Mercurial > hg > truffle
annotate src/share/vm/code/oopRecorder.hpp @ 1721:413ad0331a0c
6977924: Changes for 6975078 produce build error with certain gcc versions
Summary: The changes introduced for 6975078 assign badHeapOopVal to the _allocation field in the ResourceObj class. In 32 bit linux builds with certain versions of gcc this assignment will be flagged as an error while compiling allocation.cpp. In 32 bit builds the constant value badHeapOopVal (which is cast to an intptr_t) is negative. The _allocation field is typed as an unsigned intptr_t and gcc catches this as an error.
Reviewed-by: jcoomes, ysr, phh
| author | johnc |
|---|---|
| date | Wed, 18 Aug 2010 10:59:06 -0700 |
| parents | e9ff18c4ace7 |
| children | f95d63e2154a |
| rev | line source |
|---|---|
| 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 }; |