Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 166 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/bytecode/ValueProfile.h b/Source/JavaScriptCore/bytecode/ValueProfile.h
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+++ b/Source/JavaScriptCore/bytecode/ValueProfile.h
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+/*
+ * Copyright (C) 2011 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.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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.
+ */
+
+#ifndef ValueProfile_h
+#define ValueProfile_h
+
+#include "JSArray.h"
+#include "PredictedType.h"
+#include "Structure.h"
+#include "WriteBarrier.h"
+
+namespace JSC {
+
+#if ENABLE(VALUE_PROFILER)
+struct ValueProfile {
+    static const unsigned logNumberOfBuckets = 0; // 1 bucket
+    static const unsigned numberOfBuckets = 1 << logNumberOfBuckets;
+    static const unsigned numberOfSpecFailBuckets = 1;
+    static const unsigned bucketIndexMask = numberOfBuckets - 1;
+    static const unsigned totalNumberOfBuckets = numberOfBuckets + numberOfSpecFailBuckets;
+    
+    ValueProfile()
+        : m_bytecodeOffset(-1)
+        , m_prediction(PredictNone)
+        , m_numberOfSamplesInPrediction(0)
+    {
+        for (unsigned i = 0; i < totalNumberOfBuckets; ++i)
+            m_buckets[i] = JSValue::encode(JSValue());
+    }
+    
+    ValueProfile(int bytecodeOffset)
+        : m_bytecodeOffset(bytecodeOffset)
+        , m_prediction(PredictNone)
+        , m_numberOfSamplesInPrediction(0)
+    {
+        for (unsigned i = 0; i < totalNumberOfBuckets; ++i)
+            m_buckets[i] = JSValue::encode(JSValue());
+    }
+    
+    EncodedJSValue* specFailBucket(unsigned i)
+    {
+        ASSERT(numberOfBuckets + i < totalNumberOfBuckets);
+        return m_buckets + numberOfBuckets + i;
+    }
+    
+    const ClassInfo* classInfo(unsigned bucket) const
+    {
+        JSValue value = JSValue::decode(m_buckets[bucket]);
+        if (!!value) {
+            if (!value.isCell())
+                return 0;
+            return value.asCell()->structure()->classInfo();
+        }
+        return 0;
+    }
+    
+    unsigned numberOfSamples() const
+    {
+        unsigned result = 0;
+        for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
+            if (!!JSValue::decode(m_buckets[i]))
+                result++;
+        }
+        return result;
+    }
+    
+    unsigned totalNumberOfSamples() const
+    {
+        return numberOfSamples() + m_numberOfSamplesInPrediction;
+    }
+    
+    bool isLive() const
+    {
+        for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
+            if (!!JSValue::decode(m_buckets[i]))
+                return true;
+        }
+        return false;
+    }
+    
+#ifndef NDEBUG
+    void dump(FILE* out)
+    {
+        fprintf(out,
+                "samples = %u, prediction = %s",
+                totalNumberOfSamples(),
+                predictionToString(m_prediction));
+        bool first = true;
+        for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
+            JSValue value = JSValue::decode(m_buckets[i]);
+            if (!!value) {
+                if (first) {
+                    fprintf(out, ": ");
+                    first = false;
+                } else
+                    fprintf(out, ", ");
+                fprintf(out, "%s", value.description());
+            }
+        }
+    }
+#endif
+    
+    // Updates the prediction and returns the new one.
+    PredictedType computeUpdatedPrediction();
+    
+    int m_bytecodeOffset; // -1 for prologue
+    
+    PredictedType m_prediction;
+    unsigned m_numberOfSamplesInPrediction;
+    
+    EncodedJSValue m_buckets[totalNumberOfBuckets];
+};
+
+inline int getValueProfileBytecodeOffset(ValueProfile* valueProfile)
+{
+    return valueProfile->m_bytecodeOffset;
+}
+
+// This is a mini value profile to catch pathologies. It is a counter that gets
+// incremented when we take the slow path on any instruction.
+struct RareCaseProfile {
+    RareCaseProfile(int bytecodeOffset)
+        : m_bytecodeOffset(bytecodeOffset)
+        , m_counter(0)
+    {
+    }
+    
+    int m_bytecodeOffset;
+    uint32_t m_counter;
+};
+
+inline int getRareCaseProfileBytecodeOffset(RareCaseProfile* rareCaseProfile)
+{
+    return rareCaseProfile->m_bytecodeOffset;
+}
+#endif
+
+}
+
+#endif
+