Approximation of tree incrementality for Z3 solver

include/klee/ADT/Incremental.h

@@ -0,0 +1,358 @@
+//===---- Incremental.h -----------------------------------------*- C++ -*-===//
+//
+//                     The KLEE Symbolic Virtual Machine
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef KLEE_INCREMENTAL_H
+#define KLEE_INCREMENTAL_H
+
+#include <cassert>
+#include <memory>
+#include <numeric>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+#include "klee/Expr/ExprUtil.h"
+
+namespace klee {
+
+template <typename _Tp, typename _Alloc>
+void extend(std::vector<_Tp, _Alloc> &ths,
+            const std::vector<_Tp, _Alloc> &other) {
+  ths.reserve(ths.size() + other.size());
+  ths.insert(ths.end(), other.begin(), other.end());
+}
+
+template <typename _Tp, typename _Alloc = std::allocator<_Tp>>
+class inc_vector {
+public:
+  using vec = std::vector<_Tp, _Alloc>;
+  using frame_size_it = std::vector<size_t>::const_iterator;
+  using frame_it = typename vec::const_iterator;
+
+  /// It is public, so that all vector operations are supported
+  /// Everything pushed to v is pushed to the last frame
+  vec v;
+
+  std::vector<size_t> frame_sizes;
+
+private:
+  // v.size() == sum(frame_sizes) + size of the fresh frame
+
+  size_t freshFrameSize() const {
+    return v.size() -
+           std::accumulate(frame_sizes.begin(), frame_sizes.end(), 0);
+  }
+
+  void take(size_t n, size_t &frames_count, size_t &frame_index) const {
+    size_t i = 0;
+    size_t c = n;
+    for (; i < frame_sizes.size(); i++) {
+      if (frame_sizes[i] > c)
+        break;
+      c -= frame_sizes[i];
+    }
+    frames_count = c;
+    frame_index = i;
+  }
+
+public:
+  inc_vector() {}
+  inc_vector(const std::vector<_Tp> &constraints) : v(constraints) {}
+
+  void clear() {
+    v.clear();
+    frame_sizes.clear();
+  }
+
+  frame_size_it begin() const { return frame_sizes.cbegin(); }
+  frame_size_it end() const { return frame_sizes.cend(); }
+  size_t framesSize() const { return frame_sizes.size() + 1; }
+
+  frame_it begin(int frame_index) const {
+    assert(-(long long)framesSize() <= (long long)frame_index &&
+           (long long)frame_index <= (long long)framesSize());
+    if (frame_index < 0)
+      frame_index += framesSize();
+    if ((long long)frame_index == (long long)framesSize())
+      return v.end();
+    auto fend = frame_sizes.begin() + frame_index;
+    auto shift = std::accumulate(frame_sizes.begin(), fend, 0);
+    return v.begin() + shift;
+  }
+  frame_it end(int frame_index) const { return begin(frame_index + 1); }
+  size_t size(size_t frame_index) const {
+    assert(frame_index < framesSize());
+    if (frame_index == framesSize() - 1) // last frame
+      return freshFrameSize();
+    return frame_sizes[frame_index];
+  }
+
+  void pop(size_t popFrames) {
+    assert(freshFrameSize() == 0);
+    if (popFrames == 0)
+      return;
+    size_t toPop =
+        std::accumulate(frame_sizes.end() - popFrames, frame_sizes.end(), 0);
+    v.resize(v.size() - toPop);
+    frame_sizes.resize(frame_sizes.size() - popFrames);
+  }
+
+  void push() {
+    auto freshSize = freshFrameSize();
+    frame_sizes.push_back(freshSize);
+    assert(freshFrameSize() == 0);
+  }
+
+  /// ensures that last frame is empty
+  void extend(const std::vector<_Tp, _Alloc> &other) {
+    assert(freshFrameSize() == 0);
+    // push();
+    klee::extend(v, other);
+    push();
+  }
+
+  /// ensures that last frame is empty
+  void extend(const inc_vector<_Tp, _Alloc> &other) {
+    assert(freshFrameSize() == 0);
+    for (size_t i = 0, e = other.framesSize(); i < e; i++) {
+      v.reserve(v.size() + other.size(i));
+      v.insert(v.end(), other.begin(i), other.end(i));
+      push();
+    }
+  }
+
+  void takeAfter(size_t n, inc_vector<_Tp, _Alloc> &result) const {
+    size_t frames_count, frame_index;
+    take(n, frames_count, frame_index);
+    result = *this;
+    std::vector<_Tp, _Alloc>(result.v.begin() + n, result.v.end())
+        .swap(result.v);
+    std::vector<size_t>(result.frame_sizes.begin() + frame_index,
+                        result.frame_sizes.end())
+        .swap(result.frame_sizes);
+    if (frames_count)
+      result.frame_sizes[0] -= frames_count;
+  }
+
+  void butLast(inc_vector<_Tp, _Alloc> &result) const {
+    assert(!v.empty() && "butLast of empty vector");
+    assert(freshFrameSize() && "butLast of empty fresh frame");
+    result = *this;
+    result.v.pop_back();
+  }
+
+  void takeBefore(size_t n, size_t &toPop, size_t &takeFromOther) const {
+    take(n, takeFromOther, toPop);
+    toPop = frame_sizes.size() - toPop;
+  }
+};
+
+using FrameId = size_t;
+using FrameIds = std::unordered_set<FrameId>;
+
+template <typename _Value, typename _Hash = std::hash<_Value>,
+          typename _Pred = std::equal_to<_Value>,
+          typename _Alloc = std::allocator<_Value>>
+class inc_uset {
+private:
+  class MinFrameIds {
+    FrameIds ids;
+    FrameId min = std::numeric_limits<FrameId>::max();
+
+  public:
+    bool empty() const { return ids.empty(); }
+
+    bool hasMin(FrameId other) const { return min == other && !ids.empty(); }
+
+    void insert(FrameId i) {
+      ids.insert(i);
+      if (i < min)
+        min = i;
+    }
+
+    MinFrameIds bound(FrameId upperBound) {
+      MinFrameIds result;
+      std::copy_if(ids.begin(), ids.end(),
+                   std::inserter(result.ids, result.ids.begin()),
+                   [upperBound](FrameId i) { return i <= upperBound; });
+      auto min_it = std::min_element(result.ids.begin(), result.ids.end());
+      if (min_it == result.ids.end())
+        result.min = std::numeric_limits<FrameId>::max();
+      else
+        result.min = *min_it;
+      return result;
+    }
+  };
+
+  using idMap = std::unordered_map<_Value, MinFrameIds, _Hash, _Pred, _Alloc>;
+  using citerator = typename idMap::const_iterator;
+  idMap ids;
+  FrameId current_frame = 0;
+
+public:
+  size_t framesSize() const { return current_frame + 1; }
+
+  void clear() {
+    ids.clear();
+    current_frame = 0;
+  }
+
+  class frame_it
+      : public std::iterator<std::forward_iterator_tag, ref<Expr>, int> {
+    citerator set_it;
+    const citerator set_ite;
+    const FrameId frame_index = 0;
+
+    void gotoNext() {
+      while (set_it != set_ite && !set_it->second.hasMin(frame_index))
+        set_it++;
+    }
+
+  public:
+    using value_type = _Value;
+
+    explicit frame_it(const idMap &ids)
+        : set_it(ids.end()), set_ite(ids.end()) {}
+    explicit frame_it(const idMap &ids, FrameId frame_index)
+        : set_it(ids.begin()), set_ite(ids.end()), frame_index(frame_index) {
+      gotoNext();
+    }
+
+    bool operator!=(const frame_it &other) const {
+      return set_it != other.set_it;
+    }
+
+    const _Value &operator*() const { return set_it->first; }
+
+    frame_it &operator++() {
+      if (set_it != set_ite) {
+        set_it++;
+        gotoNext();
+      }
+      return *this;
+    }
+  };
+
+  class all_it
+      : public std::iterator<std::forward_iterator_tag, ref<Expr>, int> {
+    citerator set_it;
+
+  public:
+    using value_type = _Value;
+
+    explicit all_it(citerator set_it) : set_it(set_it) {}
+
+    bool operator!=(const all_it &other) const {
+      return set_it != other.set_it;
+    }
+
+    const _Value &operator*() const { return set_it->first; }
+
+    all_it &operator++() {
+      set_it++;
+      return *this;
+    }
+  };
+
+  all_it begin() const { return all_it(ids.begin()); }
+  all_it end() const { return all_it(ids.end()); }
+
+  frame_it begin(int frame_index) const {
+    assert(-(long long)framesSize() <= (long long)frame_index &&
+           (long long)frame_index <= (long long)framesSize());
+    if (frame_index < 0)
+      frame_index += framesSize();
+    return frame_it(ids, frame_index);
+  }
+  frame_it end(int frame_index) const { return frame_it(ids); }
+
+  void insert(const _Value &v) { ids[v].insert(current_frame); }
+
+  template <class _InputIterator>
+  void insert(_InputIterator __first, _InputIterator __last) {
+    for (; __first != __last; __first++)
+      ids[*__first].insert(current_frame);
+  }
+
+  void pop(size_t popFrames) {
+    current_frame -= popFrames;
+    idMap newIdMap;
+    for (auto &keyAndIds : ids) {
+      MinFrameIds newIds = keyAndIds.second.bound(current_frame);
+      if (!newIds.empty())
+        newIdMap.insert(std::make_pair(keyAndIds.first, newIds));
+    }
+    ids = newIdMap;
+  }
+
+  void push() { current_frame++; }
+};
+
+template <typename _Key, typename _Tp, typename _Hash = std::hash<_Key>,
+          typename _Pred = std::equal_to<_Key>,
+          typename _Alloc = std::allocator<std::pair<const _Key, _Tp>>>
+class inc_umap {
+private:
+  std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc> map;
+  using idMap = std::unordered_map<_Key, FrameIds, _Hash, _Pred, _Alloc>;
+  idMap ids;
+  FrameId current_frame = 0;
+
+public:
+  void clear() {
+    map.clear();
+    ids.clear();
+    current_frame = 0;
+  }
+
+  void insert(const std::pair<_Key, _Tp> &pair) {
+    map.insert(pair);
+    ids[pair.first].insert(current_frame);
+  }
+
+  _Tp &operator[](const _Key &key) {
+    ids[key].insert(current_frame);
+    return map[key];
+  }
+
+  size_t count(const _Key &key) const { return map.count(key); }
+
+  const _Tp &at(_Key &key) const { return map.at(key); }
+
+  void pop(size_t popFrames) {
+    current_frame -= popFrames;
+    idMap newIdMap;
+    for (auto &keyAndIds : ids) {
+      FrameIds newIds;
+      for (auto id : keyAndIds.second)
+        if (id <= current_frame)
+          newIds.insert(id);
+      if (newIds.empty())
+        map.erase(keyAndIds.first);
+      else
+        newIdMap.insert(std::make_pair(keyAndIds.first, newIds));
+    }
+    ids = newIdMap;
+  }
+
+  void push() { current_frame++; }
+
+  void dump() const {
+    for (auto kv : map) {
+      kv.first.dump();
+      llvm::errs() << "----->\n";
+      kv.second.dump();
+      llvm::errs() << "\n;;;;;;;;;\n";
+    }
+  }
+};
+
+} // namespace klee
+
+#endif /* KLEE_INCREMENTAL_H */

include/klee/Expr/Constraints.h

@@ -37,9 +37,11 @@ class ConstraintSet {
 public:
   ConstraintSet(constraints_ty cs, symcretes_ty symcretes,
                 Assignment concretization);
-  ConstraintSet(ref<const IndependentConstraintSet> ics);
-  ConstraintSet(const std::vector<ref<const IndependentConstraintSet>> &ics);
-  ConstraintSet();
+  explicit ConstraintSet(ref<const IndependentConstraintSet> ics);
+  explicit ConstraintSet(
+      const std::vector<ref<const IndependentConstraintSet>> &ics);
+  explicit ConstraintSet(constraints_ty cs);
+  explicit ConstraintSet();
 
   void addConstraint(ref<Expr> e, const Assignment &delta);
   void addSymcrete(ref<Symcrete> s, const Assignment &concretization);

include/klee/Solver/IncompleteSolver.h

@@ -80,6 +80,7 @@ class StagedSolverImpl : public SolverImpl {
   SolverRunStatus getOperationStatusCode();
   char *getConstraintLog(const Query &);
   void setCoreSolverTimeout(time::Span timeout);
+  void notifyStateTermination(std::uint32_t id);
 };
 
 } // namespace klee