llvm/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp

// SimpleSValBuilder.cpp - A basic SValBuilder -----------------------*- 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 SimpleSValBuilder, a basic implementation of SValBuilder.
//
//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SValVisitor.h"
#include <optional>

usingnamespaceclang;
usingnamespaceento;

namespace {
class SimpleSValBuilder : public SValBuilder { … };
} // end anonymous namespace

SValBuilder *ento::createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
                                           ASTContext &context,
                                           ProgramStateManager &stateMgr) { … }

// Checks if the negation the value and flipping sign preserve
// the semantics on the operation in the resultType
static bool isNegationValuePreserving(const llvm::APSInt &Value,
                                      APSIntType ResultType) { … }

//===----------------------------------------------------------------------===//
// Transfer function for binary operators.
//===----------------------------------------------------------------------===//

SVal SimpleSValBuilder::MakeSymIntVal(const SymExpr *LHS,
                                    BinaryOperator::Opcode op,
                                    const llvm::APSInt &RHS,
                                    QualType resultTy) { … }

// See if Sym is known to be a relation Rel with Bound.
static bool isInRelation(BinaryOperator::Opcode Rel, SymbolRef Sym,
                         llvm::APSInt Bound, ProgramStateRef State) { … }

// See if Sym is known to be within [min/4, max/4], where min and max
// are the bounds of the symbol's integral type. With such symbols,
// some manipulations can be performed without the risk of overflow.
// assume() doesn't cause infinite recursion because we should be dealing
// with simpler symbols on every recursive call.
static bool isWithinConstantOverflowBounds(SymbolRef Sym,
                                           ProgramStateRef State) { … }

// Same for the concrete integers: see if I is within [min/4, max/4].
static bool isWithinConstantOverflowBounds(llvm::APSInt I) { … }

static std::pair<SymbolRef, llvm::APSInt>
decomposeSymbol(SymbolRef Sym, BasicValueFactory &BV) { … }

// Simplify "(LSym + LInt) Op (RSym + RInt)" assuming all values are of the
// same signed integral type and no overflows occur (which should be checked
// by the caller).
static NonLoc doRearrangeUnchecked(ProgramStateRef State,
                                   BinaryOperator::Opcode Op,
                                   SymbolRef LSym, llvm::APSInt LInt,
                                   SymbolRef RSym, llvm::APSInt RInt) { … }

// Rearrange if symbol type matches the result type and if the operator is a
// comparison operator, both symbol and constant must be within constant
// overflow bounds.
static bool shouldRearrange(ProgramStateRef State, BinaryOperator::Opcode Op,
                            SymbolRef Sym, llvm::APSInt Int, QualType Ty) { … }

static std::optional<NonLoc> tryRearrange(ProgramStateRef State,
                                          BinaryOperator::Opcode Op, NonLoc Lhs,
                                          NonLoc Rhs, QualType ResultTy) { … }

SVal SimpleSValBuilder::evalBinOpNN(ProgramStateRef state,
                                  BinaryOperator::Opcode op,
                                  NonLoc lhs, NonLoc rhs,
                                  QualType resultTy)  { … }

static SVal evalBinOpFieldRegionFieldRegion(const FieldRegion *LeftFR,
                                            const FieldRegion *RightFR,
                                            BinaryOperator::Opcode op,
                                            QualType resultTy,
                                            SimpleSValBuilder &SVB) { … }

// This is used in debug builds only for now because some downstream users
// may hit this assert in their subsequent merges.
// There are still places in the analyzer where equal bitwidth Locs
// are compared, and need to be found and corrected. Recent previous fixes have
// addressed the known problems of making NULLs with specific bitwidths
// for Loc comparisons along with deprecation of APIs for the same purpose.
//
static void assertEqualBitWidths(ProgramStateRef State, Loc RhsLoc,
                                 Loc LhsLoc) { … }

// FIXME: all this logic will change if/when we have MemRegion::getLocation().
SVal SimpleSValBuilder::evalBinOpLL(ProgramStateRef state,
                                  BinaryOperator::Opcode op,
                                  Loc lhs, Loc rhs,
                                  QualType resultTy) { … }

SVal SimpleSValBuilder::evalBinOpLN(ProgramStateRef state,
                                    BinaryOperator::Opcode op, Loc lhs,
                                    NonLoc rhs, QualType resultTy) { … }

const llvm::APSInt *SimpleSValBuilder::getConstValue(ProgramStateRef state,
                                                     SVal V) { … }

const llvm::APSInt *SimpleSValBuilder::getConcreteValue(SVal V) { … }

const llvm::APSInt *SimpleSValBuilder::getKnownValue(ProgramStateRef state,
                                                     SVal V) { … }

const llvm::APSInt *SimpleSValBuilder::getMinValue(ProgramStateRef state,
                                                   SVal V) { … }

const llvm::APSInt *SimpleSValBuilder::getMaxValue(ProgramStateRef state,
                                                   SVal V) { … }

SVal SimpleSValBuilder::simplifyUntilFixpoint(ProgramStateRef State, SVal Val) { … }

SVal SimpleSValBuilder::simplifySVal(ProgramStateRef State, SVal V) { … }

SVal SimpleSValBuilder::simplifySValOnce(ProgramStateRef State, SVal V) { … }