Re: debugging in-build-tree glibc

[Roland McGrath <roland at redhat dot com>]

> Currently I just run /path/to/build-$(PLATFORM)/elf/ld-linux.so.2
> directly under GDB and replicate the --library-path, executable
> path, et al. arguments that the build itself uses.

Btw, testrun.sh in the build directory exists to make those options easy to
find.

> This allows me to debug but since we're debugging ld.so directly
> the loading of new files does not get caught by gdb so no symbol
> information is available for anything outside of ld.so itself.
> If I really need the symbol information I look at the output of
> /proc/${PID-of-ld-linux.so.2}/maps and lookup the symbol names
> manually.  To say the least, this is cumbersome...

I often wind up doing the same thing, but I use gdb's add-symbol-file
command.  It's a little cumbersome in that you have to figure out the vma
of .text in the .so file (with objdump or readelf or whatnot), add the
mapping address to yield the runtime address of its .text, and give the
resulting number in the second argument to add-symbol-file.  But that's
less cumbersome than converting addresses by hand.