Re: Add support for the Win32 hook prologue (try 3)

[Paolo Bonzini <bonzini at gnu dot org>]

> I'd propose to have the function attrib the way it is, and add something
> similar to /hotpatch or /functionpadmin later if needed(e.g. reactos or mingw
> might be interested in that, but I don't think Wine will ever need it). That
> way Wine can more reliably generate code that Windows apps know how to hook.
>
> I'd be glad if a gcc maintainer could comment on that, so I know which way to
> go.

It is common to have both an attribute and a machine-specific option. 
There is no problem with that.

Regarding adding padding before the function it would be possible to 
implement it by defining the ASM_OUTPUT_FUNCTION_PREFIX macro.

Right now ASM_OUTPUT_FUNCTION_PREFIX is defined to be emitted *after* 
the alignment directive; for your purpose it would be best to call it 
before, so that it will keep the requested function alignment.  Luckily, 
ASM_OUTPUT_FUNCTION_PREFIX is unused, so you can move it as you wish 
(and possibly replace it with a target hook instead of using a macro).

Paolo