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/SimpleConstraintManager.cpp b/lib/StaticAnalyzer/SimpleConstraintManager.cpp
new file mode 100644
index 0000000..e54d0ff
--- /dev/null
+++ b/lib/StaticAnalyzer/SimpleConstraintManager.cpp
@@ -0,0 +1,303 @@
+//== SimpleConstraintManager.cpp --------------------------------*- 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 SimpleConstraintManager, a class that holds code shared
+// between BasicConstraintManager and RangeConstraintManager.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SimpleConstraintManager.h"
+#include "clang/StaticAnalyzer/PathSensitive/ExprEngine.h"
+#include "clang/StaticAnalyzer/PathSensitive/GRState.h"
+#include "clang/StaticAnalyzer/PathSensitive/Checker.h"
+
+namespace clang {
+
+namespace ento {
+
+SimpleConstraintManager::~SimpleConstraintManager() {}
+
+bool SimpleConstraintManager::canReasonAbout(SVal X) const {
+ if (nonloc::SymExprVal *SymVal = dyn_cast<nonloc::SymExprVal>(&X)) {
+ const SymExpr *SE = SymVal->getSymbolicExpression();
+
+ if (isa<SymbolData>(SE))
+ return true;
+
+ 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;
+ }
+ }
+
+ return false;
+ }
+
+ return true;
+}
+
+const GRState *SimpleConstraintManager::assume(const GRState *state,
+ DefinedSVal Cond,
+ bool Assumption) {
+ if (isa<NonLoc>(Cond))
+ return assume(state, cast<NonLoc>(Cond), Assumption);
+ else
+ return assume(state, cast<Loc>(Cond), Assumption);
+}
+
+const GRState *SimpleConstraintManager::assume(const GRState *state, Loc cond,
+ bool assumption) {
+ state = assumeAux(state, cond, assumption);
+ return SU.ProcessAssume(state, cond, assumption);
+}
+
+const GRState *SimpleConstraintManager::assumeAux(const GRState *state,
+ Loc Cond, bool Assumption) {
+
+ BasicValueFactory &BasicVals = state->getBasicVals();
+
+ switch (Cond.getSubKind()) {
+ default:
+ assert (false && "'Assume' not implemented for this Loc.");
+ return state;
+
+ case loc::MemRegionKind: {
+ // FIXME: Should this go into the storemanager?
+
+ const MemRegion *R = cast<loc::MemRegionVal>(Cond).getRegion();
+ const SubRegion *SubR = dyn_cast<SubRegion>(R);
+
+ while (SubR) {
+ // FIXME: now we only find the first symbolic region.
+ if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SubR)) {
+ const llvm::APSInt &zero = BasicVals.getZeroWithPtrWidth();
+ if (Assumption)
+ return assumeSymNE(state, SymR->getSymbol(), zero, zero);
+ else
+ return assumeSymEQ(state, SymR->getSymbol(), zero, zero);
+ }
+ SubR = dyn_cast<SubRegion>(SubR->getSuperRegion());
+ }
+
+ // FALL-THROUGH.
+ }
+
+ case loc::GotoLabelKind:
+ return Assumption ? state : NULL;
+
+ case loc::ConcreteIntKind: {
+ bool b = cast<loc::ConcreteInt>(Cond).getValue() != 0;
+ bool isFeasible = b ? Assumption : !Assumption;
+ return isFeasible ? state : NULL;
+ }
+ } // end switch
+}
+
+const GRState *SimpleConstraintManager::assume(const GRState *state,
+ NonLoc cond,
+ bool assumption) {
+ state = assumeAux(state, cond, assumption);
+ return SU.ProcessAssume(state, cond, assumption);
+}
+
+static BinaryOperator::Opcode NegateComparison(BinaryOperator::Opcode op) {
+ // FIXME: This should probably be part of BinaryOperator, since this isn't
+ // the only place it's used. (This code was copied from SimpleSValBuilder.cpp.)
+ 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;
+ }
+}
+
+const GRState *SimpleConstraintManager::assumeAux(const GRState *state,
+ NonLoc Cond,
+ bool Assumption) {
+
+ // We cannot reason about SymSymExprs,
+ // and can only reason about some SymIntExprs.
+ if (!canReasonAbout(Cond)) {
+ // Just return the current state indicating that the path is feasible.
+ // This may be an over-approximation of what is possible.
+ return state;
+ }
+
+ BasicValueFactory &BasicVals = state->getBasicVals();
+ SymbolManager &SymMgr = state->getSymbolManager();
+
+ switch (Cond.getSubKind()) {
+ default:
+ assert(false && "'Assume' not implemented for this NonLoc");
+
+ case nonloc::SymbolValKind: {
+ nonloc::SymbolVal& SV = cast<nonloc::SymbolVal>(Cond);
+ SymbolRef sym = SV.getSymbol();
+ QualType T = SymMgr.getType(sym);
+ const llvm::APSInt &zero = BasicVals.getValue(0, T);
+ if (Assumption)
+ return assumeSymNE(state, sym, zero, zero);
+ else
+ return assumeSymEQ(state, sym, zero, zero);
+ }
+
+ case nonloc::SymExprValKind: {
+ nonloc::SymExprVal V = cast<nonloc::SymExprVal>(Cond);
+
+ // For now, we only handle expressions whose RHS is an integer.
+ // All other expressions are assumed to be feasible.
+ const SymIntExpr *SE = dyn_cast<SymIntExpr>(V.getSymbolicExpression());
+ if (!SE)
+ return state;
+
+ BinaryOperator::Opcode op = SE->getOpcode();
+ // Implicitly compare non-comparison expressions to 0.
+ if (!BinaryOperator::isComparisonOp(op)) {
+ QualType T = SymMgr.getType(SE);
+ const llvm::APSInt &zero = BasicVals.getValue(0, T);
+ op = (Assumption ? BO_NE : BO_EQ);
+ return assumeSymRel(state, SE, op, zero);
+ }
+
+ // From here on out, op is the real comparison we'll be testing.
+ if (!Assumption)
+ op = NegateComparison(op);
+
+ return assumeSymRel(state, SE->getLHS(), op, SE->getRHS());
+ }
+
+ case nonloc::ConcreteIntKind: {
+ bool b = cast<nonloc::ConcreteInt>(Cond).getValue() != 0;
+ bool isFeasible = b ? Assumption : !Assumption;
+ return isFeasible ? state : NULL;
+ }
+
+ case nonloc::LocAsIntegerKind:
+ return assumeAux(state, cast<nonloc::LocAsInteger>(Cond).getLoc(),
+ Assumption);
+ } // end switch
+}
+
+const GRState *SimpleConstraintManager::assumeSymRel(const GRState *state,
+ const SymExpr *LHS,
+ BinaryOperator::Opcode op,
+ const llvm::APSInt& Int) {
+ assert(BinaryOperator::isComparisonOp(op) &&
+ "Non-comparison ops should be rewritten as comparisons to zero.");
+
+ // We only handle simple comparisons of the form "$sym == constant"
+ // or "($sym+constant1) == constant2".
+ // The adjustment is "constant1" in the above expression. It's used to
+ // "slide" the solution range around for modular arithmetic. For example,
+ // x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
+ // in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
+ // the subclasses of SimpleConstraintManager to handle the adjustment.
+ llvm::APSInt Adjustment;
+
+ // First check if the LHS is a simple symbol reference.
+ SymbolRef Sym = dyn_cast<SymbolData>(LHS);
+ if (Sym) {
+ Adjustment = 0;
+ } else {
+ // Next, see if it's a "($sym+constant1)" expression.
+ const SymIntExpr *SE = dyn_cast<SymIntExpr>(LHS);
+
+ // We don't handle "($sym1+$sym2)".
+ // Give up and assume the constraint is feasible.
+ if (!SE)
+ return state;
+
+ // We don't handle "(<expr>+constant1)".
+ // Give up and assume the constraint is feasible.
+ Sym = dyn_cast<SymbolData>(SE->getLHS());
+ if (!Sym)
+ return state;
+
+ // Get the constant out of the expression "($sym+constant1)".
+ switch (SE->getOpcode()) {
+ case BO_Add:
+ Adjustment = SE->getRHS();
+ break;
+ case BO_Sub:
+ Adjustment = -SE->getRHS();
+ break;
+ default:
+ // We don't handle non-additive operators.
+ // Give up and assume the constraint is feasible.
+ return state;
+ }
+ }
+
+ // FIXME: This next section is a hack. It silently converts the integers to
+ // be of the same type as the symbol, which is not always correct. Really the
+ // comparisons should be performed using the Int's type, then mapped back to
+ // the symbol's range of values.
+ GRStateManager &StateMgr = state->getStateManager();
+ ASTContext &Ctx = StateMgr.getContext();
+
+ QualType T = Sym->getType(Ctx);
+ assert(T->isIntegerType() || Loc::IsLocType(T));
+ unsigned bitwidth = Ctx.getTypeSize(T);
+ bool isSymUnsigned = T->isUnsignedIntegerType() || Loc::IsLocType(T);
+
+ // Convert the adjustment.
+ Adjustment.setIsUnsigned(isSymUnsigned);
+ Adjustment = Adjustment.extOrTrunc(bitwidth);
+
+ // Convert the right-hand side integer.
+ llvm::APSInt ConvertedInt(Int, isSymUnsigned);
+ ConvertedInt = ConvertedInt.extOrTrunc(bitwidth);
+
+ switch (op) {
+ default:
+ // No logic yet for other operators. assume the constraint is feasible.
+ return state;
+
+ case BO_EQ:
+ return assumeSymEQ(state, Sym, ConvertedInt, Adjustment);
+
+ case BO_NE:
+ return assumeSymNE(state, Sym, ConvertedInt, Adjustment);
+
+ case BO_GT:
+ return assumeSymGT(state, Sym, ConvertedInt, Adjustment);
+
+ case BO_GE:
+ return assumeSymGE(state, Sym, ConvertedInt, Adjustment);
+
+ case BO_LT:
+ return assumeSymLT(state, Sym, ConvertedInt, Adjustment);
+
+ case BO_LE:
+ return assumeSymLE(state, Sym, ConvertedInt, Adjustment);
+ } // end switch
+}
+
+} // end of namespace ento
+
+} // end of namespace clang