RFR: 8269592: [JVMCI] Optimize c2v_iterateFrames

[Andreas Woess]

On Thu, 8 Jul 2021 18:26:34 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> I have concern about relaxing guarantees in `asJavaVFrame()`. It is shared code and the only case when we can see native frame is call from JVMCI's method `iterateFrames()` as I understand. Then relaxation should be JVMCI specific.

@vnkozlov The changes to `asJavaVFrame()` seemed like a good idea since `vframeStream` iterates all javaVFrames including native frames but, without these changes, fails the `_frame.is_compiled_frame()` guarantee for native frames. This is ok if you filter the frames by method first, as is the case with current usages, but you won't be able to use `asJavaVFrame()` on all vframes in the stream.
If the change is considered problematic/too risky, we can work around it.

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PR: https://git.openjdk.java.net/jdk/pull/4625