1 //===- Pragma.h - Pragma registration and handling --------------*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
9 // This file defines the PragmaHandler and PragmaTable interfaces.
11 //===----------------------------------------------------------------------===//
13 #ifndef LLVM_CLANG_LEX_PRAGMA_H
14 #define LLVM_CLANG_LEX_PRAGMA_H
16 #include "clang/Basic/LLVM.h"
17 #include "clang/Basic/SourceLocation.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 /// Describes how and where the pragma was introduced.
51 struct PragmaIntroducer {
52 PragmaIntroducerKind Kind;
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.
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
69 PragmaHandler() = default;
70 explicit PragmaHandler(StringRef name) : Name(name) {}
71 virtual ~PragmaHandler();
73 StringRef getName() const { return Name; }
74 virtual void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
75 Token &FirstToken) = 0;
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; }
82 /// EmptyPragmaHandler - A pragma handler which takes no action, which can be
83 /// used to ignore particular pragmas.
84 class EmptyPragmaHandler : public PragmaHandler {
86 explicit EmptyPragmaHandler(StringRef Name = StringRef());
88 void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
89 Token &FirstToken) override;
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.
96 class PragmaNamespace : public PragmaHandler {
97 /// Handlers - This is a map of the handlers in this namespace with their name
99 llvm::StringMap<std::unique_ptr<PragmaHandler>> Handlers;
102 explicit PragmaNamespace(StringRef Name) : PragmaHandler(Name) {}
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;
111 /// AddPragma - Add a pragma to this namespace.
112 void AddPragma(PragmaHandler *Handler);
114 /// RemovePragmaHandler - Remove the given handler from the
116 void RemovePragmaHandler(PragmaHandler *Handler);
118 bool IsEmpty() const { return Handlers.empty(); }
120 void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
121 Token &Tok) override;
123 PragmaNamespace *getIfNamespace() override { return this; }
126 /// Destringize a \c _Pragma("") string according to C11 6.10.9.1:
127 /// "The string literal is destringized by deleting any encoding prefix,
128 /// deleting the leading and trailing double-quotes, replacing each escape
129 /// sequence \" by a double-quote, and replacing each escape sequence \\ by a
130 /// single backslash."
131 void prepare_PragmaString(SmallVectorImpl<char> &StrVal);
135 #endif // LLVM_CLANG_LEX_PRAGMA_H