Currently __has_attribute(init_priority) always returns true, even on targets that don't actually support init priorities, and when using the attribute on such targets, we issue a hard error that init priorities are unsupported. This makes it impossible to conditionally use the attribute by querying __has_attribute.
This patch fixes this by adding the attribute to the attribute table only if the target supports init priorities, so that __has_attribute returns false appropriately. Thus on such targets we'll now treat it as just another unrecognized attribute, so using it gives a -Wattribute warning instead of an error. gcc/cp/ChangeLog: * tree.cc (cxx_attribute_table): Add entry for init_priority only if SUPPORTS_INIT_PRIORITY. (handle_init_priority_attribute): Assert SUPPORTS_INIT_PRIORITY is true. gcc/testsuite/ChangeLog: * g++.dg/special/initpri3.C: New test. --- gcc/cp/tree.cc | 20 +++++++------------- gcc/testsuite/g++.dg/special/initpri3.C | 9 +++++++++ 2 files changed, 16 insertions(+), 13 deletions(-) create mode 100644 gcc/testsuite/g++.dg/special/initpri3.C diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc index 45348c58bb6..c30bbeb0839 100644 --- a/gcc/cp/tree.cc +++ b/gcc/cp/tree.cc @@ -5010,8 +5010,10 @@ const struct attribute_spec cxx_attribute_table[] = { /* { name, min_len, max_len, decl_req, type_req, fn_type_req, affects_type_identity, handler, exclude } */ +#if SUPPORTS_INIT_PRIORITY { "init_priority", 1, 1, true, false, false, false, handle_init_priority_attribute, NULL }, +#endif { "abi_tag", 1, -1, false, false, false, true, handle_abi_tag_attribute, NULL }, { NULL, 0, 0, false, false, false, false, NULL, NULL } @@ -5039,7 +5041,7 @@ const struct attribute_spec std_attribute_table[] = /* Handle an "init_priority" attribute; arguments as in struct attribute_spec.handler. */ -static tree +ATTRIBUTE_UNUSED static tree handle_init_priority_attribute (tree* node, tree name, tree args, @@ -5103,18 +5105,10 @@ handle_init_priority_attribute (tree* node, pri); } - if (SUPPORTS_INIT_PRIORITY) - { - SET_DECL_INIT_PRIORITY (decl, pri); - DECL_HAS_INIT_PRIORITY_P (decl) = 1; - return NULL_TREE; - } - else - { - error ("%qE attribute is not supported on this platform", name); - *no_add_attrs = true; - return NULL_TREE; - } + gcc_assert (SUPPORTS_INIT_PRIORITY); + SET_DECL_INIT_PRIORITY (decl, pri); + DECL_HAS_INIT_PRIORITY_P (decl) = 1; + return NULL_TREE; } /* DECL is being redeclared; the old declaration had the abi tags in OLD, diff --git a/gcc/testsuite/g++.dg/special/initpri3.C b/gcc/testsuite/g++.dg/special/initpri3.C new file mode 100644 index 00000000000..a181abdd0b1 --- /dev/null +++ b/gcc/testsuite/g++.dg/special/initpri3.C @@ -0,0 +1,9 @@ +// Verify __has_attribute(init_priority) is false whenever the platform +// doesn't support it, and is treated as an unrecognized attribute. + +#if !__has_attribute(init_priority) +#error init_priority /* { dg-error "" "" { target { ! init_priority } } } */ +#endif + +struct A { A(); } a __attribute__((init_priority(500))); +// { dg-warning "attribute directive ignored" "" { target { ! init_priority } } .-1 } -- 2.38.1.385.g3b08839926