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Re: recent breakage on mips: hash.c?
cgd@broadcom.com wrote:
>
> At Fri, 21 Jun 2002 15:49:10 -0400, J. Johnston wrote:
> > > > Looks like this would normally be defined by
> > > > libc/include/sys/param.h because of __IEEE_{BIG,LITTLE}_ENDIAN.
> > > >
> > > > In turn, those are defined in one of:
> > > >
> > > > ./libc/include/machine/ieeefp.h
> > > > ./libc/include/sys/config.h
> > > >
> > > > it looks like MIPS currently only has the macros defined in the
> > > > former. The latter has the comment:
> > [ ... ]
> > > I have a patch which I am testing as we speak. I have placed a default setting in
> > > sys/param.h based on whether sys/config.h sets BYTE_ORDER or not. The same default
> > > setting goes in hash.h in libc/search. Both are protected. This seems to remove the
> > > problem and avoid conflict with Cygwin that defines BYTE_ORDER or the other systems that
> > > provide sys/param.h.
> > >
> > > I will repost when my testing is completed and the patch is applied.
> > >
> >
> > Patches applied.
>
> So, I just got a chance to look at this patch, and looked at the
> related code some more.
>
> yes, the generic param.h now defines BYTE_ORDER depending on whether
> __IEEE_LITTLE_ENDIAN is defined, but, to my mind, there are some
> issues:
>
> (1) I'd still like to understand the need for duplication between
> ieeefp.h and config.h to begin with... 8-)
>
Historical mess :) One of those todo's that always falls off the bottom of my list. I'll finally look at including <machine/ieeefp.h> from
<sys/config.h> and removing the redundant bits after
this patch is evaluated/checked in.
> (2) mips, in particular, seems to still need changes to sys/param.h to
> have the right thing happen. (i.e., you fixed a problem, but it
> wasn't the one I reported, and didn't give me a clue whether my
> proposed solution to the original problem was correct.
>
It might have been clearer had I not forgotten to also copy over the MIPS stuff like you
requested. :(
> (3) the change you made even further muddies the water when config.h
> erroneously fails to set either of __IEEE_{BIG,LITTLE}_ENDIAN:
> now, you get a setting which causes the code to compile (probably)
> but may not be correct.
>
The check should actually be in <sys/config.h> like it is for <machine/ieeefp.h> so
all code doesn't constantly have to be checking this. This is minor change.
> (4) I notice that the libc/search code checks for the define
> _IEEE_LITTLE_ENDIAN (not one leaing underscore rather than 2!),
> which doens't seem correct, esp. in light of the fact that
> BYTE_ORDER is the "right thing" to use, right?
>
Good catch on the single underscore. BYTE_ORDER would be the consistent thing
to use since it used elsewhere.
> (5) the DB code (at least, if it's the same DB code I'm used to 8-)
> uses values for BIG_ENDIAN and LITTLE_ENDIAN _in its on-disk data
> structures_, and it's not good to have those differ from system to
> system. It's not immediately clear to me whether any of the
> libc/search bits will end up anyplace but in memory.
>
Reasonable.
> Based on those, I'd propose the following patch. I've not yet tested
> it (in progress for mips-elf and a few others), but i'd like some
> feedback on it anyway.
>
> Specifically it does the following:
>
> * addresses (2), (4).
>
> * errors out instead of silently doing the possibly-wrong thing for
> (3). Note that this will almost certainly break for sysvi386, but i
> believe it was not previously correct: its param.h doesn't define
> BYTE_ORDER, but the default for the hash code was big-endian... So,
> now it'll actually error out rather than compiling w/ an
> ... unexpected setting.
>
> * addresses (5) by renaming the byte-order-related constants that DB
> uses, in order to preserve their intended uses.
>
Looks good Chris. Repost when you have finished your testing.
-- Jeff J.
> cgd
> ==============================================================================
> 2002-06-25 Chris Demetriou <cgd@broadcom.com>
>
> * libc/include/sys/config.h (__IEEE_LITTLE_ENDIAN)
> (__IEEE_BIG_ENDIAN): Define appropriately for MIPS.
> * libc/include/sys/param.h (BYTE_ORDER): If BYTE_ORDER is
> not defined, verify that one of __IEEE_LITTLE_ENDIAN and
> __IEEE_BIG_ENDIAN are set.
> * libc/search/hash.h (DB_BYTE_ORDER, DB_BIG_ENDIAN)
> (DB_LITTLE_ENDIAN): New defines.
> * libc/search/hash.c: Replace all incorrect checks for
> _IEEE_LITTLE_ENDIAN with tests of BYTE_ORDER, and all uses of
> BYTE_ORDER, LITTLE_ENDIAN, and BIG_ENDIAN with DB_* versions.
> * libc/search/hash_page.c: Likewise.
>
> Index: libc/include/sys/config.h
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/include/sys/config.h,v
> retrieving revision 1.20
> diff -u -p -r1.20 config.h
> --- libc/include/sys/config.h 21 Jun 2002 18:40:48 -0000 1.20
> +++ libc/include/sys/config.h 25 Jun 2002 19:41:02 -0000
> @@ -82,6 +82,13 @@
> #define __IEEE_LITTLE_ENDIAN
> #endif
>
> +#ifdef __MIPSEL__
> +#define __IEEE_LITTLE_ENDIAN
> +#endif
> +#ifdef __MIPSEB__
> +#define __IEEE_BIG_ENDIAN
> +#endif
> +
> #ifdef __MMIX__
> #define __IEEE_BIG_ENDIAN
> #endif
> Index: libc/include/sys/param.h
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/include/sys/param.h,v
> retrieving revision 1.3
> diff -u -p -r1.3 param.h
> --- libc/include/sys/param.h 21 Jun 2002 18:15:53 -0000 1.3
> +++ libc/include/sys/param.h 25 Jun 2002 19:41:02 -0000
> @@ -19,11 +19,18 @@
> # define PATHSIZE (1024)
>
> #ifndef BYTE_ORDER
> +
> +/* Check that sys/config.h defined the endianness for us. */
> +#if !defined(__IEEE_BIG_ENDIAN) && !defined(__IEEE_LITTLE_ENDIAN)
> +#error sys/config.h must define one of __IEEE_BIG_ENDIAN and __IEEE_LITTLE_ENDIAN
> +#endif
> +
> #ifdef __IEEE_LITTLE_ENDIAN
> #define BYTE_ORDER LITTLE_ENDIAN
> #else
> #define BYTE_ORDER BIG_ENDIAN
> #endif
> -#endif
> +
> +#endif /* BYTE_ORDER */
>
> #endif
> Index: libc/search/hash.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/search/hash.c,v
> retrieving revision 1.2
> diff -u -p -r1.2 hash.c
> --- libc/search/hash.c 24 Jun 2002 23:05:08 -0000 1.2
> +++ libc/search/hash.c 25 Jun 2002 19:41:03 -0000
> @@ -72,7 +72,7 @@ static int hash_sync(const DB *, __uin
> static int hdestroy(HTAB *);
> static HTAB *init_hash(HTAB *, const char *, HASHINFO *);
> static int init_htab(HTAB *, int);
> -#ifdef _IEEE_LITTLE_ENDIAN
> +#if (BYTE_ORDER == LITTLE_ENDIAN)
> static void swap_header(HTAB *);
> static void swap_header_copy(HASHHDR *, HASHHDR *);
> #endif
> @@ -156,7 +156,7 @@ __hash_open(file, flags, mode, info, dfl
> hashp->hash = __default_hash;
>
> hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
> -#ifdef _IEEE_LITTLE_ENDIAN
> +#if (BYTE_ORDER == LITTLE_ENDIAN)
> swap_header(hashp);
> #endif
> if (hdrsize == -1)
> @@ -299,7 +299,7 @@ init_hash(hashp, file, info)
>
> nelem = 1;
> hashp->NKEYS = 0;
> - hashp->LORDER = BYTE_ORDER;
> + hashp->LORDER = DB_BYTE_ORDER;
> hashp->BSIZE = DEF_BUCKET_SIZE;
> hashp->BSHIFT = DEF_BUCKET_SHIFT;
> hashp->SGSIZE = DEF_SEGSIZE;
> @@ -335,8 +335,8 @@ init_hash(hashp, file, info)
> if (info->nelem)
> nelem = info->nelem;
> if (info->lorder) {
> - if (info->lorder != BIG_ENDIAN &&
> - info->lorder != LITTLE_ENDIAN) {
> + if (info->lorder != DB_BIG_ENDIAN &&
> + info->lorder != DB_LITTLE_ENDIAN) {
> errno = EINVAL;
> return (NULL);
> }
> @@ -495,7 +495,7 @@ flush_meta(hashp)
> HTAB *hashp;
> {
> HASHHDR *whdrp;
> -#ifdef _IEEE_LITTLE_ENDIAN
> +#if (BYTE_ORDER == LITTLE_ENDIAN)
> HASHHDR whdr;
> #endif
> int fp, i, wsize;
> @@ -508,7 +508,7 @@ flush_meta(hashp)
>
> fp = hashp->fp;
> whdrp = &hashp->hdr;
> -#ifdef _IEEE_LITTLE_ENDIAN
> +#if (BYTE_ORDER == LITTLE_ENDIAN)
> whdrp = &whdr;
> swap_header_copy(&hashp->hdr, whdrp);
> #endif
> @@ -941,7 +941,7 @@ alloc_segs(hashp, nsegs)
> return (0);
> }
>
> -#ifdef _IEEE_LITTLE_ENDIAN
> +#if (BYTE_ORDER == LITTLE_ENDIAN)
> /*
> * Hashp->hdr needs to be byteswapped.
> */
> Index: libc/search/hash.h
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/search/hash.h,v
> retrieving revision 1.3
> diff -u -p -r1.3 hash.h
> --- libc/search/hash.h 21 Jun 2002 19:09:50 -0000 1.3
> +++ libc/search/hash.h 25 Jun 2002 19:41:03 -0000
> @@ -39,18 +39,18 @@
>
> #include <sys/param.h>
>
> +/* Check that newlib understands the byte order of its target system. */
> #ifndef BYTE_ORDER
> -#ifndef LITTLE_ENDIAN
> -#define LITTLE_ENDIAN 1234
> +#error BYTE_ORDER not defined by sys/param.h
> #endif
> -#ifndef BIG_ENDIAN
> -#define BIG_ENDIAN 4321
> -#endif
> -#ifdef __IEEE_LITTLE_ENDIAN
> -#define BYTE_ORDER LITTLE_ENDIAN
> +
> +/* Define DB endianness constants based on target endianness. */
> +#define DB_LITTLE_ENDIAN 1234
> +#define DB_BIG_ENDIAN 4321
> +#if (BYTE_ORDER == LITTLE_ENDIAN)
> +#define DB_BYTE_ORDER DB_LITTLE_ENDIAN
> #else
> -#define BYTE_ORDER BIG_ENDIAN
> -#endif
> +#define DB_BYTE_ORDER DB_BIG_ENDIAN
> #endif
>
> /* Operations */
> Index: libc/search/hash_page.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/search/hash_page.c,v
> retrieving revision 1.2
> diff -u -p -r1.2 hash_page.c
> --- libc/search/hash_page.c 24 Jun 2002 23:05:08 -0000 1.2
> +++ libc/search/hash_page.c 25 Jun 2002 19:41:03 -0000
> @@ -552,7 +552,7 @@ __get_page(hashp, p, bucket, is_bucket,
> if (!is_bitmap && !bp[0]) {
> PAGE_INIT(p);
> } else
> - if (hashp->LORDER != BYTE_ORDER) {
> + if (hashp->LORDER != DB_BYTE_ORDER) {
> int i, max;
>
> if (is_bitmap) {
> @@ -591,7 +591,7 @@ __put_page(hashp, p, bucket, is_bucket,
> return (-1);
> fd = hashp->fp;
>
> - if (hashp->LORDER != BYTE_ORDER) {
> + if (hashp->LORDER != DB_BYTE_ORDER) {
> int i;
> int max;
>