On 12/16/25 6:34 PM, Nathaniel Shead wrote:
Here's attempt two at this patch, with a testcase for the linker issue
I'd inadvertantly caused with my previous attempt.
Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
-- >8 --
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.
This caused the friend88.C testcase to miscompile however, as 'foo' was
incorrectly having 'DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION' getting
set because it was keeping its tinfo.
This is because 'non_templated_friend_p' was returning 'false', since
the function didn't have a primary template. But that's expected I
think here, so fixed by also returning true for friend declarations
pushed into namespace scope, which still allows dependent nested friends
to be considered templated.
Will that wrongly return true for a friend namespace-scope template?
The test should check that case.
It seems like a bug that TPARMS_PRIMARY_TEMPLATE would ever be null.
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.
* pt.cc (non_templated_friend_p): Namespace-scope friend
function declarations without a primary template are still
non-templated.
* 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.
* g++.dg/template/friend88: New test.
Signed-off-by: Nathaniel Shead <[email protected]>
---
gcc/cp/decl.cc | 6 ++--
gcc/cp/decl2.cc | 5 ++-
gcc/cp/pt.cc | 2 +-
gcc/cp/semantics.cc | 4 ++-
gcc/testsuite/g++.dg/modules/tpl-friend-22.C | 24 +++++++++++++++
gcc/testsuite/g++.dg/template/friend88.C | 32 ++++++++++++++++++++
6 files changed, 65 insertions(+), 8 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/modules/tpl-friend-22.C
create mode 100644 gcc/testsuite/g++.dg/template/friend88.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 74c862ec1c7..31081b390fa 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 8ec9740c8a9..01bf26b1e4f 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/pt.cc b/gcc/cp/pt.cc
index 341e5ab8808..b37de8723ce 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -11652,7 +11652,7 @@ non_templated_friend_p (tree t)
template <class T> friend A<T>::f(); */
tree tmpl = TI_TEMPLATE (ti);
tree primary = DECL_PRIMARY_TEMPLATE (tmpl);
- return (primary && primary != tmpl);
+ return ((primary || DECL_NAMESPACE_SCOPE_P (t)) && primary != tmpl);
}
else
return false;
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index e420fd4ebaf..02a1e6aee0e 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 00000000000..a77d1cbecad
--- /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" } }
diff --git a/gcc/testsuite/g++.dg/template/friend88.C
b/gcc/testsuite/g++.dg/template/friend88.C
new file mode 100644
index 00000000000..73d3d525900
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend88.C
@@ -0,0 +1,32 @@
+// PR c++/122819
+// { dg-do compile { target c++11 } }
+
+template <typename T> struct basic_streambuf;
+using streambuf = basic_streambuf<char>;
+
+struct S {
+ void foo();
+ template <typename T> void bar();
+};
+
+template <typename T> struct X {
+ void foo();
+};
+
+template <typename T> struct basic_streambuf {
+ void qux();
+
+ friend void foo();
+ friend void S::foo();
+ template <typename U> friend void S::bar();
+ template <typename U> friend void X<U>::foo();
+ template <typename U> friend void basic_streambuf<U>::qux();
+};
+extern template struct basic_streambuf<char>;
+
+void foo() {}
+void S::foo() {}
+
+// { dg-final { scan-assembler {_Z3foov:} } }
+// { dg-final { scan-assembler {_ZN1S3fooEv:} } }
+// { dg-final { scan-assembler-not {comdat} } }
