[llvm] r322094 - [Support] Add WritableMemoryBuffer::getNewMemBuffer

[Pavel Labath via llvm-commits]

Author: labath
Date: Tue Jan  9 09:26:06 2018
New Revision: 322094

URL: http://llvm.org/viewvc/llvm-project?rev=322094&view=rev
Log:
[Support] Add WritableMemoryBuffer::getNewMemBuffer

Summary:
The idea is that it would replace
(non-Writable)MemoryBuffer::getNewMemBuffer, which is quite useless
unless you const_cast its contents to write to it (which all (both)
callers of this function were doing). This patch also fixes one of the usages in
COFFWriter. After fixing the other usage in clang, I plan to delete the old
function.

Reviewers: dblaikie, Bigcheese

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41540

Modified:
    llvm/trunk/include/llvm/Support/MemoryBuffer.h
    llvm/trunk/lib/Object/WindowsResource.cpp
    llvm/trunk/lib/Support/MemoryBuffer.cpp
    llvm/trunk/unittests/Support/MemoryBufferTest.cpp

Modified: llvm/trunk/include/llvm/Support/MemoryBuffer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/MemoryBuffer.h?rev=322094&r1=322093&r2=322094&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/MemoryBuffer.h (original)
+++ llvm/trunk/include/llvm/Support/MemoryBuffer.h Tue Jan  9 09:26:06 2018
@@ -117,9 +117,8 @@ public:
   static std::unique_ptr<MemoryBuffer>
   getMemBufferCopy(StringRef InputData, 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.
+  // TODO: Remove after all callers are switched to
+  // WritableMemoryBuffer::getNewMemBuffer
   static std::unique_ptr<MemoryBuffer>
   getNewMemBuffer(size_t Size, StringRef BufferName = "");
 
@@ -196,6 +195,12 @@ public:
   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()
@@ -204,7 +209,6 @@ private:
   using MemoryBuffer::getFileOrSTDIN;
   using MemoryBuffer::getMemBuffer;
   using MemoryBuffer::getMemBufferCopy;
-  using MemoryBuffer::getNewMemBuffer;
   using MemoryBuffer::getOpenFile;
   using MemoryBuffer::getOpenFileSlice;
   using MemoryBuffer::getSTDIN;

Modified: llvm/trunk/lib/Object/WindowsResource.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/WindowsResource.cpp?rev=322094&r1=322093&r2=322094&view=diff
==============================================================================
--- llvm/trunk/lib/Object/WindowsResource.cpp (original)
+++ llvm/trunk/lib/Object/WindowsResource.cpp Tue Jan  9 09:26:06 2018
@@ -334,7 +334,7 @@ private:
   void writeDirectoryTree();
   void writeDirectoryStringTable();
   void writeFirstSectionRelocations();
-  std::unique_ptr<MemoryBuffer> OutputBuffer;
+  std::unique_ptr<WritableMemoryBuffer> OutputBuffer;
   char *BufferStart;
   uint64_t CurrentOffset = 0;
   COFF::MachineTypes MachineType;
@@ -360,7 +360,7 @@ WindowsResourceCOFFWriter::WindowsResour
       Data(Parser.getData()), StringTable(Parser.getStringTable()) {
   performFileLayout();
 
-  OutputBuffer = MemoryBuffer::getNewMemBuffer(FileSize);
+  OutputBuffer = WritableMemoryBuffer::getNewMemBuffer(FileSize);
 }
 
 void WindowsResourceCOFFWriter::performFileLayout() {
@@ -425,7 +425,7 @@ static std::time_t getTime() {
 }
 
 std::unique_ptr<MemoryBuffer> WindowsResourceCOFFWriter::write() {
-  BufferStart = const_cast<char *>(OutputBuffer->getBufferStart());
+  BufferStart = OutputBuffer->getBufferStart();
 
   writeCOFFHeader();
   writeFirstSectionHeader();

Modified: llvm/trunk/lib/Support/MemoryBuffer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/MemoryBuffer.cpp?rev=322094&r1=322093&r2=322094&view=diff
==============================================================================
--- llvm/trunk/lib/Support/MemoryBuffer.cpp (original)
+++ llvm/trunk/lib/Support/MemoryBuffer.cpp Tue Jan  9 09:26:06 2018
@@ -141,11 +141,7 @@ MemoryBuffer::getMemBufferCopy(StringRef
 
 std::unique_ptr<MemoryBuffer>
 MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
-  auto SB = WritableMemoryBuffer::getNewUninitMemBuffer(Size, BufferName);
-  if (!SB)
-    return nullptr;
-  memset(SB->getBufferStart(), 0, Size);
-  return std::move(SB);
+  return WritableMemoryBuffer::getNewMemBuffer(Size, BufferName);
 }
 
 ErrorOr<std::unique_ptr<MemoryBuffer>>
@@ -306,6 +302,15 @@ WritableMemoryBuffer::getNewUninitMemBuf
   return std::unique_ptr<WritableMemoryBuffer>(Ret);
 }
 
+std::unique_ptr<WritableMemoryBuffer>
+WritableMemoryBuffer::getNewMemBuffer(size_t Size, const Twine &BufferName) {
+  auto SB = WritableMemoryBuffer::getNewUninitMemBuffer(Size, BufferName);
+  if (!SB)
+    return nullptr;
+  memset(SB->getBufferStart(), 0, Size);
+  return SB;
+}
+
 static bool shouldUseMmap(int FD,
                           size_t FileSize,
                           size_t MapSize,

Modified: llvm/trunk/unittests/Support/MemoryBufferTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/MemoryBufferTest.cpp?rev=322094&r1=322093&r2=322094&view=diff
==============================================================================
--- llvm/trunk/unittests/Support/MemoryBufferTest.cpp (original)
+++ llvm/trunk/unittests/Support/MemoryBufferTest.cpp Tue Jan  9 09:26:06 2018
@@ -116,13 +116,13 @@ TEST_F(MemoryBufferTest, make_new) {
   EXPECT_TRUE(nullptr != Two.get());
 
   // 0-initialized buffer with no name
-  OwningBuffer Three(MemoryBuffer::getNewMemBuffer(321, data));
+  OwningBuffer Three(WritableMemoryBuffer::getNewMemBuffer(321, data));
   EXPECT_TRUE(nullptr != Three.get());
   for (size_t i = 0; i < 321; ++i)
     EXPECT_EQ(0, Three->getBufferStart()[0]);
 
   // 0-initialized buffer with name
-  OwningBuffer Four(MemoryBuffer::getNewMemBuffer(123, "zeros"));
+  OwningBuffer Four(WritableMemoryBuffer::getNewMemBuffer(123, "zeros"));
   EXPECT_TRUE(nullptr != Four.get());
   for (size_t i = 0; i < 123; ++i)
     EXPECT_EQ(0, Four->getBufferStart()[0]);