Hello everybody,
On Friday 07 March 2008 Philipp Marek wrote:
> Here you are.
>
>
> code_overlap.pl - disassembles a binary, and outputs a list
> (address, name, instruction, bytes) to STDOUT.
>
> bytes_saved.pl - takes such a list, and tries to estimate
> the amount of bytes that could be sav
On Friday 07 March 2008 Ian Lance Taylor wrote:
> "Philipp Marek" <[EMAIL PROTECTED]> writes:
> >> Shouldn't this be done in the linker instead?
> >
> > Well, can the linker change the instruction sequences? Ie. put a JMP
> > instead of other code?
>
> Sure. The linker can do whatever it likes.
"Philipp Marek" <[EMAIL PROTECTED]> writes:
>> Shouldn't this be done in the linker instead?
> Well, can the linker change the instruction sequences? Ie. put a JMP
> instead of other code?
Sure. The linker can do whatever it likes. The usual problem is that
by the time the linker sees the cod
BTW - It gets much better:
$ ls -la /usr/lib/libgcj.so.90.0.0
-rw-r--r-- 1 root root 32844984 3. Feb 16:03 /usr/lib/libgcj.so.90.0.0
$ ./run /usr/lib/libgcj.so.90.0.0
Approx. 470045 bytes saved.
That's 1.4% :-)
If my script isn't buggy, that is
--
Versioning your /etc, /home or
Hello Jakub!
>> When wouldn't that possible? My script currently splits on an
>> instruction-level -- although I would see no problem that some branch
>> jumps into a "half" opcode of another branch, if the byte sequence
>> matches.
>
> Consider:
> :
>0: b8 a4 00 00 00
On Fri, Mar 07, 2008 at 01:05:03PM +0100, Philipp Marek wrote:
> When wouldn't that possible? My script currently splits on an
> instruction-level -- although I would see no problem that some branch
> jumps into a "half" opcode of another branch, if the byte sequence
> matches.
Consider:
On Fri, Mar 7, 2008 at 12:46 PM, Jakub Jelinek <[EMAIL PROTECTED]> wrote:
> On Fri, Mar 07, 2008 at 11:10:53AM +0100, Richard Guenther wrote:
> > On Fri, Mar 7, 2008 at 11:02 AM, Philipp Marek <[EMAIL PROTECTED]> wrote:
>
> > > I wrote some perl scripts to test this. I took a "alldefconfig" i686
Hello Jakub!
> You need to be very careful with it, as if there are any jumps
> into the middle of the to be abstracted tail sequences, you can't
> abstract them or would need to adjust also the jumps into them (if
> possible, which not always is).
When wouldn't that possible? My script currently
Hello Dave!
> One achitectural problem here is that GCC doesn't emit bytes. It emits
> ASCII text, in the form of assembly instructions, and it's
> not always easy to predict how they'll look by the time they've been
> through the assembler and then had relocs applied by the
> linker. (Indeed, to
On Fri, Mar 07, 2008 at 11:10:53AM +0100, Richard Guenther wrote:
> On Fri, Mar 7, 2008 at 11:02 AM, Philipp Marek <[EMAIL PROTECTED]> wrote:
> > I wrote some perl scripts to test this. I took a "alldefconfig" i686
> > kernel, let objdump disassemble it, and on "iret", "ret", "ljmp" or "jmp"
> >
Philipp Marek wrote:
> I'd like to (manually) define some byte blocks, eg. as functions with
> an identifier. Then, if GCC would emit exactly these bytes, it
> puts a JMP identifier there instead.
One achitectural problem here is that GCC doesn't emit bytes. It emits ASCII
text, in the form
Hello Michael!
> Can I test your script in my embedded system?
> Can you send to me?
Here you are.
code_overlap.pl - disassembles a binary, and outputs a list
(address, name, instruction, bytes) to STDOUT.
bytes_saved.pl - takes such a list, and tries to estimate
the amount of bytes that c
Hello Richard!
[ I took linux-tiny out - it's moderated, and I don't want to spam them. ]
> Sounds like what -frtl-abstract-sequences is trying to do.
Yes, thank you. I didn't know that; that should be close.
*But*: I think it doesn't work.
$ size vmlinux-as vmlinux-Os
textdata b
Hi,
Philipp Marek wrote:
Hello everybody,
I have a feature request.
and my scripts emit space savings of about 30kB. Now that's not
that much, but for embedded systems it means another userspace
binary more.
[ If anyone's interested, I can post my scripts here ... they're not
that large.
On Fri, Mar 7, 2008 at 11:02 AM, Philipp Marek <[EMAIL PROTECTED]> wrote:
> Hello everybody,
>
> I have a feature request.
>
>
> I'd like to (manually) define some byte blocks, eg. as functions with an
> identifier. Then, if GCC would emit exactly these bytes, it puts a JMP
> identifier there
Hello everybody,
I have a feature request.
I'd like to (manually) define some byte blocks, eg. as functions with an
identifier. Then, if GCC would emit exactly these bytes, it puts a JMP
identifier there instead.
This would help by sharing many identical (text/code) byte sequences, to
make a s
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