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, 9 insertions, 10 deletions

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index 5bcb4bae8ea..746fd7391bc 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -222,10 +222,9 @@ static uint32_t getSectionFlags(const MachOObjectFile *O,
   return Sect.flags;
 }
 
-MachOObjectFile::MachOObjectFile(std::unique_ptr<MemoryBuffer> Object,
-                                 bool IsLittleEndian, bool Is64bits,
-                                 std::error_code &EC)
-    : ObjectFile(getMachOType(IsLittleEndian, Is64bits), std::move(Object)),
+MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
+                                 bool Is64bits, std::error_code &EC)
+    : ObjectFile(getMachOType(IsLittleEndian, Is64bits), Object),
       SymtabLoadCmd(nullptr), DysymtabLoadCmd(nullptr),
       DataInCodeLoadCmd(nullptr) {
   uint32_t LoadCommandCount = this->getHeader().ncmds;
@@ -1776,18 +1775,18 @@ bool MachOObjectFile::isRelocatableObject() const {
 }
 
 ErrorOr<std::unique_ptr<MachOObjectFile>>
-ObjectFile::createMachOObjectFile(std::unique_ptr<MemoryBuffer> &Buffer) {
-  StringRef Magic = Buffer->getBuffer().slice(0, 4);
+ObjectFile::createMachOObjectFile(MemoryBufferRef Buffer) {
+  StringRef Magic = Buffer.getBuffer().slice(0, 4);
   std::error_code EC;
   std::unique_ptr<MachOObjectFile> Ret;
   if (Magic == "\xFE\xED\xFA\xCE")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), false, false, EC));
+    Ret.reset(new MachOObjectFile(Buffer, false, false, EC));
   else if (Magic == "\xCE\xFA\xED\xFE")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), true, false, EC));
+    Ret.reset(new MachOObjectFile(Buffer, true, false, EC));
   else if (Magic == "\xFE\xED\xFA\xCF")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), false, true, EC));
+    Ret.reset(new MachOObjectFile(Buffer, false, true, EC));
   else if (Magic == "\xCF\xFA\xED\xFE")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), true, true, EC));
+    Ret.reset(new MachOObjectFile(Buffer, true, true, EC));
   else
     return object_error::parse_failed;