summaryrefslogtreecommitdiff
path: root/indra/llcommon/llcoros.cpp
blob: 20340397db8823aa54ebbdbac64fbc98570751c6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
/**
 * @file   llcoros.cpp
 * @author Nat Goodspeed
 * @date   2009-06-03
 * @brief  Implementation for llcoros.
 *
 * $LicenseInfo:firstyear=2009&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * 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;
 * version 2.1 of the License only.
 *
 * 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
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llwin32headers.h"

// Precompiled header
#include "linden_common.h"
// associated header
#include "llcoros.h"
// STL headers
// std headers
#include <atomic>
#include <stdexcept>
// external library headers
#include <boost/bind.hpp>
#include <boost/fiber/fiber.hpp>
#ifndef BOOST_DISABLE_ASSERTS
#define UNDO_BOOST_DISABLE_ASSERTS
// with Boost 1.65.1, needed for Mac with this specific header
#define BOOST_DISABLE_ASSERTS
#endif
#include <boost/fiber/protected_fixedsize_stack.hpp>
#ifdef UNDO_BOOST_DISABLE_ASSERTS
#undef UNDO_BOOST_DISABLE_ASSERTS
#undef BOOST_DISABLE_ASSERTS
#endif
// other Linden headers
#include "llapp.h"
#include "lltimer.h"
#include "llevents.h"
#include "llerror.h"
#include "stringize.h"
#include "llexception.h"

#if LL_WINDOWS
#include <excpt.h>
#endif

// static
LLCoros::CoroData& LLCoros::get_CoroData(const std::string& caller)
{
    CoroData* current{ nullptr };
    // be careful about attempted accesses in the final throes of app shutdown
    if (! wasDeleted())
    {
        current = instance().mCurrent.get();
    }
    // For the main() coroutine, the one NOT explicitly launched by launch(),
    // we never explicitly set mCurrent. Use a static CoroData instance with
    // canonical values.
    if (! current)
    {
        static std::atomic<int> which_thread(0);
        // Use alternate CoroData constructor.
        static thread_local CoroData sMain(which_thread++);
        // We need not reset() the local_ptr to this instance; we'll simply
        // find it again every time we discover that current is null.
        current = &sMain;
    }
    return *current;
}

//static
LLCoros::coro::id LLCoros::get_self()
{
    return boost::this_fiber::get_id();
}

//static
void LLCoros::set_consuming(bool consuming)
{
    CoroData& data(get_CoroData("set_consuming()"));
    // DO NOT call this on the main() coroutine.
    llassert_always(! data.mName.empty());
    data.mConsuming = consuming;
}

//static
bool LLCoros::get_consuming()
{
    return get_CoroData("get_consuming()").mConsuming;
}

// static
void LLCoros::setStatus(const std::string& status)
{
    get_CoroData("setStatus()").mStatus = status;
}

// static
std::string LLCoros::getStatus()
{
    return get_CoroData("getStatus()").mStatus;
}

LLCoros::LLCoros():
    // MAINT-2724: default coroutine stack size too small on Windows.
    // Previously we used
    // boost::context::guarded_stack_allocator::default_stacksize();
    // empirically this is insufficient.
    mStackSize(900*1024),
    // mCurrent does NOT own the current CoroData instance -- it simply
    // points to it. So initialize it with a no-op deleter.
    mCurrent{ [](CoroData*){} }
{
}

LLCoros::~LLCoros()
{
}

void LLCoros::cleanupSingleton()
{
    // Some of the coroutines (like voice) will depend onto
    // origin singletons, so clean coros before deleting those

    printActiveCoroutines("at entry to ~LLCoros()");
    // Other LLApp status-change listeners do things like close
    // work queues and inject the Stop exception into pending
    // promises, to force coroutines waiting on those things to
    // notice and terminate. The only problem is that by the time
    // LLApp sets "quitting" status, the main loop has stopped
    // pumping the fiber scheduler with yield() calls. A waiting
    // coroutine still might not wake up until after resources on
    // which it depends have been freed. Pump it a few times
    // ourselves. Of course, stop pumping as soon as the last of
    // the coroutines has terminated.
    for (size_t count = 0; count < 10 && CoroData::instanceCount() > 0; ++count)
    {
        // don't use llcoro::suspend() because that module depends
        // on this one
        // This will yield current(main) thread and will let active
        // corutines run once
        boost::this_fiber::yield();
    }
    printActiveCoroutines("after pumping");
}

std::string LLCoros::generateDistinctName(const std::string& prefix) const
{
    static int unique = 0;

    // Allowing empty name would make getName()'s not-found return ambiguous.
    if (prefix.empty())
    {
        LL_ERRS("LLCoros") << "LLCoros::launch(): pass non-empty name string" << LL_ENDL;
    }

    // If the specified name isn't already in the map, just use that.
    std::string name(prefix);

    // Until we find an unused name, append a numeric suffix for uniqueness.
    while (CoroData::getInstance(name))
    {
        name = STRINGIZE(prefix << unique++);
    }
    return name;
}

/*==========================================================================*|
bool LLCoros::kill(const std::string& name)
{
    CoroMap::iterator found = mCoros.find(name);
    if (found == mCoros.end())
    {
        return false;
    }
    // Because this is a boost::ptr_map, erasing the map entry also destroys
    // the referenced heap object, in this case the boost::coroutine object,
    // which will terminate the coroutine.
    mCoros.erase(found);
    return true;
}
|*==========================================================================*/

//static
std::string LLCoros::getName()
{
    return get_CoroData("getName()").mName;
}

//static
std::string LLCoros::logname()
{
    LLCoros::CoroData& data(get_CoroData("logname()"));
    return data.mName.empty()? data.getKey() : data.mName;
}

void LLCoros::saveException(const std::string& name, std::exception_ptr exc)
{
    mExceptionQueue.emplace(name, exc);
}

void LLCoros::rethrow()
{
    if (! mExceptionQueue.empty())
    {
        ExceptionData front = mExceptionQueue.front();
        mExceptionQueue.pop();
        LL_WARNS("LLCoros") << "Rethrowing exception from coroutine " << front.name << LL_ENDL;
        std::rethrow_exception(front.exception);
    }
}

void LLCoros::setStackSize(S32 stacksize)
{
    LL_DEBUGS("LLCoros") << "Setting coroutine stack size to " << stacksize << LL_ENDL;
    mStackSize = stacksize;
}

void LLCoros::printActiveCoroutines(const std::string& when)
{
    LL_INFOS("LLCoros") << "Number of active coroutines " << when
                        << ": " << CoroData::instanceCount() << LL_ENDL;
    if (CoroData::instanceCount() > 0)
    {
        LL_INFOS("LLCoros") << "-------------- List of active coroutines ------------";
        F64 time = LLTimer::getTotalSeconds();
        for (auto& cd : CoroData::instance_snapshot())
        {
            F64 life_time = time - cd.mCreationTime;
            LL_CONT << LL_NEWLINE
                    << cd.getKey() << ' ' << cd.mStatus << " life: " << life_time;
        }
        LL_CONT << LL_ENDL;
        LL_INFOS("LLCoros") << "-----------------------------------------------------" << LL_ENDL;
    }
}

std::string LLCoros::launch(const std::string& prefix, const callable_t& callable)
{
    std::string name(generateDistinctName(prefix));
    // 'dispatch' means: enter the new fiber immediately, returning here only
    // when the fiber yields for whatever reason.
    // std::allocator_arg is a flag to indicate that the following argument is
    // a StackAllocator.
    // protected_fixedsize_stack sets a guard page past the end of the new
    // stack so that stack underflow will result in an access violation
    // instead of weird, subtle, possibly undiagnosed memory stomps.

    try
    {
        boost::fibers::fiber newCoro(boost::fibers::launch::dispatch,
            std::allocator_arg,
            boost::fibers::protected_fixedsize_stack(mStackSize),
            [this, &name, &callable]() { toplevel(name, callable); });

        // You have two choices with a fiber instance: you can join() it or you
        // can detach() it. If you try to destroy the instance before doing
        // either, the program silently terminates. We don't need this handle.
        newCoro.detach();
    }
    catch (std::bad_alloc&)
    {
        // Out of memory on stack allocation?
        LLError::LLUserWarningMsg::showOutOfMemory();
        printActiveCoroutines();
        LL_ERRS("LLCoros") << "Bad memory allocation in LLCoros::launch(" << prefix << ")!" << LL_ENDL;
    }

    return name;
}

namespace
{

#if LL_WINDOWS

static const U32 STATUS_MSC_EXCEPTION = 0xE06D7363; // compiler specific

U32 exception_filter(U32 code, struct _EXCEPTION_POINTERS *exception_infop)
{
    if (code == STATUS_MSC_EXCEPTION)
    {
        // C++ exception, go on
        return EXCEPTION_CONTINUE_SEARCH;
    }
    else
    {
        // handle it
        return EXCEPTION_EXECUTE_HANDLER;
    }
}

void sehandle(const LLCoros::callable_t& callable)
{
    __try
    {
        callable();
    }
    __except (exception_filter(GetExceptionCode(), GetExceptionInformation()))
    {
        // convert to C++ styled exception
        // Note: it might be better to use _se_set_translator
        // if you want exception to inherit full callstack
        char integer_string[512];
        sprintf(integer_string, "SEH, code: %lu\n", GetExceptionCode());
        throw std::exception(integer_string);
    }
}

#else  // ! LL_WINDOWS

inline void sehandle(const LLCoros::callable_t& callable)
{
    callable();
}

#endif // ! LL_WINDOWS

} // anonymous namespace

// Top-level wrapper around caller's coroutine callable.
// Normally we like to pass strings and such by const reference -- but in this
// case, we WANT to copy both the name and the callable to our local stack!
void LLCoros::toplevel(std::string name, callable_t callable)
{
    // keep the CoroData on this top-level function's stack frame
    CoroData corodata(name);
    // set it as current
    mCurrent.reset(&corodata);

    // run the code the caller actually wants in the coroutine
    try
    {
        sehandle(callable);
    }
    catch (const Stop& exc)
    {
        LL_INFOS("LLCoros") << "coroutine " << name << " terminating because "
                            << exc.what() << LL_ENDL;
    }
    catch (const LLContinueError&)
    {
        // Any uncaught exception derived from LLContinueError will be caught
        // here and logged. This coroutine will terminate but the rest of the
        // viewer will carry on.
        LOG_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << name));
    }
    catch (...)
    {
        // Stash any OTHER kind of uncaught exception in the rethrow() queue
        // to be rethrown by the main fiber.
        LL_WARNS("LLCoros") << "Capturing uncaught exception in coroutine "
                            << name << LL_ENDL;
        LLCoros::instance().saveException(name, std::current_exception());
    }
}

//static
void LLCoros::checkStop()
{
    if (wasDeleted())
    {
        LLTHROW(Shutdown("LLCoros was deleted"));
    }
    // do this AFTER the check above, because getName() depends on
    // get_CoroData(), which depends on the local_ptr in our instance().
    if (getName().empty())
    {
        // Our Stop exception and its subclasses are intended to stop loitering
        // coroutines. Don't throw it from the main coroutine.
        return;
    }
    if (LLApp::isStopped())
    {
        LLTHROW(Stopped("viewer is stopped"));
    }
    if (! LLApp::isRunning())
    {
        LLTHROW(Stopping("viewer is stopping"));
    }
}

LLCoros::CoroData::CoroData(const std::string& name):
    LLInstanceTracker<CoroData, std::string>(name),
    mName(name),
    // don't consume events unless specifically directed
    mConsuming(false),
    mCreationTime(LLTimer::getTotalSeconds())
{
}

LLCoros::CoroData::CoroData(int n):
    // This constructor is used for the thread_local instance belonging to the
    // default coroutine on each thread. We must give each one a different
    // LLInstanceTracker key because LLInstanceTracker's map spans all
    // threads, but we want the default coroutine on each thread to have the
    // empty string as its visible name because some consumers test for that.
    LLInstanceTracker<CoroData, std::string>("main" + stringize(n)),
    mName(),
    mConsuming(false),
    mCreationTime(LLTimer::getTotalSeconds())
{
}