[RFA,(tree)] c++: lambda in template default argument [PR103186]
Commit Message
The problem with this testcase was that since my patch for PR97900 we
weren't preserving DECL_UID identity for parameters of instantiations of
templated functions, so using those parameters as the keys for the
defarg_inst map broke. I think this was always fragile given the
possibility of redeclarations, so instead of reverting that change let's
switch to keying off the function.
Memory use compiling stdc++.h is not noticeably different.
Tested x86_64-pc-linux-gnu. Is the tree.{h,cc} change, just moving the class
definition from one to the other, OK for trunk?
PR c++/103186
gcc/ChangeLog:
* tree.h (struct tree_vec_map_cache_hasher): Move from...
* tree.cc (struct tree_vec_map_cache_hasher): ...here.
gcc/cp/ChangeLog:
* pt.cc (defarg_inst): Use tree_vec_map_cache_hasher.
(defarg_inst_for): New.
(tsubst_default_argument): Adjust.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/lambda/lambda-defarg10.C: New test.
---
gcc/tree.h | 17 ++++++++
gcc/cp/pt.cc | 43 +++++++++++++++----
.../g++.dg/cpp0x/lambda/lambda-defarg10.C | 21 +++++++++
gcc/tree.cc | 17 --------
4 files changed, 72 insertions(+), 26 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
base-commit: 9bf217920457f2e2d46b601f24721780a20a031b
prerequisite-patch-id: c7ab4056fcbd782232c8dc091597602ecd4a7a48
Comments
Ping.
On 1/26/22 18:16, Jason Merrill wrote:
> The problem with this testcase was that since my patch for PR97900 we
> weren't preserving DECL_UID identity for parameters of instantiations of
> templated functions, so using those parameters as the keys for the
> defarg_inst map broke. I think this was always fragile given the
> possibility of redeclarations, so instead of reverting that change let's
> switch to keying off the function.
>
> Memory use compiling stdc++.h is not noticeably different.
>
> Tested x86_64-pc-linux-gnu. Is the tree.{h,cc} change, just moving the class
> definition from one to the other, OK for trunk?
>
> PR c++/103186
>
> gcc/ChangeLog:
>
> * tree.h (struct tree_vec_map_cache_hasher): Move from...
> * tree.cc (struct tree_vec_map_cache_hasher): ...here.
>
> gcc/cp/ChangeLog:
>
> * pt.cc (defarg_inst): Use tree_vec_map_cache_hasher.
> (defarg_inst_for): New.
> (tsubst_default_argument): Adjust.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/lambda/lambda-defarg10.C: New test.
> ---
> gcc/tree.h | 17 ++++++++
> gcc/cp/pt.cc | 43 +++++++++++++++----
> .../g++.dg/cpp0x/lambda/lambda-defarg10.C | 21 +++++++++
> gcc/tree.cc | 17 --------
> 4 files changed, 72 insertions(+), 26 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
>
> diff --git a/gcc/tree.h b/gcc/tree.h
> index 30bc53c2996..c5617fbcc61 100644
> --- a/gcc/tree.h
> +++ b/gcc/tree.h
> @@ -5559,6 +5559,23 @@ 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
>
> +struct tree_vec_map_cache_hasher : ggc_cache_ptr_hash<tree_vec_map>
> +{
> + static hashval_t hash (tree_vec_map *m) { return DECL_UID (m->base.from); }
> +
> + static bool
> + equal (tree_vec_map *a, tree_vec_map *b)
> + {
> + return a->base.from == b->base.from;
> + }
> +
> + static int
> + keep_cache_entry (tree_vec_map *&m)
> + {
> + return ggc_marked_p (m->base.from);
> + }
> +};
> +
> /* Hasher for tree decls. Pointer equality is enough here, but the DECL_UID
> is a better hash than the pointer value and gives a predictable traversal
> order. Additionally it can be used across PCH save/restore. */
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 6fbda676527..db99b988fc3 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -13666,7 +13666,36 @@ tsubst_aggr_type (tree t,
> }
> }
>
> -static GTY((cache)) decl_tree_cache_map *defarg_inst;
> +/* Map from a FUNCTION_DECL to a vec of default argument instantiations. */
> +
> +static GTY((cache)) hash_table<tree_vec_map_cache_hasher> *defarg_inst;
> +
> +/* Return a reference to the slot for the defarg inst of PARM. */
> +
> +tree &
> +defarg_inst_for (tree parm)
> +{
> + if (!defarg_inst)
> + defarg_inst = hash_table<tree_vec_map_cache_hasher>::create_ggc (13);
> + tree fn = DECL_CONTEXT (parm);
> + tree_vec_map in = { fn, nullptr };
> + tree_vec_map **slot
> + = defarg_inst->find_slot_with_hash (&in, DECL_UID (fn), INSERT);
> + if (!*slot)
> + {
> + *slot = ggc_alloc<tree_vec_map> ();
> + **slot = in;
> + }
> +
> + /* Index in reverse order to avoid allocating space for initial parameters
> + that don't have default arguments. */
> + unsigned ridx = list_length (parm);
> +
> + vec<tree,va_gc> *&defs = (*slot)->to;
> + if (vec_safe_length (defs) < ridx)
> + vec_safe_grow_cleared (defs, ridx);
> + return (*defs)[ridx - 1];
> +}
>
> /* Substitute into the default argument ARG (a default argument for
> FN), which has the indicated TYPE. */
> @@ -13696,9 +13725,9 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
>
> gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, parmtype));
>
> - tree *slot;
> - if (defarg_inst && (slot = defarg_inst->get (parm)))
> - return *slot;
> + tree &inst = defarg_inst_for (parm);
> + if (inst)
> + return inst;
>
> /* This default argument came from a template. Instantiate the
> default argument here, not in tsubst. In the case of
> @@ -13743,11 +13772,7 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
> pop_from_top_level ();
>
> if (arg != error_mark_node && !cp_unevaluated_operand)
> - {
> - if (!defarg_inst)
> - defarg_inst = decl_tree_cache_map::create_ggc (37);
> - defarg_inst->put (parm, arg);
> - }
> + inst = arg;
>
> return arg;
> }
> diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
> new file mode 100644
> index 00000000000..e08eb4f5e56
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
> @@ -0,0 +1,21 @@
> +// PR c++/103186
> +// { dg-do compile { target c++11 } }
> +
> +struct f
> +{
> + template<class T1>
> + f(const T1&){}
> +};
> +
> +
> +template<typename T> class A {
> +public:
> + void foo(A<T> a, const f& fn = [](){}) { }
> + void bar(A<T> a) { foo(a); }
> +};
> +int main() {
> + A<int> a;
> + a.foo(a);
> + a.bar(a);
> + return 0;
> +}
> diff --git a/gcc/tree.cc b/gcc/tree.cc
> index c4b36619e6a..6bd3b14c93c 100644
> --- a/gcc/tree.cc
> +++ b/gcc/tree.cc
> @@ -242,23 +242,6 @@ static GTY ((cache))
> static GTY ((cache))
> hash_table<tree_decl_map_cache_hasher> *value_expr_for_decl;
>
> -struct tree_vec_map_cache_hasher : ggc_cache_ptr_hash<tree_vec_map>
> -{
> - static hashval_t hash (tree_vec_map *m) { return DECL_UID (m->base.from); }
> -
> - static bool
> - equal (tree_vec_map *a, tree_vec_map *b)
> - {
> - return a->base.from == b->base.from;
> - }
> -
> - static int
> - keep_cache_entry (tree_vec_map *&m)
> - {
> - return ggc_marked_p (m->base.from);
> - }
> -};
> -
> static GTY ((cache))
> hash_table<tree_vec_map_cache_hasher> *debug_args_for_decl;
>
>
> base-commit: 9bf217920457f2e2d46b601f24721780a20a031b
> prerequisite-patch-id: c7ab4056fcbd782232c8dc091597602ecd4a7a48
On Wed, Jan 26, 2022 at 06:16:34PM -0500, Jason Merrill via Gcc-patches wrote:
> The problem with this testcase was that since my patch for PR97900 we
> weren't preserving DECL_UID identity for parameters of instantiations of
> templated functions, so using those parameters as the keys for the
> defarg_inst map broke. I think this was always fragile given the
> possibility of redeclarations, so instead of reverting that change let's
> switch to keying off the function.
>
> Memory use compiling stdc++.h is not noticeably different.
>
> Tested x86_64-pc-linux-gnu. Is the tree.{h,cc} change, just moving the class
> definition from one to the other, OK for trunk?
Ok.
> PR c++/103186
>
> gcc/ChangeLog:
>
> * tree.h (struct tree_vec_map_cache_hasher): Move from...
> * tree.cc (struct tree_vec_map_cache_hasher): ...here.
>
> gcc/cp/ChangeLog:
>
> * pt.cc (defarg_inst): Use tree_vec_map_cache_hasher.
> (defarg_inst_for): New.
> (tsubst_default_argument): Adjust.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/lambda/lambda-defarg10.C: New test.
Jakub
On Mon, Jan 31, 2022 at 10:34 PM Jason Merrill via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Ping.
OK.
Richard.
> On 1/26/22 18:16, Jason Merrill wrote:
> > The problem with this testcase was that since my patch for PR97900 we
> > weren't preserving DECL_UID identity for parameters of instantiations of
> > templated functions, so using those parameters as the keys for the
> > defarg_inst map broke. I think this was always fragile given the
> > possibility of redeclarations, so instead of reverting that change let's
> > switch to keying off the function.
> >
> > Memory use compiling stdc++.h is not noticeably different.
> >
> > Tested x86_64-pc-linux-gnu. Is the tree.{h,cc} change, just moving the class
> > definition from one to the other, OK for trunk?
> >
> > PR c++/103186
> >
> > gcc/ChangeLog:
> >
> > * tree.h (struct tree_vec_map_cache_hasher): Move from...
> > * tree.cc (struct tree_vec_map_cache_hasher): ...here.
> >
> > gcc/cp/ChangeLog:
> >
> > * pt.cc (defarg_inst): Use tree_vec_map_cache_hasher.
> > (defarg_inst_for): New.
> > (tsubst_default_argument): Adjust.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/cpp0x/lambda/lambda-defarg10.C: New test.
> > ---
> > gcc/tree.h | 17 ++++++++
> > gcc/cp/pt.cc | 43 +++++++++++++++----
> > .../g++.dg/cpp0x/lambda/lambda-defarg10.C | 21 +++++++++
> > gcc/tree.cc | 17 --------
> > 4 files changed, 72 insertions(+), 26 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
> >
> > diff --git a/gcc/tree.h b/gcc/tree.h
> > index 30bc53c2996..c5617fbcc61 100644
> > --- a/gcc/tree.h
> > +++ b/gcc/tree.h
> > @@ -5559,6 +5559,23 @@ 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
> >
> > +struct tree_vec_map_cache_hasher : ggc_cache_ptr_hash<tree_vec_map>
> > +{
> > + static hashval_t hash (tree_vec_map *m) { return DECL_UID (m->base.from); }
> > +
> > + static bool
> > + equal (tree_vec_map *a, tree_vec_map *b)
> > + {
> > + return a->base.from == b->base.from;
> > + }
> > +
> > + static int
> > + keep_cache_entry (tree_vec_map *&m)
> > + {
> > + return ggc_marked_p (m->base.from);
> > + }
> > +};
> > +
> > /* Hasher for tree decls. Pointer equality is enough here, but the DECL_UID
> > is a better hash than the pointer value and gives a predictable traversal
> > order. Additionally it can be used across PCH save/restore. */
> > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> > index 6fbda676527..db99b988fc3 100644
> > --- a/gcc/cp/pt.cc
> > +++ b/gcc/cp/pt.cc
> > @@ -13666,7 +13666,36 @@ tsubst_aggr_type (tree t,
> > }
> > }
> >
> > -static GTY((cache)) decl_tree_cache_map *defarg_inst;
> > +/* Map from a FUNCTION_DECL to a vec of default argument instantiations. */
> > +
> > +static GTY((cache)) hash_table<tree_vec_map_cache_hasher> *defarg_inst;
> > +
> > +/* Return a reference to the slot for the defarg inst of PARM. */
> > +
> > +tree &
> > +defarg_inst_for (tree parm)
> > +{
> > + if (!defarg_inst)
> > + defarg_inst = hash_table<tree_vec_map_cache_hasher>::create_ggc (13);
> > + tree fn = DECL_CONTEXT (parm);
> > + tree_vec_map in = { fn, nullptr };
> > + tree_vec_map **slot
> > + = defarg_inst->find_slot_with_hash (&in, DECL_UID (fn), INSERT);
> > + if (!*slot)
> > + {
> > + *slot = ggc_alloc<tree_vec_map> ();
> > + **slot = in;
> > + }
> > +
> > + /* Index in reverse order to avoid allocating space for initial parameters
> > + that don't have default arguments. */
> > + unsigned ridx = list_length (parm);
> > +
> > + vec<tree,va_gc> *&defs = (*slot)->to;
> > + if (vec_safe_length (defs) < ridx)
> > + vec_safe_grow_cleared (defs, ridx);
> > + return (*defs)[ridx - 1];
> > +}
> >
> > /* Substitute into the default argument ARG (a default argument for
> > FN), which has the indicated TYPE. */
> > @@ -13696,9 +13725,9 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
> >
> > gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, parmtype));
> >
> > - tree *slot;
> > - if (defarg_inst && (slot = defarg_inst->get (parm)))
> > - return *slot;
> > + tree &inst = defarg_inst_for (parm);
> > + if (inst)
> > + return inst;
> >
> > /* This default argument came from a template. Instantiate the
> > default argument here, not in tsubst. In the case of
> > @@ -13743,11 +13772,7 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
> > pop_from_top_level ();
> >
> > if (arg != error_mark_node && !cp_unevaluated_operand)
> > - {
> > - if (!defarg_inst)
> > - defarg_inst = decl_tree_cache_map::create_ggc (37);
> > - defarg_inst->put (parm, arg);
> > - }
> > + inst = arg;
> >
> > return arg;
> > }
> > diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
> > new file mode 100644
> > index 00000000000..e08eb4f5e56
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg10.C
> > @@ -0,0 +1,21 @@
> > +// PR c++/103186
> > +// { dg-do compile { target c++11 } }
> > +
> > +struct f
> > +{
> > + template<class T1>
> > + f(const T1&){}
> > +};
> > +
> > +
> > +template<typename T> class A {
> > +public:
> > + void foo(A<T> a, const f& fn = [](){}) { }
> > + void bar(A<T> a) { foo(a); }
> > +};
> > +int main() {
> > + A<int> a;
> > + a.foo(a);
> > + a.bar(a);
> > + return 0;
> > +}
> > diff --git a/gcc/tree.cc b/gcc/tree.cc
> > index c4b36619e6a..6bd3b14c93c 100644
> > --- a/gcc/tree.cc
> > +++ b/gcc/tree.cc
> > @@ -242,23 +242,6 @@ static GTY ((cache))
> > static GTY ((cache))
> > hash_table<tree_decl_map_cache_hasher> *value_expr_for_decl;
> >
> > -struct tree_vec_map_cache_hasher : ggc_cache_ptr_hash<tree_vec_map>
> > -{
> > - static hashval_t hash (tree_vec_map *m) { return DECL_UID (m->base.from); }
> > -
> > - static bool
> > - equal (tree_vec_map *a, tree_vec_map *b)
> > - {
> > - return a->base.from == b->base.from;
> > - }
> > -
> > - static int
> > - keep_cache_entry (tree_vec_map *&m)
> > - {
> > - return ggc_marked_p (m->base.from);
> > - }
> > -};
> > -
> > static GTY ((cache))
> > hash_table<tree_vec_map_cache_hasher> *debug_args_for_decl;
> >
> >
> > base-commit: 9bf217920457f2e2d46b601f24721780a20a031b
> > prerequisite-patch-id: c7ab4056fcbd782232c8dc091597602ecd4a7a48
>
@@ -5559,6 +5559,23 @@ 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
+struct tree_vec_map_cache_hasher : ggc_cache_ptr_hash<tree_vec_map>
+{
+ static hashval_t hash (tree_vec_map *m) { return DECL_UID (m->base.from); }
+
+ static bool
+ equal (tree_vec_map *a, tree_vec_map *b)
+ {
+ return a->base.from == b->base.from;
+ }
+
+ static int
+ keep_cache_entry (tree_vec_map *&m)
+ {
+ return ggc_marked_p (m->base.from);
+ }
+};
+
/* Hasher for tree decls. Pointer equality is enough here, but the DECL_UID
is a better hash than the pointer value and gives a predictable traversal
order. Additionally it can be used across PCH save/restore. */
@@ -13666,7 +13666,36 @@ tsubst_aggr_type (tree t,
}
}
-static GTY((cache)) decl_tree_cache_map *defarg_inst;
+/* Map from a FUNCTION_DECL to a vec of default argument instantiations. */
+
+static GTY((cache)) hash_table<tree_vec_map_cache_hasher> *defarg_inst;
+
+/* Return a reference to the slot for the defarg inst of PARM. */
+
+tree &
+defarg_inst_for (tree parm)
+{
+ if (!defarg_inst)
+ defarg_inst = hash_table<tree_vec_map_cache_hasher>::create_ggc (13);
+ tree fn = DECL_CONTEXT (parm);
+ tree_vec_map in = { fn, nullptr };
+ tree_vec_map **slot
+ = defarg_inst->find_slot_with_hash (&in, DECL_UID (fn), INSERT);
+ if (!*slot)
+ {
+ *slot = ggc_alloc<tree_vec_map> ();
+ **slot = in;
+ }
+
+ /* Index in reverse order to avoid allocating space for initial parameters
+ that don't have default arguments. */
+ unsigned ridx = list_length (parm);
+
+ vec<tree,va_gc> *&defs = (*slot)->to;
+ if (vec_safe_length (defs) < ridx)
+ vec_safe_grow_cleared (defs, ridx);
+ return (*defs)[ridx - 1];
+}
/* Substitute into the default argument ARG (a default argument for
FN), which has the indicated TYPE. */
@@ -13696,9 +13725,9 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, parmtype));
- tree *slot;
- if (defarg_inst && (slot = defarg_inst->get (parm)))
- return *slot;
+ tree &inst = defarg_inst_for (parm);
+ if (inst)
+ return inst;
/* This default argument came from a template. Instantiate the
default argument here, not in tsubst. In the case of
@@ -13743,11 +13772,7 @@ tsubst_default_argument (tree fn, int parmnum, tree type, tree arg,
pop_from_top_level ();
if (arg != error_mark_node && !cp_unevaluated_operand)
- {
- if (!defarg_inst)
- defarg_inst = decl_tree_cache_map::create_ggc (37);
- defarg_inst->put (parm, arg);
- }
+ inst = arg;
return arg;
}
new file mode 100644
@@ -0,0 +1,21 @@
+// PR c++/103186
+// { dg-do compile { target c++11 } }
+
+struct f
+{
+ template<class T1>
+ f(const T1&){}
+};
+
+
+template<typename T> class A {
+public:
+ void foo(A<T> a, const f& fn = [](){}) { }
+ void bar(A<T> a) { foo(a); }
+};
+int main() {
+ A<int> a;
+ a.foo(a);
+ a.bar(a);
+ return 0;
+}
@@ -242,23 +242,6 @@ static GTY ((cache))
static GTY ((cache))
hash_table<tree_decl_map_cache_hasher> *value_expr_for_decl;
-struct tree_vec_map_cache_hasher : ggc_cache_ptr_hash<tree_vec_map>
-{
- static hashval_t hash (tree_vec_map *m) { return DECL_UID (m->base.from); }
-
- static bool
- equal (tree_vec_map *a, tree_vec_map *b)
- {
- return a->base.from == b->base.from;
- }
-
- static int
- keep_cache_entry (tree_vec_map *&m)
- {
- return ggc_marked_p (m->base.from);
- }
-};
-
static GTY ((cache))
hash_table<tree_vec_map_cache_hasher> *debug_args_for_decl;