Frontend: Simplify handling of non-seeking streams in CompilerInstance, NFC

Add a new `raw_pwrite_ostream` variant, `buffer_unique_ostream`, which
is like `buffer_ostream` but with unique ownership of the stream it's
wrapping. Use this in CompilerInstance to simplify the ownership of
non-seeking output streams, avoiding logic sprawled around to deal with
them specially.

This also simplifies future work to encapsulate output files in a
different class.

Differential Revision: https://reviews.llvm.org/D93260

1 files changed, 1 insertions, 5 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index f694f41..d60a0e8 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -678,7 +678,6 @@ void CompilerInstance::clearOutputFiles(bool EraseFiles) {
       llvm::sys::fs::remove(Module.second);
     BuiltModules.clear();
   }
-  NonSeekStream.reset();
 }
 
 std::unique_ptr<raw_pwrite_stream>
@@ -816,10 +815,7 @@ std::unique_ptr<llvm::raw_pwrite_stream> CompilerInstance::createOutputFile(
   if (!Binary || OS->supportsSeeking())
     return std::move(OS);
 
-  auto B = std::make_unique<llvm::buffer_ostream>(*OS);
-  assert(!NonSeekStream);
-  NonSeekStream = std::move(OS);
-  return std::move(B);
+  return std::make_unique<llvm::buffer_unique_ostream>(std::move(OS));
 }
 
 // Initialization Utilities