2 files changed, 816 insertions, 0 deletions

diff --git a/src/boot/util/bits.ml b/src/boot/util/bits.ml
new file mode 100644
index 00000000..3114bd66
--- /dev/null
+++ b/src/boot/util/bits.ml
@@ -0,0 +1,107 @@
+type t = {
+  storage: int array;
+  nbits: int;
+}
+;;
+
+let int_bits =
+  if max_int = (1 lsl 30) - 1
+  then 31
+  else 63
+;;
+
+let create nbits flag =
+  { storage = Array.make (nbits / int_bits + 1) (if flag then lnot 0 else 0);
+    nbits = nbits }
+;;
+
+(* 
+ * mutate v0 in place: v0.(i) <- v0.(i) op v1.(i), returning bool indicating
+ * whether any bits in v0 changed in the process. 
+ *)
+let process (op:int -> int -> int) (v0:t) (v1:t) : bool =
+  let changed = ref false in
+    assert (v0.nbits = v1.nbits);
+    assert ((Array.length v0.storage) = (Array.length v1.storage));
+    Array.iteri
+      begin
+        fun i w1 ->
+          let w0 = v0.storage.(i) in
+          let w0' = op w0 w1 in
+            if not (w0' = w0)
+            then changed := true;
+            v0.storage.(i) <- w0';
+      end
+      v1.storage;
+    !changed
+;;
+
+let union = process (lor) ;;
+let intersect = process (land) ;;
+let copy = process (fun _ w1 -> w1) ;;
+
+let get (v:t) (i:int) : bool =
+  assert (i >= 0);
+  assert (i < v.nbits);
+  let w = i / int_bits in
+  let b = i mod int_bits in
+  let x = 1 land (v.storage.(w) lsr b) in
+    x = 1
+;;
+
+let equal (v1:t) (v0:t) : bool =
+  v0 = v1
+;;
+
+let clear (v:t) : unit =
+  for i = 0 to (Array.length v.storage) - 1
+  do
+    v.storage.(i) <- 0
+  done
+;;
+
+let invert (v:t) : unit =
+  for i = 0 to (Array.length v.storage) - 1
+  do
+    v.storage.(i) <- lnot v.storage.(i)
+  done
+;;
+
+let set (v:t) (i:int) (x:bool) : unit =
+  assert (i >= 0);
+  assert (i < v.nbits);
+  let w = i / int_bits in
+  let b = i mod int_bits in
+  let w0 = v.storage.(w) in
+  let flag = 1 lsl b in
+    v.storage.(w) <-
+      if x
+      then w0 lor flag
+      else w0 land (lnot flag)
+;;
+
+let to_list (v:t) : int list =
+  if v.nbits = 0
+  then []
+  else
+    let accum = ref [] in
+    let word = ref v.storage.(0) in
+      for i = 0 to (v.nbits-1) do
+        if i mod int_bits = 0
+        then word := v.storage.(i / int_bits);
+        if (1 land (!word)) = 1
+        then accum := i :: (!accum);
+        word := (!word) lsr 1;
+      done;
+      !accum
+;;
+
+
+(*
+ * Local Variables:
+ * fill-column: 78;
+ * indent-tabs-mode: nil
+ * buffer-file-coding-system: utf-8-unix
+ * compile-command: "make -k -C ../.. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+ * End:
+ *)
diff --git a/src/boot/util/common.ml b/src/boot/util/common.ml
new file mode 100644
index 00000000..f33a6ea1
--- /dev/null
+++ b/src/boot/util/common.ml
@@ -0,0 +1,709 @@
+(*
+ * This module goes near the *bottom* of the dependency DAG, and holds basic
+ * types shared across all phases of the compiler.
+ *)
+
+type filename = string
+type pos = (filename * int * int)
+type span = {lo: pos; hi: pos}
+
+type node_id = Node of int
+type temp_id = Temp of int
+type opaque_id = Opaque of int
+type constr_id = Constr of int
+
+let int_of_node (Node i) = i
+let int_of_temp (Temp i) = i
+let int_of_opaque (Opaque i) = i
+let int_of_constr (Constr i) = i
+
+type 'a identified = { node: 'a; id: node_id }
+;;
+
+let bug _ =
+  let k s = failwith s
+  in Printf.ksprintf k
+;;
+
+exception Semant_err of ((node_id option) * string)
+;;
+
+let err (idopt:node_id option) =
+  let k s =
+    raise (Semant_err (idopt, s))
+  in
+    Printf.ksprintf k
+;;
+
+(* Some ubiquitous low-level types. *)
+
+type target =
+    Linux_x86_elf
+  | Win32_x86_pe
+  | MacOS_x86_macho
+;;
+
+type ty_mach =
+    TY_u8
+  | TY_u16
+  | TY_u32
+  | TY_u64
+  | TY_i8
+  | TY_i16
+  | TY_i32
+  | TY_i64
+  | TY_f32
+  | TY_f64
+;;
+
+let mach_is_integral (mach:ty_mach) : bool =
+  match mach with
+      TY_i8 | TY_i16 | TY_i32 | TY_i64
+    | TY_u8 | TY_u16 | TY_u32 | TY_u64 -> true
+    | TY_f32 | TY_f64 -> false
+;;
+
+
+let mach_is_signed (mach:ty_mach) : bool =
+  match mach with
+      TY_i8 | TY_i16 | TY_i32 | TY_i64 -> true
+    | TY_u8 | TY_u16 | TY_u32 | TY_u64
+    | TY_f32 | TY_f64 -> false
+;;
+
+let string_of_ty_mach (mach:ty_mach) : string =
+  match mach with
+    TY_u8 -> "u8"
+  | TY_u16 -> "u16"
+  | TY_u32 -> "u32"
+  | TY_u64 -> "u64"
+  | TY_i8 -> "i8"
+  | TY_i16 -> "i16"
+  | TY_i32 -> "i32"
+  | TY_i64 -> "i64"
+  | TY_f32 -> "f32"
+  | TY_f64 -> "f64"
+;;
+
+let bytes_of_ty_mach (mach:ty_mach) : int =
+  match mach with
+    TY_u8 -> 1
+  | TY_u16 -> 2
+  | TY_u32 -> 4
+  | TY_u64 -> 8
+  | TY_i8 -> 1
+  | TY_i16 -> 2
+  | TY_i32 -> 4
+  | TY_i64 -> 8
+  | TY_f32 -> 4
+  | TY_f64 -> 8
+;;
+
+type ty_param_idx = int
+;;
+
+type nabi_conv =
+    CONV_rust
+  | CONV_cdecl
+;;
+
+type nabi = { nabi_indirect: bool;
+              nabi_convention: nabi_conv }
+;;
+
+let string_to_conv (a:string) : nabi_conv option =
+  match a with
+      "cdecl" -> Some CONV_cdecl
+    | "rust" -> Some CONV_rust
+    | _ -> None
+
+(* FIXME: remove this when native items go away. *)
+let string_to_nabi (s:string) (indirect:bool) : nabi option =
+  match string_to_conv s with
+      None -> None
+    | Some c ->
+        Some { nabi_indirect = indirect;
+               nabi_convention = c }
+;;
+
+type required_lib_spec =
+    {
+      required_libname: string;
+      required_prefix: int;
+    }
+;;
+
+type required_lib =
+    REQUIRED_LIB_rustrt
+  | REQUIRED_LIB_crt
+  | REQUIRED_LIB_rust of required_lib_spec
+  | REQUIRED_LIB_c of required_lib_spec
+;;
+
+type segment =
+    SEG_text
+  | SEG_data
+;;
+
+type fixup =
+    { fixup_name: string;
+      mutable fixup_file_pos: int option;
+      mutable fixup_file_sz: int option;
+      mutable fixup_mem_pos: int64 option;
+      mutable fixup_mem_sz: int64 option }
+;;
+
+
+let new_fixup (s:string)
+    : fixup =
+  { fixup_name = s;
+    fixup_file_pos = None;
+    fixup_file_sz = None;
+    fixup_mem_pos = None;
+    fixup_mem_sz = None }
+;;
+
+
+(*
+ * Auxiliary hashtable functions.
+ *)
+
+let htab_keys (htab:('a,'b) Hashtbl.t) : ('a list) =
+  Hashtbl.fold (fun k _ accum -> k :: accum) htab []
+;;
+
+let sorted_htab_keys (tab:('a, 'b) Hashtbl.t) : 'a array =
+  let keys = Array.of_list (htab_keys tab) in
+    Array.sort compare keys;
+    keys
+;;
+
+let htab_vals (htab:('a,'b) Hashtbl.t) : ('b list)  =
+  Hashtbl.fold (fun _ v accum -> v :: accum) htab []
+;;
+
+let htab_pairs (htab:('a,'b) Hashtbl.t) : (('a * 'b) list) =
+  Hashtbl.fold (fun k v accum -> (k,v) :: accum) htab []
+;;
+
+let htab_search (htab:('a,'b) Hashtbl.t) (k:'a) : ('b option) =
+  if Hashtbl.mem htab k
+  then Some (Hashtbl.find htab k)
+  else None
+;;
+
+let htab_search_or_default
+    (htab:('a,'b) Hashtbl.t)
+    (k:'a)
+    (def:unit -> 'b)
+    : 'b =
+  match htab_search htab k with
+      Some v -> v
+    | None -> def()
+;;
+
+let htab_search_or_add
+    (htab:('a,'b) Hashtbl.t)
+    (k:'a)
+    (mk:unit -> 'b)
+    : 'b =
+  let def () =
+    let v = mk() in
+      Hashtbl.add htab k v;
+      v
+  in
+    htab_search_or_default htab k def
+;;
+
+let htab_put (htab:('a,'b) Hashtbl.t) (a:'a) (b:'b) : unit =
+  assert (not (Hashtbl.mem htab a));
+  Hashtbl.add htab a b
+;;
+
+let htab_map
+    (htab:('a,'b) Hashtbl.t)
+    (f:'a -> 'b -> ('c * 'd))
+    : (('c,'d) Hashtbl.t) =
+  let ntab = Hashtbl.create (Hashtbl.length htab) in
+  let g a b =
+    let (c,d) = f a b in
+      htab_put ntab c d
+  in
+    Hashtbl.iter g htab;
+    ntab
+;;
+
+
+let htab_fold
+    (fn:'a -> 'b -> 'c -> 'c)
+    (init:'c)
+    (h:('a, 'b) Hashtbl.t) : 'c =
+  let accum = ref init in
+  let f a b = accum := (fn a b (!accum)) in
+    Hashtbl.iter f h;
+    !accum
+;;
+
+
+let reduce_hash_to_list
+    (fn:'a -> 'b -> 'c)
+    (h:('a, 'b) Hashtbl.t)
+    : ('c list) =
+  htab_fold (fun a b ls -> (fn a b) :: ls) [] h
+;;
+
+(* 
+ * Auxiliary association-array and association-list operations.
+ *)
+let atab_search (atab:('a * 'b) array) (a:'a) : ('b option) =
+  let lim = Array.length atab in
+  let rec step i =
+    if i = lim
+    then None
+    else
+      let (k,v) = atab.(i) in
+        if k = a
+        then Some v
+        else step (i+1)
+  in
+    step 0
+
+let atab_find (atab:('a * 'b) array) (a:'a) : 'b =
+  match atab_search atab a with
+      None -> bug () "atab_find: element not found"
+    | Some b -> b
+
+let atab_mem (atab:('a * 'b) array) (a:'a) : bool =
+  match atab_search atab a with
+      None -> false
+    | Some _ -> true
+
+let rec ltab_search (ltab:('a * 'b) list) (a:'a) : ('b option) =
+  match ltab with
+      [] -> None
+    | (k,v)::_ when k = a -> Some v
+    | _::lz -> ltab_search lz a
+
+let ltab_put (ltab:('a * 'b) list) (a:'a) (b:'b) : (('a * 'b) list) =
+  assert ((ltab_search ltab a) = None);
+  (a,b)::ltab
+
+(*
+ * Auxiliary list functions.
+ *)
+
+let rec list_search (list:'a list) (f:'a -> 'b option) : ('b option) =
+  match list with
+      [] -> None
+    | a::az ->
+        match f a with
+            Some b -> Some b
+          | None -> list_search az f
+
+let rec list_search_ctxt
+    (list:'a list)
+    (f:'a -> 'b option)
+    : ((('a list) * 'b) option) =
+  match list with
+      [] -> None
+    | a::az ->
+        match f a with
+            Some b -> Some (list, b)
+          | None -> list_search_ctxt az f
+
+let rec list_drop n ls =
+  if n = 0
+  then ls
+  else list_drop (n-1) (List.tl ls)
+;;
+
+
+(*
+ * Auxiliary option functions.
+ *)
+
+let bool_of_option x =
+  match x with
+      Some _ -> true
+    | None -> false
+
+
+(*
+ * Auxiliary stack functions.
+ *)
+
+let stk_fold (s:'a Stack.t) (f:'a -> 'b -> 'b) (x:'b) : 'b =
+  let r = ref x in
+    Stack.iter (fun e -> r := f e (!r)) s;
+    !r
+
+let stk_elts_from_bot (s:'a Stack.t) : ('a list) =
+  stk_fold s (fun x y -> x::y) []
+
+let stk_elts_from_top (s:'a Stack.t) : ('a list) =
+  List.rev (stk_elts_from_bot s)
+
+let stk_search (s:'a Stack.t) (f:'a -> 'b option) : 'b option =
+  stk_fold s (fun e accum -> match accum with None -> (f e) | x -> x) None
+
+
+(*
+ * Auxiliary array functions.
+ *)
+
+let arr_search (a:'a array) (f:int -> 'a -> 'b option) : 'b option =
+  let max = Array.length a in
+  let rec iter i =
+    if i < max
+    then
+      let v = a.(i) in
+      let r = f i v in
+        match r with
+            Some _ -> r
+          | None -> iter (i+1)
+    else
+      None
+  in
+    iter 0
+;;
+
+let arr_idx (arr:'a array) (a:'a) : int =
+  let find i v = if v = a then Some i else None in
+    match arr_search arr find with
+        None -> bug () "arr_idx: element not found"
+      | Some i -> i
+;;
+
+let arr_map_partial (a:'a array) (f:'a -> 'b option) : 'b array =
+  let accum a ls =
+    match f a with
+        None -> ls
+      | Some b -> b :: ls
+  in
+    Array.of_list (Array.fold_right accum a [])
+;;
+
+let arr_filter_some (a:'a option array) : 'a array =
+  arr_map_partial a (fun x -> x)
+;;
+
+let arr_find_dups (a:'a array) : ('a * 'a) option =
+  let copy = Array.copy a in
+    Array.sort compare copy;
+    let lasti = (Array.length copy) - 1 in
+    let rec find_dups i =
+      if i < lasti then
+        let this = copy.(i) in
+        let next = copy.(i+1) in
+          (if (this = next) then
+             Some (this, next)
+           else
+             find_dups (i+1))
+      else
+        None
+    in
+      find_dups 0
+;;
+
+let arr_check_dups (a:'a array) (f:'a -> 'a -> unit) : unit =
+  match arr_find_dups a with
+      Some (x, y) -> f x y
+    | None -> ()
+;;
+
+let arr_map2 (f:'a -> 'b -> 'c) (a:'a array) (b:'b array) : 'c array =
+  assert ((Array.length a) = (Array.length b));
+  Array.init (Array.length a) (fun i -> f a.(i) b.(i))
+;;
+
+let arr_for_all (f:int -> 'a -> bool) (a:'a array) : bool =
+  let len = Array.length a in
+  let rec loop i =
+    (i >= len) || ((f i a.(i)) && (loop (i+1)))
+  in
+    loop 0
+;;
+
+let arr_exists (f:int -> 'a -> bool) (a:'a array) : bool =
+  let len = Array.length a in
+  let rec loop i =
+    (i < len) && ((f i a.(i)) || (loop (i+1)))
+  in
+    loop 0
+;;
+
+(* 
+ * Auxiliary queue functions. 
+ *)
+
+let queue_to_list (q:'a Queue.t) : 'a list =
+  List.rev (Queue.fold (fun ls elt -> elt :: ls)  []  q)
+;;
+
+let queue_to_arr (q:'a Queue.t) : 'a array =
+  Array.init (Queue.length q) (fun _ -> Queue.take q)
+;;
+
+(*
+ * Auxiliary int64 functions
+ *)
+
+let i64_lt (a:int64) (b:int64) : bool = (Int64.compare a b) < 0
+let i64_le (a:int64) (b:int64) : bool = (Int64.compare a b) <= 0
+let i64_ge (a:int64) (b:int64) : bool = (Int64.compare a b) >= 0
+let i64_gt (a:int64) (b:int64) : bool = (Int64.compare a b) > 0
+let i64_max (a:int64) (b:int64) : int64 =
+  (if (Int64.compare a b) > 0 then a else b)
+let i64_min (a:int64) (b:int64) : int64 =
+  (if (Int64.compare a b) < 0 then a else b)
+let i64_align (align:int64) (v:int64) : int64 =
+  (assert (align <> 0L));
+  let mask = Int64.sub align 1L in
+    Int64.logand (Int64.lognot mask) (Int64.add v mask)
+;;
+
+let rec i64_for (lo:int64) (hi:int64) (thunk:int64 -> unit) : unit =
+  if i64_lt lo hi then
+    begin
+      thunk lo;
+      i64_for (Int64.add lo 1L) hi thunk;
+    end
+;;
+
+let rec i64_for_rev (hi:int64) (lo:int64) (thunk:int64 -> unit) : unit =
+  if i64_ge hi lo then
+    begin
+      thunk hi;
+      i64_for_rev (Int64.sub hi 1L) lo thunk;
+    end
+;;
+
+
+(*
+ * Auxiliary int32 functions
+ *)
+
+let i32_lt (a:int32) (b:int32) : bool = (Int32.compare a b) < 0
+let i32_le (a:int32) (b:int32) : bool = (Int32.compare a b) <= 0
+let i32_ge (a:int32) (b:int32) : bool = (Int32.compare a b) >= 0
+let i32_gt (a:int32) (b:int32) : bool = (Int32.compare a b) > 0
+let i32_max (a:int32) (b:int32) : int32 =
+  (if (Int32.compare a b) > 0 then a else b)
+let i32_min (a:int32) (b:int32) : int32 =
+  (if (Int32.compare a b) < 0 then a else b)
+let i32_align (align:int32) (v:int32) : int32 =
+  (assert (align <> 0l));
+  let mask = Int32.sub align 1l in
+    Int32.logand (Int32.lognot mask) (Int32.add v mask)
+;;
+
+(*
+ * Int-as-unichar functions.
+ *)
+
+let bounds lo c hi = (lo <= c) && (c <= hi)
+;;
+
+let escaped_char i =
+  if bounds 0 i 0x7f
+  then Char.escaped (Char.chr i)
+  else
+    if bounds 0 i 0xffff
+    then Printf.sprintf "\\u%4.4X" i
+    else Printf.sprintf "\\U%8.8X" i
+;;
+
+let char_as_utf8 i =
+  let buf = Buffer.create 8 in
+  let addb i =
+    Buffer.add_char buf (Char.chr (i land 0xff))
+  in
+  let fini _ =
+    Buffer.contents buf
+  in
+  let rec add_trailing_bytes n i =
+    if n = 0
+    then fini()
+    else
+      begin
+        addb (0b1000_0000 lor ((i lsr ((n-1) * 6)) land 0b11_1111));
+        add_trailing_bytes (n-1) i
+      end
+  in
+    if bounds 0 i 0x7f
+    then (addb i; fini())
+    else
+      if bounds 0x80 i 0x7ff
+      then (addb ((0b1100_0000) lor (i lsr 6));
+            add_trailing_bytes 1 i)
+      else
+        if bounds 0x800 i 0xffff
+        then (addb ((0b1110_0000) lor (i lsr 12));
+              add_trailing_bytes 2 i)
+        else
+          if bounds 0x1000 i 0x1f_ffff
+          then (addb ((0b1111_0000) lor (i lsr 18));
+                add_trailing_bytes 3 i)
+          else
+            if bounds 0x20_0000 i 0x3ff_ffff
+            then (addb ((0b1111_1000) lor (i lsr 24));
+                  add_trailing_bytes 4 i)
+            else
+              if bounds 0x400_0000 i 0x7fff_ffff
+              then (addb ((0b1111_1100) lor (i lsr 30));
+                    add_trailing_bytes 5 i)
+              else bug () "bad unicode character 0x%X" i
+;;
+
+(*
+ * Size-expressions.
+ *)
+
+
+type size =
+    SIZE_fixed of int64
+  | SIZE_fixup_mem_sz of fixup
+  | SIZE_fixup_mem_pos of fixup
+  | SIZE_param_size of ty_param_idx
+  | SIZE_param_align of ty_param_idx
+  | SIZE_rt_neg of size
+  | SIZE_rt_add of size * size
+  | SIZE_rt_mul of size * size
+  | SIZE_rt_max of size * size
+  | SIZE_rt_align of size * size
+;;
+
+let rec string_of_size (s:size) : string =
+  match s with
+      SIZE_fixed i -> Printf.sprintf "%Ld" i
+    | SIZE_fixup_mem_sz f -> Printf.sprintf "%s.mem_sz" f.fixup_name
+    | SIZE_fixup_mem_pos f -> Printf.sprintf "%s.mem_pos" f.fixup_name
+    | SIZE_param_size i -> Printf.sprintf "ty[%d].size" i
+    | SIZE_param_align i -> Printf.sprintf "ty[%d].align" i
+    | SIZE_rt_neg a ->
+        Printf.sprintf "-(%s)" (string_of_size a)
+    | SIZE_rt_add (a, b) ->
+        Printf.sprintf "(%s + %s)" (string_of_size a) (string_of_size b)
+    | SIZE_rt_mul (a, b) ->
+        Printf.sprintf "(%s * %s)" (string_of_size a) (string_of_size b)
+    | SIZE_rt_max (a, b) ->
+        Printf.sprintf "max(%s,%s)" (string_of_size a) (string_of_size b)
+    | SIZE_rt_align (align, off) ->
+        Printf.sprintf "align(%s,%s)"
+          (string_of_size align) (string_of_size off)
+;;
+
+let neg_sz (a:size) : size =
+  match a with
+      SIZE_fixed a -> SIZE_fixed (Int64.neg a)
+    | _ -> SIZE_rt_neg a
+;;
+
+let add_sz (a:size) (b:size) : size =
+  match (a, b) with
+      (SIZE_fixed a, SIZE_fixed b) -> SIZE_fixed (Int64.add a b)
+
+    | ((SIZE_rt_add ((SIZE_fixed a), c)), SIZE_fixed b)
+    | ((SIZE_rt_add (c, (SIZE_fixed a))), SIZE_fixed b)
+    | (SIZE_fixed a, (SIZE_rt_add ((SIZE_fixed b), c)))
+    | (SIZE_fixed a, (SIZE_rt_add (c, (SIZE_fixed b)))) ->
+        SIZE_rt_add (SIZE_fixed (Int64.add a b), c)
+
+    | (SIZE_fixed 0L, b) -> b
+    | (a, SIZE_fixed 0L) -> a
+    | (a, SIZE_fixed b) -> SIZE_rt_add (SIZE_fixed b, a)
+    | (a, b) -> SIZE_rt_add (a, b)
+;;
+
+let mul_sz (a:size) (b:size) : size =
+  match (a, b) with
+      (SIZE_fixed a, SIZE_fixed b) -> SIZE_fixed (Int64.mul a b)
+    | (a, SIZE_fixed b) -> SIZE_rt_mul (SIZE_fixed b, a)
+    | (a, b) -> SIZE_rt_mul (a, b)
+;;
+
+let rec max_sz (a:size) (b:size) : size =
+  let rec no_negs x =
+    match x with
+        SIZE_fixed _
+      | SIZE_fixup_mem_sz _
+      | SIZE_fixup_mem_pos _
+      | SIZE_param_size _
+      | SIZE_param_align _ -> true
+      | SIZE_rt_neg _ -> false
+      | SIZE_rt_add (a,b) -> (no_negs a) && (no_negs b)
+      | SIZE_rt_mul (a,b) -> (no_negs a) && (no_negs b)
+      | SIZE_rt_max (a,b) -> (no_negs a) && (no_negs b)
+      | SIZE_rt_align (a,b) -> (no_negs a) && (no_negs b)
+  in
+    match (a, b) with
+        (SIZE_rt_align _, SIZE_fixed 1L) -> a
+      | (SIZE_fixed 1L, SIZE_rt_align _) -> b
+      | (SIZE_param_align _, SIZE_fixed 1L) -> a
+      | (SIZE_fixed 1L, SIZE_param_align _) -> b
+      | (a, SIZE_rt_max (b, c)) when a = b -> max_sz a c
+      | (a, SIZE_rt_max (b, c)) when a = c -> max_sz a b
+      | (SIZE_rt_max (b, c), a) when a = b -> max_sz a c
+      | (SIZE_rt_max (b, c), a) when a = c -> max_sz a b
+      | (SIZE_fixed a, SIZE_fixed b) -> SIZE_fixed (i64_max a b)
+      | (SIZE_fixed 0L, b) when no_negs b -> b
+      | (a, SIZE_fixed 0L) when no_negs a -> b
+      | (a, SIZE_fixed b) -> max_sz (SIZE_fixed b) a
+      | (a, b) when a = b -> a
+      | (a, b) -> SIZE_rt_max (a, b)
+;;
+
+(* FIXME: audit this carefuly; I am not terribly certain of the
+ * algebraic simplification going on here. Sadly, without it
+ * the diagnostic output from translation becomes completely
+ * illegible.
+ *)
+
+let align_sz (a:size) (b:size) : size =
+  let rec alignment_of s =
+    match s with
+        SIZE_rt_align (SIZE_fixed n, s) ->
+          let inner_alignment = alignment_of s in
+            if (Int64.rem n inner_alignment) = 0L
+            then inner_alignment
+            else n
+      | SIZE_rt_add (SIZE_fixed n, s)
+      | SIZE_rt_add (s, SIZE_fixed n) ->
+          let inner_alignment = alignment_of s in
+            if (Int64.rem n inner_alignment) = 0L
+            then inner_alignment
+            else 1L (* This could be lcd(...) or such. *)
+      | SIZE_rt_max (a, SIZE_fixed 1L) -> alignment_of a
+      | SIZE_rt_max (SIZE_fixed 1L, b) -> alignment_of b
+      | _ -> 1L
+  in
+    match (a, b) with
+        (SIZE_fixed a, SIZE_fixed b) -> SIZE_fixed (i64_align a b)
+      | (SIZE_fixed x, _) when i64_lt x 1L -> bug () "alignment less than 1"
+      | (SIZE_fixed 1L, b) -> b (* everything is 1-aligned. *)
+      | (_, SIZE_fixed 0L) -> b (* 0 is everything-aligned. *)
+      | (SIZE_fixed a, b) ->
+          let inner_alignment = alignment_of b in
+          if (Int64.rem a inner_alignment) = 0L
+          then b
+          else SIZE_rt_align (SIZE_fixed a, b)
+      | (SIZE_rt_max (a, SIZE_fixed 1L), b) -> SIZE_rt_align (a, b)
+      | (SIZE_rt_max (SIZE_fixed 1L, a), b) -> SIZE_rt_align (a, b)
+      | (a, b) -> SIZE_rt_align (a, b)
+;;
+
+let force_sz (a:size) : int64 =
+  match a with
+      SIZE_fixed i -> i
+    | _ -> bug () "force_sz: forced non-fixed size expression %s"
+        (string_of_size a)
+;;
+
+(*
+ * Local Variables:
+ * fill-column: 78;
+ * indent-tabs-mode: nil
+ * buffer-file-coding-system: utf-8-unix
+ * compile-command: "make -k -C ../.. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+ * End:
+ *)