Imported QtWebKit TP3 (git b57bc6801f1876c3220d5a4bfea33d620d477443)

Change-Id: I3b1d8a2808782c9f34d50240000e20cb38d3680f
Reviewed-by: Konstantin Tokarev <annulen@yandex.ru>

1 files changed, 127 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGSafepoint.cpp b/Source/JavaScriptCore/dfg/DFGSafepoint.cpp
new file mode 100644
index 000000000..11ba5ad9b
--- /dev/null
+++ b/Source/JavaScriptCore/dfg/DFGSafepoint.cpp
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2014 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "DFGSafepoint.h"
+
+#if ENABLE(DFG_JIT)
+
+#include "DFGPlan.h"
+#include "DFGScannable.h"
+#include "DFGThreadData.h"
+#include "JSCInlines.h"
+
+namespace JSC { namespace DFG {
+
+Safepoint::Result::~Result()
+{
+    RELEASE_ASSERT(m_wasChecked);
+}
+
+bool Safepoint::Result::didGetCancelled()
+{
+    m_wasChecked = true;
+    return m_didGetCancelled;
+}
+
+Safepoint::Safepoint(Plan& plan, Result& result)
+    : m_plan(plan)
+    , m_didCallBegin(false)
+    , m_result(result)
+{
+    RELEASE_ASSERT(result.m_wasChecked);
+    result.m_wasChecked = false;
+    result.m_didGetCancelled = false;
+}
+
+Safepoint::~Safepoint()
+{
+    RELEASE_ASSERT(m_didCallBegin);
+    if (ThreadData* data = m_plan.threadData) {
+        RELEASE_ASSERT(data->m_safepoint == this);
+        data->m_rightToRun.lock();
+        data->m_safepoint = nullptr;
+    }
+}
+
+void Safepoint::add(Scannable* scannable)
+{
+    RELEASE_ASSERT(!m_didCallBegin);
+    m_scannables.append(scannable);
+}
+
+void Safepoint::begin()
+{
+    RELEASE_ASSERT(!m_didCallBegin);
+    m_didCallBegin = true;
+    if (ThreadData* data = m_plan.threadData) {
+        RELEASE_ASSERT(!data->m_safepoint);
+        data->m_safepoint = this;
+        data->m_rightToRun.unlock();
+    }
+}
+
+void Safepoint::checkLivenessAndVisitChildren(SlotVisitor& visitor)
+{
+    RELEASE_ASSERT(m_didCallBegin);
+
+    if (m_result.m_didGetCancelled)
+        return; // We were cancelled during a previous GC!
+    
+    if (!isKnownToBeLiveDuringGC())
+        return;
+    
+    for (unsigned i = m_scannables.size(); i--;)
+        m_scannables[i]->visitChildren(visitor);
+}
+
+bool Safepoint::isKnownToBeLiveDuringGC()
+{
+    RELEASE_ASSERT(m_didCallBegin);
+    
+    if (m_result.m_didGetCancelled)
+        return true; // We were cancelled during a previous GC, so let's not mess with it this time around - pretend it's live and move on.
+    
+    return m_plan.isKnownToBeLiveDuringGC();
+}
+
+void Safepoint::cancel()
+{
+    RELEASE_ASSERT(m_didCallBegin);
+    RELEASE_ASSERT(!m_result.m_didGetCancelled); // We cannot get cancelled twice because subsequent GCs will think that we're alive and they will not do anything to us.
+    
+    m_plan.cancel();
+    m_result.m_didGetCancelled = true;
+}
+
+VM& Safepoint::vm() const
+{
+    return m_plan.vm;
+}
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)
+