On Mon, 1 May 2023, Jason Merrill wrote:
> Tested x86_64-pc-linux-gnu, applying to trunk.
>
> Patrick, can you verify that this resolves 109506 and add whatever testcase(s)
> seem appropriate from that PR?
>
> -- 8< --
>
> Here it turns out I also needed to adjust cfun when stepping out of the
> member function to instantiate the DMI. But instead of adding that tweak,
> let's unify with instantiate_body and just push_to_top_level instead of
> trying to do the minimum subset of it. There was no measurable change in
> compile time on stdc++.h.
>
> This should also resolve 109506 without yet another tweak.
>
> PR c++/109666
>
> gcc/cp/ChangeLog:
>
> * name-lookup.cc (maybe_push_to_top_level)
> (maybe_pop_from_top_level): Split out...
> * pt.cc (instantiate_body): ...from here.
> * init.cc (maybe_instantiate_nsdmi_init): Use them.
> * name-lookup.h: Declare them..
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/nsdmi-array2.C: New test.
> ---
> gcc/cp/name-lookup.h | 2 ++
> gcc/cp/init.cc | 25 ++-------------
> gcc/cp/name-lookup.cc | 37 +++++++++++++++++++++++
> gcc/cp/pt.cc | 20 ++----------
> gcc/testsuite/g++.dg/cpp0x/nsdmi-array2.C | 15 +++++++++
> 5 files changed, 58 insertions(+), 41 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-array2.C
>
> diff --git a/gcc/cp/name-lookup.h b/gcc/cp/name-lookup.h
> index c234cd44356..b3e708561d8 100644
> --- a/gcc/cp/name-lookup.h
> +++ b/gcc/cp/name-lookup.h
> @@ -466,6 +466,8 @@ extern void push_nested_namespace (tree);
> extern void pop_nested_namespace (tree);
> extern void push_to_top_level (void);
> extern void pop_from_top_level (void);
> +extern bool maybe_push_to_top_level (tree);
> +extern void maybe_pop_from_top_level (bool);
> extern void push_using_decl_bindings (tree, tree);
>
> /* Lower level interface for modules. */
> diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
> index 1dd24e30d7c..0b35e1092e9 100644
> --- a/gcc/cp/init.cc
> +++ b/gcc/cp/init.cc
> @@ -597,32 +597,14 @@ maybe_instantiate_nsdmi_init (tree member,
> tsubst_flags_t complain)
> bool pushed = false;
> tree ctx = type_context_for_name_lookup (member);
>
> - processing_template_decl_sentinel ptds (/*reset*/false);
> + bool push_to_top = maybe_push_to_top_level (member);
> if (!currently_open_class (ctx))
> {
> - if (!LOCAL_CLASS_P (ctx))
> - push_to_top_level ();
> - else
> - /* push_to_top_level would lose the necessary function context,
> - just reset processing_template_decl. */
> - processing_template_decl = 0;
> push_nested_class (ctx);
> push_deferring_access_checks (dk_no_deferred);
> pushed = true;
> }
>
> - /* If we didn't push_to_top_level, still step out of constructor
> - scope so build_base_path doesn't try to use its __in_chrg. */
> - tree cfd = current_function_decl;
> - auto cbl = current_binding_level;
> - if (at_function_scope_p ())
> - {
> - current_function_decl
> - = decl_function_context (current_function_decl);
> - while (current_binding_level->kind != sk_class)
> - current_binding_level = current_binding_level->level_chain;
> - }
> -
> inject_this_parameter (ctx, TYPE_UNQUALIFIED);
>
> start_lambda_scope (member);
> @@ -639,15 +621,12 @@ maybe_instantiate_nsdmi_init (tree member,
> tsubst_flags_t complain)
> if (init != error_mark_node)
> DECL_INITIAL (member) = init;
>
> - current_function_decl = cfd;
> - current_binding_level = cbl;
> if (pushed)
> {
> pop_deferring_access_checks ();
> pop_nested_class ();
> - if (!LOCAL_CLASS_P (ctx))
> - pop_from_top_level ();
> }
> + maybe_pop_from_top_level (push_to_top);
>
> input_location = sloc;
> }
> diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
> index 477cddd7543..7c61bc3bf61 100644
> --- a/gcc/cp/name-lookup.cc
> +++ b/gcc/cp/name-lookup.cc
> @@ -8236,6 +8236,43 @@ pop_from_top_level (void)
> free_saved_scope = s;
> }
>
> +/* Like push_to_top_level, but not if D is function-local. Returns whether
> we
> + did push to top. */
> +
> +bool
> +maybe_push_to_top_level (tree d)
> +{
> + /* Push if D isn't function-local, or is a lambda function, for which name
> + resolution is already done. */
> + bool push_to_top
> + = !(current_function_decl
> + && !LAMBDA_FUNCTION_P (d)
> + && decl_function_context (d) == current_function_decl);
> +
> + if (push_to_top)
> + push_to_top_level ();
> + else
> + {
> + gcc_assert (!processing_template_decl);
> + push_function_context ();
> + cp_unevaluated_operand = 0;
> + c_inhibit_evaluation_warnings = 0;
I think we need to restore these flags in maybe_pop_from_top_level, like
so perhaps? Bootstrap and regtest running on x86_64-pc-linux-gnu.
-- >8 --
Subject: [PATCH] c++: missing state restoration in maybe_pop_from_top_level
gcc/cp/ChangeLog:
* name-lookup.cc (struct maybe_push_state_t): Define.
(maybe_push_state_stack): Define.
(maybe_push_to_top_level): Use them.
(maybe_pop_from_top_level): Likewise.
* pt.cc (instantiate_decl): Remove dead code for saving/restoring
cp_unevaluated_operand and c_inhibit_evaluation_warnings.
---
gcc/cp/name-lookup.cc | 37 ++++++++++++++++++++++++++++++++++---
gcc/cp/pt.cc | 4 ----
2 files changed, 34 insertions(+), 7 deletions(-)
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index 09dc6ef3e5a..aaedfaa45b3 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -8553,6 +8553,35 @@ pop_from_top_level (void)
free_saved_scope = s;
}
+/* Helper class for saving/restoring relevant global flags in the
+ function-local case of maybe_push_to_top_level. */
+
+struct maybe_push_state_t
+{
+ int cp_unevaluated_operand;
+ int c_inhibit_evaluation_warnings;
+
+ static maybe_push_state_t
+ save_and_clear ()
+ {
+ maybe_push_state_t s;
+ s.cp_unevaluated_operand = ::cp_unevaluated_operand;
+ ::cp_unevaluated_operand = 0;
+ s.c_inhibit_evaluation_warnings = ::c_inhibit_evaluation_warnings;
+ ::c_inhibit_evaluation_warnings = 0;
+ return s;
+ }
+
+ void
+ restore () const
+ {
+ ::cp_unevaluated_operand = this->cp_unevaluated_operand;
+ ::c_inhibit_evaluation_warnings = this->c_inhibit_evaluation_warnings;
+ }
+};
+
+static vec<maybe_push_state_t> maybe_push_state_stack;
+
/* Like push_to_top_level, but not if D is function-local. Returns whether we
did push to top. */
@@ -8572,8 +8601,7 @@ maybe_push_to_top_level (tree d)
{
gcc_assert (!processing_template_decl);
push_function_context ();
- cp_unevaluated_operand = 0;
- c_inhibit_evaluation_warnings = 0;
+ maybe_push_state_stack.safe_push (maybe_push_state_t::save_and_clear ());
}
return push_to_top;
@@ -8587,7 +8615,10 @@ maybe_pop_from_top_level (bool push_to_top)
if (push_to_top)
pop_from_top_level ();
else
- pop_function_context ();
+ {
+ maybe_push_state_stack.pop ().restore ();
+ pop_function_context ();
+ }
}
/* Push into the scope of the namespace NS, even if it is deeply
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index a82d7ae93aa..74da35596a5 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -26833,8 +26833,6 @@ instantiate_decl (tree d, bool defer_ok, bool
expl_inst_class_mem_p)
tree gen_tmpl;
bool pattern_defined;
location_t saved_loc = input_location;
- int saved_unevaluated_operand = cp_unevaluated_operand;
- int saved_inhibit_evaluation_warnings = c_inhibit_evaluation_warnings;
bool external_p;
bool deleted_p;
@@ -27071,8 +27069,6 @@ instantiate_decl (tree d, bool defer_ok, bool
expl_inst_class_mem_p)
pop_deferring_access_checks ();
pop_tinst_level ();
input_location = saved_loc;
- cp_unevaluated_operand = saved_unevaluated_operand;
- c_inhibit_evaluation_warnings = saved_inhibit_evaluation_warnings;
return d;
}
--
2.43.0.121.g624eb90fa8
