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cmm_helpers.ml
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(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. *)
(* *)
(* All rights reserved. This file is distributed under the terms of *)
(* the GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
[@@@ocaml.warning "+a-4-9-40-41-42-44-45"]
module V = Backend_var
module VP = Backend_var.With_provenance
open Cmm
open Arch
(* Local binding of complex expressions *)
let bind name arg fn =
match arg with
Cvar _ | Cconst_int _ | Cconst_natint _ | Cconst_symbol _ -> fn arg
| _ -> let id = V.create_local name in Clet(VP.create id, arg, fn (Cvar id))
let bind_load name arg fn =
match arg with
| Cop(Cload _, [Cvar _], _) -> fn arg
| _ -> bind name arg fn
let bind_nonvar name arg fn =
match arg with
Cconst_int _ | Cconst_natint _ | Cconst_symbol _ -> fn arg
| _ -> let id = V.create_local name in Clet(VP.create id, arg, fn (Cvar id))
let caml_black = Nativeint.shift_left (Nativeint.of_int 3) 8
(* cf. runtime/caml/gc.h *)
(* Loads *)
let mk_load_immut memory_chunk =
Cload {memory_chunk; mutability=Immutable; is_atomic=false}
let mk_load_mut memory_chunk =
Cload {memory_chunk; mutability=Mutable; is_atomic=false}
let mk_load_atomic memory_chunk =
Cload {memory_chunk; mutability=Mutable; is_atomic=true}
(* Block headers. Meaning of the tag field: see stdlib/obj.ml *)
let floatarray_tag dbg = Cconst_int (Obj.double_array_tag, dbg)
let block_header tag sz =
Nativeint.add (Nativeint.shift_left (Nativeint.of_int sz) 10)
(Nativeint.of_int tag)
(* Static data corresponding to "value"s must be marked black in case we are
in no-naked-pointers mode. See [caml_darken] and the code below that emits
structured constants and static module definitions. *)
let black_block_header tag sz = Nativeint.logor (block_header tag sz) caml_black
let white_closure_header sz = block_header Obj.closure_tag sz
let black_closure_header sz = black_block_header Obj.closure_tag sz
let infix_header ofs = block_header Obj.infix_tag ofs
let float_header = block_header Obj.double_tag (size_float / size_addr)
let floatarray_header len =
(* Zero-sized float arrays have tag zero for consistency with
[caml_alloc_float_array]. *)
assert (len >= 0);
if len = 0 then block_header 0 0
else block_header Obj.double_array_tag (len * size_float / size_addr)
let string_header len =
block_header Obj.string_tag ((len + size_addr) / size_addr)
let boxedint32_header = block_header Obj.custom_tag 2
let boxedint64_header = block_header Obj.custom_tag (1 + 8 / size_addr)
let boxedintnat_header = block_header Obj.custom_tag 2
let caml_nativeint_ops = "caml_nativeint_ops"
let caml_int32_ops = "caml_int32_ops"
let caml_int64_ops = "caml_int64_ops"
let pos_arity_in_closinfo = 8 * size_addr - 8
(* arity = the top 8 bits of the closinfo word *)
let closure_info ~arity ~startenv =
assert (-128 <= arity && arity <= 127);
assert (0 <= startenv && startenv < 1 lsl (pos_arity_in_closinfo - 1));
Nativeint.(add (shift_left (of_int arity) pos_arity_in_closinfo)
(add (shift_left (of_int startenv) 1)
1n))
let alloc_float_header dbg = Cconst_natint (float_header, dbg)
let alloc_floatarray_header len dbg = Cconst_natint (floatarray_header len, dbg)
let alloc_closure_header sz dbg = Cconst_natint (white_closure_header sz, dbg)
let alloc_infix_header ofs dbg = Cconst_natint (infix_header ofs, dbg)
let alloc_closure_info ~arity ~startenv dbg =
Cconst_natint (closure_info ~arity ~startenv, dbg)
let alloc_boxedint32_header dbg = Cconst_natint (boxedint32_header, dbg)
let alloc_boxedint64_header dbg = Cconst_natint (boxedint64_header, dbg)
let alloc_boxedintnat_header dbg = Cconst_natint (boxedintnat_header, dbg)
(* Integers *)
let max_repr_int = max_int asr 1
let min_repr_int = min_int asr 1
let int_const dbg n =
if n <= max_repr_int && n >= min_repr_int
then Cconst_int((n lsl 1) + 1, dbg)
else Cconst_natint
(Nativeint.add (Nativeint.shift_left (Nativeint.of_int n) 1) 1n, dbg)
let natint_const_untagged dbg n =
if n > Nativeint.of_int max_int
|| n < Nativeint.of_int min_int
then Cconst_natint (n,dbg)
else Cconst_int (Nativeint.to_int n, dbg)
let cint_const n =
Cint(Nativeint.add (Nativeint.shift_left (Nativeint.of_int n) 1) 1n)
let targetint_const n =
Targetint.add (Targetint.shift_left (Targetint.of_int n) 1)
Targetint.one
let add_no_overflow n x c dbg =
let d = n + x in
if d = 0 then c else Cop(Caddi, [c; Cconst_int (d, dbg)], dbg)
let rec add_const c n dbg =
if n = 0 then c
else match c with
| Cconst_int (x, _) when Misc.no_overflow_add x n -> Cconst_int (x + n, dbg)
| Cop(Caddi, [Cconst_int (x, _); c], _)
when Misc.no_overflow_add n x ->
add_no_overflow n x c dbg
| Cop(Caddi, [c; Cconst_int (x, _)], _)
when Misc.no_overflow_add n x ->
add_no_overflow n x c dbg
| Cop(Csubi, [Cconst_int (x, _); c], _) when Misc.no_overflow_add n x ->
Cop(Csubi, [Cconst_int (n + x, dbg); c], dbg)
| Cop(Csubi, [c; Cconst_int (x, _)], _) when Misc.no_overflow_sub n x ->
add_const c (n - x) dbg
| c -> Cop(Caddi, [c; Cconst_int (n, dbg)], dbg)
let incr_int c dbg = add_const c 1 dbg
let decr_int c dbg = add_const c (-1) dbg
let rec add_int c1 c2 dbg =
match (c1, c2) with
| (Cconst_int (n, _), c) | (c, Cconst_int (n, _)) ->
add_const c n dbg
| (Cop(Caddi, [c1; Cconst_int (n1, _)], _), c2) ->
add_const (add_int c1 c2 dbg) n1 dbg
| (c1, Cop(Caddi, [c2; Cconst_int (n2, _)], _)) ->
add_const (add_int c1 c2 dbg) n2 dbg
| (_, _) ->
Cop(Caddi, [c1; c2], dbg)
let rec sub_int c1 c2 dbg =
match (c1, c2) with
| (c1, Cconst_int (n2, _)) when n2 <> min_int ->
add_const c1 (-n2) dbg
| (c1, Cop(Caddi, [c2; Cconst_int (n2, _)], _)) when n2 <> min_int ->
add_const (sub_int c1 c2 dbg) (-n2) dbg
| (Cop(Caddi, [c1; Cconst_int (n1, _)], _), c2) ->
add_const (sub_int c1 c2 dbg) n1 dbg
| (c1, c2) ->
Cop(Csubi, [c1; c2], dbg)
let rec lsl_int c1 c2 dbg =
match (c1, c2) with
| (Cop(Clsl, [c; Cconst_int (n1, _)], _), Cconst_int (n2, _))
when n1 > 0 && n2 > 0 && n1 + n2 < size_int * 8 ->
Cop(Clsl, [c; Cconst_int (n1 + n2, dbg)], dbg)
| (Cop(Caddi, [c1; Cconst_int (n1, _)], _), Cconst_int (n2, _))
when Misc.no_overflow_lsl n1 n2 ->
add_const (lsl_int c1 c2 dbg) (n1 lsl n2) dbg
| (_, _) ->
Cop(Clsl, [c1; c2], dbg)
let is_power2 n = n = 1 lsl Misc.log2 n
and mult_power2 c n dbg = lsl_int c (Cconst_int (Misc.log2 n, dbg)) dbg
let rec mul_int c1 c2 dbg =
match (c1, c2) with
| (c, Cconst_int (0, _)) | (Cconst_int (0, _), c) ->
Csequence (c, Cconst_int (0, dbg))
| (c, Cconst_int (1, _)) | (Cconst_int (1, _), c) ->
c
| (c, Cconst_int(-1, _)) | (Cconst_int(-1, _), c) ->
sub_int (Cconst_int (0, dbg)) c dbg
| (c, Cconst_int (n, _)) when is_power2 n -> mult_power2 c n dbg
| (Cconst_int (n, _), c) when is_power2 n -> mult_power2 c n dbg
| (Cop(Caddi, [c; Cconst_int (n, _)], _), Cconst_int (k, _)) |
(Cconst_int (k, _), Cop(Caddi, [c; Cconst_int (n, _)], _))
when Misc.no_overflow_mul n k ->
add_const (mul_int c (Cconst_int (k, dbg)) dbg) (n * k) dbg
| (c1, c2) ->
Cop(Cmuli, [c1; c2], dbg)
let ignore_low_bit_int = function
Cop(Caddi,
[(Cop(Clsl, [_; Cconst_int (n, _)], _) as c); Cconst_int (1, _)], _)
when n > 0
-> c
| Cop(Cor, [c; Cconst_int (1, _)], _) -> c
| c -> c
(* removes the 1-bit sign-extension left by untag_int (tag_int c) *)
let ignore_high_bit_int = function
Cop(Casr,
[Cop(Clsl, [c; Cconst_int (1, _)], _); Cconst_int (1, _)], _) -> c
| c -> c
let lsr_int c1 c2 dbg =
match c2 with
Cconst_int (0, _) ->
c1
| Cconst_int (n, _) when n > 0 ->
Cop(Clsr, [ignore_low_bit_int c1; c2], dbg)
| _ ->
Cop(Clsr, [c1; c2], dbg)
let asr_int c1 c2 dbg =
match c2 with
Cconst_int (0, _) ->
c1
| Cconst_int (n, _) when n > 0 ->
Cop(Casr, [ignore_low_bit_int c1; c2], dbg)
| _ ->
Cop(Casr, [c1; c2], dbg)
let tag_int i dbg =
match i with
Cconst_int (n, _) ->
int_const dbg n
| Cop(Casr, [c; Cconst_int (n, _)], _) when n > 0 ->
Cop(Cor,
[asr_int c (Cconst_int (n - 1, dbg)) dbg; Cconst_int (1, dbg)],
dbg)
| c ->
incr_int (lsl_int c (Cconst_int (1, dbg)) dbg) dbg
let untag_int i dbg =
match i with
Cconst_int (n, _) -> Cconst_int(n asr 1, dbg)
| Cop(Cor, [Cop(Casr, [c; Cconst_int (n, _)], _); Cconst_int (1, _)], _)
when n > 0 && n < size_int * 8 ->
Cop(Casr, [c; Cconst_int (n+1, dbg)], dbg)
| Cop(Cor, [Cop(Clsr, [c; Cconst_int (n, _)], _); Cconst_int (1, _)], _)
when n > 0 && n < size_int * 8 ->
Cop(Clsr, [c; Cconst_int (n+1, dbg)], dbg)
| c -> asr_int c (Cconst_int (1, dbg)) dbg
let mk_if_then_else dbg cond ifso_dbg ifso ifnot_dbg ifnot =
match cond with
| Cconst_int (0, _) -> ifnot
| Cconst_int (1, _) -> ifso
| _ ->
Cifthenelse(cond, ifso_dbg, ifso, ifnot_dbg, ifnot, dbg)
let mk_not dbg cmm =
match cmm with
| Cop(Caddi,
[Cop(Clsl, [c; Cconst_int (1, _)], _); Cconst_int (1, _)], dbg') ->
begin
match c with
| Cop(Ccmpi cmp, [c1; c2], dbg'') ->
tag_int
(Cop(Ccmpi (negate_integer_comparison cmp), [c1; c2], dbg'')) dbg'
| Cop(Ccmpa cmp, [c1; c2], dbg'') ->
tag_int
(Cop(Ccmpa (negate_integer_comparison cmp), [c1; c2], dbg'')) dbg'
| Cop(Ccmpf cmp, [c1; c2], dbg'') ->
tag_int
(Cop(Ccmpf (negate_float_comparison cmp), [c1; c2], dbg'')) dbg'
| _ ->
(* 0 -> 3, 1 -> 1 *)
Cop(Csubi,
[Cconst_int (3, dbg); Cop(Clsl, [c; Cconst_int (1, dbg)], dbg)],
dbg)
end
| Cconst_int (3, _) -> Cconst_int (1, dbg)
| Cconst_int (1, _) -> Cconst_int (3, dbg)
| c ->
(* 1 -> 3, 3 -> 1 *)
Cop(Csubi, [Cconst_int (4, dbg); c], dbg)
let mk_compare_ints dbg a1 a2 =
match (a1,a2) with
| Cconst_int (c1, _), Cconst_int (c2, _) ->
int_const dbg (Int.compare c1 c2)
| Cconst_natint (c1, _), Cconst_natint (c2, _) ->
int_const dbg (Nativeint.compare c1 c2)
| Cconst_int (c1, _), Cconst_natint (c2, _) ->
int_const dbg Nativeint.(compare (of_int c1) c2)
| Cconst_natint (c1, _), Cconst_int (c2, _) ->
int_const dbg Nativeint.(compare c1 (of_int c2))
| a1, a2 -> begin
bind "int_cmp" a2 (fun a2 ->
bind "int_cmp" a1 (fun a1 ->
let op1 = Cop(Ccmpi(Cgt), [a1; a2], dbg) in
let op2 = Cop(Ccmpi(Clt), [a1; a2], dbg) in
tag_int(sub_int op1 op2 dbg) dbg))
end
let mk_compare_floats dbg a1 a2 =
bind "float_cmp" a2 (fun a2 ->
bind "float_cmp" a1 (fun a1 ->
let op1 = Cop(Ccmpf(CFgt), [a1; a2], dbg) in
let op2 = Cop(Ccmpf(CFlt), [a1; a2], dbg) in
let op3 = Cop(Ccmpf(CFeq), [a1; a1], dbg) in
let op4 = Cop(Ccmpf(CFeq), [a2; a2], dbg) in
(* If both operands a1 and a2 are not NaN, then op3 = op4 = 1,
and the result is op1 - op2.
If at least one of the operands is NaN,
then op1 = op2 = 0, and the result is op3 - op4,
which orders NaN before other values.
To detect if the operand is NaN, we use the property:
for all x, NaN is not equal to x, even if x is NaN.
Therefore, op3 is 0 if and only if a1 is NaN,
and op4 is 0 if and only if a2 is NaN.
See also caml_float_compare_unboxed in runtime/floats.c *)
tag_int (add_int (sub_int op1 op2 dbg) (sub_int op3 op4 dbg) dbg) dbg))
let create_loop body dbg =
let cont = Lambda.next_raise_count () in
let call_cont = Cexit (cont, []) in
let body = Csequence (body, call_cont) in
Ccatch (Recursive, [cont, [], body, dbg], call_cont)
(* Turning integer divisions into multiply-high then shift.
The [division_parameters] function is used in module Emit for
those target platforms that support this optimization. *)
(* Unsigned comparison between native integers. *)
let ucompare x y = Nativeint.(compare (add x min_int) (add y min_int))
(* Unsigned division and modulus at type nativeint.
Algorithm: Hacker's Delight section 9.3 *)
let udivmod n d = Nativeint.(
if d < 0n then
if ucompare n d < 0 then (0n, n) else (1n, sub n d)
else begin
let q = shift_left (div (shift_right_logical n 1) d) 1 in
let r = sub n (mul q d) in
if ucompare r d >= 0 then (succ q, sub r d) else (q, r)
end)
(* Compute division parameters.
Algorithm: Hacker's Delight chapter 10, fig 10-1. *)
let divimm_parameters d = Nativeint.(
assert (d > 0n);
let twopsm1 = min_int in (* 2^31 for 32-bit archs, 2^63 for 64-bit archs *)
let nc = sub (pred twopsm1) (snd (udivmod twopsm1 d)) in
let rec loop p (q1, r1) (q2, r2) =
let p = p + 1 in
let q1 = shift_left q1 1 and r1 = shift_left r1 1 in
let (q1, r1) =
if ucompare r1 nc >= 0 then (succ q1, sub r1 nc) else (q1, r1) in
let q2 = shift_left q2 1 and r2 = shift_left r2 1 in
let (q2, r2) =
if ucompare r2 d >= 0 then (succ q2, sub r2 d) else (q2, r2) in
let delta = sub d r2 in
if ucompare q1 delta < 0 || (q1 = delta && r1 = 0n)
then loop p (q1, r1) (q2, r2)
else (succ q2, p - size)
in loop (size - 1) (udivmod twopsm1 nc) (udivmod twopsm1 d))
(* The result [(m, p)] of [divimm_parameters d] satisfies the following
inequality:
2^(wordsize + p) < m * d <= 2^(wordsize + p) + 2^(p + 1) (i)
from which it follows that
floor(n / d) = floor(n * m / 2^(wordsize+p))
if 0 <= n < 2^(wordsize-1)
ceil(n / d) = floor(n * m / 2^(wordsize+p)) + 1
if -2^(wordsize-1) <= n < 0
The correctness condition (i) above can be checked by the code below.
It was exhaustively tested for values of d from 2 to 10^9 in the
wordsize = 64 case.
let add2 (xh, xl) (yh, yl) =
let zl = add xl yl and zh = add xh yh in
((if ucompare zl xl < 0 then succ zh else zh), zl)
let shl2 (xh, xl) n =
assert (0 < n && n < size + size);
if n < size
then (logor (shift_left xh n) (shift_right_logical xl (size - n)),
shift_left xl n)
else (shift_left xl (n - size), 0n)
let mul2 x y =
let halfsize = size / 2 in
let halfmask = pred (shift_left 1n halfsize) in
let xl = logand x halfmask and xh = shift_right_logical x halfsize in
let yl = logand y halfmask and yh = shift_right_logical y halfsize in
add2 (mul xh yh, 0n)
(add2 (shl2 (0n, mul xl yh) halfsize)
(add2 (shl2 (0n, mul xh yl) halfsize)
(0n, mul xl yl)))
let ucompare2 (xh, xl) (yh, yl) =
let c = ucompare xh yh in if c = 0 then ucompare xl yl else c
let validate d m p =
let md = mul2 m d in
let one2 = (0n, 1n) in
let twoszp = shl2 one2 (size + p) in
let twop1 = shl2 one2 (p + 1) in
ucompare2 twoszp md < 0 && ucompare2 md (add2 twoszp twop1) <= 0
*)
let raise_symbol dbg symb =
Cop(Craise Lambda.Raise_regular, [Cconst_symbol (symb, dbg)], dbg)
let rec div_int c1 c2 is_safe dbg =
match (c1, c2) with
(c1, Cconst_int (0, _)) ->
Csequence(c1, raise_symbol dbg "caml_exn_Division_by_zero")
| (c1, Cconst_int (1, _)) ->
c1
| (Cconst_int (n1, _), Cconst_int (n2, _)) ->
Cconst_int (n1 / n2, dbg)
| (c1, Cconst_int (n, _)) when n <> min_int ->
let l = Misc.log2 n in
if n = 1 lsl l then
(* Algorithm:
t = shift-right-signed(c1, l - 1)
t = shift-right(t, W - l)
t = c1 + t
res = shift-right-signed(c1 + t, l)
*)
Cop(Casr, [bind "dividend" c1 (fun c1 ->
let t = asr_int c1 (Cconst_int (l - 1, dbg)) dbg in
let t =
lsr_int t (Cconst_int (Nativeint.size - l, dbg)) dbg
in
add_int c1 t dbg);
Cconst_int (l, dbg)], dbg)
else if n < 0 then
sub_int (Cconst_int (0, dbg))
(div_int c1 (Cconst_int (-n, dbg)) is_safe dbg)
dbg
else begin
let (m, p) = divimm_parameters (Nativeint.of_int n) in
(* Algorithm:
t = multiply-high-signed(c1, m)
if m < 0, t = t + c1
if p > 0, t = shift-right-signed(t, p)
res = t + sign-bit(c1)
*)
bind "dividend" c1 (fun c1 ->
let t = Cop(Cmulhi, [c1; natint_const_untagged dbg m], dbg) in
let t = if m < 0n then Cop(Caddi, [t; c1], dbg) else t in
let t =
if p > 0 then Cop(Casr, [t; Cconst_int (p, dbg)], dbg) else t
in
add_int t (lsr_int c1 (Cconst_int (Nativeint.size - 1, dbg)) dbg) dbg)
end
| (c1, c2) when !Clflags.unsafe || is_safe = Lambda.Unsafe ->
Cop(Cdivi, [c1; c2], dbg)
| (c1, c2) ->
bind "divisor" c2 (fun c2 ->
bind "dividend" c1 (fun c1 ->
Cifthenelse(c2,
dbg,
Cop(Cdivi, [c1; c2], dbg),
dbg,
raise_symbol dbg "caml_exn_Division_by_zero",
dbg)))
let mod_int c1 c2 is_safe dbg =
match (c1, c2) with
(c1, Cconst_int (0, _)) ->
Csequence(c1, raise_symbol dbg "caml_exn_Division_by_zero")
| (c1, Cconst_int ((1 | (-1)), _)) ->
Csequence(c1, Cconst_int (0, dbg))
| (Cconst_int (n1, _), Cconst_int (n2, _)) ->
Cconst_int (n1 mod n2, dbg)
| (c1, (Cconst_int (n, _) as c2)) when n <> min_int ->
let l = Misc.log2 n in
if n = 1 lsl l then
(* Algorithm:
t = shift-right-signed(c1, l - 1)
t = shift-right(t, W - l)
t = c1 + t
t = bit-and(t, -n)
res = c1 - t
*)
bind "dividend" c1 (fun c1 ->
let t = asr_int c1 (Cconst_int (l - 1, dbg)) dbg in
let t = lsr_int t (Cconst_int (Nativeint.size - l, dbg)) dbg in
let t = add_int c1 t dbg in
let t = Cop(Cand, [t; Cconst_int (-n, dbg)], dbg) in
sub_int c1 t dbg)
else
bind "dividend" c1 (fun c1 ->
sub_int c1 (mul_int (div_int c1 c2 is_safe dbg) c2 dbg) dbg)
| (c1, c2) when !Clflags.unsafe || is_safe = Lambda.Unsafe ->
(* Flambda already generates that test *)
Cop(Cmodi, [c1; c2], dbg)
| (c1, c2) ->
bind "divisor" c2 (fun c2 ->
bind "dividend" c1 (fun c1 ->
Cifthenelse(c2,
dbg,
Cop(Cmodi, [c1; c2], dbg),
dbg,
raise_symbol dbg "caml_exn_Division_by_zero",
dbg)))
(* Division or modulo on boxed integers. The overflow case min_int / -1
can occur, in which case we force x / -1 = -x and x mod -1 = 0. (PR#5513). *)
let is_different_from x = function
Cconst_int (n, _) -> n <> x
| Cconst_natint (n, _) -> n <> Nativeint.of_int x
| _ -> false
let safe_divmod_bi mkop is_safe mkm1 c1 c2 bi dbg =
bind "divisor" c2 (fun c2 ->
bind "dividend" c1 (fun c1 ->
let c = mkop c1 c2 is_safe dbg in
if Arch.division_crashes_on_overflow
&& bi <> Primitive.Pint32
&& not (is_different_from (-1) c2)
then
Cifthenelse(Cop(Ccmpi Cne, [c2; Cconst_int (-1, dbg)], dbg),
dbg, c,
dbg, mkm1 c1 dbg,
dbg)
else
c))
let safe_div_bi is_safe =
safe_divmod_bi div_int is_safe
(fun c1 dbg -> Cop(Csubi, [Cconst_int (0, dbg); c1], dbg))
let safe_mod_bi is_safe =
safe_divmod_bi mod_int is_safe (fun _ dbg -> Cconst_int (0, dbg))
(* Bool *)
let test_bool dbg cmm =
match cmm with
| Cop(Caddi, [Cop(Clsl, [c; Cconst_int (1, _)], _); Cconst_int (1, _)], _) ->
c
| Cconst_int (n, dbg) ->
if n = 1 then
Cconst_int (0, dbg)
else
Cconst_int (1, dbg)
| c -> Cop(Ccmpi Cne, [c; Cconst_int (1, dbg)], dbg)
(* Float *)
let box_float dbg c = Cop(Calloc, [alloc_float_header dbg; c], dbg)
let unbox_float dbg =
map_tail
(function
| Cop(Calloc, [Cconst_natint (hdr, _); c], _)
when Nativeint.equal hdr float_header ->
c
| Cconst_symbol (s, _dbg) as cmm ->
begin match Cmmgen_state.structured_constant_of_sym s with
| Some (Uconst_float x) ->
Cconst_float (x, dbg) (* or keep _dbg? *)
| _ ->
Cop(mk_load_immut Double, [cmm], dbg)
end
| cmm -> Cop(mk_load_immut Double, [cmm], dbg)
)
(* Conversions for 16-bit floats *)
let float_of_float16 dbg c =
Cop(Cextcall("caml_double_of_float16", typ_float, [XInt], false), [c], dbg)
let float16_of_float dbg c =
Cop(Cextcall("caml_float16_of_double", typ_int, [XFloat], false), [c], dbg)
(* Complex *)
let box_complex dbg c_re c_im =
Cop(Calloc, [alloc_floatarray_header 2 dbg; c_re; c_im], dbg)
let complex_re c dbg =
Cop(mk_load_immut Double, [c], dbg)
let complex_im c dbg =
Cop(mk_load_immut Double,
[Cop(Cadda, [c; Cconst_int (size_float, dbg)], dbg)], dbg)
(* Unit *)
let return_unit dbg c = Csequence(c, Cconst_int (1, dbg))
let rec remove_unit = function
Cconst_int (1, _) -> Ctuple []
| Csequence(c, Cconst_int (1, _)) -> c
| Csequence(c1, c2) ->
Csequence(c1, remove_unit c2)
| Cifthenelse(cond, ifso_dbg, ifso, ifnot_dbg, ifnot, dbg) ->
Cifthenelse(cond,
ifso_dbg, remove_unit ifso,
ifnot_dbg,
remove_unit ifnot, dbg)
| Cswitch(sel, index, cases, dbg) ->
Cswitch(sel, index,
Array.map (fun (case, dbg) -> remove_unit case, dbg) cases,
dbg)
| Ccatch(rec_flag, handlers, body) ->
let map_h (n, ids, handler, dbg) = (n, ids, remove_unit handler, dbg) in
Ccatch(rec_flag, List.map map_h handlers, remove_unit body)
| Ctrywith(body, exn, handler, dbg) ->
Ctrywith(remove_unit body, exn, remove_unit handler, dbg)
| Clet(id, c1, c2) ->
Clet(id, c1, remove_unit c2)
| Cop(Capply _mty, args, dbg) ->
Cop(Capply typ_void, args, dbg)
| Cop(Cextcall(proc, _ty_res, ty_args, alloc), args, dbg) ->
Cop(Cextcall(proc, typ_void, ty_args, alloc), args, dbg)
| Cexit (_,_) as c -> c
| Ctuple [] as c -> c
| c -> Csequence(c, Ctuple [])
let field_address ptr n dbg =
if n = 0
then ptr
else Cop(Cadda, [ptr; Cconst_int(n * size_addr, dbg)], dbg)
let get_field_gen mutability ptr n dbg =
Cop(Cload {memory_chunk=Word_val; mutability; is_atomic=false},
[field_address ptr n dbg], dbg)
let get_field_codepointer mutability ptr n dbg =
Cop(Cload {memory_chunk=Word_int; mutability; is_atomic=false},
[field_address ptr n dbg], dbg)
let set_field ptr n newval init dbg =
Cop(Cstore (Word_val, init), [field_address ptr n dbg; newval], dbg)
let get_header ptr dbg =
(* Headers can be mutated when forcing a lazy value. However, for all
purposes that the mutability tag currently serves in the compiler, header
loads can be marked as [Immutable], since the runtime should ensure that
there is no data race on headers. This saves performance with
ThreadSanitizer instrumentation by avoiding to instrument header loads. *)
Cop(
mk_load_immut Word_int,
[Cop(Cadda, [ptr; Cconst_int(-size_int, dbg)], dbg)], dbg)
let get_header_masked ptr dbg =
if Config.reserved_header_bits > 0 then
let header_mask = (1 lsl (64 - Config.reserved_header_bits)) - 1
in Cop(Cand, [get_header ptr dbg; Cconst_int (header_mask, dbg)], dbg)
else
get_header ptr dbg
let tag_offset =
if big_endian then -1 else -size_int
let get_tag ptr dbg =
if Proc.word_addressed then (* If byte loads are slow *)
Cop(Cand, [get_header ptr dbg; Cconst_int (255, dbg)], dbg)
else (* If byte loads are efficient *)
(* Same comment as [get_header] above *)
Cop(
mk_load_immut Byte_unsigned,
[Cop(Cadda, [ptr; Cconst_int(tag_offset, dbg)], dbg)], dbg)
let get_size ptr dbg =
Cop(Clsr, [get_header_masked ptr dbg; Cconst_int (10, dbg)], dbg)
(* Array indexing *)
let log2_size_addr = Misc.log2 size_addr
let log2_size_float = Misc.log2 size_float
let wordsize_shift = 9
let numfloat_shift = 9 + log2_size_float - log2_size_addr
let is_addr_array_hdr hdr dbg =
Cop(Ccmpi Cne,
[Cop(Cand, [hdr; Cconst_int (255, dbg)], dbg); floatarray_tag dbg],
dbg)
let is_addr_array_ptr ptr dbg =
Cop(Ccmpi Cne, [get_tag ptr dbg; floatarray_tag dbg], dbg)
let addr_array_length_shifted hdr dbg =
Cop(Clsr, [hdr; Cconst_int (wordsize_shift, dbg)], dbg)
let float_array_length_shifted hdr dbg =
Cop(Clsr, [hdr; Cconst_int (numfloat_shift, dbg)], dbg)
let lsl_const c n dbg =
if n = 0 then c
else Cop(Clsl, [c; Cconst_int (n, dbg)], dbg)
(* Produces a pointer to the element of the array [ptr] on the position [ofs]
with the given element [log2size] log2 element size. [ofs] is given as a
tagged int expression.
The optional ?typ argument is the C-- type of the result.
By default, it is Addr, meaning we are constructing a derived pointer
into the heap. If we know the pointer is outside the heap
(this is the case for bigarray indexing), we give type Int instead. *)
let array_indexing ?typ log2size ptr ofs dbg =
let add =
match typ with
| None | Some Addr -> Cadda
| Some Int -> Caddi
| _ -> assert false in
match ofs with
| Cconst_int (n, _) ->
let i = n asr 1 in
if i = 0 then ptr
else Cop(add, [ptr; Cconst_int(i lsl log2size, dbg)], dbg)
| Cop(Caddi,
[Cop(Clsl, [c; Cconst_int (1, _)], _); Cconst_int (1, _)], dbg') ->
Cop(add, [ptr; lsl_const c log2size dbg], dbg')
| Cop(Caddi, [c; Cconst_int (n, _)], dbg') when log2size = 0 ->
Cop(add,
[Cop(add, [ptr; untag_int c dbg], dbg); Cconst_int (n asr 1, dbg)],
dbg')
| Cop(Caddi, [c; Cconst_int (n, _)], _) ->
Cop(add, [Cop(add, [ptr; lsl_const c (log2size - 1) dbg], dbg);
Cconst_int((n-1) lsl (log2size - 1), dbg)], dbg)
| _ when log2size = 0 ->
Cop(add, [ptr; untag_int ofs dbg], dbg)
| _ ->
Cop(add, [Cop(add, [ptr; lsl_const ofs (log2size - 1) dbg], dbg);
Cconst_int((-1) lsl (log2size - 1), dbg)], dbg)
let addr_array_ref arr ofs dbg =
Cop(mk_load_mut Word_val,
[array_indexing log2_size_addr arr ofs dbg], dbg)
let int_array_ref arr ofs dbg =
Cop(mk_load_mut Word_int,
[array_indexing log2_size_addr arr ofs dbg], dbg)
let unboxed_float_array_ref arr ofs dbg =
Cop(mk_load_mut Double,
[array_indexing log2_size_float arr ofs dbg], dbg)
let float_array_ref arr ofs dbg =
box_float dbg (unboxed_float_array_ref arr ofs dbg)
let addr_array_set arr ofs newval dbg =
Cop(Cextcall("caml_modify", typ_void, [], false),
[array_indexing log2_size_addr arr ofs dbg; newval], dbg)
let addr_array_initialize arr ofs newval dbg =
Cop(Cextcall("caml_initialize", typ_void, [], false),
[array_indexing log2_size_addr arr ofs dbg; newval], dbg)
let int_array_set arr ofs newval dbg =
Cop(Cstore (Word_int, Lambda.Assignment),
[array_indexing log2_size_addr arr ofs dbg; newval], dbg)
let float_array_set arr ofs newval dbg =
Cop(Cstore (Double, Lambda.Assignment),
[array_indexing log2_size_float arr ofs dbg; newval], dbg)
(* String length *)
(* Length of string block *)
let string_length exp dbg =
bind "str" exp (fun str ->
let tmp_var = V.create_local "tmp" in
Clet(VP.create tmp_var,
Cop(Csubi,
[Cop(Clsl,
[get_size str dbg;
Cconst_int (log2_size_addr, dbg)],
dbg);
Cconst_int (1, dbg)],
dbg),
Cop(Csubi,
[Cvar tmp_var;
Cop(mk_load_mut Byte_unsigned,
[Cop(Cadda, [str; Cvar tmp_var], dbg)], dbg)], dbg)))
let bigstring_length ba dbg =
Cop(mk_load_mut Word_int, [field_address ba 5 dbg], dbg)
(* Message sending *)
let lookup_tag obj tag dbg =
bind "tag" tag (fun tag ->
Cop(Cextcall("caml_get_public_method", typ_val, [], false),
[obj; tag],
dbg))
let lookup_label obj lab dbg =
bind "lab" lab (fun lab ->
let table = Cop (mk_load_mut Word_val, [obj], dbg) in
addr_array_ref table lab dbg)
let call_cached_method obj tag cache pos args dbg =
let arity = List.length args in
let cache = array_indexing log2_size_addr cache pos dbg in
Compilenv.need_send_fun arity;
Cop(Capply typ_val,
Cconst_symbol("caml_send" ^ Int.to_string arity, dbg) ::
obj :: tag :: cache :: args,
dbg)
(* Allocation *)
let make_alloc_generic set_fn dbg tag wordsize args =
if wordsize <= Config.max_young_wosize then
Cop(Calloc, Cconst_natint(block_header tag wordsize, dbg) :: args, dbg)
else begin
let id = V.create_local "*alloc*" in
let rec fill_fields idx = function
[] -> Cvar id
| e1::el -> Csequence(set_fn (Cvar id) (Cconst_int (idx, dbg)) e1 dbg,
fill_fields (idx + 2) el) in
Clet(VP.create id,
Cop(Cextcall("caml_alloc_shr_check_gc", typ_val, [], true),
[Cconst_int (wordsize, dbg); Cconst_int (tag, dbg)], dbg),
fill_fields 1 args)
end
let make_alloc dbg tag args =
let addr_array_init arr ofs newval dbg =
Cop(Cextcall("caml_initialize", typ_void, [], false),
[array_indexing log2_size_addr arr ofs dbg; newval], dbg)
in
make_alloc_generic addr_array_init dbg tag (List.length args) args
let make_float_alloc dbg tag args =
make_alloc_generic float_array_set dbg tag
(List.length args * size_float / size_addr) args
(* Bounds checking *)
let make_checkbound dbg = function
| [Cop(Clsr, [a1; Cconst_int (n, _)], _); Cconst_int (m, _)]
when (m lsl n) > n ->
Cop(Ccheckbound, [a1; Cconst_int(m lsl n + 1 lsl n - 1, dbg)], dbg)
| args ->
Cop(Ccheckbound, args, dbg)
(* Record application and currying functions *)
let apply_function_sym n =
Compilenv.need_apply_fun n; "caml_apply" ^ Int.to_string n
let curry_function_sym n =
Compilenv.need_curry_fun n;
if n >= 0
then "caml_curry" ^ Int.to_string n
else "caml_tuplify" ^ Int.to_string (-n)
(* Big arrays *)
let bigarray_elt_size : Lambda.bigarray_kind -> int = function
Pbigarray_unknown -> assert false
| Pbigarray_float16 -> 2
| Pbigarray_float32 -> 4
| Pbigarray_float64 -> 8
| Pbigarray_sint8 -> 1
| Pbigarray_uint8 -> 1
| Pbigarray_sint16 -> 2
| Pbigarray_uint16 -> 2
| Pbigarray_int32 -> 4
| Pbigarray_int64 -> 8
| Pbigarray_caml_int -> size_int
| Pbigarray_native_int -> size_int
| Pbigarray_complex32 -> 8
| Pbigarray_complex64 -> 16
(* Produces a pointer to the element of the bigarray [b] on the position
[args]. [args] is given as a list of tagged int expressions, one per array
dimension. *)
let bigarray_indexing unsafe elt_kind layout b args dbg =
let check_ba_bound bound idx v =
Csequence(make_checkbound dbg [bound;idx], v) in
(* Validates the given multidimensional offset against the array bounds and
transforms it into a one dimensional offset. The offsets are expressions
evaluating to tagged int. *)
let rec ba_indexing dim_ofs delta_ofs = function
[] -> assert false
| [arg] ->
if unsafe then arg
else
bind "idx" arg (fun idx ->
(* Load the untagged int bound for the given dimension *)
let bound =
Cop(mk_load_mut Word_int,
[field_address b dim_ofs dbg], dbg)
in
let idxn = untag_int idx dbg in
check_ba_bound bound idxn idx)
| arg1 :: argl ->
(* The remainder of the list is transformed into a one dimensional offset
*)
let rem = ba_indexing (dim_ofs + delta_ofs) delta_ofs argl in
(* Load the untagged int bound for the given dimension *)
let bound =
Cop(mk_load_mut Word_int,
[field_address b dim_ofs dbg], dbg)
in
if unsafe then add_int (mul_int (decr_int rem dbg) bound dbg) arg1 dbg
else
bind "idx" arg1 (fun idx ->
bind "bound" bound (fun bound ->
let idxn = untag_int idx dbg in
(* [offset = rem * (tag_int bound) + idx] *)
let offset =
add_int (mul_int (decr_int rem dbg) bound dbg) idx dbg
in
check_ba_bound bound idxn offset)) in
(* The offset as an expression evaluating to int *)
let offset =
match (layout : Lambda.bigarray_layout) with
Pbigarray_unknown_layout ->
assert false
| Pbigarray_c_layout ->
ba_indexing (4 + List.length args) (-1) (List.rev args)
| Pbigarray_fortran_layout ->
ba_indexing 5 1
(List.map (fun idx -> sub_int idx (Cconst_int (2, dbg)) dbg) args)
and elt_size =
bigarray_elt_size elt_kind in
(* [array_indexing] can simplify the given expressions *)
array_indexing ~typ:Addr (Misc.log2 elt_size)
(Cop(mk_load_mut Word_int,
[field_address b 1 dbg], dbg)) offset dbg
let bigarray_word_kind : Lambda.bigarray_kind -> memory_chunk = function
Pbigarray_unknown -> assert false
| Pbigarray_float16 -> Sixteen_unsigned
| Pbigarray_float32 -> Single
| Pbigarray_float64 -> Double
| Pbigarray_sint8 -> Byte_signed
| Pbigarray_uint8 -> Byte_unsigned
| Pbigarray_sint16 -> Sixteen_signed
| Pbigarray_uint16 -> Sixteen_unsigned
| Pbigarray_int32 -> Thirtytwo_signed
| Pbigarray_int64 -> Word_int
| Pbigarray_caml_int -> Word_int
| Pbigarray_native_int -> Word_int
| Pbigarray_complex32 -> Single
| Pbigarray_complex64 -> Double
let bigarray_get unsafe elt_kind layout b args dbg =
bind "ba" b (fun b ->
match (elt_kind : Lambda.bigarray_kind) with
Pbigarray_complex32 | Pbigarray_complex64 ->
let kind = bigarray_word_kind elt_kind in
let sz = bigarray_elt_size elt_kind / 2 in
bind "addr"
(bigarray_indexing unsafe elt_kind layout b args dbg) (fun addr ->
bind "reval"
(Cop(mk_load_mut kind, [addr], dbg)) (fun reval ->
bind "imval"
(Cop(mk_load_mut kind,
[Cop(Cadda, [addr; Cconst_int (sz, dbg)], dbg)], dbg))
(fun imval -> box_complex dbg reval imval)))
| _ ->
Cop(mk_load_mut (bigarray_word_kind elt_kind),
[bigarray_indexing unsafe elt_kind layout b args dbg],
dbg))
let bigarray_set unsafe elt_kind layout b args newval dbg =
bind "ba" b (fun b ->
match (elt_kind : Lambda.bigarray_kind) with
Pbigarray_complex32 | Pbigarray_complex64 ->
let kind = bigarray_word_kind elt_kind in
let sz = bigarray_elt_size elt_kind / 2 in
bind "newval" newval (fun newv ->
bind "addr" (bigarray_indexing unsafe elt_kind layout b args dbg)
(fun addr ->
Csequence(
Cop(Cstore (kind, Assignment), [addr; complex_re newv dbg], dbg),
Cop(Cstore (kind, Assignment),
[Cop(Cadda, [addr; Cconst_int (sz, dbg)], dbg);
complex_im newv dbg],
dbg))))
| _ ->
Cop(Cstore (bigarray_word_kind elt_kind, Assignment),
[bigarray_indexing unsafe elt_kind layout b args dbg; newval],
dbg))
(* the three functions below assume 64-bit words *)
let () = assert (size_int = 8)
(* low_32 x is a value which agrees with x on at least the low 32 bits *)
let rec low_32 dbg = function
(* Ignore sign and zero extensions, which do not affect the low bits *)