clang/ARM regression

[Tim Kientzle]

On Apr 27, 2013, at 7:16 PM, Oleksandr Tymoshenko wrote:

> Hi,
> 
> There seems to be some kind of regression in recently imported clang on ARM.
> Beaglebone kernel built using clang  with WITNESS enabled panics
> on boot. If I change optimization flags from -O to -O0 it works fine.
> I'm trying to isolate test case but it panics fairly early in boot process
> so it's not easy. If somebody tracks clang development and aware of
> known issues that might cause it - please share.
> 
> So far I tried fix from this bug but it didn't help:
> http://llvm.org/bugs/show_bug.cgi?id=15581

I'm seeing a crash early on as well.  Is this the same one?

/boot/kernel/kernel data=0x404564+0x17c9f8 syms=[0x4+0x76a60+0x4+0x4bf98]
Hit [Enter] to boot immediately, or any other key for command prompt.
Booting [/boot/kernel/kernel]...               
Using DTB provided by U-Boot.
Kernel entry at 0x80200100...
Kernel args: (null)
KDB: debugger backends: ddb
KDB: current backend: ddb
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FreeBSD 10.0-CURRENT #0: Sun Apr 28 05:25:04 PDT 2013
    root at fci386.localdomain:/usr/home/tim/projects/crochet-rpi/work/obj/arm.armv6/usr/src/sys/BEAGLEBONE arm
FreeBSD clang version 3.3 (trunk 178860) 20130405
WARNING: WITNESS option enabled, expect reduced performance.
panic: acquiring blockable sleep lock with spinlock or critical section held (rw) pmap pv global @ /usr/src/sys/arm/arm/pmap-v6.c:1187
KDB: enter: panic
[ thread pid 0 tid 0 ]
Stopped at      $d:     ldrb    r15, [r15, r15, ror r15]!
db>