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

3 files changed, 43 insertions, 27 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