[M3devel] FW: bad code on PPC_LINUX?

Thu Jan 10 14:11:33 CET 2008

Removing -fPIC seems to fix this, though the code still stinks and the frame is still huge (700+ bytes).
Even with -O, even without -gstabs (adding/removing -gstabs shouldn't matter but I tried anyway)

 - Jay
________________________________
> From: jayk123 at hotmail.com
> To: m3devel at elegosoft.com
> Date: Thu, 10 Jan 2008 09:28:31 +0000
> Subject: [M3devel] FW: bad code on PPC_LINUX?
> 
> My emails keep getting truncated for some reason.. :(
> 
> 
> ________________________________
>> From: jayk123 at hotmail.com
>> To: m3devel at elegosoft.com
>> Subject: bad code on PPC_LINUX?
>> Date: Thu, 10 Jan 2008 07:11:11 +0000
>>
>>
>> Something is screwy I think.
>> My gdb skills are um not good.
>>
>> On PPC_LINUX.
>>
>> /dev2/cm3/m3-sys/cm3/src/Utils.m3
>>
>> PROCEDURE WriteFile (file: TEXT; proc: Emitter; append := FALSE) =
>> VAR wr: Wr.T;
>> BEGIN
>> IF (append)
>> THEN wr := AppendWriter (file, fatal := TRUE);
>> ELSE wr := OpenWriter (file, fatal := TRUE);
>> END;
>> TRY (* line 78 *)
>> TRY
>> proc (wr);
>> EXCEPT
>> | Wr.Failure (ec) =>
>> Msg.FatalError (ec, "write failed on ", file);
>> | Thread.Alerted =>
>> Msg.FatalError (NIL, "interrupted while writing ", file);
>> END;
>> FINALLY
>> CloseWriter (wr, file);
>> END;
>> END WriteFile;
>>
>> I get a SEGV on line 78.
>>
>> I'm willing to believe, sadly, that some of these huge offsets
>> are the price of TRY and saving the register context on anything
>> other than x86 (for registers that aren't even used by the function?),
>> however it crashes just after the call and notice there the huge 32k offset.
>>
>> And really? A 720 byte frame for any function with a TRY on PowerPC?
>> Really?
>> I guess I should look at what PPC_DARWIN does.
>>
>> If someone can give me a quick run down on PowerPC ABI, thanks.
>> I'll search the web. Or maybe check my Mac docs.
>> register 0 is 0 or general purpose?
>> Stack is register ?
>> I know that return address is in the link register.
>> bl is branch and link -- call -- jump and save pc in link register.
>>
>> The code is:
>> (gdb) disassemble
>> Dump of assembler code for function Utils__WriteFile:
>> 0x10024fbc : stwu r1,-720(r1)
>> 0x10024fc0 : mflr r0
>> 0x10024fc4 : mfcr r12
>> 0x10024fc8 : stfd f14,576(r1)
>> 0x10024fcc : stfd f15,584(r1)
>> 0x10024fd0 : stfd f16,592(r1)
>> 0x10024fd4 : stfd f17,600(r1)
>> 0x10024fd8 : stfd f18,608(r1)
>> 0x10024fdc : stfd f19,616(r1)
>> 0x10024fe0 : stfd f20,624(r1)
>> 0x10024fe4 : stfd f21,632(r1)
>> 0x10024fe8 : stfd f22,640(r1)
>> 0x10024fec : stfd f23,648(r1)
>> 0x10024ff0 : stfd f24,656(r1)
>> 0x10024ff4 : stfd f25,664(r1)
>> 0x10024ff8 : stfd f26,672(r1)
>> 0x10024ffc : stfd f27,680(r1)
>> 0x10025000 : stfd f28,688(r1)
>> 0x10025004 : stfd f29,696(r1)
>> 0x10025008 : stfd f30,704(r1)
>> 0x1002500c : stfd f31,712(r1)
>> 0x10025010 : stw r14,504(r1)
>> 0x10025014 : stw r15,508(r1)
>> 0x10025018 : stw r16,512(r1)
>> 0x1002501c : stw r17,516(r1)
>> 0x10025020 : stw r18,520(r1)
>> 0x10025024 : stw r19,524(r1)
>> 0x10025028 : stw r20,528(r1)
>> 0x1002502c : stw r21,532(r1)
>> ---Type to continue, or q to quit---
>> 0x10025030 : stw r22,536(r1)
>> 0x10025034 : stw r23,540(r1)
>> 0x10025038 : stw r24,544(r1)
>> 0x1002503c : stw r25,548(r1)
>> 0x10025040 : stw r26,552(r1)
>> 0x10025044 : stw r27,556(r1)
>> 0x10025048 : stw r28,560(r1)
>> 0x1002504c : stw r29,564(r1)
>> 0x10025050 : stw r30,568(r1)
>> 0x10025054 : stw r31,572(r1)
>> 0x10025058 : stw r0,724(r1)
>> 0x1002505c : stw r12,500(r1)
>> 0x10025060 : mr r31,r1
>> 0x10025064 : bl 0x10025068
>> 0x10025068 : mflr r30
>> 0x1002506c : lwz r0,-176(r30)
>> 0x10025070 : add r30,r0,r30
>> 0x10025074 : stw r3,8(r31)
>> 0x10025078 : stw r4,12(r31)
>> 0x1002507c : mr r0,r5
>> 0x10025080 : stb r0,16(r31)
>> 0x10025084 : li r0,0
>> 0x10025088 : stw r0,20(r31)
>> 0x1002508c : lbz r0,16(r31)
>> 0x10025090 : clrlwi r0,r0,24
>> 0x10025094 : cmpwi r0,0
>> 0x10025098 : beq- 0x100250b8
>> 0x1002509c : lwz r3,8(r31)
>> 0x100250a0 : li r4,1
>> 0x100250a4 : bl 0x100248a4
>> ---Type to continue, or q to quit---
>> 0x100250a8 : stw r3,476(r31)
>> 0x100250ac : lwz r9,476(r31)
>> 0x100250b0 : stw r9,20(r31)
>> 0x100250b4 : b 0x100250d0
>> 0x100250b8 : lwz r3,8(r31)
>> 0x100250bc : li r4,1
>> 0x100250c0 : bl 0x10024658
>> 0x100250c4 : stw r3,476(r31)
>> 0x100250c8 : lwz r9,476(r31)
>> 0x100250cc : stw r9,20(r31)
>>
>> ** here I believe **
>>
>> 0x100250d0 : lwz r0,-32760(r30)
>> 0x100250d4 : stw r0,32(r31)
>> 0x100250d8 : addi r0,r31,8
>> 0x100250dc : stw r0,36(r31)
>> 0x100250e0 : li r0,3
>> 0x100250e4 : stw r0,28(r31)
>> 0x100250e8 : lwz r9,-32764(r30)
>> 0x100250ec : lwz r0,0(r9)
>> 0x100250f0 : stw r0,24(r31)
>> 0x100250f4 : lwz r9,-32764(r30)
>> 0x100250f8 : addi r0,r31,24
>> 0x100250fc : stw r0,0(r9)
>> 0x10025100 : lwz r9,-32768(r30)
>> 0x10025104 : addi r0,r9,76
>> 0x10025108 : stw r0,64(r31)
>> 0x1002510c : li r0,0
>> 0x10025110 : stw r0,60(r31)
>> 0x10025114 : lwz r9,-32764(r30)
>> 0x10025118 : lwz r0,0(r9)
>> 0x1002511c : stw r0,56(r31)
>> ---Type to continue, or q to quit---
>> 0x10025120 : lwz r9,-32764(r30)
>> 0x10025124 : addi r0,r31,56
>> 0x10025128 : stw r0,0(r9)
>> 0x1002512c : addi r9,r31,56
>> 0x10025130 : addi r0,r9,48
>> 0x10025134 : mr r3,r0
>> 0x10025138 : bl 0x101bbf28
>> 0x1002513c : mr r0,r3
>> 0x10025140 : cmpwi r0,0
>> 0x10025144 : bne- 0x100251ac
>> 0x10025148 : lwz r9,12(r31)
>> 0x1002514c : stw r9,476(r31)
>> 0x10025150 : lwz r9,476(r31)
>> 0x10025154 : cmpwi r9,0
>> 0x10025158 : beq- 0x10025188
>> 0x1002515c : lwz r9,476(r31)
>> 0x10025160 : lwz r0,0(r9)
>> 0x10025164 : li r9,-1
>> 0x10025168 : cmpw r0,r9
>> 0x1002516c : bne- 0x10025188
>> 0x10025170 : lwz r9,476(r31)
>> 0x10025174 : lwz r9,8(r9)
>> 0x10025178 : stw r9,480(r31)
>> 0x1002517c : lwz r9,476(r31)
>> 0x10025180 : lwz r9,4(r9)
>> 0x10025184 : stw r9,476(r31)
>> 0x10025188 : lwz r11,480(r31)
>> 0x1002518c : lwz r3,20(r31)
>> 0x10025190 : lwz r0,476(r31)
>> 0x10025194 : mtlr r0
>> ---Type to continue, or q to quit---
>> 0x10025198 : blrl
>> 0x1002519c : lwz r9,-32764(r30)
>> 0x100251a0 : lwz r0,56(r31)
>> 0x100251a4 : stw r0,0(r9)
>> 0x100251a8 : b 0x10025210
>> 0x100251ac : lwz r9,68(r31)
>> 0x100251b0 : lwz r9,0(r9)
>> 0x100251b4 : lis r0,-15535
>> 0x100251b8 : ori r0,r0,42454
>> 0x100251bc : cmpw r9,r0
>> 0x100251c0 : bne- 0x100251f0
>> 0x100251c4 : lwz r0,72(r31)
>> 0x100251c8 : stw r0,472(r31)
>> 0x100251cc : lwz r9,-32768(r30)
>> 0x100251d0 : addi r0,r9,180
>> 0x100251d4 : lwz r3,472(r31)
>> 0x100251d8 : mr r4,r0
>> 0x100251dc : lwz r5,8(r31)
>> 0x100251e0 : li r6,0
>> 0x100251e4 : li r7,0
>> 0x100251e8 : bl 0x10023b4c
>> 0x100251ec : b 0x10025210
>> 0x100251f0 : lwz r9,-32768(r30)
>> 0x100251f4 : addi r0,r9,212
>> 0x100251f8 : li r3,0
>> 0x100251fc : mr r4,r0
>> 0x10025200 : lwz r5,8(r31)
>> 0x10025204 : li r6,0
>> 0x10025208 : li r7,0
>> 0x1002520c : bl 0x10023b4c
>> ---Type to continue, or q to quit---
>> 0x10025210 : lwz r9,-32764(r30)
>> 0x10025214 : lwz r0,24(r31)
>> 0x10025218 : stw r0,0(r9)
>> 0x1002521c : addi r11,r31,8
>> 0x10025220 : bl 0x10024f74
>> 0x10025224 : lwz r11,0(r1)
>> 0x10025228 : lwz r0,4(r11)
>> 0x1002522c : lwz r12,-220(r11)
>> 0x10025230 : mtlr r0
>> 0x10025234 : lwz r14,-216(r11)
>> 0x10025238 : lwz r15,-212(r11)
>> 0x1002523c : lwz r16,-208(r11)
>> 0x10025240 : lwz r17,-204(r11)
>> 0x10025244 : lwz r18,-200(r11)
>> 0x10025248 : lwz r19,-196(r11)
>> 0x1002524c : lwz r20,-192(r11)
>> 0x10025250 : lwz r21,-188(r11)
>> 0x10025254 : lwz r22,-184(r11)
>> 0x10025258 : lwz r23,-180(r11)
>> 0x1002525c : lwz r24,-176(r11)
>> 0x10025260 : lwz r25,-172(r11)
>> 0x10025264 : lwz r26,-168(r11)
>> 0x10025268 : lwz r27,-164(r11)
>> 0x1002526c : lwz r28,-160(r11)
>> 0x10025270 : lwz r29,-156(r11)
>> 0x10025274 : lwz r30,-152(r11)
>> 0x10025278 : lwz r31,-148(r11)
>> 0x1002527c : lfd f14,-144(r11)
>> 0x10025280 : lfd f15,-136(r11)
>> 0x10025284 : lfd f16,-128(r11)
>> ---Type to continue, or q to quit---
>> 0x10025288 : lfd f17,-120(r11)
>> 0x1002528c : lfd f18,-112(r11)
>> 0x10025290 : lfd f19,-104(r11)
>> 0x10025294 : lfd f20,-96(r11)
>> 0x10025298 : lfd f21,-88(r11)
>> 0x1002529c : lfd f22,-80(r11)
>> 0x100252a0 : lfd f23,-72(r11)
>> 0x100252a4 : lfd f24,-64(r11)
>> 0x100252a8 : lfd f25,-56(r11)
>> 0x100252ac : lfd f26,-48(r11)
>> 0x100252b0 : lfd f27,-40(r11)
>> 0x100252b4 : lfd f28,-32(r11)
>> 0x100252b8 : lfd f29,-24(r11)
>> 0x100252bc : lfd f30,-16(r11)
>> 0x100252c0 : lfd f31,-8(r11)
>> 0x100252c4 : mtcrf 56,r12
>> 0x100252c8 : mr r1,r11
>> 0x100252cc : blr
>> 0x100252d0 : .long 0x24ebb0
>> End of assembler dump.
>>
>>
>> (gdb) bt
>> #0 Utils__WriteFile (M3_Bd56fi_file=0x10277ba0, M3_DmuccK_proc=0x7fb22210,
>> M3_AicXUJ_append=0 '\0') at Utils.m3:78
>> #1 0x10020a10 in Makefile__Build (M3_Bd56fi_src_dir=0x102720ec)
>> at Makefile.m3:101
>> #2 0x100292d4 in Main__DoIt () at Main.m3:71
>> #3 0x10029834 in Main_M3 (M3_AcxOUs_mode=1) at Main.m3:193
>> #4 0x10188f9c in RTLinker__RunMainBody (M3_DUuepq_m=0x10279b28)
>> at RTLinker.m3:387
>> #5 0x101880bc in RTLinker__AddUnitI (M3_DUuepq_m=0x10279b28) at RTLinker.m3:100
>> #6 0x10188198 in RTLinker__AddUnit (M3_DUuepw_b=0x100297f8) at RTLinker.m3:110
>> #7 0x100002ec in main (argc=1, argv=0x7fb22834, envp=0x7fb2283c) at _m3main.mc:4
>>
>> I haven't yet figured out how to get gdb to show me the details of the SEGV, like what address was referenced.
>>
>> I swear I think this was working better recently.
>>
>> Oh, I did change something. I will try to change it back.
>> I added -fPIC.
>> Dynamic linking was not working and I thought that might fix it.
>> I'll definitely try without it now.
>>
>> Also, relevant aside -- what, if any, distributions/versions of Linux are people using on PowerPC?
>> Specifically on PowerPC (to limit the religious explosion)
>> I'm currently using Yellow Dog, I think 4.1, but only for Modula-3 purposes, not for anything else.
>>
>> ps: I'd like a SMALL forum of SMART programmers, to discuss GENERAL programming topics.
>> This is it perhaps?
>>
>> - Jay
>> _________________________________________________________________
>> Watch “Cause Effect,” a show about real people making a real difference.
>> http://im.live.com/Messenger/IM/MTV/?source=text_watchcause
> 
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