clang  6.0.0svn
Pragma.h
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1 //===--- Pragma.h - Pragma registration and handling ------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the PragmaHandler and PragmaTable interfaces.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LEX_PRAGMA_H
15 #define LLVM_CLANG_LEX_PRAGMA_H
16 
17 #include "clang/Basic/LLVM.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/ADT/StringRef.h"
20 #include <cassert>
21 
22 namespace clang {
23  class Preprocessor;
24  class Token;
25  class IdentifierInfo;
26  class PragmaNamespace;
27 
28  /**
29  * \brief Describes how the pragma was introduced, e.g., with \#pragma,
30  * _Pragma, or __pragma.
31  */
33  /**
34  * \brief The pragma was introduced via \#pragma.
35  */
37 
38  /**
39  * \brief The pragma was introduced via the C99 _Pragma(string-literal).
40  */
42 
43  /**
44  * \brief The pragma was introduced via the Microsoft
45  * __pragma(token-string).
46  */
48  };
49 
50 /// PragmaHandler - Instances of this interface defined to handle the various
51 /// pragmas that the language front-end uses. Each handler optionally has a
52 /// name (e.g. "pack") and the HandlePragma method is invoked when a pragma with
53 /// that identifier is found. If a handler does not match any of the declared
54 /// pragmas the handler with a null identifier is invoked, if it exists.
55 ///
56 /// Note that the PragmaNamespace class can be used to subdivide pragmas, e.g.
57 /// we treat "\#pragma STDC" and "\#pragma GCC" as namespaces that contain other
58 /// pragmas.
60  std::string Name;
61 public:
62  explicit PragmaHandler(StringRef name) : Name(name) {}
64  virtual ~PragmaHandler();
65 
66  StringRef getName() const { return Name; }
67  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
68  Token &FirstToken) = 0;
69 
70  /// getIfNamespace - If this is a namespace, return it. This is equivalent to
71  /// using a dynamic_cast, but doesn't require RTTI.
72  virtual PragmaNamespace *getIfNamespace() { return nullptr; }
73 };
74 
75 /// EmptyPragmaHandler - A pragma handler which takes no action, which can be
76 /// used to ignore particular pragmas.
78 public:
79  explicit EmptyPragmaHandler(StringRef Name = StringRef());
80 
81  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
82  Token &FirstToken) override;
83 };
84 
85 /// PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas,
86 /// allowing hierarchical pragmas to be defined. Common examples of namespaces
87 /// are "\#pragma GCC", "\#pragma STDC", and "\#pragma omp", but any namespaces
88 /// may be (potentially recursively) defined.
90  /// Handlers - This is a map of the handlers in this namespace with their name
91  /// as key.
92  ///
93  llvm::StringMap<PragmaHandler*> Handlers;
94 public:
95  explicit PragmaNamespace(StringRef Name) : PragmaHandler(Name) {}
96  ~PragmaNamespace() override;
97 
98  /// FindHandler - Check to see if there is already a handler for the
99  /// specified name. If not, return the handler for the null name if it
100  /// exists, otherwise return null. If IgnoreNull is true (the default) then
101  /// the null handler isn't returned on failure to match.
102  PragmaHandler *FindHandler(StringRef Name,
103  bool IgnoreNull = true) const;
104 
105  /// AddPragma - Add a pragma to this namespace.
106  ///
107  void AddPragma(PragmaHandler *Handler);
108 
109  /// RemovePragmaHandler - Remove the given handler from the
110  /// namespace.
111  void RemovePragmaHandler(PragmaHandler *Handler);
112 
113  bool IsEmpty() {
114  return Handlers.empty();
115  }
116 
117  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
118  Token &FirstToken) override;
119 
120  PragmaNamespace *getIfNamespace() override { return this; }
121 };
122 
123 
124 } // end namespace clang
125 
126 #endif
virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer, Token &FirstToken)=0
The pragma was introduced via the Microsoft __pragma(token-string).
Definition: Pragma.h:47
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:35
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:77
PragmaNamespace * getIfNamespace() override
getIfNamespace - If this is a namespace, return it.
Definition: Pragma.h:120
virtual ~PragmaHandler()
Definition: Pragma.cpp:50
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:72
PragmaHandler - Instances of this interface defined to handle the various pragmas that the language f...
Definition: Pragma.h:59
PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas, allowing hierarchical pragm...
Definition: Pragma.h:89
PragmaNamespace(StringRef Name)
Definition: Pragma.h:95
PragmaHandler(StringRef name)
Definition: Pragma.h:62
StringRef getName() const
Definition: Pragma.h:66
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:98