[NFC] [Coroutines] Use llvm::make_scope_exit to replace self-defined RTTIHelper

Author: ChuanqiXu9

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -16,6 +16,7 @@
 
 #include "CoroInternal.h"
 #include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Analysis/PtrUseVisitor.h"
 #include "llvm/Analysis/StackLifetime.h"
@@ -576,13 +577,8 @@ void FrameTypeBuilder::addFieldForAllocas(const Function &F,
   using AllocaSetType = SmallVector<AllocaInst *, 4>;
   SmallVector<AllocaSetType, 4> NonOverlapedAllocas;
 
-  // We need to add field for allocas at the end of this function. However, this
-  // function has multiple exits, so we use this helper to avoid redundant code.
-  struct RTTIHelper {
-    std::function<void()> func;
-    RTTIHelper(std::function<void()> &&func) : func(func) {}
-    ~RTTIHelper() { func(); }
-  } Helper([&]() {
+  // We need to add field for allocas at the end of this function.
+  auto AddFieldForAllocasAtExit = make_scope_exit([&]() {
     for (auto AllocaList : NonOverlapedAllocas) {
       auto *LargestAI = *AllocaList.begin();
       FieldIDType Id = addFieldForAlloca(LargestAI);