Switch raw_svector_ostream to use the vector as the ostream buffer.

 - This avoids unnecessary malloc/free overhead in the common case, and
   unnecessary copying from the ostream buffer into the output vector.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79434 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 0 deletions

diff --git a/include/llvm/Support/raw_ostream.h b/include/llvm/Support/raw_ostream.h
index 1668cc5..ed06dbf 100644
--- a/include/llvm/Support/raw_ostream.h
+++ b/include/llvm/Support/raw_ostream.h
@@ -452,6 +452,10 @@ class raw_svector_ostream : public raw_ostream {
   /// counting the bytes currently in the buffer.
   virtual uint64_t current_pos();
 public:
+  /// Construct a new raw_svector_ostream.
+  ///
+  /// \arg O - The vector to write to; this *must* have at least 128 bytes of
+  /// free space in it.
   explicit raw_svector_ostream(SmallVectorImpl<char> &O);
   ~raw_svector_ostream();
 };