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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] qemu vs gcc4
Date: Mon, 23 Oct 2006 13:20:07 +0100
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To: qemu-devel@nongnu.org

On Monday 23 October 2006 09:16, Martin Guy wrote:
> > Now, gcc4 can produce code with several return instructions (with no
> > option to turn that of, as far as I understand). You cannot cut them out,
> > and therefore you cannot chain the simple functions.
>
> ...unless you also map return instructions within the generated
> functions into branches to the soon-to-be-dropped final "return"? Not
> that I know anything about qemu internals mind u...

That's exactly what my gcc4 hacks do.

It gets complicated because a x86 uses variable length insn encodings so you 
don't know where insn boundaries are, and a jmp instruction is larger than a 
ret instruction so it's not always possible to do a straight replacement.

Paul