Hiroshi Yamauchi reported on the hotspot-dev mailing list that the fastdebug.make file on Linux does not set a -g or -gstabs debugging option.

The debug flags are set in gcc.make using DEBUG_CFLAGS but fastdebug.make does not use that value. In contrast on Solaris fastdebug.make was updated (way back in 2000) to do:

# Compiler specific DEBUG_CFLAGS are passed in from gcc.make, sparcWorks.make
# They may also specify FASTDEBUG_CFLAGS, but it defaults to DEBUG_CFLAGS.
FASTDEBUG_CFLAGS$(FASTDEBUG_CFLAGS) = $(DEBUG_CFLAGS)

...

# The following lines are copied from debug.make, except that we
# consult FASTDEBUG_CFLAGS instead of DEBUG_CFLAGS.
# Compiler specific DEBUG_CFLAGS are passed in from gcc.make, sparcWorks.make
DEBUG_CFLAGS/DEFAULT= $(FASTDEBUG_CFLAGS)
DEBUG_CFLAGS/BYFILE = $(DEBUG_CFLAGS/$@)$(DEBUG_CFLAGS/DEFAULT$(DEBUG_CFLAGS/$@))
CFLAGS += $(DEBUG_CFLAGS/BYFILE)