Refactor apply2const (#2316)

4 files changed, 167 insertions, 63 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 43aa70174..c7dc311b6 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -63,6 +63,8 @@ libcvc4_la_SOURCES = \
 	decision/justification_heuristic.h \
 	preprocessing/passes/apply_substs.cpp \
 	preprocessing/passes/apply_substs.h \
+	preprocessing/passes/apply_to_const.cpp \
+	preprocessing/passes/apply_to_const.h \
 	preprocessing/passes/bv_abstraction.cpp \
 	preprocessing/passes/bv_abstraction.h \
 	preprocessing/passes/bv_ackermann.cpp \
diff --git a/src/preprocessing/passes/apply_to_const.cpp b/src/preprocessing/passes/apply_to_const.cpp
new file mode 100644
index 000000000..bbe4439ec
--- /dev/null
+++ b/src/preprocessing/passes/apply_to_const.cpp
@@ -0,0 +1,108 @@
+/*********************                                                        */
+/*! \file apply_to_const.cpp
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Haniel Barbosa
+ ** 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 ApplyToConst preprocessing pass
+ **
+ ** Rewrites applies to constants
+ **/
+
+#include "preprocessing/passes/apply_to_const.h"
+
+#include "theory/rewriter.h"
+
+namespace CVC4 {
+namespace preprocessing {
+namespace passes {
+
+using namespace CVC4::theory;
+
+ApplyToConst::ApplyToConst(PreprocessingPassContext* preprocContext)
+    : PreprocessingPass(preprocContext, "apply-to-const"){};
+
+Node ApplyToConst::rewriteApplyToConst(TNode n, NodeMap& cache)
+{
+  Trace("rewriteApplyToConst") << "rewriteApplyToConst :: " << n << std::endl;
+
+  if (n.getMetaKind() == kind::metakind::CONSTANT
+      || n.getMetaKind() == kind::metakind::VARIABLE
+      || n.getMetaKind() == kind::metakind::NULLARY_OPERATOR)
+  {
+    return n;
+  }
+
+  if (cache.find(n) != cache.end())
+  {
+    Trace("rewriteApplyToConst") << "in cache :: " << cache[n] << std::endl;
+    return cache[n];
+  }
+
+  if (n.getKind() == kind::APPLY_UF)
+  {
+    if (n.getNumChildren() == 1 && n[0].isConst() && n[0].getType().isInteger())
+    {
+      stringstream ss;
+      ss << n.getOperator() << "_";
+      if (n[0].getConst<Rational>() < 0)
+      {
+        ss << "m" << -n[0].getConst<Rational>();
+      }
+      else
+      {
+        ss << n[0];
+      }
+      Node newvar =
+          NodeManager::currentNM()->mkSkolem(ss.str(),
+                                             n.getType(),
+                                             "rewriteApplyToConst skolem",
+                                             NodeManager::SKOLEM_EXACT_NAME);
+      cache[n] = newvar;
+      Trace("rewriteApplyToConst") << "made :: " << newvar << std::endl;
+      return newvar;
+    }
+    stringstream ss;
+    ss << "The rewrite-apply-to-const preprocessor is currently limited;\n"
+       << "it only works if all function symbols are unary and with Integer\n"
+       << "domain, and all applications are to integer values.\n"
+       << "Found application: " << n;
+    Unhandled(ss.str());
+  }
+
+  NodeBuilder<> builder(n.getKind());
+  if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
+  {
+    builder << n.getOperator();
+  }
+  for (unsigned i = 0; i < n.getNumChildren(); ++i)
+  {
+    builder << rewriteApplyToConst(n[i], cache);
+  }
+  Node rewr = builder;
+  cache[n] = rewr;
+  Trace("rewriteApplyToConst") << "built :: " << rewr << std::endl;
+  return rewr;
+}
+
+PreprocessingPassResult ApplyToConst::applyInternal(
+    AssertionPipeline* assertionsToPreprocess)
+{
+  NodeMap cache;
+  for (unsigned i = 0, size = assertionsToPreprocess->size(); i < size; ++i)
+  {
+    assertionsToPreprocess->replace(i,
+                                    Rewriter::rewrite(rewriteApplyToConst(
+                                        (*assertionsToPreprocess)[i], cache)));
+  }
+  return PreprocessingPassResult::NO_CONFLICT;
+}
+
+}  // namespace passes
+}  // namespace preprocessing
+}  // namespace CVC4
diff --git a/src/preprocessing/passes/apply_to_const.h b/src/preprocessing/passes/apply_to_const.h
new file mode 100644
index 000000000..9d5072023
--- /dev/null
+++ b/src/preprocessing/passes/apply_to_const.h
@@ -0,0 +1,51 @@
+/*********************                                                        */
+/*! \file apply_to_const.h
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Haniel Barbosa
+ ** 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 ApplyToConst preprocessing pass
+ **
+ ** Rewrites applies to constants
+ **/
+
+#include "cvc4_private.h"
+
+#ifndef __CVC4__PREPROCESSING__PASSES__APPLY_TO_CONST_H
+#define __CVC4__PREPROCESSING__PASSES__APPLY_TO_CONST_H
+
+#include <unordered_map>
+
+#include "expr/node.h"
+#include "preprocessing/preprocessing_pass.h"
+#include "preprocessing/preprocessing_pass_context.h"
+
+namespace CVC4 {
+namespace preprocessing {
+namespace passes {
+
+using NodeMap = std::unordered_map<Node, Node, NodeHashFunction>;
+
+class ApplyToConst : public PreprocessingPass
+{
+ public:
+  ApplyToConst(PreprocessingPassContext* preprocContext);
+
+ protected:
+  PreprocessingPassResult applyInternal(
+      AssertionPipeline* assertionsToPreprocess) override;
+
+ private:
+  Node rewriteApplyToConst(TNode n, NodeMap& cache);
+};
+
+}  // namespace passes
+}  // namespace preprocessing
+}  // namespace CVC4
+
+#endif /* __CVC4__PREPROCESSING__PASSES__APPLY_TO_CONST_H */
diff --git a/src/smt/smt_engine.cpp b/src/smt/smt_engine.cpp
index db4efe89f..41b113b94 100644
--- a/src/smt/smt_engine.cpp
+++ b/src/smt/smt_engine.cpp
@@ -70,6 +70,7 @@
 #include "options/theory_options.h"
 #include "options/uf_options.h"
 #include "preprocessing/passes/apply_substs.h"
+#include "preprocessing/passes/apply_to_const.h"
 #include "preprocessing/passes/bool_to_bv.h"
 #include "preprocessing/passes/bv_abstraction.h"
 #include "preprocessing/passes/bv_ackermann.h"
@@ -897,66 +898,6 @@ public:
     return retval;
   }
 
-  NodeToNodeHashMap d_rewriteApplyToConstCache;
-  Node rewriteApplyToConst(TNode n) {
-    Trace("rewriteApplyToConst") << "rewriteApplyToConst :: " << n << std::endl;
-
-    if(n.getMetaKind() == kind::metakind::CONSTANT ||
-       n.getMetaKind() == kind::metakind::VARIABLE ||
-       n.getMetaKind() == kind::metakind::NULLARY_OPERATOR)
-    {
-      return n;
-    }
-
-    if(d_rewriteApplyToConstCache.find(n) != d_rewriteApplyToConstCache.end()) {
-      Trace("rewriteApplyToConst") << "in cache :: "
-                                   << d_rewriteApplyToConstCache[n]
-                                   << std::endl;
-      return d_rewriteApplyToConstCache[n];
-    }
-
-    if(n.getKind() == kind::APPLY_UF) {
-      if(n.getNumChildren() == 1 && n[0].isConst() &&
-         n[0].getType().isInteger())
-      {
-        stringstream ss;
-        ss << n.getOperator() << "_";
-        if(n[0].getConst<Rational>() < 0) {
-          ss << "m" << -n[0].getConst<Rational>();
-        } else {
-          ss << n[0];
-        }
-        Node newvar = NodeManager::currentNM()->mkSkolem(
-            ss.str(), n.getType(), "rewriteApplyToConst skolem",
-            NodeManager::SKOLEM_EXACT_NAME);
-        d_rewriteApplyToConstCache[n] = newvar;
-        Trace("rewriteApplyToConst") << "made :: " << newvar << std::endl;
-        return newvar;
-      } else {
-        stringstream ss;
-        ss << "The rewrite-apply-to-const preprocessor is currently limited;"
-           << std::endl
-           << "it only works if all function symbols are unary and with Integer"
-           << std::endl
-           << "domain, and all applications are to integer values." << std::endl
-           << "Found application: " << n;
-        Unhandled(ss.str());
-      }
-    }
-
-    NodeBuilder<> builder(n.getKind());
-    if(n.getMetaKind() == kind::metakind::PARAMETERIZED) {
-      builder << n.getOperator();
-    }
-    for(unsigned i = 0; i < n.getNumChildren(); ++i) {
-      builder << rewriteApplyToConst(n[i]);
-    }
-    Node rewr = builder;
-    d_rewriteApplyToConstCache[n] = rewr;
-    Trace("rewriteApplyToConst") << "built :: " << rewr << std::endl;
-    return rewr;
-  }
-
   void addUseTheoryListListener(TheoryEngine* theoryEngine){
     Options& nodeManagerOptions = NodeManager::currentNM()->getOptions();
     d_listenerRegistrations->add(
@@ -2717,6 +2658,8 @@ void SmtEnginePrivate::finishInit()
   // actually assembling preprocessing pipelines).
   std::unique_ptr<ApplySubsts> applySubsts(
       new ApplySubsts(d_preprocessingPassContext.get()));
+  std::unique_ptr<ApplyToConst> applyToConst(
+      new ApplyToConst(d_preprocessingPassContext.get()));
   std::unique_ptr<BoolToBV> boolToBv(
       new BoolToBV(d_preprocessingPassContext.get()));
   std::unique_ptr<BvAbstraction> bvAbstract(
@@ -2750,6 +2693,8 @@ void SmtEnginePrivate::finishInit()
       new SepSkolemEmp(d_preprocessingPassContext.get()));
   d_preprocessingPassRegistry.registerPass("apply-substs",
                                            std::move(applySubsts));
+  d_preprocessingPassRegistry.registerPass("apply-to-const",
+                                           std::move(applyToConst));
   d_preprocessingPassRegistry.registerPass("bool-to-bv", std::move(boolToBv));
   d_preprocessingPassRegistry.registerPass("bv-abstraction",
                                            std::move(bvAbstract));
@@ -4476,9 +4421,7 @@ void SmtEnginePrivate::processAssertions() {
   if(options::rewriteApplyToConst()) {
     Chat() << "Rewriting applies to constants..." << endl;
     TimerStat::CodeTimer codeTimer(d_smt.d_stats->d_rewriteApplyToConstTime);
-    for (unsigned i = 0; i < d_assertions.size(); ++ i) {
-      d_assertions[i] = Rewriter::rewrite(rewriteApplyToConst(d_assertions[i]));
-    }
+    d_preprocessingPassRegistry.getPass("apply-to-const")->apply(&d_assertions);
   }
   dumpAssertions("post-rewrite-apply-to-const", d_assertions);