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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"
17#include "clang/Basic/SourceLocation.h"
18#include "llvm/ADT/StringMap.h"
19#include "llvm/ADT/StringRef.h"
20#include <string>
21
22namespace clang {
23
24class PragmaNamespace;
25class Preprocessor;
26class Token;
27
28 /**
29 * Describes how the pragma was introduced, e.g., with \#pragma,
30 * _Pragma, or __pragma.
31 */
32 enum PragmaIntroducerKind {
33 /**
34 * The pragma was introduced via \#pragma.
35 */
36 PIK_HashPragma,
37
38 /**
39 * The pragma was introduced via the C99 _Pragma(string-literal).
40 */
41 PIK__Pragma,
42
43 /**
44 * The pragma was introduced via the Microsoft
45 * __pragma(token-string).
46 */
47 PIK___pragma
48 };
49
50 /// Describes how and where the pragma was introduced.
51 struct PragmaIntroducer {
52 PragmaIntroducerKind Kind;
53 SourceLocation Loc;
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.
65class PragmaHandler {
66 std::string Name;
67
68public:
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.
84class EmptyPragmaHandler : public PragmaHandler {
85public:
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.
96class PragmaNamespace : public PragmaHandler {
97 /// Handlers - This is a map of the handlers in this namespace with their name
98 /// as key.
99 llvm::StringMap<std::unique_ptr<PragmaHandler>> Handlers;
100
101public:
102 explicit PragmaNamespace(StringRef Name) : PragmaHandler(Name) {}
103
104 /// FindHandler - Check to see if there is already a handler for the
105 /// specified name. If not, return the handler for the null name if it
106 /// exists, otherwise return null. If IgnoreNull is true (the default) then
107 /// the null handler isn't returned on failure to match.
108 PragmaHandler *FindHandler(StringRef Name,
109 bool IgnoreNull = true) const;
110
111 /// AddPragma - Add a pragma to this namespace.
112 void AddPragma(PragmaHandler *Handler);
113
114 /// RemovePragmaHandler - Remove the given handler from the
115 /// namespace.
116 void RemovePragmaHandler(PragmaHandler *Handler);
117
118 bool IsEmpty() const { return Handlers.empty(); }
119
120 void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
121 Token &Tok) override;
122
123 PragmaNamespace *getIfNamespace() override { return this; }
124};
125
126} // namespace clang
127
128#endif // LLVM_CLANG_LEX_PRAGMA_H
129

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source code of clang/include/clang/Lex/Pragma.h