[M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)

Tony Hosking hosking at cs.purdue.edu
Sat May 15 06:14:54 CEST 2010 

COMPONENT_REF is difficult because of the lack of type info I think.  Please revert to what it used to be.


On 14 May 2010, at 23:10, Jay K wrote:

> 
> http://gcc.gnu.org/ml/gcc/2006-02/msg00577.html
> 
> BIT_FIELD_REF considered harmful
> 
> We should try to use COMPONENT_REF instead.
> 
>  - Jay
> 
> ----------------------------------------
>> From: jay.krell at cornell.edu
>> To: hosking at cs.purdue.edu
>> Date: Sat, 15 May 2010 01:29:01 +0000
>> CC: m3devel at elegosoft.com
>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>> 
>> 
>> Well I'm feeling dumb. That test case surely would print 1 for almost anything.
>> A more accurate one, which shows a problem, is:
>> 
>> #include 
>> 
>> unsigned F1(unsigned a) { return ((a>> 22) & 1); }
>> unsigned F2(unsigned a) { return ((a << 22)>> 31); }
>> 
>> int main()
>> {
>>    unsigned a = 1 << 22;
>>    printf("%x %x\n", F1(a), F2(a));
>>    return 0;
>> }
>> 
>> But I'm still having trouble convincing myself.
>> I guess the second might give you the 10th bit.
>> Er, the 9th.
>> 
>> #include 
>> 
>> unsigned F1(unsigned a) { return ((a>> 22) & 1); }
>> unsigned F2(unsigned a) { return ((a << 22)>> 31); }
>> 
>> int main()
>> {
>>    unsigned a = 1 << 22;
>>    printf("%x %x\n", F1(a), F2(a));
>> 
>>    a = 1 << 9;
>>    printf("%x %x\n", F1(a), F2(a));
>>    return 0;
>> }
>> 
>> 1 0
>> 0 1
>> 
>> - Jay
>> 
>> ----------------------------------------
>>> From: jay.krell at cornell.edu
>>> To: hosking at cs.purdue.edu
>>> Date: Sat, 15 May 2010 01:07:27 +0000
>>> CC: m3devel at elegosoft.com
>>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>> 
>>> 
>>>> < srl %g1, 22, %g1
>>>> < and %g1, 1, %g1
>>>> ---
>>>>> sll %g1, 22, %g1
>>>>> srl %g1, 31, %g1
>>> 
>>> Er.
>>> first: a = (a>> 22) & 1;
>>> second: a = (a << 22)>> 31;
>>> 
>>> are actually darn close, maybe the same.
>>> Let's just be lame and test in C:
>>> 
>>> #include
>>> int main()
>>> {
>>> unsigned a = ~0;
>>> unsigned b = (a>> 22) & 1;
>>> unsigned c = (a << 22)>> 31;
>>> printf("%x %x\n", b, c);
>>> return 0;
>>> }
>>> 
>>> both print 1. So I remain a bit uncertain.
>>> I think undoing just that one change made it go between working and not working, but I also often lose track of what I've cleaned vs. rebuilt.
>>> I might dig more before commiting the undo.
>>> Maybe bit fields of multiple bits are the only ones broken.
>>> 
>>> - Jay
>>> 
>>> 
>>> ----------------------------------------
>>>> From: jay.krell at cornell.edu
>>>> To: hosking at cs.purdue.edu
>>>> Date: Sat, 15 May 2010 00:24:03 +0000
>>>> CC: m3devel at elegosoft.com
>>>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>> 
>>>> 
>>>> Tony I think it is your change to extract_mn.
>>>> Try it with SOLsun for example.
>>>> I see these sorts of differences repeatedly (not to mention works vs. not works, having only undone that change):
>>>> 
>>>> 
>>>> diff cm3-boot-SOLsun-1/Abs.ms cm3-boot-SOLsun-2/Abs.ms
>>>> 77,78c77,78
>>>> < srl %g1, 22, %g1
>>>> < and %g1, 1, %g1
>>>> ---
>>>>> sll %g1, 22, %g1
>>>>> srl %g1, 31, %g1
>>>> 118,119c118,119
>>>> < srl %g1, 22, %g1
>>>> < and %g1, 1, %g1
>>>> ---
>>>>> sll %g1, 22, %g1
>>>>> srl %g1, 31, %g1
>>>> 197,198c197,198
>>>> < srl %g1, 21, %g1
>>>> < and %g1, 1, %g1
>>>> ---
>>>>> sll %g1, 21, %g1
>>>>> srl %g1, 31, %g1
>>>> 236,237c236,237
>>>> < srl %g1, 22, %g1
>>>> < and %g1, 1, %g1
>>>> ---
>>>>> sll %g1, 22, %g1
>>>>> srl %g1, 31, %g1
>>>> 273,274c273,274
>>>> < srl %g1, 22, %g1
>>>> < and %g1, 1, %g1
>>>> 
>>>> 
>>>> This is not optimized.
>>>> They seem equally optimal, but very different.
>>>> Assuming shifts are fast. Could be srl+and is faster than sll+srl.
>>>> srl+and is clearer.
>>>> I don't remember which of these worked.
>>>> 
>>>> 
>>>> < srl %g1, 22, %g1
>>>> 
>>>> < and %g1, 1, %g1
>>>> 
>>>> ---
>>>> 
>>>>> sll %g1, 22, %g1
>>>> 
>>>>> srl %g1, 31, %g1
>>>> 
>>>> 
>>>> 
>>>> I read the first as:
>>>> extract bit 22, plus or minus 1
>>>> vs.
>>>> extract bit 32-22=10, plus or minus 1.
>>>> 
>>>> 
>>>> It would probably be ok to move bits around, but insert would have to match.
>>>> 
>>>> 
>>>> - Jay
>>>> 
>>>> 
>>>> ----------------------------------------
>>>>> From: jay.krell at cornell.edu
>>>>> To: hosking at cs.purdue.edu
>>>>> Date: Fri, 14 May 2010 22:13:58 +0000
>>>>> CC: m3devel at elegosoft.com
>>>>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>>> 
>>>>> 
>>>>> So maybe I386_LINUX is ok..but others not..I need to test more/again/more/again/more/again....
>>>>> 
>>>>> - Jay
>>>>> 
>>>>> ----------------------------------------
>>>>>> From: jay.krell at cornell.edu
>>>>>> To: hosking at cs.purdue.edu
>>>>>> CC: m3devel at elegosoft.com
>>>>>> Subject: RE: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>>>> Date: Fri, 14 May 2010 18:25:59 +0000
>>>>>> 
>>>>>> 
>>>>>> I should disclose that I also rolled back hand.c, though that is mostly or completely implied, due to mod/div/set.
>>>>>> 
>>>>>> 
>>>>>> I have some extra time today, so, plan:
>>>>>> retest head on I386_LINUX (still crossing from Darwin/x86), verify it is broken, since it is all working now
>>>>>> test undo just the bitfield insert/extract change, see if that is the problem
>>>>>> work through the others if not
>>>>>> Possibly verify mod/div test coverage (unless it is the problem, in which
>>>>>> case if I put it back, no need for test coverage, probably nobody will ever
>>>>>> touch it again, which is fine. :) )
>>>>>> I'm pretty sure I tested the set stuff well because I was very nervous but
>>>>>> if others are ruled out I'll undo or test it.
>>>>>> (To clarify, I wasn't even sure by close inspection of the correctness of my NT386
>>>>>> set changes. Only through experimentation/testing could I know that
>>>>>> the definition of bit indices matched up between hand.c and the btc/bts instructions,
>>>>>> it appeared to be a very convenient coincidence.)
>>>>>> 
>>>>>> 
>>>>>> I am surprised that I386_* working and broken.
>>>>>> I would think wordsize and endian is all that matters here.
>>>>>> 
>>>>>> 
>>>>>> I do worry that we are only on gcc 4.3.0 and not even 4.3.3.
>>>>>> But moving up to 4.4.x or 4.5.x is welcome too. :)
>>>>>> 
>>>>>> 
>>>>>> - Jay
>>>>>> 
>>>>>> 
>>>>>> ----------------------------------------
>>>>>>> From: jay.krell at cornell.edu
>>>>>>> To: hosking at cs.purdue.edu
>>>>>>> Date: Fri, 14 May 2010 17:58:29 +0000
>>>>>>> CC: m3devel at elegosoft.com
>>>>>>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>>>>> 
>>>>>>> 
>>>>>>> I don't think anything I've been fiddling with has been dropped by gcc, yet.
>>>>>>> I might have depended on Irix o32 to get up to a working gcc, but no matter.
>>>>>>> I agree if they drop it, we have to.
>>>>>>> Though we could also keep multiple gcc versions if there was really something we wanted,
>>>>>>> but that's not likely.
>>>>>>> A C generating backend also solves this.
>>>>>>> 
>>>>>>> 
>>>>>>> I think I tested my "set" changes on 32bit, 64bit, little endian, big endian, all four combinations.
>>>>>>> But I won't guarantee that now and am very willing to undo them if there is a problem.
>>>>>>> (big endian 64bit would be PPC64_DARWIN, which does have a strong propensity to hang, but also largely works).
>>>>>>> 
>>>>>>> 
>>>>>>> I don't remember about div/mod.
>>>>>>> While it seems "obvious" that the change is correct, it could be that that part of
>>>>>>> gcc is little tested: C and Fortran wouldn't use it. But maybe Ada?
>>>>>>> 
>>>>>>> 
>>>>>>> I'm also not optimizing at all.
>>>>>>> 
>>>>>>> 
>>>>>>> I also agree that rolling forward to any newer gcc is welcome. I just don't know how to do it, at least not
>>>>>>> easily, and I'm also not keen on the huge testing matrix.
>>>>>>> (I think it's roughly what I did for Apple's gcc 4.2, but it was tedious.)
>>>>>>> 
>>>>>>> 
>>>>>>> If it is ICEs we are after though, it is fairly easy to do cross builds and test "everything", automated, given the time to build gcc enough times. :)
>>>>>>> We should really fix the few lingering 32bit/64bit cross bugs, so we can cross build everything.
>>>>>>> 
>>>>>>> 
>>>>>>> Rolling back parse.c, I think every target I've tested (running cm3 bootstrap and making
>>>>>>> sure it gets as far as "can't find cm3.cfg") has worked, except PPC32_OPENBSD.
>>>>>>> This includes PPC_DARWIN, PPC64_DARWIN, I386_LINUX, SPARC64_SOLARIS,
>>>>>>> SPARC64_OPENBSD. (SPARC64_SOLARIS now probably working).
>>>>>>> 
>>>>>>> 
>>>>>>> - Jay
>>>>>>> 
>>>>>>> ----------------------------------------
>>>>>>>> From: hosking at cs.purdue.edu
>>>>>>>> Date: Fri, 14 May 2010 09:59:02 -0400
>>>>>>>> To: jay.krell at cornell.edu
>>>>>>>> CC: m3devel at elegosoft.com
>>>>>>>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>>>>>> 
>>>>>>>> Argh. I worried about that when I made my changes, but all seemed to be well for bootstraps on Darwin/x86.
>>>>>>>> 
>>>>>>>> Also, we need to have regular testing of the compiler at both -O1 and -O2 or -O3 optimisation levels. I know of at least one gcc ICE on one platform (I forget which) that manifests only at -O3 compiling just one module in the entire CM3 distribution. This is fragile stuff... and it may just be a bug in gcc that we are exercising.
>>>>>>>> 
>>>>>>>> It may be that we just need to update the backend to a newer version of gcc. It has been a couple of years, and Jay is pushing the target envelope much further than it ever has been. Problem is that newer gcc may not play nice with older targets. I strongly suggest that we focus effort on modern targets and not older targets, which implies we probably want to roll the gcc-based backend forward to a more current gcc release.
>>>>>>>> 
>>>>>>>> On 14 May 2010, at 06:27, Jay K wrote:
>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> ok, bringing parse.c mostly back to what it is in release, has cleared up a lot of this, I haven't nested it all.
>>>>>>>>> Then I'll have to narrow it down some -- there are two main sets of changes:
>>>>>>>>> - my changes to set operations
>>>>>>>>> - my change to div/mod
>>>>>>>>> - Tony's to bit field operations
>>>>>>>>> 
>>>>>>>>> It is also conceivable that mixing release/head cm3 with head/release cm3cg 1) doesn't work 2) I was doing it.
>>>>>>>>> 
>>>>>>>>> I thought I had tested my changes thoroughly but at this point, I don't know, and don't care much
>>>>>>>>> to keep them if they don't work.
>>>>>>>>> (Well, hopefully the NT386 versions can stay. :) )
>>>>>>>>> 
>>>>>>>>> - Jay
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> ----------------------------------------
>>>>>>>>>> From: jay.krell at cornell.edu
>>>>>>>>>> To: m3devel at elegosoft.com
>>>>>>>>>> Date: Fri, 14 May 2010 09:08:58 +0000
>>>>>>>>>> Subject: Re: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> Hm. Something is wrong on many platforms, in head, at least with my boot archives.
>>>>>>>>>> PPC_DARWIN, SOLsun, I386_LINUX
>>>>>>>>>> I'll figure it out. Hopefully soon.
>>>>>>>>>> 
>>>>>>>>>> - Jay
>>>>>>>>>> 
>>>>>>>>>> ----------------------------------------
>>>>>>>>>>> From: jay.krell at cornell.edu
>>>>>>>>>>> To: m3devel at elegosoft.com
>>>>>>>>>>> Date: Fri, 14 May 2010 06:37:07 +0000
>>>>>>>>>>> Subject: [M3devel] some other ports.. (PPC32_OPENBSD, SPARC64_OPENBSD, SPARC64_SOLARIS)
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> I've tried SPARC64_OPENBSD, SPARC64_SOLARIS, PPC32_OPENBSD recently (this week).
>>>>>>>>>>> 
>>>>>>>>>>> SPARC64_SOLARIS gets far through RTLinker__InitRuntime, but ultimately bus errors in around the first line of RTType__UpdateCell, something in PolyBasis.
>>>>>>>>>>> The data in the assembly looks like. Maybe a runtime memory corruption.
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> PPC32_OPENBSD complains something like in TextCat that a type is missing.
>>>>>>>>>>> I think it used to mostly work since I deleted some install I had there.
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> SPARC64_OPENBSD bus errors just a few instructions into RTLinker__InitRuntime.
>>>>>>>>>>> (gdb) disassem
>>>>>>>>>>> Dump of assembler code for function RTLinker__InitRuntime:
>>>>>>>>>>> 0x00000000004bd01c : save %sp, -224, %sp
>>>>>>>>>>> 0x00000000004bd020 : sethi %hi(0xd18800), %l7
>>>>>>>>>>> 0x00000000004bd024 : add %l7, 0x1fc, %l7 ! 0xd189fc
>>>>>>>>>>> 0x00000000004bd028 : call 0x4bd010 <_m3_fault+60>
>>>>>>>>>>> 0x00000000004bd02c : nop
>>>>>>>>>>> 0x00000000004bd030 : stx %i0, [ %fp + 0x87f ]
>>>>>>>>>>> 0x00000000004bd034 : stx %i1, [ %fp + 0x887 ]
>>>>>>>>>>> 0x00000000004bd038 : stx %i2, [ %fp + 0x88f ]
>>>>>>>>>>> 0x00000000004bd03c : stx %i3, [ %fp + 0x897 ]
>>>>>>>>>>> 0x00000000004bd040 : sethi %hi(0x942c00), %g1
>>>>>>>>>>> 0x00000000004bd044 : or %g1, 0x290, %g1 ! 0x942e90
>>>>>>>>>>> 0x00000000004bd048 : ldx [ %l7 + %g1 ], %g1 << here
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> This seems like it'll be tough going. :(
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> I think I'll try with PIC turned off.
>>>>>>>>>>> 
>>>>>>>>>>> - Jay
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>> 
>>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>> 
>>>> 
>>> 
>> 
>

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