Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/concurrentMarkSweep/freeChunk.hpp @ 10185:d50cc62e94ff
8012715: G1: GraphKit accesses PtrQueue::_index as int but is size_t
Summary: In graphKit INT operations were generated to access PtrQueue::_index which has type size_t. This is 64 bit on 64-bit machines. No problems occur on little endian machines as long as the index fits into 32 bit, but on big endian machines the upper part is read, which is zero. This leads to unnecessary branches to the slow path in the runtime.
Reviewed-by: twisti, johnc
Contributed-by: Martin Doerr <martin.doerr@sap.com>
| author | johnc |
|---|---|
| date | Wed, 24 Apr 2013 14:48:43 -0700 |
| parents | 685df3c6f84b |
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| rev | line source |
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| 187 | 1 /* |
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2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
| 187 | 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. |
| 187 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_FREECHUNK_HPP |
| 26 #define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_FREECHUNK_HPP | |
| 27 | |
| 28 #include "memory/allocation.hpp" | |
| 29 #include "memory/memRegion.hpp" | |
| 30 #include "oops/markOop.hpp" | |
| 31 #include "runtime/mutex.hpp" | |
| 32 #include "utilities/debug.hpp" | |
| 33 #include "utilities/globalDefinitions.hpp" | |
| 34 #include "utilities/ostream.hpp" | |
| 35 | |
| 187 | 36 // |
| 37 // Free block maintenance for Concurrent Mark Sweep Generation | |
| 38 // | |
| 39 // The main data structure for free blocks are | |
| 40 // . an indexed array of small free blocks, and | |
| 41 // . a dictionary of large free blocks | |
| 42 // | |
| 43 | |
| 44 // No virtuals in FreeChunk (don't want any vtables). | |
| 45 | |
| 46 // A FreeChunk is merely a chunk that can be in a doubly linked list | |
| 47 // and has a size field. NOTE: FreeChunks are distinguished from allocated | |
| 48 // objects in two ways (by the sweeper), depending on whether the VM is 32 or | |
| 49 // 64 bits. | |
| 50 // In 32 bits or 64 bits without CompressedOops, the second word (prev) has the | |
| 51 // LSB set to indicate a free chunk; allocated objects' klass() pointers | |
| 52 // don't have their LSB set. The corresponding bit in the CMSBitMap is | |
| 53 // set when the chunk is allocated. There are also blocks that "look free" | |
| 54 // but are not part of the free list and should not be coalesced into larger | |
| 55 // free blocks. These free blocks have their two LSB's set. | |
| 56 | |
| 57 class FreeChunk VALUE_OBJ_CLASS_SPEC { | |
| 58 friend class VMStructs; | |
| 59 // For 64 bit compressed oops, the markOop encodes both the size and the | |
| 60 // indication that this is a FreeChunk and not an object. | |
| 61 volatile size_t _size; | |
| 62 FreeChunk* _prev; | |
| 63 FreeChunk* _next; | |
| 64 | |
| 65 markOop mark() const volatile { return (markOop)_size; } | |
| 66 void set_mark(markOop m) { _size = (size_t)m; } | |
| 67 | |
| 68 public: | |
| 69 NOT_PRODUCT(static const size_t header_size();) | |
| 70 | |
| 71 // Returns "true" if the address indicates that the block represents | |
| 72 // a free chunk. | |
| 73 static bool indicatesFreeChunk(const HeapWord* addr) { | |
| 74 // Force volatile read from addr because value might change between | |
| 75 // calls. We really want the read of _mark and _prev from this pointer | |
| 76 // to be volatile but making the fields volatile causes all sorts of | |
| 77 // compilation errors. | |
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78 return ((volatile FreeChunk*)addr)->is_free(); |
| 187 | 79 } |
| 80 | |
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81 bool is_free() const volatile { |
| 187 | 82 LP64_ONLY(if (UseCompressedOops) return mark()->is_cms_free_chunk(); else) |
| 83 return (((intptr_t)_prev) & 0x1) == 0x1; | |
| 84 } | |
| 85 bool cantCoalesce() const { | |
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86 assert(is_free(), "can't get coalesce bit on not free"); |
| 187 | 87 return (((intptr_t)_prev) & 0x2) == 0x2; |
| 88 } | |
| 89 void dontCoalesce() { | |
| 90 // the block should be free | |
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91 assert(is_free(), "Should look like a free block"); |
| 187 | 92 _prev = (FreeChunk*)(((intptr_t)_prev) | 0x2); |
| 93 } | |
| 94 FreeChunk* prev() const { | |
| 95 return (FreeChunk*)(((intptr_t)_prev) & ~(0x3)); | |
| 96 } | |
| 97 | |
| 98 debug_only(void* prev_addr() const { return (void*)&_prev; }) | |
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99 debug_only(void* next_addr() const { return (void*)&_next; }) |
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100 debug_only(void* size_addr() const { return (void*)&_size; }) |
| 187 | 101 |
| 102 size_t size() const volatile { | |
| 103 LP64_ONLY(if (UseCompressedOops) return mark()->get_size(); else ) | |
| 104 return _size; | |
| 105 } | |
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106 void set_size(size_t sz) { |
| 187 | 107 LP64_ONLY(if (UseCompressedOops) set_mark(markOopDesc::set_size_and_free(sz)); else ) |
| 108 _size = sz; | |
| 109 } | |
| 110 | |
| 111 FreeChunk* next() const { return _next; } | |
| 112 | |
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113 void link_after(FreeChunk* ptr) { |
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114 link_next(ptr); |
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115 if (ptr != NULL) ptr->link_prev(this); |
| 187 | 116 } |
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117 void link_next(FreeChunk* ptr) { _next = ptr; } |
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118 void link_prev(FreeChunk* ptr) { |
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119 LP64_ONLY(if (UseCompressedOops) _prev = ptr; else) |
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120 _prev = (FreeChunk*)((intptr_t)ptr | 0x1); |
| 187 | 121 } |
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122 void clear_next() { _next = NULL; } |
| 187 | 123 void markNotFree() { |
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124 // Set _prev (klass) to null before (if) clearing the mark word below |
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125 _prev = NULL; |
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126 #ifdef _LP64 |
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127 if (UseCompressedOops) { |
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128 OrderAccess::storestore(); |
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129 set_mark(markOopDesc::prototype()); |
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130 } |
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131 #endif |
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132 assert(!is_free(), "Error"); |
| 187 | 133 } |
| 134 | |
| 135 // Return the address past the end of this chunk | |
| 6885 | 136 uintptr_t* end() const { return ((uintptr_t*) this) + size(); } |
| 187 | 137 |
| 138 // debugging | |
| 139 void verify() const PRODUCT_RETURN; | |
| 140 void verifyList() const PRODUCT_RETURN; | |
| 141 void mangleAllocated(size_t size) PRODUCT_RETURN; | |
| 142 void mangleFreed(size_t size) PRODUCT_RETURN; | |
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143 |
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144 void print_on(outputStream* st); |
| 187 | 145 }; |
| 146 | |
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147 extern size_t MinChunkSize; |
| 187 | 148 |
| 1972 | 149 |
| 150 #endif // SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_FREECHUNK_HPP |