jminusminus

Class CLEmitter

java.lang.Object

jminusminus.CLEmitter

public class CLEmitter
extends Object

This class provides a high level interface for creating (in-memory and file based) representation of Java classes. j-- uses this interface to produce target JVM bytecode from a j-- source program. During the pre-analysis and analysis phases, j-- produces partial (in-memory) classes for the type declarations within the compilation unit, and during the code generation phase, it produces file-based classes for the declarations.

Constructor Summary

Constructors

Constructor and Description
CLEmitter(boolean toFile) Construct a CLEmitter instance.

Method Summary

Methods

Modifier and Type	Method and Description
void	addArrayInstruction(int opcode, String type) Add an array instruction.
void	addBranchInstruction(int opcode, String label) Add a branch instruction.
void	addClass(ArrayList<String> accessFlags, String thisClass, String superClass, ArrayList<String> superInterfaces, boolean isSynthetic) Add a class or interface.
void	addClassAttribute(CLAttributeInfo attribute) Add the specified class attribute to the attribyte section of the class.
void	addCodeAttribute(CLAttributeInfo attribute) Add the specified code attribute to the attribute section of the code for the method last added.
void	addExceptionHandler(String startLabel, String endLabel, String handlerLabel, String catchType) Add an exception handler.
void	addField(ArrayList<String> accessFlags, String name, boolean isSynthetic, double d) Add a double field with initialization.
void	addField(ArrayList<String> accessFlags, String name, boolean isSynthetic, float f) Add a float field with initialization.
void	addField(ArrayList<String> accessFlags, String name, boolean isSynthetic, long l) Add a long field with initialization.
void	addField(ArrayList<String> accessFlags, String name, boolean isSynthetic, String s) Add a String type field with initialization.
void	addField(ArrayList<String> accessFlags, String name, String type, boolean isSynthetic) Add a field without initialization.
void	addField(ArrayList<String> accessFlags, String name, String type, boolean isSynthetic, int i) Add an int, short, char, byte, or boolean field with initialization.
void	addFieldAttribute(CLAttributeInfo attribute) Add the specified field attribute the attribute section of the field last added.
void	addIINCInstruction(int index, int constVal) Add an IINC instruction to increment a variable by a constant.
void	addInnerClass(ArrayList<String> accessFlags, String innerClass, String outerClass, String innerName) Add an inner class.
void	addLabel(String label) Add a jump label to the code section of the method being added.
void	addLDCInstruction(double d) Add an LDC instruction to load a double constant on the operand stack.
void	addLDCInstruction(float f) Add an LDC instruction to load a float constant on the operand stack.
void	addLDCInstruction(int i) Add an LDC instruction to load an int constant on the operand stack.
void	addLDCInstruction(long l) Add an LDC instruction to load a long constant on the operand stack.
void	addLDCInstruction(String s) Add an LDC instruction to load a String constant on the operand stack.
void	addLOOKUPSWITCHInstruction(String defaultLabel, int numPairs, TreeMap<Integer,String> matchLabelPairs) Add a LOOKUPSWITCH instruction -- used for switch statements.
void	addMemberAccessInstruction(int opcode, String target, String name, String type) Add a member (field & method) access instruction.
void	addMethod(ArrayList<String> accessFlags, String name, String descriptor, ArrayList<String> exceptions, boolean isSynthetic) Add a method.
void	addMethodAttribute(CLAttributeInfo attribute) Add the specified method attribute to the attribute section of the method last added.
void	addMULTIANEWARRAYInstruction(String type, int dim) Add a MULTIANEWARRAY instruction for creating multi-dimensional arrays.
void	addNoArgInstruction(int opcode) Add a no argument instruction.
void	addOneArgInstruction(int opcode, int arg) Add a one argument instruction.
void	addReferenceInstruction(int opcode, String type) Add a reference (object) instruction.
void	addTABLESWITCHInstruction(String defaultLabel, int low, int high, ArrayList<String> labels) Add a TABLESWITCH instruction -- used for switch statements.
CLFile	clFile() Return the CLFile instance corresponding to the class built by this emitter.
CLConstantPool	constantPool() Return the constant pool of the class being built.
String	createLabel() Construct and return a unique jump label.
void	destinationDir(String destDir) Set the destination directory for the class file to the specified value.
boolean	errorHasOccurred() Has an emitter error occurred up to now?
static void	initializeByteClassLoader() Set a new ByteClassLoader for loading classes from byte streams.
int	pc() Return the pc (location counter).
Class	toClass() Return the class being constructed as a Java Class instance.
void	write() Write out the class to the file system as a .class file if toFile is true.

Methods inherited from class java.lang.Object

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

Constructor Detail

CLEmitter

public CLEmitter(boolean toFile)

Construct a CLEmitter instance.

Parameters:

toFile - if true, the in-memory representation of the class file will be written to the file system. Otherwise, it won't be saved as a file.

Method Detail

destinationDir

public void destinationDir(String destDir)

Set the destination directory for the class file to the specified value.

Parameters:

destDir - destination directory.

errorHasOccurred

public boolean errorHasOccurred()

Has an emitter error occurred up to now?

Returns:

true or false.

addClass

public void addClass(ArrayList<String> accessFlags,
            String thisClass,
            String superClass,
            ArrayList<String> superInterfaces,
            boolean isSynthetic)

Add a class or interface. This method instantiates a class file representation in memory, so must be called prior to methods that add information (fields, methods, instructions, etc.) to the class.

Parameters:

accessFlags - the access flags for the class or interface.

thisClass - fully qualified name of the class or interface in internal form.

superClass - fully qualified name of the parent class in internal form.

superInterfaces - list of direct super interfaces of this class or interface as fully qualified names in internal form.

isSynthetic - whether the class or interface is synthetic.

addInnerClass

public void addInnerClass(ArrayList<String> accessFlags,
                 String innerClass,
                 String outerClass,
                 String innerName)

Add an inner class. Note that this only registers the inner class with its parent and does not create the class.

Parameters:

accessFlags - access flags for the inner class.

innerClass - fully qualified name of the inner class in internal form.

outerClass - fully qualified name of the outer class in internal form.

innerName - simple name of the inner class.

addField

public void addField(ArrayList<String> accessFlags,
            String name,
            String type,
            boolean isSynthetic)

Add a field without initialization.

Parameters:

accessFlags - access flags for the field.

name - name of the field.

type - type descriptor of the field.

isSynthetic - is this a synthetic field?

addField

public void addField(ArrayList<String> accessFlags,
            String name,
            String type,
            boolean isSynthetic,
            int i)

Add an int, short, char, byte, or boolean field with initialization. If the field is final, the initialization is added to the constant pool. The initializations are all stored as ints, where boolean true and false are 1 and 0 respectively, and short, char, and byte must be cast to int.

Parameters:

accessFlags - access flags for the field.

name - name of the field.

type - type descriptor of the field.

isSynthetic - is this a synthetic field?

i - int value.

addField

public void addField(ArrayList<String> accessFlags,
            String name,
            boolean isSynthetic,
            float f)

Add a float field with initialization. If the field is final, the initialization is added to the constant pool.

Parameters:

accessFlags - access flags for the field.

name - name of the field.

isSynthetic - is this a synthetic field?

f - float value.

addField

public void addField(ArrayList<String> accessFlags,
            String name,
            boolean isSynthetic,
            long l)

Add a long field with initialization. If the field is final, the initialization is added to the constant pool.

Parameters:

accessFlags - access flags for the field.

name - name of the field.

isSynthetic - is this a synthetic field?

l - long value.

addField

public void addField(ArrayList<String> accessFlags,
            String name,
            boolean isSynthetic,
            double d)

Add a double field with initialization. If the field is final, the initialization is added to the constant pool.

Parameters:

accessFlags - access flags for the field.

name - name of the field.

isSynthetic - is this a synthetic field?

d - double value.

addField

public void addField(ArrayList<String> accessFlags,
            String name,
            boolean isSynthetic,
            String s)

Add a String type field with initialization. If the field is final, the initialization is added to the constant pool.

Parameters:

accessFlags - access flags for the field.

name - name of the field.

isSynthetic - is this a synthetic field?

s - String value.

addMethod

public void addMethod(ArrayList<String> accessFlags,
             String name,
             String descriptor,
             ArrayList<String> exceptions,
             boolean isSynthetic)

Add a method. Instructions can subsequently be added to this method using the appropriate methods for adding instructions.

Parameters:

accessFlags - access flags for the method.

name - name of the method.

descriptor - descriptor specifying the return type and the types of the formal parameters of the method.

exceptions - exceptions thrown by the method, each being a name in fully qualified internal form.

isSynthetic - whether this is a synthetic method?

addExceptionHandler

public void addExceptionHandler(String startLabel,
                       String endLabel,
                       String handlerLabel,
                       String catchType)

Add an exception handler.

Parameters:

startLabel - the exception handler is active from the instruction following this label in the code section of the current method being added ...

endLabel - to the instruction following this label. Formally, the handler is active while the program counter is within the interval [startLabel, endLabel).

handlerLabel - the handler begins with instruction following this label.

catchType - the exception type that this exception handler is designated to catch, as a fully qualified name in internal form. If null, this exception handler is called for all exceptions; this is used to immplement "finally".

addNoArgInstruction

public void addNoArgInstruction(int opcode)

Add a no argument instruction. Following instructions can be added using this method:

Arithmetic Instructions:

   IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, 
   LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, 
   DREM, INEG, LNEG, FNEG, DNEG
 

Array Instructions:

   IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, 
   SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, 
   BASTORE, CASTORE, SASTORE, ARRAYLENGTH
 

Bit Instructions:

   ISHL, ISHR, IUSHR, LSHL, LSHR, LUSHR, IOR, LOR, IAND, LAND, 
   IXOR, LXOR
 

Comparison Instructions:

   DCMPG, DCMPL, FCMPG, FCMPL, LCMP
 

Conversion Instructions:

   I2B, I2C, I2S, I2L, I2F, I2D, L2F, L2D, L2I, F2D, F2I, 
   F2L, D2I, D2L, D2F
 

Load Store Instructions:

   ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, LLOAD_0, LLOAD_1, 
   LLOAD_2, LLOAD_3, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, 
   DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, ALOAD_0, ALOAD_1, 
   ALOAD_2, ALOAD_3, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, 
   LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, FSTORE_0, FSTORE_1, 
   FSTORE_2, FSTORE_3, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, 
   ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ICONST_0, ICONST_1, 
   ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, LCONST_0, 
   LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, 
   ACONST_NULL, WIDE (added automatically where necesary)
 

Method Instructions:

   IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN
 

Stack Instructions:

   POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP
 

Miscellaneous Instructions:

   NOP, ATHROW, MONITORENTER, MONITOREXIT
 

The opcodes for instructions are defined in CLConstants class.

Parameters:

opcode - opcode of the instruction.

addOneArgInstruction

public void addOneArgInstruction(int opcode,
                        int arg)

Add a one argument instruction. Wideable instructions are widened if necessary by adding a WIDE instruction before the instruction. Following instructions can be added using this method:

Load Store Instructions:

   ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, 
   DSTORE, ASTORE, BIPUSH, SIPUSH
 

Flow Control Instructions:

 RET
 

The opcodes for instructions are defined in CLConstants class.

Parameters:

opcode - opcode of the instruction.

arg - the argument. For the instructions that deal with local variables, the argument is the local variable index; for BIPUSH and SIPUSH instructions, the argument is the constant byte or short value.

addIINCInstruction

public void addIINCInstruction(int index,
                      int constVal)

Add an IINC instruction to increment a variable by a constant. The instruction is widened if necessary by adding a WIDE instruction before the instruction.

Parameters:

index - local variable index.

constVal - increment value.

addMemberAccessInstruction

public void addMemberAccessInstruction(int opcode,
                              String target,
                              String name,
                              String type)

Add a member (field & method) access instruction. Following instructions can be added using this method:

Field Instructions:

   GETSTATIC, PUTSTATIC, GETFIELD, PUTFIELD
 

Method Instructions:

   INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC, INVOKEINTERFACE, 
   INVOKEDYNAMIC
 

The opcodes for instructions are defined in CLConstants class.

Parameters:

opcode - opcode of the instruction.

target - fully qualified name in internal form of the class to which the member belongs.

name - name of the member.

type - type descriptor of the member.

addReferenceInstruction

public void addReferenceInstruction(int opcode,
                           String type)

Add a reference (object) instruction. Following instructions can be added using this method:

   NEW, CHECKCAST, INSTANCEOF
 

The opcodes for instructions are defined in CLConstants class.

Parameters:

opcode - opcode of the instruction.

type - reference type in internal form.

addArrayInstruction

public void addArrayInstruction(int opcode,
                       String type)

Add an array instruction. Following instructions can be added using this method:

   NEWARRAY, ANEWARRAY
 

The opcodes for instructions are defined in CLConstants class.

Parameters:

opcode - opcode of the instruction.

type - array type. In case of NEWARRAY, the primitive types are specified as: "Z" for boolean, "C" for char, "F" for float, "D" for double, "B" for byte, "S" for short, "I" for int, "J" for long. In case of ANEWARRAY, reference types are specified in internal form.

addMULTIANEWARRAYInstruction

public void addMULTIANEWARRAYInstruction(String type,
                                int dim)

Add a MULTIANEWARRAY instruction for creating multi-dimensional arrays.

Parameters:

type - array type in internal form.

dim - number of dimensions.

addBranchInstruction

public void addBranchInstruction(int opcode,
                        String label)

Add a branch instruction. Following instructions can be added using this method:

   IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, 
   IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, 
   IF_ACMPNE, GOTO, JSR, IF_NULL, IF_NONNULL, GOTO_W, JSR_W
 

The opcodes for instructions are defined in CLConstants class.

Parameters:

opcode - opcode of the instruction.

label - branch label.

addTABLESWITCHInstruction

public void addTABLESWITCHInstruction(String defaultLabel,
                             int low,
                             int high,
                             ArrayList<String> labels)

Add a TABLESWITCH instruction -- used for switch statements.

Parameters:

defaultLabel - jump label for default value.

low - smallest value of index.

high - highest value of index.

labels - list of jump labels for each index value from low to high, end values included.

addLOOKUPSWITCHInstruction

public void addLOOKUPSWITCHInstruction(String defaultLabel,
                              int numPairs,
                              TreeMap<Integer,String> matchLabelPairs)

Add a LOOKUPSWITCH instruction -- used for switch statements.

Parameters:

defaultLabel - jump label for default value.

numPairs - number of pairs in the match table.

matchLabelPairs - key match table.

addLDCInstruction

public void addLDCInstruction(int i)

Add an LDC instruction to load an int constant on the operand stack.

Parameters:

i - int constant.

addLDCInstruction

public void addLDCInstruction(float f)

Add an LDC instruction to load a float constant on the operand stack.

Parameters:

f - float constant.

addLDCInstruction

public void addLDCInstruction(long l)

Add an LDC instruction to load a long constant on the operand stack.

Parameters:

l - long constant.

addLDCInstruction

public void addLDCInstruction(double d)

Add an LDC instruction to load a double constant on the operand stack.

Parameters:

d - double constant.

addLDCInstruction

public void addLDCInstruction(String s)

Add an LDC instruction to load a String constant on the operand stack.

Parameters:

s - String constant.

addClassAttribute

public void addClassAttribute(CLAttributeInfo attribute)

Add the specified class attribute to the attribyte section of the class.

Parameters:

attribute - class attribute.

addMethodAttribute

public void addMethodAttribute(CLAttributeInfo attribute)

Add the specified method attribute to the attribute section of the method last added.

Parameters:

attribute - method attribute.

addFieldAttribute

public void addFieldAttribute(CLAttributeInfo attribute)

Add the specified field attribute the attribute section of the field last added.

Parameters:

attribute - field attribute.

addCodeAttribute

public void addCodeAttribute(CLAttributeInfo attribute)

Add the specified code attribute to the attribute section of the code for the method last added.

Parameters:

attribute - code attribute.

addLabel

public void addLabel(String label)

Add a jump label to the code section of the method being added. A flow control instruction that was added with this label will jump to the instruction right after the label.

Parameters:

label - jump label.

createLabel

public String createLabel()

Construct and return a unique jump label.

Returns:

unique jump label.

pc

public int pc()

Return the pc (location counter). The next instruction will be added with this pc.

Returns:

the pc.

constantPool

public CLConstantPool constantPool()

Return the constant pool of the class being built.

Returns:

constant pool.

initializeByteClassLoader

public static void initializeByteClassLoader()

Set a new ByteClassLoader for loading classes from byte streams.

clFile

public CLFile clFile()

Return the CLFile instance corresponding to the class built by this emitter.

toClass

public Class toClass()

Return the class being constructed as a Java Class instance.

Returns:

Java Class instance.

write

public void write()

Write out the class to the file system as a .class file if toFile is true. The destination directory for the file can be set using the destinationDir(String dir) method.