xref: /freebsd/contrib/llvm-project/clang/include/clang/Basic/Specifiers.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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     TST_error // erroneous type
102   };
103 
104   /// Structure that packs information about the type specifiers that
105   /// were written in a particular type specifier sequence.
106   struct WrittenBuiltinSpecs {
107     static_assert(TST_error < 1 << 7, "Type bitfield not wide enough for TST");
108     LLVM_PREFERRED_TYPE(TypeSpecifierType)
109     unsigned Type : 7;
110     LLVM_PREFERRED_TYPE(TypeSpecifierSign)
111     unsigned Sign : 2;
112     LLVM_PREFERRED_TYPE(TypeSpecifierWidth)
113     unsigned Width : 2;
114     LLVM_PREFERRED_TYPE(bool)
115     unsigned ModeAttr : 1;
116   };
117 
118   /// A C++ access specifier (public, private, protected), plus the
119   /// special value "none" which means different things in different contexts.
120   enum AccessSpecifier {
121     AS_public,
122     AS_protected,
123     AS_private,
124     AS_none
125   };
126 
127   /// The categorization of expression values, currently following the
128   /// C++11 scheme.
129   enum ExprValueKind {
130     /// A pr-value expression (in the C++11 taxonomy)
131     /// produces a temporary value.
132     VK_PRValue,
133 
134     /// An l-value expression is a reference to an object with
135     /// independent storage.
136     VK_LValue,
137 
138     /// An x-value expression is a reference to an object with
139     /// independent storage but which can be "moved", i.e.
140     /// efficiently cannibalized for its resources.
141     VK_XValue
142   };
143 
144   /// A further classification of the kind of object referenced by an
145   /// l-value or x-value.
146   enum ExprObjectKind {
147     /// An ordinary object is located at an address in memory.
148     OK_Ordinary,
149 
150     /// A bitfield object is a bitfield on a C or C++ record.
151     OK_BitField,
152 
153     /// A vector component is an element or range of elements on a vector.
154     OK_VectorComponent,
155 
156     /// An Objective-C property is a logical field of an Objective-C
157     /// object which is read and written via Objective-C method calls.
158     OK_ObjCProperty,
159 
160     /// An Objective-C array/dictionary subscripting which reads an
161     /// object or writes at the subscripted array/dictionary element via
162     /// Objective-C method calls.
163     OK_ObjCSubscript,
164 
165     /// A matrix component is a single element of a matrix.
166     OK_MatrixComponent
167   };
168 
169   /// The reason why a DeclRefExpr does not constitute an odr-use.
170   enum NonOdrUseReason {
171     /// This is an odr-use.
172     NOUR_None = 0,
173     /// This name appears in an unevaluated operand.
174     NOUR_Unevaluated,
175     /// This name appears as a potential result of an lvalue-to-rvalue
176     /// conversion that is a constant expression.
177     NOUR_Constant,
178     /// This name appears as a potential result of a discarded value
179     /// expression.
180     NOUR_Discarded,
181   };
182 
183   /// Describes the kind of template specialization that a
184   /// particular template specialization declaration represents.
185   enum TemplateSpecializationKind {
186     /// This template specialization was formed from a template-id but
187     /// has not yet been declared, defined, or instantiated.
188     TSK_Undeclared = 0,
189     /// This template specialization was implicitly instantiated from a
190     /// template. (C++ [temp.inst]).
191     TSK_ImplicitInstantiation,
192     /// This template specialization was declared or defined by an
193     /// explicit specialization (C++ [temp.expl.spec]) or partial
194     /// specialization (C++ [temp.class.spec]).
195     TSK_ExplicitSpecialization,
196     /// This template specialization was instantiated from a template
197     /// due to an explicit instantiation declaration request
198     /// (C++11 [temp.explicit]).
199     TSK_ExplicitInstantiationDeclaration,
200     /// This template specialization was instantiated from a template
201     /// due to an explicit instantiation definition request
202     /// (C++ [temp.explicit]).
203     TSK_ExplicitInstantiationDefinition
204   };
205 
206   /// Determine whether this template specialization kind refers
207   /// to an instantiation of an entity (as opposed to a non-template or
208   /// an explicit specialization).
isTemplateInstantiation(TemplateSpecializationKind Kind)209   inline bool isTemplateInstantiation(TemplateSpecializationKind Kind) {
210     return Kind != TSK_Undeclared && Kind != TSK_ExplicitSpecialization;
211   }
212 
213   /// True if this template specialization kind is an explicit
214   /// specialization, explicit instantiation declaration, or explicit
215   /// instantiation definition.
isTemplateExplicitInstantiationOrSpecialization(TemplateSpecializationKind Kind)216   inline bool isTemplateExplicitInstantiationOrSpecialization(
217       TemplateSpecializationKind Kind) {
218     switch (Kind) {
219     case TSK_ExplicitSpecialization:
220     case TSK_ExplicitInstantiationDeclaration:
221     case TSK_ExplicitInstantiationDefinition:
222       return true;
223 
224     case TSK_Undeclared:
225     case TSK_ImplicitInstantiation:
226       return false;
227     }
228     llvm_unreachable("bad template specialization kind");
229   }
230 
231   /// Thread storage-class-specifier.
232   enum ThreadStorageClassSpecifier {
233     TSCS_unspecified,
234     /// GNU __thread.
235     TSCS___thread,
236     /// C++11 thread_local. Implies 'static' at block scope, but not at
237     /// class scope.
238     TSCS_thread_local,
239     /// C11 _Thread_local. Must be combined with either 'static' or 'extern'
240     /// if used at block scope.
241     TSCS__Thread_local
242   };
243 
244   /// Storage classes.
245   enum StorageClass {
246     // These are legal on both functions and variables.
247     SC_None,
248     SC_Extern,
249     SC_Static,
250     SC_PrivateExtern,
251 
252     // These are only legal on variables.
253     SC_Auto,
254     SC_Register
255   };
256 
257   /// Checks whether the given storage class is legal for functions.
isLegalForFunction(StorageClass SC)258   inline bool isLegalForFunction(StorageClass SC) {
259     return SC <= SC_PrivateExtern;
260   }
261 
262   /// Checks whether the given storage class is legal for variables.
isLegalForVariable(StorageClass SC)263   inline bool isLegalForVariable(StorageClass SC) {
264     return true;
265   }
266 
267   /// In-class initialization styles for non-static data members.
268   enum InClassInitStyle {
269     ICIS_NoInit,   ///< No in-class initializer.
270     ICIS_CopyInit, ///< Copy initialization.
271     ICIS_ListInit  ///< Direct list-initialization.
272   };
273 
274   /// CallingConv - Specifies the calling convention that a function uses.
275   enum CallingConv {
276     CC_C,                 // __attribute__((cdecl))
277     CC_X86StdCall,        // __attribute__((stdcall))
278     CC_X86FastCall,       // __attribute__((fastcall))
279     CC_X86ThisCall,       // __attribute__((thiscall))
280     CC_X86VectorCall,     // __attribute__((vectorcall))
281     CC_X86Pascal,         // __attribute__((pascal))
282     CC_Win64,             // __attribute__((ms_abi))
283     CC_X86_64SysV,        // __attribute__((sysv_abi))
284     CC_X86RegCall,        // __attribute__((regcall))
285     CC_AAPCS,             // __attribute__((pcs("aapcs")))
286     CC_AAPCS_VFP,         // __attribute__((pcs("aapcs-vfp")))
287     CC_IntelOclBicc,      // __attribute__((intel_ocl_bicc))
288     CC_SpirFunction,      // default for OpenCL functions on SPIR target
289     CC_OpenCLKernel,      // inferred for OpenCL kernels
290     CC_Swift,             // __attribute__((swiftcall))
291     CC_SwiftAsync,        // __attribute__((swiftasynccall))
292     CC_PreserveMost,      // __attribute__((preserve_most))
293     CC_PreserveAll,       // __attribute__((preserve_all))
294     CC_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))
295     CC_AArch64SVEPCS,     // __attribute__((aarch64_sve_pcs))
296     CC_AMDGPUKernelCall,  // __attribute__((amdgpu_kernel))
297     CC_M68kRTD,           // __attribute__((m68k_rtd))
298     CC_PreserveNone,      // __attribute__((preserve_none))
299     CC_RISCVVectorCall,   // __attribute__((riscv_vector_cc))
300   };
301 
302   /// Checks whether the given calling convention supports variadic
303   /// calls. Unprototyped calls also use the variadic call rules.
supportsVariadicCall(CallingConv CC)304   inline bool supportsVariadicCall(CallingConv CC) {
305     switch (CC) {
306     case CC_X86StdCall:
307     case CC_X86FastCall:
308     case CC_X86ThisCall:
309     case CC_X86RegCall:
310     case CC_X86Pascal:
311     case CC_X86VectorCall:
312     case CC_SpirFunction:
313     case CC_OpenCLKernel:
314     case CC_Swift:
315     case CC_SwiftAsync:
316     case CC_M68kRTD:
317       return false;
318     default:
319       return true;
320     }
321   }
322 
323   /// The storage duration for an object (per C++ [basic.stc]).
324   enum StorageDuration {
325     SD_FullExpression, ///< Full-expression storage duration (for temporaries).
326     SD_Automatic,      ///< Automatic storage duration (most local variables).
327     SD_Thread,         ///< Thread storage duration.
328     SD_Static,         ///< Static storage duration.
329     SD_Dynamic         ///< Dynamic storage duration.
330   };
331 
332   /// Describes the nullability of a particular type.
333   enum class NullabilityKind : uint8_t {
334     /// Values of this type can never be null.
335     NonNull = 0,
336     /// Values of this type can be null.
337     Nullable,
338     /// Whether values of this type can be null is (explicitly)
339     /// unspecified. This captures a (fairly rare) case where we
340     /// can't conclude anything about the nullability of the type even
341     /// though it has been considered.
342     Unspecified,
343     // Generally behaves like Nullable, except when used in a block parameter
344     // that was imported into a swift async method. There, swift will assume
345     // that the parameter can get null even if no error occurred. _Nullable
346     // parameters are assumed to only get null on error.
347     NullableResult,
348   };
349   /// Prints human-readable debug representation.
350   llvm::raw_ostream &operator<<(llvm::raw_ostream&, NullabilityKind);
351 
352   /// Return true if \p L has a weaker nullability annotation than \p R. The
353   /// ordering is: Unspecified < Nullable < NonNull.
hasWeakerNullability(NullabilityKind L,NullabilityKind R)354   inline bool hasWeakerNullability(NullabilityKind L, NullabilityKind R) {
355     return uint8_t(L) > uint8_t(R);
356   }
357 
358   /// Retrieve the spelling of the given nullability kind.
359   llvm::StringRef getNullabilitySpelling(NullabilityKind kind,
360                                          bool isContextSensitive = false);
361 
362   /// Kinds of parameter ABI.
363   enum class ParameterABI {
364     /// This parameter uses ordinary ABI rules for its type.
365     Ordinary,
366 
367     /// This parameter (which must have pointer type) is a Swift
368     /// indirect result parameter.
369     SwiftIndirectResult,
370 
371     /// This parameter (which must have pointer-to-pointer type) uses
372     /// the special Swift error-result ABI treatment.  There can be at
373     /// most one parameter on a given function that uses this treatment.
374     SwiftErrorResult,
375 
376     /// This parameter (which must have pointer type) uses the special
377     /// Swift context-pointer ABI treatment.  There can be at
378     /// most one parameter on a given function that uses this treatment.
379     SwiftContext,
380 
381     /// This parameter (which must have pointer type) uses the special
382     /// Swift asynchronous context-pointer ABI treatment.  There can be at
383     /// most one parameter on a given function that uses this treatment.
384     SwiftAsyncContext,
385   };
386 
387   /// Assigned inheritance model for a class in the MS C++ ABI. Must match order
388   /// of spellings in MSInheritanceAttr.
389   enum class MSInheritanceModel {
390     Single = 0,
391     Multiple = 1,
392     Virtual = 2,
393     Unspecified = 3,
394   };
395 
396   llvm::StringRef getParameterABISpelling(ParameterABI kind);
397 
getAccessSpelling(AccessSpecifier AS)398   inline llvm::StringRef getAccessSpelling(AccessSpecifier AS) {
399     switch (AS) {
400     case AccessSpecifier::AS_public:
401       return "public";
402     case AccessSpecifier::AS_protected:
403       return "protected";
404     case AccessSpecifier::AS_private:
405       return "private";
406     case AccessSpecifier::AS_none:
407       return {};
408     }
409     llvm_unreachable("Unknown AccessSpecifier");
410   }
411 } // end namespace clang
412 
413 #endif // LLVM_CLANG_BASIC_SPECIFIERS_H
414