source: libcfa/src/exception.h @ 654d5a47

//
// 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.
//
// exception.h -- Internal exception handling definitions.
//
// Author           : Andrew Beach
// Created On       : Mon Jun 26 15:11:00 2017
// Last Modified By : Andrew Beach
// Last Modified On : Tue Oct 27 14:45:00 2020
// Update Count     : 11
//

#pragma once

// This could be considered several headers. All are internal to the exception
// system but needed to depending on whether they are C/Cforall code and
// whether or not they are part of the builtins.

#ifdef __cforall
extern "C" {
#endif

// Included in C code or the built-ins.
#if !defined(__cforall) || defined(__cforall_builtins__)

struct __cfaehm_base_exception_t;
typedef struct __cfaehm_base_exception_t exception_t;
struct __cfaehm_base_exception_t_vtable {
        const struct __cfaehm_base_exception_t_vtable * parent;
        size_t size;
        void (*copy)(struct __cfaehm_base_exception_t *this,
                     struct __cfaehm_base_exception_t * other);
        void (*free)(struct __cfaehm_base_exception_t *this);
        const char * (*msg)(struct __cfaehm_base_exception_t *this);
};
struct __cfaehm_base_exception_t {
        struct __cfaehm_base_exception_t_vtable const * virtual_table;
};
extern struct __cfaehm_base_exception_t_vtable
        ___cfaehm_base_exception_t_vtable_instance;


void __cfaehm_cancel_stack(exception_t * except) __attribute__((noreturn));

// Used in throw statement translation.
void __cfaehm_throw_terminate(exception_t * except, void (*)(exception_t *));
void __cfaehm_rethrow_terminate() __attribute__((noreturn));
void __cfaehm_throw_resume(exception_t * except, void (*)(exception_t *));

// Function catches termination exceptions.
void __cfaehm_try_terminate(
        void (*try_block)(),
        void (*catch_block)(int index, exception_t * except),
        int (*match_block)(exception_t * except));

// Clean-up the exception in catch blocks.
void __cfaehm_cleanup_terminate(void * except);

// Data structure creates a list of resume handlers.
struct __cfaehm_try_resume_node {
        struct __cfaehm_try_resume_node * next;
        _Bool (*handler)(exception_t * except);
};

// These act as constructor and destructor for the resume node.
void __cfaehm_try_resume_setup(
        struct __cfaehm_try_resume_node * node,
        _Bool (*handler)(exception_t * except));
void __cfaehm_try_resume_cleanup(
        struct __cfaehm_try_resume_node * node);

// Check for a standard way to call fake deconstructors.
struct __cfaehm_cleanup_hook {};

#endif

// Included in C code and the library.
#if !defined(__cforall) || !defined(__cforall_builtins__)
struct __cfaehm_node {
        struct _Unwind_Exception unwind_exception;
        struct __cfaehm_node * next;
        int handler_index;
};

static inline exception_t * __cfaehm_cancellation_exception(
                struct _Unwind_Exception * unwind_exception ) {
        return (exception_t *)(1 + (struct __cfaehm_node *)unwind_exception);
}
#endif

#ifdef __cforall
}

// Built-ins not visible in C.
#if defined(__cforall_builtins__)

// Not all the built-ins can be expressed in C. These can't be
// implemented in the .c file either so they all have to be inline.

trait is_exception(dtype exceptT, dtype virtualT) {
        /* The first field must be a pointer to a virtual table.
         * That virtual table must be a decendent of the base exception virtual table.
         */
        virtualT const & get_exception_vtable(exceptT *);
        // Always returns the virtual table for this type (associated types hack).
};

trait is_termination_exception(dtype exceptT, dtype virtualT | is_exception(exceptT, virtualT)) {
        void defaultTerminationHandler(exceptT &);
};

trait is_resumption_exception(dtype exceptT, dtype virtualT | is_exception(exceptT, virtualT)) {
        void defaultResumptionHandler(exceptT &);
};

forall(dtype exceptT, dtype virtualT | is_termination_exception(exceptT, virtualT))
static inline void $throw(exceptT & except) {
        __cfaehm_throw_terminate(
                (exception_t *)&except,
                (void(*)(exception_t *))defaultTerminationHandler
        );
}

forall(dtype exceptT, dtype virtualT | is_resumption_exception(exceptT, virtualT))
static inline void $throwResume(exceptT & except) {
        __cfaehm_throw_resume(
                (exception_t *)&except,
                (void(*)(exception_t *))defaultResumptionHandler
        );
}

forall(dtype exceptT, dtype virtualT | is_exception(exceptT, virtualT))
static inline void cancel_stack(exceptT & except) __attribute__((noreturn)) {
        __cfaehm_cancel_stack( (exception_t *)&except );
}

forall(dtype exceptT, dtype virtualT | is_exception(exceptT, virtualT))
static inline void defaultTerminationHandler(exceptT & except) {
        return cancel_stack( except );
}

forall(dtype exceptT, dtype virtualT | is_exception(exceptT, virtualT))
static inline void defaultResumptionHandler(exceptT & except) {
        throw except;
}

#endif

#endif