On 11/11/2012 11:58 PM, Jason Merrill wrote:
On 11/11/2012 08:01 AM, Florian Weimer wrote:
I'm not sure if this sufficiently far-reaching. It seems that this
doesn't allow me to implement a virtual function which takes a
std::string parameter in new-ABI-mode when the base class is also used
in old-ABI-mode.
Ah, yes; since virtual functions are called through the vtable the
signatures of virtual functions are also part of the class ABI, so the
base class also needs to be tagged. I guess I should add that to
-Wabi-tag.
Like so:
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 0c1d53def870aef5f785278eb447fceb2974df09
Author: Jason Merrill <ja...@redhat.com>
Date: Tue Nov 13 12:23:52 2012 -0500
* class.c (finish_struct_1): Check virtual functions
for missing ABI tags.
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 0665e90..cdc02ae 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -6275,6 +6275,12 @@ finish_struct_1 (tree t)
/* Here we know enough to change the type of our virtual
function table, but we will wait until later this function. */
build_primary_vtable (CLASSTYPE_PRIMARY_BINFO (t), t);
+
+ /* If we're warning about ABI tags, check the types of the new
+ virtual functions. */
+ if (warn_abi_tag)
+ for (tree v = virtuals; v; v = TREE_CHAIN (v))
+ check_abi_tags (t, TREE_VALUE (v));
}
if (TYPE_CONTAINS_VPTR_P (t))
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 25dd685..43b21c6 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -15622,7 +15622,7 @@ A redeclaration of a function or class must not add new ABI tags,
since doing so would change the mangled name.
The @option{-Wabi-tag} flag enables a warning about a class which does
-not have all the ABI tags used by its subobjects; for users with code
+not have all the ABI tags used by its subobjects and virtual functions; for users with code
that needs to coexist with an earlier ABI, using this option can help
to find all affected types that need to be tagged.
diff --git a/gcc/testsuite/g++.dg/abi/abi-tag4.C b/gcc/testsuite/g++.dg/abi/abi-tag4.C
new file mode 100644
index 0000000..3f8d7bf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/abi-tag4.C
@@ -0,0 +1,8 @@
+// { dg-options "-Wabi-tag" }
+
+struct __attribute ((abi_tag ("X"))) A { };
+
+struct B // { dg-warning "abi tag" }
+{
+ virtual void f(A); // { dg-message "declared here" }
+};
