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Is Single step into C++ virtual thunk still broken?


I have waded through the archives but can't find anything newer than 1
year ago discussing this.

I'm using latest cvs gdb and gcc3.1. and specifiying DWARF-2 debug info.

When I single step into a virtual member function of a polymorphic
object in my C++ app, the source display heads off to some random line
in a header file, and another single step takes me back to the next
source line after the virtual function.

Putting a breakpoint in the actual function being called works as
expected.

I quote from a message by Andrew Cagney, 28 Jun 2001:

*****************************
> - Skipping vtable thunks, if necessary


I don't know if this was ever discussed on this list.  As I understand 
it, v3 virtual function is sometimes called via a ``thunk''.  A 
``thunk'' pulls a rabbit out of a hat (finds the correct object to pass 
to the real function) and then passes control to the real function.

At present, if GDB stepped into a thunk it would find no line info, 
treat it like a library and just skip it - oops, step into virtual 
functions via thunks doesn't work.

One proposed solution is to mimic / generalize the shared library 
mechanism so that GDB will single step through it to the real function.

I think this bug is pretty serious since, GDB will, randomly loose 
control over the target.  I certainly think it is more serious than the 
constructor problem.
*****************************

Is this still broke, or am I missing something?

Andrew Walrond
Project Icarus


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