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