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-rw-r--r--src/codegen.ml706
1 files changed, 704 insertions, 2 deletions
diff --git a/src/codegen.ml b/src/codegen.ml
index 2709526..3849bfa 100644
--- a/src/codegen.ml
+++ b/src/codegen.ml
@@ -1,6 +1,708 @@
open Mips
+open Typing
+
+exception Very_bad_error of string
+
+exception Reference_register of register
+
+(* Convention pour les registres :
+ - a0, a1, a2, a3 : contiennent les (éventuels) 4 premiers arguments de la fonction
+ - v0 : contient la valeur de retour des fonctions (rien de particulier pour un constructeur)
+ - v0-v1, t0-t9, s0-s1 : utilisés pour les calculs
+ - fp contient un pointeur de frame mis à jour pour chaque appel
+ de fonction
+ - sp n'est pas tenu à jour en fonction de l'état de la pile, par contre il est
+ utilisé lors d'un appel de fonction pour pouvoir définir le nouvea fp,
+ il est donc mis à jour avant chaque appel de fonction pour effectivement refléter
+ l'état d'utilisation de la pile (pile sur laquelle il peut d'ailleurs y avoir
+ des arguments excedentaires)
+ Tous les registres doivent être sauvés par l'appellant sauf fp
+ Les registres a0, a1, a2, a3 sont susceptibles d'être modifiés par la fonction appellée.
+ **sauf dans le cas où a0 représente this** !!
+*)
+
+(* Environnement pour accéder aux variables *)
+type whereis_var =
+ | VGlobal
+ | VStack of int (* position relative à $fp *)
+ | VStackByRef of int
+ | VRegister of register
+ | VRegisterByRef of register
+
+type cg_env = {
+ c_penv : env;
+ c_names : whereis_var Smap.t;
+ c_ret_ref : bool;
+ c_ret_lbl : string;
+ c_fp_used : int;
+ c_need_fp : bool ref;
+ c_save_regs : register list;
+ c_free_regs : register list;
+}
+
+let env_push n e =
+ if n <> 0 then e.c_need_fp := true;
+ let kk = e.c_fp_used + n in
+ { e with c_fp_used = kk }, -kk
+
+let env_add_var vid vv e =
+ { e with c_names = Smap.add vid vv e.c_names }
+
+let env_get_free_reg e =
+ let r, more = List.hd e.c_free_regs, List.tl e.c_free_regs in
+ { e with
+ c_free_regs = more;
+ c_save_regs = r::e.c_save_regs }, r
+
+let globals_env = ref Smap.empty
+
+(* Chaînes de caractères utilisées dans le programme *)
+let strings = Hashtbl.create 12 (* string -> label *)
+
+(* Identifiants uniques pour divers objets - essentiellement labels *)
+let id =
+ let last = ref 0 in
+ fun prefix -> (last := !last + 1; prefix ^ (string_of_int !last))
+
+(* Doit-on se préparer à faire des appels de fonction ? Ie sauvegarder $ra *)
+let rec expr_does_call e = match e.te_desc with
+ | TEInt _ | TENull | TEThis | TEIdent _ -> false
+ | TEAssign(a, b) -> expr_does_call a || expr_does_call b
+ | TECallFun (_, _, _) -> true
+ | TECallVirtual (_, _, _, _) -> true
+ | TEUnary (_, e) -> expr_does_call e
+ | TEBinary (a, _, b) -> expr_does_call a || expr_does_call b
+ | TEMember (e, _) -> expr_does_call e
+ | TEPointerCast(e, _) -> expr_does_call e
+ | TENew(_, _, _) -> true
+let rec stmt_does_call = function
+ | TSEmpty | TSReturn(None) -> false
+ | TSExpr(e) -> expr_does_call e
+ | TSIf (e, sa, sb) -> expr_does_call e || stmt_does_call sa || stmt_does_call sb
+ | TSWhile(e, s) -> expr_does_call e || stmt_does_call s
+ | TSFor(e, f, g, s) -> (List.exists expr_does_call e) || (match f with | None -> false | Some k -> expr_does_call k)
+ || (List.exists expr_does_call g) || stmt_does_call s
+ | TSBlock(k) -> List.exists stmt_does_call k
+ | TSReturn(Some k) -> expr_does_call k
+ | TSDeclare(TClass _, _) -> true
+ | TSDeclare (_, _) -> false
+ | TSDeclareAssignExpr(_, _, e) -> expr_does_call e
+ | TSDeclareAssignConstructor(_, _, _, _) -> true
+ | TSWriteCout(l) -> List.exists (function | TSEExpr e -> expr_does_call e | TSEStr _ -> false) l
+
+
+(* La génération de code, enfin ! *)
+
+(* Arguments de la fonction gen_expr :
+ - un environnement : permet de savoir plein de choses, par exemple combien de place est
+ utilisée sur la pile en-dessous de $fp
+ - une liste de registres disponnibles pour faire le calcul
+ *qui doit toujours contenir au moins un registre*
+ - une liste de registres à sauvegarder dans tous les cas
+ - l'expression pour laquelle on veut générer du code
+
+ À l'issue d'un appel à gen_expr, il y a plusieurs possibilités, exprimées
+ par le type union expr_type décrit ci-dessus :
+ - le premier registre de la liste des registres disponnibles (noté r) contient
+ une adresse qui est l'adresse de la valeur dénotée par l'expression
+ - la valeur dénotée est stockée dans x(reg) pour un certain reg et un certain x
+ - la valeur est stockée dans un certain registre a, qui est son
+ "registre de référence", ie si on doit affecter à cette valeur on peut
+ modifier ce registre
+ - la valeur est stockée dans le registre r
+ Dans tous les cas sauf le dernier, on peut modifier la valeur dénotée par
+ l'expression (par exemple lors d'une affectation).
+ Si le typage nous garantit que l'expression ne peut pas être affectée, on peut
+ utiliser l'artifice de dire qu'une valeur est placée dans un registre comme
+ "registre de référence" même lorsque ce n'est pas le cas (= jouer avec le feu).
+*)
+
+(* possibilités pour ce qui est généré par gen_expr *)
+type expr_type =
+ | Addr (* top register contains address of value *)
+ | AddrByReg of int * register (* value at int(register) *)
+ | Value of register (* other register is home to the value *)
+ | Copy (* top register contains copy of value *)
+
+(* on a fait un appel à gen_expr, maintenant on veut être sûr d'avoir
+ soit l'adresse soit la valeur dans tel ou tel registre *)
+let cla r a = match a with
+ | Addr -> nop
+ | AddrByReg(x, rg) -> la r areg (x, rg)
+ | Value r -> raise (Reference_register r)
+ | _ -> assert false
+let cr r a = match a with (* conditionnally read *)
+ | Addr -> lw r areg (0, r)
+ | AddrByReg(x, rg) -> lw r areg (x, rg)
+ | Copy -> nop
+ | Value k -> if r <> k then move r k else nop
+let crb r q a = match a with
+ | Value k -> q, k
+ | _ -> q ++ cr r a, r
+
+let spare_reg = s0
+let spare_reg2 = s1
+
+(* Cette fonction prévoit de l'espace sur la pile pour enregistrer les
+ valeurs de tous les registres save_regs à sauvegarder (elle donne un nouvel
+ environnement où la place nécessaire est réservée) et génère le code
+ nécessaire à la sauvegarde et à la restauration.
+ Le nouvel environnement est également modifié de manière à ce que de futurs
+ appels à des valeurs qui devaient être enregistrées dans des registres sauvegardés
+ soient maintenant fait en prenant en compte la relocalisation de ces valeurs
+ sur la pile. *)
+let saver env save_regs =
+ List.fold_left
+ (fun (code, more_code, env) r ->
+ let new_fp_used = env.c_fp_used + 4 in
+ let pos = - new_fp_used in
+ env.c_need_fp := true;
+ code ++ sw r areg (pos, fp), lw r areg (pos, fp) ++ more_code,
+ { env with
+ c_names = Smap.map
+ (function
+ | VRegister k when k = r -> VStack (pos)
+ | VRegisterByRef k when k = r -> VStackByRef(pos)
+ | a -> a) env.c_names;
+ c_fp_used = new_fp_used;
+ c_save_regs = (List.filter ((<>) r) env.c_save_regs) }
+ )
+ (nop, nop, env) save_regs
+
+(*
+ renvoie le résultat dans le premier registre de free_regs
+ ou autre (cf ci-dessus)
+*)
+let rec gen_expr env free_regs save_regs e =
+ (* register management *)
+ let r = List.hd free_regs in (* register where to put result *)
+ let more = List.tl free_regs in
+ (* generate the code... *)
+ match e.te_desc with
+ | TEInt(k) -> li r k, Copy
+ | TENull -> nop, Value zero
+ | TEThis -> (* convention : this is always the first argument, so in a0 *)
+ begin match Smap.find "this" env.c_names with
+ | VRegister(k) when k <> r -> nop, Value k
+ | VStack(i) -> nop, AddrByReg(i, fp)
+ | _ -> assert false
+ end
+ | TEIdent(i) ->
+ begin match Smap.find i env.c_names with
+ | VGlobal -> la r alab i, Addr
+ | VStack(i) -> nop, AddrByReg(i, fp)
+ | VStackByRef(i) -> lw r areg (i, fp), Addr
+ | VRegister(k) -> nop, Value k
+ | VRegisterByRef(k) -> nop, AddrByReg(0, k)
+ end
+ | TEAssign(e1, e2) ->
+ begin match more with
+ | [] ->
+ let t1, ae1 = gen_expr env free_regs save_regs e1 in
+ let env2, tspot = env_push 4 env in
+ let t2, ae2 = gen_expr env2 free_regs save_regs e2 in
+ let t2 = t2 ++ cr r ae2 in
+ begin match ae1 with
+ | Addr -> t1 ++ sw r areg (tspot, fp) ++ t2 ++ lw spare_reg areg (tspot, fp) ++ sw r areg (0, spare_reg), Copy
+ | AddrByReg (x, rg) when t1 = nop -> t2 ++ sw r areg (x, rg), Copy
+ | Value k when t1 = nop && k <> r -> t2 ++ move k r, Copy
+ | _ -> assert false
+ end
+ | b::_ ->
+ let t1, ae1 = gen_expr env more (r::save_regs) e1 in
+ let t2, ae2 = gen_expr env free_regs save_regs e2 in
+ let t2, r2 = crb r t2 ae2 in
+ let tr = if r2 = r then Copy else Value r2 in
+ begin match ae1 with
+ | Addr -> t2 ++ t1 ++ sw r2 areg (0, b), tr
+ | AddrByReg (x, rg) when t1 = nop -> t2 ++ sw r2 areg (x, rg), tr
+ | Value k when t1 = nop && k <> r2 -> t2 ++ move k r2, tr
+ | _ -> assert false
+ end
+ end
+ | TECallFun(id, args, b) ->
+ let keep_result_in_v0 = (not (List.mem v0 save_regs)) || r = v0 in
+ let code_save_regs, code_restore_regs, env_regs_saved = saver env save_regs in
+ let args_code, _, env_args = code_for_args env_regs_saved args [ a0; a1; a2; a3 ] in
+ code_save_regs
+ ++ args_code
+ ++ la sp areg (-env_args.c_fp_used, fp) ++ jal id
+ ++ (if keep_result_in_v0 then nop else move r v0)
+ ++ code_restore_regs,
+ if b
+ then (if keep_result_in_v0 then AddrByReg (0, v0) else Addr)
+ else (if keep_result_in_v0 then Value(v0) else Copy)
+ | TECallVirtual(obj, fi, args, b) ->
+ let keep_result_in_v0 = (not (List.mem v0 save_regs)) || r = v0 in
+ let code_save_regs, code_restore_regs, env_regs_saved = saver env save_regs in
+ let args_code, sr, env_args = code_for_args env_regs_saved ((obj, true)::args) [ a0; a1; a2; a3 ] in
+ code_save_regs
+ ++ args_code
+ ++ lw v0 areg (0, a0) ++ lw v0 areg (fi, v0)
+ ++ la sp areg (-env_args.c_fp_used, fp) ++ jalr v0
+ ++ (if keep_result_in_v0 then nop else move r v0)
+ ++ code_restore_regs,
+ if b
+ then (if keep_result_in_v0 then AddrByReg (0, v0) else Addr)
+ else (if keep_result_in_v0 then Value(v0) else Copy)
+ | TEUnary (x, e) ->
+ let t, a = gen_expr env free_regs save_regs e in
+ begin match x with
+ | Ast.Deref ->
+ begin match a with
+ | Value r -> t, AddrByReg (0, r)
+ | _ -> t ++ cr r a, Addr
+ end
+ | Ast.Ref ->
+ t ++ cla r a, Copy
+ | Ast.Plus -> t ++ cr r a, Copy
+ | Ast.Minus -> t ++ cr r a ++ neg r r, Copy
+ | Ast.Not -> t ++ cr r a ++ not_ r r, Copy
+ | Ast.PreIncr | Ast.PreDecr ->
+ let delta = if x = Ast.PreIncr then 1 else -1 in
+ begin match a with
+ | Addr ->
+ t ++ move spare_reg r ++ lw r areg (0, spare_reg)
+ ++ add r r oi delta ++ sw r areg (0, spare_reg), Copy
+ | AddrByReg (k, rg) when t = nop && r <> rg ->
+ lw r areg (k, rg)
+ ++ add r r oi delta ++ sw r areg (k, rg), Copy
+ | Value v when t = nop && v <> r ->
+ add v v oi delta ++ move r v, Copy
+ | _ -> assert false
+ end
+ | Ast.PostIncr | Ast.PostDecr ->
+ let delta = if x = Ast.PostIncr then 1 else -1 in
+ begin match a with
+ | Addr ->
+ t ++ move spare_reg r
+ ++ lw r areg(0, spare_reg)
+ ++ add spare_reg2 r oi delta
+ ++ sw spare_reg2 areg(0, spare_reg), Copy
+ | AddrByReg (k, rg) when t = nop && r <> rg ->
+ lw r areg (k, rg)
+ ++ add spare_reg r oi delta
+ ++ sw spare_reg areg (k, rg), Copy
+ | Value v when t = nop && v <> r ->
+ move r v ++ add v v oi delta, Copy
+ | _ -> assert false
+ end
+ end
+ | TEBinary(e1, op, e2) when op <> Ast.Lor && op <> Ast.Land ->
+ let rs, rb, precode = match more with
+ | [] ->
+ let env2, tspot = env_push 4 env in
+ let t1, ae1 = gen_expr env2 free_regs save_regs e1 in
+ let t2, ae2 = gen_expr env free_regs save_regs e2 in
+ let t1, r1 = crb r t1 ae1 in
+ let t2, r2 = crb r t2 ae2 in
+ r1, spare_reg, t2 ++ sw r2 areg (tspot, fp) ++ t1 ++ lw spare_reg areg (tspot, fp)
+ | b::_ ->
+ let t1, ae1 = gen_expr env free_regs save_regs e1 in
+ let t2, ae2 = gen_expr env more (r::save_regs) e2 in
+ let t1, rs = crb r t1 ae1 in
+ let t2, rb = crb b t2 ae2 in
+ rs, rb, t1 ++ t2
+ in
+ precode ++ (match op with
+ | Ast.Add -> add r rs oreg rb
+ | Ast.Sub -> sub r rs oreg rb
+ | Ast.Mul -> mul r rs oreg rb
+ | Ast.Div -> div r rs oreg rb
+ | Ast.Modulo -> rem r rs oreg rb
+ | Ast.Equal -> seq r rs rb
+ | Ast.NotEqual -> sne r rs rb
+ | Ast.Lt -> slt r rs rb
+ | Ast.Le -> sle r rs rb
+ | Ast.Gt -> sgt r rs rb
+ | Ast.Ge -> sge r rs rb
+ | _ -> assert false
+ ), Copy
+ | TEBinary(e1, op, e2) (* when op = Ast.Lor || op = Ast.Land *) ->
+ let t1, ae1 = gen_expr env free_regs save_regs e1 in
+ let t2, ae2 = gen_expr env free_regs save_regs e2 in
+ let t1 = t1 ++ cr r ae1 in
+ let t2 = t2 ++ cr r ae2 in
+ let lazy_lbl = id "_lazy" in
+ t1 ++ (if op = Ast.Lor then bnez r lazy_lbl else beqz r lazy_lbl)
+ ++ t2 ++ label lazy_lbl ++ sne r r zero, Copy
+ | TEMember(e, i) ->
+ let c, a = gen_expr env free_regs save_regs e in
+ if i <> 0 then begin
+ match a with
+ | Addr -> c ++ la r areg (i, r), Addr
+ | AddrByReg (k, rg) when c = nop -> nop, AddrByReg (k + i, rg)
+ | _ -> assert false
+ end else
+ c, a
+ | TEPointerCast(e, i) ->
+ let c, a = gen_expr env free_regs save_regs e in
+ c ++ cr r a ++ (if i = 0 then nop else la r areg (i, r)), Copy
+ | TENew(cls, constr, args) ->
+ let code_save_regs, code_restore_regs, env_regs_saved = saver env save_regs in
+ let args_code, _, env_args = code_for_args env_regs_saved args [ a1; a2; a3 ] in
+ code_save_regs ++ args_code
+ ++ li v0 9 ++ li a0 cls.tc_size ++ syscall ++ move a0 v0
+ ++ la sp areg (-env_args.c_fp_used, fp) ++ jal constr
+ ++ (if r <> a0 then move r a0 else nop) ++ code_restore_regs, Copy
+and code_for_args env arg_list regs =
+ (* assigne registers to possibly in-register arguments *)
+ let args_in_regs, args_in_stack, _ = List.fold_left
+ (fun (ir, is, fr) (arg, byref) ->
+ match fr with
+ | [] -> ir, (arg, byref)::is, []
+ | r::nfr -> (r, (arg, byref))::ir, is, nfr)
+ ([], [], regs) arg_list in
+ (* allocate stack for remaining args *)
+ let stack_use = 4 * List.length args_in_stack in
+ let kenv, _ = env_push stack_use env in
+ (* make code for in-stack arguments *)
+ let args_in_stack = List.rev args_in_stack in
+ let code_for_stack, _ = List.fold_left
+ (fun (code, u) (arg, byref) ->
+ let c, addr = gen_expr kenv (v0::kenv.c_free_regs) [] arg in
+ (if byref then
+ c ++ cla v0 addr ++ sw v0 areg (-kenv.c_fp_used + u, fp) ++ code, u+4
+ else
+ let c, freg = crb v0 c addr in
+ c ++ sw freg areg (-kenv.c_fp_used + u, fp) ++ code, u+4
+ )
+ ) (nop, 0) args_in_stack in
+ (* make code for in-register arguments *)
+ let arg_reg_do_call, arg_reg_dont_call =
+ List.partition (fun (_, (e, _)) -> expr_does_call e) args_in_regs in
+ let rec mk_code_callz e = function
+ | [] -> nop
+ | (reg, (expr, byref))::more_args ->
+ let c, addr = gen_expr e (reg::kenv.c_free_regs) [] expr in
+ if more_args = [] then
+ c ++ (if byref then cla reg addr else cr reg addr)
+ else
+ let e2, pos = env_push 4 e in
+ (if byref then
+ c ++ cla reg addr ++ sw reg areg (pos, fp)
+ else
+ let tt, r2 = crb reg c addr in
+ tt ++ sw r2 areg (pos, fp))
+ ++ (mk_code_callz e2 more_args) ++ lw reg areg (pos, fp)
+ in
+ let code_reg_do_call = mk_code_callz kenv arg_reg_do_call in
+ let code_reg_dont_call, _ =
+ List.fold_left
+ (fun (code, ur) (reg, (expr, byref)) ->
+ let c, addr = gen_expr kenv (reg::kenv.c_free_regs) ur expr in
+ code ++ c ++ (if byref then cla reg addr else cr reg addr), reg::ur)
+ (nop, []) arg_reg_dont_call
+ in
+ let code = code_for_stack ++ code_reg_do_call ++ code_reg_dont_call
+ in code, (List.map fst args_in_regs), kenv
+
+
+let gen_expr_dr dr env = gen_expr env (dr::env.c_free_regs) env.c_save_regs
+let gen_expr_v0 = gen_expr_dr v0
+
+let rec gen_stmt alloc_vars_in_regs env = function
+ | TSEmpty -> nop, env
+ | TSExpr(e) ->
+ comment "expr" ++ (fst (gen_expr_v0 env e)), env
+ | TSIf(cond, s1, s2) ->
+ let c, a = gen_expr_v0 env cond in
+ let c, reg = crb v0 c a in
+ let l_else = id "_cond_else" in
+ let l_end = id "_cond_end" in
+ let c_then = gen_block env [s1] in
+ let c_else = gen_block env [s2] in
+ comment "if"
+ ++ c ++ beqz reg l_else
+ ++ c_then ++ b l_end
+ ++ label l_else ++ c_else
+ ++ label l_end, env
+ | TSWhile(cond, body) ->
+ let c, a = gen_expr_v0 env cond in
+ let c, reg = crb v0 c a in
+ let l_begin = id "_while_begin" in
+ let l_cond = id "_while_cond" in
+ let c_body = gen_block env [body] in
+ comment "while" ++ b l_cond
+ ++ label l_begin ++ c_body
+ ++ label l_cond ++ c ++ bnez reg l_begin, env
+ | TSFor(before, cond, after, body) ->
+ let l_begin = id "_for_begin" in
+ let l_cond = id "_for_cond" in
+ let c_before = List.fold_left
+ (fun code expr -> let c, _ = gen_expr_v0 env expr in code ++ c) nop before in
+ let c_after = List.fold_left
+ (fun code expr -> let c, _ = gen_expr_v0 env expr in code ++ c) nop after in
+ let c_cond = match cond with
+ | None -> b l_begin
+ | Some x ->
+ let c, a = gen_expr_v0 env x in
+ let c, reg = crb v0 c a in
+ c ++ bnez reg l_begin in
+ let c_body = gen_block env [body] in
+ comment "for"
+ ++ c_before ++ b l_cond
+ ++ label l_begin ++ c_body ++ c_after
+ ++ label l_cond ++ c_cond, env
+ | TSBlock(b) ->
+ let c = gen_block env b in
+ comment "block" ++ c, env
+ | TSReturn (None) ->
+ comment "return" ++ b env.c_ret_lbl, env
+ | TSReturn (Some e) ->
+ let c, a = gen_expr_v0 env e in
+ comment "return"
+ ++ c ++ (if env.c_ret_ref then cla v0 a else cr v0 a)
+ ++ b env.c_ret_lbl, env
+ | TSDeclare (ty, id) ->
+ if num ty && alloc_vars_in_regs && List.length env.c_free_regs > 5 then
+ (* allocate variable in register *)
+ let env2, reg = env_get_free_reg env in
+ comment ("declare " ^ id) ++ move reg zero,
+ env_add_var id (VRegister reg) env2
+ else
+ let s = type_size env.c_penv ty in
+ let env2, pos = env_push s env in
+ let code = match ty with
+ | TClass(i) ->
+ let c = get_c env.c_penv i in
+ let cproto = List.find
+ (fun p -> p.tp_ret_type = None && p.tp_name = i && p.tp_args = []) c.tc_methods in
+ let code_save_regs, code_restore_regs, env_regs_saved = saver env2 env.c_save_regs in
+ code_save_regs
+ ++ la a0 areg (pos, fp)
+ ++ la sp areg (-env_regs_saved.c_fp_used, fp) ++ jal cproto.tp_unique_ident
+ ++ code_restore_regs
+ | _ -> sw zero areg (pos, fp)
+ in
+ comment ("declare " ^ id) ++ code,
+ env_add_var id (VStack pos) env2
+ | TSDeclareAssignConstructor(cls, id, constr, args) ->
+ let env2, pos = env_push cls.tc_size env in
+ let code =
+ let code_save_regs, code_restore_regs, env_regs_saved = saver env2 env.c_save_regs in
+ let args_code, _, env_args = code_for_args env_regs_saved args [ a1; a2; a3 ] in
+ code_save_regs
+ ++ args_code ++ la a0 areg(pos, fp)
+ ++ la sp areg (-env_args.c_fp_used, fp) ++ jal constr
+ ++ code_restore_regs
+ in
+ comment ("declare " ^ id) ++ code,
+ env_add_var id (VStack pos) env2
+ | TSDeclareAssignExpr ((ty, ref), id, e) ->
+ assert (ref || num ty);
+ if alloc_vars_in_regs && List.length env.c_free_regs > 5 then
+ (* allocate variable in register *)
+ let env2, reg = env_get_free_reg env in
+ let code, a = gen_expr env (reg::env2.c_free_regs) env.c_save_regs e in
+ comment ("declare " ^ id)
+ ++ code ++ (if ref then cla reg a else cr reg a),
+ env_add_var id (if ref then VRegisterByRef reg else VRegister reg) env2
+ else
+ let code, a = gen_expr_v0 env e in
+ let env2, pos = env_push 4 env in
+ comment ("declare " ^ id)
+ ++ (if ref then
+ code ++ cla v0 a ++ sw v0 areg (pos, fp)
+ else
+ let k, b = crb v0 code a in
+ k ++ sw b areg (pos, fp)
+ ),
+ env_add_var id (if ref then VStackByRef pos else VStack pos) env2
+ | TSWriteCout(sl) ->
+ let save_code, restore_code, env2 = saver env
+ (if List.mem a0 env.c_save_regs then [a0] else []) in
+ let text1 = List.fold_left
+ (fun text -> function
+ | TSEExpr(e) ->
+ let t, a = gen_expr_dr a0 env2 e in
+ text ++ t ++ cr a0 a ++ li v0 1 ++ syscall
+ | TSEStr(s) ->
+ let l =
+ if Hashtbl.mem strings s then
+ Hashtbl.find strings s
+ else
+ let l = id "_s" in Hashtbl.add strings s l;
+ l
+ in
+ text ++ la a0 alab l ++ li v0 4 ++ syscall)
+ nop sl in
+ comment "cout<<..."
+ ++ save_code ++ text1 ++ restore_code, env
+and gen_block env b =
+ let rec fold env = function
+ | [] -> nop
+ | stmt::next ->
+ let does_call_after = List.exists stmt_does_call next in
+ try
+ let tt, ee = gen_stmt (not does_call_after) env stmt in
+ let more_code = fold ee next in
+ tt ++ more_code
+ with Reference_register _ ->
+ let tt, ee = gen_stmt false env stmt in
+ let more_code = fold ee next in
+ tt ++ more_code
+ in
+ fold env b
+
+let gen_decl tenv decl = match decl with
+ | TDGlobal(ty, id) ->
+ globals_env := Smap.add id VGlobal !globals_env;
+ let bytes = type_size tenv ty in
+ nop, (label id) ++ (dword (let rec a n = if n > 0 then 0::(a (n-4)) else [] in a bytes))
+ | TDFunction(proto, block) ->
+ let regs_for_args, env0 = match proto.tp_class with
+ | None -> [ a0; a1; a2; a3 ], !globals_env
+ | Some k -> [ a1; a2; a3 ], Smap.add "this" (VRegister a0) !globals_env
+ in
+ let need_fp = ref false in
+ let names, _, free_regs = List.fold_left
+ (fun (env, p, regs) ((ty, r), id) ->
+ assert (r || type_size tenv ty = 4);
+ match regs with
+ | reg::more_regs ->
+ Smap.add id (if r then VRegisterByRef reg else VRegister reg) env, p, more_regs
+ | [] -> need_fp := true;
+ Smap.add id (if r then VStackByRef p else VStack p) env, p + 4, regs
+ )
+ (env0, 0, regs_for_args) proto.tp_args in
+ let env = {
+ c_penv = tenv;
+ c_names = names;
+ c_ret_ref = (match proto.tp_ret_type with | None -> false | Some(_, r) -> r);
+ c_ret_lbl = "_return_" ^ proto.tp_unique_ident;
+ c_fp_used = 8;
+ c_need_fp = need_fp;
+ c_free_regs = [ t0; t1; t2; t3; t4; t5; t6; t7; t8; t9; v1 ];
+ c_save_regs = List.filter (fun r -> not (List.mem r free_regs)) [a0; a1; a2; a3];
+ } in
+ let code_for_constructor, does_calls = match proto.tp_ret_type with
+ | Some _ -> nop, (List.exists stmt_does_call block)
+ | None -> let cls_name = (match proto.tp_class with | Some k -> k | None -> assert false) in
+ la sp areg (-8, fp) ++ jal (cls_name ^ "0"), true
+ in
+ let code_for_virtual = match proto.tp_virtual with
+ | Some (c, _) when c.h_pos <> 0 ->
+ la a0 areg (-c.h_pos, a0)
+ | _ -> nop
+ in
+ if does_calls
+ then
+ let save_code, unsave_code, env2 =
+ saver env (List.filter (fun x -> x <> a0 || proto.tp_class = None) env.c_save_regs)
+ in
+ let text = gen_block env2 block in
+ label proto.tp_unique_ident
+ ++ sw fp areg (-4, sp) ++ sw ra areg (-8, sp) ++ move fp sp
+ ++ code_for_virtual ++ save_code ++ code_for_constructor ++ text
+ ++ label env.c_ret_lbl ++ move sp fp ++ lw fp areg (-4, sp) ++ lw ra areg (-8, sp)
+ ++ jr ra, nop
+ else
+ let rec bb_fp e =
+ try
+ gen_block e block
+ with Reference_register r ->
+ let save_code, _, env2 = saver env [r] in
+ save_code ++ bb_fp env2
+ in
+ let text = bb_fp env in
+ label proto.tp_unique_ident
+ ++ (if !need_fp then sw fp areg (-4, sp) ++ move fp sp else nop)
+ ++ code_for_virtual ++ text
+ ++ label env.c_ret_lbl ++ (if !need_fp then move sp fp ++ lw fp areg (-4, sp) else nop)
+ ++ jr ra, nop
+ | TDClass(c) ->
+ let constructor_calls_something = ref false in
+ (* Call default constructor of parent classes *)
+ let code_parents = List.fold_left
+ (fun code parent ->
+ let cn = parent.h_class in
+ let c = get_c tenv cn in
+ let proto = List.find
+ (fun p -> p.tp_ret_type = None && p.tp_args = [] && p.tp_name = cn)
+ c.tc_methods in
+ constructor_calls_something := true;
+ code ++ (if parent.h_pos <> 0 then la a0 areg(parent.h_pos, a0) else nop)
+ ++ jal proto.tp_unique_ident ++ (if parent.h_pos <> 0 then lw a0 areg (-12, fp) else nop))
+ nop c.tc_hier.h_supers in
+ (* Build vtables and build constructor *)
+ let rec make_vtables hh =
+ (* calculate vtable contents *)
+ let vtable_size = List.fold_left (fun k (p, _) -> max k (p+4)) 0 hh.h_vtable in
+ let vtable_as_array = Array.make (vtable_size / 4) "_nothing" in
+ List.iter (fun (p, s) -> vtable_as_array.(p/4) <- s.tp_unique_ident) hh.h_vtable;
+ let vt_l = Array.to_list vtable_as_array in
+ (* code for vtable initialization *)
+ let vtable =
+ if vt_l = []
+ then nop
+ else label ("_vt_" ^ c.tc_name ^ "_as_" ^ hh.h_class) ++ address vt_l in
+ let constructor_code =
+ if vt_l = []
+ then nop
+ else la a1 alab ("_vt_" ^ c.tc_name ^ "_as_" ^ hh.h_class)
+ ++ sw a1 areg (hh.h_pos, a0) in
+ (* code for subclasses vtable initialization *)
+ List.fold_left
+ (fun (vt, cc) sup ->
+ let mvt, mcc = make_vtables sup in
+ vt ++ mvt, cc ++ mcc)
+ (vtable, constructor_code) hh.h_supers
+ in
+ let vtables, vtable_init_code = make_vtables c.tc_hier in
+ (* Initialize members *)
+ let init_code_proper = Smap.fold
+ (fun _ (ty, pos) code ->
+ code ++ (match ty with
+ | TClass(s) ->
+ let cs = get_c tenv s in
+ let proto = List.find
+ (fun p -> p.tp_ret_type = None && p.tp_args = [] && p.tp_name = s)
+ cs.tc_methods in
+ constructor_calls_something := true;
+ (if pos <> 0 then la a0 areg (pos, a0) else nop)
+ ++ la sp areg (-12, fp)
+ ++ jal proto.tp_unique_ident
+ ++ (if pos <> 0 then lw a0 areg (-12, fp) else nop)
+ | _ -> sw zero areg (pos, a0)))
+ c.tc_members nop
+ in (* Put it all together *)
+ label (c.tc_name ^ "0")
+ ++ (if !constructor_calls_something then
+ sw fp areg (-4, sp) ++ move fp sp ++ sw ra areg (-8, fp)
+ ++ sw a0 areg (-12, fp) ++ la sp areg (-12, fp)
+ else nop)
+ ++ code_parents ++ vtable_init_code ++ init_code_proper
+ ++ (if !constructor_calls_something then
+ lw ra areg (-8, fp) ++ move sp fp ++ lw fp areg (-4, sp)
+ else nop)
+ ++ jr ra, vtables
let generate p =
- { text = nop;
- data = nop }
+ try
+ let text, data = List.fold_left (fun (text, data) decl ->
+ let more_text, more_data = gen_decl p.prog_env decl in
+ text ++ more_text, data ++ more_data) (nop, nop) p.prog_decls in
+ let text =
+ label "main"
+ ++ jal p.prog_main
+ ++ li v0 10 ++ syscall
+ ++ label "_nothing" ++ jr ra
+ ++ text in
+ let str = Hashtbl.fold
+ (fun str lbl data -> data ++ label lbl ++ asciiz str)
+ strings nop in
+ { text = text;
+ data = data ++ str }
+ with
+ | Assert_failure (k, a, b) -> raise (Very_bad_error (
+ "(unexpected) Assertion failure: "^k^" at "^(string_of_int a)^":"^(string_of_int b)))
+ | Not_found -> raise (Very_bad_error ("(unexpected) Not found"))
+ | Invalid_argument(k) -> raise (Very_bad_error ("(unexpected) Invalid argument: "^k))
+ | Match_failure(k, a, b) -> raise (Very_bad_error (
+ "(unexpected) Match failure: "^k^" at "^(string_of_int a)^":"^(string_of_int b)))
+ | Stack_overflow -> raise (Very_bad_error ("(unexpected) Stack overflow"))
+ | _ -> raise (Very_bad_error ("(unexpected) Other error"))
+
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 16:36:56 +0000