It turned out that for tree -> tree mapping we don't need the hash
table at all; pointer map is much more convenient. So this patch
weeds out the hash table out of ubsan and introduces pointer map
instead. Quite a lot of code could go away--no need to set the
alloc pools up etc.
Regtested, ran bootstrap-ubsan on x86_64-linux. Applying to the
ubsan branch.
2013-08-27 Marek Polacek <pola...@redhat.com>
* ubsan.c: Use pointer map instead of hash table.
--- gcc/ubsan.c.mp 2013-08-27 12:31:04.136213922 +0200
+++ gcc/ubsan.c 2013-08-27 12:31:10.361236456 +0200
@@ -22,109 +22,42 @@ along with GCC; see the file COPYING3.
#include "system.h"
#include "coretypes.h"
#include "tree.h"
-#include "alloc-pool.h"
#include "cgraph.h"
#include "gimple.h"
-#include "hash-table.h"
+#include "pointer-set.h"
#include "output.h"
#include "toplev.h"
#include "ubsan.h"
#include "c-family/c-common.h"
-/* This type represents an entry in the hash table; this hash table
- maps from a TYPE to a ubsan type descriptor VAR_DECL for that type. */
-struct ubsan_typedesc
-{
- /* This represents the type of a variable. */
- tree type;
-
- /* This is the VAR_DECL of the type. */
- tree decl;
-};
-
-static alloc_pool ubsan_typedesc_alloc_pool;
-
-/* Hash table for type descriptors. */
-struct ubsan_typedesc_hasher
- : typed_noop_remove <ubsan_typedesc>
-{
- typedef ubsan_typedesc value_type;
- typedef ubsan_typedesc compare_type;
-
- static inline hashval_t hash (const value_type *);
- static inline bool equal (const value_type *, const compare_type *);
-};
-
-/* Hash a memory reference. */
-
-inline hashval_t
-ubsan_typedesc_hasher::hash (const ubsan_typedesc *data)
-{
- return iterative_hash_object (TYPE_UID (data->type), 0);
-}
-
-/* Compare two data types. */
-
-inline bool
-ubsan_typedesc_hasher::equal (const ubsan_typedesc *d1,
- const ubsan_typedesc *d2)
-{
- /* Here, the types should have identical __typekind,
- __typeinfo and __typename. */
- return d1->type == d2->type;
-}
-
-static hash_table <ubsan_typedesc_hasher> ubsan_typedesc_ht;
+/* Map a TYPE to an ubsan type descriptor VAR_DECL for that type. */
+static pointer_map_t *typedesc_map;
-/* Initializes an instance of ubsan_typedesc. */
+/* Insert DECL as the VAR_DECL for TYPE in the TYPEDESC_MAP. */
static void
-ubsan_typedesc_init (ubsan_typedesc *data, tree type, tree decl)
+insert_decl_for_type (tree decl, tree type)
{
- data->type = type;
- data->decl = decl;
+ void **slot = pointer_map_insert (typedesc_map, type);
+ gcc_assert (*slot == NULL);
+ *slot = decl;
}
-/* This creates the alloc pool used to store the instances of
- ubsan_typedesc that are stored in the hash table ubsan_typedesc_ht. */
+/* Find the VAR_DECL for TYPE in TYPEDESC_MAP. If TYPE does not
+ exist in the map, return NULL_TREE, otherwise, return the VAR_DECL
+ we found. */
-static alloc_pool
-ubsan_typedesc_get_alloc_pool ()
-{
- if (ubsan_typedesc_alloc_pool == NULL)
- ubsan_typedesc_alloc_pool = create_alloc_pool ("ubsan_typedesc",
- sizeof (ubsan_typedesc),
- 10);
- return ubsan_typedesc_alloc_pool;
-}
-
-/* Returns a reference to the hash table containing data type.
- This function ensures that the hash table is created. */
-
-static hash_table <ubsan_typedesc_hasher> &
-get_typedesc_hash_table ()
-{
- if (!ubsan_typedesc_ht.is_created ())
- ubsan_typedesc_ht.create (10);
-
- return ubsan_typedesc_ht;
-}
-
-/* Allocates memory for an instance of ubsan_typedesc into the memory
- pool returned by ubsan_typedesc_get_alloc_pool and initialize it.
- TYPE describes a particular type, DECL is its VAR_DECL. */
-
-static ubsan_typedesc *
-ubsan_typedesc_new (tree type, tree decl)
+static tree
+lookup_decl_for_type (tree type)
{
- ubsan_typedesc *desc =
- (ubsan_typedesc *) pool_alloc (ubsan_typedesc_get_alloc_pool ());
-
- ubsan_typedesc_init (desc, type, decl);
- return desc;
+ /* If the pointer map is not initialized yet, create it now. */
+ if (typedesc_map == NULL)
+ typedesc_map = pointer_map_create ();
+ void **slot = pointer_map_contains (typedesc_map, type);
+ return slot ? (tree) *slot : NULL_TREE;
}
-/* Helper routine, which encodes a value in the uptr type.
+/* Helper routine, which encodes a value in the pointer_sized_int_node.
Arguments with precision <= POINTER_SIZE are passed directly,
the rest is passed by reference. T is a value we are to encode. */
@@ -281,24 +214,19 @@ get_ubsan_type_info_for_type (tree type)
}
/* Helper routine that returns ADDR_EXPR of a VAR_DECL of a type
- descriptor. It first looks into the hash table; if not found,
- create the VAR_DECL, put it into the hash table and return the
+ descriptor. It first looks into the pointer map; if not found,
+ create the VAR_DECL, put it into the pointer map and return the
ADDR_EXPR of it. TYPE describes a particular type. */
tree
ubsan_type_descriptor (tree type)
{
- hash_table <ubsan_typedesc_hasher> ht = get_typedesc_hash_table ();
- ubsan_typedesc d;
-
/* See through any typedefs. */
type = TYPE_MAIN_VARIANT (type);
- ubsan_typedesc_init (&d, type, NULL);
- ubsan_typedesc **slot = ht.find_slot (&d, INSERT);
- if (*slot != NULL)
- /* We have the VAR_DECL in the table. Return it. */
- return (*slot)->decl;
+ tree decl = lookup_decl_for_type (type);
+ if (decl != NULL_TREE)
+ return decl;
tree dtype = ubsan_type_descriptor_type ();
const char *tname;
@@ -326,7 +254,7 @@ ubsan_type_descriptor (tree type)
char tmp_name[32];
static unsigned int type_var_id_num;
ASM_GENERATE_INTERNAL_LABEL (tmp_name, "Lubsan_type", type_var_id_num++);
- tree decl = build_decl (UNKNOWN_LOCATION, VAR_DECL, get_identifier
(tmp_name),
+ decl = build_decl (UNKNOWN_LOCATION, VAR_DECL, get_identifier (tmp_name),
dtype);
TREE_STATIC (decl) = 1;
TREE_PUBLIC (decl) = 0;
@@ -350,9 +278,9 @@ ubsan_type_descriptor (tree type)
DECL_INITIAL (decl) = ctor;
rest_of_decl_compilation (decl, 1, 0);
- /* Save the address of the VAR_DECL into the hash table. */
+ /* Save the address of the VAR_DECL into the pointer map. */
decl = build_fold_addr_expr (decl);
- *slot = ubsan_typedesc_new (type, decl);
+ insert_decl_for_type (decl, type);
return decl;
}
Marek
