symbol_table: Prehash the key on insert, and reuse the entry on shadowing.

Mostly saves computing the hash twice, but while we're here there's no
need for shadowing to walk the table again.

Release Mesa build runtime of
KHR-Single-GL46.arrays_of_arrays_gl.SizedDeclarationsPrimitive -4.19869%
+/- 3.20231%

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22451>

diff --git a/src/mesa/program/symbol_table.c b/src/mesa/program/symbol_table.c
index e988af2..834baf8 100644 (file)
--- a/src/mesa/program/symbol_table.c
+++ b/src/mesa/program/symbol_table.c
@@ -176,7 +176,9 @@ _mesa_symbol_table_add_symbol(struct _mesa_symbol_table *table,
                               const char *name, void *declaration)
 {
    struct symbol *new_sym;
-   struct symbol *sym = find_symbol(table, name);
+   uint32_t hash = _mesa_hash_string(name);
+   struct hash_entry *entry = _mesa_hash_table_search_pre_hashed(table->ht, hash, name);
+   struct symbol *sym = entry ? entry->data : NULL;
 
    if (sym && sym->depth == table->depth)
       return -1;
@@ -191,9 +193,13 @@ _mesa_symbol_table_add_symbol(struct _mesa_symbol_table *table,
       /* Store link to symbol in outer scope with the same name */
       new_sym->next_with_same_name = sym;
       new_sym->name = sym->name;
+
+      entry->data = new_sym;
    } else {
       new_sym->name = (char *)(new_sym + 1);
       strcpy(new_sym->name, name);
+
+      _mesa_hash_table_insert_pre_hashed(table->ht, hash, new_sym->name, new_sym);
    }
 
    new_sym->next_with_same_scope = table->current_scope->symbols;
@@ -202,8 +208,6 @@ _mesa_symbol_table_add_symbol(struct _mesa_symbol_table *table,
 
    table->current_scope->symbols = new_sym;
 
-   _mesa_hash_table_insert(table->ht, new_sym->name, new_sym);
-
    return 0;
 }