1OCAMLOPT(1) General Commands Manual OCAMLOPT(1)
2
6 ocamlopt - The OCaml native-code compiler
7
10 ocamlopt [ options ] filename ...
11 ocamlopt.opt (same options)
13
16 The OCaml high-performance native-code compiler ocamlopt(1) compiles
17 OCaml source files to native code object files and link these object
18 files to produce standalone executables.
19 The ocamlopt(1) command has a command-line interface very close to that
21 of ocamlc(1). It accepts the same types of arguments and processes
22 them sequentially, after all options have been processed:
23 Arguments ending in .mli are taken to be source files for compilation
25 unit interfaces. Interfaces specify the names exported by compilation
26 units: they declare value names with their types, define public data
27 types, declare abstract data types, and so on. From the file x.mli, the
28 ocamlopt(1) compiler produces a compiled interface in the file x.cmi.
29 The interface produced is identical to that produced by the bytecode
30 compiler ocamlc(1).
31 Arguments ending in .ml are taken to be source files for compilation
33 unit implementations. Implementations provide definitions for the names
34 exported by the unit, and also contain expressions to be evaluated for
35 their side-effects. From the file x.ml, the ocamlopt(1) compiler pro‐
36 duces two files: x.o, containing native object code, and x.cmx, con‐
37 taining extra information for linking and optimization of the clients
38 of the unit. The compiled implementation should always be referred to
39 under the name x.cmx (when given a .o file, ocamlopt(1) assumes that it
40 contains code compiled from C, not from OCaml).
41 The implementation is checked against the interface file x.mli (if it
43 exists) as described in the manual for ocamlc(1).
44 Arguments ending in .cmx are taken to be compiled object code. These
46 files are linked together, along with the object files obtained by com‐
47 piling .ml arguments (if any), and the OCaml standard library, to pro‐
48 duce a native-code executable program. The order in which .cmx and .ml
49 arguments are presented on the command line is relevant: compilation
50 units are initialized in that order at run-time, and it is a link-time
51 error to use a component of a unit before having initialized it. Hence,
52 a given x.cmx file must come before all .cmx files that refer to the
53 unit x.
54 Arguments ending in .cmxa are taken to be libraries of object code.
56 Such a library packs in two files lib.cmxa and lib.a a set of object
57 files (.cmx/.o files). Libraries are build with ocamlopt -a (see the
58 description of the -a option below). The object files contained in the
59 library are linked as regular .cmx files (see above), in the order
60 specified when the library was built. The only difference is that if an
61 object file contained in a library is not referenced anywhere in the
62 program, then it is not linked in.
63 Arguments ending in .c are passed to the C compiler, which generates a
65 .o object file. This object file is linked with the program.
66 Arguments ending in .o or .a are assumed to be C object files and li‐
68 braries. They are linked with the program.
69 The output of the linking phase is a regular Unix executable file. It
71 does not need ocamlrun(1) to run.
72 ocamlopt.opt is the same compiler as ocamlopt, but compiled with itself
74 instead of with the bytecode compiler ocamlc(1). Thus, it behaves ex‐
75 actly like ocamlopt, but compiles faster. ocamlopt.opt is not avail‐
76 able in all installations of OCaml.
77
80 The following command-line options are recognized by ocamlopt(1).
81 -a Build a library (.cmxa/.a file) with the object files (.cmx/.o
83 files) given on the command line, instead of linking them into
84 an executable file. The name of the library must be set with the
85 -o option.
86 If -cclib or -ccopt options are passed on the command line,
88 these options are stored in the resulting .cmxa library. Then,
89 linking with this library automatically adds back the
90 -cclib and -ccopt options as if they had been provided on the
91 command line, unless the -noautolink option is given. Addition‐
92 ally, a substring $CAMLORIGIN inside a -ccopt options will be
93 replaced by the full path to the .cma library, excluding the
94 filename.
95 -absname
97 Show absolute filenames in error messages.
98 -annot Deprecated since OCaml 4.11. Please use -bin-annot instead.
100 -bin-annot
102 Dump detailed information about the compilation (types, bind‐
103 ings, tail-calls, etc) in binary format. The information for
104 file src.ml is put into file src.cmt. In case of a type error,
105 dump all the information inferred by the type-checker before the
106 error. The annotation files produced by -bin-annot contain more
107 information and are much more compact than the files produced by
108 -annot.
109 -c Compile only. Suppress the linking phase of the compilation.
111 Source code files are turned into compiled files, but no exe‐
112 cutable file is produced. This option is useful to compile mod‐
113 ules separately.
114 -cc ccomp
116 Use ccomp as the C linker called to build the final executable
117 and as the C compiler for compiling .c source files.
118 -cclib -llibname
120 Pass the -llibname option to the linker. This causes the given C
121 library to be linked with the program.
122 -ccopt option
124 Pass the given option to the C compiler and linker. For in‐
125 stance, -ccopt -Ldir causes the C linker to search for C li‐
126 braries in directory dir.
127 -color mode
129 Enable or disable colors in compiler messages (especially warn‐
130 ings and errors). The following modes are supported:
131 auto use heuristics to enable colors only if the output supports
133 them (an ANSI-compatible tty terminal);
134 always enable colors unconditionally;
136 never disable color output.
138 The environment variable "OCAML_COLOR" is considered if -color
140 is not provided. Its values are auto/always/never as above.
141 If -color is not provided, "OCAML_COLOR" is not set and the en‐
143 vironment variable "NO_COLOR" is set, then color output is dis‐
144 abled. Otherwise, the default setting is auto, and the current
145 heuristic checks that the "TERM" environment variable exists and
146 is not empty or "dumb", and that isatty(stderr) holds.
147 -error-style mode
150 Control the way error messages and warnings are printed. The
151 following modes are supported:
152 short only print the error and its location;
154 contextual like "short", but also display the source code snip‐
156 pet corresponding to the location of the error.
157 The default setting is contextual.
159 The environment variable "OCAML_ERROR_STYLE" is considered if
161 -error-style is not provided. Its values are short/contextual as
162 above.
163 -compact
166 Optimize the produced code for space rather than for time. This
167 results in smaller but slightly slower programs. The default is
168 to optimize for speed.
169 -config
171 Print the version number of ocamlopt(1) and a detailed summary
172 of its configuration, then exit.
173 -config-var
175 Print the value of a specific configuration variable from the
176 -config output, then exit. If the variable does not exist, the
177 exit code is non-zero.
178 -depend ocamldep-args
180 Compute dependencies, as ocamldep would do.
181 -for-pack module-path
183 Generate an object file (.cmx and .o files) that can later be
184 included as a sub-module (with the given access path) of a com‐
185 pilation unit constructed with -pack. For instance, ocam‐
186 lopt -for-pack P -c A.ml will generate a.cmx and a.o files that
187 can later be used with ocamlopt -pack -o P.cmx a.cmx.
188 -g Add debugging information while compiling and linking. This op‐
190 tion is required in order to produce stack backtraces when the
191 program terminates on an uncaught exception (see ocamlrun(1)).
192 -i Cause the compiler to print all defined names (with their in‐
194 ferred types or their definitions) when compiling an implementa‐
195 tion (.ml file). No compiled files (.cmo and .cmi files) are
196 produced. This can be useful to check the types inferred by the
197 compiler. Also, since the output follows the syntax of inter‐
198 faces, it can help in writing an explicit interface (.mli file)
199 for a file: just redirect the standard output of the compiler to
200 a .mli file, and edit that file to remove all declarations of
201 unexported names.
202 -I directory
204 Add the given directory to the list of directories searched for
205 compiled interface files (.cmi), compiled object code files
206 (.cmx), and libraries (.cmxa). By default, the current directory
207 is searched first, then the standard library directory. Directo‐
208 ries added with -I are searched after the current directory, in
209 the order in which they were given on the command line, but be‐
210 fore the standard library directory. See also option -nostdlib.
211 If the given directory starts with +, it is taken relative to
213 the standard library directory. For instance, -I +compiler-libs
214 adds the subdirectory compiler-libs of the standard library to
215 the search path.
216 -impl filename
218 Compile the file filename as an implementation file, even if its
219 extension is not .ml.
220 -inline n
222 Set aggressiveness of inlining to n, where n is a positive inte‐
223 ger. Specifying -inline 0 prevents all functions from being in‐
224 lined, except those whose body is smaller than the call site.
225 Thus, inlining causes no expansion in code size. The default ag‐
226 gressiveness, -inline 1, allows slightly larger functions to be
227 inlined, resulting in a slight expansion in code size. Higher
228 values for the -inline option cause larger and larger functions
229 to become candidate for inlining, but can result in a serious
230 increase in code size.
231 -insn-sched
233 Enables the instruction scheduling pass in the compiler backend.
234 -intf filename
236 Compile the file filename as an interface file, even if its ex‐
237 tension is not .mli.
238 -intf-suffix string
240 Recognize file names ending with string as interface files (in‐
241 stead of the default .mli).
242 -keep-docs
244 Keep documentation strings in generated .cmi files.
245 -keep-locs
247 Keep locations in generated .cmi files.
248 -labels
250 Labels are not ignored in types, labels may be used in applica‐
251 tions, and labelled parameters can be given in any order. This
252 is the default.
253 -linkall
255 Force all modules contained in libraries to be linked in. If
256 this flag is not given, unreferenced modules are not linked in.
257 When building a library (-a flag), setting the -linkall flag
258 forces all subsequent links of programs involving that library
259 to link all the modules contained in the library. When compil‐
260 ing a module (option -c), setting the -linkall option ensures
261 that this module will always be linked if it is put in a library
262 and this library is linked.
263 -linscan
265 Use linear scan register allocation. Compiling with this allo‐
266 cator is faster than with the usual graph coloring allocator,
267 sometimes quite drastically so for long functions and modules.
268 On the other hand, the generated code can be a bit slower.
269 -match-context-rows
271 Set number of rows of context used during pattern matching com‐
272 pilation. Lower values cause faster compilation, but less opti‐
273 mized code. The default value is 32.
274 -no-alias-deps
276 Do not record dependencies for module aliases.
277 -no-app-funct
279 Deactivates the applicative behaviour of functors. With this op‐
280 tion, each functor application generates new types in its result
281 and applying the same functor twice to the same argument yields
282 two incompatible structures.
283 -noassert
285 Do not compile assertion checks. Note that the special form as‐
286 sert false is always compiled because it is typed specially.
287 This flag has no effect when linking already-compiled files.
288 -noautolink
290 When linking .cmxa libraries, ignore -cclib and -ccopt options
291 potentially contained in the libraries (if these options were
292 given when building the libraries). This can be useful if a li‐
293 brary contains incorrect specifications of C libraries or C op‐
294 tions; in this case, during linking, set -noautolink and pass
295 the correct C libraries and options on the command line.
296 -nodynlink
298 Allow the compiler to use some optimizations that are valid only
299 for code that is never dynlinked.
300 -no-insn-sched
302 Disables the instruction scheduling pass in the compiler back‐
303 end.
304 -nostdlib
306 Do not automatically add the standard library directory to the
307 list of directories searched for compiled interface files
308 (.cmi), compiled object code files (.cmx), and libraries
309 (.cmxa). See also option -I.
310 -nolabels
312 Ignore non-optional labels in types. Labels cannot be used in
313 applications, and parameter order becomes strict.
314 -o exec-file
316 Specify the name of the output file produced by the linker. The
317 default output name is a.out, in keeping with the Unix tradi‐
318 tion. If the -a option is given, specify the name of the library
319 produced. If the -pack option is given, specify the name of the
320 packed object file produced. If the -output-obj option is
321 given, specify the name of the output file produced. If the
322 -shared option is given, specify the name of plugin file pro‐
323 duced. This can also be used when compiling an interface or im‐
324 plementation file, without linking, in which case it sets the
325 name of the cmi or cmo file, and also sets the module name to
326 the file name up to the first dot.
327 -opaque
329 When compiling a .mli interface file, this has the same effect
330 as the -opaque option of the bytecode compiler. When compiling a
331 .ml implementation file, this produces a .cmx file without
332 cross-module optimization information, which reduces recompila‐
333 tion on module change.
334 -open module
336 Opens the given module before processing the interface or imple‐
337 mentation files. If several -open options are given, they are
338 processed in order, just as if the statements open! module1;;
339 ... open! moduleN;; were added at the top of each file.
340 -output-obj
342 Cause the linker to produce a C object file instead of an exe‐
343 cutable file. This is useful to wrap OCaml code as a C library,
344 callable from any C program. The name of the output object file
345 must be set with the -o option. This option can also be used to
346 produce a compiled shared/dynamic library (.so extension).
347 -output-complete-obj Same as -output-obj except the object file
348 produced includes the runtime and autolink libraries.
349 -pack Build an object file (.cmx and .o files) and its associated com‐
352 piled interface (.cmi) that combines the .cmx object files given
353 on the command line, making them appear as sub-modules of the
354 output .cmx file. The name of the output .cmx file must be
355 given with the -o option. For instance, ocam‐
356 lopt -pack -o P.cmx A.cmx B.cmx C.cmx generates compiled files
357 P.cmx, P.o and P.cmi describing a compilation unit having three
358 sub-modules A, B and C, corresponding to the contents of the ob‐
359 ject files A.cmx, B.cmx and C.cmx. These contents can be refer‐
360 enced as P.A, P.B and P.C in the remainder of the program.
361 The .cmx object files being combined must have been compiled
363 with the appropriate -for-pack option. In the example above,
364 A.cmx, B.cmx and C.cmx must have been compiled with ocam‐
365 lopt -for-pack P.
366 Multiple levels of packing can be achieved by combining -pack
368 with -for-pack. See The OCaml user's manual, chapter "Native-
369 code compilation" for more details.
370 -pp command
372 Cause the compiler to call the given command as a preprocessor
373 for each source file. The output of command is redirected to an
374 intermediate file, which is compiled. If there are no compila‐
375 tion errors, the intermediate file is deleted afterwards.
376 -ppx command
378 After parsing, pipe the abstract syntax tree through the pre‐
379 processor command. The module Ast_mapper(3) implements the ex‐
380 ternal interface of a preprocessor.
381 -principal
383 Check information path during type-checking, to make sure that
384 all types are derived in a principal way. All programs accepted
385 in -principal mode are also accepted in default mode with equiv‐
386 alent types, but different binary signatures.
387 -rectypes
389 Allow arbitrary recursive types during type-checking. By de‐
390 fault, only recursive types where the recursion goes through an
391 object type are supported. Note that once you have created an
392 interface using this flag, you must use it again for all depen‐
393 dencies.
394 -runtime-variant suffix
396 Add suffix to the name of the runtime library that will be used
397 by the program. If OCaml was configured with option -with-de‐
398 bug-runtime, then the d suffix is supported and gives a debug
399 version of the runtime.
400 -S Keep the assembly code produced during the compilation. The as‐
402 sembly code for the source file x.ml is saved in the file x.s.
403 -stop-after pass
405 Stop compilation after the given compilation pass. The currently
406 supported passes are: parsing, typing, scheduling, emit.
407 -save-ir-after pass
409 Save intermediate representation after the given compilation
410 pass. The currently supported passes are: scheduling.
411 -safe-string
413 Enforce the separation between types string and bytes, thereby
414 making strings read-only. This is the default.
415 -shared
417 Build a plugin (usually .cmxs) that can be dynamically loaded
418 with the Dynlink module. The name of the plugin must be set with
419 the -o option. A plugin can include a number of OCaml modules
420 and libraries, and extra native objects (.o, .a files). Build‐
421 ing native plugins is only supported for some operating system.
422 Under some systems (currently, only Linux AMD 64), all the OCaml
423 code linked in a plugin must have been compiled without the -no‐
424 dynlink flag. Some constraints might also apply to the way the
425 extra native objects have been compiled (under Linux AMD 64,
426 they must contain only position-independent code).
427 -short-paths
429 When a type is visible under several module-paths, use the
430 shortest one when printing the type's name in inferred inter‐
431 faces and error and warning messages.
432 -strict-sequence
434 The left-hand part of a sequence must have type unit.
435 -unboxed-types
437 When a type is unboxable (i.e. a record with a single argument
438 or a concrete datatype with a single constructor of one argu‐
439 ment) it will be unboxed unless annotated with [@@ocaml.boxed].
440 -no-unboxed-types
442 When a type is unboxable it will be boxed unless annotated with
443 [@@ocaml.unboxed]. This is the default.
444 -unsafe
446 Turn bound checking off for array and string accesses (the
447 v.(i)ands.[i] constructs). Programs compiled with -unsafe are
448 therefore faster, but unsafe: anything can happen if the program
449 accesses an array or string outside of its bounds. Additionally,
450 turn off the check for zero divisor in integer division and mod‐
451 ulus operations. With -unsafe, an integer division (or modulus)
452 by zero can halt the program or continue with an unspecified re‐
453 sult instead of raising a Division_by_zero exception.
454 -unsafe-string
456 Identify the types string and bytes, thereby making strings
457 writable. This is intended for compatibility with old source
458 code and should not be used with new software.
459 -v Print the version number of the compiler and the location of the
461 standard library directory, then exit.
462 -verbose
464 Print all external commands before they are executed, in partic‐
465 ular invocations of the assembler, C compiler, and linker.
466 -version or -vnum
468 Print the version number of the compiler in short form (e.g.
469 "3.11.0"), then exit.
470 -w warning-list
472 Enable, disable, or mark as fatal the warnings specified by the
473 argument warning-list. See ocamlc(1) for the syntax of warning-
474 list.
475 -warn-error warning-list
477 Mark as fatal the warnings specified in the argument warn‐
478 ing-list. The compiler will stop with an error when one of
479 these warnings is emitted. The warning-list has the same mean‐
480 ing as for the -w option: a + sign (or an uppercase letter)
481 marks the corresponding warnings as fatal, a - sign (or a lower‐
482 case letter) turns them back into non-fatal warnings, and a @
483 sign both enables and marks as fatal the corresponding warnings.
484 Note: it is not recommended to use the -warn-error option in
486 production code, because it will almost certainly prevent com‐
487 piling your program with later versions of OCaml when they add
488 new warnings or modify existing warnings.
489 The default setting is -warn-error -a+31 (only warning 31 is fa‐
491 tal).
492 -warn-help
494 Show the description of all available warning numbers.
495 -where Print the location of the standard library, then exit.
497 -with-runtime
499 Include the runtime system in the generated program. This is the
500 default.
501 -without-runtime
503 The compiler does not include the runtime system (nor a refer‐
504 ence to it) in the generated program; it must be supplied sepa‐
505 rately.
506 - file Process file as a file name, even if it starts with a dash (-)
508 character.
509 -help or --help
511 Display a short usage summary and exit.
512
515 The IA32 code generator (Intel Pentium, AMD Athlon) supports the fol‐
516 lowing additional option:
517 -ffast-math
519 Use the IA32 instructions to compute trigonometric and exponen‐
520 tial functions, instead of calling the corresponding library
521 routines. The functions affected are: atan, atan2, cos, log,
522 log10, sin, sqrt and tan. The resulting code runs faster, but
523 the range of supported arguments and the precision of the result
524 can be reduced. In particular, trigonometric operations cos,
525 sin, tan have their range reduced to [-2^64, 2^64].
526
529 The AMD64 code generator (64-bit versions of Intel Pentium and AMD
530 Athlon) supports the following additional options:
531 -fPIC Generate position-independent machine code. This is the de‐
533 fault.
534 -fno-PIC
536 Generate position-dependent machine code.
537
540 The PowerPC code generator supports the following additional options:
541 -flarge-toc
543 Enables the PowerPC large model allowing the TOC (table of con‐
544 tents) to be arbitrarily large. This is the default since 4.11.
545 -fsmall-toc
547 Enables the PowerPC small model allowing the TOC to be up to 64
548 kbytes per compilation unit. Prior to 4.11 this was the default
549 behaviour. \nd{options}
550
553 The ARM code generator supports the following additional options:
554 -farch=armv4|armv5|armv5te|armv6|armv6t2|armv7
556 Select the ARM target architecture
557 -ffpu=soft|vfpv2|vfpv3-d16|vfpv3
559 Select the floating-point hardware
560 -fPIC Generate position-independent machine code.
562 -fno-PIC
564 Generate position-dependent machine code. This is the default.
565 -fthumb
567 Enable Thumb/Thumb-2 code generation
568 -fno-thumb
570 Disable Thumb/Thumb-2 code generation
571 The default values for target architecture, floating-point hardware and
573 thumb usage were selected at configure-time when building ocamlopt it‐
574 self. This configuration can be inspected using ocamlopt -config. Tar‐
575 get architecture depends on the "model" setting, while floating-point
576 hardware and thumb support are determined from the ABI setting in "sys‐
577 tem" ( linux_eabiorlinux_eabihf).
578
581 ocamlc(1).
582 The OCaml user's manual, chapter "Native-code compilation".
583 OCAMLOPT(1)