1 files changed, 28 insertions, 8 deletions

diff --git a/gcc/config/avr/driver-avr.c b/gcc/config/avr/driver-avr.c
index dbc5043d996..75d7e6f6791 100644
--- a/gcc/config/avr/driver-avr.c
+++ b/gcc/config/avr/driver-avr.c
@@ -55,9 +55,10 @@ avr_diagnose_devicespecs_error (const char *mcu, const char *filename)
 
 /* Implement spec function `device-specs-file´.
 
-   Compose -specs=<specs-file-name>.  If everything went well then argv[0]
-   is the inflated specs directory and argv[1] is a device or core name as
-   supplied to -mmcu=*.  */
+   Compose -specs=<specs-file-name>%s.  If everything went well then argv[0]
+   is the inflated (absolute) specs directory and argv[1] is a device or
+   core name as supplied by -mmcu=*.  When building GCC the path might
+   be relative.  */
 
 const char*
 avr_devicespecs_file (int argc, const char **argv)
@@ -79,16 +80,35 @@ avr_devicespecs_file (int argc, const char **argv)
       return X_NODEVLIB;
 
     case 1:
+      if (0 == strcmp ("device-specs", argv[0]))
+        {
+          /* FIXME:  This means "device-specs%s" from avr.h:DRIVER_SELF_SPECS
+             has not been resolved to a path.  That case can occur when the
+             c++ testsuite is run from the build directory.  DejaGNU's
+             libgloss.exp:get_multilibs runs $compiler without -B, i.e.runs
+             xgcc without specifying a prefix.  Without any prefix, there is
+             no means to find out where the specs files might be located.
+             get_multilibs runs xgcc --print-multi-lib, hence we don't actually
+             need information form a specs file and may skip it here.  */
+          return X_NODEVLIB;
+        }
+
       mmcu = AVR_MMCU_DEFAULT;
       break;
 
-    case 2:
+    default:
       mmcu = argv[1];
-      break;
 
-    default:
-      error ("specified option %qs more than once", "-mmcu=");
-      return X_NODEVLIB;
+      // Allow specifying the same MCU more than once.
+
+      for (int i = 2; i < argc; i++)
+        if (0 != strcmp (mmcu, argv[i]))
+          {
+            error ("specified option %qs more than once", "-mmcu");
+            return X_NODEVLIB;
+          }
+
+      break;
     }
 
   specfile_name = concat (argv[0], dir_separator_str, "specs-", mmcu, NULL);