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, 8 insertions, 5 deletions

diff --git a/llvm/lib/ProfileData/CoverageMappingReader.cpp b/llvm/lib/ProfileData/CoverageMappingReader.cpp
index c8108d4ce99..965e085f9d9 100644
--- a/llvm/lib/ProfileData/CoverageMappingReader.cpp
+++ b/llvm/lib/ProfileData/CoverageMappingReader.cpp
@@ -292,11 +292,13 @@ ObjectFileCoverageMappingReader::ObjectFileCoverageMappingReader(
 ObjectFileCoverageMappingReader::ObjectFileCoverageMappingReader(
     std::unique_ptr<MemoryBuffer> &ObjectBuffer, sys::fs::file_magic Type)
     : CurrentRecord(0) {
-  auto File = llvm::object::ObjectFile::createObjectFile(ObjectBuffer, Type);
+  auto File = object::ObjectFile::createObjectFile(
+      ObjectBuffer->getMemBufferRef(), Type);
   if (!File)
     error(File.getError());
   else
-    Object = std::move(File.get());
+    Object = OwningBinary<ObjectFile>(std::move(File.get()),
+                                      std::move(ObjectBuffer));
 }
 
 namespace {
@@ -429,16 +431,17 @@ std::error_code readCoverageMappingData(
 }
 
 std::error_code ObjectFileCoverageMappingReader::readHeader() {
-  if (!Object)
+  ObjectFile *OF = Object.getBinary().get();
+  if (!OF)
     return getError();
-  auto BytesInAddress = Object->getBytesInAddress();
+  auto BytesInAddress = OF->getBytesInAddress();
   if (BytesInAddress != 4 && BytesInAddress != 8)
     return error(instrprof_error::malformed);
 
   // Look for the sections that we are interested in.
   int FoundSectionCount = 0;
   SectionRef ProfileNames, CoverageMapping;
-  for (const auto &Section : Object->sections()) {
+  for (const auto &Section : OF->sections()) {
     StringRef Name;
     if (auto Err = Section.getName(Name))
       return Err;