RFR: 8317611: Add a tool like jdeprscan to find usage of restricted methods [v9]

[Alan Bateman]

On Mon, 24 Jun 2024 12:57:39 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:
> 
>   de-dupe on path, not module name

src/jdk.jdeps/share/classes/com/sun/tools/jnativescan/JNativeScanTask.java line 105:

> 103:                     for (String classPathEntry : classPathAttribute) {
> 104:                         Path otherJar = parentDir != null
> 105:                                 ? parentDir.resolve(classPathEntry)

We'lll need to create a follow on issue to re-examine this as the value of a Class-Path attribute aren't sequence of relative URIs (with an optional "file" URI scheme) rather than file paths. Treating it as a file path may work in some cases but won't work once you encounter cases that use escaping.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19774#discussion_r1659018308