b31 multiple build failures on x86 Linux

[David Holmes - Sun Microsystems]

Kelly O'Hair said the following on 07/23/08 05:17:
> Jeffrey Baker wrote:
>> Third problem: fastdebug_build target doesn't seem to propagate the -g
>> flag.  All of hotspot was built with -fPIC -fno-rtti -fno-exceptions
>> -fcheck-new -m32 -march=i586 -pipe -O3 -fno-strict-aliasing
>> -Wpointer-arith -Wconversion -Wsign-compare, i.e. without -g.  I
>> thought the point of the fastdebug target was to build with -g -O.
> 
> Yes, it should have. That's a new one on me.
> I see that the debug build seems to use -gstabs, but it looks
> like linux/makefiles/fastdebug.make forgot to add -gstabs to CFLAGS.
> It's possible that they removed it with 64bit mode because of the
> size problems with Dwarf2 debug format, and accidently removed it for
> 32bit too. :^(   Sounds like a bug to me.

The debug flags are handled in gcc.make:

hypert /scratch/mirrors/ws-mirrors/java7/open/hotspot/make > tail -15 
linux/makefiles/gcc.make
#------------------------------------------------------------------------
# Debug flags

# 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.
# (warning: that could easily inflate libjvm_g.so to 150M!)
# Note: The Itanium gcc compiler crashes when using -gstabs.
DEBUG_CFLAGS/ia64  = -g
DEBUG_CFLAGS/amd64 = -g
DEBUG_CFLAGS += $(DEBUG_CFLAGS/$(BUILDARCH))
ifeq ($(DEBUG_CFLAGS/$(BUILDARCH)),)
DEBUG_CFLAGS += -gstabs
endif

See also bug 6485088

Cheers,
David Holmes