gcc/libgo/runtime/go-can-convert-interface.c
Ian Lance Taylor f8d9fa9e80 libgo, compiler: Upgrade libgo to Go 1.4, except for runtime.
This upgrades all of libgo other than the runtime package to
the Go 1.4 release.  In Go 1.4 much of the runtime was
rewritten into Go.  Merging that code will take more time and
will not change the API, so I'm putting it off for now.

There are a few runtime changes anyhow, to accomodate other
packages that rely on minor modifications to the runtime
support.

The compiler changes slightly to add a one-bit flag to each
type descriptor kind that is stored directly in an interface,
which for gccgo is currently only pointer types.  Another
one-bit flag (gcprog) is reserved because it is used by the gc
compiler, but gccgo does not currently use it.

There is another error check in the compiler since I ran
across it during testing.

gotools/:
	* Makefile.am (go_cmd_go_files): Sort entries.  Add generate.go.
	* Makefile.in: Rebuild.

From-SVN: r219627
2015-01-15 00:27:56 +00:00

79 lines
2.1 KiB
C

/* go-can-convert-interface.c -- can we convert to an interface?
Copyright 2009 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file. */
#include "runtime.h"
#include "go-assert.h"
#include "go-string.h"
#include "go-type.h"
#include "interface.h"
/* Return whether we can convert from the type in FROM_DESCRIPTOR to
the interface in TO_DESCRIPTOR. This is used for type
switches. */
_Bool
__go_can_convert_to_interface (
const struct __go_type_descriptor *to_descriptor,
const struct __go_type_descriptor *from_descriptor)
{
const struct __go_interface_type *to_interface;
int to_method_count;
const struct __go_interface_method *to_method;
const struct __go_uncommon_type *from_uncommon;
int from_method_count;
const struct __go_method *from_method;
int i;
/* In a type switch FROM_DESCRIPTOR can be NULL. */
if (from_descriptor == NULL)
return 0;
__go_assert ((to_descriptor->__code & GO_CODE_MASK) == GO_INTERFACE);
to_interface = (const struct __go_interface_type *) to_descriptor;
to_method_count = to_interface->__methods.__count;
to_method = ((const struct __go_interface_method *)
to_interface->__methods.__values);
from_uncommon = from_descriptor->__uncommon;
if (from_uncommon == NULL)
{
from_method_count = 0;
from_method = NULL;
}
else
{
from_method_count = from_uncommon->__methods.__count;
from_method = ((const struct __go_method *)
from_uncommon->__methods.__values);
}
for (i = 0; i < to_method_count; ++i)
{
while (from_method_count > 0
&& (!__go_ptr_strings_equal (from_method->__name,
to_method->__name)
|| !__go_ptr_strings_equal (from_method->__pkg_path,
to_method->__pkg_path)))
{
++from_method;
--from_method_count;
}
if (from_method_count == 0)
return 0;
if (!__go_type_descriptors_equal (from_method->__mtype,
to_method->__type))
return 0;
++to_method;
++from_method;
--from_method_count;
}
return 1;
}