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
68 libraries. 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
75 exactly 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 Dump detailed information about the compilation (types, bind‐
100 ings, tail-calls, etc). The information for file src.ml is put
101 into file src.annot. In case of a type error, dump all the
102 information inferred by the type-checker before the error. The
103 src.annot file can be used with the emacs commands given in
104 emacs/caml-types.el to display types and other annotations
105 interactively.
106 -bin-annot
108 Dump detailed information about the compilation (types, bind‐
109 ings, tail-calls, etc) in binary format. The information for
110 file src.ml is put into file src.cmt. In case of a type error,
111 dump all the information inferred by the type-checker before the
112 error. The annotation files produced by -bin-annot contain more
113 information and are much more compact than the files produced by
114 -annot.
115 -c Compile only. Suppress the linking phase of the compilation.
117 Source code files are turned into compiled files, but no exe‐
118 cutable file is produced. This option is useful to compile mod‐
119 ules separately.
120 -cc ccomp
122 Use ccomp as the C linker called to build the final executable
123 and as the C compiler for compiling .c source files.
124 -cclib -llibname
126 Pass the -llibname option to the linker. This causes the given C
127 library to be linked with the program.
128 -ccopt option
130 Pass the given option to the C compiler and linker. For
131 instance, -ccopt -Ldir causes the C linker to search for C
132 libraries in directory dir.
133 -color mode
135 Enable or disable colors in compiler messages (especially warn‐
136 ings and errors). The following modes are supported:
137 auto use heuristics to enable colors only if the output supports
139 them (an ANSI-compatible tty terminal);
140 always enable colors unconditionally;
142 never disable color output.
144 The default setting is auto, and the current heuristic checks
146 that the "TERM" environment variable exists and is not empty or
147 "dumb", and that isatty(stderr) holds.
148 The environment variable "OCAML_COLOR" is considered if -color
150 is not provided. Its values are auto/always/never as above.
151 -error-style mode
154 Control the way error messages and warnings are printed. The
155 following modes are supported:
156 short only print the error and its location;
158 contextual like "short", but also display the source code snip‐
160 pet corresponding to the location of the error.
161 The default setting is contextual.
163 The environment variable "OCAML_ERROR_STYLE" is considered if
165 -error-style is not provided. Its values are short/contextual as
166 above.
167 -compact
170 Optimize the produced code for space rather than for time. This
171 results in smaller but slightly slower programs. The default is
172 to optimize for speed.
173 -config
175 Print the version number of ocamlopt(1) and a detailed summary
176 of its configuration, then exit.
177 -config-var
179 Print the value of a specific configuration variable from the
180 -config output, then exit. If the variable does not exist, the
181 exit code is non-zero.
182 -depend ocamldep-args
184 Compute dependencies, as ocamldep would do.
185 -for-pack module-path
187 Generate an object file (.cmx and .o files) that can later be
188 included as a sub-module (with the given access path) of a com‐
189 pilation unit constructed with -pack. For instance, ocam‐
190 lopt -for-pack P -c A.ml will generate a.cmx and a.o files that
191 can later be used with ocamlopt -pack -o P.cmx a.cmx.
192 -g Add debugging information while compiling and linking. This
194 option is required in order to produce stack backtraces when the
195 program terminates on an uncaught exception (see ocamlrun(1)).
196 -i Cause the compiler to print all defined names (with their
198 inferred types or their definitions) when compiling an implemen‐
199 tation (.ml file). No compiled files (.cmo and .cmi files) are
200 produced. This can be useful to check the types inferred by the
201 compiler. Also, since the output follows the syntax of inter‐
202 faces, it can help in writing an explicit interface (.mli file)
203 for a file: just redirect the standard output of the compiler to
204 a .mli file, and edit that file to remove all declarations of
205 unexported names.
206 -I directory
208 Add the given directory to the list of directories searched for
209 compiled interface files (.cmi), compiled object code files
210 (.cmx), and libraries (.cmxa). By default, the current directory
211 is searched first, then the standard library directory. Directo‐
212 ries added with -I are searched after the current directory, in
213 the order in which they were given on the command line, but
214 before the standard library directory. See also option -nost‐
215 dlib.
216 If the given directory starts with +, it is taken relative to
218 the standard library directory. For instance, -I +compiler-libs
219 adds the subdirectory compiler-libs of the standard library to
220 the search path.
221 -impl filename
223 Compile the file filename as an implementation file, even if its
224 extension is not .ml.
225 -inline n
227 Set aggressiveness of inlining to n, where n is a positive inte‐
228 ger. Specifying -inline 0 prevents all functions from being
229 inlined, except those whose body is smaller than the call site.
230 Thus, inlining causes no expansion in code size. The default
231 aggressiveness, -inline 1, allows slightly larger functions to
232 be inlined, resulting in a slight expansion in code size. Higher
233 values for the -inline option cause larger and larger functions
234 to become candidate for inlining, but can result in a serious
235 increase in code size.
236 -intf filename
238 Compile the file filename as an interface file, even if its
239 extension is not .mli.
240 -intf-suffix string
242 Recognize file names ending with string as interface files
243 (instead of the default .mli).
244 -keep-docs
246 Keep documentation strings in generated .cmi files.
247 -keep-locs
249 Keep locations in generated .cmi files.
250 -labels
252 Labels are not ignored in types, labels may be used in applica‐
253 tions, and labelled parameters can be given in any order. This
254 is the default.
255 -linkall
257 Force all modules contained in libraries to be linked in. If
258 this flag is not given, unreferenced modules are not linked in.
259 When building a library (-a flag), setting the -linkall flag
260 forces all subsequent links of programs involving that library
261 to link all the modules contained in the library. When compil‐
262 ing a module (option -c), setting the -linkall option ensures
263 that this module will always be linked if it is put in a library
264 and this library is linked.
265 -linscan
267 Use linear scan register allocation. Compiling with this allo‐
268 cator is faster than with the usual graph coloring allocator,
269 sometimes quite drastically so for long functions and modules.
270 On the other hand, the generated code can be a bit slower.
271 -match-context-rows
273 Set number of rows of context used during pattern matching com‐
274 pilation. Lower values cause faster compilation, but less opti‐
275 mized code. The default value is 32.
276 -no-alias-deps
278 Do not record dependencies for module aliases.
279 -no-app-funct
281 Deactivates the applicative behaviour of functors. With this
282 option, each functor application generates new types in its
283 result and applying the same functor twice to the same argument
284 yields two incompatible structures.
285 -noassert
287 Do not compile assertion checks. Note that the special form
288 assert false is always compiled because it is typed specially.
289 This flag has no effect when linking already-compiled files.
290 -noautolink
292 When linking .cmxa libraries, ignore -cclib and -ccopt options
293 potentially contained in the libraries (if these options were
294 given when building the libraries). This can be useful if a
295 library contains incorrect specifications of C libraries or C
296 options; in this case, during linking, set -noautolink and pass
297 the correct C libraries and options on the command line.
298 -nodynlink
300 Allow the compiler to use some optimizations that are valid only
301 for code that is never dynlinked.
302 -nostdlib
304 Do not automatically add the standard library directory to the
305 list of directories searched for compiled interface files
306 (.cmi), compiled object code files (.cmx), and libraries
307 (.cmxa). See also option -I.
308 -nolabels
310 Ignore non-optional labels in types. Labels cannot be used in
311 applications, and parameter order becomes strict.
312 -o exec-file
314 Specify the name of the output file produced by the linker. The
315 default output name is a.out, in keeping with the Unix tradi‐
316 tion. If the -a option is given, specify the name of the library
317 produced. If the -pack option is given, specify the name of the
318 packed object file produced. If the -output-obj option is
319 given, specify the name of the output file produced. If the
320 -shared option is given, specify the name of plugin file pro‐
321 duced. This can also be used when compiling an interface or
322 implementation file, without linking, in which case it sets the
323 name of the cmi or cmo file, and also sets the module name to
324 the file name up to the first dot.
325 -opaque
327 When compiling a .mli interface file, this has the same effect
328 as the -opaque option of the bytecode compiler. When compiling a
329 .ml implementation file, this produces a .cmx file without
330 cross-module optimization information, which reduces recompila‐
331 tion on module change.
332 -open module
334 Opens the given module before processing the interface or imple‐
335 mentation files. If several -open options are given, they are
336 processed in order, just as if the statements open! module1;;
337 ... open! moduleN;; were added at the top of each file.
338 -output-obj
340 Cause the linker to produce a C object file instead of an exe‐
341 cutable file. This is useful to wrap OCaml code as a C library,
342 callable from any C program. The name of the output object file
343 must be set with the -o option. This option can also be used to
344 produce a compiled shared/dynamic library (.so extension).
345 -p Generate extra code to write profile information when the pro‐
347 gram is executed. The profile information can then be examined
348 with the analysis program gprof(1). The -p option must be given
349 both at compile-time and at link-time. Linking object files not
350 compiled with -p is possible, but results in less precise pro‐
351 filing.
352 See the gprof(1) man page for more information about the pro‐
354 files.
355 Full support for gprof(1) is only available for certain plat‐
357 forms (currently: Intel x86/Linux and Alpha/Digital Unix). On
358 other platforms, the -p option will result in a less precise
359 profile (no call graph information, only a time profile).
360 -pack Build an object file (.cmx and .o files) and its associated com‐
362 piled interface (.cmi) that combines the .cmx object files given
363 on the command line, making them appear as sub-modules of the
364 output .cmx file. The name of the output .cmx file must be
365 given with the -o option. For instance, ocam‐
366 lopt -pack -o P.cmx A.cmx B.cmx C.cmx generates compiled files
367 P.cmx, P.o and P.cmi describing a compilation unit having three
368 sub-modules A, B and C, corresponding to the contents of the
369 object files A.cmx, B.cmx and C.cmx. These contents can be ref‐
370 erenced as P.A, P.B and P.C in the remainder of the program.
371 The .cmx object files being combined must have been compiled
373 with the appropriate -for-pack option. In the example above,
374 A.cmx, B.cmx and C.cmx must have been compiled with ocam‐
375 lopt -for-pack P.
376 Multiple levels of packing can be achieved by combining -pack
378 with -for-pack. See The OCaml user's manual, chapter "Native-
379 code compilation" for more details.
380 -plugin plugin
382 Dynamically load the code of the given plugin (a .cmo, .cma or
383 .cmxs file) in the compiler. The plugin must exist in the same
384 kind of code as the compiler (ocamlopt.byte must load bytecode
385 plugins, while ocamlopt.opt must load native code plugins), and
386 extension adaptation is done automatically for .cma files (to
387 .cmxs files if the compiler is compiled in native code).
388 -pp command
390 Cause the compiler to call the given command as a preprocessor
391 for each source file. The output of command is redirected to an
392 intermediate file, which is compiled. If there are no compila‐
393 tion errors, the intermediate file is deleted afterwards.
394 -ppx command
396 After parsing, pipe the abstract syntax tree through the pre‐
397 processor command. The module Ast_mapper(3) implements the
398 external interface of a preprocessor.
399 -principal
401 Check information path during type-checking, to make sure that
402 all types are derived in a principal way. All programs accepted
403 in -principal mode are also accepted in default mode with equiv‐
404 alent types, but different binary signatures.
405 -rectypes
407 Allow arbitrary recursive types during type-checking. By
408 default, only recursive types where the recursion goes through
409 an object type are supported. Note that once you have created an
410 interface using this flag, you must use it again for all depen‐
411 dencies.
412 -runtime-variant suffix
414 Add suffix to the name of the runtime library that will be used
415 by the program. If OCaml was configured with option
416 -with-debug-runtime, then the d suffix is supported and gives a
417 debug version of the runtime.
418 -S Keep the assembly code produced during the compilation. The
420 assembly code for the source file x.ml is saved in the file x.s.
421 -stop-after pass
423 Stop compilation after the given compilation pass. The currently
424 supported passes are: parsing, typing.
425 -safe-string
427 Enforce the separation between types string and bytes, thereby
428 making strings read-only. This is the default.
429 -shared
431 Build a plugin (usually .cmxs) that can be dynamically loaded
432 with the Dynlink module. The name of the plugin must be set with
433 the -o option. A plugin can include a number of OCaml modules
434 and libraries, and extra native objects (.o, .a files). Build‐
435 ing native plugins is only supported for some operating system.
436 Under some systems (currently, only Linux AMD 64), all the OCaml
437 code linked in a plugin must have been compiled without the
438 -nodynlink flag. Some constraints might also apply to the way
439 the extra native objects have been compiled (under Linux AMD 64,
440 they must contain only position-independent code).
441 -short-paths
443 When a type is visible under several module-paths, use the
444 shortest one when printing the type's name in inferred inter‐
445 faces and error and warning messages.
446 -strict-sequence
448 The left-hand part of a sequence must have type unit.
449 -unboxed-types
451 When a type is unboxable (i.e. a record with a single argument
452 or a concrete datatype with a single constructor of one argu‐
453 ment) it will be unboxed unless annotated with [@@ocaml.boxed].
454 -no-unboxed-types
456 When a type is unboxable it will be boxed unless annotated with
457 [@@ocaml.unboxed]. This is the default.
458 -unsafe
460 Turn bound checking off for array and string accesses (the
461 v.(i)ands.[i] constructs). Programs compiled with -unsafe are
462 therefore faster, but unsafe: anything can happen if the program
463 accesses an array or string outside of its bounds. Additionally,
464 turn off the check for zero divisor in integer division and mod‐
465 ulus operations. With -unsafe, an integer division (or modulus)
466 by zero can halt the program or continue with an unspecified
467 result instead of raising a Division_by_zero exception.
468 -unsafe-string
470 Identify the types string and bytes, thereby making strings
471 writable. This is intended for compatibility with old source
472 code and should not be used with new software.
473 -v Print the version number of the compiler and the location of the
475 standard library directory, then exit.
476 -verbose
478 Print all external commands before they are executed, in partic‐
479 ular invocations of the assembler, C compiler, and linker.
480 -version or -vnum
482 Print the version number of the compiler in short form (e.g.
483 "3.11.0"), then exit.
484 -w warning-list
486 Enable, disable, or mark as fatal the warnings specified by the
487 argument warning-list. See ocamlc(1) for the syntax of warning-
488 list.
489 -warn-error warning-list
491 Mark as fatal the warnings specified in the argument warn‐
492 ing-list. The compiler will stop with an error when one of
493 these warnings is emitted. The warning-list has the same mean‐
494 ing as for the -w option: a + sign (or an uppercase letter)
495 marks the corresponding warnings as fatal, a - sign (or a lower‐
496 case letter) turns them back into non-fatal warnings, and a @
497 sign both enables and marks as fatal the corresponding warnings.
498 Note: it is not recommended to use the -warn-error option in
500 production code, because it will almost certainly prevent com‐
501 piling your program with later versions of OCaml when they add
502 new warnings or modify existing warnings.
503 The default setting is -warn-error -a+31 (only warning 31 is
505 fatal).
506 -warn-help
508 Show the description of all available warning numbers.
509 -where Print the location of the standard library, then exit.
511 - file Process file as a file name, even if it starts with a dash (-)
513 character.
514 -help or --help
516 Display a short usage summary and exit.
517
520 The IA32 code generator (Intel Pentium, AMD Athlon) supports the fol‐
521 lowing additional option:
522 -ffast-math
524 Use the IA32 instructions to compute trigonometric and exponen‐
525 tial functions, instead of calling the corresponding library
526 routines. The functions affected are: atan, atan2, cos, log,
527 log10, sin, sqrt and tan. The resulting code runs faster, but
528 the range of supported arguments and the precision of the result
529 can be reduced. In particular, trigonometric operations cos,
530 sin, tan have their range reduced to [-2^64, 2^64].
531
534 The AMD64 code generator (64-bit versions of Intel Pentium and AMD
535 Athlon) supports the following additional options:
536 -fPIC Generate position-independent machine code. This is the
538 default.
539 -fno-PIC
541 Generate position-dependent machine code.
542
545 The ARM code generator supports the following additional options:
546 -farch=armv4|armv5|armv5te|armv6|armv6t2|armv7
548 Select the ARM target architecture
549 -ffpu=soft|vfpv2|vfpv3-d16|vfpv3
551 Select the floating-point hardware
552 -fPIC Generate position-independent machine code.
554 -fno-PIC
556 Generate position-dependent machine code. This is the default.
557 -fthumb
559 Enable Thumb/Thumb-2 code generation
560 -fno-thumb
562 Disable Thumb/Thumb-2 code generation
563 The default values for target architecture, floating-point hardware and
565 thumb usage were selected at configure-time when building ocamlopt
566 itself. This configuration can be inspected using ocamlopt -config.
567 Target architecture depends on the "model" setting, while floating-
568 point hardware and thumb support are determined from the ABI setting in
569 "system" ( linux_eabiorlinux_eabihf).
570
573 ocamlc(1).
574 The OCaml user's manual, chapter "Native-code compilation".
575 OCAMLOPT(1)