[lworld] RFR: 8281763: Support Valhalla class file features in asmtools

[Dan Smith]

On Mon, 14 Feb 2022 20:48:06 GMT, Dan Smith <dlsmith at openjdk.org> wrote:

> Modifying the Valhalla repo's fork of asmtools to implement Valhalla class file features:
> 
> - ACC_VALUE, ACC_PERMITS_VALUE, and ACC_PRIMITIVE 
> - Preload attribute 
> - aconst_init & withfield instructions 
> - Unnamed factory methods 
> - Q descriptors
> 
> Mainly relevant to the `jasm` tool, but there are also some interactions with `jdis` and `jdec`. No impact on `jcod`.

I don't think we typically write tests for our testing code, but here's an example that can be used to manually sanity-check the behavior:


/**
 * @test
 * @summary Make sure custom jasm works
 * @library /test/lib
 * @build org.openjdk.asmtools.* org.openjdk.asmtools.jasm.*
 * @run driver org.openjdk.asmtools.JtregDriver jasm -strict JasmTest.jasm
 * @run main JasmTest
 */
 
public final primitive value class JasmTest version 62:0 {

    Preload java/lang/String;
    
    private final Field x:I;
    
    public static Method make:"(I)QJasmTest;" stack 2 {
        aconst_init JasmTest;
        iload_0;
        withfield x:I;
        areturn;
    }
    
    public static Method id:"(QJasmTest;)QJasmTest;" stack 1 {
        aload_0;
        areturn;
    }
    
    public static Method fail:"()V" stack 2 {
        new java/lang/RuntimeException;
        dup;
        invokespecial java/lang/RuntimeException.<init>:"()V";
        athrow;
    }

    public static Method main:"([Ljava/lang/String;)V" stack 1 {
        //invokestatic fail:"()V";
        iconst_2;
        invokestatic make:"(I)QJasmTest;";
        pop;
        return;
    }

}

-------------

PR: https://git.openjdk.java.net/valhalla/pull/647