Hi,

In support of our work on Janos (an active networks platform), we have
implemented a system for combined profiling of C and JIT'ed Java code
in Kaffe.  This makes it possible to produce timing and call graph
data covering both languages in a format that can be understood by GNU
gprof.  The implementation works much like regular C profiling, it
gets timing information by regularly sampling the current value of the
PC and adds a call to an `mcount' like function to the beginning of
JIT'ed methods.  Then, at exit, the profiling data is written out, as
well as an assembler file containing symbol information for the JIT'ed
code.  Finally, the JIT'ed code symbol file and a symbol file created
from the Kaffe executable are assembled and fed into gprof to create
the output.

In addition, we have implemented basic functionality to support cross
language debugging in gdb and for feeding back JIT information into
subsequent runs of Kaffe.  Cross language debugging simply takes the
line debugging information from the Java class and outputs it to an
assembler file using the same code the profiler used.  Then, while
executing in gdb you can assemble the current output file and add the
symbols to gdb's current state, allowing it to report the current
file/line information for JIT'ed Java code.  The feedback system
allows Kaffe to save certain bits of state to a file so that it can
optimize future runs based on past information.  Currently, this is
only used for preloading libraries and pre-JIT'ing methods.  However,
it should be flexible enough to hold more data that can be used to do
other tricks.

More information, and a patch (187K), and a complete Kaffe source
distribution (both based on early May, 2000 CVS snapshots) can be
found on the Janos Kaffe page:
	http://www.cs.utah.edu/flux/janos/kaffe.html

More information about these additions can be found in the
FAQ.xprofiler, FAQ.xdebugging, and FAQ.feedback files (which are also
on the web page).

Before asking that this stuff get comitted to the main tree, we're
looking for some feedback on it.  So please send any comments to this
list, the Janos list (janos-discuss@flux.cs.utah.edu) or to myself
(tullmann@cs.utah.edu) and Tim Stack (stack@cs.utah.edu).

Tim Stack, our most recent Kaffe Wizard at Utah, actually implemented
all of this.  I'm just announcing it.

For those interested in what was actually changed, here is a ChangeLog
entry:

	* FAQ/FAQ.xprofiler, FAQ/FAQ.xdebugging, FAQ/FAQ.feedback,
	kaffe/scripts/kaffexprof.in, kaffe/scripts/nm2as.awk,
	kaffe/libraries/clib/management/XProfiler.c,
	kaffe/libraries/javalib/kaffe/management/XProfiler.java,
	configure.in, kaffe/kaffe/main.c, config/i386/jit3-i386.def,
	config/i386/freebsd2/md.h, config/i386/linux/md.h,
	include/Makefile.am, include/Makefile.in, kaffe/Makefile.am,
	kaffe/Makefile.in, kaffe/kaffe/Makefile.am,
	kaffe/kaffe/Makefile.in,
	kaffe/kaffevm/systems/unix-jthreads/Makefile.am,
	kaffe/kaffevm/Makefile.am, kaffe/kaffevm/Makefile.in,
	kaffe/kaffevm/jit3/Makefile.am,
	kaffe/kaffevm/jit3/Makefile.in, kaffe/kaffevm/baseClasses.c,
	kaffe/kaffevm/classMethod.c, kaffe/kaffevm/external.c,
	kaffe/kaffevm/external.h, kaffe/kaffevm/jni.c,
	kaffe/kaffevm/methodCache.c, kaffe/kaffevm/methodCache.h,
	kaffe/kaffevm/stringSupport.h, kaffe/kaffevm/utf8const.c,
	kaffe/kaffevm/jit3/machine.c, kaffe/xprof,
	kaffe/xprof/Makefile.am, kaffe/xprof/Makefile.in,
	kaffe/xprof/callGraph.h, kaffe/xprof/callGraph.c,
	kaffe/xprof/debugFile.h, kaffe/xprof/debugFile.c,
	kaffe/xprof/feedback.h, kaffe/xprof/feedback.c,
	kaffe/xprof/fileSections.h, kaffe/xprof/fileSections.c,
	kaffe/xprof/gmonFile.h, kaffe/xprof/gmonFile.c,
	kaffe/xprof/gmon_out.h, kaffe/xprof/mangle.h,
	kaffe/xprof/mangle.c, kaffe/xprof/memorySamples.h,
	kaffe/xprof/memorySamples.c, kaffe/xprof/sectionFile.h,
	kaffe/xprof/sectionFile.c, kaffe/xprof/xprofiler.h,
	kaffe/xprof/xprofiler.c: Added/modified to support xprofiling,
	xdebugging, and feedback.