Package ghidra.pcode.struct

Annotation Interface StructuredSleigh.StructuredUserop

Enclosing class:
StructuredSleigh
@Retention(RUNTIME) @Target(METHOD) protected static @interface StructuredSleigh.StructuredUserop
"Export" a method as a p-code userop implemented using p-code compiled from structured Sleigh

This is applied to methods used to generate Sleigh source code. Take note that the method is only invoked once (for a given library instance) to generate code. Thus, beware of non-determinism during code generation. For example, implementing something like rdrnd in structured Sleigh is rife with peril. Take the following implementation: 

 @StructuredUserop
 public void rdrnd() {
        r0.set(Random.nextLong()); // BAD: Die rolled once at compile time
 }

The random number will be generated once at structured Sleigh compilation time, and then that same number used on every invocation of the p-code userop. Instead, this userop should be implemented using a Java callback, i.e., AnnotatedPcodeUseropLibrary.PcodeUserop.

The userop may accept parameters and return a result. To accept parameters, declare them in the Java method signature and annotate them with StructuredSleigh.Param. To return a result, name the appropriate type in the type() attribute and use StructuredSleigh._result(RVal). The Java return type of the method must still be void. Note that parameters are passed by reference, so results can also be communicated by setting a parameter's value.

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    String
    type
    The data type path for the "return type" of the userop.