Re. How to setup a breakpoint on constructor

Michael Stout
2005-03-09T22:35:08Z

I've hacked my gdb sources to get breakpoints to work on constructors.
Well it seems to work.
see

http://sources.redhat.com/ml/gdb/2004-07/msg00162.html

and

http://sources.redhat.com/ml/gdb/2004-07/msg00163.html

which explains the issue with multiple copies of the constructor

Here is my analysis from someone who is completely unfamiliar with gdb:
There are two essential problems

1) gdb assumes there is a one-to-one mapping between a
file-linenumber-symbol-table and file:linenumber entered by
the user.

a) find_line_common in symtab.c currently only returns one index into
the linnumber-symbol-table where it should
be able to return multiple line numbers.
b) the same is true for find_line_symtab
c) decode_all_digits in linespec.c calls fine_line_symtab needs to
handle the multiple values returned by find_line_symtab

2) gdb assumes a one-to-one mapping between a breakpoint number and a
breakpoint address. I hacked my fix by
using the breakpoint::releated_breakpoint but I don't think this is not
a good fix.

To fix this requires a load of changes. I'm willing to start submitting
patches to get this to work, but I need to have someone
look over my shoulder. The first step would be to modify modify
find_line_common to return multiple indexes.

Here is a simple sample program that illustrates the problem

class gobo
{
public:
gobo();
int i;
};

gobo ::gobo()
{
i = 4;
}

int main(int argc,int **argv)
{
gobo flagger;
}

g++ -g -o foo foo.cpp (g++ 3.3.5 debian)
gdb foo
break foo.cpp:10
run