Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===--- HeaderMap.h - A file that acts like dir of symlinks ----*- C++ -*-===//

//

// 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 the HeaderMap interface.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LEX_HEADERMAP_H

#define LLVM_CLANG_LEX_HEADERMAP_H

#include "clang/Basic/FileManager.h"

#include "clang/Basic/LLVM.h"

#include "clang/Lex/HeaderMapTypes.h"

#include "llvm/ADT/StringMap.h"

#include "llvm/Support/Compiler.h"

#include "llvm/Support/MemoryBuffer.h"

#include <memory>

#include <optional>

namespace clang {

struct HMapBucket;

struct HMapHeader;

/// Implementation for \a HeaderMap that doesn't depend on \a FileManager.

class HeaderMapImpl {

  std::unique_ptr<const llvm::MemoryBuffer> FileBuffer;

  bool NeedsBSwap;

  mutable llvm::StringMap<StringRef> ReverseMap;

public:

  HeaderMapImpl(std::unique_ptr<const llvm::MemoryBuffer> File, bool NeedsBSwap)

      : FileBuffer(std::move(File)), NeedsBSwap(NeedsBSwap) {}

  // Check for a valid header and extract the byte swap.

  static bool checkHeader(const llvm::MemoryBuffer &File, bool &NeedsByteSwap);

  // Make a call for every Key in the map.

  template <typename Func> void forEachKey(Func Callback) const {

    const HMapHeader &Hdr = getHeader();

    unsigned NumBuckets = getEndianAdjustedWord(Hdr.NumBuckets);

    for (unsigned Bucket = 0; Bucket < NumBuckets; ++Bucket) {

      HMapBucket B = getBucket(Bucket);

      if (B.Key != HMAP_EmptyBucketKey)

        if (std::optional<StringRef> Key = getString(B.Key))

          Callback(*Key);

    }

  }

  /// If the specified relative filename is located in this HeaderMap return

  /// the filename it is mapped to, otherwise return an empty StringRef.

  StringRef lookupFilename(StringRef Filename,

                           SmallVectorImpl<char> &DestPath) const;

  /// Return the filename of the headermap.

  StringRef getFileName() const;

  /// Print the contents of this headermap to stderr.

  void dump() const;

  /// Return key for specifed path.

  StringRef reverseLookupFilename(StringRef DestPath) const;

private:

  unsigned getEndianAdjustedWord(unsigned X) const;

  const HMapHeader &getHeader() const;

  HMapBucket getBucket(unsigned BucketNo) const;

  /// Look up the specified string in the string table.  If the string index is

  /// not valid, return std::nullopt.

  std::optional<StringRef> getString(unsigned StrTabIdx) const;

};

/// This class represents an Apple concept known as a 'header map'.  To the

/// \#include file resolution process, it basically acts like a directory of

/// symlinks to files.  Its advantages are that it is dense and more efficient

/// to create and process than a directory of symlinks.

class HeaderMap : private HeaderMapImpl {

  HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File, bool BSwap)

      : HeaderMapImpl(std::move(File), BSwap) {}

public:

  /// This attempts to load the specified file as a header map.  If it doesn't

  /// look like a HeaderMap, it gives up and returns null.

  static std::unique_ptr<HeaderMap> Create(const FileEntry *FE,

                                           FileManager &FM);

  using HeaderMapImpl::dump;

  using HeaderMapImpl::forEachKey;

  using HeaderMapImpl::getFileName;

  using HeaderMapImpl::lookupFilename;

  using HeaderMapImpl::reverseLookupFilename;

};

} // end namespace clang.

#endif