1 //===--- Attr.h - Classes for representing attributes ----------*- 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 //  This file defines the Attr interface and subclasses.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_AST_ATTR_H
14 #define LLVM_CLANG_AST_ATTR_H
15 
16 #include "clang/AST/ASTFwd.h"
17 #include "clang/AST/AttrIterator.h"
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/Type.h"
20 #include "clang/Basic/AttrKinds.h"
21 #include "clang/Basic/AttributeCommonInfo.h"
22 #include "clang/Basic/LangOptions.h"
23 #include "clang/Basic/LLVM.h"
24 #include "clang/Basic/OpenMPKinds.h"
25 #include "clang/Basic/Sanitizers.h"
26 #include "clang/Basic/SourceLocation.h"
27 #include "llvm/ADT/StringSwitch.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/VersionTuple.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include <algorithm>
32 #include <cassert>
33 
34 namespace clang {
35 class ASTContext;
36 class AttributeCommonInfo;
37 class IdentifierInfo;
38 class ObjCInterfaceDecl;
39 class Expr;
40 class QualType;
41 class FunctionDecl;
42 class TypeSourceInfo;
43 class OMPTraitInfo;
44 
45 /// Attr - This represents one attribute.
46 class Attr : public AttributeCommonInfo {
47 private:
48   unsigned AttrKind : 16;
49 
50 protected:
51   /// An index into the spelling list of an
52   /// attribute defined in Attr.td file.
53   unsigned Inherited : 1;
54   unsigned IsPackExpansion : 1;
55   unsigned Implicit : 1;
56   // FIXME: These are properties of the attribute kind, not state for this
57   // instance of the attribute.
58   unsigned IsLateParsed : 1;
59   unsigned InheritEvenIfAlreadyPresent : 1;
60 
new(size_t bytes)61   void *operator new(size_t bytes) noexcept {
62     llvm_unreachable("Attrs cannot be allocated with regular 'new'.");
63   }
delete(void * data)64   void operator delete(void *data) noexcept {
65     llvm_unreachable("Attrs cannot be released with regular 'delete'.");
66   }
67 
68 public:
69   // Forward so that the regular new and delete do not hide global ones.
70   void *operator new(size_t Bytes, ASTContext &C,
71                      size_t Alignment = 8) noexcept {
72     return ::operator new(Bytes, C, Alignment);
73   }
delete(void * Ptr,ASTContext & C,size_t Alignment)74   void operator delete(void *Ptr, ASTContext &C, size_t Alignment) noexcept {
75     return ::operator delete(Ptr, C, Alignment);
76   }
77 
78 protected:
Attr(ASTContext & Context,const AttributeCommonInfo & CommonInfo,attr::Kind AK,bool IsLateParsed)79   Attr(ASTContext &Context, const AttributeCommonInfo &CommonInfo,
80        attr::Kind AK, bool IsLateParsed)
81       : AttributeCommonInfo(CommonInfo), AttrKind(AK), Inherited(false),
82         IsPackExpansion(false), Implicit(false), IsLateParsed(IsLateParsed),
83         InheritEvenIfAlreadyPresent(false) {}
84 
85 public:
getKind()86   attr::Kind getKind() const { return static_cast<attr::Kind>(AttrKind); }
87 
getSpellingListIndex()88   unsigned getSpellingListIndex() const {
89     return getAttributeSpellingListIndex();
90   }
91   const char *getSpelling() const;
92 
getLocation()93   SourceLocation getLocation() const { return getRange().getBegin(); }
94 
isInherited()95   bool isInherited() const { return Inherited; }
96 
97   /// Returns true if the attribute has been implicitly created instead
98   /// of explicitly written by the user.
isImplicit()99   bool isImplicit() const { return Implicit; }
setImplicit(bool I)100   void setImplicit(bool I) { Implicit = I; }
101 
setPackExpansion(bool PE)102   void setPackExpansion(bool PE) { IsPackExpansion = PE; }
isPackExpansion()103   bool isPackExpansion() const { return IsPackExpansion; }
104 
105   // Clone this attribute.
106   Attr *clone(ASTContext &C) const;
107 
isLateParsed()108   bool isLateParsed() const { return IsLateParsed; }
109 
110   // Pretty print this attribute.
111   void printPretty(raw_ostream &OS, const PrintingPolicy &Policy) const;
112 };
113 
114 class TypeAttr : public Attr {
115 protected:
TypeAttr(ASTContext & Context,const AttributeCommonInfo & CommonInfo,attr::Kind AK,bool IsLateParsed)116   TypeAttr(ASTContext &Context, const AttributeCommonInfo &CommonInfo,
117            attr::Kind AK, bool IsLateParsed)
118       : Attr(Context, CommonInfo, AK, IsLateParsed) {}
119 
120 public:
classof(const Attr * A)121   static bool classof(const Attr *A) {
122     return A->getKind() >= attr::FirstTypeAttr &&
123            A->getKind() <= attr::LastTypeAttr;
124   }
125 };
126 
127 class StmtAttr : public Attr {
128 protected:
StmtAttr(ASTContext & Context,const AttributeCommonInfo & CommonInfo,attr::Kind AK,bool IsLateParsed)129   StmtAttr(ASTContext &Context, const AttributeCommonInfo &CommonInfo,
130            attr::Kind AK, bool IsLateParsed)
131       : Attr(Context, CommonInfo, AK, IsLateParsed) {}
132 
133 public:
classof(const Attr * A)134   static bool classof(const Attr *A) {
135     return A->getKind() >= attr::FirstStmtAttr &&
136            A->getKind() <= attr::LastStmtAttr;
137   }
138 };
139 
140 class InheritableAttr : public Attr {
141 protected:
InheritableAttr(ASTContext & Context,const AttributeCommonInfo & CommonInfo,attr::Kind AK,bool IsLateParsed,bool InheritEvenIfAlreadyPresent)142   InheritableAttr(ASTContext &Context, const AttributeCommonInfo &CommonInfo,
143                   attr::Kind AK, bool IsLateParsed,
144                   bool InheritEvenIfAlreadyPresent)
145       : Attr(Context, CommonInfo, AK, IsLateParsed) {
146     this->InheritEvenIfAlreadyPresent = InheritEvenIfAlreadyPresent;
147   }
148 
149 public:
setInherited(bool I)150   void setInherited(bool I) { Inherited = I; }
151 
152   /// Should this attribute be inherited from a prior declaration even if it's
153   /// explicitly provided in the current declaration?
shouldInheritEvenIfAlreadyPresent()154   bool shouldInheritEvenIfAlreadyPresent() const {
155     return InheritEvenIfAlreadyPresent;
156   }
157 
158   // Implement isa/cast/dyncast/etc.
classof(const Attr * A)159   static bool classof(const Attr *A) {
160     return A->getKind() >= attr::FirstInheritableAttr &&
161            A->getKind() <= attr::LastInheritableAttr;
162   }
163 };
164 
165 class InheritableParamAttr : public InheritableAttr {
166 protected:
InheritableParamAttr(ASTContext & Context,const AttributeCommonInfo & CommonInfo,attr::Kind AK,bool IsLateParsed,bool InheritEvenIfAlreadyPresent)167   InheritableParamAttr(ASTContext &Context,
168                        const AttributeCommonInfo &CommonInfo, attr::Kind AK,
169                        bool IsLateParsed, bool InheritEvenIfAlreadyPresent)
170       : InheritableAttr(Context, CommonInfo, AK, IsLateParsed,
171                         InheritEvenIfAlreadyPresent) {}
172 
173 public:
174   // Implement isa/cast/dyncast/etc.
classof(const Attr * A)175   static bool classof(const Attr *A) {
176     return A->getKind() >= attr::FirstInheritableParamAttr &&
177            A->getKind() <= attr::LastInheritableParamAttr;
178   }
179 };
180 
181 /// A parameter attribute which changes the argument-passing ABI rule
182 /// for the parameter.
183 class ParameterABIAttr : public InheritableParamAttr {
184 protected:
ParameterABIAttr(ASTContext & Context,const AttributeCommonInfo & CommonInfo,attr::Kind AK,bool IsLateParsed,bool InheritEvenIfAlreadyPresent)185   ParameterABIAttr(ASTContext &Context, const AttributeCommonInfo &CommonInfo,
186                    attr::Kind AK, bool IsLateParsed,
187                    bool InheritEvenIfAlreadyPresent)
188       : InheritableParamAttr(Context, CommonInfo, AK, IsLateParsed,
189                              InheritEvenIfAlreadyPresent) {}
190 
191 public:
getABI()192   ParameterABI getABI() const {
193     switch (getKind()) {
194     case attr::SwiftContext:
195       return ParameterABI::SwiftContext;
196     case attr::SwiftErrorResult:
197       return ParameterABI::SwiftErrorResult;
198     case attr::SwiftIndirectResult:
199       return ParameterABI::SwiftIndirectResult;
200     default:
201       llvm_unreachable("bad parameter ABI attribute kind");
202     }
203   }
204 
classof(const Attr * A)205   static bool classof(const Attr *A) {
206     return A->getKind() >= attr::FirstParameterABIAttr &&
207            A->getKind() <= attr::LastParameterABIAttr;
208    }
209 };
210 
211 /// A single parameter index whose accessors require each use to make explicit
212 /// the parameter index encoding needed.
213 class ParamIdx {
214   // Idx is exposed only via accessors that specify specific encodings.
215   unsigned Idx : 30;
216   unsigned HasThis : 1;
217   unsigned IsValid : 1;
218 
assertComparable(const ParamIdx & I)219   void assertComparable(const ParamIdx &I) const {
220     assert(isValid() && I.isValid() &&
221            "ParamIdx must be valid to be compared");
222     // It's possible to compare indices from separate functions, but so far
223     // it's not proven useful.  Moreover, it might be confusing because a
224     // comparison on the results of getASTIndex might be inconsistent with a
225     // comparison on the ParamIdx objects themselves.
226     assert(HasThis == I.HasThis &&
227            "ParamIdx must be for the same function to be compared");
228   }
229 
230 public:
231   /// Construct an invalid parameter index (\c isValid returns false and
232   /// accessors fail an assert).
ParamIdx()233   ParamIdx() : Idx(0), HasThis(false), IsValid(false) {}
234 
235   /// \param Idx is the parameter index as it is normally specified in
236   /// attributes in the source: one-origin including any C++ implicit this
237   /// parameter.
238   ///
239   /// \param D is the declaration containing the parameters.  It is used to
240   /// determine if there is a C++ implicit this parameter.
ParamIdx(unsigned Idx,const Decl * D)241   ParamIdx(unsigned Idx, const Decl *D)
242       : Idx(Idx), HasThis(false), IsValid(true) {
243     assert(Idx >= 1 && "Idx must be one-origin");
244     if (const auto *FD = dyn_cast<FunctionDecl>(D))
245       HasThis = FD->isCXXInstanceMember();
246   }
247 
248   /// A type into which \c ParamIdx can be serialized.
249   ///
250   /// A static assertion that it's of the correct size follows the \c ParamIdx
251   /// class definition.
252   typedef uint32_t SerialType;
253 
254   /// Produce a representation that can later be passed to \c deserialize to
255   /// construct an equivalent \c ParamIdx.
serialize()256   SerialType serialize() const {
257     return *reinterpret_cast<const SerialType *>(this);
258   }
259 
260   /// Construct from a result from \c serialize.
deserialize(SerialType S)261   static ParamIdx deserialize(SerialType S) {
262     // Using this two-step static_cast via void * instead of reinterpret_cast
263     // silences a -Wstrict-aliasing false positive from GCC7 and earlier.
264     void *ParamIdxPtr = static_cast<void *>(&S);
265     ParamIdx P(*static_cast<ParamIdx *>(ParamIdxPtr));
266     assert((!P.IsValid || P.Idx >= 1) && "valid Idx must be one-origin");
267     return P;
268   }
269 
270   /// Is this parameter index valid?
isValid()271   bool isValid() const { return IsValid; }
272 
273   /// Get the parameter index as it would normally be encoded for attributes at
274   /// the source level of representation: one-origin including any C++ implicit
275   /// this parameter.
276   ///
277   /// This encoding thus makes sense for diagnostics, pretty printing, and
278   /// constructing new attributes from a source-like specification.
getSourceIndex()279   unsigned getSourceIndex() const {
280     assert(isValid() && "ParamIdx must be valid");
281     return Idx;
282   }
283 
284   /// Get the parameter index as it would normally be encoded at the AST level
285   /// of representation: zero-origin not including any C++ implicit this
286   /// parameter.
287   ///
288   /// This is the encoding primarily used in Sema.  However, in diagnostics,
289   /// Sema uses \c getSourceIndex instead.
getASTIndex()290   unsigned getASTIndex() const {
291     assert(isValid() && "ParamIdx must be valid");
292     assert(Idx >= 1 + HasThis &&
293            "stored index must be base-1 and not specify C++ implicit this");
294     return Idx - 1 - HasThis;
295   }
296 
297   /// Get the parameter index as it would normally be encoded at the LLVM level
298   /// of representation: zero-origin including any C++ implicit this parameter.
299   ///
300   /// This is the encoding primarily used in CodeGen.
getLLVMIndex()301   unsigned getLLVMIndex() const {
302     assert(isValid() && "ParamIdx must be valid");
303     assert(Idx >= 1 && "stored index must be base-1");
304     return Idx - 1;
305   }
306 
307   bool operator==(const ParamIdx &I) const {
308     assertComparable(I);
309     return Idx == I.Idx;
310   }
311   bool operator!=(const ParamIdx &I) const {
312     assertComparable(I);
313     return Idx != I.Idx;
314   }
315   bool operator<(const ParamIdx &I) const {
316     assertComparable(I);
317     return Idx < I.Idx;
318   }
319   bool operator>(const ParamIdx &I) const {
320     assertComparable(I);
321     return Idx > I.Idx;
322   }
323   bool operator<=(const ParamIdx &I) const {
324     assertComparable(I);
325     return Idx <= I.Idx;
326   }
327   bool operator>=(const ParamIdx &I) const {
328     assertComparable(I);
329     return Idx >= I.Idx;
330   }
331 };
332 
333 static_assert(sizeof(ParamIdx) == sizeof(ParamIdx::SerialType),
334               "ParamIdx does not fit its serialization type");
335 
336 /// Contains information gathered from parsing the contents of TargetAttr.
337 struct ParsedTargetAttr {
338   std::vector<std::string> Features;
339   StringRef Architecture;
340   StringRef Tune;
341   StringRef BranchProtection;
342   bool DuplicateArchitecture = false;
343   bool DuplicateTune = false;
344   bool operator ==(const ParsedTargetAttr &Other) const {
345     return DuplicateArchitecture == Other.DuplicateArchitecture &&
346            DuplicateTune == Other.DuplicateTune &&
347            Architecture == Other.Architecture &&
348            Tune == Other.Tune &&
349            BranchProtection == Other.BranchProtection &&
350            Features == Other.Features;
351   }
352 };
353 
354 #include "clang/AST/Attrs.inc"
355 
356 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
357                                              const Attr *At) {
358   DB.AddTaggedVal(reinterpret_cast<intptr_t>(At),
359                   DiagnosticsEngine::ak_attr);
360   return DB;
361 }
362 }  // end namespace clang
363 
364 #endif
365