From: Nick Owens <mischief@9.offblast.org>
To: 9fans@9fans.net
Subject: [9fans] 8l -e
Date: Tue, 27 May 2014 13:10:16 -0700 [thread overview]
Message-ID: <20140527201016.GP3763@iota.offblast.org> (raw)
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i was trying to use 8l's '-e' flag today, when i found some
interesting problems.
first, -e doesn't do what it says unless you pass -p, which goes
unmentioned in the manual page. (luckily i read the source).
second, and more importantly, the calls to _tracein/_traceout are
skipped, as in the following disassembly, but i can't determine why. is
there some tool (besides noping with acid) meant to be used to 'turn on'
the tracing calls?
third, when you use -e with -p, prof.$pid files are generated as with
-p, but the prof files are empty. this seems unintentional.
this example is using rc.
; 8l -p -e -o 8.out code.8 exec.8 getflags.8 glob.8 here.8 io.8 lex.8
pcmd.8 pfnc.8 simple.8 subr.8 trap.8 tree.8 var.8 havefork.8 plan9.8
y.tab.8
; acid 8.out
8.out:386 plan 9 executable
/sys/lib/acid/port
/sys/lib/acid/386
acid: asm(setvar)
setvar 0x0000adbb JMP setvar+0x7(SB)
setvar+0x2 0x0000adbd CALL _tracein(SB)
setvar+0x7 0x0000adc2 SUBL $0x10,SP
setvar+0xa 0x0000adc5 MOVL name+0x0(FP),CX
setvar+0xe 0x0000adc9 MOVL CX,0x0(SP)
setvar+0x11 0x0000adcc CALL vlook(SB)
setvar+0x16 0x0000add1 MOVL AX,v+0xc(SP)
setvar+0x1a 0x0000add5 MOVL 0x4(AX),AX
setvar+0x1d 0x0000add8 MOVL AX,0x0(SP)
setvar+0x20 0x0000addb CALL freewords(SB)
setvar+0x25 0x0000ade0 MOVL v+0xc(SP),DX
setvar+0x29 0x0000ade4 MOVL val+0x4(FP),CX
setvar+0x2d 0x0000ade8 MOVL CX,0x4(DX)
setvar+0x30 0x0000adeb MOVL $0x1,0x8(DX)
setvar+0x37 0x0000adf2 ADDL $0x10,SP
setvar+0x3a 0x0000adf5 RET
setvar+0x3b 0x0000adf6 CALL _traceout(SB)
setvar+0x40 0x0000adfb RET
Xasync 0x0000adfc JMP Xasync+0x7(SB)
acid:
you can see there is a JMP over _tracein and a RET before _traceout.
what gives?
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next reply other threads:[~2014-05-27 20:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-27 20:10 Nick Owens [this message]
2014-05-27 20:16 ` erik quanstrom
2014-05-27 21:30 ` Nick Owens
2014-05-27 21:33 ` erik quanstrom
2015-07-08 2:43 ` michaelian ennis
2015-07-08 2:44 ` michaelian ennis
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