Review request: update javac to properly output mandated parameters in MethodParameters attributes (original) (raw)

Alex Buckley alex.buckley at oracle.com
Thu Feb 7 14:41:03 PST 2013

On 2/7/2013 2:17 PM, Maurizio Cimadamore wrote:

*) (effectively) final variables passed in to inner classes (javac only does that for reference-types as others are just constants that can be produced on the stack at will)

Right. The JLS does not say that those ctor parameters are implicitly declared. javac should mark them with ACCSYNTHETIC. So that we are clear - javac is already marking all this stuff I'm saying as ACCSYNTHETIC. But Eric's code is implicitly tagging it as ACCMANDATED too, which is where I think the problem lies.

I had not thought of a class file construct being marked as both. I should disallow that in the JVMS; however, enforcement would be the responsibility of core reflection. I have a feeling that Parameter.isSynthetic() is never really going to throw an exception just because ACC_MANDATED is set. Similarly for isMandated() and ACC_SYNTHETIC. So, I will not disallow it in the JVMS. If you can't trust a Java compiler, who can you trust?

*) I believe javac's generated enum constructor has an additional parameter accepting the ordinal enum Test { FOO { }, BAR { }; } javap -p Test Compiled from "Test.java" class Test extends java.lang.Enum { public static final Test FOO; public static final Test BAR; public static Test[] values(); public static Test valueOf(java.lang.String); Test(java.lang.String, int, Test$1); static {}; } And also, enum Test { Test() { } } that generates: Compiled from "Test.java" class Test extends java.lang.Enum { public static final Test Test; public static Test[] values(); public static Test valueOf(java.lang.String); Test(java.lang.String, int, Test$1); static {}; }

Thanks for this. Since the compiler processing the expression "Test.FOO" could be different to the compiler which emitted Test.class, there must be a standard way for the Test.FOO compiler to indicate which Test constant ought to be instantiated. I will consult with Eclipse ASAP. I expect both the String and int parameters will end up as implicitly declared.

Alex

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