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, 7 insertions, 9 deletions

diff --git a/llvm/lib/Object/SymbolicFile.cpp b/llvm/lib/Object/SymbolicFile.cpp
index 790d5a75ba7..f8dd4b33a39 100644
--- a/llvm/lib/Object/SymbolicFile.cpp
+++ b/llvm/lib/Object/SymbolicFile.cpp
@@ -19,23 +19,21 @@
 using namespace llvm;
 using namespace object;
 
-SymbolicFile::SymbolicFile(unsigned int Type,
-                           std::unique_ptr<MemoryBuffer> Source)
-    : Binary(Type, std::move(Source)) {}
+SymbolicFile::SymbolicFile(unsigned int Type, MemoryBufferRef Source)
+    : Binary(Type, Source) {}
 
 SymbolicFile::~SymbolicFile() {}
 
-ErrorOr<std::unique_ptr<SymbolicFile>>
-SymbolicFile::createSymbolicFile(std::unique_ptr<MemoryBuffer> &Object,
-                                 sys::fs::file_magic Type,
-                                 LLVMContext *Context) {
+ErrorOr<std::unique_ptr<SymbolicFile>> SymbolicFile::createSymbolicFile(
+    MemoryBufferRef Object, sys::fs::file_magic Type, LLVMContext *Context) {
+  StringRef Data = Object.getBuffer();
   if (Type == sys::fs::file_magic::unknown)
-    Type = sys::fs::identify_magic(Object->getBuffer());
+    Type = sys::fs::identify_magic(Data);
 
   switch (Type) {
   case sys::fs::file_magic::bitcode:
     if (Context)
-      return IRObjectFile::createIRObjectFile(std::move(Object), *Context);
+      return IRObjectFile::createIRObjectFile(Object, *Context);
   // Fallthrough
   case sys::fs::file_magic::unknown:
   case sys::fs::file_magic::archive: