Add strings to the IR

[snipe.git] / codegen / solidify.sml

(* L3 Compiler
 * Takes a list of mappings of temporaries to colors and a pseudoasm listing,
 * then produces x86 code.
 * Author: Chris Lu <czl@andrew.cmu.edu>
 * Author: Joshua Wise <jwise@andrew.cmu.edu>
 *)

signature SOLIDIFY =
sig
  type colorings = (Temp.temp * int) list
  type asm = Blarg.insn list
  
  val solidify : colorings -> asm -> asm
end

structure Solidify :> SOLIDIFY =
struct
  structure X = Blarg
  structure T = Temp
  
  type colorings = (Temp.temp * int) list
  type asm = Blarg.insn list
  
  exception Spilled

  structure TempMap = SplayMapFn(struct
                                   type ord_key = Temp.temp
                                   val compare = Temp.compare
                                 end)
  structure Tm = Temp

  fun solidify (regmap : colorings) (instrs : asm) : asm =
    let
      (* r11 and r12 is reserved for spilling *)
      val maxreg = X.regtonum X.R10
      fun numtoreg n =
          if (n > maxreg)
          then raise Spilled
          else X.numtoreg n

      val tempnums = List.foldr (fn ((t,n),b) => TempMap.insert(b,t,n)) (TempMap.empty) regmap
      fun temptonum (t: T.temp) : int = valOf (TempMap.find (tempnums, t))

      fun temptoreg (t: T.temp) : Blarg.reg =
        numtoreg (temptonum t)          
        handle Option => raise ErrorMsg.InternalError ("Uncolored temp "^(Temp.name t)^", agh!")

      val spillreg1 = X.R12
      val spillreg2 = X.R11

      (* Determine which need to be saved. *)
      val opsused = (map (fn (_, n) => X.REG (numtoreg n handle Spilled => X.R12)) regmap) @ [X.REG X.R11]
      val saveregs = X.OperSet.intersection (
        X.OperSet.addList (X.OperSet.empty, opsused),
        X.OperSet.addList (
          X.OperSet.empty,
          [X.REG X.R7,
           X.REG X.R8,
           X.REG X.R9,
           X.REG X.R10,
           X.REG X.R11,
           X.REG X.R12]))
      val savelist = X.OperSet.listItems saveregs
      val nsave = length savelist

      val numreg = foldr (Int.max) 0 (map (fn (_, n) => n) regmap)    (* Number of registers used. *)
      val nspilled = Int.max (numreg - maxreg, 0)    (* Number of spilled registers. *)
      fun isspilled (X.TEMP temp) = (temptonum temp) > maxreg    (* Whether a register is spilled *)
        | isspilled (X.STACKARG _) = true
        | isspilled _ = false

      val stacksz = (nspilled + nsave) * 1
      fun stackpos (reg: int) = stacksz - (reg - maxreg + nsave) * 1    (* Stack position of some register number *)

      val prologue =
        [X.INSN (X.AL, X.MOVLIT (X.REG X.R4, Word.fromInt stacksz)),
         X.INSN (X.AL, X.SUB (X.REG X.SP, X.REG X.R4))] @
        (List.concat
          (ListPair.map
            (fn (num, reg) =>
              [X.INSN (X.AL, X.MOVLIT (X.REG X.R4, Word.fromInt (stacksz - 1*(num+1)))),
               X.INSN (X.AL, X.ADD (X.REG X.R4, X.REG X.SP)),
               X.INSN (X.AL, X.STO (X.REG X.R4, reg))])
            (List.tabulate (nsave, fn x => x), savelist)
          )
        )
      val epilogue =
        (List.concat
          (ListPair.map
            (fn (num, reg) =>
              [X.INSN (X.AL, X.MOVLIT (X.REG X.R4, Word.fromInt (stacksz - 1*(num+1)))),
               X.INSN (X.AL, X.ADD (X.REG X.R4, X.REG X.SP)),
               X.INSN (X.AL, X.LDR (reg, X.REG X.R4))])
            (List.tabulate (nsave, fn x => x), savelist)
          )
        ) @
        [X.INSN (X.AL, X.MOVLIT (X.REG X.R4, Word.fromInt stacksz)),
         X.INSN (X.AL, X.ADD (X.REG X.SP, X.REG X.R4))]
      val endlbl = Label.new()

      fun spill (X.TEMP temp, xreg: Blarg.reg) =    (* Spill a register if need be. *)
            let
              val base = X.REG X.SP
              val offs = Word.fromInt (stackpos (temptonum temp))
            in
              if (isspilled (X.TEMP temp))
                then raise ErrorMsg.InternalError "unspill not supported" (*[X.MOV ((X.REL (base, offs, 0w1), Tm.Quad), (X.REG xreg, Tm.Quad))]*)
                else nil
            end
        | spill (X.STACKARG _, _) = raise ErrorMsg.InternalError "Cannot spill to a stack arg"
        | spill _ = nil        (* Nothing else can be spilled. *)
      fun unspill (X.TEMP temp, xreg: Blarg.reg) =    (* Unspill a register if need be. *)
            let
              val base = X.REG X.SP
              val offs = Word.fromInt (stackpos (temptonum temp))
            in
              if (isspilled (X.TEMP temp))
                then raise ErrorMsg.InternalError "unspill not supported" (*[X.MOV ((X.REG xreg, Tm.Quad), (X.REL (base, offs, 0w1), Tm.Quad))]*)
                else nil
            end
        | unspill (X.STACKARG arg, xreg) =
            let
              val base = X.REG X.SP
              val offs = Word.fromInt (stacksz + 8 + (arg * 8))
            in
              (*[X.MOV ((X.REG xreg, s), (X.REL (base, offs, 0w1), s))]*)
              raise ErrorMsg.InternalError "unspill from stack not supported"
            end
        | unspill _ = nil

      fun unspill_ops (op1, op2) =
        case (isspilled op1, isspilled op2)
        of (false, false) => []
         | (true, false) => unspill (op1, spillreg1)
         | (false, true) => unspill (op2, spillreg2)
         | (true, true)  => unspill (op1, spillreg1) @ unspill (op2, spillreg2)
      
      fun respill_ops (op1, op2) =
        case (isspilled op1, isspilled op2) (* no instruction writes back to op2 *)
        of (false, _) => []
         | (true, _) => spill (op1, spillreg1)
      
      fun real_op1 op1 =
        case op1
        of (X.TEMP temp) => if isspilled op1
                            then (X.REG spillreg1)
                            else X.REG (temptoreg temp)
         | (X.STACKARG arg) => X.REG spillreg1
         | r => r
      
      fun real_ops (op1, op2) =
        (case op1
         of (X.TEMP temp) => if isspilled op1
                             then (X.REG spillreg1)
                             else X.REG (temptoreg temp)
          | (X.STACKARG arg) => X.REG spillreg1
          | r => r,
        case op2
         of (X.TEMP temp) => if isspilled op2
                             then (X.REG spillreg2)
                             else X.REG (temptoreg temp)
          | (X.STACKARG arg) => X.REG spillreg2
          | r => r)

      fun whack_insn (pred, insn, op1, op2) =
        (map (fn i => X.INSN (pred, i)) (unspill_ops (op1, op2))) @
        [ X.INSN (pred, insn (real_ops (op1, op2))) ] @
        (map (fn i => X.INSN (pred, i)) (respill_ops (op1, op2)))

      fun transform (X.DIRECTIVE s) = [X.DIRECTIVE s]
        | transform (X.COMMENT s) = [X.COMMENT s]
        | transform (X.LABEL l) = [X.LABEL l]
        | transform (X.LIVEIGN a) = transform a
        
        (* god the special cases are going to suck *)
        | transform (X.INSN (pred, X.MOVLIT (op1, w))) =
            [ X.INSN (pred, X.MOVLIT (real_op1 op1, w)) ] @
            (if isspilled op1
             then spill (op1, spillreg1)
             else [])
        | transform (X.INSN (pred, X.MOVSYM (op1, w))) =
            [ X.INSN (pred, X.MOVSYM (real_op1 op1, w)) ] @
            (if isspilled op1
             then spill (op1, spillreg1)
             else [])
        | transform (X.INSN (pred, X.MOVLBL (op1, w))) =
            [ X.INSN (pred, X.MOVLBL (real_op1 op1, w)) ] @
            (if isspilled op1
             then spill (op1, spillreg1)
             else [])
        
        (* and here comes the boilerplate *)
        | transform (X.INSN (pred, X.LDR (op1, op2))) =  whack_insn (pred, X.LDR, op1, op2)
        | transform (X.INSN (pred, X.STO (op1, op2))) =  whack_insn (pred, X.STO, op1, op2)
        | transform (X.INSN (pred, X.MOV (op1, op2))) =  whack_insn (pred, X.MOV, op1, op2)
        | transform (X.INSN (pred, X.MOVS (op1, op2))) = whack_insn (pred, X.MOVS, op1, op2)
        | transform (X.INSN (pred, X.ADD (op1, op2))) =  whack_insn (pred, X.ADD, op1, op2)
        | transform (X.INSN (pred, X.ADDS (op1, op2))) = whack_insn (pred, X.ADDS, op1, op2)
        | transform (X.INSN (pred, X.SUB (op1, op2))) =  whack_insn (pred, X.SUB, op1, op2)
        | transform (X.INSN (pred, X.SUBS (op1, op2))) = whack_insn (pred, X.SUBS, op1, op2)
        | transform (X.INSN (pred, X.AND (op1, op2))) =  whack_insn (pred, X.AND, op1, op2)
        | transform (X.INSN (pred, X.ANDS (op1, op2))) = whack_insn (pred, X.ANDS, op1, op2)
        | transform (X.INSN (pred, X.NOT (op1, op2))) =  whack_insn (pred, X.NOT, op1, op2)
        | transform (X.INSN (pred, X.NOTS (op1, op2))) = whack_insn (pred, X.NOTS, op1, op2)
        | transform (X.INSN (pred, X.PUSH (op1, op2))) = if isspilled op2
                                                         then raise ErrorMsg.InternalError "PUSH on spilled op2 is not possible"
                                                         else [ X.INSN (pred, X.PUSH (real_ops (op1, op2))) ]
        | transform (X.INSN (pred, X.POP (X.REG X.SP, X.REG X.PC))) = [ X.INSN (pred, X.MOVLBL (X.REG X.PC, endlbl)) ] (* optimize epilogue? *)
        | transform (X.INSN (pred, X.POP (op1, op2))) =  if isspilled op2
                                                         then raise ErrorMsg.InternalError "POP on spilled op2 is not possible"
                                                         else [ X.INSN (pred, X.POP (real_ops (op1, op2))) ]
        | transform (X.INSN (pred, X.CALL (op1, op2, i))) =  if isspilled op2
                                                             then raise ErrorMsg.InternalError "CALL on spilled op2 is not possible"
                                                             else [ X.INSN (pred, X.CALL ((fn (x, y) => (x, y, i)) (real_ops (op1, op2)))) ]
        | transform (X.INSN (pred, X.SHR (op1, op2))) =  whack_insn (pred, X.SHR, op1, op2)
        | transform (X.INSN (pred, X.SHL (op1, op2))) =  whack_insn (pred, X.SHL, op1, op2)
        (*| transform _ = raise ErrorMsg.InternalError "unimplemented"*)
    in
      (*if (nsave < 2) then
        List.concat (prologue :: (map transform instrs))
      else
      *)
      List.concat (prologue ::
                   ((map transform instrs) @
                    [[X.LABEL endlbl],
                     epilogue,
                     [X.INSN (X.AL, X.POP (X.REG X.SP, X.REG X.PC))]
                    ]
                   )
                  )
    end
end