com.alibaba.fastjson2.internal.asm

Class Frame

java.lang.Object

com.alibaba.fastjson2.internal.asm.Frame

class Frame
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static int	APPEND_FRAME
private static int	ARRAY_OF
private static int	BOOLEAN
private static int	BYTE
private static int	CHAR
(package private) static int	CHOP_FRAME
(package private) static int	CONSTANT_KIND
(package private) static int	DIM_MASK
(package private) static int	DIM_SHIFT
(package private) static int	DIM_SIZE
private static int	DOUBLE
(package private) static int	ELEMENT_OF The constant to be added to an abstract type to get one with one less array dimension.
(package private) static int	FLAGS_SHIFT
(package private) static int	FLAGS_SIZE
private static int	FLOAT
(package private) static int	FULL_FRAME
private int	initializationCount The number of types that are initialized in the basic block.
private int[]	initializations The abstract types that are initialized in the basic block.
private int[]	inputLocals The input stack map frame locals.
(package private) int[]	inputStack The input stack map frame stack.
private static int	INTEGER
(package private) static int	ITEM_ASM_BOOLEAN
(package private) static int	ITEM_ASM_BYTE
(package private) static int	ITEM_ASM_CHAR
(package private) static int	ITEM_ASM_SHORT
(package private) static int	ITEM_DOUBLE
(package private) static int	ITEM_FLOAT
(package private) static int	ITEM_INTEGER
(package private) static int	ITEM_LONG
(package private) static int	ITEM_NULL
(package private) static int	ITEM_OBJECT
(package private) static int	ITEM_TOP
(package private) static int	ITEM_UNINITIALIZED
(package private) static int	ITEM_UNINITIALIZED_THIS
(package private) static int	KIND_MASK
(package private) static int	KIND_SHIFT
(package private) static int	KIND_SIZE
(package private) static int	LOCAL_KIND
private static int	LONG
private static int	NULL
private int[]	outputLocals The output stack map frame locals.
private int[]	outputStack The output stack map frame stack.
private short	outputStackStart The start of the output stack, relatively to the input stack.
private short	outputStackTop The index of the top stack element in outputStack.
(package private) Label	owner The basic block to which these input and output stack map frames correspond.
(package private) static int	REFERENCE_KIND
(package private) static int	SAME_FRAME
(package private) static int	SAME_FRAME_EXTENDED
(package private) static int	SAME_LOCALS_1_STACK_ITEM_FRAME
(package private) static int	SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED
private static int	SHORT
(package private) static int	STACK_KIND
private static int	TOP
private static int	TOP_IF_LONG_OR_DOUBLE_FLAG A flag used for LOCAL_KIND and STACK_KIND abstract types, indicating that if the resolved, concrete type is LONG or DOUBLE, TOP should be used instead (because the value has been partially overridden with an xSTORE instruction).
(package private) static int	UNINITIALIZED_KIND
private static int	UNINITIALIZED_THIS
(package private) static int	VALUE_MASK
(package private) static int	VALUE_SIZE

Constructor Summary

Constructors

Constructor and Description
Frame(Label owner) Constructs a new Frame.

Method Summary

Modifier and Type	Method and Description
(package private) void	accept(MethodWriter methodWriter) Makes the given MethodWriter visit the input frame of this Frame.
private void	addInitializedType(int abstractType) Adds an abstract type to the list of types on which a constructor is invoked in the basic block.
(package private) void	execute(int opcode, int arg, Symbol argSymbol, SymbolTable symbolTable) Simulates the action of the given instruction on the output stack frame.
private static int	getAbstractTypeFromDescriptor(SymbolTable symbolTable, java.lang.String buffer, int offset) Returns the abstract type corresponding to the given type descriptor.
private int	getConcreteOutputType(int abstractOutputType, int numStack) Computes the concrete output type corresponding to a given abstract output type.
private int	getInitializedType(SymbolTable symbolTable, int abstractType) Returns the "initialized" abstract type corresponding to the given abstract type.
private int	getLocal(int localIndex) Returns the abstract type stored at the given local variable index in the output frame.
(package private) boolean	merge(SymbolTable symbolTable, Frame dstFrame)
private static boolean	merge(SymbolTable symbolTable, int sourceType, int[] dstTypes, int dstIndex) Merges the type at the given index in the given abstract type array with the given type.
private int	pop() Pops an abstract type from the output frame stack and returns its value.
private void	pop(int elements) Pops the given number of abstract types from the output frame stack.
private void	pop(java.lang.String descriptor) Pops as many abstract types from the output frame stack as described by the given descriptor.
private void	push(int abstractType) Pushes the given abstract type on the output frame stack.
private void	push(SymbolTable symbolTable, java.lang.String descriptor) Pushes the abstract type corresponding to the given descriptor on the output frame stack.
(package private) void	setInputFrameFromDescriptor(SymbolTable symbolTable, int access, java.lang.String descriptor, int maxLocals) Sets the input frame from the given method description.
private void	setLocal(int localIndex, int abstractType) Replaces the abstract type stored at the given local variable index in the output frame.

Methods inherited from class java.lang.Object

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

Field Detail

SAME_FRAME

static final int SAME_FRAME

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Constant Field Values

SAME_LOCALS_1_STACK_ITEM_FRAME

static final int SAME_LOCALS_1_STACK_ITEM_FRAME

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SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED

static final int SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED

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CHOP_FRAME

static final int CHOP_FRAME

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SAME_FRAME_EXTENDED

static final int SAME_FRAME_EXTENDED

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APPEND_FRAME

static final int APPEND_FRAME

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FULL_FRAME

static final int FULL_FRAME

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ITEM_TOP

static final int ITEM_TOP

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ITEM_INTEGER

static final int ITEM_INTEGER

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ITEM_FLOAT

static final int ITEM_FLOAT

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ITEM_DOUBLE

static final int ITEM_DOUBLE

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ITEM_LONG

static final int ITEM_LONG

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ITEM_NULL

static final int ITEM_NULL

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ITEM_UNINITIALIZED_THIS

static final int ITEM_UNINITIALIZED_THIS

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ITEM_OBJECT

static final int ITEM_OBJECT

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ITEM_UNINITIALIZED

static final int ITEM_UNINITIALIZED

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ITEM_ASM_BOOLEAN

static final int ITEM_ASM_BOOLEAN

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ITEM_ASM_BYTE

static final int ITEM_ASM_BYTE

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ITEM_ASM_CHAR

static final int ITEM_ASM_CHAR

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ITEM_ASM_SHORT

static final int ITEM_ASM_SHORT

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DIM_SIZE

static final int DIM_SIZE

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KIND_SIZE

static final int KIND_SIZE

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FLAGS_SIZE

static final int FLAGS_SIZE

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VALUE_SIZE

static final int VALUE_SIZE

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DIM_SHIFT

static final int DIM_SHIFT

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KIND_SHIFT

static final int KIND_SHIFT

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FLAGS_SHIFT

static final int FLAGS_SHIFT

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DIM_MASK

static final int DIM_MASK

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KIND_MASK

static final int KIND_MASK

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VALUE_MASK

static final int VALUE_MASK

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ARRAY_OF

private static final int ARRAY_OF

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ELEMENT_OF

static final int ELEMENT_OF

The constant to be added to an abstract type to get one with one less array dimension.

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Constant Field Values

CONSTANT_KIND

static final int CONSTANT_KIND

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Constant Field Values

REFERENCE_KIND

static final int REFERENCE_KIND

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Constant Field Values

UNINITIALIZED_KIND

static final int UNINITIALIZED_KIND

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LOCAL_KIND

static final int LOCAL_KIND

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STACK_KIND

static final int STACK_KIND

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TOP_IF_LONG_OR_DOUBLE_FLAG

private static final int TOP_IF_LONG_OR_DOUBLE_FLAG

A flag used for LOCAL_KIND and STACK_KIND abstract types, indicating that if the resolved, concrete type is LONG or DOUBLE, TOP should be used instead (because the value has been partially overridden with an xSTORE instruction).

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Constant Field Values

TOP

private static final int TOP

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BOOLEAN

private static final int BOOLEAN

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BYTE

private static final int BYTE

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CHAR

private static final int CHAR

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SHORT

private static final int SHORT

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INTEGER

private static final int INTEGER

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FLOAT

private static final int FLOAT

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LONG

private static final int LONG

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DOUBLE

private static final int DOUBLE

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NULL

private static final int NULL

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UNINITIALIZED_THIS

private static final int UNINITIALIZED_THIS

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Constant Field Values

owner

final Label owner

The basic block to which these input and output stack map frames correspond.

inputLocals

private int[] inputLocals

The input stack map frame locals. This is an array of abstract types.

inputStack

int[] inputStack

The input stack map frame stack. This is an array of abstract types.

outputLocals

private int[] outputLocals

The output stack map frame locals. This is an array of abstract types.

outputStack

private int[] outputStack

The output stack map frame stack. This is an array of abstract types.

outputStackStart

private short outputStackStart

The start of the output stack, relatively to the input stack. This offset is always negative or null. A null offset means that the output stack must be appended to the input stack. A -n offset means that the first n output stack elements must replace the top n input stack elements, and that the other elements must be appended to the input stack.

outputStackTop

private short outputStackTop

The index of the top stack element in outputStack.

initializationCount

private int initializationCount

The number of types that are initialized in the basic block. See initializations.

initializations

private int[] initializations

The abstract types that are initialized in the basic block. A constructor invocation on an UNINITIALIZED or UNINITIALIZED_THIS abstract type must replace every occurrence of this type in the local variables and in the operand stack. This cannot be done during the first step of the algorithm since, during this step, the local variables and the operand stack types are still abstract. It is therefore necessary to store the abstract types of the constructors which are invoked in the basic block, in order to do this replacement during the second step of the algorithm, where the frames are fully computed. Note that this array can contain abstract types that are relative to the input locals or to the input stack.

Constructor Detail

Frame

Frame(Label owner)

Constructs a new Frame.

Parameters:

owner - the basic block to which these input and output stack map frames correspond.

Method Detail

getAbstractTypeFromDescriptor

private static int getAbstractTypeFromDescriptor(SymbolTable symbolTable,
                                                 java.lang.String buffer,
                                                 int offset)

Returns the abstract type corresponding to the given type descriptor.

Parameters:

symbolTable - the type table to use to lookup and store type Symbol.

buffer - a string ending with a type descriptor.

offset - the start offset of the type descriptor in buffer.

Returns:

the abstract type corresponding to the given type descriptor.

setInputFrameFromDescriptor

final void setInputFrameFromDescriptor(SymbolTable symbolTable,
                                       int access,
                                       java.lang.String descriptor,
                                       int maxLocals)

Sets the input frame from the given method description. This method is used to initialize the first frame of a method, which is implicit (i.e. not stored explicitly in the StackMapTable attribute).

Parameters:

symbolTable - the type table to use to lookup and store type Symbol.

access - the method's access flags.

descriptor - the method descriptor.

maxLocals - the maximum number of local variables of the method.

getLocal

private int getLocal(int localIndex)

Returns the abstract type stored at the given local variable index in the output frame.

Parameters:

localIndex - the index of the local variable whose value must be returned.

Returns:

the abstract type stored at the given local variable index in the output frame.

setLocal

private void setLocal(int localIndex,
                      int abstractType)

Replaces the abstract type stored at the given local variable index in the output frame.

Parameters:

localIndex - the index of the output frame local variable that must be set.

abstractType - the value that must be set.

push

private void push(int abstractType)

Pushes the given abstract type on the output frame stack.

Parameters:

abstractType - an abstract type.

push

private void push(SymbolTable symbolTable,
                  java.lang.String descriptor)

Pushes the abstract type corresponding to the given descriptor on the output frame stack.

Parameters:

symbolTable - the type table to use to lookup and store type Symbol.

descriptor - a type or method descriptor (in which case its return type is pushed).

pop

private int pop()

Pops an abstract type from the output frame stack and returns its value.

Returns:

the abstract type that has been popped from the output frame stack.

pop

private void pop(int elements)

Pops the given number of abstract types from the output frame stack.

Parameters:

elements - the number of abstract types that must be popped.

pop

private void pop(java.lang.String descriptor)

Pops as many abstract types from the output frame stack as described by the given descriptor.

Parameters:

descriptor - a type or method descriptor (in which case its argument types are popped).

addInitializedType

private void addInitializedType(int abstractType)

Adds an abstract type to the list of types on which a constructor is invoked in the basic block.

Parameters:

abstractType - an abstract type on a which a constructor is invoked.

getInitializedType

private int getInitializedType(SymbolTable symbolTable,
                               int abstractType)

Returns the "initialized" abstract type corresponding to the given abstract type.

Parameters:

symbolTable - the type table to use to lookup and store type Symbol.

abstractType - an abstract type.

Returns:

the REFERENCE_KIND abstract type corresponding to abstractType if it is UNINITIALIZED_THIS or an UNINITIALIZED_KIND abstract type for one of the types on which a constructor is invoked in the basic block. Otherwise returns abstractType.

execute

void execute(int opcode,
             int arg,
             Symbol argSymbol,
             SymbolTable symbolTable)

Simulates the action of the given instruction on the output stack frame.

Parameters:

opcode - the opcode of the instruction.

arg - the numeric operand of the instruction, if any.

argSymbol - the Symbol operand of the instruction, if any.

symbolTable - the type table to use to lookup and store type Symbol.

getConcreteOutputType

private int getConcreteOutputType(int abstractOutputType,
                                  int numStack)

Computes the concrete output type corresponding to a given abstract output type.

Parameters:

abstractOutputType - an abstract output type.

numStack - the size of the input stack, used to resolve abstract output types of STACK_KIND kind.

Returns:

the concrete output type corresponding to 'abstractOutputType'.

merge

final boolean merge(SymbolTable symbolTable,
                    Frame dstFrame)

merge

private static boolean merge(SymbolTable symbolTable,
                             int sourceType,
                             int[] dstTypes,
                             int dstIndex)

Merges the type at the given index in the given abstract type array with the given type. Returns true if the type array has been modified by this operation.

Parameters:

symbolTable - the type table to use to lookup and store type Symbol.

sourceType - the abstract type with which the abstract type array element must be merged. This type should be of CONSTANT_KIND, REFERENCE_KIND or UNINITIALIZED_KIND kind, with positive or null array dimensions.

dstTypes - an array of abstract types. These types should be of CONSTANT_KIND, REFERENCE_KIND or UNINITIALIZED_KIND kind, with positive or null array dimensions.

dstIndex - the index of the type that must be merged in dstTypes.

Returns:

true if the type array has been modified by this operation.

accept

final void accept(MethodWriter methodWriter)

Makes the given MethodWriter visit the input frame of this Frame. The visit is done with the MethodWriter.visitFrameStart(int, int, int), MethodWriter.visitAbstractType(int, int) and MethodWriter.visitFrameEnd() methods.

Parameters:

methodWriter - the MethodWriter that should visit the input frame of this Frame.