Re: [Qemu-devel] [PATCH 11/13] tcg: sync globals for pure helpers instead of saving them

[Richard Henderson <rth@twiddle.net>]

On 09/27/2012 01:34 PM, Aurelien Jarno wrote:
>> (1) Helper may read globals.  Sometimes indirectly via exception.
>>     Implies that globals must be synced, but may remain in REG/CONST state.
> 
> I actually do wonder if we shouldn't use a different flag for "may
> trigger exception", even if we end-up handling it the same way as "may
> read globals". I am not sure it would be clear without knowledge of the
> QEMU internals that a function triggering exceptions should be flagged
> as "read globals".

I agree it is better to have a "may trigger exception" flag
if for nothing else besides documentation.

> Given the default is READG | WRITEG, it would be difficult to do that
> unless we negate the flags. Actually NOWRITEG, NOREADG, NOSIDE might be
> a good way to go, and is more consistent that by default nothing should
> be implied.

Sure.


r~