From 726723c476800285cfbdfce612cedde4a9a7ad58 Mon Sep 17 00:00:00 2001
From: Nathaniel Shead <nathanieloshead@gmail.com>
Date: Wed, 15 Nov 2023 20:50:53 +1100
Subject: [PATCH] c++: Allow exporting const-qualified namespace-scope
 variables [PR99232]

By [basic.link] p3.2.1, a non-template non-volatile const-qualified
variable is not necessarily internal linkage in a module declaration,
and rather may have module linkage (or external linkage if it is
exported, see p4.8).

	PR c++/99232

gcc/cp/ChangeLog:

	* decl.cc (grokvardecl): Don't mark variables attached to
	modules as internal.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/pr99232_a.C: New test.
	* g++.dg/modules/pr99232_b.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
 gcc/cp/decl.cc                           |  3 ++-
 gcc/testsuite/g++.dg/modules/pr99232_a.C | 12 ++++++++++++
 gcc/testsuite/g++.dg/modules/pr99232_b.C | 13 +++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/modules/pr99232_a.C
 create mode 100644 gcc/testsuite/g++.dg/modules/pr99232_b.C

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 16b04ebe0f8..ed1401591fa 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -11006,7 +11006,8 @@ grokvardecl (tree type,
 			    && (DECL_THIS_EXTERN (decl)
 				|| ! constp
 				|| volatilep
-				|| inlinep));
+				|| inlinep
+				|| module_attach_p ()));
       TREE_STATIC (decl) = ! DECL_EXTERNAL (decl);
     }
   /* Not at top level, only `static' makes a static definition.  */
diff --git a/gcc/testsuite/g++.dg/modules/pr99232_a.C b/gcc/testsuite/g++.dg/modules/pr99232_a.C
new file mode 100644
index 00000000000..097fb5e4403
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99232_a.C
@@ -0,0 +1,12 @@
+// PR c++/99232
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi pr99232 }
+
+export module pr99232;
+
+export const double lambda{ 1.3 };
+export constexpr int a = 42;
+
+export const double* get_lambda_addr() {
+  return &lambda;
+}
diff --git a/gcc/testsuite/g++.dg/modules/pr99232_b.C b/gcc/testsuite/g++.dg/modules/pr99232_b.C
new file mode 100644
index 00000000000..a36a76fa5b7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99232_b.C
@@ -0,0 +1,13 @@
+// PR c++/99232
+// { dg-module-do run }
+// { dg-additional-options "-fmodules-ts" }
+
+import pr99232;
+
+double foo() { return lambda * 2.0; }
+static_assert(a == 42);
+
+int main() {
+  if (&lambda != get_lambda_addr())
+    __builtin_abort();
+}