File: build_cstubs.ml

package info (click to toggle)
ocaml-obuild 0.2.2-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 1,456 kB
  • sloc: ml: 14,491; sh: 211; ansic: 34; makefile: 11
file content (526 lines) | stat: -rw-r--r-- 24,972 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
open Fugue
open Filepath
open Types
open Helper
open Printf
open Analyze
open Target
open Prepare
open Gconf
open Buildprogs

(* Helper: get include paths for ctypes from dependencies *)
let get_ctypes_includes bstate =
  let stdlib = fp (Analyze.get_ocaml_config_key "standard_library" bstate.bstate_config) in
  (* Find ctypes package paths *)
  try
    (* Get integers library path *)
    let (integers_path, integers_pkg) = Metacache.get "integers" in
    let integers_dir = Meta.get_include_dir stdlib (integers_path, integers_pkg) in

    (* Get str library path *)
    let (str_path, str_pkg) = Metacache.get "str" in
    let str_dir = Meta.get_include_dir stdlib (str_path, str_pkg) in

    let (path, pkg) = Metacache.get "ctypes" in
    let ctypes_dir = Meta.get_include_dir stdlib (path, pkg) in
    let ctypes_stubs_lib = Libname.of_string "ctypes.stubs" in
    let (stubs_path, stubs_root_pkg) = Metacache.get "ctypes" in
    let stubs_pkg = Meta.Pkg.find ctypes_stubs_lib.Libname.subnames stubs_root_pkg in
    let stubs_dir = Meta.get_include_dir stdlib (stubs_path, stubs_pkg) in
    [integers_dir; str_dir; ctypes_dir; stubs_dir]
  with Not_found | Meta.SubpackageNotFound _ | Dependencies.DependencyMissing _ -> []

(* Helper: get ctypes library files for linking *)
let get_ctypes_libs bstate =
  let stdlib = fp (Analyze.get_ocaml_config_key "standard_library" bstate.bstate_config) in
  try
    (* Get integers library (required by ctypes) *)
    let (integers_path, integers_pkg) = Metacache.get "integers" in
    let integers_dir = Meta.get_include_dir stdlib (integers_path, integers_pkg) in
    let integers_cma = integers_dir </> fn "integers.cma" in

    (* Get str library (required by ctypes.stubs) *)
    let (str_path, str_pkg) = Metacache.get "str" in
    let str_dir = Meta.get_include_dir stdlib (str_path, str_pkg) in
    let str_cma = str_dir </> fn "str.cma" in

    (* Get ctypes library *)
    let (path, pkg) = Metacache.get "ctypes" in
    let ctypes_dir = Meta.get_include_dir stdlib (path, pkg) in
    let ctypes_cma = ctypes_dir </> fn "ctypes.cma" in

    (* Get ctypes.stubs library *)
    let ctypes_stubs_lib = Libname.of_string "ctypes.stubs" in
    let (stubs_path, stubs_root_pkg) = Metacache.get "ctypes" in
    let stubs_pkg = Meta.Pkg.find ctypes_stubs_lib.Libname.subnames stubs_root_pkg in
    let stubs_dir = Meta.get_include_dir stdlib (stubs_path, stubs_pkg) in
    let stubs_cma = stubs_dir </> fn "ctypes_stubs.cma" in

    [integers_cma; str_cma; ctypes_cma; stubs_cma]
  with Not_found | Meta.SubpackageNotFound _ | Dependencies.DependencyMissing _ -> []

let get_nb_step dag =
  let nb_step = Dag.length dag in
  let nb_step_len = String.length (string_of_int nb_step) in
  (nb_step, nb_step_len)

(* Generate ctypes.cstubs type discovery - produces types_generated.ml *)
let generate_cstubs_types task_index task lib bstate task_context dag =
  let (cstate, target) = Hashtbl.find task_context task in
  let (nb_step, nb_step_len) = get_nb_step dag in
  log Report "[%*d of %d] Generating cstubs types for %s\n%!" nb_step_len task_index nb_step
    (Libname.to_string lib);
  match target.target_cstubs with
  | None ->
    log Report "  No cstubs configuration found\n%!";
    Scheduler.FinishTask task
  | Some cstubs ->
    let autogen_dir = Dist.get_build_exn Dist.Autogen </> fn (Libname.to_string lib) in
    Filesystem.mkdir_safe autogen_dir 0o755;
    let generated_types_name = cstubs.cstubs_generated_types in
    (* Write generated files to autogen directory - no placeholders needed *)
    let target_file = autogen_dir </> fn (Compat.string_uncapitalize generated_types_name ^ ".ml") in

    (* Check if we have type description *)
    match cstubs.cstubs_type_description with
    | None ->
      (* No type description - generate empty types module *)
      let content = Printf.sprintf
        "(* Auto-generated type bindings for %s *)\n\
         (* No type description specified *)\n"
        (Libname.to_string lib)
      in
      Filesystem.write_file target_file content;
      log Report "  Generated %s (no types)\n%!" (fp_to_string target_file);
      Scheduler.FinishTask task
    | Some type_desc ->
      (* Get the bindings module name *)
      let bindings_hier = type_desc.Target.cstubs_functor in
      let bindings_parts = Hier.to_string bindings_hier in
      (* Split "Bindings.Types" into module "Bindings" and functor "Types" *)
      let parts = String_utils.split '.' bindings_parts in
      let (bindings_module, types_functor) = match parts with
        | [m; f] -> (m, f)
        | [m] -> (m, "Types")
        | m :: _ -> (m, "Types")
        | [] -> (bindings_parts, "Types")
      in

      (* Get paths *)
      let ctypes_includes = get_ctypes_includes bstate in
      let build_dir = cstate.compilation_builddir_ml Normal in
      let src_dirs = target.target_obits.target_srcdir in

      (* Generate discover.ml that uses Cstubs_structs.write_c to discover type layouts.
         This properly handles structs defined in the user's Types functor. *)
      let discover_ml = autogen_dir </> fn "discover.ml" in
      let headers_str = String.concat "; "
        (List.map (fun h -> Printf.sprintf "\"#include <%s>\\n\"" h) cstubs.cstubs_headers) in
      let headers_list = if headers_str = "" then "[]" else Printf.sprintf "[%s]" headers_str in
      let discover_content = Printf.sprintf
        "(* Auto-generated type discovery for %s using Cstubs_structs *)\n\
         let () =\n\
        \  let headers = String.concat \"\" %s in\n\
        \  let fmt = Format.std_formatter in\n\
        \  Format.fprintf fmt \"#include <stddef.h>@.\";\n\
        \  Format.fprintf fmt \"#include <stdint.h>@.\";\n\
        \  Format.fprintf fmt \"%%s\" headers;\n\
        \  Cstubs_structs.write_c fmt (module %s.%s)\n"
        (Libname.to_string lib)
        headers_list
        bindings_module
        types_functor
      in
      Filesystem.write_file discover_ml discover_content;
      log Report "  Generated %s\n%!" (fp_to_string discover_ml);

      (* Compile discover.ml - needs ctypes.stubs and the bindings module *)
      let discover_exe = autogen_dir </> fn "discover.byte" in
      let ocamlc = Prog.get_ocamlc () in
      let ctypes_libs = get_ctypes_libs bstate in
      let bindings_cmo = build_dir </> fn (Compat.string_uncapitalize bindings_module ^ ".cmo") in
      let include_args = List.concat [
        Utils.to_include_path_options ctypes_includes;
        Utils.to_include_path_options [build_dir];
        Utils.to_include_path_options src_dirs;
        Utils.to_include_path_options [autogen_dir];
      ] in
      let lib_args = List.map fp_to_string ctypes_libs in
      (* Check if bindings.cmo exists *)
      let bindings_exists = Filesystem.exists bindings_cmo in
      (* Link with ctypes libs and the user's bindings module *)
      let compile_args = [ocamlc] @ include_args @ lib_args @
        (if bindings_exists then [fp_to_string bindings_cmo] else []) @
        ["-o"; fp_to_string discover_exe; fp_to_string discover_ml] in

      log Report "  Compiling type discovery program...\n%!";
      (match Process.run compile_args with
      | Process.Failure err ->
        log Report "  Warning: Failed to compile discover.ml: %s\n%!" err;
        log Report "  Falling back to static type sizes\n%!";
        (* Fallback: generate static content *)
        let content = Printf.sprintf
          "(* Auto-generated type bindings for %s *)\n\
           (* Generated statically - type discovery compilation failed *)\n\
           \n\
           let size_t_size = %d\n"
          (Libname.to_string lib)
          (Sys.word_size / 8)
        in
        Filesystem.write_file target_file content;
        Scheduler.FinishTask task
      | Process.Success _ ->
        (* Run discover to generate C code *)
        log Report "  Running type discovery program...\n%!";
        (match Process.run [fp_to_string discover_exe] with
        | Process.Failure err ->
          log Report "  Warning: Failed to run discover: %s\n%!" err;
          let content = Printf.sprintf
            "(* Auto-generated type bindings for %s *)\n\
             let size_t_size = %d\n"
            (Libname.to_string lib)
            (Sys.word_size / 8)
          in
          Filesystem.write_file target_file content;
          Scheduler.FinishTask task
        | Process.Success (c_code, _, _) ->
          (* Write the C program *)
          let discover_c = autogen_dir </> fn "discover.c" in
          Filesystem.write_file discover_c c_code;
          log Report "  Generated %s\n%!" (fp_to_string discover_c);

          (* Compile the C program - include ctypes directory for ctypes_cstubs_internals.h *)
          let discover_c_exe = autogen_dir </> fn "discover_c" in
          let cc = Prog.get_cc () in
          let ocaml_include = Analyze.get_ocaml_config_key "standard_library" bstate.bstate_config in
          (* Get ctypes include paths for ctypes_cstubs_internals.h *)
          let ctypes_c_includes = List.concat (List.map
            (fun p -> ["-I"; fp_to_string p])
            (ctypes_includes @ src_dirs)) in
          let compile_c_args = [cc; "-I"; ocaml_include] @ ctypes_c_includes @
            ["-o"; fp_to_string discover_c_exe; fp_to_string discover_c] in

          log Report "  Compiling C type discovery...\n%!";
          (match Process.run compile_c_args with
          | Process.Failure err ->
            log Report "  Warning: Failed to compile discover.c: %s\n%!" err;
            let content = Printf.sprintf
              "(* Auto-generated type bindings for %s *)\n\
               let size_t_size = %d\n"
              (Libname.to_string lib)
              (Sys.word_size / 8)
            in
            Filesystem.write_file target_file content;
            Scheduler.FinishTask task
          | Process.Success _ ->
            (* Run the C program to get types *)
            log Report "  Running C type discovery...\n%!";
            (match Process.run [fp_to_string discover_c_exe] with
            | Process.Failure err ->
              log Report "  Warning: Failed to run C discover: %s\n%!" err;
              let content = Printf.sprintf
                "(* Auto-generated type bindings for %s *)\n\
                 let size_t_size = %d\n"
                (Libname.to_string lib)
                (Sys.word_size / 8)
              in
              Filesystem.write_file target_file content;
              Scheduler.FinishTask task
            | Process.Success (ml_code, _, _) ->
              Filesystem.write_file target_file ml_code;
              log Report "  Generated %s\n%!" (fp_to_string target_file);
              ignore (bindings_module, types_functor);
              Scheduler.FinishTask task
            )
          )
        )
      )

(* Generate ctypes.cstubs function stubs - produces C.ml and stubs.c *)
let generate_cstubs_functions task_index task lib bstate task_context dag =
  let (cstate, target) = Hashtbl.find task_context task in
  let (nb_step, nb_step_len) = get_nb_step dag in
  log Report "[%*d of %d] Generating cstubs functions for %s\n%!" nb_step_len task_index nb_step
    (Libname.to_string lib);
  match target.target_cstubs with
  | None ->
    log Report "  No cstubs configuration found\n%!";
    Scheduler.FinishTask task
  | Some cstubs ->
    let autogen_dir = Dist.get_build_exn Dist.Autogen </> fn (Libname.to_string lib) in
    Filesystem.mkdir_safe autogen_dir 0o755;
    let entry_point_name = cstubs.cstubs_generated_entry_point in
    let c_lib_name = cstubs.cstubs_external_library_name in
    let generated_types = cstubs.cstubs_generated_types in

    match cstubs.cstubs_function_description with
    | None ->
      (* No function description - generate minimal entry point *)
      let entry_file = autogen_dir </> fn (Compat.string_uncapitalize entry_point_name ^ ".ml") in
      let entry_content = Printf.sprintf
        "(* Auto-generated entry point for %s *)\n\
         module Types = %s\n\
         module Functions = struct end\n"
        (Libname.to_string lib)
        generated_types
      in
      Filesystem.write_file entry_file entry_content;
      (* Generate empty C stubs *)
      let c_stubs_file = autogen_dir </> fn (c_lib_name ^ "_stubs.c") in
      Filesystem.write_file c_stubs_file
        "/* Auto-generated C stubs - no functions bound */\n\
         #include <caml/mlvalues.h>\n";
      log Report "  Generated %s (no functions)\n%!" (fp_to_string entry_file);
      Scheduler.FinishTask task
    | Some func_desc ->
      let bindings_hier = func_desc.Target.cstubs_functor in
      let bindings_parts = Hier.to_string bindings_hier in
      let parts = String_utils.split '.' bindings_parts in
      let (bindings_module, functions_functor) = match parts with
        | [m; f] -> (m, f)
        | [m] -> (m, "Functions")
        | m :: _ -> (m, "Functions")
        | [] -> (bindings_parts, "Functions")
      in

      (* Get types functor name from type description *)
      let types_functor = match cstubs.cstubs_type_description with
        | Some type_desc ->
          let type_parts = String_utils.split '.' (Hier.to_string type_desc.Target.cstubs_functor) in
          (match type_parts with
           | [_; f] -> f
           | [_] -> "Types"
           | _ -> "Types")
        | None -> "Types"
      in

      (* Get paths *)
      let ctypes_includes = get_ctypes_includes bstate in
      let ctypes_libs = get_ctypes_libs bstate in
      let build_dir = cstate.compilation_builddir_ml Normal in
      let src_dirs = target.target_obits.target_srcdir in
      (* Write all generated ML files to autogen directory - no placeholders needed *)
      let ml_output_dir = autogen_dir in
      ignore src_dirs;

      (* Path to compiled bindings module and generated types module *)
      let bindings_cmo = build_dir </> fn (Compat.string_uncapitalize bindings_module ^ ".cmo") in
      let types_cmo = build_dir </> fn (Compat.string_uncapitalize generated_types ^ ".cmo") in

      (* Generate stubgen.ml *)
      let stubgen_ml = autogen_dir </> fn "stubgen.ml" in
      let prefix = c_lib_name in
      let entry_file_name = Compat.string_uncapitalize entry_point_name ^ ".ml" in
      let stubs_file_name = c_lib_name ^ "_stubs.c" in

      (* Generate a module name for the generated FOREIGN implementation *)
      let generated_foreign_name = c_lib_name ^ "_generated" in
      let generated_foreign_file = Compat.string_uncapitalize generated_foreign_name ^ ".ml" in

      (* Convert concurrency policy to Cstubs module value string *)
      let concurrency_str = match cstubs.cstubs_concurrency with
        | Target.Cstubs_sequential -> "Cstubs.sequential"
        | Target.Cstubs_unlocked -> "Cstubs.unlocked"
        | Target.Cstubs_lwt_jobs -> "Cstubs.lwt_jobs"
        | Target.Cstubs_lwt_preemptive -> "Cstubs.lwt_preemptive"
      in

      (* Convert errno policy to Cstubs module value string *)
      let errno_str = match cstubs.cstubs_errno with
        | Target.Cstubs_ignore_errno -> "Cstubs.ignore_errno"
        | Target.Cstubs_return_errno -> "Cstubs.return_errno"
      in

      (* Generate header includes for C stubs *)
      let headers_includes = String.concat ""
        (List.map (fun h -> Printf.sprintf "  Format.fprintf c_fmt \"#include <%s>\\n\";\n" h)
           cstubs.cstubs_headers)
      in

      let has_types = match cstubs.cstubs_type_description with Some _ -> true | None -> false in
      let apply_types = if has_types then "(Types)" else "" in
      let types_def = if has_types then
        Printf.sprintf "  let module Types = %s.%s(%s) in\n" bindings_module types_functor (Compat.string_capitalize generated_types)
      else "" in

      let stubgen_content = Printf.sprintf
        "(* Auto-generated stub generator for %s *)\n\
         let prefix = \"%s\"\n\
         let autogen_dir = \"%s\"\n\
         let ml_output_dir = \"%s\"\n\
         \n\
         let () =\n\
        \  (* Generate C stubs to autogen directory *)\n\
        \  let c_file = open_out (Filename.concat autogen_dir \"%s\") in\n\
        \  let c_fmt = Format.formatter_of_out_channel c_file in\n\
        \  Format.fprintf c_fmt \"/* Auto-generated by ctypes.cstubs */\\n\";\n\
        \  Format.fprintf c_fmt \"#include <caml/mlvalues.h>\\n\";\n\
        \  Format.fprintf c_fmt \"#include <caml/memory.h>\\n\";\n\
        \  Format.fprintf c_fmt \"#include <caml/alloc.h>\\n\";\n\
        \  Format.fprintf c_fmt \"#include <caml/custom.h>\\n\";\n\
        \  Format.fprintf c_fmt \"#include <caml/callback.h>\\n\";\n\
        \  Format.fprintf c_fmt \"#include <caml/fail.h>\\n\";\n\
        \  Format.fprintf c_fmt \"#include <string.h>\\n\";\n\
         %s\
        \  Format.fprintf c_fmt \"\\n\";\n\
        \  (* Apply user's Functions functor to both FOREIGN and discovered TYPES *)\n\
        \  %s\
        \  let module M (F : Ctypes.FOREIGN) = %s.%s(F)%s in\n\
        \  Cstubs.write_c c_fmt ~concurrency:%s ~errno:%s ~prefix (module M);\n\
        \  close_out c_file;\n\
         \n\
        \  (* Generate FOREIGN implementation module to source directory *)\n\
        \  let foreign_file = open_out (Filename.concat ml_output_dir \"%s\") in\n\
        \  let foreign_fmt = Format.formatter_of_out_channel foreign_file in\n\
        \  Format.fprintf foreign_fmt \"(* Auto-generated FOREIGN implementation for %s *)\\n\";\n\
        \  Cstubs.write_ml foreign_fmt ~concurrency:%s ~errno:%s ~prefix (module M);\n\
        \  close_out foreign_file;\n\
         \n\
        \  (* Generate entry point that applies user's functor to generated module *)\n\
        \  let entry_file = open_out (Filename.concat ml_output_dir \"%s\") in\n\
        \  let entry_fmt = Format.formatter_of_out_channel entry_file in\n\
        \  Format.fprintf entry_fmt \"(* Auto-generated entry point for %s *)\\n\";\n\
        \  Format.fprintf entry_fmt \"(* Apply user's Types functor to generated TYPE implementation for struct layouts *)\\n\";\n\
        \  Format.fprintf entry_fmt \"module Types = %s.%s(%s)\\n\\n\";\n\
        \  Format.fprintf entry_fmt \"(* Apply user's Functions functor to generated FOREIGN implementation *)\\n\";\n\
        \  Format.fprintf entry_fmt \"module C_Functions = %s.%s(%s)%s\\n\";\n\
        \  close_out entry_file;\n\
         \n\
        \  print_endline \"Stub generation complete\"\n"
        (Libname.to_string lib) prefix (fp_to_string autogen_dir) (fp_to_string ml_output_dir)
        stubs_file_name headers_includes
        types_def bindings_module functions_functor apply_types
        concurrency_str errno_str
        generated_foreign_file (Libname.to_string lib)
        concurrency_str errno_str
        entry_file_name (Libname.to_string lib)
        bindings_module types_functor (Compat.string_capitalize generated_types)
        bindings_module functions_functor
        (Compat.string_capitalize generated_foreign_name)
        (if has_types then "(Types)" else "")
      in
      Filesystem.write_file stubgen_ml stubgen_content;
      log Report "  Generated %s\n%!" (fp_to_string stubgen_ml);

      (* Compile stubgen.ml *)
      let stubgen_exe = autogen_dir </> fn "stubgen.byte" in
      let ocamlc = Prog.get_ocamlc () in
      let include_args = List.concat [
        Utils.to_include_path_options ctypes_includes;
        Utils.to_include_path_options [build_dir];
        Utils.to_include_path_options src_dirs;
      ] in
      let lib_args = List.map fp_to_string ctypes_libs in

      (* Check if bindings and types modules exist *)
      let bindings_exists = Filesystem.exists bindings_cmo in
      let types_exists = Filesystem.exists types_cmo in
      log Report "  Bindings module at %s: %s\n%!"
        (fp_to_string bindings_cmo) (if bindings_exists then "found" else "not found");
      log Report "  Types generated module at %s: %s\n%!"
        (fp_to_string types_cmo) (if types_exists then "found" else "not found");

      (* Compile and link user provided C sources *)
      let c_objs = List.map (fun c_fn ->
        let c_src = fn_to_string c_fn in
        let dst_file = autogen_dir </> o_from_cfile c_fn in
        let src_file = target.target_cbits.target_cdir </> c_fn in
        let cc = Prog.get_cc () in
        let include_args = Utils.to_include_path_options (cstate.compilation_c_include_paths @ ctypes_includes @ src_dirs) in
        let args = [cc] @ include_args @ ["-o"; fp_to_string dst_file; "-c"; fp_to_string src_file] in
        log Report "  Compiling C source %s for stubgen...\n%!" c_src;
        (match Process.run args with
         | Process.Failure err -> failwith ("Failed to compile C source " ^ c_src ^ ": " ^ err)
         | Process.Success _ -> ());
        fp_to_string dst_file
      ) target.target_cbits.target_csources in

      let compile_args = [ocamlc] @ include_args @ lib_args @
        (if bindings_exists then [fp_to_string bindings_cmo] else []) @
        (if types_exists then [fp_to_string types_cmo] else []) @
        c_objs @
        ["-o"; fp_to_string stubgen_exe; fp_to_string stubgen_ml] in

      log Report "  Compiling stub generator...\n%!";
      (match Process.run compile_args with
      | Process.Failure err ->
        log Report "  Warning: Failed to compile stubgen.ml: %s\n%!" err;
        log Report "  Falling back to placeholder stubs\n%!";
        (* Fallback: generate placeholder content *)
        let entry_file = autogen_dir </> fn (Compat.string_uncapitalize entry_point_name ^ ".ml") in
        let entry_content = Printf.sprintf
          "(* Auto-generated entry point for %s *)\n\
           (* Stub generation failed - placeholder *)\n\
           \n\
           module Types = %s\n\
           \n\
           module Functions = struct\n\
          \  (* Function stubs would be here *)\n\
           end\n"
          (Libname.to_string lib)
          generated_types
        in
        Filesystem.write_file entry_file entry_content;
        let c_stubs_file = autogen_dir </> fn (c_lib_name ^ "_stubs.c") in
        Filesystem.write_file c_stubs_file
          "/* Auto-generated C stubs - placeholder */\n\
           #include <caml/mlvalues.h>\n\
           #include <caml/memory.h>\n\
           #include <caml/alloc.h>\n";
        log Report "  Generated placeholder stubs\n%!";
        Scheduler.FinishTask task
      | Process.Success _ ->
        (* Run stubgen *)
        log Report "  Running stub generator...\n%!";
        (match Process.run [fp_to_string stubgen_exe] with
        | Process.Failure err ->
          log Report "  Warning: Failed to run stubgen: %s\n%!" err;
          (* Fallback *)
          let entry_file = autogen_dir </> fn (Compat.string_uncapitalize entry_point_name ^ ".ml") in
          let entry_content = Printf.sprintf
            "(* Auto-generated entry point for %s *)\n\
             module Types = %s\n\
             module Functions = struct end\n"
            (Libname.to_string lib)
            generated_types
          in
          Filesystem.write_file entry_file entry_content;
          let c_stubs_file = autogen_dir </> fn (c_lib_name ^ "_stubs.c") in
          Filesystem.write_file c_stubs_file
            "/* Auto-generated C stubs */\n\
             #include <caml/mlvalues.h>\n";
          Scheduler.FinishTask task
        | Process.Success (output, _, _) ->
          log Report "  %s\n%!" output;
          log Report "  Stubs generated successfully\n%!";
          Scheduler.FinishTask task
        )
      )

(* Compile generated ctypes.cstubs C code *)
let compile_cstubs_c task_index task lib bstate task_context dag =
  let (cstate, target) = Hashtbl.find task_context task in
  let (nb_step, nb_step_len) = get_nb_step dag in
  log Report "[%*d of %d] Compiling cstubs C for %s\n%!" nb_step_len task_index nb_step
    (Libname.to_string lib);
  match target.target_cstubs with
  | None ->
    log Report "  No cstubs configuration found\n%!";
    Scheduler.FinishTask task
  | Some cstubs ->
    let autogen_dir = Dist.get_build_exn Dist.Autogen </> fn (Libname.to_string lib) in
    let c_lib_name = cstubs.cstubs_external_library_name in
    let c_stubs_file = fn (c_lib_name ^ "_stubs.c") in
    (* Add ctypes include paths for C headers like ctypes_cstubs_internals.h *)
    let ctypes_c_includes = get_ctypes_includes bstate in
    let src_dirs = target.target_obits.target_srcdir in
    let c_dir_spec = {
      include_dirs = cstate.compilation_c_include_paths @ ctypes_c_includes @ src_dirs;
      dst_dir      = autogen_dir;
      src_dir      = autogen_dir
    } in
    let dest = (Filetype.FileO, c_dir_spec.dst_dir </> o_from_cfile c_stubs_file) in
    log Report "  Compiling %s -> %s\n%!" (fn_to_string c_stubs_file) (fp_to_string (snd dest));
    (* Use the C compiler to compile the stubs *)
    Scheduler.AddProcess (task, run_c_compile bstate.bstate_config c_dir_spec [] c_stubs_file)