyncContext,
388 
389     // This parameter is a copy-out HLSL parameter.
390     HLSLOut,
391 
392     // This parameter is a copy-in/copy-out HLSL parameter.
393     HLSLInOut,
394   };
395 
396   /// Assigned inheritance model for a class in the MS C++ ABI. Must match order
397   /// of spellings in MSInheritanceAttr.
398   enum class MSInheritanceModel {
399     Single = 0,
400     Multiple = 1,
401     Virtual = 2,
402     Unspecified = 3,
403   };
404 
405   llvm::StringRef getParameterABISpelling(ParameterABI kind);
406 
407   inline llvm::StringRef getAccessSpelling(AccessSpecifier AS) {
408     switch (AS) {
409     case AccessSpecifier::AS_public:
410       return "public";
411     case AccessSpecifier::AS_protected:
412       return "protected";
413     case AccessSpecifier::AS_private:
414       return "private";
415     case AccessSpecifier::AS_none:
416       return {};
417     }
418     llvm_unreachable("Unknown AccessSpecifier");
419   }
420 } // end namespace clang
421 
422 #endif // LLVM_CLANG_BASIC_SPECIFIERS_H
423