From: Jason Merrill <jason@redhat.com>
To: gcc-patches List <gcc-patches@gcc.gnu.org>
Subject: RFA (hash-map): PATCH to support GTY((cache)) with hash_map
Date: Fri, 15 Sep 2017 21:45:00 -0000 [thread overview]
Message-ID: <CADzB+2n4mtiYNocfZYCE7xKwEf6aZW+QX9FdR05zf2a-9Qi4TQ@mail.gmail.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1093 bytes --]
The hash_map interface is a lot more convenient than that of
hash_table for cases where it makes sense, but there hasn't been a way
to get the ggc_cache_remove behavior with a hash_map. In other words,
not marking elements during the initial ggc marking phase, but maybe
marking them during the clear_caches phase based on keep_cache_entry.
This patch implements that by:
Adding a ggc_maybe_mx member function to ggc_remove, and overriding
that instead of ggc_mx in ggc_cache_remove.
Calling H::ggc_maybe_mx instead of H::ggc_mx in gt_ggc_mx (hash_table *).
Calling H::ggc_mx in gt_cleare_caches (hash_table *) rather than
relying on an extern declaration of a plain function that cannot be
declared for hash_map::hash_entry.
Adding ggc_maybe_mx and keep_cache_entry to hash_map::hash_entry.
Adding gt_cleare_cache for hash_map.
Adding a boolean constant to the hash-map traits indicating whether we
want the cache behavior above.
I then define a typedef tree_cache_map to use this functionality, and
use it in a few places in the C++ front end.
Tested x86_64-pc-linux-gnu, OK for trunk?
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commit 29a77538437442915ecb85516e3710c918d0e8ac
Author: Jason Merrill <jason@redhat.com>
Date: Wed Sep 13 14:33:33 2017 -0400
Support GTY((cache)) on hash_map.
gcc/
* hash-traits.h (ggc_remove): Add ggc_maybe_mx member function.
(ggc_cache_remove): Override it instead of ggc_mx.
* hash-table.h (gt_ggc_mx): Call it instead of ggc_mx.
(gt_cleare_cache): Call ggc_mx instead of gt_ggc_mx.
* hash-map-traits.h (simple_hashmap_traits): Add maybe_mx member.
(simple_cache_map_traits): Override maybe_mx.
* hash-map.h (hash_entry): Add ggc_maybe_mx and keep_cache_entry.
(hash_map): Friend gt_cleare_cache.
(gt_cleare_cache): New.
* tree.h (tree_cache_traits): New hash_map traits class.
(tree_cache_map): New typedef.
gcc/cp/
* decl.c (decomp_type_table): Use tree_cache_map.
* init.c (nsdmi_inst): Likewise.
* pt.c (defarg_ints): Likewise.
* cp-objcp-common.c (cp_get_debug_type): Likewise.
diff --git a/gcc/cp/cp-objcp-common.c b/gcc/cp/cp-objcp-common.c
index 183e7f7bf57..27f0b985378 100644
--- a/gcc/cp/cp-objcp-common.c
+++ b/gcc/cp/cp-objcp-common.c
@@ -131,19 +131,7 @@ cxx_types_compatible_p (tree x, tree y)
return same_type_ignoring_top_level_qualifiers_p (x, y);
}
-struct debug_type_hasher : ggc_cache_ptr_hash<tree_map>
-{
- static hashval_t hash (tree_map *m) { return tree_map_hash (m); }
- static bool equal (tree_map *a, tree_map *b) { return tree_map_eq (a, b); }
-
- static int
- keep_cache_entry (tree_map *&e)
- {
- return ggc_marked_p (e->base.from);
- }
-};
-
-static GTY((cache)) hash_table<debug_type_hasher> *debug_type_hash;
+static GTY((cache)) tree_cache_map *debug_type_map;
/* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
keep TYPE. */
@@ -151,38 +139,29 @@ static GTY((cache)) hash_table<debug_type_hasher> *debug_type_hash;
tree
cp_get_debug_type (const_tree type)
{
+ tree dtype = NULL_TREE;
+
if (TYPE_PTRMEMFUNC_P (type) && !typedef_variant_p (type))
+ dtype = build_offset_type (TYPE_PTRMEMFUNC_OBJECT_TYPE (type),
+ TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (type)));
+
+ /* We cannot simply return the debug type here because the function uses
+ the type canonicalization hashtable, which is GC-ed, so its behavior
+ depends on the actual collection points. Since we are building these
+ types on the fly for the debug info only, they would not be attached
+ to any GC root and always be swept, so we would make the contents of
+ the debug info depend on the collection points. */
+ if (dtype)
{
- if (debug_type_hash == NULL)
- debug_type_hash = hash_table<debug_type_hasher>::create_ggc (512);
-
- /* We cannot simply use build_offset_type here because the function uses
- the type canonicalization hashtable, which is GC-ed, so its behavior
- depends on the actual collection points. Since we are building these
- types on the fly for the debug info only, they would not be attached
- to any GC root and always be swept, so we would make the contents of
- the debug info depend on the collection points. */
- struct tree_map in, *h;
-
- in.base.from = CONST_CAST_TREE (type);
- in.hash = htab_hash_pointer (type);
- h = debug_type_hash->find_with_hash (&in, in.hash);
- if (h)
- return h->to;
-
- tree t = build_offset_type (TYPE_PTRMEMFUNC_OBJECT_TYPE (type),
- TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (type)));
-
- h = ggc_alloc<tree_map> ();
- h->base.from = CONST_CAST_TREE (type);
- h->hash = htab_hash_pointer (type);
- h->to = t;
- *debug_type_hash->find_slot_with_hash (h, h->hash, INSERT) = h;
-
- return t;
+ tree ktype = CONST_CAST_TREE (type);
+ if (debug_type_map == NULL)
+ debug_type_map = tree_cache_map::create_ggc (512);
+ else if (tree *slot = debug_type_map->get (ktype))
+ return *slot;
+ debug_type_map->put (ktype, dtype);
}
- return NULL_TREE;
+ return dtype;
}
/* Return -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index f4d6f802cbe..06a4a7d22cc 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5117,7 +5117,6 @@ extern GTY(()) vec<tree, va_gc> *static_decls;
/* An array of vtable-needing types that have no key function, or have
an emitted key function. */
extern GTY(()) vec<tree, va_gc> *keyed_classes;
-
\f
/* Here's where we control how name mangling takes place. */
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 6101bdf2bc8..bfb0ebe9642 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7303,12 +7303,13 @@ get_tuple_decomp_init (tree decl, unsigned i)
/* It's impossible to recover the decltype of a tuple decomposition variable
based on the actual type of the variable, so store it in a hash table. */
-static GTY(()) hash_map<tree,tree> *decomp_type_table;
+
+static GTY((cache)) tree_cache_map *decomp_type_table;
static void
store_decomp_type (tree v, tree t)
{
if (!decomp_type_table)
- decomp_type_table = hash_map<tree,tree>::create_ggc (13);
+ decomp_type_table = tree_cache_map::create_ggc (13);
decomp_type_table->put (v, t);
}
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index b01d662fef2..d6241d29379 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -535,7 +535,7 @@ perform_target_ctor (tree init)
/* Return the non-static data initializer for FIELD_DECL MEMBER. */
-static GTY(()) hash_map<tree, tree> *nsdmi_inst;
+static GTY((cache)) tree_cache_map *nsdmi_inst;
tree
get_nsdmi (tree member, bool in_ctor, tsubst_flags_t complain)
@@ -590,7 +590,7 @@ get_nsdmi (tree member, bool in_ctor, tsubst_flags_t complain)
if (init != error_mark_node)
{
if (!nsdmi_inst)
- nsdmi_inst = hash_map<tree,tree>::create_ggc (37);
+ nsdmi_inst = tree_cache_map::create_ggc (37);
nsdmi_inst->put (member, init);
}
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index ec7bbc890c6..aa158dc939d 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -12008,7 +12008,7 @@ tsubst_aggr_type (tree t,
}
}
-static GTY(()) hash_map<tree, tree> *defarg_inst;
+static GTY((cache)) tree_cache_map *defarg_inst;
/* Substitute into the default argument ARG (a default argument for
FN), which has the indicated TYPE. */
@@ -12095,7 +12095,7 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
if (arg != error_mark_node && !cp_unevaluated_operand)
{
if (!defarg_inst)
- defarg_inst = hash_map<tree,tree>::create_ggc (37);
+ defarg_inst = tree_cache_map::create_ggc (37);
defarg_inst->put (parm, arg);
}
diff --git a/gcc/hash-map-traits.h b/gcc/hash-map-traits.h
index 2b5fddf2d09..a92f0cb00f4 100644
--- a/gcc/hash-map-traits.h
+++ b/gcc/hash-map-traits.h
@@ -32,6 +32,7 @@ template <typename H, typename Value>
struct simple_hashmap_traits
{
typedef typename H::value_type key_type;
+ static const bool maybe_mx = true;
static inline hashval_t hash (const key_type &);
static inline bool equal_keys (const key_type &, const key_type &);
template <typename T> static inline void remove (T &);
@@ -97,6 +98,12 @@ simple_hashmap_traits <H, Value>::mark_deleted (T &entry)
H::mark_deleted (entry.m_key);
}
+template <typename H, typename Value>
+struct simple_cache_map_traits: public simple_hashmap_traits<H,Value>
+{
+ static const bool maybe_mx = false;
+};
+
/* Implement traits for a hash_map with values of type Value for cases
in which the key cannot represent empty and deleted slots. Instead
record empty and deleted entries in Value. Derived classes must
diff --git a/gcc/hash-map.h b/gcc/hash-map.h
index 73f1c5427a0..6b8365a9d0a 100644
--- a/gcc/hash-map.h
+++ b/gcc/hash-map.h
@@ -62,6 +62,12 @@ class GTY((user)) hash_map
gt_ggc_mx (e.m_value);
}
+ static void ggc_maybe_mx (hash_entry &e)
+ {
+ if (Traits::maybe_mx)
+ ggc_mx (e);
+ }
+
static void pch_nx (hash_entry &e)
{
gt_pch_nx (e.m_key);
@@ -74,6 +80,11 @@ class GTY((user)) hash_map
pch_nx_helper (e.m_value, op, c);
}
+ static int keep_cache_entry (hash_entry &e)
+ {
+ return ggc_marked_p (e.m_key);
+ }
+
private:
template<typename T>
static void
@@ -237,7 +248,8 @@ private:
template<typename T, typename U, typename V> friend void gt_ggc_mx (hash_map<T, U, V> *);
template<typename T, typename U, typename V> friend void gt_pch_nx (hash_map<T, U, V> *);
- template<typename T, typename U, typename V> friend void gt_pch_nx (hash_map<T, U, V> *, gt_pointer_operator, void *);
+ template<typename T, typename U, typename V> friend void gt_pch_nx (hash_map<T, U, V> *, gt_pointer_operator, void *);
+ template<typename T, typename U, typename V> friend void gt_cleare_cache (hash_map<T, U, V> *);
hash_table<hash_entry> m_table;
};
@@ -260,6 +272,13 @@ gt_pch_nx (hash_map<K, V, H> *h)
template<typename K, typename V, typename H>
static inline void
+gt_cleare_cache (hash_map<K, V, H> *h)
+{
+ gt_cleare_cache (&h->m_table);
+}
+
+template<typename K, typename V, typename H>
+static inline void
gt_pch_nx (hash_map<K, V, H> *h, gt_pointer_operator op, void *cookie)
{
op (&h->m_table.m_entries, cookie);
diff --git a/gcc/hash-table.h b/gcc/hash-table.h
index 64d3157953c..b86a1d1b278 100644
--- a/gcc/hash-table.h
+++ b/gcc/hash-table.h
@@ -1044,7 +1044,9 @@ gt_ggc_mx (hash_table<E> *h)
|| table::is_deleted (h->m_entries[i]))
continue;
- E::ggc_mx (h->m_entries[i]);
+ /* Use ggc_maxbe_mx so we don't mark right away for cache tables; we'll
+ mark in gt_cleare_cache if appropriate. */
+ E::ggc_maybe_mx (h->m_entries[i]);
}
}
@@ -1094,7 +1096,6 @@ template<typename H>
inline void
gt_cleare_cache (hash_table<H> *h)
{
- extern void gt_ggc_mx (typename H::value_type &t);
typedef hash_table<H> table;
if (!h)
return;
@@ -1106,7 +1107,7 @@ gt_cleare_cache (hash_table<H> *h)
if (res == 0)
h->clear_slot (&*iter);
else if (res != -1)
- gt_ggc_mx (*iter);
+ H::ggc_mx (*iter);
}
}
diff --git a/gcc/hash-traits.h b/gcc/hash-traits.h
index a5c4f103474..6a613c45811 100644
--- a/gcc/hash-traits.h
+++ b/gcc/hash-traits.h
@@ -235,6 +235,13 @@ struct ggc_remove
gt_ggc_mx (p);
}
+ /* Overridden in ggc_cache_remove. */
+ static void
+ ggc_maybe_mx (T &p)
+ {
+ ggc_mx (p);
+ }
+
static void
pch_nx (T &p)
{
@@ -256,7 +263,7 @@ template<typename T>
struct ggc_cache_remove : ggc_remove<T>
{
/* Entries are weakly held because this is for caches. */
- static void ggc_mx (T &) {}
+ static void ggc_maybe_mx (T &) {}
static int
keep_cache_entry (T &e)
diff --git a/gcc/tree.h b/gcc/tree.h
index caa4a69977d..6845953c09c 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4873,6 +4873,13 @@ struct tree_decl_map_cache_hasher : ggc_cache_ptr_hash<tree_decl_map>
#define tree_vec_map_hash tree_decl_map_hash
#define tree_vec_map_marked_p tree_map_base_marked_p
+/* A hash_map of two trees for use with GTY((cache)). Garbage collection for
+ such a map will not mark keys, and will mark values if the key is already
+ marked. */
+struct tree_cache_traits
+ : simple_cache_map_traits<default_hash_traits<tree>, tree> { };
+typedef hash_map<tree,tree,tree_cache_traits> tree_cache_map;
+
/* Initialize the abstract argument list iterator object ITER with the
arguments from CALL_EXPR node EXP. */
static inline void
next reply other threads:[~2017-09-15 21:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-15 21:45 Jason Merrill [this message]
2017-11-14 12:55 ` Richard Biener
2017-11-26 0:23 ` Markus Trippelsdorf
2017-11-26 10:14 ` [PATCH] Fix UB in hash-map.h Markus Trippelsdorf
2017-11-27 13:01 ` Richard Biener
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