Referencing C++ functions with non-demangled names.

Referencing C++ functions with non-demangled names.

[Daniel Manfis]

Hello.

If i want to set breakpoint on a C++ function, how could i do it 
using it's usual and not mangled name? I tried to turn on 
"set print demangle" and "set print asm-demangle", but it doesn't 
help: whenever i try to put breakpoint on a C++ function (in my own 
code) with it's non-demangled name (like: 'break main.cc:f'), i get a 
message: 

'function "f" not defined'

and i have to either use mangled name or line number.


Daniel.

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Re: Referencing C++ functions with non-demangled names.

[Daniel Berlin]

"Daniel Manfis" <dany_100@yahoo.com> writes:

> Hello.
> 
> If i want to set breakpoint on a C++ function, how could i do it 
> using it's usual and not mangled name? I tried to turn on 
> "set print demangle" and "set print asm-demangle", but it doesn't 
> help: whenever i try to put breakpoint on a C++ function (in my own 
> code) with it's non-demangled name (like: 'break main.cc:f'), i get a 
> message: 
> 
> 'function "f" not defined'
> 
> and i have to either use mangled name or line number.

Errr, I need a test case, it works fine here.
I also need to know what compiler version, etc, you are using.

The workaround is to quote it, or remove the filename: from the front
(or both).
C++ functions with the same name must be the same function, by the
one definition rule, so prefixing it like that is pointless.

Regardless, even if the workaround works, some more information would
be helpful, since i can't reproduce this problem with any compilers i
have around here.

--Dan

-- 
"I saw a subliminal advertising executive, but only for a second.
"-Steven Wright

Re: Referencing C++ functions with non-demangled names.

[Daniel Manfis]

> Errr, I need a test case, it works fine here.
> I also need to know what compiler version, etc, you are using.

linux : Mandrake 7.2 (kernel 2.2.17-21mdk)
gcc   : 3.0, snapshot 20010423
gdb   : 5.0 (RPM from/for Mandrake 7.2)

test case:
//////////////////////////////////////////////////////////////////////
// File name : a.cc

void f() {}

int main()
{
	f() ;
}
//////////////////////////////////////////////////////////////////////
I compile with one of the following options, all of them give the 
same results:

g++ -ggdb3    a.cc
g++ -g3        a.cc
g++ -gstabs+3 a.cc



> The workaround is to quote it, or remove the filename: from the 
> front (or both). C++ functions with the same name must be the same 
> function, by the one definition rule, so prefixing it like that is 
> pointless.

Here is what i tried to do to set a breakpoint on functoin 'f', all 
of the methods failing:

break a.cc:f
break 'a.cc:f'
break f
break 'f'

(i couldn't use double-quotes: when i try to do that (break "f"), 
gdb crashes with segmentation fault (as it is, by the way, when you 
type "break .")).

But i could set a breakpoint on 'f' function with the following 
expression:

break _Z1fv 
 
The only function breakpoint i could set using function's non-mangled 
name, is the 'main' function breakpoint (using "break main" 
expression. Probably the reason i succeeded to set breakpoint on 
'main' with it's non-mangled name, is because it's name is not 
mangled (at least when i step through the program, gdb never prints 
'main''s name in a mangled form, as it does with all the other C++ 
functions).

Also, i couldn't set breakpoints on functions in a namespaces unless 
i use it's mangled name, a notation like "break 'ns::f'" won't do 
(instead, provided there is function 'f' in a namespace 'ns', i have  
to use "break _ZN2ns1fEv") Generally, namespaces are not recognized 
at all. For example, if i type "break ns::" and press <ESC-?>, 
instead of displaying functions from that namespace, all functions in 
the scope are displayed (as it happens when you type "break" and 
press <ESC-?>).


I thought that maybe there is a problem with gdb's RPM package i am 
using, but it is impossible for me to check - i barely have a space 
to ungzip a source package, let along build it.


Daniel.


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Re: Referencing C++ functions with non-demangled names.

[Daniel Berlin]

"Daniel Manfis" <dany_100@yahoo.com> writes:

> > Errr, I need a test case, it works fine here.
> > I also need to know what compiler version, etc, you are using.
> 
> linux : Mandrake 7.2 (kernel 2.2.17-21mdk)
> gcc   : 3.0, snapshot 20010423
> gdb   : 5.0 (RPM from/for Mandrake 7.2)

You can't use gdb 5.0 with gcc 3.0 snapshots and expect it to work. GDB 5 was
released before gcc 3.0 even branched, and doesn't have support for
the newer demangling style.

Use a newer gdb (like a snapshot), and it should work fine.

> to use "break _ZN2ns1fEv") Generally, namespaces are not recognized 
> at all. For example, if i type "break ns::" and press <ESC-?>, 
> instead of displaying functions from that namespace, all functions in 
> the scope are displayed (as it happens when you type "break" and 
> press <ESC-?>).
Once again, you have to quote it to get completion to work in 5.0.
It's a bug that's particularly heinous to fix in a clean way.


-- 
"I have a friend named Dennis.  Both of his parents were midgets,
but he isn't a midget.  He's a midget-dwarf.  He's two inches
tall.  He's the one who poses for trophies.
"-Steven Wright