[llvm] Minimal unwinding information (DWARF CFI) checker (PR #145633)

[Simon Tatham via llvm-commits]

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@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file declares CFIFunctionFrameAnalyzer class.
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statham-arm wrote:

This class appears to be a derived class of the no-op base class `CFIFunctionFrameReceiver`, which overrides the methods to actually do something. An explanation here should say that, and say what it does.

In particular, after this class receives CFI instructions and thinks about them, what happens as a consequence? There don't seem to be any query methods that allow you to get information back out of it.

(Having read the rest of your code, I know the answer – the answer is that you use the provided `MCContext` to emit warnings and errors. But _say so_ in a comment here, so that it isn't necessary to go and read the main source file to figure out what's going on.)

https://github.com/llvm/llvm-project/pull/145633