--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/go/gofrontend/go-diagnostics.cc	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,177 @@
+// go-diagnostics.cc -- Go error/warning diagnostics utilities.
+
+// Copyright 2016 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 "go-diagnostics.h"
+
+static std::string
+mformat_value()
+{
+  return std::string(xstrerror(errno));
+}
+
+// Rewrite a format string to expand any extensions not
+// supported by sprintf(). See comments in go-diagnostics.h
+// for list of supported format specifiers.
+
+static std::string
+expand_format(const char* fmt)
+{
+  std::stringstream ss;
+  for (const char* c = fmt; *c; ++c)
+    {
+      if (*c != '%')
+        {
+          ss << *c;
+          continue;
+        }
+      c++;
+      switch (*c)
+        {
+          case '\0':
+            {
+              // malformed format string
+              go_unreachable();
+            }
+          case '%':
+            {
+              ss << "%";
+              break;
+            }
+          case 'm':
+            {
+              ss << mformat_value();
+              break;
+            }
+          case '<':
+            {
+              ss << go_open_quote();
+              break;
+            }
+          case '>':
+            {
+              ss << go_close_quote();
+              break;
+            }
+          case 'q':
+            {
+              ss << go_open_quote();
+              c++;
+              if (*c == 'm')
+                {
+                  ss << mformat_value();
+                }
+              else
+                {
+                  ss << "%" << *c;
+                }
+              ss << go_close_quote();
+              break;
+            }
+          default:
+            {
+              ss << "%" << *c;
+            }
+        }
+    }
+  return ss.str();
+}
+
+// Expand message format specifiers, using a combination of
+// expand_format above to handle extensions (ex: %m, %q) and vasprintf()
+// to handle regular printf-style formatting. A pragma is being used here to
+// suppress this warning:
+//
+//   warning: function ‘std::__cxx11::string expand_message(const char*, __va_list_tag*)’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
+//
+// What appears to be happening here is that the checker is deciding that
+// because of the call to vasprintf() (which has attribute gnu_printf), the
+// calling function must need to have attribute gnu_printf as well, even
+// though there is already an attribute declaration for it.
+
+static std::string
+expand_message(const char* fmt, va_list ap) GO_ATTRIBUTE_GCC_DIAG(1,0);
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
+
+static std::string
+expand_message(const char* fmt, va_list ap)
+{
+  char* mbuf = 0;
+  std::string expanded_fmt = expand_format(fmt);
+  int nwr = vasprintf(&mbuf, expanded_fmt.c_str(), ap);
+  if (nwr == -1)
+    {
+      // memory allocation failed
+      go_be_error_at(Linemap::unknown_location(),
+                     "memory allocation failed in vasprintf");
+      go_assert(0);
+    }
+  std::string rval = std::string(mbuf);
+  free(mbuf);
+  return rval;
+}
+
+#pragma GCC diagnostic pop
+
+static const char* cached_open_quote = NULL;
+static const char* cached_close_quote = NULL;
+
+const char*
+go_open_quote()
+{
+  if (cached_open_quote == NULL)
+    go_be_get_quotechars(&cached_open_quote, &cached_close_quote);
+  return cached_open_quote;
+}
+
+const char*
+go_close_quote()
+{
+  if (cached_close_quote == NULL)
+    go_be_get_quotechars(&cached_open_quote, &cached_close_quote);
+  return cached_close_quote;
+}
+
+void
+go_error_at(const Location location, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_error_at(location, expand_message(fmt, ap));
+  va_end(ap);
+}
+
+void
+go_warning_at(const Location location, int opt, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_warning_at(location, opt, expand_message(fmt, ap));
+  va_end(ap);
+}
+
+void
+go_fatal_error(const Location location, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_fatal_error(location, expand_message(fmt, ap));
+  va_end(ap);
+}
+
+void
+go_inform(const Location location, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_inform(location, expand_message(fmt, ap));
+  va_end(ap);
+}