c++ modules: static var in inline function [PR104433]

The below testcase fails to link with the error

  undefined reference to `f()::y'

ultimately because during stream out for the static VAR_DECL y we
override DECL_EXTERNAL to true, which later during IPA confuses
symbol_table::remove_unreachable_nodes into thinking it's safe
to not emit the symbol.

The streaming code here already avoids overriding DECL_EXTERNAL for
inline vars and functions, so it seems natural to extend this to
static vars from an inline function.

	PR c++/104433

gcc/cp/ChangeLog:

	* module.cc (trees_out::core_bools): Don't override
	DECL_EXTERNAL to true for static variables from an inline
	function.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/static-2_a.H: New test.
	* g++.dg/modules/static-2_b.C: New test.

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index c5eff2199095f265fdccfb541ef45d7e4cfc4b4f..cb1929bc5d55ebbf3af20ef57a62ae38a5361482 100644 (file)
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -5411,6 +5411,9 @@ trees_out::core_bools (tree t)
 
            case VAR_DECL:
              if (TREE_PUBLIC (t)
+                 && !(TREE_STATIC (t)
+                      && DECL_FUNCTION_SCOPE_P (t)
+                      && DECL_DECLARED_INLINE_P (DECL_CONTEXT (t)))
                  && !DECL_VAR_DECLARED_INLINE_P (t))
                is_external = true;
              break;

diff --git a/gcc/testsuite/g++.dg/modules/static-2_a.H b/gcc/testsuite/g++.dg/modules/static-2_a.H
new file mode 100644 (file)
index 0000000..65c7619
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/static-2_a.H
@@ -0,0 +1,8 @@
+// PR c++/104433
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+
+inline int* f() {
+  static int y;
+  return &y;
+}

diff --git a/gcc/testsuite/g++.dg/modules/static-2_b.C b/gcc/testsuite/g++.dg/modules/static-2_b.C
new file mode 100644 (file)
index 0000000..bfd35b0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/static-2_b.C
@@ -0,0 +1,9 @@
+// PR c++/104433
+// { dg-additional-options -fmodules-ts }
+// { dg-do link }
+
+import "static-2_a.H";
+
+int main() {
+  f();
+}