Alien-LibJIT

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libjit/jit/jit-insn.c  view on Meta::CPAN

		return jit_insn_call_intrinsic
			(func, descr->nfname, descr->nffunc, descr->nfdesc, value1, value2);
	}
}

/*
 * Apply a unary arithmetic operator, after coercing the
 * argument to a suitable numeric type.
 */
static jit_value_t apply_unary_arith
		(jit_function_t func, const jit_opcode_descr *descr,
		 jit_value_t value1, int int_only, int float_only,
		 int overflow_check)
{
	int oper;
	jit_type_t result_type;
	const jit_intrinsic_descr_t *desc;
	if(!value1)
	{
		return 0;
	}
	result_type = common_binary
		(value1->type, value1->type, int_only, float_only);
	if(result_type == jit_type_int)
	{
		oper = descr->ioper;
		desc = descr->idesc;
	}
	else if(result_type == jit_type_uint)
	{
		oper = descr->iuoper;
		desc = descr->iudesc;
	}
	else if(result_type == jit_type_long)
	{
		oper = descr->loper;
		desc = descr->ldesc;
	}
	else if(result_type == jit_type_ulong)
	{
		oper = descr->luoper;
		desc = descr->ludesc;
	}
	else if(result_type == jit_type_float32)
	{
		oper = descr->foper;
		desc = descr->fdesc;
	}
	else if(result_type == jit_type_float64)
	{
		oper = descr->doper;
		desc = descr->ddesc;
	}
	else
	{
		oper = descr->nfoper;
		desc = descr->nfdesc;
	}
	if(desc && desc->ptr_result_type)
	{
		func->builder->may_throw = 1;
	}
	value1 = jit_insn_convert(func, value1, result_type, overflow_check);
	if(_jit_opcode_is_supported(oper))
	{
		return apply_unary(func, oper, value1, result_type);
	}
	else
	{
		return apply_intrinsic(func, descr, value1, 0, result_type);
	}
}

/*
 * Apply a binary arithmetic operator, after coercing both
 * arguments to a common type.
 */
static jit_value_t apply_arith
		(jit_function_t func, const jit_opcode_descr *descr,
		 jit_value_t value1, jit_value_t value2,
		 int int_only, int float_only, int overflow_check)
{
	int oper;
	jit_type_t result_type;
	const jit_intrinsic_descr_t *desc;
	if(!value1 || !value2)
	{
		return 0;
	}
	result_type = common_binary
		(value1->type, value2->type, int_only, float_only);
	if(result_type == jit_type_int)
	{
		oper = descr->ioper;
		desc = descr->idesc;
	}
	else if(result_type == jit_type_uint)
	{
		oper = descr->iuoper;
		desc = descr->iudesc;
	}
	else if(result_type == jit_type_long)
	{
		oper = descr->loper;
		desc = descr->ldesc;
	}
	else if(result_type == jit_type_ulong)
	{
		oper = descr->luoper;
		desc = descr->ludesc;
	}
	else if(result_type == jit_type_float32)
	{
		oper = descr->foper;
		desc = descr->fdesc;
	}
	else if(result_type == jit_type_float64)
	{
		oper = descr->doper;
		desc = descr->ddesc;
	}
	else
	{
		oper = descr->nfoper;
		desc = descr->nfdesc;
	}
	if(desc && desc->ptr_result_type)
	{
		func->builder->may_throw = 1;
	}
	value1 = jit_insn_convert(func, value1, result_type, overflow_check);
	value2 = jit_insn_convert(func, value2, result_type, overflow_check);
	if(_jit_opcode_is_supported(oper))
	{
		return apply_binary(func, oper, value1, value2, result_type);
	}
	else
	{
		return apply_intrinsic(func, descr, value1, value2, result_type);
	}
}

/*
 * Apply a binary shift operator, after coercing both
 * arguments to suitable types.
 */
static jit_value_t apply_shift
		(jit_function_t func, const jit_opcode_descr *descr,
		 jit_value_t value1, jit_value_t value2)
{
	int oper;
	jit_type_t result_type;
	jit_type_t count_type;
	if(!value1 || !value2)
	{
		return 0;
	}
	result_type = common_binary(value1->type, value1->type, 1, 0);
	if(result_type == jit_type_int)
	{
		oper = descr->ioper;
	}
	else if(result_type == jit_type_uint)
	{
		oper = descr->iuoper;
	}
	else if(result_type == jit_type_long)
	{
		oper = descr->loper;
	}
	else if(result_type == jit_type_ulong)
	{
		oper = descr->luoper;
	}
	else
	{
		/* Shouldn't happen */
		oper = descr->loper;
	}
	count_type = jit_type_promote_int(jit_type_normalize(value2->type));
	if(count_type != jit_type_int)
	{
		count_type = jit_type_uint;
	}
	value1 = jit_insn_convert(func, value1, result_type, 0);
	value2 = jit_insn_convert(func, value2, count_type, 0);
	if(_jit_opcode_is_supported(oper))
	{
		return apply_binary(func, oper, value1, value2, result_type);

libjit/jit/jit-insn.c  view on Meta::CPAN

		jit_insn_mul(func, index,
					 jit_value_create_nint_constant
					 	(func, jit_type_nint, size)));
}

/*@
 * @deftypefun int jit_insn_store_elem (jit_function_t @var{func}, jit_value_t @var{base_addr}, jit_value_t @var{index}, jit_value_t @var{value})
 * Store @var{value} at position @var{index} of the array starting at
 * @var{base_addr}.  The effective address of the storage location is
 * @code{@var{base_addr} + @var{index} * sizeof(jit_value_get_type(@var{value}))}.
 * @end deftypefun
@*/
int jit_insn_store_elem
	(jit_function_t func, jit_value_t base_addr,
	 jit_value_t index, jit_value_t value)
{
	jit_nint size;
	int opcode;
	jit_type_t elem_type;

	/* Get the size of the element that we are fetching */
	if(!value)
	{
		return 0;
	}
	elem_type = jit_value_get_type(value);
	size = (jit_nint)(jit_type_get_size(elem_type));

	/* Convert the index into a native integer */
	index = jit_insn_convert(func, index, jit_type_nint, 0);
	if(!index)
	{
		return 0;
	}

	/* If the index is constant, then turn this into a relative store */
	if(jit_value_is_constant(index))
	{
		return jit_insn_store_relative
			(func, base_addr,
			 jit_value_get_nint_constant(index) * size, value);
	}

	/* See if we can use a special-case instruction */
	opcode = _jit_store_opcode(JIT_OP_STORE_ELEMENT_BYTE, 0, elem_type);
	if(opcode != 0 && opcode != (JIT_OP_STORE_ELEMENT_BYTE + 7))
	{
		return apply_ternary(func, opcode, base_addr, index, value);
	}

	/* Calculate the effective address and then use a relative store */
	base_addr = jit_insn_add(func, base_addr,
		jit_insn_mul(func, index,
					 jit_value_create_nint_constant
					 	(func, jit_type_nint, size)));
	return jit_insn_store_relative(func, base_addr, 0, value);
}

/*@
 * @deftypefun int jit_insn_check_null (jit_function_t @var{func}, jit_value_t @var{value})
 * Check @var{value} to see if it is NULL.  If it is, then throw the
 * built-in @code{JIT_RESULT_NULL_REFERENCE} exception.
 * @end deftypefun
@*/
int jit_insn_check_null(jit_function_t func, jit_value_t value)
{
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	/* Do the check only if the value is no not Null constant */
	if(value->is_nint_constant && (value->address != 0))
	{
		return 1;
	}
	func->builder->may_throw = 1;
	return create_unary_note(func, JIT_OP_CHECK_NULL, value);
}

int _jit_insn_check_is_redundant(const jit_insn_iter_t *iter)
{
	jit_insn_iter_t new_iter = *iter;
	jit_insn_t insn;
	jit_value_t value;

	/* Back up to find the "check_null" instruction of interest */
	insn = jit_insn_iter_previous(&new_iter);
	value = insn->value1;

	/* The value must be temporary or local, and not volatile or addressable.
	   Otherwise the value could be vulnerable to aliasing side-effects that
	   could make it NULL again even after we have checked it */
	if(!(value->is_temporary) || !(value->is_local))
	{
		return 0;
	}
	if(value->is_volatile || value->is_addressable)
	{
		return 0;
	}

	/* Search back for a previous "check_null" instruction */
	while((insn = jit_insn_iter_previous(&new_iter)) != 0)
	{
		if(insn->opcode == JIT_OP_CHECK_NULL && insn->value1 == value)
		{
			/* This is the previous "check_null" that we were looking for */
			return 1;
		}
		if(insn->opcode >= JIT_OP_STORE_RELATIVE_BYTE &&
		   insn->opcode <= JIT_OP_STORE_RELATIVE_STRUCT)
		{
			/* This stores to the memory referenced by the destination,
			   not to the destination itself, so it cannot affect "value" */
			continue;
		}
		if(insn->dest == value)
		{
			/* The value was used as a destination, so we must check */
			return 0;
		}
	}

	/* There was no previous "check_null" instruction for this value */
	return 0;
}

/*@
 * @deftypefun jit_value_t jit_insn_add (jit_function_t @var{func}, jit_value_t @var{value1}, jit_value_t @var{value2})
 * Add two values together and return the result in a new temporary value.
 * @end deftypefun
@*/
jit_value_t jit_insn_add
		(jit_function_t func, jit_value_t value1, jit_value_t value2)
{
	static jit_opcode_descr const add_descr = {

libjit/jit/jit-insn.c  view on Meta::CPAN

	}
	value_labels->free_address = 1;

	value_num_labels = jit_value_create_nint_constant(func, jit_type_uint, num_labels);
	if(!value_num_labels)
	{
		_jit_value_free(value_labels);
		return 0;
	}

	/* Add a new branch instruction */
	insn = _jit_block_add_insn(func->builder->current_block);
	if(!insn)
	{
		return 0;
	}
	jit_value_ref(func, value);

	insn->opcode = JIT_OP_JUMP_TABLE;
	insn->flags = JIT_INSN_DEST_IS_VALUE;
	insn->dest = value;
	insn->value1 = value_labels;
	insn->value2 = value_num_labels;

	/* Add a new block for the fall-through case */
	return jit_insn_new_block(func);
}

/*@
 * @deftypefun jit_value_t jit_insn_address_of (jit_function_t @var{func}, jit_value_t @var{value1})
 * Get the address of a value into a new temporary.
 * @end deftypefun
@*/
jit_value_t jit_insn_address_of(jit_function_t func, jit_value_t value1)
{
	jit_type_t type;
	jit_value_t result;
	if(!value1)
	{
		return 0;
	}
	if(jit_value_is_constant(value1))
	{
		return 0;
	}
	type = jit_type_create_pointer(jit_value_get_type(value1), 1);
	if(!type)
	{
		return 0;
	}
	jit_value_set_addressable(value1);
	result = apply_unary(func, JIT_OP_ADDRESS_OF, value1, type);
	jit_type_free(type);
	return result;
}

/*@
 * @deftypefun jit_value_t jit_insn_address_of_label (jit_function_t @var{func}, jit_label_t *@var{label})
 * Get the address of @var{label} into a new temporary.  This is typically
 * used for exception handling, to track where in a function an exception
 * was actually thrown.
 * @end deftypefun
@*/
jit_value_t jit_insn_address_of_label(jit_function_t func, jit_label_t *label)
{
	jit_value_t dest;
	jit_insn_t insn;
	if(!_jit_function_ensure_builder(func) || !label)
	{
		return 0;
	}
	if(*label == jit_label_undefined)
	{
		*label = (func->builder->next_label)++;
	}
	if(!_jit_block_record_label_flags(func, *label, JIT_LABEL_ADDRESS_OF))
	{
		return 0;
	}

	insn = _jit_block_add_insn(func->builder->current_block);
	if(!insn)
	{
		return 0;
	}
	dest = jit_value_create(func, jit_type_void_ptr);
	if(!dest)
	{
		return 0;
	}
	insn->opcode = (short)JIT_OP_ADDRESS_OF_LABEL;
	insn->flags = JIT_INSN_VALUE1_IS_LABEL;
	insn->dest = dest;
	insn->value1 = (jit_value_t)(*label);
	return dest;
}

/*
 * Information about the opcodes for a particular conversion.
 */
typedef struct jit_convert_info
{
	int			cvt1;
	jit_type_t	type1;
	int			cvt2;
	jit_type_t	type2;
	int			cvt3;
	jit_type_t	type3;

} jit_convert_info_t;
#define	CVT(opcode,name) opcode, (jit_type_t)&_jit_type_##name##_def
#define	CVT_NONE		 0, 0

/*
 * Intrinsic equivalents for the conversion opcodes.
 */
typedef struct jit_convert_intrinsic
{
	const char *name;
	void	   *func;
	jit_intrinsic_descr_t descr;

libjit/jit/jit-insn.c  view on Meta::CPAN

	CVT_INTRINSIC_CHECK(jit_long_to_uint_ovf, long, uint),
#endif
	CVT_INTRINSIC(jit_long_to_uint, long, uint),
	CVT_INTRINSIC(jit_int_to_long, int, long),
	CVT_INTRINSIC(jit_uint_to_long, uint, long),
	CVT_INTRINSIC_CHECK(jit_long_to_uint_ovf, long, uint),
	CVT_INTRINSIC_CHECK(jit_long_to_int_ovf, long, int),
	CVT_INTRINSIC_CHECK(jit_ulong_to_long_ovf, ulong, long),
	CVT_INTRINSIC_CHECK(jit_long_to_ulong_ovf, long, ulong),
	CVT_INTRINSIC(jit_float32_to_int, float32, int),
	CVT_INTRINSIC(jit_float32_to_uint, float32, uint),
	CVT_INTRINSIC(jit_float32_to_long, float32, long),
	CVT_INTRINSIC(jit_float32_to_ulong, float32, ulong),
	CVT_INTRINSIC_CHECK(jit_float32_to_int_ovf, float32, int),
	CVT_INTRINSIC_CHECK(jit_float32_to_uint_ovf, float32, uint),
	CVT_INTRINSIC_CHECK(jit_float32_to_long_ovf, float32, long),
	CVT_INTRINSIC_CHECK(jit_float32_to_ulong_ovf, float32, ulong),
	CVT_INTRINSIC(jit_int_to_float32, int, float32),
	CVT_INTRINSIC(jit_uint_to_float32, uint, float32),
	CVT_INTRINSIC(jit_long_to_float32, long, float32),
	CVT_INTRINSIC(jit_ulong_to_float32, ulong, float32),
	CVT_INTRINSIC(jit_float32_to_float64, float32, float64),
	CVT_INTRINSIC(jit_float64_to_int, float64, int),
	CVT_INTRINSIC(jit_float64_to_uint, float64, uint),
	CVT_INTRINSIC(jit_float64_to_long, float64, long),
	CVT_INTRINSIC(jit_float64_to_ulong, float64, ulong),
	CVT_INTRINSIC_CHECK(jit_float64_to_int_ovf, float64, int),
	CVT_INTRINSIC_CHECK(jit_float64_to_uint_ovf, float64, uint),
	CVT_INTRINSIC_CHECK(jit_float64_to_long_ovf, float64, long),
	CVT_INTRINSIC_CHECK(jit_float64_to_ulong_ovf, float64, ulong),
	CVT_INTRINSIC(jit_int_to_float64, int, float64),
	CVT_INTRINSIC(jit_uint_to_float64, uint, float64),
	CVT_INTRINSIC(jit_long_to_float64, long, float64),
	CVT_INTRINSIC(jit_ulong_to_float64, ulong, float64),
	CVT_INTRINSIC(jit_float64_to_float32, float64, float32),
	CVT_INTRINSIC(jit_nfloat_to_int, nfloat, int),
	CVT_INTRINSIC(jit_nfloat_to_uint, nfloat, uint),
	CVT_INTRINSIC(jit_nfloat_to_long, nfloat, long),
	CVT_INTRINSIC(jit_nfloat_to_ulong, nfloat, ulong),
	CVT_INTRINSIC_CHECK(jit_nfloat_to_int_ovf, nfloat, int),
	CVT_INTRINSIC_CHECK(jit_nfloat_to_uint_ovf, nfloat, uint),
	CVT_INTRINSIC_CHECK(jit_nfloat_to_long_ovf, nfloat, long),
	CVT_INTRINSIC_CHECK(jit_nfloat_to_ulong_ovf, nfloat, ulong),
	CVT_INTRINSIC(jit_int_to_nfloat, int, nfloat),
	CVT_INTRINSIC(jit_uint_to_nfloat, uint, nfloat),
	CVT_INTRINSIC(jit_long_to_nfloat, long, nfloat),
	CVT_INTRINSIC(jit_ulong_to_nfloat, ulong, nfloat),
	CVT_INTRINSIC(jit_nfloat_to_float32, nfloat, float32),
	CVT_INTRINSIC(jit_nfloat_to_float64, nfloat, float64),
	CVT_INTRINSIC(jit_float32_to_nfloat, float32, nfloat),
	CVT_INTRINSIC(jit_float64_to_nfloat, float64, nfloat)
};

/*
 * Apply a unary conversion operator.
 */
static jit_value_t apply_unary_conversion
		(jit_function_t func, int oper, jit_value_t value1,
		 jit_type_t result_type)
{
	/* Set the "may_throw" flag if the conversion may throw an exception */
	if(convert_intrinsics[oper - 1].descr.ptr_result_type)
	{
		func->builder->may_throw = 1;
	}

	/* Bail out early if the conversion opcode is supported by the back end */
	if(_jit_opcode_is_supported(oper))
	{
		return apply_unary(func, oper, value1, result_type);
	}

	/* Call the appropriate intrinsic method */
	return jit_insn_call_intrinsic
		(func, convert_intrinsics[oper - 1].name,
		 convert_intrinsics[oper - 1].func,
		 &(convert_intrinsics[oper - 1].descr), value1, 0);
}

/*@
 * @deftypefun jit_value_t jit_insn_convert (jit_function_t @var{func}, jit_value_t @var{value}, jit_type_t @var{type}, int @var{overflow_check})
 * Convert the contents of a value into a new type, with optional
 * overflow checking.
 * @end deftypefun
@*/
jit_value_t jit_insn_convert(jit_function_t func, jit_value_t value,
			     jit_type_t type, int overflow_check)
{
	jit_type_t vtype;
	const jit_convert_info_t *opcode_map;

	/* Bail out if we previously ran out of memory on this function */
	if(!value)
	{
		return 0;
	}

	/* Normalize the source and destination types */
	type = jit_type_normalize(type);
	vtype = jit_type_normalize(value->type);

	/* If the types are identical, then return the source value as-is */
	if(type == vtype)
	{
		return value;
	}

	/* If the source is a constant, then perform a constant conversion.
	   If an overflow might result, we perform the computation at runtime */
	if(jit_value_is_constant(value))
	{
		jit_constant_t const_value;
		const_value = jit_value_get_constant(value);
		if(jit_constant_convert(&const_value, &const_value,
					type, overflow_check))
		{
			return jit_value_create_constant(func, &const_value);
		}
	}

	/* Promote the source type, to reduce the number of cases in
	   the switch statement below */
	vtype = jit_type_promote_int(vtype);

libjit/jit/jit-insn.c  view on Meta::CPAN

			value = apply_unary_conversion
				(func, opcode_map->cvt1, value, opcode_map->type1);
		}
		if(opcode_map->cvt2)
		{
			value = apply_unary_conversion
				(func, opcode_map->cvt2, value, opcode_map->type2);
		}
		if(opcode_map->cvt3)
		{
			value = apply_unary_conversion
				(func, opcode_map->cvt3, value, opcode_map->type3);
		}
	}
	return value;
}

/*
 * Convert the parameters for a function call into their final types.
 */
static int convert_call_parameters
	(jit_function_t func, jit_type_t signature,
	 jit_value_t *args, unsigned int num_args,
	 jit_value_t *new_args)
{
	unsigned int param;
	for(param = 0; param < num_args; ++param)
	{
		new_args[param] = jit_insn_convert
			(func, args[param],
			 jit_type_get_param(signature, param), 0);
	}
	return 1;
}

/*
 * Set up the exception frame information before a function call out.
 */
static int setup_eh_frame_for_call(jit_function_t func, int flags)
{
#if !defined(JIT_BACKEND_INTERP)
	jit_type_t type;
	jit_value_t args[2];
	jit_insn_t insn;

	/* If "tail" is set, then we need to pop the "setjmp" context */
	if((flags & JIT_CALL_TAIL) != 0 && func->has_try)
	{
		type = jit_type_create_signature
			(jit_abi_cdecl, jit_type_void, 0, 0, 1);
		if(!type)
		{
			return 0;
		}
		jit_insn_call_native
			(func, "_jit_unwind_pop_setjmp",
			 (void *)_jit_unwind_pop_setjmp, type, 0, 0, JIT_CALL_NOTHROW);
		jit_type_free(type);
	}

	/* If "nothrow" or "tail" is set, then there is no more to do */
	if((flags & (JIT_CALL_NOTHROW | JIT_CALL_TAIL)) != 0)
	{
		return 1;
	}

	/* This function may throw an exception */
	func->builder->may_throw = 1;

#if JIT_APPLY_BROKEN_FRAME_BUILTINS != 0
	{
		jit_value_t eh_frame_info;
		jit_type_t params[2];

		/* Get the value that holds the exception frame information */
		if((eh_frame_info = func->builder->eh_frame_info) == 0)
		{
			type = jit_type_create_struct(0, 0, 0);
			if(!type)
			{
				return 0;
			}
			jit_type_set_size_and_alignment
				(type, sizeof(struct jit_backtrace), sizeof(void *));
			eh_frame_info = jit_value_create(func, type);
			jit_type_free(type);
			if(!eh_frame_info)
			{
				return 0;
			}
			func->builder->eh_frame_info = eh_frame_info;
		}

		/* Output an instruction to load the "pc" into a value */
		args[1] = jit_value_create(func, jit_type_void_ptr);
		if(!(args[1]))
		{
			return 0;
		}
		insn = _jit_block_add_insn(func->builder->current_block);
		if(!insn)
		{
			return 0;
		}
		jit_value_ref(func, args[1]);
		insn->opcode = JIT_OP_LOAD_PC;
		insn->dest = args[1];

		/* Load the address of "eh_frame_info" into another value */
		args[0] = jit_insn_address_of(func, eh_frame_info);
		if(!(args[0]))
		{
			return 0;
		}

		/* Create a signature for the prototype "void (void *, void *)" */
		params[0] = jit_type_void_ptr;
		params[1] = jit_type_void_ptr;
		type = jit_type_create_signature
			(jit_abi_cdecl, jit_type_void, params, 2, 1);
		if(!type)
		{
			return 0;
		}

		/* Call the "_jit_backtrace_push" function */
		jit_insn_call_native
			(func, "_jit_backtrace_push",
			 (void *)_jit_backtrace_push, type, args, 2, JIT_CALL_NOTHROW);
		jit_type_free(type);
	}
#endif

	/* Update the "catch_pc" value to reflect the current context */
	if(func->builder->setjmp_value != 0)
	{
		args[0] = jit_value_create(func, jit_type_void_ptr);
		if(!(args[0]))
		{
			return 0;
		}
		insn = _jit_block_add_insn(func->builder->current_block);
		if(!insn)
		{
			return 0;
		}
		jit_value_ref(func, args[0]);
		insn->opcode = JIT_OP_LOAD_PC;
		insn->dest = args[0];
		if(!jit_insn_store_relative
			(func, jit_insn_address_of(func, func->builder->setjmp_value),
			 jit_jmp_catch_pc_offset, args[0]))
		{
			return 0;
		}
	}

	/* We are now ready to make the actual function call */
	return 1;
#else /* JIT_BACKEND_INTERP */
	/* The interpreter handles exception frames for us */
	if((flags & (JIT_CALL_NOTHROW | JIT_CALL_TAIL)) == 0)
	{
		func->builder->may_throw = 1;
	}
	return 1;
#endif
}

/*
 * Restore the exception handling frame after a function call.
 */
static int restore_eh_frame_after_call(jit_function_t func, int flags)
{
#if !defined(JIT_BACKEND_INTERP)
	jit_value_t value;

	/* If the "nothrow", "noreturn", or "tail" flags are set, then we
	   don't need to worry about this */
	if((flags & (JIT_CALL_NOTHROW | JIT_CALL_NORETURN | JIT_CALL_TAIL)) != 0)
	{
		return 1;
	}

#if JIT_APPLY_BROKEN_FRAME_BUILTINS != 0
	{
		jit_type_t type;

		/* Create the signature prototype "void (void)" */
		type = jit_type_create_signature
			(jit_abi_cdecl, jit_type_void, 0, 0, 0);
		if(!type)
		{
			return 0;
		}

		/* Call the "_jit_backtrace_pop" function */
		jit_insn_call_native
			(func, "_jit_backtrace_pop",
			 (void *)_jit_backtrace_pop, type, 0, 0, JIT_CALL_NOTHROW);
		jit_type_free(type);
	}
#endif

	/* Clear the "catch_pc" value for the current context */
	if(func->builder->setjmp_value != 0)
	{
		value = jit_value_create_nint_constant(func, jit_type_void_ptr, 0);
		if(!value)
		{
			return 0;
		}
		if(!jit_insn_store_relative
			(func, jit_insn_address_of(func, func->builder->setjmp_value),
			 jit_jmp_catch_pc_offset, value))
		{
			return 0;
		}
	}

	/* Everything is back to where it should be */
	return 1;
#else /* JIT_BACKEND_INTERP */
	/* The interpreter handles exception frames for us */
	return 1;
#endif
}

/*
 * Determine if two signatures are identical for the purpose of tail calls.
 */
static int signature_identical(jit_type_t type1, jit_type_t type2)
{
	unsigned int param;

	/* Handle the easy case first */
	if(type1 == type2)
	{

libjit/jit/jit-insn.c  view on Meta::CPAN

	unsigned int arg_num;

	/* If we are performing a tail call, then duplicate the argument
	   values so that we don't accidentally destroy parameters in
	   situations like func(x, y) -> func(y, x) */
	if((flags & JIT_CALL_TAIL) != 0 && num_args > 0)
	{
		new_args = (jit_value_t *)alloca(sizeof(jit_value_t) * num_args);
		for(arg_num = 0; arg_num < num_args; ++arg_num)
		{
			value = args[arg_num];
			if(value && value->is_parameter)
			{
				value = jit_insn_dup(func, value);
				if(!value)
				{
					return 0;
				}
			}
			new_args[arg_num] = value;
		}
		args = new_args;
	}

	/* If we are performing a tail call, then store back to our own parameters */
	if((flags & JIT_CALL_TAIL) != 0)
	{
		for(arg_num = 0; arg_num < num_args; ++arg_num)
		{
			if(!jit_insn_store(func, jit_value_get_param(func, arg_num),
							   args[arg_num]))
			{
				return 0;
			}
		}
		*struct_return = 0;
		return 1;
	}

	/* Let the back end do the work */
	return _jit_create_call_setup_insns
		(func, signature, args, num_args,
		 is_nested, nesting_level, struct_return, flags);
}

static jit_value_t
handle_return(jit_function_t func,
	      jit_type_t signature,
	      int flags, int is_nested,
	      jit_value_t *args, unsigned int num_args,
	      jit_value_t return_value)
{
	/* If the function does not return, then end the current block.
	   The next block does not have "entered_via_top" set so that
	   it will be eliminated during later code generation */
	if((flags & (JIT_CALL_NORETURN | JIT_CALL_TAIL)) != 0)
	{
		func->builder->current_block->ends_in_dead = 1;
	}

	/* If the function may throw an exceptions then end the current
	   basic block to account for exceptional control flow */
	if((flags & JIT_CALL_NOTHROW) == 0)
	{
		if(!jit_insn_new_block(func))
		{
			return 0;
		}
	}

	/* Create space for the return value, if we don't already have one */
	if(!return_value)
	{
		return_value = jit_value_create(func, jit_type_get_return(signature));
		if(!return_value)
		{
			return 0;
		}
	}

	/* Create the instructions necessary to move the return value into place */
	if((flags & JIT_CALL_TAIL) == 0)
	{
		if(!_jit_create_call_return_insns(func,
						  signature,
						  args, num_args,
						  return_value,
						  is_nested))
		{
			return 0;
		}
	}

	/* Restore exception frame information after the call */
	if(!restore_eh_frame_after_call(func, flags))
	{
		return 0;
	}

	/* Return the value containing the result to the caller */
	return return_value;
}

/*@
 * @deftypefun jit_value_t jit_insn_call (jit_function_t @var{func}, const char *@var{name}, jit_function_t @var{jit_func}, jit_type_t @var{signature}, jit_value_t *@var{args}, unsigned int @var{num_args}, int @var{flags})
 * Call the function @var{jit_func}, which may or may not be translated yet.
 * The @var{name} is for diagnostic purposes only, and can be NULL.
 *
 * If @var{signature} is NULL, then the actual signature of @var{jit_func}
 * is used in its place.  This is the usual case.  However, if the function
 * takes a variable number of arguments, then you may need to construct
 * an explicit signature for the non-fixed argument values.
 *
 * The @var{flags} parameter specifies additional information about the
 * type of call to perform:
 *
 * @table @code
 * @vindex JIT_CALL_NOTHROW
 * @item JIT_CALL_NOTHROW
 * The function never throws exceptions.
 *
 * @vindex JIT_CALL_NORETURN
 * @item JIT_CALL_NORETURN
 * The function will never return directly to its caller.  It may however
 * return to the caller indirectly by throwing an exception that the
 * caller catches.
 *
 * @vindex JIT_CALL_TAIL
 * @item JIT_CALL_TAIL
 * Apply tail call optimizations, as the result of this function
 * call will be immediately returned from the containing function.
 * Tail calls are only appropriate when the signature of the called
 * function matches the callee, and none of the parameters point
 * to local variables.
 * @end table
 *
 * If @var{jit_func} has already been compiled, then @code{jit_insn_call}
 * may be able to intuit some of the above flags for itself.  Otherwise
 * it is up to the caller to determine when the flags may be appropriate.
 * @end deftypefun
@*/
jit_value_t jit_insn_call
	(jit_function_t func, const char *name, jit_function_t jit_func,
	 jit_type_t signature, jit_value_t *args, unsigned int num_args, int flags)
{
	int is_nested;
	int nesting_level;
	jit_function_t temp_func;
	jit_value_t *new_args;
	jit_value_t return_value;
	jit_insn_t insn;
	jit_label_t entry_point;
	jit_label_t label_end;

	/* Bail out if there is something wrong with the parameters */
	if(!_jit_function_ensure_builder(func) || !jit_func)
	{
		return 0;
	}

	/* Get the default signature from "jit_func" */
	if(!signature)
	{
		signature = jit_func->signature;
	}

	/* Verify that tail calls are possible to the destination */
	if((flags & JIT_CALL_TAIL) != 0)
	{
		if(func->nested_parent || jit_func->nested_parent)
		{
			/* Cannot use tail calls with nested function calls */
			flags &= ~JIT_CALL_TAIL;
		}
		else if(!signature_identical(signature, func->signature))
		{
			/* The signatures are not the same, so tail calls not allowed */
			flags &= ~JIT_CALL_TAIL;
		}
	}

	/* Determine the nesting relationship with the current function */
	if(jit_func->nested_parent)
	{
		is_nested = 1;
		if(jit_func->nested_parent == func)
		{
			/* We are calling one of our children */
			nesting_level = -1;
		}
		else if(jit_func->nested_parent == func->nested_parent)
		{
			/* We are calling one of our direct siblings */
			nesting_level = 0;
		}
		else
		{
			/* Search up to find the actual nesting level */
			temp_func = func->nested_parent;
			nesting_level = 1;
			while(temp_func != 0 && temp_func != jit_func)
			{
				++nesting_level;
				temp_func = temp_func->nested_parent;
			}
		}
	}
	else
	{
		is_nested = 0;
		nesting_level = 0;
	}

	/* Convert the arguments to the actual parameter types */
	if(num_args > 0)
	{
		new_args = (jit_value_t *)alloca(sizeof(jit_value_t) * num_args);
		if(!convert_call_parameters(func, signature, args, num_args, new_args))
		{
			return 0;
		}
	}
	else
	{
		new_args = args;
	}

	/* Intuit additional flags from "jit_func" if it was already compiled */
	if(func->no_throw)
	{
		flags |= JIT_CALL_NOTHROW;
	}
	if(func->no_return)
	{
		flags |= JIT_CALL_NORETURN;
	}

	/* Set up exception frame information for the call */
	if(!setup_eh_frame_for_call(func, flags))
	{
		return 0;
	}

	/* Create the instructions to push the parameters onto the stack */
	if(!create_call_setup_insns
			(func, jit_func, signature, new_args, num_args,
			 is_nested, nesting_level, &return_value, flags))
	{
		return 0;
	}

	/* Output the "call" instruction */
	if((flags & JIT_CALL_TAIL) != 0 && func == jit_func)
	{
		/* We are performing a tail call to ourselves, which we can
		   turn into an unconditional branch back to our entry point */
		entry_point = jit_label_undefined;
		label_end = jit_label_undefined;
		if(!jit_insn_branch(func, &entry_point))
		{
			return 0;
		}
		if(!jit_insn_label(func, &entry_point))
		{
			return 0;
		}
		if(!jit_insn_label(func, &label_end))
		{
			return 0;
		}
		if(!jit_insn_move_blocks_to_start(func, entry_point, label_end))
		{
			return 0;
		}
	}
	else
	{
		/* Functions that call out are not leaves */
		func->builder->non_leaf = 1;

		/* Performing a regular call, or a tail call to someone else */
		insn = _jit_block_add_insn(func->builder->current_block);
		if(!insn)
		{
			return 0;
		}
		if((flags & JIT_CALL_TAIL) != 0)
		{
			func->builder->has_tail_call = 1;

libjit/jit/jit-insn.c  view on Meta::CPAN

				if(!create_note
					(func, JIT_OP_RETURN_SMALL_STRUCT, value,
				     jit_value_create_nint_constant
						(func, jit_type_nint,
						 (jit_nint)(jit_type_get_size(type)))))
				{
					break;
				}
			}
		}
		break;

		default:
		{
			/* Everything else uses the normal return logic */
			return jit_insn_return
				(func, jit_insn_load_relative(func, value, 0, type));
		}
		/* Not reached */
	}

	/* Mark the current block as "ends in dead" */
	func->builder->current_block->ends_in_dead = 1;

	/* Start a new block just after the "return" instruction */
	return jit_insn_new_block(func);
}

/*@
 * @deftypefun int jit_insn_default_return (jit_function_t @var{func})
 * Add an instruction to return a default value if control reaches this point.
 * This is typically used at the end of a function to ensure that all paths
 * return to the caller.  Returns zero if out of memory, 1 if a default
 * return was added, and 2 if a default return was not needed.
 *
 * Note: if this returns 1, but the function signature does not return
 * @code{void}, then it indicates that a higher-level language error
 * has occurred and the function should be abandoned.
 * @end deftypefun
@*/
int jit_insn_default_return(jit_function_t func)
{
	/* Ensure that we have a builder for this function */
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}

	/* If the last block ends in an unconditional branch, or is dead,
	   then we don't need to add a default return */
	if(jit_block_current_is_dead(func))
	{
		return 2;
	}

	/* Add a simple "void" return to terminate the function */
	return jit_insn_return(func, 0);
}

/*@
 * @deftypefun int jit_insn_throw (jit_function_t @var{func}, jit_value_t @var{value})
 * Throw a pointer @var{value} as an exception object.  This can also
 * be used to "rethrow" an object from a catch handler that is not
 * interested in handling the exception.
 * @end deftypefun
@*/
int jit_insn_throw(jit_function_t func, jit_value_t value)
{
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	func->builder->may_throw = 1;
	func->builder->non_leaf = 1;	/* May have to call out to throw */
	if(!create_unary_note(func, JIT_OP_THROW, value))
	{
		return 0;
	}
	func->builder->current_block->ends_in_dead = 1;
	return jit_insn_new_block(func);
}

/*@
 * @deftypefun jit_value_t jit_insn_get_call_stack (jit_function_t @var{func})
 * Get an object that represents the current position in the code,
 * and all of the functions that are currently on the call stack.
 * This is equivalent to calling @code{jit_exception_get_stack_trace},
 * and is normally used just prior to @code{jit_insn_throw} to record
 * the location of the exception that is being thrown.
 * @end deftypefun
@*/
jit_value_t jit_insn_get_call_stack(jit_function_t func)
{
	jit_type_t type;
	jit_value_t value;

	/* Create a signature prototype for "void *()" */
	type = jit_type_create_signature
		(jit_abi_cdecl, jit_type_void_ptr, 0, 0, 1);
	if(!type)
	{
		return 0;
	}

	/* Call "jit_exception_get_stack_trace" to obtain the stack trace */
	value = jit_insn_call_native
		(func, "jit_exception_get_stack_trace",
		 (void *)jit_exception_get_stack_trace, type, 0, 0, 0);

	/* Clean up and exit */
	jit_type_free(type);
	return value;
}

/*@
 * @deftypefun jit_value_t jit_insn_thrown_exception (jit_function_t @var{func})
 * Get the value that holds the most recent thrown exception.  This is
 * typically used in @code{catch} clauses.
 * @end deftypefun
@*/
jit_value_t jit_insn_thrown_exception(jit_function_t func)
{
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	if(!(func->builder->thrown_exception))
	{
		func->builder->thrown_exception =
			jit_value_create(func, jit_type_void_ptr);
	}
	return func->builder->thrown_exception;
}

/*
 * Initialize the "setjmp" setup block that is needed to catch exceptions
 * thrown back to this level of execution.  The block looks like this:
 *
 *		jit_jmp_buf jbuf;
 *		void *catcher;
 *
 *      _jit_unwind_push_setjmp(&jbuf);
 *      if(setjmp(&jbuf.buf))
 *		{
 *			catch_pc = jbuf.catch_pc;
 *			if(catch_pc)
 *			{
 *				jbuf.catch_pc = 0;
 *				goto *catcher;
 *			}
 *			else
 *			{
 *				_jit_unwind_pop_and_rethrow();
 *			}
 *		}
 *
 * The field "jbuf.catch_pc" will be set to the address of the relevant
 * "catch" block just before a subroutine call that may involve exceptions.
 * It will be reset to NULL after such subroutine calls.
 *
 * Native back ends are responsible for outputting a call to the function
 * "_jit_unwind_pop_setjmp()" just before "return" instructions if the
 * "has_try" flag is set on the function.
 */
static int initialize_setjmp_block(jit_function_t func)
{
#if !defined(JIT_BACKEND_INTERP)
	jit_label_t start_label = jit_label_undefined;
	jit_label_t end_label = jit_label_undefined;
	jit_label_t code_label = jit_label_undefined;
	jit_label_t rethrow_label = jit_label_undefined;
	jit_type_t type;
	jit_value_t args[2];
	jit_value_t value;

	/* Bail out if we have already done this before */
	if(func->builder->setjmp_value)
	{
		return 1;
	}
	func->builder->catcher_label = jit_label_undefined;

	/* Force the start of a new block to mark the start of the init code */
	if(!jit_insn_label(func, &start_label))
	{
		return 0;
	}

	/* Create a value to hold an item of type "jit_jmp_buf" */
	type = jit_type_create_struct(0, 0, 1);
	if(!type)
	{
		return 0;
	}
	jit_type_set_size_and_alignment
		(type, sizeof(jit_jmp_buf), JIT_BEST_ALIGNMENT);
	if((func->builder->setjmp_value = jit_value_create(func, type)) == 0)
	{
		jit_type_free(type);
		return 0;
	}
	jit_type_free(type);

	/* Call "_jit_unwind_push_setjmp" with "&setjmp_value" as its argument */
	type = jit_type_void_ptr;
	type = jit_type_create_signature
		(jit_abi_cdecl, jit_type_void, &type, 1, 1);
	if(!type)
	{
		return 0;
	}
	args[0] = jit_insn_address_of(func, func->builder->setjmp_value);
	jit_insn_call_native
		(func, "_jit_unwind_push_setjmp",
		 (void *)_jit_unwind_push_setjmp, type, args, 1, JIT_CALL_NOTHROW);
	jit_type_free(type);

	/* Call "__sigsetjmp" or "setjmp" with "&setjmp_value" as its argument.
	   We prefer "__sigsetjmp" because it is least likely to be a macro */
#if defined(HAVE___SIGSETJMP) || defined(HAVE_SIGSETJMP)
	{
		jit_type_t params[2];
		params[0] = jit_type_void_ptr;
		params[1] = jit_type_sys_int;
		type = jit_type_create_signature
			(jit_abi_cdecl, jit_type_int, params, 2, 1);
	}
	if(!type)
	{
		return 0;
	}
	args[0] = jit_insn_address_of(func, func->builder->setjmp_value);
	args[1] = jit_value_create_nint_constant(func, jit_type_sys_int, 1);
#if defined(HAVE___SIGSETJMP)
	value = jit_insn_call_native
		(func, "__sigsetjmp", (void *)__sigsetjmp,
		 type, args, 2, JIT_CALL_NOTHROW);
#else
	value = jit_insn_call_native
		(func, "sigsetjmp", (void *)sigsetjmp,
		 type, args, 2, JIT_CALL_NOTHROW);
#endif
	jit_type_free(type);
	if(!value)
	{
		return 0;
	}
#else	/* !HAVE_SIGSETJMP */
	type = jit_type_void_ptr;
	type = jit_type_create_signature
		(jit_abi_cdecl, jit_type_int, &type, 1, 1);
	if(!type)
	{
		return 0;
	}
	args[0] = jit_insn_address_of(func, func->builder->setjmp_value);

#if defined(HAVE__SETJMP)
	value = jit_insn_call_native
		(func, "_setjmp", (void *)_setjmp, type, args, 1, JIT_CALL_NOTHROW);

#else
	value = jit_insn_call_native
		(func, "setjmp", (void *)setjmp, type, args, 1, JIT_CALL_NOTHROW);
#endif

	jit_type_free(type);
	if(!value)
	{
		return 0;
	}
#endif	/* !HAVE_SIGSETJMP */

	/* Branch to the end of the init code if "setjmp" returned zero */
	if(!jit_insn_branch_if_not(func, value, &code_label))
	{
		return 0;
	}

	/* We need a value to hold the location of the thrown exception */
	if((func->builder->thrown_pc =
			jit_value_create(func, jit_type_void_ptr)) == 0)
	{
		return 0;
	}

	/* Get the value of "catch_pc" from within "setjmp_value" and store it
	   into the current frame.  This indicates where the exception occurred */
	value = jit_insn_load_relative
		(func, jit_insn_address_of(func, func->builder->setjmp_value),
		 jit_jmp_catch_pc_offset, jit_type_void_ptr);
	if(!value)
	{
		return 0;
	}
	if(!jit_insn_store(func, func->builder->thrown_pc, value))
	{
		return 0;
	}
	if(!jit_insn_branch_if_not(func, value, &rethrow_label))
	{
		return 0;
	}

	/* Clear the original "catch_pc" value within "setjmp_value" */
	if(!jit_insn_store_relative
		(func, jit_insn_address_of(func, func->builder->setjmp_value),
		 jit_jmp_catch_pc_offset, jit_value_create_nint_constant
		 	(func, jit_type_void_ptr, 0)))
	{
		return 0;
	}

	/* Jump to this function's exception catcher */
	if(!jit_insn_branch(func, &(func->builder->catcher_label)))
	{
		return 0;
	}

	/* Mark the position of the rethrow label */
	if(!jit_insn_label(func, &rethrow_label))
	{
		return 0;
	}

	/* Call "_jit_unwind_pop_and_rethrow" to pop the current
	   "setjmp" context and then rethrow the current exception */
	type = jit_type_create_signature
		(jit_abi_cdecl, jit_type_void, 0, 0, 1);
	if(!type)
	{
		return 0;
	}
	jit_insn_call_native
		(func, "_jit_unwind_pop_and_rethrow",
		 (void *)_jit_unwind_pop_and_rethrow, type, 0, 0,
		 JIT_CALL_NOTHROW | JIT_CALL_NORETURN);
	jit_type_free(type);

	/* Insert the target to jump to the normal code. */
	if(!jit_insn_label(func, &code_label))
	{
		return 0;
	}

	/* Force the start of a new block to mark the end of the init code */
	if(!jit_insn_label(func, &end_label))
	{
		return 0;
	}

	/* Move the initialization code to the head of the function so that
	   it is performed once upon entry to the function */
	return jit_insn_move_blocks_to_start(func, start_label, end_label);
#else
	/* The interpreter doesn't need the "setjmp" setup block */
	func->builder->catcher_label = jit_label_undefined;
	return 1;
#endif
}

/*@
 * @deftypefun int jit_insn_uses_catcher (jit_function_t @var{func})
 * Notify the function building process that @var{func} contains
 * some form of @code{catch} clause for catching exceptions.  This must
 * be called before any instruction that is covered by a @code{try},
 * ideally at the start of the function output process.
 * @end deftypefun
@*/
int jit_insn_uses_catcher(jit_function_t func)
{
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	if(func->has_try)
	{
		return 1;
	}
	func->has_try = 1;
	func->builder->may_throw = 1;
	func->builder->non_leaf = 1;
	return initialize_setjmp_block(func);
}

/*@
 * @deftypefun jit_value_t jit_insn_start_catcher (jit_function_t @var{func})
 * Start the catcher block for @var{func}.  There should be exactly one
 * catcher block for any function that involves a @code{try}.  All
 * exceptions that are thrown within the function will cause control
 * to jump to this point.  Returns a value that holds the exception
 * that was thrown.
 * @end deftypefun
@*/
jit_value_t jit_insn_start_catcher(jit_function_t func)
{
	jit_value_t value;
#if !defined(JIT_BACKEND_INTERP)
	jit_value_t last_exception;
	jit_type_t type;
#endif
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	if(!jit_insn_label(func, &(func->builder->catcher_label)))
	{
		return 0;
	}
	value = jit_insn_thrown_exception(func);
	if(!value)
	{
		return 0;
	}
#if defined(JIT_BACKEND_INTERP)
	/* In the interpreter, the exception object will be on the top of
	   the operand stack when control reaches the catcher */
	if(!jit_insn_incoming_reg(func, value, 0))
	{
		return 0;
	}
#else
	type = jit_type_create_signature(jit_abi_cdecl, jit_type_void_ptr, 0, 0, 1);
	if(!type)
	{
		return 0;
	}
	last_exception = jit_insn_call_native(
		func, "jit_exception_get_last",
		(void *)jit_exception_get_last, type, 0, 0, JIT_CALL_NOTHROW);
	jit_insn_store(func, value, last_exception);
	jit_type_free(type);
#endif
	return value;
}

/*@
 * @deftypefun int jit_insn_branch_if_pc_not_in_range (jit_function_t @var{func}, jit_label_t @var{start_label}, jit_label_t @var{end_label}, jit_label_t *@var{label})
 * Branch to @var{label} if the program counter where an exception occurred
 * does not fall between @var{start_label} and @var{end_label}.
 * @end deftypefun
@*/
int jit_insn_branch_if_pc_not_in_range
	(jit_function_t func, jit_label_t start_label,
	 jit_label_t end_label, jit_label_t *label)
{
	jit_value_t value1;
	jit_value_t value2;

	/* Ensure that we have a function builder and a try block */
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	if(!(func->has_try))
	{
		return 0;
	}

	/* Flush any stack pops that were deferred previously */
	if(!jit_insn_flush_defer_pop(func, 0))
	{
		return 0;
	}

	/* Get the location where the exception occurred in this function */
#if defined(JIT_BACKEND_INTERP)
	value1 = create_dest_note
		(func, JIT_OP_LOAD_EXCEPTION_PC, jit_type_void_ptr);
#else
	value1 = func->builder->thrown_pc;
#endif
	if(!value1)
	{
		return 0;
	}

	/* Compare the location against the start and end labels */
	value2 = jit_insn_address_of_label(func, &start_label);
	if(!value2)
	{
		return 0;
	}
	if(!jit_insn_branch_if(func, jit_insn_lt(func, value1, value2), label))
	{
		return 0;
	}
	value2 = jit_insn_address_of_label(func, &end_label);
	if(!value2)
	{
		return 0;
	}
	if(!jit_insn_branch_if(func, jit_insn_ge(func, value1, value2), label))
	{
		return 0;
	}

	/* If control gets here, then we have a location match */
	return 1;
}

/*@
 * @deftypefun int jit_insn_rethrow_unhandled (jit_function_t @var{func})
 * Rethrow the current exception because it cannot be handled by
 * any of the @code{catch} blocks in the current function.
 *
 * Note: this is intended for use within catcher blocks.  It should not
 * be used to rethrow exceptions in response to programmer requests
 * (e.g. @code{throw;} in C#).  The @code{jit_insn_throw} function
 * should be used for that purpose.
 * @end deftypefun
@*/
int jit_insn_rethrow_unhandled(jit_function_t func)
{
	jit_value_t value;
#if !defined(JIT_BACKEND_INTERP)
	jit_type_t type;
#endif

	/* Ensure that we have a function builder */
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}

	/* Get the current exception value to be thrown */
	value = jit_insn_thrown_exception(func);
	if(!value)
	{
		return 0;
	}

#if defined(JIT_BACKEND_INTERP)

	/* Rethrow the current exception (interpreter version) */
	if(!create_unary_note(func, JIT_OP_RETHROW, value))
	{
		return 0;
	}

#else /* !JIT_BACKEND_INTERP */

	/* Call "_jit_unwind_pop_setjmp" to remove the current exception catcher */
	if(!_jit_function_ensure_builder(func))
	{
		return 0;
	}
	type = jit_type_create_signature
		(jit_abi_cdecl, jit_type_void, 0, 0, 1);
	if(!type)
	{
		return 0;
	}
	jit_insn_call_native
		(func, "_jit_unwind_pop_setjmp",
		 (void *)_jit_unwind_pop_setjmp, type, 0, 0, JIT_CALL_NOTHROW);
	jit_type_free(type);

	/* Call the "jit_exception_throw" function to effect the rethrow */
	type = jit_type_void_ptr;
	type = jit_type_create_signature
		(jit_abi_cdecl, jit_type_void, &type, 1, 1);
	if(!type)
	{
		return 0;
	}
	jit_insn_call_native
		(func, "jit_exception_throw",
		 (void *)jit_exception_throw, type, &value, 1,
		 JIT_CALL_NOTHROW | JIT_CALL_NORETURN);
	jit_type_free(type);

#endif /* !JIT_BACKEND_INTERP */

	/* The current block ends in dead and we need to start a new block */
	func->builder->current_block->ends_in_dead = 1;
	return jit_insn_new_block(func);
}

/*@
 * @deftypefun int jit_insn_start_finally (jit_function_t @var{func}, jit_label_t *@var{finally_label})
 * Start a @code{finally} clause.
 * @end deftypefun
@*/
int jit_insn_start_finally(jit_function_t func, jit_label_t *finally_label)
{
	if(!jit_insn_label(func, finally_label))
	{
		return 0;
	}
	return create_noarg_note(func, JIT_OP_ENTER_FINALLY);
}

/*@
 * @deftypefun int jit_insn_return_from_finally (jit_function_t @var{func})
 * Return from the @code{finally} clause to where it was called from.
 * This is usually the last instruction in a @code{finally} clause.
 * @end deftypefun
@*/
int jit_insn_return_from_finally(jit_function_t func)
{
	/* Flush any deferred stack pops before we return */
	if(!jit_insn_flush_defer_pop(func, 0))
	{
		return 0;
	}

	/* Mark the end of the "finally" clause */
	if(!create_noarg_note(func, JIT_OP_LEAVE_FINALLY))
	{
		return 0;
	}

	/* The current block ends in a dead instruction */
	func->builder->current_block->ends_in_dead = 1;

	/* Create a new block for the following code */
	return jit_insn_new_block(func);
}

/*@
 * @deftypefun int jit_insn_call_finally (jit_function_t @var{func}, jit_label_t *@var{finally_label})
 * Call a @code{finally} clause.
 * @end deftypefun
@*/
int jit_insn_call_finally(jit_function_t func, jit_label_t *finally_label)
{
	jit_insn_t insn;



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