1c1c1e25f9
Summary: By evaluating both children states, now we are capable of discovering infeasible parent states. In this patch, `assume` is implemented in the terms of `assumeDuali`. This might be suboptimal (e.g. where there are adjacent assume(true) and assume(false) calls, next patches addresses that). This patch fixes a real CRASH. Fixes https://github.com/llvm/llvm-project/issues/54272 Differential Revision: https://reviews.llvm.org/D124758
79 lines
3.1 KiB
C++
79 lines
3.1 KiB
C++
//===- ConstraintManager.cpp - Constraints on symbolic values. ------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defined the interface to manage constraints on symbolic values.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h"
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#include "clang/AST/Type.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
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using namespace clang;
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using namespace ento;
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ConstraintManager::~ConstraintManager() = default;
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static DefinedSVal getLocFromSymbol(const ProgramStateRef &State,
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SymbolRef Sym) {
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const MemRegion *R =
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State->getStateManager().getRegionManager().getSymbolicRegion(Sym);
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return loc::MemRegionVal(R);
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}
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ConditionTruthVal ConstraintManager::checkNull(ProgramStateRef State,
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SymbolRef Sym) {
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QualType Ty = Sym->getType();
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DefinedSVal V = Loc::isLocType(Ty) ? getLocFromSymbol(State, Sym)
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: nonloc::SymbolVal(Sym);
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const ProgramStatePair &P = assumeDual(State, V);
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if (P.first && !P.second)
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return ConditionTruthVal(false);
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if (!P.first && P.second)
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return ConditionTruthVal(true);
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return {};
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}
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ConstraintManager::ProgramStatePair
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ConstraintManager::assumeDual(ProgramStateRef State, DefinedSVal Cond) {
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ProgramStateRef StTrue = assumeInternal(State, Cond, true);
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if (!StTrue) {
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ProgramStateRef StFalse = assumeInternal(State, Cond, false);
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if (LLVM_UNLIKELY(!StFalse)) { // both infeasible
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ProgramStateRef StInfeasible = State->cloneAsPosteriorlyOverconstrained();
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assert(StInfeasible->isPosteriorlyOverconstrained());
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// Checkers might rely on the API contract that both returned states
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// cannot be null. Thus, we return StInfeasible for both branches because
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// it might happen that a Checker uncoditionally uses one of them if the
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// other is a nullptr. This may also happen with the non-dual and
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// adjacent `assume(true)` and `assume(false)` calls. By implementing
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// assume in therms of assumeDual, we can keep our API contract there as
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// well.
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return ProgramStatePair(StInfeasible, StInfeasible);
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}
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return ProgramStatePair(nullptr, StFalse);
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}
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ProgramStateRef StFalse = assumeInternal(State, Cond, false);
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if (!StFalse) {
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return ProgramStatePair(StTrue, nullptr);
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}
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return ProgramStatePair(StTrue, StFalse);
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}
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ProgramStateRef ConstraintManager::assume(ProgramStateRef State,
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DefinedSVal Cond, bool Assumption) {
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ConstraintManager::ProgramStatePair R = assumeDual(State, Cond);
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return Assumption ? R.first : R.second;
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}
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