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*From*: Alan Modra <amodra at bigpond dot net dot au>*To*: DJ Delorie <dj at redhat dot com>*Cc*: binutils at sources dot redhat dot com*Date*: Wed, 3 May 2006 13:14:39 +0930*Subject*: Re: [patch] expanding tables for bfd/hash.c*References*: <200605011937.k41Jbeuq029555@greed.delorie.com> <20060502072229.GK11597@bubble.grove.modra.org> <200605030116.k431GXNW019776@greed.delorie.com>

On Tue, May 02, 2006 at 09:16:33PM -0400, DJ Delorie wrote: > > > Are you offering to fix all the testsuite? > > Yes, let me know which break and I'll rearrange the expected results > to match the new ordering. A quicker alternative might be to leave the default unchanged. There are a lot of tests that depend on symbol table order, and some only run natively. A simple change that accomplishes this is to depopulate primes[], which might be a good idea in itself. What is the point in growing a table from 7 to 13? You'd probably be better off growing to something quite a lot larger, at least when the size is relatively small. How about this? * hash.c (DEFAULT_SIZE): Revert last change. (higher_prime_number): Correct test for no larger prime. Don't abort on error, instead return 0. Depopulate primes[]. (bfd_hash_lookup): If we overflow size, refuse to grow table. Index: bfd/hash.c =================================================================== RCS file: /cvs/src/src/bfd/hash.c,v retrieving revision 1.21 diff -u -p -r1.21 hash.c --- bfd/hash.c 1 May 2006 19:36:27 -0000 1.21 +++ bfd/hash.c 3 May 2006 03:43:05 -0000 @@ -298,10 +298,11 @@ SUBSUBSECTION */ /* The default number of entries to use when creating a hash table. */ -#define DEFAULT_SIZE (4093) +#define DEFAULT_SIZE 4051 /* The following function returns a nearest prime number which is - greater than N, and near a power of two. Copied from libiberty. */ + greater than N, and near a power of two. Copied from libiberty. + Returns zero for ridiculously large N to signify an error. */ static unsigned long higher_prime_number (unsigned long n) @@ -309,20 +310,8 @@ higher_prime_number (unsigned long n) /* These are primes that are near, but slightly smaller than, a power of two. */ static const unsigned long primes[] = { - (unsigned long) 7, - (unsigned long) 13, - (unsigned long) 31, - (unsigned long) 61, - (unsigned long) 127, - (unsigned long) 251, (unsigned long) 509, - (unsigned long) 1021, - (unsigned long) 2039, - (unsigned long) 4093, (unsigned long) 8191, - (unsigned long) 16381, - (unsigned long) 32749, - (unsigned long) 65521, (unsigned long) 131071, (unsigned long) 262139, (unsigned long) 524287, @@ -343,7 +332,7 @@ higher_prime_number (unsigned long n) }; const unsigned long *low = &primes[0]; - const unsigned long *high = &primes[sizeof(primes) / sizeof(primes[0])]; + const unsigned long *high = &primes[sizeof (primes) / sizeof (primes[0])]; while (low != high) { @@ -354,12 +343,8 @@ higher_prime_number (unsigned long n) high = mid; } - /* If we've run out of primes, abort. */ - if (n > *low) - { - fprintf (stderr, "Cannot find prime bigger than %lu\n", n); - abort (); - } + if (n >= *low) + return 0; return *low; } @@ -486,12 +471,19 @@ bfd_hash_lookup (struct bfd_hash_table * if (table->count > table->size * 3 / 4) { - int newsize = higher_prime_number (table->size); + unsigned long newsize = higher_prime_number (table->size); struct bfd_hash_entry **newtable; unsigned int hi; - unsigned int alloc; + unsigned long alloc = newsize * sizeof (struct bfd_hash_entry *); - alloc = newsize * sizeof (struct bfd_hash_entry *); + /* If we can't find a higher prime, or we can't possibly alloc + that much memory, don't try to grow the table. */ + if (newsize == 0 || alloc / sizeof (struct bfd_hash_entry *) != newsize) + { + /* Lie. Stops us trying to grow again for a while. */ + table->count = 0; + return hashp; + } newtable = ((struct bfd_hash_entry **) objalloc_alloc ((struct objalloc *) table->memory, alloc)); -- Alan Modra IBM OzLabs - Linux Technology Centre

**Follow-Ups**:**Re: [patch] expanding tables for bfd/hash.c***From:*DJ Delorie

**References**:**[patch] expanding tables for bfd/hash.c***From:*DJ Delorie

**Re: [patch] expanding tables for bfd/hash.c***From:*Alan Modra

**Re: [patch] expanding tables for bfd/hash.c***From:*DJ Delorie

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