Refactor sep-pre-skolem-emp preprocessing pass

2 files changed, 166 insertions, 0 deletions

diff --git a/src/preprocessing/passes/sep_skolem_emp.cpp b/src/preprocessing/passes/sep_skolem_emp.cpp
new file mode 100644
index 000000000..d79ec8b93
--- /dev/null
+++ b/src/preprocessing/passes/sep_skolem_emp.cpp
@@ -0,0 +1,124 @@
+/**********************/
+/*! \file sep_skolem_emp.cpp
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Andrew Reynolds, Mathias Preiner, Yoni Zohar
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2018 by the authors listed in the file AUTHORS
+ ** in the top-level source directory) and their institutional affiliations.
+ ** All rights reserved.  See the file COPYING in the top-level source
+ ** directory for licensing information.\endverbatim
+ **
+ ** \brief The sep-pre-skolem-emp preprocessing pass
+ **
+ **/
+
+#include "preprocessing/passes/sep_skolem_emp.h"
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "expr/node.h"
+#include "theory/quantifiers/quant_util.h"
+#include "theory/rewriter.h"
+#include "theory/theory.h"
+
+namespace CVC4 {
+namespace preprocessing {
+namespace passes {
+
+using namespace CVC4::theory;
+
+namespace {
+
+Node preSkolemEmp(Node n,
+                         bool pol,
+                         std::map<bool, std::map<Node, Node>>& visited)
+{
+  std::map<Node, Node>::iterator it = visited[pol].find(n);
+  if (it == visited[pol].end())
+  {
+    Trace("sep-preprocess") << "Pre-skolem emp " << n << " with pol " << pol
+                            << std::endl;
+    Node ret = n;
+    if (n.getKind() == kind::SEP_EMP)
+    {
+      if (!pol)
+      {
+        TypeNode tnx = n[0].getType();
+        TypeNode tny = n[1].getType();
+        Node x = NodeManager::currentNM()->mkSkolem(
+            "ex", tnx, "skolem location for negated emp");
+        Node y = NodeManager::currentNM()->mkSkolem(
+            "ey", tny, "skolem data for negated emp");
+        return NodeManager::currentNM()
+            ->mkNode(kind::SEP_STAR,
+                     NodeManager::currentNM()->mkNode(kind::SEP_PTO, x, y),
+                     NodeManager::currentNM()->mkConst(true))
+            .negate();
+      }
+    }
+    else if (n.getKind() != kind::FORALL && n.getNumChildren() > 0)
+    {
+      std::vector<Node> children;
+      bool childChanged = false;
+      if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
+      {
+        children.push_back(n.getOperator());
+      }
+      for (unsigned i = 0; i < n.getNumChildren(); i++)
+      {
+        bool newPol, newHasPol;
+        QuantPhaseReq::getPolarity(n, i, true, pol, newHasPol, newPol);
+        Node nc = n[i];
+        if (newHasPol)
+        {
+          nc = preSkolemEmp(n[i], newPol, visited);
+          childChanged = childChanged || nc != n[i];
+        }
+        children.push_back(nc);
+      }
+      if (childChanged)
+      {
+        return NodeManager::currentNM()->mkNode(n.getKind(), children);
+      }
+    }
+    visited[pol][n] = ret;
+    return n;
+  }
+  else
+  {
+    return it->second;
+  }
+}
+
+}  // namespace
+
+SepSkolemEmp::SepSkolemEmp(PreprocessingPassContext* preprocContext)
+    : PreprocessingPass(preprocContext, "sep-skolem-emp"){};
+
+PreprocessingPassResult SepSkolemEmp::applyInternal(
+    AssertionPipeline* assertionsToPreprocess)
+{
+  std::map<bool, std::map<Node, Node>> visited;
+  for (unsigned i = 0; i < assertionsToPreprocess->size(); ++i)
+  {
+    Node prev = (*assertionsToPreprocess)[i];
+    bool pol = true;
+    Node next = preSkolemEmp(prev, pol, visited);
+    if (next != prev)
+    {
+      assertionsToPreprocess->replace(i, Rewriter::rewrite(next));
+      Trace("sep-preprocess") << "*** Preprocess sep " << prev << endl;
+      Trace("sep-preprocess") << "   ...got " << (*assertionsToPreprocess)[i]
+                              << endl;
+    }
+    visited.clear();
+  }
+  return PreprocessingPassResult::NO_CONFLICT;
+}
+
+}  // namespace passes
+}  // namespace preprocessing
+}  // namespace CVC4
diff --git a/src/preprocessing/passes/sep_skolem_emp.h b/src/preprocessing/passes/sep_skolem_emp.h
new file mode 100644
index 000000000..4a3dba6b8
--- /dev/null
+++ b/src/preprocessing/passes/sep_skolem_emp.h
@@ -0,0 +1,42 @@
+/*********************                                                        */
+/*! \file sep_skolem_emp.h
+ ** \verbatim
+ ** Top contributors (to current version):
+ ** Andrew Reynolds, Mathias Preiner, Yoni Zohar
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2018 by the authors listed in the file AUTHORS
+ ** in the top-level source directory) and their institutional affiliations.
+ ** All rights reserved.  See the file COPYING in the top-level source
+ ** directory for licensing information.\endverbatim
+ **
+ ** \brief The sep-pre-skolem-emp eprocessing pass
+ **
+ **/
+
+#include "cvc4_private.h"
+
+#ifndef __CVC4__PREPROCESSING__PASSES__SEP_SKOLEM_EMP_H
+#define __CVC4__PREPROCESSING__PASSES__SEP_SKOLEM_EMP_H
+
+#include "preprocessing/preprocessing_pass.h"
+#include "preprocessing/preprocessing_pass_context.h"
+
+namespace CVC4 {
+namespace preprocessing {
+namespace passes {
+
+class SepSkolemEmp : public PreprocessingPass
+{
+ public:
+  SepSkolemEmp(PreprocessingPassContext* preprocContext);
+
+ protected:
+  PreprocessingPassResult applyInternal(
+      AssertionPipeline* assertionsToPreprocess) override;
+};
+
+}  // namespace passes
+}  // namespace preprocessing
+}  // namespace CVC4
+
+#endif /* __CVC4__PREPROCESSING__PASSES__SEP_SKOLEM_EMP_H */