Holds the state of the program (store and heap) at a given program point. More...

#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"

Classes
class	ValueModel
	Supplements `Environment` with non-standard comparison and join operations. More...

Public Types
enum	ExprJoinBehavior { DiscardExprState , KeepExprState }
	How to treat expression state (`ExprToLoc` and `ExprToVal`) in a join. More...

Public Member Functions
	Environment (DataflowAnalysisContext &DACtx)
	Creates an environment that uses `DACtx` to store objects that encompass the state of a program.

	Environment (DataflowAnalysisContext &DACtx, Stmt &S)
	Creates an environment that uses `DACtx` to store objects that encompass the state of a program, with `S` as the statement to analyze.

	Environment (DataflowAnalysisContext &DACtx, const FunctionDecl &FD)
	Creates an environment that uses `DACtx` to store objects that encompass the state of a program, with `FD` as the function to analyze.

Environment &	operator= (const Environment &Other)=delete

	Environment (Environment &&Other)=default

Environment &	operator= (Environment &&Other)=default

void	initialize ()
	Assigns storage locations and values to all parameters, captures, global variables, fields and functions referenced in the `Stmt` or `FunctionDecl` passed to the constructor.

Environment	fork () const
	Returns a new environment that is a copy of this one.

Environment	pushCall (const CallExpr *Call) const
	Creates and returns an environment to use for an inline analysis of the callee.

Environment	pushCall (const CXXConstructExpr *Call) const

void	popCall (const CallExpr *Call, const Environment &CalleeEnv)
	Moves gathered information back into `this` from a `CalleeEnv` created via `pushCall`.

void	popCall (const CXXConstructExpr *Call, const Environment &CalleeEnv)

bool	equivalentTo (const Environment &Other, Environment::ValueModel &Model) const
	Returns true if and only if the environment is equivalent to `Other`, i.e the two environments:

LatticeEffect	widen (const Environment &PrevEnv, Environment::ValueModel &Model)
	Widens the environment point-wise, using `PrevEnv` as needed to inform the approximation.

StorageLocation &	createStorageLocation (QualType Type)
	Creates a storage location appropriate for `Type`.

StorageLocation &	createStorageLocation (const ValueDecl &D)
	Creates a storage location for `D`.

StorageLocation &	createStorageLocation (const Expr &E)
	Creates a storage location for `E`.

void	setStorageLocation (const ValueDecl &D, StorageLocation &Loc)
	Assigns `Loc` as the storage location of `D` in the environment.

StorageLocation *	getStorageLocation (const ValueDecl &D) const
	Returns the storage location assigned to `D` in the environment, or null if `D` isn't assigned a storage location in the environment.

void	removeDecl (const ValueDecl &D)
	Removes the location assigned to `D` in the environment (if any).

void	setStorageLocation (const Expr &E, StorageLocation &Loc)
	Assigns `Loc` as the storage location of the glvalue `E` in the environment.

StorageLocation *	getStorageLocation (const Expr &E) const
	Returns the storage location assigned to the glvalue `E` in the environment, or null if `E` isn't assigned a storage location in the environment.

template<typename T >
std::enable_if_t< std::is_base_of_v< StorageLocation, T >, T * >	get (const ValueDecl &D) const
	Returns the result of casting `getStorageLocation(...)` to a subclass of `StorageLocation` (using `cast_or_null<T>`).

template<typename T >
std::enable_if_t< std::is_base_of_v< StorageLocation, T >, T * >	get (const Expr &E) const

RecordStorageLocation *	getThisPointeeStorageLocation () const
	Returns the storage location assigned to the `this` pointee in the environment or null if the `this` pointee has no assigned storage location in the environment.

void	setThisPointeeStorageLocation (RecordStorageLocation &Loc)
	Sets the storage location assigned to the `this` pointee in the environment.

RecordStorageLocation &	getResultObjectLocation (const Expr &RecordPRValue) const
	Returns the location of the result object for a record-type prvalue.

Value *	getReturnValue () const
	Returns the return value of the function currently being analyzed.

StorageLocation *	getReturnStorageLocation () const
	Returns the storage location for the reference returned by the function currently being analyzed.

void	setReturnValue (Value *Val)
	Sets the return value of the function currently being analyzed.

void	setReturnStorageLocation (StorageLocation *Loc)
	Sets the storage location for the reference returned by the function currently being analyzed.

PointerValue &	getOrCreateNullPointerValue (QualType PointeeType)
	Returns a pointer value that represents a null pointer.

Value *	createValue (QualType Type)
	Creates a value appropriate for `Type`, if `Type` is supported, otherwise returns null.

StorageLocation &	createObject (QualType Ty, const Expr *InitExpr=nullptr)
	Creates an object (i.e.

StorageLocation &	createObject (const VarDecl &D)
	Creates an object for the variable declaration `D`.

StorageLocation &	createObject (const ValueDecl &D, const Expr *InitExpr)
	Creates an object for the variable declaration `D`.

void	initializeFieldsWithValues (RecordStorageLocation &Loc, QualType Type)
	Initializes the fields (including synthetic fields) of `Loc` with values, unless values of the field type are not supported or we hit one of the limits at which we stop producing values.

void	initializeFieldsWithValues (RecordStorageLocation &Loc)

void	setValue (const StorageLocation &Loc, Value &Val)
	Assigns `Val` as the value of `Loc` in the environment.

void	clearValue (const StorageLocation &Loc)
	Clears any association between `Loc` and a value in the environment.

void	setValue (const Expr &E, Value &Val)
	Assigns `Val` as the value of the prvalue `E` in the environment.

Value *	getValue (const StorageLocation &Loc) const
	Returns the value assigned to `Loc` in the environment or null if `Loc` isn't assigned a value in the environment.

Value *	getValue (const ValueDecl &D) const
	Equivalent to `getValue(getStorageLocation(D))` if `D` is assigned a storage location in the environment, otherwise returns null.

Value *	getValue (const Expr &E) const
	Equivalent to `getValue(getStorageLocation(E, SP))` if `E` is assigned a storage location in the environment, otherwise returns null.

template<typename T >
std::enable_if_t< std::is_base_of_v< Value, T >, T * >	get (const StorageLocation &Loc) const
	Returns the result of casting `getValue(...)` to a subclass of `Value` (using `cast_or_null<T>`).

template<typename T >
std::enable_if_t< std::is_base_of_v< Value, T >, T * >	get (const ValueDecl &D) const

template<typename T >
std::enable_if_t< std::is_base_of_v< Value, T >, T * >	get (const Expr &E) const

template<typename T , typename... Args>
std::enable_if_t< std::is_base_of< Value, T >::value, T & >	create (Args &&...args)
	Creates a `T` (some subclass of `Value`), forwarding `args` to the constructor, and returns a reference to it.

IntegerValue &	getIntLiteralValue (llvm::APInt Value) const
	Returns a symbolic integer value that models an integer literal equal to `Value`

BoolValue &	getBoolLiteralValue (bool Value) const
	Returns a symbolic boolean value that models a boolean literal equal to `Value`

BoolValue &	makeAtomicBoolValue () const
	Returns an atomic boolean value.

BoolValue &	makeTopBoolValue () const
	Returns a unique instance of boolean Top.

BoolValue &	makeAnd (BoolValue &LHS, BoolValue &RHS) const
	Returns a boolean value that represents the conjunction of `LHS` and `RHS`.

BoolValue &	makeOr (BoolValue &LHS, BoolValue &RHS) const
	Returns a boolean value that represents the disjunction of `LHS` and `RHS`.

BoolValue &	makeNot (BoolValue &Val) const
	Returns a boolean value that represents the negation of `Val`.

BoolValue &	makeImplication (BoolValue &LHS, BoolValue &RHS) const
	Returns a boolean value represents `LHS` => `RHS`.

BoolValue &	makeIff (BoolValue &LHS, BoolValue &RHS) const
	Returns a boolean value represents `LHS` <=> `RHS`.

Atom	getFlowConditionToken () const
	Returns a boolean variable that identifies the flow condition (FC).

void	assume (const Formula &)
	Record a fact that must be true if this point in the program is reached.

bool	proves (const Formula &) const
	Returns true if the formula is always true when this point is reached.

bool	allows (const Formula &) const
	Returns true if the formula may be true when this point is reached.

const FunctionDecl *	getCurrentFunc () const
	Returns the function currently being analyzed, or null if the code being analyzed isn't part of a function.

size_t	callStackSize () const
	Returns the size of the call stack, not counting the initial analysis target.

bool	canDescend (unsigned MaxDepth, const FunctionDecl *Callee) const
	Returns whether this `Environment` can be extended to analyze the given `Callee` (i.e.

DataflowAnalysisContext &	getDataflowAnalysisContext () const
	Returns the `DataflowAnalysisContext` used by the environment.

Arena &	arena () const

LLVM_DUMP_METHOD void	dump () const

LLVM_DUMP_METHOD void	dump (raw_ostream &OS) const

Static Public Member Functions
static Environment	join (const Environment &EnvA, const Environment &EnvB, Environment::ValueModel &Model, ExprJoinBehavior ExprBehavior)
	Joins two environments by taking the intersection of storage locations and values that are stored in them.

static Value *	joinValues (QualType Ty, Value Val1, const Environment &Env1, Value Val2, const Environment &Env2, Environment &JoinedEnv, Environment::ValueModel &Model)
	Returns a value that approximates both `Val1` and `Val2`, or null if no such value can be produced.

Detailed Description

Holds the state of the program (store and heap) at a given program point.

WARNING: Symbolic values that are created by the environment for static local and global variables are not currently invalidated on function calls. This is unsound and should be taken into account when designing dataflow analyses.

Definition at line 65 of file DataflowEnvironment.h.

Member Enumeration Documentation

◆ ExprJoinBehavior

enum clang::dataflow::Environment::ExprJoinBehavior

How to treat expression state (ExprToLoc and ExprToVal) in a join.

If the join happens within a full expression, expression state should be kept; otherwise, we can discard it.

Enumerator
DiscardExprState
KeepExprState

Definition at line 242 of file DataflowEnvironment.h.

Constructor & Destructor Documentation

◆ Environment() [1/4]

clang::dataflow::Environment::Environment ( DataflowAnalysisContext & DACtx )

inlineexplicit

Creates an environment that uses DACtx to store objects that encompass the state of a program.

Definition at line 161 of file DataflowEnvironment.h.

◆ Environment() [2/4]

clang::dataflow::Environment::Environment	(	DataflowAnalysisContext &	DACtx,
		Stmt &	S
	)

inline

Creates an environment that uses DACtx to store objects that encompass the state of a program, with S as the statement to analyze.

Definition at line 167 of file DataflowEnvironment.h.

◆ Environment() [3/4]

clang::dataflow::Environment::Environment	(	DataflowAnalysisContext &	DACtx,
		const FunctionDecl &	FD
	)

inline

Creates an environment that uses DACtx to store objects that encompass the state of a program, with FD as the function to analyze.

Requirements:

The function must have a body, i.e. FunctionDecl::doesThisDecalarationHaveABody() must be true.

Definition at line 178 of file DataflowEnvironment.h.

References clang::FunctionDecl::doesThisDeclarationHaveABody().

◆ Environment() [4/4]

clang::dataflow::Environment::Environment ( Environment && Other )

default

Member Function Documentation

◆ allows()

bool clang::dataflow::Environment::allows ( const Formula & F ) const

Returns true if the formula may be true when this point is reached.

Returns false if the formula is always false when this point is reached (or the flow condition is overly constraining) or if the solver times out.

Definition at line 1146 of file DataflowEnvironment.cpp.

References clang::dataflow::DataflowAnalysisContext::flowConditionAllows().

◆ arena()

Arena & clang::dataflow::Environment::arena ( ) const

inline

Definition at line 679 of file DataflowEnvironment.h.

References clang::dataflow::DataflowAnalysisContext::arena().

Referenced by create(), getBoolLiteralValue(), getIntLiteralValue(), clang::dataflow::joinDistinctValues(), makeAnd(), makeAtomicBoolValue(), makeIff(), makeImplication(), makeNot(), makeOr(), makeTopBoolValue(), and clang::dataflow::widenDistinctValues().

◆ assume()

void clang::dataflow::Environment::assume ( const Formula & F )

Record a fact that must be true if this point in the program is reached.

Definition at line 1138 of file DataflowEnvironment.cpp.

References clang::dataflow::DataflowAnalysisContext::addFlowConditionConstraint().

Referenced by clang::dataflow::joinDistinctValues().

◆ callStackSize()

size_t clang::dataflow::Environment::callStackSize ( ) const

inline

Returns the size of the call stack, not counting the initial analysis target.

Definition at line 668 of file DataflowEnvironment.h.

◆ canDescend()

bool clang::dataflow::Environment::canDescend	(	unsigned	MaxDepth,
		const FunctionDecl *	Callee
	)		const

Returns whether this Environment can be extended to analyze the given Callee (i.e.

if pushCall can be used). Recursion is not allowed. MaxDepth is the maximum size of the call stack (i.e. the maximum value that callStackSize() may assume after the call).

Definition at line 601 of file DataflowEnvironment.cpp.

◆ clearValue()

void clang::dataflow::Environment::clearValue ( const StorageLocation & Loc )

inline

Clears any association between Loc and a value in the environment.

Definition at line 498 of file DataflowEnvironment.h.

References Loc.

Referenced by clang::dataflow::copyField(), and clang::dataflow::copySyntheticField().

◆ create()

template<typename T , typename... Args>

std::enable_if_t< std::is_base_of< Value, T >::value, T & > clang::dataflow::Environment::create ( Args &&... args )

inline

Creates a T (some subclass of Value), forwarding args to the constructor, and returns a reference to it.

The analysis context takes ownership of the created object. The object will be destroyed when the analysis context is destroyed.

Definition at line 557 of file DataflowEnvironment.h.

References arena(), clang::dataflow::Arena::create(), and clang::T.

◆ createObject() [1/3]

StorageLocation & clang::dataflow::Environment::createObject	(	const ValueDecl &	D,
		const Expr *	InitExpr
	)

inline

Creates an object for the variable declaration D.

If InitExpr is non-null and has a value associated with it, initializes the object with this value. Otherwise, initializes the object with a value created using createValue(). Uses the storage location returned by DataflowAnalysisContext::getStableStorageLocation(D).

Definition at line 474 of file DataflowEnvironment.h.

References D.

◆ createObject() [2/3]

StorageLocation & clang::dataflow::Environment::createObject ( const VarDecl & D )

inline

Creates an object for the variable declaration D.

If D has an initializer and this initializer is associated with a value, initializes the object with this value. Otherwise, initializes the object with a value created using createValue(). Uses the storage location returned by DataflowAnalysisContext::getStableStorageLocation(D).

Definition at line 465 of file DataflowEnvironment.h.

References D.

◆ createObject() [3/3]

StorageLocation & clang::dataflow::Environment::createObject	(	QualType	Ty,
		const Expr *	InitExpr = `nullptr`
	)

inline

Creates an object (i.e.

a storage location with an associated value) of type Ty. If InitExpr is non-null and has a value associated with it, initializes the object with this value. Otherwise, initializes the object with a value created using createValue().

Definition at line 456 of file DataflowEnvironment.h.

Referenced by initialize().

◆ createStorageLocation() [1/3]

StorageLocation & clang::dataflow::Environment::createStorageLocation ( const Expr & E )

Creates a storage location for E.

Does not assign the returned storage location to E in the environment. Does not assign a value to the returned storage location in the environment.

Definition at line 844 of file DataflowEnvironment.cpp.

References E, and clang::dataflow::DataflowAnalysisContext::getStableStorageLocation().

◆ createStorageLocation() [2/3]

StorageLocation & clang::dataflow::Environment::createStorageLocation ( const ValueDecl & D )

Creates a storage location for D.

Does not assign the returned storage location to D in the environment. Does not assign a value to the returned storage location in the environment.

Definition at line 837 of file DataflowEnvironment.cpp.

References D, and clang::dataflow::DataflowAnalysisContext::getStableStorageLocation().

◆ createStorageLocation() [3/3]

StorageLocation & clang::dataflow::Environment::createStorageLocation ( QualType Type )

Creates a storage location appropriate for Type.

Does not assign a value to the returned storage location in the environment.

Requirements:

Type must not be null.

Definition at line 833 of file DataflowEnvironment.cpp.

References clang::dataflow::DataflowAnalysisContext::createStorageLocation().

Referenced by clang::dataflow::CachedConstAccessorsLattice< Base >::getOrCreateConstMethodReturnStorageLocation(), initialize(), and setStorageLocation().

◆ createValue()

Value * clang::dataflow::Environment::createValue ( QualType Type )

Creates a value appropriate for Type, if Type is supported, otherwise returns null.

If Type is a pointer or reference type, creates all the necessary storage locations and values for indirections until it finds a non-pointer/non-reference type.

If Type is one of the following types, this function will always return a non-null pointer:

bool
Any integer type

Requirements:

Type must not be null.
Type must not be a reference type or record type.

Definition at line 967 of file DataflowEnvironment.cpp.

References clang::dataflow::MaxCompositeValueSize, and Visited.

Referenced by clang::dataflow::CachedConstAccessorsLattice< Base >::getOrCreateConstMethodReturnValue(), and clang::dataflow::joinDistinctValues().

◆ dump() [1/2]

void clang::dataflow::Environment::dump ( ) const

Definition at line 1203 of file DataflowEnvironment.cpp.

References dump().

Referenced by dump(), and clang::dataflow::runTypeErasedDataflowAnalysis().

◆ dump() [2/2]

void clang::dataflow::Environment::dump ( raw_ostream & OS ) const

Definition at line 1150 of file DataflowEnvironment.cpp.

References D, clang::dataflow::DataflowAnalysisContext::dumpFlowCondition(), E, clang::Func, getCurrentFunc(), Iter, and V.

◆ equivalentTo()

bool clang::dataflow::Environment::equivalentTo	(	const Environment &	Other,
		Environment::ValueModel &	Model
	)		const

Returns true if and only if the environment is equivalent to Other, i.e the two environments:

have the same mappings from declarations to storage locations,
have the same mappings from expressions to storage locations,
have the same or equivalent (according to Model) values assigned to the same storage locations.

Requirements:

Other and this must use the same DataflowAnalysisContext.

Definition at line 694 of file DataflowEnvironment.cpp.

References clang::dataflow::compareKeyToValueMaps(), and clang::Other.

◆ fork()

Environment clang::dataflow::Environment::fork ( ) const

Returns a new environment that is a copy of this one.

The state of the program is initially the same, but can be mutated without affecting the original.

However the original should not be further mutated, as this may interfere with the fork. (In practice, values are stored independently, but the forked flow condition references the original).

Definition at line 595 of file DataflowEnvironment.cpp.

References clang::Copy, and clang::dataflow::DataflowAnalysisContext::forkFlowCondition().

Referenced by clang::dataflow::TypeErasedDataflowAnalysisState::fork(), and clang::dataflow::runTypeErasedDataflowAnalysis().

◆ get() [1/5]

template<typename T >

std::enable_if_t< std::is_base_of_v< StorageLocation, T >, T * > clang::dataflow::Environment::get ( const Expr & E ) const

inline

Definition at line 347 of file DataflowEnvironment.h.

References E, and getStorageLocation().

◆ get() [2/5]

template<typename T >

std::enable_if_t< std::is_base_of_v< Value, T >, T * > clang::dataflow::Environment::get ( const Expr & E ) const

inline

Definition at line 544 of file DataflowEnvironment.h.

References E, and getValue().

◆ get() [3/5]

template<typename T >

std::enable_if_t< std::is_base_of_v< Value, T >, T * > clang::dataflow::Environment::get ( const StorageLocation & Loc ) const

inline

Returns the result of casting getValue(...) to a subclass of Value (using cast_or_null<T>).

This assert-fails if the result of getValue(...) is not of type T *; if the value is not guaranteed to have type T *, consider using dyn_cast_or_null<T>(getValue(...)) instead.

Definition at line 535 of file DataflowEnvironment.h.

References getValue(), and Loc.

◆ get() [4/5]

template<typename T >

std::enable_if_t< std::is_base_of_v< StorageLocation, T >, T * > clang::dataflow::Environment::get ( const ValueDecl & D ) const

inline

Returns the result of casting getStorageLocation(...) to a subclass of StorageLocation (using cast_or_null<T>).

This assert-fails if the result of getStorageLocation(...) is not of type T *; if the storage location is not guaranteed to have type T *, consider using dyn_cast_or_null<T>(getStorageLocation(...)) instead.

Definition at line 342 of file DataflowEnvironment.h.

References D, and getStorageLocation().

Referenced by clang::dataflow::getBaseObjectLocation(), and clang::dataflow::getImplicitObjectLocation().

◆ get() [5/5]

template<typename T >

std::enable_if_t< std::is_base_of_v< Value, T >, T * > clang::dataflow::Environment::get ( const ValueDecl & D ) const

inline

Definition at line 540 of file DataflowEnvironment.h.

References D, and getValue().

◆ getBoolLiteralValue()

BoolValue & clang::dataflow::Environment::getBoolLiteralValue ( bool Value ) const

inline

Returns a symbolic boolean value that models a boolean literal equal to Value

Definition at line 569 of file DataflowEnvironment.h.

References arena(), and clang::dataflow::Arena::makeBoolValue().

Referenced by clang::dataflow::evaluateBooleanEquality(), and clang::dataflow::widenDistinctValues().

◆ getCurrentFunc()

const FunctionDecl * clang::dataflow::Environment::getCurrentFunc ( ) const

inline

Returns the function currently being analyzed, or null if the code being analyzed isn't part of a function.

Definition at line 662 of file DataflowEnvironment.h.

Referenced by dump(), getReturnStorageLocation(), getReturnValue(), join(), setReturnStorageLocation(), and setReturnValue().

◆ getDataflowAnalysisContext()

DataflowAnalysisContext & clang::dataflow::Environment::getDataflowAnalysisContext ( ) const

inline

Returns the DataflowAnalysisContext used by the environment.

Definition at line 677 of file DataflowEnvironment.h.

Referenced by clang::dataflow::unpackValue().

◆ getFlowConditionToken()

Atom clang::dataflow::Environment::getFlowConditionToken ( ) const

inline

Returns a boolean variable that identifies the flow condition (FC).

The flow condition is a set of facts that are necessarily true when the program reaches the current point, expressed as boolean formulas. The flow condition token is equivalent to the AND of these facts.

These may e.g. constrain the value of certain variables. A pointer variable may have a consistent modeled PointerValue throughout, but at a given point the Environment may tell us that the value must be non-null.

The FC is necessary but not sufficient for this point to be reachable. In particular, where the FC token appears in flow conditions of successor environments, it means "point X may have been reached", not "point X was reached".

Definition at line 639 of file DataflowEnvironment.h.

Referenced by clang::dataflow::joinDistinctValues().

◆ getIntLiteralValue()

IntegerValue & clang::dataflow::Environment::getIntLiteralValue ( llvm::APInt Value ) const

inline

Returns a symbolic integer value that models an integer literal equal to Value

Definition at line 563 of file DataflowEnvironment.h.

References arena(), and clang::dataflow::Arena::makeIntLiteral().

◆ getOrCreateNullPointerValue()

PointerValue & clang::dataflow::Environment::getOrCreateNullPointerValue ( QualType PointeeType )

Returns a pointer value that represents a null pointer.

Calls with PointeeType that are canonically equivalent will return the same result.

Definition at line 909 of file DataflowEnvironment.cpp.

References clang::dataflow::DataflowAnalysisContext::getOrCreateNullPointerValue().

◆ getResultObjectLocation()

RecordStorageLocation & clang::dataflow::Environment::getResultObjectLocation ( const Expr & RecordPRValue ) const

Returns the location of the result object for a record-type prvalue.

In C++, prvalues of record type serve only a limited purpose: They can only be used to initialize a result object (e.g. a variable or a temporary). This function returns the location of that result object.

When creating a prvalue of record type, we already need the storage location of the result object to pass in this, even though prvalues are otherwise not associated with storage locations.

Requirements: E must be a prvalue of record type.

Definition at line 894 of file DataflowEnvironment.cpp.

References clang::dataflow::DataflowAnalysisContext::getStableStorageLocation(), clang::Expr::getType(), clang::Expr::isPRValue(), clang::Type::isRecordType(), and Loc.

◆ getReturnStorageLocation()

StorageLocation * clang::dataflow::Environment::getReturnStorageLocation ( ) const

inline

Returns the storage location for the reference returned by the function currently being analyzed.

This can be null if the function doesn't return a single consistent reference.

Requirements: The current analysis target must be a function and must have a reference return type.

Definition at line 401 of file DataflowEnvironment.h.

References getCurrentFunc().

◆ getReturnValue()

Value * clang::dataflow::Environment::getReturnValue ( ) const

inline

Returns the return value of the function currently being analyzed.

This can be null if:

The function has a void return type
No return value could be determined for the function, for example because it calls a function without a body.

Requirements: The current analysis target must be a function and must have a non-reference return type.

Definition at line 388 of file DataflowEnvironment.h.

References getCurrentFunc().

◆ getStorageLocation() [1/2]

StorageLocation * clang::dataflow::Environment::getStorageLocation ( const Expr & E ) const

Returns the storage location assigned to the glvalue E in the environment, or null if E isn't assigned a storage location in the environment.

Requirements: E must be a glvalue or a BuiltinType::BuiltinFn

Definition at line 885 of file DataflowEnvironment.cpp.

References E, and clang::dataflow::ignoreCFGOmittedNodes().

◆ getStorageLocation() [2/2]

StorageLocation * clang::dataflow::Environment::getStorageLocation ( const ValueDecl & D ) const

Returns the storage location assigned to D in the environment, or null if D isn't assigned a storage location in the environment.

Definition at line 862 of file DataflowEnvironment.cpp.

References D, and Loc.

Referenced by get(), clang::dataflow::getImplicitObjectLocation(), getValue(), clang::dataflow::maybeUnpackLValueExpr(), clang::dataflow::propagateStorageLocation(), and pushCall().

◆ getThisPointeeStorageLocation()

RecordStorageLocation * clang::dataflow::Environment::getThisPointeeStorageLocation ( ) const

inline

Returns the storage location assigned to the this pointee in the environment or null if the this pointee has no assigned storage location in the environment.

Definition at line 354 of file DataflowEnvironment.h.

Referenced by initialize().

◆ getValue() [1/3]

Value * clang::dataflow::Environment::getValue ( const Expr & E ) const

Equivalent to getValue(getStorageLocation(E, SP)) if E is assigned a storage location in the environment, otherwise returns null.

Definition at line 952 of file DataflowEnvironment.cpp.

References E, getValue(), and clang::dataflow::ignoreCFGOmittedNodes().

◆ getValue() [2/3]

Value * clang::dataflow::Environment::getValue ( const StorageLocation & Loc ) const

Returns the value assigned to Loc in the environment or null if Loc isn't assigned a value in the environment.

Requirements:

Loc must not be a RecordStorageLocation.

Definition at line 939 of file DataflowEnvironment.cpp.

References Loc.

Referenced by clang::dataflow::copyField(), clang::dataflow::copySyntheticField(), clang::dataflow::evaluateBooleanEquality(), get(), getValue(), clang::dataflow::maybeUnpackLValueExpr(), clang::dataflow::propagateValue(), and clang::dataflow::recordsEqual().

◆ getValue() [3/3]

Value * clang::dataflow::Environment::getValue ( const ValueDecl & D ) const

Equivalent to getValue(getStorageLocation(D)) if D is assigned a storage location in the environment, otherwise returns null.

Requirements:

D must not have record type.

Definition at line 945 of file DataflowEnvironment.cpp.

References D, getStorageLocation(), getValue(), and Loc.

◆ initialize()

void clang::dataflow::Environment::initialize ( )

Assigns storage locations and values to all parameters, captures, global variables, fields and functions referenced in the Stmt or FunctionDecl passed to the constructor.

If no Stmt or FunctionDecl was supplied, this function does nothing.

Definition at line 494 of file DataflowEnvironment.cpp.

References createObject(), createStorageLocation(), clang::DeclContext::getNonClosureAncestor(), clang::dataflow::getReferencedDecls(), clang::FunctionDecl::getReturnType(), getThisPointeeStorageLocation(), initializeFieldsWithValues(), clang::Type::isRecordType(), clang::FunctionDecl::parameters(), Parent, setStorageLocation(), and setThisPointeeStorageLocation().

◆ initializeFieldsWithValues() [1/2]

void clang::dataflow::Environment::initializeFieldsWithValues ( RecordStorageLocation & Loc )

inline

Definition at line 486 of file DataflowEnvironment.h.

References initializeFieldsWithValues(), and Loc.

◆ initializeFieldsWithValues() [2/2]

void clang::dataflow::Environment::initializeFieldsWithValues	(	RecordStorageLocation &	Loc,
		QualType	Type
	)

Initializes the fields (including synthetic fields) of Loc with values, unless values of the field type are not supported or we hit one of the limits at which we stop producing values.

If a field already has a value, that value is preserved. If Type is provided, initializes only those fields that are modeled for Type; this is intended for use in cases where Loc is a derived type and we only want to initialize the fields of a base type.

Definition at line 913 of file DataflowEnvironment.cpp.

References initializeFieldsWithValues(), Loc, clang::dataflow::MaxCompositeValueSize, and Visited.

Referenced by initialize(), and initializeFieldsWithValues().

◆ join()

Environment clang::dataflow::Environment::join	(	const Environment &	EnvA,
		const Environment &	EnvB,
		Environment::ValueModel &	Model,
		ExprJoinBehavior	ExprBehavior
	)

static

Joins two environments by taking the intersection of storage locations and values that are stored in them.

Distinct values that are assigned to the same storage locations in EnvA and EnvB are merged using Model.

Requirements:

EnvA and EnvB must use the same DataflowAnalysisContext.

Definition at line 763 of file DataflowEnvironment.cpp.

References clang::Func, getCurrentFunc(), clang::dataflow::intersectDeclToLoc(), clang::dataflow::joinExprMaps(), clang::dataflow::DataflowAnalysisContext::joinFlowConditions(), clang::dataflow::joinLocToVal(), joinValues(), and KeepExprState.

◆ joinValues()

Value * clang::dataflow::Environment::joinValues	(	QualType	Ty,
		Value *	Val1,
		const Environment &	Env1,
		Value *	Val2,
		const Environment &	Env2,
		Environment &	JoinedEnv,
		Environment::ValueModel &	Model
	)

static

Returns a value that approximates both Val1 and Val2, or null if no such value can be produced.

Env1 and Env2 can be used to query child values and path condition implications of Val1 and Val2 respectively. The joined value will be produced in JoinedEnv.

Requirements:

Val1 and Val2 must model values of type Type.

Definition at line 815 of file DataflowEnvironment.cpp.

References clang::dataflow::areEquivalentValues(), and clang::dataflow::joinDistinctValues().

Referenced by join(), and clang::dataflow::joinLocToVal().

◆ makeAnd()

BoolValue & clang::dataflow::Environment::makeAnd	(	BoolValue &	LHS,
		BoolValue &	RHS
	)		const

inline

Returns a boolean value that represents the conjunction of LHS and RHS.

Subsequent calls with the same arguments, regardless of their order, will return the same result. If the given boolean values represent the same value, the result will be the value itself.

Definition at line 587 of file DataflowEnvironment.h.

References arena(), clang::dataflow::BoolValue::formula(), makeAnd(), and clang::dataflow::Arena::makeBoolValue().

Referenced by makeAnd().

◆ makeAtomicBoolValue()

BoolValue & clang::dataflow::Environment::makeAtomicBoolValue ( ) const

inline

Returns an atomic boolean value.

Definition at line 574 of file DataflowEnvironment.h.

References arena(), and clang::dataflow::Arena::makeAtomValue().

Referenced by clang::dataflow::evaluateBooleanEquality().

◆ makeIff()

BoolValue & clang::dataflow::Environment::makeIff	(	BoolValue &	LHS,
		BoolValue &	RHS
	)		const

inline

Returns a boolean value represents LHS <=> RHS.

Subsequent calls with the same arguments, regardless of their order, will return the same result. If the given boolean values represent the same value, the result will be a value that represents the true boolean literal.

Definition at line 620 of file DataflowEnvironment.h.

References arena(), clang::dataflow::BoolValue::formula(), and clang::dataflow::Arena::makeBoolValue().

Referenced by clang::dataflow::evaluateBooleanEquality().

◆ makeImplication()

BoolValue & clang::dataflow::Environment::makeImplication	(	BoolValue &	LHS,
		BoolValue &	RHS
	)		const

inline

Returns a boolean value represents LHS => RHS.

Subsequent calls with the same arguments, will return the same result. If the given boolean values represent the same value, the result will be a value that represents the true boolean literal.

Definition at line 611 of file DataflowEnvironment.h.

References arena(), clang::dataflow::BoolValue::formula(), and clang::dataflow::Arena::makeBoolValue().

◆ makeNot()

BoolValue & clang::dataflow::Environment::makeNot ( BoolValue & Val ) const

inline

Returns a boolean value that represents the negation of Val.

Subsequent calls with the same argument will return the same result.

Definition at line 603 of file DataflowEnvironment.h.

References arena(), clang::dataflow::BoolValue::formula(), clang::dataflow::Arena::makeBoolValue(), and makeNot().

Referenced by makeNot().

◆ makeOr()

BoolValue & clang::dataflow::Environment::makeOr	(	BoolValue &	LHS,
		BoolValue &	RHS
	)		const

inline

Returns a boolean value that represents the disjunction of LHS and RHS.

Subsequent calls with the same arguments, regardless of their order, will return the same result. If the given boolean values represent the same value, the result will be the value itself.

Definition at line 596 of file DataflowEnvironment.h.

References arena(), clang::dataflow::BoolValue::formula(), clang::dataflow::Arena::makeBoolValue(), and makeOr().

Referenced by makeOr().

◆ makeTopBoolValue()

BoolValue & clang::dataflow::Environment::makeTopBoolValue ( ) const

inline

Returns a unique instance of boolean Top.

Definition at line 579 of file DataflowEnvironment.h.

References arena(), and clang::dataflow::Arena::makeTopValue().

Referenced by clang::dataflow::widenDistinctValues().

◆ operator=() [1/2]

Environment & clang::dataflow::Environment::operator= ( const Environment & Other )

delete

◆ operator=() [2/2]

Environment & clang::dataflow::Environment::operator= ( Environment && Other )

default

◆ popCall() [1/2]

void clang::dataflow::Environment::popCall	(	const CallExpr *	Call,
		const Environment &	CalleeEnv
	)

Moves gathered information back into this from a CalleeEnv created via pushCall.

Definition at line 667 of file DataflowEnvironment.cpp.

References clang::Call, setStorageLocation(), and setValue().

◆ popCall() [2/2]

void clang::dataflow::Environment::popCall	(	const CXXConstructExpr *	Call,
		const Environment &	CalleeEnv
	)

Definition at line 687 of file DataflowEnvironment.cpp.

◆ proves()

bool clang::dataflow::Environment::proves ( const Formula & F ) const

Returns true if the formula is always true when this point is reached.

Returns false if the formula may be false (or the flow condition isn't sufficiently precise to prove that it is true) or if the solver times out.

Note that there is an asymmetry between this function and allows() in that they both return false if the solver times out. The assumption is that if proves() or allows() returns true, this will result in a diagnostic, and we want to bias towards false negatives in the case where the solver times out.

Definition at line 1142 of file DataflowEnvironment.cpp.

References clang::dataflow::DataflowAnalysisContext::flowConditionImplies().

Referenced by clang::dataflow::widenDistinctValues().

◆ pushCall() [1/2]

Environment clang::dataflow::Environment::pushCall ( const CallExpr * Call ) const

Creates and returns an environment to use for an inline analysis of the callee.

Uses the storage location from each argument in the Call as the storage location for the corresponding parameter in the callee.

Requirements:

The callee of Call must be a FunctionDecl.

The body of the callee must not reference globals.

The arguments of Call must map 1:1 to the callee's parameters.

Definition at line 606 of file DataflowEnvironment.cpp.

References clang::Call, Env, and getStorageLocation().

◆ pushCall() [2/2]

Environment clang::dataflow::Environment::pushCall ( const CXXConstructExpr * Call ) const

Definition at line 628 of file DataflowEnvironment.cpp.

References clang::Call, and Env.

◆ removeDecl()

void clang::dataflow::Environment::removeDecl ( const ValueDecl & D )

Removes the location assigned to D in the environment (if any).

Definition at line 872 of file DataflowEnvironment.cpp.

References D.

◆ setReturnStorageLocation()

void clang::dataflow::Environment::setReturnStorageLocation ( StorageLocation * Loc )

inline

Sets the storage location for the reference returned by the function currently being analyzed.

Requirements: The current analysis target must be a function and must have a reference return type.

Definition at line 424 of file DataflowEnvironment.h.

References getCurrentFunc(), and Loc.

◆ setReturnValue()

void clang::dataflow::Environment::setReturnValue ( Value * Val )

inline

Sets the return value of the function currently being analyzed.

Requirements: The current analysis target must be a function and must have a non-reference return type.

Definition at line 412 of file DataflowEnvironment.h.

References getCurrentFunc().

◆ setStorageLocation() [1/2]

void clang::dataflow::Environment::setStorageLocation	(	const Expr &	E,
		StorageLocation &	Loc
	)

Assigns Loc as the storage location of the glvalue E in the environment.

Requirements:

E must not be assigned a storage location in the environment. E must be a glvalue or a BuiltinType::BuiltinFn

Definition at line 874 of file DataflowEnvironment.cpp.

References E, clang::dataflow::ignoreCFGOmittedNodes(), and Loc.

◆ setStorageLocation() [2/2]

void clang::dataflow::Environment::setStorageLocation	(	const ValueDecl &	D,
		StorageLocation &	Loc
	)

Assigns Loc as the storage location of D in the environment.

Requirements:

D must not already have a storage location in the environment.

Definition at line 851 of file DataflowEnvironment.cpp.

References createStorageLocation(), D, and Loc.

Referenced by initialize(), popCall(), and clang::dataflow::propagateStorageLocation().

◆ setThisPointeeStorageLocation()

void clang::dataflow::Environment::setThisPointeeStorageLocation ( RecordStorageLocation & Loc )

inline

Sets the storage location assigned to the this pointee in the environment.

Definition at line 360 of file DataflowEnvironment.h.

References Loc.

Referenced by initialize().

◆ setValue() [1/2]

void clang::dataflow::Environment::setValue	(	const Expr &	E,
		Value &	Val
	)

Assigns Val as the value of the prvalue E in the environment.

Requirements:

E must be a prvalue.
E must not have record type.

Definition at line 930 of file DataflowEnvironment.cpp.

References E, clang::Expr::getType(), clang::dataflow::ignoreCFGOmittedNodes(), clang::Expr::isPRValue(), and clang::Type::isRecordType().

◆ setValue() [2/2]

void clang::dataflow::Environment::setValue	(	const StorageLocation &	Loc,
		Value &	Val
	)

Assigns Val as the value of Loc in the environment.

Requirements:

Loc must not be a RecordStorageLocation.

Definition at line 924 of file DataflowEnvironment.cpp.

References Loc.

Referenced by clang::dataflow::copyField(), clang::dataflow::copySyntheticField(), clang::dataflow::maybeUnpackLValueExpr(), popCall(), and clang::dataflow::propagateValue().

◆ widen()

LatticeEffect clang::dataflow::Environment::widen	(	const Environment &	PrevEnv,
		Environment::ValueModel &	Model
	)

Widens the environment point-wise, using PrevEnv as needed to inform the approximation.

Requirements:

PrevEnv must be the immediate previous version of the environment. PrevEnv and this must use the same DataflowAnalysisContext.

Definition at line 725 of file DataflowEnvironment.cpp.

References clang::dataflow::Changed, clang::dataflow::Unchanged, and clang::dataflow::widenKeyToValueMap().

Referenced by clang::dataflow::runTypeErasedDataflowAnalysis().

The documentation for this class was generated from the following files:

include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
lib/Analysis/FlowSensitive/DataflowEnvironment.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ ExprJoinBehavior

Constructor & Destructor Documentation

◆ Environment() [1/4]

◆ Environment() [2/4]

◆ Environment() [3/4]

◆ Environment() [4/4]

Member Function Documentation

◆ allows()

◆ arena()

◆ assume()

◆ callStackSize()

◆ canDescend()

◆ clearValue()

◆ create()

◆ createObject() [1/3]

◆ createObject() [2/3]

◆ createObject() [3/3]

◆ createStorageLocation() [1/3]

◆ createStorageLocation() [2/3]

◆ createStorageLocation() [3/3]

◆ createValue()

◆ dump() [1/2]

◆ dump() [2/2]

◆ equivalentTo()

◆ fork()

◆ get() [1/5]

◆ get() [2/5]

◆ get() [3/5]

◆ get() [4/5]

◆ get() [5/5]

◆ getBoolLiteralValue()

◆ getCurrentFunc()

◆ getDataflowAnalysisContext()

◆ getFlowConditionToken()

◆ getIntLiteralValue()

◆ getOrCreateNullPointerValue()

◆ getResultObjectLocation()

◆ getReturnStorageLocation()

◆ getReturnValue()

◆ getStorageLocation() [1/2]

◆ getStorageLocation() [2/2]

◆ getThisPointeeStorageLocation()

◆ getValue() [1/3]

◆ getValue() [2/3]

◆ getValue() [3/3]

◆ initialize()

◆ initializeFieldsWithValues() [1/2]

◆ initializeFieldsWithValues() [2/2]

◆ join()

◆ joinValues()

◆ makeAnd()

◆ makeAtomicBoolValue()

◆ makeIff()

◆ makeImplication()

◆ makeNot()

◆ makeOr()

◆ makeTopBoolValue()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ popCall() [1/2]

◆ popCall() [2/2]

◆ proves()

◆ pushCall() [1/2]

◆ pushCall() [2/2]

◆ removeDecl()

◆ setReturnStorageLocation()

◆ setReturnValue()

◆ setStorageLocation() [1/2]

◆ setStorageLocation() [2/2]

◆ setThisPointeeStorageLocation()

◆ setValue() [1/2]

◆ setValue() [2/2]

◆ widen()