Debug­ging lang/mono – 2^nd round

Today I had again some ener­gy to look at why mono fails to build on FreeBSD-current.

I decid­ed to do a debug-build of mono. This did not work ini­tial­ly, I had to pro­duce some patches. 🙁

Does this mean nobody is doing debug builds of mono on FreeBSD?

I have to say, this expe­ri­ence with lang/mono is com­plete­ly unsatisfying.

Ok, bot­tom line, either the debug build seems to pre­vent a race con­di­tion in most cas­es (I had a lot less lock­ups for each of the two builds I did).

What­ev­er it is, I do not care ATM (if the con­fig­ure stuff is look­ing at the archi­tec­ture of the sys­tem, it may be the case that the i386-portbld-freebsdX does not enable some impor­tant stuff which would be enabled when run with i486-portbld-freebsdX or bet­ter). Here are the patch­es I used in case some­one is inter­est­ed (warn­ing, copy&paste con­vert­ed tabs to spaces, you also have to apply the map.c (a gen­er­at­ed file… maybe a touch of the right file would allow to apply this patch in the nor­mal patch stage) relat­ed stuff when the build fails, else there is some pars­er error in mono):

--- mcs/class/Mono.Posix/Mono.Unix/UnixProcess.cs.orig       2010-01-29 11:34:00.592323482 +0100
+++ mcs/class/Mono.Posix/Mono.Unix/UnixProcess.cs    2010-01-29 11:34:18.540607357 +0100
@@ -57,7 +57,7 @@ namespace Mono.Unix {
 int r = Native.Syscall.waitpid (pid, out status,
 Native.WaitOptions.WNOHANG | Native.WaitOptions.WUNTRACED);
 UnixMarshal.ThrowExceptionForLastErrorIf (r);
-                       return r;
+                       return status;
 }

 public int ExitCode {

--- mono/io-layer/processes.c.orig    2010-01-29 11:36:08.904331535 +0100
+++ mono/io-layer/processes.c 2010-01-29 11:42:21.819159544 +0100
@@ -160,7 +160,7 @@ static gboolean waitfor_pid (gpointer te
 ret = waitpid (process->id, &status, WNOHANG);
 } while (errno == EINTR);

-       if (ret <= 0) {
+       if (ret == 0 || (ret < 0 && errno != ECHILD)) {
 /* Process not ready for wait */
 #ifdef DEBUG
 g_message ("%s: Process %d not ready for waiting for: %s",
@@ -169,6 +169,17 @@ static gboolean waitfor_pid (gpointer te

 return (FALSE);
 }
+
+       if (ret < 0 && errno == ECHILD) {
+#ifdef DEBUG
+               g_message ("%s: Process %d does not exist (anymore)", __func__,
+                          process->id);
+#endif
+               /* Faking the return status. I do not know if it is correct
+                * to assume a successful exit.
+                */
+               status = 0;
+       }

 #ifdef DEBUG
 g_message ("%s: Process %d finished", __func__, ret);

--- mono/metadata/mempool.c.orig      2010-01-29 11:58:16.871052861 +0100
+++ mono/metadata/mempool.c   2010-01-29 12:30:45.143367454 +0100
@@ -212,12 +212,14 @@ mono_backtrace (int size)

         EnterCriticalSection (&mempool_tracing_lock);
         g_print ("Allocating %d bytes\n", size);
+#if defined(HAVE_BACKTRACE_SYMBOLS)
         symbols = backtrace (array, BACKTRACE_DEPTH);
         names = backtrace_symbols (array, symbols);
         for (i = 1; i < symbols; ++i) {
                 g_print ("\t%s\n", names [i]);
         }
         free (names);
+#endif
         LeaveCriticalSection (&mempool_tracing_lock);
 }

--- mono/metadata/metadata.c.orig     2010-01-29 11:59:38.552316989 +0100
+++ mono/metadata/metadata.c  2010-01-29 12:00:43.957337476 +0100
@@ -3673,12 +3673,16 @@ mono_backtrace (int limit)
         void *array[limit];
         char **names;
         int i;
+#if defined(HAVE_BACKTRACE_SYMBOLS)
         backtrace (array, limit);
         names = backtrace_symbols (array, limit);
         for (i =0; i < limit; ++i) {
                 g_print ("\t%s\n", names [i]);
         }
         g_free (names);
+#else
+       g_print ("No backtrace available.\n");
+#endif
 }
 #endif

--- support/map.c.orig        2010-01-29 12:05:22.374653708 +0100
+++ support/map.c 2010-01-29 12:10:29.024412452 +0100
@@ -216,7 +216,7 @@
 #define _cnm_dump(to_t, from) do {} while (0)
 #endif /* def _CNM_DUMP */

-#ifdef DEBUG
+#if defined(DEBUG) && !defined(__FreeBSD__)
 #define _cnm_return_val_if_overflow(to_t,from,val)  G_STMT_START {   \
         int     uns = _cnm_integral_type_is_unsigned (to_t);             \
         gint64  min = (gint64)  _cnm_integral_type_min (to_t);           \