CodeGenHelpers.h

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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines common utilities for generating C++ code.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_TABLEGEN_CODEGENHELPERS_H
#define LLVM_TABLEGEN_CODEGENHELPERS_H
 
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/raw_ostream.h"
#include <string>
 
namespace llvm {
// Simple RAII helper for emitting ifdef-undef-endif scope.
class IfDefEmitter {
public:
  IfDefEmitter(raw_ostream &OS, StringRef Name) : Name(Name.str()), OS(OS) {
    OS << "#ifdef " << Name << "\n"
       << "#undef " << Name << "\n\n";
  }
  ~IfDefEmitter() { OS << "\n#endif // " << Name << "\n\n"; }
 
private:
  std::string Name;
  raw_ostream &OS;
};
 
// Simple RAII helper for emitting namespace scope. Name can be a single
// namespace (empty for anonymous namespace) or nested namespace.
class NamespaceEmitter {
public:
  NamespaceEmitter(raw_ostream &OS, StringRef Name) : OS(OS) {
    emitNamespaceStarts(Name);
  }
 
  ~NamespaceEmitter() { close(); }
 
  // Explicit function to close the namespace scopes.
  void close() {
    for (StringRef NS : llvm::reverse(Namespaces))
      OS << "} // namespace " << NS << "\n";
    Namespaces.clear();
  }
 
private:
  void emitNamespaceStarts(StringRef Name) {
    llvm::SplitString(Name, Namespaces, "::");
    for (StringRef NS : Namespaces)
      OS << "namespace " << NS << " {\n";
  }
 
  SmallVector<StringRef, 2> Namespaces;
  raw_ostream &OS;
};
 
} // end namespace llvm
 
#endif // LLVM_TABLEGEN_CODEGENHELPERS_H