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Re: other/7114: ICE building strcoll.op from glibc-2.2.5
On Mon, Jul 15, 2002 at 09:31:24PM -0700, Richard Henderson wrote:
> On Tue, Jul 16, 2002 at 11:08:16AM +0930, Alan Modra wrote:
> > It gets worse. rs6000/sysv4.h sets PROFILE_BEFORE_PROLOGUE.
>
> Make rs6000/sysv4.h can use PROFILE_HOOK instead.
Aye, that's the nice way to do it. However, on powerpc64-linux,
I've had kernel people complaining that the profiling code isn't
what they want: All those register saves from the prologue
preceding the mcount call apparently are messing up accurate
count values, and it's hard for an mcount implementation to
adjust times, or so I'm told. I implemented a simple hack to
do PROFILE_BEFORE_PROLOGUE on powerpc64-linux for people who
want it.
I suspect we'll get the same sort of complaint if we change
powerpc mcount. There's also the issue that some special-purpose
mcount functions may expect to be called before the stack has
been adjusted.
I'm rapidly approaching the point where I either give up on this
problem, or simply remove support for profiling on nested
functions. The current code just doesn't work.