Re: [PATCH] c++: visibility wrt template and ptrmem targs [PR70413]

[Jason Merrill via Gcc-patches]

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.

-- >8 --

When constraining the visibility of an instantiation, we weren't
properly considering the visibility of PTRMEM_CST and TEMPLATE_DECL
template arguments.

        PR c++/70413

gcc/cp/ChangeLog:

        * decl2.cc (min_vis_expr_r): Handle PTRMEM_CST and TEMPLATE_DECL.

gcc/testsuite/ChangeLog:

        * g++.dg/abi/no-linkage-expr2.C: New test.
        * g++.dg/abi/no-linkage-expr3.C: New test.
---
  gcc/cp/decl2.cc                             | 18 ++++++++++++++----
  gcc/testsuite/g++.dg/abi/no-linkage-expr2.C | 15 +++++++++++++++
  gcc/testsuite/g++.dg/abi/no-linkage-expr3.C | 17 +++++++++++++++++
  3 files changed, 46 insertions(+), 4 deletions(-)
  create mode 100644 gcc/testsuite/g++.dg/abi/no-linkage-expr2.C
  create mode 100644 gcc/testsuite/g++.dg/abi/no-linkage-expr3.C

diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index b402befba6d..5006372a646 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -2582,7 +2582,10 @@ 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:
@@ -2593,15 +2596,22 @@ 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:

+      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/abi/no-linkage-expr2.C 
b/gcc/testsuite/g++.dg/abi/no-linkage-expr2.C
new file mode 100644
index 00000000000..db23570bb08
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/no-linkage-expr2.C
@@ -0,0 +1,15 @@
+// PR c++/70413
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler-not "weak.*_Z" } }
+
+namespace {
+  template<class> struct A;
+  template<class> using B = int;
+}
+
+template<template<class> class Q> void f() { }
+
+int main() {
+  f<A>();
+  f<B>();
+}
diff --git a/gcc/testsuite/g++.dg/abi/no-linkage-expr3.C 
b/gcc/testsuite/g++.dg/abi/no-linkage-expr3.C
new file mode 100644
index 00000000000..a2db1a45c74
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/no-linkage-expr3.C
@@ -0,0 +1,17 @@
+// PR c++/70413
+// { dg-final { scan-assembler-not "weak.*_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>();
+}