llvm-project/llvm/examples/OCaml-Kaleidoscope/Chapter4/toplevel.ml

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(*===----------------------------------------------------------------------===
* Top-Level parsing and JIT Driver
*===----------------------------------------------------------------------===*)
open Llvm
open Llvm_executionengine
(* top ::= definition | external | expression | ';' *)
let rec main_loop the_fpm the_execution_engine stream =
match Stream.peek stream with
| None -> ()
(* ignore top-level semicolons. *)
| Some (Token.Kwd ';') ->
Stream.junk stream;
main_loop the_fpm the_execution_engine stream
| Some token ->
begin
try match token with
| Token.Def ->
let e = Parser.parse_definition stream in
print_endline "parsed a function definition.";
dump_value (Codegen.codegen_func the_fpm e);
| Token.Extern ->
let e = Parser.parse_extern stream in
print_endline "parsed an extern.";
dump_value (Codegen.codegen_proto e);
| _ ->
(* Evaluate a top-level expression into an anonymous function. *)
let e = Parser.parse_toplevel stream in
print_endline "parsed a top-level expr";
let the_function = Codegen.codegen_func the_fpm e in
dump_value the_function;
(* JIT the function, returning a function pointer. *)
let result = ExecutionEngine.run_function the_function [||]
the_execution_engine in
print_string "Evaluated to ";
print_float (GenericValue.as_float Codegen.double_type result);
print_newline ();
with Stream.Error s | Codegen.Error s ->
(* Skip token for error recovery. *)
Stream.junk stream;
print_endline s;
end;
print_string "ready> "; flush stdout;
main_loop the_fpm the_execution_engine stream