c++/modules: Fix linkage checks for exported using-decls
This fixes some inconsistencies with what kinds of linkage various entities are assumed to have. This also fixes handling of exported using-decls binding to GM entities and type aliases to better align with the standard's requirements. gcc/cp/ChangeLog: * name-lookup.cc (check_can_export_using_decl): Handle internal linkage GM entities (but ignore in header units); use linkage of entity ultimately referred to by aliases. gcc/testsuite/ChangeLog: * g++.dg/modules/using-10.C: Add tests for no-linkage, fix expected linkage of aliases. * g++.dg/modules/using-12.C: Likewise. * g++.dg/modules/using-27.C: New test. * g++.dg/modules/using-28_a.C: New test. * g++.dg/modules/using-28_b.C: New test. * g++.dg/modules/using-29.H: New test. Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com> Reviewed-by: Jason Merrill <jason@redhat.com>
This commit is contained in:
Nathaniel Shead
parent
ad08ef098a
commit
d0762e93ce
7 changed files with 159 additions and 46 deletions
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@ -5206,38 +5206,47 @@ pushdecl_outermost_localscope (tree x)
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static bool
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check_can_export_using_decl (tree binding)
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{
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tree decl = STRIP_TEMPLATE (binding);
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/* Declarations in header units are always OK. */
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if (header_module_p ())
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return true;
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/* Linkage is determined by the owner of an enumerator. */
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if (TREE_CODE (decl) == CONST_DECL)
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decl = TYPE_NAME (DECL_CONTEXT (decl));
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/* If the using decl is exported, the things it refers
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to must also be exported (or not have module attachment). */
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if (!DECL_MODULE_EXPORT_P (decl)
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&& (DECL_LANG_SPECIFIC (decl)
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&& DECL_MODULE_ATTACH_P (decl)))
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/* We want the linkage of the underlying entity, so strip typedefs.
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If the underlying entity is a builtin type then we're OK. */
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tree entity = binding;
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if (TREE_CODE (entity) == TYPE_DECL)
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{
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bool internal_p = !TREE_PUBLIC (decl);
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entity = TYPE_MAIN_DECL (TREE_TYPE (entity));
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if (!entity)
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return true;
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}
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/* A template in an anonymous namespace doesn't constrain TREE_PUBLIC
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until it's instantiated, so double-check its context. */
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if (!internal_p && TREE_CODE (binding) == TEMPLATE_DECL)
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internal_p = decl_internal_context_p (decl);
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linkage_kind linkage = decl_linkage (entity);
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tree not_tmpl = STRIP_TEMPLATE (entity);
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/* Attachment is determined by the owner of an enumerator. */
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if (TREE_CODE (not_tmpl) == CONST_DECL)
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not_tmpl = TYPE_NAME (DECL_CONTEXT (not_tmpl));
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/* If the using decl is exported, the things it refers to must
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have external linkage. decl_linkage returns lk_external for
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module linkage so also check for attachment. */
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if (linkage != lk_external
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|| (DECL_LANG_SPECIFIC (not_tmpl)
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&& DECL_MODULE_ATTACH_P (not_tmpl)
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&& !DECL_MODULE_EXPORT_P (not_tmpl)))
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{
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auto_diagnostic_group d;
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error ("exporting %q#D that does not have external linkage",
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binding);
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if (TREE_CODE (decl) == TYPE_DECL && !DECL_IMPLICIT_TYPEDEF_P (decl))
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/* An un-exported explicit type alias has no linkage. */
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inform (DECL_SOURCE_LOCATION (binding),
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"%q#D declared here with no linkage", binding);
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else if (internal_p)
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inform (DECL_SOURCE_LOCATION (binding),
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"%q#D declared here with internal linkage", binding);
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if (linkage == lk_none)
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inform (DECL_SOURCE_LOCATION (entity),
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"%q#D declared here with no linkage", entity);
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else if (linkage == lk_internal)
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inform (DECL_SOURCE_LOCATION (entity),
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"%q#D declared here with internal linkage", entity);
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else
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inform (DECL_SOURCE_LOCATION (binding),
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"%q#D declared here with module linkage", binding);
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inform (DECL_SOURCE_LOCATION (entity),
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"%q#D declared here with module linkage", entity);
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return false;
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}
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@ -23,6 +23,13 @@ namespace s {
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}
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}
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export using s::a1; // { dg-error "does not have external linkage" }
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export using s::b1; // { dg-error "does not have external linkage" }
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export using s::x1; // { dg-error "does not have external linkage" }
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export using s::y1; // { dg-error "does not have external linkage" }
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export using s::f1; // { dg-error "does not have external linkage" }
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export using s::g1; // { dg-error "does not have external linkage" }
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// module linkage
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namespace m {
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struct a2 {}; // { dg-message "declared here with module linkage" }
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@ -41,13 +48,6 @@ namespace m {
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void g2(); // { dg-message "declared here with module linkage" }
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}
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export using s::a1; // { dg-error "does not have external linkage" }
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export using s::b1; // { dg-error "does not have external linkage" }
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export using s::x1; // { dg-error "does not have external linkage" }
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export using s::y1; // { dg-error "does not have external linkage" }
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export using s::f1; // { dg-error "does not have external linkage" }
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export using s::g1; // { dg-error "does not have external linkage" }
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export using m::a2; // { dg-error "does not have external linkage" }
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export using m::b2; // { dg-error "does not have external linkage" }
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export using m::x2; // { dg-error "does not have external linkage" }
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@ -55,15 +55,47 @@ export using m::y2; // { dg-error "does not have external linkage" }
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export using m::f2; // { dg-error "does not have external linkage" }
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export using m::g2; // { dg-error "does not have external linkage" }
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namespace t {
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using a = int; // { dg-message "declared here with no linkage" }
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// no linkage
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namespace n {
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using a3 = struct { int x; }; // { dg-message "declared here with no linkage" }
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template <typename T>
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using b = int; // { dg-message "declared here with no linkage" }
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struct {} tmp_s; // { dg-message "declared here with no linkage" }
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using b3 = decltype(tmp_s);
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typedef int c; // { dg-message "declared here with no linkage" }
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enum {} tmp_e; // { dg-message "declared here with no linkage" }
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using c3 = decltype(tmp_e);
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auto foo() {
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struct s {}; // { dg-message "declared here with no linkage" }
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return s{};
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}
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using d3 = decltype(foo());
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}
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export using t::a; // { dg-error "does not have external linkage" }
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export using t::b; // { dg-error "does not have external linkage" }
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export using n::a3; // { dg-error "does not have external linkage" }
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export using n::b3; // { dg-error "does not have external linkage" }
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export using n::c3; // { dg-error "does not have external linkage" }
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export using n::d3; // { dg-error "does not have external linkage" }
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// typedefs
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namespace t {
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// aliases have the linkage of the entity they ultimately refer to
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using a = int;
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typedef a b;
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// a template is not an alias
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template <typename T>
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using c = int; // { dg-message "declared here with module linkage" }
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// anonymous type with typedef name for linkage purposes
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typedef struct {} d; // { dg-message "declared here with module linkage" }
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// non-empty enum gets linkage of enumerator name
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enum { X } e; // { dg-message "declared here with module linkage"}
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}
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export using t::a;
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export using t::b;
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export using t::c; // { dg-error "does not have external linkage" }
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export using t::d; // { dg-error "does not have external linkage" }
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export using t::e; // { dg-error "does not have external linkage" }
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@ -57,15 +57,47 @@ namespace m {
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export using m::g2; // { dg-error "does not have external linkage" }
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}
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namespace t {
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using a = int; // { dg-message "declared here with no linkage" }
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// no linkage
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namespace n {
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using a3 = struct { int x; }; // { dg-message "declared here with no linkage" }
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template <typename T>
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using b = int; // { dg-message "declared here with no linkage" }
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struct {} tmp_s; // { dg-message "declared here with no linkage" }
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using b3 = decltype(tmp_s);
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typedef int c; // { dg-message "declared here with no linkage" }
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enum {} tmp_e; // { dg-message "declared here with no linkage" }
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using c3 = decltype(tmp_e);
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export using t::a; // { dg-error "does not have external linkage" }
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export using t::b; // { dg-error "does not have external linkage" }
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export using t::c; // { dg-error "does not have external linkage" }
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auto foo() {
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struct s {}; // { dg-message "declared here with no linkage" }
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return s{};
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}
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using d3 = decltype(foo());
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export using n::a3; // { dg-error "does not have external linkage" }
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export using n::b3; // { dg-error "does not have external linkage" }
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export using n::c3; // { dg-error "does not have external linkage" }
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export using n::d3; // { dg-error "does not have external linkage" }
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}
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// typedefs
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namespace t {
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// aliases have the linkage of the entity they ultimately refer to
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using a = int;
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typedef a b;
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// a template is not an alias
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template <typename T>
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using c = int; // { dg-message "declared here with module linkage" }
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// anonymous type with typedef name for linkage purposes
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typedef struct {} d; // { dg-message "declared here with module linkage" }
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// non-empty enum gets linkage of enumerator name
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enum { X } e; // { dg-message "declared here with module linkage" }
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export using t::a;
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export using t::b;
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export using t::c; // { dg-error "does not have external linkage" }
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export using t::d; // { dg-error "does not have external linkage" }
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export using t::e; // { dg-error "does not have external linkage" }
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}
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14
gcc/testsuite/g++.dg/modules/using-27.C
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14
gcc/testsuite/g++.dg/modules/using-27.C
Normal file
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@ -0,0 +1,14 @@
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// { dg-additional-options "-fmodules-ts -Wno-global-module" }
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// { dg-module-cmi !bad }
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module;
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static int x = 123; // { dg-message "declared here with internal linkage" }
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static void f() {} // { dg-message "declared here with internal linkage" }
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using T = struct {}; // { dg-message "declared here with no linkage" }
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export module bad;
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export using ::x; // { dg-error "does not have external linkage" }
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export using ::f; // { dg-error "does not have external linkage" }
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export using ::T; // { dg-error "does not have external linkage" }
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12
gcc/testsuite/g++.dg/modules/using-28_a.C
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12
gcc/testsuite/g++.dg/modules/using-28_a.C
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@ -0,0 +1,12 @@
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// { dg-additional-options "-fmodules-ts -Wno-global-module" }
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// { dg-module-cmi M }
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// Test that typedef names correctly provide external linkage
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module;
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typedef struct { int x; } A;
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export module M;
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export typedef struct {} B;
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export using ::A;
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export using ::B;
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8
gcc/testsuite/g++.dg/modules/using-28_b.C
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8
gcc/testsuite/g++.dg/modules/using-28_b.C
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@ -0,0 +1,8 @@
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// { dg-additional-options "-fmodules-ts" }
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import M;
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int main() {
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A a { 10 };
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B b;
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}
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6
gcc/testsuite/g++.dg/modules/using-29.H
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6
gcc/testsuite/g++.dg/modules/using-29.H
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@ -0,0 +1,6 @@
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// { dg-additional-options "-fmodule-header" }
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static int foo = 123;
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namespace ns {
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using ::foo; // OK, we're in a header unit
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}
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