From 11f653045aff88fa8f3e09a85415f2b24cdaefc3 Mon Sep 17 00:00:00 2001
From: Paweł Dybiec <pdybiec@stud.cs.uni.wroc.pl>
Date: Sun, 13 Jan 2019 23:54:28 +0100
Subject: Almost working live variable analysis

---
 source/mod_student/live_variables.ml | 73 ++++++++++++++++++++++++++++++++++--
 1 file changed, 70 insertions(+), 3 deletions(-)

diff --git a/source/mod_student/live_variables.ml b/source/mod_student/live_variables.ml
index 580892b..47b7c71 100644
--- a/source/mod_student/live_variables.ml
+++ b/source/mod_student/live_variables.ml
@@ -30,14 +30,81 @@ module Make() = struct
             List.iter set @@ ControlFlowGraph.labels cfg;
             table
 
-
+        let union set list=
+          List.fold_left (fun x y->RegSet.add y x) set list
+          
+        let diff set list =
+          List.fold_left (fun x y->RegSet.remove y x) set list
+          
         let result : LiveVariables.table = initialize_table ()
 
+        let transfer_instr instr input =
+          let output = union (diff input (Ir_utils.defined_registers_instr instr)) (Ir_utils.used_registers_instr instr) in
+          (Knowledge.make ~pre:output ~post:input),instr
+
+          let transfer_terminator t input =
+          let output = union (diff input (Ir_utils.defined_registers_terminator t)) (Ir_utils.used_registers_terminator t) in
+          (Knowledge.make ~pre:output ~post:input),t
+
+          let rec transfer_instr_list instr input = match instr with
+            | [] -> [],input
+            | x::xs -> let ys,input = transfer_instr_list xs input in
+                       let y= transfer_instr x input in
+                       let output = Knowledge.pre (fst y) in
+                       (y::ys,output)
+          
+        let transfer_basic_block l current_knowledge =
+          if l = ControlFlowGraph.exit_label cfg then current_knowledge else
+          if l = ControlFlowGraph.entry_label cfg then current_knowledge else
+          let t = ControlFlowGraph.terminator cfg l in
+          let instr = ControlFlowGraph.block cfg l in
+          let input = BlockKnowledge.post current_knowledge in
+          let t_res = transfer_terminator t input in
+          let input2 = Knowledge.pre @@ fst t_res in
+          let instr_res,output = transfer_instr_list instr input2 in
+          let block = Knowledge.make ~pre:output ~post:input in
+          BlockKnowledge.make_complex ~block ~body:instr_res ~terminator:t_res
+        let changed = ref true
+
+        let update_in label =
+          let input = List.fold_left RegSet.union RegSet.empty
+                        (List.map (fun l -> BlockKnowledge.pre (Hashtbl.find result l))
+                           (ControlFlowGraph.successors cfg label) ) in
+          let old = (Hashtbl.find result label) in
+          let old_input = BlockKnowledge.post old in
+          if input=old_input then () else
+            changed:=true;
+          let new_kn = BlockKnowledge.alter_prepost ~post:input old in
+          Hashtbl.replace result label new_kn
+          
+        let update_ins () =
+          let labels = ControlFlowGraph.labels cfg in
+          List.iter update_in labels
+
+          
+        let update_out label =
+          let old = (Hashtbl.find result label) in
+          let old_input = BlockKnowledge.post old in
+          let new_kn = transfer_basic_block label old in
+          if new_kn=old then () else
+            changed:=true;
+          Hashtbl.replace result label new_kn
+          
+        let update_outs () =
+          let labels = ControlFlowGraph.labels cfg in
+          List.iter update_out labels
+          
         let rec compute_fixpoint () =
-            failwith "Not yet implemented"
+          changed := false;
+          update_ins ();
+            update_outs ();
+            if not !changed then () else
+            compute_fixpoint ()
+          
+                       
 
         let analyse () =
-            compute_fixpoint ();
+          compute_fixpoint ();
             result
 
     end
-- 
cgit 1.4.1