Setup

In this lab, you continue your work from your solution to Lab 11. So you can continue with the files you have or copy them into a new project and go from there.

However:

• You are not provided with a course solution for the final code generator. Continue working with your Lab 11 code generator and work toward a solution that handles the test files and any extra credit you wish to do.
• The build.xml file will run every test that you place in the TestFiles folder. The test files for the final project can be found in the FinalProjectTestFiles folder.

  When you are ready to test a given feature, just move the corresponding test file from the FinalProjectTestFiles folder into the TestFiles folder.

Notes

• You will no doubt notice some strange notation in the test files for the final project. The method calls and field acccesses are annotated so that you don't have to look in any other source or class files to determine types.

  Java overloads the period symbol in references to methods, statics, and fields. Given

  w.x.y.z we can't tell whether this is some static field z in a class w.x.y, or perhaps y is a static field in class w.x and z is a field of the instance Y

  To simplify matters, the notation for fields and methods is as follows:

  • The period symbol is used only within a class reference. Thus, w.x.y.z is class z in package w.x.y.
  • To reference a static field or method of a class, use two colons (::), so that java.lang.System::out is the System.out output stream.
  • To reference a field of an instance, use ->. Thus, (obj)->a references field a using the reference obj
  • Methods work the same way. To call a static method, use: java.lang.Math::abs(num).
  • All references and methods also include the return type of the result, which appears after a single colon. Thus, the reference above for System.out is really java.lang.System::out : java.io.PrintStream and to print something using println (java.lang.System::out : java.io.PrintStream) -> println : void ("hello") and the absolute value method would be java.lang.Math :: abs : int (num)
• Documentation on the JVM instruction set and Jasmin can be found on the Lab 10 page.
• Unless you are attempting extra credit, CodeGenVisitor.java is the only file you should submit.
• Any extra credit must be arranged with your instructor.

• Your assignment must generate correct object code for the constructs found in the project test files as directed by your instructor. These include expressions, assignment statements, if, while, return, "short-circuiting and", "short-circuiting or", "and", "or", method invocations and declarations.
• One issue you will have to confront is how to handle Boolean-valued expressions. The Java interperter does not have a built-in notion of what a Boolean value is nor how it should be represented.
• Some ideas for extra credit extensions to the compiler are as follows:
  • Pre/post increment/decrement
  • Floating point primitive types
  • Semantic analysis: widening
  • Semantic analysis: coercion to general type
  • Compile == and != into .equals method calls
  • Arrays
  • Extendable primitive types
  • Checking for assignment to "this" -- it's illegal
  • Processing of field declarations -- the .field directive for Jasmin
  • Processing of constructors
  • Accurate declaration for .locals
  • Emitting "short" forms for iload and aload, so that they take
  • Handling "new" and constructor calls one byte instead of two. For example, iload_1 instead of iload 1.

Submitting your project