[flang-commits] [flang] [flang][docs] Add an FAQ about an executable stack (PR #171241)

[Yusuke MINATO via flang-commits]

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@@ -0,0 +1,53 @@
+<!--===- docs/FAQ.md
+
+   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
+
+-->
+
+<!-- TODO: remove this after adding this page to ToC -->
+```{eval-rst}
+:orphan:
+```
+
+# Frequently Asked Questions (FAQ)
+
+```{contents}
+---
+local:
+---
+```
+
+## Driver
+
+### Why do I get a warning or error about an executable stack?
+
+This occurs because Flang's implementation of pointers to internal procedures requires an executable stack.
+
+When an internal procedure is referenced from outside its host scope (e.g., via a procedure pointer), the implementation must ensure that it can still access its host-associated variables.
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yus3710-fj wrote:

I agree that "parent" is clearer, but the standard calls it "host". In fact, the standard uses the word "parent" in the context of inheritance for derived types. Maybe we should distinguish between them.

https://github.com/llvm/llvm-project/pull/171241