Re: [RFC] fix probe-related internal error on AIX

[Sergio Durigan Junior <sergiodj at redhat dot com>]

On Thursday, March 06 2014, Tom Tromey wrote:

> While testing on AIX, I happened to notice an internal error coming
> from parse_probes.  This happens because there are no probes defined
> on this platform.  This patch fixes the problem by changing an assert
> into an ordinary error, and then changing the relevant caller to cope.
>
> This fixes a few tests on AIX; also regtested on x86-64 Fedora 18.

Ouch, thanks for testing on other platforms!

By reading the patch (and the original code), I found it a little bit
obscure, so I took the liberty to try to improve it.  Here's the patch.
Could you please take a look and see if it works on AIX (and also if you
like the approach)?

Thanks,

2014-03-06  Tom Tromey  <tromey@redhat.com>
	    Sergio Durigan Junior  <sergiodj@redhat.com>

	* probe.c (parse_probes): Turn assert into an ordinary error.
	* break-catch-throw.c (re_set_exception_catchpoint): Ignore
	exceptions when parsing probes.  Rearrange the code for clarity.

diff --git a/gdb/break-catch-throw.c b/gdb/break-catch-throw.c
index 7283490..9831d96 100644
--- a/gdb/break-catch-throw.c
+++ b/gdb/break-catch-throw.c
@@ -207,29 +207,32 @@ re_set_exception_catchpoint (struct breakpoint *self)
   volatile struct gdb_exception e;
   struct cleanup *cleanup;
   enum exception_event_kind kind = classify_exception_breakpoint (self);
-  int pass;
 
-  for (pass = 0; sals.sals == NULL && pass < 2; ++pass)
+  /* We first try to use the probe interface.  */
+  TRY_CATCH (e, RETURN_MASK_ERROR)
     {
-      TRY_CATCH (e, RETURN_MASK_ERROR)
+      char *spec = ASTRDUP (exception_functions[kind].probe);
+
+      sals = parse_probes (&spec, NULL);
+    }
+
+  if (e.reason < 0)
+    {
+      volatile struct gdb_exception ex;
+
+      /* Using the probe interface failed.  Let's fallback to the normal
+	 catchpoint mode.  */
+      TRY_CATCH (ex, RETURN_MASK_ERROR)
 	{
-	  char *spec;
-
-	  if (pass == 0)
-	    {
-	      spec = ASTRDUP (exception_functions[kind].probe);
-	      sals = parse_probes (&spec, NULL);
-	    }
-	  else
-	    {
-	      spec = ASTRDUP (exception_functions[kind].function);
-	      self->ops->decode_linespec (self, &spec, &sals);
-	    }
+	  char *spec = ASTRDUP (exception_functions[kind].function);
+
+	  self->ops->decode_linespec (self, &spec, &sals);
 	}
+
       /* NOT_FOUND_ERROR just means the breakpoint will be pending, so
 	 let it through.  */
-      if (e.reason < 0 && e.error != NOT_FOUND_ERROR)
-	throw_exception (e);
+      if (ex.reason < 0 && ex.error != NOT_FOUND_ERROR)
+	throw_exception (ex);
     }
 
   cleanup = make_cleanup (xfree, sals.sals);
diff --git a/gdb/probe.c b/gdb/probe.c
index 623f65c..838d9f9 100644
--- a/gdb/probe.c
+++ b/gdb/probe.c
@@ -59,7 +59,8 @@ parse_probes (char **argptr, struct linespec_result *canonical)
 
   cs = *argptr;
   probe_ops = probe_linespec_to_ops (&cs);
-  gdb_assert (probe_ops != NULL);
+  if (probe_ops == NULL)
+    error (_("'%s' is not a probe linespec"), arg_start);
 
   arg = (char *) cs;
   arg = skip_spaces (arg);

-- 
Sergio