CSF363 Baseline Language

Welcome to CS F363! This is the baseline language project that will be used for all further labs/assignments in this course.

The Base Language

As it is a baseline, the Base language only has arithmetic, variables and a hardcoded dbg(debug) statement. This is how a program in the Base language currently looks like:

let abc = 123 * 20 + (22 / 2) - 3;
dbg abc + abc;

As the course progress, you will be required to make changes to the Base language to fit certain specifications.

Installing requirements

These assignments require a *NIX environment. You can run these commands to install all the software needed to compile this project properly:

For Linux

# the tool used to build this project
sudo apt-get install make
# the tool used for lexing/scanning
sudo apt-get install flex
# the tool used for parsing
sudo apt-get install bison
# the LLVM toolchain
sudo apt-get install clang llvm

For MacOS (Unix)

# install Homebrew if you haven't already
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
# the tool used to build this project
make install
# the tool used for lexing/scanning
brew install flex
# the tool used for parsing
brew install bison
export PATH="$(brew --prefix bison)/bin:$PATH"
# the LLVM toolchain
echo 'export PATH="/usr/local/opt/llvm/bin:$PATH"' >> ~/.bash_profile
source ~/.bash_profile

Running this project

To build this compiler simply run make compiler. You can find the executable called bin/base folder. This is your compiler.

To run this compiler simply run make program. This would use the test.be file and generate an executable of that program called bin/test. This binary is dependent on the runtime/runtime_lib.cc file so make sure it exists.

Directory structure

CSF363-baseline
├── include
│   ├── ast.hh
│   ├── llvmcodegen.hh
│   ├── parser_util.hh
│   └── symbol.hh
├── Makefile
├── README.md
├── runtime
│   └── runtime_lib.cc
├── src
│   ├── ast.cc
│   ├── lexer.lex
│   ├── llvmcodegen.cc
│   ├── main.cc
│   ├── parser.yy
│   └── symbol.cc
└── test.be
│  
└── docs
    ├── lexer.md
    ├── parser.md
    └── llvm.md

The bin folder contains the executable after running make
The include folder contains all header files. All subsequent header files you write must be saved in this folder.
- include/ast.hh contains the definition of the the AST of this language. We have defined one parent class Node as a pure abstract class (similiar to an interface in Java). All types of nodes inherit from this one Node class. By following the definition of the various node types, the tree structure of these ndoes becomes clearer.
- include/llvmcodegen.hh contains the definition of the compiler which emits LLVM-IR code.
- include/parser_util.hh contains the definition of a struct to help bison parse. You will learn more about how bison works as the course progresses.
- symbol.hh contains the definition of rudimentary symbol table. As you add language constructs like scoping and functions, the structure of the symbol table will become more complicated. For now this jst keeps track of the variables that have been declared. The parser uses it ensure variables are not redeclared, and undeclared variables are not used.
The src folder contains the implementation files for the header files. All subsequent implementation files you write mus be saved in this folder.
- src/lexer.lex contains the specification of the scanner. Each token's regex has a subsequent action. In this file, the action is to return the corresponding token that is defined in src/parser.yy at lines 28-31. This file uses the flex lexer generator tool.
- src/parser.yy contains the specification of the parser and the overall grammar of the language. This parser builds an AST as defined in include/ast.hh. This files uses the bison parser generator tool.
- src/main.cc is the main driver file.
The docs contains the in depth explaination of lexer , parser and llvm codegen files .

include/parser.hh is header file that you may think is missing, but it is actually generated by bison with src/bison.yy as input. You should see it in include after running make once.

Additional Reading

common fixes

if make fails or there are some issues , try make clean and then run make again
something that might fix errors if you are writing a seperate lex file: add this line to the beginning:

%option prefix="pr"

This will change yytext -> prtext and will stop name clashes between your new lexer and the lexer.lex

bhargavkulk / CSF363-baseline