------- Comment #15 from rguenth at gcc dot gnu dot org 2010-05-29 14:45
-------
(In reply to comment #13)
> (In reply to comment #10)
> > Or rather, if you have
> >
> > void __attribute__((naked)) foo (int i)
> > {
> > asm("use i");
> > }
> >
> > without any inputs refering to i that is invalid.
>
> Not according to gcc/doc/extend.texi:
>
> > @item naked
> > @cindex function without a prologue/epilogue code
> > Use this attribute on the ARM, AVR, IP2K, RX and SPU ports to indicate that
> > the specified function does not need prologue/epilogue sequences generated
> > by
> > the compiler. It is up to the programmer to provide these sequences. The
> > only statements that can be safely included in naked functions are
> > @code{asm} statements that do not have operands.
>
> Note: "do not have operands". Thus the only way such an asm() can refer to
> parameters is by assuming a standard function call sequence and hardcoding
> corresponding register numbers or stack frame offsets.
Then the target has to properly communicate this to the middle-end.
> However, even if the asm() refers to those parameters via "r"(...) inputs,
> gcc-4.5 changes the register assignment to not agree with the standard call
> sequence, I'll attach a small test case showing that in a moment.
I'd have required dummy inputs like "g" (kto), "g" (kfrom) not used by
the actual assembly.
For now re-open as a target bug.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|INVALID |
Summary|[4.5 Regression] arm linux |[4.5 Regression] __naked
|kernel crahes when built |attribute is broken
|with -fipa-sra, __naked |
|attribute is broken |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290
