8257848: -XX:CompileCommand=blackhole,* should be diagnostic

[shipilev]

This follows up on retroactive CSR review comments (JDK-8257827). As the result of discussion, it is decided to demote the "blackhole" compile command to diagnostic. Examples:

$ build/linux-x86_64-server-release/images/jdk/bin/java -Xcomp -XX:CompileCommand=quiet -XX:CompileCommand=blackhole,java/lang/Object.toString
OpenJDK 64-Bit Server VM warning: Blackhole compile option is diagnostic and must be enabled via -XX:+UnlockDiagnosticVMOptions

$ build/linux-x86_64-server-release/images/jdk/bin/java -Xcomp -XX:+UnlockDiagnosticVMOptions -XX:CompileCommand=quiet -XX:CompileCommand=blackhole,java/lang/Object.toString
OpenJDK 64-Bit Server VM warning: Blackhole compile option only works for methods with void type: java.lang.Object.toString()Ljava/lang/String;

New test verifies the locking/unlocking of the command.

Testing:

• ad-hoc compiler/blackhole test
• validation runs with JMH
• runs in tier1 (needs 8257805: Add compiler/blackhole tests to tier1 #1654 to be merged)

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8257848: -XX:CompileCommand=blackhole,* should be diagnostic

Reviewers

• Vladimir Ivanov (@iwanowww - Reviewer) ⚠️ Review applies to cbc0786

Download

$ git fetch https://git.openjdk.java.net/jdk pull/1674/head:pull/1674
$ git checkout pull/1674

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Webrevs

• 04: Full - Incremental (71c69c3)
• 03: Full - Incremental (cbc0786)
• 02: Full - Incremental (b2da3cd)
• 01: Full - Incremental (79e1015)
• 00: Full (cb4f53a)

[openjdk]

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

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

8257848: -XX:CompileCommand=blackhole,* should be diagnostic

Reviewed-by: vlivanov

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At the time when this comment was updated there had been 5 new commits pushed to the master branch:

• d2b6619: 8242258: (jrtfs) Path::toUri throws AssertionError for malformed input
• 52ab721: 8254733: HotSpot Style Guide should permit using range-based for loops
• 1d0adbb: 8253644: C2: assert(skeleton_predicate_has_opaque(iff)) failed: unexpected
• 51ac376: 8256411: Based anonymous classes have a weird end position
• 0b6b6eb: 8257813: [redo] C2: Filter type in PhiNode::Value() for induction variables of trip-counted integer loops

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[vnkozlov]

Do you need to update blackhole tests to add -XX:+UnlockDiagnosticVMOptions?

[shipilev]

Do you need to update blackhole tests to add -XX:+UnlockDiagnosticVMOptions?

They already have it, because they use -XX:+AbortVMOnCompilationFailure.

[shipilev]

There is one unrelated x86_32 test failure, otherwise tests are clean.

/integrate

[openjdk]

@shipilev Since your change was applied there have been 5 commits pushed to the master branch:

• d2b6619: 8242258: (jrtfs) Path::toUri throws AssertionError for malformed input
• 52ab721: 8254733: HotSpot Style Guide should permit using range-based for loops
• 1d0adbb: 8253644: C2: assert(skeleton_predicate_has_opaque(iff)) failed: unexpected
• 51ac376: 8256411: Based anonymous classes have a weird end position
• 0b6b6eb: 8257813: [redo] C2: Filter type in PhiNode::Value() for induction variables of trip-counted integer loops

Your commit was automatically rebased without conflicts.

Pushed as commit 35e8153.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[vnkozlov]

Do you need to update blackhole tests to add -XX:+UnlockDiagnosticVMOptions?

They already have it, because they use -XX:+AbortVMOnCompilationFailure.

Good.