diff mbox series

[v2] c++: ICE with noexcept and local specialization, again [PR114349]

Message ID Zf34YBp3H16HJIRS@redhat.com
State New
Headers show
Series [v2] c++: ICE with noexcept and local specialization, again [PR114349] | expand

Commit Message

Marek Polacek March 22, 2024, 9:30 p.m. UTC 
On Thu, Mar 21, 2024 at 05:27:37PM -0400, Jason Merrill wrote:
> On 3/21/24 17:01, Marek Polacek wrote:
> > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > 
> > -- >8 --
> > Patrick noticed that my r14-9339-gdc6c3bfb59baab patch is wrong;
> > we're dealing with a noexcept-spec there, not a noexcept-expr, so
> > setting cp_noexcept_operand et al is incorrect.  Back to the drawing
> > board then.
> > 
> > To fix noexcept84.C, we should probably avoid doing push_to_top_level
> > in certain cases.  Patrick suggested checking:
> > 
> >    const bool push_to_top = current_function_decl != fn;
> > 
> > which works, but I'm not sure I follow the logic there.  I also came
> > up with
> > 
> >    const bool push_to_top = !decl_function_context (fn);
> > 
> > which also works.  But ultimately I went with !DECL_TEMPLATE_INSTANTIATED;
> > if DECL_TEMPLATE_INSTANTIATED is set, we've already pushed to top level
> > if it was necessary in instantiate_body.
> 
> This sort of thing is what maybe_push_to_top_level is for, does that also
> work?

Sadly -- and I should have mentioned that -- no.  maybe_push_to_top_level asks:

  bool push_to_top
    = !(current_function_decl
   && !LAMBDA_FUNCTION_P (d)
   && decl_function_context (d) == current_function_decl);

here both d and current_function_decl are test()::S::S(), and
decl_function_context (d) is test().  (current_function_decl was
set to test()::S::S() by an earlier push_access_scope call.)

But I want it to work, and I think using maybe_ would be a way nicer
fix.  So what if we don't push to top level if decl_function_context
is non-null?  I had to add the LAMBDA_TYPE_P check though: it looks
that we always have to push to top level for lambdas, but sometimes
we get a lambda's TYPE_DECL, and LAMBDA_FUNCTION_P doesn't catch
that.  An example is lambda-nested4.C.

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --
Patrick noticed that my r14-9339-gdc6c3bfb59baab patch is wrong;
we're dealing with a noexcept-spec there, not a noexcept-expr, so
setting cp_noexcept_operand et al is incorrect.  Back to the drawing
board then.

To fix noexcept84.C, we should probably avoid doing push_to_top_level
in certain cases.  maybe_push_to_top_level didn't work here as-is, so
I changed it to not push to top level if decl_function_context is
non-null, when we are not dealing with a lambda.

This also fixes c++/114349, introduced by r14-9339.

	PR c++/114349

gcc/cp/ChangeLog:

	* name-lookup.cc (maybe_push_to_top_level): For a non-lambda,
	don't push to top level if decl_function_context is non-null.
	* pt.cc (maybe_instantiate_noexcept): Use maybe_push_to_top_level.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/noexcept85.C: New test.
	* g++.dg/cpp0x/noexcept86.C: New test.
---
 gcc/cp/name-lookup.cc                   | 12 ++++++---
 gcc/cp/pt.cc                            | 11 ++-------
 gcc/testsuite/g++.dg/cpp0x/noexcept85.C | 33 +++++++++++++++++++++++++
 gcc/testsuite/g++.dg/cpp0x/noexcept86.C | 25 +++++++++++++++++++
 4 files changed, 68 insertions(+), 13 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept85.C
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept86.C


base-commit: 65b7d1862e11784a0ce67ab758e06dd8aa65b181

Comments

Jason Merrill March 25, 2024, 7:40 p.m. UTC | #1 
On 3/22/24 17:30, Marek Polacek wrote:
> On Thu, Mar 21, 2024 at 05:27:37PM -0400, Jason Merrill wrote:
>> On 3/21/24 17:01, Marek Polacek wrote:
>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>>>
>>> -- >8 --
>>> Patrick noticed that my r14-9339-gdc6c3bfb59baab patch is wrong;
>>> we're dealing with a noexcept-spec there, not a noexcept-expr, so
>>> setting cp_noexcept_operand et al is incorrect.  Back to the drawing
>>> board then.
>>>
>>> To fix noexcept84.C, we should probably avoid doing push_to_top_level
>>> in certain cases.  Patrick suggested checking:
>>>
>>>     const bool push_to_top = current_function_decl != fn;
>>>
>>> which works, but I'm not sure I follow the logic there.  I also came
>>> up with
>>>
>>>     const bool push_to_top = !decl_function_context (fn);
>>>
>>> which also works.  But ultimately I went with !DECL_TEMPLATE_INSTANTIATED;
>>> if DECL_TEMPLATE_INSTANTIATED is set, we've already pushed to top level
>>> if it was necessary in instantiate_body.
>>
>> This sort of thing is what maybe_push_to_top_level is for, does that also
>> work?
> 
> Sadly -- and I should have mentioned that -- no.  maybe_push_to_top_level asks:
> 
>    bool push_to_top
>      = !(current_function_decl
>     && !LAMBDA_FUNCTION_P (d)
>     && decl_function_context (d) == current_function_decl);
> 
> here both d and current_function_decl are test()::S::S(), and
> decl_function_context (d) is test().  (current_function_decl was
> set to test()::S::S() by an earlier push_access_scope call.)
> 
> But I want it to work, and I think using maybe_ would be a way nicer
> fix.  So what if we don't push to top level if decl_function_context
> is non-null?  I had to add the LAMBDA_TYPE_P check though: it looks
> that we always have to push to top level for lambdas, but sometimes
> we get a lambda's TYPE_DECL, and LAMBDA_FUNCTION_P doesn't catch
> that.  An example is lambda-nested4.C.
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> 
> -- >8 --
> Patrick noticed that my r14-9339-gdc6c3bfb59baab patch is wrong;
> we're dealing with a noexcept-spec there, not a noexcept-expr, so
> setting cp_noexcept_operand et al is incorrect.  Back to the drawing
> board then.
> 
> To fix noexcept84.C, we should probably avoid doing push_to_top_level
> in certain cases.  maybe_push_to_top_level didn't work here as-is, so
> I changed it to not push to top level if decl_function_context is
> non-null, when we are not dealing with a lambda.
> 
> This also fixes c++/114349, introduced by r14-9339.
> 
> 	PR c++/114349
> 
> gcc/cp/ChangeLog:
> 
> 	* name-lookup.cc (maybe_push_to_top_level): For a non-lambda,
> 	don't push to top level if decl_function_context is non-null.
> 	* pt.cc (maybe_instantiate_noexcept): Use maybe_push_to_top_level.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/cpp0x/noexcept85.C: New test.
> 	* g++.dg/cpp0x/noexcept86.C: New test.
> ---
>   gcc/cp/name-lookup.cc                   | 12 ++++++---
>   gcc/cp/pt.cc                            | 11 ++-------
>   gcc/testsuite/g++.dg/cpp0x/noexcept85.C | 33 +++++++++++++++++++++++++
>   gcc/testsuite/g++.dg/cpp0x/noexcept86.C | 25 +++++++++++++++++++
>   4 files changed, 68 insertions(+), 13 deletions(-)
>   create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept85.C
>   create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept86.C
> 
> diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
> index dce4caf8981..4b2b27bdd0d 100644
> --- a/gcc/cp/name-lookup.cc
> +++ b/gcc/cp/name-lookup.cc
> @@ -8664,10 +8664,14 @@ 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);
> +  const bool push_to_top
> +    = (LAMBDA_FUNCTION_P (d)
> +       || (TREE_CODE (d) == TYPE_DECL
> +	   && TREE_TYPE (d)
> +	   && LAMBDA_TYPE_P (TREE_TYPE (d)))
> +       || !current_function_decl
> +       || (!decl_function_context (d)
> +	   && decl_function_context (d) != current_function_decl));

This line seems unnecessary; the case it excludes is when 
decl_function_context and current_function_decl are both null, but if 
current_function_decl is null we already succeeded.

OK with this line removed.

>     if (push_to_top)
>       push_to_top_level ();
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 8cf0d5b7a8d..7b00a8615d2 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -26855,7 +26855,7 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
>   	}
>         else if (push_tinst_level (fn))
>   	{
> -	  push_to_top_level ();
> +	  const bool push_to_top = maybe_push_to_top_level (fn);
>   	  push_access_scope (fn);
>   	  push_deferring_access_checks (dk_no_deferred);
>   	  input_location = DECL_SOURCE_LOCATION (fn);
> @@ -26878,17 +26878,10 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
>   	  if (orig_fn)
>   	    ++processing_template_decl;
>   
> -	  ++cp_unevaluated_operand;
> -	  ++c_inhibit_evaluation_warnings;
> -	  ++cp_noexcept_operand;
>   	  /* Do deferred instantiation of the noexcept-specifier.  */
>   	  noex = tsubst_expr (DEFERRED_NOEXCEPT_PATTERN (noex),
>   			      DEFERRED_NOEXCEPT_ARGS (noex),
>   			      tf_warning_or_error, fn);
> -	  --cp_unevaluated_operand;
> -	  --c_inhibit_evaluation_warnings;
> -	  --cp_noexcept_operand;
> -
>   	  /* Build up the noexcept-specification.  */
>   	  spec = build_noexcept_spec (noex, tf_warning_or_error);
>   
> @@ -26898,7 +26891,7 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
>   	  pop_deferring_access_checks ();
>   	  pop_access_scope (fn);
>   	  pop_tinst_level ();
> -	  pop_from_top_level ();
> +	  maybe_pop_from_top_level (push_to_top);
>   	}
>         else
>   	spec = noexcept_false_spec;
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept85.C b/gcc/testsuite/g++.dg/cpp0x/noexcept85.C
> new file mode 100644
> index 00000000000..b415bb46bc9
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept85.C
> @@ -0,0 +1,33 @@
> +// PR c++/114349
> +// { dg-do compile { target c++11 } }
> +
> +using A = struct {};
> +template <template <typename> class, typename, typename>
> +using B = A;
> +template <typename T>
> +using C = typename T::D;
> +struct E {
> +  using D = B<C, int, A>;
> +};
> +template <class> constexpr bool foo (A) { return false; }
> +template <class T> struct F {
> +  using G = T;
> +  using H = E;
> +  F(const F &);
> +  void operator=(F) noexcept(foo <G> (H::D{}));
> +};
> +template <typename, typename, typename>
> +using I = F<int>;
> +template <typename K, typename V, typename H = K>
> +using J = I<K, V, H>;
> +struct K {
> +  typedef J<long, char> L;
> +  L k;
> +  K();
> +};
> +struct M {
> +  bool bar () const;
> +  K::L m;
> +};
> +K n;
> +bool M::bar () const { n.k = m; return true; }
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept86.C b/gcc/testsuite/g++.dg/cpp0x/noexcept86.C
> new file mode 100644
> index 00000000000..2d040c090f5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept86.C
> @@ -0,0 +1,25 @@
> +// PR c++/114349
> +// { dg-do compile { target c++14 } }
> +
> +struct B
> +{
> +  int i;
> +};
> +
> +template <bool BA>
> +void
> +goo ()
> +{
> +  constexpr bool is_yes = BA;
> +  struct C
> +  {
> +    static auto g(B b) noexcept(is_yes) { }
> +  };
> +  C::g({});
> +}
> +
> +void
> +x ()
> +{
> +  goo<false>();
> +}
> 
> base-commit: 65b7d1862e11784a0ce67ab758e06dd8aa65b181
diff mbox series

Patch

diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index dce4caf8981..4b2b27bdd0d 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -8664,10 +8664,14 @@  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);
+  const bool push_to_top
+    = (LAMBDA_FUNCTION_P (d)
+       || (TREE_CODE (d) == TYPE_DECL
+	   && TREE_TYPE (d)
+	   && LAMBDA_TYPE_P (TREE_TYPE (d)))
+       || !current_function_decl
+       || (!decl_function_context (d)
+	   && decl_function_context (d) != current_function_decl));
 
   if (push_to_top)
     push_to_top_level ();
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 8cf0d5b7a8d..7b00a8615d2 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -26855,7 +26855,7 @@  maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 	}
       else if (push_tinst_level (fn))
 	{
-	  push_to_top_level ();
+	  const bool push_to_top = maybe_push_to_top_level (fn);
 	  push_access_scope (fn);
 	  push_deferring_access_checks (dk_no_deferred);
 	  input_location = DECL_SOURCE_LOCATION (fn);
@@ -26878,17 +26878,10 @@  maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 	  if (orig_fn)
 	    ++processing_template_decl;
 
-	  ++cp_unevaluated_operand;
-	  ++c_inhibit_evaluation_warnings;
-	  ++cp_noexcept_operand;
 	  /* Do deferred instantiation of the noexcept-specifier.  */
 	  noex = tsubst_expr (DEFERRED_NOEXCEPT_PATTERN (noex),
 			      DEFERRED_NOEXCEPT_ARGS (noex),
 			      tf_warning_or_error, fn);
-	  --cp_unevaluated_operand;
-	  --c_inhibit_evaluation_warnings;
-	  --cp_noexcept_operand;
-
 	  /* Build up the noexcept-specification.  */
 	  spec = build_noexcept_spec (noex, tf_warning_or_error);
 
@@ -26898,7 +26891,7 @@  maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 	  pop_deferring_access_checks ();
 	  pop_access_scope (fn);
 	  pop_tinst_level ();
-	  pop_from_top_level ();
+	  maybe_pop_from_top_level (push_to_top);
 	}
       else
 	spec = noexcept_false_spec;
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept85.C b/gcc/testsuite/g++.dg/cpp0x/noexcept85.C
new file mode 100644
index 00000000000..b415bb46bc9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept85.C
@@ -0,0 +1,33 @@ 
+// PR c++/114349
+// { dg-do compile { target c++11 } }
+
+using A = struct {};
+template <template <typename> class, typename, typename>
+using B = A;
+template <typename T>
+using C = typename T::D;
+struct E {
+  using D = B<C, int, A>;
+};
+template <class> constexpr bool foo (A) { return false; }
+template <class T> struct F {
+  using G = T;
+  using H = E;
+  F(const F &);
+  void operator=(F) noexcept(foo <G> (H::D{}));
+};
+template <typename, typename, typename>
+using I = F<int>;
+template <typename K, typename V, typename H = K>
+using J = I<K, V, H>;
+struct K {
+  typedef J<long, char> L;
+  L k;
+  K();
+};
+struct M {
+  bool bar () const;
+  K::L m;
+};
+K n;
+bool M::bar () const { n.k = m; return true; }
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept86.C b/gcc/testsuite/g++.dg/cpp0x/noexcept86.C
new file mode 100644
index 00000000000..2d040c090f5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept86.C
@@ -0,0 +1,25 @@ 
+// PR c++/114349
+// { dg-do compile { target c++14 } }
+
+struct B
+{
+  int i;
+};
+
+template <bool BA>
+void
+goo ()
+{
+  constexpr bool is_yes = BA;
+  struct C
+  {
+    static auto g(B b) noexcept(is_yes) { }
+  };
+  C::g({});
+}
+
+void
+x ()
+{
+  goo<false>();
+}