c++: Non-inline temploid friends should still be COMDAT [PR122819]

Modules allow temploid friends to no longer be implicitly inline, as
functions defined in a class body will not be implicitly inline if
attached to a named module.

This requires us to clean up linkage handling a little bit, mostly by
replacing usages of 'DECL_TEMPLATE_INSTANTIATION' with
'DECL_TEMPLOID_INSTANTIATION' when determining if an entity has vague
linkage.

	PR c++/122819

gcc/cp/ChangeLog:

	* decl.cc (start_preparsed_function): Use
	DECL_TEMPLOID_INSTANTIATION instead of
	DECL_TEMPLATE_INSTANTIATION to check vague linkage.
	* decl2.cc (vague_linkage_p): Likewise.
	(c_parse_final_cleanups): Simplify condition.
	* semantics.cc (expand_or_defer_fn_1): Also check for temploid
	friend functions.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/tpl-friend-22.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
Reviewed-by: Jason Merrill <jason@redhat.com>

4 files changed, 32 insertions, 7 deletions

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 74c862e..31081b3 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -19750,7 +19750,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
 	}
     }
 
-  bool honor_interface = (!DECL_TEMPLATE_INSTANTIATION (decl1)
+  bool honor_interface = (!DECL_TEMPLOID_INSTANTIATION (decl1)
 			  /* Implicitly-defined methods (like the
 			     destructor for a class in which no destructor
 			     is explicitly declared) must not be defined
@@ -19781,7 +19781,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
   else if (!finfo->interface_unknown && honor_interface)
     {
       if (DECL_DECLARED_INLINE_P (decl1)
-	  || DECL_TEMPLATE_INSTANTIATION (decl1))
+	  || DECL_TEMPLOID_INSTANTIATION (decl1))
 	{
 	  DECL_EXTERNAL (decl1)
 	    = (finfo->interface_only
@@ -19823,7 +19823,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
 	DECL_EXTERNAL (decl1) = 0;
 
       if ((DECL_DECLARED_INLINE_P (decl1)
-	   || DECL_TEMPLATE_INSTANTIATION (decl1))
+	   || DECL_TEMPLOID_INSTANTIATION (decl1))
 	  && ! DECL_INTERFACE_KNOWN (decl1))
 	DECL_DEFER_OUTPUT (decl1) = 1;
       else
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 8ec9740..01bf26b 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -2510,7 +2510,7 @@ vague_linkage_p (tree decl)
       || (TREE_CODE (decl) == FUNCTION_DECL
 	  && DECL_DECLARED_INLINE_P (decl))
       || (DECL_LANG_SPECIFIC (decl)
-	  && DECL_TEMPLATE_INSTANTIATION (decl))
+	  && DECL_TEMPLOID_INSTANTIATION (decl))
       || (VAR_P (decl) && DECL_INLINE_VAR_P (decl)))
     return true;
   else if (DECL_FUNCTION_SCOPE_P (decl))
@@ -5850,8 +5850,7 @@ c_parse_final_cleanups (void)
 	  && !(header_module_p ()
 	       && (DECL_DEFAULTED_FN (decl) || decl_tls_wrapper_p (decl)))
 	  /* Don't complain if the template was defined.  */
-	  && !((DECL_TEMPLATE_INSTANTIATION (decl)
-		|| DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl))
+	  && !(DECL_TEMPLOID_INSTANTIATION (decl)
 	       && DECL_INITIAL (DECL_TEMPLATE_RESULT
 				(template_for_substitution (decl))))
 	  && warning_at (DECL_SOURCE_LOCATION (decl), 0,
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 331db16..b32ab2f 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -5537,7 +5537,9 @@ expand_or_defer_fn_1 (tree fn)
      of the compilation.  Until that point, we do not want the back
      end to output them -- but we do want it to see the bodies of
      these functions so that it can inline them as appropriate.  */
-  if (DECL_DECLARED_INLINE_P (fn) || DECL_IMPLICIT_INSTANTIATION (fn))
+  if (DECL_DECLARED_INLINE_P (fn)
+      || DECL_IMPLICIT_INSTANTIATION (fn)
+      || DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (fn))
     {
       if (DECL_INTERFACE_KNOWN (fn))
 	/* We've already made a decision as to how this function will
diff --git a/gcc/testsuite/g++.dg/modules/tpl-friend-22.C b/gcc/testsuite/g++.dg/modules/tpl-friend-22.C
new file mode 100644
index 0000000..a77d1cb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/tpl-friend-22.C
@@ -0,0 +1,24 @@
+// PR c++/122819
+// { dg-do compile { target *-*-*gnu* } }
+// { dg-additional-options "-fmodules" }
+
+export module M;
+
+template <typename T> struct S;
+void foo(S<float>);
+
+template <typename T> struct S {
+  friend void foo(S) {}
+};
+
+void foo(S<double>);
+
+void use() {
+  foo(S<int>{});
+  foo(S<float>{});
+  foo(S<double>{});
+}
+
+// { dg-final { scan-assembler "_ZW1M3fooS_1SIiE,comdat" } }
+// { dg-final { scan-assembler "_ZW1M3fooS_1SIfE,comdat" } }
+// { dg-final { scan-assembler "_ZW1M3fooS_1SIdE,comdat" } }