org.objectweb.asm.attrs
public class StackMapAttribute extends Attribute
Note that this implementation does not calculate StackMapFrame structures from the method bytecode. If method code is changed or generated from scratch, then developer is responsible to prepare a correct StackMapFrame structures.
The format of the stack map in the class file is given below. In the following,
stack_map { // attribute StackMap u2 attribute_name_index; u4 attribute_length uoffset number_of_entries; stack_map_frame entries[number_of_entries]; }Each stack map frame has the following format:
stack_map_frame { uoffset offset; ulocalvar number_of_locals; verification_type_info locals[number_of_locals]; ustack number_of_stack_items; verification_type_info stack[number_of_stack_items]; }The verification_type_info structure consists of a one-byte tag followed by zero or more bytes, giving more information about the tag. Each verification_type_info structure specifies the verification type of one or two locations.
union verification_type_info { Top_variable_info; Integer_variable_info; Float_variable_info; Long_variable_info; Double_variable_info; Null_variable_info; UninitializedThis_variable_info; Object_variable_info; Uninitialized_variable_info; } Top_variable_info { u1 tag = ITEM_Top; // 0 } Integer_variable_info { u1 tag = ITEM_Integer; // 1 } Float_variable_info { u1 tag = ITEM_Float; // 2 } Long_variable_info { u1 tag = ITEM_Long; // 4 } Double_variable_info { u1 tag = ITEM_Double; // 3 } Null_variable_info { u1 tag = ITEM_Null; // 5 } UninitializedThis_variable_info { u1 tag = ITEM_UninitializedThis; // 6 } Object_variable_info { u1 tag = ITEM_Object; // 7 u2 cpool_index; } Uninitialized_variable_info { u1 tag = ITEM_Uninitialized // 8 uoffset offset; }
See Also: JSR 139 : Connected
Limited Device Configuration 1.1
Field Summary | |
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List | frames
A List of StackMapFrame instances. |
Constructor Summary | |
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StackMapAttribute() | |
StackMapAttribute(List frames) |
Method Summary | |
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StackMapFrame | getFrame(Label label) |
List | getFrames() |
protected Label[] | getLabels() |
boolean | isCodeAttribute() |
boolean | isUnknown() |
protected Attribute | read(ClassReader cr, int off, int len, char[] buf, int codeOff, Label[] labels) |
String | toString() |
protected ByteVector | write(ClassWriter cw, byte[] code, int len, int maxStack, int maxLocals) |
StackMapFrame
instances.