On 12/21/23 14:12, Patrick Palka wrote:
On Sat, 16 Sep 2023, Jason Merrill wrote:
On 9/15/23 12:03, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?
OK.
Thanks a lot. Testing on cmcstl2 revealed that we don't maintain
visibility flags on alias templates properly, and so we can't trust
them when constraining visibilitiy. So I went ahead and pushed the
following restricted version of the patch which excludes alias templates
(and adds a couple of alias template targ linkage tests):
OK.
-- >8 --
Subject: [PATCH] c++: visibility wrt template and ptrmem targs [PR70413]
When constraining the visibility of an instantiation, we weren't
properly considering the visibility of PTRMEM_CST and TEMPLATE_DECL
template arguments.
This patch fixes this. It turns out we don't maintain the relevant
visibility flags for alias templates (e.g. TREE_PUBLIC is never set),
so continue to ignore alias template template arguments for now.
PR c++/70413
PR c++/107906
gcc/cp/ChangeLog:
* decl2.cc (min_vis_expr_r): Handle PTRMEM_CST and TEMPLATE_DECL
other than those for alias templates.
gcc/testsuite/ChangeLog:
* g++.dg/template/linkage2.C: New test.
* g++.dg/template/linkage3.C: New test.
* g++.dg/template/linkage4.C: New test.
* g++.dg/template/linkage4a.C: New test.
---
gcc/cp/decl2.cc | 22 ++++++++++++++++++----
gcc/testsuite/g++.dg/template/linkage2.C | 13 +++++++++++++
gcc/testsuite/g++.dg/template/linkage3.C | 17 +++++++++++++++++
gcc/testsuite/g++.dg/template/linkage4.C | 16 ++++++++++++++++
gcc/testsuite/g++.dg/template/linkage4a.C | 14 ++++++++++++++
5 files changed, 78 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/template/linkage2.C
create mode 100644 gcc/testsuite/g++.dg/template/linkage3.C
create mode 100644 gcc/testsuite/g++.dg/template/linkage4.C
create mode 100644 gcc/testsuite/g++.dg/template/linkage4a.C
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 0850d3f5bce..4777ceb8af7 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -2655,7 +2655,10 @@ min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void
*data)
int *vis_p = (int *)data;
int tpvis = VISIBILITY_DEFAULT;
- switch (TREE_CODE (*tp))
+ tree t = *tp;
+ if (TREE_CODE (t) == PTRMEM_CST)
+ t = PTRMEM_CST_MEMBER (t);
+ switch (TREE_CODE (t))
{
case CAST_EXPR:
case IMPLICIT_CONV_EXPR:
@@ -2666,15 +2669,26 @@ min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void
*data)
case NEW_EXPR:
case CONSTRUCTOR:
case LAMBDA_EXPR:
- tpvis = type_visibility (TREE_TYPE (*tp));
+ tpvis = type_visibility (TREE_TYPE (t));
break;
+ case TEMPLATE_DECL:
+ if (DECL_ALIAS_TEMPLATE_P (t))
+ /* FIXME: We don't maintain TREE_PUBLIC / DECL_VISIBILITY for
+ alias templates so we can't trust it here (PR107906). */
+ break;
+ t = DECL_TEMPLATE_RESULT (t);
+ /* Fall through. */
case VAR_DECL:
case FUNCTION_DECL:
- if (! TREE_PUBLIC (*tp))
+ if (! TREE_PUBLIC (t))
tpvis = VISIBILITY_ANON;
else
- tpvis = DECL_VISIBILITY (*tp);
+ tpvis = DECL_VISIBILITY (t);
+ break;
+
+ case FIELD_DECL:
+ tpvis = type_visibility (DECL_CONTEXT (t));
break;
default:
diff --git a/gcc/testsuite/g++.dg/template/linkage2.C
b/gcc/testsuite/g++.dg/template/linkage2.C
new file mode 100644
index 00000000000..08fb6930262
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/linkage2.C
@@ -0,0 +1,13 @@
+// PR c++/70413
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler-not "(weak|glob)\[^\n\]*_Z" } }
+
+namespace {
+ template<class> struct A;
+}
+
+template<template<class> class Q> void f() { }
+
+int main() {
+ f<A>();
+}
diff --git a/gcc/testsuite/g++.dg/template/linkage3.C
b/gcc/testsuite/g++.dg/template/linkage3.C
new file mode 100644
index 00000000000..257aab33b38
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/linkage3.C
@@ -0,0 +1,17 @@
+// PR c++/70413
+// { dg-final { scan-assembler-not "(weak|glob)\[^\n\]*_Z" } }
+
+namespace {
+ struct A {
+ void f();
+ int m;
+ };
+}
+
+template<void(A::*)()> void g() { }
+template<int A::*> void h() { }
+
+int main() {
+ g<&A::f>();
+ h<&A::m>();
+}
diff --git a/gcc/testsuite/g++.dg/template/linkage4.C
b/gcc/testsuite/g++.dg/template/linkage4.C
new file mode 100644
index 00000000000..03630eebd3d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/linkage4.C
@@ -0,0 +1,16 @@
+// PR c++/107906
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler-not "(weak|glob)\[^\n\]*_Z" { xfail *-*-* } } }
+
+namespace {
+ template<class> using X = int;
+ struct A {
+ template<class> using X = int;
+ };
+}
+template<template<class> class Q> void f() { }
+
+int main() {
+ f<X>();
+ f<A::X>();
+}
diff --git a/gcc/testsuite/g++.dg/template/linkage4a.C
b/gcc/testsuite/g++.dg/template/linkage4a.C
new file mode 100644
index 00000000000..f1934fd6557
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/linkage4a.C
@@ -0,0 +1,14 @@
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler "(weak|glob)\[^\n\]*_Z1fI1XEvv" } }
+// { dg-final { scan-assembler "(weak|glob)\[^\n\]*_Z1fIN1A1XEEvv" } }
+
+template<class> using X = int;
+struct A {
+ template<class> using X = int;
+};
+template<template<class> class Q> void f() { }
+
+int main() {
+ f<X>();
+ f<A::X>();
+}
