[Changeset]: Re: Problem with dbstep

[David Bateman]

John W. Eaton wrote:
> On  9-Jul-2008, David Bateman wrote:
>
> | Looking at the backtrace I assume that this is with a recent HG build..
> | Note that there were changes commited to the repository yesterday that
> | relate to these aspects. However, just testing this example it crashes
> | before and after applying these changes.
> | 
> | The fix is clearly that the pt-bp.h (MAYBE_DO_BREAKPOINT) macro has to
> | recognize that ta function is returning and not break or decrement its
> | counters. However, I'm not sure how that should be implemented. JWE what
> | is the means to check whether a function is returning in this macro?
>
> Yes, we need to decide what should happen when we are at the end of a
> function and there is no next line to step to.  As a temporary fix, it
> might be OK to just not allow stepping, but I think it would be
> better to step to the next line in the calling function (if any) or
> back to the top level prompt.  But I don't really understand the
> debugging code very well, and I don't know what the proper fix is.
>
> Also, I noticed that for the example function (which takes an argument)
>
>   dbstop test
>   test
>   dbstep
>
> also crashes Octave when it tries to print the error message and I
> don't know what the proper fix is for that either.
>   
Forget it. The fix is easy.. As far as I see we shouldn't be testing for
a breakpoint for the lvalue or rvalue of a function definition. Just
removing the MAYBE_DO_BREAKPOINT from pt-id.cc fixes the issue. Patch
attached.

D.

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# HG changeset patch
# User David Bateman <address@hidden>
# Date 1215619791 -7200
# Node ID 42d92afd9fa2be9716c2e424f189d067b0b47f68
# Parent  c7fa906e597358bd6a2f11bafc457b317b6b6f76
Fix seg-fault for dbstep at end of function

diff --git a/src/ChangeLog b/src/ChangeLog
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@ 2008-07-08  John W. Eaton  <address@hidden
+2008-07-09  David Bateman  <address@hidden>
+
+       * pt-id.cc (octave_value_list tree_identifier::rvalue (int), 
+       octave_lvalue tree_identifier::lvalue (void)): Remove 
+       MAYBE_DO_BREAKPOINT.
+
 2008-07-08  John W. Eaton  <address@hidden>
 
        * graphics.h.in (axes::properties::keypos): Declare as
diff --git a/src/pt-id.cc b/src/pt-id.cc
--- a/src/pt-id.cc
+++ b/src/pt-id.cc
@@ -57,8 +57,6 @@ tree_identifier::rvalue (int nargout)
 {
   octave_value_list retval;
 
-  MAYBE_DO_BREAKPOINT;
-
   if (error_state)
     return retval;
 
@@ -117,8 +115,6 @@ octave_lvalue
 octave_lvalue
 tree_identifier::lvalue (void)
 {
-  MAYBE_DO_BREAKPOINT;
-
   return octave_lvalue (&(xsym().varref ()));
 }