Rascal

Rascal is an LLVM-based compiler written in Rust for a small subset of Pascal with full debug support.

Rascal has been written with focus on learning Rust and generation of debug information with LLVM. So far, little effort has been spent to make it work on multiple platforms, be easy to build or be easy to use.

Currently Rascal works only on Linux x86_64.

Requirements:

• Rust built from the HEAD of the master branch, in particular:
  • the compiler: rustc
  • LLVM bindings module: $RUST_DIR/src/librustc/lib/llvm.rs
  • LLVM library for Rust: $RUST_DIR/rustllvm/x86_64-unknown-linux-gnu/librustllvm.so
  • LLVM target code generation tool llc that is built together with Rust: $RUST_DIR/llvm/x86_64-unknown-linux-gnu/$BUILD_TYPE/llc (where $BUILD_TYPE is the type of LLVM build process, eg. Release+Asserts)

Building

Steps:

1. Copy Makefile.in to Makefile.
2. Fill Makefile with your path to the directory with the LLVM library for Rust (librustllvm.so).
3. Copy rascal.rc.in to rascal.rc.
4. Fill rascal.rc with your path to the LLVM bindings module (llvm.rs).
5. Run make.

Running

Steps:

1. Modify LD_LIBRARY_PATH environment variable to contain the directory with the LLVM library for Rust (librustllvm.so).
2. Run rascal <file>.pas. It will produce <file>.bc containing LLVM bitcode with full debug information.
3. Run llc <file>.bc. It will produce <file>.s with the assembly code.
4. Run gcc -g <file>.s runtime.c (alternatively clang may be used) to generate the executable with full debug information.
   • runtime.c is the "standard library" of Rascal.

The steps 2-4 can be executed at once using the compile.sh script.

Notes on debugging executables produced by Rascal

1. All identifiers are lower cased (Pacal is case-insensitive).
2. The main block of a program is compiled as the main() function.

License

Rascal is distributed under the terms of the MIT License. See LICENSE file for details.