On Jun 6, 2008, at 5:36 PM, Quincey Morris wrote:
Thanks, and to Shawn for the same suggestion. It's a pragmatic
solution I can deal with.
A little inner voice insists on asking, though, how we know some
future version of the compiler might not optimize '[data self]'
upwards before the loop, if it decides that nothing inside the loop
references anything non-local:
NSData* data = <get it from somewhere>;
const unsigned char* bytes = [data bytes];
NSUInteger count = [data length];
NSUInteger largestByte = 0;
for (NSUInteger i = 0; i < count; i++)
largestByte = MAX (largestByte , bytes [i]);
[data self];
TBH, I don't see any real solution without making the compiler aware
of the GC consequences of its optimizations.
In this case, that wouldn't be a GC issue. Every invocation of an Objective-C -- every Obj-C call site -- is dynamically bound and, thus, dynamically dispatched. Thus, the call site can't be moved without risk that the application behavior will change.
For example, it would be possible to cause the above to change what [data self] means when a particular bytes[i] is read.
b.bum
smime.p7s
Description: S/MIME cryptographic signature
_______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
