From 247643c7e21b087e6c93b8b8d49b4268bf84b03b Mon Sep 17 00:00:00 2001
From: Nathaniel Shead <nathanieloshead@gmail.com>
Date: Fri, 4 Oct 2024 12:01:38 +1000
Subject: [PATCH] c++: Allow references to internal-linkage vars in C++11
[PR113266]
[temp.arg.nontype] changed in C++11 to allow naming internal-linkage
variables and functions. We currently already handle internal-linkage
functions, but variables were missed; this patch updates this.
PR c++/113266
PR c++/116911
gcc/cp/ChangeLog:
* parser.cc (cp_parser_template_argument): Allow
internal-linkage variables since C++11.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/nontype6.C: New test.
Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
gcc/cp/parser.cc | 17 ++++++++++++-----
gcc/testsuite/g++.dg/cpp0x/nontype6.C | 19 +++++++++++++++++++
2 files changed, 31 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/nontype6.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 08f9c89f1f04..9d31a975dcf9 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -19864,9 +19864,11 @@ cp_parser_template_argument (cp_parser* parser)
-- the name of a non-type template-parameter; or
- -- the name of an object or function with external linkage...
+ -- the name of an object or function with external (or internal,
+ since C++11) linkage...
- -- the address of an object or function with external linkage...
+ -- the address of an object or function with external (or internal,
+ since C++11) linkage...
-- a pointer to member... */
/* Look for a non-type template parameter. */
@@ -19929,11 +19931,16 @@ cp_parser_template_argument (cp_parser* parser)
probe = TREE_OPERAND (probe, 1);
if (VAR_P (probe))
{
- /* A variable without external linkage might still be a
+ /* A variable without valid linkage might still be a
valid constant-expression, so no error is issued here
if the external-linkage check fails. */
- if (!address_p && !DECL_EXTERNAL_LINKAGE_P (probe))
- cp_parser_simulate_error (parser);
+ if (!address_p)
+ {
+ linkage_kind linkage = decl_linkage (probe);
+ if (linkage != lk_external
+ && (cxx_dialect < cxx11 || linkage != lk_internal))
+ cp_parser_simulate_error (parser);
+ }
}
else if (is_overloaded_fn (argument))
/* All overloaded functions are allowed; if the external
diff --git a/gcc/testsuite/g++.dg/cpp0x/nontype6.C b/gcc/testsuite/g++.dg/cpp0x/nontype6.C
new file mode 100644
index 000000000000..5543d1e8b6d2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nontype6.C
@@ -0,0 +1,19 @@
+// PR c++/113266, PR c++/116911
+// { dg-do compile }
+
+template <int &> struct a {};
+static int guard1;
+a<guard1> b; // { dg-error "constant-expression|invalid" "" { target c++98_only } }
+
+namespace {
+ int guard2;
+}
+a<guard2> c; // OK in C++98 because guard2 has external linkage
+ // OK since C++11 because we can refer to an internal linkage decl
+
+void nolinkage() {
+ static int guard3;
+ a<guard3> d; // { dg-error "constant-expression|invalid" "" { target c++98_only } }
+ // { dg-error "constant expression|no linkage" "" { target { c++11 && c++14_down } } .-1 }
+ // OK since C++17 since we can now refer to no-linkage decls
+}
--
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