1/* 2 * Copyright (C) 2013, 2014 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#ifndef CodeBlockSet_h 27#define CodeBlockSet_h 28 29#include "GCSegmentedArray.h" 30#include "HeapOperation.h" 31#include <wtf/HashSet.h> 32#include <wtf/Noncopyable.h> 33#include <wtf/PassRefPtr.h> 34#include <wtf/PrintStream.h> 35#include <wtf/RefPtr.h> 36 37namespace JSC { 38 39class BlockAllocator; 40class CodeBlock; 41class Heap; 42class JSCell; 43class SlotVisitor; 44 45// CodeBlockSet tracks all CodeBlocks. Every CodeBlock starts out with one 46// reference coming in from GC. The GC is responsible for freeing CodeBlocks 47// once they hasOneRef() and nobody is running code from that CodeBlock. 48 49class CodeBlockSet { 50 WTF_MAKE_NONCOPYABLE(CodeBlockSet); 51 52public: 53 CodeBlockSet(BlockAllocator&); 54 ~CodeBlockSet(); 55 56 // Add a CodeBlock. This is only called by CodeBlock constructors. 57 void add(PassRefPtr<CodeBlock>); 58 59 // Clear mark bits for certain CodeBlocks depending on the type of collection. 60 void clearMarksForEdenCollection(const Vector<const JSCell*>&); 61 62 // Clear all mark bits for all CodeBlocks. 63 void clearMarksForFullCollection(); 64 65 // Mark a pointer that may be a CodeBlock that belongs to the set of DFG 66 // blocks. This is defined in CodeBlock.h. 67 void mark(CodeBlock* candidateCodeBlock); 68 void mark(void* candidateCodeBlock); 69 70 // Delete all code blocks that are only referenced by this set (i.e. owned 71 // by this set), and that have not been marked. 72 void deleteUnmarkedAndUnreferenced(HeapOperation); 73 74 void remove(CodeBlock*); 75 76 // Trace all marked code blocks. The CodeBlock is free to make use of 77 // mayBeExecuting. 78 void traceMarked(SlotVisitor&); 79 80 // Add all currently executing CodeBlocks to the remembered set to be 81 // re-scanned during the next collection. 82 void rememberCurrentlyExecutingCodeBlocks(Heap*); 83 84 // Visits each CodeBlock in the heap until the visitor function returns true 85 // to indicate that it is done iterating, or until every CodeBlock has been 86 // visited. 87 template<typename Functor> void iterate(Functor& functor) 88 { 89 for (auto& codeBlock : m_oldCodeBlocks) { 90 bool done = functor(codeBlock); 91 if (done) 92 return; 93 } 94 95 for (auto& codeBlock : m_newCodeBlocks) { 96 bool done = functor(codeBlock); 97 if (done) 98 return; 99 } 100 } 101 102 void dump(PrintStream&) const; 103 104private: 105 void clearMarksForCodeBlocksInRememberedExecutables(const Vector<const JSCell*>&); 106 void promoteYoungCodeBlocks(); 107 108 // This is not a set of RefPtr<CodeBlock> because we need to be able to find 109 // arbitrary bogus pointers. I could have written a thingy that had peek types 110 // and all, but that seemed like overkill. 111 HashSet<CodeBlock*> m_oldCodeBlocks; 112 HashSet<CodeBlock*> m_newCodeBlocks; 113 GCSegmentedArray<CodeBlock*> m_currentlyExecuting; 114}; 115 116} // namespace JSC 117 118#endif // CodeBlockSet_h 119 120