Re: [rfa/symtab/c++] fix c++ rtti type lookup

[Elena Zannoni <ezannoni at redhat dot com>]

Michael Elizabeth Chastain writes:
 > This patch is a partial fix for PR c++/1465, which is the bug where RTTI
 > lookup gets the "namespace" symbol instead of the class symbol.  It also
 > fixes PR c++/1377, which was another manifestation of the same bug.
 > 
 >   http://sources.redhat.com/gdb/bugs/1465
 >   http://sources.redhat.com/gdb/bugs/1377
 > 
 > These bugs are regressions versus gdb 6.0 so they are high priority.
 > 
 > First, lookup_rtti_type is a new function which takes a name and a block
 > and returns the class type of that name.  It's basically a block of code
 > extracted from gnuv3_rtti_type.  gnuv3_rtti_type calls lookup_rtti_type
 > now.
 > 
 > Then I changed gnuv2_rtti_type to call lookup_rtti_type.  This
 > changes the symbol lookup from VAR_DOMAIN to STRUCT_DOMAIN.
 > 
 > lookup_rtti_type is full of checks and warnings so that it doesn't
 > return crap to its caller.
 > 
 > This fixes the simple cases of the bug.
 > 
 > More work is needed:
 > 
 > . The calls to lookup_rtti_type need a proper "block" parameter.
 >   The old code needed this too; I haven't regressed anything.
 >   I put FIXME notes in for this.
 > 
 > . hpacc_value_rtti_type has the same buggy code.
 >   I can't change the code because I can't test it,
 >     but I can put it a big FIXME into it.
 >   (I wonder if anyone still uses HP aCC with gdb).
 > 

here is a quandary. Should we carry around such code if nobody uses
it. If we cannot test it we might as well explicitly admit it.

 > . Nested types give a warning and don't work.
 >   It would be nice to make them work.
 > 

is there a bug/testcase?

 > . Types with virtual bases appear to work with v3, but give a warning
 >   and don't work with v2.  "don't work" probably means that they fall back
 >   to the static type rather than the dynamic type.
 > 
 > Testing: I tested with gcc v2 and v3, dwarf-2 and stabs+.   
 > Nothing got worse.  gdb.cp/class2.exp has a specific test for this,
 > which now passes.
 > 
 > Some tests in virtfunc.exp that broke after the 2003-09-11 namespace
 > commit started working again.  That was pr gdb/1377.
 > 
 > I think I need approval from a symtab maintainer to add the

If you move the function to cp-support.c and cp-support.h I think you
can avoid touching symtab.h altogether.

 > new utility function "lookup_rtti_type", and then approval
 > from a C++ maintainer to change gnuv2_rtti_type and gnuv3_rtti_type
 > to call lookup_rtti_type.
 > 
 > Okay to commit?
 > 

I think David ok'd it already.

elena