Use of STABS debug format

[Coleen Phillimore]

I would love for stabs to go away for linux 32 bit.   I think there was 
a size issue once with that platform and was filling up our disk.  I 
think I changed this recently and noticed that the issue is gone.   I'll 
file a bug (if there isn't one already) and remove stabs for linux.   
Stabs still work better for solaris.

This still doesn't fix my problem that even the latest version of gdb 
still can't show or stop in inlined functions on 32 bit (works on 64 
bit).   Is there a bug for this?   It would be nice if this was fixed.

Thanks,
Coleen

On 7/30/2012 7:42 PM, Andrew Hughes wrote:
> Hi all,
>
> It seems that following:
>
> 7071904: 4/4 HotSpot: Full Debug Symbols
> http://hg.openjdk.java.net/jdk8/jdk8/hotspot/rev/da0999c4b733
>
> a number of architectures on Linux (including x86) have started building with the
> STABS debug format rather than DWARF.
>
> This is presumably due to the addition of this block:
>
> +ifneq ($(OBJCOPY),)
> + FASTDEBUG_CFLAGS/ia64 = -g
> + FASTDEBUG_CFLAGS/amd64 = -g
> + FASTDEBUG_CFLAGS/arm = -g
> + FASTDEBUG_CFLAGS/ppc = -g
> + FASTDEBUG_CFLAGS += $(DEBUG_CFLAGS/$(BUILDARCH))
> + ifeq ($(FASTDEBUG_CFLAGS/$(BUILDARCH)),)
> + FASTDEBUG_CFLAGS += -gstabs
> + endif
> +
> + OPT_CFLAGS/ia64 = -g
> + OPT_CFLAGS/amd64 = -g
> + OPT_CFLAGS/arm = -g
> + OPT_CFLAGS/ppc = -g
> + OPT_CFLAGS += $(OPT_CFLAGS/$(BUILDARCH))
> + ifeq ($(OPT_CFLAGS/$(BUILDARCH)),)
> + OPT_CFLAGS += -gstabs
> + endif
> +endif
> +
>
> Prior to this, I don't believe product builds had debug information by default.  You'd
> have to set DEBUG_BINARIES (something we do).
>
> Is there a reason to use STABS any more?  For our part, it's causing bugs such as:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=841057
>
> This statement:
>
> # Use the stabs format for debugging information (this is the default
> # on gcc-2.91). It's good enough, has all the information about line
> # numbers and local variables, and libjvm_g.so is only about 16M.
> # Change this back to "-g" if you want the most expressive format.
>
> seems dated (Fedora, for example, is on gcc 4.7) and the size argument
> seems redundant, given debug information is now stripped and stored in
> separate compressed files by default.
>
> Is there any reason to retain the use of STABS on x86 and SPARC, the only supported
> architectures not opted out above as far as I can tell?
>
> Note that our concern is the Linux makefile and we're more than happy to leave STABS
> in place on Solaris and *BSD, if necessary, as we don't build there :-)