Initial import of gofrontend repository.

Immediately preceding revision history may be found at
svn://gcc.gnu.org/svn/gcc/branches/gccgo, in the gcc/go and libgo
subdirectories.
diff --git a/libgo/runtime/go-caller.c b/libgo/runtime/go-caller.c
new file mode 100644
index 0000000..2df6d5b
--- /dev/null
+++ b/libgo/runtime/go-caller.c
@@ -0,0 +1,40 @@
+/* go-caller.c -- runtime.Caller for Go.
+
+   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.  */
+
+/* Implement runtime.Caller.  */
+
+#include <stdint.h>
+
+#include "go-string.h"
+
+/* The values returned by runtime.Caller.  */
+
+struct caller_ret
+{
+  uintptr_t pc;
+  const struct __go_string *file;
+  int line;
+  _Bool ok;
+};
+
+/* Implement runtime.Caller.  */
+
+struct caller_ret Caller (int n) asm ("libgo_runtime.runtime.Caller");
+
+struct caller_ret
+Caller (int n __attribute__ ((unused)))
+{
+  struct caller_ret ret;
+
+  /* A proper implementation needs to dig through the debugging
+     information.  */
+  ret.pc = (uint64_t) (uintptr_t) __builtin_return_address (1);
+  ret.file = NULL;
+  ret.line = 0;
+  ret.ok = 0;
+
+  return ret;
+}