[Darwin] Improve Objective-C NeXT ABI version check.

We were missing a check for the case that user's ABI was > 2 and the
codegen was for 64 bit.

gcc/ChangeLog:

2019-10-09  Iain Sandoe  <iain@sandoe.co.uk>

	* config/darwin.c (darwin_override_options): Make the check for
	Objective-C ABI version more specific for 64bit code.

From-SVN: r276768

gcc/ChangeLog

 2019-10-09  Iain Sandoe  <iain@sandoe.co.uk>
 
+	* config/darwin.c (darwin_override_options): Make the check for
+	Objective-C ABI version more specific for 64bit code.
+
+2019-10-09  Iain Sandoe  <iain@sandoe.co.uk>
+
 	* config/darwin.c (machopic_indirect_data_reference): Set flag to
 	indicate that the new symbol is an indirection.
 	(machopic_indirect_call_target): Likewise.

gcc/config/darwin.c

@@ -3114,18 +3114,19 @@ darwin_override_options (void)
 				: (generating_for_darwin_version >= 9) ? 1
 								       : 0);
 
-  /* Objective-C family ABI 2 is only valid for next/m64 at present.  */
   if (global_options_set.x_flag_objc_abi && flag_next_runtime)
     {
-      if (TARGET_64BIT && global_options.x_flag_objc_abi < 2)
-	error_at (UNKNOWN_LOCATION, "%<-fobjc-abi-version%> must be greater"
-				    " than or equal to 2 for %<-m64%> targets"
-				    " with %<-fnext-runtime%>");
-      if (!TARGET_64BIT && global_options.x_flag_objc_abi >= 2)
-	error_at (UNKNOWN_LOCATION, "%<-fobjc-abi-version%> %d is not"
-				    " supported on %<-m32%> targets with"
-				    " %<-fnext-runtime%>",
-				    global_options.x_flag_objc_abi);
+      if (TARGET_64BIT && global_options.x_flag_objc_abi != 2)
+	/* The Objective-C family ABI 2 is the only valid version NeXT/m64.  */
+	error_at (UNKNOWN_LOCATION,
+		  "%<-fobjc-abi-version%> 2 must be used for 64 bit targets"
+		  " with %<-fnext-runtime%>");
+      else if (!TARGET_64BIT && global_options.x_flag_objc_abi >= 2)
+	/* ABI versions 0 and 1 are the only valid versions NeXT/m32.  */
+	error_at (UNKNOWN_LOCATION,
+		  "%<-fobjc-abi-version%> %d is not supported for 32 bit"
+		  " targets with %<-fnext-runtime%>",
+		  global_options.x_flag_objc_abi);
     }
 
   /* Don't emit DWARF3/4 unless specifically selected.  This is a