SharingPtr.cpp revision 314564 
1//===---------------------SharingPtr.cpp ------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "lldb/Utility/SharingPtr.h"
11
12#if defined(ENABLE_SP_LOGGING)
13
14// If ENABLE_SP_LOGGING is defined, then log all shared pointer assignments
15// and allow them to be queried using a pointer by a call to:
16#include <assert.h>
17#include <execinfo.h>
18
19#include "llvm/ADT/STLExtras.h"
20
21#include <map>
22#include <mutex>
23#include <vector>
24
25class Backtrace {
26public:
27  Backtrace();
28
29  ~Backtrace();
30
31  void GetFrames();
32
33  void Dump() const;
34
35private:
36  void *m_sp_this;
37  std::vector<void *> m_frames;
38};
39
40Backtrace::Backtrace() : m_frames() {}
41
42Backtrace::~Backtrace() {}
43
44void Backtrace::GetFrames() {
45  void *frames[1024];
46  const int count = ::backtrace(frames, llvm::array_lengthof(frames));
47  if (count > 2)
48    m_frames.assign(frames + 2, frames + (count - 2));
49}
50
51void Backtrace::Dump() const {
52  if (!m_frames.empty())
53    ::backtrace_symbols_fd(m_frames.data(), m_frames.size(), STDOUT_FILENO);
54  write(STDOUT_FILENO, "\n\n", 2);
55}
56
57extern "C" void track_sp(void *sp_this, void *ptr, long use_count) {
58  typedef std::pair<void *, Backtrace> PtrBacktracePair;
59  typedef std::map<void *, PtrBacktracePair> PtrToBacktraceMap;
60  static std::mutex g_mutex;
61  std::lock_guard<std::mutex> guard(g_mutex);
62  static PtrToBacktraceMap g_map;
63
64  if (sp_this) {
65    printf("sp(%p) -> %p %lu\n", sp_this, ptr, use_count);
66
67    if (ptr) {
68      Backtrace bt;
69      bt.GetFrames();
70      g_map[sp_this] = std::make_pair(ptr, bt);
71    } else {
72      g_map.erase(sp_this);
73    }
74  } else {
75    if (ptr)
76      printf("Searching for shared pointers that are tracking %p: ", ptr);
77    else
78      printf("Dump all live shared pointres: ");
79
80    uint32_t matches = 0;
81    PtrToBacktraceMap::iterator pos, end = g_map.end();
82    for (pos = g_map.begin(); pos != end; ++pos) {
83      if (ptr == NULL || pos->second.first == ptr) {
84        ++matches;
85        printf("\nsp(%p): %p\n", pos->first, pos->second.first);
86        pos->second.second.Dump();
87      }
88    }
89    if (matches == 0) {
90      printf("none.\n");
91    }
92  }
93}
94// Put dump_sp_refs in the lldb namespace to it gets through our exports lists
95// filter in the LLDB.framework or lldb.so
96namespace lldb {
97
98void dump_sp_refs(void *ptr) {
99  // Use a specially crafted call to "track_sp" which will
100  // dump info on all live shared pointers that reference "ptr"
101  track_sp(NULL, ptr, 0);
102}
103}
104
105#endif
106
107namespace lldb_private {
108
109namespace imp {
110
111shared_count::~shared_count() {}
112
113void shared_count::add_shared() {
114#ifdef _MSC_VER
115  _InterlockedIncrement(&shared_owners_);
116#else
117  ++shared_owners_;
118#endif
119}
120
121void shared_count::release_shared() {
122#ifdef _MSC_VER
123  if (_InterlockedDecrement(&shared_owners_) == -1)
124#else
125  if (--shared_owners_ == -1)
126#endif
127  {
128    on_zero_shared();
129    delete this;
130  }
131}
132
133} // imp
134
135} // namespace lldb
136