/*

 *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.

 *  Copyright (C) 2007 Eric Seidel <eric@webkit.org>

 *

 *  This library is free software; you can redistribute it and/or

 *  modify it under the terms of the GNU Lesser General Public

 *  License as published by the Free Software Foundation; either

 *  version 2 of the License, or (at your option) any later version.

 *

 *  This library is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 *  Lesser General Public License for more details.

 *

 *  You should have received a copy of the GNU Lesser General Public

 *  License along with this library; if not, write to the Free Software

 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 *

 */

#include "config.h"

#include "Collector.h"

#include "ArgList.h"

#include "CallFrame.h"

#include "CodeBlock.h"

#include "CollectorHeapIterator.h"

#include "Interpreter.h"

#include "JSArray.h"

#include "JSGlobalObject.h"

#include "JSLock.h"

#include "JSONObject.h"

#include "JSString.h"

#include "JSValue.h"

#include "MarkStack.h"

#include "Nodes.h"

#include "Tracing.h"

#include <algorithm>

#include <limits.h>

#include <setjmp.h>

#include <stdlib.h>

#include <wtf/FastMalloc.h>

#include <wtf/HashCountedSet.h>

#include <wtf/UnusedParam.h>

#include <wtf/VMTags.h>

#if PLATFORM(DARWIN)

#include <mach/mach_init.h>

#include <mach/mach_port.h>

#include <mach/task.h>

#include <mach/thread_act.h>

#include <mach/vm_map.h>

#elif PLATFORM(WIN_OS)

#include <windows.h>

#include <malloc.h>

#elif PLATFORM(HAIKU)

#include <OS.h>

#elif PLATFORM(UNIX)

#include <stdlib.h>

#if !PLATFORM(HAIKU)

#include <sys/mman.h>

#endif

#include <unistd.h>

#if defined(QT_LINUXBASE)

#include <dlfcn.h>

#endif

#if defined(__UCLIBC__)

// versions of uClibc 0.9.28 and below do not have

// pthread_getattr_np or pthread_attr_getstack.

#if __UCLIBC_MAJOR__ == 0 && \

    (__UCLIBC_MINOR__ < 9 || \

    (__UCLIBC_MINOR__ == 9 && __UCLIBC_SUBLEVEL__ <= 30))

#define UCLIBC_USE_PROC_SELF_MAPS 1

#include <stdio_ext.h>

extern int *__libc_stack_end;

#endif

#endif

#if PLATFORM(SOLARIS)

#include <thread.h>

#else

#include <pthread.h>

#endif

#if HAVE(PTHREAD_NP_H)

#include <pthread_np.h>

#endif

#if PLATFORM(QNX)

#include <fcntl.h>

#include <sys/procfs.h>

#include <stdio.h>

#include <errno.h>

#endif

#endif

#define COLLECT_ON_EVERY_ALLOCATION 0

using std::max;

namespace JSC {

// tunable parameters

const size_t GROWTH_FACTOR = 2;

const size_t LOW_WATER_FACTOR = 4;

const size_t ALLOCATIONS_PER_COLLECTION = 4000;

// This value has to be a macro to be used in max() without introducing

// a PIC branch in Mach-O binaries, see <rdar://problem/5971391>.

#define MIN_ARRAY_SIZE (static_cast<size_t>(14))

#if ENABLE(JSC_MULTIPLE_THREADS)

#if PLATFORM(DARWIN)

typedef mach_port_t PlatformThread;

#elif PLATFORM(WIN_OS)

struct PlatformThread {

    PlatformThread(DWORD _id, HANDLE _handle) : id(_id), handle(_handle) {}

    DWORD id;

    HANDLE handle;

};

#endif

class Heap::Thread {

public:

    Thread(pthread_t pthread, const PlatformThread& platThread, void* base) 

        : posixThread(pthread)

        , platformThread(platThread)

        , stackBase(base)

    {

    }

    Thread* next;

    pthread_t posixThread;

    PlatformThread platformThread;

    void* stackBase;

};

#endif

Heap::Heap(JSGlobalData* globalData)

    : m_markListSet(0)

#if ENABLE(JSC_MULTIPLE_THREADS)

    , m_registeredThreads(0)

    , m_currentThreadRegistrar(0)

#endif

    , m_globalData(globalData)

{

    ASSERT(globalData);

    memset(&primaryHeap, 0, sizeof(CollectorHeap));

    memset(&numberHeap, 0, sizeof(CollectorHeap));

}

Heap::~Heap()

{

    // The destroy function must already have been called, so assert this.

    ASSERT(!m_globalData);

}

void Heap::destroy()

{

    JSLock lock(SilenceAssertionsOnly);

    if (!m_globalData)

        return;

    // The global object is not GC protected at this point, so sweeping may delete it

    // (and thus the global data) before other objects that may use the global data.

    RefPtr<JSGlobalData> protect(m_globalData);

    delete m_markListSet;

    m_markListSet = 0;

    sweep<PrimaryHeap>();

    // No need to sweep number heap, because the JSNumber destructor doesn't do anything.

    ASSERT(!primaryHeap.numLiveObjects);

    freeBlocks(&primaryHeap);

    freeBlocks(&numberHeap);

#if ENABLE(JSC_MULTIPLE_THREADS)

    if (m_currentThreadRegistrar) {

        int error = pthread_key_delete(m_currentThreadRegistrar);

        ASSERT_UNUSED(error, !error);

    }

    MutexLocker registeredThreadsLock(m_registeredThreadsMutex);

    for (Heap::Thread* t = m_registeredThreads; t;) {

        Heap::Thread* next = t->next;

        delete t;

        t = next;

    }

#endif

    m_globalData = 0;

}

template <HeapType heapType>

NEVER_INLINE CollectorBlock* Heap::allocateBlock()

{

    // Disable the use of vm_map for the Qt build on Darwin, because when compiled on 10.4

    // it crashes on 10.5

#if PLATFORM(DARWIN) && !PLATFORM(QT)

    vm_address_t address = 0;

    // FIXME: tag the region as a JavaScriptCore heap when we get a registered VM tag: <rdar://problem/6054788>.

    vm_map(current_task(), &address, BLOCK_SIZE, BLOCK_OFFSET_MASK, VM_FLAGS_ANYWHERE | VM_TAG_FOR_COLLECTOR_MEMORY, MEMORY_OBJECT_NULL, 0, FALSE, VM_PROT_DEFAULT, VM_PROT_DEFAULT, VM_INHERIT_DEFAULT);

#elif PLATFORM(SYMBIAN)

        CRASH();

    memset(reinterpret_cast<void*>(address), 0, BLOCK_SIZE);

#elif PLATFORM(WINCE)

    void* address = VirtualAlloc(NULL, BLOCK_SIZE, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);

#elif PLATFORM(WIN_OS)

#if COMPILER(MINGW)

    void* address = __mingw_aligned_malloc(BLOCK_SIZE, BLOCK_SIZE);

#else

    void* address = _aligned_malloc(BLOCK_SIZE, BLOCK_SIZE);

#endif

    memset(address, 0, BLOCK_SIZE);

#elif HAVE(POSIX_MEMALIGN)

    void* address;

    posix_memalign(&address, BLOCK_SIZE, BLOCK_SIZE);

    memset(address, 0, BLOCK_SIZE);

#else

#if ENABLE(JSC_MULTIPLE_THREADS)

#error Need to initialize pagesize safely.

#endif

    static size_t pagesize = getpagesize();

    size_t extra = 0;

    if (BLOCK_SIZE > pagesize)

        extra = BLOCK_SIZE - pagesize;

    void* mmapResult = mmap(NULL, BLOCK_SIZE + extra, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);

    uintptr_t address = reinterpret_cast<uintptr_t>(mmapResult);

    size_t adjust = 0;

    if ((address & BLOCK_OFFSET_MASK) != 0)

        adjust = BLOCK_SIZE - (address & BLOCK_OFFSET_MASK);

    if (adjust > 0)

        munmap(reinterpret_cast<char*>(address), adjust);

    if (adjust < extra)

        munmap(reinterpret_cast<char*>(address + adjust + BLOCK_SIZE), extra - adjust);

    address += adjust;

    memset(reinterpret_cast<void*>(address), 0, BLOCK_SIZE);

#endif

    CollectorBlock* block = reinterpret_cast<CollectorBlock*>(address);

    block->freeList = block->cells;

    block->heap = this;

    block->type = heapType;

    CollectorHeap& heap = heapType == PrimaryHeap ? primaryHeap : numberHeap;

    size_t numBlocks = heap.numBlocks;

    if (heap.usedBlocks == numBlocks) {

        static const size_t maxNumBlocks = ULONG_MAX / sizeof(CollectorBlock*) / GROWTH_FACTOR;

        if (numBlocks > maxNumBlocks)

            CRASH();

        numBlocks = max(MIN_ARRAY_SIZE, numBlocks * GROWTH_FACTOR);

        heap.numBlocks = numBlocks;

        heap.blocks = static_cast<CollectorBlock**>(fastRealloc(heap.blocks, numBlocks * sizeof(CollectorBlock*)));

    }

    heap.blocks[heap.usedBlocks++] = block;

    return block;

}

template <HeapType heapType>

NEVER_INLINE void Heap::freeBlock(size_t block)

{

    CollectorHeap& heap = heapType == PrimaryHeap ? primaryHeap : numberHeap;

    freeBlock(heap.blocks[block]);

    // swap with the last block so we compact as we go

    heap.blocks[block] = heap.blocks[heap.usedBlocks - 1];

    heap.usedBlocks--;

    if (heap.numBlocks > MIN_ARRAY_SIZE && heap.usedBlocks < heap.numBlocks / LOW_WATER_FACTOR) {

        heap.numBlocks = heap.numBlocks / GROWTH_FACTOR; 

        heap.blocks = static_cast<CollectorBlock**>(fastRealloc(heap.blocks, heap.numBlocks * sizeof(CollectorBlock*)));

    }

}

NEVER_INLINE void Heap::freeBlock(CollectorBlock* block)

{

    // Disable the use of vm_deallocate for the Qt build on Darwin, because when compiled on 10.4

    // it crashes on 10.5

#if PLATFORM(DARWIN) && !PLATFORM(QT)

    vm_deallocate(current_task(), reinterpret_cast<vm_address_t>(block), BLOCK_SIZE);

#elif PLATFORM(SYMBIAN)

#elif PLATFORM(WINCE)

    VirtualFree(block, 0, MEM_RELEASE);

#elif PLATFORM(WIN_OS)

#if COMPILER(MINGW)

    __mingw_aligned_free(block);

#else

    _aligned_free(block);

#endif

#elif HAVE(POSIX_MEMALIGN)

    free(block);

#else

    munmap(reinterpret_cast<char*>(block), BLOCK_SIZE);

#endif

}

void Heap::freeBlocks(CollectorHeap* heap)

{

    for (size_t i = 0; i < heap->usedBlocks; ++i)

        if (heap->blocks[i])

            freeBlock(heap->blocks[i]);

    fastFree(heap->blocks);

    memset(heap, 0, sizeof(CollectorHeap));

}

void Heap::recordExtraCost(size_t cost)

{

    // Our frequency of garbage collection tries to balance memory use against speed

    // by collecting based on the number of newly created values. However, for values

    // that hold on to a great deal of memory that's not in the form of other JS values,

    // that is not good enough - in some cases a lot of those objects can pile up and

    // use crazy amounts of memory without a GC happening. So we track these extra

    // memory costs. Only unusually large objects are noted, and we only keep track

    // of this extra cost until the next GC. In garbage collected languages, most values

    // are either very short lived temporaries, or have extremely long lifetimes. So

    // if a large value survives one garbage collection, there is not much point to

    // collecting more frequently as long as it stays alive.

    // NOTE: we target the primaryHeap unconditionally as JSNumber doesn't modify cost 

    primaryHeap.extraCost += cost;

}

template <HeapType heapType> ALWAYS_INLINE void* Heap::heapAllocate(size_t s)

{

    typedef typename HeapConstants<heapType>::Block Block;

    typedef typename HeapConstants<heapType>::Cell Cell;

    CollectorHeap& heap = heapType == PrimaryHeap ? primaryHeap : numberHeap;

    ASSERT(JSLock::lockCount() > 0);

    ASSERT(JSLock::currentThreadIsHoldingLock());

    ASSERT_UNUSED(s, s <= HeapConstants<heapType>::cellSize);

    ASSERT(heap.operationInProgress == NoOperation);

    ASSERT(heapType == PrimaryHeap || heap.extraCost == 0);

    // FIXME: If another global variable access here doesn't hurt performance

    // too much, we could CRASH() in NDEBUG builds, which could help ensure we

    // don't spend any time debugging cases where we allocate inside an object's

    // deallocation code.

#if COLLECT_ON_EVERY_ALLOCATION

    collect();

#endif

    size_t numLiveObjects = heap.numLiveObjects;

    size_t usedBlocks = heap.usedBlocks;

    size_t i = heap.firstBlockWithPossibleSpace;

    // if we have a huge amount of extra cost, we'll try to collect even if we still have

    // free cells left.

    if (heapType == PrimaryHeap && heap.extraCost > ALLOCATIONS_PER_COLLECTION) {

        size_t numLiveObjectsAtLastCollect = heap.numLiveObjectsAtLastCollect;

        size_t numNewObjects = numLiveObjects - numLiveObjectsAtLastCollect;

        const size_t newCost = numNewObjects + heap.extraCost;

        if (newCost >= ALLOCATIONS_PER_COLLECTION && newCost >= numLiveObjectsAtLastCollect)

            goto collect;

    }

    ASSERT(heap.operationInProgress == NoOperation);

#ifndef NDEBUG

    // FIXME: Consider doing this in NDEBUG builds too (see comment above).

    heap.operationInProgress = Allocation;

#endif

scan:

    Block* targetBlock;

    size_t targetBlockUsedCells;

    if (i != usedBlocks) {

        targetBlock = reinterpret_cast<Block*>(heap.blocks[i]);

        targetBlockUsedCells = targetBlock->usedCells;

        ASSERT(targetBlockUsedCells <= HeapConstants<heapType>::cellsPerBlock);

        while (targetBlockUsedCells == HeapConstants<heapType>::cellsPerBlock) {

            if (++i == usedBlocks)

                goto collect;

            targetBlock = reinterpret_cast<Block*>(heap.blocks[i]);

            targetBlockUsedCells = targetBlock->usedCells;

            ASSERT(targetBlockUsedCells <= HeapConstants<heapType>::cellsPerBlock);

        }

        heap.firstBlockWithPossibleSpace = i;

    } else {

collect:

        size_t numLiveObjectsAtLastCollect = heap.numLiveObjectsAtLastCollect;

        size_t numNewObjects = numLiveObjects - numLiveObjectsAtLastCollect;

        const size_t newCost = numNewObjects + heap.extraCost;

        if (newCost >= ALLOCATIONS_PER_COLLECTION && newCost >= numLiveObjectsAtLastCollect) {

#ifndef NDEBUG

            heap.operationInProgress = NoOperation;

#endif

            bool foundGarbage = collect();

            numLiveObjects = heap.numLiveObjects;

            usedBlocks = heap.usedBlocks;

            i = heap.firstBlockWithPossibleSpace;

#ifndef NDEBUG

            heap.operationInProgress = Allocation;

#endif

            if (foundGarbage)

                goto scan;

        }

        // didn't find a block, and GC didn't reclaim anything, need to allocate a new block

        targetBlock = reinterpret_cast<Block*>(allocateBlock<heapType>());

        heap.firstBlockWithPossibleSpace = heap.usedBlocks - 1;

        targetBlockUsedCells = 0;

    }

    // find a free spot in the block and detach it from the free list

    Cell* newCell = targetBlock->freeList;

    // "next" field is a cell offset -- 0 means next cell, so a zeroed block is already initialized

    targetBlock->freeList = (newCell + 1) + newCell->u.freeCell.next;

    targetBlock->usedCells = static_cast<uint32_t>(targetBlockUsedCells + 1);

    heap.numLiveObjects = numLiveObjects + 1;

#ifndef NDEBUG

    // FIXME: Consider doing this in NDEBUG builds too (see comment above).

    heap.operationInProgress = NoOperation;

#endif

    return newCell;

}

void* Heap::allocate(size_t s)

{

    return heapAllocate<PrimaryHeap>(s);

}

void* Heap::allocateNumber(size_t s)

{

    return heapAllocate<NumberHeap>(s);

}

#if PLATFORM(WINCE)

void* g_stackBase = 0;

inline bool isPageWritable(void* page)

{

    MEMORY_BASIC_INFORMATION memoryInformation;

    DWORD result = VirtualQuery(page, &memoryInformation, sizeof(memoryInformation));

    // return false on error, including ptr outside memory

    if (result != sizeof(memoryInformation))

        return false;

    DWORD protect = memoryInformation.Protect & ~(PAGE_GUARD | PAGE_NOCACHE);

    return protect == PAGE_READWRITE

        || protect == PAGE_WRITECOPY

        || protect == PAGE_EXECUTE_READWRITE

        || protect == PAGE_EXECUTE_WRITECOPY;

}

static void* getStackBase(void* previousFrame)

{

    // find the address of this stack frame by taking the address of a local variable

    bool isGrowingDownward;

    void* thisFrame = (void*)(&isGrowingDownward);

    isGrowingDownward = previousFrame < &thisFrame;

    static DWORD pageSize = 0;

    if (!pageSize) {

        SYSTEM_INFO systemInfo;

        GetSystemInfo(&systemInfo);

        pageSize = systemInfo.dwPageSize;

    }

    // scan all of memory starting from this frame, and return the last writeable page found

    register char* currentPage = (char*)((DWORD)thisFrame & ~(pageSize - 1));

    if (isGrowingDownward) {

        while (currentPage > 0) {

            // check for underflow

            if (currentPage >= (char*)pageSize)

                currentPage -= pageSize;

            else

                currentPage = 0;

            if (!isPageWritable(currentPage))

                return currentPage + pageSize;

        }

        return 0;

    } else {

        while (true) {

            // guaranteed to complete because isPageWritable returns false at end of memory

            currentPage += pageSize;

            if (!isPageWritable(currentPage))

                return currentPage;

        }

    }

}

#endif

#if PLATFORM(QNX)

static inline void *currentThreadStackBaseQNX()

{

    static void* stackBase = 0;

    static size_t stackSize = 0;