Stop the assembler from complaining that the input and output files are the same, if neither of them are regular files.

	PR 25572
	* as.c (main): Allow matching input and outputs when they are
	not regular files.

2 files changed, 13 insertions, 1 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index f81ec12..e2984b5 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-06  Nick Clifton  <nickc@redhat.com>
+
+	PR 25572
+	* as.c (main): Allow matching input and outputs when they are
+	not regular files.
+
 2020-03-06  Jan Beulich  <jbeulich@suse.com>
 
 	* config/tc-i386.c (match_mem_size): Generalize broadcast special
diff --git a/gas/as.c b/gas/as.c
index d8d20cc..51bb721 100644
--- a/gas/as.c
+++ b/gas/as.c
@@ -1290,7 +1290,13 @@ main (int argc, char ** argv)
 	      /* Different files may have the same inode number if they
 		 reside on different devices, so check the st_dev field as
 		 well.  */
-	      && sib.st_dev == sob.st_dev)
+	      && sib.st_dev == sob.st_dev
+	      /* PR 25572: Only check regular files.  Devices, sockets and so
+		 on might actually work as both input and output.  Plus there
+		 is a use case for using /dev/null as both input and output
+		 when checking for command line option support in a script:
+		   as --foo /dev/null -o /dev/null; if $? then ...  */
+	      && S_ISREG (sib.st_mode))
 	    {
 	      const char *saved_out_file_name = out_file_name;