1//===- ParsedAttrInfo.h - Info needed to parse an attribute -----*- 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 ParsedAttrInfo class, which dictates how to
10// parse an attribute. This class is the one that plugins derive to
11// define a new attribute.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_BASIC_PARSEDATTRINFO_H
16#define LLVM_CLANG_BASIC_PARSEDATTRINFO_H
17
18#include "clang/Basic/AttrSubjectMatchRules.h"
19#include "clang/Basic/AttributeCommonInfo.h"
20#include "llvm/ADT/ArrayRef.h"
21#include "llvm/Support/Registry.h"
22#include <climits>
23#include <list>
24
25namespace clang {
26
27class Decl;
28class LangOptions;
29class ParsedAttr;
30class Sema;
31class Stmt;
32class TargetInfo;
33
34struct ParsedAttrInfo {
35  /// Corresponds to the Kind enum.
36  LLVM_PREFERRED_TYPE(AttributeCommonInfo::Kind)
37  unsigned AttrKind : 16;
38  /// The number of required arguments of this attribute.
39  unsigned NumArgs : 4;
40  /// The number of optional arguments of this attributes.
41  unsigned OptArgs : 4;
42  /// The number of non-fake arguments specified in the attribute definition.
43  unsigned NumArgMembers : 4;
44  /// True if the parsing does not match the semantic content.
45  LLVM_PREFERRED_TYPE(bool)
46  unsigned HasCustomParsing : 1;
47  // True if this attribute accepts expression parameter pack expansions.
48  LLVM_PREFERRED_TYPE(bool)
49  unsigned AcceptsExprPack : 1;
50  /// True if this attribute is only available for certain targets.
51  LLVM_PREFERRED_TYPE(bool)
52  unsigned IsTargetSpecific : 1;
53  /// True if this attribute applies to types.
54  LLVM_PREFERRED_TYPE(bool)
55  unsigned IsType : 1;
56  /// True if this attribute applies to statements.
57  LLVM_PREFERRED_TYPE(bool)
58  unsigned IsStmt : 1;
59  /// True if this attribute has any spellings that are known to gcc.
60  LLVM_PREFERRED_TYPE(bool)
61  unsigned IsKnownToGCC : 1;
62  /// True if this attribute is supported by #pragma clang attribute.
63  LLVM_PREFERRED_TYPE(bool)
64  unsigned IsSupportedByPragmaAttribute : 1;
65  /// The syntaxes supported by this attribute and how they're spelled.
66  struct Spelling {
67    AttributeCommonInfo::Syntax Syntax;
68    const char *NormalizedFullName;
69  };
70  ArrayRef<Spelling> Spellings;
71  // The names of the known arguments of this attribute.
72  ArrayRef<const char *> ArgNames;
73
74protected:
75  constexpr ParsedAttrInfo(AttributeCommonInfo::Kind AttrKind =
76                               AttributeCommonInfo::NoSemaHandlerAttribute)
77      : AttrKind(AttrKind), NumArgs(0), OptArgs(0), NumArgMembers(0),
78        HasCustomParsing(0), AcceptsExprPack(0), IsTargetSpecific(0), IsType(0),
79        IsStmt(0), IsKnownToGCC(0), IsSupportedByPragmaAttribute(0) {}
80
81  constexpr ParsedAttrInfo(AttributeCommonInfo::Kind AttrKind, unsigned NumArgs,
82                           unsigned OptArgs, unsigned NumArgMembers,
83                           unsigned HasCustomParsing, unsigned AcceptsExprPack,
84                           unsigned IsTargetSpecific, unsigned IsType,
85                           unsigned IsStmt, unsigned IsKnownToGCC,
86                           unsigned IsSupportedByPragmaAttribute,
87                           ArrayRef<Spelling> Spellings,
88                           ArrayRef<const char *> ArgNames)
89      : AttrKind(AttrKind), NumArgs(NumArgs), OptArgs(OptArgs),
90        NumArgMembers(NumArgMembers), HasCustomParsing(HasCustomParsing),
91        AcceptsExprPack(AcceptsExprPack), IsTargetSpecific(IsTargetSpecific),
92        IsType(IsType), IsStmt(IsStmt), IsKnownToGCC(IsKnownToGCC),
93        IsSupportedByPragmaAttribute(IsSupportedByPragmaAttribute),
94        Spellings(Spellings), ArgNames(ArgNames) {}
95
96public:
97  virtual ~ParsedAttrInfo() = default;
98
99  /// Check if this attribute has specified spelling.
100  bool hasSpelling(AttributeCommonInfo::Syntax Syntax, StringRef Name) const {
101    return llvm::any_of(Spellings, [&](const Spelling &S) {
102      return (S.Syntax == Syntax && S.NormalizedFullName == Name);
103    });
104  }
105
106  /// Check if this attribute appertains to D, and issue a diagnostic if not.
107  virtual bool diagAppertainsToDecl(Sema &S, const ParsedAttr &Attr,
108                                    const Decl *D) const {
109    return true;
110  }
111  /// Check if this attribute appertains to St, and issue a diagnostic if not.
112  virtual bool diagAppertainsToStmt(Sema &S, const ParsedAttr &Attr,
113                                    const Stmt *St) const {
114    return true;
115  }
116  /// Check if the given attribute is mutually exclusive with other attributes
117  /// already applied to the given declaration.
118  virtual bool diagMutualExclusion(Sema &S, const ParsedAttr &A,
119                                   const Decl *D) const {
120    return true;
121  }
122  /// Check if this attribute is allowed by the language we are compiling.
123  virtual bool acceptsLangOpts(const LangOptions &LO) const { return true; }
124
125  /// Check if this attribute is allowed when compiling for the given target.
126  virtual bool existsInTarget(const TargetInfo &Target) const { return true; }
127
128  /// Check if this attribute's spelling is allowed when compiling for the given
129  /// target.
130  virtual bool spellingExistsInTarget(const TargetInfo &Target,
131                                      const unsigned SpellingListIndex) const {
132    return true;
133  }
134
135  /// Convert the spelling index of Attr to a semantic spelling enum value.
136  virtual unsigned
137  spellingIndexToSemanticSpelling(const ParsedAttr &Attr) const {
138    return UINT_MAX;
139  }
140  /// Returns true if the specified parameter index for this attribute in
141  /// Attr.td is an ExprArgument or VariadicExprArgument, or a subclass thereof;
142  /// returns false otherwise.
143  virtual bool isParamExpr(size_t N) const { return false; }
144  /// Populate Rules with the match rules of this attribute.
145  virtual void getPragmaAttributeMatchRules(
146      llvm::SmallVectorImpl<std::pair<attr::SubjectMatchRule, bool>> &Rules,
147      const LangOptions &LangOpts) const {}
148
149  enum AttrHandling { NotHandled, AttributeApplied, AttributeNotApplied };
150  /// If this ParsedAttrInfo knows how to handle this ParsedAttr applied to this
151  /// Decl then do so and return either AttributeApplied if it was applied or
152  /// AttributeNotApplied if it wasn't. Otherwise return NotHandled.
153  virtual AttrHandling handleDeclAttribute(Sema &S, Decl *D,
154                                           const ParsedAttr &Attr) const {
155    return NotHandled;
156  }
157
158  static const ParsedAttrInfo &get(const AttributeCommonInfo &A);
159  static ArrayRef<const ParsedAttrInfo *> getAllBuiltin();
160};
161
162typedef llvm::Registry<ParsedAttrInfo> ParsedAttrInfoRegistry;
163
164const std::list<std::unique_ptr<ParsedAttrInfo>> &getAttributePluginInstances();
165
166} // namespace clang
167
168#endif // LLVM_CLANG_BASIC_PARSEDATTRINFO_H
169