1 //===- Pragma.h - Pragma registration and handling --------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the PragmaHandler and PragmaTable interfaces.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LEX_PRAGMA_H
15 #define LLVM_CLANG_LEX_PRAGMA_H
17 #include "clang/Basic/LLVM.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/ADT/StringRef.h"
24 class PragmaNamespace;
29 * Describes how the pragma was introduced, e.g., with \#pragma,
30 * _Pragma, or __pragma.
32 enum PragmaIntroducerKind {
34 * The pragma was introduced via \#pragma.
39 * The pragma was introduced via the C99 _Pragma(string-literal).
44 * The pragma was introduced via the Microsoft
45 * __pragma(token-string).
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.
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
63 PragmaHandler() = default;
64 explicit PragmaHandler(StringRef name) : Name(name) {}
65 virtual ~PragmaHandler();
67 StringRef getName() const { return Name; }
68 virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
69 Token &FirstToken) = 0;
71 /// getIfNamespace - If this is a namespace, return it. This is equivalent to
72 /// using a dynamic_cast, but doesn't require RTTI.
73 virtual PragmaNamespace *getIfNamespace() { return nullptr; }
76 /// EmptyPragmaHandler - A pragma handler which takes no action, which can be
77 /// used to ignore particular pragmas.
78 class EmptyPragmaHandler : public PragmaHandler {
80 explicit EmptyPragmaHandler(StringRef Name = StringRef());
82 void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
83 Token &FirstToken) override;
86 /// PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas,
87 /// allowing hierarchical pragmas to be defined. Common examples of namespaces
88 /// are "\#pragma GCC", "\#pragma STDC", and "\#pragma omp", but any namespaces
89 /// may be (potentially recursively) defined.
90 class PragmaNamespace : public PragmaHandler {
91 /// Handlers - This is a map of the handlers in this namespace with their name
93 llvm::StringMap<PragmaHandler *> Handlers;
96 explicit PragmaNamespace(StringRef Name) : PragmaHandler(Name) {}
97 ~PragmaNamespace() override;
99 /// FindHandler - Check to see if there is already a handler for the
100 /// specified name. If not, return the handler for the null name if it
101 /// exists, otherwise return null. If IgnoreNull is true (the default) then
102 /// the null handler isn't returned on failure to match.
103 PragmaHandler *FindHandler(StringRef Name,
104 bool IgnoreNull = true) const;
106 /// AddPragma - Add a pragma to this namespace.
107 void AddPragma(PragmaHandler *Handler);
109 /// RemovePragmaHandler - Remove the given handler from the
111 void RemovePragmaHandler(PragmaHandler *Handler);
113 bool IsEmpty() const { return Handlers.empty(); }
115 void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
116 Token &Tok) override;
118 PragmaNamespace *getIfNamespace() override { return this; }
123 #endif // LLVM_CLANG_LEX_PRAGMA_H