RFR: 8268829: Provide an optimized way to walk the stack with Class object only [v11]

[Mandy Chung]

> 8268829: Provide an optimized way to walk the stack with Class object only
> 
> `StackWalker::walk` creates one `StackFrame` per frame and the current implementation
> allocates one `StackFrameInfo` and one `MemberName` objects per frame. Some frameworks
> like logging may only interest in the Class object but not the method name nor the BCI,
> for example, filters out its implementation classes to find the caller class.  It's
> similar to `StackWalker::getCallerClass` but allows a predicate to filter out the element.
> 
> This PR proposes to add `Option::DROP_METHOD_INFO` enum that requests to drop the method information.  If no method information is needed, a `StackWalker` with `DROP_METHOD_INFO`
> can be used instead and such stack walker will save the overhead of extracting the method information
> and the memory used for the stack walking.
> 
> New factory methods to take a parameter to specify the kind of stack walker to be created are defined.
> This provides a simple way for existing code, for example logging frameworks, to take advantage of
> this enhancement with the least change as it can keep the existing function for traversing
> `StackFrame`s.
> 
> For example: to find the first caller filtering a known list of implementation class,
> existing code can create a stack walker instance with `DROP_METHOD_INFO` option:
> 
> 
>      StackWalker walker = StackWalker.getInstance(Option.DROP_METHOD_INFO, Option.RETAIN_CLASS_REFERENCE);
>      Optional<Class<?>> callerClass = walker.walk(s ->
>              s.map(StackFrame::getDeclaringClass)
>               .filter(Predicate.not(implClasses::contains))
>               .findFirst());
> 
> 
> If method information is accessed on the `StackFrame`s produced by this stack walker such as
> `StackFrame::getMethodName`, then `UnsupportedOperationException` will be thrown.
> 
> #### Javadoc & specdiff
> 
> https://cr.openjdk.org/~mchung/api/java.base/java/lang/StackWalker.html
> https://cr.openjdk.org/~mchung/jdk22/specdiff/overview-summary.html
> 
> #### Alternatives Considered
> One alternative is to provide a new API:
> `<T> T walkClass(Function<? super Stream<Class<?>, ? extends T> function)`
> 
> In this case, the caller would need to pass a function that takes a stream
> of `Class` object instead of `StackFrame`.  Existing code would have to
> modify calls to the `walk` method to `walkClass` and the function body.
> 
> ### Implementation Details
> 
> A `StackWalker` configured with `DROP_METHOD_INFO` option creates `ClassFrameInfo[]`
> buffer that is filled by the VM during stack walking.   `Sta...

Mandy Chung has updated the pull request incrementally with one additional commit since the last revision:

  review feedback

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/15370/files
  - new: https://git.openjdk.org/jdk/pull/15370/files/a623b9dc..0e6abc42

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15370&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15370&range=09-10

  Stats: 22 lines in 3 files changed: 21 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/15370.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15370/head:pull/15370

PR: https://git.openjdk.org/jdk/pull/15370