com.saxonica.ee.bytecode.util

Class Generator

java.lang.Object

org.objectweb.asm.MethodVisitor

org.objectweb.asm.commons.LocalVariablesSorter

org.objectweb.asm.commons.GeneratorAdapter

com.saxonica.ee.bytecode.util.Generator

public class Generator
extends org.objectweb.asm.commons.GeneratorAdapter

This class is an extension of the ASM-supplied GeneratorAdapter library, containing additional utility and shortcut methods for bytecode generation

Field Summary

Fields inherited from class org.objectweb.asm.commons.GeneratorAdapter

ADD, AND, DIV, EQ, GE, GT, LE, LT, MUL, NE, NEG, OR, REM, SHL, SHR, SUB, USHR, XOR

Fields inherited from class org.objectweb.asm.commons.LocalVariablesSorter

firstLocal, nextLocal

Fields inherited from class org.objectweb.asm.MethodVisitor

api, mv

Constructor Summary

Constructors

Constructor and Description
Generator(int access, org.objectweb.asm.commons.Method method, boolean throwsXPathException, org.objectweb.asm.ClassVisitor cv) Create a code generator for a particular method

Method Summary

Methods

Modifier and Type	Method and Description
void	addComment(CompilerService compiler, String message) Add a comment (in the form of an unused label) to the code listing
void	checkClass(Class theClass) Generate a "checking" cast instruction, given a Class the check against.
void	concatenateStrings(int n) Generate code to concatenate a sequence of string objects.
void	getInstanceField(Class theClass, String fieldName) Helper method to get an instance-level field of an object
org.objectweb.asm.Type	getLocalType(int local) Returns the type of the given local variable.
void	getStaticField(Class theClass, String fieldName, Class fieldClass) Helper method to generate code that gets a static field
void	goTo(LabelInfo labelInfo) Generate code to go to a LabelInfo
void	ifCmp(org.objectweb.asm.Type type, int mode, org.objectweb.asm.Label label) Generates the instructions to jump to a label based on the comparison of the top two stack values.
void	ifFalse(LabelInfo label) Generate code to test whether the object on top of stack is NOT an instance of a given class
void	ifInstance(Class theClass, LabelInfo label) Generate code to test whether the object on top of stack is an instance of a given class
void	ifNotInstance(Class theClass, LabelInfo label) Generate code to test whether the object on top of stack is NOT an instance of a given class
void	ifNotSameObject(LabelInfo label) Generate code to test whether the two object references on top of stack refer to different objects
void	ifSameObject(LabelInfo label) Generate code to test whether the two object references on top of stack refer to the same object
void	ifTrue(LabelInfo label) Generate code to test whether the object on top of stack is the boolean true
void	invokeConstructor(Class theClass, Class... argTypes) Helper method to generate code that invokes a constructor.
void	invokeDefaultConstructor(Class theClass) Helper method for a zero-argument constructor.
void	invokeInstanceMethod(Class theClass, String methodName, Class... argTypes) Helper method to generate code that invokes an instance method
void	invokeStaticMethod(Class theClass, String methodName, Class... argTypes) Helper method to generate code that invokes a static method
void	loadArgOrLocal(int slot) Load a local variable or method argument
void	loadLocal(int local) Generates the instruction to load the given local variable on the stack.
void	newInstance(Class theClass) Helper method to generate code that creates a new instance of a class
int	newLocal(Class theClass) Helper method to generate a local bytecode variable
void	pushNull() Push "null" onto the stack
void	showIntVariable(CompilerService compiler, String name, int slot) Generate code to output the value of a run-time variable (which must hold an int)
void	showLongVariable(CompilerService compiler, String name, int slot) Generate code to output the value of a run-time variable (which must hold a long)
void	showMessage(CompilerService compiler, String message) Generate code to output a simple diagnostic message at run-time
void	showObject(CompilerService compiler, String label) Generate code to output the value of of the object on the top of the bytecode stack
void	showObjectVariable(CompilerService compiler, String name, int slot) Generate code to output the value of a run-time bytecode variable (which must hold an object)
void	storeArgOrLocal(int slot) Generate code to store the value from top of stack into a local variable or method argument slot
void	storeLocal(int local) Generates the instruction to store the top stack value in the given local variable.
void	visitTryCatchBlock(LabelInfo start, LabelInfo end, LabelInfo handler, String type) Process a try/catch block

Methods inherited from class org.objectweb.asm.commons.GeneratorAdapter

arrayLength, arrayLoad, arrayStore, box, cast, catchException, checkCast, dup, dup2, dup2X1, dup2X2, dupX1, dupX2, endMethod, getField, getStatic, goTo, ifICmp, ifNonNull, ifNull, ifZCmp, iinc, instanceOf, invokeConstructor, invokeDynamic, invokeInterface, invokeStatic, invokeVirtual, loadArg, loadArgArray, loadArgs, loadArgs, loadLocal, loadThis, mark, mark, math, monitorEnter, monitorExit, newArray, newInstance, newLabel, not, pop, pop2, push, push, push, push, push, push, push, push, putField, putStatic, ret, returnValue, setLocalType, storeArg, storeLocal, swap, swap, tableSwitch, tableSwitch, throwException, throwException, unbox, valueOf

Methods inherited from class org.objectweb.asm.commons.LocalVariablesSorter

newLocal, newLocalMapping, updateNewLocals, visitFrame, visitIincInsn, visitLocalVariable, visitLocalVariableAnnotation, visitMaxs, visitVarInsn

Methods inherited from class org.objectweb.asm.MethodVisitor

visitAnnotation, visitAnnotationDefault, visitAttribute, visitCode, visitEnd, visitFieldInsn, visitInsn, visitInsnAnnotation, visitIntInsn, visitInvokeDynamicInsn, visitJumpInsn, visitLabel, visitLdcInsn, visitLineNumber, visitLookupSwitchInsn, visitMethodInsn, visitMethodInsn, visitMultiANewArrayInsn, visitParameter, visitParameterAnnotation, visitTableSwitchInsn, visitTryCatchAnnotation, visitTryCatchBlock, visitTypeAnnotation, visitTypeInsn

Methods inherited from class java.lang.Object

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

Constructor Detail

Generator

public Generator(int access,
         org.objectweb.asm.commons.Method method,
         boolean throwsXPathException,
         org.objectweb.asm.ClassVisitor cv)

Create a code generator for a particular method

Parameters:

access - the visibility of the method, typically PUBLIC

method - the Method object containing details of the argument and return types

throwsXPathException - true if the method throws XPathException on error

cv - the class visitor for the containing class

Method Detail

ifInstance

public void ifInstance(Class theClass,
              LabelInfo label)

Generate code to test whether the object on top of stack is an instance of a given class

Parameters:

theClass - the class to be tested

label - the label to jump to if the current object is an instance of the class. If it is not an instance, control passes to the next instruction

ifNotInstance

public void ifNotInstance(Class theClass,
                 LabelInfo label)

Generate code to test whether the object on top of stack is NOT an instance of a given class

Parameters:

theClass - the class to be tested

label - the label to jump to if the current object is an instance of the class. If it is not an instance, control passes to the next instruction

goTo

public void goTo(LabelInfo labelInfo)

Generate code to go to a LabelInfo

Parameters:

labelInfo - the label to jump to

pushNull

public void pushNull()

Push "null" onto the stack

ifTrue

public void ifTrue(LabelInfo label)

Generate code to test whether the object on top of stack is the boolean true

Parameters:

label - the label to jump to if the value on top of stack is true (non-zero)

ifFalse

public void ifFalse(LabelInfo label)

Generate code to test whether the object on top of stack is NOT an instance of a given class

Parameters:

label - the label to jump to if the current object is false (zero)

ifSameObject

public void ifSameObject(LabelInfo label)

Generate code to test whether the two object references on top of stack refer to the same object

Parameters:

label - the label to jump to if the two object references are equal

ifNotSameObject

public void ifNotSameObject(LabelInfo label)

Generate code to test whether the two object references on top of stack refer to different objects

Parameters:

label - the label to jump to if the two object references are different

checkClass

public void checkClass(Class theClass)

Generate a "checking" cast instruction, given a Class the check against.

Parameters:

theClass - the class to be tested

addComment

public void addComment(CompilerService compiler,
              String message)

Add a comment (in the form of an unused label) to the code listing

Parameters:

compiler - the compiler service

message - the comment to be added to the code

showMessage

public void showMessage(CompilerService compiler,
               String message)

Generate code to output a simple diagnostic message at run-time

Parameters:

compiler - the compiler service

message - the message to be output at run-time

showObject

public void showObject(CompilerService compiler,
              String label)

Generate code to output the value of of the object on the top of the bytecode stack

Parameters:

compiler - the compiler service

label - a label used to prefix the message to be output at run-time

showObjectVariable

public void showObjectVariable(CompilerService compiler,
                      String name,
                      int slot)

Generate code to output the value of a run-time bytecode variable (which must hold an object)

Parameters:

compiler - the compiler service

name - a label used to prefix the message to be output at run-time, typically the variable name

slot - the slot number on the bytecode stack whose value is to be displayed

showLongVariable

public void showLongVariable(CompilerService compiler,
                    String name,
                    int slot)

Generate code to output the value of a run-time variable (which must hold a long)

Parameters:

compiler - the compiler service

name - a label used to prefix the message to be output at run-time, typically the variable name

slot - the slot number on the bytecode stack whose value is to be displayed

showIntVariable

public void showIntVariable(CompilerService compiler,
                   String name,
                   int slot)

Generate code to output the value of a run-time variable (which must hold an int)

Parameters:

compiler - the compiler service

name - a label used to prefix the message to be output at run-time, typically the variable name

slot - the slot number on the bytecode stack whose value is to be displayed

getStaticField

public void getStaticField(Class theClass,
                  String fieldName,
                  Class fieldClass)

Helper method to generate code that gets a static field

Parameters:

theClass - the class on which the field is defined

fieldName - the name of the field to be fetched

fieldClass - the class of the field to be fetched

invokeStaticMethod

public void invokeStaticMethod(Class theClass,
                      String methodName,
                      Class... argTypes)

Helper method to generate code that invokes a static method

Parameters:

theClass - the class on which the method is defined

methodName - the name of the method to be invoked

argTypes - the classes of the arguments to the method

Throws:

AssertionError - if no suitable method is defined on this class

invokeInstanceMethod

public void invokeInstanceMethod(Class theClass,
                        String methodName,
                        Class... argTypes)

Helper method to generate code that invokes an instance method

Parameters:

theClass - the instance class on which the method is defined

methodName - the name of the method to be invoked

argTypes - the classes of the arguments to the method

Throws:

AssertionError - if no suitable method is defined on this interface

getInstanceField

public void getInstanceField(Class theClass,
                    String fieldName)

Helper method to get an instance-level field of an object

Parameters:

theClass - the instance class on which the method is defined

fieldName - the name of the field to be obtained

Throws:

AssertionError - if no suitable method is defined on this interface

invokeDefaultConstructor

public void invokeDefaultConstructor(Class theClass)

Helper method for a zero-argument constructor. Generates code to invoke the constructor, leaving the constructed instance on the top of the bytecode stack

Parameters:

theClass - the class of object to be constructed

newInstance

public void newInstance(Class theClass)

Helper method to generate code that creates a new instance of a class

Parameters:

theClass - the class to be instantiated

invokeConstructor

public void invokeConstructor(Class theClass,
                     Class... argTypes)

Helper method to generate code that invokes a constructor. Precondition: the target of the method and all its argments are on the stack (the target must first be created using the newInstance() instruction). Postcondition: the above items are removed from the stack

Parameters:

theClass - the class on which the method is defined

argTypes - the classes of the arguments to the constructor

Throws:

AssertionError - if no suitable constructor is defined on this class

newLocal

public int newLocal(Class theClass)

Helper method to generate a local bytecode variable

Parameters:

theClass - the class of the variable

Returns:

the slot number allocated to the variable

loadLocal

public void loadLocal(int local)

Generates the instruction to load the given local variable on the stack.

Overrides:

loadLocal in class org.objectweb.asm.commons.GeneratorAdapter

Parameters:

local - a local variable identifier, as returned by newLocal().

loadArgOrLocal

public void loadArgOrLocal(int slot)

Load a local variable or method argument

Parameters:

slot - the slot number to be loaded, which may represent either a method argument or a local variable

storeLocal

public void storeLocal(int local)

Generates the instruction to store the top stack value in the given local variable.

Overrides:

storeLocal in class org.objectweb.asm.commons.GeneratorAdapter

Parameters:

local - a local variable identifier, as returned by newLocal().

storeArgOrLocal

public void storeArgOrLocal(int slot)

Generate code to store the value from top of stack into a local variable or method argument slot

Parameters:

slot - the slot number to be used, which may represent either a method argument or a local variable

getLocalType

public org.objectweb.asm.Type getLocalType(int local)

Returns the type of the given local variable.

Overrides:

getLocalType in class org.objectweb.asm.commons.GeneratorAdapter

Parameters:

local - a local variable identifier, as returned by newLocal().

Returns:

the type of the given local variable.

visitTryCatchBlock

public void visitTryCatchBlock(LabelInfo start,
                      LabelInfo end,
                      LabelInfo handler,
                      String type)

Process a try/catch block

Parameters:

start - the label for the start of the try block

end - the label for the end of the try block

handler - the label for the catch block

type - the type

concatenateStrings

public void concatenateStrings(int n)

Generate code to concatenate a sequence of string objects. The strings must be on the stack, in order. On completion, the concatenated string is on the top of the bytecode stack

Parameters:

n - the number of strings to be concatenated

ifCmp

public void ifCmp(org.objectweb.asm.Type type,
         int mode,
         org.objectweb.asm.Label label)

Generates the instructions to jump to a label based on the comparison of the top two stack values.

This method overrides the corresponding method in class GeneratorAdaptor in order to fix bug 1564

Overrides:

ifCmp in class org.objectweb.asm.commons.GeneratorAdapter

Parameters:

type - the type of the top two stack values.

mode - how these values must be compared. One of EQ, NE, LT, GE, GT, LE.

label - where to jump if the comparison result is true.