Enable custom bcache hash function. 2010-08-18 Sami Wagiaalla * psymtab.c (add_psymbol_to_bcache): Remove 'static' from 'static partial_symbol psymbol'. (psymbol_hash): New function. (psymbol_compare): New function. * bcache.c (hash_continue): New. (hash): Use hash_continue. * bcache.c: Add hash_function and compare_function pointers to bcache struct. (bcache_full): Use bcache->hash_function, and bcache->compare_function. (bcache_compare): New function. (bcache_xmalloc): Take hash_function and compare_function arguments and initialize the bcach's pointers. Updated comment. * objfiles.c (allocate_objfile): Updated. * symfile.c (reread_symbols): Updated. diff --git a/gdb/bcache.c b/gdb/bcache.c index 7d9180c..ea408ab 100644 --- a/gdb/bcache.c +++ b/gdb/bcache.c @@ -89,6 +89,12 @@ struct bcache 16 bits of hash values) hit, but the corresponding combined length/data compare missed. */ unsigned long half_hash_miss_count; + + /* Hash function to be used for this bcache object. */ + unsigned long (*hash_function)(const void *addr, int length); + + /* Compare function to be used for this bcache object. */ + int (*compare_function)(const void*, const void*, int length); }; /* The old hash function was stolen from SDBM. This is what DB 3.0 uses now, @@ -98,12 +104,19 @@ struct bcache unsigned long hash(const void *addr, int length) { + return hash_continue (addr, length, 0); +} + +/* Continue the calculation of the hash H at the given address. */ + +unsigned long +hash_continue (const void *addr, int length, unsigned long h) +{ const unsigned char *k, *e; - unsigned long h; k = (const unsigned char *)addr; e = k+length; - for (h=0; k< e;++k) + for (; k< e;++k) { h *=16777619; h ^= *k; @@ -235,7 +248,8 @@ bcache_full (const void *addr, int length, struct bcache *bcache, int *added) bcache->total_count++; bcache->total_size += length; - full_hash = hash (addr, length); + full_hash = bcache->hash_function (addr, length); + half_hash = (full_hash >> 16); hash_index = full_hash % bcache->num_buckets; @@ -247,7 +261,7 @@ bcache_full (const void *addr, int length, struct bcache *bcache, int *added) if (s->half_hash == half_hash) { if (s->length == length - && ! memcmp (&s->d.data, addr, length)) + && bcache->compare_function (&s->d.data, addr, length)) return &s->d.data; else bcache->half_hash_miss_count++; @@ -276,14 +290,42 @@ bcache_full (const void *addr, int length, struct bcache *bcache, int *added) } } + +/* Compare the byte string at ADDR1 of lenght LENGHT to the + string at ADDR2. Return 1 if they are equal. */ + +static int +bcache_compare (const void* addr1, const void* addr2, int length) +{ + return memcmp (addr1, addr2, length) == 0; +} + +/* Forwarding function for memcmp. */ +//bcache_memcmp () + /* Allocating and freeing bcaches. */ +/* Allocated a bcache. HASH_FUNCTION and COMPARE_FUNCTION can be used + to pass in custom hash, and compare functions to be used by this + bcache. If HASH_FUNCTION is NULL hash() is used and if COMPARE_FUNCTION + is NULL memcmp() is used. */ + struct bcache * -bcache_xmalloc (void) +bcache_xmalloc (unsigned long (*hash_function)(const void*, int length), + int (*compare_function)(const void*, const void*, int length)) { /* Allocate the bcache pre-zeroed. */ struct bcache *b = XCALLOC (1, struct bcache); + if (hash_function) + b->hash_function = hash_function; + else + b->hash_function = hash; + + if (compare_function) + b->compare_function = compare_function; + else + b->compare_function = bcache_compare; return b; } diff --git a/gdb/bcache.h b/gdb/bcache.h index da69a2d..97fd417 100644 --- a/gdb/bcache.h +++ b/gdb/bcache.h @@ -158,7 +158,9 @@ extern const void *bcache_full (const void *addr, int length, extern void bcache_xfree (struct bcache *bcache); /* Create a new bcache object. */ -extern struct bcache *bcache_xmalloc (void); +extern struct bcache *bcache_xmalloc ( + unsigned long (*hash_function)(const void*, int length), + int (*compare_function)(const void*, const void*, int length)); /* Print statistics on BCACHE's memory usage and efficacity at eliminating duplication. TYPE should be a string describing the @@ -167,7 +169,9 @@ extern struct bcache *bcache_xmalloc (void); extern void print_bcache_statistics (struct bcache *bcache, char *type); extern int bcache_memory_used (struct bcache *bcache); -/* The hash function */ +/* The hash functions */ extern unsigned long hash(const void *addr, int length); +extern unsigned long hash_continue (const void *addr, int length, + unsigned long h); #endif /* BCACHE_H */ diff --git a/gdb/objfiles.c b/gdb/objfiles.c index b522189..c479d22 100644 --- a/gdb/objfiles.c +++ b/gdb/objfiles.c @@ -199,9 +199,9 @@ allocate_objfile (bfd *abfd, int flags) struct objfile *objfile; objfile = (struct objfile *) xzalloc (sizeof (struct objfile)); - objfile->psymbol_cache = bcache_xmalloc (); - objfile->macro_cache = bcache_xmalloc (); - objfile->filename_cache = bcache_xmalloc (); + objfile->psymbol_cache = bcache_xmalloc (psymbol_hash, psymbol_compare); + objfile->macro_cache = bcache_xmalloc (NULL, NULL); + objfile->filename_cache = bcache_xmalloc (NULL, NULL); /* We could use obstack_specify_allocation here instead, but gdb_obstack.h specifies the alloc/dealloc functions. */ obstack_init (&objfile->objfile_obstack); diff --git a/gdb/psymtab.c b/gdb/psymtab.c index bc47681..0d57b5e 100644 --- a/gdb/psymtab.c +++ b/gdb/psymtab.c @@ -1270,6 +1270,47 @@ start_psymtab_common (struct objfile *objfile, return (psymtab); } +/* Calculate a hash code for the given partial symbol. The hash is + calculated using the symbol's value, language, domain, class + and name. These are the values which are set by + add_psymbol_to_bcache. */ + +unsigned long +psymbol_hash (const void *addr, int length) +{ + unsigned long h = 0; + struct partial_symbol *psymbol = (struct partial_symbol *) addr; + unsigned int lang = psymbol->ginfo.language; + unsigned int domain = PSYMBOL_DOMAIN (psymbol); + unsigned int class = PSYMBOL_CLASS (psymbol); + + h = hash_continue (&psymbol->ginfo.value, sizeof (psymbol->ginfo.value), h); + h = hash_continue (&lang, sizeof (unsigned int), h); + h = hash_continue (&domain, sizeof (unsigned int), h); + h = hash_continue (&class, sizeof (unsigned int), h); + h = hash_continue (psymbol->ginfo.name, strlen (psymbol->ginfo.name), h); + + return h; +} + +/* Returns true if the symbol at addr1 equals the symbol at addr2. + For the comparison this function uses a symbols value, + language, domain, class and name. */ + +int +psymbol_compare (const void *addr1, const void *addr2, int length) +{ + struct partial_symbol *sym1 = (struct partial_symbol *) addr1; + struct partial_symbol *sym2 = (struct partial_symbol *) addr2; + + return (memcmp (&sym1->ginfo.value, &sym1->ginfo.value, + sizeof (sym1->ginfo.value)) == 0 + && sym1->ginfo.language == sym2->ginfo.language + && PSYMBOL_DOMAIN (sym1) == PSYMBOL_DOMAIN (sym2) + && PSYMBOL_CLASS (sym1) == PSYMBOL_CLASS (sym2) + && sym1->ginfo.name == sym2->ginfo.name); +} + /* Helper function, initialises partial symbol structure and stashes it into objfile's bcache. Note that our caching mechanism will use all fields of struct partial_symbol to determine hash value of the @@ -1288,7 +1329,7 @@ add_psymbol_to_bcache (char *name, int namelength, int copy_name, /* psymbol is static so that there will be no uninitialized gaps in the structure which might contain random data, causing cache misses in bcache. */ - static struct partial_symbol psymbol; + struct partial_symbol psymbol; /* However, we must ensure that the entire 'value' field has been zeroed before assigning to it, because an assignment may not diff --git a/gdb/psymtab.h b/gdb/psymtab.h index de8b67e..0786944 100644 --- a/gdb/psymtab.h +++ b/gdb/psymtab.h @@ -20,6 +20,9 @@ #ifndef PSYMTAB_H #define PSYMTAB_H +extern unsigned long psymbol_hash (const void *addr, int length); +extern int psymbol_compare (const void *addr1, const void *addr2, int length); + void map_partial_symbol_names (void (*) (const char *, void *), void *); void map_partial_symbol_filenames (void (*) (const char *, const char *, diff --git a/gdb/symfile.c b/gdb/symfile.c index 2cb6b7f..048b8a8 100644 --- a/gdb/symfile.c +++ b/gdb/symfile.c @@ -2432,11 +2432,12 @@ reread_symbols (void) /* Free the obstacks for non-reusable objfiles */ bcache_xfree (objfile->psymbol_cache); - objfile->psymbol_cache = bcache_xmalloc (); + objfile->psymbol_cache = bcache_xmalloc (psymbol_hash, + psymbol_compare); bcache_xfree (objfile->macro_cache); - objfile->macro_cache = bcache_xmalloc (); + objfile->macro_cache = bcache_xmalloc (NULL, NULL); bcache_xfree (objfile->filename_cache); - objfile->filename_cache = bcache_xmalloc (); + objfile->filename_cache = bcache_xmalloc (NULL,NULL); if (objfile->demangled_names_hash != NULL) { htab_delete (objfile->demangled_names_hash); @@ -2458,9 +2459,10 @@ reread_symbols (void) memset (&objfile->msymbol_demangled_hash, 0, sizeof (objfile->msymbol_demangled_hash)); - objfile->psymbol_cache = bcache_xmalloc (); - objfile->macro_cache = bcache_xmalloc (); - objfile->filename_cache = bcache_xmalloc (); + objfile->psymbol_cache = bcache_xmalloc (psymbol_hash, + psymbol_compare); + objfile->macro_cache = bcache_xmalloc (NULL, NULL); + objfile->filename_cache = bcache_xmalloc (NULL, NULL); /* obstack_init also initializes the obstack so it is empty. We could use obstack_specify_allocation but gdb_obstack.h specifies the alloc/dealloc