Re: How to build gnat on top of egcs-1.1.2, please?

[Gary Gourley <not@here.org>]

>David C. Hoos, Sr." wrote:
> You make no mention of which Linux distribution (e.g., RedHat,
> Slackware, etc.) or which hardware platform (e.g., Standard PC,
> Power PC, etc.).

Basically, my i586 box is based on Redhat 5.0 but i am
running kernel 2.2.5. Actually, you can get this information
from  the field X-Mailer of the header of this message.

> 
> The best place for answers to GNAT on Linux is the Ada for
> Linux Team.  their web site is at
> http://www.cl.cam.ac.uk/~mgk25/linux-ada/
> 

Thanks. I have visited the site before. They have a patch
for egcs-1.1.1 only ... and seems that it doesn't work with
egcs-1.1.2

> Robert Dewar told me on the phone recently that an egcs built GNAT >would be very likely to be less reliable than a gcc 2.8 built GNAT. 

Oh, really? Are there any GNU testsuites for GNAT? Just like
the dejagnu testsuites for C, C++ and fortran? So we can
test it objectively.

> Unfortunately, too many users seem to be more interested in
> "getting the very latest thing" than in getting a really robust and
> well-tested product.

haha, you are quite right but I guess I am not. I still use
Redhat 5.0 based system and upgrade to kernel-2.2.5 myself
only very recently.

> 
> We should not be so naive and get excited about egcs, just because 
> it is newer in some way. Some of the comments here sound as if 
> there is a really significant performance or any other advantage to 
> be gained by building gnat on top of egcs. I would like to see hard 
> performance numbers first before I get enthusiastic about these 
> things. I have not yet seen any performance improvement by egcs 
> that would justify for me the risk of switching to the much less 
> well tested egcs environment. Gcc 2.8 is a pretty damn good code 
> generator already and egcs does not seem to contain any 
> Ada-specific code generator improvements.
> 

> Finally -- Why build it yourself?  Why not just use one of the 
> several binary GNAT distributions for Linux?

I wanna build it myself with egcs because I have applied the
Pentium processor optimization patch from Pentium Compiler
Group (www.goof.com/pcg) to egcs-1.1.2. The resulting binary
run faster on my 200MMx. For example, bzip2 built with
pgcc-1.1.2 (egcs + the Pentium patch) do compression much
much faster than egcs not to mention gcc-2.8. Here is the
result of a small test on the time egcs-generated bzip2 and
patched-egcs-generated bzip2 spent in compressing the linux
kernel-2.2.3 on a Intel 200MMX. 

__________________________________________________________________
TEST: time tar cvfI linux-2.2.3 kernel (54978KB) 
on a 200 MMX, 64MB SDRAM, IBM UDMA33 Harddisk 
__________________________________________________________________

bzip2, compile time option: -O6 -mpentium on egcs-1.1.2(no
patch)

Compression time:

244.66user 5.73system 4:34.04elapsed 91%CPU
(0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (15640major+1670minor)pagefaults 0swaps
--------------------------------------------------------------
bzip2, compile time option -06 -mpentium
--fno-strength-reduce on egcs-1.1.2 with the patch frpm
Pentium Compiler Group

Compression time:

227.25user 5.06system 4:22.11elapsed 88%CPU
(0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (15648major+1670minor)pagefaults 0swaps

--------------------------------------------------------------

> 
> I hope this helps
> 
> David C. Hoos, Sr.

Yes, thanks again. I guess I will upgrade my gcc-2.7.2.3 to
gcc-2.8.1 and build gnat with 2.8.1. Btw, are there any gnat 
patch for gdb-4.18?

Thanks

-gary