I'm trying to build a parser for Promela in llvm. I have the parser SPIN uses, which is built using yacc, including the input that goes to yacc. Is there a way to use the yacc parser to quickly and painlessly generate a clang/llvm parser? I will be using it to generate call graphs and perform static analysis.
What I need to know now is whether I can use the existing Promela compiler, which was built with yacc, to quickly build a parser (and later, IR generator) using the llvm framework.
Yes, you can re-use the existing YACC-grammar (and if you want even the existing AST) for your project. "Building a parser using the llvm framework" is a bit misleading though because LLVM won't have anything to do with parsing and the AST. LLVM won't enter into it until you generate the LLVM IR and then work with it.
So you either take the existing YACC grammar and the existing AST or you only take the grammar and replace the actions with ones that create your own AST that you've defined yourself. Either way that part won't involve LLVM.
Then you'd write a separate phase that walks the AST and generates LLVM IR using the LLVM API, on which you can then run all the transformations and analyses supported by LLVM.