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.
62 строки
1.7 KiB
C++
62 строки
1.7 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 Op {
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public:
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// construction
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Op();
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Op(MPI_Op i);
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Op(const Op& op);
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#if 0 /* OMPI_ENABLE_MPI_PROFILING */
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Op(const PMPI::Op& op) : pmpi_op(op) { }
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#endif
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// destruction
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virtual ~Op();
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// assignment
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Op& operator=(const Op& op);
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Op& operator= (const MPI_Op &i);
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// comparison
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inline bool operator== (const Op &a);
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inline bool operator!= (const Op &a);
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// conversion functions for inter-language operability
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inline operator MPI_Op () const;
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// inline operator MPI_Op* (); //JGS const
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#if 0 /* OMPI_ENABLE_MPI_PROFILING */
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inline operator const PMPI::Op&() const { return pmpi_op; }
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#endif
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// Collective Communication
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//JGS took const out
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virtual void Init(User_function *func, bool commute);
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virtual void Free();
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#if ! 0 /* OMPI_ENABLE_MPI_PROFILING */
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protected:
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MPI_Op mpi_op;
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#endif
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#if 0 /* OMPI_ENABLE_MPI_PROFILING */
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private:
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PMPI::Op pmpi_op;
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#endif
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};
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