c++: Don't synthesize sfk_comparison method multiple times [PR94907]

On the following testcase we ICE, because synthesize_method is called twice
on the same sfk_comparison method fndecl, the first time it works fine
because start_preparsed_function in that case sets both
current_function_decl and cfun, but second time it is called it only sets
the former and keeps cfun NULL, so we ICE when trying to store
current_function_returns_value.
I think it is just wrong to call synthesize_method multiple times, and most
synthesize_method callers avoid that by not calling it if DECL_INITIAL is
already set, so this patch does that too.

2020-05-06  Jakub Jelinek  <jakub@redhat.com>

	PR c++/94907
	* method.c (defaulted_late_check): Don't call synthesize_method
	on constexpr sfk_comparison if it has been called on it already.

	* g++.dg/cpp2a/spaceship-synth8.C: New test.
This commit is contained in:
Jakub Jelinek 2020-05-06 23:36:31 +02:00
parent 72a54e5e81
commit 25ee2155ea
4 changed files with 24 additions and 1 deletions

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@ -1,3 +1,9 @@
2020-05-06 Jakub Jelinek <jakub@redhat.com>
PR c++/94907
* method.c (defaulted_late_check): Don't call synthesize_method
on constexpr sfk_comparison if it has been called on it already.
2020-05-06 Nathan Sidwell <nathan@acm.org>
PR c++/94946

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@ -2939,7 +2939,7 @@ defaulted_late_check (tree fn)
{
/* If the function was declared constexpr, check that the definition
qualifies. Otherwise we can define the function lazily. */
if (DECL_DECLARED_CONSTEXPR_P (fn))
if (DECL_DECLARED_CONSTEXPR_P (fn) && !DECL_INITIAL (fn))
synthesize_method (fn);
return;
}

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@ -1,3 +1,8 @@
2020-05-06 Jakub Jelinek <jakub@redhat.com>
PR c++/94907
* g++.dg/cpp2a/spaceship-synth8.C: New test.
2020-05-06 qing zhao <qing.zhao@oracle.com>
PR c/94230

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@ -0,0 +1,12 @@
// PR c++/94907
// { dg-do compile { target c++2a } }
namespace std { struct strong_ordering { }; }
struct E;
struct D {
virtual std::strong_ordering operator<=>(const struct E&) const = 0;
};
struct E : D {
std::strong_ordering operator<=>(const E&) const override = default;
};