Paolo Bonzini - [PATCH] Add pointer-map and traversal of pointer-set (original) (raw)

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• From: Paolo Bonzini
• To: GCC Patches
• Date: Thu, 07 Dec 2006 11:15:45 +0100
• Subject: [PATCH] Add pointer-map and traversal of pointer-set

I think this is a valuable addition to the bag of data structures in GCC.Bootstrapped/regtested i686-pc-linux-gnu, and widely used in my private branch.Ok for mainline? (I may work later on converting existing data structures to the new pointer_map).Paolo

2006-12-07 Paolo Bonzini bonzini@gnu.org

* pointer-set.c (insert_aux): Only return insertion slot.
(pointer_set_insert): Adjust.
(pointer_set_traverse, struct pointer_map_t, pointer_map_create,
pointer_map_destroy, pointer_map_insert, pointer_map_contains,
pointer_map_traverse): New.
* pointer-set.h (pointer_set_traverse, struct pointer_map_t,
pointer_map_create,  pointer_map_destroy, pointer_map_insert,
pointer_map_contains, pointer_map_traverse): Declare.

Index: pointer-set.c

--- pointer-set.c (revision 118179) +++ pointer-set.c (working copy) @@ -114,22 +114,16 @@ pointer_set_contains (struct pointer_set } } -/* Subroutine of pointer_set_insert. Inserts P into an empty - element of SLOTS, an array of length N_SLOTS. Returns nonzero - if P was already present in N_SLOTS. / -static int +/ Subroutine of pointer_set_insert. Return the insertion slot for P into + an empty element of SLOTS, an array of length N_SLOTS. */ +static inline size_t insert_aux (void *p, void **slots, size_t n_slots, size_t log_slots) { size_t n = hash1 (p, n_slots, log_slots); while (true) { - if (slots[n] == p) - return 1; - else if (slots[n] == 0) - { - slots[n] = p; - return 0; - } + if (slots[n] == p || slots[n] == 0) + return n; else { ++n; @@ -144,12 +138,10 @@ insert_aux (void *p, void **slots, size_ int pointer_set_insert (struct pointer_set_t *pset, void *p) { - if (insert_aux (p, pset->slots, pset->n_slots, pset->log_slots)) - return 1;

• /* We've inserted a new element. Expand the table if necessary to keep

• the load factor small.  */

• ++pset->n_elements;

• size_t n;
• /* For simplicity, expand the set even if P is already there. This can be

• superfluous but can happen at most once.  */

  if (pset->n_elements > pset->n_slots / 4) { size_t new_log_slots = pset->log_slots + 1;

@@ -158,9 +150,10 @@ pointer_set_insert (struct pointer_set_t size_t i; for (i = 0; i < pset->n_slots; ++i) - { - if (pset->slots[i]) - insert_aux (pset->slots[i], new_slots, new_n_slots, new_log_slots); + { + void value = pset->slots[i]; + n = insert_aux (value, new_slots, new_n_slots, new_log_slots); + new_slots[n] = value; } XDELETEVEC (pset->slots); @@ -169,5 +162,138 @@ pointer_set_insert (struct pointer_set_t pset->slots = new_slots; } + n = insert_aux (p, pset->slots, pset->n_slots, pset->log_slots); + if (pset->slots[n]) + return 1; + + pset->slots[n] = p; + ++pset->n_elements; return 0; } + +/ Pass each pointer in PSET to the function in FN, together with the fixed + parameter DATA. If FN returns false, the iteration stops. */ + +void pointer_set_traverse (struct pointer_set_t *pset, + bool (*fn) (void *, void *), void data) +{ + size_t i; + for (i = 0; i < pset->n_slots; ++i) + if (pset->slots[i] && !fn (pset->slots[i], data)) + break; +} + + +struct pointer_map_t +{ + size_t log_slots; + size_t n_slots; / n_slots = 2^log_slots */ + size_t n_elements; + + void **keys; + void *values; +}; + +/ Allocate an empty pointer map. */ +struct pointer_map_t * +pointer_map_create (void) +{ + struct pointer_map_t *result = XNEW (struct pointer_map_t); + + result->n_elements = 0; + result->log_slots = 8; + result->n_slots = (size_t) 1 << result->log_slots; + + result->keys = XCNEWVEC (void *, result->n_slots); + result->values = XCNEWVEC (void , result->n_slots); + return result; +} + +/ Reclaims all memory associated with PMAP. */ +void pointer_map_destroy (struct pointer_map_t pmap) +{ + XDELETEVEC (pmap->keys); + XDELETEVEC (pmap->values); + XDELETE (pmap); +} + +/ Returns a pointer to the value to which P maps, if PMAP contains P. P + must be nonnull. Return NULL if PMAP does not contain P. + + Collisions are resolved by linear probing. */ +void ** +pointer_map_contains (struct pointer_map_t *pmap, void p) +{ + size_t n = hash1 (p, pmap->n_slots, pmap->log_slots); + + while (true) + { + if (pmap->keys[n] == p) + return &pmap->values[n]; + else if (pmap->keys[n] == 0) + return NULL; + else + { + ++n; + if (n == pmap->n_slots) + n = 0; + } + } +} + +/ Inserts P into PMAP if it wasn't already there. Returns a pointer + to the value. P must be nonnull. */ +void ** +pointer_map_insert (struct pointer_map_t *pmap, void p) +{ + size_t n; + + / For simplicity, expand the map even if P is already there. This can be + superfluous but can happen at most once. */ + if (pmap->n_elements > pmap->n_slots / 4) + { + size_t new_log_slots = pmap->log_slots + 1; + size_t new_n_slots = pmap->n_slots * 2; + void **new_keys = XCNEWVEC (void *, new_n_slots); + void **new_values = XCNEWVEC (void *, new_n_slots); + size_t i; + + for (i = 0; i < pmap->n_slots; ++i) + if (pmap->keys[i]) + { + void key = pmap->keys[i]; + n = insert_aux (key, new_keys, new_n_slots, new_log_slots); + new_keys[n] = key; + new_values[n] = pmap->values[i]; + } + + XDELETEVEC (pmap->keys); + XDELETEVEC (pmap->values); + pmap->n_slots = new_n_slots; + pmap->log_slots = new_log_slots; + pmap->keys = new_keys; + pmap->values = new_values; + } + + n = insert_aux (p, pmap->keys, pmap->n_slots, pmap->log_slots); + if (!pmap->keys[n]) + { + ++pmap->n_elements; + pmap->keys[n] = p; + } + + return &pmap->values[n]; +} + +/ Pass each pointer in PMAP to the function in FN, together with the pointer + to the value and the fixed parameter DATA. If FN returns false, the + iteration stops. */ + +void pointer_map_traverse (struct pointer_map_t *pmap, + bool (*fn) (void *, void **, void *), void *data) +{ + size_t i; + for (i = 0; i < pmap->n_slots; ++i) + if (pmap->keys[i] && !fn (pmap->keys[i], &pmap->values[i], data)) + break; +} Index: pointer-set.h

--- pointer-set.h (revision 118179) +++ pointer-set.h (working copy) @@ -22,11 +22,21 @@ Software Foundation, 51 Franklin Street, #define POINTER_SET_H struct pointer_set_t;

struct pointer_set_t *pointer_set_create (void); void pointer_set_destroy (struct pointer_set_t *pset);

int pointer_set_contains (struct pointer_set_t *pset, void *p); int pointer_set_insert (struct pointer_set_t *pset, void *p); +void pointer_set_traverse (struct pointer_set_t , bool () (void *, void *), + void *); + +struct pointer_map_t; +struct pointer_map_t *pointer_map_create (void); +void pointer_map_destroy (struct pointer_map_t *pmap); + +void **pointer_map_contains (struct pointer_map_t *pmap, void *p); +void **pointer_map_insert (struct pointer_map_t *pmap, void *p); +void pointer_map_traverse (struct pointer_map_t , + bool () (void *, void **, void *), void *);

#endif /* POINTER_SET_H */