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src/share/vm/runtime/jfieldIDWorkaround.hpp@2a33b32dd03c (annotated)

src/share/vm/runtime/jfieldIDWorkaround.hpp

Thu, 24 May 2018 19:24:53 +0800

author
aoqi
date
Thu, 24 May 2018 19:24:53 +0800
changeset 8861
2a33b32dd03c
parent 6876
710a3c8b516e
permissions
-rw-r--r--

#7046 Disable the compilation when branch offset is beyond short branch
Contributed-by: fujie, aoqi

aoqi@0 1 /*
aoqi@0 2 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0 4 *
aoqi@0 5 * This code is free software; you can redistribute it and/or modify it
aoqi@0 6 * under the terms of the GNU General Public License version 2 only, as
aoqi@0 7 * published by the Free Software Foundation.
aoqi@0 8 *
aoqi@0 9 * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0 12 * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0 13 * accompanied this code).
aoqi@0 14 *
aoqi@0 15 * You should have received a copy of the GNU General Public License version
aoqi@0 16 * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0 18 *
aoqi@0 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0 20 * or visit www.oracle.com if you need additional information or have any
aoqi@0 21 * questions.
aoqi@0 22 *
aoqi@0 23 */
aoqi@0 24
aoqi@0 25 #ifndef SHARE_VM_RUNTIME_JFIELDIDWORKAROUND_HPP
aoqi@0 26 #define SHARE_VM_RUNTIME_JFIELDIDWORKAROUND_HPP
aoqi@0 27
aoqi@0 28 class jfieldIDWorkaround: AllStatic {
aoqi@0 29 // This workaround is because JVMTI doesn't have distinct entry points
aoqi@0 30 // for methods that use static jfieldIDs and instance jfieldIDs.
aoqi@0 31 // The workaround is to steal a low-order bit:
aoqi@0 32 // a 1 means the jfieldID is an instance jfieldID,
aoqi@0 33 // and the rest of the word is the offset of the field.
aoqi@0 34 // a 0 means the jfieldID is a static jfieldID,
aoqi@0 35 // and the rest of the word is the JNIid*.
aoqi@0 36 //
aoqi@0 37 // Another low-order bit is used to mark if an instance field
aoqi@0 38 // is accompanied by an indication of which class it applies to.
aoqi@0 39 //
aoqi@0 40 // Bit-format of a jfieldID (most significant first):
aoqi@0 41 // address:30 instance=0:1 checked=0:1
aoqi@0 42 // offset:30 instance=1:1 checked=0:1
aoqi@0 43 // klass:23 offset:7 instance=1:1 checked=1:1
aoqi@0 44 //
aoqi@0 45 // If the offset does not fit in 7 bits, or if the fieldID is
aoqi@0 46 // not checked, then the checked bit is zero and the rest of
aoqi@0 47 // the word (30 bits) contains only the offset.
aoqi@0 48 //
aoqi@0 49 private:
aoqi@0 50 enum {
aoqi@0 51 checked_bits = 1,
aoqi@0 52 instance_bits = 1,
aoqi@0 53 address_bits = BitsPerWord - checked_bits - instance_bits,
aoqi@0 54
aoqi@0 55 large_offset_bits = address_bits, // unioned with address
aoqi@0 56 small_offset_bits = 7,
aoqi@0 57 klass_bits = address_bits - small_offset_bits,
aoqi@0 58
aoqi@0 59 checked_shift = 0,
aoqi@0 60 instance_shift = checked_shift + checked_bits,
aoqi@0 61 address_shift = instance_shift + instance_bits,
aoqi@0 62
aoqi@0 63 offset_shift = address_shift, // unioned with address
aoqi@0 64 klass_shift = offset_shift + small_offset_bits,
aoqi@0 65
aoqi@0 66 checked_mask_in_place = right_n_bits(checked_bits) << checked_shift,
aoqi@0 67 instance_mask_in_place = right_n_bits(instance_bits) << instance_shift,
aoqi@0 68 #ifndef _WIN64
aoqi@0 69 large_offset_mask = right_n_bits(large_offset_bits),
aoqi@0 70 small_offset_mask = right_n_bits(small_offset_bits),
aoqi@0 71 klass_mask = right_n_bits(klass_bits)
aoqi@0 72 #endif
aoqi@0 73 };
aoqi@0 74
aoqi@0 75 #ifdef _WIN64
aoqi@0 76 // These values are too big for Win64
aoqi@0 77 const static uintptr_t large_offset_mask = right_n_bits(large_offset_bits);
aoqi@0 78 const static uintptr_t small_offset_mask = right_n_bits(small_offset_bits);
aoqi@0 79 const static uintptr_t klass_mask = right_n_bits(klass_bits);
aoqi@0 80 #endif
aoqi@0 81
aoqi@0 82 // helper routines:
aoqi@0 83 static bool is_checked_jfieldID(jfieldID id) {
aoqi@0 84 uintptr_t as_uint = (uintptr_t) id;
aoqi@0 85 return ((as_uint & checked_mask_in_place) != 0);
aoqi@0 86 }
aoqi@0 87 static intptr_t raw_instance_offset(jfieldID id) {
aoqi@0 88 uintptr_t result = (uintptr_t) id >> address_shift;
aoqi@0 89 if (VerifyJNIFields && is_checked_jfieldID(id)) {
aoqi@0 90 result &= small_offset_mask; // cut off the hash bits
aoqi@0 91 }
aoqi@0 92 return (intptr_t)result;
aoqi@0 93 }
aoqi@0 94 static intptr_t encode_klass_hash(Klass* k, intptr_t offset);
aoqi@0 95 static bool klass_hash_ok(Klass* k, jfieldID id);
aoqi@0 96 static void verify_instance_jfieldID(Klass* k, jfieldID id);
aoqi@0 97
aoqi@0 98 public:
aoqi@0 99 static bool is_valid_jfieldID(Klass* k, jfieldID id);
aoqi@0 100
aoqi@0 101 static bool is_instance_jfieldID(Klass* k, jfieldID id) {
aoqi@0 102 uintptr_t as_uint = (uintptr_t) id;
aoqi@0 103 return ((as_uint & instance_mask_in_place) != 0);
aoqi@0 104 }
aoqi@0 105 static bool is_static_jfieldID(jfieldID id) {
aoqi@0 106 uintptr_t as_uint = (uintptr_t) id;
aoqi@0 107 return ((as_uint & instance_mask_in_place) == 0);
aoqi@0 108 }
aoqi@0 109
aoqi@0 110 static jfieldID to_instance_jfieldID(Klass* k, int offset) {
aoqi@0 111 intptr_t as_uint = ((offset & large_offset_mask) << offset_shift) | instance_mask_in_place;
aoqi@0 112 if (VerifyJNIFields) {
aoqi@0 113 as_uint |= encode_klass_hash(k, offset);
aoqi@0 114 }
aoqi@0 115 jfieldID result = (jfieldID) as_uint;
aoqi@0 116 #ifndef ASSERT
aoqi@0 117 // always verify in debug mode; switchable in anything else
aoqi@0 118 if (VerifyJNIFields)
aoqi@0 119 #endif // ASSERT
aoqi@0 120 {
aoqi@0 121 verify_instance_jfieldID(k, result);
aoqi@0 122 }
aoqi@0 123 assert(raw_instance_offset(result) == (offset & large_offset_mask), "extract right offset");
aoqi@0 124 return result;
aoqi@0 125 }
aoqi@0 126
aoqi@0 127 static intptr_t from_instance_jfieldID(Klass* k, jfieldID id) {
aoqi@0 128 #ifndef ASSERT
aoqi@0 129 // always verify in debug mode; switchable in anything else
aoqi@0 130 if (VerifyJNIFields)
aoqi@0 131 #endif // ASSERT
aoqi@0 132 {
aoqi@0 133 verify_instance_jfieldID(k, id);
aoqi@0 134 }
aoqi@0 135 return raw_instance_offset(id);
aoqi@0 136 }
aoqi@0 137
aoqi@0 138 static jfieldID to_static_jfieldID(JNIid* id) {
aoqi@0 139 assert(id->is_static_field_id(), "from_JNIid, but not static field id");
aoqi@0 140 jfieldID result = (jfieldID) id;
aoqi@0 141 assert(from_static_jfieldID(result) == id, "must produce the same static id");
aoqi@0 142 return result;
aoqi@0 143 }
aoqi@0 144
aoqi@0 145 static JNIid* from_static_jfieldID(jfieldID id) {
aoqi@0 146 assert(jfieldIDWorkaround::is_static_jfieldID(id),
aoqi@0 147 "to_JNIid, but not static jfieldID");
aoqi@0 148 JNIid* result = (JNIid*) id;
aoqi@0 149 assert(result->is_static_field_id(), "to_JNIid, but not static field id");
aoqi@0 150 return result;
aoqi@0 151 }
aoqi@0 152
aoqi@0 153 static jfieldID to_jfieldID(instanceKlassHandle k, int offset, bool is_static) {
aoqi@0 154 if (is_static) {
aoqi@0 155 JNIid *id = k->jni_id_for(offset);
aoqi@0 156 debug_only(id->set_is_static_field_id());
aoqi@0 157 return jfieldIDWorkaround::to_static_jfieldID(id);
aoqi@0 158 } else {
aoqi@0 159 return jfieldIDWorkaround::to_instance_jfieldID(k(), offset);
aoqi@0 160 }
aoqi@0 161 }
aoqi@0 162 };
aoqi@0 163
aoqi@0 164 #endif // SHARE_VM_RUNTIME_JFIELDIDWORKAROUND_HPP

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