2011-02-11  Siddharth Mathur  <siddharth.mathur@nokia.com>

        Reviewed by NOBODY (OOPS!).

        [Symbian] OSAllocator implementation for Symbian OS. 

        Manages both data and code region requests. V8 and Sunspider work nicely with JSC interpreter.

        Not tested with JSC JIT yet as it has unrelated failures. Also no thread safety yet.   

        https://bugs.webkit.org/show_bug.cgi?id=51128

        * JavaScriptCore.pri: removed HAL linkage

        * wtf/Bitmap.h:

        (WTF::::findRunOfZeros): find run of zeros in a bitmap. quick n dirty

        * wtf/OSAllocator.h:

        (WTF::OSAllocator::decommitAndRelease): decommit explicitly 

        * wtf/OSAllocatorSymbian.cpp: Impl. of OSAllocator interface 

        (WTF::allocateCodeChunk): utility for code chunks

        (WTF::deallocateCodeChunk): utility for code chunks

        (WTF::dataAllocatorInstance): getter for data allocator instance

        (WTF::OSAllocator::reserveUncommitted):

        (WTF::OSAllocator::releaseDecommitted):

        (WTF::OSAllocator::commit):

        (WTF::OSAllocator::decommit):

        (WTF::OSAllocator::reserveAndCommit):

        (WTF::PageAllocatorSymbian::PageAllocatorSymbian): piggybacks multiple requests on 1 Symbian chunk

        (WTF::PageAllocatorSymbian::~PageAllocatorSymbian):

        (WTF::PageAllocatorSymbian::reserve):

        (WTF::PageAllocatorSymbian::release):

        (WTF::PageAllocatorSymbian::commit):

        (WTF::PageAllocatorSymbian::decommit):

        (WTF::PageAllocatorSymbian::contains):

        * wtf/PageAllocatorSymbian.h: Added.

        (WTF::ChunkWithMetadata::ChunkWithMetadata): wrapper around RChunk  

        (WTF::ChunkWithMetadata::~ChunkWithMetadata):

        (WTF::ChunkWithMetadata::contains):

    int64_t findRunOfZeros(size_t) const;

inline int64_t Bitmap<size>::findRunOfZeros(size_t runLength) const

{

    if (!runLength) 

            runLength = 1; 

    for (size_t i = 0; i <= (size - runLength) ; i++) {

        bool found = true; 

        for (size_t j = i; j <= (i + runLength - 1) ; j++) { 

            if (get(j)) {

                found = false; 

                break;

            }

        }

        if (found)  

            return i; 

    }

    return -1;

}

template<size_t size>

 * Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

    if (dataAllocatorInstance()->contains(parkedBase)) 

        dataAllocatorInstance()->release(parkedBase, bytes);

    // NOOP for code chunks (JIT) because we released them in decommit()

    // For code chunks, we commit (early) in reserveUncommitted(), so NOOP

    // For data regions, do real work

    if (!executable) 

        dataAllocatorInstance()->commit(address, bytes);

}

void OSAllocator::decommit(void* address, size_t bytes) 

{ 

    if (dataAllocatorInstance()->contains(address))

        dataAllocatorInstance()->decommit(address, bytes);

    else

        deallocateCodeChunk(address); // for code chunk, decommit AND release    

}

void* OSAllocator::reserveAndCommit(size_t bytes, Usage usage, bool writable, bool executable)

{ 

    void* base = reserveUncommitted(bytes, usage, writable, executable);

    commit(base, bytes, writable, executable);

    return base;

}

// The PageAllocatorSymbian class helps map OSAllocator calls for reserve/commit/decommit

// to a single large Symbian chunk. Only works with multiples of page size, and as a corollary 

// all addresses accepted or returned by it are also page-sized aligned. 

// Design notes: 

// - We initialize a chunk up-front with a large reservation size

// - The entire reservation reserve is logically divided into pageSized blocks (4K on Symbian) 

// - The map maintains 1 bit for each of the 4K-sized region in our address space

// - OSAllocator::reserveUncommitted() requests lead to 1 or more bits being set in map 

//   to indicate internally reserved state. The VM address corresponding to the first bit is returned. 

// - OSAllocator::commit() actually calls RChunk.commit() and commits *all or part* of the region 

//   reserved via reserveUncommitted() previously. 

// - OSAllocator::decommit() calls RChunk.decommit() 

// - OSAllocator::releaseDecommitted() unparks all the bits in the map, but trusts that a previously

//   call to decommit() would have returned the memory to the OS 

PageAllocatorSymbian::PageAllocatorSymbian()

{        

    __ASSERT_ALWAYS(m_pageSize == WTF::pageSize(), User::Panic(KErrorStringPageSize, m_pageSize));

    RChunk chunk;

    TInt error = chunk.CreateDisconnectedLocal(0, 0, TInt(largeReservationSize));

    __ASSERT_ALWAYS(error == KErrNone, User::Panic(KErrorStringChunkCreation, error));

    m_chunkWithMeta = new ChunkWithMetadata(chunk.Handle()); // takes ownership of chunk

}

PageAllocatorSymbian::~PageAllocatorSymbian() 

{

    delete m_chunkWithMeta;

}

// Reserves a region internally in the bitmap

void* PageAllocatorSymbian::reserve(size_t bytes) 

{ 

    // Find first available region

    const size_t nPages = bytes / m_pageSize;

    const int64_t startIdx = m_map.findRunOfZeros(nPages);

    // Pseudo OOM

    if (startIdx < 0)

        return 0;

    for (size_t i = startIdx; i < startIdx + nPages ; i++)

        m_map.set(i);

    return static_cast<void*>( m_chunkWithMeta->m_base + (TUint)(m_pageSize * startIdx) ); 

}

// Reverses the effects of a reserve() call

void PageAllocatorSymbian::release(void* address, size_t bytes)

{

    const size_t startIdx = (static_cast<char*>(address) - m_chunkWithMeta->m_base) / m_pageSize;

    const size_t nPages = bytes / m_pageSize;

    for (size_t i = startIdx; i < startIdx + nPages ; i++)

        m_map.clear(i);

}

// Actually commit memory from the OS, after a previous call to reserve()

bool PageAllocatorSymbian::commit(void* address, size_t bytes) 

{ 

    // sanity check that bits were previously set

    const size_t idx = (static_cast<char*>(address) - m_chunkWithMeta->m_base) / m_pageSize;

    const size_t nPages = bytes / m_pageSize;

    __ASSERT_ALWAYS(m_map.get(idx), User::Panic(KErrorStringInternalConsistency, idx));

    __ASSERT_ALWAYS(m_map.get(idx+nPages-1), User::Panic(KErrorStringInternalConsistency, idx+nPages-1));

    TInt error = m_chunkWithMeta->Commit(static_cast<char*>(address) - m_chunkWithMeta->m_base, bytes);

    return (error == KErrNone);

}

// Inverse operation of commit(), a release() should follow later

bool PageAllocatorSymbian::decommit(void* address, size_t bytes) 

{ 

    TInt error = m_chunkWithMeta->Decommit(static_cast<char*>(address) - m_chunkWithMeta->m_base, bytes);

    return (error == KErrNone); 

/*

 * Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies)

 *

 * 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 PageAllocatorSymbian_h

#define PageAllocatorSymbian_h

#include <e32std.h>

#include <wtf/BitMap.h>

namespace WTF { 

size_t pageSize();

// Convenience wrapper around an RChunk

class ChunkWithMetadata : public RChunk {

public:   

    ChunkWithMetadata(TInt handle) 

    {

        SetHandle(handle);

        // prevent kernel calls by caching these

        m_base = reinterpret_cast<char*>(Base()); 

        m_maxSize = MaxSize();

    }

    ~ChunkWithMetadata() 

    { 

        Decommit(0, m_maxSize);

        Close();

    }

    // checks if address is in chunk's virtual address space

    bool contains(const void* address) const 

    {

        return (static_cast<const char*>(address) >= m_base && static_cast<const char*>(address) < (m_base + m_maxSize));  

    }

    char* m_base; 

    size_t m_maxSize; 

};

// Size of the large up-front reservation

#if defined(__WINS__) 

// Emulator has limited virtual address space

const size_t largeReservationSize = 96*1024*1024;

#else

// HW has plenty of virtual addresses

const size_t largeReservationSize = 256*1024*1024;

#endif

class PageAllocatorSymbian { 

public:     

    PageAllocatorSymbian();

    ~PageAllocatorSymbian();

    void* reserve(size_t);

    void release(void*, size_t);

    bool commit(void*, size_t);

    bool decommit(void*, size_t);

    bool contains(const void*) const; 

private:     

    static const size_t m_pageSize = 4096; 

    ChunkWithMetadata* m_chunkWithMeta; 

    Bitmap<largeReservationSize / m_pageSize> m_map;

};

} // namespace WTF

#endif // PageAllocatorSymbian_h