Messages in this thread | | | From | Andi Kleen <> | Subject | Re: Cleanup possibility in asm-i386/string.h | Date | Tue, 7 Feb 2006 13:08:59 +0100 |
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On Tuesday 07 February 2006 13:00, Roman Zippel wrote: > Hi, > > On Tue, 7 Feb 2006, Andi Kleen wrote: > > > If you feel the need to remove some more code: Now that gcc 2.95 isn't supported > > anymore there isn't really a need to keep the handwritten inline string functions > > in asm-i386/string.h around. Just declaring them as normal externs will cause > > gcc to use its builtin expansions, which are typically better than these old inline > > functions with inline assembly. > > > > For out of line the C versions in lib/string.c can be used (by not setting __ARCH_*) > > x86-64 did it like this forever and I guess it would be valuable cleanup for i386 too. > > The only problem is that we compile with -ffreestanding which implies > -fno-builtin, so just declaring them as normal externs is not enough and > you have to something like this: > > #define __HAVE_ARCH_MEMSET > extern void *memset(void *, int, __kernel_size_t); > #define memset(d, c, n) __builtin_memset(d, c, n) > > (BTW you do this already in x86-64.)
Yes thinking about it the x86-64 string.h could just be copied over to i386. It should already do everything correctly and I don't think there is anything really 64bit specific in there.
> Another problem here is because of -fno-builtin it's not easy to use the > generic functions as fallback. x86-64 basically does this: > > #define strlen __builtin_strlen > size_t strlen(const char * s); > > #ifndef __HAVE_ARCH_STRLEN > extern __kernel_size_t strlen(const char *); > #endif > > This means you define a prototype for the builtin function and not for the > normal function. I'm not sure this is really intended.
What good would be a prototype for a symbol that is defined to a different symbol?
-Andi
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