On Fri, Apr 26, 2024 at 09:16:40PM -0400, Jason Merrill wrote:
On 4/19/24 09:29, Nathaniel Shead wrote:
On Fri, Apr 19, 2024 at 12:14:06PM +1000, Nathaniel Shead wrote:
On Wed, Apr 17, 2024 at 02:02:21PM -0400, Patrick Palka wrote:
On Mon, 15 Apr 2024, Nathaniel Shead wrote:
I'm not a huge fan of always streaming 'imported_temploid_friends' for
all decls, but I don't think it adds much performance cost over adding a
new flag to categorise decls that might be marked as such.
IIUC this value is going to be almost always null which is encoded as a
single 0 byte, which should be fast to stream. But I wonder how much
larger <bits/stdc++.h> gets? Can we get away with streaming this value
only for TEMPLATE_DECLs?
Yes, it should either just be a 0 byte or an additional backref
somewhere, which will likely also be small. On my system it increases
the size by 0.26%, from 31186800 bytes to 31268672.
But I've just found that this patch has a bug anyway, in that it doesn't
correctly dedup if the friend types are instantiated in two separate
modules that are then both imported. I'll see what I need to do to fix
this which may influence what we need to stream here.
Here's an updated version of the patch that fixes this. Also changed to
only stream when 'inner' is either TYPE_DECL or FUNCTION_DECL, which
cuts the size of <bits/stdc++.h> down a bit to 31246992 (0.19% growth).
Another alternative would be to add another boolean flag at the top of
'decl_value' and branch on that; that would make use of the bitpacking
logic and probably cut down on the size further. (I haven't measured
this yet though.)
Bootstrapped and regtested (so far just dg.exp and modules.exp) on
x86_64-pc-linux-gnu, OK for trunk if full regtest succeeds?
-- >8 --
This patch fixes a number of issues with the handling of temploid friend
declarations.
The primary issue is that instantiations of friend declarations should
attach the declaration to the same module as the befriending class, by
[module.unit] p7.1 and [temp.friend] p2; this could be a different
module from the current TU, and so needs special handling.
This is only an issue for DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P, right?
It's true for any friend instantiations, including e.g. friend
functions, not just template class friends.
Hmm, CWG2588 should probably touch [module.unit]/7.1 as well as
[basic.link].
The other main issue here is that we can't assume that just because name
lookup didn't find a definition for a hidden template class, it doesn't
mean that it doesn't exist: it could be a non-exported entity that we've
nevertheless streamed in from an imported module. We need to ensure
that when instantiating friend classes that we return the same TYPE_DECL
that we got from our imports, otherwise we will get later issues with
'duplicate_decls' (rightfully) complaining that they're different.
Tricksy.
This doesn't appear necessary for functions due to the existing name
lookup handling already finding these hidden declarations.
PR c++/105320
PR c++/114275
gcc/cp/ChangeLog:
* cp-tree.h (propagate_defining_module): Declare.
(lookup_imported_hidden_friend): Declare.
* decl.cc (duplicate_decls): Also check if hidden declarations
can be redeclared in this module.
* module.cc (imported_temploid_friends): New map.
(init_modules): Initialize it.
(trees_out::decl_value): Write it; don't consider imported
temploid friends as attached to this module.
(trees_in::decl_value): Read it.
(depset::hash::add_specializations): Don't treat instantiations
of a friend type as a specialisation.
(get_originating_module_decl): Follow the owning decl for an
imported temploid friend.
(propagate_defining_module): New function.
* name-lookup.cc (lookup_imported_hidden_friend): New function.
* pt.cc (tsubst_friend_function): Propagate defining module for
new friend functions.
(tsubst_friend_class): Lookup imported hidden friends. Check
for valid redeclaration. Propagate defining module for new
friend classes.
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index aa66da4829d..56752cf6872 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -2276,30 +2276,34 @@ duplicate_decls (tree newdecl, tree olddecl, bool
hiding, bool was_hidden)
if (modules_p ()
&& TREE_CODE (CP_DECL_CONTEXT (olddecl)) == NAMESPACE_DECL
- && TREE_CODE (olddecl) != NAMESPACE_DECL
- && !hiding)
+ && TREE_CODE (olddecl) != NAMESPACE_DECL)
{
if (!module_may_redeclare (olddecl, newdecl))
return error_mark_node;
- tree not_tmpl = STRIP_TEMPLATE (olddecl);
- if (DECL_LANG_SPECIFIC (not_tmpl)
- && DECL_MODULE_ATTACH_P (not_tmpl)
- /* Typedefs are not entities and so are OK to be redeclared
- as exported: see [module.interface]/p6. */
- && TREE_CODE (olddecl) != TYPE_DECL)
+ if (!hiding)
{
- if (DECL_MODULE_EXPORT_P (STRIP_TEMPLATE (newdecl))
- && !DECL_MODULE_EXPORT_P (not_tmpl))
+ /* Hidden friend declarations just use exportingness of the
+ old declaration; see CWG2588. */
I'm not sure what this comment is trying to say, wouldn't hiding be true for
a hidden friend?
Right, it wasn't clear; the comment was meant to be explaining why we
don't do the following hunk for hidden friends, because for a hidden
friend we only care about the exportingness of OLDDECL (and NEWDECL
doesn't need to change). I've updated the comment to be clearer.
I took a closer look at the code as well and it doesn't seem to exactly
match the rules given by [module.interface] anyway, but I think that
should be fixed as a separate patch. (In particular, this allows
redeclaring any GM entity as exported even if the initial declaration
was not, whereas [module.interface] p2 only allows this for names
declared within header units.)
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 36e035544f4..bd3ab686543 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -2727,6 +2727,11 @@ vec<tree, va_heap, vl_embed> *post_load_decls;
typedef hash_map<tree, auto_vec<tree>> keyed_map_t;
static keyed_map_t *keyed_table;
+/* Instantiations of temploid friends imported from another module
+ need to be owned by the same module as their instantiating template.
+ This maps these to the template that instantiated them. */
+static hash_map<tree, tree> *imported_temploid_friends;
So IIUC the way to express the attachment to an imported module is by
association with an actually imported decl.
And the problem is that there's no current way to get from the result of
tsubst_friend_* to the original temploid friend; as tsubst_class_template
says, "The new TMPL is not an instantiation of anything, so we forget its
origins." And this map provides that lookup?
Rather than "their instantiating template" and "the template that
instantiated them" I'd just say "the temploid", maybe "the temploid they are
instantiated from".
I'd also change "owned" to "attached".
Yup, right. I'll change the comment.
@@ -13370,10 +13393,17 @@ depset::hash::add_specializations (bool decl_p)
int use_tpl = 0;
bool is_friend = false;
- if (decl_p && DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (entry->tmpl))
- /* A friend of a template. This is keyed to the
- instantiation. */
- is_friend = true;
+ if (DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (entry->tmpl))
+ {
+ if (decl_p)
+ /* A friend of a template. This is keyed to the
+ instantiation. */
+ is_friend = true;
+ else
+ /* An instantiated friend struct. Don't count this as
+ a specialization, it'll be picked up later. */
You mean, in propagate_defining_module?
Would it make sense to call propagate_defining_module here, rather than in
tsubst_friend_class?
No sorry, in 'add_namespace_entities'. The issue here is that even
though this isn't counted as a specialisation anymore, it's still kept
in 'type_specializations' as-if it was a dependent specialization of
the instantiating type. As such, e.g. for
template <typename T>
struct A {
template <typename> friend struct B;
};
Instantiating A<int> in one module and A<double> in a different module
will emit two different 'specialization' merge keys with two sets of
template parameters, the outermost set being 'int' for the former and
'double' for the latter, preventing deduplication.
An alternative here I've tried would be to instead also remove the new
entry from 'type_specializations' in 'tsubst_friend_class' (given that
it shouldn't be used anywhere else either); this might be the neater
approach so I've done it below, but happy either way.
Either way we need to do 'propagate_defining_module' earlier, because
this function only happens after parsing is complete but we need to
ensure that 'get_originating_module_decl' gives the correct values
before then.
@@ -18930,6 +18960,12 @@ get_originating_module_decl (tree decl)
&& DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (decl))
decl = TYPE_NAME (DECL_CHAIN (decl));
+ /* An imported temploid friend is attached to the same module the
+ befriending class was. */
+ if (imported_temploid_friends)
+ if (tree *slot = imported_temploid_friends->get (decl))
+ decl = *slot;
+
int use;
if (tree ti = node_template_info (decl, use))
{
I note that just below this is
decl = TI_TEMPLATE (ti);
if (TREE_CODE (decl) != TEMPLATE_DECL)
{
/* A friend template specialization. */
gcc_checking_assert (OVL_P (decl));
return global_namespace;
}
which seems to want to say "global module" for a friend template
specialization, rather than the correct module. Is this code obsolete with
this patch?
It doesn't look like it; removing this regresses e.g. tpl-friend-6_a.C,
and seems to be handling friend specializations of existing
declarations, whereas the imported_temploid_friends logic is for
handling names first declared as friends.
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index 7af7f00e34c..dd6e7b6eaea 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -4453,6 +4453,48 @@ push_local_binding (tree id, tree decl, bool is_using)
add_decl_to_level (b, decl);
}
+/* Lookup the FRIEND_TMPL within all module imports. Used to dedup
+ instantiations of temploid hidden friends from imported modules. */
+
+tree
+lookup_imported_hidden_friend (tree friend_tmpl)
+{
+ tree inner = DECL_TEMPLATE_RESULT (friend_tmpl);
+ if (!DECL_LANG_SPECIFIC (inner)
+ || !DECL_MODULE_IMPORT_P (inner))
+ return NULL_TREE;
+
+ tree name = DECL_NAME (inner);
+ tree *slot = find_namespace_slot (current_namespace, name);
Maybe checking_assert CP_DECL_CONTEXT (friend_tmpl) == current_namespace?
Initially I hadn't because I thought that the context could possibly be
a class type. But if that was the case then I suppose that the original
lookup_name must succeed, so this assert should hold.
+ if (!slot || !*slot || TREE_CODE (*slot) != BINDING_VECTOR)
+ return NULL_TREE;
+
+ /* Look in the appropriate slot, as with check_module_override. */
+ binding_slot mslot;
+ if (named_module_p ())
+ mslot = BINDING_VECTOR_CLUSTER (*slot, BINDING_SLOT_PARTITION
+ / BINDING_VECTOR_SLOTS_PER_CLUSTER)
+ .slots[BINDING_SLOT_PARTITION % BINDING_VECTOR_SLOTS_PER_CLUSTER];
+ else
+ mslot = BINDING_VECTOR_CLUSTER (*slot, 0).slots[BINDING_SLOT_GLOBAL];
+ gcc_assert (!mslot.is_lazy ());
+
+ tree ovl = mslot;
+ if (!ovl)
+ return NULL_TREE;
+
+ /* We're only interested in declarations coming from the same module
+ of the friend class we're attempting to instantiate. */
+ int m = get_originating_module (friend_tmpl);
+ gcc_assert (m != 0);
+
+ for (ovl_iterator iter (ovl); iter; ++iter)
+ if (get_originating_module (*iter) == m)
+ return *iter;
+
+ return NULL_TREE;
+}
Maybe factor much of this out into a get_namespace_binding_in_module
function?
I've factored and clarified the slot-finding parts into a new
'get_mergeable_namespace_binding' to correspond with
'add_mergeable_namespace_entity'. Most of the rest I think relies on
implementation details specific to handling friend classes, I've added
some more comments too to expand on that.
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 3b2106dd3f6..e7e7f2fbc3b 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -11723,6 +11733,11 @@ tsubst_friend_class (tree friend_tmpl, tree args)
of course. We only need the innermost template parameters
because that is all that redeclare_class_template will look
at. */
+
+ if (modules_p ())
+ /* Check that we can redeclare TMPL in the current context. */
+ module_may_redeclare (tmpl, friend_tmpl);
Isn't this redundant with the duplicate_decls change?
No, because in this code path 'duplicate_decls' never actually gets
called: we just return the existing declaration directly. And this
check is needed for tpl-friend-13_[ce].C. Maybe we should be, but there
isn't really a corresponding 'olddecl' to compare with that I can see,
since friend_tmpl is just the template we're instantiating from rather
than a duplicate.
I've updated the comment to hopefully make it a bit clearer what this
check is actually doing.
Here's an updated version of the patch. Bootstrapped and regtested on
x86_64-pc-linux-gnu, OK for trunk?
-- >8 --
This patch fixes a number of issues with the handling of temploid friend
declarations.
The primary issue is that instantiations of friend declarations should
attach the declaration to the same module as the befriending class, by
[module.unit] p7.1 and [temp.friend] p2; this could be a different
module from the current TU, and so needs special handling.
The other main issue here is that we can't assume that just because name
lookup didn't find a definition for a hidden class template, that it
doesn't exist at all: it could be a non-exported entity that we've
nevertheless streamed in from an imported module. We need to ensure
that when instantiating template friend classes that we return the same
TEMPLATE_DECL that we got from our imports, otherwise we will get later
issues with 'duplicate_decls' (rightfully) complaining that they're
different when trying to merge.
This doesn't appear necessary for function templates due to the existing
name lookup handling already finding these hidden declarations.
PR c++/105320
PR c++/114275
gcc/cp/ChangeLog:
* cp-tree.h (propagate_defining_module): Declare.
(lookup_imported_hidden_friend): Declare.
* decl.cc (duplicate_decls): Also check if hidden decls can be
redeclared in this module.
* module.cc (imported_temploid_friends): New.
(init_modules): Initialize it.
(trees_out::decl_value): Write it; don't consider imported
temploid friends as attached to a module.
(trees_in::decl_value): Read it.
(get_originating_module_decl): Follow the owning decl for an
imported temploid friend.
(propagate_defining_module): New.
* name-lookup.cc (get_mergeable_namespace_binding): New.
(lookup_imported_hidden_friend): New.
* pt.cc (tsubst_friend_function): Propagate defining module for
new friend functions.
(tsubst_friend_class): Lookup imported hidden friends. Check
for valid module attachment of existing names. Propagate
defining module for new classes.
gcc/testsuite/ChangeLog:
* g++.dg/modules/tpl-friend-10_a.C: New test.
* g++.dg/modules/tpl-friend-10_b.C: New test.
* g++.dg/modules/tpl-friend-10_c.C: New test.
* g++.dg/modules/tpl-friend-10_d.C: New test.
* g++.dg/modules/tpl-friend-11_a.C: New test.
* g++.dg/modules/tpl-friend-11_b.C: New test.
* g++.dg/modules/tpl-friend-12_a.C: New test.
* g++.dg/modules/tpl-friend-12_b.C: New test.
* g++.dg/modules/tpl-friend-12_c.C: New test.
* g++.dg/modules/tpl-friend-12_d.C: New test.
* g++.dg/modules/tpl-friend-12_e.C: New test.
* g++.dg/modules/tpl-friend-12_f.C: New test.
* g++.dg/modules/tpl-friend-13_a.C: New test.
* g++.dg/modules/tpl-friend-13_b.C: New test.
* g++.dg/modules/tpl-friend-13_c.C: New test.
* g++.dg/modules/tpl-friend-13_d.C: New test.
* g++.dg/modules/tpl-friend-13_e.C: New test.
* g++.dg/modules/tpl-friend-13_f.C: New test.
* g++.dg/modules/tpl-friend-13_g.C: New test.
* g++.dg/modules/tpl-friend-14_a.C: New test.
* g++.dg/modules/tpl-friend-14_b.C: New test.
* g++.dg/modules/tpl-friend-14_c.C: New test.
* g++.dg/modules/tpl-friend-14_d.C: New test.
* g++.dg/modules/tpl-friend-9.C: New test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
---
gcc/cp/cp-tree.h | 2 +
gcc/cp/decl.cc | 37 ++++++-----
gcc/cp/module.cc | 62 +++++++++++++++++++
gcc/cp/name-lookup.cc | 53 ++++++++++++++++
gcc/cp/pt.cc | 29 ++++++++-
.../g++.dg/modules/tpl-friend-10_a.C | 15 +++++
.../g++.dg/modules/tpl-friend-10_b.C | 5 ++
.../g++.dg/modules/tpl-friend-10_c.C | 7 +++
.../g++.dg/modules/tpl-friend-10_d.C | 8 +++
.../g++.dg/modules/tpl-friend-11_a.C | 14 +++++
.../g++.dg/modules/tpl-friend-11_b.C | 5 ++
.../g++.dg/modules/tpl-friend-12_a.C | 10 +++
.../g++.dg/modules/tpl-friend-12_b.C | 9 +++
.../g++.dg/modules/tpl-friend-12_c.C | 10 +++
.../g++.dg/modules/tpl-friend-12_d.C | 8 +++
.../g++.dg/modules/tpl-friend-12_e.C | 7 +++
.../g++.dg/modules/tpl-friend-12_f.C | 8 +++
.../g++.dg/modules/tpl-friend-13_a.C | 13 ++++
.../g++.dg/modules/tpl-friend-13_b.C | 11 ++++
.../g++.dg/modules/tpl-friend-13_c.C | 13 ++++
.../g++.dg/modules/tpl-friend-13_d.C | 7 +++
.../g++.dg/modules/tpl-friend-13_e.C | 18 ++++++
.../g++.dg/modules/tpl-friend-13_f.C | 7 +++
.../g++.dg/modules/tpl-friend-13_g.C | 11 ++++
.../g++.dg/modules/tpl-friend-14_a.C | 8 +++
.../g++.dg/modules/tpl-friend-14_b.C | 8 +++
.../g++.dg/modules/tpl-friend-14_c.C | 7 +++
.../g++.dg/modules/tpl-friend-14_d.C | 9 +++
gcc/testsuite/g++.dg/modules/tpl-friend-9.C | 13 ++++
29 files changed, 397 insertions(+), 17 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-10_a.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-10_b.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-10_c.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-10_d.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-11_a.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-11_b.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-12_a.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-12_b.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-12_c.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-12_d.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-12_e.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-12_f.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_a.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_b.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_c.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_d.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_e.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_f.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-13_g.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-14_a.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-14_b.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-14_c.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-14_d.C
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-9.C
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index faa7a0052a5..67cc7d7bcec 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7417,6 +7417,7 @@ extern unsigned get_importing_module (tree, bool = false)
ATTRIBUTE_PURE;
extern void set_instantiating_module (tree);
extern void set_defining_module (tree);
extern void maybe_key_decl (tree ctx, tree decl);
+extern void propagate_defining_module (tree decl, tree orig);
extern void mangle_module (int m, bool include_partition);
extern void mangle_module_fini ();
@@ -7649,6 +7650,7 @@ extern bool template_guide_p
(const_tree);
extern bool builtin_guide_p (const_tree);
extern void store_explicit_specifier (tree, tree);
extern tree lookup_explicit_specifier (tree);
+extern tree lookup_imported_hidden_friend (tree);
extern void walk_specializations (bool,
void (*)(bool, spec_entry *,
void *),
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 91268ff631d..d88e0698652 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -2276,30 +2276,35 @@ duplicate_decls (tree newdecl, tree olddecl, bool
hiding, bool was_hidden)
if (modules_p ()
&& TREE_CODE (CP_DECL_CONTEXT (olddecl)) == NAMESPACE_DECL
- && TREE_CODE (olddecl) != NAMESPACE_DECL
- && !hiding)
+ && TREE_CODE (olddecl) != NAMESPACE_DECL)
{
if (!module_may_redeclare (olddecl, newdecl))
return error_mark_node;
- tree not_tmpl = STRIP_TEMPLATE (olddecl);
- if (DECL_LANG_SPECIFIC (not_tmpl)
- && DECL_MODULE_ATTACH_P (not_tmpl)
- /* Typedefs are not entities and so are OK to be redeclared
- as exported: see [module.interface]/p6. */
- && TREE_CODE (olddecl) != TYPE_DECL)
+ if (!hiding)
{
- if (DECL_MODULE_EXPORT_P (STRIP_TEMPLATE (newdecl))
- && !DECL_MODULE_EXPORT_P (not_tmpl))
+ /* The old declaration should match the exportingness of the new
+ declaration. But hidden friend declarations just keep the
+ exportingness of the old declaration; see CWG2588. */
+ tree not_tmpl = STRIP_TEMPLATE (olddecl);
+ if (DECL_LANG_SPECIFIC (not_tmpl)
+ && DECL_MODULE_ATTACH_P (not_tmpl)
+ /* Typedefs are not entities and so are OK to be redeclared
+ as exported: see [module.interface]/p6. */
+ && TREE_CODE (olddecl) != TYPE_DECL)
{
- auto_diagnostic_group d;
- error ("conflicting exporting for declaration %qD", newdecl);
- inform (olddecl_loc,
- "previously declared here without exporting");
+ if (DECL_MODULE_EXPORT_P (newdecl)
+ && !DECL_MODULE_EXPORT_P (not_tmpl))
+ {
+ auto_diagnostic_group d;
+ error ("conflicting exporting for declaration %qD", newdecl);
+ inform (olddecl_loc,
+ "previously declared here without exporting");
+ }
}
+ else if (DECL_MODULE_EXPORT_P (newdecl))
+ DECL_MODULE_EXPORT_P (not_tmpl) = true;
}
- else if (DECL_MODULE_EXPORT_P (newdecl))
- DECL_MODULE_EXPORT_P (not_tmpl) = true;
}
/* We have committed to returning OLDDECL at this point. */
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 0e2e60f85ae..c5141e5245b 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -2727,6 +2727,12 @@ vec<tree, va_heap, vl_embed> *post_load_decls;
typedef hash_map<tree, auto_vec<tree>> keyed_map_t;
static keyed_map_t *keyed_table;
+/* Instantiations of temploid friends imported from another module
+ need to be attached to the same module as the temploid. This maps
+ these decls to the temploid they are instantiated them, as there is
+ no other easy way to get this information. */
+static hash_map<tree, tree> *imported_temploid_friends;
+
/********************************************************************/
/* Tree streaming. The tree streaming is very specific to the tree
structures themselves. A tag indicates the kind of tree being
@@ -7820,6 +7826,12 @@ trees_out::decl_value (tree decl, depset *dep)
&& DECL_MODULE_ATTACH_P (not_tmpl))
is_attached = true;
+ /* But don't consider imported temploid friends as attached,
+ since importers will need to merge this decl even if it was
+ attached to a different module. */
+ if (imported_temploid_friends->get (decl))
+ is_attached = false;
+
bits.b (is_attached);
}
bits.b (dep && dep->has_defn ());
@@ -7997,6 +8009,15 @@ trees_out::decl_value (tree decl, depset *dep)
}
}
+ if (TREE_CODE (inner) == FUNCTION_DECL
+ || TREE_CODE (inner) == TYPE_DECL)
+ {
+ /* Write imported temploid friends so that importers can reconstruct
+ this information on stream-in. */
+ tree* slot = imported_temploid_friends->get (decl);
+ tree_node (slot ? *slot : NULL_TREE);
+ }
+
bool is_typedef = false;
if (!type && TREE_CODE (inner) == TYPE_DECL)
{
@@ -8303,6 +8324,11 @@ trees_in::decl_value ()
}
}
+ if (TREE_CODE (inner) == FUNCTION_DECL
+ || TREE_CODE (inner) == TYPE_DECL)
+ if (tree owner = tree_node ())
+ imported_temploid_friends->put (decl, owner);
+
/* Regular typedefs will have a NULL TREE_TYPE at this point. */
unsigned tdef_flags = 0;
bool is_typedef = false;
@@ -18939,6 +18965,12 @@ get_originating_module_decl (tree decl)
&& DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (decl))
decl = TYPE_NAME (DECL_CHAIN (decl));
+ /* An imported temploid friend is attached to the same module the
+ befriending class was. */
+ if (imported_temploid_friends)
+ if (tree *slot = imported_temploid_friends->get (decl))
+ decl = *slot;
+
int use;
if (tree ti = node_template_info (decl, use))
{
@@ -19247,6 +19279,34 @@ maybe_key_decl (tree ctx, tree decl)
vec.safe_push (decl);
}
+/* DECL is an instantiated friend that should be attached to the same
+ module that ORIG is. */
+
+void
+propagate_defining_module (tree decl, tree orig)
+{
+ if (!modules_p ())
+ return;
+
+ tree not_tmpl = STRIP_TEMPLATE (orig);
+ if (DECL_LANG_SPECIFIC (not_tmpl) && DECL_MODULE_ATTACH_P (not_tmpl))
+ {
+ tree inner = STRIP_TEMPLATE (decl);
+ retrofit_lang_decl (inner);
+ DECL_MODULE_ATTACH_P (inner) = true;
+ }
+
+ if (DECL_LANG_SPECIFIC (not_tmpl) && DECL_MODULE_IMPORT_P (not_tmpl))
+ {
+ bool exists = imported_temploid_friends->put (decl, orig);
+
+ /* We should only be called if lookup for an existing decl
+ failed, in which case there shouldn't already be an entry
+ in the map. */
+ gcc_assert (!exists);
+ }
+}
+
/* Create the flat name string. It is simplest to have it handy. */
void
@@ -20460,6 +20520,8 @@ init_modules (cpp_reader *reader)
pending_table = new pending_map_t (EXPERIMENT (1, 400));
entity_map = new entity_map_t (EXPERIMENT (1, 400));
vec_safe_reserve (entity_ary, EXPERIMENT (1, 400));
+ imported_temploid_friends
+ = new hash_map<tree,tree> (EXPERIMENT (1, 400));
}
#if CHECKING_P
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index 7af7f00e34c..4dffc0e9acc 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -4131,6 +4131,22 @@ mergeable_namespace_slots (tree ns, tree name, bool
is_attached, tree *vec)
return vslot;
}
+/* Retrieve the bindings for an existing mergeable entity in namespace
+ NS slot NAME. Returns NULL if no such bindings exists. */
+
+static tree
+get_mergeable_namespace_binding (tree ns, tree name, bool is_attached)
+{
+ tree *mslot = find_namespace_slot (ns, name, false);
+ if (!mslot || !*mslot || TREE_CODE (*mslot) != BINDING_VECTOR)
+ return NULL_TREE;
+
+ tree *vslot = get_fixed_binding_slot
+ (mslot, name, is_attached ? BINDING_SLOT_PARTITION : BINDING_SLOT_GLOBAL,
+ false);
+ return vslot ? *vslot : NULL_TREE;
+}
+
/* DECL is a new mergeable namespace-scope decl. Add it to the
mergeable entities on GSLOT. */
@@ -4453,6 +4469,43 @@ push_local_binding (tree id, tree decl, bool is_using)
add_decl_to_level (b, decl);
}
+/* Lookup the FRIEND_TMPL within all merged module imports. Used to dedup
+ instantiations of temploid hidden friends from imported modules. */
+
+tree
+lookup_imported_hidden_friend (tree friend_tmpl)
+{
+ /* For a class-scope friend class it should have been found by regular
+ name lookup. Otherwise we're looking in the current namespace. */
+ gcc_checking_assert (CP_DECL_CONTEXT (friend_tmpl) == current_namespace);
+
+ tree inner = DECL_TEMPLATE_RESULT (friend_tmpl);
+ if (!DECL_LANG_SPECIFIC (inner)
+ || !DECL_MODULE_IMPORT_P (inner))
+ return NULL_TREE;
+
+ /* Imported temploid friends are not considered as attached to this
+ module for merging purposes. */
+ tree bind = get_mergeable_namespace_binding (current_namespace,
+ DECL_NAME (inner), false);
+ if (!bind)
+ return NULL_TREE;
+
+ /* We're only interested in declarations coming from the same module
+ of the friend class we're attempting to instantiate. */
+ int m = get_originating_module (friend_tmpl);
+ gcc_assert (m != 0);
+
+ /* There should be at most one class template from the module we're
+ looking for, return it. */
+ for (ovl_iterator iter (bind); iter; ++iter)
+ if (DECL_CLASS_TEMPLATE_P (*iter)
+ && get_originating_module (*iter) == m)
+ return *iter;
+
+ return NULL_TREE;
+}
+
/* true means unconditionally make a BLOCK for the next level pushed. */
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 3b2106dd3f6..1c3eef60c06 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -11512,6 +11512,10 @@ tsubst_friend_function (tree decl, tree args)
new_friend_result_template_info = DECL_TEMPLATE_INFO (not_tmpl);
}
+ /* We need to propagate module attachment for the new friend from the
+ owner of this template. */
+ propagate_defining_module (new_friend, decl);
+
/* Inside pushdecl_namespace_level, we will push into the
current namespace. However, the friend function should go
into the namespace of the template. */
@@ -11715,6 +11719,12 @@ tsubst_friend_class (tree friend_tmpl, tree args)
tmpl = lookup_name (DECL_NAME (friend_tmpl), LOOK_where::CLASS_NAMESPACE,
LOOK_want::NORMAL | LOOK_want::HIDDEN_FRIEND);
+ if (!tmpl)
+ /* If we didn't find by name lookup, the type may still exist but as a
+ 'hidden' import; we should check for this too to avoid accidentally
+ instantiating a duplicate. */
+ tmpl = lookup_imported_hidden_friend (friend_tmpl);
+
if (tmpl && DECL_CLASS_TEMPLATE_P (tmpl))
{
/* The friend template has already been declared. Just
@@ -11723,6 +11733,12 @@ tsubst_friend_class (tree friend_tmpl, tree args)
of course. We only need the innermost template parameters
because that is all that redeclare_class_template will look
at. */
+
+ if (modules_p ())
+ /* Check that the existing declaration's module attachment is
+ compatible with the attachment of the friend template. */
+ module_may_redeclare (tmpl, friend_tmpl);
+
if (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (friend_tmpl))
> TMPL_ARGS_DEPTH (args))
{
@@ -11751,9 +11767,16 @@ tsubst_friend_class (tree friend_tmpl, tree args)
if (tmpl != error_mark_node)
{
/* The new TMPL is not an instantiation of anything, so we
- forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
+ forget its origins. It is also not a specialization of
+ anything. We don't reset CLASSTYPE_TI_TEMPLATE
for the new type because that is supposed to be the
corresponding template decl, i.e., TMPL. */
+ spec_entry elt;
+ elt.tmpl = friend_tmpl;
+ elt.args = CLASSTYPE_TI_ARGS (TREE_TYPE (tmpl));
+ elt.spec = TREE_TYPE (tmpl);
+ type_specializations->remove_elt (&elt);
