source: libcfa/src/concurrency/coroutine.cfa @ c960331

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since c960331 was c960331, checked in by Andrew Beach <ajbeach@…>, 13 months ago

Attempt to clean-up the exception headers. I think this is easier to follow.

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File size: 8.3 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 : Fri Oct 23 23:05:24 2020
13// Update Count     : 22
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
31#define __CFA_INVOKE_PRIVATE__
32#include "invoke.h"
33
34extern "C" {
35        void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage, struct $coroutine *) __attribute__ ((__noreturn__));
36        static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) __attribute__ ((__noreturn__));
37        static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) {
38                abort();
39        }
40
41        extern void CtxRet( struct __stack_context_t * to ) asm ("CtxRet") __attribute__ ((__noreturn__));
42}
43
44//-----------------------------------------------------------------------------
45FORALL_DATA_INSTANCE(CoroutineCancelled, (dtype coroutine_t), (coroutine_t))
46
47forall(dtype T)
48void mark_exception(CoroutineCancelled(T) *) {}
49
50forall(dtype T)
51void copy(CoroutineCancelled(T) * dst, CoroutineCancelled(T) * src) {
52        dst->virtual_table = src->virtual_table;
53        dst->the_coroutine = src->the_coroutine;
54        dst->the_exception = src->the_exception;
55}
56
57forall(dtype T)
58const char * msg(CoroutineCancelled(T) *) {
59        return "CoroutineCancelled(...)";
60}
61
62// This code should not be inlined. It is the error path on resume.
63forall(dtype T | is_coroutine(T))
64void __cfaehm_cancelled_coroutine( T & cor, $coroutine * desc ) {
65        verify( desc->cancellation );
66        desc->state = Cancelled;
67        exception_t * except = __cfaehm_cancellation_exception( desc->cancellation );
68
69        // TODO: Remove explitate vtable set once trac#186 is fixed.
70        CoroutineCancelled(T) except;
71        except.virtual_table = &get_exception_vtable(&except);
72        except.the_coroutine = &cor;
73        except.the_exception = except;
74        throwResume 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
87
88void __stack_prepare( __stack_info_t * this, size_t create_size );
89
90//-----------------------------------------------------------------------------
91// Coroutine ctors and dtors
92void ?{}( __stack_info_t & this, void * storage, size_t storageSize ) {
93        this.storage   = (__stack_t *)storage;
94
95        // Did we get a piece of storage ?
96        if (this.storage || storageSize != 0) {
97                // We either got a piece of storage or the user asked for a specific size
98                // Immediately create the stack
99                // (This is slightly unintuitive that non-default sized coroutines create are eagerly created
100                // but it avoids that all coroutines carry an unnecessary size)
101                verify( storageSize != 0 );
102                __stack_prepare( &this, storageSize );
103        }
104}
105
106void ^?{}(__stack_info_t & this) {
107        bool userStack = ((intptr_t)this.storage & 0x1) != 0;
108        if ( ! userStack && this.storage ) {
109                __attribute__((may_alias)) intptr_t * istorage = (intptr_t *)&this.storage;
110                *istorage &= (intptr_t)-1;
111
112                void * storage = this.storage->limit;
113                __cfaabi_dbg_debug_do(
114                        storage = (char*)(storage) - __page_size;
115                        if ( mprotect( storage, __page_size, PROT_READ | PROT_WRITE ) == -1 ) {
116                                abort( "(coStack_t *)%p.^?{}() : internal error, mprotect failure, error(%d) %s.", &this, errno, strerror( errno ) );
117                        }
118                );
119                __cfaabi_dbg_print_safe("Kernel : Deleting stack %p\n", storage);
120                free( storage );
121        }
122}
123
124void ?{}( $coroutine & this, const char name[], void * storage, size_t storageSize ) with( this ) {
125        (this.context){0p, 0p};
126        (this.stack){storage, storageSize};
127        this.name = name;
128        state = Start;
129        starter = 0p;
130        last = 0p;
131        cancellation = 0p;
132}
133
134void ^?{}($coroutine& this) {
135        if(this.state != Halted && this.state != Start && this.state != Primed) {
136                $coroutine * src = TL_GET( this_thread )->curr_cor;
137                $coroutine * dst = &this;
138
139                struct _Unwind_Exception storage;
140                storage.exception_class = -1;
141                storage.exception_cleanup = _CtxCoroutine_UnwindCleanup;
142                this.cancellation = &storage;
143                this.last = src;
144
145                // not resuming self ?
146                if ( src == dst ) {
147                        abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src );
148                }
149
150                $ctx_switch( src, dst );
151        }
152}
153
154// Part of the Public API
155// Not inline since only ever called once per coroutine
156forall(dtype T | is_coroutine(T))
157void prime(T& cor) {
158        $coroutine* this = get_coroutine(cor);
159        assert(this->state == Start);
160
161        this->state = Primed;
162        resume(cor);
163}
164
165[void *, size_t] __stack_alloc( size_t storageSize ) {
166        const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
167        assert(__page_size != 0l);
168        size_t size = libCeiling( storageSize, 16 ) + stack_data_size;
169
170        // If we are running debug, we also need to allocate a guardpage to catch stack overflows.
171        void * storage;
172        __cfaabi_dbg_debug_do(
173                storage = memalign( __page_size, size + __page_size );
174        );
175        __cfaabi_dbg_no_debug_do(
176                storage = (void*)malloc(size);
177        );
178
179        __cfaabi_dbg_print_safe("Kernel : Created stack %p of size %zu\n", storage, size);
180        __cfaabi_dbg_debug_do(
181                if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) {
182                        abort( "__stack_alloc : internal error, mprotect failure, error(%d) %s.", (int)errno, strerror( (int)errno ) );
183                }
184                storage = (void *)(((intptr_t)storage) + __page_size);
185        );
186
187        verify( ((intptr_t)storage & (libAlign() - 1)) == 0ul );
188        return [storage, size];
189}
190
191void __stack_prepare( __stack_info_t * this, size_t create_size ) {
192        const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
193        bool userStack;
194        void * storage;
195        size_t size;
196        if ( !this->storage ) {
197                userStack = false;
198                [storage, size] = __stack_alloc( create_size );
199        } else {
200                userStack = true;
201                __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);
202
203                // The stack must be aligned, advance the pointer to the next align data
204                storage = (void*)libCeiling( (intptr_t)this->storage, libAlign());
205
206                // The size needs to be shrinked to fit all the extra data structure and be aligned
207                ptrdiff_t diff = (intptr_t)storage - (intptr_t)this->storage;
208                size = libFloor(create_size - stack_data_size - diff, libAlign());
209        } // if
210        assertf( size >= MinStackSize, "Stack size %zd provides less than minimum of %zd bytes for a stack.", size, MinStackSize );
211
212        this->storage = (__stack_t *)((intptr_t)storage + size);
213        this->storage->limit = storage;
214        this->storage->base  = (void*)((intptr_t)storage + size);
215        this->storage->exception_context.top_resume = 0p;
216        this->storage->exception_context.current_exception = 0p;
217        __attribute__((may_alias)) intptr_t * istorage = (intptr_t*)&this->storage;
218        *istorage |= userStack ? 0x1 : 0x0;
219}
220
221// We need to call suspend from invoke.c, so we expose this wrapper that
222// is not inline (We can't inline Cforall in C)
223extern "C" {
224        void __cfactx_cor_leave( struct $coroutine * src ) {
225                $coroutine * starter = src->cancellation != 0 ? src->last : src->starter;
226
227                src->state = Halted;
228
229                assertf( starter != 0,
230                        "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n"
231                        "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
232                        src->name, src );
233                assertf( starter->state != Halted,
234                        "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n"
235                        "Possible cause is terminated coroutine's main routine has already returned.",
236                        src->name, src, starter->name, starter );
237
238                $ctx_switch( src, starter );
239        }
240
241        struct $coroutine * __cfactx_cor_finish(void) {
242                struct $coroutine * cor = kernelTLS.this_thread->curr_cor;
243
244                if(cor->state == Primed) {
245                        __cfactx_suspend();
246                }
247
248                cor->state = Active;
249
250                return cor;
251        }
252}
253
254// Local Variables: //
255// mode: c //
256// tab-width: 4 //
257// End: //
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