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+//== RangeConstraintManager.cpp - Manage range constraints.------*- C++ -*--==//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines RangeConstraintManager, a class that tracks simple
+// equality and inequality constraints on symbolic values of GRState.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SimpleConstraintManager.h"
+#include "clang/Analysis/PathSensitive/GRState.h"
+#include "clang/Analysis/PathSensitive/GRStateTrait.h"
+#include "clang/Analysis/PathSensitive/GRTransferFuncs.h"
+#include "clang/Frontend/ManagerRegistry.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/ImmutableSet.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+
+namespace { class VISIBILITY_HIDDEN ConstraintRange {}; }
+static int ConstraintRangeIndex = 0;
+
+/// A Range represents the closed range [from, to]. The caller must
+/// guarantee that from <= to. Note that Range is immutable, so as not
+/// to subvert RangeSet's immutability.
+namespace {
+class VISIBILITY_HIDDEN Range : public std::pair<const llvm::APSInt*,
+ const llvm::APSInt*> {
+public:
+ Range(const llvm::APSInt &from, const llvm::APSInt &to)
+ : std::pair<const llvm::APSInt*, const llvm::APSInt*>(&from, &to) {
+ assert(from <= to);
+ }
+ bool Includes(const llvm::APSInt &v) const {
+ return *first <= v && v <= *second;
+ }
+ const llvm::APSInt &From() const {
+ return *first;
+ }
+ const llvm::APSInt &To() const {
+ return *second;
+ }
+ const llvm::APSInt *getConcreteValue() const {
+ return &From() == &To() ? &From() : NULL;
+ }
+
+ void Profile(llvm::FoldingSetNodeID &ID) const {
+ ID.AddPointer(&From());
+ ID.AddPointer(&To());
+ }
+};
+
+
+class VISIBILITY_HIDDEN RangeTrait : public llvm::ImutContainerInfo<Range> {
+public:
+ // When comparing if one Range is less than another, we should compare
+ // the actual APSInt values instead of their pointers. This keeps the order
+ // consistent (instead of comparing by pointer values) and can potentially
+ // be used to speed up some of the operations in RangeSet.
+ static inline bool isLess(key_type_ref lhs, key_type_ref rhs) {
+ return *lhs.first < *rhs.first || (!(*rhs.first < *lhs.first) &&
+ *lhs.second < *rhs.second);
+ }
+};
+
+/// RangeSet contains a set of ranges. If the set is empty, then
+/// there the value of a symbol is overly constrained and there are no
+/// possible values for that symbol.
+class VISIBILITY_HIDDEN RangeSet {
+ typedef llvm::ImmutableSet<Range, RangeTrait> PrimRangeSet;
+ PrimRangeSet ranges; // no need to make const, since it is an
+ // ImmutableSet - this allows default operator=
+ // to work.
+public:
+ typedef PrimRangeSet::Factory Factory;
+ typedef PrimRangeSet::iterator iterator;
+
+ RangeSet(PrimRangeSet RS) : ranges(RS) {}
+ RangeSet(Factory& F) : ranges(F.GetEmptySet()) {}
+
+ iterator begin() const { return ranges.begin(); }
+ iterator end() const { return ranges.end(); }
+
+ bool isEmpty() const { return ranges.isEmpty(); }
+
+ /// Construct a new RangeSet representing '{ [from, to] }'.
+ RangeSet(Factory &F, const llvm::APSInt &from, const llvm::APSInt &to)
+ : ranges(F.Add(F.GetEmptySet(), Range(from, to))) {}
+
+ /// Profile - Generates a hash profile of this RangeSet for use
+ /// by FoldingSet.
+ void Profile(llvm::FoldingSetNodeID &ID) const { ranges.Profile(ID); }
+
+ /// getConcreteValue - If a symbol is contrained to equal a specific integer
+ /// constant then this method returns that value. Otherwise, it returns
+ /// NULL.
+ const llvm::APSInt* getConcreteValue() const {
+ return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : 0;
+ }
+
+ /// AddEQ - Create a new RangeSet with the additional constraint that the
+ /// value be equal to V.
+ RangeSet AddEQ(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+ // Search for a range that includes 'V'. If so, return a new RangeSet
+ // representing { [V, V] }.
+ for (PrimRangeSet::iterator i = begin(), e = end(); i!=e; ++i)
+ if (i->Includes(V))
+ return RangeSet(F, V, V);
+
+ return RangeSet(F);
+ }
+
+ /// AddNE - Create a new RangeSet with the additional constraint that the
+ /// value be not be equal to V.
+ RangeSet AddNE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+ PrimRangeSet newRanges = ranges;
+
+ // FIXME: We can perhaps enhance ImmutableSet to do this search for us
+ // in log(N) time using the sorted property of the internal AVL tree.
+ for (iterator i = begin(), e = end(); i != e; ++i) {
+ if (i->Includes(V)) {
+ // Remove the old range.
+ newRanges = F.Remove(newRanges, *i);
+ // Split the old range into possibly one or two ranges.
+ if (V != i->From())
+ newRanges = F.Add(newRanges, Range(i->From(), BV.Sub1(V)));
+ if (V != i->To())
+ newRanges = F.Add(newRanges, Range(BV.Add1(V), i->To()));
+ // All of the ranges are non-overlapping, so we can stop.
+ break;
+ }
+ }
+
+ return newRanges;
+ }
+
+ /// AddNE - Create a new RangeSet with the additional constraint that the
+ /// value be less than V.
+ RangeSet AddLT(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+ PrimRangeSet newRanges = F.GetEmptySet();
+
+ for (iterator i = begin(), e = end() ; i != e ; ++i) {
+ if (i->Includes(V) && i->From() < V)
+ newRanges = F.Add(newRanges, Range(i->From(), BV.Sub1(V)));
+ else if (i->To() < V)
+ newRanges = F.Add(newRanges, *i);
+ }
+
+ return newRanges;
+ }
+
+ RangeSet AddLE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+ PrimRangeSet newRanges = F.GetEmptySet();
+
+ for (iterator i = begin(), e = end(); i != e; ++i) {
+ // Strictly we should test for includes *V + 1, but no harm is
+ // done by this formulation
+ if (i->Includes(V))
+ newRanges = F.Add(newRanges, Range(i->From(), V));
+ else if (i->To() <= V)
+ newRanges = F.Add(newRanges, *i);
+ }
+
+ return newRanges;
+ }
+
+ RangeSet AddGT(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+ PrimRangeSet newRanges = F.GetEmptySet();
+
+ for (PrimRangeSet::iterator i = begin(), e = end(); i != e; ++i) {
+ if (i->Includes(V) && i->To() > V)
+ newRanges = F.Add(newRanges, Range(BV.Add1(V), i->To()));
+ else if (i->From() > V)
+ newRanges = F.Add(newRanges, *i);
+ }
+
+ return newRanges;
+ }
+
+ RangeSet AddGE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+ PrimRangeSet newRanges = F.GetEmptySet();
+
+ for (PrimRangeSet::iterator i = begin(), e = end(); i != e; ++i) {
+ // Strictly we should test for includes *V - 1, but no harm is
+ // done by this formulation
+ if (i->Includes(V))
+ newRanges = F.Add(newRanges, Range(V, i->To()));
+ else if (i->From() >= V)
+ newRanges = F.Add(newRanges, *i);
+ }
+
+ return newRanges;
+ }
+
+ void Print(std::ostream &os) const {
+ bool isFirst = true;
+ os << "{ ";
+ for (iterator i = begin(), e = end(); i != e; ++i) {
+ if (isFirst)
+ isFirst = false;
+ else
+ os << ", ";
+
+ os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
+ << ']';
+ }
+ os << " }";
+ }
+
+ bool operator==(const RangeSet &other) const {
+ return ranges == other.ranges;
+ }
+};
+} // end anonymous namespace
+
+typedef llvm::ImmutableMap<SymbolRef,RangeSet> ConstraintRangeTy;
+
+namespace clang {
+template<>
+struct GRStateTrait<ConstraintRange>
+ : public GRStatePartialTrait<ConstraintRangeTy> {
+ static inline void* GDMIndex() { return &ConstraintRangeIndex; }
+};
+}
+
+namespace {
+class VISIBILITY_HIDDEN RangeConstraintManager : public SimpleConstraintManager{
+ RangeSet GetRange(GRStateRef state, SymbolRef sym);
+public:
+ RangeConstraintManager(GRStateManager& statemgr)
+ : SimpleConstraintManager(statemgr) {}
+
+ const GRState* AssumeSymNE(const GRState* St, SymbolRef sym,
+ const llvm::APSInt& V, bool& isFeasible);
+
+ const GRState* AssumeSymEQ(const GRState* St, SymbolRef sym,
+ const llvm::APSInt& V, bool& isFeasible);
+
+ const GRState* AssumeSymLT(const GRState* St, SymbolRef sym,
+ const llvm::APSInt& V, bool& isFeasible);
+
+ const GRState* AssumeSymGT(const GRState* St, SymbolRef sym,
+ const llvm::APSInt& V, bool& isFeasible);
+
+ const GRState* AssumeSymGE(const GRState* St, SymbolRef sym,
+ const llvm::APSInt& V, bool& isFeasible);
+
+ const GRState* AssumeSymLE(const GRState* St, SymbolRef sym,
+ const llvm::APSInt& V, bool& isFeasible);
+
+ const llvm::APSInt* getSymVal(const GRState* St, SymbolRef sym) const;
+
+ // FIXME: Refactor into SimpleConstraintManager?
+ bool isEqual(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const {
+ const llvm::APSInt *i = getSymVal(St, sym);
+ return i ? *i == V : false;
+ }
+
+ const GRState* RemoveDeadBindings(const GRState* St, SymbolReaper& SymReaper);
+
+ void print(const GRState* St, std::ostream& Out,
+ const char* nl, const char *sep);
+
+private:
+ RangeSet::Factory F;
+};
+
+} // end anonymous namespace
+
+ConstraintManager* clang::CreateRangeConstraintManager(GRStateManager& StateMgr)
+{
+ return new RangeConstraintManager(StateMgr);
+}
+
+const llvm::APSInt* RangeConstraintManager::getSymVal(const GRState* St,
+ SymbolRef sym) const {
+ const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(sym);
+ return T ? T->getConcreteValue() : NULL;
+}
+
+/// Scan all symbols referenced by the constraints. If the symbol is not alive
+/// as marked in LSymbols, mark it as dead in DSymbols.
+const GRState*
+RangeConstraintManager::RemoveDeadBindings(const GRState* St,
+ SymbolReaper& SymReaper) {
+ GRStateRef state(St, StateMgr);
+
+ ConstraintRangeTy CR = state.get<ConstraintRange>();
+ ConstraintRangeTy::Factory& CRFactory = state.get_context<ConstraintRange>();
+
+ for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
+ SymbolRef sym = I.getKey();
+ if (SymReaper.maybeDead(sym))
+ CR = CRFactory.Remove(CR, sym);
+ }
+
+ return state.set<ConstraintRange>(CR);
+}
+
+//===------------------------------------------------------------------------===
+// AssumeSymX methods: public interface for RangeConstraintManager.
+//===------------------------------------------------------------------------===/
+
+RangeSet
+RangeConstraintManager::GetRange(GRStateRef state, SymbolRef sym) {
+ if (ConstraintRangeTy::data_type* V = state.get<ConstraintRange>(sym))
+ return *V;
+
+ // Lazily generate a new RangeSet representing all possible values for the
+ // given symbol type.
+ QualType T = state.getSymbolManager().getType(sym);
+ BasicValueFactory& BV = state.getBasicVals();
+ return RangeSet(F, BV.getMinValue(T), BV.getMaxValue(T));
+}
+
+//===------------------------------------------------------------------------===
+// AssumeSymX methods: public interface for RangeConstraintManager.
+//===------------------------------------------------------------------------===/
+
+#define AssumeX(OP)\
+const GRState*\
+RangeConstraintManager::AssumeSym ## OP(const GRState* St, SymbolRef sym,\
+ const llvm::APSInt& V, bool& isFeasible){\
+ GRStateRef state(St, StateMgr);\
+ const RangeSet& R = GetRange(state, sym).Add##OP(state.getBasicVals(), F, V);\
+ isFeasible = !R.isEmpty();\
+ return isFeasible ? state.set<ConstraintRange>(sym, R).getState() : 0;\
+}
+
+AssumeX(EQ)
+AssumeX(NE)
+AssumeX(LT)
+AssumeX(GT)
+AssumeX(LE)
+AssumeX(GE)
+
+//===------------------------------------------------------------------------===
+// Pretty-printing.
+//===------------------------------------------------------------------------===/
+
+void RangeConstraintManager::print(const GRState* St, std::ostream& Out,
+ const char* nl, const char *sep) {
+
+ ConstraintRangeTy Ranges = St->get<ConstraintRange>();
+
+ if (Ranges.isEmpty())
+ return;
+
+ Out << nl << sep << "ranges of symbol values:";
+
+ for (ConstraintRangeTy::iterator I=Ranges.begin(), E=Ranges.end(); I!=E; ++I){
+ Out << nl << ' ' << I.getKey() << " : ";
+ I.getData().Print(Out);
+ }
+}
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