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Pragma.h
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1 //===- Pragma.h - Pragma registration and handling --------------*- 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 PragmaHandler and PragmaTable interfaces.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_LEX_PRAGMA_H
14 #define LLVM_CLANG_LEX_PRAGMA_H
15 
16 #include "clang/Basic/LLVM.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/ADT/StringRef.h"
20 #include <string>
21 
22 namespace clang {
23 
24 class PragmaNamespace;
25 class Preprocessor;
26 class Token;
27 
28  /**
29  * Describes how the pragma was introduced, e.g., with \#pragma,
30  * _Pragma, or __pragma.
31  */
33  /**
34  * The pragma was introduced via \#pragma.
35  */
37 
38  /**
39  * The pragma was introduced via the C99 _Pragma(string-literal).
40  */
42 
43  /**
44  * The pragma was introduced via the Microsoft
45  * __pragma(token-string).
46  */
48  };
49 
50  /// Describes how and where the pragma was introduced.
54  };
55 
56 /// PragmaHandler - Instances of this interface defined to handle the various
57 /// pragmas that the language front-end uses. Each handler optionally has a
58 /// name (e.g. "pack") and the HandlePragma method is invoked when a pragma with
59 /// that identifier is found. If a handler does not match any of the declared
60 /// pragmas the handler with a null identifier is invoked, if it exists.
61 ///
62 /// Note that the PragmaNamespace class can be used to subdivide pragmas, e.g.
63 /// we treat "\#pragma STDC" and "\#pragma GCC" as namespaces that contain other
64 /// pragmas.
66  std::string Name;
67 
68 public:
69  PragmaHandler() = default;
70  explicit PragmaHandler(StringRef name) : Name(name) {}
71  virtual ~PragmaHandler();
72 
73  StringRef getName() const { return Name; }
74  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
75  Token &FirstToken) = 0;
76 
77  /// getIfNamespace - If this is a namespace, return it. This is equivalent to
78  /// using a dynamic_cast, but doesn't require RTTI.
79  virtual PragmaNamespace *getIfNamespace() { return nullptr; }
80 };
81 
82 /// EmptyPragmaHandler - A pragma handler which takes no action, which can be
83 /// used to ignore particular pragmas.
85 public:
86  explicit EmptyPragmaHandler(StringRef Name = StringRef());
87 
88  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
89  Token &FirstToken) override;
90 };
91 
92 /// PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas,
93 /// allowing hierarchical pragmas to be defined. Common examples of namespaces
94 /// are "\#pragma GCC", "\#pragma STDC", and "\#pragma omp", but any namespaces
95 /// may be (potentially recursively) defined.
97  /// Handlers - This is a map of the handlers in this namespace with their name
98  /// as key.
99  llvm::StringMap<PragmaHandler *> Handlers;
100 
101 public:
102  explicit PragmaNamespace(StringRef Name) : PragmaHandler(Name) {}
103  ~PragmaNamespace() override;
104 
105  /// FindHandler - Check to see if there is already a handler for the
106  /// specified name. If not, return the handler for the null name if it
107  /// exists, otherwise return null. If IgnoreNull is true (the default) then
108  /// the null handler isn't returned on failure to match.
109  PragmaHandler *FindHandler(StringRef Name,
110  bool IgnoreNull = true) const;
111 
112  /// AddPragma - Add a pragma to this namespace.
113  void AddPragma(PragmaHandler *Handler);
114 
115  /// RemovePragmaHandler - Remove the given handler from the
116  /// namespace.
117  void RemovePragmaHandler(PragmaHandler *Handler);
118 
119  bool IsEmpty() const { return Handlers.empty(); }
120 
121  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
122  Token &Tok) override;
123 
124  PragmaNamespace *getIfNamespace() override { return this; }
125 };
126 
127 } // namespace clang
128 
129 #endif // LLVM_CLANG_LEX_PRAGMA_H
The pragma was introduced via the Microsoft __pragma(token-string).
Definition: Pragma.h:47
PragmaIntroducerKind Kind
Definition: Pragma.h:52
RangeSelector name(std::string ID)
Given a node with a "name", (like NamedDecl, DeclRefExpr or CxxCtorInitializer) selects the name&#39;s to...
The pragma was introduced via the C99 _Pragma(string-literal).
Definition: Pragma.h:41
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
const FormatToken & Tok
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
PragmaIntroducerKind
Describes how the pragma was introduced, e.g., with #pragma, _Pragma, or __pragma.
Definition: Pragma.h:32
EmptyPragmaHandler - A pragma handler which takes no action, which can be used to ignore particular p...
Definition: Pragma.h:84
PragmaNamespace * getIfNamespace() override
getIfNamespace - If this is a namespace, return it.
Definition: Pragma.h:124
Encodes a location in the source.
Dataflow Directional Tag Classes.
The pragma was introduced via #pragma.
Definition: Pragma.h:36
virtual PragmaNamespace * getIfNamespace()
getIfNamespace - If this is a namespace, return it.
Definition: Pragma.h:79
PragmaHandler - Instances of this interface defined to handle the various pragmas that the language f...
Definition: Pragma.h:65
PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas, allowing hierarchical pragm...
Definition: Pragma.h:96
bool IsEmpty() const
Definition: Pragma.h:119
PragmaNamespace(StringRef Name)
Definition: Pragma.h:102
Defines the clang::SourceLocation class and associated facilities.
PragmaHandler(StringRef name)
Definition: Pragma.h:70
Describes how and where the pragma was introduced.
Definition: Pragma.h:51
StringRef getName() const
Definition: Pragma.h:73
SourceLocation Loc
Definition: Pragma.h:53
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:125