1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds, Andres Noetzli, 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 expand definitions for an SMT engine.
*/
#include "smt/expand_definitions.h"
#include <stack>
#include <utility>
#include "expr/node_manager_attributes.h"
#include "preprocessing/assertion_pipeline.h"
#include "proof/conv_proof_generator.h"
#include "smt/env.h"
#include "smt/smt_engine.h"
#include "smt/smt_engine_stats.h"
#include "theory/rewriter.h"
#include "theory/theory.h"
#include "util/resource_manager.h"
using namespace cvc5::preprocessing;
using namespace cvc5::theory;
using namespace cvc5::kind;
namespace cvc5 {
namespace smt {
ExpandDefs::ExpandDefs(Env& env, SmtEngineStatistics& stats)
: d_env(env), d_smtStats(stats), d_tpg(nullptr)
{
}
ExpandDefs::~ExpandDefs() {}
Node ExpandDefs::expandDefinitions(TNode n,
std::unordered_map<Node, Node>& cache)
{
TrustNode trn = expandDefinitions(n, cache, nullptr);
return trn.isNull() ? Node(n) : trn.getNode();
}
TrustNode ExpandDefs::expandDefinitions(TNode n,
std::unordered_map<Node, Node>& cache,
TConvProofGenerator* tpg)
{
const TNode orig = n;
std::stack<std::tuple<Node, Node, bool>> worklist;
std::stack<Node> result;
worklist.push(std::make_tuple(Node(n), Node(n), false));
// The worklist is made of triples, each is input / original node then the
// output / rewritten node and finally a flag tracking whether the children
// have been explored (i.e. if this is a downward or upward pass).
ResourceManager* rm = d_env.getResourceManager();
Rewriter* rr = d_env.getRewriter();
do
{
rm->spendResource(Resource::PreprocessStep);
// n is the input / original
// node is the output / result
Node node;
bool childrenPushed;
std::tie(n, node, childrenPushed) = worklist.top();
worklist.pop();
// Working downwards
if (!childrenPushed)
{
// we can short circuit (variable) leaves
if (n.isVar())
{
// don't bother putting in the cache
result.push(n);
continue;
}
// maybe it's in the cache
std::unordered_map<Node, Node>::iterator cacheHit = cache.find(n);
if (cacheHit != cache.end())
{
TNode ret = (*cacheHit).second;
result.push(ret.isNull() ? n : ret);
continue;
}
theory::TheoryId tid = theory::Theory::theoryOf(node);
theory::TheoryRewriter* tr = rr->getTheoryRewriter(tid);
Assert(tr != NULL);
TrustNode trn = tr->expandDefinition(n);
if (!trn.isNull())
{
node = trn.getNode();
if (tpg != nullptr)
{
tpg->addRewriteStep(
n, node, trn.getGenerator(), true, PfRule::THEORY_EXPAND_DEF);
}
}
else
{
node = n;
}
// the partial functions can fall through, in which case we still
// consider their children
worklist.push(std::make_tuple(
Node(n), node, true)); // Original and rewritten result
for (size_t i = 0; i < node.getNumChildren(); ++i)
{
worklist.push(
std::make_tuple(node[i],
node[i],
false)); // Rewrite the children of the result only
}
}
else
{
// Working upwards
// Reconstruct the node from it's (now rewritten) children on the stack
Debug("expand") << "cons : " << node << std::endl;
if (node.getNumChildren() > 0)
{
// cout << "cons : " << node << std::endl;
NodeBuilder nb(node.getKind());
if (node.getMetaKind() == metakind::PARAMETERIZED)
{
Debug("expand") << "op : " << node.getOperator() << std::endl;
// cout << "op : " << node.getOperator() << std::endl;
nb << node.getOperator();
}
for (size_t i = 0, nchild = node.getNumChildren(); i < nchild; ++i)
{
Assert(!result.empty());
Node expanded = result.top();
result.pop();
// cout << "exchld : " << expanded << std::endl;
Debug("expand") << "exchld : " << expanded << std::endl;
nb << expanded;
}
node = nb;
}
// Only cache once all subterms are expanded
cache[n] = n == node ? Node::null() : node;
result.push(node);
}
} while (!worklist.empty());
AlwaysAssert(result.size() == 1);
Node res = result.top();
if (res == orig)
{
return TrustNode::null();
}
return TrustNode::mkTrustRewrite(orig, res, tpg);
}
void ExpandDefs::setProofNodeManager(ProofNodeManager* pnm)
{
if (d_tpg == nullptr)
{
d_tpg.reset(new TConvProofGenerator(pnm,
d_env.getUserContext(),
TConvPolicy::FIXPOINT,
TConvCachePolicy::NEVER,
"ExpandDefs::TConvProofGenerator",
nullptr,
true));
}
}
} // namespace smt
} // namespace cvc5
|
