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Re: m68k bootstrapping broken
Richard Zidlicky wrote:
By the way, do you also agree that -fomit-frame-pointer is always
a win on m68k? AFAIK, gdb handles it correctly and all
-fomit-frame-pointer bugs should have been fixed.
I have gdb-6.0 here and dont see how it does work, although
I would be really glad if baktrace would work. Compiling stuff
with "-gdwarf-2 -g3" - am I missing something?
I usually use -ggdb. GDB 6.0 still has some problems with the
ColdFire BDM target, so I'm primarly using 5.3. I vaguely recall
seeing correct backtraces in the uClinux kernel, which is compiled
by default with -fomit-frame-pointer. But perhaps
My proposal is to switch m68k to imply -fomit-frame-pointer with
-O. Of course, I think we're too late for 3.4, so it will have
to be postponed even if we all agree.
it would be -O2 if at all.
fp elimination is a trivial optimization that adds very little
compile-time impact and doesn't affect code layout, so it's
enabled at -O1:
`-O' also turns on `-fomit-frame-pointer' on machines where doing
so does not interfere with debugging.
For m68k-linux it has the additional side effect of enforcing
a stricter interpretaion of our slightly unusual a0/d0/fp0 abi
so it wont be so good to have this as default.
I don't understand why the fp should interact with
the way you store return values in registers...
Anyway, if it's problematic for m68k-linux we could
enable it on selected OS targets instead of doing
it globally.
--
// Bernardo Innocenti - Develer S.r.l., R&D dept.
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