On Fri, Feb 17, 2017 at 11:30:29PM -0700, Sandra Loosemore wrote:
> >
> >+@item prolog_pad
> >+@cindex @code{prolog_pad} function attribute
>
> I'm only a documentation maintainer so this is out of my area of
> responsibility, but I really wish we could rename the attribute and
> command-line option. Per
>
> per https://gcc.gnu.org/codingconventions.html#Spelling
>
> the correct spelling is "prologue".
>
> >+@cindex extra NOP instructions at the function entry point
> >+In case the target's text segment can be made writable at run time
> >+by any means, padding the function entry with a number of NOPs can
> >+be used to provide a universal tool for instrumentation. Usually,
> >+prolog padding is enabled globally using the @option{-fprolog-pad=N,M}
>
> definitely s/prolog/prologue/ in the running text here.
Well, you're definitely right in both cases.
About 400 occurrences of "prolog" in the source without ChangeLogs,
mainly in gcc/tree-vect-loop-manip.c and in libgcc/config/libbid/bid_conf.h;
about 3000 lines with "prologue". However there is a "-mprolog-function"
switch. One might call this a broken window. I don't want to contribute
to that.
However, writing some more documentation and being asked for clarity,
I found it more depicting to talk about the function entry point than
about the prologue. Also, this is about generic instrumentation, and it
surely involves NOPs.
So, hereby I'd like to start a small poll for a good name for this feature.
Anyone with a better idea please speak up now. Otherwise I'll just
s/prolog/prologue/g.
> The amount of space reserved is expressed as the number of NOP instructions
> to insert. On targets that have multiple instruction sizes, typically the
> smallest NOP instruction available for the current CPU mode is used to
> achieve the finest granularity.
I've made another improvement which makes the code even more robust now.
+DEF_TARGET_INSN (nop, (void))
In gcc/target-insns.def. This way I can easily check whether there is a
(define_insn "nop" ...) in the target md. Currently, all CPUs have it, but
who knows.
This will also be the default instruction used (It can be overridden
in the terget hook), so that rule has changed.
So, before the next version, any clever name suggestions?
Torsten
