path: root/Source/JavaScriptCore/runtime/MachineStackMarker.cpp

/*
 *  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 "MachineStackMarker.h"

#include "Heap.h"
#include "JSArray.h"
#include "JSGlobalData.h"
#include <setjmp.h>
#include <stdlib.h>

#if OS(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 OS(WINDOWS)

#include <windows.h>
#include <malloc.h>

#elif OS(HAIKU)

#include <OS.h>

#elif OS(UNIX)

#include <stdlib.h>
#if !OS(HAIKU)
#include <sys/mman.h>
#endif
#include <unistd.h>

#if OS(SOLARIS)
#include <thread.h>
#else
#include <pthread.h>
#endif

#if HAVE(PTHREAD_NP_H)
#include <pthread_np.h>
#endif

#if OS(QNX)
#include <fcntl.h>
#include <sys/procfs.h>
#include <stdio.h>
#include <errno.h>
#endif

#endif

namespace JSC {

#if ENABLE(JSC_MULTIPLE_THREADS)

#if OS(DARWIN)
typedef mach_port_t PlatformThread;
#elif OS(WINDOWS)
typedef HANDLE PlatformThread;
#endif

class MachineStackMarker::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

MachineStackMarker::MachineStackMarker(Heap* heap)
    : m_heap(heap)
#if ENABLE(JSC_MULTIPLE_THREADS)
    , m_registeredThreads(0)
    , m_currentThreadRegistrar(0)
#endif
{
}

MachineStackMarker::~MachineStackMarker()
{
#if ENABLE(JSC_MULTIPLE_THREADS)
    if (m_currentThreadRegistrar) {
        int error = pthread_key_delete(m_currentThreadRegistrar);
        ASSERT_UNUSED(error, !error);
    }

    MutexLocker registeredThreadsLock(m_registeredThreadsMutex);
    for (Thread* t = m_registeredThreads; t;) {
        Thread* next = t->next;
        delete t;
        t = next;
    }
#endif
}

#if ENABLE(JSC_MULTIPLE_THREADS)

static inline PlatformThread getCurrentPlatformThread()
{
#if OS(DARWIN)
    return pthread_mach_thread_np(pthread_self());
#elif OS(WINDOWS)
    return pthread_getw32threadhandle_np(pthread_self());
#endif
}

void MachineStackMarker::makeUsableFromMultipleThreads()
{
    if (m_currentThreadRegistrar)
        return;

    int error = pthread_key_create(&m_currentThreadRegistrar, unregisterThread);
    if (error)
        CRASH();
}

void MachineStackMarker::registerThread()
{
    ASSERT(!m_heap->globalData()->exclusiveThread || m_heap->globalData()->exclusiveThread == currentThread());

    if (!m_currentThreadRegistrar || pthread_getspecific(m_currentThreadRegistrar))
        return;

    pthread_setspecific(m_currentThreadRegistrar, this);
    Thread* thread = new Thread(pthread_self(), getCurrentPlatformThread(), m_heap->globalData()->stack().origin());

    MutexLocker lock(m_registeredThreadsMutex);

    thread->next = m_registeredThreads;
    m_registeredThreads = thread;
}

void MachineStackMarker::unregisterThread(void* p)
{
    if (p)
        static_cast<MachineStackMarker*>(p)->unregisterThread();
}

void MachineStackMarker::unregisterThread()
{
    pthread_t currentPosixThread = pthread_self();

    MutexLocker lock(m_registeredThreadsMutex);

    if (pthread_equal(currentPosixThread, m_registeredThreads->posixThread)) {
        Thread* t = m_registeredThreads;
        m_registeredThreads = m_registeredThreads->next;
        delete t;
    } else {
        Thread* last = m_registeredThreads;
        Thread* t;
        for (t = m_registeredThreads->next; t; t = t->next) {
            if (pthread_equal(t->posixThread, currentPosixThread)) {
                last->next = t->next;
                break;
            }
            last = t;
        }
        ASSERT(t); // If t is NULL, we never found ourselves in the list.
        delete t;
    }
}

#endif

void NEVER_INLINE MachineStackMarker::markCurrentThreadConservativelyInternal(ConservativeSet& conservativeSet)
{
    m_heap->markConservatively(conservativeSet, m_heap->globalData()->stack().current(), m_heap->globalData()->stack().origin());
}

#if COMPILER(GCC)
#define REGISTER_BUFFER_ALIGNMENT __attribute__ ((aligned (sizeof(void*))))
#else
#define REGISTER_BUFFER_ALIGNMENT
#endif

void MachineStackMarker::markCurrentThreadConservatively(ConservativeSet& conservativeSet)
{
    // setjmp forces volatile registers onto the stack
    jmp_buf registers REGISTER_BUFFER_ALIGNMENT;
#if COMPILER(MSVC)
#pragma warning(push)
#pragma warning(disable: 4611)
#endif
    setjmp(registers);
#if COMPILER(MSVC)
#pragma warning(pop)
#endif

    markCurrentThreadConservativelyInternal(conservativeSet);
}

#if ENABLE(JSC_MULTIPLE_THREADS)

static inline void suspendThread(const PlatformThread& platformThread)
{
#if OS(DARWIN)
    thread_suspend(platformThread);
#elif OS(WINDOWS)
    SuspendThread(platformThread);
#else
#error Need a way to suspend threads on this platform
#endif
}

static inline void resumeThread(const PlatformThread& platformThread)
{
#if OS(DARWIN)
    thread_resume(platformThread);
#elif OS(WINDOWS)
    ResumeThread(platformThread);
#else
#error Need a way to resume threads on this platform
#endif
}

typedef unsigned long usword_t; // word size, assumed to be either 32 or 64 bit

#if OS(DARWIN)

#if CPU(X86)
typedef i386_thread_state_t PlatformThreadRegisters;
#elif CPU(X86_64)
typedef x86_thread_state64_t PlatformThreadRegisters;
#elif CPU(PPC)
typedef ppc_thread_state_t PlatformThreadRegisters;
#elif CPU(PPC64)
typedef ppc_thread_state64_t PlatformThreadRegisters;
#elif CPU(ARM)
typedef arm_thread_state_t PlatformThreadRegisters;
#else
#error Unknown Architecture
#endif

#elif OS(WINDOWS) && CPU(X86)
typedef CONTEXT PlatformThreadRegisters;
#else
#error Need a thread register struct for this platform
#endif

static size_t getPlatformThreadRegisters(const PlatformThread& platformThread, PlatformThreadRegisters& regs)
{
#if OS(DARWIN)

#if CPU(X86)
    unsigned user_count = sizeof(regs)/sizeof(int);
    thread_state_flavor_t flavor = i386_THREAD_STATE;
#elif CPU(X86_64)
    unsigned user_count = x86_THREAD_STATE64_COUNT;
    thread_state_flavor_t flavor = x86_THREAD_STATE64;
#elif CPU(PPC) 
    unsigned user_count = PPC_THREAD_STATE_COUNT;
    thread_state_flavor_t flavor = PPC_THREAD_STATE;
#elif CPU(PPC64)
    unsigned user_count = PPC_THREAD_STATE64_COUNT;
    thread_state_flavor_t flavor = PPC_THREAD_STATE64;
#elif CPU(ARM)
    unsigned user_count = ARM_THREAD_STATE_COUNT;
    thread_state_flavor_t flavor = ARM_THREAD_STATE;
#else
#error Unknown Architecture
#endif

    kern_return_t result = thread_get_state(platformThread, flavor, (thread_state_t)&regs, &user_count);
    if (result != KERN_SUCCESS) {
        WTFReportFatalError(__FILE__, __LINE__, WTF_PRETTY_FUNCTION, 
                            "JavaScript garbage collection failed because thread_get_state returned an error (%d). This is probably the result of running inside Rosetta, which is not supported.", result);
        CRASH();
    }
    return user_count * sizeof(usword_t);
// end OS(DARWIN)

#elif OS(WINDOWS) && CPU(X86)
    regs.ContextFlags = CONTEXT_INTEGER | CONTEXT_CONTROL | CONTEXT_SEGMENTS;
    GetThreadContext(platformThread, &regs);
    return sizeof(CONTEXT);
#else
#error Need a way to get thread registers on this platform
#endif
}

static inline void* otherThreadStackPointer(const PlatformThreadRegisters& regs)
{
#if OS(DARWIN)

#if __DARWIN_UNIX03

#if CPU(X86)
    return reinterpret_cast<void*>(regs.__esp);
#elif CPU(X86_64)
    return reinterpret_cast<void*>(regs.__rsp);
#elif CPU(PPC) || CPU(PPC64)
    return reinterpret_cast<void*>(regs.__r1);
#elif CPU(ARM)
    return reinterpret_cast<void*>(regs.__sp);
#else
#error Unknown Architecture
#endif

#else // !__DARWIN_UNIX03

#if CPU(X86)
    return reinterpret_cast<void*>(regs.esp);
#elif CPU(X86_64)
    return reinterpret_cast<void*>(regs.rsp);
#elif CPU(PPC) || CPU(PPC64)
    return reinterpret_cast<void*>(regs.r1);
#else
#error Unknown Architecture
#endif

#endif // __DARWIN_UNIX03

// end OS(DARWIN)
#elif CPU(X86) && OS(WINDOWS)
    return reinterpret_cast<void*>((uintptr_t) regs.Esp);
#else
#error Need a way to get the stack pointer for another thread on this platform
#endif
}

void MachineStackMarker::markOtherThreadConservatively(ConservativeSet& conservativeSet, Thread* thread)
{
    suspendThread(thread->platformThread);

    PlatformThreadRegisters regs;
    size_t regSize = getPlatformThreadRegisters(thread->platformThread, regs);

    // mark the thread's registers
    m_heap->markConservatively(conservativeSet, static_cast<void*>(&regs), static_cast<void*>(reinterpret_cast<char*>(&regs) + regSize));

    void* stackPointer = otherThreadStackPointer(regs);
    m_heap->markConservatively(conservativeSet, stackPointer, thread->stackBase);

    resumeThread(thread->platformThread);
}

#endif

void MachineStackMarker::markMachineStackConservatively(ConservativeSet& conservativeSet)
{
    markCurrentThreadConservatively(conservativeSet);

#if ENABLE(JSC_MULTIPLE_THREADS)

    if (m_currentThreadRegistrar) {

        MutexLocker lock(m_registeredThreadsMutex);

#ifndef NDEBUG
        // Forbid malloc during the mark phase. Marking a thread suspends it, so 
        // a malloc inside markChildren() would risk a deadlock with a thread that had been 
        // suspended while holding the malloc lock.
        fastMallocForbid();
#endif
        // It is safe to access the registeredThreads list, because we earlier asserted that locks are being held,
        // and since this is a shared heap, they are real locks.
        for (Thread* thread = m_registeredThreads; thread; thread = thread->next) {
            if (!pthread_equal(thread->posixThread, pthread_self()))
                markOtherThreadConservatively(conservativeSet, thread);
        }
#ifndef NDEBUG
        fastMallocAllow();
#endif
    }
#endif
}

} // namespace JSC