[PATCH] c++: Clear uninstantiated friend flag when instantiating [PR104234]

[PATCH] c++: Clear uninstantiated friend flag when instantiating [PR104234]

[Nathaniel Shead]

Bootstrapped and regtested on x86_64-pc-linux-gnu. I don't have write
access.

-- >8 --

Otherwise attempting to get the originating module declaration ICEs
because the DECL_CHAIN of an instantiated friend template is no longer
its context.

	PR c++/104234
        PR c++/112580

gcc/cp/ChangeLog:

	* pt.cc (tsubst_template_decl):

gcc/testsuite/ChangeLog:

	* g++.dg/modules/pr104234.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
 gcc/cp/pt.cc                            |  2 ++
 gcc/testsuite/g++.dg/modules/pr104234.C | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/modules/pr104234.C

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index ed681afb5d4..5e10a523e1a 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -14789,6 +14789,8 @@ tsubst_template_decl (tree t, tree args, tsubst_flags_t complain,
   if (PRIMARY_TEMPLATE_P (t))
     DECL_PRIMARY_TEMPLATE (r) = r;
 
+  DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (r) = false;
+
   if (!lambda_fntype && !class_p)
     {
       /* Record this non-type partial instantiation.  */
diff --git a/gcc/testsuite/g++.dg/modules/pr104234.C b/gcc/testsuite/g++.dg/modules/pr104234.C
new file mode 100644
index 00000000000..d81f0d435bc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr104234.C
@@ -0,0 +1,16 @@
+// PR c++/104234
+// { dg-additional-options "-fmodules-ts" }
+
+template <typename> struct _Node_handle_common {
+  template <typename> friend class _Rb_tree;
+};
+struct _Hashtable {
+  using node_type = _Node_handle_common<int>;
+  node_type __trans_tmp_1;
+};
+template <typename> class _Rb_tree {
+  struct _Rb_tree_impl {
+    _Rb_tree_impl();
+  } _M_impl;
+};
+_Rb_tree<int> _M_tmap_;
-- 
2.42.0

Re: [PATCH] c++: Clear uninstantiated friend flag when instantiating [PR104234]

[Nathaniel Shead]

Sorry, I just noticed I hadn't actually filled in the changelog. It
should say "Clear DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P."

On Thu, Nov 23, 2023 at 11:54 PM Nathaniel Shead
<nathanieloshead@gmail.com> wrote:
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu. I don't have write
> access.
>
> -- >8 --
>
> Otherwise attempting to get the originating module declaration ICEs
> because the DECL_CHAIN of an instantiated friend template is no longer
> its context.
>
>         PR c++/104234
>         PR c++/112580
>
> gcc/cp/ChangeLog:
>
>         * pt.cc (tsubst_template_decl):
>
> gcc/testsuite/ChangeLog:
>
>         * g++.dg/modules/pr104234.C: New test.
>
> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> ---
>  gcc/cp/pt.cc                            |  2 ++
>  gcc/testsuite/g++.dg/modules/pr104234.C | 16 ++++++++++++++++
>  2 files changed, 18 insertions(+)
>  create mode 100644 gcc/testsuite/g++.dg/modules/pr104234.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index ed681afb5d4..5e10a523e1a 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -14789,6 +14789,8 @@ tsubst_template_decl (tree t, tree args, tsubst_flags_t complain,
>    if (PRIMARY_TEMPLATE_P (t))
>      DECL_PRIMARY_TEMPLATE (r) = r;
>
> +  DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (r) = false;
> +
>    if (!lambda_fntype && !class_p)
>      {
>        /* Record this non-type partial instantiation.  */
> diff --git a/gcc/testsuite/g++.dg/modules/pr104234.C b/gcc/testsuite/g++.dg/modules/pr104234.C
> new file mode 100644
> index 00000000000..d81f0d435bc
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/pr104234.C
> @@ -0,0 +1,16 @@
> +// PR c++/104234
> +// { dg-additional-options "-fmodules-ts" }
> +
> +template <typename> struct _Node_handle_common {
> +  template <typename> friend class _Rb_tree;
> +};
> +struct _Hashtable {
> +  using node_type = _Node_handle_common<int>;
> +  node_type __trans_tmp_1;
> +};
> +template <typename> class _Rb_tree {
> +  struct _Rb_tree_impl {
> +    _Rb_tree_impl();
> +  } _M_impl;
> +};
> +_Rb_tree<int> _M_tmap_;
> --
> 2.42.0
>

Re: [PATCH] c++: Clear uninstantiated friend flag when instantiating [PR104234]

[Patrick Palka]

On Thu, 23 Nov 2023, Nathaniel Shead wrote:

> Bootstrapped and regtested on x86_64-pc-linux-gnu. I don't have write
> access.
> 
> -- >8 --
> 
> Otherwise attempting to get the originating module declaration ICEs
> because the DECL_CHAIN of an instantiated friend template is no longer
> its context.

Thanks for the patch!  I arrived at a similar fix back in January[1],
which Nathan reviewed[2], which then fell through the cracks...  My
patch was perhaps too ambitious as it tried to fix the ICE as well
as a follow-up module attachment issue.  But just clearing
DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (either in tsubst_template_decl or
more narrowly in tsubst_friend_class) seems pretty clearly correct and
fixes the reported ICEs so LGTM :) Thanks again!

[1]: https://gcc.gnu.org/pipermail/gcc-patches/2023-January/610593.html
[2]: https://gcc.gnu.org/pipermail/gcc-patches/2023-February/611215.html

> 
> 	PR c++/104234
>         PR c++/112580
> 
> gcc/cp/ChangeLog:
> 
> 	* pt.cc (tsubst_template_decl):
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/modules/pr104234.C: New test.
> 
> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> ---
>  gcc/cp/pt.cc                            |  2 ++
>  gcc/testsuite/g++.dg/modules/pr104234.C | 16 ++++++++++++++++
>  2 files changed, 18 insertions(+)
>  create mode 100644 gcc/testsuite/g++.dg/modules/pr104234.C
> 
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index ed681afb5d4..5e10a523e1a 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -14789,6 +14789,8 @@ tsubst_template_decl (tree t, tree args, tsubst_flags_t complain,
>    if (PRIMARY_TEMPLATE_P (t))
>      DECL_PRIMARY_TEMPLATE (r) = r;
>  
> +  DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (r) = false;
> +
>    if (!lambda_fntype && !class_p)
>      {
>        /* Record this non-type partial instantiation.  */
> diff --git a/gcc/testsuite/g++.dg/modules/pr104234.C b/gcc/testsuite/g++.dg/modules/pr104234.C
> new file mode 100644
> index 00000000000..d81f0d435bc
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/pr104234.C
> @@ -0,0 +1,16 @@
> +// PR c++/104234
> +// { dg-additional-options "-fmodules-ts" }
> +
> +template <typename> struct _Node_handle_common {
> +  template <typename> friend class _Rb_tree;
> +};
> +struct _Hashtable {
> +  using node_type = _Node_handle_common<int>;
> +  node_type __trans_tmp_1;
> +};
> +template <typename> class _Rb_tree {
> +  struct _Rb_tree_impl {
> +    _Rb_tree_impl();
> +  } _M_impl;
> +};
> +_Rb_tree<int> _M_tmap_;
> -- 
> 2.42.0
> 
> 

Re: [PATCH] c++: Clear uninstantiated friend flag when instantiating [PR104234]

[Marek Polacek]

On Thu, Nov 23, 2023 at 11:54:48PM +1100, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu. I don't have write
> access.

Based on your great contributions, you should get yourself write access;
please follow <https://gcc.gnu.org/gitwrite.html>.  I'm not certain the
rules allow me to be your sponsor, but I'm sure Jason or Nathan will
gladly approve.

Marek

Re: [PATCH] c++: Clear uninstantiated friend flag when instantiating [PR104234]

[Jason Merrill]

On 11/23/23 08:40, Nathaniel Shead wrote:
> Sorry, I just noticed I hadn't actually filled in the changelog. It
> should say "Clear DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P."

OK with that change.

> On Thu, Nov 23, 2023 at 11:54 PM Nathaniel Shead
> <nathanieloshead@gmail.com> wrote:
>>
>> Bootstrapped and regtested on x86_64-pc-linux-gnu. I don't have write
>> access.
>>
>> -- >8 --
>>
>> Otherwise attempting to get the originating module declaration ICEs
>> because the DECL_CHAIN of an instantiated friend template is no longer
>> its context.
>>
>>          PR c++/104234
>>          PR c++/112580
>>
>> gcc/cp/ChangeLog:
>>
>>          * pt.cc (tsubst_template_decl):
>>
>> gcc/testsuite/ChangeLog:
>>
>>          * g++.dg/modules/pr104234.C: New test.
>>
>> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
>> ---
>>   gcc/cp/pt.cc                            |  2 ++
>>   gcc/testsuite/g++.dg/modules/pr104234.C | 16 ++++++++++++++++
>>   2 files changed, 18 insertions(+)
>>   create mode 100644 gcc/testsuite/g++.dg/modules/pr104234.C
>>
>> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
>> index ed681afb5d4..5e10a523e1a 100644
>> --- a/gcc/cp/pt.cc
>> +++ b/gcc/cp/pt.cc
>> @@ -14789,6 +14789,8 @@ tsubst_template_decl (tree t, tree args, tsubst_flags_t complain,
>>     if (PRIMARY_TEMPLATE_P (t))
>>       DECL_PRIMARY_TEMPLATE (r) = r;
>>
>> +  DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (r) = false;
>> +
>>     if (!lambda_fntype && !class_p)
>>       {
>>         /* Record this non-type partial instantiation.  */
>> diff --git a/gcc/testsuite/g++.dg/modules/pr104234.C b/gcc/testsuite/g++.dg/modules/pr104234.C
>> new file mode 100644
>> index 00000000000..d81f0d435bc
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/modules/pr104234.C
>> @@ -0,0 +1,16 @@
>> +// PR c++/104234
>> +// { dg-additional-options "-fmodules-ts" }
>> +
>> +template <typename> struct _Node_handle_common {
>> +  template <typename> friend class _Rb_tree;
>> +};
>> +struct _Hashtable {
>> +  using node_type = _Node_handle_common<int>;
>> +  node_type __trans_tmp_1;
>> +};
>> +template <typename> class _Rb_tree {
>> +  struct _Rb_tree_impl {
>> +    _Rb_tree_impl();
>> +  } _M_impl;
>> +};
>> +_Rb_tree<int> _M_tmap_;
>> --
>> 2.42.0
>>
>