Question

[Volker Simonis]

Hi Guys,

time to go back to the original topic:

here comes a 'disassembler_i486.cpp' that uses a vanilla
'libopcodes.so' how it comes with every binutils distribution. It can
be used as a simple replacement for the current
'disassembler_i486.cpp'. The only requirements during compile time is
'dis-asm.h' which is also provided by the binutils package. Usually
this should be availabel on Linux and should be no problem on Windows
as well if you use Cygwin anyway (I tried only on Linux).

After compiling the HotSpot with the new version of
'disassembler_i486.cpp' you should now be able to use the various
print options like for example -XX:+PrintCompilation
-XX:+PrintAssembly, -XX:+PrintInterpreter and get a nice assembly
output of wht's going on under the hood.

@chenjie: this should also work on MIPS as binutils support MIPS.
Could you check? Maybe it can be helpfull for your porting project.

Implementation details
--------------------------
I specially kept the diff to the original file small, so you can
easily see what the crucial changes are. If this should get into the
official release, we can of course get rid of a few things like for
example the class 'i486_env' and 'Disassembler::decode_instruction'
that arn't needed anymore.

For other architectures, all that has to be done, is adapt the
following lines in 'init_disassemble_info()':

  // Platform dependent stuff (i486)
  di.bytes_per_line = 0;
  di.endian = (bfd_endian) 1;
  di.mach = bfd_mach_i386_i8086;
  di.disassembler_options = (char *) "i386,suffix";

and choose the right name for the disassembler function in
'Disassembler::load_library()':

hpi::dll_lookup(_library, "print_insn_i386");

The specific names for other architectures can be found in 'dis-asm.h'.

Pitfalls
--------
On my Suse Linux 10 I had a broken 'libopcodes.so' ("nm
/usr/lib/libopcodes.so" returned no symbols. But building a new
version of binutils is quite tricky too, because you HAVE to give
./configure the "--enable-64-bit-bfd" option (even on 32bit Linux),
otherwise the resulting 'libopcodes.so' wont work! Heres my configure
line for building binutils 2.17:

./configure --enable-shared --enable-64-bit-bfd

Afterwards, just copy opcodes/.libs/libopcodes-2.17.so to /usr/lib and
let /usr/lib/libopcodes.so link to it. That's it.

Regards,
Volker

On 8/8/07, Peter B. Kessler <Peter.Kessler at sun.com> wrote:
> Christian Thalinger wrote:
>
> > On Wed, 2007-08-08 at 12:45 -0700, Peter B. Kessler wrote:
> >
> > Hi Peter!
> >
> >> Could we move this thread from hotspot-compiler-dev at openjdk.dev.java.net
> >> to hotspot-compiler-dev at openjdk.java.net?  The first list just forwards
> >> to the second list, but since you all are subscribed to the second list
> >> but not the first list, I have to approve all your postings to the first
> >> list.  That means my lack of attention is just slowing you all down.
> >> I'm in the way to serve as a spam filter.  (Part of garbage collection? :-)
> >
> > Hehe :-)
> >
> >> I assume most of you are just hitting "Reply-All" and so aren't even
> >> aware of the difference between openjdk.dev.java.net and openjdk.java.net.
> >> But you might also want to check your address books to see that new posts
> >> to hotspot-compiler-dev will go to openjdk.java.net.
> >
> > OK.  This list?
> >
> > - twisti
>
>
> Yes.  Thanks.  Now, what was the original topic? :-)
>
>                         ... peter
>
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