8284848: C2: Compiler blackhole arguments should be treated as globally escaping

[shipilev]

Blackholes should make the arguments to be treated as globally escaping, to match the expected behavior of legacy JMH blackholes. See more discussion in the bug.

Additional testing:

• Linux x86_64 fastdebug tier1
• Linux x86_64 fastdebug tier2
• OpenJDK microbenchmark corpus sanity run

---

Progress

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Issue

• JDK-8284848: C2: Compiler blackhole arguments should be treated as globally escaping

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Tobias Hartmann (@TobiHartmann - Reviewer) ⚠️ Review applies to cb8085f

Reviewing

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[openjdk]

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[mlbridge]

Webrevs

• 03: Full - Incremental (a2f0001f)
• 02: Full - Incremental (cb8085f8)
• 01: Full - Incremental (3e0a2c28)
• 00: Full (c3e82437)

[vnkozlov]

Yes, this looks good. And thank you for adding IR tests to verify it.

[vnkozlov]

Looks good. Let me test it before approval.

[vnkozlov]

Got failure in new tests when run with -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -XX:-TieredCompilation.

BlackholeSyncEATest.java failed:

Failed IR Rules (2) of Methods (1)
----------------------------------
1) Method "static void compiler.c2.irTests.blackhole.BlackholeSyncEATest.testBlackholed()" - [Failed IR rules: 2]:
   * @IR rule 1: "@compiler.lib.ir_framework.IR(applyIf={}, applyIfAnd={}, failOn={}, applyIfOr={}, counts={"(\\\\d+(\\\\s){2}(FastLock.*)+(\\\\s){2}===.*)", "1"}, applyIfNot={})"
     - counts: Graph contains wrong number of nodes:
       * Regex 1: (\\d+(\\s){2}(FastLock.*)+(\\s){2}===.*)
         - Failed comparison: [found] 0 = 1 [given]
         - No nodes matched!
   * @IR rule 2: "@compiler.lib.ir_framework.IR(applyIf={}, applyIfAnd={}, failOn={}, applyIfOr={}, counts={"(\\\\d+(\\\\s){2}(FastUnlock.*)+(\\\\s){2}===.*)", "1"}, applyIfNot={})"
     - counts: Graph contains wrong number of nodes:
       * Regex 1: (\\d+(\\s){2}(FastUnlock.*)+(\\s){2}===.*)
         - Failed comparison: [found] 0 = 1 [given]
         - No nodes matched!
         
Compilation(s) of failed match(es):
>>> Compilation of static void compiler.c2.irTests.blackhole.BlackholeSyncEATest.testBlackholed():
PrintIdeal:
 3  Start  ===  3  0  [[ 3  5  6  7  8  9 ]]  #{0:control, 1:abIO, 2:memory, 3:rawptr:BotPTR, 4:return_address}
 9  Parm  ===  3  [[ 105 ]] ReturnAdr !jvms: BlackholeSyncEATest::testBlackholed @ bci:-1 (line 75)
 8  Parm  ===  3  [[ 105 ]] FramePtr !jvms: BlackholeSyncEATest::testBlackholed @ bci:-1 (line 75)
 7  Parm  ===  3  [[ 105 ]] Memory  Memory: @BotPTR *+bot, idx=Bot; !orig=[34],40 !jvms: BlackholeSyncEATest::testBlackholed @ bci:-1 (line 75)
 6  Parm  ===  3  [[ 105 ]] I_O !orig=[35] !jvms: BlackholeSyncEATest::testBlackholed @ bci:-1 (line 75)
 5  Parm  ===  3  [[ 105 ]] Control !orig=[29],[38],[79],[83],[87],[91] !jvms: BlackholeSyncEATest::testBlackholed @ bci:-1 (line 75)
 105  Return  ===  5  6  7  8  9  [[ 0 ]] 
 0  Root  ===  0  105  [[ 0  1  3  20  21  22  108  107 ]] inner 

BlackholeStoreStoreEATest.java:

Failed IR Rules (1) of Methods (1)
----------------------------------
1) Method "static void compiler.c2.irTests.blackhole.BlackholeStoreStoreEATest.testBlackholed()" - [Failed IR rules: 1]:
   * @IR rule 1: "@compiler.lib.ir_framework.IR(failOn={}, applyIf={}, applyIfAnd={}, applyIfOr={}, counts={"(\\\\d+(\\\\s){2}(MemBarStoreStore.*)+(\\\\s){2}===.*)", "1"}, applyIfNot={})"
     - counts: Graph contains wrong number of nodes:
       * Regex 1: (\\d+(\\s){2}(MemBarStoreStore.*)+(\\s){2}===.*)
         - Failed comparison: [found] 0 = 1 [given]
         - No nodes matched!

Compilation(s) of failed match(es):
>>> Compilation of static void compiler.c2.irTests.blackhole.BlackholeStoreStoreEATest.testBlackholed():
PrintIdeal:
 3  Start  ===  3  0  [[ 3  5  6  7  8  9 ]]  #{0:control, 1:abIO, 2:memory, 3:rawptr:BotPTR, 4:return_address}
 9  Parm  ===  3  [[ 89 ]] ReturnAdr !jvms: BlackholeStoreStoreEATest::testBlackholed @ bci:-1 (line 55)
 8  Parm  ===  3  [[ 89 ]] FramePtr !jvms: BlackholeStoreStoreEATest::testBlackholed @ bci:-1 (line 55)
 7  Parm  ===  3  [[ 89 ]] Memory  Memory: @BotPTR *+bot, idx=Bot; !orig=[34],40 !jvms: BlackholeStoreStoreEATest::testBlackholed @ bci:-1 (line 55)
 6  Parm  ===  3  [[ 89 ]] I_O !orig=[35] !jvms: BlackholeStoreStoreEATest::testBlackholed @ bci:-1 (line 55)
 5  Parm  ===  3  [[ 89 ]] Control !orig=[29],[38] !jvms: BlackholeStoreStoreEATest::testBlackholed @ bci:-1 (line 55)
 89  Return  ===  5  6  7  8  9  [[ 0 ]] 
 0  Root  ===  0  89  [[ 0  1  3  20  21  22  91  92 ]] inner 

[shipilev]

Got failure in new tests when run with -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -XX:-TieredCompilation.

Turns out to be a separate bug, JDK-8284848, PR #8344. Need to fix that one first.

[TobiHartmann]

Looks good.

[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:

8284848: C2: Compiler blackhole arguments should be treated as globally escaping

Reviewed-by: kvn, thartmann

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[shipilev]

Got failure in new tests when run with -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -XX:-TieredCompilation.

Turns out to be a separate bug, JDK-8284848, PR #8344. Need to fix that one first.

Merged from master, so this fix should now be in this PR base. I checked new tests work with the VM options above.

[vnkozlov]

Good.

[shipilev]

Thanks for reviews! It seems to work as expected in the benchmarks.

/integrate

[openjdk]

Going to push as commit 5629c75.
Since your change was applied there have been 66 commits pushed to the master branch:

• 85f8d14: 8283994: Make Xerces DatatypeException stackless
• 4f2e4c7: 8178969: [TESTBUG] Wrong reporting of gc/g1/humongousObjects/TestHeapCounters test.
• 4795165: 8285696: AlgorithmConstraints:permits not throwing IllegalArgumentException when 'alg' is null
• c1173c2: 8285493: ECC calculation error
• 89fd6d3: 8284910: Buffer clean in PasswordCallback
• cf1b00a: 8285683: Missing @ since 11 in java.security.spec.MGF1ParameterSpec fields
• 3312d8c: 8285756: clean up use of bad arguments for @clean in langtools tests
• 5c09349: 8285032: vmTestbase/nsk/jdi/EventSet/suspendPolicy/suspendpolicy008/ fails with "eventSet.suspendPolicy() != policyExpected"
• 1f868f1: 8285658: Fix two typos in the spec of j.u.random.RandomGenerator
• 8a16842: 8176501: Method Shape.getBounds2D() incorrectly includes Bezier control points in bounding box
• ... and 56 more: https://git.openjdk.java.net/jdk/compare/ce8db2c40378de01ce35ca37ec315af47974d6d6...master

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev Pushed as commit 5629c75.

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