Re: [rfa/doc] correct info about best C++ compilers/debug formats

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Feb 03, 2003 at 10:27:30AM -0800, David Carlton wrote:
> As noted in PR symtab/874, the information in the manual about the
> best debug formats for C++ is not only incorrect but actively
> harmful.  Here's an attempt at a patch.  So:
> 
> * Eli: Is the TeXinfo okay?  What about the choice of cindex entries?
>   When I actually looked at the index, I found that it generated three
>   consecutive entries "C++ and ..." that all pointed at the same
>   place; I'm tempted to get rid of the C++ and GCC entry, since that's
>   really a special case of C++ and compilers.
> 
> * Daniel (and Michael): Is the content okay?  I decided to take a
>   conservative approach, not promising support for compilers/debug
>   formats that we don't intend to work on.

I think so.

> * Daniel, Michael: Once this goes in, should we get rid of the DWARF 1
>   xfails in gdb.c++ and simply not run the C++ testsuite under DWARF
>   1?

I'm inclined to agree.  Michael?

> 
> I'd like to apply this to 5.3 as well as mainline, on the slim chance
> that 5.3.1 might happen, because the information in the doc now really
> is bad.
> 
> David Carlton
> carlton@math.stanford.edu
> 
> 2003-02-03  David Carlton  <carlton@math.stanford.edu>
> 
> 	* gdb.texinfo (C plus plus expressions): Correct info about
> 	compiler/debug formats for C++ debugging.  PR symtab/874.
> 
> Index: gdb.texinfo
> ===================================================================
> RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
> retrieving revision 1.145
> diff -u -p -r1.145 gdb.texinfo
> --- gdb.texinfo	1 Feb 2003 20:51:06 -0000	1.145
> +++ gdb.texinfo	3 Feb 2003 18:08:27 -0000
> @@ -8062,28 +8062,22 @@ and @samp{@{&"hi", &"there", &"fred"@}} 
>  @cindex expressions in C@t{++}
>  @value{GDBN} expression handling can interpret most C@t{++} expressions.
>  
> -@cindex C@t{++} support, not in @sc{coff}
> -@cindex @sc{coff} versus C@t{++}
> -@cindex C@t{++} and object formats
> -@cindex object formats and C@t{++}
> -@cindex a.out and C@t{++}
> -@cindex @sc{ecoff} and C@t{++}
> -@cindex @sc{xcoff} and C@t{++}
> +@cindex C@t{++} and debug formats
> +@cindex debug formats and C@t{++}
>  @cindex @sc{elf}/stabs and C@t{++}
>  @cindex @sc{elf}/@sc{dwarf} and C@t{++}
> -@c FIXME!! GDB may eventually be able to debug C++ using DWARF; check
> -@c periodically whether this has happened...
> +@cindex C@t{++} compilers
> +@cindex C@t{++} and @value{NGCC}
> +@cindex @value{NGCC} and C@t{++}
>  @quotation
>  @emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the
> -proper compiler.  Typically, C@t{++} debugging depends on the use of
> -additional debugging information in the symbol table, and thus requires
> -special support.  In particular, if your compiler generates a.out, MIPS
> -@sc{ecoff}, RS/6000 @sc{xcoff}, or @sc{elf} with stabs extensions to the
> -symbol table, these facilities are all available.  (With @sc{gnu} CC,
> -you can use the @samp{-gstabs} option to request stabs debugging
> -extensions explicitly.)  Where the object code format is standard
> -@sc{coff} or @sc{dwarf} in @sc{elf}, on the other hand, most of the C@t{++}
> -support in @value{GDBN} does @emph{not} work.
> +proper compiler and the proper debug format.  Currently, @value{GDBN}
> +works best when debugging C@t{++} code that is compiled with
> +@value{NGCC} 2.95.3 or with @value{NGCC} 3.1 or newer, using the options
> +@option{-gdwarf-2} or @option{-gstabs+}.  DWARF 2 is preferred over
> +stabs; newer versions of @value{NGCC} use DWARF 2 as the default
> +whenever possible.  Other compilers and/or debug formats are likely to
> +work badly or not at all when using @value{GDBN} to debugg C@t{++} code.
>  @end quotation
>  
>  @enumerate
> 
> 

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer