| java.lang.Object
 edu.umd.cs.findbugs.ba.Frame
| Frame | | abstract public class Frame (Code) | | Generic class for representing a Java stack frame as a dataflow value. A
frame consists of "slots", which represent the local variables and values on
the Java operand stack. Slots 0 .. getNumLocals() - 1
represent the local variables. Slots getNumLocals() ..
getNumSlots() - 1 represent the Java operand stack.
Frame is parametized by "ValueType", which is the type of value to be stored
in the Frame's slots. This type must form a lattice, according to the
abstract mergeValues() operation in the corresponding analysis class (which
should be derived from FrameDataflowAnalysis). When a Frame is constructed,
all of its slots will contain null. The analysis is responsible for
initializing created Frames with default values at the appropriate time.
Typically, only initEntryFact() will need to do this.
A Frame may have the special "TOP" value. Such frames serve as the identity
element for the meet operation operation.
A Frame may have the special "BOTTOM" value. The result of merging any frame
with BOTTOM is BOTTOM.
author:
David Hovemeyer
See Also: FrameDataflowAnalysis |
| Constructor Summary | |
| public | Frame(int numLocals)
Constructor. |
| Method Summary | |
| public Collection<ValueType> | allSlots()
| | public void | clearStack()
Clear the Java operand stack. | | public void | copyFrom(Frame<ValueType> other)
Make this Frame exactly the same as the one given as a parameter. | | public ValueType | getArgument(InvokeInstruction ins, ConstantPoolGen cpg, int i, int numArguments)
Get the ith argument passed to given method invocation. | | public ValueType | getArgument(InvokeInstruction ins, ConstantPoolGen cpg, int i, SignatureParser sigParser)
Get the ith argument passed to given method invocation.
Parameters:
ins - the method invocation instruction
Parameters:
cpg - the ConstantPoolGen for the class containing the method
Parameters:
i - index of the argument; 0 for the first argument, etc. | | public BitSet | getArgumentSet(InvokeInstruction invokeInstruction, ConstantPoolGen cpg, DataflowValueChooser<ValueType> chooser)
Get set of arguments passed to a method invocation which match given
predicate. | | public int | getArgumentSlot(int i, int numArguments)
Get the stack slot that will contain given method argument. | | public ValueType | getInstance(Instruction ins, ConstantPoolGen cpg)
Get the value corresponding to the object instance used in the given
instruction. | | public int | getInstanceSlot(Instruction ins, ConstantPoolGen cpg)
Get the slot the object instance referred to by given instruction is
located in. | | public int | getInstanceStackLocation(Instruction ins, ConstantPoolGen cpg)
Get the stack location (counting down from top of stack, starting at 0)
containing the object instance referred to by given instruction. | | public int | getLastUpdateTimestamp()
| | public int | getNumArguments(InvokeInstruction ins, ConstantPoolGen cpg)
Get the number of arguments passed to given method invocation. | | public int | getNumArgumentsIncludingObjectInstance(InvokeInstruction ins, ConstantPoolGen cpg)
Get the number of arguments passed to given method invocation, including
the object instance if the call is to an instance method. | | public int | getNumLocals()
Get the number of locals. | | public int | getNumSlots()
Get the number of slots (locals plus stack values). | | public ValueType | getOperand(StackConsumer ins, ConstantPoolGen cpg, int i)
Get the ith operand used by given instruction.
Parameters:
ins - the instruction, which must be a StackConsumer
Parameters:
cpg - the ConstantPoolGen
Parameters:
i - index of operand to get: 0 for the first operand, etc. | | public int | getStackDepth()
Get the depth of the Java operand stack. | | public int | getStackLocation(int loc)
Get a the location in the frame of a value on the operand stack. | | public ValueType | getStackValue(int loc)
Get a value on the operand stack. | | public void | getTopStackWords(ValueType[] valueList)
Get the values on the top of the Java operand stack. | | public ValueType | getTopValue()
Get the value on the top of the Java operand stack. | | public ValueType | getValue(int n)
Get the value at the nth slot. | | public boolean | isBottom()
Return whether or not this object is the special "BOTTOM" value for
Frames. | | public boolean | isTop()
Return whether or not this object the special "TOP" value for Frames. | | public boolean | isValid()
| | public ValueType | popValue()
Pop a value off of the Java operand stack. | | public void | pushValue(ValueType value)
Push a value onto the Java operand stack. | | public boolean | sameAs(Frame<ValueType> other)
Return true if this stack frame is the same as the one given as a
parameter. | | public void | setBottom()
Make this Frame the special "BOTTOM" value. | | public void | setLastUpdateTimestamp(int lastUpdateTimestamp)
| | public void | setTop()
Make this frame the special "TOP" value. | | public void | setValid()
Set the Frame to be valid (neither TOP nor BOTTOM). | | public void | setValue(int n, ValueType value)
Set the value at the nth slot. | | public String | toString()
Convert to string. | | protected String | valueToString(ValueType value)
Subclasses may override this if they want to do something special to
convert Value objects to Strings. |
| Frame | | public Frame(int numLocals)(Code) | | Constructor. This version of the constructor is for subclasses for which
it is always safe to call getDefaultValue(), even when the object is not
fully initialized.
Parameters:
numLocals - number of local variable slots in the method |
| allSlots | | public Collection<ValueType> allSlots()(Code) | | an unmodifiable Collection of the local variable and operand stack slots |
| clearStack | | public void clearStack()(Code) | | Clear the Java operand stack. Only local variable slots will remain in
the frame.
|
| copyFrom | | public void copyFrom(Frame<ValueType> other)(Code) | | Make this Frame exactly the same as the one given as a parameter.
Parameters:
other - the Frame to make this object the same as |
| getArgument | | public ValueType getArgument(InvokeInstruction ins, ConstantPoolGen cpg, int i, int numArguments) throws DataflowAnalysisException(Code) | | Get the ith argument passed to given method invocation.
Parameters:
ins - the method invocation instruction
Parameters:
cpg - the ConstantPoolGen for the class containing the method
Parameters:
i - index of the argument; 0 for the first argument, etc.
Parameters:
numArguments - total number of arguments to the method the ith argument
throws:
DataflowAnalysisException - |
| getArgument | | public ValueType getArgument(InvokeInstruction ins, ConstantPoolGen cpg, int i, SignatureParser sigParser) throws DataflowAnalysisException(Code) | | Get the ith argument passed to given method invocation.
Parameters:
ins - the method invocation instruction
Parameters:
cpg - the ConstantPoolGen for the class containing the method
Parameters:
i - index of the argument; 0 for the first argument, etc. the ith argument
throws:
DataflowAnalysisException - |
| getArgumentSet | | public BitSet getArgumentSet(InvokeInstruction invokeInstruction, ConstantPoolGen cpg, DataflowValueChooser<ValueType> chooser) throws DataflowAnalysisException(Code) | | Get set of arguments passed to a method invocation which match given
predicate.
Parameters:
invokeInstruction - the InvokeInstruction
Parameters:
cpg - the ConstantPoolGen
Parameters:
chooser - predicate to choose which argument values should be in thereturned set BitSet specifying which arguments match the predicate, indexed byargument number (starting from 0)
throws:
DataflowAnalysisException - |
| getArgumentSlot | | public int getArgumentSlot(int i, int numArguments)(Code) | | Get the stack slot that will contain given method argument. Assumes that
this frame is at the location (just before) a method invocation
instruction.
Parameters:
i - the argument index: 0 for first arg, etc.
Parameters:
numArguments - total number of arguments to the called method slot containing the argument value |
| getInstance | | public ValueType getInstance(Instruction ins, ConstantPoolGen cpg) throws DataflowAnalysisException(Code) | | Get the value corresponding to the object instance used in the given
instruction. This relies on the observation that in instructions which
use an object instance (such as getfield, invokevirtual, etc.), the
object instance is the first operand used by the instruction.
Parameters:
ins - the instruction
Parameters:
cpg - the ConstantPoolGen for the method |
| getInstanceSlot | | public int getInstanceSlot(Instruction ins, ConstantPoolGen cpg) throws DataflowAnalysisException(Code) | | Get the slot the object instance referred to by given instruction is
located in.
Parameters:
ins - the Instruction
Parameters:
cpg - the ConstantPoolGen for the method stack slot the object instance is in
throws:
DataflowAnalysisException - |
| getInstanceStackLocation | | public int getInstanceStackLocation(Instruction ins, ConstantPoolGen cpg) throws DataflowAnalysisException(Code) | | Get the stack location (counting down from top of stack, starting at 0)
containing the object instance referred to by given instruction. This
relies on the observation that in instructions which use an object
instance (such as getfield, invokevirtual, etc.), the object instance is
the first operand used by the instruction.
The value returned may be passed to getStackValue(int).
Parameters:
ins - the Instruction
Parameters:
cpg - the ConstantPoolGen for the method stack location (counting down from top of stack, starting at 0)containing the object instance
throws:
DataflowAnalysisException - |
| getLastUpdateTimestamp | | public int getLastUpdateTimestamp()(Code) | | Returns the lastUpdateTimestamp. |
| getNumArguments | | public int getNumArguments(InvokeInstruction ins, ConstantPoolGen cpg) throws DataflowAnalysisException(Code) | | Get the number of arguments passed to given method invocation.
Parameters:
ins - the method invocation instruction
Parameters:
cpg - the ConstantPoolGen for the class containing the method number of arguments; note that this excludes the object instancefor instance methods
throws:
DataflowAnalysisException - |
| getNumArgumentsIncludingObjectInstance | | public int getNumArgumentsIncludingObjectInstance(InvokeInstruction ins, ConstantPoolGen cpg) throws DataflowAnalysisException(Code) | | Get the number of arguments passed to given method invocation, including
the object instance if the call is to an instance method.
Parameters:
ins - the method invocation instruction
Parameters:
cpg - the ConstantPoolGen for the class containing the method number of arguments, including object instance if appropriate
throws:
DataflowAnalysisException - |
| getNumLocals | | public int getNumLocals()(Code) | | Get the number of locals.
|
| getNumSlots | | public int getNumSlots()(Code) | | Get the number of slots (locals plus stack values).
|
| getOperand | | public ValueType getOperand(StackConsumer ins, ConstantPoolGen cpg, int i) throws DataflowAnalysisException(Code) | | Get the ith operand used by given instruction.
Parameters:
ins - the instruction, which must be a StackConsumer
Parameters:
cpg - the ConstantPoolGen
Parameters:
i - index of operand to get: 0 for the first operand, etc. the ith operand used by the given instruction
throws:
DataflowAnalysisException - |
| getStackDepth | | public int getStackDepth()(Code) | | Get the depth of the Java operand stack.
|
| getStackLocation | | public int getStackLocation(int loc) throws DataflowAnalysisException(Code) | | Get a the location in the frame of a value on the operand stack.
Parameters:
loc - the stack location, counting downwards from the top (location0) |
| getStackValue | | public ValueType getStackValue(int loc) throws DataflowAnalysisException(Code) | | Get a value on the operand stack.
Parameters:
loc - the stack location, counting downwards from the top (location0) |
| getTopStackWords | | public void getTopStackWords(ValueType[] valueList) throws DataflowAnalysisException(Code) | | Get the values on the top of the Java operand stack. The top stack item
is placed at the end of the array, so that to restore the values to the
stack, you would push them in the order they appear in the array.
|
| getValue | | public ValueType getValue(int n)(Code) | | Get the value at the nth slot.
Parameters:
n - the slot to get the value of the value in the slot |
| isBottom | | public boolean isBottom()(Code) | | Return whether or not this object is the special "BOTTOM" value for
Frames. Such Frames arise when merging two frames of different size.
|
| isTop | | public boolean isTop()(Code) | | Return whether or not this object the special "TOP" value for Frames.
Such Frames are the identity element of the meet operation.
|
| isValid | | public boolean isValid()(Code) | | Is the frame valid (meaning it is not TOP or BOTTOM)?
|
| pushValue | | public void pushValue(ValueType value)(Code) | | Push a value onto the Java operand stack.
Parameters:
value - the ValueType to push |
| sameAs | | public boolean sameAs(Frame<ValueType> other)(Code) | | Return true if this stack frame is the same as the one given as a
parameter.
Parameters:
other - the other Frame true if the frames are the same, false otherwise |
| setBottom | | public void setBottom()(Code) | | Make this Frame the special "BOTTOM" value. Such Frames arise when
merging two frames of different size.
|
| setLastUpdateTimestamp | | public void setLastUpdateTimestamp(int lastUpdateTimestamp)(Code) | |
Parameters:
lastUpdateTimestamp - The lastUpdateTimestamp to set. |
| setTop | | public void setTop()(Code) | | Make this frame the special "TOP" value. Such Frames are the identity
element of the meet operation.
|
| setValid | | public void setValid()(Code) | | Set the Frame to be valid (neither TOP nor BOTTOM).
|
| setValue | | public void setValue(int n, ValueType value)(Code) | | Set the value at the nth slot.
Parameters:
n - the slot in which to set a new value
Parameters:
value - the value to set |
| valueToString | | protected String valueToString(ValueType value)(Code) | | Subclasses may override this if they want to do something special to
convert Value objects to Strings. By default, we just call toString() on
the values.
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