Optimization bug in C++

["Knut-Håvard Aksnes" <knut at orion dot no>]

A rewrite of the bug report previously posted as "serious brain damage
in C++ compiler"

The C++ compiler does some very dangerous and optimizations. This
breaks code conformant to the standard CORBA C++ bindings. 

The problem is the choice of cast operators, exemplified by these messages: 

SerialServant.cpp:19: warning: choosing `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *&()' over `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *const &() const'
SerialServant.cpp:19: warning:   for conversion from `NO::orion::markfeed::Feed_var' to `CORBA_Object *'
SerialServant.cpp:19: warning:   because conversion sequence for the argument is better

Explicit casts are used in the code to ensure usage of the right
conversion. The compiler seems to override these casts, this leads to
serious memory leaks in corba code.

Semantics of conversion operators in corba: 

X_var cast to  X *	 The returned object is owned by the caller.
X_var cast to const X *	 The returned object is owned by the X_var object.

Using cast to pointer where cast to pointer to const is intended
creates memory leaks,

The SerialServant.ii.bz2 file can be found at:
http://www.orion.no/SerialServant.ii.bz2

Output from compilation follows:

cd /home/knut/devroot/src/NordPool/Markfeed/
c++ -v --save-temps -DPACKAGE=\"markfeed\" -DVERSION=\"2.91\" -DHAVE_LIBRT=1 -DHAVE_LIBRESOLV=1 -DHAVE_STRSTREAM=1  -I. -I.    -DWITHOUT_NANA  -D_GNU_SOURCE -DACE_HAS_GNU_REPO -DACE_LACKS_PRAGMA_ONCE -D_POSIX_THREADS -D_POSIX_THREAD_SAFE_FUNCTIONS -D_REENTRANT -I/usr/local/ACE_wrappers/TAO/orbsvcs/orbsvcs -I/usr/local/ACE_wrappers/TAO -I/usr/local/ACE_wrappers   -frepo -pipe -g -O2 -c SerialServant.cpp

c++: Warning: -pipe ignored since -save-temps specified
Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.1/specs
gcc version 2.95.1 19990816 (release)
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.1/cpp -lang-c++ -v -I. -I. -I/usr/local/ACE_wrappers/TAO/orbsvcs/orbsvcs -I/usr/local/ACE_wrappers/TAO -I/usr/local/ACE_wrappers -D__GNUC__=2 -D__GNUG__=2 -D__GNUC_MINOR__=95 -D__cplusplus -D__ELF__ -Dunix -D__i386__ -Dlinux -D__ELF__ -D__unix__ -D__i386__ -D__linux__ -D__unix -D__linux -Asystem(posix) -D__EXCEPTIONS -D__OPTIMIZE__ -g -Acpu(i386) -Amachine(i386) -Di386 -D__i386 -D__i386__ -Di686 -Dpentiumpro -D__i686 -D__i686__ -D__pentiumpro -D__pentiumpro__ -DPACKAGE="markfeed" -DVERSION="2.91" -DHAVE_LIBRT=1 -DHAVE_LIBRESOLV=1 -DHAVE_STRSTREAM=1 -DWITHOUT_NANA -D_GNU_SOURCE -DACE_HAS_GNU_REPO -DACE_LACKS_PRAGMA_ONCE -D_POSIX_THREADS -D_POSIX_THREAD_SAFE_FUNCTIONS -D_REENTRANT SerialServant.cpp SerialServant.ii
GNU CPP version 2.95.1 19990816 (release) (i386 Linux/ELF)
#include "..." search starts here:
#include <...> search starts here:
 .
 /usr/local/ACE_wrappers/TAO/orbsvcs/orbsvcs
 /usr/local/ACE_wrappers/TAO
 /usr/local/ACE_wrappers
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.1/../../../../include/g++-3
 /usr/local/include
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.1/../../../../i686-pc-linux-gnu/include
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.1/include
 /usr/include
End of search list.
The following default directories have been omitted from the search path:
End of omitted list.
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.1/cc1plus SerialServant.ii -quiet -dumpbase SerialServant.cc -g -O2 -version -frepo -o SerialServant.s
GNU C++ version 2.95.1 19990816 (release) (i686-pc-linux-gnu) compiled by GNU C version 2.95.1 19990816 (release).
SerialServant.cpp: In method `void NO::orion::markfeed::SerialServant::remove()':
SerialServant.cpp:19: warning: choosing `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *&()' over `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *const &() const'
SerialServant.cpp:19: warning:   for conversion from `NO::orion::markfeed::Feed_var' to `CORBA_Object *'
SerialServant.cpp:19: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `void NO::orion::markfeed::SerialServant::disconnect_push_supplier()':
SerialServant.cpp:36: warning: choosing `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *&()' over `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *const &() const'
SerialServant.cpp:36: warning:   for conversion from `NO::orion::markfeed::PushConsumer_var' to `CORBA_Object *'
SerialServant.cpp:36: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `class NO::orion::markfeed::PushConsumer * NO::orion::markfeed::SerialServant::admin_interface()':
SerialServant.cpp:41: warning: choosing `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *&()' over `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *const &() const'
SerialServant.cpp:41: warning:   for conversion from `NO::orion::markfeed::PushConsumer_var' to `NO::orion::markfeed::PushConsumer *'
SerialServant.cpp:41: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `class NO::orion::markfeed::Feed * NO::orion::markfeed::SerialServant::peer()':
SerialServant.cpp:90: warning: choosing `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *&()' over `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *const &() const'
SerialServant.cpp:90: warning:   for conversion from `NO::orion::markfeed::Feed_var' to `NO::orion::markfeed::Feed *'
SerialServant.cpp:90: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `void NO::orion::markfeed::SerialServant::dump_config()':
SerialServant.cpp:186: warning: choosing `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *&()' over `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *const &() const'
SerialServant.cpp:186: warning:   for conversion from `NO::orion::markfeed::Feed_var' to `CORBA_Object *'
SerialServant.cpp:186: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `void NO::orion::markfeed::SerialServant::notify(const char *)':
SerialServant.cpp:193: warning: choosing `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *&()' over `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *const &() const'
SerialServant.cpp:193: warning:   for conversion from `NO::orion::markfeed::PushConsumer_var' to `CORBA_Object *'
SerialServant.cpp:193: warning:   because conversion sequence for the argument is better
SerialServant.cpp:194: warning: choosing `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *&()' over `NO::orion::markfeed::PushConsumer_var::operator NO::orion::markfeed::PushConsumer *const &() const'
SerialServant.cpp:194: warning:   for conversion from `NO::orion::markfeed::PushConsumer_var' to `CORBA_Object *'
SerialServant.cpp:194: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `void NO::orion::markfeed::SerialServant::stop()':
SerialServant.cpp:204: warning: choosing `PortableServer::_tao_seq_Octet_var::operator PortableServer::_tao_seq_Octet &()' over `PortableServer::_tao_seq_Octet_var::operator const PortableServer::_tao_seq_Octet &() const'
SerialServant.cpp:204: warning:   for conversion from `PortableServer::ObjectId_var' to `const PortableServer::ObjectId &'
SerialServant.cpp:204: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `NO::orion::markfeed::SerialServant::SerialServant(const string &, const string &, unsigned int, NO::orion::markfeed::Feed *, bool, NO::orion::markfeed::RunState)':
SerialServant.cpp:297: warning: choosing `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *&()' over `NO::orion::markfeed::Feed_var::operator NO::orion::markfeed::Feed *const &() const'
SerialServant.cpp:297: warning:   for conversion from `NO::orion::markfeed::Feed_var' to `CORBA_Object *'
SerialServant.cpp:297: warning:   because conversion sequence for the argument is better
SerialServant.cpp:301: warning: choosing `PortableServer::_tao_seq_Octet_var::operator PortableServer::_tao_seq_Octet &()' over `PortableServer::_tao_seq_Octet_var::operator const PortableServer::_tao_seq_Octet &() const'
SerialServant.cpp:301: warning:   for conversion from `PortableServer::ObjectId_var' to `const PortableServer::ObjectId &'
SerialServant.cpp:301: warning:   because conversion sequence for the argument is better
SerialServant.cpp:324: warning: choosing `CORBA_String_var::operator char *()' over `CORBA_String_var::operator const char *() const'
SerialServant.cpp:324: warning:   for conversion from `CORBA::String_var' to `const char *'
SerialServant.cpp:324: warning:   because conversion sequence for the argument is better
SerialServant.cpp: In method `bool NO::orion::markfeed::SerialServant::Connected::process_line(const string &)':
SerialServant.cpp:977: warning: choosing `CORBA_String_var::operator char *()' over `CORBA_String_var::operator const char *() const'
SerialServant.cpp:977: warning:   for conversion from `CORBA::String_var' to `const char *'
SerialServant.cpp:977: warning:   because conversion sequence for the argument is better
 /usr/local/i686-pc-linux-gnu/bin/as -V -Qy -o SerialServant.o SerialServant.s
GNU assembler version 2.9.1 (i686-pc-linux-gnu), using BFD version 2.9.1.0.19

Compilation finished at Thu Aug 26 12:29:54