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 W. Download and Test the j– Compiler
Download and unzip the base j– compiler W 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.
Run the following command to compile the j– program $j/j–/tests/jvm/HelloWorld.java using the j– compiler, which produces the JVM target program HelloWorld.class.
Run the following command to run HelloWorld.class.
Download the Project Tests
Download and unzip the tests W 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.
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à ~/workspace/j–
$ ant
à ~/workspace/j–
$ bash ./bin/j– tests/jvm/HelloWorld.java
à ~/workspace/j–
$ java HelloWorld Hello , World
Ð 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 true; }
}
1We recommend ~/workspace.
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Project 1 (Supporting Simple Operations)
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.
Directions: The bytecode for GenIsPrime.main() is similar to the bytecode for GenFactorial.main(). Here is the pseudocode for the isPrime() method:
Problem 2. (Arithmetic Operations) Implement the Java arithmetic operators: division /, remainder %, and unary plus +.
AST representations:
• JDivideOp in JBinaryExpression.java
• JRemainderOp in JBinaryExpression.java • JUnaryPlusOp in JUnaryExpression.java
Semantics:
• The LHS and RHS operands of / and % must be ints. • The operand of + must be an int.
à ~/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
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
à ~/workspace/j–
$ bash ./bin/j– project1/Division.java
$ java Division 60 13 4
$ bash ./bin/j– project1/Remainder.java
$ java Remainder 60 13
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$ bash ./bin/j– project1/UnaryPlus.java
$ java UnaryPlus 60 60
Directions:
• Define tokens for / and % in TokenInfo.java.
• Modify Scanner.java to scan / and %.
• Modify Parser.java to parse / and %, correctly capturing the precedence rules by parsing the operators in the right places. • Implement the analyze() and codegen() methods in JDivideOp, JRemainderOp, and JUnaryPlusOp.
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Project 1 (Supporting Simple Operations)
Problem 3. (Bitwise Operations) Implement the Java bitwise operators: unary complement ~, inclusive or |, exclusive or ^, and &.
AST representations:
• JComplementOp in JUnaryExpression.java • JOrOp in JBinaryExpression.java
• JXorOp in JBinaryExpression.java
• JAndOp in JBinaryExpression.java
Semantics:
• The operand of ~ must be an int.
• The LHS and RHS operands of |, ^, and & must be ints.
à ~/workspace/j–
$ bash ./bin/j– project1/BitwiseNot.java
$ java BitwiseNot 60 11111111111111111111111111000011
$ bash ./bin/j– project1/BitwiseInclusiveOr.java
java BitwiseInclusiveOr 60 13 111101
$ bash $ java 110001 $ bash $ java 1100
./bin/j– project1/BitwiseExclusiveOr.java BitwiseExclusiveOr 60 13
./bin/j– project1/BitwiseAnd.java BitwiseAnd 60 13
Directions:
• Define tokens for ~, |, ^, and & in TokenInfo.java.
• Modify Scanner.java to scan ~, |, ^, and &.
• Modify Parser.java to parse ~, |, ^, and &, capturing the precedence rules by parsing the operators in the right places. • 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:
• JALeftShiftOp in JBinaryExpression.java • JARightShiftOp in JBinaryExpression.java • JLRightShiftOp in JBinaryExpression.java
Semantics:
• The LHS and RHS operands of <<, >>, and >>> must be ints.
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Project 1 (Supporting Simple Operations)
à ~/workspace/j–
$ bash ./bin/j– project1/ALeftShift.java $ java ALeftShift -1 16 11111111111111110000000000000000
$ bash ./bin/j– project1/ARightShift.java $ java ARightShift -1 16 11111111111111111111111111111111
$ bash ./bin/j– project1/LRightShift.java $ java LRightShift -1 16
1111111111111111
Directions:
• Define tokens for <<, >>, and >>> in TokenInfo.java.
• Modify Scanner.java to scan <<, >>, and >>>.
• Modify Parser.java to parse <<, >>, and >>>, capturing the precedence rules by parsing the operators in the right places. • Implement the analyze() and codegen() methods in JALeftShiftOp, JARightShiftOp, and JLRightShiftOp.
Before you submit your files, make sure:
• Your code is adequately commented and follows good programming principles.
• You use the template file report.txt for your report. • Your report meets the prescribed guidelines.
Files to submit:
1. GenIsPrime.java 2. TokenInfo.java 3. Scanner.java
4. Parser.java
5. JBinaryExpression.java 6. JUnaryExpression.java 7. report.txt
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