llvm-project/clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp

790 lines
30 KiB
C++

//== RangeConstraintManager.cpp - Manage range constraints.------*- C++ -*--==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines RangeConstraintManager, a class that tracks simple
// equality and inequality constraints on symbolic values of ProgramState.
//
//===----------------------------------------------------------------------===//
#include "clang/Basic/JsonSupport.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/RangedConstraintManager.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/ImmutableSet.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
void RangeSet::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);
}
}
}
const llvm::APSInt &RangeSet::getMinValue() const {
assert(!isEmpty());
return ranges.begin()->From();
}
bool RangeSet::pin(llvm::APSInt &Lower, llvm::APSInt &Upper) const {
// This function has nine cases, the cartesian product of range-testing
// both the upper and lower bounds against the symbol's type.
// Each case requires a different pinning operation.
// The function returns false if the described range is entirely outside
// the range of values for the associated symbol.
APSIntType Type(getMinValue());
APSIntType::RangeTestResultKind LowerTest = Type.testInRange(Lower, true);
APSIntType::RangeTestResultKind UpperTest = Type.testInRange(Upper, true);
switch (LowerTest) {
case APSIntType::RTR_Below:
switch (UpperTest) {
case APSIntType::RTR_Below:
// The entire range is outside the symbol's set of possible values.
// If this is a conventionally-ordered range, the state is infeasible.
if (Lower <= Upper)
return false;
// However, if the range wraps around, it spans all possible values.
Lower = Type.getMinValue();
Upper = Type.getMaxValue();
break;
case APSIntType::RTR_Within:
// The range starts below what's possible but ends within it. Pin.
Lower = Type.getMinValue();
Type.apply(Upper);
break;
case APSIntType::RTR_Above:
// The range spans all possible values for the symbol. Pin.
Lower = Type.getMinValue();
Upper = Type.getMaxValue();
break;
}
break;
case APSIntType::RTR_Within:
switch (UpperTest) {
case APSIntType::RTR_Below:
// The range wraps around, but all lower values are not possible.
Type.apply(Lower);
Upper = Type.getMaxValue();
break;
case APSIntType::RTR_Within:
// The range may or may not wrap around, but both limits are valid.
Type.apply(Lower);
Type.apply(Upper);
break;
case APSIntType::RTR_Above:
// The range starts within what's possible but ends above it. Pin.
Type.apply(Lower);
Upper = Type.getMaxValue();
break;
}
break;
case APSIntType::RTR_Above:
switch (UpperTest) {
case APSIntType::RTR_Below:
// The range wraps but is outside the symbol's set of possible values.
return false;
case APSIntType::RTR_Within:
// The range starts above what's possible but ends within it (wrap).
Lower = Type.getMinValue();
Type.apply(Upper);
break;
case APSIntType::RTR_Above:
// The entire range is outside the symbol's set of possible values.
// If this is a conventionally-ordered range, the state is infeasible.
if (Lower <= Upper)
return false;
// However, if the range wraps around, it spans all possible values.
Lower = Type.getMinValue();
Upper = Type.getMaxValue();
break;
}
break;
}
return true;
}
// 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 RangeSet::Intersect(BasicValueFactory &BV, Factory &F,
llvm::APSInt Lower, llvm::APSInt Upper) const {
if (!pin(Lower, Upper))
return F.getEmptySet();
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;
}
// Returns a set containing the values in the receiving set, intersected with
// the range set passed as parameter.
RangeSet RangeSet::Intersect(BasicValueFactory &BV, Factory &F,
const RangeSet &Other) const {
PrimRangeSet newRanges = F.getEmptySet();
for (iterator i = Other.begin(), e = Other.end(); i != e; ++i) {
RangeSet newPiece = Intersect(BV, F, i->From(), i->To());
for (iterator j = newPiece.begin(), ee = newPiece.end(); j != ee; ++j) {
newRanges = F.add(newRanges, *j);
}
}
return newRanges;
}
// Turn all [A, B] ranges to [-B, -A]. Ranges [MIN, B] are turned to range set
// [MIN, MIN] U [-B, MAX], when MIN and MAX are the minimal and the maximal
// signed values of the type.
RangeSet RangeSet::Negate(BasicValueFactory &BV, Factory &F) const {
PrimRangeSet newRanges = F.getEmptySet();
for (iterator i = begin(), e = end(); i != e; ++i) {
const llvm::APSInt &from = i->From(), &to = i->To();
const llvm::APSInt &newTo = (from.isMinSignedValue() ?
BV.getMaxValue(from) :
BV.getValue(- from));
if (to.isMaxSignedValue() && !newRanges.isEmpty() &&
newRanges.begin()->From().isMinSignedValue()) {
assert(newRanges.begin()->To().isMinSignedValue() &&
"Ranges should not overlap");
assert(!from.isMinSignedValue() && "Ranges should not overlap");
const llvm::APSInt &newFrom = newRanges.begin()->From();
newRanges =
F.add(F.remove(newRanges, *newRanges.begin()), Range(newFrom, newTo));
} else if (!to.isMinSignedValue()) {
const llvm::APSInt &newFrom = BV.getValue(- to);
newRanges = F.add(newRanges, Range(newFrom, newTo));
}
if (from.isMinSignedValue()) {
newRanges = F.add(newRanges, Range(BV.getMinValue(from),
BV.getMinValue(from)));
}
}
return newRanges;
}
void RangeSet::print(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 << " }";
}
namespace {
class RangeConstraintManager : public RangedConstraintManager {
public:
RangeConstraintManager(SubEngine *SE, SValBuilder &SVB)
: RangedConstraintManager(SE, SVB) {}
//===------------------------------------------------------------------===//
// Implementation for interface from ConstraintManager.
//===------------------------------------------------------------------===//
bool haveEqualConstraints(ProgramStateRef S1,
ProgramStateRef S2) const override {
return S1->get<ConstraintRange>() == S2->get<ConstraintRange>();
}
bool canReasonAbout(SVal X) const override;
ConditionTruthVal checkNull(ProgramStateRef State, SymbolRef Sym) override;
const llvm::APSInt *getSymVal(ProgramStateRef State,
SymbolRef Sym) const override;
ProgramStateRef removeDeadBindings(ProgramStateRef State,
SymbolReaper &SymReaper) override;
void printJson(raw_ostream &Out, ProgramStateRef State, const char *NL = "\n",
unsigned int Space = 0, bool IsDot = false) const override;
//===------------------------------------------------------------------===//
// Implementation for interface from RangedConstraintManager.
//===------------------------------------------------------------------===//
ProgramStateRef assumeSymNE(ProgramStateRef State, SymbolRef Sym,
const llvm::APSInt &V,
const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymEQ(ProgramStateRef State, SymbolRef Sym,
const llvm::APSInt &V,
const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymLT(ProgramStateRef State, SymbolRef Sym,
const llvm::APSInt &V,
const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymGT(ProgramStateRef State, SymbolRef Sym,
const llvm::APSInt &V,
const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymLE(ProgramStateRef State, SymbolRef Sym,
const llvm::APSInt &V,
const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymGE(ProgramStateRef State, SymbolRef Sym,
const llvm::APSInt &V,
const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymWithinInclusiveRange(
ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
const llvm::APSInt &To, const llvm::APSInt &Adjustment) override;
ProgramStateRef assumeSymOutsideInclusiveRange(
ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
const llvm::APSInt &To, const llvm::APSInt &Adjustment) override;
private:
RangeSet::Factory F;
RangeSet getRange(ProgramStateRef State, SymbolRef Sym);
const RangeSet* getRangeForMinusSymbol(ProgramStateRef State,
SymbolRef Sym);
RangeSet getSymLTRange(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment);
RangeSet getSymGTRange(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment);
RangeSet getSymLERange(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment);
RangeSet getSymLERange(llvm::function_ref<RangeSet()> RS,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment);
RangeSet getSymGERange(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment);
};
} // end anonymous namespace
std::unique_ptr<ConstraintManager>
ento::CreateRangeConstraintManager(ProgramStateManager &StMgr, SubEngine *Eng) {
return llvm::make_unique<RangeConstraintManager>(Eng, StMgr.getSValBuilder());
}
bool RangeConstraintManager::canReasonAbout(SVal X) const {
Optional<nonloc::SymbolVal> SymVal = X.getAs<nonloc::SymbolVal>();
if (SymVal && SymVal->isExpression()) {
const SymExpr *SE = SymVal->getSymbol();
if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SE)) {
switch (SIE->getOpcode()) {
// We don't reason yet about bitwise-constraints on symbolic values.
case BO_And:
case BO_Or:
case BO_Xor:
return false;
// We don't reason yet about these arithmetic constraints on
// symbolic values.
case BO_Mul:
case BO_Div:
case BO_Rem:
case BO_Shl:
case BO_Shr:
return false;
// All other cases.
default:
return true;
}
}
if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) {
// FIXME: Handle <=> here.
if (BinaryOperator::isEqualityOp(SSE->getOpcode()) ||
BinaryOperator::isRelationalOp(SSE->getOpcode())) {
// We handle Loc <> Loc comparisons, but not (yet) NonLoc <> NonLoc.
// We've recently started producing Loc <> NonLoc comparisons (that
// result from casts of one of the operands between eg. intptr_t and
// void *), but we can't reason about them yet.
if (Loc::isLocType(SSE->getLHS()->getType())) {
return Loc::isLocType(SSE->getRHS()->getType());
}
}
}
return false;
}
return true;
}
ConditionTruthVal RangeConstraintManager::checkNull(ProgramStateRef State,
SymbolRef Sym) {
const RangeSet *Ranges = State->get<ConstraintRange>(Sym);
// If we don't have any information about this symbol, it's underconstrained.
if (!Ranges)
return ConditionTruthVal();
// If we have a concrete value, see if it's zero.
if (const llvm::APSInt *Value = Ranges->getConcreteValue())
return *Value == 0;
BasicValueFactory &BV = getBasicVals();
APSIntType IntType = BV.getAPSIntType(Sym->getType());
llvm::APSInt Zero = IntType.getZeroValue();
// Check if zero is in the set of possible values.
if (Ranges->Intersect(BV, F, Zero, Zero).isEmpty())
return false;
// Zero is a possible value, but it is not the /only/ possible value.
return ConditionTruthVal();
}
const llvm::APSInt *RangeConstraintManager::getSymVal(ProgramStateRef St,
SymbolRef Sym) const {
const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(Sym);
return T ? T->getConcreteValue() : nullptr;
}
/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef
RangeConstraintManager::removeDeadBindings(ProgramStateRef State,
SymbolReaper &SymReaper) {
bool Changed = false;
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.isDead(Sym)) {
Changed = true;
CR = CRFactory.remove(CR, Sym);
}
}
return Changed ? State->set<ConstraintRange>(CR) : State;
}
/// Return a range set subtracting zero from \p Domain.
static RangeSet assumeNonZero(
BasicValueFactory &BV,
RangeSet::Factory &F,
SymbolRef Sym,
RangeSet Domain) {
APSIntType IntType = BV.getAPSIntType(Sym->getType());
return Domain.Intersect(BV, F, ++IntType.getZeroValue(),
--IntType.getZeroValue());
}
/// Apply implicit constraints for bitwise OR- and AND-.
/// For unsigned types, bitwise OR with a constant always returns
/// a value greater-or-equal than the constant, and bitwise AND
/// returns a value less-or-equal then the constant.
///
/// Pattern matches the expression \p Sym against those rule,
/// and applies the required constraints.
/// \p Input Previously established expression range set
static RangeSet applyBitwiseConstraints(
BasicValueFactory &BV,
RangeSet::Factory &F,
RangeSet Input,
const SymIntExpr* SIE) {
QualType T = SIE->getType();
bool IsUnsigned = T->isUnsignedIntegerType();
const llvm::APSInt &RHS = SIE->getRHS();
const llvm::APSInt &Zero = BV.getAPSIntType(T).getZeroValue();
BinaryOperator::Opcode Operator = SIE->getOpcode();
// For unsigned types, the output of bitwise-or is bigger-or-equal than RHS.
if (Operator == BO_Or && IsUnsigned)
return Input.Intersect(BV, F, RHS, BV.getMaxValue(T));
// Bitwise-or with a non-zero constant is always non-zero.
if (Operator == BO_Or && RHS != Zero)
return assumeNonZero(BV, F, SIE, Input);
// For unsigned types, or positive RHS,
// bitwise-and output is always smaller-or-equal than RHS (assuming two's
// complement representation of signed types).
if (Operator == BO_And && (IsUnsigned || RHS >= Zero))
return Input.Intersect(BV, F, BV.getMinValue(T), RHS);
return Input;
}
RangeSet RangeConstraintManager::getRange(ProgramStateRef State,
SymbolRef Sym) {
ConstraintRangeTy::data_type *V = State->get<ConstraintRange>(Sym);
// If Sym is a difference of symbols A - B, then maybe we have range set
// stored for B - A.
BasicValueFactory &BV = getBasicVals();
const RangeSet *R = getRangeForMinusSymbol(State, Sym);
// If we have range set stored for both A - B and B - A then calculate the
// effective range set by intersecting the range set for A - B and the
// negated range set of B - A.
if (V && R)
return V->Intersect(BV, F, R->Negate(BV, F));
if (V)
return *V;
if (R)
return R->Negate(BV, F);
// Lazily generate a new RangeSet representing all possible values for the
// given symbol type.
QualType T = Sym->getType();
RangeSet Result(F, BV.getMinValue(T), BV.getMaxValue(T));
// References are known to be non-zero.
if (T->isReferenceType())
return assumeNonZero(BV, F, Sym, Result);
// Known constraints on ranges of bitwise expressions.
if (const SymIntExpr* SIE = dyn_cast<SymIntExpr>(Sym))
return applyBitwiseConstraints(BV, F, Result, SIE);
return Result;
}
// FIXME: Once SValBuilder supports unary minus, we should use SValBuilder to
// obtain the negated symbolic expression instead of constructing the
// symbol manually. This will allow us to support finding ranges of not
// only negated SymSymExpr-type expressions, but also of other, simpler
// expressions which we currently do not know how to negate.
const RangeSet*
RangeConstraintManager::getRangeForMinusSymbol(ProgramStateRef State,
SymbolRef Sym) {
if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(Sym)) {
if (SSE->getOpcode() == BO_Sub) {
QualType T = Sym->getType();
SymbolManager &SymMgr = State->getSymbolManager();
SymbolRef negSym = SymMgr.getSymSymExpr(SSE->getRHS(), BO_Sub,
SSE->getLHS(), T);
if (const RangeSet *negV = State->get<ConstraintRange>(negSym)) {
// Unsigned range set cannot be negated, unless it is [0, 0].
if ((negV->getConcreteValue() &&
(*negV->getConcreteValue() == 0)) ||
T->isSignedIntegerOrEnumerationType())
return negV;
}
}
}
return nullptr;
}
//===------------------------------------------------------------------------===
// assumeSymX methods: protected 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.
ProgramStateRef
RangeConstraintManager::assumeSymNE(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
// Before we do any real work, see if the value can even show up.
APSIntType AdjustmentType(Adjustment);
if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
return St;
llvm::APSInt Lower = AdjustmentType.convert(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(St, Sym).Intersect(getBasicVals(), F, Upper, Lower);
return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
}
ProgramStateRef
RangeConstraintManager::assumeSymEQ(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
// Before we do any real work, see if the value can even show up.
APSIntType AdjustmentType(Adjustment);
if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
return nullptr;
// [Int-Adjustment, Int-Adjustment]
llvm::APSInt AdjInt = AdjustmentType.convert(Int) - Adjustment;
RangeSet New = getRange(St, Sym).Intersect(getBasicVals(), F, AdjInt, AdjInt);
return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
}
RangeSet RangeConstraintManager::getSymLTRange(ProgramStateRef St,
SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
// Before we do any real work, see if the value can even show up.
APSIntType AdjustmentType(Adjustment);
switch (AdjustmentType.testInRange(Int, true)) {
case APSIntType::RTR_Below:
return F.getEmptySet();
case APSIntType::RTR_Within:
break;
case APSIntType::RTR_Above:
return getRange(St, Sym);
}
// Special case for Int == Min. This is always false.
llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
llvm::APSInt Min = AdjustmentType.getMinValue();
if (ComparisonVal == Min)
return F.getEmptySet();
llvm::APSInt Lower = Min - Adjustment;
llvm::APSInt Upper = ComparisonVal - Adjustment;
--Upper;
return getRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
}
ProgramStateRef
RangeConstraintManager::assumeSymLT(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
RangeSet New = getSymLTRange(St, Sym, Int, Adjustment);
return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
}
RangeSet RangeConstraintManager::getSymGTRange(ProgramStateRef St,
SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
// Before we do any real work, see if the value can even show up.
APSIntType AdjustmentType(Adjustment);
switch (AdjustmentType.testInRange(Int, true)) {
case APSIntType::RTR_Below:
return getRange(St, Sym);
case APSIntType::RTR_Within:
break;
case APSIntType::RTR_Above:
return F.getEmptySet();
}
// Special case for Int == Max. This is always false.
llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
llvm::APSInt Max = AdjustmentType.getMaxValue();
if (ComparisonVal == Max)
return F.getEmptySet();
llvm::APSInt Lower = ComparisonVal - Adjustment;
llvm::APSInt Upper = Max - Adjustment;
++Lower;
return getRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
}
ProgramStateRef
RangeConstraintManager::assumeSymGT(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
RangeSet New = getSymGTRange(St, Sym, Int, Adjustment);
return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
}
RangeSet RangeConstraintManager::getSymGERange(ProgramStateRef St,
SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
// Before we do any real work, see if the value can even show up.
APSIntType AdjustmentType(Adjustment);
switch (AdjustmentType.testInRange(Int, true)) {
case APSIntType::RTR_Below:
return getRange(St, Sym);
case APSIntType::RTR_Within:
break;
case APSIntType::RTR_Above:
return F.getEmptySet();
}
// Special case for Int == Min. This is always feasible.
llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
llvm::APSInt Min = AdjustmentType.getMinValue();
if (ComparisonVal == Min)
return getRange(St, Sym);
llvm::APSInt Max = AdjustmentType.getMaxValue();
llvm::APSInt Lower = ComparisonVal - Adjustment;
llvm::APSInt Upper = Max - Adjustment;
return getRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
}
ProgramStateRef
RangeConstraintManager::assumeSymGE(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
RangeSet New = getSymGERange(St, Sym, Int, Adjustment);
return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
}
RangeSet RangeConstraintManager::getSymLERange(
llvm::function_ref<RangeSet()> RS,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
// Before we do any real work, see if the value can even show up.
APSIntType AdjustmentType(Adjustment);
switch (AdjustmentType.testInRange(Int, true)) {
case APSIntType::RTR_Below:
return F.getEmptySet();
case APSIntType::RTR_Within:
break;
case APSIntType::RTR_Above:
return RS();
}
// Special case for Int == Max. This is always feasible.
llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
llvm::APSInt Max = AdjustmentType.getMaxValue();
if (ComparisonVal == Max)
return RS();
llvm::APSInt Min = AdjustmentType.getMinValue();
llvm::APSInt Lower = Min - Adjustment;
llvm::APSInt Upper = ComparisonVal - Adjustment;
return RS().Intersect(getBasicVals(), F, Lower, Upper);
}
RangeSet RangeConstraintManager::getSymLERange(ProgramStateRef St,
SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
return getSymLERange([&] { return getRange(St, Sym); }, Int, Adjustment);
}
ProgramStateRef
RangeConstraintManager::assumeSymLE(ProgramStateRef St, SymbolRef Sym,
const llvm::APSInt &Int,
const llvm::APSInt &Adjustment) {
RangeSet New = getSymLERange(St, Sym, Int, Adjustment);
return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
}
ProgramStateRef RangeConstraintManager::assumeSymWithinInclusiveRange(
ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
const llvm::APSInt &To, const llvm::APSInt &Adjustment) {
RangeSet New = getSymGERange(State, Sym, From, Adjustment);
if (New.isEmpty())
return nullptr;
RangeSet Out = getSymLERange([&] { return New; }, To, Adjustment);
return Out.isEmpty() ? nullptr : State->set<ConstraintRange>(Sym, Out);
}
ProgramStateRef RangeConstraintManager::assumeSymOutsideInclusiveRange(
ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
const llvm::APSInt &To, const llvm::APSInt &Adjustment) {
RangeSet RangeLT = getSymLTRange(State, Sym, From, Adjustment);
RangeSet RangeGT = getSymGTRange(State, Sym, To, Adjustment);
RangeSet New(RangeLT.addRange(F, RangeGT));
return New.isEmpty() ? nullptr : State->set<ConstraintRange>(Sym, New);
}
//===----------------------------------------------------------------------===//
// Pretty-printing.
//===----------------------------------------------------------------------===//
void RangeConstraintManager::printJson(raw_ostream &Out, ProgramStateRef State,
const char *NL, unsigned int Space,
bool IsDot) const {
ConstraintRangeTy Constraints = State->get<ConstraintRange>();
Indent(Out, Space, IsDot) << "\"constraints\": ";
if (Constraints.isEmpty()) {
Out << "null," << NL;
return;
}
++Space;
Out << '[' << NL;
for (ConstraintRangeTy::iterator I = Constraints.begin();
I != Constraints.end(); ++I) {
Indent(Out, Space, IsDot)
<< "{ \"symbol\": \"" << I.getKey() << "\", \"range\": \"";
I.getData().print(Out);
Out << "\" }";
if (std::next(I) != Constraints.end())
Out << ',';
Out << NL;
}
--Space;
Indent(Out, Space, IsDot) << "]," << NL;
}