Check in a pristine copy of GCC 4.8.1.

The copy of GCC that we use for Android is still not working for
mingw. Rather than finding all the differences that have crept into
our GCC, just check in a copy from
ftp://ftp.gnu.org/gnu/gcc/gcc-4.9.3/gcc-4.8.1.tar.bz2.

GCC 4.8.1 was chosen because it is what we have been using for mingw
thus far, and the emulator doesn't yet work when upgrading to 4.9.

Bug: http://b/26523949
Change-Id: Iedc0f05243d4332cc27ccd46b8a4b203c88dcaa3

1 files changed, 78 insertions, 0 deletions

diff --git a/gcc-4.8.1/libgo/runtime/go-can-convert-interface.c b/gcc-4.8.1/libgo/runtime/go-can-convert-interface.c
new file mode 100644
index 000000000..4de558077
--- /dev/null
+++ b/gcc-4.8.1/libgo/runtime/go-can-convert-interface.c
@@ -0,0 +1,78 @@
+/* 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_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;
+}