Don't own the buffer in object::Binary.

Owning the buffer is somewhat inflexible. Some Binaries have sub Binaries
(like Archive) and we had to create dummy buffers just to handle that. It is
also a bad fit for IRObjectFile where the Module wants to own the buffer too.

Keeping this ownership would make supporting IR inside native objects
particularly painful.

This patch focuses in lib/Object. If something elsewhere used to own an Binary,
now it also owns a MemoryBuffer.

This patch introduces a few new types.

* MemoryBufferRef. This is just a pair of StringRefs for the data and name.
  This is to MemoryBuffer as StringRef is to std::string.
* OwningBinary. A combination of Binary and a MemoryBuffer. This is needed
  for convenience functions that take a filename and return both the
  buffer and the Binary using that buffer.

The C api now uses OwningBinary to avoid any change in semantics. I will start
a new thread to see if we want to change it and how.

llvm-svn: 216002

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/DebugInfo/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARFUnit.cpp
index d528216..6ed3e04 100644
--- a/llvm/lib/DebugInfo/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARFUnit.cpp
@@ -261,12 +261,12 @@ bool DWARFUnit::parseDWO() {
     sys::path::append(AbsolutePath, CompilationDir);
   }
   sys::path::append(AbsolutePath, DWOFileName);
-  ErrorOr<std::unique_ptr<object::ObjectFile>> DWOFile =
+  ErrorOr<object::OwningBinary<object::ObjectFile>> DWOFile =
       object::ObjectFile::createObjectFile(AbsolutePath);
   if (!DWOFile)
     return false;
   // Reset DWOHolder.
-  DWO = llvm::make_unique<DWOHolder>(std::move(*DWOFile));
+  DWO = llvm::make_unique<DWOHolder>(std::move(DWOFile->getBinary()));
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.
   if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {