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 class ConstexprSpecKind { Unspecified, Constexpr, Consteval, Constinit };
33 
34   /// In an if statement, this denotes whether the statement is
35   /// a constexpr or consteval if statement.
36   enum class IfStatementKind : unsigned {
37     Ordinary,
38     Constexpr,
39     ConstevalNonNegated,
40     ConstevalNegated
41   };
42 
43   /// Specifies the width of a type, e.g., short, long, or long long.
44   enum class TypeSpecifierWidth { Unspecified, Short, Long, LongLong };
45 
46   /// Specifies the signedness of a type, e.g., signed or unsigned.
47   enum class TypeSpecifierSign { Unspecified, Signed, Unsigned };
48 
49   enum class TypeSpecifiersPipe { Unspecified, Pipe };
50 
51   /// Specifies the kind of type.
52   enum TypeSpecifierType {
53     TST_unspecified,
54     TST_void,
55     TST_char,
56     TST_wchar,  // C++ wchar_t
57     TST_char8,  // C++20 char8_t (proposed)
58     TST_char16, // C++11 char16_t
59     TST_char32, // C++11 char32_t
60     TST_int,
61     TST_int128,
62     TST_bitint,  // Bit-precise integer types.
63     TST_half,    // OpenCL half, ARM NEON __fp16
64     TST_Float16, // C11 extension ISO/IEC TS 18661-3
65     TST_Accum,   // ISO/IEC JTC1 SC22 WG14 N1169 Extension
66     TST_Fract,
67     TST_BFloat16,
68     TST_float,
69     TST_double,
70     TST_float128,
71     TST_ibm128,
72     TST_bool,       // _Bool
73     TST_decimal32,  // _Decimal32
74     TST_decimal64,  // _Decimal64
75     TST_decimal128, // _Decimal128
76     TST_enum,
77     TST_union,
78     TST_struct,
79     TST_class,     // C++ class type
80     TST_interface, // C++ (Microsoft-specific) __interface type
81     TST_typename,  // Typedef, C++ class-name or enum name, etc.
82     TST_typeofType,        // C2x (and GNU extension) typeof(type-name)
83     TST_typeofExpr,        // C2x (and GNU extension) typeof(expression)
84     TST_typeof_unqualType, // C2x typeof_unqual(type-name)
85     TST_typeof_unqualExpr, // C2x typeof_unqual(expression)
86     TST_decltype, // C++11 decltype
87 #define TRANSFORM_TYPE_TRAIT_DEF(_, Trait) TST_##Trait,
88 #include "clang/Basic/TransformTypeTraits.def"
89     TST_auto,            // C++11 auto
90     TST_decltype_auto,   // C++1y decltype(auto)
91     TST_auto_type,       // __auto_type extension
92     TST_unknown_anytype, // __unknown_anytype extension
93     TST_atomic,          // C11 _Atomic
94 #define GENERIC_IMAGE_TYPE(ImgType, Id) TST_##ImgType##_t, // OpenCL image types
95 #include "clang/Basic/OpenCLImageTypes.def"
96     TST_error // erroneous type
97   };
98 
99   /// Structure that packs information about the type specifiers that
100   /// were written in a particular type specifier sequence.
101   struct WrittenBuiltinSpecs {
102     static_assert(TST_error < 1 << 7, "Type bitfield not wide enough for TST");
103     /*DeclSpec::TST*/ unsigned Type : 7;
104     /*DeclSpec::TSS*/ unsigned Sign  : 2;
105     /*TypeSpecifierWidth*/ unsigned Width : 2;
106     unsigned ModeAttr : 1;
107   };
108 
109   /// A C++ access specifier (public, private, protected), plus the
110   /// special value "none" which means different things in different contexts.
111   enum AccessSpecifier {
112     AS_public,
113     AS_protected,
114     AS_private,
115     AS_none
116   };
117 
118   /// The categorization of expression values, currently following the
119   /// C++11 scheme.
120   enum ExprValueKind {
121     /// A pr-value expression (in the C++11 taxonomy)
122     /// produces a temporary value.
123     VK_PRValue,
124 
125     /// An l-value expression is a reference to an object with
126     /// independent storage.
127     VK_LValue,
128 
129     /// An x-value expression is a reference to an object with
130     /// independent storage but which can be "moved", i.e.
131     /// efficiently cannibalized for its resources.
132     VK_XValue
133   };
134 
135   /// A further classification of the kind of object referenced by an
136   /// l-value or x-value.
137   enum ExprObjectKind {
138     /// An ordinary object is located at an address in memory.
139     OK_Ordinary,
140 
141     /// A bitfield object is a bitfield on a C or C++ record.
142     OK_BitField,
143 
144     /// A vector component is an element or range of elements on a vector.
145     OK_VectorComponent,
146 
147     /// An Objective-C property is a logical field of an Objective-C
148     /// object which is read and written via Objective-C method calls.
149     OK_ObjCProperty,
150 
151     /// An Objective-C array/dictionary subscripting which reads an
152     /// object or writes at the subscripted array/dictionary element via
153     /// Objective-C method calls.
154     OK_ObjCSubscript,
155 
156     /// A matrix component is a single element of a matrix.
157     OK_MatrixComponent
158   };
159 
160   /// The reason why a DeclRefExpr does not constitute an odr-use.
161   enum NonOdrUseReason {
162     /// This is an odr-use.
163     NOUR_None = 0,
164     /// This name appears in an unevaluated operand.
165     NOUR_Unevaluated,
166     /// This name appears as a potential result of an lvalue-to-rvalue
167     /// conversion that is a constant expression.
168     NOUR_Constant,
169     /// This name appears as a potential result of a discarded value
170     /// expression.
171     NOUR_Discarded,
172   };
173 
174   /// Describes the kind of template specialization that a
175   /// particular template specialization declaration represents.
176   enum TemplateSpecializationKind {
177     /// This template specialization was formed from a template-id but
178     /// has not yet been declared, defined, or instantiated.
179     TSK_Undeclared = 0,
180     /// This template specialization was implicitly instantiated from a
181     /// template. (C++ [temp.inst]).
182     TSK_ImplicitInstantiation,
183     /// This template specialization was declared or defined by an
184     /// explicit specialization (C++ [temp.expl.spec]) or partial
185     /// specialization (C++ [temp.class.spec]).
186     TSK_ExplicitSpecialization,
187     /// This template specialization was instantiated from a template
188     /// due to an explicit instantiation declaration request
189     /// (C++11 [temp.explicit]).
190     TSK_ExplicitInstantiationDeclaration,
191     /// This template specialization was instantiated from a template
192     /// due to an explicit instantiation definition request
193     /// (C++ [temp.explicit]).
194     TSK_ExplicitInstantiationDefinition
195   };
196 
197   /// Determine whether this template specialization kind refers
198   /// to an instantiation of an entity (as opposed to a non-template or
199   /// an explicit specialization).
isTemplateInstantiation(TemplateSpecializationKind Kind)200   inline bool isTemplateInstantiation(TemplateSpecializationKind Kind) {
201     return Kind != TSK_Undeclared && Kind != TSK_ExplicitSpecialization;
202   }
203 
204   /// True if this template specialization kind is an explicit
205   /// specialization, explicit instantiation declaration, or explicit
206   /// instantiation definition.
isTemplateExplicitInstantiationOrSpecialization(TemplateSpecializationKind Kind)207   inline bool isTemplateExplicitInstantiationOrSpecialization(
208       TemplateSpecializationKind Kind) {
209     switch (Kind) {
210     case TSK_ExplicitSpecialization:
211     case TSK_ExplicitInstantiationDeclaration:
212     case TSK_ExplicitInstantiationDefinition:
213       return true;
214 
215     case TSK_Undeclared:
216     case TSK_ImplicitInstantiation:
217       return false;
218     }
219     llvm_unreachable("bad template specialization kind");
220   }
221 
222   /// Thread storage-class-specifier.
223   enum ThreadStorageClassSpecifier {
224     TSCS_unspecified,
225     /// GNU __thread.
226     TSCS___thread,
227     /// C++11 thread_local. Implies 'static' at block scope, but not at
228     /// class scope.
229     TSCS_thread_local,
230     /// C11 _Thread_local. Must be combined with either 'static' or 'extern'
231     /// if used at block scope.
232     TSCS__Thread_local
233   };
234 
235   /// Storage classes.
236   enum StorageClass {
237     // These are legal on both functions and variables.
238     SC_None,
239     SC_Extern,
240     SC_Static,
241     SC_PrivateExtern,
242 
243     // These are only legal on variables.
244     SC_Auto,
245     SC_Register
246   };
247 
248   /// Checks whether the given storage class is legal for functions.
isLegalForFunction(StorageClass SC)249   inline bool isLegalForFunction(StorageClass SC) {
250     return SC <= SC_PrivateExtern;
251   }
252 
253   /// Checks whether the given storage class is legal for variables.
isLegalForVariable(StorageClass SC)254   inline bool isLegalForVariable(StorageClass SC) {
255     return true;
256   }
257 
258   /// In-class initialization styles for non-static data members.
259   enum InClassInitStyle {
260     ICIS_NoInit,   ///< No in-class initializer.
261     ICIS_CopyInit, ///< Copy initialization.
262     ICIS_ListInit  ///< Direct list-initialization.
263   };
264 
265   /// CallingConv - Specifies the calling convention that a function uses.
266   enum CallingConv {
267     CC_C,           // __attribute__((cdecl))
268     CC_X86StdCall,  // __attribute__((stdcall))
269     CC_X86FastCall, // __attribute__((fastcall))
270     CC_X86ThisCall, // __attribute__((thiscall))
271     CC_X86VectorCall, // __attribute__((vectorcall))
272     CC_X86Pascal,   // __attribute__((pascal))
273     CC_Win64,       // __attribute__((ms_abi))
274     CC_X86_64SysV,  // __attribute__((sysv_abi))
275     CC_X86RegCall, // __attribute__((regcall))
276     CC_AAPCS,       // __attribute__((pcs("aapcs")))
277     CC_AAPCS_VFP,   // __attribute__((pcs("aapcs-vfp")))
278     CC_IntelOclBicc, // __attribute__((intel_ocl_bicc))
279     CC_SpirFunction, // default for OpenCL functions on SPIR target
280     CC_OpenCLKernel, // inferred for OpenCL kernels
281     CC_Swift,        // __attribute__((swiftcall))
282     CC_SwiftAsync,        // __attribute__((swiftasynccall))
283     CC_PreserveMost, // __attribute__((preserve_most))
284     CC_PreserveAll,  // __attribute__((preserve_all))
285     CC_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))
286     CC_AArch64SVEPCS, // __attribute__((aarch64_sve_pcs))
287     CC_AMDGPUKernelCall, // __attribute__((amdgpu_kernel))
288   };
289 
290   /// Checks whether the given calling convention supports variadic
291   /// calls. Unprototyped calls also use the variadic call rules.
supportsVariadicCall(CallingConv CC)292   inline bool supportsVariadicCall(CallingConv CC) {
293     switch (CC) {
294     case CC_X86StdCall:
295     case CC_X86FastCall:
296     case CC_X86ThisCall:
297     case CC_X86RegCall:
298     case CC_X86Pascal:
299     case CC_X86VectorCall:
300     case CC_SpirFunction:
301     case CC_OpenCLKernel:
302     case CC_Swift:
303     case CC_SwiftAsync:
304       return false;
305     default:
306       return true;
307     }
308   }
309 
310   /// The storage duration for an object (per C++ [basic.stc]).
311   enum StorageDuration {
312     SD_FullExpression, ///< Full-expression storage duration (for temporaries).
313     SD_Automatic,      ///< Automatic storage duration (most local variables).
314     SD_Thread,         ///< Thread storage duration.
315     SD_Static,         ///< Static storage duration.
316     SD_Dynamic         ///< Dynamic storage duration.
317   };
318 
319   /// Describes the nullability of a particular type.
320   enum class NullabilityKind : uint8_t {
321     /// Values of this type can never be null.
322     NonNull = 0,
323     /// Values of this type can be null.
324     Nullable,
325     /// Whether values of this type can be null is (explicitly)
326     /// unspecified. This captures a (fairly rare) case where we
327     /// can't conclude anything about the nullability of the type even
328     /// though it has been considered.
329     Unspecified,
330     // Generally behaves like Nullable, except when used in a block parameter
331     // that was imported into a swift async method. There, swift will assume
332     // that the parameter can get null even if no error occurred. _Nullable
333     // parameters are assumed to only get null on error.
334     NullableResult,
335   };
336 
337   /// Return true if \p L has a weaker nullability annotation than \p R. The
338   /// ordering is: Unspecified < Nullable < NonNull.
hasWeakerNullability(NullabilityKind L,NullabilityKind R)339   inline bool hasWeakerNullability(NullabilityKind L, NullabilityKind R) {
340     return uint8_t(L) > uint8_t(R);
341   }
342 
343   /// Retrieve the spelling of the given nullability kind.
344   llvm::StringRef getNullabilitySpelling(NullabilityKind kind,
345                                          bool isContextSensitive = false);
346 
347   /// Kinds of parameter ABI.
348   enum class ParameterABI {
349     /// This parameter uses ordinary ABI rules for its type.
350     Ordinary,
351 
352     /// This parameter (which must have pointer type) is a Swift
353     /// indirect result parameter.
354     SwiftIndirectResult,
355 
356     /// This parameter (which must have pointer-to-pointer type) uses
357     /// the special Swift error-result ABI treatment.  There can be at
358     /// most one parameter on a given function that uses this treatment.
359     SwiftErrorResult,
360 
361     /// This parameter (which must have pointer type) uses the special
362     /// Swift context-pointer ABI treatment.  There can be at
363     /// most one parameter on a given function that uses this treatment.
364     SwiftContext,
365 
366     /// This parameter (which must have pointer type) uses the special
367     /// Swift asynchronous context-pointer ABI treatment.  There can be at
368     /// most one parameter on a given function that uses this treatment.
369     SwiftAsyncContext,
370   };
371 
372   /// Assigned inheritance model for a class in the MS C++ ABI. Must match order
373   /// of spellings in MSInheritanceAttr.
374   enum class MSInheritanceModel {
375     Single = 0,
376     Multiple = 1,
377     Virtual = 2,
378     Unspecified = 3,
379   };
380 
381   llvm::StringRef getParameterABISpelling(ParameterABI kind);
382 
getAccessSpelling(AccessSpecifier AS)383   inline llvm::StringRef getAccessSpelling(AccessSpecifier AS) {
384     switch (AS) {
385     case AccessSpecifier::AS_public:
386       return "public";
387     case AccessSpecifier::AS_protected:
388       return "protected";
389     case AccessSpecifier::AS_private:
390       return "private";
391     case AccessSpecifier::AS_none:
392       return {};
393     }
394     llvm_unreachable("Unknown AccessSpecifier");
395   }
396 } // end namespace clang
397 
398 #endif // LLVM_CLANG_BASIC_SPECIFIERS_H
399