constructor breakpoints

constructor breakpoints

[Doug Evans]

Having recently tripped over this (not being able to set breakpoints
on constructors), and having read as much of the sordid history of
this as I can find, I wonder what the current thinking is on how to
fix this.  Has there been any progress?

bash$ ./gdb -nx testsuite/gdb.cp/overload
(gdb) b foo::foo
[0] cancel
[1] all
?HERE
?HERE
?HERE
>

The ?HERE's are because symbol lookup finds the class, not the
constructor.  Being able to specifically ask for the constructor seems
like a reasonable way to go.  This could be done by encoding the
request in the name (looking up c::c), or specifying the class of
object to lookup (e.g. LOC_BLOCK), or rearranging the symbol table
such that one can lookup the class, and then from that lookup (or
iterate) over members that match certain parameters.  [I'm just
throwing out a range of possibilities.]

Re: constructor breakpoints

[Daniel Jacobowitz]

On Thu, Mar 27, 2008 at 05:04:57PM -0700, Doug Evans wrote:
> Having recently tripped over this (not being able to set breakpoints
> on constructors), and having read as much of the sordid history of
> this as I can find, I wonder what the current thinking is on how to
> fix this.  Has there been any progress?

Not that I know of.  Hey, at least we fixed the _other_ breakpoints in
constructors bug.

> The ?HERE's are because symbol lookup finds the class, not the
> constructor.  Being able to specifically ask for the constructor seems
> like a reasonable way to go.  This could be done by encoding the
> request in the name (looking up c::c), or specifying the class of
> object to lookup (e.g. LOC_BLOCK), or rearranging the symbol table
> such that one can lookup the class, and then from that lookup (or
> iterate) over members that match certain parameters.  [I'm just
> throwing out a range of possibilities.]

I like that last one - I always have - but I'm a little worried about
how much work it would be in practice; neither stabs nor dwarf symbol
info is really laid out quite right for it.

-- 
Daniel Jacobowitz
CodeSourcery