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Project 1 (Supporting Simple Operations)

Goal

1. Become familiar with CLEmitter .

2. Extend the base j-- language by adding some basic Java operations (on primitive integers) to the language. Supporting these operations requires studying the j-- compiler in its entirety, if only cursorily, and then making slight modiﬁcations to it.

Grammars

The lexical and syntactic grammars for j-- and Java can be found at https://www.cs.umb.edu/j--/grammar.pdf C.

Download and Test the j-- Compiler

Download and unzip the base j-- compiler C under some directory1 (we’ll refer to this directory as $j). Run the following command inside the $j/j-- directory to compile the j-- compiler.

& ~/workspace/j--

$ ant

Run the following command to compile the j-- program $j/j- the JVM target program HelloWorld .class .

& ~/workspace/j--

$ bash . / bin /j - - tests / jvm / HelloWorld . java

Run the following command to run HelloWorld .class .

-/tests/jvm/HelloWorld.java using the j-

- compiler, which produces

& ~/workspace/j--

$ java HelloWorld

Hello , World

Download the Project Tests

Download and unzip the tests C for this project under $j/j-- .

Problem 1. (Using CLEmitter) Consider the following program IsPrime .java that accepts n (int) as command-line argument, and writes whether or not n is a prime number.

G IsPrime .java

public class IsPrime {

// Entry point .

public static void main ( String [] args ) {

int n = Integer . parseInt ( args [0]);

boolean result = isPrime ( n );

if ( result ) {

System . out . println ( n + " is a prime number " ); } else {

System . out . println ( n + " is not a prime number " );

}

// Returns true if n is prime , and false otherwise .

private static boolean isPrime ( int n ) {

if ( n < 2) {

return false ;

}

for ( int i = 2; i <= n / i ; i ++) {

if ( n % i == 0) {

return false ;

}

return

}

Using the annotated program GenFactorial .java under $j/j--/tests/clemitter as a model, complete the implementation of the program $j/j--/project1/GenIsPrime .java such that it uses the CLEmitter interface to programmatically generate IsPrime .class , ie, the JVM bytecode for the IsPrime .java program listed above.

一 ~/workspace/j--

$ bash . / bin / clemitter project1 / GenIsPrime . java

$ java IsPrime 42

42 is not a prime number $ java IsPrime 31

31 is a prime number

Directions: The bytecode for GenIsPrime .main() is similar to the bytecode for GenFactorial .main() . Here is the pseudocode for the isPrime() method:

if n >= 2 goto A :

return false

A : i = 2

D : if i > n / i goto B :

if n % i != 0 goto C :

return false

C : increment i by 1

goto D :

B : return True

Problem 2. (Arithmetic Operations) Implement the Java arithmetic operators: division / , remainder % , and unary plus + .

AST representations:

❼ JDivideOp in JBinaryExpression .java

❼ JRemainderOp in JBinaryExpression .java

❼ JUnaryPlusOp in JUnaryExpression .java

Semantics:

❼ The LHS and RHS operands of / and % must be ints.

❼ The operand of + must be an int.

一 ~/workspace/j--

$ bash . / bin /j - - project1 / Division . java

$ java Division 60 13

$ bash . / bin /j - - project1 / Remainder . java

$ java Remainder 60 13

$ bash . / bin /j - - project1 / UnaryPlus . java

$ java UnaryPlus 60

Directions:

❼ Deﬁne tokens for / and % in TokenInfo .java .

❼ Modify Scanner .java to scan / and % .

❼ Modify Parser .java to parse / and % , correctly capturing the precedence rules by parsing the operators in the right places.

❼ Implement the analyze() and codegen() methods in JDivideOp , JRemainderOp , and JUnaryPlusOp .

Problem 3. (Bitwise Operations) Implement the Java bitwise operators: unary complement ~ , inclusive or | , exclusive or ^ , and & .

AST representations:

❼ JComplementOp in JUnaryExpression .java

❼ JOrOp in JBinaryExpression .java

❼ JXorOp in JBinaryExpression .java

❼ JAndOp in JBinaryExpression .java

Semantics:

❼ The operand of ~ must be an int.

❼ The LHS and RHS operands of | , ^ , and & must be ints.

一 ~/workspace/j--

$ bash . / bin /j - - project1 / BitwiseNot . java

$ java BitwiseNot 60

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 1 1

$ bash . / bin /j - - project1 / B i t w i s e I n c l u s i v e O r . java

java B i t w i s e I n c l u s i v e O r 60 13

111101

$ bash . / bin /j - - project1 / B i t w i s e E x c l u s i v e O r . java

$ java B i t w i s e E x c l u s i v e O r 60 13

110001

$ bash . / bin /j - - project1 / BitwiseAnd . java

$ java BitwiseAnd 60 13

1100

Directions:

❼ Deﬁne tokens for ~ , | , ^ , and & in TokenInfo .java .

❼ Modify Scanner .java to scan ~ , | , ^ , and & .

❼ Modify Parser .java to parse ~ , | , ^ , and & , capturing the precedence rules by parsing the operators in the right places.

❼ Implement the analyze() and codegen() methods in JComplementOp , JInclusiveOrOp , JExclusiveOrOp , and JAndOp .

Note: there are JVM instructions for | , ^ , and & , but not for ~ , which must be computed as the “exclusive or” of the operand and -1.

Problem 4. (Shift Operations) Implement the Java shift operators: arithmetic left shift << , arithmetic right shift >> , and logical right shift >>> .

AST representations:

❼ JALeftShiftOp in JBinaryExpression .java

❼ JARightShiftOp in JBinaryExpression .java

❼ JLRightShiftOp in JBinaryExpression .java

Semantics:

❼ The LHS and RHS operands of << , >> , and >>> must be ints.

一 ~/workspace/j--

$ bash . / bin /j - - project1 / ALeftShift . java

$ java ALeftShift - 1 16

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

$ bash . / bin /j - - project1 / ARightShift . java

$ java ARightShift - 1 16