z3-src 415.4.4

Source distribution of the Z3 SMT solver, for use as a build dependency
Documentation 
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

/*++
Copyright (c) 2011 Microsoft Corporation

Module Name:

    scoped_timer.cpp

Abstract:

    <abstract>

Author:

    Leonardo de Moura (leonardo) 2011-04-26.

Revision History:

    Nuno Lopes (nlopes) 2019-02-04  - use C++11 goodies

--*/

#include "util/scoped_timer.h"
#include "util/mutex.h"
#include "util/util.h"
#include "util/cancel_eh.h"
#include "util/rlimit.h"
#include <atomic>
#include <chrono>
#include <climits>
#include <condition_variable>
#include <mutex>
#include <thread>
#include <vector>
#ifndef _WINDOWS
#include <pthread.h>
#endif

enum scoped_timer_work_state { IDLE = 0, WORKING = 1, EXITING = 2 };

struct scoped_timer_state {
    std::thread m_thread;
    std::timed_mutex m_mutex;
    event_handler * eh;
    unsigned ms;
    std::atomic<scoped_timer_work_state> work;
    std::condition_variable_any cv;
};

static std::vector<scoped_timer_state*> available_workers;
static std::mutex workers;

static void thread_func(scoped_timer_state *s) {
    workers.lock();
    while (true) {
        s->cv.wait(workers, [=]{ return s->work != IDLE; });
        workers.unlock();

        if (s->work == EXITING)
            return;

        auto end = std::chrono::steady_clock::now() + std::chrono::milliseconds(s->ms);

        while (!s->m_mutex.try_lock_until(end)) {
            if (std::chrono::steady_clock::now() >= end) {
                s->eh->operator()(TIMEOUT_EH_CALLER);
                goto next;
            }
        }

        s->m_mutex.unlock();

    next:
        s->work = IDLE;
        workers.lock();
    }
}


scoped_timer::scoped_timer(unsigned ms, event_handler * eh) {
    if (ms == 0 || ms == UINT_MAX)
        return;

#ifdef POLLING_TIMER
    auto* r = dynamic_cast<cancel_eh<reslimit>*>(eh);
    if (r) {
        r->t().set_timeout(ms);
        r->set_auto_cancel();
        return;
    }
#endif
    workers.lock();
    if (available_workers.empty()) {
        // start new thead
        workers.unlock();
        s = new scoped_timer_state;
        init_state(ms, eh);
        s->m_thread = std::thread(thread_func, s);
    }
    else {
        // re-use existing thread
        s = available_workers.back();
        available_workers.pop_back();
        init_state(ms, eh);
        workers.unlock();
        s->cv.notify_one();
    }
}
    
scoped_timer::~scoped_timer() {
    if (!s)
        return;

    s->m_mutex.unlock();
    while (s->work == WORKING)
        std::this_thread::yield();
    workers.lock();
    available_workers.push_back(s);
    workers.unlock();
}

void scoped_timer::initialize() {
#ifndef _WINDOWS
    static bool pthread_atfork_set = false;
    if (!pthread_atfork_set) {
        pthread_atfork(finalize, nullptr, nullptr);
        pthread_atfork_set = true;
    }
#endif
}

void scoped_timer::finalize() {
    workers.lock();
    for (auto w : available_workers) {
        w->work = EXITING;
        w->cv.notify_one();
    }
    decltype(available_workers) cleanup_workers;
    std::swap(available_workers, cleanup_workers);
    workers.unlock();

    for (auto w : cleanup_workers) {
        w->m_thread.join();
        delete w;
    }
}

void scoped_timer::init_state(unsigned ms, event_handler * eh) {
    s->ms = ms;
    s->eh = eh;
    s->m_mutex.lock();
    s->work = WORKING;
}