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, 13 insertions, 22 deletions

diff --git a/llvm/lib/Object/ELFObjectFile.cpp b/llvm/lib/Object/ELFObjectFile.cpp
index 2e5e3c8836c..8ccb2538ac7 100644
--- a/llvm/lib/Object/ELFObjectFile.cpp
+++ b/llvm/lib/Object/ELFObjectFile.cpp
@@ -17,65 +17,56 @@
 namespace llvm {
 using namespace object;
 
-ELFObjectFileBase::ELFObjectFileBase(unsigned int Type,
-                                     std::unique_ptr<MemoryBuffer> Source)
-    : ObjectFile(Type, std::move(Source)) {}
+ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source)
+    : ObjectFile(Type, Source) {}
 
 ErrorOr<std::unique_ptr<ObjectFile>>
-ObjectFile::createELFObjectFile(std::unique_ptr<MemoryBuffer> &Obj) {
+ObjectFile::createELFObjectFile(MemoryBufferRef Obj) {
   std::pair<unsigned char, unsigned char> Ident =
-      getElfArchType(Obj->getBuffer());
+      getElfArchType(Obj.getBuffer());
   std::size_t MaxAlignment =
-    1ULL << countTrailingZeros(uintptr_t(Obj->getBufferStart()));
+      1ULL << countTrailingZeros(uintptr_t(Obj.getBufferStart()));
 
   std::error_code EC;
   std::unique_ptr<ObjectFile> R;
   if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
     if (MaxAlignment >= 4)
-      R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(
-          std::move(Obj), EC));
+      R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(Obj, EC));
     else
 #endif
     if (MaxAlignment >= 2)
-      R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(
-          std::move(Obj), EC));
+      R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(Obj, EC));
     else
       return object_error::parse_failed;
   else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
     if (MaxAlignment >= 4)
-      R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(std::move(Obj),
-                                                                 EC));
+      R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(Obj, EC));
     else
 #endif
     if (MaxAlignment >= 2)
-      R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(std::move(Obj),
-                                                                 EC));
+      R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(Obj, EC));
     else
       return object_error::parse_failed;
   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
     if (MaxAlignment >= 8)
-      R.reset(new ELFObjectFile<ELFType<support::big, 8, true>>(std::move(Obj),
-                                                                EC));
+      R.reset(new ELFObjectFile<ELFType<support::big, 8, true>>(Obj, EC));
     else
 #endif
     if (MaxAlignment >= 2)
-      R.reset(new ELFObjectFile<ELFType<support::big, 2, true>>(std::move(Obj),
-                                                                EC));
+      R.reset(new ELFObjectFile<ELFType<support::big, 2, true>>(Obj, EC));
     else
       return object_error::parse_failed;
   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
     if (MaxAlignment >= 8)
-      R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(
-          std::move(Obj), EC));
+      R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(Obj, EC));
     else
 #endif
     if (MaxAlignment >= 2)
-      R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(
-          std::move(Obj), EC));
+      R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(Obj, EC));
     else
       return object_error::parse_failed;
   }