Re: [RFA] stabs: remember types that cross reference another type

[Elena Zannoni <ezannoni at redhat dot com>]

Joel Brobecker writes:
 > [Rhaaaa, resending, with the patch this time. Thanks Daniel!]
 > 
 > Hello,
 > 
 > We encountered the following problem when using GNAT to compile
 > the following pasted at the end of this message. Sorry the program
 > is in Ada instead of C, but I couldn't reproduce it with C.
 > 
 > The problem is when the user tries to print the type of My_Str.
 > GDB should return a string, but instead we got:
 > 
 >         Attempt to take contents of a non-pointer value
 > 
 > After investigating, I found that the stabs generated by the compiler
 > contained the following entries:
 > 
 >         .stabs "s5:(0,97)=xsstring___XUP:",128,0,5,-476
 >         .stabs "R6b:(0,97)",128,0,12,-484
 > 
 > (R6b is a variable that GDB ends up using in place of My_Str for reasons
 > that are related to the encoding used by GNAT).
 > 
 > So when GDB reads the type information for R6b, it finds that it is
 > of type number (0,97), which should mean the same type as s5.
 > Unfortunately, GDB forgot to save a reference to the type associated
 > to type (0,97) in the type_vector when processing the type of variable
 > named "s5". So later on, when GDB tries to compute the type of "R6b",
 > it doesn't find type (0,97) and therefore assumes it will be defined
 > later, and hence creates a empty type object which it hopes will be 
 > filled in later.
 > 
 > As a consequence, when the ada mode tries to print the type of R6b,
 > it trips over the unexpected symbol type code, and bails out with
 > the error message above.
 > 
 > The attached patch fixes this particular case.
 > 
 > 2003-10-31  J. Brobecker  <brobecker@gnat.com>
 > 
 >         * stabsread.c (read_type): Save a reference to types that are defined
 >         as cross references to other types.
 > 
 > Tested on x86-linux, no regression.
 > 
 > Ok to apply?
 > 


Yes, but the comment before that loop you are changing needs some
revamping. Reading it, it really looks like it is a useless/obsoleted
thing we are doing here, while now it's not the case anymore. I mean,
it is useful.

elena