[PATCH] c++: Lost deprecated/unavailable attr in class tmpl [PR104682]
Iain Sandoe
iain@sandoe.co.uk
Mon Feb 28 16:30:01 GMT 2022
> On 28 Feb 2022, at 16:13, Jason Merrill <jason@redhat.com> wrote:
>
> On 2/25/22 17:59, Marek Polacek wrote:
>> [ Most likely a GCC 13 patch, but I'm posting it now so that I don't lose it. ]
>> When looking into the other PR I noticed that we fail to give a warning
>> for a deprecated enumerator when the enum is in a class template. This
>> only happens when the attribute doesn't have an argument. The reason is
>> that when we tsubst_enum, we create a new enumerator:
>> build_enumerator (DECL_NAME (decl), value, newtag,
>> DECL_ATTRIBUTES (decl), DECL_SOURCE_LOCATION (decl));
>> but DECL_ATTRIBUTES (decl) is null when the attribute was provided
>> without an argument -- in that case it simply melts into a tree flag.
>> handle_deprecated_attribute has:
>> if (!args)
>> *no_add_attrs = true;
>> so the attribute isn't retained and we lose it when tsubsting. Same
>> thing when the attribute is on the enum itself.
>> Attribute unavailable is a similar case, but it's different in that
>> it can be a late attribute whereas "deprecated" can't:
>
> Iain, was this difference intentional?
The intent was to treat the two attributes the same way - so any difference
is unintentional.
Iain
>
>> is_late_template_attribute has
>> /* But some attributes specifically apply to templates. */
>> && !is_attribute_p ("abi_tag", name)
>> && !is_attribute_p ("deprecated", name)
>> && !is_attribute_p ("visibility", name))
>> return true;
>> else
>> return false;
>> which looks strange, but attr-unavailable-9.C tests that we don't error when
>> the attribute is applied on a template.
>> Bootstrapped/regtested on x86_64-pc-linux-gnu.
>
> This looks extremely safe, so let's go ahead and apply it to trunk.
>
>> PR c++/104682
>> gcc/cp/ChangeLog:
>> * cp-tree.h (build_enumerator): Adjust.
>> * decl.cc (finish_enum): Make it return the new decl.
>> * pt.cc (tsubst_enum): Propagate TREE_DEPRECATED and TREE_UNAVAILABLE.
>> gcc/testsuite/ChangeLog:
>> * g++.dg/ext/attr-unavailable-10.C: New test.
>> * g++.dg/ext/attr-unavailable-11.C: New test.
>> * g++.dg/warn/deprecated-17.C: New test.
>> * g++.dg/warn/deprecated-18.C: New test.
>> ---
>> gcc/cp/cp-tree.h | 2 +-
>> gcc/cp/decl.cc | 4 +-
>> gcc/cp/pt.cc | 17 +++++++--
>> .../g++.dg/ext/attr-unavailable-10.C | 22 +++++++++++
>> .../g++.dg/ext/attr-unavailable-11.C | 22 +++++++++++
>> gcc/testsuite/g++.dg/warn/deprecated-17.C | 35 ++++++++++++++++++
>> gcc/testsuite/g++.dg/warn/deprecated-18.C | 37 +++++++++++++++++++
>> 7 files changed, 133 insertions(+), 6 deletions(-)
>> create mode 100644 gcc/testsuite/g++.dg/ext/attr-unavailable-10.C
>> create mode 100644 gcc/testsuite/g++.dg/ext/attr-unavailable-11.C
>> create mode 100644 gcc/testsuite/g++.dg/warn/deprecated-17.C
>> create mode 100644 gcc/testsuite/g++.dg/warn/deprecated-18.C
>> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
>> index 37d462fca6e..80994e94793 100644
>> --- a/gcc/cp/cp-tree.h
>> +++ b/gcc/cp/cp-tree.h
>> @@ -6833,7 +6833,7 @@ extern void xref_basetypes (tree, tree);
>> extern tree start_enum (tree, tree, tree, tree, bool, bool *);
>> extern void finish_enum_value_list (tree);
>> extern void finish_enum (tree);
>> -extern void build_enumerator (tree, tree, tree, tree, location_t);
>> +extern tree build_enumerator (tree, tree, tree, tree, location_t);
>> extern tree lookup_enumerator (tree, tree);
>> extern bool start_preparsed_function (tree, tree, int);
>> extern bool start_function (cp_decl_specifier_seq *,
>> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
>> index 7b48b56231b..7f80f9d4d7a 100644
>> --- a/gcc/cp/decl.cc
>> +++ b/gcc/cp/decl.cc
>> @@ -16409,7 +16409,7 @@ finish_enum (tree enumtype)
>> Apply ATTRIBUTES if available. LOC is the location of NAME.
>> Assignment of sequential values by default is handled here. */
>> -void
>> +tree
>> build_enumerator (tree name, tree value, tree enumtype, tree attributes,
>> location_t loc)
>> {
>> @@ -16611,6 +16611,8 @@ incremented enumerator value is too large for %<long%>"));
>> /* Add this enumeration constant to the list for this type. */
>> TYPE_VALUES (enumtype) = tree_cons (name, decl, TYPE_VALUES (enumtype));
>> +
>> + return decl;
>> }
>> /* Look for an enumerator with the given NAME within the enumeration
>> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
>> index 70f02db8757..8fb17349ee1 100644
>> --- a/gcc/cp/pt.cc
>> +++ b/gcc/cp/pt.cc
>> @@ -26944,9 +26944,8 @@ tsubst_enum (tree tag, tree newtag, tree args)
>> for (e = TYPE_VALUES (tag); e; e = TREE_CHAIN (e))
>> {
>> tree value;
>> - tree decl;
>> + tree decl = TREE_VALUE (e);
>> - decl = TREE_VALUE (e);
>> /* Note that in a template enum, the TREE_VALUE is the
>> CONST_DECL, not the corresponding INTEGER_CST. */
>> value = tsubst_expr (DECL_INITIAL (decl),
>> @@ -26958,8 +26957,14 @@ tsubst_enum (tree tag, tree newtag, tree args)
>> /* Actually build the enumerator itself. Here we're assuming that
>> enumerators can't have dependent attributes. */
>> - build_enumerator (DECL_NAME (decl), value, newtag,
>> - DECL_ATTRIBUTES (decl), DECL_SOURCE_LOCATION (decl));
>> + tree newdecl = build_enumerator (DECL_NAME (decl), value, newtag,
>> + DECL_ATTRIBUTES (decl),
>> + DECL_SOURCE_LOCATION (decl));
>> + /* Attribute deprecated without an argument isn't sticky: it'll
>> + melt into a tree flag, so we need to propagate the flag here,
>> + since we just created a new enumerator. */
>> + TREE_DEPRECATED (newdecl) = TREE_DEPRECATED (decl);
>> + TREE_UNAVAILABLE (newdecl) = TREE_UNAVAILABLE (decl);
>> }
>> if (SCOPED_ENUM_P (newtag))
>> @@ -26970,6 +26975,10 @@ tsubst_enum (tree tag, tree newtag, tree args)
>> DECL_SOURCE_LOCATION (TYPE_NAME (newtag))
>> = DECL_SOURCE_LOCATION (TYPE_NAME (tag));
>> + TREE_DEPRECATED (newtag) = TREE_DEPRECATED (tag);
>> + /* We don't need to propagate TREE_UNAVAILABLE here, because it is, unlike
>> + deprecated, applied at instantiation time rather than template
>> + definition time. */
>> }
>> /* DECL is a FUNCTION_DECL that is a template specialization. Return
>> diff --git a/gcc/testsuite/g++.dg/ext/attr-unavailable-10.C b/gcc/testsuite/g++.dg/ext/attr-unavailable-10.C
>> new file mode 100644
>> index 00000000000..cfb99476b9f
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/ext/attr-unavailable-10.C
>> @@ -0,0 +1,22 @@
>> +// PR c++/104682
>> +// { dg-do compile { target c++11 } }
>> +
>> +template<typename>
>> +struct S {
>> + enum E1 {
>> + A __attribute__((unavailable))
>> + };
>> +};
>> +
>> +struct S2 {
>> + enum E2 {
>> + A __attribute__((unavailable))
>> + };
>> +};
>> +
>> +void
>> +g ()
>> +{
>> + auto a1 = S<int>::E1::A; // { dg-error "is unavailable" }
>> + auto b1 = S2::E2::A; // { dg-error "is unavailable" }
>> +}
>> diff --git a/gcc/testsuite/g++.dg/ext/attr-unavailable-11.C b/gcc/testsuite/g++.dg/ext/attr-unavailable-11.C
>> new file mode 100644
>> index 00000000000..fce24528908
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/ext/attr-unavailable-11.C
>> @@ -0,0 +1,22 @@
>> +// PR c++/104682
>> +// { dg-do compile { target c++11 } }
>> +
>> +template<typename>
>> +struct S {
>> + enum B {
>> + A
>> + } __attribute__((unavailable)) ;
>> +};
>> +
>> +struct S2 {
>> + enum B {
>> + A
>> + } __attribute__((unavailable));
>> +};
>> +
>> +void
>> +g ()
>> +{
>> + S<int>::B a1; // { dg-error "is unavailable" }
>> + S2::B a2; // { dg-error "is unavailable" }
>> +}
>> diff --git a/gcc/testsuite/g++.dg/warn/deprecated-17.C b/gcc/testsuite/g++.dg/warn/deprecated-17.C
>> new file mode 100644
>> index 00000000000..c4e768538fa
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/warn/deprecated-17.C
>> @@ -0,0 +1,35 @@
>> +// PR c++/104682
>> +// { dg-do compile { target c++11 } }
>> +
>> +template<typename>
>> +struct S {
>> + enum E1 {
>> + A __attribute__((deprecated)),
>> + B __attribute__((deprecated("B"))),
>> + C [[deprecated]],
>> + D [[deprecated("D")]]
>> + };
>> +};
>> +
>> +struct S2 {
>> + enum E2 {
>> + A __attribute__((deprecated)),
>> + B __attribute__((deprecated("B"))),
>> + C [[deprecated]],
>> + D [[deprecated("D")]]
>> + };
>> +};
>> +
>> +void
>> +g ()
>> +{
>> + auto a1 = S<int>::E1::A; // { dg-warning "is deprecated" }
>> + auto a2 = S<int>::E1::B; // { dg-warning "is deprecated" }
>> + auto a3 = S<int>::E1::C; // { dg-warning "is deprecated" }
>> + auto a4 = S<int>::E1::D; // { dg-warning "is deprecated" }
>> +
>> + auto b1 = S2::A; // { dg-warning "is deprecated" }
>> + auto b2 = S2::B; // { dg-warning "is deprecated" }
>> + auto b3 = S2::C; // { dg-warning "is deprecated" }
>> + auto b4 = S2::D; // { dg-warning "is deprecated" }
>> +}
>> diff --git a/gcc/testsuite/g++.dg/warn/deprecated-18.C b/gcc/testsuite/g++.dg/warn/deprecated-18.C
>> new file mode 100644
>> index 00000000000..0d101a9cc90
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/warn/deprecated-18.C
>> @@ -0,0 +1,37 @@
>> +// PR c++/104682
>> +// { dg-do compile { target c++11 } }
>> +
>> +template<typename>
>> +struct S {
>> + enum B {
>> + A
>> + } __attribute__((deprecated)) ;
>> +};
>> +
>> +struct S2 {
>> + enum B {
>> + A
>> + } __attribute__((deprecated));
>> +};
>> +
>> +template<typename>
>> +struct S3 {
>> + enum [[deprecated]] B {
>> + A
>> + };
>> +};
>> +
>> +struct S4 {
>> + enum [[deprecated]] B {
>> + A
>> + };
>> +};
>> +
>> +void
>> +g ()
>> +{
>> + S<int>::B a1; // { dg-warning "is deprecated" }
>> + S2::B a2; // { dg-warning "is deprecated" }
>> + S3<int>::B a3; // { dg-warning "is deprecated" }
>> + S4::B a4; // { dg-warning "is deprecated" }
>> +}
>> base-commit: f62115c9b770a66c5378f78a2d5866243d560573
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