DECAF COMPILER

• The repository has been version tagged for ease of understanding

1. Directory structure

• SampleCodes: Contains sample decaf files to test on
• SCANNER-PARSER: Contains parser for semnatic analysis
• AST-CONSTRUCTION: Contains AST generation/Postfix notation in C
• IR-GENERATOR: Contains IR Generation in CPP using C++ API

2. How to run it

• make
• redirect input to the generated executable file(parser)
• To run main code refer to test.sh(flow can be seen there)

3. Description

• The scanner is made using flex. All tokens are put as regular expressions.
• The parser is made using bison. The tokens are passed to it and it looks up the given CFG syntax
• classes are made for taking nodes and making a parse tree
• IR is generated using CPP Api of llvm

4. To implement

• Pointers
• scanf

WHY C and CPP

• I later on found out that C-Api with only structs is very hard to implement.
• Hence I kept the same scanner and parser rules and changed AST to one similar to visitor-cpp

LINKS Referred to

• https://gist.github.com/alloy/d86b007b1b14607a112f
• http://peeterjoot.com/tag/llvm-c-api/
• https://llvm.org/docs/tutorial/LangImpl03.html
• LLVM-documentation for various class methods and datatypes