Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 286 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Support/MemoryBuffer.h b/clang-r353983/include/llvm/Support/MemoryBuffer.h
new file mode 100644
index 00000000..44052697
--- /dev/null
+++ b/clang-r353983/include/llvm/Support/MemoryBuffer.h
@@ -0,0 +1,286 @@
+//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- 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 MemoryBuffer interface.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_MEMORYBUFFER_H
+#define LLVM_SUPPORT_MEMORYBUFFER_H
+
+#include "llvm-c/Types.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/CBindingWrapping.h"
+#include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/FileSystem.h"
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+
+namespace llvm {
+
+class MemoryBufferRef;
+
+/// This interface provides simple read-only access to a block of memory, and
+/// provides simple methods for reading files and standard input into a memory
+/// buffer.  In addition to basic access to the characters in the file, this
+/// interface guarantees you can read one character past the end of the file,
+/// and that this character will read as '\0'.
+///
+/// The '\0' guarantee is needed to support an optimization -- it's intended to
+/// be more efficient for clients which are reading all the data to stop
+/// reading when they encounter a '\0' than to continually check the file
+/// position to see if it has reached the end of the file.
+class MemoryBuffer {
+  const char *BufferStart; // Start of the buffer.
+  const char *BufferEnd;   // End of the buffer.
+
+protected:
+  MemoryBuffer() = default;
+
+  void init(const char *BufStart, const char *BufEnd,
+            bool RequiresNullTerminator);
+
+  static constexpr sys::fs::mapped_file_region::mapmode Mapmode =
+      sys::fs::mapped_file_region::readonly;
+
+public:
+  MemoryBuffer(const MemoryBuffer &) = delete;
+  MemoryBuffer &operator=(const MemoryBuffer &) = delete;
+  virtual ~MemoryBuffer();
+
+  const char *getBufferStart() const { return BufferStart; }
+  const char *getBufferEnd() const   { return BufferEnd; }
+  size_t getBufferSize() const { return BufferEnd-BufferStart; }
+
+  StringRef getBuffer() const {
+    return StringRef(BufferStart, getBufferSize());
+  }
+
+  /// Return an identifier for this buffer, typically the filename it was read
+  /// from.
+  virtual StringRef getBufferIdentifier() const { return "Unknown buffer"; }
+
+  /// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
+  /// if successful, otherwise returning null. If FileSize is specified, this
+  /// means that the client knows that the file exists and that it has the
+  /// specified size.
+  ///
+  /// \param IsVolatile Set to true to indicate that the contents of the file
+  /// can change outside the user's control, e.g. when libclang tries to parse
+  /// while the user is editing/updating the file or if the file is on an NFS.
+  static ErrorOr<std::unique_ptr<MemoryBuffer>>
+  getFile(const Twine &Filename, int64_t FileSize = -1,
+          bool RequiresNullTerminator = true, bool IsVolatile = false);
+
+  /// Read all of the specified file into a MemoryBuffer as a stream
+  /// (i.e. until EOF reached). This is useful for special files that
+  /// look like a regular file but have 0 size (e.g. /proc/cpuinfo on Linux).
+  static ErrorOr<std::unique_ptr<MemoryBuffer>>
+  getFileAsStream(const Twine &Filename);
+
+  /// Given an already-open file descriptor, map some slice of it into a
+  /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
+  /// Since this is in the middle of a file, the buffer is not null terminated.
+  static ErrorOr<std::unique_ptr<MemoryBuffer>>
+  getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize,
+                   int64_t Offset, bool IsVolatile = false);
+
+  /// Given an already-open file descriptor, read the file and return a
+  /// MemoryBuffer.
+  ///
+  /// \param IsVolatile Set to true to indicate that the contents of the file
+  /// can change outside the user's control, e.g. when libclang tries to parse
+  /// while the user is editing/updating the file or if the file is on an NFS.
+  static ErrorOr<std::unique_ptr<MemoryBuffer>>
+  getOpenFile(int FD, const Twine &Filename, uint64_t FileSize,
+              bool RequiresNullTerminator = true, bool IsVolatile = false);
+
+  /// Open the specified memory range as a MemoryBuffer. Note that InputData
+  /// must be null terminated if RequiresNullTerminator is true.
+  static std::unique_ptr<MemoryBuffer>
+  getMemBuffer(StringRef InputData, StringRef BufferName = "",
+               bool RequiresNullTerminator = true);
+
+  static std::unique_ptr<MemoryBuffer>
+  getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true);
+
+  /// Open the specified memory range as a MemoryBuffer, copying the contents
+  /// and taking ownership of it. InputData does not have to be null terminated.
+  static std::unique_ptr<MemoryBuffer>
+  getMemBufferCopy(StringRef InputData, const Twine &BufferName = "");
+
+  /// Read all of stdin into a file buffer, and return it.
+  static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
+
+  /// Open the specified file as a MemoryBuffer, or open stdin if the Filename
+  /// is "-".
+  static ErrorOr<std::unique_ptr<MemoryBuffer>>
+  getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1,
+                 bool RequiresNullTerminator = true);
+
+  /// Map a subrange of the specified file as a MemoryBuffer.
+  static ErrorOr<std::unique_ptr<MemoryBuffer>>
+  getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
+               bool IsVolatile = false);
+
+  //===--------------------------------------------------------------------===//
+  // Provided for performance analysis.
+  //===--------------------------------------------------------------------===//
+
+  /// The kind of memory backing used to support the MemoryBuffer.
+  enum BufferKind {
+    MemoryBuffer_Malloc,
+    MemoryBuffer_MMap
+  };
+
+  /// Return information on the memory mechanism used to support the
+  /// MemoryBuffer.
+  virtual BufferKind getBufferKind() const = 0;
+
+  MemoryBufferRef getMemBufferRef() const;
+};
+
+/// This class is an extension of MemoryBuffer, which allows copy-on-write
+/// access to the underlying contents.  It only supports creation methods that
+/// are guaranteed to produce a writable buffer.  For example, mapping a file
+/// read-only is not supported.
+class WritableMemoryBuffer : public MemoryBuffer {
+protected:
+  WritableMemoryBuffer() = default;
+
+  static constexpr sys::fs::mapped_file_region::mapmode Mapmode =
+      sys::fs::mapped_file_region::priv;
+
+public:
+  using MemoryBuffer::getBuffer;
+  using MemoryBuffer::getBufferEnd;
+  using MemoryBuffer::getBufferStart;
+
+  // const_cast is well-defined here, because the underlying buffer is
+  // guaranteed to have been initialized with a mutable buffer.
+  char *getBufferStart() {
+    return const_cast<char *>(MemoryBuffer::getBufferStart());
+  }
+  char *getBufferEnd() {
+    return const_cast<char *>(MemoryBuffer::getBufferEnd());
+  }
+  MutableArrayRef<char> getBuffer() {
+    return {getBufferStart(), getBufferEnd()};
+  }
+
+  static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
+  getFile(const Twine &Filename, int64_t FileSize = -1,
+          bool IsVolatile = false);
+
+  /// Map a subrange of the specified file as a WritableMemoryBuffer.
+  static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
+  getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
+               bool IsVolatile = false);
+
+  /// Allocate a new MemoryBuffer of the specified size that is not initialized.
+  /// Note that the caller should initialize the memory allocated by this
+  /// method. The memory is owned by the MemoryBuffer object.
+  static std::unique_ptr<WritableMemoryBuffer>
+  getNewUninitMemBuffer(size_t Size, const Twine &BufferName = "");
+
+  /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note
+  /// that the caller need not initialize the memory allocated by this method.
+  /// The memory is owned by the MemoryBuffer object.
+  static std::unique_ptr<WritableMemoryBuffer>
+  getNewMemBuffer(size_t Size, const Twine &BufferName = "");
+
+private:
+  // Hide these base class factory function so one can't write
+  //   WritableMemoryBuffer::getXXX()
+  // and be surprised that he got a read-only Buffer.
+  using MemoryBuffer::getFileAsStream;
+  using MemoryBuffer::getFileOrSTDIN;
+  using MemoryBuffer::getMemBuffer;
+  using MemoryBuffer::getMemBufferCopy;
+  using MemoryBuffer::getOpenFile;
+  using MemoryBuffer::getOpenFileSlice;
+  using MemoryBuffer::getSTDIN;
+};
+
+/// This class is an extension of MemoryBuffer, which allows write access to
+/// the underlying contents and committing those changes to the original source.
+/// It only supports creation methods that are guaranteed to produce a writable
+/// buffer.  For example, mapping a file read-only is not supported.
+class WriteThroughMemoryBuffer : public MemoryBuffer {
+protected:
+  WriteThroughMemoryBuffer() = default;
+
+  static constexpr sys::fs::mapped_file_region::mapmode Mapmode =
+      sys::fs::mapped_file_region::readwrite;
+
+public:
+  using MemoryBuffer::getBuffer;
+  using MemoryBuffer::getBufferEnd;
+  using MemoryBuffer::getBufferStart;
+
+  // const_cast is well-defined here, because the underlying buffer is
+  // guaranteed to have been initialized with a mutable buffer.
+  char *getBufferStart() {
+    return const_cast<char *>(MemoryBuffer::getBufferStart());
+  }
+  char *getBufferEnd() {
+    return const_cast<char *>(MemoryBuffer::getBufferEnd());
+  }
+  MutableArrayRef<char> getBuffer() {
+    return {getBufferStart(), getBufferEnd()};
+  }
+
+  static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>>
+  getFile(const Twine &Filename, int64_t FileSize = -1);
+
+  /// Map a subrange of the specified file as a ReadWriteMemoryBuffer.
+  static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>>
+  getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset);
+
+private:
+  // Hide these base class factory function so one can't write
+  //   WritableMemoryBuffer::getXXX()
+  // and be surprised that he got a read-only Buffer.
+  using MemoryBuffer::getFileAsStream;
+  using MemoryBuffer::getFileOrSTDIN;
+  using MemoryBuffer::getMemBuffer;
+  using MemoryBuffer::getMemBufferCopy;
+  using MemoryBuffer::getOpenFile;
+  using MemoryBuffer::getOpenFileSlice;
+  using MemoryBuffer::getSTDIN;
+};
+
+class MemoryBufferRef {
+  StringRef Buffer;
+  StringRef Identifier;
+
+public:
+  MemoryBufferRef() = default;
+  MemoryBufferRef(MemoryBuffer& Buffer)
+      : Buffer(Buffer.getBuffer()), Identifier(Buffer.getBufferIdentifier()) {}
+  MemoryBufferRef(StringRef Buffer, StringRef Identifier)
+      : Buffer(Buffer), Identifier(Identifier) {}
+
+  StringRef getBuffer() const { return Buffer; }
+
+  StringRef getBufferIdentifier() const { return Identifier; }
+
+  const char *getBufferStart() const { return Buffer.begin(); }
+  const char *getBufferEnd() const { return Buffer.end(); }
+  size_t getBufferSize() const { return Buffer.size(); }
+};
+
+// Create wrappers for C Binding types (see CBindingWrapping.h).
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_MEMORYBUFFER_H