heap/CodeBlockSet.h

   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
  37 namespace JSC {
  38
  39 class CodeBlock;
  40 class Heap;
  41 class JSCell;
  42 class SlotVisitor;
  43
  44 // CodeBlockSet tracks all CodeBlocks. Every CodeBlock starts out with one
  45 // reference coming in from GC. The GC is responsible for freeing CodeBlocks
  46 // once they hasOneRef() and nobody is running code from that CodeBlock.
  47
  48 class CodeBlockSet {
  49     WTF_MAKE_NONCOPYABLE(CodeBlockSet);
  50
  51 public:
  52     CodeBlockSet();
  53     ~CodeBlockSet();
  54
  55     // Add a CodeBlock. This is only called by CodeBlock constructors.
  56     void add(PassRefPtr<CodeBlock>);
  57
  58     // Clear mark bits for certain CodeBlocks depending on the type of collection.
  59     void clearMarksForEdenCollection(const Vector<const JSCell*>&);
  60
  61     // Clear all mark bits for all CodeBlocks.
  62     void clearMarksForFullCollection();
  63
  64     // Mark a pointer that may be a CodeBlock that belongs to the set of DFG
  65     // blocks. This is defined in CodeBlock.h.
  66     void mark(CodeBlock* candidateCodeBlock);
  67     void mark(void* candidateCodeBlock);
  68
  69     // Delete all code blocks that are only referenced by this set (i.e. owned
  70     // by this set), and that have not been marked.
  71     void deleteUnmarkedAndUnreferenced(HeapOperation);
  72
  73     void remove(CodeBlock*);
  74
  75     // Trace all marked code blocks. The CodeBlock is free to make use of
  76     // mayBeExecuting.
  77     void traceMarked(SlotVisitor&);
  78
  79     // Add all currently executing CodeBlocks to the remembered set to be
  80     // re-scanned during the next collection.
  81     void rememberCurrentlyExecutingCodeBlocks(Heap*);
  82
  83     // Visits each CodeBlock in the heap until the visitor function returns true
  84     // to indicate that it is done iterating, or until every CodeBlock has been
  85     // visited.
  86     template<typename Functor> void iterate(Functor& functor)
  87     {
  88         for (auto& codeBlock : m_oldCodeBlocks) {
  89             bool done = functor(codeBlock);
  90             if (done)
  91                 return;
  92         }
  93
  94         for (auto& codeBlock : m_newCodeBlocks) {
  95             bool done = functor(codeBlock);
  96             if (done)
  97                 return;
  98         }
  99     }
 100
 101     void dump(PrintStream&) const;
 102
 103 private:
 104     void clearMarksForCodeBlocksInRememberedExecutables(const Vector<const JSCell*>&);
 105     void promoteYoungCodeBlocks();
 106
 107     // This is not a set of RefPtr<CodeBlock> because we need to be able to find
 108     // arbitrary bogus pointers. I could have written a thingy that had peek types
 109     // and all, but that seemed like overkill.
 110     HashSet<CodeBlock*> m_oldCodeBlocks;
 111     HashSet<CodeBlock*> m_newCodeBlocks;
 112     Vector<CodeBlock*> m_currentlyExecuting;
 113 };
 114
 115 } // namespace JSC
 116
 117 #endif // CodeBlockSet_h
 118