Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

// SValBuilder.h - Construction of SVals from evaluating expressions -*- 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 SValBuilder, a class that defines the interface for

//  "symbolical evaluators" which construct an SVal from an expression.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H

#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H

#include "clang/AST/ASTContext.h"

#include "clang/AST/DeclarationName.h"

#include "clang/AST/Expr.h"

#include "clang/AST/ExprObjC.h"

#include "clang/AST/Type.h"

#include "clang/Basic/LLVM.h"

#include "clang/Basic/LangOptions.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"

#include "llvm/ADT/ImmutableList.h"

#include <cstdint>

#include <optional>

namespace clang {

class AnalyzerOptions;

class BlockDecl;

class CXXBoolLiteralExpr;

class CXXMethodDecl;

class CXXRecordDecl;

class DeclaratorDecl;

class FunctionDecl;

class LocationContext;

class StackFrameContext;

class Stmt;

namespace ento {

class ConditionTruthVal;

class ProgramStateManager;

class StoreRef;

class SValBuilder {

  virtual void anchor();

protected:

  ASTContext &Context;

  /// Manager of APSInt values.

  BasicValueFactory BasicVals;

  /// Manages the creation of symbols.

  SymbolManager SymMgr;

  /// Manages the creation of memory regions.

  MemRegionManager MemMgr;

  ProgramStateManager &StateMgr;

  const AnalyzerOptions &AnOpts;

  /// The scalar type to use for array indices.

  const QualType ArrayIndexTy;

  /// The width of the scalar type used for array indices.

  const unsigned ArrayIndexWidth;

public:

  SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,

              ProgramStateManager &stateMgr);

  virtual ~SValBuilder() = default;

  SVal evalCast(SVal V, QualType CastTy, QualType OriginalTy);

  // Handles casts of type CK_IntegralCast.

  SVal evalIntegralCast(ProgramStateRef state, SVal val, QualType castTy,

                        QualType originalType);

  SVal evalMinus(NonLoc val);

  SVal evalComplement(NonLoc val);

  /// Create a new value which represents a binary expression with two non-

  /// location operands.

  virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op,

                           NonLoc lhs, NonLoc rhs, QualType resultTy) = 0;

  /// Create a new value which represents a binary expression with two memory

  /// location operands.

  virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op,

                           Loc lhs, Loc rhs, QualType resultTy) = 0;

  /// Create a new value which represents a binary expression with a memory

  /// location and non-location operands. For example, this would be used to

  /// evaluate a pointer arithmetic operation.

  virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op,

                           Loc lhs, NonLoc rhs, QualType resultTy) = 0;

  /// 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(ProgramStateRef state, SVal val) = 0;

  /// Simplify symbolic expressions within a given SVal. Return an SVal

  /// that represents the same value, but is hopefully easier to work with

  /// than the original SVal.

  virtual SVal simplifySVal(ProgramStateRef State, SVal Val) = 0;

  /// Constructs a symbolic expression for two non-location values.

  SVal makeSymExprValNN(BinaryOperator::Opcode op,

                        NonLoc lhs, NonLoc rhs, QualType resultTy);

  SVal evalUnaryOp(ProgramStateRef state, UnaryOperator::Opcode opc,

                 SVal operand, QualType type);

  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,

                 SVal lhs, SVal rhs, QualType type);

  /// \return Whether values in \p lhs and \p rhs are equal at \p state.

  ConditionTruthVal areEqual(ProgramStateRef state, SVal lhs, SVal rhs);

  SVal evalEQ(ProgramStateRef state, SVal lhs, SVal rhs);

  DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs,

                              DefinedOrUnknownSVal rhs);

  ASTContext &getContext() { return Context; }

  const ASTContext &getContext() const { return Context; }

  ProgramStateManager &getStateManager() { return StateMgr; }

  QualType getConditionType() const {

    return Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.IntTy;

  }

  QualType getArrayIndexType() const {

    return ArrayIndexTy;

  }

  BasicValueFactory &getBasicValueFactory() { return BasicVals; }

  const BasicValueFactory &getBasicValueFactory() const { return BasicVals; }

  SymbolManager &getSymbolManager() { return SymMgr; }

  const SymbolManager &getSymbolManager() const { return SymMgr; }

  MemRegionManager &getRegionManager() { return MemMgr; }

  const MemRegionManager &getRegionManager() const { return MemMgr; }

  const AnalyzerOptions &getAnalyzerOptions() const { return AnOpts; }

  // Forwarding methods to SymbolManager.

  const SymbolConjured* conjureSymbol(const Stmt *stmt,

                                      const LocationContext *LCtx,

                                      QualType type,

                                      unsigned visitCount,

                                      const void *symbolTag = nullptr) {

    return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag);

  }

  const SymbolConjured* conjureSymbol(const Expr *expr,

                                      const LocationContext *LCtx,

                                      unsigned visitCount,

                                      const void *symbolTag = nullptr) {

    return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag);

  }

  /// Construct an SVal representing '0' for the specified type.

  DefinedOrUnknownSVal makeZeroVal(QualType type);

  /// Make a unique symbol for value of region.

  DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region);

  /// Create a new symbol with a unique 'name'.

  ///

  /// We resort to conjured symbols when we cannot construct a derived symbol.

  /// The advantage of symbols derived/built from other symbols is that we

  /// preserve the relation between related(or even equivalent) expressions, so

  /// conjured symbols should be used sparingly.

  DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag,

                                        const Expr *expr,

                                        const LocationContext *LCtx,

                                        unsigned count);

  DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag,

                                        const Expr *expr,

                                        const LocationContext *LCtx,

                                        QualType type,

                                        unsigned count);

  DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt,

                                        const LocationContext *LCtx,

                                        QualType type,

                                        unsigned visitCount);

  /// Conjure a symbol representing heap allocated memory region.

  ///

  /// Note, the expression should represent a location.

  DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E,

                                                const LocationContext *LCtx,

                                                unsigned Count);

  /// Conjure a symbol representing heap allocated memory region.

  ///

  /// Note, now, the expression *doesn't* need to represent a location.

  /// But the type need to!

  DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E,

                                                const LocationContext *LCtx,

                                                QualType type, unsigned Count);

  DefinedOrUnknownSVal getDerivedRegionValueSymbolVal(

      SymbolRef parentSymbol, const TypedValueRegion *region);

  DefinedSVal getMetadataSymbolVal(const void *symbolTag,

                                   const MemRegion *region,

                                   const Expr *expr, QualType type,

                                   const LocationContext *LCtx,

                                   unsigned count);

  DefinedSVal getMemberPointer(const NamedDecl *ND);

  DefinedSVal getFunctionPointer(const FunctionDecl *func);

  DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy,

                              const LocationContext *locContext,

                              unsigned blockCount);

  /// Returns the value of \p E, if it can be determined in a non-path-sensitive

  /// manner.

  ///

  /// If \p E is not a constant or cannot be modeled, returns \c std::nullopt.

  std::optional<SVal> getConstantVal(const Expr *E);

  NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) {

    return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals));

  }

  NonLoc makeLazyCompoundVal(const StoreRef &store,

                             const TypedValueRegion *region) {

    return nonloc::LazyCompoundVal(

        BasicVals.getLazyCompoundValData(store, region));

  }

  NonLoc makePointerToMember(const DeclaratorDecl *DD) {

    return nonloc::PointerToMember(DD);

  }

  NonLoc makePointerToMember(const PointerToMemberData *PTMD) {

    return nonloc::PointerToMember(PTMD);

  }

  NonLoc makeZeroArrayIndex() {

    return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy));

  }

  NonLoc makeArrayIndex(uint64_t idx) {

    return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy));

  }

  SVal convertToArrayIndex(SVal val);

  nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) {

    return nonloc::ConcreteInt(

        BasicVals.getValue(integer->getValue(),

                     integer->getType()->isUnsignedIntegerOrEnumerationType()));

  }

  nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) {

    return makeTruthVal(boolean->getValue(), boolean->getType());

  }

  nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean);

  nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) {

    return nonloc::ConcreteInt(BasicVals.getValue(integer));

  }

  loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) {

    return loc::ConcreteInt(BasicVals.getValue(integer));

  }

  NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) {

    return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned));

  }

  DefinedSVal makeIntVal(uint64_t integer, QualType type) {

    if (Loc::isLocType(type))

      return loc::ConcreteInt(BasicVals.getValue(integer, type));

    return nonloc::ConcreteInt(BasicVals.getValue(integer, type));

  }

  NonLoc makeIntVal(uint64_t integer, bool isUnsigned) {

    return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned));

  }

  NonLoc makeIntValWithWidth(QualType ptrType, uint64_t integer) {

    return nonloc::ConcreteInt(BasicVals.getValue(integer, ptrType));

  }

  NonLoc makeLocAsInteger(Loc loc, unsigned bits) {

    return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits));

  }

  nonloc::SymbolVal makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,

                               const llvm::APSInt &rhs, QualType type);

  nonloc::SymbolVal makeNonLoc(const llvm::APSInt &rhs,

                               BinaryOperator::Opcode op, const SymExpr *lhs,

                               QualType type);

  nonloc::SymbolVal makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,

                               const SymExpr *rhs, QualType type);

  NonLoc makeNonLoc(const SymExpr *operand, UnaryOperator::Opcode op,

                    QualType type);

  /// Create a NonLoc value for cast.

  nonloc::SymbolVal makeNonLoc(const SymExpr *operand, QualType fromTy,

                               QualType toTy);

  nonloc::ConcreteInt makeTruthVal(bool b, QualType type) {

    return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type));

  }

  nonloc::ConcreteInt makeTruthVal(bool b) {

    return nonloc::ConcreteInt(BasicVals.getTruthValue(b));

  }

  /// Create NULL pointer, with proper pointer bit-width for given address

  /// space.

  /// \param type pointer type.

  loc::ConcreteInt makeNullWithType(QualType type) {

    // We cannot use the `isAnyPointerType()`.

    assert((type->isPointerType() || type->isObjCObjectPointerType() ||

            type->isBlockPointerType() || type->isNullPtrType() ||

            type->isReferenceType()) &&

           "makeNullWithType must use pointer type");

    // The `sizeof(T&)` is `sizeof(T)`, thus we replace the reference with a

    // pointer. Here we assume that references are actually implemented by

    // pointers under-the-hood.

    type = type->isReferenceType()

               ? Context.getPointerType(type->getPointeeType())

               : type;

    return loc::ConcreteInt(BasicVals.getZeroWithTypeSize(type));

  }

  loc::MemRegionVal makeLoc(SymbolRef sym) {

    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));

  }

  loc::MemRegionVal makeLoc(const MemRegion *region) {

    return loc::MemRegionVal(region);

  }

  loc::GotoLabel makeLoc(const AddrLabelExpr *expr) {

    return loc::GotoLabel(expr->getLabel());

  }

  loc::ConcreteInt makeLoc(const llvm::APSInt &integer) {

    return loc::ConcreteInt(BasicVals.getValue(integer));

  }

  /// Return MemRegionVal on success cast, otherwise return std::nullopt.

  std::optional<loc::MemRegionVal>

  getCastedMemRegionVal(const MemRegion *region, QualType type);

  /// Make an SVal that represents the given symbol. This follows the convention

  /// of representing Loc-type symbols (symbolic pointers and references)

  /// as Loc values wrapping the symbol rather than as plain symbol values.

  DefinedSVal makeSymbolVal(SymbolRef Sym) {

    if (Loc::isLocType(Sym->getType()))

      return makeLoc(Sym);

    return nonloc::SymbolVal(Sym);

  }

  /// Return a memory region for the 'this' object reference.

  loc::MemRegionVal getCXXThis(const CXXMethodDecl *D,

                               const StackFrameContext *SFC);

  /// Return a memory region for the 'this' object reference.

  loc::MemRegionVal getCXXThis(const CXXRecordDecl *D,

                               const StackFrameContext *SFC);

};

SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,

                                     ASTContext &context,

                                     ProgramStateManager &stateMgr);

} // namespace ento

} // namespace clang

#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H