RFR: 8317611: Add a tool like jdeprscan to find usage of restricted methods [v5]

[Alan Bateman]

On Thu, 20 Jun 2024 12:11:25 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> This PR adds a new JDK tool, called `jnativescan`, that can be used to find code that accesses native functionality. Currently this includes `native` method declarations, and methods marked with `@Restricted`.
>> 
>> The tool accepts a list of class path and module path entries through `--class-path` and `--module-path`, and a set of root modules through `--add-modules`, as well as an optional target release with `--release`.
>> 
>> The default mode is for the tool to report all uses of `@Restricted` methods, and `native` method declaration in a tree-like structure:
>> 
>> 
>> app.jar (ALL-UNNAMED):
>>   main.Main:
>>     main.Main::main(String[])void references restricted methods:
>>       java.lang.foreign.MemorySegment::reinterpret(long)MemorySegment
>>     main.Main::m()void is a native method declaration
>> 
>> 
>> The `--print-native-access` option can be used print out all the module names of modules doing native access in a comma separated list. For class path code, this will print out `ALL-UNNAMED`.
>> 
>> Testing: 
>> - `langtools_jnativescan` tests.
>> - Running the tool over jextract's libclang bindings, which use the FFM API, and thus has a lot of references to `@Restricted` methods.
>> - tier 1-3
>
> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
> 
>   update man page header to be consisten with the others

One thing to check is usages like `jnativescan foo`, should that fail as the tool doesn't take args.

Another thing is that using joptsimple gives up a bit of control, e.g. the help output shows the parameter for --class-path as `<String>` where the java launcher and other tools will show "path" or "class path".  Same thing with `--release` where it shows  `<String>` where jar, javac, and other tools will say "release".   Not important for now, just comments from trying out the tool.

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PR Comment: https://git.openjdk.org/jdk/pull/19774#issuecomment-2181070909