Reapply "Make BitCodeAbbrev ownership explicit using shared_ptr rather than IntrusiveRefCntPtr""

If this is a problem for anyone (shared_ptr is two pointers in size,
whereas IntrusiveRefCntPtr is 1 - and the ref count control block that
make_shared adds is probably larger than the one int in RefCountedBase)
I'd prefer to address this by adding a lower-overhead version of
shared_ptr (possibly refactoring IntrusiveRefCntPtr into such a thing)
to avoid the intrusiveness - this allows memory ownership to remain
orthogonal to types and at least to me, seems to make code easier to
understand (since no implicit ownership acquisition can happen).

This recommits 291006, reverted in r291007.

llvm-svn: 291016

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitstreamReader.cpp b/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
index 43c9aebd79e..0c45b4b4cde 100644
--- a/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
@@ -273,7 +273,7 @@ unsigned BitstreamCursor::readRecord(unsigned AbbrevID,
 }
 
 void BitstreamCursor::ReadAbbrevRecord() {
-  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
+  auto Abbv = std::make_shared<BitCodeAbbrev>();
   unsigned NumOpInfo = ReadVBR(5);
   for (unsigned i = 0; i != NumOpInfo; ++i) {
     bool IsLiteral = Read(1);
@@ -307,7 +307,7 @@ void BitstreamCursor::ReadAbbrevRecord() {
 
   if (Abbv->getNumOperandInfos() == 0)
     report_fatal_error("Abbrev record with no operands");
-  CurAbbrevs.push_back(Abbv);
+  CurAbbrevs.push_back(std::move(Abbv));
 }
 
 Optional<BitstreamBlockInfo>