From octave-maintainers-request at bevo dot che dot wisc dot edu Thu Jun 28 11:24:50 2001
Subject: gcc-3.0 dynamic loading broken, preliminary patch for feedback
From: Mumit Khan <khan at NanoTech dot Wisc dot EDU>
To: octave-maintainers at bevo dot che dot wisc dot edu
cc: Mumit Khan <khan at NanoTech dot Wisc dot EDU>
Date: Thu, 28 Jun 2001 11:24:47 -0500 (CDT)

Those of who're trying out Octave CVS with gcc-3.0, you'll notice that
dynamic loading is broken, something that I had completely missed. Thanks
to Christoph Spiel for pointing out the obvious.

I have a preliminary patch that does the right thing depending on GNU C++
ABI (v2 aka old, or v3 aka new, and supposedly forever stable), but I need
to write up a autoconf macro for this, and take care of a few other gritty
details such as checking for underscore prefix etc.

I'm including a temporary patch, but please don't depend on this. This is
not meant to go into CVS as is. I'm looking for feedback at this point on
how to do this correctly. I have thought about including the GNU C++
demangling code, but that's a bit more work than I'd like to do at this
point.

You must define a macro GXX_ABI_V3 to enable the new code. To avoid 
rebuilding everything, you can do the following:

  $ cd <octave_build_root>/src
  $ make CXX='c++ -DGXX_ABI_V3' liboctinterp.so

which should build a version that will work. 

** ONLY TESTED ON GNU/Linux **

2001-06-28  Mumit Khan  <khan at nanotech dot wisc dot edu>

	* dynamic-ld.cc (sstream.h): Conditionally include.
	(octave_dynamic_loader::mangle_name): Handle GNU C++ V3 ABI.

Index: dynamic-ld.cc
===================================================================
RCS file: /cvs/octave/src/dynamic-ld.cc,v
retrieving revision 1.64
diff -u -3 -p -r1.64 dynamic-ld.cc
--- dynamic-ld.cc	2000/04/04 06:16:23	1.64
+++ dynamic-ld.cc	2001/06/28 15:38:29
 at @ -38,6 +38,10 @@ Software Foundation, 59 Temple Place - S
 #include "utils.h"
 #include "variables.h"
 
+#if defined(GXX_ABI_V3)
+#include <sstream>
+#endif
+
 // TRUE means we print a warning if reloading a .oct file forces other
 // functions to be cleared.
 static bool Vwarn_reload_forces_clear;
 at @ -311,6 +315,13 @@ octave_dynamic_loader::remove (const std
 std::string
 octave_dynamic_loader::mangle_name (const std::string& name)
 {
+#if defined(GXX_ABI_V3)
+  std::ostringstream mangled_name;
+  unsigned len = name.length ();
+  mangled_name << "_Z" << (len + 2) << "FS";
+  mangled_name << name << "RK12octave_shlib" << std::ends;
+  std::string retval = mangled_name.str ();
+#else /* ! GCXX_ABI_V3 */
 #if defined (CXX_PREPENDS_UNDERSCORE)
   std::string retval ("_FS");
 #else
 at @ -318,6 +329,7 @@ octave_dynamic_loader::mangle_name (cons
 #endif
   retval.append (name);
   retval.append ("__FRC12octave_shlib");
+#endif /* ! GCXX_ABI_V3 */
   return retval;
 }