A bad EH bug

[hjl at lucon dot org (H.J. Lu)]

> > 
> > > On Tue, Oct 13, 1998 at 02:48:36PM -0700, Joe Buck wrote:
> > 
> > >> Please send a complete test case (a complete program) to
> > >> egcs-bugs@cygnus.com, so that the experts will be able to run it through
> > >> and figure out what goes wrong.
> > 
> > > This demonstrates the problem quite effectively. However, I'm afraid
> > > it's rather big. I had a (quick) crack at isolating the problem with
> > > little success.
> > 

# gcc bad.cc -g
# a.out
Foo::Foo
Foo::~Foo
zsh: 12158 segmentation fault  ./a.out
# gdb a.out
(gdb) r
(gdb) r
Starting program: /home/hjl/bugs/g++/opt.3/a.out 
Foo::Foo
Foo::~Foo

Program received signal SIGSEGV, Segmentation fault.
0x804a2b1 in __cp_pop_exception (p=0x4002fbaa)
    at /home/work/misc/gnu/src/egcs-1.1/gcc/cp/exception.cc:211
211       --p->handlers;
(gdb) bt
#0  0x804a2b1 in __cp_pop_exception (p=0x4002fbaa)
    at /home/work/misc/gnu/src/egcs-1.1/gcc/cp/exception.cc:211
#1  0x804947e in Base::dispatch (this=0xbffffc17, x=0) at bad.cc:80
#2  0x80494e9 in main () at bad.cc:101


BTW, it failed on Solaris/Sparc. But it works on HP-UX 10.20. It seems
it affects all platforms with DWARF2 based EH. FYI, egcs 1.0.3 is ok.
It must be a new bug. I'd like to see it be fixed in egcs 1.1.1.

Could someone please clean it up and put it into the g++ testsuite?

Thanks.


-- 
H.J. Lu (hjl@gnu.org)
---
#include <stdio.h>

class Base
{
public:
  int dispatch (int);
};

class Derived : public Base
{
};

class Foo
{
public:
  Foo ();
  ~Foo ();
  int getValue (int);
};

template<class T>
class OBObjVar
{
  T* ptr;
public:
  OBObjVar (T *p) : ptr (p) {}
  ~OBObjVar() { delete ptr; }
  T* operator->() const { return ptr; }
};

Foo * getFoo ();
Foo::Foo ()
{
  printf ("Foo::Foo\n");
}

Foo::~Foo ()
{
  printf ("Foo::~Foo\n");
}

int
Foo::getValue (int x)
{
  return x;
}

Foo*
getFoo ()
{
  return new Foo;
}

int
Base::dispatch (int x)
{
  int y = 1;

  while (y)
    {
      OBObjVar<Foo> f = getFoo ();

      try 
	{
	  y = f->getValue (x);
	}
      catch (const char *s)
	{
	  printf ("Base::dispatch: %s\n", s);
	  if (x == 0)
	    {
	      y = 0;
	      continue;
	    }

	  throw;
	}
      catch (int)
	{
	  continue;
	}

      if (y == 0)
	{
	  f->getValue (y);
	  throw "Throw an exception!";
	}

      break;
    }
  return y;
}

int
main ()
{
  Derived x;

  try
    {
      x.dispatch (0);
    }
  catch (const char *s)
    {
      printf ("Caught: %s\n", s);
    }
}