Add code for lecture 6

Signed-off-by: jmug <u.g.a.mariano@gmail.com>

lec06/code/ir4.ml

@@ -0,0 +1,91 @@
+
+module IR = struct
+  
+  type uid = string     (* Unique identifiers for temporaries. *)
+  type var = string
+  type lbl = string
+  type fn_name = string
+  
+  (* "gensym" -- generate a new unique identifier *)
+  let mk_uid : unit -> uid =
+    let ctr = ref 0 in
+    fun () -> 
+      ctr := !ctr + 1;
+      Printf.sprintf "tmp%d" (!ctr)
+  
+  
+  (* operands *)
+  type opn = 
+    | Id of uid
+    | Const of int64
+
+  (* binary arithmetic operations *)
+  type bop =
+    | Add
+    | Mul
+
+  (* comparison operations *)
+  type cmpop =
+    | Eq
+    | Lt
+  
+  (* instructions *)
+  (* note that there is no nesting of operations! *)
+  type insn =
+    | Let of uid * bop * opn * opn
+    | Load of uid * var
+    | Store of var * opn
+    | ICmp of uid * cmpop * opn * opn
+    | Call of uid * fn_name * (opn list)
+    | Alloca of uid
+  
+  type terminator =
+    | Ret 
+    | Br of lbl                (* unconditional branch *)
+    | Cbr of opn * lbl * lbl   (* conditional branch *)
+
+  (* Basic blocks *)
+  type block = { insns: insn list; terminator: terminator }
+
+  (* Control Flow Graph: a pair of an entry block and a set labeled blocks *)
+  type cfg = block * (lbl * block) list
+
+  (* A function declaration:  (In OCaml syntax: )
+          let f arg1 arg2 arg3 = 
+          let rec entry () = ...
+          and block1 () = ...
+          ...
+          and blockM () = ...
+          in entry ()
+  *)
+  type fdecl = { name: fn_name;  param : uid list; cfg : cfg }
+  
+  type program = {
+    globals : (var * int64) list;
+    fdecls : fdecl list
+  }
+
+  module MLMeaning = struct
+    let add = Int64.add
+    let mul = Int64.mul
+    let load (x : int64 ref) = (!x)
+    let store o (x : int64 ref) = x := o
+    let icmp cmpop x y = cmpop x y 
+
+    let eq (x : int64) (y : int64) = x = y
+    let lt x y = x < y
+
+    let ret x = x
+
+    let cbr cnd lbl1 lbl2 =
+      if cnd then lbl1 () else lbl2 ()
+    let br lbl = lbl ()
+
+    let alloca () = ref 0L
+    let call f x = f x
+  end
+  
+end
+
+
+