Extended inline asm: revised treatment of clobbered registers.

- Treat clobbered registers as being destroyed by EF_inline_asm builtins
  (which is the truth, semantically).
- To enable the above, represent clobbers as Coq strings rather than idents
  and move register_by_name from Machregsaux.ml to Machregs.v.
- Side benefit: more efficient implementation of Machregsaux.name_of_register.

-# Please enter the commit message for your changes. Lines starting

17 files changed, 147 insertions, 110 deletions

diff --git a/arm/Machregs.v b/arm/Machregs.v
index f373b434..f46f2904 100644
--- a/arm/Machregs.v
+++ b/arm/Machregs.v
@@ -10,6 +10,7 @@
 (*                                                                     *)
 (* *********************************************************************)
 
+Require Import String.
 Require Import Coqlib.
 Require Import Maps.
 Require Import AST.
@@ -75,6 +76,28 @@ End IndexedMreg.
 
 Definition is_stack_reg (r: mreg) : bool := false.
 
+(** ** Names of registers *)
+
+Local Open Scope string_scope.
+
+Definition register_names :=
+  ("R0", R0) ::  ("R1", R1) ::  ("R2", R2) ::  ("R3", R3) ::
+  ("R4", R4) ::  ("R5", R5) ::  ("R6", R6) ::  ("R7", R7) ::
+  ("R8", R8) ::  ("R9", R9) ::  ("R10", R10) :: ("R11", R11) ::
+  ("R12", R12) ::
+  ("F0", F0) ::  ("F1", F1) ::  ("F2", F2) :: ("F3", F3) ::
+  ("F4", F4) ::  ("F5", F5) ::  ("F6", F6) :: ("F7", F7) ::
+  ("F8", F8) ::  ("F9", F9) ::  ("F10", F10) :: ("F11", F11) ::
+  ("F12", F12) ::("F13", F13) ::("F14", F14) :: ("F15", F15) :: nil.
+
+Definition register_by_name (s: string) : option mreg :=
+  let fix assoc (l: list (string * mreg)) : option mreg :=
+    match l with
+    | nil => None
+    | (s1, r1) :: l' => if string_dec s s1 then Some r1 else assoc l'
+    end
+  in assoc register_names.
+
 (** ** Destroyed registers, preferred registers *)
 
 Definition destroyed_by_op (op: operation): list mreg :=
@@ -95,9 +118,20 @@ Definition destroyed_by_cond (cond: condition): list mreg :=
 Definition destroyed_by_jumptable: list mreg :=
   nil.
 
+Fixpoint destroyed_by_clobber (cl: list string): list mreg :=
+  match cl with
+  | nil => nil
+  | c1 :: cl =>
+      match register_by_name c1 with
+      | Some r => r :: destroyed_by_clobber cl
+      | None   => destroyed_by_clobber cl
+      end
+  end.
+
 Definition destroyed_by_builtin (ef: external_function): list mreg :=
   match ef with
   | EF_memcpy sz al => if zle sz 32 then F7 :: nil else R2 :: R3 :: R12 :: nil
+  | EF_inline_asm txt sg clob => destroyed_by_clobber clob
   | _ => nil
   end.
 
diff --git a/arm/Machregsaux.ml b/arm/Machregsaux.ml
index 44e6b192..d59ec8b8 100644
--- a/arm/Machregsaux.ml
+++ b/arm/Machregsaux.ml
@@ -12,41 +12,24 @@
 
 (** Auxiliary functions on machine registers *)
 
+open Camlcoq
 open Machregs
 
-let register_names = [
-  ("R0", R0);  ("R1", R1);  ("R2", R2);  ("R3", R3);
-  ("R4", R4);  ("R5", R5);  ("R6", R6);  ("R7", R7);
-  ("R8", R8);  ("R9", R9);  ("R10", R10); ("R11", R11);
-  ("R12", R12);
-  ("F0", F0);  ("F1", F1);  ("F2", F2); ("F3", F3);
-  ("F4", F4);  ("F5", F5);  ("F6", F6); ("F7", F7);
-  ("F8", F8);  ("F9", F9);  ("F10", F10); ("F11", F11);
-  ("F12", F12);("F13", F13);("F14", F14); ("F15", F15)
-]
+let register_names : (mreg, string) Hashtbl.t = Hashtbl.create 31
+
+let _ =
+  List.iter
+    (fun (s, r) -> Hashtbl.add register_names r (camlstring_of_coqstring s))
+    Machregs.register_names
 
 let scratch_register_names = [ "R14" ]
 
 let name_of_register r =
-  let rec rev_assoc = function
-  | [] -> None
-  | (a, b) :: rem -> if b = r then Some a else rev_assoc rem
-  in rev_assoc register_names
+  try Some (Hashtbl.find register_names r) with Not_found -> None
 
 let register_by_name s =
-  try
-    Some(List.assoc (String.uppercase s) register_names)
-  with Not_found ->
-    None
+  Machregs.register_by_name (coqstring_of_camlstring (String.uppercase s))
 
 let can_reserve_register r =
   List.mem r Conventions1.int_callee_save_regs
   || List.mem r Conventions1.float_callee_save_regs
-
-let mregs_of_clobber idl =
-  List.fold_left
-    (fun l c ->
-      match register_by_name (Camlcoq.extern_atom c) with
-      | Some r -> r :: l
-      | None -> l)
-    [] idl
diff --git a/arm/Machregsaux.mli b/arm/Machregsaux.mli
index f0feec96..d4877a62 100644
--- a/arm/Machregsaux.mli
+++ b/arm/Machregsaux.mli
@@ -16,4 +16,3 @@ val name_of_register: Machregs.mreg -> string option
 val register_by_name: string -> Machregs.mreg option
 val scratch_register_names: string list
 val can_reserve_register: Machregs.mreg -> bool
-val mregs_of_clobber: Camlcoq.atom list -> Machregs.mreg list
diff --git a/backend/Bounds.v b/backend/Bounds.v
index 7528b66e..04c1328d 100644
--- a/backend/Bounds.v
+++ b/backend/Bounds.v
@@ -87,8 +87,6 @@ Section BOUNDS.
 
 Variable f: function.
 
-Parameter mregs_of_clobber: list ident -> list mreg.
-
 (** In the proof of the [Stacking] pass, we only need to bound the
   registers written by an instruction.  Therefore, this function
   returns these registers, ignoring registers used only as
@@ -103,7 +101,6 @@ Definition regs_of_instr (i: instruction) : list mreg :=
   | Lstore chunk addr args src => nil
   | Lcall sig ros => nil
   | Ltailcall sig ros => nil
-  | Lbuiltin (EF_inline_asm txt typs clob) args res => res ++ mregs_of_clobber clob
   | Lbuiltin ef args res => res ++ destroyed_by_builtin ef
   | Lannot ef args => nil
   | Llabel lbl => nil
@@ -354,9 +351,7 @@ Proof.
 (* call *)
   eapply size_arguments_bound; eauto.
 (* builtin *)
-  apply H1. destruct e; apply in_or_app; auto.
-  change (destroyed_by_builtin (EF_inline_asm text sg clobbers)) with (@nil mreg) in H2.
-  simpl in H2; tauto.
+  apply H1. apply in_or_app; auto.
 (* annot *)
   apply H0. rewrite slots_of_locs_charact; auto. 
 Qed.
diff --git a/backend/Regalloc.ml b/backend/Regalloc.ml
index c286e946..aa4efc53 100644
--- a/backend/Regalloc.ml
+++ b/backend/Regalloc.ml
@@ -585,13 +585,11 @@ let add_interfs_instr g instr live =
           (* like a move *)
           IRC.add_pref g arg res
       | EF_inline_asm(txt, sg, clob), _, _ ->
-          (* clobbered regs interfere with live set
-             and also with res and args for GCC compatibility *)
+          (* clobbered regs interfere with res and args for GCC compatibility *)
           List.iter (fun c ->
-            match Machregsaux.register_by_name (extern_atom c) with
+            match Machregs.register_by_name c with
             | None -> ()
             | Some mr ->
-                add_interfs_destroyed g across [mr];
                 add_interfs_list_mreg g args mr;
                 if sg.sig_res <> None then add_interfs_list_mreg g res mr)
             clob          
diff --git a/cfrontend/C2C.ml b/cfrontend/C2C.ml
index 94f13aa1..6ecdb14e 100644
--- a/cfrontend/C2C.ml
+++ b/cfrontend/C2C.ml
@@ -847,7 +847,7 @@ let convertAsm loc env txt outputs inputs clobber =
   let (txt', output', inputs') = 
     ExtendedAsm.transf_asm loc env txt outputs inputs clobber in
   let clobber' =
-    List.map intern_string clobber in
+    List.map (fun s -> coqstring_of_camlstring (String.uppercase s)) clobber in
   let ty_res =
     match output' with None -> TVoid [] | Some e -> e.etyp in
   (* Build the Ebuiltin expression *)
diff --git a/cfrontend/PrintCsyntax.ml b/cfrontend/PrintCsyntax.ml
index 39de282b..bde61cc7 100644
--- a/cfrontend/PrintCsyntax.ml
+++ b/cfrontend/PrintCsyntax.ml
@@ -299,9 +299,9 @@ and extended_asm p txt res args clob =
   begin match clob with
   | [] -> ()
   | c1 :: cl ->
-      fprintf p "@ : @[<hov 0>%S" (extern_atom c1);
+      fprintf p "@ : @[<hov 0>%S" (camlstring_of_coqstring c1);
       List.iter
-        (fun c -> fprintf p ",@ %S" (extern_atom c))
+        (fun c -> fprintf p ",@ %S" (camlstring_of_coqstring c))
         cl;
       fprintf p "@]"
   end;
diff --git a/common/AST.v b/common/AST.v
index 2550844b..08a19789 100644
--- a/common/AST.v
+++ b/common/AST.v
@@ -584,7 +584,7 @@ Inductive external_function : Type :=
      (** Another form of annotation that takes one argument, produces
          an event carrying the text and the value of this argument,
          and returns the value of the argument. *)
-  | EF_inline_asm (text: ident) (sg: signature) (clobbers: list ident).
+  | EF_inline_asm (text: ident) (sg: signature) (clobbers: list String.string).
      (** Inline [asm] statements.  Semantically, treated like an
          annotation with no parameters ([EF_annot text nil]).  To be
          used with caution, as it can invalidate the semantic
@@ -642,7 +642,7 @@ Proof.
   generalize ident_eq signature_eq chunk_eq typ_eq zeq Int.eq_dec; intros.
   decide equality.
   apply list_eq_dec. auto.
-  apply list_eq_dec. auto.
+  apply list_eq_dec. apply String.string_dec. 
 Defined.
 Global Opaque external_function_eq.
 
diff --git a/cparser/ExtendedAsm.ml b/cparser/ExtendedAsm.ml
index 94d23102..fbf8d569 100644
--- a/cparser/ExtendedAsm.ml
+++ b/cparser/ExtendedAsm.ml
@@ -161,9 +161,10 @@ let transf_outputs loc env = function
 let check_clobbers loc clob =
   List.iter
     (fun c ->
-      if Machregsaux.register_by_name c <> None
-      || List.mem c Machregsaux.scratch_register_names
-      || c = "memory" || c = "cc"
+      let c' = String.uppercase c in
+      if Machregsaux.register_by_name c' <> None
+      || List.mem c' Machregsaux.scratch_register_names
+      || c' = "MEMORY" || c' = "CC"
       then ()
       else error "%aError: unrecognized asm register clobber '%s'" 
                  formatloc loc c)
diff --git a/extraction/extraction.v b/extraction/extraction.v
index 4c400036..f7e99545 100644
--- a/extraction/extraction.v
+++ b/extraction/extraction.v
@@ -77,9 +77,6 @@ Extract Constant Allocation.regalloc => "Regalloc.regalloc".
 (* Linearize *)
 Extract Constant Linearize.enumerate_aux => "Linearizeaux.enumerate_aux".
 
-(* Bounds *)
-Extract Constant Bounds.mregs_of_clobber => "Machregsaux.mregs_of_clobber".
-
 (* SimplExpr *)
 Extract Constant SimplExpr.first_unused_ident => "Camlcoq.first_unused_ident".
 Extraction Inline SimplExpr.ret SimplExpr.error SimplExpr.bind SimplExpr.bind2.
diff --git a/ia32/Machregs.v b/ia32/Machregs.v
index a9f2b6c4..65e27599 100644
--- a/ia32/Machregs.v
+++ b/ia32/Machregs.v
@@ -69,6 +69,25 @@ End IndexedMreg.
 Definition is_stack_reg (r: mreg) : bool :=
   match r with FP0 => true | _ => false end.
 
+(** ** Names of registers *)
+
+Local Open Scope string_scope.
+
+Definition register_names :=
+  ("EAX", AX) :: ("EBX", BX) :: ("ECX", CX) :: ("EDX", DX) ::
+  ("ESI", SI) :: ("EDI", DI) :: ("EBP", BP) ::
+  ("XMM0", X0) :: ("XMM1", X1) :: ("XMM2", X2) :: ("XMM3", X3) ::
+  ("XMM4", X4) :: ("XMM5", X5) :: ("XMM6", X6) :: ("XMM7", X7) ::
+  ("ST0", FP0) :: nil.
+
+Definition register_by_name (s: string) : option mreg :=
+  let fix assoc (l: list (string * mreg)) : option mreg :=
+    match l with
+    | nil => None
+    | (s1, r1) :: l' => if string_dec s s1 then Some r1 else assoc l'
+    end
+  in assoc register_names.
+
 (** ** Destroyed registers, preferred registers *)
 
 Definition destroyed_by_op (op: operation): list mreg :=
@@ -100,7 +119,15 @@ Definition destroyed_by_cond (cond: condition): list mreg :=
 Definition destroyed_by_jumptable: list mreg :=
   nil.
 
-Local Open Scope string_scope.
+Fixpoint destroyed_by_clobber (cl: list string): list mreg :=
+  match cl with
+  | nil => nil
+  | c1 :: cl =>
+      match register_by_name c1 with
+      | Some r => r :: destroyed_by_clobber cl
+      | None   => destroyed_by_clobber cl
+      end
+  end.
 
 Definition builtin_write16_reversed := ident_of_string "__builtin_write16_reversed".
 Definition builtin_write32_reversed := ident_of_string "__builtin_write32_reversed".
@@ -115,6 +142,7 @@ Definition destroyed_by_builtin (ef: external_function): list mreg :=
       if ident_eq id builtin_write16_reversed
       || ident_eq id builtin_write32_reversed
       then CX :: DX :: nil else nil
+  | EF_inline_asm txt sg clob => destroyed_by_clobber clob
   | _ => nil
   end.
 
diff --git a/ia32/Machregsaux.ml b/ia32/Machregsaux.ml
index 5e98b58b..6485e752 100644
--- a/ia32/Machregsaux.ml
+++ b/ia32/Machregsaux.ml
@@ -12,38 +12,25 @@
 
 (** Auxiliary functions on machine registers *)
 
+open Camlcoq
 open Machregs
 
-let register_names = [
-  ("EAX", AX); ("EBX", BX); ("ECX", CX); ("EDX", DX);
-  ("ESI", SI); ("EDI", DI); ("EBP", BP);
-  ("XMM0", X0); ("XMM1", X1); ("XMM2", X2); ("XMM3", X3);
-  ("XMM4", X4); ("XMM5", X5); ("XMM6", X6); ("XMM7", X7);
-  ("ST0", FP0)
-]
+let register_names : (mreg, string) Hashtbl.t = Hashtbl.create 31
+
+let _ =
+  List.iter
+    (fun (s, r) -> Hashtbl.add register_names r (camlstring_of_coqstring s))
+    Machregs.register_names
 
 let scratch_register_names = []
 
 let name_of_register r =
-  let rec rev_assoc = function
-  | [] -> None
-  | (a, b) :: rem -> if b = r then Some a else rev_assoc rem
-  in rev_assoc register_names
+  try Some (Hashtbl.find register_names r) with Not_found -> None
 
 let register_by_name s =
-  try
-    Some(List.assoc (String.uppercase s) register_names)
-  with Not_found ->
-    None
+  Machregs.register_by_name (coqstring_of_camlstring (String.uppercase s))
 
 let can_reserve_register r =
   List.mem r Conventions1.int_callee_save_regs
   || List.mem r Conventions1.float_callee_save_regs
 
-let mregs_of_clobber idl =
-  List.fold_left
-    (fun l c ->
-      match register_by_name (Camlcoq.extern_atom c) with
-      | Some r -> r :: l
-      | None -> l)
-    [] idl
diff --git a/ia32/Machregsaux.mli b/ia32/Machregsaux.mli
index f0feec96..d4877a62 100644
--- a/ia32/Machregsaux.mli
+++ b/ia32/Machregsaux.mli
@@ -16,4 +16,3 @@ val name_of_register: Machregs.mreg -> string option
 val register_by_name: string -> Machregs.mreg option
 val scratch_register_names: string list
 val can_reserve_register: Machregs.mreg -> bool
-val mregs_of_clobber: Camlcoq.atom list -> Machregs.mreg list
diff --git a/powerpc/Machregs.v b/powerpc/Machregs.v
index f7ed7793..3b7cbb76 100644
--- a/powerpc/Machregs.v
+++ b/powerpc/Machregs.v
@@ -10,6 +10,7 @@
 (*                                                                     *)
 (* *********************************************************************)
 
+Require Import String.
 Require Import Coqlib.
 Require Import Maps.
 Require Import AST.
@@ -97,6 +98,36 @@ End IndexedMreg.
 
 Definition is_stack_reg (r: mreg) : bool := false.
 
+(** ** Names of registers *)
+
+Local Open Scope string_scope.
+
+Definition register_names :=
+  ("R3", R3) ::  ("R4", R4) ::  ("R5", R5) ::  ("R6", R6) ::
+  ("R7", R7) ::  ("R8", R8) ::  ("R9", R9) ::  ("R10", R10) ::
+  ("R11", R11) :: ("R12", R12) ::
+  ("R14", R14) :: ("R15", R15) :: ("R16", R16) ::
+  ("R17", R17) :: ("R18", R18) :: ("R19", R19) :: ("R20", R20) ::
+  ("R21", R21) :: ("R22", R22) :: ("R23", R23) :: ("R24", R24) ::
+  ("R25", R25) :: ("R26", R26) :: ("R27", R27) :: ("R28", R28) ::
+  ("R29", R29) :: ("R30", R30) :: ("R31", R31) ::
+  ("F0", F0) :: ("F1", F1) ::  ("F2", F2) ::  ("F3", F3) ::  ("F4", F4) ::
+  ("F5", F5) ::  ("F6", F6) ::  ("F7", F7) ::  ("F8", F8) ::
+  ("F9", F9) ::  ("F10", F10) :: ("F11", F11) :: ("F12", F12) ::
+  ("F13", F13) :: ("F14", F14) :: ("F15", F15) ::
+  ("F16", F16) :: ("F17", F17) :: ("F18", F18) :: ("F19", F19) ::
+  ("F20", F20) :: ("F21", F21) :: ("F22", F22) :: ("F23", F23) ::
+  ("F24", F24) :: ("F25", F25) :: ("F26", F26) :: ("F27", F27) ::
+  ("F28", F28) :: ("F29", F29) :: ("F30", F30) :: ("F31", F31) :: nil.
+
+Definition register_by_name (s: string) : option mreg :=
+  let fix assoc (l: list (string * mreg)) : option mreg :=
+    match l with
+    | nil => None
+    | (s1, r1) :: l' => if string_dec s s1 then Some r1 else assoc l'
+    end
+  in assoc register_names.
+
 (** ** Destroyed registers, preferred registers *)
 
 Definition destroyed_by_op (op: operation): list mreg :=
@@ -119,6 +150,16 @@ Definition destroyed_by_cond (cond: condition): list mreg :=
 Definition destroyed_by_jumptable: list mreg :=
   R12 :: nil.
 
+Fixpoint destroyed_by_clobber (cl: list string): list mreg :=
+  match cl with
+  | nil => nil
+  | c1 :: cl =>
+      match register_by_name c1 with
+      | Some r => r :: destroyed_by_clobber cl
+      | None   => destroyed_by_clobber cl
+      end
+  end.
+
 Definition destroyed_by_builtin (ef: external_function): list mreg :=
   match ef with
   | EF_builtin _ _ => F13 :: nil
@@ -128,6 +169,7 @@ Definition destroyed_by_builtin (ef: external_function): list mreg :=
   | EF_vstore_global Mint64 _ _ => R10 :: R11 :: R12 :: nil
   | EF_vstore_global _ _ _ => R11 :: R12 :: nil
   | EF_memcpy _ _ => R11 :: R12 :: F13 :: nil
+  | EF_inline_asm txt sg clob => destroyed_by_clobber clob
   | _ => nil
   end.
 
diff --git a/powerpc/Machregsaux.ml b/powerpc/Machregsaux.ml
index ba111089..8c3017ff 100644
--- a/powerpc/Machregsaux.ml
+++ b/powerpc/Machregsaux.ml
@@ -12,49 +12,24 @@
 
 (** Auxiliary functions on machine registers *)
 
+open Camlcoq
 open Machregs
 
-let register_names = [
-  ("R3", R3);  ("R4", R4);  ("R5", R5);  ("R6", R6);
-  ("R7", R7);  ("R8", R8);  ("R9", R9);  ("R10", R10);
-  ("R11", R11); ("R12", R12);
-  ("R14", R14); ("R15", R15); ("R16", R16);
-  ("R17", R17); ("R18", R18); ("R19", R19); ("R20", R20);
-  ("R21", R21); ("R22", R22); ("R23", R23); ("R24", R24);
-  ("R25", R25); ("R26", R26); ("R27", R27); ("R28", R28);
-  ("R29", R29); ("R30", R30); ("R31", R31);
-  ("F0", F0); ("F1", F1);  ("F2", F2);  ("F3", F3);  ("F4", F4);
-  ("F5", F5);  ("F6", F6);  ("F7", F7);  ("F8", F8);
-  ("F9", F9);  ("F10", F10); ("F11", F11); ("F12", F12);
-  ("F13", F13); ("F14", F14); ("F15", F15);
-  ("F16", F16); ("F17", F17); ("F18", F18); ("F19", F19);
-  ("F20", F20); ("F21", F21); ("F22", F22); ("F23", F23);
-  ("F24", F24); ("F25", F25); ("F26", F26); ("F27", F27);
-  ("F28", F28); ("F29", F29); ("F30", F30); ("F31", F31)
-]
+let register_names : (mreg, string) Hashtbl.t = Hashtbl.create 31
+
+let _ =
+  List.iter
+    (fun (s, r) -> Hashtbl.add register_names r (camlstring_of_coqstring s))
+    Machregs.register_names
 
 let scratch_register_names = [ "R0" ]
 
 let name_of_register r =
-  let rec rev_assoc = function
-  | [] -> None
-  | (a, b) :: rem -> if b = r then Some a else rev_assoc rem
-  in rev_assoc register_names
+  try Some (Hashtbl.find register_names r) with Not_found -> None
 
 let register_by_name s =
-  try
-    Some(List.assoc (String.uppercase s) register_names)
-  with Not_found ->
-    None
+  Machregs.register_by_name (coqstring_of_camlstring (String.uppercase s))
 
 let can_reserve_register r =
   List.mem r Conventions1.int_callee_save_regs
   || List.mem r Conventions1.float_callee_save_regs
-
-let mregs_of_clobber idl =
-  List.fold_left
-    (fun l c ->
-      match register_by_name (Camlcoq.extern_atom c) with
-      | Some r -> r :: l
-      | None -> l)
-    [] idl
diff --git a/powerpc/Machregsaux.mli b/powerpc/Machregsaux.mli
index f0feec96..d4877a62 100644
--- a/powerpc/Machregsaux.mli
+++ b/powerpc/Machregsaux.mli
@@ -16,4 +16,3 @@ val name_of_register: Machregs.mreg -> string option
 val register_by_name: string -> Machregs.mreg option
 val scratch_register_names: string list
 val can_reserve_register: Machregs.mreg -> bool
-val mregs_of_clobber: Camlcoq.atom list -> Machregs.mreg list
diff --git a/test/regression/extasm.c b/test/regression/extasm.c
index 4925392e..00a1cd57 100644
--- a/test/regression/extasm.c
+++ b/test/regression/extasm.c
@@ -1,7 +1,7 @@
 /* Testing extended asm.
    To run the test, compile with -S and grep "TEST" in the generated .s */
 
-int clobbers(int x)
+int clobbers(int x, int z)
 {
   int y;
   asm("TEST0 out:%0 in:%1" : "=r"(y) : "r"(x) : "cc"
@@ -10,10 +10,10 @@ int clobbers(int x)
 #elif defined(__arm__)
       , "r0", "r1", "r4"
 #elif defined(__PPC__)
-      , "r3", "r4", "r31"
+      , "r0", "r3", "r4", "r31"
 #endif
 );
-  return y;
+  return y + z;
 }
 
 int main()