re PR fortran/31189 (Support backtracing for non-library errors)

	PR fortran/31189

	* runtime/backtrace.c (show_backtrace): Skip _gfortrani_handler
	when displaying backtrace.
	* runtime/compile_options.c: Include <signal.h>.
	(handler): New function.
	(set_options): Set signal handlers for backtrace.
	* libgfortran.h (handler): Add prototype.

	* invoke.texi (-fbacktrace): Document the new behaviour.

Co-Authored-By: Tobias Burnus <burnus@gcc.gnu.org>

From-SVN: r127364

gcc/fortran/ChangeLog

 2007-08-11  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
+	PR fortran/31189
+	* invoke.texi (-fbacktrace): Document the new behaviour.
+
+2007-08-11  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
+
 	PR fortran/32937
 	* trans-array.c (gfc_conv_expr_descriptor): Use
 	gfc_conv_const_charlen to generate backend_decl of right type.

gcc/fortran/invoke.texi

@@ -544,7 +544,9 @@ zero), @samp{overflow} (overflow in a floating point operation),
 @opindex @code{fbacktrace}
 @cindex backtrace
 @cindex trace
-Specify that, when a runtime error is encountered, the Fortran runtime
+Specify that, when a runtime error is encountered or a deadly signal is
+emitted (segmentation fault, illegal instruction, bus error or
+floating-point exception), the Fortran runtime
 library should output a backtrace of the error.  This option
 only has influence for compilation of the Fortran main program.
 

libgfortran/ChangeLog

 2007-08-11  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
+	    Tobias Burnus  <burnus@gcc.gnu.org>
+
+	PR fortran/31189
+	* runtime/backtrace.c (show_backtrace): Skip _gfortrani_handler
+	when displaying backtrace.
+	* runtime/compile_options.c: Include <signal.h>.
+	(handler): New function.
+	(set_options): Set signal handlers for backtrace.
+	* libgfortran.h (handler): Add prototype.
+
+2007-08-11  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	* intrinsics/string_intrinsics.c (compare_string): Return an int.
 	* libgfortran.h (compare_string): Likewise.

libgfortran/libgfortran.h

@@ -373,6 +373,9 @@ options_t;
 extern options_t options;
 internal_proto(options);
 
+extern void handler (int);
+internal_proto(handler);
+
 
 /* Compile-time options that will influence the library.  */
 

libgfortran/runtime/backtrace.c

@@ -223,7 +223,8 @@ show_backtrace (void)
 	    /* Try to recognize the internal libgfortran functions.  */
 	    if (strncasecmp (func, "*_gfortran", 10) == 0
 		|| strncasecmp (func, "_gfortran", 9) == 0
-		|| strcmp (func, "main") == 0 || strcmp (func, "_start") == 0)
+		|| strcmp (func, "main") == 0 || strcmp (func, "_start") == 0
+		|| strcmp (func, "_gfortrani_handler") == 0)
 	      continue;
 
 	    if (local_strcasestr (str[i], "libgfortran.so") != NULL

libgfortran/runtime/compile_options.c

@@ -31,10 +31,61 @@ Boston, MA 02110-1301, USA.  */
 
 #include "libgfortran.h"
 
+#ifdef HAVE_SIGNAL_H
+#include <signal.h>
+#endif
+
 
 /* Useful compile-time options will be stored in here.  */
 compile_options_t compile_options;
 
+
+/* A signal handler to allow us to output a backtrace.  */
+void
+handler (int signum)
+{
+  const char * name = NULL, * desc = NULL;
+
+  switch (signum)
+    {
+#if defined(SIGSEGV)
+      case SIGSEGV:
+	name = "SIGSEGV";
+	desc = "Segmentation fault";
+	break;
+#endif
+
+#if defined(SIGBUS)
+      case SIGBUS:
+	name = "SIGBUS";
+	desc = "Bus error";
+	break;
+#endif
+
+#if defined(SIGILL)
+      case SIGILL:
+	name = "SIGILL";
+	desc = "Illegal instruction";
+	break;
+#endif
+
+#if defined(SIGFPE)
+      case SIGFPE:
+	name = "SIGFPE";
+	desc = "Floating-point exception";
+	break;
+#endif
+    }
+
+  if (name)
+    st_printf ("\nProgram received signal %d (%s): %s.\n", signum, name, desc);
+  else
+    st_printf ("\nProgram received signal %d.\n", signum);
+
+  sys_exit (5);
+}
+
+
 /* Set the usual compile-time options.  */
 extern void set_options (int , int []);
 export_proto(set_options);
@@ -56,6 +107,31 @@ set_options (int num, int options[])
     compile_options.sign_zero = options[5];
   if (num >= 7)
     compile_options.bounds_check = options[6];
+
+  /* If backtrace is required, we set signal handlers on most common
+     signals.  */
+#if defined(HAVE_SIGNAL_H) && (defined(SIGSEGV) || defined(SIGBUS) \
+			       || defined(SIGILL) || defined(SIGFPE))
+  if (compile_options.backtrace)
+    {
+#if defined(SIGSEGV)
+      signal (SIGSEGV, handler);
+#endif
+
+#if defined(SIGBUS)
+      signal (SIGBUS, handler);
+#endif
+
+#if defined(SIGILL)
+      signal (SIGILL, handler);
+#endif
+
+#if defined(SIGFPE)
+      signal (SIGFPE, handler);
+#endif
+    }
+#endif
+
 }