8330153: C2: dump barrier information for all Mach nodes

[robcasloz]

This debug-only changeset ensures that GC-specific barrier information is dumped (via BarrierSetC2::dump_barrier_data()) for all C2 Mach nodes, not just MachType ones. This makes it possible to e.g. write IR tests that verify barrier properties of CompareAndSwap/WeakCompareAndSwap Mach implementations, which do not inherit from MachTypeNode. An example of such a test can be found here.

The following program illustrates the effect of the change:

import java.lang.invoke.VarHandle;
import java.lang.invoke.MethodHandles;

public class Example {
    static class Outer {
        Object f;
    }

    static final VarHandle fVarHandle;
    static {
        MethodHandles.Lookup l = MethodHandles.lookup();
        try {
            fVarHandle = l.findVarHandle(Outer.class, "f", Object.class);
        } catch (Exception e) {
            throw new Error(e);
        }
    }

    static boolean testCompareAndSwap(Outer o, Object oldVal, Object newVal) {
        return fVarHandle.compareAndSet(o, oldVal, newVal);
    }

    public static void main(String[] args) {
        for (int i = 0; i < 10_000; i++) {
            Outer o = new Outer();
            Object oldVal = new Object();
            o.f = oldVal;
            Object newVal = new Object();
            testCompareAndSwap(o, oldVal, newVal);
        }
    }
}

Before this changeset, issuing this command:

$ java -Xbatch -XX:+UseZGC -XX:+ZGenerational -XX:CompileOnly=Example::testCompareAndSwap -XX:CompileCommand=PrintIdealPhase,Example::testCompareAndSwap,FINAL_CODE Example.java | grep zCompareAndSwapP

gives the following dump:

 R10     37  zCompareAndSwapP  === 28 35 38 54 22 41  [[ 40 42 36 27 56 25 ]]  !jvms: VarHandleReferences$FieldInstanceReadWrite::compareAndSet @ bci:44 (line 180) VarHandleGuards::guard_LLL_Z @ bci:50 (line 68) Example::testCompareAndSwap @ bci:6 (line 20)

After this changeset, we get:

 R10     37  zCompareAndSwapP  === 28 35 38 54 22 41  [[ 40 42 36 27 56 25 ]]  barrier(strong )  !jvms: VarHandleReferences$FieldInstanceReadWrite::compareAndSet @ bci:44 (line 180) VarHandleGuards::guard_LLL_Z @ bci:50 (line 68) Example::testCompareAndSwap @ bci:6 (line 20)

Note the additional barrier(strong ) field in the second dump.

Testing: tier1-3 (windows-x64, linux-x64, linux-aarch64, and macosx-x64; release and debug mode).

---

Progress

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Issue

• JDK-8330153: C2: dump barrier information for all Mach nodes (Enhancement - P4)

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Tobias Hartmann (@TobiHartmann - Reviewer) ⚠️ Review applies to 409a1ef4

Reviewing

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[bridgekeeper]

👋 Welcome back rcastanedalo! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8330153: C2: dump barrier information for all Mach nodes

Reviewed-by: kvn, thartmann

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 143 new commits pushed to the master branch:

• 58ad399: 8330821: Rename UnsafeCopyMemory
• 1d52234: 8330704: Clean up non-standard use of /** comments in some langtools tests
• 83c74d7: 8329717: Missing @since tags in elements in DocumentationTool and Taglet
• 0b9350e: 8322992: Javac fails with StackOverflowError when compiling deeply nested synchronized blocks
• 20be5e0: 8314846: Do not store Klass::_secondary_super_cache in CDS archive
• 7e421ce: 8330585: Refactor/rename forwardee handling
• 3e65d90: 8330820: Remove remnants of operator_new.cpp in build system
• 936a47d: 8330607: Deprecate -XX:+UseEmptySlotsInSupers
• ee7b2e9: 8330051: Small ObjectMonitor spinning code cleanups
• 3e185c7: 8330154: Serial: Remove TenuredSpace::update_for_block
• ... and 133 more: https://git.openjdk.org/jdk/compare/b04b3047ff5c5526bdf47925210e2a35ca191e6e...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

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[openjdk]

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[mlbridge]

Webrevs

• 02: Full - Incremental (a842cb68)
• 01: Full - Incremental (409a1ef4)
• 00: Full (b856d41f)

[vnkozlov]

Can you add a simple IR test to show case it?

[robcasloz]

Can you add a simple IR test to show case it?

Done, the new test fails before this change and passes afterwards.

[TobiHartmann]

Looks good to me.

[robcasloz]

Thanks for reviewing, Tobias!

@vnkozlov: I added a simple IR test as requested, could I get a second review? Thanks!

[vnkozlov]

I don't see GHA testing for this repo. Did you enabled it?

[vnkozlov]

Good.

[robcasloz]

I don't see GHA testing for this repo. Did you enabled it?

Interesting. GHA testing is enabled for the repo (see https://github.com/robcasloz/jdk/actions), but it seems to run only for some branches, see e.g. my recent PR #18108 from the same repo. I will investigate.

[robcasloz]

Thanks for reviewing, Vladimir!

[robcasloz]

/integrate

[openjdk]

Going to push as commit 57ebd04.
Since your change was applied there have been 143 commits pushed to the master branch:

• 58ad399: 8330821: Rename UnsafeCopyMemory
• 1d52234: 8330704: Clean up non-standard use of /** comments in some langtools tests
• 83c74d7: 8329717: Missing @since tags in elements in DocumentationTool and Taglet
• 0b9350e: 8322992: Javac fails with StackOverflowError when compiling deeply nested synchronized blocks
• 20be5e0: 8314846: Do not store Klass::_secondary_super_cache in CDS archive
• 7e421ce: 8330585: Refactor/rename forwardee handling
• 3e65d90: 8330820: Remove remnants of operator_new.cpp in build system
• 936a47d: 8330607: Deprecate -XX:+UseEmptySlotsInSupers
• ee7b2e9: 8330051: Small ObjectMonitor spinning code cleanups
• 3e185c7: 8330154: Serial: Remove TenuredSpace::update_for_block
• ... and 133 more: https://git.openjdk.org/jdk/compare/b04b3047ff5c5526bdf47925210e2a35ca191e6e...master

Your commit was automatically rebased without conflicts.

[openjdk]

@robcasloz Pushed as commit 57ebd04.

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