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//===- Pragma.h - Pragma registration and handling --------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines the PragmaHandler and PragmaTable interfaces.
#include "clang/Basic/LLVM.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include <string>
namespace clang {
class PragmaNamespace;
class Preprocessor;
class Token;
* Describes how the pragma was introduced, e.g., with \#pragma,
* _Pragma, or __pragma.
enum PragmaIntroducerKind {
* The pragma was introduced via \#pragma.
* The pragma was introduced via the C99 _Pragma(string-literal).
* The pragma was introduced via the Microsoft
* __pragma(token-string).
/// Describes how and where the pragma was introduced.
struct PragmaIntroducer {
PragmaIntroducerKind Kind;
SourceLocation Loc;
/// PragmaHandler - Instances of this interface defined to handle the various
/// pragmas that the language front-end uses. Each handler optionally has a
/// name (e.g. "pack") and the HandlePragma method is invoked when a pragma with
/// that identifier is found. If a handler does not match any of the declared
/// pragmas the handler with a null identifier is invoked, if it exists.
/// Note that the PragmaNamespace class can be used to subdivide pragmas, e.g.
/// we treat "\#pragma STDC" and "\#pragma GCC" as namespaces that contain other
/// pragmas.
class PragmaHandler {
std::string Name;
PragmaHandler() = default;
explicit PragmaHandler(StringRef name) : Name(name) {}
virtual ~PragmaHandler();
StringRef getName() const { return Name; }
virtual void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
Token &FirstToken) = 0;
/// getIfNamespace - If this is a namespace, return it. This is equivalent to
/// using a dynamic_cast, but doesn't require RTTI.
virtual PragmaNamespace *getIfNamespace() { return nullptr; }
/// EmptyPragmaHandler - A pragma handler which takes no action, which can be
/// used to ignore particular pragmas.
class EmptyPragmaHandler : public PragmaHandler {
explicit EmptyPragmaHandler(StringRef Name = StringRef());
void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
Token &FirstToken) override;
/// PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas,
/// allowing hierarchical pragmas to be defined. Common examples of namespaces
/// are "\#pragma GCC", "\#pragma STDC", and "\#pragma omp", but any namespaces
/// may be (potentially recursively) defined.
class PragmaNamespace : public PragmaHandler {
/// Handlers - This is a map of the handlers in this namespace with their name
/// as key.
llvm::StringMap<PragmaHandler *> Handlers;
explicit PragmaNamespace(StringRef Name) : PragmaHandler(Name) {}
~PragmaNamespace() override;
/// FindHandler - Check to see if there is already a handler for the
/// specified name. If not, return the handler for the null name if it
/// exists, otherwise return null. If IgnoreNull is true (the default) then
/// the null handler isn't returned on failure to match.
PragmaHandler *FindHandler(StringRef Name,
bool IgnoreNull = true) const;
/// AddPragma - Add a pragma to this namespace.
void AddPragma(PragmaHandler *Handler);
/// RemovePragmaHandler - Remove the given handler from the
/// namespace.
void RemovePragmaHandler(PragmaHandler *Handler);
bool IsEmpty() const { return Handlers.empty(); }
void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
Token &Tok) override;
PragmaNamespace *getIfNamespace() override { return this; }
} // namespace clang