101 lines
3.5 KiB
OCaml
101 lines
3.5 KiB
OCaml
(*===----------------------------------------------------------------------===
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* Code Generation
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*===----------------------------------------------------------------------===*)
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open Llvm
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exception Error of string
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let context = global_context ()
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let the_module = create_module context "my cool jit"
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let builder = builder context
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let named_values:(string, llvalue) Hashtbl.t = Hashtbl.create 10
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let double_type = double_type context
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let rec codegen_expr = function
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| Ast.Number n -> const_float double_type n
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| Ast.Variable name ->
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(try Hashtbl.find named_values name with
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| Not_found -> raise (Error "unknown variable name"))
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| Ast.Binary (op, lhs, rhs) ->
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let lhs_val = codegen_expr lhs in
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let rhs_val = codegen_expr rhs in
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begin
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match op with
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| '+' -> build_add lhs_val rhs_val "addtmp" builder
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| '-' -> build_sub lhs_val rhs_val "subtmp" builder
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| '*' -> build_mul lhs_val rhs_val "multmp" builder
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| '<' ->
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(* Convert bool 0/1 to double 0.0 or 1.0 *)
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let i = build_fcmp Fcmp.Ult lhs_val rhs_val "cmptmp" builder in
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build_uitofp i double_type "booltmp" builder
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| _ -> raise (Error "invalid binary operator")
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end
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| Ast.Call (callee, args) ->
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(* Look up the name in the module table. *)
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let callee =
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match lookup_function callee the_module with
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| Some callee -> callee
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| None -> raise (Error "unknown function referenced")
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in
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let params = params callee in
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(* If argument mismatch error. *)
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if Array.length params == Array.length args then () else
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raise (Error "incorrect # arguments passed");
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let args = Array.map codegen_expr args in
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build_call callee args "calltmp" builder
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let codegen_proto = function
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| Ast.Prototype (name, args) ->
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(* Make the function type: double(double,double) etc. *)
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let doubles = Array.make (Array.length args) double_type in
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let ft = function_type double_type doubles in
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let f =
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match lookup_function name the_module with
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| None -> declare_function name ft the_module
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(* If 'f' conflicted, there was already something named 'name'. If it
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* has a body, don't allow redefinition or reextern. *)
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| Some f ->
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(* If 'f' already has a body, reject this. *)
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if block_begin f <> At_end f then
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raise (Error "redefinition of function");
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(* If 'f' took a different number of arguments, reject. *)
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if element_type (type_of f) <> ft then
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raise (Error "redefinition of function with different # args");
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f
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in
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(* Set names for all arguments. *)
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Array.iteri (fun i a ->
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let n = args.(i) in
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set_value_name n a;
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Hashtbl.add named_values n a;
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) (params f);
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f
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let codegen_func = function
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| Ast.Function (proto, body) ->
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Hashtbl.clear named_values;
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let the_function = codegen_proto proto in
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(* Create a new basic block to start insertion into. *)
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let bb = append_block context "entry" the_function in
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position_at_end bb builder;
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try
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let ret_val = codegen_expr body in
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(* Finish off the function. *)
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let _ = build_ret ret_val builder in
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(* Validate the generated code, checking for consistency. *)
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Llvm_analysis.assert_valid_function the_function;
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the_function
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with e ->
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delete_function the_function;
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raise e
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