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GCC Code Coverage Report

Directory:	.		Exec	Total	Coverage
File:	src/expr/skolem_manager.cpp	Lines:	161	171	94.2 %
Date:	2021-08-11	Branches:	319	781	40.8 %


/******************************************************************************
 * Top contributors (to current version):
 *   Andrew Reynolds, Aina Niemetz
 *
 * This file is part of the cvc5 project.
 *
 * Copyright (c) 2009-2021 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.
 * ****************************************************************************
 *
 * Implementation of skolem manager class.
 */

#include "expr/skolem_manager.h"

#include <sstream>

#include "expr/attribute.h"
#include "expr/bound_var_manager.h"
#include "expr/node_algorithm.h"

using namespace cvc5::kind;

namespace cvc5 {

// Attributes are global maps from Nodes to data. Thus, note that these could
// be implemented as internal maps in SkolemManager.
struct WitnessFormAttributeId
{
};
typedef expr::Attribute<WitnessFormAttributeId, Node> WitnessFormAttribute;

struct SkolemFormAttributeId
{
};
typedef expr::Attribute<SkolemFormAttributeId, Node> SkolemFormAttribute;

struct OriginalFormAttributeId
{
};
typedef expr::Attribute<OriginalFormAttributeId, Node> OriginalFormAttribute;

const char* toString(SkolemFunId id)
{
  switch (id)
  {
    case SkolemFunId::DIV_BY_ZERO: return "DIV_BY_ZERO";
    case SkolemFunId::INT_DIV_BY_ZERO: return "INT_DIV_BY_ZERO";
    case SkolemFunId::MOD_BY_ZERO: return "MOD_BY_ZERO";
    case SkolemFunId::SQRT: return "SQRT";
    case SkolemFunId::SELECTOR_WRONG: return "SELECTOR_WRONG";
    case SkolemFunId::SHARED_SELECTOR: return "SHARED_SELECTOR";
    case SkolemFunId::SEQ_NTH_OOB: return "SEQ_NTH_OOB";
    case SkolemFunId::RE_UNFOLD_POS_COMPONENT: return "RE_UNFOLD_POS_COMPONENT";
    default: return "?";
  }
}

std::ostream& operator<<(std::ostream& out, SkolemFunId id)
{
  out << toString(id);
  return out;
}

Node SkolemManager::mkSkolem(Node v,
                             Node pred,
                             const std::string& prefix,
                             const std::string& comment,
                             int flags,
                             ProofGenerator* pg)
{
  // We do not currently insist that pred does not contain witness terms
  Assert(v.getKind() == BOUND_VARIABLE);
  // make the witness term
  NodeManager* nm = NodeManager::currentNM();
  Node bvl = nm->mkNode(BOUND_VAR_LIST, v);
  // Make the witness term, where notice that pred may contain skolems. We do
  // not recursively convert pred to witness form, since witness terms should
  // be treated as opaque. Moreover, the use of witness forms leads to
  // variable shadowing issues in e.g. skolemization.
  Node w = nm->mkNode(WITNESS, bvl, pred);
  // store the mapping to proof generator if it exists
  if (pg != nullptr)
  {
    // We cache based on the existential of the original predicate
    Node q = nm->mkNode(EXISTS, bvl, pred);
    // Notice this may overwrite an existing proof generator. This does not
    // matter since either should be able to prove q.
    d_gens[q] = pg;
  }
  Node k = mkSkolemInternal(w, prefix, comment, flags);
  // set witness form attribute for k
  WitnessFormAttribute wfa;
  k.setAttribute(wfa, w);
  Trace("sk-manager-skolem")
      << "skolem: " << k << " witness " << w << std::endl;
  return k;
}

Node SkolemManager::mkSkolemize(Node q,
                                std::vector<Node>& skolems,
                                const std::string& prefix,
                                const std::string& comment,
                                int flags,
                                ProofGenerator* pg)
{
  Trace("sk-manager-debug") << "mkSkolemize " << q << std::endl;
  Assert(q.getKind() == EXISTS);
  Node currQ = q;
  for (const Node& av : q[0])
  {
    Assert(currQ.getKind() == EXISTS && av == currQ[0][0]);
    // currQ is updated to the result of skolemizing its first variable in
    // the method below.
    Node sk = skolemize(currQ, currQ, prefix, comment, flags);
    Trace("sk-manager-debug")
        << "made skolem " << sk << " for " << av << std::endl;
    skolems.push_back(sk);
  }
  if (pg != nullptr)
  {
    // Same as above, this may overwrite an existing proof generator
    d_gens[q] = pg;
  }
  Trace("sk-manager-debug") << "...mkSkolemize returns " << currQ << std::endl;
  return currQ;
}

Node SkolemManager::skolemize(Node q,
                              Node& qskolem,
                              const std::string& prefix,
                              const std::string& comment,
                              int flags)
{
  Assert(q.getKind() == EXISTS);
  Node v;
  std::vector<Node> ovars;
  Trace("sk-manager-debug") << "mkSkolemize..." << std::endl;
  NodeManager* nm = NodeManager::currentNM();
  for (const Node& av : q[0])
  {
    if (v.isNull())
    {
      v = av;
      continue;
    }
    ovars.push_back(av);
  }
  Assert(!v.isNull());
  // make the predicate with one variable stripped off
  Node pred = q[1];
  Trace("sk-manager-debug") << "make exists predicate" << std::endl;
  if (!ovars.empty())
  {
    // keeps the same variables
    Node bvl = nm->mkNode(BOUND_VAR_LIST, ovars);
    // update the predicate
    pred = nm->mkNode(EXISTS, bvl, pred);
  }
  Trace("sk-manager-debug") << "call sub mkSkolem" << std::endl;
  // don't use a proof generator, since this may be an intermediate, partially
  // skolemized formula.
  Node k = mkSkolem(v, pred, prefix, comment, flags, nullptr);
  Assert(k.getType() == v.getType());
  TNode tv = v;
  TNode tk = k;
  Trace("sk-manager-debug")
      << "qskolem apply " << tv << " -> " << tk << " to " << pred << std::endl;
  // the quantified formula with one step of skolemization
  qskolem = pred.substitute(tv, tk);
  Trace("sk-manager-debug") << "qskolem done substitution" << std::endl;
  return k;
}

Node SkolemManager::mkPurifySkolem(Node t,
                                   const std::string& prefix,
                                   const std::string& comment,
                                   int flags)
{
  Node to = getOriginalForm(t);
  // We do not currently insist that to does not contain witness terms

  Node k = mkSkolemInternal(to, prefix, comment, flags);
  // set original form attribute for k
  OriginalFormAttribute ofa;
  k.setAttribute(ofa, to);

  Trace("sk-manager-skolem")
      << "skolem: " << k << " purify " << to << std::endl;
  return k;
}

Node SkolemManager::mkSkolemFunction(SkolemFunId id,
                                     TypeNode tn,
                                     Node cacheVal,
                                     int flags)
{
  std::tuple<SkolemFunId, TypeNode, Node> key(id, tn, cacheVal);
  std::map<std::tuple<SkolemFunId, TypeNode, Node>, Node>::iterator it =
      d_skolemFuns.find(key);
  if (it == d_skolemFuns.end())
  {
    NodeManager* nm = NodeManager::currentNM();
    std::stringstream ss;
    ss << "SKOLEM_FUN_" << id;
    Node k = nm->mkSkolem(ss.str(), tn, "an internal skolem function", flags);
    d_skolemFuns[key] = k;
    d_skolemFunMap[k] = key;
    return k;
  }
  return it->second;
}

Node SkolemManager::mkSkolemFunction(SkolemFunId id,
                                     TypeNode tn,
                                     const std::vector<Node>& cacheVals,
                                     int flags)
{
  Assert(cacheVals.size() > 1);
  Node cacheVal = NodeManager::currentNM()->mkNode(SEXPR, cacheVals);
  return mkSkolemFunction(id, tn, cacheVal, flags);
}

bool SkolemManager::isSkolemFunction(Node k,
                                     SkolemFunId& id,
                                     Node& cacheVal) const
{
  std::map<Node, std::tuple<SkolemFunId, TypeNode, Node>>::const_iterator it =
      d_skolemFunMap.find(k);
  if (it == d_skolemFunMap.end())
  {
    return false;
  }
  id = std::get<0>(it->second);
  cacheVal = std::get<2>(it->second);
  return true;
}

Node SkolemManager::mkDummySkolem(const std::string& prefix,
                                  const TypeNode& type,
                                  const std::string& comment,
                                  int flags)
{
  return NodeManager::currentNM()->mkSkolem(prefix, type, comment, flags);
}

ProofGenerator* SkolemManager::getProofGenerator(Node t) const
{
  std::map<Node, ProofGenerator*>::const_iterator it = d_gens.find(t);
  if (it != d_gens.end())
  {
    return it->second;
  }
  return nullptr;
}

Node SkolemManager::getWitnessForm(Node k)
{
  Assert(k.getKind() == SKOLEM);
  // simply look up the witness form for k via an attribute
  WitnessFormAttribute wfa;
  return k.getAttribute(wfa);
}

Node SkolemManager::getOriginalForm(Node n)
{
  if (n.isNull())
  {
    return n;
  }
  Trace("sk-manager-debug")
      << "SkolemManager::getOriginalForm " << n << std::endl;
  OriginalFormAttribute ofa;
  NodeManager* nm = NodeManager::currentNM();
  std::unordered_map<TNode, Node> visited;
  std::unordered_map<TNode, Node>::iterator it;
  std::vector<TNode> visit;
  TNode cur;
  visit.push_back(n);
  do
  {
    cur = visit.back();
    visit.pop_back();
    it = visited.find(cur);

    if (it == visited.end())
    {
      if (cur.hasAttribute(ofa))
      {
        visited[cur] = cur.getAttribute(ofa);
      }
      else
      {
        visited[cur] = Node::null();
        visit.push_back(cur);
        if (cur.getMetaKind() == metakind::PARAMETERIZED)
        {
          visit.push_back(cur.getOperator());
        }
        for (const Node& cn : cur)
        {
          visit.push_back(cn);
        }
      }
    }
    else if (it->second.isNull())
    {
      Node ret = cur;
      bool childChanged = false;
      std::vector<Node> children;
      if (cur.getMetaKind() == metakind::PARAMETERIZED)
      {
        it = visited.find(cur.getOperator());
        Assert(it != visited.end());
        Assert(!it->second.isNull());
        childChanged = childChanged || cur.getOperator() != it->second;
        children.push_back(it->second);
      }
      for (const Node& cn : cur)
      {
        it = visited.find(cn);
        Assert(it != visited.end());
        Assert(!it->second.isNull());
        childChanged = childChanged || cn != it->second;
        children.push_back(it->second);
      }
      if (childChanged)
      {
        ret = nm->mkNode(cur.getKind(), children);
      }
      cur.setAttribute(ofa, ret);
      visited[cur] = ret;
    }
  } while (!visit.empty());
  Assert(visited.find(n) != visited.end());
  Assert(!visited.find(n)->second.isNull());
  Trace("sk-manager-debug") << "..return " << visited[n] << std::endl;
  return visited[n];
}

Node SkolemManager::mkSkolemInternal(Node w,
                                     const std::string& prefix,
                                     const std::string& comment,
                                     int flags)
{
  // note that witness, original forms are independent, but share skolems
  NodeManager* nm = NodeManager::currentNM();
  // w is not necessarily a witness term
  SkolemFormAttribute sfa;
  Node k;
  // could already have a skolem if we used w already
  if (w.hasAttribute(sfa))
  {
    return w.getAttribute(sfa);
  }
  // make the new skolem
  if (flags & NodeManager::SKOLEM_BOOL_TERM_VAR)
  {
    Assert (w.getType().isBoolean());
    k = nm->mkBooleanTermVariable();
  }
  else
  {
    k = nm->mkSkolem(prefix, w.getType(), comment, flags);
  }
  // set skolem form attribute for w
  w.setAttribute(sfa, k);
  Trace("sk-manager") << "SkolemManager::mkSkolem: " << k << " : " << w
                      << std::endl;
  return k;
}

}  // namespace cvc5


Generated by: GCOVR (Version 3.2)

Line	Exec	Source
1		/******************************************************************************
2		* Top contributors (to current version):
3		* Andrew Reynolds, Aina Niemetz
4		*
5		* This file is part of the cvc5 project.
6		*
7		* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
8		* in the top-level source directory and their institutional affiliations.
9		* All rights reserved. See the file COPYING in the top-level source
10		* directory for licensing information.
11		* ****************************************************************************
12		*
13		* Implementation of skolem manager class.
14		*/
15
16		#include "expr/skolem_manager.h"
17
18		#include <sstream>
19
20		#include "expr/attribute.h"
21		#include "expr/bound_var_manager.h"
22		#include "expr/node_algorithm.h"
23
24		using namespace cvc5::kind;
25
26		namespace cvc5 {
27
28		// Attributes are global maps from Nodes to data. Thus, note that these could
29		// be implemented as internal maps in SkolemManager.
30		struct WitnessFormAttributeId
31		{
32		};
33		typedef expr::Attribute<WitnessFormAttributeId, Node> WitnessFormAttribute;
34
35		struct SkolemFormAttributeId
36		{
37		};
38		typedef expr::Attribute<SkolemFormAttributeId, Node> SkolemFormAttribute;
39
40		struct OriginalFormAttributeId
41		{
42		};
43		typedef expr::Attribute<OriginalFormAttributeId, Node> OriginalFormAttribute;
44
45	3522	const char* toString(SkolemFunId id)
46		{
47	3522	switch (id)
48		{
49	81	case SkolemFunId::DIV_BY_ZERO: return "DIV_BY_ZERO";
50	73	case SkolemFunId::INT_DIV_BY_ZERO: return "INT_DIV_BY_ZERO";
51	32	case SkolemFunId::MOD_BY_ZERO: return "MOD_BY_ZERO";
52	11	case SkolemFunId::SQRT: return "SQRT";
53	649	case SkolemFunId::SELECTOR_WRONG: return "SELECTOR_WRONG";
54	2022	case SkolemFunId::SHARED_SELECTOR: return "SHARED_SELECTOR";
55	23	case SkolemFunId::SEQ_NTH_OOB: return "SEQ_NTH_OOB";
56	631	case SkolemFunId::RE_UNFOLD_POS_COMPONENT: return "RE_UNFOLD_POS_COMPONENT";
57		default: return "?";
58		}
59		}
60
61	3522	std::ostream& operator<<(std::ostream& out, SkolemFunId id)
62		{
63	3522	out << toString(id);
64	3522	return out;
65		}
66
67	4117	Node SkolemManager::mkSkolem(Node v,
68		Node pred,
69		const std::string& prefix,
70		const std::string& comment,
71		int flags,
72		ProofGenerator* pg)
73		{
74		// We do not currently insist that pred does not contain witness terms
75	4117	Assert(v.getKind() == BOUND_VARIABLE);
76		// make the witness term
77	4117	NodeManager* nm = NodeManager::currentNM();
78	8234	Node bvl = nm->mkNode(BOUND_VAR_LIST, v);
79		// Make the witness term, where notice that pred may contain skolems. We do
80		// not recursively convert pred to witness form, since witness terms should
81		// be treated as opaque. Moreover, the use of witness forms leads to
82		// variable shadowing issues in e.g. skolemization.
83	8234	Node w = nm->mkNode(WITNESS, bvl, pred);
84		// store the mapping to proof generator if it exists
85	4117	if (pg != nullptr)
86		{
87		// We cache based on the existential of the original predicate
88	3344	Node q = nm->mkNode(EXISTS, bvl, pred);
89		// Notice this may overwrite an existing proof generator. This does not
90		// matter since either should be able to prove q.
91	1672	d_gens[q] = pg;
92		}
93	4117	Node k = mkSkolemInternal(w, prefix, comment, flags);
94		// set witness form attribute for k
95		WitnessFormAttribute wfa;
96	4117	k.setAttribute(wfa, w);
97	8234	Trace("sk-manager-skolem")
98	4117	<< "skolem: " << k << " witness " << w << std::endl;
99	8234	return k;
100		}
101
102	737	Node SkolemManager::mkSkolemize(Node q,
103		std::vector<Node>& skolems,
104		const std::string& prefix,
105		const std::string& comment,
106		int flags,
107		ProofGenerator* pg)
108		{
109	737	Trace("sk-manager-debug") << "mkSkolemize " << q << std::endl;
110	737	Assert(q.getKind() == EXISTS);
111	737	Node currQ = q;
112	1866	for (const Node& av : q[0])
113		{
114	1129	Assert(currQ.getKind() == EXISTS && av == currQ[0][0]);
115		// currQ is updated to the result of skolemizing its first variable in
116		// the method below.
117	2258	Node sk = skolemize(currQ, currQ, prefix, comment, flags);
118	2258	Trace("sk-manager-debug")
119	1129	<< "made skolem " << sk << " for " << av << std::endl;
120	1129	skolems.push_back(sk);
121		}
122	737	if (pg != nullptr)
123		{
124		// Same as above, this may overwrite an existing proof generator
125		d_gens[q] = pg;
126		}
127	737	Trace("sk-manager-debug") << "...mkSkolemize returns " << currQ << std::endl;
128	737	return currQ;
129		}
130
131	1129	Node SkolemManager::skolemize(Node q,
132		Node& qskolem,
133		const std::string& prefix,
134		const std::string& comment,
135		int flags)
136		{
137	1129	Assert(q.getKind() == EXISTS);
138	2258	Node v;
139	2258	std::vector<Node> ovars;
140	1129	Trace("sk-manager-debug") << "mkSkolemize..." << std::endl;
141	1129	NodeManager* nm = NodeManager::currentNM();
142	4853	for (const Node& av : q[0])
143		{
144	5982	if (v.isNull())
145		{
146	1129	v = av;
147	1129	continue;
148		}
149	3724	ovars.push_back(av);
150		}
151	1129	Assert(!v.isNull());
152		// make the predicate with one variable stripped off
153	2258	Node pred = q[1];
154	1129	Trace("sk-manager-debug") << "make exists predicate" << std::endl;
155	1129	if (!ovars.empty())
156		{
157		// keeps the same variables
158	784	Node bvl = nm->mkNode(BOUND_VAR_LIST, ovars);
159		// update the predicate
160	392	pred = nm->mkNode(EXISTS, bvl, pred);
161		}
162	1129	Trace("sk-manager-debug") << "call sub mkSkolem" << std::endl;
163		// don't use a proof generator, since this may be an intermediate, partially
164		// skolemized formula.
165	1129	Node k = mkSkolem(v, pred, prefix, comment, flags, nullptr);
166	1129	Assert(k.getType() == v.getType());
167	2258	TNode tv = v;
168	2258	TNode tk = k;
169	2258	Trace("sk-manager-debug")
170	1129	<< "qskolem apply " << tv << " -> " << tk << " to " << pred << std::endl;
171		// the quantified formula with one step of skolemization
172	1129	qskolem = pred.substitute(tv, tk);
173	1129	Trace("sk-manager-debug") << "qskolem done substitution" << std::endl;
174	2258	return k;
175		}
176
177	53851	Node SkolemManager::mkPurifySkolem(Node t,
178		const std::string& prefix,
179		const std::string& comment,
180		int flags)
181		{
182	107702	Node to = getOriginalForm(t);
183		// We do not currently insist that to does not contain witness terms
184
185	53851	Node k = mkSkolemInternal(to, prefix, comment, flags);
186		// set original form attribute for k
187		OriginalFormAttribute ofa;
188	53851	k.setAttribute(ofa, to);
189
190	107702	Trace("sk-manager-skolem")
191	53851	<< "skolem: " << k << " purify " << to << std::endl;
192	107702	return k;
193		}
194
195	7474	Node SkolemManager::mkSkolemFunction(SkolemFunId id,
196		TypeNode tn,
197		Node cacheVal,
198		int flags)
199		{
200	14948	std::tuple<SkolemFunId, TypeNode, Node> key(id, tn, cacheVal);
201		std::map<std::tuple<SkolemFunId, TypeNode, Node>, Node>::iterator it =
202	7474	d_skolemFuns.find(key);
203	7474	if (it == d_skolemFuns.end())
204		{
205	3522	NodeManager* nm = NodeManager::currentNM();
206	7044	std::stringstream ss;
207	3522	ss << "SKOLEM_FUN_" << id;
208	7044	Node k = nm->mkSkolem(ss.str(), tn, "an internal skolem function", flags);
209	3522	d_skolemFuns[key] = k;
210	3522	d_skolemFunMap[k] = key;
211	3522	return k;
212		}
213	3952	return it->second;
214		}
215
216	818	Node SkolemManager::mkSkolemFunction(SkolemFunId id,
217		TypeNode tn,
218		const std::vector<Node>& cacheVals,
219		int flags)
220		{
221	818	Assert(cacheVals.size() > 1);
222	1636	Node cacheVal = NodeManager::currentNM()->mkNode(SEXPR, cacheVals);
223	1636	return mkSkolemFunction(id, tn, cacheVal, flags);
224		}
225
226		bool SkolemManager::isSkolemFunction(Node k,
227		SkolemFunId& id,
228		Node& cacheVal) const
229		{
230		std::map<Node, std::tuple<SkolemFunId, TypeNode, Node>>::const_iterator it =
231		d_skolemFunMap.find(k);
232		if (it == d_skolemFunMap.end())
233		{
234		return false;
235		}
236		id = std::get<0>(it->second);
237		cacheVal = std::get<2>(it->second);
238		return true;
239		}
240
241	117264	Node SkolemManager::mkDummySkolem(const std::string& prefix,
242		const TypeNode& type,
243		const std::string& comment,
244		int flags)
245		{
246	117264	return NodeManager::currentNM()->mkSkolem(prefix, type, comment, flags);
247		}
248
249	60	ProofGenerator* SkolemManager::getProofGenerator(Node t) const
250		{
251	60	std::map<Node, ProofGenerator*>::const_iterator it = d_gens.find(t);
252	60	if (it != d_gens.end())
253		{
254		return it->second;
255		}
256	60	return nullptr;
257		}
258
259	1737	Node SkolemManager::getWitnessForm(Node k)
260		{
261	1737	Assert(k.getKind() == SKOLEM);
262		// simply look up the witness form for k via an attribute
263		WitnessFormAttribute wfa;
264	1737	return k.getAttribute(wfa);
265		}
266
267	233863	Node SkolemManager::getOriginalForm(Node n)
268		{
269	233863	if (n.isNull())
270		{
271	3	return n;
272		}
273	467720	Trace("sk-manager-debug")
274	233860	<< "SkolemManager::getOriginalForm " << n << std::endl;
275		OriginalFormAttribute ofa;
276	233860	NodeManager* nm = NodeManager::currentNM();
277	467720	std::unordered_map<TNode, Node> visited;
278	233860	std::unordered_map<TNode, Node>::iterator it;
279	467720	std::vector<TNode> visit;
280	467720	TNode cur;
281	233860	visit.push_back(n);
282	600282	do
283		{
284	834142	cur = visit.back();
285	834142	visit.pop_back();
286	834142	it = visited.find(cur);
287
288	834142	if (it == visited.end())
289		{
290	557284	if (cur.hasAttribute(ofa))
291		{
292	359740	visited[cur] = cur.getAttribute(ofa);
293		}
294		else
295		{
296	197544	visited[cur] = Node::null();
297	197544	visit.push_back(cur);
298	197544	if (cur.getMetaKind() == metakind::PARAMETERIZED)
299		{
300	27435	visit.push_back(cur.getOperator());
301		}
302	572847	for (const Node& cn : cur)
303		{
304	375303	visit.push_back(cn);
305		}
306		}
307		}
308	276858	else if (it->second.isNull())
309		{
310	395088	Node ret = cur;
311	197544	bool childChanged = false;
312	395088	std::vector<Node> children;
313	197544	if (cur.getMetaKind() == metakind::PARAMETERIZED)
314		{
315	27435	it = visited.find(cur.getOperator());
316	27435	Assert(it != visited.end());
317	27435	Assert(!it->second.isNull());
318	27435	childChanged = childChanged \|\| cur.getOperator() != it->second;
319	27435	children.push_back(it->second);
320		}
321	572847	for (const Node& cn : cur)
322		{
323	375303	it = visited.find(cn);
324	375303	Assert(it != visited.end());
325	375303	Assert(!it->second.isNull());
326	375303	childChanged = childChanged \|\| cn != it->second;
327	375303	children.push_back(it->second);
328		}
329	197544	if (childChanged)
330		{
331	56438	ret = nm->mkNode(cur.getKind(), children);
332		}
333	197544	cur.setAttribute(ofa, ret);
334	197544	visited[cur] = ret;
335		}
336	834142	} while (!visit.empty());
337	233860	Assert(visited.find(n) != visited.end());
338	233860	Assert(!visited.find(n)->second.isNull());
339	233860	Trace("sk-manager-debug") << "..return " << visited[n] << std::endl;
340	233860	return visited[n];
341		}
342
343	57968	Node SkolemManager::mkSkolemInternal(Node w,
344		const std::string& prefix,
345		const std::string& comment,
346		int flags)
347		{
348		// note that witness, original forms are independent, but share skolems
349	57968	NodeManager* nm = NodeManager::currentNM();
350		// w is not necessarily a witness term
351		SkolemFormAttribute sfa;
352	115936	Node k;
353		// could already have a skolem if we used w already
354	57968	if (w.hasAttribute(sfa))
355		{
356	12186	return w.getAttribute(sfa);
357		}
358		// make the new skolem
359	45782	if (flags & NodeManager::SKOLEM_BOOL_TERM_VAR)
360		{
361	841	Assert (w.getType().isBoolean());
362	841	k = nm->mkBooleanTermVariable();
363		}
364		else
365		{
366	44941	k = nm->mkSkolem(prefix, w.getType(), comment, flags);
367		}
368		// set skolem form attribute for w
369	45782	w.setAttribute(sfa, k);
370	91564	Trace("sk-manager") << "SkolemManager::mkSkolem: " << k << " : " << w
371	45782	<< std::endl;
372	45782	return k;
373		}
374
375	29337	} // namespace cvc5