MethodHandleBuilder bug?

[Paul Sandoz]

Thanks, i think there is a bug processing the label when merging stack state from which to generate a stack map entry. Something to do with liveness… i might be able to work it out more fully... but i am not too familiar with stack map entries.

Paul.

> On Apr 12, 2018, at 7:37 AM, Roland Westrelin <rwestrel at redhat.com> wrote:
> 
> 
> I noticed that this:
> 
>    private static final MethodHandle mergeNull = MethodHandleBuilder.loadCode(MethodHandles.lookup(),
>        "mergeNull",
>        MethodType.methodType(void.class, TestLWorld.class, boolean.class),
>        CODE -> {
>            CODE.
>            iload_1().
>            iconst_0().
>            ifcmp(TypeTag.I, CondKind.EQ, "null").
>            aload_0().
>            getfield(TestLWorld.class, "valueField1", "Lcompiler/valhalla/valuetypes/MyValue1;").
>            goto_("continue").
>            label("null").
>            aconst_null().
>            label("continue").
>            aload_0().
>            swap().
>            putfield(TestLWorld.class, "valueField1", "Lcompiler/valhalla/valuetypes/MyValue1;").
>            return_();
>        }
>        );
> 
> works fine but if I swap the code in the if branches:
> 
>    private static final MethodHandle mergeNull = MethodHandleBuilder.loadCode(MethodHandles.lookup(),
>        "mergeNull",
>        MethodType.methodType(void.class, TestLWorld.class, boolean.class),
>        CODE -> {
>            CODE.
>            iload_1().
>            iconst_0().
>            ifcmp(TypeTag.I, CondKind.EQ, "null").
>            aconst_null().
>            goto_("continue").
>            label("null").
>            aload_0().
>            getfield(TestLWorld.class, "valueField1", "Lcompiler/valhalla/valuetypes/MyValue1;").
>            label("continue").
>            aload_0().
>            swap().
>            putfield(TestLWorld.class, "valueField1", "Lcompiler/valhalla/valuetypes/MyValue1;").
>            return_();
>        }
>        );
> 
> then I get:
> 
> java.lang.ExceptionInInitializerError
>        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
>        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>        at java.base/java.lang.reflect.Method.invoke(Method.java:564)
>        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:115)
>        at java.base/java.lang.Thread.run(Thread.java:841)
> Caused by: java.lang.IllegalStateException: Bad type: <null>
>        at java.base/jdk.experimental.bytecode.BasicTypeHelper.tag(BasicTypeHelper.java:76)
>        at java.base/jdk.experimental.value.MethodHandleBuilder$IsolatedMethodBuilder$IsolatedMethodTypeHelper.tag(MethodHandleBuilder.java:196)
>        at java.base/jdk.experimental.value.MethodHandleBuilder$IsolatedMethodBuilder$IsolatedMethodTypeHelper.tag(MethodHandleBuilder.java:138)
>        at java.base/jdk.experimental.bytecode.CodeBuilder.writeStackMapType(CodeBuilder.java:1257)
>        at java.base/jdk.experimental.bytecode.CodeBuilder.sameLocals1StackItemFrame(CodeBuilder.java:1305)
>        at java.base/jdk.experimental.bytecode.TypedCodeBuilder.writeStackMapFrame(TypedCodeBuilder.java:1231)
>        at java.base/jdk.experimental.bytecode.TypedCodeBuilder.emitStackMap(TypedCodeBuilder.java:1196)
>        at java.base/jdk.experimental.bytecode.TypedCodeBuilder.resolveJumps(TypedCodeBuilder.java:1189)
>        at java.base/jdk.experimental.bytecode.MacroCodeBuilder.label(MacroCodeBuilder.java:437)
>        at compiler.valhalla.valuetypes.TestLWorld.lambda$static$3(TestLWorld.java:505)
>        at java.base/jdk.experimental.bytecode.MethodBuilder.withCode(MethodBuilder.java:50)
>        at java.base/jdk.experimental.value.MethodHandleBuilder.lambda$loadCode$1(MethodHandleBuilder.java:101)
>        at java.base/jdk.experimental.bytecode.ClassBuilder.withMethod(ClassBuilder.java:204)
>        at java.base/jdk.experimental.value.MethodHandleBuilder.loadCode(MethodHandleBuilder.java:99)
>        at java.base/jdk.experimental.value.MethodHandleBuilder.loadCode(MethodHandleBuilder.java:77)
>        at java.base/jdk.experimental.value.MethodHandleBuilder.loadCode(MethodHandleBuilder.java:72)
>        at compiler.valhalla.valuetypes.TestLWorld.<clinit>(TestLWorld.java:492)
>        ... 6 more
> 
> Roland.