source: libcfa/src/concurrency/coroutine.cfa @ 578c09a

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since 578c09a was b583113, checked in by Andrew Beach <ajbeach@…>, 5 months ago

Recovered the polymorphic CoroutineCancelled? exception. The interface might need a bit of polish.

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File size: 9.4 KB
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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.c --
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 Dec 15 12:06:04 2020
13// Update Count     : 23
14//
15
16#define __cforall_thread__
17
18#include "coroutine.hfa"
19
20#include <stddef.h>
21#include <malloc.h>
22#include <errno.h>
23#include <string.h>
24#include <unistd.h>
25#include <sys/mman.h>                                                                   // mprotect
26#include <unwind.h>
27
28#include "kernel_private.hfa"
29#include "exception.hfa"
30#include "math.hfa"
31
32#define CFA_COROUTINE_USE_MMAP 0
33
34#define __CFA_INVOKE_PRIVATE__
35#include "invoke.h"
36
37extern "C" {
38        void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage, struct $coroutine *) __attribute__ ((__noreturn__));
39        static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) __attribute__ ((__noreturn__));
40        static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) {
41                abort();
42        }
43
44        extern void CtxRet( struct __stack_context_t * to ) asm ("CtxRet") __attribute__ ((__noreturn__));
45}
46
47//-----------------------------------------------------------------------------
48forall(T &)
49void copy(CoroutineCancelled(T) * dst, CoroutineCancelled(T) * src) {
50        dst->virtual_table = src->virtual_table;
51        dst->the_coroutine = src->the_coroutine;
52        dst->the_exception = src->the_exception;
53}
54
55forall(T &)
56const char * msg(CoroutineCancelled(T) *) {
57        return "CoroutineCancelled(...)";
58}
59
60// This code should not be inlined. It is the error path on resume.
61forall(T & | is_coroutine(T))
62void __cfaehm_cancelled_coroutine(
63                T & cor, $coroutine * desc, _EHM_VTABLE_TYPE(CoroutineCancelled)(T) & const _default_vtable ) {
64        verify( desc->cancellation );
65        desc->state = Cancelled;
66        exception_t * except = __cfaehm_cancellation_exception( desc->cancellation );
67
68        // TODO: Remove explitate vtable set once trac#186 is fixed.
69        CoroutineCancelled(T) except;
70        except.virtual_table = &_default_vtable;
71        except.the_coroutine = &cor;
72        except.the_exception = except;
73        // Why does this need a cast?
74        throwResume (CoroutineCancelled(T) &)except;
75
76        except->virtual_table->free( except );
77        free( desc->cancellation );
78        desc->cancellation = 0p;
79}
80
81//-----------------------------------------------------------------------------
82// Global state variables
83
84// minimum feasible stack size in bytes
85static const size_t MinStackSize = 1000;
86extern size_t __page_size;                              // architecture pagesize HACK, should go in proper runtime singleton
87extern int __map_prot;
88
89void __stack_prepare( __stack_info_t * this, size_t create_size );
90void __stack_clean  ( __stack_info_t * this );
91
92//-----------------------------------------------------------------------------
93// Coroutine ctors and dtors
94void ?{}( __stack_info_t & this, void * storage, size_t storageSize ) {
95        this.storage   = (__stack_t *)storage;
96
97        // Did we get a piece of storage ?
98        if (this.storage || storageSize != 0) {
99                // We either got a piece of storage or the user asked for a specific size
100                // Immediately create the stack
101                // (This is slightly unintuitive that non-default sized coroutines create are eagerly created
102                // but it avoids that all coroutines carry an unnecessary size)
103                verify( storageSize != 0 );
104                __stack_prepare( &this, storageSize );
105        }
106}
107
108void ^?{}(__stack_info_t & this) {
109        bool userStack = ((intptr_t)this.storage & 0x1) != 0;
110        if ( ! userStack && this.storage ) {
111                __stack_clean( &this );
112        }
113}
114
115void ?{}( $coroutine & this, const char name[], void * storage, size_t storageSize ) with( this ) {
116        (this.context){0p, 0p};
117        (this.stack){storage, storageSize};
118        this.name = name;
119        state = Start;
120        starter = 0p;
121        last = 0p;
122        cancellation = 0p;
123}
124
125void ^?{}($coroutine& this) {
126        if(this.state != Halted && this.state != Start && this.state != Primed) {
127                $coroutine * src = active_coroutine();
128                $coroutine * dst = &this;
129
130                struct _Unwind_Exception storage;
131                storage.exception_class = -1;
132                storage.exception_cleanup = _CtxCoroutine_UnwindCleanup;
133                this.cancellation = &storage;
134                this.last = src;
135
136                // not resuming self ?
137                if ( src == dst ) {
138                        abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src );
139                }
140
141                $ctx_switch( src, dst );
142        }
143}
144
145// Part of the Public API
146// Not inline since only ever called once per coroutine
147forall(T & | is_coroutine(T) | { _EHM_VTABLE_TYPE(CoroutineCancelled)(T) & const _default_vtable; })
148void prime(T& cor) {
149        $coroutine* this = get_coroutine(cor);
150        assert(this->state == Start);
151
152        this->state = Primed;
153        resume(cor);
154}
155
156[void *, size_t] __stack_alloc( size_t storageSize ) {
157        const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
158        assert(__page_size != 0l);
159        size_t size = libCeiling( storageSize, 16 ) + stack_data_size;
160        size = ceiling(size, __page_size);
161
162        // If we are running debug, we also need to allocate a guardpage to catch stack overflows.
163        void * storage;
164        #if CFA_COROUTINE_USE_MMAP
165                storage = mmap(0p, size + __page_size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
166                if(storage == ((void*)-1)) {
167                        abort( "coroutine stack creation : internal error, mmap failure, error(%d) %s.", errno, strerror( errno ) );
168                }
169                if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) {
170                        abort( "coroutine stack creation : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
171                } // if
172                storage = (void *)(((intptr_t)storage) + __page_size);
173        #else
174                __cfaabi_dbg_debug_do(
175                        storage = memalign( __page_size, size + __page_size );
176                );
177                __cfaabi_dbg_no_debug_do(
178                        storage = (void*)malloc(size);
179                );
180
181                __cfaabi_dbg_debug_do(
182                        if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) {
183                                abort( "__stack_alloc : internal error, mprotect failure, error(%d) %s.", (int)errno, strerror( (int)errno ) );
184                        }
185                        storage = (void *)(((intptr_t)storage) + __page_size);
186                );
187        #endif
188        __cfaabi_dbg_print_safe("Kernel : Created stack %p of size %zu\n", storage, size);
189
190        verify( ((intptr_t)storage & (libAlign() - 1)) == 0ul );
191        return [storage, size];
192}
193
194void __stack_clean  ( __stack_info_t * this ) {
195        void * storage = this->storage->limit;
196
197        #if CFA_COROUTINE_USE_MMAP
198                size_t size = ((intptr_t)this->storage->base) - ((intptr_t)this->storage->limit) + sizeof(__stack_t);
199                storage = (void *)(((intptr_t)storage) - __page_size);
200                if(munmap(storage, size + __page_size) == -1) {
201                        abort( "coroutine stack destruction : internal error, munmap failure, error(%d) %s.", errno, strerror( errno ) );
202                }
203        #else
204                __cfaabi_dbg_debug_do(
205                        storage = (char*)(storage) - __page_size;
206                        if ( mprotect( storage, __page_size, __map_prot ) == -1 ) {
207                                abort( "(coStack_t *)%p.^?{}() : internal error, mprotect failure, error(%d) %s.", &this, errno, strerror( errno ) );
208                        }
209                );
210
211                free( storage );
212        #endif
213        __cfaabi_dbg_print_safe("Kernel : Deleting stack %p\n", storage);
214}
215
216void __stack_prepare( __stack_info_t * this, size_t create_size ) {
217        const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
218        bool userStack;
219        void * storage;
220        size_t size;
221        if ( !this->storage ) {
222                userStack = false;
223                [storage, size] = __stack_alloc( create_size );
224        } else {
225                userStack = true;
226                __cfaabi_dbg_print_safe("Kernel : stack obj %p using user stack %p(%zd bytes)\n", this, this->storage, (intptr_t)this->storage->limit - (intptr_t)this->storage->base);
227
228                // The stack must be aligned, advance the pointer to the next align data
229                storage = (void*)libCeiling( (intptr_t)this->storage, libAlign());
230
231                // The size needs to be shrinked to fit all the extra data structure and be aligned
232                ptrdiff_t diff = (intptr_t)storage - (intptr_t)this->storage;
233                size = libFloor(create_size - stack_data_size - diff, libAlign());
234        } // if
235        assertf( size >= MinStackSize, "Stack size %zd provides less than minimum of %zd bytes for a stack.", size, MinStackSize );
236
237        this->storage = (__stack_t *)((intptr_t)storage + size - sizeof(__stack_t));
238        this->storage->limit = storage;
239        this->storage->base  = (void*)((intptr_t)storage + size - sizeof(__stack_t));
240        this->storage->exception_context.top_resume = 0p;
241        this->storage->exception_context.current_exception = 0p;
242        __attribute__((may_alias)) intptr_t * istorage = (intptr_t*)&this->storage;
243        *istorage |= userStack ? 0x1 : 0x0;
244}
245
246// We need to call suspend from invoke.c, so we expose this wrapper that
247// is not inline (We can't inline Cforall in C)
248extern "C" {
249        void __cfactx_cor_leave( struct $coroutine * src ) {
250                $coroutine * starter = src->cancellation != 0 ? src->last : src->starter;
251
252                src->state = Halted;
253
254                assertf( starter != 0,
255                        "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n"
256                        "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
257                        src->name, src );
258                assertf( starter->state != Halted,
259                        "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n"
260                        "Possible cause is terminated coroutine's main routine has already returned.",
261                        src->name, src, starter->name, starter );
262
263                $ctx_switch( src, starter );
264        }
265
266        struct $coroutine * __cfactx_cor_finish(void) {
267                struct $coroutine * cor = active_coroutine();
268
269                if(cor->state == Primed) {
270                        __cfactx_suspend();
271                }
272
273                cor->state = Active;
274
275                return cor;
276        }
277}
278
279// Local Variables: //
280// mode: c //
281// tab-width: 4 //
282// End: //
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