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[Patch, RFC] avoid potential recursion, collect error and warning summaries.

Iain Sandoe developer@sandoe-acoustics.co.uk
Mon Feb 20 21:41:00 GMT 2012 
Hello All,

1. I have a note in a patchlet from Tristan that

as.c (close_output_file)
could cause recursion if output_file_close () calls as_fatal or xexit  
() on error conditions.

2. the [presumably intended] error reporting in write.c is unreachable  
in the general case, since write_object_file () is not called when  
there are errors.

3. There's another bit of error reporting later in as.c.

====

So this patch coalesces the error reporting, moves it to the at exit  
action, and avoids the potential recursion on close errors.

Unfortunately, it can't be lightly applied - since the reporting of  
error summary causes a lot of test-cases to need amendment.  Thus I've  
guarded that section of the code, and ports can enable it when they  
have time to go through their test-cases and amend as necessary.

thoughts?

Iain

gas:

	* write.c (write_object_file): Remove warning/error summaries.
	* as.c (TC_WANTS_ERROR_SUMMARY): New.
	(close_output_file): Allow for potential errors in the close routine.
	Report warning and error summaries here.
	(main): Don't report warnings as errors here.
	* config/obj-macho.h (TC_WANTS_ERROR_SUMMARY): Define.

Index: gas/as.c
===================================================================
RCS file: /cvs/src/src/gas/as.c,v
retrieving revision 1.101
diff -u -p -r1.101 as.c
--- gas/as.c	17 Jan 2012 00:07:03 -0000	1.101
+++ gas/as.c	20 Feb 2012 21:29:51 -0000
@@ -992,12 +992,51 @@ dump_statistics (void)
  #endif
  }

+#ifndef TC_WANTS_ERROR_SUMMARY
+#define TC_WANTS_ERROR_SUMMARY 0
+#endif
+
  static void
  close_output_file (void)
  {
-  output_file_close (out_file_name);
-  if (!keep_it)
-    unlink_if_ordinary (out_file_name);
+static int closing = 0;
+
+  /* Avoid recursion if xexit is called from output_file_close().  */
+  if (! closing)
+    {
+      int n_warns, n_errs;
+
+      closing = 1;
+      output_file_close (out_file_name);
+
+      n_warns = had_warnings ();
+      n_errs = had_errors ();
+
+      /* Do error messages by hand, to avoid recursion via  
as_fatal().  */
+      if (flag_always_generate_output
+	  && (n_errs || (n_warns && flag_fatal_warnings)))
+	/* The -Z flag indicates that an object file should be generated,
+	     regardless of warnings and errors.  */
+	fprintf (stderr, _("Summary: %d error%s, %d warning%s, "
+			   "(potentially bad) object file retained\n"),
+		 n_errs, n_errs == 1 ? "" : "s",
+		 n_warns, n_warns == 1 ? "" : "s");
+      else if (n_errs)
+        {
+          if (TC_WANTS_ERROR_SUMMARY)
+	    fprintf (stderr, _("Summary: %d error%s, %d warning%s, "
+			       "no object file generated\n"),
+		     n_errs, n_errs == 1 ? "" : "s",
+		     n_warns, n_warns == 1 ? "" : "s");
+	  unlink_if_ordinary (out_file_name);
+	}
+      else if (flag_fatal_warnings && n_warns)
+        {
+	  fprintf (stderr, _("Summary: %d warnings, and treating warnings as"
+			     " errors, no object file generated\n"), n_warns);
+	  unlink_if_ordinary (out_file_name);
+        }
+  }
  }

  /* The interface between the macro code and gas expression  
handling.  */
@@ -1294,9 +1333,6 @@ main (int argc, char ** argv)
    listing_print (listing_filename, argv_orig);
  #endif

-  if (flag_fatal_warnings && had_warnings () > 0 && had_errors () == 0)
-    as_bad (_("%d warnings, treating warnings as errors"),  
had_warnings ());
-
    if (had_errors () > 0 && ! flag_always_generate_output)
      keep_it = 0;

Index: gas/write.c
===================================================================
RCS file: /cvs/src/src/gas/write.c,v
retrieving revision 1.147
diff -u -p -r1.147 write.c
--- gas/write.c	17 Jan 2012 00:20:30 -0000	1.147
+++ gas/write.c	20 Feb 2012 21:29:52 -0000
@@ -1767,29 +1767,6 @@ write_object_file (void)
    fragS *fragP;			/* Track along all frags.  */
  #endif

-  /* Do we really want to write it?  */
-  {
-    int n_warns, n_errs;
-    n_warns = had_warnings ();
-    n_errs = had_errors ();
-    /* The -Z flag indicates that an object file should be generated,
-       regardless of warnings and errors.  */
-    if (flag_always_generate_output)
-      {
-	if (n_warns || n_errs)
-	  as_warn (_("%d error%s, %d warning%s, generating bad object file"),
-		   n_errs, n_errs == 1 ? "" : "s",
-		   n_warns, n_warns == 1 ? "" : "s");
-      }
-    else
-      {
-	if (n_errs)
-	  as_fatal (_("%d error%s, %d warning%s, no object file generated"),
-		    n_errs, n_errs == 1 ? "" : "s",
-		    n_warns, n_warns == 1 ? "" : "s");
-      }
-  }
-
    /* From now on, we don't care about sub-segments.  Build one frag  
chain
       for each segment. Linked thru fr_next.  */

Index: gas/config/obj-macho.h
===================================================================
RCS file: /cvs/src/src/gas/config/obj-macho.h,v
retrieving revision 1.9
diff -u -p -r1.9 obj-macho.h
--- gas/config/obj-macho.h	20 Feb 2012 20:11:32 -0000	1.9
+++ gas/config/obj-macho.h	20 Feb 2012 21:29:52 -0000
@@ -84,4 +84,6 @@ extern int obj_mach_o_allow_local_subtra
  #define OBJ_PROCESS_STAB(SEG,W,S,T,O,D)	 
obj_mach_o_process_stab(W,S,T,O,D)
  extern void obj_mach_o_process_stab (int, const char *,int, int, int);

+#define TC_WANTS_ERROR_SUMMARY 1
+
  #endif /* _OBJ_MACH_O_H */
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