com.google.javascript.jscomp

Class MustBeReachingVariableDef

java.lang.Object

com.google.javascript.jscomp.DataFlowAnalysis<Node,MustBeReachingVariableDef.MustDef>

com.google.javascript.jscomp.MustBeReachingVariableDef

final class MustBeReachingVariableDef
extends DataFlowAnalysis<Node,MustBeReachingVariableDef.MustDef>

Computes reaching definition for all use of each variables. A definition of A in A = foo() is a reaching definition of the use of A in alert(A) if all paths from entry node must reaches that definition and it is the last definition before the use.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	MustBeReachingVariableDef.Definition Abstraction of a local variable definition.
(package private) static class	MustBeReachingVariableDef.MustDef Must reaching definition lattice representation.
private static class	MustBeReachingVariableDef.MustDefJoin

Nested classes/interfaces inherited from class com.google.javascript.jscomp.DataFlowAnalysis

DataFlowAnalysis.BranchedFlowState<L extends LatticeElement>, DataFlowAnalysis.BranchedForwardDataFlowAnalysis<N,L extends LatticeElement>, DataFlowAnalysis.FlowState<L extends LatticeElement>, DataFlowAnalysis.MaxIterationsExceededException

Field Summary

Fields

Modifier and Type	Field and Description
private AbstractCompiler	compiler
private java.util.Set<Var>	escaped
private Scope	jsScope

Fields inherited from class com.google.javascript.jscomp.DataFlowAnalysis

joinOp, MAX_STEPS, orderedWorkSet

Constructor Summary

Constructors

Constructor and Description
MustBeReachingVariableDef(ControlFlowGraph<Node> cfg, Scope jsScope, AbstractCompiler compiler)

Method Summary

Modifier and Type	Method and Description
private void	addToDefIfLocal(java.lang.String name, Node node, Node rValue, MustBeReachingVariableDef.MustDef def) Set the variable lattice for the given name to the node value in the def lattice.
private void	computeDependence(MustBeReachingVariableDef.Definition def, Node rValue) Computes all the local variables that rValue reads from and store that in the def's depends set.
private void	computeMustDef(Node n, Node cfgNode, MustBeReachingVariableDef.MustDef output, boolean conditional)
(package private) MustBeReachingVariableDef.MustDef	createEntryLattice() Gets the incoming state of the entry node.
(package private) MustBeReachingVariableDef.MustDef	createInitialEstimateLattice() Gets the state of the initial estimation at each node.
(package private) boolean	dependsOnOuterScopeVars(MustBeReachingVariableDef.Definition def)
private void	escapeParameters(MustBeReachingVariableDef.MustDef output)
(package private) MustBeReachingVariableDef.MustDef	flowThrough(Node n, MustBeReachingVariableDef.MustDef input) Computes the output state for a given node and input state.
(package private) MustBeReachingVariableDef.Definition	getDef(java.lang.String name, Node useNode) Gets the must reaching definition of a given node.
(package private) Node	getDefNode(java.lang.String name, Node useNode)
(package private) boolean	isForward() Checks whether the analysis is a forward flow analysis or backward flow analysis.
private static boolean	isParameter(Var v)

Methods inherited from class com.google.javascript.jscomp.DataFlowAnalysis

analyze, analyze, computeEscaped, flow, getCfg, getExitLatticeElement, initialize, join, joinInputs

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

jsScope

private final Scope jsScope

compiler

private final AbstractCompiler compiler

escaped

private final java.util.Set<Var> escaped

Constructor Detail

MustBeReachingVariableDef

MustBeReachingVariableDef(ControlFlowGraph<Node> cfg,
                          Scope jsScope,
                          AbstractCompiler compiler)

Method Detail

isForward

boolean isForward()

Description copied from class: DataFlowAnalysis

Checks whether the analysis is a forward flow analysis or backward flow analysis.

Specified by:

isForward in class DataFlowAnalysis<Node,MustBeReachingVariableDef.MustDef>

Returns:

true if it is a forward analysis.

createEntryLattice

MustBeReachingVariableDef.MustDef createEntryLattice()

Description copied from class: DataFlowAnalysis

Gets the incoming state of the entry node.

Specified by:

createEntryLattice in class DataFlowAnalysis<Node,MustBeReachingVariableDef.MustDef>

Returns:

Entry state.

createInitialEstimateLattice

MustBeReachingVariableDef.MustDef createInitialEstimateLattice()

Description copied from class: DataFlowAnalysis

Gets the state of the initial estimation at each node.

Specified by:

createInitialEstimateLattice in class DataFlowAnalysis<Node,MustBeReachingVariableDef.MustDef>

Returns:

Initial state.

flowThrough

MustBeReachingVariableDef.MustDef flowThrough(Node n,
                                              MustBeReachingVariableDef.MustDef input)

Description copied from class: DataFlowAnalysis

Computes the output state for a given node and input state.

Specified by:

flowThrough in class DataFlowAnalysis<Node,MustBeReachingVariableDef.MustDef>

Parameters:

n - The node.

input - Input lattice that should be read-only.

Returns:

Output lattice.

computeMustDef

private void computeMustDef(Node n,
                            Node cfgNode,
                            MustBeReachingVariableDef.MustDef output,
                            boolean conditional)

Parameters:

n - The node in question.

cfgNode - The node to add

conditional - true if the definition is not always executed.

addToDefIfLocal

private void addToDefIfLocal(java.lang.String name,
                             @Nullable
                             Node node,
                             @Nullable
                             Node rValue,
                             MustBeReachingVariableDef.MustDef def)

Set the variable lattice for the given name to the node value in the def lattice. Do nothing if the variable name is one of the escaped variable.

Parameters:

node - The CFG node where the definition should be record to. null if this is a conditional define.

escapeParameters

private void escapeParameters(MustBeReachingVariableDef.MustDef output)

isParameter

private static boolean isParameter(Var v)

computeDependence

private void computeDependence(MustBeReachingVariableDef.Definition def,
                               Node rValue)

Computes all the local variables that rValue reads from and store that in the def's depends set.

getDef

MustBeReachingVariableDef.Definition getDef(java.lang.String name,
                                            Node useNode)

Gets the must reaching definition of a given node.

Parameters:

name - name of the variable. It can only be names of local variable that are not function parameters, escaped variables or variables declared in catch.

useNode - the location of the use where the definition reaches.

getDefNode

Node getDefNode(java.lang.String name,
                Node useNode)

dependsOnOuterScopeVars

boolean dependsOnOuterScopeVars(MustBeReachingVariableDef.Definition def)