TAO fails to compile using gcc12

[tmayoff]

Version

Master branch (and some of the versions used for OpenDDS)

Host machine and operating system

Fedora 36

Compiler name and version (including patch level)

gcc-12.0.1
clang-14.0.0

The $ACE_ROOT/ace/config.h file

config-linux.h

The $ACE_ROOT/include/makeinclude/platform_macros.GNU file

This was taken from the github workflow

ipv6=1
xerces3=1
ssl=1
INSTALL_PREFIX =/home/tyler/oss/ACE_TAO/installed
CCFLAGS+=-std=c++20
include /home/tyler/oss/ACE_TAO/ACE/include/makeinclude/platform_linux.GNU

AREA/CLASS/EXAMPLE AFFECTED:

Compilation fails here:
../../tao/Any_Insert_Policy_T.h:42:14: error: no viable overloaded '<<='

The problem effects:

Fails to compile

Synopsis

Compilation fails here:
../../tao/Any_Insert_Policy_T.h:42:14: error: no viable overloaded '<<='

Description

There's some more information in this issue on the OpenDDS:
OpenDDS/OpenDDS#3495

Repeat by

Seems to be an issue with gcc12

I'd like to help fix this but I'm not sure how to go about that with this one

[Sascha-Clausen]

To build and use ACE/TAO with GCC 12 you have to add

#define ACE_ANY_OPS_USE_NAMESPACE

to your ACE/config.h

https://www.gnu.org/software/gcc/gcc-12/changes.html
Two-stage name lookup for dependent operator expressions has been corrected (PR51577)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51577
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51577#c23

[jwillemsen]

Please open a pull request to add this to the ACE specific config header file and to add gcc12 to github actions CI

[mitza-oci]

Does anyone have evidence of a build with ACE_ANY_OPS_USE_NAMESPACE working with any currently supported compiler? By working I mean at least compiling all of TAO_ACE.mwc and IDL_Test. Maybe @Sascha-Clausen has some experience with it?

What I'm seeing so far is that there are places in the compiler like be_visitor_array_any_op_ch::visit_array that don't mention ACE_ANY_OPS_USE_NAMESPACE so it seems to be incomplete.

[mitza-oci]

Does anyone have evidence of a build with ACE_ANY_OPS_USE_NAMESPACE working with any currently supported compiler? By working I mean at least compiling all of TAO_ACE.mwc and IDL_Test. Maybe @Sascha-Clausen has some experience with it?

And I forgot to mention... it may make a difference if versioned namespaces are enabled (MPC feature versioned_namespace=1).

[jwillemsen]

Not the combination as far as I know, TAOX11 uses versioned namespaces for the core of TAO but that is a limited set of types used and we don't support Solaris/Embarcadero C++ Builder which seem to require ACE_ANY_OPS_USE_NAMESPACE. This feature was added by HP in the past but they also didn't use versioned namespaces

[mitza-oci]

OK, based on what I learned over the past few days I'm abandoning efforts on ACE_ANY_OPS_USE_NAMESPACE since it was not sufficient to solve the problem and doesn't seem to be necessary either.

Because some overloads of operator<<= are already in ::VERSION_NS::CORBA (or just ::CORBA without the versioned namespace feature) unconditionally (see TAO/tao/AnyTypeCode/SystemExceptionA.h -- not sure if that's a bug or a feature), I'm going to try moving the rest into the same namespace.

When Any_Insert_Policy_Stream<S>::any_insert gets instantiated, the overload resolution for operator<<= should always consider the CORBA namespace since the left-hand-side arg comes from there.