From 3b1bffdb6bf39ea0e4817aefa9a5cc3167433c4f Mon Sep 17 00:00:00 2001
From: Siraaj Khandkar <siraaj@khandkar.net>
Date: Thu, 22 Aug 2019 15:09:13 -0400
Subject: [PATCH] WIP

---
 compiler/src/lib/tiger/tiger_frame_sig.ml  |  9 ++++++++-
 compiler/src/lib/tiger/tiger_mips_frame.ml | 12 ++++++++++++
 compiler/src/lib/tiger/tiger_translate.ml  | 13 ++++++++++---
 compiler/src/lib/tiger/tiger_translate.mli |  2 ++
 4 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/compiler/src/lib/tiger/tiger_frame_sig.ml b/compiler/src/lib/tiger/tiger_frame_sig.ml
index 2da5d57..5ab7718 100644
--- a/compiler/src/lib/tiger/tiger_frame_sig.ml
+++ b/compiler/src/lib/tiger/tiger_frame_sig.ml
@@ -3,7 +3,11 @@ module type S = sig
 
   type access
 
-  val word_size : int
+  val word_size :
+    int
+
+  val pointer :
+    Tiger_temp.Temp.t
 
   val make :
     name:Tiger_temp.Label.t -> formals:bool list -> t
@@ -16,4 +20,7 @@ module type S = sig
 
   val alloc_local :
     t -> escapes:bool -> access
+
+  val exp :
+    access:access -> pointer:Tiger_tree.exp -> Tiger_tree.exp
 end
diff --git a/compiler/src/lib/tiger/tiger_mips_frame.ml b/compiler/src/lib/tiger/tiger_mips_frame.ml
index 4131702..f373b0e 100644
--- a/compiler/src/lib/tiger/tiger_mips_frame.ml
+++ b/compiler/src/lib/tiger/tiger_mips_frame.ml
@@ -1,6 +1,7 @@
 module List = ListLabels
 
 module Temp = Tiger_temp
+module T    = Tiger_tree
 
 type access =
   | InFrame of {offset_from_frame_pointer : int}
@@ -19,6 +20,8 @@ type t =
   ; instructions : unit  (* TODO: instructions for view shift *)
   }
 
+let pointer = Temp.Temp.gen ()
+
 let word_size_bits  = 32
 let word_size_bytes = word_size_bits / 8
 let word_size       = word_size_bytes
@@ -57,3 +60,12 @@ let make ~name ~formals =
   ; locals_count
   ; instructions = ()  (* TODO: instructions for view shift *)
   }
+
+(*failwith ("NOT IMPLEMENTED: " ^ __MODULE__ ^ ".exp")*)
+
+let exp ~access ~pointer =
+  match access with
+  | InReg {register} ->
+      T.TEMP register
+  | InFrame {offset_from_frame_pointer} ->
+      T.MEM (T.BINOP (T.PLUS, pointer, T.CONST offset_from_frame_pointer))
diff --git a/compiler/src/lib/tiger/tiger_translate.ml b/compiler/src/lib/tiger/tiger_translate.ml
index 483335a..9295df9 100644
--- a/compiler/src/lib/tiger/tiger_translate.ml
+++ b/compiler/src/lib/tiger/tiger_translate.ml
@@ -47,13 +47,13 @@ type exp =
 
 type access =
   (* must know about static links *)
-  { level        : Level.t
-  ; frame_access : Frame.access
+  { level  : Level.t
+  ; access : Frame.access
   }
 
 let alloc_local ~level ~escapes =
   { level
-  ; frame_access = Frame.alloc_local (Level.frame level) ~escapes
+  ; access = Frame.alloc_local (Level.frame level) ~escapes
   }
 
 let formals ~level =
@@ -62,6 +62,9 @@ let formals ~level =
     alloc_local ~level ~escapes
   )
 
+let not_implemented func =
+  failwith (Printf.sprintf "Not implemented: %s.%s" __MODULE__ func)
+
 let rec seq = function
   (* TODO: Is appending 0 OK? How else can the empty case be handled? *)
   | []      -> T.EXP (T.CONST 0)
@@ -100,3 +103,7 @@ let unCx = function
   | Cx g -> g
 
 let dummy__FIXME = Ex (T.CONST 0)
+
+let simple_var {level; access} =
+  let pointer = not_implemented "simple_var frame pointer" in
+  Ex (Frame.exp ~access ~pointer)
diff --git a/compiler/src/lib/tiger/tiger_translate.mli b/compiler/src/lib/tiger/tiger_translate.mli
index ca4b0b2..5250b50 100644
--- a/compiler/src/lib/tiger/tiger_translate.mli
+++ b/compiler/src/lib/tiger/tiger_translate.mli
@@ -24,3 +24,5 @@ val unNx : exp -> Tiger_tree.stm
 val unCx : exp -> gen_stm
 
 val dummy__FIXME : exp  (* FIXME: Remove dummy when real is ready *)
+
+val simple_var : access -> exp
-- 
2.20.1