[PATCH] toplev: avoid recursive emergency_dump_function

[Alexander Monakov <amonakov at ispras dot ru>]

Hi,

Segher pointed out on IRC that ICE reporting with dumps enabled got worse:
if emergency_dump_function itself leads to an ICE (e.g. by segfaulting),
nested ICE reporting will invoke emergency_dump_function in exactly the
same context, but not only would we uselessly announce current pass again,
this time around the second SIGSEGV will just terminate cc1 because the
signal handler is unregistered (so we won't print the backtrace).  Sorry
for not really considering the implications when submitting that patch.

Solve this by substituting the callback for global_dc->internal_error;
this avoids invoking emergency_dump_function, and also gives a
convenient point to flush the dump file.  OK to apply?

	* topvel.c (dumpfile.h): New include.
	(internal_error_reentered): New static function.  Use it...
	(internal_error_function): ...here to handle reentered internal_error.

diff --git a/gcc/toplev.c b/gcc/toplev.c
index e6c69a4..67254fb 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -80,6 +80,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "hsa-common.h"
 #include "edit-context.h"
 #include "tree-pass.h"
+#include "dumpfile.h"

 #if defined(DBX_DEBUGGING_INFO) || defined(XCOFF_DEBUGGING_INFO)
 #include "dbxout.h"
@@ -1064,11 +1065,22 @@ open_auxiliary_file (const char *ext)
   return file;
 }

+/* Alternative diagnostics callback for reentered ICE reporting.  */
+
+static void
+internal_error_reentered (diagnostic_context *, const char *, va_list *)
+{
+  /* Flush the dump file if emergency_dump_function itself caused an ICE.  */
+  if (dump_file)
+    fflush (dump_file);
+}
+
 /* Auxiliary callback for the diagnostics code.  */

 static void
 internal_error_function (diagnostic_context *, const char *, va_list *)
 {
+  global_dc->internal_error = internal_error_reentered;
   warn_if_plugins ();
   emergency_dump_function ();
 }