This project was the third homework for the compilers class at Penn. I worked with a partner to implement a compiler for a subset of LLVM (LLVMlite) to x86 in Ocaml. Details about the LLVMlite available here.
Setup instructions for a relatively recent version of Ubuntu (>= 14.04):
sudo apt-get install gcc
sudo apt-get install clang
sudo apt-get install m4 ocaml-native-compilers camlp4-extra opam
opam install menhir
Navigate to the folder and type
make
main.native is the executable that is built. It is setup to run the test harness for the compiler, which are defined by the gradedtests.mll and providedtests.ml files. The test harness compiles llvm programs in the llprograms folder and compares the output of the compiled program with the expected output.
On Linux, run:
main.native -linux --test
On OSX, run:
main.native --test
More details about how to use main.native for testing can be found in README_TESTING.
All of the code that for the compiler is located in the backend.ml file.
To run the compiler on your own LLVM program and then run the generated executable:
let ll_ast = Driver.parse_file path in
let output_path = !Platform.output_path in
let dot_s_file = Platform.gen_name output_path "test" ".s" in
let exec_file = Platform.gen_name output_path "exec" "" in
let asm_ast = Backend.compile_prog ll_ast in
let asm_str = X86.string_of_prog asm_ast in
let _ = Driver.write_file dot_s_file asm_str in
let _ = Platform.link (dot_s_file::c_files) exec_file in
let args = String.concat " " args in
let result = Driver.run_executable args exec_file in
let _ = Platform.sh (Printf.sprintf "rm -f %s %s" dot_s_file exec_file) Platform.ignore_error in
Int64.of_int result
path is a string representing the location of your LLVM file. c_files is an array of strings containing the names of C files with functions that you are calling from your LLVM program. The result of the compilation can be seen in the test.s file.