0a28212392
(all versions up to and including 20060925). The issue has been
reported to Intel, along with a small [non-MPI] test program that
reproduces the problem (the test program and the OMPI C++ bindings
work fine with Intel C++ 9.0 and many other C++ compilers).
In short, a static initializer for a global variable (i.e., its
constructor is fired before main()) that takes as an argument a
reference to a typedef'd type will simply get the wrong value in the
argument. Specifically:
{{{
namespace MPI {
Intracomm COMM_WORLD(MPI_COMM_WORLD);
}
}}}
The constructor for MPI::Intracomm should get the value of
&ompi_mpi_comm_world. It does not; it seems to get a random value.
As mandated by MPI-2, annex B.13.4, for C/C++ interoperability, the
prototype for this constructor is:
{{{
class Intracomm {
public:
Intracomm(const MPI_Comm& data);
};
}}}
Experiments with icpc 9.1/20060925 have shown that removing the
reference from the prototype makes it work (!). After lots of
discussions about this issue with a C++ expert (Doug Gregor from IU),
we decided the following (cut-n-paste from an e-mail):
-----
> So here's my question: given that OMPI's MPI_<CLASS> types are all
> pointers, is there any legal MPI program that adheres to the above
> bindings that would fail to compile or work properly if we simply
> removed the "&" from the second binding, above?
I don't know of any way that a program could detect this change. FWIW,
the C++ committee has agreed that implementation of the C++ standard
library are allowed to decide arbitrarily between const& and by-value.
If they don't care, MPI users won't care.
When you remove the '&', I suggest also removing the "const". It is
redundant, but can trigger some strange name mangling in Sun's C++
compiler.
-----
So with this change:
* we now work again with the Intel 9.1 compiler
* our C++ bindings do not exactly conform to the MPI-2 spec, but
valid/legal MPI C++ apps cannot tell the difference (i.e., the
functionality is the same)
This commit was SVN r12514.
87 строки
2.5 KiB
C++
87 строки
2.5 KiB
C++
// -*- c++ -*-
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//
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// Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
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// University Research and Technology
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// Corporation. All rights reserved.
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// Copyright (c) 2004-2005 The University of Tennessee and The University
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// of Tennessee Research Foundation. All rights
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// reserved.
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// Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
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// University of Stuttgart. All rights reserved.
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// Copyright (c) 2004-2005 The Regents of the University of California.
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// All rights reserved.
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// Copyright (c) 2006 Cisco Systems, Inc. All rights reserved.
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// $COPYRIGHT$
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//
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// Additional copyrights may follow
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//
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// $HEADER$
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//
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class Intercomm : public Comm {
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#if 0 /* OMPI_ENABLE_MPI_PROFILING */
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// friend class PMPI::Intercomm;
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#endif
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public:
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// construction
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Intercomm() : Comm(MPI_COMM_NULL) { }
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// copy
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Intercomm(const Comm_Null& data) : Comm(data) { }
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// inter-language operability
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Intercomm(MPI_Comm data) : Comm(data) { }
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#if 0 /* OMPI_ENABLE_MPI_PROFILING */
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// copy
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Intercomm(const Intercomm& data) : Comm(data), pmpi_comm(data.pmpi_comm) { }
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Intercomm(const PMPI::Intercomm& d) :
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Comm((const PMPI::Comm&)d), pmpi_comm(d) { }
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// assignment
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Intercomm& operator=(const Intercomm& data) {
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Comm::operator=(data);
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pmpi_comm = data.pmpi_comm; return *this; }
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Intercomm& operator=(const Comm_Null& data) {
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Comm::operator=(data);
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Intercomm& ic = (Intercomm&)data;
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pmpi_comm = ic.pmpi_comm; return *this; }
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// inter-language operability
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Intercomm& operator=(const MPI_Comm& data) {
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Comm::operator=(data);
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pmpi_comm = PMPI::Intercomm(data); return *this; }
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#else
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// copy
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Intercomm(const Intercomm& data) : Comm(data.mpi_comm) { }
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// assignment
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Intercomm& operator=(const Intercomm& data) {
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mpi_comm = data.mpi_comm; return *this; }
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Intercomm& operator=(const Comm_Null& data) {
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mpi_comm = data; return *this; }
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// inter-language operability
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Intercomm& operator=(const MPI_Comm& data) {
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mpi_comm = data; return *this; }
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#endif
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//
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// Groups, Contexts, and Communicators
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//
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Intercomm Dup() const;
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virtual Intercomm& Clone() const;
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virtual int Get_remote_size() const;
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virtual Group Get_remote_group() const;
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virtual Intracomm Merge(bool high);
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virtual Intercomm Create(const Group& group) const;
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virtual Intercomm Split(int color, int key) const;
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};
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