asr(4) error with new clang/llvm

[Scott Long]

> On Jan 2, 2015, at 12:00 AM, Ed Maste <emaste at freebsd.org> wrote:
> 
> On 1 January 2015 at 23:13, Steven Hartland <killing at multiplay.co.uk> wrote:
>> 
>> On 02/01/2015 01:23, Bjoern A. Zeeb wrote:
>>> 
>>> Hi,
>>> 
>>> you need the next line of source to see that while the union only defines
>>> Simple[1], the comparison goes up to SG_LIST (or something) which is indeed
>>> defined as 58.   Cn someone fix this?   This makes i386 compiles failing
>>> currently.
>>> 
>>> /scratch/tmp/bz/head.svn/sys/modules/asr/../../dev/asr/asr.c:1849:29:
>>> error: array index 58 is past the end of the array (which contains 1
>>> element) [-Werror,-Warray-bounds]
>>>         while ((len > 0) && (sg < &((PPRIVATE_SCSI_SCB_EXECUTE_MESSAGE)
>>>                                    ^
>>> /scratch/tmp/bz/head.svn/sys/dev/asr/i2omsg.h:934:8: note: array 'Simple'
>>> declared here
>>>        I2O_SGE_SIMPLE_ELEMENT              Simple[1];
>>>        ^
>> 
>> If that's wrong it looks like there's also a number of calls to the macro
>> SG(SGL,Index,Flags,Buffer,Size)  which are also wrong as Index is used in
>> the same way:
>> &(((PI2O_SG_ELEMENT)(SGL))->u.Simple[Index]
>> 
>> There appears to be two calls to SG where Index is 1.
>> 
>> I'm afraid I have no idea what the fix would be as the entire driver is very
>> voodoo like to me :(
> 
> It's a variable length array in a struct / union. Other than being
> confusing and now triggering a warning after the clang update it
> should be fine.
> 
> Most likely we need to build asr with -Werror disabled for that
> warning, perhaps -Wno-error-array-bounds. I'll take a look tomorrow
> morning if nobody else gets to it first.
> 

I got to it first ;-)

Scott