source: libcfa/src/concurrency/coroutine.hfa

Last change on this file was e84ab3d, checked in by Thierry Delisle <tdelisle@…>, 5 months ago

Step 1 of changing $thread to thread$

  • Property mode set to 100644
File size: 7.2 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// coroutine --
8//
9// Author           : Thierry Delisle
10// Created On       : Mon Nov 28 12:27:26 2016
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Tue Feb  4 12:29:26 2020
13// Update Count     : 11
14//
15
16#pragma once
17
18#include <assert.h>
19#include "invoke.h"
20#include "../exception.hfa"
21
22//-----------------------------------------------------------------------------
23// Exception thrown from resume when a coroutine stack is cancelled.
24EHM_FORALL_EXCEPTION(CoroutineCancelled, (coroutine_t &), (coroutine_t)) (
25        coroutine_t * the_coroutine;
26        exception_t * the_exception;
27);
28
29forall(T &)
30void copy(CoroutineCancelled(T) * dst, CoroutineCancelled(T) * src);
31
32forall(T &)
33const char * msg(CoroutineCancelled(T) *);
34
35//-----------------------------------------------------------------------------
36// Coroutine trait
37// Anything that implements this trait can be resumed.
38// Anything that is resumed is a coroutine.
39trait is_coroutine(T & | IS_RESUMPTION_EXCEPTION(CoroutineCancelled, (T))) {
40        void main(T & this);
41        coroutine$ * get_coroutine(T & this);
42};
43
44#define DECL_COROUTINE(X) static inline coroutine$* get_coroutine(X& this) { return &this.__cor; } void main(X& this)
45
46//-----------------------------------------------------------------------------
47// Ctors and dtors
48// void ?{}( coStack_t & this );
49// void ^?{}( coStack_t & this );
50
51void  ?{}( coroutine$ & this, const char name[], void * storage, size_t storageSize );
52void ^?{}( coroutine$ & this );
53
54static inline void ?{}( coroutine$ & this)                                       { this{ "Anonymous Coroutine", 0p, 0 }; }
55static inline void ?{}( coroutine$ & this, size_t stackSize)                     { this{ "Anonymous Coroutine", 0p, stackSize }; }
56static inline void ?{}( coroutine$ & this, void * storage, size_t storageSize )  { this{ "Anonymous Coroutine", storage, storageSize }; }
57static inline void ?{}( coroutine$ & this, const char name[])                    { this{ name, 0p, 0 }; }
58static inline void ?{}( coroutine$ & this, const char name[], size_t stackSize ) { this{ name, 0p, stackSize }; }
59
60//-----------------------------------------------------------------------------
61// Public coroutine API
62forall(T & | is_coroutine(T) | { EHM_DEFAULT_VTABLE(CoroutineCancelled, (T)); })
63void prime(T & cor);
64
65static inline struct coroutine$ * active_coroutine() { return active_thread()->curr_cor; }
66
67//-----------------------------------------------------------------------------
68// PRIVATE exposed because of inline
69
70// Start coroutine routines
71extern "C" {
72        void __cfactx_invoke_coroutine(void (*main)(void *), void * this);
73
74        forall(T &)
75        void __cfactx_start(void (*main)(T &), struct coroutine$ * cor, T & this, void (*invoke)(void (*main)(void *), void *));
76
77        extern void __cfactx_coroutine_unwind(struct _Unwind_Exception * storage, struct coroutine$ *) __attribute__ ((__noreturn__));
78
79        extern void __cfactx_switch( struct __stack_context_t * from, struct __stack_context_t * to ) asm ("__cfactx_switch");
80}
81
82// Private wrappers for context switch and stack creation
83// Wrapper for co
84static inline void $ctx_switch( coroutine$ * src, coroutine$ * dst ) __attribute__((nonnull (1, 2))) {
85        // set state of current coroutine to inactive
86        src->state = src->state == Halted ? Halted : Blocked;
87
88        // get the active thread once
89        thread$ * athrd = active_thread();
90
91        // Mark the coroutine
92        /* paranoid */ verify( !athrd->corctx_flag );
93        athrd->corctx_flag = true;
94
95        // set new coroutine that task is executing
96        athrd->curr_cor = dst;
97
98        // context switch to specified coroutine
99        /* paranoid */ verify( dst->context.SP );
100        __cfactx_switch( &src->context, &dst->context );
101        // when __cfactx_switch returns we are back in the src coroutine
102
103        /* paranoid */ verify( athrd->corctx_flag );
104        athrd->corctx_flag = false;
105
106        // set state of new coroutine to active
107        src->state = Active;
108
109        if( unlikely(src->cancellation != 0p) ) {
110                __cfactx_coroutine_unwind(src->cancellation, src);
111        }
112}
113
114extern void __stack_prepare( __stack_info_t * this, size_t size /* ignored if storage already allocated */);
115extern void __stack_clean  ( __stack_info_t * this );
116
117
118// Suspend implementation inlined for performance
119extern "C" {
120        static inline void __cfactx_suspend(void) {
121                // optimization : read TLS once and reuse it
122                // Safety note: this is preemption safe since if
123                // preemption occurs after this line, the pointer
124                // will also migrate which means this value will
125                // stay in syn with the TLS
126                coroutine$ * src = active_coroutine();
127
128                assertf( src->last != 0,
129                        "Attempt to suspend coroutine \"%.256s\" (%p) that has never been resumed.\n"
130                        "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
131                        src->name, src );
132                assertf( src->last->state != Halted,
133                        "Attempt by coroutine \"%.256s\" (%p) to suspend back to terminated coroutine \"%.256s\" (%p).\n"
134                        "Possible cause is terminated coroutine's main routine has already returned.",
135                        src->name, src, src->last->name, src->last );
136
137                $ctx_switch( src, src->last );
138        }
139}
140
141forall(T & | is_coroutine(T))
142void __cfaehm_cancelled_coroutine(
143        T & cor, coroutine$ * desc, EHM_DEFAULT_VTABLE(CoroutineCancelled, (T)) );
144
145// Resume implementation inlined for performance
146forall(T & | is_coroutine(T) | { EHM_DEFAULT_VTABLE(CoroutineCancelled, (T)); })
147static inline T & resume(T & cor) {
148        // optimization : read TLS once and reuse it
149        // Safety note: this is preemption safe since if
150        // preemption occurs after this line, the pointer
151        // will also migrate which means this value will
152        // stay in syn with the TLS
153        coroutine$ * src = active_coroutine();
154        coroutine$ * dst = get_coroutine(cor);
155
156        if( unlikely(dst->context.SP == 0p) ) {
157                __stack_prepare(&dst->stack, 65000);
158                __cfactx_start(main, dst, cor, __cfactx_invoke_coroutine);
159        }
160
161        // not resuming self ?
162        if ( src != dst ) {
163                assertf( dst->state != Halted ,
164                        "Attempt by coroutine %.256s (%p) to resume terminated coroutine %.256s (%p).\n"
165                        "Possible cause is terminated coroutine's main routine has already returned.",
166                        src->name, src, dst->name, dst );
167
168                // set last resumer
169                dst->last = src;
170                dst->starter = dst->starter ? dst->starter : src;
171        }
172
173        // always done for performance testing
174        $ctx_switch( src, dst );
175        if ( unlikely(dst->cancellation) ) {
176                __cfaehm_cancelled_coroutine( cor, dst, _default_vtable );
177        }
178
179        return cor;
180}
181
182static inline void resume( coroutine$ * dst ) __attribute__((nonnull (1))) {
183        // optimization : read TLS once and reuse it
184        // Safety note: this is preemption safe since if
185        // preemption occurs after this line, the pointer
186        // will also migrate which means this value will
187        // stay in syn with the TLS
188        coroutine$ * src = active_coroutine();
189
190        // not resuming self ?
191        if ( src != dst ) {
192                assertf( dst->state != Halted ,
193                        "Attempt by coroutine %.256s (%p) to resume terminated coroutine %.256s (%p).\n"
194                        "Possible cause is terminated coroutine's main routine has already returned.",
195                        src->name, src, dst->name, dst );
196
197                // set last resumer
198                dst->last = src;
199        }
200
201        // always done for performance testing
202        $ctx_switch( src, dst );
203}
204
205// Local Variables: //
206// mode: c //
207// tab-width: 4 //
208// End: //
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