1 files changed, 34 insertions, 0 deletions
diff --git a/emit.fun b/emit.fun
index c794f26..ada0217 100644
--- a/emit.fun
+++ b/emit.fun
@@ -847,6 +847,36 @@ functor Emit(I: IL) = struct
     List.app (printAllocVar rinfo) toAlloc
   end
 
+  fun getUsedRegs rinfo =
+  let
+    val regs = Array.array (usedRegNum, false)
+
+    fun loop idx =
+      if idx = Array.length rinfo then
+        ()
+      else
+        let
+          val (_, vt) = Array.sub (rinfo, idx)
+        in
+          case vt of
+            VtReg reg => Array.update (regs, reg2idx reg - firstUsedReg, true)
+          | _ => ();
+          loop (idx + 1)
+        end
+    val () = loop 0
+
+    fun collect idx acc =
+      if idx = usedRegNum then
+        acc
+      else
+        if Array.sub (regs, idx) then
+          collect (idx + 1) (idx2reg (idx + firstUsedReg) :: acc)
+        else
+          collect (idx + 1) acc
+  in
+    collect 0 []
+  end
+
   fun regAlloc (F as I.Fi { vregs, ops, paramNum, ... }) =
   let
     val (toAlloc, regInfo) = prepareRegInfo paramNum ops vregs
@@ -858,6 +888,10 @@ functor Emit(I: IL) = struct
 
     val () = linearscan regInfo intervals
     val () = printAlloced regInfo toAlloc
+
+    val usedRegs = getUsedRegs regInfo
+    val () = printfn
+      `"used registers: " Plist preg usedRegs (", ", true, 0) %
   in
     raise Unimplemented
   end