MicroC is a subset of the language C with the following simplification:

• It supports only integers (int), characters (char) and booleans (bool) as scalar values, array and pointers as compound data types;
• There are no structures, unions, doubles, function pointer;
• No dynamic allocation of memory;
• No multi-dimensional arrays;
• No shorthand for initialize variable during declaration;
• Functions can only return void, int, bool, char;
• No pointer arithmetic;
• Pointers and arrays are not interchangeable;
• no separate compilation, all the code of a program must stay in a unique compilation unit;
• there are only two library functions

void print(int)  // it outputs an integer to standard output
int getint()     // it inputs an integer from standard input 

As part of the exam students will be asked to implement a compiler for MicroC using the OCaml language, the tools and the techniques presented during the course. The project is made of four assignments that are released incrementally during the course, so that students can start working on the project before the end of classes (actually, the last assignment is released in the last lecture).

A description of the provided project kit is here.

The project is split in the following assignments:

• Parsing: this assignment asks students to implement a parser for MicroC. The material is available here;

• Semantic analysis: this assignment mainly concerns the implementation of a static analysis for check that a given program obeys the scoping rule and the type system of the language. The material is available here;

• Code generation: this assignment asks to use the LLVM toolchain to compile a MicroC program to low level code (LLVM bitcode) and to perform some simple optimizations. The material is available here;

• Language extensions: this assignment asks to extend the MicroC language by considering further constructs. In particular, students are required to implement at least three of the following items:

  • floating point arithmetic and strings as in C, i.e. null-terminated arrays of characters;
  • structs, sizeof, bitwise and comma operators;
  • a new semantic analysis pass to detect deadcode;
  • seperate compilation.

• Implemented extensions:

  • pre/post increment/decrement operators, i.e., ++ and --, and abbreviation for assignment operators, i.e., +=, -=, *=, /= and %=;
  • do-while loop, variable declaration with initialization and multiple declarations, e.g., int i = 0, *j = &z;;
  • pointers, arrays & multi-dimensional arrays as in C;

To take the exam students must submit their solutions to the teacher via email by the deadline reported on the exam registration portal. The submitted solution must include the OCaml code, the documentation of the code, and a report describing the design and the implementation choices adopted.

To compile the project remains sufficient to issue in the project root:

$ make

Two scripts are provided:

• microcc.sh: it compiles and links (with the rt-support) a microC program provided as argument
• run_test.sh: it runs all the test cases that are in the dir test/samples. Run it after you've already compiled the project.

Issuing the following will compile the project and execute the test script run_test.sh i.e running all the tests:

$ make test