RFR: 8338596: Clarify handling of restricted and caller-sensitive methods [v8]

[Alan Bateman]

On Wed, 9 Oct 2024 11:24:43 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> This PR moves the section on restricted methods from the the javadoc of `java.lang.foreign` package into a standalone static [javadoc page](https://cr.openjdk.org/~mcimadamore/jdk/restricted_javadoc_section/docs/api/java.base/java/lang/foreign/doc-files/RestrictedMethods.html).
>> 
>> This is because, after [JEP 472](https://openjdk.org/jeps/472), we now have restricted methods *outside* the foreign package, namely `System::loadLibrary`, `Runtime::loadLibrary` (and related methods). And, even before, we also had a restricted method in `ModuleLayer.Controller`.
>> 
>> The new static page contains some guidance of what happens when a restricted method is called when there's no Java frame on the stack (this can happen e.g. when upcalling into a restricted method from a native thread not known to the JVM) - that is, the call is treated as originating from an unnamed module.
>> 
>> The static page is linked from the restricted method banner in a restricted method javadoc. Here's an [example](https://cr.openjdk.org/~mcimadamore/jdk/restricted_javadoc_section/docs/api/java.base/java/lang/foreign/Linker.html#downcallHandle(java.lang.foreign.MemorySegment,java.lang.foreign.FunctionDescriptor,java.lang.foreign.Linker.Option...)).
>
> Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains nine additional commits since the last revision:
> 
>  - Merge branch 'master' into restricted_better_javadoc
>  - Merge pull request #22 from hns/restricted_better_javadoc
>    
>    Only link restricted method doc-file if it is available
>  - Only link restricted method doc-file if it is available
>  - Fix paths to links
>  - Fix javadoc test failure
>  - Revert reference to caller stack
>  - Update src/java.base/share/classes/java/lang/doc-files/RestrictedMethods.html
>    
>    Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
>  - Move restricted method page to `java.lang`
>    Update restricted method page
>  - Initial push

Marked as reviewed by alanb (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/21067#pullrequestreview-2368250090