* [PATCH] c++: ICE with noexcept and local specialization [PR114114]
@ 2024-03-05 20:56 Marek Polacek
2024-03-05 23:20 ` Jason Merrill
2024-03-15 14:35 ` Patrick Palka
0 siblings, 2 replies; 6+ messages in thread
From: Marek Polacek @ 2024-03-05 20:56 UTC (permalink / raw)
To: GCC Patches, Jason Merrill
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Here we ICE because we call register_local_specialization while
local_specializations is null, so
local_specializations->put ();
crashes on null this. It's null since maybe_instantiate_noexcept calls
push_to_top_level which creates a new scope. Normally, I would have
guessed that we need a new local_specialization_stack. But here we're
dealing with an operand of a noexcept, which is an unevaluated operand,
and those aren't registered in the hash map. maybe_instantiate_noexcept
wasn't signalling that it's substituting an unevaluated operand though.
PR c++/114114
gcc/cp/ChangeLog:
* pt.cc (maybe_instantiate_noexcept): Save/restore
cp_unevaluated_operand, c_inhibit_evaluation_warnings, and
cp_noexcept_operand around the tsubst_expr call.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/noexcept84.C: New test.
---
gcc/cp/pt.cc | 6 +++++
gcc/testsuite/g++.dg/cpp0x/noexcept84.C | 32 +++++++++++++++++++++++++
2 files changed, 38 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept84.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index c4bc54a8fdb..11f7d33c766 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -26869,10 +26869,16 @@ 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);
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept84.C b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
new file mode 100644
index 00000000000..06f33264f77
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
@@ -0,0 +1,32 @@
+// PR c++/114114
+// { dg-do compile { target c++11 } }
+
+template<bool B>
+constexpr void
+test ()
+{
+ constexpr bool is_yes = B;
+ struct S {
+ constexpr S() noexcept(is_yes) { }
+ };
+ S s;
+}
+
+constexpr bool foo() { return true; }
+
+template<typename T>
+constexpr void
+test2 ()
+{
+ constexpr T (*pfn)() = &foo;
+ struct S {
+ constexpr S() noexcept(pfn()) { }
+ };
+ S s;
+}
+
+int main()
+{
+ test<true>();
+ test2<bool>();
+}
base-commit: 8776468d9e57ace5f832c1368243a6dbce9984d5
--
2.44.0
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] c++: ICE with noexcept and local specialization [PR114114]
2024-03-05 20:56 [PATCH] c++: ICE with noexcept and local specialization [PR114114] Marek Polacek
@ 2024-03-05 23:20 ` Jason Merrill
2024-03-15 14:35 ` Patrick Palka
1 sibling, 0 replies; 6+ messages in thread
From: Jason Merrill @ 2024-03-05 23:20 UTC (permalink / raw)
To: Marek Polacek, GCC Patches
On 3/5/24 15:56, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
> -- >8 --
> Here we ICE because we call register_local_specialization while
> local_specializations is null, so
>
> local_specializations->put ();
>
> crashes on null this. It's null since maybe_instantiate_noexcept calls
> push_to_top_level which creates a new scope. Normally, I would have
> guessed that we need a new local_specialization_stack. But here we're
> dealing with an operand of a noexcept, which is an unevaluated operand,
> and those aren't registered in the hash map. maybe_instantiate_noexcept
> wasn't signalling that it's substituting an unevaluated operand though.
>
> PR c++/114114
>
> gcc/cp/ChangeLog:
>
> * pt.cc (maybe_instantiate_noexcept): Save/restore
> cp_unevaluated_operand, c_inhibit_evaluation_warnings, and
> cp_noexcept_operand around the tsubst_expr call.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/noexcept84.C: New test.
> ---
> gcc/cp/pt.cc | 6 +++++
> gcc/testsuite/g++.dg/cpp0x/noexcept84.C | 32 +++++++++++++++++++++++++
> 2 files changed, 38 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept84.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index c4bc54a8fdb..11f7d33c766 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -26869,10 +26869,16 @@ 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);
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept84.C b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> new file mode 100644
> index 00000000000..06f33264f77
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> @@ -0,0 +1,32 @@
> +// PR c++/114114
> +// { dg-do compile { target c++11 } }
> +
> +template<bool B>
> +constexpr void
> +test ()
> +{
> + constexpr bool is_yes = B;
> + struct S {
> + constexpr S() noexcept(is_yes) { }
> + };
> + S s;
> +}
> +
> +constexpr bool foo() { return true; }
> +
> +template<typename T>
> +constexpr void
> +test2 ()
> +{
> + constexpr T (*pfn)() = &foo;
> + struct S {
> + constexpr S() noexcept(pfn()) { }
> + };
> + S s;
> +}
> +
> +int main()
> +{
> + test<true>();
> + test2<bool>();
> +}
>
> base-commit: 8776468d9e57ace5f832c1368243a6dbce9984d5
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] c++: ICE with noexcept and local specialization [PR114114]
2024-03-05 20:56 [PATCH] c++: ICE with noexcept and local specialization [PR114114] Marek Polacek
2024-03-05 23:20 ` Jason Merrill
@ 2024-03-15 14:35 ` Patrick Palka
2024-03-15 15:23 ` Marek Polacek
1 sibling, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2024-03-15 14:35 UTC (permalink / raw)
To: Marek Polacek; +Cc: GCC Patches, Jason Merrill
On Tue, 5 Mar 2024, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>
> -- >8 --
> Here we ICE because we call register_local_specialization while
> local_specializations is null, so
>
> local_specializations->put ();
>
> crashes on null this. It's null since maybe_instantiate_noexcept calls
> push_to_top_level which creates a new scope. Normally, I would have
> guessed that we need a new local_specialization_stack. But here we're
> dealing with an operand of a noexcept, which is an unevaluated operand,
> and those aren't registered in the hash map. maybe_instantiate_noexcept
> wasn't signalling that it's substituting an unevaluated operand though.
It thought it was noexcept-exprs rather than noexcept-specs that are
unevaluated contexts?
>
> PR c++/114114
>
> gcc/cp/ChangeLog:
>
> * pt.cc (maybe_instantiate_noexcept): Save/restore
> cp_unevaluated_operand, c_inhibit_evaluation_warnings, and
> cp_noexcept_operand around the tsubst_expr call.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/noexcept84.C: New test.
> ---
> gcc/cp/pt.cc | 6 +++++
> gcc/testsuite/g++.dg/cpp0x/noexcept84.C | 32 +++++++++++++++++++++++++
> 2 files changed, 38 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept84.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index c4bc54a8fdb..11f7d33c766 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -26869,10 +26869,16 @@ 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);
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept84.C b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> new file mode 100644
> index 00000000000..06f33264f77
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> @@ -0,0 +1,32 @@
> +// PR c++/114114
> +// { dg-do compile { target c++11 } }
> +
> +template<bool B>
> +constexpr void
> +test ()
> +{
> + constexpr bool is_yes = B;
> + struct S {
> + constexpr S() noexcept(is_yes) { }
> + };
> + S s;
> +}
> +
> +constexpr bool foo() { return true; }
> +
> +template<typename T>
> +constexpr void
> +test2 ()
> +{
> + constexpr T (*pfn)() = &foo;
> + struct S {
> + constexpr S() noexcept(pfn()) { }
> + };
> + S s;
> +}
> +
> +int main()
> +{
> + test<true>();
> + test2<bool>();
> +}
>
> base-commit: 8776468d9e57ace5f832c1368243a6dbce9984d5
> --
> 2.44.0
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] c++: ICE with noexcept and local specialization [PR114114]
2024-03-15 14:35 ` Patrick Palka
@ 2024-03-15 15:23 ` Marek Polacek
2024-03-15 16:12 ` Patrick Palka
0 siblings, 1 reply; 6+ messages in thread
From: Marek Polacek @ 2024-03-15 15:23 UTC (permalink / raw)
To: Patrick Palka; +Cc: GCC Patches, Jason Merrill
On Fri, Mar 15, 2024 at 10:35:07AM -0400, Patrick Palka wrote:
> On Tue, 5 Mar 2024, Marek Polacek wrote:
>
> > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> >
> > -- >8 --
> > Here we ICE because we call register_local_specialization while
> > local_specializations is null, so
> >
> > local_specializations->put ();
> >
> > crashes on null this. It's null since maybe_instantiate_noexcept calls
> > push_to_top_level which creates a new scope. Normally, I would have
> > guessed that we need a new local_specialization_stack. But here we're
> > dealing with an operand of a noexcept, which is an unevaluated operand,
> > and those aren't registered in the hash map. maybe_instantiate_noexcept
> > wasn't signalling that it's substituting an unevaluated operand though.
>
> It thought it was noexcept-exprs rather than noexcept-specs that are
> unevaluated contexts?
Yes, sigh. It would have to be noexcept(noexcept(x)). I was looking at
cp_parser_unary_expression/RID_NOEXCEPT but that's a noexcept-expr. So
what can we do here, set a new local_specialization_stack? That wasn't
that straightforward when I tried. Or maybe just
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -15649,7 +15649,7 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain,
{
if (DECL_LANG_SPECIFIC (r))
DECL_TEMPLATE_INFO (r) = NULL_TREE;
- if (!cp_unevaluated_operand)
+ if (!cp_unevaluated_operand && local_specializations)
register_local_specialization (r, t);
}
?
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] c++: ICE with noexcept and local specialization [PR114114]
2024-03-15 15:23 ` Marek Polacek
@ 2024-03-15 16:12 ` Patrick Palka
2024-03-21 21:04 ` Marek Polacek
0 siblings, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2024-03-15 16:12 UTC (permalink / raw)
To: Marek Polacek; +Cc: Patrick Palka, GCC Patches, Jason Merrill
On Fri, 15 Mar 2024, Marek Polacek wrote:
> On Fri, Mar 15, 2024 at 10:35:07AM -0400, Patrick Palka wrote:
> > On Tue, 5 Mar 2024, Marek Polacek wrote:
> >
> > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > >
> > > -- >8 --
> > > Here we ICE because we call register_local_specialization while
> > > local_specializations is null, so
> > >
> > > local_specializations->put ();
> > >
> > > crashes on null this. It's null since maybe_instantiate_noexcept calls
> > > push_to_top_level which creates a new scope. Normally, I would have
> > > guessed that we need a new local_specialization_stack. But here we're
> > > dealing with an operand of a noexcept, which is an unevaluated operand,
> > > and those aren't registered in the hash map. maybe_instantiate_noexcept
> > > wasn't signalling that it's substituting an unevaluated operand though.
> >
> > It thought it was noexcept-exprs rather than noexcept-specs that are
> > unevaluated contexts?
>
> Yes, sigh. It would have to be noexcept(noexcept(x)). I was looking at
> cp_parser_unary_expression/RID_NOEXCEPT but that's a noexcept-expr. So
> what can we do here, set a new local_specialization_stack? That wasn't
> that straightforward when I tried. Or maybe just
Maybe we can avoid doing push_to_top_level (which clears
local_specializations) from maybe_instantiate_noexcept if
current_function_decl == fn?
Relatedly I wonder if we can avoid calling regenerate_decl_from_template
for local class member functions since they can't be redeclared?
>
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -15649,7 +15649,7 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain,
> {
> if (DECL_LANG_SPECIFIC (r))
> DECL_TEMPLATE_INFO (r) = NULL_TREE;
> - if (!cp_unevaluated_operand)
> + if (!cp_unevaluated_operand && local_specializations)
> register_local_specialization (r, t);
> }
>
> ?
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] c++: ICE with noexcept and local specialization [PR114114]
2024-03-15 16:12 ` Patrick Palka
@ 2024-03-21 21:04 ` Marek Polacek
0 siblings, 0 replies; 6+ messages in thread
From: Marek Polacek @ 2024-03-21 21:04 UTC (permalink / raw)
To: Patrick Palka; +Cc: GCC Patches, Jason Merrill
On Fri, Mar 15, 2024 at 12:12:49PM -0400, Patrick Palka wrote:
> On Fri, 15 Mar 2024, Marek Polacek wrote:
>
> > On Fri, Mar 15, 2024 at 10:35:07AM -0400, Patrick Palka wrote:
> > > On Tue, 5 Mar 2024, Marek Polacek wrote:
> > >
> > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > > >
> > > > -- >8 --
> > > > Here we ICE because we call register_local_specialization while
> > > > local_specializations is null, so
> > > >
> > > > local_specializations->put ();
> > > >
> > > > crashes on null this. It's null since maybe_instantiate_noexcept calls
> > > > push_to_top_level which creates a new scope. Normally, I would have
> > > > guessed that we need a new local_specialization_stack. But here we're
> > > > dealing with an operand of a noexcept, which is an unevaluated operand,
> > > > and those aren't registered in the hash map. maybe_instantiate_noexcept
> > > > wasn't signalling that it's substituting an unevaluated operand though.
> > >
> > > It thought it was noexcept-exprs rather than noexcept-specs that are
> > > unevaluated contexts?
> >
> > Yes, sigh. It would have to be noexcept(noexcept(x)). I was looking at
> > cp_parser_unary_expression/RID_NOEXCEPT but that's a noexcept-expr. So
> > what can we do here, set a new local_specialization_stack? That wasn't
> > that straightforward when I tried. Or maybe just
>
> Maybe we can avoid doing push_to_top_level (which clears
> local_specializations) from maybe_instantiate_noexcept if
> current_function_decl == fn?
Thanks, I agree that not doing push_to_top_level in the first place
is a better fix. I just sent a patch that does that.
> Relatedly I wonder if we can avoid calling regenerate_decl_from_template
> for local class member functions since they can't be redeclared?
Good point. I've tried the below, but that breaks a lot of contracts tests.
I have not pursued it further than that.
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index a7ba8b5af92..5352453a5d3 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -26623,6 +26623,12 @@ regenerate_decl_from_template (tree decl, tree tmpl, tree args)
if (DECL_UNIQUE_FRIEND_P (decl))
goto done;
+ /* [class.mem.general]/5 says that a member shall not be declared twice
+ in the member-specification (unless it's a nested class or member class
+ template or an enumeration). */
+ if (DECL_CLASS_SCOPE_P (decl))
+ goto done;
+
/* Use the source location of the definition. */
DECL_SOURCE_LOCATION (decl) = DECL_SOURCE_LOCATION (tmpl);
Marek
^ permalink raw reply [flat|nested] 6+ messages in thread
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2024-03-05 20:56 [PATCH] c++: ICE with noexcept and local specialization [PR114114] Marek Polacek
2024-03-05 23:20 ` Jason Merrill
2024-03-15 14:35 ` Patrick Palka
2024-03-15 15:23 ` Marek Polacek
2024-03-15 16:12 ` Patrick Palka
2024-03-21 21:04 ` Marek Polacek
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