[PATCH v2 0/9] share minimal symbols across objfiles

[Tom Tromey <tromey@redhat.com>]

This patch series changes minimal symbols to be independent of the
program space, and then to be stored in the per-BFD object.  That way,
they can be shared by all objfiles referring to a given BFD.  This
saves memory, and, in the case of ELF, the time spent re-reading the
symbols.

In order to make a minimal symbol independent of the program space,
the correct objfile offset must be applied when the symbol's address
is computed.  This series achieves that by introducing a two-argument
form of SYMBOL_VALUE_ADDRESS (but done in a way to ensure that all
errors will be caught at compile time); more fully completing the
switchover to the use of bound minimal symbols; and finally by
changing the definition of the new macro to apply the offsets.

This is an update of a patch series I sent earlier:

    https://sourceware.org/ml/gdb-patches/2011-12/msg00470.html

This version differs from the above in that:

* There are no FIXMEs left
* I updated all the minimal symbol readers
* The use of bound minimal symbols (and the earlier removal of
  msymbol_objfile) solves any potential problem with dlmopen
* The earlier series to fix how sections are represented in symbols
  removes the need for the old "index" patches

I built and regtested this on x86-64 Fedora 18 (with the defaults and
with -gstabs+), PPC Linux (gcc110 in the compile farm), and AIX
(gcc111 in the compile farm).  I also built it on Fedora 18 using the
mingw cross compiler.


Please note that, while I made my best effort to fix everything
properly, there's really quite a bit here I can't test.  In
particular, I have no way to test most of the changes I made to the
various symbol readers, in patch #8.

If you could, I'd ask that you please test or at least carefully
review the relevant bits there.  I've pushed this branch to archer.git
tromey/split-objfile/msymbol-location-independence to make this
simpler.

thanks,
Tom