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 #define GENERIC_IMAGE_TYPE(ImgType, Id) TST_##ImgType##_t, // OpenCL image types
98 #include "clang/Basic/OpenCLImageTypes.def"
99     TST_error // erroneous type
100   };
101 
102   /// Structure that packs information about the type specifiers that
103   /// were written in a particular type specifier sequence.
104   struct WrittenBuiltinSpecs {
105     static_assert(TST_error < 1 << 7, "Type bitfield not wide enough for TST");
106     LLVM_PREFERRED_TYPE(TypeSpecifierType)
107     unsigned Type : 7;
108     LLVM_PREFERRED_TYPE(TypeSpecifierSign)
109     unsigned Sign : 2;
110     LLVM_PREFERRED_TYPE(TypeSpecifierWidth)
111     unsigned Width : 2;
112     LLVM_PREFERRED_TYPE(bool)
113     unsigned ModeAttr : 1;
114   };
115 
116   /// A C++ access specifier (public, private, protected), plus the
117   /// special value "none" which means different things in different contexts.
118   enum AccessSpecifier {
119     AS_public,
120     AS_protected,
121     AS_private,
122     AS_none
123   };
124 
125   /// The categorization of expression values, currently following the
126   /// C++11 scheme.
127   enum ExprValueKind {
128     /// A pr-value expression (in the C++11 taxonomy)
129     /// produces a temporary value.
130     VK_PRValue,
131 
132     /// An l-value expression is a reference to an object with
133     /// independent storage.
134     VK_LValue,
135 
136     /// An x-value expression is a reference to an object with
137     /// independent storage but which can be "moved", i.e.
138     /// efficiently cannibalized for its resources.
139     VK_XValue
140   };
141 
142   /// A further classification of the kind of object referenced by an
143   /// l-value or x-value.
144   enum ExprObjectKind {
145     /// An ordinary object is located at an address in memory.
146     OK_Ordinary,
147 
148     /// A bitfield object is a bitfield on a C or C++ record.
149     OK_BitField,
150 
151     /// A vector component is an element or range of elements on a vector.
152     OK_VectorComponent,
153 
154     /// An Objective-C property is a logical field of an Objective-C
155     /// object which is read and written via Objective-C method calls.
156     OK_ObjCProperty,
157 
158     /// An Objective-C array/dictionary subscripting which reads an
159     /// object or writes at the subscripted array/dictionary element via
160     /// Objective-C method calls.
161     OK_ObjCSubscript,
162 
163     /// A matrix component is a single element of a matrix.
164     OK_MatrixComponent
165   };
166 
167   /// The reason why a DeclRefExpr does not constitute an odr-use.
168   enum NonOdrUseReason {
169     /// This is an odr-use.
170     NOUR_None = 0,
171     /// This name appears in an unevaluated operand.
172     NOUR_Unevaluated,
173     /// This name appears as a potential result of an lvalue-to-rvalue
174     /// conversion that is a constant expression.
175     NOUR_Constant,
176     /// This name appears as a potential result of a discarded value
177     /// expression.
178     NOUR_Discarded,
179   };
180 
181   /// Describes the kind of template specialization that a
182   /// particular template specialization declaration represents.
183   enum TemplateSpecializationKind {
184     /// This template specialization was formed from a template-id but
185     /// has not yet been declared, defined, or instantiated.
186     TSK_Undeclared = 0,
187     /// This template specialization was implicitly instantiated from a
188     /// template. (C++ [temp.inst]).
189     TSK_ImplicitInstantiation,
190     /// This template specialization was declared or defined by an
191     /// explicit specialization (C++ [temp.expl.spec]) or partial
192     /// specialization (C++ [temp.class.spec]).
193     TSK_ExplicitSpecialization,
194     /// This template specialization was instantiated from a template
195     /// due to an explicit instantiation declaration request
196     /// (C++11 [temp.explicit]).
197     TSK_ExplicitInstantiationDeclaration,
198     /// This template specialization was instantiated from a template
199     /// due to an explicit instantiation definition request
200     /// (C++ [temp.explicit]).
201     TSK_ExplicitInstantiationDefinition
202   };
203 
204   /// Determine whether this template specialization kind refers
205   /// to an instantiation of an entity (as opposed to a non-template or
206   /// an explicit specialization).
isTemplateInstantiation(TemplateSpecializationKind Kind)207   inline bool isTemplateInstantiation(TemplateSpecializationKind Kind) {
208     return Kind != TSK_Undeclared && Kind != TSK_ExplicitSpecialization;
209   }
210 
211   /// True if this template specialization kind is an explicit
212   /// specialization, explicit instantiation declaration, or explicit
213   /// instantiation definition.
isTemplateExplicitInstantiationOrSpecialization(TemplateSpecializationKind Kind)214   inline bool isTemplateExplicitInstantiationOrSpecialization(
215       TemplateSpecializationKind Kind) {
216     switch (Kind) {
217     case TSK_ExplicitSpecialization:
218     case TSK_ExplicitInstantiationDeclaration:
219     case TSK_ExplicitInstantiationDefinition:
220       return true;
221 
222     case TSK_Undeclared:
223     case TSK_ImplicitInstantiation:
224       return false;
225     }
226     llvm_unreachable("bad template specialization kind");
227   }
228 
229   /// Thread storage-class-specifier.
230   enum ThreadStorageClassSpecifier {
231     TSCS_unspecified,
232     /// GNU __thread.
233     TSCS___thread,
234     /// C++11 thread_local. Implies 'static' at block scope, but not at
235     /// class scope.
236     TSCS_thread_local,
237     /// C11 _Thread_local. Must be combined with either 'static' or 'extern'
238     /// if used at block scope.
239     TSCS__Thread_local
240   };
241 
242   /// Storage classes.
243   enum StorageClass {
244     // These are legal on both functions and variables.
245     SC_None,
246     SC_Extern,
247     SC_Static,
248     SC_PrivateExtern,
249 
250     // These are only legal on variables.
251     SC_Auto,
252     SC_Register
253   };
254 
255   /// Checks whether the given storage class is legal for functions.
isLegalForFunction(StorageClass SC)256   inline bool isLegalForFunction(StorageClass SC) {
257     return SC <= SC_PrivateExtern;
258   }
259 
260   /// Checks whether the given storage class is legal for variables.
isLegalForVariable(StorageClass SC)261   inline bool isLegalForVariable(StorageClass SC) {
262     return true;
263   }
264 
265   /// In-class initialization styles for non-static data members.
266   enum InClassInitStyle {
267     ICIS_NoInit,   ///< No in-class initializer.
268     ICIS_CopyInit, ///< Copy initialization.
269     ICIS_ListInit  ///< Direct list-initialization.
270   };
271 
272   /// CallingConv - Specifies the calling convention that a function uses.
273   enum CallingConv {
274     CC_C,           // __attribute__((cdecl))
275     CC_X86StdCall,  // __attribute__((stdcall))
276     CC_X86FastCall, // __attribute__((fastcall))
277     CC_X86ThisCall, // __attribute__((thiscall))
278     CC_X86VectorCall, // __attribute__((vectorcall))
279     CC_X86Pascal,   // __attribute__((pascal))
280     CC_Win64,       // __attribute__((ms_abi))
281     CC_X86_64SysV,  // __attribute__((sysv_abi))
282     CC_X86RegCall, // __attribute__((regcall))
283     CC_AAPCS,       // __attribute__((pcs("aapcs")))
284     CC_AAPCS_VFP,   // __attribute__((pcs("aapcs-vfp")))
285     CC_IntelOclBicc, // __attribute__((intel_ocl_bicc))
286     CC_SpirFunction, // default for OpenCL functions on SPIR target
287     CC_OpenCLKernel, // inferred for OpenCL kernels
288     CC_Swift,        // __attribute__((swiftcall))
289     CC_SwiftAsync,        // __attribute__((swiftasynccall))
290     CC_PreserveMost, // __attribute__((preserve_most))
291     CC_PreserveAll,  // __attribute__((preserve_all))
292     CC_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))
293     CC_AArch64SVEPCS, // __attribute__((aarch64_sve_pcs))
294     CC_AMDGPUKernelCall, // __attribute__((amdgpu_kernel))
295     CC_M68kRTD,       // __attribute__((m68k_rtd))
296   };
297 
298   /// Checks whether the given calling convention supports variadic
299   /// calls. Unprototyped calls also use the variadic call rules.
supportsVariadicCall(CallingConv CC)300   inline bool supportsVariadicCall(CallingConv CC) {
301     switch (CC) {
302     case CC_X86StdCall:
303     case CC_X86FastCall:
304     case CC_X86ThisCall:
305     case CC_X86RegCall:
306     case CC_X86Pascal:
307     case CC_X86VectorCall:
308     case CC_SpirFunction:
309     case CC_OpenCLKernel:
310     case CC_Swift:
311     case CC_SwiftAsync:
312     case CC_M68kRTD:
313       return false;
314     default:
315       return true;
316     }
317   }
318 
319   /// The storage duration for an object (per C++ [basic.stc]).
320   enum StorageDuration {
321     SD_FullExpression, ///< Full-expression storage duration (for temporaries).
322     SD_Automatic,      ///< Automatic storage duration (most local variables).
323     SD_Thread,         ///< Thread storage duration.
324     SD_Static,         ///< Static storage duration.
325     SD_Dynamic         ///< Dynamic storage duration.
326   };
327 
328   /// Describes the nullability of a particular type.
329   enum class NullabilityKind : uint8_t {
330     /// Values of this type can never be null.
331     NonNull = 0,
332     /// Values of this type can be null.
333     Nullable,
334     /// Whether values of this type can be null is (explicitly)
335     /// unspecified. This captures a (fairly rare) case where we
336     /// can't conclude anything about the nullability of the type even
337     /// though it has been considered.
338     Unspecified,
339     // Generally behaves like Nullable, except when used in a block parameter
340     // that was imported into a swift async method. There, swift will assume
341     // that the parameter can get null even if no error occurred. _Nullable
342     // parameters are assumed to only get null on error.
343     NullableResult,
344   };
345   /// Prints human-readable debug representation.
346   llvm::raw_ostream &operator<<(llvm::raw_ostream&, NullabilityKind);
347 
348   /// Return true if \p L has a weaker nullability annotation than \p R. The
349   /// ordering is: Unspecified < Nullable < NonNull.
hasWeakerNullability(NullabilityKind L,NullabilityKind R)350   inline bool hasWeakerNullability(NullabilityKind L, NullabilityKind R) {
351     return uint8_t(L) > uint8_t(R);
352   }
353 
354   /// Retrieve the spelling of the given nullability kind.
355   llvm::StringRef getNullabilitySpelling(NullabilityKind kind,
356                                          bool isContextSensitive = false);
357 
358   /// Kinds of parameter ABI.
359   enum class ParameterABI {
360     /// This parameter uses ordinary ABI rules for its type.
361     Ordinary,
362 
363     /// This parameter (which must have pointer type) is a Swift
364     /// indirect result parameter.
365     SwiftIndirectResult,
366 
367     /// This parameter (which must have pointer-to-pointer type) uses
368     /// the special Swift error-result ABI treatment.  There can be at
369     /// most one parameter on a given function that uses this treatment.
370     SwiftErrorResult,
371 
372     /// This parameter (which must have pointer type) uses the special
373     /// Swift context-pointer ABI treatment.  There can be at
374     /// most one parameter on a given function that uses this treatment.
375     SwiftContext,
376 
377     /// This parameter (which must have pointer type) uses the special
378     /// Swift asynchronous context-pointer ABI treatment.  There can be at
379     /// most one parameter on a given function that uses this treatment.
380     SwiftAsyncContext,
381   };
382 
383   /// Assigned inheritance model for a class in the MS C++ ABI. Must match order
384   /// of spellings in MSInheritanceAttr.
385   enum class MSInheritanceModel {
386     Single = 0,
387     Multiple = 1,
388     Virtual = 2,
389     Unspecified = 3,
390   };
391 
392   llvm::StringRef getParameterABISpelling(ParameterABI kind);
393 
getAccessSpelling(AccessSpecifier AS)394   inline llvm::StringRef getAccessSpelling(AccessSpecifier AS) {
395     switch (AS) {
396     case AccessSpecifier::AS_public:
397       return "public";
398     case AccessSpecifier::AS_protected:
399       return "protected";
400     case AccessSpecifier::AS_private:
401       return "private";
402     case AccessSpecifier::AS_none:
403       return {};
404     }
405     llvm_unreachable("Unknown AccessSpecifier");
406   }
407 } // end namespace clang
408 
409 #endif // LLVM_CLANG_BASIC_SPECIFIERS_H
410