[llvm-objcopy] Factor out Buffer

In this diff we move out the hierarchy of buffers from Object.h/Object.cpp 
into separate files since it is not ELF-specific and will be reused later. 
After this change Object.h/Object.cpp are almost exclusively ELF-specific.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D53298

llvm-svn: 344585

llvm/tools/llvm-objcopy/Buffer.cpp

@@ -0,0 +1,51 @@
+//===- Buffer.cpp ---------------------------------------------------------===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Buffer.h"
+#include "llvm-objcopy.h"
+#include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <memory>
+
+namespace llvm {
+namespace objcopy {
+
+Buffer::~Buffer() {}
+
+void FileBuffer::allocate(size_t Size) {
+  Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
+      FileOutputBuffer::create(getName(), Size, FileOutputBuffer::F_executable);
+  handleAllErrors(BufferOrErr.takeError(), [this](const ErrorInfoBase &E) {
+    error("failed to open " + getName() + ": " + E.message());
+  });
+  Buf = std::move(*BufferOrErr);
+}
+
+Error FileBuffer::commit() { return Buf->commit(); }
+
+uint8_t *FileBuffer::getBufferStart() {
+  return reinterpret_cast<uint8_t *>(Buf->getBufferStart());
+}
+
+void MemBuffer::allocate(size_t Size) {
+  Buf = WritableMemoryBuffer::getNewMemBuffer(Size, getName());
+}
+
+Error MemBuffer::commit() { return Error::success(); }
+
+uint8_t *MemBuffer::getBufferStart() {
+  return reinterpret_cast<uint8_t *>(Buf->getBufferStart());
+}
+
+std::unique_ptr<WritableMemoryBuffer> MemBuffer::releaseMemoryBuffer() {
+  return std::move(Buf);
+}
+
+} // end namespace objcopy
+} // end namespace llvm

llvm/tools/llvm-objcopy/Buffer.h

@@ -0,0 +1,66 @@
+//===- Buffer.h -------------------------------------------------*- C++ -*-===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_OBJCOPY_BUFFER_H
+#define LLVM_TOOLS_OBJCOPY_BUFFER_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <memory>
+
+namespace llvm {
+namespace objcopy {
+
+// The class Buffer abstracts out the common interface of FileOutputBuffer and
+// WritableMemoryBuffer so that the hierarchy of Writers depends on this
+// abstract interface and doesn't depend on a particular implementation.
+// TODO: refactor the buffer classes in LLVM to enable us to use them here
+// directly.
+class Buffer {
+  StringRef Name;
+
+public:
+  virtual ~Buffer();
+  virtual void allocate(size_t Size) = 0;
+  virtual uint8_t *getBufferStart() = 0;
+  virtual Error commit() = 0;
+
+  explicit Buffer(StringRef Name) : Name(Name) {}
+  StringRef getName() const { return Name; }
+};
+
+class FileBuffer : public Buffer {
+  std::unique_ptr<FileOutputBuffer> Buf;
+
+public:
+  void allocate(size_t Size) override;
+  uint8_t *getBufferStart() override;
+  Error commit() override;
+
+  explicit FileBuffer(StringRef FileName) : Buffer(FileName) {}
+};
+
+class MemBuffer : public Buffer {
+  std::unique_ptr<WritableMemoryBuffer> Buf;
+
+public:
+  void allocate(size_t Size) override;
+  uint8_t *getBufferStart() override;
+  Error commit() override;
+
+  explicit MemBuffer(StringRef Name) : Buffer(Name) {}
+
+  std::unique_ptr<WritableMemoryBuffer> releaseMemoryBuffer();
+};
+
+} // end namespace objcopy
+} // end namespace llvm
+
+#endif // LLVM_TOOLS_OBJCOPY_BUFFER_H

llvm/tools/llvm-objcopy/CMakeLists.txt

@@ -14,6 +14,7 @@ tablegen(LLVM StripOpts.inc -gen-opt-parser-defs)
 add_public_tablegen_target(StripOptsTableGen)
 
 add_llvm_tool(llvm-objcopy
+  Buffer.cpp
   CopyConfig.cpp
   llvm-objcopy.cpp
   Object.cpp

llvm/tools/llvm-objcopy/Object.cpp

@@ -33,37 +33,6 @@ using namespace llvm::objcopy;
 using namespace object;
 using namespace ELF;
 
-Buffer::~Buffer() {}
-
-void FileBuffer::allocate(size_t Size) {
-  Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
-      FileOutputBuffer::create(getName(), Size, FileOutputBuffer::F_executable);
-  handleAllErrors(BufferOrErr.takeError(), [this](const ErrorInfoBase &E) {
-    error("failed to open " + getName() + ": " + E.message());
-  });
-  Buf = std::move(*BufferOrErr);
-}
-
-Error FileBuffer::commit() { return Buf->commit(); }
-
-uint8_t *FileBuffer::getBufferStart() {
-  return reinterpret_cast<uint8_t *>(Buf->getBufferStart());
-}
-
-void MemBuffer::allocate(size_t Size) {
-  Buf = WritableMemoryBuffer::getNewMemBuffer(Size, getName());
-}
-
-Error MemBuffer::commit() { return Error::success(); }
-
-uint8_t *MemBuffer::getBufferStart() {
-  return reinterpret_cast<uint8_t *>(Buf->getBufferStart());
-}
-
-std::unique_ptr<WritableMemoryBuffer> MemBuffer::releaseMemoryBuffer() {
-  return std::move(Buf);
-}
-
 template <class ELFT> void ELFWriter<ELFT>::writePhdr(const Segment &Seg) {
   uint8_t *B = Buf.getBufferStart();
   B += Obj.ProgramHdrSegment.Offset + Seg.Index * sizeof(Elf_Phdr);

llvm/tools/llvm-objcopy/Object.h

@@ -10,6 +10,7 @@
 #ifndef LLVM_TOOLS_OBJCOPY_OBJECT_H
 #define LLVM_TOOLS_OBJCOPY_OBJECT_H
 
+#include "Buffer.h"
 #include "CopyConfig.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
@@ -30,7 +31,6 @@ namespace llvm {
 enum class DebugCompressionType;
 namespace objcopy {
 
-class Buffer;
 class SectionBase;
 class Section;
 class OwnedDataSection;
@@ -146,48 +146,6 @@ public:
   explicit BinarySectionWriter(Buffer &Buf) : SectionWriter(Buf) {}
 };
 
-// The class Buffer abstracts out the common interface of FileOutputBuffer and
-// WritableMemoryBuffer so that the hierarchy of Writers depends on this
-// abstract interface and doesn't depend on a particular implementation.
-// TODO: refactor the buffer classes in LLVM to enable us to use them here
-// directly.
-class Buffer {
-  StringRef Name;
-
-public:
-  virtual ~Buffer();
-  virtual void allocate(size_t Size) = 0;
-  virtual uint8_t *getBufferStart() = 0;
-  virtual Error commit() = 0;
-
-  explicit Buffer(StringRef Name) : Name(Name) {}
-  StringRef getName() const { return Name; }
-};
-
-class FileBuffer : public Buffer {
-  std::unique_ptr<FileOutputBuffer> Buf;
-
-public:
-  void allocate(size_t Size) override;
-  uint8_t *getBufferStart() override;
-  Error commit() override;
-
-  explicit FileBuffer(StringRef FileName) : Buffer(FileName) {}
-};
-
-class MemBuffer : public Buffer {
-  std::unique_ptr<WritableMemoryBuffer> Buf;
-
-public:
-  void allocate(size_t Size) override;
-  uint8_t *getBufferStart() override;
-  Error commit() override;
-
-  explicit MemBuffer(StringRef Name) : Buffer(Name) {}
-
-  std::unique_ptr<WritableMemoryBuffer> releaseMemoryBuffer();
-};
-
 class Writer {
 protected:
   Object &Obj;

llvm/tools/llvm-objcopy/llvm-objcopy.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm-objcopy.h"
+#include "Buffer.h"
 #include "CopyConfig.h"
 #include "Object.h"