Re: [PATCH] c++: abi_tag attribute on templates [PR109715]

[Patrick Palka <ppalka@redhat.com>]

On Thu, 14 Dec 2023, Jason Merrill wrote:

> On 12/14/23 14:17, Patrick Palka wrote:
> > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> > trunk?  Do we want to condition this on abi_check (19)?
> 
> I think we do, sadly.

Sounds good, like so?  Bootstrap and regtest in progress.

-- >8 --

Subject: [PATCH] c++: abi_tag attribute on templates [PR109715]

As with other declaration attributes, we need to look through
TEMPLATE_DECL when looking up the abi_tag attribute.

	PR c++/109715

gcc/cp/ChangeLog:

	* mangle.cc (get_abi_tags): Look through TEMPLATE_DECL.

gcc/testsuite/ChangeLog:

	* g++.dg/abi/abi-tag25.C: New test.
	* g++.dg/abi/abi-tag25a.C: New test.
---
 gcc/cp/mangle.cc                      |  6 ++++++
 gcc/testsuite/g++.dg/abi/abi-tag25.C  | 17 +++++++++++++++++
 gcc/testsuite/g++.dg/abi/abi-tag25a.C | 11 +++++++++++
 3 files changed, 34 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/abi/abi-tag25.C
 create mode 100644 gcc/testsuite/g++.dg/abi/abi-tag25a.C

diff --git a/gcc/cp/mangle.cc b/gcc/cp/mangle.cc
index 0684f0e6038..e3383df1836 100644
--- a/gcc/cp/mangle.cc
+++ b/gcc/cp/mangle.cc
@@ -530,6 +530,12 @@ get_abi_tags (tree t)
   if (DECL_P (t) && DECL_DECLARES_TYPE_P (t))
     t = TREE_TYPE (t);
 
+  if (TREE_CODE (t) == TEMPLATE_DECL
+      && DECL_TEMPLATE_RESULT (t)
+      /* We used to ignore abi_tag on function and variable templates.  */
+      && abi_check (19))
+    t = DECL_TEMPLATE_RESULT (t);
+
   tree attrs;
   if (TYPE_P (t))
     attrs = TYPE_ATTRIBUTES (t);
diff --git a/gcc/testsuite/g++.dg/abi/abi-tag25.C b/gcc/testsuite/g++.dg/abi/abi-tag25.C
new file mode 100644
index 00000000000..9847f0dccc8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/abi-tag25.C
@@ -0,0 +1,17 @@
+// PR c++/109715
+// { dg-do compile { target c++11 } }
+
+template<class T>
+[[gnu::abi_tag("foo")]] void fun() { }
+
+template void fun<int>();
+
+#if __cpp_variable_templates
+template<class T>
+[[gnu::abi_tag("foo")]] int var = 0;
+
+template int var<int>;
+#endif
+
+// { dg-final { scan-assembler "_Z3funB3fooIiEvv" } }
+// { dg-final { scan-assembler "_Z3varB3fooIiE" { target c++14 } } }
diff --git a/gcc/testsuite/g++.dg/abi/abi-tag25a.C b/gcc/testsuite/g++.dg/abi/abi-tag25a.C
new file mode 100644
index 00000000000..9499b5614cd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/abi-tag25a.C
@@ -0,0 +1,11 @@
+// PR c++/109715
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-fabi-version=18 -fabi-compat-version=18 -Wabi=0" }
+
+#include "abi-tag25.C"
+
+// { dg-warning "mangled name" "" { target *-*-* } 5 }
+// { dg-warning "mangled name" "" { target *-*-* } 11 }
+
+// { dg-final { scan-assembler "_Z3funIiEvv" } }
+// { dg-final { scan-assembler "_Z3varIiE" { target c++14 } } }
-- 
2.43.0.76.g1a87c842ec