Re: [Texmacs-dev] g++-3.2 segfaults -- linker -- virtual tree destructor

[David Allouche]

On Tue, Nov 05, 2002 at 05:22:21PM +0100, Joris van der Hoeven wrote:
> 
> > What binutils version are you using? I'm now in deep confusion :) Mine is:
> > 
> > $ ld -V
> > GNU ld version 2.13.90.0.10 20021010
> >    Supported emulations:
> >     elf_i386
> >     i386linux
> >     elf_i386_glibc21
> > 
> > I simply want to find a difference. Tests show that guile is probably not 
> > guilty...
> 
> David: can you tell this?
> I don't know whether g++-3.2 uses a different ld.
> I compiled as you said: CXX=g++-3.2 LD=g++-3.2 ./configure and make.

What would you like me to tell???

g++ probably uses the standard linker on the system to build the
executables, and there is no linker present in the g++ distribution.

However, c++ link is much more complex than c link, so g++ does have
some stuff to do with compiled objects before linking them, including but
not restricted ;-) to: run-time type information, exception handling,
template generation, generating implicit operators (perhaps), etc.
(probably more arcane stuff).

By the way, I was also puzzled by the "virtual tree dtor" fix. I
though that there way maybe some broken code which changed tree_rep.op
by mistake, so I did

*** tree.hh     2002/11/06 10:59:05     1.1
--- tree.hh     2002/11/06 10:59:11
***************
*** 114,120 ****
  
  class tree_rep: concrete_struct {
  public:
!   tree_label op;
    inline tree_rep (tree_label op2): op (op2) {}
    friend class tree;
  };
--- 114,120 ----
  
  class tree_rep: concrete_struct {
  public:
!   const tree_label op;
    inline tree_rep (tree_label op2): op (op2) {}
    friend class tree;
  };

That makes sure that tree_rep.op is never modified after object
creation (BTW, I propose this patch for inclusion). If there is some
buggy assignation to tree_rep.op, it will fail to compile.

But, to my dismay, that caused no compilation error.

-- 
David Allouche         | GNU TeXmacs -- Writing is a pleasure
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