scale.j2s
Class Java2Scribble

java.lang.Object
  scale.j2s.Java2Scribble

public class Java2Scribble
extends java.lang.Object

This class maintains the global (inter-class) information used while converting Java byte codes to Scribble.

$Id: Java2Scribble.java,v 1.29 2007-10-04 19:58:13 burrill Exp $

Copyright 2008 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Field Summary

static int	ARRAYTYPE
static IntegerType	byteType The Scale representation for the Java byte type.
static PointerType	cCharpType The Scale representation for a pointer to the Java char type.
static PointerType	charpType The Scale representation for a pointer to the Java char type.
static CharacterType	charType The Scale representation for the Java char type.
static int	CLASSTYPE
ProcedureDecl	createStringProc A procedure that constructs a String from an array of shorts.
static FloatType	doubleType The Scale representation for the Java double type.
ProcedureDecl	findIntMethodProc A procedure that finds the address of an interface method.
FloatLiteral	float0 The literal for 0.0.
FloatLiteral	float1 The literal for 1.0.
FloatLiteral	float2 The literal for 2.0.
static FloatType	floatType The Scale representation for the Java float type.
VariableDecl	globalExceptionVariable The global exception variable.
ProcedureDecl	instanceOfProc A procedure that checks if a is an instance of b
IntLiteral	int0 The literal for 0.
IntLiteral	int1 The literal for 1.
IntLiteral	int2 The literal for 2.
IntLiteral	int3 The literal for 3.
IntLiteral	int4 The literal for 4.
IntLiteral	int5 The literal for 5.
static int	INTERFACETYPE
IntLiteral	intm1 The literal for -1.
static PointerType	intpType The Scale representation for a pointer to the Java int type.
static IntegerType	intType The Scale representation for the Java int type.
static IntegerType	longType The Scale representation for the Java long type.
ProcedureDecl	lookupExceptionProc A procedure that maps an exception to an index into the methods exception table.
ProcedureDecl	makeExceptionProc A procedure that creates an exception.
IntLiteral	nil The literal for null.
static IntegerType	shortType The Scale representation for the Java short type.
Type	stringpType Of type pointer to the String class.
static Type[]	typeMap Map from Java type specifier (int) to the Scale type.
static PointerType	voidp The Scale representation for the unspecified pointer type.

Constructor Summary

Java2Scribble()

Method Summary

void	addTopGlobal(Declaration d) Specify that the Declaration is a top level declaration so that it is processed by Clef2C later.
static void	cleanup() Clean up for profiling statistics.
void	convertClass(ClassStuff cs, CallGraph cg)
ProcedureType	createMethodType(Type ct, java.lang.String descriptor, boolean isStatic) Return a Clef ProcedureType for the method.
void	defineFunctions() Create the Declarations for various runtime procedures needed.
void	defineStructures() Each class has a virtual function transfer vector (vtable) associated with it.
FieldDecl	findField(ClassStuff cs, java.lang.String fname) Return the named FieldDecl in the structure.
java.lang.String	genMethodName(java.lang.String className, java.lang.String mName, java.lang.String descriptor) Return the fully qualified name of a method.
Accessibility	getAccess(int accessFlags) Convert from Java method access specifier to Scale access specifier.
FieldDecl	getArrayField(java.lang.String fname) Return the named FieldDecl in the array structure.
Type	getArrayHeaderType() Return the generic array structure type.
Type	getArrayType(int type) Return the array type for the specified Java type.
ClassStuff	getClass(java.lang.String cname) Return the class information for the specified class.
VariableDecl	getClassDecl(ClassStuff ecs) Return the variable defining the class' CLASSENTRY.
VariableDecl	getClassDecl(java.lang.String name) Return the variable defining the class' CLASSENTRY.
java.util.Enumeration<ClassStuff>	getClasses() Return an enumeration of all the classes.
Vector<Type>	getClefTypes(java.lang.String descriptor) Return a vector of AST Types corresponding the the types specified in the descriptor.
Declaration	getGlobal(java.lang.String name) Return the top level Declaration for the specified name.
VariableDecl	getGlobalVar(ClassStuff cs, java.lang.String fname) Return the VariableDecl for the static field of a Java class.
Literal	getIntLiteral(int value) Return return a Clef Literal with the specified value.
java.lang.Object	getLiteral(ClassFile cf, int index) Return the Clef Literal for the specified constant value.
ProcedureDecl	getProcedureDecl(Type ct, java.lang.String name, java.lang.String descriptor, boolean isStatic) Create a Clef ProcedureDecl for the specified method.
java.util.Enumeration<Declaration>	getTopDecls() Return the special top level Declarations.
int	getTypeSpecifier(Type type) Return the Java type specifier for the Scale type.
VariableDecl	getVTableDecl(ClassStuff cs) Return the virtual table VariableDecl for the class.
FieldDecl	getVTableField(java.lang.String fname) Return the named FieldDecl in the virtual table structure.
VariableDecl	makeExceptionTable(ClassFile cf, java.lang.String methodName, ExceptionEntry[] entries) Create the run time exception table for a class' method.
VariableDecl	makeStringInit(java.lang.String s) This method creates the Clef representation of a Java String as an array of shorts.

Methods inherited from class java.lang.Object

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

Field Detail

CLASSTYPE

public static final int CLASSTYPE

See Also:

Constant Field Values

INTERFACETYPE

public static final int INTERFACETYPE

See Also:

Constant Field Values

ARRAYTYPE

public static final int ARRAYTYPE

See Also:

Constant Field Values

byteType

public static final IntegerType byteType

The Scale representation for the Java byte type.

shortType

public static final IntegerType shortType

The Scale representation for the Java short type.

intType

public static final IntegerType intType

The Scale representation for the Java int type.

longType

public static final IntegerType longType

The Scale representation for the Java long type.

floatType

public static final FloatType floatType

The Scale representation for the Java float type.

doubleType

public static final FloatType doubleType

The Scale representation for the Java double type.

charType

public static final CharacterType charType

The Scale representation for the Java char type.

charpType

public static final PointerType charpType

The Scale representation for a pointer to the Java char type.

cCharpType

public static final PointerType cCharpType

The Scale representation for a pointer to the Java char type.

intpType

public static final PointerType intpType

The Scale representation for a pointer to the Java int type.

voidp

public static final PointerType voidp

The Scale representation for the unspecified pointer type.

typeMap

public static final Type[] typeMap

Map from Java type specifier (int) to the Scale type.

createStringProc

public ProcedureDecl createStringProc

A procedure that constructs a String from an array of shorts.

stringpType

public Type stringpType

Of type pointer to the String class.

findIntMethodProc

public ProcedureDecl findIntMethodProc

A procedure that finds the address of an interface method.

makeExceptionProc

public ProcedureDecl makeExceptionProc

A procedure that creates an exception.

lookupExceptionProc

public ProcedureDecl lookupExceptionProc

A procedure that maps an exception to an index into the methods exception table.

instanceOfProc

public ProcedureDecl instanceOfProc

A procedure that checks if a is an instance of b

globalExceptionVariable

public VariableDecl globalExceptionVariable

The global exception variable. This variable is checked after each method call. If it is non-null, an exception has occured.

intm1

public final IntLiteral intm1

The literal for -1.

int0

public final IntLiteral int0

The literal for 0.

int1

public final IntLiteral int1

The literal for 1.

int2

public final IntLiteral int2

The literal for 2.

int3

public final IntLiteral int3

The literal for 3.

int4

public final IntLiteral int4

The literal for 4.

int5

public final IntLiteral int5

The literal for 5.

float0

public final FloatLiteral float0

The literal for 0.0.

float1

public final FloatLiteral float1

The literal for 1.0.

float2

public final FloatLiteral float2

The literal for 2.0.

nil

public final IntLiteral nil

The literal for null.

Constructor Detail

Java2Scribble

public Java2Scribble()

Method Detail

convertClass

public void convertClass(ClassStuff cs,
                         CallGraph cg)

getTypeSpecifier

public int getTypeSpecifier(Type type)

Return the Java type specifier for the Scale type. Index 0 is used for all address types.

getClasses

public java.util.Enumeration<ClassStuff> getClasses()

Return an enumeration of all the classes.

See Also:

ClassStuff

getGlobal

public Declaration getGlobal(java.lang.String name)

Return the top level Declaration for the specified name.

getClass

public ClassStuff getClass(java.lang.String cname)

Return the class information for the specified class.

Parameters:

cname - is the name of the class

getAccess

public Accessibility getAccess(int accessFlags)

Convert from Java method access specifier to Scale access specifier.

getGlobalVar

public VariableDecl getGlobalVar(ClassStuff cs,
                                 java.lang.String fname)

Return the VariableDecl for the static field of a Java class.

Parameters:

cs - specifies the class with the static field

fname - is the name of the field

addTopGlobal

public void addTopGlobal(Declaration d)

Specify that the Declaration is a top level declaration so that it is processed by Clef2C later.

getTopDecls

public java.util.Enumeration<Declaration> getTopDecls()

Return the special top level Declarations.

defineStructures

public void defineStructures()

Each class has a virtual function transfer vector (vtable) associated with it. Each class instance has a pointer to this vector. Thus, the instance address can be used to access the transfer vector to obtain the address of a class method. The transfer vector contains addresses only for public or protected, non-static methods.

The structure of the vtable is as follows:

 struct VTABLE {
   const CLASS    *class;          // The class structure for this class
   int             interfaceCount; // The number of interfaces implemented by this class
   INTERFACEENTRY *interfaces;     // A list of the interfaces implemented by this class
   void           *methods[0]      // The addresses of the virtual methods - there is at least one.
 };
 
 Each INTERFACEENTRY records a different interface:
 
 struct INTERFACEENTRY {
   int          hash;             // A hash of the interface name
   const CLASS *class;            // The class structure for this interface
   void        *((methods *)[0]); // A pointer to a table of method addresses
 } ;
 
 The CLASS structure is defined as
 
 struct CLASS {
   const unsigned short *name;
   const struct CLASS   *super;
   byte           kind;
 };
 
 Note - all the addresses that occur in the array pointed to by
 the methods field are also in the VTABLE instance for the class.

defineFunctions

public void defineFunctions()

Create the Declarations for various runtime procedures needed.

getClassDecl

public VariableDecl getClassDecl(java.lang.String name)

Return the variable defining the class' CLASSENTRY.

Parameters:

name - is the name of the class

getClassDecl

public VariableDecl getClassDecl(ClassStuff ecs)

Return the variable defining the class' CLASSENTRY.

Parameters:

ecs - is the ClassStuff for the class

getArrayType

public Type getArrayType(int type)

Return the array type for the specified Java type.

Parameters:

type - is the Java type

See Also:

CodeAttribute

getClefTypes

public Vector<Type> getClefTypes(java.lang.String descriptor)

Return a vector of AST Types corresponding the the types specified in the descriptor.

See Also:

Type

genMethodName

public java.lang.String genMethodName(java.lang.String className,
                                      java.lang.String mName,
                                      java.lang.String descriptor)

Return the fully qualified name of a method.

Parameters:

className - is the name of the method's class

mName - is the name of the method

descriptor - is the Java method descriptor

makeStringInit

public VariableDecl makeStringInit(java.lang.String s)

This method creates the Clef representation of a Java String as an array of shorts. The first element of the array is the length of the string.

Returns:

a Clef VariableDecl for the String

makeExceptionTable

public VariableDecl makeExceptionTable(ClassFile cf,
                                       java.lang.String methodName,
                                       ExceptionEntry[] entries)

Create the run time exception table for a class' method.

Parameters:

cf - is the ClassFile for the class

methodName - is the name of the method

entries - is the table of exception handlers

getLiteral

public java.lang.Object getLiteral(ClassFile cf,
                                   int index)

Return the Clef Literal for the specified constant value.

Parameters:

cf - is the class file containing the constant

index - is the index of the constant in the constant pool

getIntLiteral

public Literal getIntLiteral(int value)

Return return a Clef Literal with the specified value.

createMethodType

public ProcedureType createMethodType(Type ct,
                                      java.lang.String descriptor,
                                      boolean isStatic)

Return a Clef ProcedureType for the method.

Parameters:

ct - is the type of the 'this' parameter

descriptor - is the Java method descriptor

getProcedureDecl

public ProcedureDecl getProcedureDecl(Type ct,
                                      java.lang.String name,
                                      java.lang.String descriptor,
                                      boolean isStatic)

Create a Clef ProcedureDecl for the specified method.

Parameters:

ct - is the type of the 'this' parameter

name - is the name of the method

descriptor - is the Java method descriptor

Returns:

a new ProcedureDecl

findField

public FieldDecl findField(ClassStuff cs,
                           java.lang.String fname)

Return the named FieldDecl in the structure.

Parameters:

cs - specifies the class

fname - specifies the name of the field

getArrayField

public FieldDecl getArrayField(java.lang.String fname)

Return the named FieldDecl in the array structure.

getVTableField

public FieldDecl getVTableField(java.lang.String fname)

Return the named FieldDecl in the virtual table structure.

getVTableDecl

public VariableDecl getVTableDecl(ClassStuff cs)

Return the virtual table VariableDecl for the class.

getArrayHeaderType

public Type getArrayHeaderType()

Return the generic array structure type.

cleanup

public static void cleanup()

Clean up for profiling statistics.