public final VM_Address allocFast(boolean isScalar, int bytes, boolean inGC)
public final VM_Address allocFast(int bytes, int align, int offset, boolean inGC)
  public final VM_Address allocFast(boolean isScalar, int bytes, boolean inGC)     throws VM_PragmaInline {    int sizeClass = getSizeClass(bytes);    VM_Address cell = freeList.get(sizeClass);    if (!cell.isZero()) {      if (maintainInUse()) cellsInUse[sizeClass]++;      freeList.set(sizeClass, getNextCell(cell));      setNextCell(cell, VM_Address.zero()); // clear out the free list link      postAlloc(cell, currentBlock.get(sizeClass), sizeClass, bytes, inGC);    }     return cell;  }