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// 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;
/// Tries to get the minimal possible (integer) value of a given SVal. This
/// always returns the value of a ConcreteInt, but may return NULL if the
/// value is symbolic and the constraint manager cannot provide a useful
/// answer.
virtual const llvm::APSInt *getMinValue(ProgramStateRef state, SVal val) = 0;
/// Tries to get the maximal possible (integer) value of a given SVal. This
/// always returns the value of a ConcreteInt, but may return NULL if the
/// value is symbolic and the constraint manager cannot provide a useful
/// answer.
virtual const llvm::APSInt *getMaxValue(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);
/// Create an SVal representing the result of an alloca()-like call, that is,
/// an AllocaRegion on the stack.
///
/// After calling this function, it's a good idea to set the extent of the
/// returned AllocaRegion.
loc::MemRegionVal getAllocaRegionVal(const Expr *E,
const LocationContext *LCtx,
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
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