--- a/gcc/plugin.c	Thu Oct 25 07:37:49 2018 +0900
+++ b/gcc/plugin.c	Thu Feb 13 11:34:05 2020 +0900
@@ -1,5 +1,5 @@
 /* Support for GCC plugin mechanism.
-   Copyright (C) 2009-2018 Free Software Foundation, Inc.
+   Copyright (C) 2009-2020 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -231,7 +231,7 @@
     {
       plugin = (struct plugin_name_args *) *slot;
       if (strcmp (plugin->full_name, plugin_name))
-        error ("plugin %s was specified with different paths:\n%s\n%s",
+	error ("plugin %qs was specified with different paths: %qs and %qs",
                plugin->base_name, plugin->full_name, plugin_name);
       return;
     }
@@ -290,7 +290,8 @@
 
   if (!key_start)
     {
-      error ("malformed option -fplugin-arg-%s (missing -<key>[=<value>])",
+      error ("malformed option %<-fplugin-arg-%s%>: "
+	     "missing %<-<key>[=<value>]%>",
              arg);
       return;
     }
@@ -353,7 +354,7 @@
       plugin->argv[plugin->argc - 1].value = value;
     }
   else
-    error ("plugin %s should be specified before -fplugin-arg-%s "
+    error ("plugin %s should be specified before %<-fplugin-arg-%s%> "
            "in the command line", name, arg);
 
   /* We don't need the plugin's name anymore. Just release it.  */
@@ -700,7 +701,7 @@
   dl_handle = dlopen (plugin->full_name, RTLD_NOW | RTLD_GLOBAL);
   if (!dl_handle)
     {
-      error ("cannot load plugin %s\n%s", plugin->full_name, dlerror ());
+      error ("cannot load plugin %s: %s", plugin->full_name, dlerror ());
       return false;
     }
 
@@ -710,17 +711,17 @@
   /* Check the plugin license.  */
   if (dlsym (dl_handle, str_license) == NULL)
     fatal_error (input_location,
-		 "plugin %s is not licensed under a GPL-compatible license\n"
-		 "%s", plugin->full_name, dlerror ());
+		 "plugin %s is not licensed under a GPL-compatible license"
+		 " %s", plugin->full_name, dlerror ());
 
-  PTR_UNION_AS_VOID_PTR (plugin_init_union) =
-      dlsym (dl_handle, str_plugin_init_func_name);
+  PTR_UNION_AS_VOID_PTR (plugin_init_union)
+    = dlsym (dl_handle, str_plugin_init_func_name);
   plugin_init = PTR_UNION_AS_CAST_PTR (plugin_init_union);
 
   if ((err = dlerror ()) != NULL)
     {
       dlclose(dl_handle);
-      error ("cannot find %s in plugin %s\n%s", str_plugin_init_func_name,
+      error ("cannot find %s in plugin %s: %s", str_plugin_init_func_name,
              plugin->full_name, err);
       return false;
     }
@@ -729,7 +730,7 @@
   if ((*plugin_init) (plugin, &gcc_version))
     {
       dlclose(dl_handle);
-      error ("fail to initialize plugin %s", plugin->full_name);
+      error ("failed to initialize plugin %s", plugin->full_name);
       return false;
     }
   /* leak dl_handle on purpose to ensure the plugin is loaded for the
@@ -1003,6 +1004,6 @@
 {
   if (!plugindir_string)
     fatal_error (input_location,
-		 "-iplugindir <dir> option not passed from the gcc driver");
+		 "%<-iplugindir%> <dir> option not passed from the gcc driver");
   return plugindir_string;
 }