Chris Lattner has strong opinions about directory
layout. :)
Rename the 'EntoSA' directories to 'StaticAnalyzer'.
Internally we will still use the 'ento' namespace
for the analyzer engine (unless there are further
sabre rattlings...).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122514 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/RangeConstraintManager.cpp b/lib/StaticAnalyzer/RangeConstraintManager.cpp
new file mode 100644
index 0000000..c89fa50
--- /dev/null
+++ b/lib/StaticAnalyzer/RangeConstraintManager.cpp
@@ -0,0 +1,442 @@
+//== 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/StaticAnalyzer/PathSensitive/GRState.h"
+#include "clang/StaticAnalyzer/PathSensitive/GRStateTrait.h"
+#include "clang/StaticAnalyzer/PathSensitive/TransferFuncs.h"
+#include "clang/StaticAnalyzer/ManagerRegistry.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;
+using namespace ento;
+
+namespace { class 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 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 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 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) {}
+
+ 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;
+ }
+
+private:
+ void IntersectInRange(BasicValueFactory &BV, Factory &F,
+ const llvm::APSInt &Lower,
+ const llvm::APSInt &Upper,
+ PrimRangeSet &newRanges,
+ PrimRangeSet::iterator &i,
+ PrimRangeSet::iterator &e) const {
+ // There are six cases for each range R in the set:
+ // 1. R is entirely before the intersection range.
+ // 2. R is entirely after the intersection range.
+ // 3. R contains the entire intersection range.
+ // 4. R starts before the intersection range and ends in the middle.
+ // 5. R starts in the middle of the intersection range and ends after it.
+ // 6. R is entirely contained in the intersection range.
+ // These correspond to each of the conditions below.
+ for (/* i = begin(), e = end() */; i != e; ++i) {
+ if (i->To() < Lower) {
+ continue;
+ }
+ if (i->From() > Upper) {
+ break;
+ }
+
+ if (i->Includes(Lower)) {
+ if (i->Includes(Upper)) {
+ newRanges = F.add(newRanges, Range(BV.getValue(Lower),
+ BV.getValue(Upper)));
+ break;
+ } else
+ newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
+ } else {
+ if (i->Includes(Upper)) {
+ newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
+ break;
+ } else
+ newRanges = F.add(newRanges, *i);
+ }
+ }
+ }
+
+public:
+ // Returns a set containing the values in the receiving set, intersected with
+ // the closed range [Lower, Upper]. Unlike the Range type, this range uses
+ // modular arithmetic, corresponding to the common treatment of C integer
+ // overflow. Thus, if the Lower bound is greater than the Upper bound, the
+ // range is taken to wrap around. This is equivalent to taking the
+ // intersection with the two ranges [Min, Upper] and [Lower, Max],
+ // or, alternatively, /removing/ all integers between Upper and Lower.
+ RangeSet Intersect(BasicValueFactory &BV, Factory &F,
+ const llvm::APSInt &Lower,
+ const llvm::APSInt &Upper) const {
+ PrimRangeSet newRanges = F.getEmptySet();
+
+ PrimRangeSet::iterator i = begin(), e = end();
+ if (Lower <= Upper)
+ IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
+ else {
+ // The order of the next two statements is important!
+ // IntersectInRange() does not reset the iteration state for i and e.
+ // Therefore, the lower range most be handled first.
+ IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
+ IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
+ }
+ return newRanges;
+ }
+
+ void print(llvm::raw_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 {
+namespace ento {
+template<>
+struct GRStateTrait<ConstraintRange>
+ : public GRStatePartialTrait<ConstraintRangeTy> {
+ static inline void* GDMIndex() { return &ConstraintRangeIndex; }
+};
+}
+}
+
+namespace {
+class RangeConstraintManager : public SimpleConstraintManager{
+ RangeSet GetRange(const GRState *state, SymbolRef sym);
+public:
+ RangeConstraintManager(SubEngine &subengine)
+ : SimpleConstraintManager(subengine) {}
+
+ const GRState *assumeSymNE(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment);
+
+ const GRState *assumeSymEQ(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment);
+
+ const GRState *assumeSymLT(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment);
+
+ const GRState *assumeSymGT(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment);
+
+ const GRState *assumeSymGE(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment);
+
+ const GRState *assumeSymLE(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment);
+
+ 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, llvm::raw_ostream& Out,
+ const char* nl, const char *sep);
+
+private:
+ RangeSet::Factory F;
+};
+
+} // end anonymous namespace
+
+ConstraintManager* ento::CreateRangeConstraintManager(GRStateManager&,
+ SubEngine &subeng) {
+ return new RangeConstraintManager(subeng);
+}
+
+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* state,
+ SymbolReaper& SymReaper) {
+
+ 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);
+}
+
+RangeSet
+RangeConstraintManager::GetRange(const GRState *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.
+//===------------------------------------------------------------------------===/
+
+// The syntax for ranges below is mathematical, using [x, y] for closed ranges
+// and (x, y) for open ranges. These ranges are modular, corresponding with
+// a common treatment of C integer overflow. This means that these methods
+// do not have to worry about overflow; RangeSet::Intersect can handle such a
+// "wraparound" range.
+// As an example, the range [UINT_MAX-1, 3) contains five values: UINT_MAX-1,
+// UINT_MAX, 0, 1, and 2.
+
+const GRState*
+RangeConstraintManager::assumeSymNE(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment) {
+ BasicValueFactory &BV = state->getBasicVals();
+
+ llvm::APSInt Lower = Int-Adjustment;
+ llvm::APSInt Upper = Lower;
+ --Lower;
+ ++Upper;
+
+ // [Int-Adjustment+1, Int-Adjustment-1]
+ // Notice that the lower bound is greater than the upper bound.
+ RangeSet New = GetRange(state, sym).Intersect(BV, F, Upper, Lower);
+ return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
+}
+
+const GRState*
+RangeConstraintManager::assumeSymEQ(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment) {
+ // [Int-Adjustment, Int-Adjustment]
+ BasicValueFactory &BV = state->getBasicVals();
+ llvm::APSInt AdjInt = Int-Adjustment;
+ RangeSet New = GetRange(state, sym).Intersect(BV, F, AdjInt, AdjInt);
+ return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
+}
+
+const GRState*
+RangeConstraintManager::assumeSymLT(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment) {
+ BasicValueFactory &BV = state->getBasicVals();
+
+ QualType T = state->getSymbolManager().getType(sym);
+ const llvm::APSInt &Min = BV.getMinValue(T);
+
+ // Special case for Int == Min. This is always false.
+ if (Int == Min)
+ return NULL;
+
+ llvm::APSInt Lower = Min-Adjustment;
+ llvm::APSInt Upper = Int-Adjustment;
+ --Upper;
+
+ RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
+ return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
+}
+
+const GRState*
+RangeConstraintManager::assumeSymGT(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment) {
+ BasicValueFactory &BV = state->getBasicVals();
+
+ QualType T = state->getSymbolManager().getType(sym);
+ const llvm::APSInt &Max = BV.getMaxValue(T);
+
+ // Special case for Int == Max. This is always false.
+ if (Int == Max)
+ return NULL;
+
+ llvm::APSInt Lower = Int-Adjustment;
+ llvm::APSInt Upper = Max-Adjustment;
+ ++Lower;
+
+ RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
+ return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
+}
+
+const GRState*
+RangeConstraintManager::assumeSymGE(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment) {
+ BasicValueFactory &BV = state->getBasicVals();
+
+ QualType T = state->getSymbolManager().getType(sym);
+ const llvm::APSInt &Min = BV.getMinValue(T);
+
+ // Special case for Int == Min. This is always feasible.
+ if (Int == Min)
+ return state;
+
+ const llvm::APSInt &Max = BV.getMaxValue(T);
+
+ llvm::APSInt Lower = Int-Adjustment;
+ llvm::APSInt Upper = Max-Adjustment;
+
+ RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
+ return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
+}
+
+const GRState*
+RangeConstraintManager::assumeSymLE(const GRState* state, SymbolRef sym,
+ const llvm::APSInt& Int,
+ const llvm::APSInt& Adjustment) {
+ BasicValueFactory &BV = state->getBasicVals();
+
+ QualType T = state->getSymbolManager().getType(sym);
+ const llvm::APSInt &Max = BV.getMaxValue(T);
+
+ // Special case for Int == Max. This is always feasible.
+ if (Int == Max)
+ return state;
+
+ const llvm::APSInt &Min = BV.getMinValue(T);
+
+ llvm::APSInt Lower = Min-Adjustment;
+ llvm::APSInt Upper = Int-Adjustment;
+
+ RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
+ return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
+}
+
+//===------------------------------------------------------------------------===
+// Pretty-printing.
+//===------------------------------------------------------------------------===/
+
+void RangeConstraintManager::print(const GRState* St, llvm::raw_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);
+ }
+}