*****************************************************************************

   #####   #####    ####      Formalization of the GPS program logic
  ##       ##  ##  ##         Version 1.7, released 2016-12-20
  ##  ###  #####    ####      
  ##   ##  ##          ##     Copyright (c) Viktor Vafeiadis
   #####   ##       ####      All rights reserved.

*****************************************************************************

**[ CONTENT & INSTALLATION INSTRUCTIONS ]************************************

This directory contains a Coq development for the papers:

* Aaron Turon, Viktor Vafeiadis, and Derek Dreyer.
  GPS: Navigating weak memory with ghosts, protocols, and separation.
  In OOPSLA 2014.
  
* Joseph Tassarotti, Derek Dreyer, and Viktor Vafeiadis.
  Verifying read-copy-update in a logic for weak memory.
  In PLDI 2015.

See:  http://plv.mpi-sws.org/gps/

You will need Coq 8.6 to compile the proofs (http://coq.inria.fr/).
A Makefile is included for convenience: just run "make".

The development consists of the following Coq files: 

* Vbase.v : A collection of useful tactics (a standard library)

* MMergesort.v : A mergesort implementation (a standard library)

* extralib.v : A collection of useful lemmas (a standard library)

* c11.v : Mechanization of the C11 memory model.
  Corresponds to Section A.3 of the GPS paper's appendix

* exps.v : Expressions and operational semantics
  Corresponds to Sections A.1 and A.2 of the GPS paper's appendix

* GpsFraction.v : A simple model of fractional permissions.

* GpsSepAlg.v : Separation algebras.

* GpsModel.v : Our model of protocols, assertions, and local safety
  Corresponds to Sections B.2 and B.3 of the GPS paper's appendix

* GpsModelLemmas.v : Helper lemmas about protocols and assertions

* GpsGlobal.v : Formalization of global safety
  Corresponds to Section B.4 of the GPS paper's appendix

* GpsLogic.v :  Soundness of the logic's proof rules wrt local safety
  Corresponds to Sections B.5 and B.6 of the GPS paper's appendix

* GpsVisible.v : Proofs of the visibility lemmas 
  Corresponds to Section C.3.1 of the GPS paper's appendix

* GpsGlobalHelper.v : Helper lemmas for the adequacy proof

* GpsRely.v : Proof of the rely-step lemma
  Corresponds to Section C.3.2 of the GPS paper's appendix

* GpsGhost.v : Proof of the ghost-step lemmas
  Corresponds to Section C.3.3 of the GPS paper's appendix

* GpsWPE.v  : Proof of the wpe lemma
  Corresponds to Section C.3.4 of the GPS paper's appendix

* GpsGuar.v  : Proof of the guar-step lemma
  Corresponds to Section C.3.5 of the GPS paper's appendix

* GpsPrep.v  : Proof of the prepare lemma
  Corresponds to Section C.3.6 of the GPS paper's appendix

* GpsAdequate.v : Proof of our adequacy theorem
  Corresponds to Section C.3.7 of the GPS paper's appendix

* GpsTokens.v : A simple ghost resource for tokens

* GpsSnapshot.v : The master-snapshot ghost resource
  Contributed by Joseph Tassarotti

* GpsOneShot.v : Verification of a simple message passing program.

**[ LICENSE ]****************************************************************

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
3. Neither the name of the author nor the names of its contributors may be 
   used to endorse or promote products derived from this software without 
   specific prior written permission.

This formalization is provided by the copyright holders and contributors 
"as is" and any express or implied warranties, including, but not limited 
to, the implied warranties of merchantability and fitness for a particular 
purpose are disclaimed.  In no event shall the copyright owner or 
contributors be liable for any direct, indirect, incidental, special, 
exemplary, or consequential damages (including, but not limited to,
procurement of substitute goods or services; loss of use, data, or profits;
or business interruption) however caused and on any theory of liability,
whether in contract, strict liability, or tort (including negligence or
otherwise) arising in any way out of the use of this formalization, even if
advised of the possibility of such damage.