source/Utility/SharingPtr.cpp

//===---------------------SharingPtr.cpp ------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/Utility/SharingPtr.h"

#if defined (ENABLE_SP_LOGGING)

// If ENABLE_SP_LOGGING is defined, then log all shared pointer assignements
// and allow them to be queried using a pointer by a call to:
#include <execinfo.h>
#include <map>
#include <assert.h>
#include "lldb/Host/Mutex.h"

#include <vector>

class Backtrace
{
public:
    Backtrace ();
    
    ~Backtrace ();
    
    void
    GetFrames ();
    
    void
    Dump () const;
    
private:
    void *m_sp_this;
    std::vector<void *> m_frames;
};


Backtrace::Backtrace () : m_frames()
{
}

Backtrace::~Backtrace ()
{
}

void
Backtrace::GetFrames ()
{
    void *frames[1024];
    const int count = ::backtrace (frames, sizeof(frames)/sizeof(void*));
    if (count > 2)
        m_frames.assign (frames + 2, frames + (count - 2));
}

void
Backtrace::Dump () const
{
    if (!m_frames.empty())
        ::backtrace_symbols_fd (m_frames.data(), m_frames.size(), STDOUT_FILENO);
    write (STDOUT_FILENO, "\n\n", 2);
}

extern "C" void track_sp (void *sp_this, void *ptr, long use_count)
{
    typedef std::pair<void *, Backtrace> PtrBacktracePair;
    typedef std::map<void *, PtrBacktracePair> PtrToBacktraceMap;
    static lldb_private::Mutex g_mutex(lldb_private::Mutex::eMutexTypeNormal);
    lldb_private::Mutex::Locker locker (g_mutex);
    static PtrToBacktraceMap g_map;

    if (sp_this)
    {
        printf ("sp(%p) -> %p %lu\n", sp_this, ptr, use_count);

        if (ptr)
        {
            Backtrace bt;
            bt.GetFrames();
            g_map[sp_this] = std::make_pair(ptr, bt);
        }
        else
        {
            g_map.erase (sp_this);
        }
    }
    else 
    {
        if (ptr)
            printf ("Searching for shared pointers that are tracking %p: ", ptr);
        else
            printf ("Dump all live shared pointres: ");

        uint32_t matches = 0;
        PtrToBacktraceMap::iterator pos, end = g_map.end();
        for (pos = g_map.begin(); pos != end; ++pos)
        {
            if (ptr == NULL || pos->second.first == ptr)
            {
                ++matches;
                printf ("\nsp(%p): %p\n", pos->first, pos->second.first);
                pos->second.second.Dump();
            }
        }
        if (matches == 0)
        {
            printf ("none.\n");
        }
    }
}
extern "C" void dump_sp_refs (void *ptr)
{
    // Use a specially crafted call to "track_sp" which will
    // dump info on all live shared pointers that reference "ptr"
    track_sp (NULL, ptr, 0);
}

#endif

namespace lldb_private {

namespace imp
{


    shared_count::~shared_count()
    {
    }

    void
    shared_count::add_shared()
    {
        increment(shared_owners_);
    }

    void
    shared_count::release_shared()
    {
        if (decrement(shared_owners_) == -1)
        {
            on_zero_shared();
            delete this;
        }
    }

} // imp


} // namespace lldb