48481 involves a huge function involving calls to functions taking class
arguments. Detailed memory statistics pointed to three primary sources
of garbage:
1) BASELINKs from lookup of constructors for considering a user-defined
conversion sequence. We can just avoid creating these in the first
place, since we always find constructors in the type itself.
2) VEC(tree)s created in build_user_type_conversion_1 and then not
freed. So we release the vec if we don't actually end up needing it.
3) OVERLOADs from argument-dependent lookup. We allocate some of these
whenever we do argument-dependent lookup, which is pretty wasteful in
the common case that unqualified lookup finds all the interesting
functions, because we end up looking at every function twice -- once
from unqualified lookup, once from argument-dependent. We used to try
to avoid this in the common case, but stopped to get 2-phase name lookup
right. It seems to me that we could still do the optimization in the
non-template case, but that will be a later patch.
This patch marks the OVERLOADs as coming from arg-dependent lookup so
that we can free them again once we're done with the call.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit fe4fd71bfe5c968261c332c2792047dcfe36da3c
Author: Jason Merrill <ja...@redhat.com>
Date: Wed Apr 6 15:09:09 2011 -0400
PR c++/48481
* call.c (build_user_type_conversion_1): Use lookup_fnfields_slot.
Release unused vector.
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index f283bd1..096fbbc 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -3249,7 +3249,9 @@ build_user_type_conversion_1 (tree totype, tree expr, int
flags)
|| !DERIVED_FROM_P (totype, fromtype));
if (MAYBE_CLASS_TYPE_P (totype))
- ctors = lookup_fnfields (totype, complete_ctor_identifier, 0);
+ /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
+ creating a garbage BASELINK; constructors can't be inherited. */
+ ctors = lookup_fnfields_slot (totype, complete_ctor_identifier);
if (MAYBE_CLASS_TYPE_P (fromtype))
{
@@ -3281,7 +3283,6 @@ build_user_type_conversion_1 (tree totype, tree expr, int
flags)
if (ctors)
{
int ctorflags = flags;
- ctors = BASELINK_FUNCTIONS (ctors);
first_arg = build_int_cst (build_pointer_type (totype), 0);
@@ -3389,7 +3390,11 @@ build_user_type_conversion_1 (tree totype, tree expr,
int flags)
candidates = splice_viable (candidates, pedantic, &any_viable_p);
if (!any_viable_p)
- return NULL;
+ {
+ if (args)
+ release_tree_vector (args);
+ return NULL;
+ }
cand = tourney (candidates);
if (cand == 0)
commit 88c1fe424f19e08870fb6d2b5e54eee9d354095f
Author: Jason Merrill <ja...@redhat.com>
Date: Thu Apr 7 11:48:09 2011 -0400
PR c++/48481
* cp-tree.h (OVL_ARG_DEPENDENT): New.
* name-lookup.c (add_function): Set it.
* semantics.c (finish_call_expr): Free OVERLOADs if it's set.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index ea251a8..885b31c 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -317,6 +317,9 @@ typedef struct ptrmem_cst * ptrmem_cst_t;
This is not to confuse with being used somewhere, which
is not important for this node. */
#define OVL_USED(NODE) TREE_USED (NODE)
+/* If set, this OVERLOAD was created for argument-dependent lookup
+ and can be freed afterward. */
+#define OVL_ARG_DEPENDENT(NODE) TREE_LANG_FLAG_0 (OVERLOAD_CHECK (NODE))
struct GTY(()) tree_overload {
struct tree_common common;
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 18e3441..696a8f5 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -4725,7 +4725,11 @@ add_function (struct arg_lookup *k, tree fn)
else if (fn == k->functions)
;
else
- k->functions = build_overload (fn, k->functions);
+ {
+ k->functions = build_overload (fn, k->functions);
+ if (TREE_CODE (k->functions) == OVERLOAD)
+ OVL_ARG_DEPENDENT (k->functions) = true;
+ }
return false;
}
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 30175af..2184a53 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2160,6 +2160,25 @@ finish_call_expr (tree fn, VEC(tree,gc) **args, bool
disallow_virtual,
result = convert_from_reference (result);
}
+ if (koenig_p)
+ {
+ /* Free garbage OVERLOADs from arg-dependent lookup. */
+ tree next = NULL_TREE;
+ for (fn = orig_fn;
+ fn && TREE_CODE (fn) == OVERLOAD && OVL_ARG_DEPENDENT (fn);
+ fn = next)
+ {
+ if (processing_template_decl)
+ /* In a template, we'll re-use them at instantiation time. */
+ OVL_ARG_DEPENDENT (fn) = false;
+ else
+ {
+ next = OVL_CHAIN (fn);
+ ggc_free (fn);
+ }
+ }
+ }
+
return result;
}
commit e57283fb9a55c107cc924ed9c3afa1866adcbe5e
Author: Jason Merrill <ja...@redhat.com>
Date: Thu Apr 7 12:05:45 2011 -0400
PR c++/48481
* tree.c (build_overload): Allow an unwrapped FUNCTION_DECL
at the end of the chain.
* pt.c (dependent_template_p): Use OVL_CURRENT/NEXT.
(iterative_hash_template_arg): Likewise.
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 696a8f5..2136df6 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -5139,8 +5139,8 @@ arg_assoc (struct arg_lookup *k, tree n)
}
else if (TREE_CODE (n) == OVERLOAD)
{
- for (; n; n = OVL_CHAIN (n))
- if (arg_assoc_type (k, TREE_TYPE (OVL_FUNCTION (n))))
+ for (; n; n = OVL_NEXT (n))
+ if (arg_assoc_type (k, TREE_TYPE (OVL_CURRENT (n))))
return true;
}
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4edd404..86274e9 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -1516,8 +1516,8 @@ iterative_hash_template_arg (tree arg, hashval_t val)
return val;
case OVERLOAD:
- for (; arg; arg = OVL_CHAIN (arg))
- val = iterative_hash_template_arg (OVL_FUNCTION (arg), val);
+ for (; arg; arg = OVL_NEXT (arg))
+ val = iterative_hash_template_arg (OVL_CURRENT (arg), val);
return val;
case CONSTRUCTOR:
@@ -18591,9 +18591,9 @@ dependent_template_p (tree tmpl)
{
while (tmpl)
{
- if (dependent_template_p (OVL_FUNCTION (tmpl)))
+ if (dependent_template_p (OVL_CURRENT (tmpl)))
return true;
- tmpl = OVL_CHAIN (tmpl);
+ tmpl = OVL_NEXT (tmpl);
}
return false;
}
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 014986d..3594ae4 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1461,8 +1461,6 @@ build_overload (tree decl, tree chain)
{
if (! chain && TREE_CODE (decl) != TEMPLATE_DECL)
return decl;
- if (chain && TREE_CODE (chain) != OVERLOAD)
- chain = ovl_cons (chain, NULL_TREE);
return ovl_cons (decl, chain);
}
