Theory TranslComp

theory TranslComp
imports TranslCompTp
(*  Title:      HOL/MicroJava/Comp/TranslComp.thy
Author: Martin Strecker
*)


(* Compiling MicroJava into MicroJVM -- Translation functions *)

theory TranslComp imports TranslCompTp begin


(* parameter java_mb only serves to define function index later *)


(**********************************************************************)
(** code generation for expressions **)

primrec compExpr :: "java_mb => expr => instr list"
and compExprs :: "java_mb => expr list => instr list"
where

(*class instance creation*)
"compExpr jmb (NewC c) = [New c]" |

(*type cast*)
"compExpr jmb (Cast c e) = compExpr jmb e @ [Checkcast c]" |


(*literals*)
"compExpr jmb (Lit val) = [LitPush val]" |


(* binary operation *)
"compExpr jmb (BinOp bo e1 e2) = compExpr jmb e1 @ compExpr jmb e2 @
(case bo of Eq => [Ifcmpeq 3,LitPush(Bool False),Goto 2,LitPush(Bool True)]
| Add => [IAdd])"
|

(*local variable*)
"compExpr jmb (LAcc vn) = [Load (index jmb vn)]" |


(*assignement*)
"compExpr jmb (vn::=e) = compExpr jmb e @ [Dup , Store (index jmb vn)]" |


(*field access*)
"compExpr jmb ( {cn}e..fn ) = compExpr jmb e @ [Getfield fn cn]" |


(*field assignement - expected syntax: {_}_.._:=_ *)
"compExpr jmb (FAss cn e1 fn e2 ) =
compExpr jmb e1 @ compExpr jmb e2 @ [Dup_x1 , Putfield fn cn]"
|


(*method call*)
"compExpr jmb (Call cn e1 mn X ps) =
compExpr jmb e1 @ compExprs jmb ps @ [Invoke cn mn X]"
|


(** code generation expression lists **)

"compExprs jmb [] = []" |

"compExprs jmb (e#es) = compExpr jmb e @ compExprs jmb es"


primrec compStmt :: "java_mb => stmt => instr list" where

(** code generation for statements **)

"compStmt jmb Skip = []" |

"compStmt jmb (Expr e) = ((compExpr jmb e) @ [Pop])" |

"compStmt jmb (c1;; c2) = ((compStmt jmb c1) @ (compStmt jmb c2))" |

"compStmt jmb (If(e) c1 Else c2) =
(let cnstf = LitPush (Bool False);
cnd = compExpr jmb e;
thn = compStmt jmb c1;
els = compStmt jmb c2;
test = Ifcmpeq (int(length thn +2));
thnex = Goto (int(length els +1))
in
[cnstf] @ cnd @ [test] @ thn @ [thnex] @ els)"
|

"compStmt jmb (While(e) c) =
(let cnstf = LitPush (Bool False);
cnd = compExpr jmb e;
bdy = compStmt jmb c;
test = Ifcmpeq (int(length bdy +2));
loop = Goto (-(int((length bdy) + (length cnd) +2)))
in
[cnstf] @ cnd @ [test] @ bdy @ [loop])"


(**********************************************************************)

(*compiling methods, classes and programs*)

(*initialising a single variable*)
definition load_default_val :: "ty => instr" where
"load_default_val ty == LitPush (default_val ty)"

definition compInit :: "java_mb => (vname * ty) => instr list" where
"compInit jmb == λ (vn,ty). [load_default_val ty, Store (index jmb vn)]"

definition compInitLvars :: "[java_mb, (vname × ty) list] => bytecode" where
"compInitLvars jmb lvars == concat (map (compInit jmb) lvars)"

definition compMethod :: "java_mb prog => cname => java_mb mdecl => jvm_method mdecl" where
"compMethod G C jmdl == let (sig, rT, jmb) = jmdl;
(pns,lvars,blk,res) = jmb;
mt = (compTpMethod G C jmdl);
bc = compInitLvars jmb lvars @
compStmt jmb blk @ compExpr jmb res @
[Return]
in (sig, rT, max_ssize mt, length lvars, bc, [])"


definition compClass :: "java_mb prog => java_mb cdecl=> jvm_method cdecl" where
"compClass G == λ (C,cno,fdls,jmdls). (C,cno,fdls, map (compMethod G C) jmdls)"

definition comp :: "java_mb prog => jvm_prog" where
"comp G == map (compClass G) G"

end