Fri, 12 Feb 2010 15:27:36 -0800
Merge
duke@435 | 1 | /* |
duke@435 | 2 | * Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | class jfieldIDWorkaround: AllStatic { |
duke@435 | 26 | // This workaround is because JVMTI doesn't have distinct entry points |
duke@435 | 27 | // for methods that use static jfieldIDs and instance jfieldIDs. |
duke@435 | 28 | // The workaround is to steal a low-order bit: |
duke@435 | 29 | // a 1 means the jfieldID is an instance jfieldID, |
duke@435 | 30 | // and the rest of the word is the offset of the field. |
duke@435 | 31 | // a 0 means the jfieldID is a static jfieldID, |
duke@435 | 32 | // and the rest of the word is the JNIid*. |
duke@435 | 33 | // |
duke@435 | 34 | // Another low-order bit is used to mark if an instance field |
duke@435 | 35 | // is accompanied by an indication of which class it applies to. |
duke@435 | 36 | // |
duke@435 | 37 | // Bit-format of a jfieldID (most significant first): |
duke@435 | 38 | // address:30 instance=0:1 checked=0:1 |
duke@435 | 39 | // offset:30 instance=1:1 checked=0:1 |
duke@435 | 40 | // klass:23 offset:7 instance=1:1 checked=1:1 |
duke@435 | 41 | // |
duke@435 | 42 | // If the offset does not fit in 7 bits, or if the fieldID is |
duke@435 | 43 | // not checked, then the checked bit is zero and the rest of |
duke@435 | 44 | // the word (30 bits) contains only the offset. |
duke@435 | 45 | // |
duke@435 | 46 | private: |
duke@435 | 47 | enum { |
duke@435 | 48 | checked_bits = 1, |
duke@435 | 49 | instance_bits = 1, |
duke@435 | 50 | address_bits = BitsPerWord - checked_bits - instance_bits, |
duke@435 | 51 | |
duke@435 | 52 | large_offset_bits = address_bits, // unioned with address |
duke@435 | 53 | small_offset_bits = 7, |
duke@435 | 54 | klass_bits = address_bits - small_offset_bits, |
duke@435 | 55 | |
duke@435 | 56 | checked_shift = 0, |
duke@435 | 57 | instance_shift = checked_shift + checked_bits, |
duke@435 | 58 | address_shift = instance_shift + instance_bits, |
duke@435 | 59 | |
duke@435 | 60 | offset_shift = address_shift, // unioned with address |
duke@435 | 61 | klass_shift = offset_shift + small_offset_bits, |
duke@435 | 62 | |
duke@435 | 63 | checked_mask_in_place = right_n_bits(checked_bits) << checked_shift, |
duke@435 | 64 | instance_mask_in_place = right_n_bits(instance_bits) << instance_shift, |
duke@435 | 65 | #ifndef _WIN64 |
duke@435 | 66 | large_offset_mask = right_n_bits(large_offset_bits), |
duke@435 | 67 | small_offset_mask = right_n_bits(small_offset_bits), |
duke@435 | 68 | klass_mask = right_n_bits(klass_bits) |
duke@435 | 69 | #endif |
duke@435 | 70 | }; |
duke@435 | 71 | |
duke@435 | 72 | #ifdef _WIN64 |
duke@435 | 73 | // These values are too big for Win64 |
duke@435 | 74 | const static uintptr_t large_offset_mask = right_n_bits(large_offset_bits); |
duke@435 | 75 | const static uintptr_t small_offset_mask = right_n_bits(small_offset_bits); |
duke@435 | 76 | const static uintptr_t klass_mask = right_n_bits(klass_bits); |
duke@435 | 77 | #endif |
duke@435 | 78 | |
duke@435 | 79 | // helper routines: |
duke@435 | 80 | static bool is_checked_jfieldID(jfieldID id) { |
duke@435 | 81 | uintptr_t as_uint = (uintptr_t) id; |
duke@435 | 82 | return ((as_uint & checked_mask_in_place) != 0); |
duke@435 | 83 | } |
duke@435 | 84 | static intptr_t raw_instance_offset(jfieldID id) { |
duke@435 | 85 | uintptr_t result = (uintptr_t) id >> address_shift; |
duke@435 | 86 | if (VerifyJNIFields && is_checked_jfieldID(id)) { |
duke@435 | 87 | result &= small_offset_mask; // cut off the hash bits |
duke@435 | 88 | } |
duke@435 | 89 | return (intptr_t)result; |
duke@435 | 90 | } |
duke@435 | 91 | static intptr_t encode_klass_hash(klassOop k, intptr_t offset); |
duke@435 | 92 | static bool klass_hash_ok(klassOop k, jfieldID id); |
duke@435 | 93 | static void verify_instance_jfieldID(klassOop k, jfieldID id); |
duke@435 | 94 | |
duke@435 | 95 | public: |
duke@435 | 96 | static bool is_valid_jfieldID(klassOop k, jfieldID id); |
duke@435 | 97 | |
duke@435 | 98 | static bool is_instance_jfieldID(klassOop k, jfieldID id) { |
duke@435 | 99 | uintptr_t as_uint = (uintptr_t) id; |
duke@435 | 100 | return ((as_uint & instance_mask_in_place) != 0); |
duke@435 | 101 | } |
duke@435 | 102 | static bool is_static_jfieldID(jfieldID id) { |
duke@435 | 103 | uintptr_t as_uint = (uintptr_t) id; |
duke@435 | 104 | return ((as_uint & instance_mask_in_place) == 0); |
duke@435 | 105 | } |
duke@435 | 106 | |
duke@435 | 107 | static jfieldID to_instance_jfieldID(klassOop k, int offset) { |
duke@435 | 108 | intptr_t as_uint = ((offset & large_offset_mask) << offset_shift) | instance_mask_in_place; |
duke@435 | 109 | if (VerifyJNIFields) { |
duke@435 | 110 | as_uint |= encode_klass_hash(k, offset); |
duke@435 | 111 | } |
duke@435 | 112 | jfieldID result = (jfieldID) as_uint; |
duke@435 | 113 | #ifndef ASSERT |
duke@435 | 114 | // always verify in debug mode; switchable in anything else |
duke@435 | 115 | if (VerifyJNIFields) |
duke@435 | 116 | #endif // ASSERT |
duke@435 | 117 | { |
duke@435 | 118 | verify_instance_jfieldID(k, result); |
duke@435 | 119 | } |
duke@435 | 120 | assert(raw_instance_offset(result) == (offset & large_offset_mask), "extract right offset"); |
duke@435 | 121 | return result; |
duke@435 | 122 | } |
duke@435 | 123 | |
duke@435 | 124 | static intptr_t from_instance_jfieldID(klassOop k, jfieldID id) { |
duke@435 | 125 | #ifndef ASSERT |
duke@435 | 126 | // always verify in debug mode; switchable in anything else |
duke@435 | 127 | if (VerifyJNIFields) |
duke@435 | 128 | #endif // ASSERT |
duke@435 | 129 | { |
duke@435 | 130 | verify_instance_jfieldID(k, id); |
duke@435 | 131 | } |
duke@435 | 132 | return raw_instance_offset(id); |
duke@435 | 133 | } |
duke@435 | 134 | |
duke@435 | 135 | static jfieldID to_static_jfieldID(JNIid* id) { |
duke@435 | 136 | assert(id->is_static_field_id(), "from_JNIid, but not static field id"); |
duke@435 | 137 | jfieldID result = (jfieldID) id; |
duke@435 | 138 | assert(from_static_jfieldID(result) == id, "must produce the same static id"); |
duke@435 | 139 | return result; |
duke@435 | 140 | } |
duke@435 | 141 | |
duke@435 | 142 | static JNIid* from_static_jfieldID(jfieldID id) { |
duke@435 | 143 | assert(jfieldIDWorkaround::is_static_jfieldID(id), |
duke@435 | 144 | "to_JNIid, but not static jfieldID"); |
duke@435 | 145 | JNIid* result = (JNIid*) id; |
duke@435 | 146 | assert(result->is_static_field_id(), "to_JNIid, but not static field id"); |
duke@435 | 147 | return result; |
duke@435 | 148 | } |
duke@435 | 149 | |
duke@435 | 150 | static jfieldID to_jfieldID(instanceKlassHandle k, int offset, bool is_static) { |
duke@435 | 151 | if (is_static) { |
duke@435 | 152 | JNIid *id = k->jni_id_for(offset); |
duke@435 | 153 | debug_only(id->set_is_static_field_id()); |
duke@435 | 154 | return jfieldIDWorkaround::to_static_jfieldID(id); |
duke@435 | 155 | } else { |
duke@435 | 156 | return jfieldIDWorkaround::to_instance_jfieldID(k(), offset); |
duke@435 | 157 | } |
duke@435 | 158 | } |
duke@435 | 159 | }; |