heap/CodeBlockSet.cpp

   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 #include "config.h"
  27 #include "CodeBlockSet.h"
  28
  29 #include "CodeBlock.h"
  30 #include "JSCInlines.h"
  31 #include "SlotVisitor.h"
  32 #include <wtf/CommaPrinter.h>
  33
  34 namespace JSC {
  35
  36 static const bool verbose = false;
  37
  38 CodeBlockSet::CodeBlockSet(BlockAllocator& blockAllocator)
  39     : m_currentlyExecuting(blockAllocator)
  40 {
  41 }
  42
  43 CodeBlockSet::~CodeBlockSet()
  44 {
  45     for (CodeBlock* codeBlock : m_oldCodeBlocks)
  46         codeBlock->deref();
  47
  48     for (CodeBlock* codeBlock : m_newCodeBlocks)
  49         codeBlock->deref();
  50 }
  51
  52 void CodeBlockSet::add(PassRefPtr<CodeBlock> codeBlock)
  53 {
  54     CodeBlock* block = codeBlock.leakRef();
  55     bool isNewEntry = m_newCodeBlocks.add(block).isNewEntry;
  56     ASSERT_UNUSED(isNewEntry, isNewEntry);
  57 }
  58
  59 void CodeBlockSet::promoteYoungCodeBlocks()
  60 {
  61     m_oldCodeBlocks.add(m_newCodeBlocks.begin(), m_newCodeBlocks.end());
  62     m_newCodeBlocks.clear();
  63 }
  64
  65 void CodeBlockSet::clearMarksForFullCollection()
  66 {
  67     for (CodeBlock* codeBlock : m_oldCodeBlocks) {
  68         codeBlock->m_mayBeExecuting = false;
  69         codeBlock->m_visitAggregateHasBeenCalled = false;
  70     }
  71
  72     // We promote after we clear marks on the old generation CodeBlocks because
  73     // none of the young generations CodeBlocks need to be cleared.
  74     promoteYoungCodeBlocks();
  75 }
  76
  77 void CodeBlockSet::clearMarksForEdenCollection(const Vector<const JSCell*>& rememberedSet)
  78 {
  79     // This ensures that we will revisit CodeBlocks in remembered Executables even if they were previously marked.
  80     for (const JSCell* cell : rememberedSet) {
  81         ScriptExecutable* executable = const_cast<ScriptExecutable*>(jsDynamicCast<const ScriptExecutable*>(cell));
  82         if (!executable)
  83             continue;
  84         executable->forEachCodeBlock([](CodeBlock* codeBlock) {
  85             codeBlock->m_mayBeExecuting = false;
  86             codeBlock->m_visitAggregateHasBeenCalled = false;
  87         });
  88     }
  89 }
  90
  91 void CodeBlockSet::deleteUnmarkedAndUnreferenced(HeapOperation collectionType)
  92 {
  93     HashSet<CodeBlock*>& set = collectionType == EdenCollection ? m_newCodeBlocks : m_oldCodeBlocks;
  94
  95     // This needs to be a fixpoint because code blocks that are unmarked may
  96     // refer to each other. For example, a DFG code block that is owned by
  97     // the GC may refer to an FTL for-entry code block that is also owned by
  98     // the GC.
  99     Vector<CodeBlock*, 16> toRemove;
 100     if (verbose)
 101         dataLog("Fixpointing over unmarked, set size = ", set.size(), "...\n");
 102     for (;;) {
 103         for (CodeBlock* codeBlock : set) {
 104             if (!codeBlock->hasOneRef())
 105                 continue;
 106             if (codeBlock->m_mayBeExecuting)
 107                 continue;
 108             codeBlock->deref();
 109             toRemove.append(codeBlock);
 110         }
 111         if (verbose)
 112             dataLog("    Removing ", toRemove.size(), " blocks.\n");
 113         if (toRemove.isEmpty())
 114             break;
 115         for (CodeBlock* codeBlock : toRemove)
 116             set.remove(codeBlock);
 117         toRemove.resize(0);
 118     }
 119
 120     // Any remaining young CodeBlocks are live and need to be promoted to the set of old CodeBlocks.
 121     if (collectionType == EdenCollection)
 122         promoteYoungCodeBlocks();
 123 }
 124
 125 void CodeBlockSet::remove(CodeBlock* codeBlock)
 126 {
 127     codeBlock->deref();
 128     if (m_oldCodeBlocks.contains(codeBlock)) {
 129         m_oldCodeBlocks.remove(codeBlock);
 130         return;
 131     }
 132     ASSERT(m_newCodeBlocks.contains(codeBlock));
 133     m_newCodeBlocks.remove(codeBlock);
 134 }
 135
 136 void CodeBlockSet::traceMarked(SlotVisitor& visitor)
 137 {
 138     if (verbose)
 139         dataLog("Tracing ", m_currentlyExecuting.size(), " code blocks.\n");
 140     for (CodeBlock* codeBlock : m_currentlyExecuting) {
 141         ASSERT(codeBlock->m_mayBeExecuting);
 142         codeBlock->visitAggregate(visitor);
 143     }
 144 }
 145
 146 void CodeBlockSet::rememberCurrentlyExecutingCodeBlocks(Heap* heap)
 147 {
 148 #if ENABLE(GGC)
 149     if (verbose)
 150         dataLog("Remembering ", m_currentlyExecuting.size(), " code blocks.\n");
 151     for (CodeBlock* codeBlock : m_currentlyExecuting) {
 152         heap->addToRememberedSet(codeBlock->ownerExecutable());
 153         ASSERT(codeBlock->m_mayBeExecuting);
 154     }
 155     m_currentlyExecuting.clear();
 156 #else
 157     UNUSED_PARAM(heap);
 158 #endif // ENABLE(GGC)
 159 }
 160
 161 void CodeBlockSet::dump(PrintStream& out) const
 162 {
 163     CommaPrinter comma;
 164     out.print("{old = [");
 165     for (CodeBlock* codeBlock : m_oldCodeBlocks)
 166         out.print(comma, pointerDump(codeBlock));
 167     out.print("], new = [");
 168     comma = CommaPrinter();
 169     for (CodeBlock* codeBlock : m_newCodeBlocks)
 170         out.print(comma, pointerDump(codeBlock));
 171     out.print("], currentlyExecuting = [");
 172     comma = CommaPrinter();
 173     for (CodeBlock* codeBlock : m_currentlyExecuting)
 174         out.print(comma, pointerDump(codeBlock));
 175     out.print("]}");
 176 }
 177
 178 } // namespace JSC
 179