[bfd] Redirecting function calls in object files

["Ames Andreas" <Andreas dot Ames at comergo dot com>]

Hi all,

please note, that I'm almost a complete newbie when it comes to libbfd
and linker techniques in general.

I'm writing a test facility for a bunch of C++ modules.  To this end I
want to 'fix' function calls within an object file to point to some
stub functions, i.e. I want to test a given class (given as an object
file) by replacing calls to instances of other classes with calls to
stubs provided by my test facility.  I'm currently only interested in
pei- and elf-targets.  Requiring that the object contains symbols is
no problem, because I have the sources for the classes under test.

As I understand so far, please correct me, this shouldn't be a problem
for functions in sections, for which bfd_is_und_section is true,
because I can just define them in another compilation unit and the
linker will pick them up.  I can't figure out how this could work for
functions defined in the same compilation unit as the class under
test (think templates, for example).  So here are the questions:

1) If they aren't inlined, can libbfd help me to replace the call(s)
   to the original function defined in the object file under test to a
   stub function defined in another object file, provided by my test
   facility?  If so, how?

2) Can I use libbfd to determine if the interesting functions are
   inlined within the object under test (e.g. to issue an error
   message and require a recompilation with no inlining)?  Is it
   certain that all calls to the same function within a single
   compilation unit are either inlined or not (this is more of a
   compiler question, I guess)?

Any pointers to docs or sample code (if it doesn't mean I have to
understand the whole ld code at once :-) and general explanations are
appreciated.


TIA,

aa

-- 
Andreas Ames | Programmer | Comergo GmbH |
Voice:  +49 69 7505 3213 | ames AT avaya . com