examples/OCaml-Kaleidoscope/Chapter4/toplevel.ml

   1 (*===----------------------------------------------------------------------===
   2  * Top-Level parsing and JIT Driver
   3  *===----------------------------------------------------------------------===*)
   4
   5 open Llvm
   6 open Llvm_executionengine
   7
   8 (* top ::= definition | external | expression | ';' *)
   9 let rec main_loop the_fpm the_execution_engine stream =
  10   match Stream.peek stream with
  11   | None -> ()
  12
  13   (* ignore top-level semicolons. *)
  14   | Some (Token.Kwd ';') ->
  15       Stream.junk stream;
  16       main_loop the_fpm the_execution_engine stream
  17
  18   | Some token ->
  19       begin
  20         try match token with
  21         | Token.Def ->
  22             let e = Parser.parse_definition stream in
  23             print_endline "parsed a function definition.";
  24             dump_value (Codegen.codegen_func the_fpm e);
  25         | Token.Extern ->
  26             let e = Parser.parse_extern stream in
  27             print_endline "parsed an extern.";
  28             dump_value (Codegen.codegen_proto e);
  29         | _ ->
  30             (* Evaluate a top-level expression into an anonymous function. *)
  31             let e = Parser.parse_toplevel stream in
  32             print_endline "parsed a top-level expr";
  33             let the_function = Codegen.codegen_func the_fpm e in
  34             dump_value the_function;
  35
  36             (* JIT the function, returning a function pointer. *)
  37             let result = ExecutionEngine.run_function the_function [||]
  38               the_execution_engine in
  39
  40             print_string "Evaluated to ";
  41             print_float (GenericValue.as_float Codegen.double_type result);
  42             print_newline ();
  43         with Stream.Error s | Codegen.Error s ->
  44           (* Skip token for error recovery. *)
  45           Stream.junk stream;
  46           print_endline s;
  47       end;
  48       print_string "ready> "; flush stdout;
  49       main_loop the_fpm the_execution_engine stream