Joseph Ferano
fc319474b6
PORTING.md Tier 1 item 5. The spy half of the watch was already built — the pushed table, the buffer, the inline ghost text. What was missing is spy-num, which is the part that item calls least obvious and most valuable, and it is what this is. A slot keeps count, min, max, last and mean. Each answers a question you can ask without building a query: n is the first thing wrong when a loop is wrong, the range is what one sample can never show you, last is what the scalar watch would have given you, and the mean is a running sum divided at read time because a mean accumulated as a mean drifts. A small ring of the last N samples was the other candidate and loses — N out of 91,200 is a sample of the tail of the loop rather than of the loop, and past five numbers every richer answer is a UI for building a query. The write path does no formatting, which is the feature rather than an optimisation: a snprintf per sample at thousands a frame is a HUD that costs more than the game. A sample is a load, five compares and the slot's seqlock; the listener thread renders once per editor tick. The window is since the editor's last tick, and that is a deliberate divergence from watch.clj, where the stats are cumulative until reset-spies!. Cumulative min and max reach the session's extremes within seconds of play and then never move again, so the two most useful of the five go dead exactly when you start interacting with the thing you are debugging — and this tool exists to show you a number while you drag the mouse. Reset is its own message and never a side effect of reading, because a destructive read makes looking change what is there and anything that polls would shorten the window under the editor that owns it. It bumps one epoch counter and clears no slot; a slot clears itself on its next sample, so the reader never writes the table. Ghost text needed one character. The call regexp allowed one hyphenated segment, so watch-num-i64 backtracked to failure and a numeric watch got no inline value while appearing normally in the buffer. dune test is green, run twice. HANDOFF-f3.md carries the reasoning, the two small gaps left behind it, and what did not work on the way.
2408 lines
110 KiB
OCaml
2408 lines
110 KiB
OCaml
(** [flan dev]: one long-lived session, the program it belongs to running
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beside it, and a socket an editor talks to.
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This is the piece between an editor and everything else. What it adds over
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[flan reload] is that the session *persists*: a [defvar] added by one
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evaluation is part of the program the next one is checked against, and the
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set of names the running process was built with is the one from the build
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this daemon actually made. A CLI that rebuilds its session from source each
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time cannot have either.
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It owns the build, which is what makes its layout rules mean anything: a
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session's struct layouts and global types describe the memory of a process
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only if it is the session that compiled it. So the daemon launches the
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program rather than attaching to one. *)
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(* Where a function's body was last built. The daemon owns the build, so it is
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the only thing that can answer "which module defines this name now" — but
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see [basis] below for what that answer honestly is. *)
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type origin = {
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ogen : int; (* reload generation; 0 is the host's *)
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oso : string; (* the object the body was linked into *)
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oll : string; (* the IR it was built from *)
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oloc : string; (* where the source it came from was written *)
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}
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type t = {
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session : Session.t;
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(* The running program. [Some pid] is the two-process daemon, which launched
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it; [None] is the merged build, where the program is *this* process and
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the compiler is a thread inside it. That is the whole of the difference at
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this layer — see [merged_setup] for why there is no third case. *)
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child : int option;
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agent : string; (* where it listens for modules *)
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dir : string; (* modules are built here, one per eval *)
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stdout : Unix.file_descr; (* the program's output, on its way to here *)
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out : Buffer.t; (* ...buffered until an editor asks for it *)
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mutable n : int; (* dlopen caches by path: never reuse one *)
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(* Bookkeeping for disassembly, and the reason it can exist at all: the
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daemon compiled every module it sent, so the .ll and the .so are on its
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own disk. What it does not have is a way back into the process's cells. *)
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mutable gen : int; (* accepted deliveries, in order *)
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owners : (string, origin) Hashtbl.t; (* fn name -> the last module sent *)
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host_ll : string; (* the IR the running program was built from *)
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host_exe : string; (* ...and the binary it was linked into *)
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(* Set when the program's stdout reads EOF. In the two-process daemon that
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happens because the child died and [waitpid] is the authority anyway; in
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the merged build it is the signal itself — the program's exit closes fd 1
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and parks, and this is how the compiler finds out. *)
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mutable finished : bool;
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}
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(* The program's stdout is a pipe into this process, so that an editor can see
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it. That makes draining it a *liveness* requirement and not a nicety: a pipe
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nobody reads fills at 64K and the next write blocks the program forever. So
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it is read from the accept loop's select, not only when someone asks. *)
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let capacity = 256 * 1024
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let drain t =
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let b = Bytes.create 8192 in
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let rec go () =
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match Unix.select [ t.stdout ] [] [] 0. with
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| [], _, _ -> ()
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| _ ->
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(match Unix.read t.stdout b 0 8192 with
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(* EOF on a pipe: every writer is gone, so the program has finished. *)
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| 0 -> t.finished <- true
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| n ->
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Buffer.add_subbytes t.out b 0 n;
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(* Bounded: a program that prints every frame must not grow this
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process without limit. The newest text is the useful end. *)
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if Buffer.length t.out > capacity then begin
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let keep = Buffer.sub t.out (Buffer.length t.out - capacity) capacity in
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Buffer.clear t.out;
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Buffer.add_string t.out keep
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end;
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go ()
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| exception Unix.Unix_error (Unix.EAGAIN, _, _) -> ()
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| exception Unix.Unix_error (Unix.EWOULDBLOCK, _, _) -> ()
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| exception Unix.Unix_error _ -> ())
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in
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go ()
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let take t =
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drain t;
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let s = Buffer.contents t.out in
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Buffer.clear t.out;
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s
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let await ?(ms = 5000) f =
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let rec go ms =
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if f () then true
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else if ms <= 0 then false
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else begin ignore (Unix.select [] [] [] 0.005); go (ms - 5) end
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in
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go ms
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(* ── Asking the agent ──────────────────────────────────────────────── *)
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(* One line out, one line back. The agent is not a protocol and must not become
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one, and every verb below goes through here.
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Two ways to ask, and the caller cannot tell them apart. In a merged build
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the agent is in this process and the answer is a function call — the socket
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would be a connect, a write and a read looping back into this same address
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space, which is the transport the merge exists to remove. In
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[--two-process] there is no agent here, so it is the socket, exactly as
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before.
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Which one is not a flag: [Agent.request] is [None] when the linker resolved
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a weak symbol to null, so it is [None] in precisely the binaries that have
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no agent to call. A flag could disagree with reality; this cannot. *)
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let over_socket t line =
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let s = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
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Fun.protect
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~finally:(fun () -> try Unix.close s with Unix.Unix_error _ -> ())
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(fun () ->
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Unix.connect s (Unix.ADDR_UNIX t.agent);
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let msg = line ^ "\n" in
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ignore (Unix.write_substring s msg 0 (String.length msg));
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let b = Bytes.create 4096 in
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let buf = Buffer.create 256 in
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let rec drain () =
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match Unix.read s b 0 4096 with
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| 0 -> ()
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| n -> Buffer.add_subbytes buf b 0 n; drain ()
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| exception Unix.Unix_error _ -> ()
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in
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drain ();
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Buffer.contents buf)
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let request t line =
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match Agent.request line with
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| Some answer -> answer
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| None -> over_socket t line
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(* ── Delivery ──────────────────────────────────────────────────────── *)
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(* The agent answers "ok" when it has queued a module, and anything else is a
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refusal with a reason. Reporting that back rather than swallowing it is what
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keeps a failed delivery from looking like a successful evaluation — the
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whole class of bug this hand-off makes possible.
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"Queued", still, and not "installed", in one process as in two: the store
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happens on the game thread at a frame boundary, and a direct call that
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installed on the spot would be a frame running half in the old code and half
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in the new. *)
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let deliver t path = String.trim (request t path)
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(* Read back the value of the last expression evaluated, with the counter that
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says whether it is a new one. The thunk runs on the game thread whenever the
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program next reaches a frame boundary, which is not a moment the compiler
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gets to know about, so this waits for the counter to move rather than
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assuming it has. *)
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let result t =
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let text = request t "result" in
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match String.index_opt text '\n' with
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| None -> None
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| Some i ->
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let header = String.sub text 0 i in
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let body = String.sub text (i + 1) (String.length text - i - 1) in
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(match String.split_on_char ' ' header with
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| [ g; _ ] ->
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(match Int64.of_string_opt g with
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| Some g -> Some (g, body)
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| None -> None)
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| _ -> None)
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(* ── The break state ───────────────────────────────────────────────── *)
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(* Everything above is about changing a *running* program. This is the other
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half: an unhandled [error] does not kill a dev build, it stops the game
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thread on the frame that erred and waits. The agent is where that shows, and
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the session is the only thing holding it — so an editor asks here or not at
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all. *)
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let ask t verb = request t verb
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type state =
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| Running
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| Stopped of string (* the condition's class name *)
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| Unreachable of string (* no answer: exited, or never listened *)
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(* [status] is answered whether or not the program is stopped — "running" is an
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answer, not a refusal. Everything else the break loop offers is refused
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while running, and rightly: there is no restart stack to walk. But the
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question an editor asks *without already knowing* is this one, so it had to
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have an answer in both states or there would be nothing to poll. *)
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let state t =
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match ask t "status" with
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| "" -> Unreachable "the program is not answering on its socket"
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| text ->
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let line = String.trim (List.hd (String.split_on_char '\n' text)) in
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if line = "running" then Running
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else if String.length line > 8 && String.sub line 0 8 = "stopped " then
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Stopped (String.sub line 8 (String.length line - 8))
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else Unreachable ("the program answered " ^ line)
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| exception Unix.Unix_error (e, _, _) -> Unreachable (Unix.error_message e)
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(* Innermost first, terminated by a line that is a single dot — the agent's
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framing, not this one's. A refusal comes back as a line starting "err ", and
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is passed on rather than turned into an empty list: no restarts and cannot
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say are different answers.
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Each line is [I ± NAME]: the index it is taken by, whether it can be taken,
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and the name. The index is the identity — two frames may offer [retry] and
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a name cannot say which — and it is the program's number, not this end's
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position in a list, so it is carried rather than recomputed. *)
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let restarts t =
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match ask t "restarts" with
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| text ->
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let lines = String.split_on_char '\n' text in
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if List.exists (fun l -> String.length l >= 3 && String.sub l 0 3 = "err") lines
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then Error (String.trim text)
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else begin
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let parse line =
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match String.index_opt line ' ' with
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| None -> None
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| Some i ->
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(match int_of_string_opt (String.sub line 0 i) with
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| None -> None
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| Some idx ->
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let rest = String.sub line (i + 1) (String.length line - i - 1) in
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if String.length rest < 2 then None
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else
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Some
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( idx,
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rest.[0] = '+',
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String.sub rest 2 (String.length rest - 2) ))
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in
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Ok
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(List.filter_map parse
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(List.filter
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(fun l -> l <> "" && l <> ".")
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(List.map String.trim lines)))
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end
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| exception Unix.Unix_error (e, _, _) -> Error (Unix.error_message e)
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(* Where a stopped program is, one frame per line, innermost first — the same
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framing [restarts] uses, terminated by a lone dot, because it comes back
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over the same one-line-out socket.
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Each line is [I ± NSLOTS SIG RSIG LOC NAME]. [SIG] is the slot fingerprint
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of the body this frame was compiled from — [Emit.slot_fingerprint] over the
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name and the type of every slot — and it is how [locals] tells a frame whose
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body has been redefined underneath it from one that still matches. [RSIG] is
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[Reach.ref_fingerprint] over the globals that body names, which is the same
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question asked about a different part of the body: the slots can be
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identical while the globals are not, and then it is the globals section that
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must not trust the frame while [locals] still can. Both stay off the wire: a
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hash is not something a client can act on, and the refusals they produce say
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the fact in words instead. They sit before [LOC] because [NAME] is the only
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field that can contain a space and so has to be last.
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The flag says whether the frame belongs
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to the program or to the C-x C-e thunk the break happens to be inside: a
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break inside an evaluation has that evaluation's frames on top, and
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answering "where is my program" with [eval/7] would be true and useless.
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[LOC] is the frame's own — it travels in the module that defined the body,
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so a redefined function reports where the *installed* body is written and
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not where the one this daemon first built was. A frame with none says [?].
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A truncated backtrace ends [... N] before the dot; deep recursion is the
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case, and the innermost frames are the ones the question is about. *)
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let backtrace t =
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match ask t "backtrace" with
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| text ->
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let lines =
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List.map String.trim (String.split_on_char '\n' text)
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in
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if List.exists (fun l -> String.length l >= 3 && String.sub l 0 3 = "err") lines
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then Error (String.trim text)
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else begin
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let more = ref 0 in
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let parse line =
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if String.length line > 4 && String.sub line 0 4 = "... " then begin
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(match int_of_string_opt (String.sub line 4 (String.length line - 4)) with
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| Some n -> more := n
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| None -> ());
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None
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end
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else
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match String.split_on_char ' ' line with
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| idx :: flag :: nslots :: sig_ :: rsig :: loc :: rest when rest <> [] ->
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(match
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int_of_string_opt idx, int_of_string_opt nslots,
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int_of_string_opt sig_, int_of_string_opt rsig
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with
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| Some _, Some k, Some g, Some r ->
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Some (String.concat " " rest, (if loc = "?" then "" else loc),
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flag = "+", k, g, r)
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| _ -> None)
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| _ -> None
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in
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let frames =
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List.filter_map parse
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(List.filter (fun l -> l <> "" && l <> ".") lines)
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in
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Ok (frames, !more)
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end
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| exception Unix.Unix_error (e, _, _) -> Error (Unix.error_message e)
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(* Which of a frame's slots have been reached. One line per slot, [I ±], the
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same framing as everything else the agent answers.
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Asked before a thunk is built rather than after: an unbound slot is a null
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address, and a thunk that rendered one would take a fault on the game
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thread of a program that is already stopped — which is the one place a
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crash costs the most, because it is where someone is standing over the
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wreck deciding what to do about it. *)
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let bound_slots t ~frame =
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match ask t (Printf.sprintf "locals %d" frame) with
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| text ->
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let lines = List.map String.trim (String.split_on_char '\n' text) in
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if List.exists (fun l -> String.length l >= 3 && String.sub l 0 3 = "err") lines
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then Error (String.trim text)
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else
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Ok
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(List.filter_map
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(fun l ->
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match String.split_on_char ' ' l with
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| [ i; "+" ] -> int_of_string_opt i
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| _ -> None)
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(List.filter (fun l -> l <> "" && l <> ".") lines))
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| exception Unix.Unix_error (e, _, _) -> Error (Unix.error_message e)
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(* In the merged build the program is this process, so the question answers
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itself: if this code is running, so is the program. The two-process daemon
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has to ask the kernel. *)
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let alive t =
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match t.child with
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| None -> not t.finished
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| Some child ->
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(match Unix.waitpid [ Unix.WNOHANG ] child with
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| 0, _ -> true
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| _ -> false
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| exception Unix.Unix_error _ -> false)
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(* ── What a body was built from ─────────────────────────────────────── *)
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let write_file path text =
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let oc = open_out_bin path in
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Fun.protect ~finally:(fun () -> close_out oc) (fun () -> output_string oc text)
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let read_file path =
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let ic = open_in_bin path in
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Fun.protect
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~finally:(fun () -> close_in ic)
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(fun () -> really_input_string ic (in_channel_length ic))
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let find_fn t name =
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List.find_opt
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(fun (f : Tast.fn) ->
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String.equal f.Tast.name name && f.Tast.fparent = None)
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t.session.Session.program.Tast.fns
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let fn_loc t name =
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match find_fn t name with
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| Some f -> Loc.to_string f.Tast.floc
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| None -> ""
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(* Where the *running process* has this function written, which is not where
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the session has it. [Session.eval] replaces the checked program as soon as a
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form checks — before the build, before delivery — so a body that checked and
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then failed to build leaves the session holding a location in a buffer whose
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code never landed. [host] is the program the process was launched from and
|
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nothing mutates it, so it is the only honest answer for a name no module has
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been accepted for. *)
|
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let host_loc t name =
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match
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List.find_opt
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(fun (f : Tast.fn) ->
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String.equal f.Tast.name name && f.Tast.fparent = None)
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t.session.Session.host.Tast.fns
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with
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| Some f -> Loc.to_string f.Tast.floc
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| None -> ""
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|
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(* ── Ops ───────────────────────────────────────────────────────────── *)
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|
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(* Every reply is a plist with a :status, so an editor can dispatch on one key
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and never has to guess whether a missing field means failure. *)
|
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let ok fields =
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"(:status \"ok\"" ^ String.concat "" (List.map (fun f -> " " ^ f) fields) ^ ")"
|
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|
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(* Anything the program printed since the last reply rides along with this one.
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An editor that had to ask separately would miss the output an evaluation
|
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itself caused, which is the output anyone actually wants to see. *)
|
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let with_output t reply =
|
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match take t with
|
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| "" -> reply
|
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| text ->
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let i = String.length reply - 1 in
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String.sub reply 0 i ^ " :output " ^ Wire.quote text ^ ")"
|
|
|
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(* The break state rides along with every reply, exactly as the program's own
|
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output does, and for the same reason: a program can stop at any moment and
|
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nothing in a request/response protocol will mention it unless every response
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does. An editor that had to *ask* would find out about a stop only when it
|
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happened to wonder — and the most common moment for a program to stop is the
|
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instant after an evaluation, which is a reply it is already reading.
|
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|
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It is the annotation, not the ops, that decides these two fields, so that
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there is one place in the daemon that says whether the program is stopped
|
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and the break ops cannot disagree with the poll. *)
|
|
let with_break t reply =
|
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let fields =
|
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match state t with
|
|
| Stopped c -> " :stopped t :condition " ^ Wire.quote c
|
|
| Running -> " :stopped nil"
|
|
(* Unreachable is not "running": the honest shape of "it exited" is
|
|
[:alive nil] from [describe], and claiming a state we could not read
|
|
would be the [ok]-means-probably failure in miniature. *)
|
|
| Unreachable _ -> " :stopped nil"
|
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in
|
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String.sub reply 0 (String.length reply - 1) ^ fields ^ ")"
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|
|
let error ?loc msg =
|
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"(:status \"error\" :message " ^ Wire.quote msg
|
|
^ (match loc with None -> "" | Some l -> " :loc " ^ Wire.quote l)
|
|
^ ")"
|
|
|
|
let eval t ~code ~origin =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else
|
|
match Session.eval ~origin t.session code with
|
|
| c when not c.Session.installs ->
|
|
(* Accepted into the session and nothing to send: a declaration the
|
|
program already has, with no body and no new storage. Saying "ok" and
|
|
shipping an empty module would report success for a change that cannot
|
|
have taken effect. *)
|
|
ok
|
|
[ ":names " ^ Wire.strings c.Session.names; ":fns ()";
|
|
":note " ^ Wire.quote "nothing to install" ]
|
|
| c ->
|
|
t.n <- t.n + 1;
|
|
let out = Filename.concat t.dir (Printf.sprintf "m%d.so" t.n) in
|
|
(* [Build.shared] deletes its own .ll unless asked to keep it, and what it
|
|
keeps is in a working directory named after this process rather than
|
|
after the module. Writing our own copy beside the .so is what makes
|
|
[disassemble] able to show the IR of a body installed ten reloads ago:
|
|
nothing else on this machine still has that text. *)
|
|
let ll = Filename.concat t.dir (Printf.sprintf "m%d.ll" t.n) in
|
|
write_file ll c.Session.ir;
|
|
(match Build.shared
|
|
~opts:{ Build.default with Build.dev = true;
|
|
Build.debug = t.session.Session.debug }
|
|
~ir:c.Session.ir ~out () with
|
|
| timing ->
|
|
(match deliver t out with
|
|
| "ok" ->
|
|
t.gen <- t.gen + 1;
|
|
List.iter
|
|
(fun n ->
|
|
Hashtbl.replace t.owners n
|
|
{ ogen = t.gen; oso = out; oll = ll; oloc = fn_loc t n })
|
|
c.Session.fns;
|
|
ok
|
|
[ ":names " ^ Wire.strings c.Session.names;
|
|
":fns " ^ Wire.strings c.Session.fns;
|
|
Printf.sprintf ":ms %.1f"
|
|
(timing.Build.llc_ms +. timing.Build.link_ms) ]
|
|
| reply -> error ("the program refused the module: " ^ reply)
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error
|
|
("cannot reach the program on " ^ t.agent ^ ": "
|
|
^ Unix.error_message e))
|
|
| exception Failure m -> error m)
|
|
| exception Loc.Error { Loc.dloc = l; dmsg = msg; _ } -> error ~loc:(Loc.to_string l) msg
|
|
|
|
(* Redefining a name installs a body; evaluating an expression has no name to
|
|
install into, so the module carries a thunk the agent runs once. The value
|
|
comes back through the runtime rather than through this reply, because the
|
|
frame boundary it runs at is the program's to choose. *)
|
|
let eval_expr t ~code ~origin =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else
|
|
match Session.eval_expr ~origin t.session code with
|
|
| c ->
|
|
let before = match result t with Some (g, _) -> g | None -> 0L in
|
|
t.n <- t.n + 1;
|
|
let out = Filename.concat t.dir (Printf.sprintf "e%d.so" t.n) in
|
|
(match Build.shared
|
|
~opts:{ Build.default with Build.dev = true;
|
|
Build.debug = t.session.Session.debug }
|
|
~ir:c.Session.ir ~out () with
|
|
| _ ->
|
|
(match deliver t out with
|
|
| "ok" ->
|
|
let rec wait ms =
|
|
match result t with
|
|
| Some (g, v) when Int64.compare g before > 0 -> Some v
|
|
| _ when ms <= 0 -> None
|
|
| _ ->
|
|
ignore (Unix.select [] [] [] 0.005);
|
|
if alive t then wait (ms - 5) else None
|
|
in
|
|
(match wait 5000 with
|
|
| Some v -> ok [ ":value " ^ Wire.quote v ]
|
|
| None ->
|
|
error
|
|
"the program did not reach a frame boundary; is it calling \
|
|
(agent/poll)?")
|
|
| reply -> error ("the program refused the module: " ^ reply)
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error ("cannot reach the program: " ^ Unix.error_message e))
|
|
| exception Failure m -> error m)
|
|
| exception Loc.Error { Loc.dloc = l; dmsg = msg; _ } -> error ~loc:(Loc.to_string l) msg
|
|
|
|
let describe t =
|
|
ok
|
|
[ ":fns "
|
|
^ Wire.strings
|
|
(List.map (fun (f : Tast.fn) -> f.Tast.name)
|
|
t.session.Session.program.Tast.fns);
|
|
":globals "
|
|
^ Wire.strings
|
|
(List.map (fun (g : Tast.global) -> g.Tast.gname)
|
|
t.session.Session.program.Tast.globals);
|
|
":alive " ^ (if alive t then "t" else "nil") ]
|
|
|
|
(* [describe] answers what exists; this answers what each one *is*. Its own op
|
|
rather than more fields on [describe], because [describe] is polled — an
|
|
editor uses it to drain the program's output — and this is asked once on
|
|
connect and again after each install. Putting signatures on the poll would
|
|
pay for them every time anyone looked at the output buffer.
|
|
|
|
One entry per name: (name kind signature loc). Four strings, so the editor
|
|
reads it with [read] and nothing here needs a new wire type. [loc] is empty
|
|
where there is none to give — only [Tast.fn] carries one — and an editor
|
|
that finds it empty must say so rather than guess a file.
|
|
|
|
Parameter *names* are not in the Tast, so a signature shows types only. *)
|
|
let signature_of_fn (f : Tast.fn) =
|
|
Printf.sprintf "%s [%s] %s" f.Tast.name
|
|
(String.concat " " (List.map Types.to_string f.Tast.params))
|
|
(Types.to_string f.Tast.ret)
|
|
|
|
let entry ~name ~kind ~sign ~loc =
|
|
Wire.list [ Wire.quote name; Wire.quote kind; Wire.quote sign; Wire.quote loc ]
|
|
|
|
let defs t =
|
|
let p = t.session.Session.program in
|
|
let fns =
|
|
List.filter_map
|
|
(fun (f : Tast.fn) ->
|
|
match f.Tast.fparent with
|
|
(* A handler-bind clause the checker lifted out. Nobody wrote this
|
|
name, so completing it is noise and jumping to it is meaningless. *)
|
|
| Some _ -> None
|
|
| None ->
|
|
Some
|
|
(entry ~name:f.Tast.name ~kind:"fn" ~sign:(signature_of_fn f)
|
|
~loc:(Loc.to_string f.Tast.floc)))
|
|
p.Tast.fns
|
|
in
|
|
let globals =
|
|
List.map
|
|
(fun (g : Tast.global) ->
|
|
entry ~name:g.Tast.gname
|
|
~kind:(if g.Tast.gconst then "const" else "var")
|
|
~sign:
|
|
(Printf.sprintf "%s %s" g.Tast.gname (Types.to_string g.Tast.gty))
|
|
~loc:"")
|
|
p.Tast.globals
|
|
in
|
|
let externs =
|
|
List.map
|
|
(fun (e : Tast.extern) ->
|
|
entry ~name:e.Tast.ename ~kind:"extern"
|
|
~sign:
|
|
(Printf.sprintf "%s [%s] %s" e.Tast.ename
|
|
(String.concat " " (List.map Types.to_string e.Tast.eparams))
|
|
(Types.to_string e.Tast.eret))
|
|
~loc:"")
|
|
p.Tast.externs
|
|
in
|
|
ok [ ":defs " ^ Wire.list (fns @ globals @ externs) ]
|
|
|
|
(* [(:op "layout" :type T)] — a struct's fields and their types.
|
|
|
|
The daemon can answer this with no running program at all: [Tast.structs] is
|
|
what it built the process from, and a layout is a fact about the build. That
|
|
is why it is the one thing the conditions buffer can fill in while the
|
|
condition's *values* stay refused.
|
|
|
|
**The type is a name, and the name is the qualified one.** [Load] qualifies
|
|
every declaration as it imports it — [Defstruct (qualify alias n, ...)] — so
|
|
the names in [Tast.structs] are a flat namespace in which two packages each
|
|
declaring [Missing] are [a/Missing] and [b/Missing] and no collision is
|
|
possible. That makes the name a type identity rather than a class name, with
|
|
no id table to keep in step, and it is the same string on both ends of the
|
|
wire already: [Emit.struct_name_of] puts [Types.Named n] into [flan_error],
|
|
the agent holds it in [condition_name], and [break] answers it as
|
|
[:condition]. Handing that string straight back as [:type] therefore
|
|
resolves, by construction.
|
|
|
|
A bare name is **refused, not resolved**, even when only one struct's last
|
|
segment matches: resolving it is exactly the ambiguity that made this op
|
|
need a rule, and a rule with an exception cannot be relied on by a client.
|
|
The refusal lists the qualified names it could have meant, so a person who
|
|
typed [Missing] is one copy-paste from the answer and a client can offer
|
|
them as completions.
|
|
|
|
Field types are spelled by [Types.to_string], which is what [defs] spells a
|
|
signature with — so [(Option T)], [[T]], [[n T]] and [(Ptr T)] read here
|
|
exactly as they read in a signature and in the source. A field that is
|
|
itself a struct shows its qualified name, which is a [:type] this op
|
|
accepts: nesting is another request rather than a second walk, and nothing
|
|
here can recurse forever. [Render] is the other walk over a type and is not
|
|
reused, because it walks a *value* and emits code that prints it; this emits
|
|
text about the type and never touches the program. *)
|
|
let layout t ~ty =
|
|
let structs = t.session.Session.program.Tast.structs in
|
|
match
|
|
List.find_opt (fun (s : Tast.structure) -> String.equal s.Tast.sname ty)
|
|
structs
|
|
with
|
|
| Some s ->
|
|
ok
|
|
[ ":type " ^ Wire.quote s.Tast.sname;
|
|
":fields "
|
|
^ Wire.list
|
|
(List.map
|
|
(fun (f : Tast.field) ->
|
|
Wire.list
|
|
[ Wire.quote f.Tast.fname;
|
|
Wire.quote (Types.to_string f.Tast.fty) ])
|
|
s.Tast.fields) ]
|
|
| None ->
|
|
(* Two types the checker knows and this op cannot describe. An enum's
|
|
members are erased to i32 before [Tast.program] exists, which is the
|
|
same fact that makes a defenum unreloadable; a union is declared and
|
|
has no values yet. Either way, saying which kind it is beats "no such
|
|
type" for a name that plainly exists. *)
|
|
if Hashtbl.mem t.session.Session.env.Check.enums ty then
|
|
error (ty ^ " is an enum, not a struct; its members are erased to i32")
|
|
else if
|
|
List.exists (fun (u : Tast.union) -> String.equal u.Tast.uname ty)
|
|
t.session.Session.program.Tast.unions
|
|
then
|
|
(* Unions have landed, so "milestone 6" was stale — but what replaces it
|
|
is not a layout. This op's reply is a flat [:fields] list, and a union
|
|
is a tag and one payload per case: there is no one field list to
|
|
answer with, and flattening the cases into one would describe storage
|
|
no value ever has. So it says which kind of type this is, and where
|
|
the question it was probably asked for *is* answered — the renderer
|
|
walks a union now, so a union value prints in a frame's locals and at
|
|
`C-x C-e' with its case and that case's fields. *)
|
|
error
|
|
(ty
|
|
^ " is a union, not a struct; a union is a tag and one payload per case, so it has no single field list for this op to answer with. Its value renders with its case and fields in a frame's locals and at C-x C-e")
|
|
else
|
|
let suffix = "/" ^ ty in
|
|
let candidates =
|
|
List.filter_map
|
|
(fun (s : Tast.structure) ->
|
|
let n = s.Tast.sname in
|
|
let k = String.length n - String.length suffix in
|
|
if k >= 0 && String.equal (String.sub n k (String.length suffix)) suffix
|
|
then Some n else None)
|
|
structs
|
|
in
|
|
(match candidates with
|
|
| [] -> error ("no struct is named " ^ ty)
|
|
| cs ->
|
|
(* Resolved on the client's side, deliberately: two packages can each
|
|
declare [Missing], and picking one of them here would answer a
|
|
layout for a type the asker did not mean. *)
|
|
"(:status \"error\" :message "
|
|
^ Wire.quote
|
|
(ty ^ " is not a qualified name; a package qualifies its \
|
|
declarations, so say which one")
|
|
^ " :candidates " ^ Wire.strings cs ^ ")")
|
|
|
|
(* What is on offer where the program stopped. [:stopped] and [:condition] are
|
|
not here: the annotation puts them on this reply as it puts them on every
|
|
other, so an editor reads the same two keys whatever it asked. What this op
|
|
adds is the restart names, which cost a second round trip to the program and
|
|
are wanted only when someone is about to choose one. *)
|
|
let break t =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else
|
|
match state t with
|
|
| Running -> ok []
|
|
| Unreachable m -> error ("cannot ask the program whether it stopped: " ^ m)
|
|
| Stopped _ ->
|
|
(match restarts t with
|
|
| Ok rs ->
|
|
(* [:restarts] stays a list of names, positional and innermost first,
|
|
with duplicates kept — the position *is* the index, which is what
|
|
[restart-at] takes. [:unreachable] names the positions that are on
|
|
the list and cannot be chosen: a restart below the evaluation the
|
|
break is inside has nowhere for a transfer to land. They are shown
|
|
rather than filtered, because a client that quietly dropped them
|
|
would leave someone asking where their restart went. *)
|
|
ok
|
|
[ ":restarts " ^ Wire.strings (List.map (fun (_, _, n) -> n) rs);
|
|
":unreachable "
|
|
^ Wire.ints
|
|
(List.filter_map
|
|
(fun (i, ok, _) -> if ok then None else Some i)
|
|
rs) ]
|
|
| Error m -> error ("the program refused to list its restarts: " ^ m))
|
|
|
|
(* [(:op "backtrace")] — the frames of a stopped program, innermost first.
|
|
NEXT.md's "Asked for by the editor lanes" had this blocked on exactly the
|
|
frame metadata the shadow stack now carries.
|
|
|
|
Refused while the program is running, and that is not a gap in the feature:
|
|
the chain is the game thread's, it is pushed and popped on every call, and
|
|
a walk of it from this end while that thread runs would produce a plausibly
|
|
shaped answer that was never true. Stopped, the thread is parked in the
|
|
break loop and the program itself takes the snapshot.
|
|
|
|
Each frame is [(name loc origin nslots)] — four fields in the shape [defs]
|
|
already uses, so an editor reads it with [read] and nothing else. [origin]
|
|
is "program" or "eval": a break inside a C-x C-e thunk has the thunk's
|
|
frames above the program's, and they are shown and labelled rather than
|
|
hidden, the same decision [:unreachable] makes for the restarts under one.
|
|
[nslots] is how many slots the frame has, which is what a client asks about
|
|
before asking for any of them. *)
|
|
let backtrace_op t =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else
|
|
match state t with
|
|
| Running ->
|
|
error
|
|
"the program is running; a backtrace is only taken while it is stopped, \
|
|
because the frame chain is the game thread's and it is changing"
|
|
| Unreachable m -> error ("cannot ask the program where it is: " ^ m)
|
|
| Stopped _ ->
|
|
(match backtrace t with
|
|
| Ok (frames, more) ->
|
|
ok
|
|
[ ":frames "
|
|
^ Wire.list
|
|
(List.map
|
|
(fun (name, loc, mine, nslots, _sig, _rsig) ->
|
|
Wire.list
|
|
[ Wire.quote name; Wire.quote loc;
|
|
Wire.quote (if mine then "program" else "eval");
|
|
string_of_int nslots ])
|
|
frames);
|
|
Printf.sprintf ":more %d" more ]
|
|
| Error m -> error ("the program refused to say where it is: " ^ m))
|
|
|
|
(* Build a render thunk, hand it to the program, and read back what it wrote.
|
|
|
|
The same five steps for every verb that renders something inside the
|
|
stopped program — [locals], [globals] and [inspect] — and they are here
|
|
once rather than three times because the note this file already carries
|
|
about the fingerprint applies to plumbing too: four of five hand-offs
|
|
present looks exactly like one hand-off dropping a step, and that is a bug
|
|
nobody sees until the one path that lost it is the one being used.
|
|
|
|
[tag] only names the [.so] on disk, which is what someone reads when they
|
|
go looking at [t.dir] to find out which verb produced what. *)
|
|
let run_render_thunk t ~tag ~(c : Session.change) : (string, string) result =
|
|
let before = match result t with Some (g, _) -> g | None -> 0L in
|
|
t.n <- t.n + 1;
|
|
let out = Filename.concat t.dir (Printf.sprintf "%s%d.so" tag t.n) in
|
|
match
|
|
Build.shared
|
|
~opts:{ Build.default with Build.dev = true;
|
|
Build.debug = t.session.Session.debug }
|
|
~ir:c.Session.ir ~out ()
|
|
with
|
|
| exception Failure m -> Error m
|
|
| _ ->
|
|
(match deliver t out with
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
Error ("cannot reach the program: " ^ Unix.error_message e)
|
|
| "ok" ->
|
|
let rec wait ms =
|
|
match result t with
|
|
| Some (g, v) when Int64.compare g before > 0 -> Some v
|
|
| _ when ms <= 0 -> None
|
|
| _ ->
|
|
ignore (Unix.select [] [] [] 0.005);
|
|
if alive t then wait (ms - 5) else None
|
|
in
|
|
(match wait 5000 with
|
|
| Some v -> Ok v
|
|
| None ->
|
|
Error
|
|
"the program did not reach a frame boundary; is it calling \
|
|
(agent/poll)?")
|
|
| reply -> Error ("the program refused the module: " ^ reply))
|
|
|
|
(* The frame checks, which every verb that reads a *frame* has to make and
|
|
must make the same way. [inspect] exists precisely because the listing is
|
|
frame-accurate and the inspector was not, so it sharing this function with
|
|
[locals] rather than repeating four conditions is the point: an inspector
|
|
that sidestepped the fingerprint would read stale slots out of a frame the
|
|
listing above it is already refusing.
|
|
|
|
[what] goes into the wording — "read slot names from" is not the sentence
|
|
[inspect] wants — and nothing else differs. *)
|
|
let stopped_frame t ~frame ~what : (string * Tast.fn, string) result =
|
|
if not (alive t) then Error "the program exited; restart flan dev"
|
|
else
|
|
match state t with
|
|
| Running ->
|
|
Error
|
|
(Printf.sprintf
|
|
"the program is running; %s is read from a stopped frame, and \
|
|
nothing in a frame that is still executing holds still"
|
|
what)
|
|
| Unreachable m -> Error ("cannot ask the program where it is: " ^ m)
|
|
| Stopped _ ->
|
|
(match backtrace t with
|
|
| Error m -> Error ("the program refused to say where it is: " ^ m)
|
|
| Ok (frames, _) ->
|
|
(match List.nth_opt frames frame with
|
|
| None ->
|
|
Error
|
|
(Printf.sprintf "there is no frame %d; the backtrace has %d" frame
|
|
(List.length frames))
|
|
| Some (name, _, mine, nslots, sig_, _rsig) ->
|
|
if not mine then
|
|
Error
|
|
(name
|
|
^ " is a frame of the expression this break is inside, not of the program; its thunk is not part of the session, so there is no record of what its slots are called")
|
|
else
|
|
match find_fn t name with
|
|
| None ->
|
|
Error
|
|
(name
|
|
^ " is not a function this session holds; a lifted handler clause has no declaration of its own to read slot names from")
|
|
| Some fn ->
|
|
(* The two body checks come first, including for a frame
|
|
with no slots. "every slot in it is one the compiler made
|
|
up" is a claim about the body this session holds, and a
|
|
zero-slot frame whose body has since been replaced by one
|
|
with slots is a frame that claim is false about. *)
|
|
if nslots <> Array.length fn.Tast.slots then
|
|
Error
|
|
(Printf.sprintf
|
|
"%s on the stack has %d slots and the %s this session holds has %d: the frame is running a body that has been redefined since, so every slot index here would be a guess"
|
|
name nslots name (Array.length fn.Tast.slots))
|
|
else if sig_ <> Emit.slot_fingerprint fn then
|
|
(* The count matching is not the same as the body matching.
|
|
A redefinition that renames a local, or changes its type
|
|
to one of the same shape, keeps the count — and then
|
|
every name here would be the new body's read against the
|
|
old body's storage, which is the "visible rather than
|
|
correct" answer this project refuses to give. Said by
|
|
name, because a frame that is missing and a frame that
|
|
cannot be trusted are different facts. *)
|
|
Error
|
|
(Printf.sprintf
|
|
"%s on the stack was compiled from a different body than the %s this session holds: this frame's body was redefined since it was entered, so its names no longer describe its values"
|
|
name name)
|
|
else Ok (name, fn)))
|
|
|
|
(* [(:op "locals" :frame N)] — what a stopped frame's named locals hold.
|
|
|
|
The half of a break loop that the author actually wanted, and the reason
|
|
the shadow stack was built rather than more DWARF: DWARF would have put
|
|
these in lldb, and the point is to need lldb less often.
|
|
|
|
Nothing is copied out of the program. A Flan value has no header, so bytes
|
|
read from another process would be bytes with no meaning; what this end has
|
|
is the *type* — [Tast.fn.slots], from the build it owns — and the name
|
|
beside it in [snames]. So it compiles a thunk that renders those types at
|
|
those addresses, in the program, on the stopped thread, and reads the text
|
|
back the way [C-x C-e] does. The only thing that comes from the running
|
|
program is where the frame is.
|
|
|
|
Three refusals, each by name and with its reason rather than by omission:
|
|
a slot the compiler invented and nobody named; a slot whose binding had not
|
|
run when the program stopped, which is a null address and would be a fault;
|
|
and a type the structural printer has no arm for. A local that is missing
|
|
and a local that could not be printed are different facts, and a list that
|
|
showed neither would be the same lie twice.
|
|
|
|
And two whole frames it refuses: one belonging to a [C-x C-e] thunk, which
|
|
this session does not keep the [Tast] of, and one whose *body* is not the
|
|
body this session holds. The second is the one that needed a fingerprint
|
|
rather than a count: installing while stopped is deliberately allowed — it
|
|
is the fix-it-and-retry loop — so the frame on the stack and the body here
|
|
can be two bodies of one function, and a redefinition that renames a local
|
|
changes neither the count nor the types. [Emit.slot_fingerprint] hashes
|
|
every slot's name together with the spelling of its type, the frame carries
|
|
the value for the body it was compiled from, and this end recomputes it
|
|
from the body it holds. A collision is possible in principle — it is a
|
|
30-bit hash — but only between two differing bodies of the function whose
|
|
qualified name already matched, since [find_fn] gates the comparison. *)
|
|
let locals t ~frame =
|
|
match stopped_frame t ~frame ~what:"locals" with
|
|
| Error m -> error m
|
|
| Ok (name, fn) ->
|
|
if Array.length fn.Tast.slots = 0 then
|
|
ok
|
|
[ ":frame " ^ Wire.quote name; ":locals ()"; ":refused ()";
|
|
":note "
|
|
^ Wire.quote
|
|
"that frame records no slots; every slot in it is one the compiler made up" ]
|
|
else
|
|
(match bound_slots t ~frame with
|
|
| Error m -> error ("the program refused to say which slots are bound: " ^ m)
|
|
| Ok bound ->
|
|
let c, refused = Session.render_locals t.session ~frame ~fn ~bound in
|
|
(match run_render_thunk t ~tag:"l" ~c with
|
|
| Error m -> error m
|
|
| Ok v ->
|
|
(* One line per slot — name, type, value, slot index — tab
|
|
separated, and safe because every string the renderer emits is
|
|
escaped. The index is last and it is what [i] in the break
|
|
buffer hands back to [inspect]: two slots can share a name, so
|
|
the name is not an identifier and the position in this list is
|
|
not one either, since a refused slot is not in it. *)
|
|
let entries =
|
|
List.filter_map
|
|
(fun line ->
|
|
match String.split_on_char '\t' line with
|
|
| [ n; ty; value; slot ] ->
|
|
Some
|
|
(Wire.list
|
|
[ Wire.quote n; Wire.quote ty; Wire.quote value; slot ])
|
|
| _ -> None)
|
|
(String.split_on_char '\n' v)
|
|
in
|
|
ok
|
|
[ ":frame " ^ Wire.quote name;
|
|
":locals " ^ Wire.list entries;
|
|
":refused "
|
|
^ Wire.list
|
|
(List.map
|
|
(fun (n, why) -> Wire.list [ Wire.quote n; Wire.quote why ])
|
|
refused) ]))
|
|
|
|
(* [(:op "inspect" :frame N :slot I :path (...))] — the inspector's second
|
|
rooting mode. [BUILT.md]'s "Two ways to root a walk" says what each root
|
|
can and cannot do; this is the half that names a frame.
|
|
|
|
[i] in the break buffer used to send a local's *name* to be evaluated as an
|
|
expression. On the innermost frame that happens to be right; on any other
|
|
it is evaluated wherever the evaluator stands, so it may resolve to a
|
|
global, to a different binding of the same name, or to nothing — with the
|
|
listing right above it showing the frame's own storage and nothing saying
|
|
the two disagree.
|
|
|
|
This roots the walk where the listing roots it: a frame and a slot index,
|
|
which is the address the shadow stack knows, plus the type [Tast.fn.slots]
|
|
knows. A step into a field is then an address plus an offset with that
|
|
field's type, which is arithmetic [Render.render] already does — see
|
|
[Session.render_slot], which is [render_locals] with a path applied to the
|
|
root and one line out instead of one per slot.
|
|
|
|
The frame checks are [locals]'s, by construction: both go through
|
|
[stopped_frame]. An inspector that made its own would be free to read a
|
|
frame whose body was redefined since it was entered, which is exactly the
|
|
stale-slot answer the listing refuses.
|
|
|
|
The slot is named by *index* and not by name, because a name is not unique:
|
|
[check.ml]'s [fresh_slot] only ever allocates, so (let [v 22] …) inside
|
|
(let [v 11] …) is two slots both called [v], and both are in the listing.
|
|
The index travels out with each line of [locals] for exactly this.
|
|
|
|
[:path] is a list the reader parses: a string is a field, an integer is an
|
|
element, and the symbol [some] is an option's payload. Empty means the slot
|
|
itself. *)
|
|
let inspect t ~frame ~slot ~path =
|
|
match stopped_frame t ~frame ~what:"a local" with
|
|
| Error m -> error m
|
|
| Ok (name, fn) ->
|
|
(match bound_slots t ~frame with
|
|
| Error m -> error ("the program refused to say which slots are bound: " ^ m)
|
|
| Ok bound ->
|
|
if not (List.mem slot bound) then
|
|
(* The same refusal the listing gives, and for the same reason: an
|
|
unbound slot's entry is null, and a thunk that rendered it would
|
|
fault on the game thread of a program that is already stopped. *)
|
|
error
|
|
(Printf.sprintf
|
|
"slot %d of %s was not bound yet at the point the program \
|
|
stopped; there is nothing at that address to read"
|
|
slot name)
|
|
else
|
|
match Session.render_slot t.session ~frame ~fn ~slot ~path with
|
|
| Error why -> error why
|
|
| Ok (c, label, ty) ->
|
|
(match run_render_thunk t ~tag:"i" ~c with
|
|
| Error m -> error m
|
|
| Ok v ->
|
|
(* One value and nothing else, so the whole of what came back is
|
|
it — minus the trailing newline the renderer does not write
|
|
here, because there is no second line to separate it from. *)
|
|
ok
|
|
[ ":frame " ^ Wire.quote name; ":name " ^ Wire.quote label;
|
|
":type " ^ Wire.quote ty; ":value " ^ Wire.quote v ]))
|
|
|
|
|
|
(* [(:op "globals")] — the globals the stopped stack reaches, in one section.
|
|
|
|
Locals were the half the shadow stack was built for; these are arguably the
|
|
more useful half in this language. A game keeps most of its state in
|
|
top-level [defvar]s and sand.flan holds its entire grid that way, so "what
|
|
is the program's state right now" is a question about globals and there was
|
|
nowhere to ask it.
|
|
|
|
**Not per frame, and that is the design.** A global is not part of a frame —
|
|
it is program state the frame happened to touch — so nesting it under one
|
|
implies an ownership that is not there, and repeats the name once per frame
|
|
that reads it. So: one section, whose contents are the union of the globals
|
|
every frame on the current stack references.
|
|
|
|
**The compiler does the choosing.** [Reach.expr_refs] is the walk that
|
|
already computes what a function refers to — it is how the link drops a
|
|
package nothing calls — and pointed at one body it answers that body's
|
|
reference set. Listing *all* of a program's globals instead would bury the
|
|
one that matters under the prelude's PRNG state; taking only what the stack
|
|
reaches is the filter the compiler can apply and a person cannot.
|
|
|
|
Direct references only, with no transitive closure through the calls a body
|
|
makes. A callee that reads a global is either on this stack — in which case
|
|
it is contributing its own references already — or it is not, in which case
|
|
it is not part of where the program stopped.
|
|
|
|
**Each entry says which frames touch it**, by index, which is what the stack
|
|
section already numbers them by. That recovers what per-frame nesting would
|
|
have told you — "the whole chain is reading this" reads differently from
|
|
"only the innermost does" — at no cost in duplication.
|
|
|
|
**Ordered by the innermost frame that touches it.** A deep stack makes the
|
|
union large, and proximity to the error is what puts the likely culprit on
|
|
top. Ties keep declaration order, which is the order the source has them in.
|
|
|
|
**A frame that cannot be attributed contributes nothing and says so.** An
|
|
eval frame has no declaration in this session; a lifted handler clause has
|
|
none of its own; and a frame whose body has been redefined since it was
|
|
entered holds a body whose reference set is a claim about different code.
|
|
In every case the honest answer is that the union is incomplete and which
|
|
frame made it so — [:skipped] — rather than a list that silently is not the
|
|
union it says it is. The *values* would still have been right; the
|
|
attribution is what goes wrong, and attribution is what this op is for.
|
|
|
|
**And the frame check that [locals]'s is not.**
|
|
[Emit.slot_fingerprint] hashes a body's *slots* — every slot's name with the
|
|
spelling of its type — so it catches a redefinition that binds differently
|
|
and misses one that does not. For [locals] that is exactly the right cut:
|
|
if the slots are identical then the names still describe the storage and
|
|
the answer is still true. Here it is not, because a body can change which
|
|
globals it names without touching a single slot, and then this section
|
|
would show the *new* body's reference set attributed to the *old* frame.
|
|
|
|
So a second fingerprint, [Reach.ref_fingerprint], over the set of globals
|
|
the body names, carried beside the slot one in [%fninfo] and checked here
|
|
the same way. Two numbers and not one, because they are two facts: a frame
|
|
whose slots match and whose globals do not has readable locals and
|
|
unusable attribution, and combining the hashes would make [locals] refuse
|
|
a frame nothing is wrong with. The values were never the exposure — they
|
|
come from the program's storage by name — and what was, one frame's
|
|
membership in the union and the frame numbers beside an entry, is now a
|
|
named refusal like every other.
|
|
|
|
Nothing is copied out of the program here either, and the mechanism is one
|
|
step simpler than [locals]: a global is reached by name rather than by
|
|
address, because [Emit.redefinition] writes a global the host already has as
|
|
[external] and the dynamic linker binds the thunk to the program's own
|
|
storage. So there is no [bound_slots] round trip and no not-yet-bound case —
|
|
a global's storage exists from the moment the process started. *)
|
|
let globals_op t =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else
|
|
match state t with
|
|
| Running ->
|
|
error
|
|
"the program is running; globals are read against a stopped stack, and \
|
|
the stack is what decides which of them to show"
|
|
| Unreachable m -> error ("cannot ask the program for its globals: " ^ m)
|
|
| Stopped _ ->
|
|
(match backtrace t with
|
|
| Error m -> error ("the program refused to say where it is: " ^ m)
|
|
| Ok (frames, _) ->
|
|
let all = t.session.Session.program.Tast.globals in
|
|
let is_global n =
|
|
List.exists (fun (g : Tast.global) -> String.equal g.Tast.gname n) all
|
|
in
|
|
(* name -> the frame indices that reference it, innermost lowest *)
|
|
let touched : (string, int list) Hashtbl.t = Hashtbl.create 32 in
|
|
let skipped = ref [] in
|
|
List.iteri
|
|
(fun i (name, _, mine, nslots, sig_, rsig) ->
|
|
let skip why =
|
|
skipped := (Printf.sprintf "%d: %s" i name, why) :: !skipped
|
|
in
|
|
if not mine then
|
|
skip
|
|
"a frame of the expression this break is inside, not of the \
|
|
program; its thunk is not part of the session, so there is no \
|
|
record of what it refers to"
|
|
else
|
|
match find_fn t name with
|
|
| None ->
|
|
skip
|
|
"not a function this session holds; a lifted handler clause \
|
|
has no declaration of its own to read references from"
|
|
| Some fn ->
|
|
if nslots <> Array.length fn.Tast.slots then
|
|
skip
|
|
"the frame is running a body that has been redefined \
|
|
since, so what this session holds is a different body's \
|
|
reference set"
|
|
else if sig_ <> Emit.slot_fingerprint fn then
|
|
skip
|
|
"this frame's body was redefined since it was entered, so \
|
|
what it refers to here is a claim about different code"
|
|
else if rsig <> Reach.ref_fingerprint ~is_global fn then
|
|
(* The check the slot fingerprint cannot make. A body that
|
|
binds the same locals and names different globals passes
|
|
every test above and is still the wrong body to read a
|
|
reference set out of: what would go into the union is
|
|
the *new* body's globals, attributed to the frame of the
|
|
old one, and the frame numbers beside an entry would say
|
|
a frame touches something it does not. The values are
|
|
not what breaks — those are read from the program's own
|
|
storage by name — so this refuses the frame's
|
|
attribution and nothing else. [locals] deliberately does
|
|
not make this check: the slots still describe the
|
|
storage, so that frame is still readable. *)
|
|
skip
|
|
"this frame's body names different globals than the one \
|
|
this session holds, so which globals it contributes to \
|
|
this union would be the new body's answer about the old \
|
|
body's frame"
|
|
else begin
|
|
(* Once per frame per name: a body that reads the grid in
|
|
four places touches it once as far as this is
|
|
concerned. *)
|
|
let seen = Hashtbl.create 8 in
|
|
let note n =
|
|
if is_global n && not (Hashtbl.mem seen n) then begin
|
|
Hashtbl.add seen n ();
|
|
let prev =
|
|
try Hashtbl.find touched n with Not_found -> []
|
|
in
|
|
Hashtbl.replace touched n (prev @ [ i ])
|
|
end
|
|
in
|
|
List.iter (Reach.expr_refs note) fn.Tast.body;
|
|
List.iter (Reach.expr_refs note) fn.Tast.fdefers
|
|
end)
|
|
frames;
|
|
let skipped = List.rev !skipped in
|
|
let wanted =
|
|
(* Declaration order first, so a tie on the innermost frame breaks
|
|
the way the source reads. [stable_sort] then keeps it. *)
|
|
List.filter
|
|
(fun (g : Tast.global) -> Hashtbl.mem touched g.Tast.gname)
|
|
all
|
|
in
|
|
let innermost (g : Tast.global) =
|
|
List.fold_left min max_int (Hashtbl.find touched g.Tast.gname)
|
|
in
|
|
let ordered =
|
|
List.stable_sort
|
|
(fun a b -> compare (innermost a) (innermost b))
|
|
wanted
|
|
in
|
|
let where (g : Tast.global) =
|
|
Wire.list
|
|
(List.map string_of_int
|
|
(List.sort_uniq compare (Hashtbl.find touched g.Tast.gname)))
|
|
in
|
|
let skipped_field =
|
|
":skipped "
|
|
^ Wire.list
|
|
(List.map
|
|
(fun (n, why) -> Wire.list [ Wire.quote n; Wire.quote why ])
|
|
skipped)
|
|
in
|
|
if ordered = [] then
|
|
ok
|
|
[ ":globals ()"; ":refused ()"; skipped_field;
|
|
":note "
|
|
^ Wire.quote
|
|
"no frame on this stack references a global; there is \
|
|
nothing here that is not already in the locals" ]
|
|
else begin
|
|
let c, refused = Session.render_globals t.session ~globals:ordered in
|
|
match run_render_thunk t ~tag:"g" ~c with
|
|
| Error m -> error m
|
|
| Ok v ->
|
|
(* One line per global, name and type and value, tab separated —
|
|
safe because every string the renderer emits is escaped. The
|
|
frames are added back here, from the table above, because the
|
|
thunk knows nothing about the stack it was chosen for. *)
|
|
let by_name = Hashtbl.create 32 in
|
|
List.iter
|
|
(fun (g : Tast.global) ->
|
|
Hashtbl.replace by_name g.Tast.gname (where g))
|
|
ordered;
|
|
let entries =
|
|
List.filter_map
|
|
(fun line ->
|
|
match String.split_on_char '\t' line with
|
|
| [ n; ty; value ] ->
|
|
Some
|
|
(Wire.list
|
|
[ Wire.quote n; Wire.quote ty; Wire.quote value;
|
|
(try Hashtbl.find by_name n
|
|
with Not_found -> Wire.list []) ])
|
|
| _ -> None)
|
|
(String.split_on_char '\n' v)
|
|
in
|
|
ok
|
|
[ ":globals " ^ Wire.list entries;
|
|
":refused "
|
|
^ Wire.list
|
|
(List.map
|
|
(fun (n, why) -> Wire.list [ Wire.quote n; Wire.quote why ])
|
|
refused);
|
|
skipped_field ]
|
|
end)
|
|
|
|
(* A choice is validated by the *program*, on its listener thread, against a
|
|
stack the stopped game thread is holding still — not here. The daemon has no
|
|
copy of that stack and anything it checked would be a guess that was true a
|
|
moment ago.
|
|
|
|
"ok" therefore means accepted, and says so: the resume happens when the
|
|
stopped thread next comes round its loop, which is microseconds away and
|
|
still not now. An editor that read [ok] as "running again" would poll once,
|
|
find it stopped, and re-open the prompt it had just answered. *)
|
|
let choose_at t ~index ~name =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else if
|
|
match name with
|
|
| Some n -> String.exists (fun c -> Char.code c < 32 || Char.code c = 127) n
|
|
| None -> false
|
|
then error "a restart name cannot contain a control character"
|
|
else
|
|
let verb =
|
|
"restart-at " ^ string_of_int index
|
|
^ match name with Some n -> " " ^ n | None -> ""
|
|
in
|
|
match ask t verb with
|
|
| reply when String.trim reply = "ok" ->
|
|
ok
|
|
[ ":index " ^ string_of_int index;
|
|
":note "
|
|
^ Wire.quote
|
|
"accepted; the program resumes at its next pass of the break loop"
|
|
]
|
|
| reply -> error (String.trim reply)
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error ("cannot reach the program: " ^ Unix.error_message e)
|
|
|
|
let choose t ~name =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else if String.exists (fun c -> Char.code c < 32 || Char.code c = 127) name then
|
|
(* The agent's contract is one line per request. A name carrying a newline
|
|
would be a second request smuggled into the first, and the guarantee is
|
|
this end's to keep: [completing-read] cannot produce one, but the daemon
|
|
is what holds the socket and an editor is not the only thing that can
|
|
speak to it. *)
|
|
error "a restart name cannot contain a control character"
|
|
else
|
|
match ask t ("restart " ^ name) with
|
|
| reply when String.trim reply = "ok" ->
|
|
ok
|
|
[ ":restart " ^ Wire.quote name;
|
|
":note "
|
|
^ Wire.quote "accepted; the program resumes at its next pass of the break loop" ]
|
|
| reply -> error (String.trim reply)
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error ("cannot reach the program: " ^ Unix.error_message e)
|
|
|
|
(* The other way out. The program exits 134 where it stopped, which ends this
|
|
daemon too — it owns the program's lifetime and has nothing left to serve.
|
|
Refused while running, by the program, for the same reason a restart is. *)
|
|
let abort t =
|
|
if not (alive t) then error "the program exited; restart flan dev"
|
|
else
|
|
match ask t "abort" with
|
|
| reply when String.trim reply = "ok" ->
|
|
ok [ ":note " ^ Wire.quote "the program is exiting; flan dev ends with it" ]
|
|
| reply -> error (String.trim reply)
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error ("cannot reach the program: " ^ Unix.error_message e)
|
|
|
|
(* ── Disassembly ───────────────────────────────────────────────────── *)
|
|
|
|
(* [flan emit --dev] can print the IR of a whole source file, which is a
|
|
different question from the one an editor asks: not "what would this compile
|
|
to" but "what is the code the running program is calling for this name".
|
|
Only the daemon can answer that, because it built every module it sent and
|
|
still has the .ll and the .so on disk.
|
|
|
|
What it cannot do is read a cell back. The agent's socket takes a module
|
|
path, [result], [status], [restarts], [restart] and [abort] — there is no
|
|
verb that reports an address, [flan_dev_cell] lives in the program's address
|
|
space, and an expression evaluated through [eval-expr] renders a pointer as
|
|
[<ptr>] on purpose. So the answer is the last module *delivered* for the
|
|
name, and the reply says exactly that rather than implying more; see
|
|
[basis]. The one case that is certain is the case where nothing has been
|
|
delivered at all, and it says that too.
|
|
|
|
SBCL's presentation is worth two things here and not a third. Offsets from
|
|
the function's own start rather than file addresses, because an address into
|
|
a .so means nothing to a reader; and labels for branch targets inside the
|
|
function, which is most of the difference between readable and not. The
|
|
third is source interleaving, which SBCL can do because it has the mapping
|
|
and this build has no line tables — so it is refused by name in the reply
|
|
instead of being faked by printing the listing with no source in it. *)
|
|
|
|
let objdump = try Sys.getenv "FLAN_OBJDUMP" with Not_found -> "objdump"
|
|
|
|
let run_capture cmd =
|
|
let ic = Unix.open_process_in (cmd ^ " 2>&1") in
|
|
let b = Buffer.create 4096 in
|
|
let chunk = Bytes.create 4096 in
|
|
let rec go () =
|
|
match input ic chunk 0 4096 with
|
|
| 0 -> ()
|
|
| n -> Buffer.add_subbytes b chunk 0 n; go ()
|
|
| exception End_of_file -> ()
|
|
in
|
|
go ();
|
|
let code = match Unix.close_process_in ic with Unix.WEXITED c -> c | _ -> -1 in
|
|
(code, Buffer.contents b)
|
|
|
|
let contains hay needle =
|
|
let n = String.length needle and h = String.length hay in
|
|
let rec go i = i + n <= h && (String.sub hay i n = needle || go (i + 1)) in
|
|
n = 0 || go 0
|
|
|
|
(* The IR of one function out of a module's text. [Emit] writes a define's
|
|
closing brace at column 0 and nowhere else, so the end is unambiguous
|
|
without parsing LLVM. One .ll can carry several bodies — [C-c C-k] sends a
|
|
buffer's worth as one module — which is why this slices rather than
|
|
returning the file. *)
|
|
let ir_of ~ir name =
|
|
let sym = Emit.fname name in
|
|
let rec take = function
|
|
| [] -> []
|
|
| "}" :: _ -> [ "}" ]
|
|
| l :: rest -> l :: take rest
|
|
in
|
|
let rec find = function
|
|
| [] -> None
|
|
| l :: rest ->
|
|
if String.length l > 7 && String.sub l 0 7 = "define " && contains l (sym ^ "(")
|
|
then Some (String.concat "\n" (take (l :: rest)))
|
|
else find rest
|
|
in
|
|
find (String.split_on_char '\n' ir)
|
|
|
|
(* objdump's own output, rebased and labelled. A line is
|
|
[" 250:<tab>bytes<tab>mnemonic"], with a continuation line carrying only
|
|
bytes when an instruction's encoding does not fit the column. *)
|
|
type insn = { off : int; bytes : string; text : string }
|
|
|
|
let parse_listing ~sym text =
|
|
let head = "<" ^ sym ^ ">:" in
|
|
let lines = String.split_on_char '\n' text in
|
|
let rec drop = function
|
|
| [] -> []
|
|
| l :: rest -> if contains l head then rest else drop rest
|
|
in
|
|
(* objdump prints a blank line after the last instruction of a symbol and
|
|
then whatever follows it in the section. Stopping at that line is what
|
|
keeps a one-function listing from running into the next function. *)
|
|
let rec upto = function
|
|
| [] -> []
|
|
| l :: rest -> if String.trim l = "" then [] else l :: upto rest
|
|
in
|
|
let body = upto (drop lines) in
|
|
let base = ref None in
|
|
let out = ref [] in
|
|
List.iter
|
|
(fun l ->
|
|
match String.split_on_char '\t' l with
|
|
| addr :: bytes :: rest ->
|
|
let a = String.trim addr in
|
|
let a =
|
|
if String.length a > 0 && a.[String.length a - 1] = ':' then
|
|
String.sub a 0 (String.length a - 1)
|
|
else a
|
|
in
|
|
(match int_of_string_opt ("0x" ^ a) with
|
|
| None -> ()
|
|
| Some n ->
|
|
if !base = None then base := Some n;
|
|
let b = match !base with Some b -> b | None -> n in
|
|
out :=
|
|
{ off = n - b; bytes = String.trim bytes;
|
|
text = String.trim (String.concat "\t" rest) }
|
|
:: !out)
|
|
| _ -> ())
|
|
body;
|
|
(List.rev !out, !base <> None)
|
|
|
|
(* A branch inside the function shows as [<flan.step+0x79>] or, for the entry,
|
|
[<flan.step>]. Those become [L0]..[Ln] in address order, as SBCL labels
|
|
them; anything else objdump annotated — a cell, a plt entry, another
|
|
function — is left exactly as it wrote it. *)
|
|
let target_of ~sym text =
|
|
if not (contains text ("<" ^ sym)) then None
|
|
else
|
|
match String.index_opt text '<' with
|
|
| None -> None
|
|
| Some i ->
|
|
let rest = String.sub text i (String.length text - i) in
|
|
if String.length rest < 3 || rest.[String.length rest - 1] <> '>' then None
|
|
else
|
|
let inner = String.sub rest 1 (String.length rest - 2) in
|
|
if String.equal inner sym then Some 0
|
|
else
|
|
let p = String.length sym in
|
|
if String.length inner > p + 1 && String.sub inner 0 (p + 1) = sym ^ "+"
|
|
then
|
|
int_of_string_opt (String.sub inner (p + 1) (String.length inner - p - 1))
|
|
else None
|
|
|
|
let render_listing ~sym insns =
|
|
let targets =
|
|
List.sort_uniq compare
|
|
(List.filter_map (fun i -> target_of ~sym i.text) insns)
|
|
in
|
|
let label n =
|
|
let rec idx k = function
|
|
| [] -> None
|
|
| x :: r -> if x = n then Some (Printf.sprintf "L%d" k) else idx (k + 1) r
|
|
in
|
|
idx 0 targets
|
|
in
|
|
let b = Buffer.create 4096 in
|
|
List.iter
|
|
(fun i ->
|
|
(match label i.off with
|
|
| Some lb -> Buffer.add_string b (lb ^ ":\n")
|
|
| None -> ());
|
|
let text =
|
|
match target_of ~sym i.text with
|
|
| Some n ->
|
|
(match label n with
|
|
| Some lb ->
|
|
(* [jmp 1d9 <flan.step+0x89>] becomes [jmp L1]. The bare number
|
|
objdump prints is the address the branch encodes *in the
|
|
file*, which is the one number on the line that means nothing
|
|
once the listing is rebased — so it goes with the symbol it
|
|
duplicates. *)
|
|
let j = String.index i.text '<' in
|
|
let head = String.sub i.text 0 j in
|
|
let k = ref (String.length head) in
|
|
while !k > 0 && head.[!k - 1] = ' ' do decr k done;
|
|
while !k > 0
|
|
&& (match head.[!k - 1] with
|
|
| '0' .. '9' | 'a' .. 'f' | 'A' .. 'F' -> true
|
|
| _ -> false)
|
|
do decr k done;
|
|
String.sub head 0 !k ^ lb
|
|
| None -> i.text)
|
|
| None -> i.text
|
|
in
|
|
if text = "" then
|
|
Buffer.add_string b (Printf.sprintf " %04x %s\n" i.off i.bytes)
|
|
else
|
|
Buffer.add_string b
|
|
(Printf.sprintf " %04x %-22s %s\n" i.off i.bytes text))
|
|
insns;
|
|
Buffer.contents b
|
|
|
|
let asm_of ~obj name =
|
|
let sym = "flan." ^ name in
|
|
let code, text =
|
|
run_capture
|
|
(String.concat " "
|
|
[ Filename.quote objdump; "-d";
|
|
"--disassemble=" ^ Filename.quote sym; Filename.quote obj ])
|
|
in
|
|
if code <> 0 then
|
|
Error
|
|
(Printf.sprintf "%s failed on %s (exit %d): %s" objdump obj code
|
|
(String.trim text))
|
|
else
|
|
match parse_listing ~sym text with
|
|
| _, false -> Error (Printf.sprintf "%s found no symbol %s in %s" objdump sym obj)
|
|
| insns, true -> Ok (render_listing ~sym insns)
|
|
|
|
(* Where a name's body was last built, and how much of that is a claim about
|
|
the running process rather than about this daemon's disk. *)
|
|
let basis t name =
|
|
match Hashtbl.find_opt t.owners name with
|
|
| None ->
|
|
( { ogen = 0; oso = t.host_exe; oll = t.host_ll;
|
|
oloc = host_loc t name },
|
|
"the host executable — nothing defining this name has been delivered in \
|
|
this session, so the program's cell still holds this body" )
|
|
| Some o ->
|
|
let m = Filename.basename o.oso in
|
|
( o,
|
|
match state t with
|
|
| Stopped c ->
|
|
(* Not "so it is not installed yet". The commonest way to stop is to
|
|
install a body and have it error, so a stopped program is more
|
|
likely to be running this code than not — the daemon simply cannot
|
|
read the cell back to find out, and saying otherwise would be the
|
|
[ok]-means-probably failure in the one field that exists to prevent
|
|
it. What is certain is only the second half. *)
|
|
Printf.sprintf
|
|
"%s — the last module delivered for this name, accepted for install; \
|
|
the program is stopped on %s and the daemon cannot read the cell \
|
|
back to say whether it installed this before stopping. Nothing \
|
|
further installs until it resumes"
|
|
m c
|
|
| Running ->
|
|
Printf.sprintf
|
|
"%s — the last module delivered for this name, accepted for install; \
|
|
the program installs it at its next frame boundary and the daemon \
|
|
cannot read the cell back to confirm that it has"
|
|
m
|
|
| Unreachable r ->
|
|
Printf.sprintf
|
|
"%s — the last module delivered for this name; the program is not \
|
|
answering (%s), so whether it installed cannot be said"
|
|
m r )
|
|
|
|
let kind_of t name =
|
|
let p = t.session.Session.program in
|
|
if List.exists (fun (g : Tast.global) -> String.equal g.Tast.gname name)
|
|
p.Tast.globals
|
|
then Some "a global"
|
|
else if
|
|
List.exists (fun (e : Tast.extern) -> String.equal e.Tast.ename name)
|
|
p.Tast.externs
|
|
then Some "an extern"
|
|
else None
|
|
|
|
let disassemble t ~name ~form =
|
|
if form <> "ir" && form <> "asm" then
|
|
error
|
|
(Printf.sprintf
|
|
"unknown form %S: disassemble takes :form \"ir\" or :form \"asm\"" form)
|
|
else
|
|
match find_fn t name with
|
|
| None ->
|
|
(match kind_of t name with
|
|
| Some k ->
|
|
error
|
|
(Printf.sprintf
|
|
"%s is %s, not a function: there is no generated code to show for it"
|
|
name k)
|
|
| None -> error (Printf.sprintf "no function named %s in this session" name))
|
|
| Some f ->
|
|
let o, why = basis t name in
|
|
let common =
|
|
[ ":name " ^ Wire.quote name; ":form " ^ Wire.quote form;
|
|
":generation " ^ string_of_int o.ogen;
|
|
":signature " ^ Wire.quote (signature_of_fn f);
|
|
(* [o.oloc], not the session's: the session moves on as soon as a
|
|
form checks, and this has to name the source the code being shown
|
|
was built from. *)
|
|
":loc " ^ Wire.quote o.oloc;
|
|
":basis " ^ Wire.quote why ]
|
|
in
|
|
if form = "ir" then
|
|
match read_file o.oll with
|
|
| text ->
|
|
(match ir_of ~ir:text name with
|
|
| Some body ->
|
|
ok (common @ [ ":object " ^ Wire.quote o.oll; ":text " ^ Wire.quote body ])
|
|
| None ->
|
|
error (Printf.sprintf "no define for %s in %s" (Emit.fname name) o.oll))
|
|
| exception Sys_error m ->
|
|
error ("the IR this body was built from is gone: " ^ m)
|
|
else if not (Sys.file_exists o.oso) then
|
|
error ("the object this body was linked into is gone: " ^ o.oso)
|
|
else
|
|
match asm_of ~obj:o.oso name with
|
|
| Ok text ->
|
|
ok
|
|
(common
|
|
@ [ ":object " ^ Wire.quote o.oso;
|
|
":note "
|
|
^ Wire.quote
|
|
"source interleaving needs line tables this build does not \
|
|
emit";
|
|
":text " ^ Wire.quote text ])
|
|
| Error m -> error m
|
|
|
|
(* ── The watch table ───────────────────────────────────────────────── *)
|
|
|
|
(* Read the table the *program* fills, and arm and disarm it.
|
|
|
|
This op is the opposite shape from every other one here, and the reason is
|
|
worth stating because the obvious design is the wrong one. Everything else
|
|
in this file answers a question by *compiling something*: a locals listing,
|
|
an inspection, a globals section are each a thunk built from the types, sent
|
|
over, and run at a frame boundary. That is affordable at the rate a person
|
|
presses a key and ruinous at the rate a HUD refreshes — an evaluation here
|
|
is a module and a [dlopen], tens of milliseconds and a new .so in a
|
|
directory nothing sweeps, so a 5Hz poll is hundreds of shared objects a
|
|
minute.
|
|
|
|
So the program pushes instead. It calls [flan_dev_watch_*] from inside its
|
|
own loop, which renders the value and stores it under a name; this reads the
|
|
table, which is memory. Nothing is compiled, nothing is loaded, and the
|
|
answer is as cheap as [status].
|
|
|
|
Two things fall out of that which a poll could not have. The values update
|
|
at *frame rate* rather than at whatever the editor's timer is. And they are
|
|
still here while the program is *stopped* — a break loop is exactly when a
|
|
thunk cannot be run at a frame boundary, because there are no more frames,
|
|
and it is exactly when you want to see the last one's values. *)
|
|
|
|
(* On and off are a message rather than something inferred, because the writer
|
|
is the program: the table is untouched while it is off, which is what makes
|
|
a watch call in a program nobody is debugging a load and a not-taken branch.
|
|
See [flan_dev_watch_enable]. *)
|
|
let watch_enable t ~on =
|
|
match String.trim (request t (if on then "watch on" else "watch off")) with
|
|
| "ok" -> ok [ (if on then ":watching t" else ":watching nil") ]
|
|
| reply -> error ("the program refused the watch request: " ^ reply)
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error ("cannot reach the program: " ^ Unix.error_message e)
|
|
|
|
(* [NAME <tab> VALUE] per line, after a header of [COUNT DROPPED].
|
|
|
|
Tab is safe as the separator for [render_locals]'s reason: every string that
|
|
reaches a value goes through an emitter that escapes tab and newline, so
|
|
neither can appear inside one. [OVERFLOW] is carried rather than dropped —
|
|
a name that found no slot is a value that never appears, and a buffer that
|
|
said nothing about it would be lying by omission. It is a flag and not a
|
|
count on purpose: the only number available is of write *attempts* that
|
|
missed, which at frame rate says "3847 names" about one name. *)
|
|
(* [~reset] opens a new accumulation window for the numeric slots, *after* the
|
|
read rather than instead of it. A read that reset as a side effect would
|
|
make looking change what is there, so anything that polls would silently
|
|
shorten the window and come back with a count that means nothing. Two
|
|
messages down a unix socket, one of which is four bytes of reply. *)
|
|
let watch_read t ~reset =
|
|
match request t "watch" with
|
|
| text ->
|
|
let finish result =
|
|
if reset then
|
|
(try ignore (request t "watch reset") with Unix.Unix_error _ -> ());
|
|
result
|
|
in
|
|
let lines = String.split_on_char '\n' text in
|
|
finish
|
|
@@ (match lines with
|
|
| [] -> error "the program gave an empty watch reply"
|
|
| hdr :: rows when not (String.length hdr >= 3 && String.sub hdr 0 3 = "err")
|
|
->
|
|
let overflow =
|
|
match String.split_on_char ' ' (String.trim hdr) with
|
|
| [ _; d ] -> d <> "0"
|
|
| _ -> false
|
|
in
|
|
let pair line =
|
|
match String.index_opt line '\t' with
|
|
| None -> None
|
|
| Some i ->
|
|
Some
|
|
(Wire.list
|
|
[ Wire.quote (String.sub line 0 i);
|
|
Wire.quote
|
|
(String.sub line (i + 1) (String.length line - i - 1)) ])
|
|
in
|
|
ok
|
|
[ ":watch " ^ Wire.list (List.filter_map pair rows);
|
|
(if overflow then ":overflow t" else ":overflow nil") ]
|
|
| hdr :: _ -> error (String.trim hdr))
|
|
| exception Unix.Unix_error (e, _, _) ->
|
|
error ("cannot reach the program: " ^ Unix.error_message e)
|
|
|
|
let handle t req =
|
|
match Wire.string_field req "op" with
|
|
| Some "eval" ->
|
|
(match Wire.string_field req "code" with
|
|
| Some code ->
|
|
let origin =
|
|
match Wire.string_field req "file" with Some f -> f | None -> "<editor>"
|
|
in
|
|
eval t ~code ~origin
|
|
| None -> error "eval needs :code")
|
|
| Some "eval-expr" ->
|
|
(match Wire.string_field req "code" with
|
|
| Some code ->
|
|
let origin =
|
|
match Wire.string_field req "file" with Some f -> f | None -> "<editor>"
|
|
in
|
|
eval_expr t ~code ~origin
|
|
| None -> error "eval-expr needs :code")
|
|
| Some "describe" -> describe t
|
|
| Some "defs" -> defs t
|
|
| Some "break" -> break t
|
|
| Some "backtrace" -> backtrace_op t
|
|
| Some "locals" ->
|
|
locals t ~frame:(match Wire.int_field req "frame" with Some n -> n | None -> 0)
|
|
(* The path is read by the language's own reader, so it arrives as a form
|
|
and is matched here rather than parsed out of a string: a string element
|
|
is a field, an integer is an element, and the symbol [some] is an
|
|
option's payload. Anything else is refused by name rather than skipped —
|
|
a path with a step silently dropped out of it would render a *different*
|
|
value and say nothing. *)
|
|
| Some "inspect" ->
|
|
(match Wire.int_field req "slot" with
|
|
| None -> error "inspect needs :slot, the index the locals listing gave"
|
|
| Some slot ->
|
|
let frame =
|
|
match Wire.int_field req "frame" with Some n -> n | None -> 0
|
|
in
|
|
let steps =
|
|
match Wire.field req "path" with
|
|
| Some { Form.v = Form.List l; _ } ->
|
|
List.fold_left
|
|
(fun acc (e : Form.t) ->
|
|
match acc with
|
|
| Error _ -> acc
|
|
| Ok got ->
|
|
(match e.Form.v with
|
|
| Form.Str f -> Ok (Session.Sfield f :: got)
|
|
| Form.Int i -> Ok (Session.Sindex (Int64.to_int i) :: got)
|
|
| Form.Sym "some" -> Ok (Session.Ssome :: got)
|
|
| _ ->
|
|
Error
|
|
"a :path step is a string for a field, an integer for an element, or `some' for an option's payload"))
|
|
(Ok []) l
|
|
|> Result.map List.rev
|
|
(* Emacs prints an empty list as [nil], because it has no other
|
|
spelling for one. Taking it is cheaper than making every client
|
|
in that language special-case the empty path, and [nil] is not a
|
|
step under any other reading. *)
|
|
| Some { Form.v = Form.Sym "nil"; _ } -> Ok []
|
|
| Some _ -> Error "inspect's :path is a list"
|
|
| None -> Ok []
|
|
in
|
|
(match steps with
|
|
| Error m -> error m
|
|
| Ok path -> inspect t ~frame ~slot ~path))
|
|
(* No :frame, and that is the point: the section is the stack's, not a
|
|
frame's. See [globals_op]. *)
|
|
| Some "globals" -> globals_op t
|
|
| Some "layout" ->
|
|
(match Wire.string_field req "type" with
|
|
| Some ty -> layout t ~ty
|
|
| None -> error "layout needs :type")
|
|
| Some "restart" ->
|
|
(match Wire.string_field req "name" with
|
|
| Some name -> choose t ~name
|
|
| None -> error "restart needs :name")
|
|
(* By index, which is the one that can name a shadowed restart. [:name] is
|
|
optional and is not the lookup: it is checked against the name the program
|
|
has at that index and refused if they have drifted apart, so a client that
|
|
listed and then chose cannot take a different restart than the one it
|
|
showed. *)
|
|
| Some "restart-at" ->
|
|
(match Wire.int_field req "index" with
|
|
| Some index -> choose_at t ~index ~name:(Wire.string_field req "name")
|
|
| None -> error "restart-at needs :index")
|
|
| Some "abort" -> abort t
|
|
(* [:on] is how the buffer says it opened or closed. Without it the table is
|
|
never written, which is the point: a program with watch calls in it and
|
|
nobody looking pays a load and a branch and nothing else. *)
|
|
| Some "watch-enable" ->
|
|
watch_enable t
|
|
~on:(match Wire.field req "on" with
|
|
| Some { Form.v = Form.Sym "nil"; _ } | None -> false
|
|
| Some _ -> true)
|
|
| Some "watch" ->
|
|
(* Same shape as [:on] above: absent or [nil] is false, anything else is
|
|
true. Absent is the important half — a reader that does not ask to reset
|
|
must not, so a second editor or a test polling the table cannot cut the
|
|
window short under the one that does. *)
|
|
watch_read t
|
|
~reset:(match Wire.field req "reset" with
|
|
| Some { Form.v = Form.Sym "nil"; _ } | None -> false
|
|
| Some _ -> true)
|
|
| Some "disassemble" ->
|
|
(match Wire.string_field req "name" with
|
|
| Some name ->
|
|
let form =
|
|
match Wire.string_field req "form" with Some f -> f | None -> "asm"
|
|
in
|
|
disassemble t ~name ~form
|
|
| None -> error "disassemble needs :name")
|
|
| Some "close" -> ok []
|
|
| Some op -> error ("unknown op: " ^ op)
|
|
| None -> error "no :op"
|
|
|
|
(* ── The loop ──────────────────────────────────────────────────────── *)
|
|
|
|
(* One connection at a time. An editor is one client, evaluations are
|
|
sequential by nature — each one is checked against the program the last one
|
|
left behind — and a second concurrent evaluation would be racing for the
|
|
same session anyway. *)
|
|
(* Returns whether the client asked to end the session. One editor per daemon,
|
|
so [close] shuts the whole thing down rather than waiting for another
|
|
connection nobody is going to make. *)
|
|
let serve t fd =
|
|
let rec go () =
|
|
match Wire.recv fd with
|
|
| src ->
|
|
let op, reply =
|
|
match Wire.parse src with
|
|
| req -> (Wire.string_field req "op", handle t req)
|
|
| exception Loc.Error { Loc.dmsg = m; _ } -> (None, error ("bad request: " ^ m))
|
|
in
|
|
Wire.send fd (with_output t (with_break t reply));
|
|
if op = Some "close" then true else go ()
|
|
| exception Wire.Closed -> false
|
|
| exception Unix.Unix_error _ -> false
|
|
in
|
|
go ()
|
|
|
|
(* [accept] would block past the program's own exit, so it is waited on with
|
|
a timeout and the child checked each time round: a daemon whose program has
|
|
finished has nothing left to do, and an editor waiting on it would wait
|
|
forever. In the merged build [alive] is always true and the loop ends the
|
|
only way it can — the process does, taking the program with it. *)
|
|
let accept_loop t ls =
|
|
let rec go () =
|
|
if alive t then
|
|
(* The program's pipe is in the same select as the listening socket: it
|
|
has to be drained whether or not an editor is asking for anything. *)
|
|
match Unix.select [ ls; t.stdout ] [] [] 0.2 with
|
|
| [], _, _ -> go ()
|
|
| ready, _, _ when not (List.mem ls ready) -> drain t; go ()
|
|
| _ ->
|
|
(match Unix.accept ls with
|
|
| fd, _ ->
|
|
let closed = serve t fd in
|
|
(try Unix.close fd with Unix.Unix_error _ -> ());
|
|
if not closed then go ()
|
|
| exception Unix.Unix_error (Unix.EINTR, _, _) -> go ())
|
|
| exception Unix.Unix_error (Unix.EINTR, _, _) -> go ()
|
|
in
|
|
go ()
|
|
|
|
(* [debug] is off by default, which keeps [flan dev] exactly what it was: a
|
|
-O2 host and -O2 modules. It is opt-in rather than always-on because a debug
|
|
build is an -O0 build — [llvm.dbg.declare] describes an alloca and mem2reg
|
|
deletes it — and silently making every reloaded body -O0 would change the
|
|
frame time of the one function you are iterating on, in the loop whose whole
|
|
point is watching that number. *)
|
|
let two_process ?(debug = false) ~file ~sock () =
|
|
let t0 = Unix.gettimeofday () in
|
|
(* Absolute, because every location this daemon ever reports is derived from
|
|
it and an editor is not in this process's working directory. [flan dev
|
|
src/game.flan] run from a project root would otherwise send back
|
|
"src/game.flan:12:7", which the editor can only resolve by guessing which
|
|
directory it was relative to. *)
|
|
let file = try Unix.realpath file with Unix.Unix_error _ -> file in
|
|
let session, l = Session.create ~debug ~file () in
|
|
let dir =
|
|
Filename.concat (Filename.get_temp_dir_name ())
|
|
(Printf.sprintf "flan-dev-%d" (Unix.getpid ()))
|
|
in
|
|
(try Unix.mkdir dir 0o700 with Unix.Unix_error (Unix.EEXIST, _, _) -> ());
|
|
let exe = Filename.concat dir "program" in
|
|
(* [keep] so the host's own IR survives the build. It is the text [llc] was
|
|
actually given, not a second emission of it, which is the difference
|
|
between showing what the process was built from and showing what it
|
|
probably was. [Build.executable] leaves it in its own working directory
|
|
under the module's basename; it is moved here so that nothing else in this
|
|
process can reuse the name. *)
|
|
(* The host and the modules are one decision. DWARF in a redefinition is
|
|
only half a debuggable dev loop: lldb re-resolves a *name* breakpoint
|
|
against each module as it loads either way, but a breakpoint set on a line
|
|
in the .flan buffer needs a line table on both sides — the host's to fire
|
|
before the first C-c C-c, the module's to follow the reload. *)
|
|
ignore
|
|
(Build.executable
|
|
~opts:{ Build.default with Build.dev = true; Build.keep = true;
|
|
Build.debug }
|
|
~csrcs:l.Load.csrcs ~lflags:l.Load.lflags session.Session.host ~out:exe);
|
|
let host_ll = Filename.concat dir "host.ll" in
|
|
(try
|
|
Sys.rename (Filename.concat (Build.workdir ()) (Filename.basename exe ^ ".ll"))
|
|
host_ll
|
|
with Sys_error _ -> ());
|
|
let agent = Filename.concat dir "agent.sock" in
|
|
|
|
(* The program's source names some socket path; the daemon is the one that
|
|
knows where it wants to talk to it, so it overrides through the
|
|
environment. Guessing instead would fail silently — everything compiles,
|
|
the module is built, and nothing ever receives it. *)
|
|
Unix.putenv "FLAN_AGENT_SOCKET" agent;
|
|
(* Through a pipe, so the program's own output can reach an editor instead of
|
|
only the terminal the daemon was started in. *)
|
|
let rd, wr = Unix.pipe ~cloexec:false () in
|
|
let child = Unix.create_process exe [| exe |] Unix.stdin wr Unix.stderr in
|
|
Unix.close wr;
|
|
Unix.set_nonblock rd;
|
|
|
|
(* Wait for it to bind before accepting an evaluation. One that arrives first
|
|
would fail for a reason that reads like a compiler bug. *)
|
|
if not (await (fun () -> Sys.file_exists agent)) then begin
|
|
(try Unix.kill child Sys.sigterm with Unix.Unix_error _ -> ());
|
|
failwith
|
|
("the program never listened on " ^ agent
|
|
^ " — does it call (agent/start ...)?")
|
|
end;
|
|
|
|
let t =
|
|
{ session; child = Some child; agent; dir; stdout = rd;
|
|
out = Buffer.create 4096; n = 0; gen = 0; owners = Hashtbl.create 32;
|
|
host_ll; host_exe = exe; finished = false }
|
|
in
|
|
(try Unix.unlink sock with Unix.Unix_error _ -> ());
|
|
let ls = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
|
|
Unix.bind ls (Unix.ADDR_UNIX sock);
|
|
Unix.listen ls 4;
|
|
Printf.eprintf "flan dev: %s ready on %s (%.0fms)\n%!" file sock
|
|
((Unix.gettimeofday () -. t0) *. 1000.);
|
|
Fun.protect
|
|
~finally:(fun () ->
|
|
(try Unix.kill child Sys.sigterm with Unix.Unix_error _ -> ());
|
|
(try Unix.close ls with Unix.Unix_error _ -> ());
|
|
(try Unix.close rd with Unix.Unix_error _ -> ());
|
|
(try Unix.unlink sock with Unix.Unix_error _ -> ()))
|
|
(fun () -> accept_loop t ls)
|
|
|
|
(* ── One process: the program and the compiler in the same binary ──── *)
|
|
|
|
(* Everything above this line works the same either way. What follows is the
|
|
merged build: one executable that is the compiled Flan program *and* holds
|
|
the whole OCaml compiler, with the editor's socket served from a thread
|
|
inside it. DISCUSS.md item 14 is the spike this is built from.
|
|
|
|
The shape, and it is this way round for a reason:
|
|
|
|
main() C, the game's thread. Runs the Flan program.
|
|
+ a pthread caml_startup, then [merged_setup] and
|
|
[merged_serve] — the compiler and the
|
|
editor's listener.
|
|
+ a pthread flan_agent.c's accept loop, as today.
|
|
|
|
The game keeps main() because on macOS a window has to be on the main
|
|
thread. The compiler goes to the side, beside the listener that was already
|
|
there. Nothing about that is Linux-specific.
|
|
|
|
TWO RULES, and neither is a style preference. Both are the reason this is
|
|
safe at all, and both are silently broken by one convenient shortcut.
|
|
|
|
1. THE GAME THREAD MUST NEVER CALL INTO OCAML. OCaml's collector stops
|
|
OCaml threads at safe points. A pure native thread has none, so it cannot
|
|
be stopped — which is exactly why the GC will never pause a frame. That
|
|
holds only while the game thread is not inside an OCaml call: one direct
|
|
call from the frame loop and a major collection can land in the middle of
|
|
it. Requests reach the compiler by being *left somewhere and picked up*,
|
|
never by a call. The agent already works this way — a socket, a ring and
|
|
two atomics — and it stays that way. If a future handler wants something
|
|
from the game thread, it leaves a request and waits; it does not call.
|
|
|
|
2. NEVER STORE AN OCAML [value] IN FLAN STORAGE. Not in an arena, not in a
|
|
[Vec], not in a global, not across an allocation. The collector moves its
|
|
own blocks and will not update a word it does not know is a root;
|
|
[caml_register_global_root] (or the generational one) is the only legal
|
|
way. The boundary passes pointers and scalars. This is the chief way the
|
|
"the GC does not touch Flan's memory" measurement stops being true, and
|
|
it would fail intermittently rather than loudly.
|
|
|
|
WHERE REPL-FIRST WOULD DIFFER, noted now because it is much cheaper to leave
|
|
room for than to retrofit. Today [main] runs the program and the compiler
|
|
comes up beside it. The SBCL arrangement is the same binary with the two
|
|
swapped: the C [main] would not call [flan_program_main] at all, it would
|
|
park, and opening the window would be something typed at the prompt — one
|
|
more op that asks the game thread to run a named function. The startup below
|
|
is the only place that decides, and it decides in three lines of C. What is
|
|
genuinely open is the *session*: [Session.create ~file] is the only entry
|
|
there is, so a REPL that starts empty and accumulates as files are loaded
|
|
needs [Session] to have a second constructor. It already accumulates; it
|
|
just cannot start from nothing. *)
|
|
|
|
let ocamlfind = try Sys.getenv "FLAN_OCAMLFIND" with Not_found -> "ocamlfind"
|
|
|
|
(* The C that owns the process. A string here rather than a file under
|
|
[runtime/] for the reason [Build.wasm_main_source] is one: the compiler
|
|
carries the C it needs instead of looking for it on disk, and only the two
|
|
files [lib/dune] already embeds are reachable that way. *)
|
|
let merged_main_source = {c|
|
|
/* Generated by flan dev. The merged build's entry point: the Flan program owns
|
|
* the main thread, the OCaml compiler comes up on a thread beside it.
|
|
*
|
|
* See lib/dev.ml for the two rules this arrangement depends on. The short
|
|
* form: this thread — the one running flan_program_main — must never enter
|
|
* OCaml, and no OCaml value may be stored in Flan memory. */
|
|
#include <caml/callback.h>
|
|
#include <caml/mlvalues.h>
|
|
#include <pthread.h>
|
|
#include <fcntl.h>
|
|
#include <stdatomic.h>
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
/* The Flan program's entry point. Emit writes it as @main; flan dev renames it
|
|
* in the IR so that this file can own main() instead. */
|
|
extern int flan_program_main(int argc, char **argv);
|
|
|
|
/* flan_rt.c's, and the reason the program's exit does not end the session. */
|
|
extern void (*flan_exit_hook)(int32_t status);
|
|
|
|
/* Installed on flan_rt.c's hook, which a Flan main reaches instead of
|
|
* returning: Emit ends @main with a call to flan_exit and an unreachable.
|
|
*
|
|
* In one process that call cannot be allowed to end the process — it would
|
|
* take the compiler, the editor's socket and the session down with a program
|
|
* that merely finished. So it flushes, closes stdout so that the compiler
|
|
* learns the program is done exactly as the daemon learned it (the pipe reads
|
|
* EOF, which is what the child's death used to cause), and parks.
|
|
*
|
|
* Parking rather than exiting is also the REPL-first shape in miniature: the
|
|
* process outliving the program is the whole of the difference between "run a
|
|
* program with a REPL attached" and "an image you run programs in". */
|
|
static void flan_merged_exit(int32_t status) {
|
|
(void)status;
|
|
fflush(NULL);
|
|
close(1);
|
|
/* ...and take fd 1 straight back, because POSIX hands out the lowest free
|
|
* descriptor: leave it open and the compiler thread's next socket or file
|
|
* becomes this process's stdout, and the next llc inherits it. The EOF is
|
|
* unaffected — the pipe's write end is genuinely gone. */
|
|
if (open("/dev/null", O_WRONLY) < 0) { /* nothing useful to do about it */ }
|
|
for (;;) pause();
|
|
}
|
|
|
|
static char **g_argv;
|
|
/* Atomic, not a plain int: this is the only happens-before edge between the
|
|
* two threads, and everything the compiler set up before it — the listening
|
|
* socket, the redirected stdout — has to be visible to the program after it. */
|
|
static atomic_int compiler_ready = 0;
|
|
|
|
static void flan_merged_nap(long ms) {
|
|
struct timespec t;
|
|
t.tv_sec = ms / 1000;
|
|
t.tv_nsec = (ms % 1000) * 1000000L;
|
|
nanosleep(&t, NULL);
|
|
}
|
|
|
|
static const value *flan_merged_need(const char *n) {
|
|
const value *f = caml_named_value(n);
|
|
if (!f) {
|
|
fprintf(stderr, "flan dev: %s is not registered in this binary\n", n);
|
|
fflush(NULL);
|
|
_exit(70);
|
|
}
|
|
return f;
|
|
}
|
|
|
|
static void *flan_merged_compiler(void *unused) {
|
|
(void)unused;
|
|
caml_startup(g_argv);
|
|
/* Two callbacks and not one: setup has to have finished — the socket bound,
|
|
* stdout redirected — before the program starts, and serve never returns. */
|
|
caml_callback(*flan_merged_need("flan_merged_setup"), Val_unit);
|
|
atomic_store(&compiler_ready, 1);
|
|
caml_callback(*flan_merged_need("flan_merged_serve"), Val_unit);
|
|
fflush(NULL);
|
|
_exit(0);
|
|
}
|
|
|
|
int main(int argc, char **argv) {
|
|
pthread_t compiler;
|
|
int rc;
|
|
g_argv = argv;
|
|
flan_exit_hook = flan_merged_exit;
|
|
if (pthread_create(&compiler, NULL, flan_merged_compiler, NULL) != 0) {
|
|
fprintf(stderr, "flan dev: could not start the compiler thread\n");
|
|
return 1;
|
|
}
|
|
while (!atomic_load(&compiler_ready)) flan_merged_nap(1);
|
|
|
|
/* From here the main thread is the program's and nothing else's. It does not
|
|
* enter OCaml, and it is not joined with the compiler thread — that thread
|
|
* is in an accept loop it never leaves. */
|
|
/* Does not come back: a Flan main ends in flan_exit, which is hooked above.
|
|
* The lines below are for a program that somehow does return. */
|
|
rc = flan_program_main(argc, argv);
|
|
|
|
/* _exit, not exit, for the reason the break loop gives: the atexit chain and
|
|
* the ELF destructors want the loader lock the agent's listener may be
|
|
* holding inside dlopen, and the merged build adds OCaml's own shutdown to
|
|
* that chain. The streams are flushed by hand instead.
|
|
*
|
|
* This is also the line REPL-first would delete: park here instead, and the
|
|
* window becomes something the prompt asks for rather than the thing the
|
|
* process is. */
|
|
fprintf(stderr,
|
|
"flan dev: the program returned %d; the session ends with it\n", rc);
|
|
fflush(NULL);
|
|
_exit(rc);
|
|
}
|
|
|c}
|
|
|
|
(* The OCaml half's roots. [-output-complete-obj] links a .cmxa the way an
|
|
executable does — only the modules something refers to — so this file is
|
|
what pulls [Flan.Dev] and everything under it into the object. *)
|
|
let merged_entry_source =
|
|
"let () =\n\
|
|
\ Callback.register \"flan_merged_setup\" Flan.Dev.merged_setup;\n\
|
|
\ Callback.register \"flan_merged_serve\" Flan.Dev.merged_serve\n"
|
|
|
|
(* Where [flan.cmxa] is, which is the one thing the merged build needs that a
|
|
normal build does not. The compiler finds its own library beside itself;
|
|
[FLAN_LIBDIR] overrides for an install layout that does not match. *)
|
|
let libdir () =
|
|
let exe =
|
|
try Unix.realpath Sys.executable_name
|
|
with Unix.Unix_error _ -> Sys.executable_name
|
|
in
|
|
let bin = Filename.dirname exe in
|
|
let candidates =
|
|
(match Sys.getenv_opt "FLAN_LIBDIR" with Some d -> [ d ] | None -> [])
|
|
@ [ Filename.concat (Filename.dirname bin) "lib" ]
|
|
in
|
|
List.find_opt
|
|
(fun d -> Sys.file_exists (Filename.concat d "flan.cmxa"))
|
|
candidates
|
|
|
|
(* The whole compiler as one object file, cached. Keyed on a digest of
|
|
[flan.cmxa] and [flan.a] rather than on their existence: without that, an
|
|
edit to this very file rebuilds the library and the merged binary goes on
|
|
running the previous one — which costs an hour of chasing a ghost. *)
|
|
let compiler_object () =
|
|
match libdir () with
|
|
| None ->
|
|
failwith
|
|
"cannot find flan.cmxa beside this binary, so the compiler cannot be \
|
|
linked into the program. Set FLAN_LIBDIR, or run flan dev \
|
|
--two-process."
|
|
| Some lib ->
|
|
let cmxa = Filename.concat lib "flan.cmxa" in
|
|
let arch = Filename.concat lib "flan.a" in
|
|
let dg f = try Digest.to_hex (Digest.file f) with Sys_error _ -> "-" in
|
|
let key =
|
|
Digest.to_hex
|
|
(Digest.string
|
|
(String.concat "\000"
|
|
[ "flan-merged-compiler-1"; dg cmxa; dg arch;
|
|
Build.stamp_of ocamlfind; merged_entry_source ]))
|
|
in
|
|
let obj = Filename.concat (Build.cachedir ()) ("compiler-" ^ key ^ ".o") in
|
|
if not (Sys.file_exists obj) then begin
|
|
let dir = Build.workdir () in
|
|
let ml = Filename.concat dir "flan_merged_entry.ml" in
|
|
Build.write ml merged_entry_source;
|
|
let tmp =
|
|
Printf.sprintf "%s.%d.o" (Filename.remove_extension obj)
|
|
(Unix.getpid ())
|
|
in
|
|
(* [-output-complete-obj], not [-output-obj]: it bundles the runtime, so
|
|
there is no libasmrun to hunt for. The two [-I]s are dune's own object
|
|
directories — the .cmi and the .cmx of the library the entry module
|
|
refers to. *)
|
|
let cmd =
|
|
String.concat " "
|
|
[ Filename.quote ocamlfind; "ocamlopt"; "-thread";
|
|
"-package"; "unix,threads.posix"; "-linkpkg";
|
|
"-output-complete-obj";
|
|
"-I"; Filename.quote (Filename.concat lib ".flan.objs/byte");
|
|
"-I"; Filename.quote (Filename.concat lib ".flan.objs/native");
|
|
(* [lib] again, as a library search path. The macro work gave
|
|
[lib/dune] a [foreign_stubs] stanza, so [flan.cmxa] now records
|
|
a dependency on [-lflan_stubs] and the linker has to be told
|
|
where dune put the archive. Without this the merged object
|
|
fails with "cannot find -lflan_stubs" and only
|
|
[--two-process] works. *)
|
|
"-cclib"; Filename.quote ("-L" ^ lib);
|
|
"-o"; Filename.quote tmp;
|
|
Filename.quote cmxa; Filename.quote ml ]
|
|
in
|
|
let code = Sys.command cmd in
|
|
if code <> 0 then
|
|
failwith
|
|
(Printf.sprintf
|
|
"%s could not build the compiler object (exit %d); flan dev \
|
|
--two-process still works" ocamlfind code);
|
|
(try Unix.rename tmp obj with Unix.Unix_error _ -> ())
|
|
end;
|
|
obj
|
|
|
|
let ocaml_where =
|
|
lazy
|
|
(match run_capture "ocamlopt -where" with
|
|
| 0, s -> String.trim s
|
|
| _ -> "")
|
|
|
|
(* [@main] renamed out of the way, so the C above can own the process. On the
|
|
emitted text rather than in [Emit], because [lib/emit.ml] belongs to another
|
|
lane — and because the spike proved the rename is all it takes. *)
|
|
let rename_program_main ir =
|
|
let needle = "define i32 @main(" in
|
|
let n = String.length needle and len = String.length ir in
|
|
let rec find i =
|
|
if i + n > len then None
|
|
else if String.sub ir i n = needle then Some i
|
|
else find (i + 1)
|
|
in
|
|
match find 0 with
|
|
| None ->
|
|
failwith
|
|
"no @main in the emitted IR — the merged build renames it so a C main \
|
|
can own the process"
|
|
| Some i ->
|
|
String.sub ir 0 i ^ "define i32 @flan_program_main("
|
|
^ String.sub ir (i + n) (len - i - n)
|
|
|
|
(* The link, which is [Build.executable]'s with three additions: the program's
|
|
[@main] renamed, the C above, and the compiler object.
|
|
|
|
It is spelled here rather than as a mode of [Build.executable] because
|
|
[lib/build.ml] belongs to another lane this week. The duplication is real
|
|
and should collapse into [Build] once that lane lands — every piece it uses
|
|
([compile_c], [cflags], [target_flags], [select_csrcs], [select_lflags]) is
|
|
already [Build]'s and already public. Native only: a wasm target has no
|
|
dlopen, no OCaml runtime and no use for any of this. *)
|
|
let merged_executable ~opts ~csrcs ~lflags ~pnames (p : Tast.program) ~out ~ll =
|
|
let open Build in
|
|
(* [Build.executable] forces this and the disassembly machinery believes it:
|
|
a --debug build that came out -O2 makes [basis] and the listing lie. *)
|
|
let opts = if opts.debug then { opts with opt = "-O0" } else opts in
|
|
let tflags = target_flags opts in
|
|
let ir =
|
|
Emit.program ~checks:opts.checks ~dev:opts.dev ~debug:opts.debug ~pnames
|
|
~sanitize:opts.sanitize p
|
|
in
|
|
write ll (rename_program_main ir);
|
|
let cc src name = compile_c ~opts ~tflags ~src ~name () in
|
|
let objs =
|
|
(cc Runtime_src.source "flan_rt.c"
|
|
:: [ cc Runtime_src.dev_source "flan_dev.c" ])
|
|
@ (match p.Tast.cshim with
|
|
| [] -> []
|
|
| parts ->
|
|
[ cc (String.concat "" (List.map snd parts)) "flan_shim.c" ])
|
|
@ List.map (fun c -> cc (read_file c) (Filename.basename c))
|
|
(select_csrcs opts csrcs)
|
|
(* The caml/ headers, so the entry point can call caml_startup. They ride
|
|
in on [tflags], which is part of the object cache key — an entry point
|
|
compiled against one OCaml must not be served to another. *)
|
|
@ [ compile_c ~opts
|
|
~tflags:(tflags @ [ "-I"; Filename.quote (Lazy.force ocaml_where) ])
|
|
~src:merged_main_source ~name:"flan_merged_main.c" () ]
|
|
in
|
|
let cmd =
|
|
String.concat " "
|
|
([ Filename.quote clang; opts.opt; "-Wno-override-module" ]
|
|
@ cflags opts
|
|
(* Still needed, and for the same reason: a delivered module reaches the
|
|
host's cells and globals through the dynamic symbol table. *)
|
|
@ (if opts.dev then [ "-rdynamic" ] else [])
|
|
@ tflags
|
|
@ [ Filename.quote ll ]
|
|
@ List.map Filename.quote objs
|
|
@ [ Filename.quote (compiler_object ()) ]
|
|
@ select_lflags opts lflags
|
|
(* -lzstd is OCaml 5's, not this project's: 5.x's marshaller is
|
|
compressed, and the missing ZSTD_* symbols are the first thing a
|
|
naive link of the runtime fails on. *)
|
|
@ [ "-lm"; "-lpthread"; "-ldl"; "-lzstd" ]
|
|
@ [ "-o"; Filename.quote out ])
|
|
in
|
|
let code = Sys.command cmd in
|
|
if code <> 0 then
|
|
failwith
|
|
(Printf.sprintf
|
|
"%s failed (exit %d) linking the merged build; the IR is at %s" clang
|
|
code ll);
|
|
out
|
|
|
|
(* ── The merged process's own two entry points ─────────────────────── *)
|
|
|
|
(* Held between [merged_setup] and [merged_serve], which are two calls because
|
|
the program must not start until the first has finished and the second never
|
|
returns. *)
|
|
let merged_state = ref None
|
|
|
|
let need_env k =
|
|
match Sys.getenv_opt k with
|
|
| Some v when v <> "" -> v
|
|
| _ ->
|
|
failwith
|
|
(k ^ " is not set: this binary is a [flan dev] build and is started by it")
|
|
|
|
(* Called from the compiler thread, once, before the program runs. *)
|
|
let merged_setup () =
|
|
try
|
|
let t0 = Unix.gettimeofday () in
|
|
let file = need_env "FLAN_DEV_SOURCE" in
|
|
let sock = need_env "FLAN_DEV_SOCK" in
|
|
let dir = need_env "FLAN_DEV_DIR" in
|
|
let host_ll = need_env "FLAN_DEV_HOST_LL" in
|
|
let agent = need_env "FLAN_AGENT_SOCKET" in
|
|
let debug = Sys.getenv_opt "FLAN_DEV_DEBUG" = Some "1" in
|
|
(* The session is built a second time here rather than carried across the
|
|
exec. It is the frontend only — about 12ms — and the alternative is
|
|
marshalling a [Session.t] through a file, which buys nothing: the source
|
|
cannot have changed between the two, because the build that produced
|
|
this binary is the one that exec'd it. *)
|
|
let session, _ = Session.create ~debug ~file () in
|
|
(* The program's output has to reach an editor exactly as it did when the
|
|
daemon held the other end of a pipe. Same pipe, one process: fd 1 is
|
|
replaced before the program starts, and the accept loop drains it —
|
|
which is a liveness requirement and not a nicety, since a pipe nobody
|
|
reads fills at 64K and the next print blocks the game thread for ever. *)
|
|
flush Stdlib.stdout;
|
|
let rd, wr = Unix.pipe ~cloexec:false () in
|
|
Unix.dup2 wr Unix.stdout;
|
|
Unix.close wr;
|
|
Unix.set_nonblock rd;
|
|
let exe =
|
|
try Unix.realpath Sys.executable_name
|
|
with Unix.Unix_error _ -> Sys.executable_name
|
|
in
|
|
let t =
|
|
{ session; child = None; agent; dir; stdout = rd;
|
|
out = Buffer.create 4096; n = 0; gen = 0; owners = Hashtbl.create 32;
|
|
host_ll; host_exe = exe; finished = false }
|
|
in
|
|
(try Unix.unlink sock with Unix.Unix_error _ -> ());
|
|
let ls = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
|
|
Unix.bind ls (Unix.ADDR_UNIX sock);
|
|
Unix.listen ls 4;
|
|
merged_state := Some (t, ls, sock);
|
|
Printf.eprintf "flan dev: %s ready on %s (%.0fms, one process)\n%!" file
|
|
sock ((Unix.gettimeofday () -. t0) *. 1000.)
|
|
with e ->
|
|
Printf.eprintf "flan dev: %s\n%!"
|
|
(match e with Failure m -> m | e -> Printexc.to_string e);
|
|
exit 1
|
|
|
|
(* Called from the compiler thread after the program has started. Never
|
|
returns: the process ends here or not at all. *)
|
|
let merged_serve () =
|
|
match !merged_state with
|
|
| None -> prerr_endline "flan dev: serve was called before setup"; exit 1
|
|
| Some (t, ls, sock) ->
|
|
(* The agent is bound by the program on the main thread, which only starts
|
|
once [merged_setup] has returned — so unlike the daemon, this waits
|
|
*after* it is already serving. An editor connecting in the meantime is
|
|
answered; only a delivery needs the agent. A program that never calls
|
|
[agent/start] is a warning rather than a failure now, because the thing
|
|
the daemon would have killed for it is this process. *)
|
|
if not (await ~ms:10000 (fun () -> Sys.file_exists t.agent)) then
|
|
Printf.eprintf
|
|
"flan dev: the program is not listening on %s — does it call \
|
|
(agent/start ...)?\n%!" t.agent;
|
|
(match accept_loop t ls with
|
|
| () -> ()
|
|
| exception e ->
|
|
Printf.eprintf "flan dev: %s\n%!" (Printexc.to_string e));
|
|
(try Unix.close ls with Unix.Unix_error _ -> ());
|
|
(try Unix.unlink sock with Unix.Unix_error _ -> ());
|
|
(* [close] from the editor ends the session, and in one process that means
|
|
the program too — which is what the daemon did by killing its child.
|
|
[_exit] for the loader-lock reason the break loop gives. *)
|
|
flush_all ();
|
|
Unix._exit 0
|
|
|
|
(* ── Starting a session ────────────────────────────────────────────── *)
|
|
|
|
(* The merged build is made here and then [exec]'d, so what an editor talks to
|
|
is the program itself rather than something that launched it. The launcher
|
|
does not survive: there is one process from the first reply onwards. *)
|
|
let start_merged ?(debug = false) ~file ~sock () =
|
|
let t0 = Unix.gettimeofday () in
|
|
let file = try Unix.realpath file with Unix.Unix_error _ -> file in
|
|
let session, l = Session.create ~debug ~file () in
|
|
let dir =
|
|
Filename.concat (Filename.get_temp_dir_name ())
|
|
(Printf.sprintf "flan-dev-%d" (Unix.getpid ()))
|
|
in
|
|
(try Unix.mkdir dir 0o700 with Unix.Unix_error (Unix.EEXIST, _, _) -> ());
|
|
let exe = Filename.concat dir "program" in
|
|
(* The host's IR goes straight to its final home rather than being written
|
|
into the build's working directory and moved: the merged link is spelled
|
|
in this file, so it can simply be told where to put it. It is the text
|
|
clang was given, with [@main] renamed — which is what this binary really
|
|
was built from, and what [basis] must not misreport. *)
|
|
let host_ll = Filename.concat dir "host.ll" in
|
|
ignore
|
|
(merged_executable
|
|
~opts:{ Build.default with Build.dev = true; Build.debug }
|
|
~csrcs:l.Load.csrcs ~lflags:l.Load.lflags ~pnames:[]
|
|
session.Session.host ~out:exe ~ll:host_ll);
|
|
let agent = Filename.concat dir "agent.sock" in
|
|
(* Every one of these is read by the exec'd binary and by nothing else. They
|
|
are set before the exec rather than by the compiler thread afterwards, so
|
|
that the game thread's [getenv] cannot race the compiler thread's
|
|
[putenv]: there is no ordering left to get wrong. *)
|
|
Unix.putenv "FLAN_AGENT_SOCKET" agent;
|
|
Unix.putenv "FLAN_DEV_SOURCE" file;
|
|
Unix.putenv "FLAN_DEV_SOCK" sock;
|
|
Unix.putenv "FLAN_DEV_DIR" dir;
|
|
Unix.putenv "FLAN_DEV_HOST_LL" host_ll;
|
|
Unix.putenv "FLAN_DEV_DEBUG" (if debug then "1" else "0");
|
|
(try Unix.unlink sock with Unix.Unix_error _ -> ());
|
|
Printf.eprintf "flan dev: built %s in %.0fms\n%!" (Filename.basename file)
|
|
((Unix.gettimeofday () -. t0) *. 1000.);
|
|
Unix.execv exe [| exe |]
|
|
|
|
(* [two_process] is still here and still works. It is the escape hatch for a
|
|
machine where the compiler object cannot be built — no ocamlfind, no
|
|
flan.cmxa beside the binary — and it is what every behaviour in this file
|
|
was written against, so it stays until the transport it exists to drive is
|
|
actually deleted. *)
|
|
let start ?(debug = false) ?(merged = true) ~file ~sock () =
|
|
if merged then start_merged ~debug ~file ~sock ()
|
|
else two_process ~debug ~file ~sock ()
|