Mercurial > hg > truffle
annotate src/share/vm/code/oopRecorder.hpp @ 1579:e9ff18c4ace7
Merge
| author | jrose |
|---|---|
| date | Wed, 02 Jun 2010 22:45:42 -0700 |
| parents | c18cbe5936b8 1a5913bf5e19 |
| children | f95d63e2154a |
| rev | line source |
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| 0 | 1 /* |
| 1579 | 2 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 // Recording and retrieval of oop relocations in compiled code. | |
| 26 | |
| 27 class CodeBlob; | |
| 28 | |
| 29 class OopRecorder : public ResourceObj { | |
| 30 public: | |
| 31 // A two-way mapping from positive indexes to oop handles. | |
| 32 // The zero index is reserved for a constant (sharable) null. | |
| 33 // Indexes may not be negative. | |
| 34 | |
| 35 // Use the given arena to manage storage, if not NULL. | |
| 36 // By default, uses the current ResourceArea. | |
| 37 OopRecorder(Arena* arena = NULL); | |
| 38 | |
| 39 // Generate a new index on which CodeBlob::oop_addr_at will work. | |
| 40 // allocate_index and find_index never return the same index, | |
| 41 // and allocate_index never returns the same index twice. | |
| 42 // In fact, two successive calls to allocate_index return successive ints. | |
| 43 int allocate_index(jobject h) { | |
| 44 return add_handle(h, false); | |
| 45 } | |
| 46 | |
| 47 // For a given jobject, this will return the same index repeatedly. | |
| 48 // The index can later be given to oop_at to retrieve the oop. | |
| 49 // However, the oop must not be changed via CodeBlob::oop_addr_at. | |
| 50 int find_index(jobject h) { | |
| 51 int index = maybe_find_index(h); | |
| 52 if (index < 0) { // previously unallocated | |
| 53 index = add_handle(h, true); | |
| 54 } | |
| 55 return index; | |
| 56 } | |
| 57 | |
| 58 // variant of find_index which does not allocate if not found (yields -1) | |
| 59 int maybe_find_index(jobject h); | |
| 60 | |
| 61 // returns the size of the generated oop table, for sizing the CodeBlob. | |
| 62 // must be called after all oops are allocated! | |
| 63 int oop_size(); | |
| 64 | |
| 65 // Retrieve the oop handle at a given index. | |
| 66 jobject handle_at(int index); | |
| 67 | |
| 68 int element_count() { | |
| 69 // there is always a NULL virtually present as first object | |
| 70 return _handles->length() + first_index; | |
| 71 } | |
| 72 | |
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73 // copy the generated oop table to nmethod |
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74 void copy_to(nmethod* nm); // => nm->copy_oops(_handles) |
| 0 | 75 |
| 76 bool is_unused() { return _handles == NULL && !_complete; } | |
| 77 #ifdef ASSERT | |
| 78 bool is_complete() { return _complete; } | |
| 79 #endif | |
| 80 | |
| 81 private: | |
| 82 // leaky hash table of handle => index, to help detect duplicate insertion | |
| 83 class IndexCache: public ResourceObj { | |
| 84 // This class is only used by the OopRecorder class. | |
| 85 friend class OopRecorder; | |
| 86 enum { | |
| 87 _log_cache_size = 9, | |
| 88 _cache_size = (1<<_log_cache_size), | |
| 89 // Index entries are ints. The LSBit is a collision indicator. | |
| 90 _collision_bit_shift = 0, | |
| 91 _collision_bit = 1, | |
| 92 _index_shift = _collision_bit_shift+1 | |
| 93 }; | |
| 94 int _cache[_cache_size]; | |
| 95 static juint cache_index(jobject handle) { | |
| 96 juint ci = (int) (intptr_t) handle; | |
| 97 ci ^= ci >> (BitsPerByte*2); | |
| 98 ci += ci >> (BitsPerByte*1); | |
| 99 return ci & (_cache_size-1); | |
| 100 } | |
| 101 int* cache_location(jobject handle) { | |
| 102 return &_cache[ cache_index(handle) ]; | |
| 103 } | |
| 104 static bool cache_location_collision(int* cloc) { | |
| 105 return ((*cloc) & _collision_bit) != 0; | |
| 106 } | |
| 107 static int cache_location_index(int* cloc) { | |
| 108 return (*cloc) >> _index_shift; | |
| 109 } | |
| 110 static void set_cache_location_index(int* cloc, int index) { | |
| 111 int cval0 = (*cloc); | |
| 112 int cval1 = (index << _index_shift); | |
| 113 if (cval0 != 0 && cval1 != cval0) cval1 += _collision_bit; | |
| 114 (*cloc) = cval1; | |
| 115 } | |
| 116 IndexCache(); | |
| 117 }; | |
| 118 | |
| 119 // Helper function; returns false for NULL or Universe::non_oop_word(). | |
| 120 inline bool is_real_jobject(jobject h); | |
| 121 | |
| 122 void maybe_initialize(); | |
| 123 int add_handle(jobject h, bool make_findable); | |
| 124 | |
| 125 enum { null_index = 0, first_index = 1, index_cache_threshold = 20 }; | |
| 126 | |
| 127 GrowableArray<jobject>* _handles; // ordered list (first is always NULL) | |
| 128 GrowableArray<int>* _no_finds; // all unfindable indexes; usually empty | |
| 129 IndexCache* _indexes; // map: jobject -> its probable index | |
| 130 Arena* _arena; | |
| 131 bool _complete; | |
| 132 | |
| 133 #ifdef ASSERT | |
| 134 static int _find_index_calls, _hit_indexes, _missed_indexes; | |
| 135 #endif | |
| 136 }; |