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/SimpleSValBuilder.cpp b/lib/StaticAnalyzer/SimpleSValBuilder.cpp
new file mode 100644
index 0000000..f1a9074
--- /dev/null
+++ b/lib/StaticAnalyzer/SimpleSValBuilder.cpp
@@ -0,0 +1,884 @@
+// SimpleSValBuilder.cpp - A basic SValBuilder -----------------------*- 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 SimpleSValBuilder, a basic implementation of SValBuilder.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/PathSensitive/SValBuilder.h"
+#include "clang/StaticAnalyzer/PathSensitive/GRState.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class SimpleSValBuilder : public SValBuilder {
+protected:
+ virtual SVal evalCastNL(NonLoc val, QualType castTy);
+ virtual SVal evalCastL(Loc val, QualType castTy);
+
+public:
+ SimpleSValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,
+ GRStateManager &stateMgr)
+ : SValBuilder(alloc, context, stateMgr) {}
+ virtual ~SimpleSValBuilder() {}
+
+ virtual SVal evalMinus(NonLoc val);
+ virtual SVal evalComplement(NonLoc val);
+ virtual SVal evalBinOpNN(const GRState *state, BinaryOperator::Opcode op,
+ NonLoc lhs, NonLoc rhs, QualType resultTy);
+ virtual SVal evalBinOpLL(const GRState *state, BinaryOperator::Opcode op,
+ Loc lhs, Loc rhs, QualType resultTy);
+ virtual SVal evalBinOpLN(const GRState *state, BinaryOperator::Opcode op,
+ Loc lhs, NonLoc rhs, QualType resultTy);
+
+ /// getKnownValue - evaluates a given SVal. If the SVal has only one possible
+ /// (integer) value, that value is returned. Otherwise, returns NULL.
+ virtual const llvm::APSInt *getKnownValue(const GRState *state, SVal V);
+
+ SVal MakeSymIntVal(const SymExpr *LHS, BinaryOperator::Opcode op,
+ const llvm::APSInt &RHS, QualType resultTy);
+};
+} // end anonymous namespace
+
+SValBuilder *ento::createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
+ ASTContext &context,
+ GRStateManager &stateMgr) {
+ return new SimpleSValBuilder(alloc, context, stateMgr);
+}
+
+//===----------------------------------------------------------------------===//
+// Transfer function for Casts.
+//===----------------------------------------------------------------------===//
+
+SVal SimpleSValBuilder::evalCastNL(NonLoc val, QualType castTy) {
+
+ bool isLocType = Loc::IsLocType(castTy);
+
+ if (nonloc::LocAsInteger *LI = dyn_cast<nonloc::LocAsInteger>(&val)) {
+ if (isLocType)
+ return LI->getLoc();
+
+ // FIXME: Correctly support promotions/truncations.
+ unsigned castSize = Context.getTypeSize(castTy);
+ if (castSize == LI->getNumBits())
+ return val;
+ return makeLocAsInteger(LI->getLoc(), castSize);
+ }
+
+ if (const SymExpr *se = val.getAsSymbolicExpression()) {
+ QualType T = Context.getCanonicalType(se->getType(Context));
+ if (T == Context.getCanonicalType(castTy))
+ return val;
+
+ // FIXME: Remove this hack when we support symbolic truncation/extension.
+ // HACK: If both castTy and T are integers, ignore the cast. This is
+ // not a permanent solution. Eventually we want to precisely handle
+ // extension/truncation of symbolic integers. This prevents us from losing
+ // precision when we assign 'x = y' and 'y' is symbolic and x and y are
+ // different integer types.
+ if (T->isIntegerType() && castTy->isIntegerType())
+ return val;
+
+ return UnknownVal();
+ }
+
+ if (!isa<nonloc::ConcreteInt>(val))
+ return UnknownVal();
+
+ // Only handle casts from integers to integers.
+ if (!isLocType && !castTy->isIntegerType())
+ return UnknownVal();
+
+ llvm::APSInt i = cast<nonloc::ConcreteInt>(val).getValue();
+ i.setIsUnsigned(castTy->isUnsignedIntegerType() || Loc::IsLocType(castTy));
+ i = i.extOrTrunc(Context.getTypeSize(castTy));
+
+ if (isLocType)
+ return makeIntLocVal(i);
+ else
+ return makeIntVal(i);
+}
+
+SVal SimpleSValBuilder::evalCastL(Loc val, QualType castTy) {
+
+ // Casts from pointers -> pointers, just return the lval.
+ //
+ // Casts from pointers -> references, just return the lval. These
+ // can be introduced by the frontend for corner cases, e.g
+ // casting from va_list* to __builtin_va_list&.
+ //
+ if (Loc::IsLocType(castTy) || castTy->isReferenceType())
+ return val;
+
+ // FIXME: Handle transparent unions where a value can be "transparently"
+ // lifted into a union type.
+ if (castTy->isUnionType())
+ return UnknownVal();
+
+ if (castTy->isIntegerType()) {
+ unsigned BitWidth = Context.getTypeSize(castTy);
+
+ if (!isa<loc::ConcreteInt>(val))
+ return makeLocAsInteger(val, BitWidth);
+
+ llvm::APSInt i = cast<loc::ConcreteInt>(val).getValue();
+ i.setIsUnsigned(castTy->isUnsignedIntegerType() || Loc::IsLocType(castTy));
+ i = i.extOrTrunc(BitWidth);
+ return makeIntVal(i);
+ }
+
+ // All other cases: return 'UnknownVal'. This includes casting pointers
+ // to floats, which is probably badness it itself, but this is a good
+ // intermediate solution until we do something better.
+ return UnknownVal();
+}
+
+//===----------------------------------------------------------------------===//
+// Transfer function for unary operators.
+//===----------------------------------------------------------------------===//
+
+SVal SimpleSValBuilder::evalMinus(NonLoc val) {
+ switch (val.getSubKind()) {
+ case nonloc::ConcreteIntKind:
+ return cast<nonloc::ConcreteInt>(val).evalMinus(*this);
+ default:
+ return UnknownVal();
+ }
+}
+
+SVal SimpleSValBuilder::evalComplement(NonLoc X) {
+ switch (X.getSubKind()) {
+ case nonloc::ConcreteIntKind:
+ return cast<nonloc::ConcreteInt>(X).evalComplement(*this);
+ default:
+ return UnknownVal();
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// Transfer function for binary operators.
+//===----------------------------------------------------------------------===//
+
+static BinaryOperator::Opcode NegateComparison(BinaryOperator::Opcode op) {
+ switch (op) {
+ default:
+ assert(false && "Invalid opcode.");
+ case BO_LT: return BO_GE;
+ case BO_GT: return BO_LE;
+ case BO_LE: return BO_GT;
+ case BO_GE: return BO_LT;
+ case BO_EQ: return BO_NE;
+ case BO_NE: return BO_EQ;
+ }
+}
+
+static BinaryOperator::Opcode ReverseComparison(BinaryOperator::Opcode op) {
+ switch (op) {
+ default:
+ assert(false && "Invalid opcode.");
+ case BO_LT: return BO_GT;
+ case BO_GT: return BO_LT;
+ case BO_LE: return BO_GE;
+ case BO_GE: return BO_LE;
+ case BO_EQ:
+ case BO_NE:
+ return op;
+ }
+}
+
+SVal SimpleSValBuilder::MakeSymIntVal(const SymExpr *LHS,
+ BinaryOperator::Opcode op,
+ const llvm::APSInt &RHS,
+ QualType resultTy) {
+ bool isIdempotent = false;
+
+ // Check for a few special cases with known reductions first.
+ switch (op) {
+ default:
+ // We can't reduce this case; just treat it normally.
+ break;
+ case BO_Mul:
+ // a*0 and a*1
+ if (RHS == 0)
+ return makeIntVal(0, resultTy);
+ else if (RHS == 1)
+ isIdempotent = true;
+ break;
+ case BO_Div:
+ // a/0 and a/1
+ if (RHS == 0)
+ // This is also handled elsewhere.
+ return UndefinedVal();
+ else if (RHS == 1)
+ isIdempotent = true;
+ break;
+ case BO_Rem:
+ // a%0 and a%1
+ if (RHS == 0)
+ // This is also handled elsewhere.
+ return UndefinedVal();
+ else if (RHS == 1)
+ return makeIntVal(0, resultTy);
+ break;
+ case BO_Add:
+ case BO_Sub:
+ case BO_Shl:
+ case BO_Shr:
+ case BO_Xor:
+ // a+0, a-0, a<<0, a>>0, a^0
+ if (RHS == 0)
+ isIdempotent = true;
+ break;
+ case BO_And:
+ // a&0 and a&(~0)
+ if (RHS == 0)
+ return makeIntVal(0, resultTy);
+ else if (RHS.isAllOnesValue())
+ isIdempotent = true;
+ break;
+ case BO_Or:
+ // a|0 and a|(~0)
+ if (RHS == 0)
+ isIdempotent = true;
+ else if (RHS.isAllOnesValue()) {
+ const llvm::APSInt &Result = BasicVals.Convert(resultTy, RHS);
+ return nonloc::ConcreteInt(Result);
+ }
+ break;
+ }
+
+ // Idempotent ops (like a*1) can still change the type of an expression.
+ // Wrap the LHS up in a NonLoc again and let evalCastNL do the dirty work.
+ if (isIdempotent) {
+ if (SymbolRef LHSSym = dyn_cast<SymbolData>(LHS))
+ return evalCastNL(nonloc::SymbolVal(LHSSym), resultTy);
+ return evalCastNL(nonloc::SymExprVal(LHS), resultTy);
+ }
+
+ // If we reach this point, the expression cannot be simplified.
+ // Make a SymExprVal for the entire thing.
+ return makeNonLoc(LHS, op, RHS, resultTy);
+}
+
+SVal SimpleSValBuilder::evalBinOpNN(const GRState *state,
+ BinaryOperator::Opcode op,
+ NonLoc lhs, NonLoc rhs,
+ QualType resultTy) {
+ // Handle trivial case where left-side and right-side are the same.
+ if (lhs == rhs)
+ switch (op) {
+ default:
+ break;
+ case BO_EQ:
+ case BO_LE:
+ case BO_GE:
+ return makeTruthVal(true, resultTy);
+ case BO_LT:
+ case BO_GT:
+ case BO_NE:
+ return makeTruthVal(false, resultTy);
+ case BO_Xor:
+ case BO_Sub:
+ return makeIntVal(0, resultTy);
+ case BO_Or:
+ case BO_And:
+ return evalCastNL(lhs, resultTy);
+ }
+
+ while (1) {
+ switch (lhs.getSubKind()) {
+ default:
+ return UnknownVal();
+ case nonloc::LocAsIntegerKind: {
+ Loc lhsL = cast<nonloc::LocAsInteger>(lhs).getLoc();
+ switch (rhs.getSubKind()) {
+ case nonloc::LocAsIntegerKind:
+ return evalBinOpLL(state, op, lhsL,
+ cast<nonloc::LocAsInteger>(rhs).getLoc(),
+ resultTy);
+ case nonloc::ConcreteIntKind: {
+ // Transform the integer into a location and compare.
+ llvm::APSInt i = cast<nonloc::ConcreteInt>(rhs).getValue();
+ i.setIsUnsigned(true);
+ i = i.extOrTrunc(Context.getTypeSize(Context.VoidPtrTy));
+ return evalBinOpLL(state, op, lhsL, makeLoc(i), resultTy);
+ }
+ default:
+ switch (op) {
+ case BO_EQ:
+ return makeTruthVal(false, resultTy);
+ case BO_NE:
+ return makeTruthVal(true, resultTy);
+ default:
+ // This case also handles pointer arithmetic.
+ return UnknownVal();
+ }
+ }
+ }
+ case nonloc::SymExprValKind: {
+ nonloc::SymExprVal *selhs = cast<nonloc::SymExprVal>(&lhs);
+
+ // Only handle LHS of the form "$sym op constant", at least for now.
+ const SymIntExpr *symIntExpr =
+ dyn_cast<SymIntExpr>(selhs->getSymbolicExpression());
+
+ if (!symIntExpr)
+ return UnknownVal();
+
+ // Is this a logical not? (!x is represented as x == 0.)
+ if (op == BO_EQ && rhs.isZeroConstant()) {
+ // We know how to negate certain expressions. Simplify them here.
+
+ BinaryOperator::Opcode opc = symIntExpr->getOpcode();
+ switch (opc) {
+ default:
+ // We don't know how to negate this operation.
+ // Just handle it as if it were a normal comparison to 0.
+ break;
+ case BO_LAnd:
+ case BO_LOr:
+ assert(false && "Logical operators handled by branching logic.");
+ return UnknownVal();
+ case BO_Assign:
+ case BO_MulAssign:
+ case BO_DivAssign:
+ case BO_RemAssign:
+ case BO_AddAssign:
+ case BO_SubAssign:
+ case BO_ShlAssign:
+ case BO_ShrAssign:
+ case BO_AndAssign:
+ case BO_XorAssign:
+ case BO_OrAssign:
+ case BO_Comma:
+ assert(false && "'=' and ',' operators handled by ExprEngine.");
+ return UnknownVal();
+ case BO_PtrMemD:
+ case BO_PtrMemI:
+ assert(false && "Pointer arithmetic not handled here.");
+ return UnknownVal();
+ case BO_LT:
+ case BO_GT:
+ case BO_LE:
+ case BO_GE:
+ case BO_EQ:
+ case BO_NE:
+ // Negate the comparison and make a value.
+ opc = NegateComparison(opc);
+ assert(symIntExpr->getType(Context) == resultTy);
+ return makeNonLoc(symIntExpr->getLHS(), opc,
+ symIntExpr->getRHS(), resultTy);
+ }
+ }
+
+ // For now, only handle expressions whose RHS is a constant.
+ const nonloc::ConcreteInt *rhsInt = dyn_cast<nonloc::ConcreteInt>(&rhs);
+ if (!rhsInt)
+ return UnknownVal();
+
+ // If both the LHS and the current expression are additive,
+ // fold their constants.
+ if (BinaryOperator::isAdditiveOp(op)) {
+ BinaryOperator::Opcode lop = symIntExpr->getOpcode();
+ if (BinaryOperator::isAdditiveOp(lop)) {
+ // resultTy may not be the best type to convert to, but it's
+ // probably the best choice in expressions with mixed type
+ // (such as x+1U+2LL). The rules for implicit conversions should
+ // choose a reasonable type to preserve the expression, and will
+ // at least match how the value is going to be used.
+ const llvm::APSInt &first =
+ BasicVals.Convert(resultTy, symIntExpr->getRHS());
+ const llvm::APSInt &second =
+ BasicVals.Convert(resultTy, rhsInt->getValue());
+ const llvm::APSInt *newRHS;
+ if (lop == op)
+ newRHS = BasicVals.evalAPSInt(BO_Add, first, second);
+ else
+ newRHS = BasicVals.evalAPSInt(BO_Sub, first, second);
+ return MakeSymIntVal(symIntExpr->getLHS(), lop, *newRHS, resultTy);
+ }
+ }
+
+ // Otherwise, make a SymExprVal out of the expression.
+ return MakeSymIntVal(symIntExpr, op, rhsInt->getValue(), resultTy);
+ }
+ case nonloc::ConcreteIntKind: {
+ const nonloc::ConcreteInt& lhsInt = cast<nonloc::ConcreteInt>(lhs);
+
+ if (isa<nonloc::ConcreteInt>(rhs)) {
+ return lhsInt.evalBinOp(*this, op, cast<nonloc::ConcreteInt>(rhs));
+ } else {
+ const llvm::APSInt& lhsValue = lhsInt.getValue();
+
+ // Swap the left and right sides and flip the operator if doing so
+ // allows us to better reason about the expression (this is a form
+ // of expression canonicalization).
+ // While we're at it, catch some special cases for non-commutative ops.
+ NonLoc tmp = rhs;
+ rhs = lhs;
+ lhs = tmp;
+
+ switch (op) {
+ case BO_LT:
+ case BO_GT:
+ case BO_LE:
+ case BO_GE:
+ op = ReverseComparison(op);
+ continue;
+ case BO_EQ:
+ case BO_NE:
+ case BO_Add:
+ case BO_Mul:
+ case BO_And:
+ case BO_Xor:
+ case BO_Or:
+ continue;
+ case BO_Shr:
+ if (lhsValue.isAllOnesValue() && lhsValue.isSigned())
+ // At this point lhs and rhs have been swapped.
+ return rhs;
+ // FALL-THROUGH
+ case BO_Shl:
+ if (lhsValue == 0)
+ // At this point lhs and rhs have been swapped.
+ return rhs;
+ return UnknownVal();
+ default:
+ return UnknownVal();
+ }
+ }
+ }
+ case nonloc::SymbolValKind: {
+ nonloc::SymbolVal *slhs = cast<nonloc::SymbolVal>(&lhs);
+ SymbolRef Sym = slhs->getSymbol();
+ // Does the symbol simplify to a constant? If so, "fold" the constant
+ // by setting 'lhs' to a ConcreteInt and try again.
+ if (Sym->getType(Context)->isIntegerType())
+ if (const llvm::APSInt *Constant = state->getSymVal(Sym)) {
+ // The symbol evaluates to a constant. If necessary, promote the
+ // folded constant (LHS) to the result type.
+ const llvm::APSInt &lhs_I = BasicVals.Convert(resultTy, *Constant);
+ lhs = nonloc::ConcreteInt(lhs_I);
+
+ // Also promote the RHS (if necessary).
+
+ // For shifts, it is not necessary to promote the RHS.
+ if (BinaryOperator::isShiftOp(op))
+ continue;
+
+ // Other operators: do an implicit conversion. This shouldn't be
+ // necessary once we support truncation/extension of symbolic values.
+ if (nonloc::ConcreteInt *rhs_I = dyn_cast<nonloc::ConcreteInt>(&rhs)){
+ rhs = nonloc::ConcreteInt(BasicVals.Convert(resultTy,
+ rhs_I->getValue()));
+ }
+
+ continue;
+ }
+
+ // Is the RHS a symbol we can simplify?
+ if (const nonloc::SymbolVal *srhs = dyn_cast<nonloc::SymbolVal>(&rhs)) {
+ SymbolRef RSym = srhs->getSymbol();
+ if (RSym->getType(Context)->isIntegerType()) {
+ if (const llvm::APSInt *Constant = state->getSymVal(RSym)) {
+ // The symbol evaluates to a constant.
+ const llvm::APSInt &rhs_I = BasicVals.Convert(resultTy, *Constant);
+ rhs = nonloc::ConcreteInt(rhs_I);
+ }
+ }
+ }
+
+ if (isa<nonloc::ConcreteInt>(rhs)) {
+ return MakeSymIntVal(slhs->getSymbol(), op,
+ cast<nonloc::ConcreteInt>(rhs).getValue(),
+ resultTy);
+ }
+
+ return UnknownVal();
+ }
+ }
+ }
+}
+
+// FIXME: all this logic will change if/when we have MemRegion::getLocation().
+SVal SimpleSValBuilder::evalBinOpLL(const GRState *state,
+ BinaryOperator::Opcode op,
+ Loc lhs, Loc rhs,
+ QualType resultTy) {
+ // Only comparisons and subtractions are valid operations on two pointers.
+ // See [C99 6.5.5 through 6.5.14] or [C++0x 5.6 through 5.15].
+ // However, if a pointer is casted to an integer, evalBinOpNN may end up
+ // calling this function with another operation (PR7527). We don't attempt to
+ // model this for now, but it could be useful, particularly when the
+ // "location" is actually an integer value that's been passed through a void*.
+ if (!(BinaryOperator::isComparisonOp(op) || op == BO_Sub))
+ return UnknownVal();
+
+ // Special cases for when both sides are identical.
+ if (lhs == rhs) {
+ switch (op) {
+ default:
+ assert(false && "Unimplemented operation for two identical values");
+ return UnknownVal();
+ case BO_Sub:
+ return makeZeroVal(resultTy);
+ case BO_EQ:
+ case BO_LE:
+ case BO_GE:
+ return makeTruthVal(true, resultTy);
+ case BO_NE:
+ case BO_LT:
+ case BO_GT:
+ return makeTruthVal(false, resultTy);
+ }
+ }
+
+ switch (lhs.getSubKind()) {
+ default:
+ assert(false && "Ordering not implemented for this Loc.");
+ return UnknownVal();
+
+ case loc::GotoLabelKind:
+ // The only thing we know about labels is that they're non-null.
+ if (rhs.isZeroConstant()) {
+ switch (op) {
+ default:
+ break;
+ case BO_Sub:
+ return evalCastL(lhs, resultTy);
+ case BO_EQ:
+ case BO_LE:
+ case BO_LT:
+ return makeTruthVal(false, resultTy);
+ case BO_NE:
+ case BO_GT:
+ case BO_GE:
+ return makeTruthVal(true, resultTy);
+ }
+ }
+ // There may be two labels for the same location, and a function region may
+ // have the same address as a label at the start of the function (depending
+ // on the ABI).
+ // FIXME: we can probably do a comparison against other MemRegions, though.
+ // FIXME: is there a way to tell if two labels refer to the same location?
+ return UnknownVal();
+
+ case loc::ConcreteIntKind: {
+ // If one of the operands is a symbol and the other is a constant,
+ // build an expression for use by the constraint manager.
+ if (SymbolRef rSym = rhs.getAsLocSymbol()) {
+ // We can only build expressions with symbols on the left,
+ // so we need a reversible operator.
+ if (!BinaryOperator::isComparisonOp(op))
+ return UnknownVal();
+
+ const llvm::APSInt &lVal = cast<loc::ConcreteInt>(lhs).getValue();
+ return makeNonLoc(rSym, ReverseComparison(op), lVal, resultTy);
+ }
+
+ // If both operands are constants, just perform the operation.
+ if (loc::ConcreteInt *rInt = dyn_cast<loc::ConcreteInt>(&rhs)) {
+ SVal ResultVal = cast<loc::ConcreteInt>(lhs).evalBinOp(BasicVals, op,
+ *rInt);
+ if (Loc *Result = dyn_cast<Loc>(&ResultVal))
+ return evalCastL(*Result, resultTy);
+ else
+ return UnknownVal();
+ }
+
+ // Special case comparisons against NULL.
+ // This must come after the test if the RHS is a symbol, which is used to
+ // build constraints. The address of any non-symbolic region is guaranteed
+ // to be non-NULL, as is any label.
+ assert(isa<loc::MemRegionVal>(rhs) || isa<loc::GotoLabel>(rhs));
+ if (lhs.isZeroConstant()) {
+ switch (op) {
+ default:
+ break;
+ case BO_EQ:
+ case BO_GT:
+ case BO_GE:
+ return makeTruthVal(false, resultTy);
+ case BO_NE:
+ case BO_LT:
+ case BO_LE:
+ return makeTruthVal(true, resultTy);
+ }
+ }
+
+ // Comparing an arbitrary integer to a region or label address is
+ // completely unknowable.
+ return UnknownVal();
+ }
+ case loc::MemRegionKind: {
+ if (loc::ConcreteInt *rInt = dyn_cast<loc::ConcreteInt>(&rhs)) {
+ // If one of the operands is a symbol and the other is a constant,
+ // build an expression for use by the constraint manager.
+ if (SymbolRef lSym = lhs.getAsLocSymbol())
+ return MakeSymIntVal(lSym, op, rInt->getValue(), resultTy);
+
+ // Special case comparisons to NULL.
+ // This must come after the test if the LHS is a symbol, which is used to
+ // build constraints. The address of any non-symbolic region is guaranteed
+ // to be non-NULL.
+ if (rInt->isZeroConstant()) {
+ switch (op) {
+ default:
+ break;
+ case BO_Sub:
+ return evalCastL(lhs, resultTy);
+ case BO_EQ:
+ case BO_LT:
+ case BO_LE:
+ return makeTruthVal(false, resultTy);
+ case BO_NE:
+ case BO_GT:
+ case BO_GE:
+ return makeTruthVal(true, resultTy);
+ }
+ }
+
+ // Comparing a region to an arbitrary integer is completely unknowable.
+ return UnknownVal();
+ }
+
+ // Get both values as regions, if possible.
+ const MemRegion *LeftMR = lhs.getAsRegion();
+ assert(LeftMR && "MemRegionKind SVal doesn't have a region!");
+
+ const MemRegion *RightMR = rhs.getAsRegion();
+ if (!RightMR)
+ // The RHS is probably a label, which in theory could address a region.
+ // FIXME: we can probably make a more useful statement about non-code
+ // regions, though.
+ return UnknownVal();
+
+ // If both values wrap regions, see if they're from different base regions.
+ const MemRegion *LeftBase = LeftMR->getBaseRegion();
+ const MemRegion *RightBase = RightMR->getBaseRegion();
+ if (LeftBase != RightBase &&
+ !isa<SymbolicRegion>(LeftBase) && !isa<SymbolicRegion>(RightBase)) {
+ switch (op) {
+ default:
+ return UnknownVal();
+ case BO_EQ:
+ return makeTruthVal(false, resultTy);
+ case BO_NE:
+ return makeTruthVal(true, resultTy);
+ }
+ }
+
+ // The two regions are from the same base region. See if they're both a
+ // type of region we know how to compare.
+
+ // FIXME: If/when there is a getAsRawOffset() for FieldRegions, this
+ // ElementRegion path and the FieldRegion path below should be unified.
+ if (const ElementRegion *LeftER = dyn_cast<ElementRegion>(LeftMR)) {
+ // First see if the right region is also an ElementRegion.
+ const ElementRegion *RightER = dyn_cast<ElementRegion>(RightMR);
+ if (!RightER)
+ return UnknownVal();
+
+ // Next, see if the two ERs have the same super-region and matching types.
+ // FIXME: This should do something useful even if the types don't match,
+ // though if both indexes are constant the RegionRawOffset path will
+ // give the correct answer.
+ if (LeftER->getSuperRegion() == RightER->getSuperRegion() &&
+ LeftER->getElementType() == RightER->getElementType()) {
+ // Get the left index and cast it to the correct type.
+ // If the index is unknown or undefined, bail out here.
+ SVal LeftIndexVal = LeftER->getIndex();
+ NonLoc *LeftIndex = dyn_cast<NonLoc>(&LeftIndexVal);
+ if (!LeftIndex)
+ return UnknownVal();
+ LeftIndexVal = evalCastNL(*LeftIndex, resultTy);
+ LeftIndex = dyn_cast<NonLoc>(&LeftIndexVal);
+ if (!LeftIndex)
+ return UnknownVal();
+
+ // Do the same for the right index.
+ SVal RightIndexVal = RightER->getIndex();
+ NonLoc *RightIndex = dyn_cast<NonLoc>(&RightIndexVal);
+ if (!RightIndex)
+ return UnknownVal();
+ RightIndexVal = evalCastNL(*RightIndex, resultTy);
+ RightIndex = dyn_cast<NonLoc>(&RightIndexVal);
+ if (!RightIndex)
+ return UnknownVal();
+
+ // Actually perform the operation.
+ // evalBinOpNN expects the two indexes to already be the right type.
+ return evalBinOpNN(state, op, *LeftIndex, *RightIndex, resultTy);
+ }
+
+ // If the element indexes aren't comparable, see if the raw offsets are.
+ RegionRawOffset LeftOffset = LeftER->getAsArrayOffset();
+ RegionRawOffset RightOffset = RightER->getAsArrayOffset();
+
+ if (LeftOffset.getRegion() != NULL &&
+ LeftOffset.getRegion() == RightOffset.getRegion()) {
+ int64_t left = LeftOffset.getByteOffset();
+ int64_t right = RightOffset.getByteOffset();
+
+ switch (op) {
+ default:
+ return UnknownVal();
+ case BO_LT:
+ return makeTruthVal(left < right, resultTy);
+ case BO_GT:
+ return makeTruthVal(left > right, resultTy);
+ case BO_LE:
+ return makeTruthVal(left <= right, resultTy);
+ case BO_GE:
+ return makeTruthVal(left >= right, resultTy);
+ case BO_EQ:
+ return makeTruthVal(left == right, resultTy);
+ case BO_NE:
+ return makeTruthVal(left != right, resultTy);
+ }
+ }
+
+ // If we get here, we have no way of comparing the ElementRegions.
+ return UnknownVal();
+ }
+
+ // See if both regions are fields of the same structure.
+ // FIXME: This doesn't handle nesting, inheritance, or Objective-C ivars.
+ if (const FieldRegion *LeftFR = dyn_cast<FieldRegion>(LeftMR)) {
+ // Only comparisons are meaningful here!
+ if (!BinaryOperator::isComparisonOp(op))
+ return UnknownVal();
+
+ // First see if the right region is also a FieldRegion.
+ const FieldRegion *RightFR = dyn_cast<FieldRegion>(RightMR);
+ if (!RightFR)
+ return UnknownVal();
+
+ // Next, see if the two FRs have the same super-region.
+ // FIXME: This doesn't handle casts yet, and simply stripping the casts
+ // doesn't help.
+ if (LeftFR->getSuperRegion() != RightFR->getSuperRegion())
+ return UnknownVal();
+
+ const FieldDecl *LeftFD = LeftFR->getDecl();
+ const FieldDecl *RightFD = RightFR->getDecl();
+ const RecordDecl *RD = LeftFD->getParent();
+
+ // Make sure the two FRs are from the same kind of record. Just in case!
+ // FIXME: This is probably where inheritance would be a problem.
+ if (RD != RightFD->getParent())
+ return UnknownVal();
+
+ // We know for sure that the two fields are not the same, since that
+ // would have given us the same SVal.
+ if (op == BO_EQ)
+ return makeTruthVal(false, resultTy);
+ if (op == BO_NE)
+ return makeTruthVal(true, resultTy);
+
+ // Iterate through the fields and see which one comes first.
+ // [C99 6.7.2.1.13] "Within a structure object, the non-bit-field
+ // members and the units in which bit-fields reside have addresses that
+ // increase in the order in which they are declared."
+ bool leftFirst = (op == BO_LT || op == BO_LE);
+ for (RecordDecl::field_iterator I = RD->field_begin(),
+ E = RD->field_end(); I!=E; ++I) {
+ if (*I == LeftFD)
+ return makeTruthVal(leftFirst, resultTy);
+ if (*I == RightFD)
+ return makeTruthVal(!leftFirst, resultTy);
+ }
+
+ assert(false && "Fields not found in parent record's definition");
+ }
+
+ // If we get here, we have no way of comparing the regions.
+ return UnknownVal();
+ }
+ }
+}
+
+SVal SimpleSValBuilder::evalBinOpLN(const GRState *state,
+ BinaryOperator::Opcode op,
+ Loc lhs, NonLoc rhs, QualType resultTy) {
+ // Special case: 'rhs' is an integer that has the same width as a pointer and
+ // we are using the integer location in a comparison. Normally this cannot be
+ // triggered, but transfer functions like those for OSCommpareAndSwapBarrier32
+ // can generate comparisons that trigger this code.
+ // FIXME: Are all locations guaranteed to have pointer width?
+ if (BinaryOperator::isComparisonOp(op)) {
+ if (nonloc::ConcreteInt *rhsInt = dyn_cast<nonloc::ConcreteInt>(&rhs)) {
+ const llvm::APSInt *x = &rhsInt->getValue();
+ ASTContext &ctx = Context;
+ if (ctx.getTypeSize(ctx.VoidPtrTy) == x->getBitWidth()) {
+ // Convert the signedness of the integer (if necessary).
+ if (x->isSigned())
+ x = &getBasicValueFactory().getValue(*x, true);
+
+ return evalBinOpLL(state, op, lhs, loc::ConcreteInt(*x), resultTy);
+ }
+ }
+ }
+
+ // We are dealing with pointer arithmetic.
+
+ // Handle pointer arithmetic on constant values.
+ if (nonloc::ConcreteInt *rhsInt = dyn_cast<nonloc::ConcreteInt>(&rhs)) {
+ if (loc::ConcreteInt *lhsInt = dyn_cast<loc::ConcreteInt>(&lhs)) {
+ const llvm::APSInt &leftI = lhsInt->getValue();
+ assert(leftI.isUnsigned());
+ llvm::APSInt rightI(rhsInt->getValue(), /* isUnsigned */ true);
+
+ // Convert the bitwidth of rightI. This should deal with overflow
+ // since we are dealing with concrete values.
+ rightI = rightI.extOrTrunc(leftI.getBitWidth());
+
+ // Offset the increment by the pointer size.
+ llvm::APSInt Multiplicand(rightI.getBitWidth(), /* isUnsigned */ true);
+ rightI *= Multiplicand;
+
+ // Compute the adjusted pointer.
+ switch (op) {
+ case BO_Add:
+ rightI = leftI + rightI;
+ break;
+ case BO_Sub:
+ rightI = leftI - rightI;
+ break;
+ default:
+ llvm_unreachable("Invalid pointer arithmetic operation");
+ }
+ return loc::ConcreteInt(getBasicValueFactory().getValue(rightI));
+ }
+ }
+
+
+ // Delegate remaining pointer arithmetic to the StoreManager.
+ return state->getStateManager().getStoreManager().evalBinOp(op, lhs,
+ rhs, resultTy);
+}
+
+const llvm::APSInt *SimpleSValBuilder::getKnownValue(const GRState *state,
+ SVal V) {
+ if (V.isUnknownOrUndef())
+ return NULL;
+
+ if (loc::ConcreteInt* X = dyn_cast<loc::ConcreteInt>(&V))
+ return &X->getValue();
+
+ if (nonloc::ConcreteInt* X = dyn_cast<nonloc::ConcreteInt>(&V))
+ return &X->getValue();
+
+ if (SymbolRef Sym = V.getAsSymbol())
+ return state->getSymVal(Sym);
+
+ // FIXME: Add support for SymExprs.
+ return NULL;
+}