From 23374b9d7fe9363165c99fbbddfd7591302a3431 Mon Sep 17 00:00:00 2001
From: Alex Ozdemir <aozdemir@hmc.edu>
Date: Mon, 14 Jan 2019 10:53:31 -0800
Subject: ClausalBitvectorProof (#2786)

* [DRAT] ClausalBitvectorProof

Created a class, `ClausalBitvectorProof`, which represents a bitvector
proof of UNSAT using an underlying clausal technique (DRAT, LRAT, etc)

It fits into the `BitvectorProof` class hierarchy like this:

```
              BitvectorProof
              /            \
             /              \
ClausalBitvectorProof  ResolutionBitvectorProof
```

This change is a painful one because all of the following BV subsystems
referenced ResolutionBitvectorProof (subsequently RBVP) or
BitvectorProof (subsequently BVP):
   * CnfStream
   * SatSolver (specifically the BvSatSolver)
   * CnfProof
   * TheoryProof
   * TheoryBV
   * Both bitblasters

And in particular, ResolutionBitvectorProof, the CnfStream, and the
SatSolvers were tightly coupled.

This means that references to and interactions with (R)BVP were
pervasive.

Nevertheless, an SMT developer must persist.

The change summary:
  * Create a subclass of BVP, called ClausalBitvectorProof, which has
    most methods stubbed out.
  * Make a some modifications to BVP and ResolutionBitvectorProof as the
    natural division of labor between the different classes becomes
    clear.
  * Go through all the components in the first list and try to figure
    out which kind of BVP they should **actually** be interacting with,
    and how. Make tweaks accordingly.
  * Add a hook from CryptoMinisat which pipes the produced DRAT proof
    into the new ClausalBitvectorProof.
  * Add a debug statement to ClausalBitvectorProof which parses and
    prints that DRAT proof, for testing purposes.

Test:
  * `make check` to verify that we didn't break any old stuff, including
    lazy BB, and eager BB when using bvminisat.
  * `cvc4 --dump-proofs --bv-sat-solver=cryptominisat --bitblast=eager
  -d bv::clausal test/regress/regress0/bv/ackermann2.smt2`, and see that
     1. It crashed with "Unimplemented"
     2. Right before that it prints out the (textual) DRAT proof.

* Remove 2 unneeded methods

* Missed a rename

* Typos

Thanks Andres!

Co-Authored-By: alex-ozdemir <aozdemir@hmc.edu>

* Address Andres comments

* Reorder members of TBitblaster
---
 src/theory/bv/bv_subtheory.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'src/theory/bv/bv_subtheory.h')

diff --git a/src/theory/bv/bv_subtheory.h b/src/theory/bv/bv_subtheory.h
index 31c542e0b..e2b649841 100644
--- a/src/theory/bv/bv_subtheory.h
+++ b/src/theory/bv/bv_subtheory.h
@@ -26,7 +26,7 @@
 namespace CVC4 {
 
 namespace proof {
-class ResolutionBitVectorProof;
+class BitVectorProof;
 }
 
 namespace theory {
@@ -93,7 +93,7 @@ class SubtheorySolver {
     return res;
   }
   virtual void assertFact(TNode fact) { d_assertionQueue.push_back(fact); }
-  virtual void setProofLog(proof::ResolutionBitVectorProof* bvp) {}
+  virtual void setProofLog(proof::BitVectorProof* bvp) {}
   AssertionQueue::const_iterator assertionsBegin() {
     return d_assertionQueue.begin();
   }
-- 
cgit v1.2.3