https://gcc.gnu.org/g:cf9efe5ec14fea3ad5746fbefb22544bb9424d9d
commit r15-3937-gcf9efe5ec14fea3ad5746fbefb22544bb9424d9d
Author: Nathaniel Shead <nathanielosh...@gmail.com>
Date: Fri Sep 27 18:58:27 2024 +1000
c++/modules: Propagate purview/import for templates in duplicate_decls
[PR116803]
We need to ensure that for a declaration in the module purview, that the
resulting declaration has PURVIEW_P set and IMPORT_P cleared so that we
understand it might be something requiring exporting. This is normally
handled for a declaration by set_instantiating_module, but when this
declaration is a redeclaration duplicate_decls needs to propagate this
to olddecl.
This patch only changes the logic for template declarations, because in
the non-template case the whole contents of olddecl's DECL_LANG_SPECIFIC
is replaced with newdecl's (which includes these flags), so there's
nothing to do.
PR c++/116803
gcc/cp/ChangeLog:
* decl.cc (duplicate_decls): Propagate DECL_MODULE_PURVIEW_P and
DECL_MODULE_IMPORT_P for template redeclarations.
gcc/testsuite/ChangeLog:
* g++.dg/modules/merge-18_a.H: New test.
* g++.dg/modules/merge-18_b.H: New test.
* g++.dg/modules/merge-18_c.C: New test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
Reviewed-by: Jason Merrill <ja...@redhat.com>
Diff:
---
gcc/cp/decl.cc | 10 ++++++++++
gcc/testsuite/g++.dg/modules/merge-18_a.H | 8 ++++++++
gcc/testsuite/g++.dg/modules/merge-18_b.H | 13 +++++++++++++
gcc/testsuite/g++.dg/modules/merge-18_c.C | 10 ++++++++++
4 files changed, 41 insertions(+)
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 6a7ba416cf8a..07fb9855cd20 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -2528,6 +2528,16 @@ duplicate_decls (tree newdecl, tree olddecl, bool
hiding, bool was_hidden)
}
}
+ /* Propagate purviewness and importingness as with
+ set_instantiating_module. */
+ if (modules_p ())
+ {
+ if (DECL_MODULE_PURVIEW_P (new_result))
+ DECL_MODULE_PURVIEW_P (old_result) = true;
+ if (!DECL_MODULE_IMPORT_P (new_result))
+ DECL_MODULE_IMPORT_P (old_result) = false;
+ }
+
/* If the new declaration is a definition, update the file and
line information on the declaration, and also make
the old declaration the same definition. */
diff --git a/gcc/testsuite/g++.dg/modules/merge-18_a.H
b/gcc/testsuite/g++.dg/modules/merge-18_a.H
new file mode 100644
index 000000000000..8d86ad980ba5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/merge-18_a.H
@@ -0,0 +1,8 @@
+// PR c++/116803
+// { dg-additional-options "-fmodule-header" }
+// { dg-module-cmi {} }
+
+namespace ns {
+ template <typename T> void foo();
+ template <typename T> extern const int bar;
+}
diff --git a/gcc/testsuite/g++.dg/modules/merge-18_b.H
b/gcc/testsuite/g++.dg/modules/merge-18_b.H
new file mode 100644
index 000000000000..2a762e2ac498
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/merge-18_b.H
@@ -0,0 +1,13 @@
+// PR c++/116803
+// { dg-additional-options "-fmodule-header -fdump-lang-module" }
+// { dg-module-cmi {} }
+
+import "merge-18_a.H";
+
+namespace ns {
+ template <typename T> void foo() {}
+ template <typename T> const int bar = 123;
+}
+
+// { dg-final { scan-lang-dump {Writing definition '::ns::template foo'}
module } }
+// { dg-final { scan-lang-dump {Writing definition '::ns::template bar'}
module } }
diff --git a/gcc/testsuite/g++.dg/modules/merge-18_c.C
b/gcc/testsuite/g++.dg/modules/merge-18_c.C
new file mode 100644
index 000000000000..b90d85f75024
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/merge-18_c.C
@@ -0,0 +1,10 @@
+// PR c++/116803
+// { dg-module-do link }
+// { dg-additional-options "-fmodules-ts" }
+
+import "merge-18_b.H";
+
+int main() {
+ ns::foo<int>();
+ static_assert(ns::bar<int> == 123);
+}
