Unwind checksum and digest intrinsics on ARM64 #1400
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apangin
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| @Test(mainClass = CodingIntrinsics.class, debugNonSafepoints = true, arch = {Arch.ARM64, Arch.X64}, inputs = "") | ||
| @Test(mainClass = CodingIntrinsics.class, debugNonSafepoints = true, arch = {Arch.ARM64, Arch.X64}, inputs = "--cstack vm", nameSuffix = "VM") | ||
| public void intrinsics(TestProcess p) throws Exception { |
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@apangin I've observed that this test could be quite fragile on Systems where we don't have dwarf support
This can be observed on macOS in our GHA
I would recommend disabling this test for macOS until we have proper dwarf support in it, what do you think?
Example => https://github.com/async-profiler/async-profiler/actions/runs/16412814698/job/46371796767
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Thanks for pointing this out. The problem has nothing to do with dwarf support, but it's likely that the test reveals an actual gap in the profiler's stack walking algorithm. I'll take a look.
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Description
Unwind certain ARM64 intrinsics.
Related issues
#1385
Motivation and context
HotSpot JVM has hand-coded assembly implementation for some CPU intensive checksum and digest computation algorithms suchs as CRC32, MD5, SHA256, etc. These compiler intrinsic functions are generated at runtime and they do not follow commonly used frame layout, especially on ARM64. That's why async-profiler (as well as JDK Flight Recorder and other profilers) cannot unwind Java stack trace during execution of these functions.
I divided stub routines for these intrinsics into 4 categories:
x30register.stpinstruction that decrement stack pointer by this fixed amount. To unwind these stubs, I find frame size directly from the instruction stream and incrementspback by this amount.fp(x29) register to find the previous frame.spin the middle). These cases are rare, and I do not attempt to unwind such frames.How has this been tested?
Added new test
CodingIntrinsics.javathat executes the following intrinsics:By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.