On Tue, Sep 01, 2009 at 11:43:10PM +0800, Bean wrote: > On Tue, Sep 1, 2009 at 9:42 PM, Vladimir 'phcoder' > Serbinenko<phco...@gmail.com> wrote: > > Hello. NESTED_ATTR_FUNC was introduced 6 years ago to workaround a bug > > in compiler. Now it creates only problems. In particular if they are > > used wrong it creates a bug of argument passing. Such bugs are > > difficult to find because it usually results in strange behaviour and > > in grub-emu NESTED_FUNC_ATTR is exteneded to an empty string so gdb > > and valgrind can't detect any error. Should we perhaps remove it > > coupled with adding a requirement for at least gcc 4.2? Can I run > > s/NESTED_FUNC_ATTR//g; on entire codebase and remove corresponding > > entry in configure.ac? > > Hi, > > I make an assembly dump of the code generated by gcc-4.2. Apparently, > the "FIX" is achieved by ignoring the regparm attribute at all. > __attribute__ ((__regparm__ (3))) doesn't have any effect any more, it > always pass the parameters on the stack. This defeats the original > purpose of -mregparm=3, which passes parameters using register and > therefore reduce module size. In fact, if we are going to use stack, > we could just remove -mregparm=3 option, this works for all version of > gcc.
I have the impression that using stack isn't a good idea for GRUB, due to size and speed improvements, except in cases where we can't avoid it. If older versions of GCC ignore -mregparm, we need a configure check (I prefer one that checks for the feature itself, but a version check is also acceptable IMHO). -- Robert Millan The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and how) you may access your data; but nobody's threatening your freedom: we still allow you to remove your data and not access it at all." _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
