VM_MultianewarrayHelper.java

/*
 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
 *
 *  This file is licensed to You under the Common Public License (CPL);
 *  You may not use this file except in compliance with the License. You
 *  may obtain a copy of the License at
 *
 *      http://www.opensource.org/licenses/cpl1.0.php
 *
 *  See the COPYRIGHT.txt file distributed with this work for information
 *  regarding copyright ownership.
 */
package org.jikesrvm.ia32;

import org.jikesrvm.VM;
import org.jikesrvm.classloader.VM_Array;
import org.jikesrvm.classloader.VM_TypeReference;
import org.jikesrvm.runtime.VM_Magic;
import org.jikesrvm.runtime.VM_Runtime;
import org.vmmagic.unboxed.Address;
import org.vmmagic.unboxed.LocalAddress;

/**
 * Helper routine to pull the parameters to multianewarray off the
 * Java expression stack maintained by the baseline compiler and
 * pass them to VM_Runtime.buildMultiDimensionalArray.
 *
 * TODO: There is only 1 line of platform dependent code here; refactor?
 */
public abstract class VM_MultianewarrayHelper {

  /**
   * Allocate something like "new Foo[cnt0][cnt1]...[cntN-1]",
   *                      or "new int[cnt0][cnt1]...[cntN-1]".
   * @param methodId method id of caller
   * @param numDimensions number of array dimensions
   * @param typeId type id of type reference for array
   * @param argOffset position of word *above* `cnt0' argument within
   * caller's frame This is used to access the number of elements to
   * be allocated for each dimension.
   *
   * See also: bytecode 0xc5 ("multianewarray") in VM_Compiler
   */
  static Object newArrayArray(int methodId, int numDimensions, int typeId, int argOffset)
      throws NoClassDefFoundError, NegativeArraySizeException, OutOfMemoryError {
    // fetch number of elements to be allocated for each array dimension
    //
    int[] numElements = new int[numDimensions];
    
    VM.disableGC();
    LocalAddress argp = VM_Magic.getFramePointer().plus(argOffset);
    for (int i = 0; i < numDimensions; ++i) {
      argp = argp.minus(4);
      numElements[i] = argp.loadInt();
    }
    VM.enableGC();

    // validate arguments
    //
    for (int i = 0; i < numDimensions; ++i) {
      if (numElements[i] < 0) throw new NegativeArraySizeException();
    }

    // create array
    //
    VM_TypeReference tRef = VM_TypeReference.getTypeRef(typeId);
    VM_Array array = tRef.resolve(false).asArray();
    return VM_Runtime.buildMultiDimensionalArray(methodId, numElements, array);
  }
}