Re: [patch 0/2] Immediate Values - jump patching update

[H. Peter Anvin]

Mathieu Desnoyers wrote:
> Peter, do you have something like the following code in mind ?

Basically, although I was suggesting using a per-site dynamic piece of 
code.  Data items may not necessarily be in registers.

> I think the main differences between the code snippet down here and the
> markers is that markers rely on the compiler to generate the stack
> setup, and have this code a little bit closer to the function than what
> I propose here, where I put the stack setup code in a "farfaraway"
> section.  Moreover, markers are much simpler than what I show here.
> And actually, markers can be deployed portably, with
> architecture-specific optimizations refined later. This has to be
> implemented all up front for any traced architecture. In addition,
> dealing with weird types like unsigned long long can become a pain.
> Also, due to fact that we are asking the compiler to put keep some
> variables live in registers, I would be tempted to embed this in a block
> controlled by an if() statement (conditional branch, like I use for the
> markers) so we don't have to pay the penality of populating the
> registers when not required if there are not live at the marker site.

We're requesting to keep them *alive*, but not necessarily in registers 
(that would be an "r" constraint.)

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/