HeapNEWARRAY.java

package com.foursquare.heapaudit;

import org.objectweb.asm.Label;
import org.objectweb.asm.MethodAdapter;
import org.objectweb.asm.Opcodes;

class HeapNEWARRAY extends HeapUtil {

    // Allocations by NEWARRAY are triggered via calls to visitIntInsn where the
    // top of the stack contains the number of elements in the array and returns
    // a reference to the newly allocated array object.

    static void before(boolean debug,
                       boolean trace,
                       MethodAdapter mv,
                       int operand) {

        log(debug,
            trace,
            mv,
            "\tNEWARRAY.before(" + types[operand] + ")");

        // STACK: [...|count]
        mv.visitInsn(Opcodes.DUP);
        // STACK: [...|count|count]

    }

    static void after(boolean debug,
                      boolean trace,
                      MethodAdapter mv,
                      int operand) {

        log(debug,
            trace,
            mv,
            "\tNEWARRAY.after(" + types[operand] + ")");

        Label cleanup = new Label();

        Label finish = new Label();

        if (HeapSettings.conditional) {

            // STACK: [...|count|obj]
            visitCheck(mv,
                       cleanup);
            // STACK: [...|count|obj]

        }

        // STACK: [...|count|obj]
        mv.visitInsn(Opcodes.DUP_X1);
        // STACK: [...|obj|count|obj]
        mv.visitInsn(Opcodes.SWAP);
        // STACK: [...|obj|obj|count]
        mv.visitLdcInsn(types[operand]);
        // STACK: [...|obj|obj|count|type]
        mv.visitLdcInsn((long)-1);
        // STACK: [...|obj|obj|count|type|size]
        mv.visitMethodInsn(Opcodes.INVOKESTATIC,
                           "com/foursquare/heapaudit/HeapUtil",
                           "record",
                           "(Ljava/lang/Object;ILjava/lang/String;J)V");
        // STACK: [...|obj]

        if (HeapSettings.conditional) {

            visitCleanup(mv,
                         cleanup,
                         finish);
            // STACK: [...|count|obj]
            mv.visitInsn(Opcodes.SWAP);
            // STACK: [...|obj|count]
            mv.visitInsn(Opcodes.POP);
            // STACK: [...|obj]
            visitFinish(mv,
                        finish);
            // STACK: [...|obj]

        }

    }

    // Mappings from primitive type opcode to friendly name.

    private static final String[] types = new String[] {
        "INVALID0",
        "INVALID1",
        "INVALID2",
        "INVALID3",
        "Z",
        "C",
        "F",
        "D",
        "B",
        "S",
        "I",
        "J"
    };

}