[MC] Use unique_ptr to manage WinFrameInfos, NFC

The FrameInfo cannot be stored directly in the vector because chained
frames may refer to parent frames, so we need pointers that are stable
across a vector resize.

llvm-svn: 315080
diff --git a/llvm/lib/MC/MCWin64EH.cpp b/llvm/lib/MC/MCWin64EH.cpp
index fdc4c10..44dd8f1 100644
--- a/llvm/lib/MC/MCWin64EH.cpp
+++ b/llvm/lib/MC/MCWin64EH.cpp
@@ -220,17 +220,17 @@
 
 void llvm::Win64EH::UnwindEmitter::Emit(MCStreamer &Streamer) const {
   // Emit the unwind info structs first.
-  for (WinEH::FrameInfo *CFI : Streamer.getWinFrameInfos()) {
+  for (const auto &CFI : Streamer.getWinFrameInfos()) {
     MCSection *XData = Streamer.getAssociatedXDataSection(CFI->TextSection);
     Streamer.SwitchSection(XData);
-    ::EmitUnwindInfo(Streamer, CFI);
+    ::EmitUnwindInfo(Streamer, CFI.get());
   }
 
   // Now emit RUNTIME_FUNCTION entries.
-  for (WinEH::FrameInfo *CFI : Streamer.getWinFrameInfos()) {
+  for (const auto &CFI : Streamer.getWinFrameInfos()) {
     MCSection *PData = Streamer.getAssociatedPDataSection(CFI->TextSection);
     Streamer.SwitchSection(PData);
-    EmitRuntimeFunction(Streamer, CFI);
+    EmitRuntimeFunction(Streamer, CFI.get());
   }
 }