[BUG] Memory leaks and smart pointers

[seunghwak]

In xlib/src/Graph/GraphStd.cpp

void GraphStd<vid_t, eoff_t>::COOtoCSR() {
...
247     if (_prop.is_directed_by_degree()) {
248         if (_prop.is_print())
249             std::cout << "Creating degree-directed graph ..." << std::endl;
250         eoff_t counter = 0;
251         vid_t u, v;
252         vid_t vid_small, vid_large;
253         degree_t deg_u, deg_v;
254         coo_t* coo_edges_tmp = new coo_t[_nE];
255         degree_t* _out_degrees_tmp = new degree_t[_nV]();
256         degree_t*  _in_degrees_tmp;
257         if (_structure.is_reverse())
258             _in_degrees_tmp = new degree_t[_nV]();
259         for (eoff_t i=0; i<_nE; i++) {
260             u = _coo_edges[i].first;
261             v = _coo_edges[i].second;
262             deg_u = _out_degrees[u];
263             deg_v = _out_degrees[v];
264             if ((deg_u < deg_v) || ((deg_u == deg_v) && (u < v))) {
265                 coo_edges_tmp[counter++] = {u, v};
266             }
267         }
268         _coo_edges = coo_edges_tmp;
269         _nE = counter;
270 
271         if (_structure.is_directed() && _structure.is_reverse()) {
272             for (eoff_t i = 0; i < _nE; i++) {
273                 _out_degrees_tmp[_coo_edges[i].first]++;
274                 _in_degrees_tmp[_coo_edges[i].second]++;
275             }
276         }
277         else {
278             for (eoff_t i = 0; i < _nE; i++)
279                 _out_degrees_tmp[_coo_edges[i].first]++;
280         }
281         _out_degrees = _out_degrees_tmp;
282         if (_structure.is_reverse())
283             _in_degrees = _in_degrees_tmp;
284     }
...
}

There are memory leaks in line 268, 281, and 283 (e.g. Memory pointed by _in_degrees dangles after executing _in_degrees = _in_degrees_tmp). I assume these are not the only memory leaks in the code. Using smart pointers (unique_ptr) can prevent this (e.g. if _in_degrees and _in_degrees_tmp are unique_ptr types, this is not a memory leak). We should consider replacing raw pointers with smart pointers or std:vector.

[ogreen]

We may get rid of this class (GraphStd) is it Hornet's static graph data structure and will become redundant with cuGraph and its CSR data structure.

[seunghwak]

OK, but I still think we should use unique_ptr to point allocated memory than raw pointers. This isn’t just for the GraphStd class, and unique_ptr can be much safer and unique_ptr does not incur much performance/space overhead. From: ogreen <[email protected]> Reply-To: gpuopenanalytics/graph-research <[email protected]> Date: Wednesday, January 9, 2019 at 5:51 PM To: gpuopenanalytics/graph-research <[email protected]> Cc: Seunghwa Kang <[email protected]>, Author <[email protected]> Subject: Re: [gpuopenanalytics/graph-research] [BUG] Memory leaks and smart pointers (#21) We may get rid of this class (GraphStd) is it Hornet's static graph data structure and will become redundant with cuGraph and its CSR data structure. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#21 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/Aru6kWkwwpCGd4jt4xuzXAwCiYBL_9k1ks5vBpyagaJpZM4Z4hnZ>.

…

----------------------------------------------------------------------------------- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. -----------------------------------------------------------------------------------