8307572: AArch64: Vector registers are clobbered by some macroassemblers

[nsjian]

I found that MacroAssembler::arrays_equals() would call stubcode, which may use vector registers. However, the call site in match rule does not claim the use of vector registers. Since c2 will allocate v16-v31 first [1], it's rare that using of v0-v7 will cause problem, but I did create a test case to expose the bug.

Apart from arrays_equals, I also checked other macroassemblers, and found several similar issues. Fixed by claiming those vector register being killed in match rules call sites, which should have minimal performance impact compared to always saving/restoring those vector registers, since those V0-Vx registers are rarely allocated and live cross the macroassembler call.

A jtreg test case is also added to demonstrate the failure. Test will fail without this patch, and pass with this patch.

Test: I tried to update the allocation order in [1] to allocate V0-V15 first and then V16-V31, and full jtreg tests passed with the allocation order changed. (I did found some test failures with this allocation order change without this patch). I have also eyeballed and checked other macroassembler calls, and others seemed fine.

[1] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/aarch64/aarch64.ad#L424

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Issue

• JDK-8307572: AArch64: Vector registers are clobbered by some macroassemblers

Reviewers

• Andrew Haley (@theRealAph - Reviewer)
• Andrew Dinn (@adinn - Reviewer)

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[theRealAph]

Great catch, thanks. Does this one need backports?

[openjdk]

@nsjian This change now passes all automated pre-integration checks.

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8307572: AArch64: Vector registers are clobbered by some macroassemblers

Reviewed-by: aph, adinn

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At the time when this comment was updated there had been 74 new commits pushed to the master branch:

• 0cbfbc4: 8307813: [JVMCI] Export markWord::lock_mask_in_place to JVMCI compilers.
• ba9714d: 8307610: Linker::nativeLinker should not be restricted (mainline)
• ecc1d85: 8307869: Remove unnecessary log statements from arm32 fastlocking code
• 08fa269: 8307349: Support xlc17 clang toolchain on AIX
• 8ac7186: 8305416: runtime/Thread/TestAlwaysPreTouchStacks.java failed with "Did not find expected NMT output"
• 984fbbb: 8307810: Consistently use LockingMode instead of UseHeavyMonitors
• 39f4e4d: 8307758: RISC-V: Improve bit test code introduced by JDK-8291555
• 3cb606e: 8306965: osThread allocation failures should not abort the VM
• 4795c39: 8281103: Give example for Locale that is English and follows the ISO standards
• 958d4a7: 8307563: make most fields final in JavacTrees
• ... and 64 more: https://git.openjdk.org/jdk/compare/ad0e5a99ca1ad9dd04105f502985735a3536c3f4...master

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[nsjian]

Great catch, thanks. Does this one need backports?

I think so. I will handle the backports as well.

[adinn]

Nice work Ningsheng!

[nsjian]

Thanks for the review! @theRealAph @adinn

[nsjian]

/integrate

[openjdk]

Going to push as commit 33d9a85.
Since your change was applied there have been 89 commits pushed to the master branch:

• 9a7b443: 8307966: ProblemList java/util/concurrent/locks/Lock/OOMEInAQS.java on linux-x64
• 54c06d2: 8307559: Add better checking in com/sun/jdi tests for debuggee exiting unexpectedly with an exception
• ce59077: 8307945: Build of Client VM is broken after JDK-8307058
• a667213: 8281715: Move "base CDS archive not loaded" tests to SharedArchiveFileOption.java
• 29b8242: 8307954: Update string template regression tests to be robust on release updates
• 4f355c3: 8307653: Adjust delay time and gc log argument in TestAbortOnVMOperationTimeout
• 1535863: 8307848: update for deprecated sprintf for jdk.attach
• cbecf42: 8307850: update for deprecated sprintf for jdk.jdi
• 7fcb0fd: 8307139: Fix signed integer overflow in compiler code, part 1
• 5d6cce0: 8307298: JFR: Ensure jdk.jfr.internal.TypeLibrary is initialized only once
• ... and 79 more: https://git.openjdk.org/jdk/compare/ad0e5a99ca1ad9dd04105f502985735a3536c3f4...master

Your commit was automatically rebased without conflicts.

[openjdk]

@nsjian Pushed as commit 33d9a85.

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