/*

 * Copyright (C) 2008 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 SamplingTool_h

#define SamplingTool_h

#include <wtf/Assertions.h>

#include <wtf/HashMap.h>

#include <wtf/Threading.h>

#include "Nodes.h"

#include "Opcode.h"

namespace JSC {

    class ScriptExecutable;

    class SamplingFlags {

        friend class JIT;

    public:

        static void start();

        static void stop();

#if ENABLE(SAMPLING_FLAGS)

        static void setFlag(unsigned flag)

        {

            ASSERT(flag >= 1);

            ASSERT(flag <= 32);

            s_flags |= 1u << (flag - 1);

        }

        static void clearFlag(unsigned flag)

        {

            ASSERT(flag >= 1);

            ASSERT(flag <= 32);

            s_flags &= ~(1u << (flag - 1));

        }

        static void sample();

        class ScopedFlag {

        public:

            ScopedFlag(int flag)

                : m_flag(flag)

            {

                setFlag(flag);

            }

            ~ScopedFlag()

            {

                clearFlag(m_flag);

            }

        private:

            int m_flag;

        };

#endif

    private:

        static uint32_t s_flags;

#if ENABLE(SAMPLING_FLAGS)

        static uint64_t s_flagCounts[33];

#endif

    };

    class CodeBlock;

    class ExecState;

    class Interpreter;

    class ScopeNode;

    struct Instruction;

    struct ScriptSampleRecord {

        ScriptSampleRecord(ScriptExecutable* executable)

            : m_executable(executable)

            , m_codeBlock(0)

            , m_sampleCount(0)

            , m_opcodeSampleCount(0)

            , m_samples(0)

            , m_size(0)

        {

        }

        ~ScriptSampleRecord()

        {

            if (m_samples)

                free(m_samples);

        }

        void sample(CodeBlock*, Instruction*);

        RefPtr<ScriptExecutable> m_executable;

        CodeBlock* m_codeBlock;

        int m_sampleCount;

        int m_opcodeSampleCount;

        int* m_samples;

        unsigned m_size;

    };

    typedef WTF::HashMap<ScriptExecutable*, ScriptSampleRecord*> ScriptSampleRecordMap;

    class SamplingThread {

    public:

        // Sampling thread state.

        static bool s_running;

        static unsigned s_hertz;

        static ThreadIdentifier s_samplingThread;

        static void start(unsigned hertz=10000);

        static void stop();

        static void* threadStartFunc(void*);

    };

    class SamplingTool {

    public:

        friend struct CallRecord;

        friend class HostCallRecord;

#if ENABLE(OPCODE_SAMPLING)

        class CallRecord : public Noncopyable {

        public:

            CallRecord(SamplingTool* samplingTool)

                : m_samplingTool(samplingTool)

                , m_savedSample(samplingTool->m_sample)

                , m_savedCodeBlock(samplingTool->m_codeBlock)

            {

            }

            ~CallRecord()

            {

                m_samplingTool->m_sample = m_savedSample;

                m_samplingTool->m_codeBlock = m_savedCodeBlock;

            }

        private:

            SamplingTool* m_samplingTool;

            intptr_t m_savedSample;

            CodeBlock* m_savedCodeBlock;

        };

        class HostCallRecord : public CallRecord {

        public:

            HostCallRecord(SamplingTool* samplingTool)

                : CallRecord(samplingTool)

            {

                samplingTool->m_sample |= 0x1;

            }

        };

#else

        class CallRecord : public Noncopyable {

        public:

            CallRecord(SamplingTool*)

            {

            }

        };

        class HostCallRecord : public CallRecord {

        public:

            HostCallRecord(SamplingTool* samplingTool)

                : CallRecord(samplingTool)

            {

            }

        };

#endif        

        SamplingTool(Interpreter* interpreter)

            : m_interpreter(interpreter)

            , m_codeBlock(0)

            , m_sample(0)

            , m_sampleCount(0)

            , m_opcodeSampleCount(0)

#if ENABLE(CODEBLOCK_SAMPLING)

            , m_scopeSampleMap(new ScriptSampleRecordMap())

#endif

        {

            memset(m_opcodeSamples, 0, sizeof(m_opcodeSamples));

            memset(m_opcodeSamplesInCTIFunctions, 0, sizeof(m_opcodeSamplesInCTIFunctions));

        }

        ~SamplingTool()

        {

#if ENABLE(CODEBLOCK_SAMPLING)

            deleteAllValues(*m_scopeSampleMap);

#endif

        }

        void setup();

        void dump(ExecState*);

        void notifyOfScope(ScriptExecutable* scope);

        void sample(CodeBlock* codeBlock, Instruction* vPC)

        {

            ASSERT(!(reinterpret_cast<intptr_t>(vPC) & 0x3));

            m_codeBlock = codeBlock;

            m_sample = reinterpret_cast<intptr_t>(vPC);

        }

        CodeBlock** codeBlockSlot() { return &m_codeBlock; }

        intptr_t* sampleSlot() { return &m_sample; }

        void* encodeSample(Instruction* vPC, bool inCTIFunction = false, bool inHostFunction = false)

        {

            ASSERT(!(reinterpret_cast<intptr_t>(vPC) & 0x3));

            return reinterpret_cast<void*>(reinterpret_cast<intptr_t>(vPC) | (static_cast<intptr_t>(inCTIFunction) << 1) | static_cast<intptr_t>(inHostFunction));

        }

        static void sample();

    private:

        class Sample {

        public:

            Sample(volatile intptr_t sample, CodeBlock* volatile codeBlock)

                : m_sample(sample)

                , m_codeBlock(codeBlock)

            {

            }

            bool isNull() { return !m_sample; }

            CodeBlock* codeBlock() { return m_codeBlock; }

            Instruction* vPC() { return reinterpret_cast<Instruction*>(m_sample & ~0x3); }

            bool inHostFunction() { return m_sample & 0x1; }

            bool inCTIFunction() { return m_sample & 0x2; }

        private:

            intptr_t m_sample;

            CodeBlock* m_codeBlock;

        };

        void doRun();

        static SamplingTool* s_samplingTool;

        Interpreter* m_interpreter;

        // State tracked by the main thread, used by the sampling thread.

        CodeBlock* m_codeBlock;

        intptr_t m_sample;

        // Gathered sample data.

        long long m_sampleCount;

        long long m_opcodeSampleCount;

        unsigned m_opcodeSamples[numOpcodeIDs];

        unsigned m_opcodeSamplesInCTIFunctions[numOpcodeIDs];

#if ENABLE(CODEBLOCK_SAMPLING)

        Mutex m_scriptSampleMapMutex;

        OwnPtr<ScriptSampleRecordMap> m_scopeSampleMap;

#endif

    };

    // AbstractSamplingCounter:

    //

    // Implements a named set of counters, printed on exit if ENABLE(SAMPLING_COUNTERS).

    // See subclasses below, SamplingCounter, GlobalSamplingCounter and DeletableSamplingCounter.

    class AbstractSamplingCounter {

        friend class JIT;

        friend class DeletableSamplingCounter;

    public:

        void count(uint32_t count = 1)

        {

            m_counter += count;

        }

        static void dump();

    protected:

        // Effectively the contructor, however called lazily in the case of GlobalSamplingCounter.

        void init(const char* name)

        {

            m_counter = 0;

            m_name = name;

            // Set m_next to point to the head of the chain, and inform whatever is

            // currently at the head that this node will now hold the pointer to it.

            m_next = s_abstractSamplingCounterChain;

            s_abstractSamplingCounterChain->m_referer = &m_next;

            // Add this node to the head of the list.

            s_abstractSamplingCounterChain = this;

            m_referer = &s_abstractSamplingCounterChain;

        }

        int64_t m_counter;

        const char* m_name;

        AbstractSamplingCounter* m_next;

        // This is a pointer to the pointer to this node in the chain; used to

        // allow fast linked list deletion.

        AbstractSamplingCounter** m_referer;

        // Null object used to detect end of static chain.

        static AbstractSamplingCounter s_abstractSamplingCounterChainEnd;

        static AbstractSamplingCounter* s_abstractSamplingCounterChain;

        static bool s_completed;

    };

#if ENABLE(SAMPLING_COUNTERS)

    // SamplingCounter:

    //

    // This class is suitable and (hopefully!) convenient for cases where a counter is

    // required within the scope of a single function.  It can be instantiated as a

    // static variable since it contains a constructor but not a destructor (static

    // variables in WebKit cannot have destructors).

    //

    // For example:

    //

    // void someFunction()

    // {

    //     static SamplingCounter countMe("This is my counter.  There are many like it, but this one is mine.");

    //     countMe.count();

    //     // ...

    // }

    //

    class SamplingCounter : public AbstractSamplingCounter {

    public:

        SamplingCounter(const char* name) { init(name); }

    };

    // GlobalSamplingCounter:

    //

    // This class is suitable for use where a counter is to be declared globally,

    // since it contains neither a constructor nor destructor.  Instead, ensure

    // that 'name()' is called to provide the counter with a name (and also to

    // allow it to be printed out on exit).

    //

    // GlobalSamplingCounter globalCounter;

    //

    // void firstFunction()

    // {

    //     // Put this within a function that is definitely called!

    //     // (Or alternatively alongside all calls to 'count()').

    //     globalCounter.name("I Name You Destroyer.");

    //     globalCounter.count();

    //     // ...

    // }

    //

    // void secondFunction()

    // {

    //     globalCounter.count();

    //     // ...

    // }

    //

    class GlobalSamplingCounter : public AbstractSamplingCounter {

    public:

        void name(const char* name)

        {

            // Global objects should be mapped in zero filled memory, so this should

            // be a safe (albeit not necessarily threadsafe) check for 'first call'.

            if (!m_next)

                init(name);

        }

    };

    // DeletableSamplingCounter:

    //

    // The above classes (SamplingCounter, GlobalSamplingCounter), are intended for

    // use within a global or static scope, and as such cannot have a destructor.

    // This means there is no convenient way for them to remove themselves from the

    // static list of counters, and should an instance of either class be freed

    // before 'dump()' has walked over the list it will potentially walk over an

    // invalid pointer.

    //

    // This class is intended for use where the counter may possibly be deleted before

    // the program exits.  Should this occur, the counter will print it's value to

    // stderr, and remove itself from the static list.  Example:

    //

    // DeletableSamplingCounter* counter = new DeletableSamplingCounter("The Counter With No Name");

    // counter->count();

    // delete counter;

    //

    class DeletableSamplingCounter : public AbstractSamplingCounter {

    public:

        DeletableSamplingCounter(const char* name) { init(name); }

        ~DeletableSamplingCounter()

        {

            if (!s_completed)

                fprintf(stderr, "DeletableSamplingCounter \"%s\" deleted early (with count %lld)\n", m_name, m_counter);

            // Our m_referer pointer should know where the pointer to this node is,

            // and m_next should know that this node is the previous node in the list.

            ASSERT(*m_referer == this);

            ASSERT(m_next->m_referer == &m_next);

            // Remove this node from the list, and inform m_next that we have done so.

            m_next->m_referer = m_referer;

            *m_referer = m_next;

        }

    };

#endif

} // namespace JSC

#endif // SamplingTool_h