From 6f290d8f9e9d7faac295cb51fc96884a18f4ded4 Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Thu, 21 May 2009 04:36:41 +0000
Subject: Initial KLEE checkin.  - Lots more tweaks, documentation, and web
 page content is needed,    but this should compile & work on OS X & Linux.

git-svn-id: https://llvm.org/svn/llvm-project/klee/trunk@72205 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Solver/IndependentSolver.cpp | 314 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 314 insertions(+)
 create mode 100644 lib/Solver/IndependentSolver.cpp

(limited to 'lib/Solver/IndependentSolver.cpp')

diff --git a/lib/Solver/IndependentSolver.cpp b/lib/Solver/IndependentSolver.cpp
new file mode 100644
index 00000000..c966aff6
--- /dev/null
+++ b/lib/Solver/IndependentSolver.cpp
@@ -0,0 +1,314 @@
+//===-- IndependentSolver.cpp ---------------------------------------------===//
+//
+//                     The KLEE Symbolic Virtual Machine
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "klee/Solver.h"
+
+#include "klee/Expr.h"
+#include "klee/Constraints.h"
+#include "klee/SolverImpl.h"
+
+#include "klee/util/ExprUtil.h"
+
+#include "llvm/Support/Streams.h"
+
+#include <map>
+#include <vector>
+
+using namespace klee;
+using namespace llvm;
+
+template<class T>
+class DenseSet {
+  typedef std::set<T> set_ty;
+  set_ty s;
+
+public:
+  DenseSet() {}
+
+  void add(T x) {
+    s.insert(x);
+  }
+  void add(T start, T end) {
+    for (; start<end; start++)
+      s.insert(start);
+  }
+
+  // returns true iff set is changed by addition
+  bool add(const DenseSet &b) {
+    bool modified = false;
+    for (typename set_ty::const_iterator it = b.s.begin(), ie = b.s.end(); 
+         it != ie; ++it) {
+      if (modified || !s.count(*it)) {
+        modified = true;
+        s.insert(*it);
+      }
+    }
+    return modified;
+  }
+
+  bool intersects(const DenseSet &b) {
+    for (typename set_ty::iterator it = s.begin(), ie = s.end(); 
+         it != ie; ++it)
+      if (b.s.count(*it))
+        return true;
+    return false;
+  }
+
+  void print(std::ostream &os) const {
+    bool first = true;
+    os << "{";
+    for (typename set_ty::iterator it = s.begin(), ie = s.end(); 
+         it != ie; ++it) {
+      if (first) {
+        first = false;
+      } else {
+        os << ",";
+      }
+      os << *it;
+    }
+    os << "}";
+  }
+};
+
+template<class T>
+inline std::ostream &operator<<(std::ostream &os, const DenseSet<T> &dis) {
+  dis.print(os);
+  return os;
+}
+
+class IndependentElementSet {
+  typedef std::map<const Array*, DenseSet<unsigned> > elements_ty;
+  elements_ty elements;
+  std::set<const Array*> wholeObjects;
+
+public:
+  IndependentElementSet() {}
+  IndependentElementSet(ref<Expr> e) {
+    std::vector< ref<ReadExpr> > reads;
+    findReads(e, /* visitUpdates= */ true, reads);
+    for (unsigned i = 0; i != reads.size(); ++i) {
+      ReadExpr *re = reads[i].get();
+      if (re->updates.isRooted) {
+        const Array *array = re->updates.root;
+        if (!wholeObjects.count(array)) {
+          if (re->index.isConstant()) {
+            DenseSet<unsigned> &dis = elements[array];
+            dis.add((unsigned) re->index.getConstantValue());
+          } else {
+            elements_ty::iterator it2 = elements.find(array);
+            if (it2!=elements.end())
+              elements.erase(it2);
+            wholeObjects.insert(array);
+          }
+        }
+      }
+    }
+  }
+  IndependentElementSet(const IndependentElementSet &ies) : 
+    elements(ies.elements),
+    wholeObjects(ies.wholeObjects) {}    
+
+  IndependentElementSet &operator=(const IndependentElementSet &ies) {
+    elements = ies.elements;
+    wholeObjects = ies.wholeObjects;
+    return *this;
+  }
+
+  void print(std::ostream &os) const {
+    os << "{";
+    bool first = true;
+    for (std::set<const Array*>::iterator it = wholeObjects.begin(), 
+           ie = wholeObjects.end(); it != ie; ++it) {
+      const Array *array = *it;
+
+      if (first) {
+        first = false;
+      } else {
+        os << ", ";
+      }
+
+      os << "MO" << array->id;
+    }
+    for (elements_ty::const_iterator it = elements.begin(), ie = elements.end();
+         it != ie; ++it) {
+      const Array *array = it->first;
+      const DenseSet<unsigned> &dis = it->second;
+
+      if (first) {
+        first = false;
+      } else {
+        os << ", ";
+      }
+
+      os << "MO" << array->id << " : " << dis;
+    }
+    os << "}";
+  }
+
+  // more efficient when this is the smaller set
+  bool intersects(const IndependentElementSet &b) {
+    for (std::set<const Array*>::iterator it = wholeObjects.begin(), 
+           ie = wholeObjects.end(); it != ie; ++it) {
+      const Array *array = *it;
+      if (b.wholeObjects.count(array) || 
+          b.elements.find(array) != b.elements.end())
+        return true;
+    }
+    for (elements_ty::iterator it = elements.begin(), ie = elements.end();
+         it != ie; ++it) {
+      const Array *array = it->first;
+      if (b.wholeObjects.count(array))
+        return true;
+      elements_ty::const_iterator it2 = b.elements.find(array);
+      if (it2 != b.elements.end()) {
+        if (it->second.intersects(it2->second))
+          return true;
+      }
+    }
+    return false;
+  }
+
+  // returns true iff set is changed by addition
+  bool add(const IndependentElementSet &b) {
+    bool modified = false;
+    for (std::set<const Array*>::const_iterator it = b.wholeObjects.begin(), 
+           ie = b.wholeObjects.end(); it != ie; ++it) {
+      const Array *array = *it;
+      elements_ty::iterator it2 = elements.find(array);
+      if (it2!=elements.end()) {
+        modified = true;
+        elements.erase(it2);
+        wholeObjects.insert(array);
+      } else {
+        if (!wholeObjects.count(array)) {
+          modified = true;
+          wholeObjects.insert(array);
+        }
+      }
+    }
+    for (elements_ty::const_iterator it = b.elements.begin(), 
+           ie = b.elements.end(); it != ie; ++it) {
+      const Array *array = it->first;
+      if (!wholeObjects.count(array)) {
+        elements_ty::iterator it2 = elements.find(array);
+        if (it2==elements.end()) {
+          modified = true;
+          elements.insert(*it);
+        } else {
+          if (it2->second.add(it->second))
+            modified = true;
+        }
+      }
+    }
+    return modified;
+  }
+};
+
+inline std::ostream &operator<<(std::ostream &os, const IndependentElementSet &ies) {
+  ies.print(os);
+  return os;
+}
+
+static 
+IndependentElementSet getIndependentConstraints(const Query& query,
+                                                std::vector< ref<Expr> > &result) {
+  IndependentElementSet eltsClosure(query.expr);
+  std::vector< std::pair<ref<Expr>, IndependentElementSet> > worklist;
+
+  for (ConstraintManager::const_iterator it = query.constraints.begin(), 
+         ie = query.constraints.end(); it != ie; ++it)
+    worklist.push_back(std::make_pair(*it, IndependentElementSet(*it)));
+
+  // XXX This should be more efficient (in terms of low level copy stuff).
+  bool done = false;
+  do {
+    done = true;
+    std::vector< std::pair<ref<Expr>, IndependentElementSet> > newWorklist;
+    for (std::vector< std::pair<ref<Expr>, IndependentElementSet> >::iterator
+           it = worklist.begin(), ie = worklist.end(); it != ie; ++it) {
+      if (it->second.intersects(eltsClosure)) {
+        if (eltsClosure.add(it->second))
+          done = false;
+        result.push_back(it->first);
+      } else {
+        newWorklist.push_back(*it);
+      }
+    }
+    worklist.swap(newWorklist);
+  } while (!done);
+
+  if (0) {
+    std::set< ref<Expr> > reqset(result.begin(), result.end());
+    llvm::cerr << "--\n";
+    llvm::cerr << "Q: " << query.expr << "\n";
+    llvm::cerr << "\telts: " << IndependentElementSet(query.expr) << "\n";
+    int i = 0;
+  for (ConstraintManager::const_iterator it = query.constraints.begin(), 
+         ie = query.constraints.end(); it != ie; ++it) {
+      llvm::cerr << "C" << i++ << ": " << *it;
+      llvm::cerr << " " << (reqset.count(*it) ? "(required)" : "(independent)") << "\n";
+      llvm::cerr << "\telts: " << IndependentElementSet(*it) << "\n";
+    }
+    llvm::cerr << "elts closure: " << eltsClosure << "\n";
+  }
+
+  return eltsClosure;
+}
+
+class IndependentSolver : public SolverImpl {
+private:
+  Solver *solver;
+
+public:
+  IndependentSolver(Solver *_solver) 
+    : solver(_solver) {}
+  ~IndependentSolver() { delete solver; }
+
+  bool computeTruth(const Query&, bool &isValid);
+  bool computeValidity(const Query&, Solver::Validity &result);
+  bool computeValue(const Query&, ref<Expr> &result);
+  bool computeInitialValues(const Query& query,
+                            const std::vector<const Array*> &objects,
+                            std::vector< std::vector<unsigned char> > &values,
+                            bool &hasSolution) {
+    return solver->impl->computeInitialValues(query, objects, values,
+                                              hasSolution);
+  }
+};
+  
+bool IndependentSolver::computeValidity(const Query& query,
+                                        Solver::Validity &result) {
+  std::vector< ref<Expr> > required;
+  IndependentElementSet eltsClosure =
+    getIndependentConstraints(query, required);
+  ConstraintManager tmp(required);
+  return solver->impl->computeValidity(Query(tmp, query.expr), 
+                                       result);
+}
+
+bool IndependentSolver::computeTruth(const Query& query, bool &isValid) {
+  std::vector< ref<Expr> > required;
+  IndependentElementSet eltsClosure = 
+    getIndependentConstraints(query, required);
+  ConstraintManager tmp(required);
+  return solver->impl->computeTruth(Query(tmp, query.expr), 
+                                    isValid);
+}
+
+bool IndependentSolver::computeValue(const Query& query, ref<Expr> &result) {
+  std::vector< ref<Expr> > required;
+  IndependentElementSet eltsClosure = 
+    getIndependentConstraints(query, required);
+  ConstraintManager tmp(required);
+  return solver->impl->computeValue(Query(tmp, query.expr), result);
+}
+
+Solver *klee::createIndependentSolver(Solver *s) {
+  return new Solver(new IndependentSolver(s));
+}
-- 
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