8340398: [JVMCI] Unintuitive behavior of UseJVMCICompiler option

[toddjonker]

Clean backport of patch authored by @tzezula and approved by @dougxc

The patch default-enables useJVMCINativeLibrary when EnableJVMCI is on and libgraal present. While this is a behavior change, it seems unlikely that users would deploy libgraal and not want it used by JVMCI.

This streamlines configuration of our JDK+Graal distro, which in turn allows two failing tests to pass without modification.

Equivalent backport to 23: openjdk/jdk23u#136

---

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Issue

• JDK-8340398: [JVMCI] Unintuitive behavior of UseJVMCICompiler option (Bug - P4 - Approved)

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[openjdk]

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8340398: [JVMCI] Unintuitive behavior of UseJVMCICompiler option

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At the time when this comment was updated there had been 47 new commits pushed to the master branch:

• c62b0a5: 8325610: CTW: Add StressIncrementalInlining to stress options
• a2f0ddb: 8325762: Use PassFailJFrame.Builder.splitUI() in PrintLatinCJKTest.java
• 5013360: 8341806: Gcc version detection failure on Alinux3
• 3fc07f2: 8341688: Aarch64: Generate comments in -XX:+PrintInterpreter to link to source code
• 27d2abe: 8320892: AArch64: Restore FPU control state after JNI
• fe4b0fa: 8332866: Crash in ImageIO JPEG decoding when MEM_STATS in enabled
• dd4e0ae: 8341261: Tests assume UnlockExperimentalVMOptions is disabled by default
• f19e69a: 8342014: RISC-V: ZStoreBarrierStubC2 clobbers rflags
• 70eff9d: 8340109: Ubsan: ciEnv.cpp:1660:65: runtime error: member call on null pointer of type 'struct CompileTask'
• 6ed940b: 8320682: [AArch64] C1 compilation fails with "Field too big for insn"
• ... and 37 more: https://git.openjdk.org/jdk21u-dev/compare/e24138546c51ee39ae262a3ba762dc7e928209dc...master

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[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

⚠️ @toddjonker This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

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• 00: Full (757df9c8)

[toddjonker]

/approval request This streamlines configuration of our JDK+Graal distro, which in turn allows two failing tests to pass without modification. A corresponding backport PR for JDK23 is openjdk/jdk23u#136

[openjdk]

@toddjonker
8340398: The approval request has been created successfully.

[GoeLin]

Hi Todd,
I'm not sure this is a good candidate for backport.
As you say, it will change the way the compilers are loaded and operated.
This might be quite unexpected for graal/truffle users if they update from 21.0.5 to 21.0.6.

Also, how did you test this backport?

[toddjonker]

Hi Goetz,

I understand there's judgement call here.

The PR changes the behavior when:

• the user has specified +XX:EnableJVMCI but does not configure useJVMCINativeLibrary either way; and
• the runtime image has libgraal.

Currently, libgraal won't be enabled in that scenario. After this change, enabling JVMC auto-enables libgraal use when it is present. I agree with the original author that using the faster implementation a better default.

Coming from the perspective of a Truffle user may be more convincing. The current behavior is such that adding -XX:useJVMCINativeLibrary to either +XX:EnableJVMCI or +XX:EnableJVMCIProduct has the surprising side effect of disabling libgraal for Truffle.

While this is a behavior change, it seems unlikely that users would deploy libgraal and not want it used by JVMCI. (Certainly a Truffle user will want it!)

BTW, I run tiers 1-3 on linux-x86_64-server-release and all pass modulo two tests that are known to fail in our environment.

[GoeLin]

Thanks. Ok, so let's go that way.

[toddjonker]

Thanks Goetz!

[toddjonker]

/integrate

[openjdk]

@toddjonker
Your change (at version 757df9c) is now ready to be sponsored by a Committer.

[Rudometov]

/sponsor

[openjdk]

Going to push as commit b010fdc.
Since your change was applied there have been 47 commits pushed to the master branch:

• c62b0a5: 8325610: CTW: Add StressIncrementalInlining to stress options
• a2f0ddb: 8325762: Use PassFailJFrame.Builder.splitUI() in PrintLatinCJKTest.java
• 5013360: 8341806: Gcc version detection failure on Alinux3
• 3fc07f2: 8341688: Aarch64: Generate comments in -XX:+PrintInterpreter to link to source code
• 27d2abe: 8320892: AArch64: Restore FPU control state after JNI
• fe4b0fa: 8332866: Crash in ImageIO JPEG decoding when MEM_STATS in enabled
• dd4e0ae: 8341261: Tests assume UnlockExperimentalVMOptions is disabled by default
• f19e69a: 8342014: RISC-V: ZStoreBarrierStubC2 clobbers rflags
• 70eff9d: 8340109: Ubsan: ciEnv.cpp:1660:65: runtime error: member call on null pointer of type 'struct CompileTask'
• 6ed940b: 8320682: [AArch64] C1 compilation fails with "Field too big for insn"
• ... and 37 more: https://git.openjdk.org/jdk21u-dev/compare/e24138546c51ee39ae262a3ba762dc7e928209dc...master

Your commit was automatically rebased without conflicts.

[openjdk]

@Rudometov @toddjonker Pushed as commit b010fdc.

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