1 /*
   2  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "ci/ciArray.hpp"
  27 #include "ci/ciArrayKlass.hpp"
  28 #include "ci/ciConstant.hpp"
  29 #include "ci/ciKlass.hpp"
  30 #include "ci/ciUtilities.hpp"
  31 #include "oops/objArrayOop.hpp"
  32 #include "oops/typeArrayOop.hpp"
  33 
  34 // ciArray
  35 //
  36 // This class represents an arrayOop in the HotSpot virtual
  37 // machine.
  38 static BasicType fixup_element_type(BasicType bt) {
  39   if (bt == T_ARRAY)    return T_OBJECT;
  40   if (bt == T_BOOLEAN)  return T_BYTE;
  41   return bt;
  42 }
  43 
  44 ciConstant ciArray::element_value_impl(BasicType elembt,
  45                                        arrayOop ary,
  46                                        int index) {
  47   if (ary == NULL)
  48     return ciConstant();
  49   assert(ary->is_array(), "");
  50   if (index < 0 || index >= ary->length())
  51     return ciConstant();
  52   ArrayKlass* ak = (ArrayKlass*) ary->klass();
  53   BasicType abt = ak->element_type();
  54   if (fixup_element_type(elembt) !=
  55       fixup_element_type(abt))
  56     return ciConstant();
  57   switch (elembt) {
  58   case T_ARRAY:
  59   case T_OBJECT:
  60     {
  61       assert(ary->is_objArray(), "");
  62       objArrayOop objary = (objArrayOop) ary;
  63       oop elem = objary->obj_at(index);
  64       ciEnv* env = CURRENT_ENV;
  65       ciObject* box = env->get_object(elem);
  66       return ciConstant(T_OBJECT, box);
  67     }
  68   }
  69   assert(ary->is_typeArray(), "");
  70   typeArrayOop tary = (typeArrayOop) ary;
  71   jint value = 0;
  72   switch (elembt) {
  73   case T_LONG:          return ciConstant(tary->long_at(index));
  74   case T_FLOAT:         return ciConstant(tary->float_at(index));
  75   case T_DOUBLE:        return ciConstant(tary->double_at(index));
  76   default:              return ciConstant();
  77   case T_BYTE:          value = tary->byte_at(index);           break;
  78   case T_BOOLEAN:       value = tary->byte_at(index) & 1;       break;
  79   case T_SHORT:         value = tary->short_at(index);          break;
  80   case T_CHAR:          value = tary->char_at(index);           break;
  81   case T_INT:           value = tary->int_at(index);            break;
  82   }
  83   return ciConstant(elembt, value);
  84 }
  85 
  86 // ------------------------------------------------------------------
  87 // ciArray::element_value
  88 //
  89 // Current value of an element.
  90 // Returns T_ILLEGAL if there is no element at the given index.
  91 ciConstant ciArray::element_value(int index) {
  92   BasicType elembt = element_basic_type();
  93   GUARDED_VM_ENTRY(
  94     return element_value_impl(elembt, get_arrayOop(), index);
  95   )
  96 }
  97 
  98 // ------------------------------------------------------------------
  99 // ciArray::element_value_by_offset
 100 //
 101 // Current value of an element at the specified offset.
 102 // Returns T_ILLEGAL if there is no element at the given offset.
 103 ciConstant ciArray::element_value_by_offset(intptr_t element_offset) {
 104   BasicType elembt = element_basic_type();
 105   intptr_t shift  = exact_log2(type2aelembytes(elembt));
 106   intptr_t header = arrayOopDesc::base_offset_in_bytes(elembt);
 107   intptr_t index = (element_offset - header) >> shift;
 108   intptr_t offset = header + ((intptr_t)index << shift);
 109   if (offset != element_offset || index != (jint)index)
 110     return ciConstant();
 111   return element_value((jint) index);
 112 }
 113 
 114 // ------------------------------------------------------------------
 115 // ciArray::print_impl
 116 //
 117 // Implementation of the print method.
 118 void ciArray::print_impl(outputStream* st) {
 119   st->print(" length=%d type=", length());
 120   klass()->print(st);
 121 }