[clang] [CIR] Add support for normal cleanups (PR #149948)

[Henrich Lauko via cfe-commits]

================
@@ -0,0 +1,71 @@
+//===--- CIRGenCleanup.cpp - Bookkeeping and code emission for cleanups ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains code dealing with the IR generation for cleanups
+// and related information.
+//
+// A "cleanup" is a piece of code which needs to be executed whenever
+// control transfers out of a particular scope.  This can be
+// conditionalized to occur only on exceptional control flow, only on
+// normal control flow, or both.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CIRGenFunction.h"
+
+#include "clang/CIR/MissingFeatures.h"
+
+using namespace clang;
+using namespace clang::CIRGen;
+using namespace cir;
+
+//===----------------------------------------------------------------------===//
+// CIRGenFunction cleanup related
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// EHScopeStack
+//===----------------------------------------------------------------------===//
+
+void EHScopeStack::Cleanup::anchor() {}
+
+static mlir::Block *getCurCleanupBlock(CIRGenFunction &cgf) {
+  mlir::OpBuilder::InsertionGuard guard(cgf.getBuilder());
+  mlir::Block *cleanup =
+      cgf.curLexScope->getOrCreateCleanupBlock(cgf.getBuilder());
+  return cleanup;
+}
+
+/// Pops a cleanup block. If the block includes a normal cleanup, the
+/// current insertion point is threaded through the cleanup, as are
+/// any branch fixups on the cleanup.
+void CIRGenFunction::popCleanupBlock() {
+  assert(!ehStack.cleanupStack.empty() && "cleanup stack is empty!");
+  mlir::OpBuilder::InsertionGuard guard(builder);
+  EHScopeStack::Cleanup *cleanup = ehStack.cleanupStack.pop_back_val();
----------------
xlauko wrote:

what about unique pointer here and remove the explicit delete later?

e.g.:

```cpp
    auto cleanup = std::unique_ptr<EHScopeStack::Cleanup>(ehStack.cleanupStack.pop_back_val());
```


https://github.com/llvm/llvm-project/pull/149948