Joseph Ferano
d6fc15474b
The author: "I think I prefer length over len, because then I'll use len as the variable name". One arm in check.ml, one row in the table beside it, and every (len x) in lib, test, examples, vendor, spike, docs, web, emacs, plan.org and NEXT.md rewritten. Shadowing and builtin/ had already taken most of the sting out: a (defn len ...) was legal and won in its own file, and builtin/len reached past it. What was left is that len was still a builtin — the defn earned a warning, and a wrapper had to say builtin/ at every inner call. Now there is nothing under the short name: len is an ordinary identifier in every position, which is what (let [len (length xs)] ...) wants. length takes over as shadowing's worked example rather than the feature losing one. shadow-builtin.flan, builtin-qualified.flan, pkgs/shadowed and the builtin/ rows in test_flan move to it and go on testing shadowing. A call to a len nothing defines is answered where an unknown function is, after every table and after the shadowing guard, so a program with its own len never reaches it. The sentence is said rather than guessed at — len and length are three edits apart and the did-you-mean's net is one — and the call is written back out through spell_arg, as-slice's spelling lifted out of it and now shared, so what is printed compiles. sand.flan:33 still calls the old name and is the author's to change; until it does, test_acceptance and test_session abort there. Both were run green against a copy with that one line changed. FIX.org says so.
172 lines
6.6 KiB
OCaml
172 lines
6.6 KiB
OCaml
(* What redefining a generic function costs the dev loop, measured.
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The question the spike exists to answer: C-c C-c on a concrete function is
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about 35 ms today, and a generic function that is redefined has to rebuild
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*every* instantiation. So the sweep is one generic called at N concrete
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types, N = 1..8, against the handwritten N-copies program it replaces, and
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the three things a C-c C-c actually pays for are timed separately:
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check Check.program_with_env over the whole accumulated program —
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which is what Session.eval does on every evaluation, so this is
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paid whether the redefined function is generic or not.
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emit Emit.redefinition for the fns being installed.
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build llc + ld -shared, from Build.shared — the dominant term.
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Nothing here modifies the session or the dev loop; it drives the real ones. *)
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let tys = [| "i8"; "i16"; "i32"; "i64"; "u8"; "u16"; "u32"; "f32" |]
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let time f =
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let t0 = Unix.gettimeofday () in
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let x = f () in
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(x, (Unix.gettimeofday () -. t0) *. 1000.)
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(* Best of k, because llc and the linker are processes and the machine is
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noisy; a median would hide a systematic cost and a mean would report the
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scheduler. *)
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let best k f =
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let rec go i acc = if i = 0 then acc else
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let _, ms = time f in go (i - 1) (min acc ms) in
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go k infinity
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let generic_src n =
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let b = Buffer.create 1024 in
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Buffer.add_string b
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"(defn gswap [xs [$t] i i32 j i32] ()\n\
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\ (let [tmp (at xs i)]\n\
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\ (set (at xs i) (at xs j))\n\
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\ (set (at xs j) tmp)))\n\n\
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(defn gsort [s [$t] before? (Fn [$t $t] bool)] ()\n\
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\ (let [i 1]\n\
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\ (while (< i (length s))\n\
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\ (let [j i]\n\
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\ (while (and (> j 0) (before? (at s j) (at s (- j 1))))\n\
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\ (gswap s (- j 1) j)\n\
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\ (set j (- j 1))))\n\
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\ (set i (+ i 1)))))\n\n";
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for i = 0 to n - 1 do
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Buffer.add_string b (Printf.sprintf "(defonce xs-%s [8 %s])\n" tys.(i) tys.(i))
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done;
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Buffer.add_string b "\n(defn main [] ()\n";
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for i = 0 to n - 1 do
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Buffer.add_string b
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(Printf.sprintf " (gsort (slice xs-%s 0 8) (fn [a b] (< a b)))\n" tys.(i))
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done;
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Buffer.add_string b " )\n";
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Buffer.contents b
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(* The same program as it is written today: one copy of each function per
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element type, by hand. This is prelude.ml's shape. *)
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let mono_src n =
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let b = Buffer.create 1024 in
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for i = 0 to n - 1 do
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let t = tys.(i) in
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Buffer.add_string b
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(Printf.sprintf
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"(defn mswap-%s [xs [%s] i i32 j i32] ()\n\
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\ (let [tmp (at xs i)]\n\
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\ (set (at xs i) (at xs j))\n\
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\ (set (at xs j) tmp)))\n\n\
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(defn msort-%s [s [%s] before? (Fn [%s %s] bool)] ()\n\
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\ (let [i 1]\n\
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\ (while (< i (length s))\n\
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\ (let [j i]\n\
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\ (while (and (> j 0) (before? (at s j) (at s (- j 1))))\n\
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\ (mswap-%s s (- j 1) j)\n\
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\ (set j (- j 1))))\n\
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\ (set i (+ i 1)))))\n\n"
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t t t t t t t);
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Buffer.add_string b (Printf.sprintf "(defonce xs-%s [8 %s])\n\n" t t)
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done;
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Buffer.add_string b "(defn main [] ()\n";
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for i = 0 to n - 1 do
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Buffer.add_string b
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(Printf.sprintf " (msort-%s (slice xs-%s 0 8) (fn [a b] (< a b)))\n"
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tys.(i) tys.(i))
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done;
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Buffer.add_string b " )\n";
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Buffer.contents b
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let write path s =
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let oc = open_out path in output_string oc s; close_out oc
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let dir =
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let d = Filename.concat (Filename.get_temp_dir_name ()) "flan-generics-spike" in
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(try Unix.mkdir d 0o700 with Unix.Unix_error (Unix.EEXIST, _, _) -> ());
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d
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let decls_of path =
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(Flan.Load.program ~file:path
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(Flan.Parse.program (Flan.Reader.read_file path))).Flan.Load.decls
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(* Every function the program ended up with whose name starts with one of the
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generic names — the instantiations, which is exactly what a redefinition of
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the generic would have to rebuild. *)
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let instantiations (p : Flan.Tast.program) =
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List.filter_map
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(fun (f : Flan.Tast.fn) ->
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let n = f.Flan.Tast.name in
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if String.length n > 6 && String.sub n 0 6 = "gswap-" then Some n
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else if String.length n > 6 && String.sub n 0 6 = "gsort-" then Some n
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else None)
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p.Flan.Tast.fns
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let build_ms ir =
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let out = Filename.concat dir "redef.so" in
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best 3 (fun () ->
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ignore
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(Flan.Build.shared
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~opts:{ Flan.Build.default with dev = true } ~ir ~out ()))
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let () =
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Printf.printf
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"n check-gen check-mono emit-1 emit-N build-1 build-N fns\n";
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(try
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for n = 1 to 8 do
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let gpath = Filename.concat dir (Printf.sprintf "gen%d.flan" n) in
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let mpath = Filename.concat dir (Printf.sprintf "mono%d.flan" n) in
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write gpath (generic_src n);
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write mpath (mono_src n);
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let gd = decls_of gpath and md = decls_of mpath in
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let check_gen = best 3 (fun () -> ignore (Flan.Check.program_with_env gd)) in
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let check_mono = best 3 (fun () -> ignore (Flan.Check.program_with_env md)) in
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let p, _ = Flan.Check.program_with_env gd in
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let insts = instantiations p in
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let one = [ List.hd insts ] in
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let ir_one =
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Flan.Emit.redefinition ~dev:true ~known:(fun _ -> true) p ~fns:one
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in
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let ir_all =
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Flan.Emit.redefinition ~dev:true ~known:(fun _ -> true) p ~fns:insts
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in
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let emit1 =
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best 3 (fun () ->
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ignore (Flan.Emit.redefinition ~dev:true ~known:(fun _ -> true) p ~fns:one))
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and emitn =
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best 3 (fun () ->
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ignore (Flan.Emit.redefinition ~dev:true ~known:(fun _ -> true) p ~fns:insts))
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in
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let b1 = build_ms ir_one and bn = build_ms ir_all in
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Printf.printf "%d %8.1f %10.1f %7.1f %7.1f %8.1f %8.1f %d\n%!"
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n check_gen check_mono emit1 emitn b1 bn (List.length insts)
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done
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with Flan.Loc.Error d -> prerr_endline (Flan.Loc.report d); exit 1);
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(* And what the session actually does when the generic itself is redefined.
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This is the real C-c C-c path — Session.eval on the form the editor sent
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— and what it reports is the finding, not the timing. *)
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let gpath = Filename.concat dir "gen4.flan" in
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let t, _ = Flan.Session.create ~file:gpath () in
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let form =
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"(defn gswap [xs [$t] i i32 j i32] ()\n\
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\ (let [tmp (at xs i)]\n\
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\ (set (at xs i) (at xs j))\n\
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\ (set (at xs j) tmp)))\n"
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in
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let c, ms = time (fun () -> Flan.Session.eval ~origin:gpath t form) in
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Printf.printf
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"\nSession.eval on the generic gswap itself: %.1f ms, installs=%b, \
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fns=[%s], names=[%s]\n"
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ms c.Flan.Session.installs
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(String.concat " " c.Flan.Session.fns)
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(String.concat " " c.Flan.Session.names)
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