[JDK8] RFR (XS): JSR292: IncompatibleClassChangeError in LambdaForm for CharSequence.toString() method handle type converter (original) (raw)

Vladimir Ivanov vladimir.x.ivanov at oracle.com
Thu Jan 16 01:37:43 PST 2014

Jochen,

The test provokes the bug, since it sets compilation threshold to 0: -Djava.lang.invoke.MethodHandle.COMPILE_THRESHOLD=0

Best regards, Vladimir Ivanov

On 1/16/14 12:40 PM, Jochen Theodorou wrote:

Hi,

since I am indirectly the reporter of this bug I have one remark for the test. The error happens only for compiled lambda forms. The given test does imho not use a compiled lambda form. In other words, afaik the test would pass without the fix. As such it would be useless as regression test. Am 15.01.2014 16:31, schrieb Vladimir Ivanov: http://cr.openjdk.java.net/~vlivanov/8031502/webrev.00/ https://bugs.openjdk.java.net/browse/JDK-8031502

InvokeBytecodeGenerator can produce incorrect bytecode for a LambdaForm when invoking a method from Object declared in an interface. The problem is the following: (1) java.lang.CharSequence interface declares abstract method "String toString()"; (2) after 8014013 fix, VM resolves CharSequence::toString()/invokeInterface to CharSequence::toString()/invokeVirtual; (3) during LambdaForm compilation, CharSequence is considered statically invocable (see InvokeBytecodeGenerator::isStaticallyInvocable) and invokevirtual for CharSequence::toString() is issued, which is wrong (invokevirtual throws ICCE if it references an interface); The fix is straightforward: during LambdaForm compilation, switch back from invokevirtual to invokeinterface instruction when invoking a method on an interface. The fix is targeted for 8. Will be also integrated into 9. Testing: regression test, jdk/test/java/lang/invoke, vm.mlvm.testlist, nashorn, jruby. Thanks! Best regards, Vladimir Ivanov

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