gallium: Conditional debugging output.

Generalize the conditional debugging output code found trhought the gallium
drivers.

src/gallium/auxiliary/util/p_debug.c

@@ -103,3 +103,37 @@ void debug_assert_fail(const char *expr, const char *file, unsigned line)
    debug_printf("%s:%i: Assertion `%s' failed.\n", file, line, expr);
    debug_break();
 }
+
+
+#define DEBUG_MASK_TABLE_SIZE 256
+
+
+/**
+ * Mask hash table.
+ * 
+ * For now we just take the lower bits of the key, and do no attempt to solve
+ * collisions. Use a proper hash table when we have dozens of drivers. 
+ */
+static uint32_t debug_mask_table[DEBUG_MASK_TABLE_SIZE];
+
+
+void debug_mask_set(uint32_t uuid, uint32_t mask) 
+{
+   unsigned hash = uuid & (DEBUG_MASK_TABLE_SIZE - 1);
+   debug_mask_table[hash] = mask;
+}
+
+
+uint32_t debug_mask_get(uint32_t uuid)
+{
+   unsigned hash = uuid & (DEBUG_MASK_TABLE_SIZE - 1);
+   return debug_mask_table[hash];
+}
+
+
+void debug_mask_vprintf(uint32_t uuid, uint32_t what, const char *format, va_list ap)
+{
+   uint32_t mask = debug_mask_get(uuid);
+   if(mask & what)
+      debug_vprintf(format, ap);
+}