org.multijava.mjc
Interface CFlowControlContextType

All Superinterfaces:

CContextType

All Known Implementing Classes:

CFinallyContext, CFlowControlContext, JmlFlowControlContext

public interface CFlowControlContextType

extends CContextType

This class is used during typechecking for control flow analysis that maintains local variable definite assignment (JLS2, 16), throwable, and reachability information (JLS2, 14.20).

Method Summary
void	addLocalClass(CClass clazz)           Adds to this context a class declared via a type declaration statement.
void	addSyntheticThisParameter()           Records that a variable slot must be reserved for a synthetic this parameter.
void	addThisVariable()           Records that the Java keyword this is used in this block.
void	addThrowable(CThrowableInfo throwable)           Registers that the given throwable can be thrown within this context.
void	addVariable(JLocalVariable var)           Adds a local variable to this block
void	adopt(CFlowControlContextType context)
void	adoptParallelContexts(CFlowControlContextType[] contexts)           Adopts the information from the given contexts.
void	checkingComplete()           Registers that this context is no longer needed.
CFlowControlContextType	cloneContext()           Create a clone of this context to handle divergent paths in the control flow.
CExpressionContextType	createExpressionContext()
CFlowControlContextType	createFinallyContext(CFlowControlContextType tryContext, TokenReference where)
CFlowControlContextType	createFlowControlContext(int params, TokenReference where)
CFlowControlContextType	createFlowControlContext(TokenReference where)
CLabeledContext	createLabeledContext(JLabeledStatement self)
CLoopContext	createLoopContext(JLoopStatement self)
CFlowControlContextType[]	createParallelContexts(int count, TokenReference where)           Creates a set of child contexts for typechecking parallel control flows.
CSwitchBodyContext	createSwitchBodyContext(JSwitchStatement stmt, CType switchType)
CTryContext	createTryContext(TokenReference where)
CVariableInfoTable	fieldInfo()           Returns the field info table
CFlowControlContextType	getFlowControlContext()           Returns the nearest control flow context (where control flow information is stored.)
JLabeledStatement	getLabeledStatement(String label)           Returns the statement with the specified label.
JStatement	getNearestBreakableStatement()           Returns the nearest breakable statement.
JStatement	getNearestContinuableStatement()           Returns the nearest continuable statement.
TokenReference	getTokenReference()
void	initializeField(VariableDescriptor varDesc)           Marks the field with the given descriptor as definitely assigned to in this context.
void	initializeVariable(VariableDescriptor varDesc)           Marks the variable with the given descriptor as definitely assigned to in this context.
boolean	isFieldDefinitelyAssigned(int pos)           Indicates whether the field in the given position is definitely assigned to in this context.
boolean	isFreshVariableName(JLocalVariable var)           Checks whether a local variable has a name that is fresh (i.e., no other local variable in scope has the same name).
boolean	isReachable()           Indicates whether the statements in this context are reachable up to most recent statement that was typechecked.
boolean	isVarDefinitelyAssigned(int pos)           Indicates whether the variable in the given position is definitely assigned to in this context.
boolean	isVarDefinitelyUnassigned(int i)           Indicates whether the variable in the given position is definitely unassigned to in this context
int	localsIndex()
int	localsPosition()           Returns the number of stack positions required to store the local variables encountered thus far in this context.
ArrayList	localVars()           Returns the local variables list
CClass	lookupClass(String name)           Searches for a class with the given simple name according the procedure in JLS2 6.5.5.
void	merge(CFlowControlContextType context)
int	numberOfLocalVars()
int	parentIndex()
void	replaceFieldInfoUpTo(int pos, CVariableInfoTable replacement)           Replaces the local field info for fields in positions 0 up to pos with the info in replacement.
void	replaceVariableInfoUpTo(int pos, CVariableInfoTable replacement)           Replaces the local variable info in positions 0 up to pos with the info in replacement.
void	setReachable(boolean reachable)           Mutates the reachability status of this context.
CVariableInfoTable	variableInfo()           Returns the variable info table

 

Methods inherited from interface org.multijava.mjc.CContextType

addFANonNull, addFANonNulls, addFANull, addFANulls, adoptNullityInfo, arithmeticMode, catchUp, check, check, check, check, classToGenerate, createClassContext, createExtMethodContext, createInterfaceContext, declaredOutsideOfLoop, declares, dumpNonNulls, fail, fail, findNearestHost, getClassContext, getCMethod, getCompilationUnit, getCompiler, getFANonNulls, getFANulls, getMethodContext, getParentContext, isBeforeSuperConstructorCall, isFANonNull, isInConstructor, isInInitializer, isInLoop, isPure, isStatic, lookupField, lookupField, lookupLocalVariable, lookupMethod, lookupMethod, lookupMethodOrSet, lookupMethodOrSet, lookupOuterField, lookupOuterField, lookupOuterLocalVariable, lookupTypeVariable, mergeNullityInfo, modUtil, registerGFDecl, registerVisibleMethod, registerVisibleType, removeAllFANullity, removeFANonNull, reportTrouble, resolveMaybeExtMethodRef

 

Method Detail

checkingComplete

public void checkingComplete()

Registers that this context is no longer needed. Passes information collected by this context to the parent context.

Passes this context's field information to the surrounding context; passes local variable information to the surrounding context if that context is one which maintains local variable information.

Checks that local variables are used and issues warnings if not.

This should only be called on a linearly nested context! !FIXME!10/26 If we refactor the context creation code as planned (to lock the parent context) then this method is called to unlock the parent context when we exit a linearly nested context.

getTokenReference

public TokenReference getTokenReference()

createFlowControlContext

public CFlowControlContextType createFlowControlContext(TokenReference where)

createFlowControlContext

public CFlowControlContextType createFlowControlContext(int params,
                                                        TokenReference where)

createLabeledContext

public CLabeledContext createLabeledContext(JLabeledStatement self)

createLoopContext

public CLoopContext createLoopContext(JLoopStatement self)

createSwitchBodyContext

public CSwitchBodyContext createSwitchBodyContext(JSwitchStatement stmt,
                                                  CType switchType)

createTryContext

public CTryContext createTryContext(TokenReference where)

createFinallyContext

public CFlowControlContextType createFinallyContext(CFlowControlContextType tryContext,
                                                    TokenReference where)

createExpressionContext

public CExpressionContextType createExpressionContext()

cloneContext

public CFlowControlContextType cloneContext()

Create a clone of this context to handle divergent paths in the control flow.

createParallelContexts

public CFlowControlContextType[] createParallelContexts(int count,
                                                        TokenReference where)

Creates a set of child contexts for typechecking parallel control flows. After using the contexts they should be passed to the adoptParallelContexts method of this.

 requires count > 0;
 

See Also:

adoptParallelContexts(CFlowControlContextType[])

adoptParallelContexts

public void adoptParallelContexts(CFlowControlContextType[] contexts)

Adopts the information from the given contexts.

 requires contexts != null && contexts.length > 0;
 

merge

public void merge(CFlowControlContextType context)

adopt

public void adopt(CFlowControlContextType context)

isFreshVariableName

public boolean isFreshVariableName(JLocalVariable var)

Checks whether a local variable has a name that is fresh (i.e., no other local variable in scope has the same name).

Parameters:

var - the variable

addVariable

public void addVariable(JLocalVariable var)
                          throws UnpositionedError

Adds a local variable to this block

Parameters:

var - the name of the variable

Throws:

UnpositionedError - if the variable is a redeclaration

addThisVariable

public void addThisVariable()

Records that the Java keyword this is used in this block.

addSyntheticThisParameter

public void addSyntheticThisParameter()

Records that a variable slot must be reserved for a synthetic this parameter. Recall that this is passed as a parameter for external methods.

localsPosition

public int localsPosition()

Returns the number of stack positions required to store the local variables encountered thus far in this context.

numberOfLocalVars

public int numberOfLocalVars()

variableInfo

public CVariableInfoTable variableInfo()

Returns the variable info table

fieldInfo

public CVariableInfoTable fieldInfo()

Returns the field info table

localVars

public ArrayList localVars()

Returns the local variables list

parentIndex

public int parentIndex()

localsIndex

public int localsIndex()

setReachable

public void setReachable(boolean reachable)

Mutates the reachability status of this context.

Parameters:

reachable - indicates whether the statements in this context are reachable after the current statement being checked.

isReachable

public boolean isReachable()

Indicates whether the statements in this context are reachable up to most recent statement that was typechecked. (Assuming that statement's typechecking code calls setReachable appropriately.)

Returns:

if this context is still reachable

getLabeledStatement

public JLabeledStatement getLabeledStatement(String label)

Returns the statement with the specified label.

getNearestBreakableStatement

public JStatement getNearestBreakableStatement()

Returns the nearest breakable statement.

getNearestContinuableStatement

public JStatement getNearestContinuableStatement()

Returns the nearest continuable statement.

getFlowControlContext

public CFlowControlContextType getFlowControlContext()

Returns the nearest control flow context (where control flow information is stored.)

Specified by:

getFlowControlContext in interface CContextType

Returns:

the nearest parent of type CFlowControlContextType

initializeVariable

public void initializeVariable(VariableDescriptor varDesc)

Marks the variable with the given descriptor as definitely assigned to in this context.

isVarDefinitelyAssigned

public boolean isVarDefinitelyAssigned(int pos)

Indicates whether the variable in the given position is definitely assigned to in this context.

isVarDefinitelyUnassigned

public boolean isVarDefinitelyUnassigned(int i)

Indicates whether the variable in the given position is definitely unassigned to in this context

Parameters:

i - stack position

Returns:

true iff the variable is definitely unassigned

replaceFieldInfoUpTo

public void replaceFieldInfoUpTo(int pos,
                                 CVariableInfoTable replacement)

Replaces the local field info for fields in positions 0 up to pos with the info in replacement.

Specified by:

replaceFieldInfoUpTo in interface CContextType

replaceVariableInfoUpTo

public void replaceVariableInfoUpTo(int pos,
                                    CVariableInfoTable replacement)

Replaces the local variable info in positions 0 up to pos with the info in replacement.

initializeField

public void initializeField(VariableDescriptor varDesc)

Marks the field with the given descriptor as definitely assigned to in this context.

Specified by:

initializeField in interface CContextType

isFieldDefinitelyAssigned

public boolean isFieldDefinitelyAssigned(int pos)

Indicates whether the field in the given position is definitely assigned to in this context.

Specified by:

isFieldDefinitelyAssigned in interface CContextType

addLocalClass

public void addLocalClass(CClass clazz)
                            throws UnpositionedError

Adds to this context a class declared via a type declaration statement.

Parameters:

clazz - the clazz to add

Throws:

UnpositionedError - if duplicate class exists in this lexical context

lookupClass

public CClass lookupClass(String name)
                            throws UnpositionedError

Searches for a class with the given simple name according the procedure in JLS2 6.5.5. This method checks the first bullet point of that section: "If the simple type name occurs within the scope of a visible local class declaration with that name, then the simple type name denotes that local class type." If no match is found, then this method calls to the surrounding context to check the remaining bullet points.

Specified by:

lookupClass in interface CContextType

Parameters:

name - the class name, without qualifiers

Returns:

the class if found, null otherwise

Throws:

UnpositionedError - if search fails

addThrowable

public void addThrowable(CThrowableInfo throwable)

Registers that the given throwable can be thrown within this context. The implementation passes the throwable up through the nested contexts until a surrounding context is found that can handle throwables. For example, a CMethodContextType instance collects the throwables that are uncaught within a method body, while a CTryContext collects the throwables that are thrown within a try-block and are therefore subject to handling by associated catch-blocks.

Parameters:

throwable - the type of the new throwable