source: libcfa/src/concurrency/invoke.h

//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// invoke.h --
//
// Author           : Thierry Delisle
// Created On       : Tue Jan 17 12:27:26 2016
// Last Modified By : Peter A. Buhr
// Last Modified On : Wed Aug 30 21:27:51 2023
// Update Count     : 60
//

// No not use #pragma once was this file is included twice in some places. It has its own guard system.

#include "bits/collections.hfa"
#include "bits/defs.hfa"
#include "bits/locks.hfa"
#include "bits/random.hfa"
#include "kernel/fwd.hfa"

#ifdef __cforall
#include "collections/list.hfa"
extern "C" {
#endif

#if ! defined(__CFA_INVOKE_PRIVATE__)
#ifndef _INVOKE_H_
#define _INVOKE_H_

        enum { DEFAULT_STACK_SIZE = 65000 };

        struct __cfaehm_try_resume_node;
        struct __cfaehm_base_exception_t;
        struct exception_context_t {
                struct __cfaehm_try_resume_node * top_resume;
                struct __cfaehm_base_exception_t * current_exception;
        };

        struct __stack_context_t {
                void * SP;
                void * FP;
        };

        // low adresses  :           +----------------------+ <- start of allocation
        //                           |  optional guard page |
        //                           +----------------------+ <- __stack_t.limit
        //                           |                      |
        //                           |       /\ /\ /\       |
        //                           |       || || ||       |
        //                           |                      |
        //                           |    program  stack    |
        //                           |                      |
        // __stack_info_t.storage -> +----------------------+ <- __stack_t.base
        //                           |      __stack_t       |
        // high adresses :           +----------------------+ <- end of allocation

        struct __stack_t {
                // stack grows towards stack limit
                void * limit;

                // base of stack
                void * base;

                // Information for exception handling.
                struct exception_context_t exception_context;
        };

        struct __stack_info_t {
                // pointer to stack
                struct __stack_t * storage;
        };

    struct nonlocal_ehm {
        // list of pending nonlocal exceptions
        __queue_t(struct nonlocal_exception) ehm_buffer;

        // lock to protect the buffer
        struct __spinlock_t buffer_lock;

        // enable/disabled flag
        bool ehm_enabled;
    };

        enum __Coroutine_State { Halted, Start, Primed, Blocked, Ready, Active, Cancelled, Halting };

        struct coroutine$ {
                // context that is switch during a __cfactx_switch
                struct __stack_context_t context;

                // stack information of the coroutine
                struct __stack_info_t stack;

                // textual name for coroutine/task
                const char * name;

                // current execution status for coroutine
                enum __Coroutine_State state;

                // first coroutine to resume this one
                struct coroutine$ * starter;

                // last coroutine to resume this one
                struct coroutine$ * last;

                // If non-null stack must be unwound with this exception
                struct _Unwind_Exception * cancellation;

        // Non-local exception handling information
        struct nonlocal_ehm ehm_state;
        };
        // Wrapper for gdb
        struct cfathread_coroutine_t { struct coroutine$ debug; };

        static inline struct __stack_t * __get_stack( struct coroutine$ * cor ) {
                return (struct __stack_t*)(((uintptr_t)cor->stack.storage) & ((uintptr_t)-2));
        }

        // struct which calls the monitor is accepting
        struct __waitfor_mask_t {
                // the index of the accepted function, -1 if none
                short * accepted;

                // list of acceptable functions, null if any
                __cfa_anonymous_object( __small_array_t(struct __acceptable_t) );
        };

        struct monitor$ {
                // spinlock to protect internal data
                struct __spinlock_t lock;

                // current owner of the monitor
                struct thread$ * owner;

                // queue of threads that are blocked waiting for the monitor
                __queue_t(struct thread$) entry_queue;

                // stack of conditions to run next once we exit the monitor
                __stack_t(struct __condition_criterion_t) signal_stack;

                // monitor routines can be called recursively, we need to keep track of that
                unsigned int recursion;

                // mask used to know if some thread is waiting for something while holding the monitor
                struct __waitfor_mask_t mask;

                // node used to signal the dtor in a waitfor dtor
                struct __condition_node_t * dtor_node;
        };
        // Wrapper for gdb
        struct cfathread_monitor_t { struct monitor$ debug; };

        struct __monitor_group_t {
                // currently held monitors
                __cfa_anonymous_object( __small_array_t(monitor$*) );

                // last function that acquired monitors
                fptr_t func;
        };

        // Link lists fields
        // instrusive link field for threads in the ready-queue
        struct __thread_desc_link {
                struct thread$ * next;
                volatile unsigned long long ts;
        };

        // Link lists fields
        // instrusive link field for threads in the user_link/cltr_link
        struct __thread_user_link {
                #ifdef __cforall
                        inline dlink(thread$);
                #else
                        struct thread$ * next; struct thread$ * back;
                #endif
        };
        _Static_assert(sizeof(struct __thread_user_link) == 2 * sizeof(struct thread$ *), "__thread_user_link should be consistent in C and Cforall");

        struct thread$ {
                // Core threading fields
                // context that is switch during a __cfactx_switch
                struct __stack_context_t context;

                // Link lists fields
                // instrusive link field for threads
                struct __thread_desc_link rdy_link;

                // current execution status for coroutine
                // Possible values are:
                //    - TICKET_BLOCKED (-1) thread is blocked
                //    - TICKET_RUNNING ( 0) thread is running
                //    - TICKET_UNBLOCK ( 1) thread should ignore next block
                volatile int ticket;
                enum __Coroutine_State state:8;
                enum __Preemption_Reason preempted:8;

                bool corctx_flag;

                //SKULLDUGGERY errno is not save in the thread data structure because returnToKernel appears to be the only function to require saving and restoring it

                // pointer to the cluster on which the thread is running
                struct cluster * curr_cluster;

                // preferred ready-queue or CPU
                unsigned preferred;

                // coroutine body used to store context
                struct coroutine$  self_cor;

                // current active context
                struct coroutine$ * curr_cor;

                // monitor body used for mutual exclusion
                struct monitor$    self_mon;

                // pointer to monitor with sufficient lifetime for current monitors
                struct monitor$ *  self_mon_p;

                // monitors currently held by this thread
                struct __monitor_group_t monitors;

                // intrusive link fields, used for locks, monitors and any user defined data structure
                // default link fields for dlist
                struct __thread_user_link user_link;

                // secondary intrusive link fields, used for global cluster list
                // default link fields for dlist
                struct __thread_user_link cltr_link;

                struct processor * last_proc;

        // ptr used during handover between blocking lists to allow for stack allocation of intrusive nodes
        // main use case is wait-morphing to allow a different node to be used to block on condvar vs lock
        void * link_node;

                PRNG_STATE_T random_state;                                              // fast random numbers

                #if defined( __CFA_WITH_VERIFY__ )
                        struct processor * volatile executing;
                        void * canary;
                #endif
        };

        // Wrapper for gdb
        struct cfathread_thread_t { struct thread$ debug; };

        #ifdef __CFA_DEBUG__
                void __cfaabi_dbg_record_thrd(thread$ & this, bool park, const char prev_name[]);
        #else
                #define __cfaabi_dbg_record_thrd(x, y, z)
        #endif

        #ifdef __cforall
        extern "Cforall" {
        static inline bool exception_in_flight() {
            return __get_stack( &active_thread()->self_cor )->exception_context.current_exception != 0p;
        }

                static inline thread$ * volatile & ?`next ( thread$ * this ) {
                        return this->user_link.next;
                }

                static inline thread$ *& get_next( thread$ & this ) __attribute__((const)) {
                        return this.user_link.next;
                }

                static inline tytagref( dlink(thread$), dlink(thread$) ) ?`inner( thread$ & this ) {
                        dlink(thread$) & b = this.user_link;
                        tytagref( dlink(thread$), dlink(thread$) ) result = { b };
                        return result;
                }

                static inline tytagref(struct __thread_user_link, dlink(thread$)) ?`inner( struct thread$ & this ) {
                        struct __thread_user_link & ib = this.cltr_link;
                        dlink(thread$) & b = ib`inner;
                        tytagref(struct __thread_user_link, dlink(thread$)) result = { b };
                        return result;
                }

                P9_EMBEDDED(struct __thread_user_link, dlink(thread$))

                static inline void ?{}(__monitor_group_t & this) {
                        (this.data){0p};
                        (this.size){0};
                        (this.func){NULL};
                }

                static inline void ?{}(__monitor_group_t & this, struct monitor$ ** data, __lock_size_t size, fptr_t func) {
                        (this.data){data};
                        (this.size){size};
                        (this.func){func};
                }

                static inline bool ?==?( const __monitor_group_t & lhs, const __monitor_group_t & rhs ) __attribute__((const)) {
                        if( (lhs.data != 0) != (rhs.data != 0) ) return false;
                        if( lhs.size != rhs.size ) return false;
                        if( lhs.func != rhs.func ) return false;

                        // Check that all the monitors match
                        for( int i = 0; i < lhs.size; i++ ) {
                                // If not a match, check next function
                                if( lhs[i] != rhs[i] ) return false;
                        }

                        return true;
                }

                static inline void ?=?(__monitor_group_t & lhs, const __monitor_group_t & rhs) {
                        lhs.data = rhs.data;
                        lhs.size = rhs.size;
                        lhs.func = rhs.func;
                }
        }
        #endif

#endif //_INVOKE_H_
#else //! defined(__CFA_INVOKE_PRIVATE__)
#ifndef _INVOKE_PRIVATE_H_
#define _INVOKE_PRIVATE_H_

        struct machine_context_t {
                void *SP;
                void *FP;
                void *PC;
        };

        // assembler routines that performs the context switch
        extern void __cfactx_invoke_stub( void );
        extern void __cfactx_switch( struct __stack_context_t * from, struct __stack_context_t * to ) asm ("__cfactx_switch");
        // void CtxStore ( void * this ) asm ("CtxStore");
        // void CtxRet   ( void * dst  ) asm ("CtxRet");

#endif //_INVOKE_PRIVATE_H_
#endif //! defined(__CFA_INVOKE_PRIVATE__)
#ifdef __cforall
}
#endif

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