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 default setting is auto, and the current heuristic checks
140 that the "TERM" environment variable exists and is not empty or
141 "dumb", and that isatty(stderr) holds.
142 The environment variable "OCAML_COLOR" is considered if -color
144 is not provided. Its values are auto/always/never as above.
145 -error-style mode
148 Control the way error messages and warnings are printed. The
149 following modes are supported:
150 short only print the error and its location;
152 contextual like "short", but also display the source code snip‐
154 pet corresponding to the location of the error.
155 The default setting is contextual.
157 The environment variable "OCAML_ERROR_STYLE" is considered if
159 -error-style is not provided. Its values are short/contextual as
160 above.
161 -compact
164 Optimize the produced code for space rather than for time. This
165 results in smaller but slightly slower programs. The default is
166 to optimize for speed.
167 -config
169 Print the version number of ocamlopt(1) and a detailed summary
170 of its configuration, then exit.
171 -config-var
173 Print the value of a specific configuration variable from the
174 -config output, then exit. If the variable does not exist, the
175 exit code is non-zero.
176 -depend ocamldep-args
178 Compute dependencies, as ocamldep would do.
179 -for-pack module-path
181 Generate an object file (.cmx and .o files) that can later be
182 included as a sub-module (with the given access path) of a com‐
183 pilation unit constructed with -pack. For instance, ocam‐
184 lopt -for-pack P -c A.ml will generate a.cmx and a.o files that
185 can later be used with ocamlopt -pack -o P.cmx a.cmx.
186 -g Add debugging information while compiling and linking. This op‐
188 tion is required in order to produce stack backtraces when the
189 program terminates on an uncaught exception (see ocamlrun(1)).
190 -i Cause the compiler to print all defined names (with their in‐
192 ferred types or their definitions) when compiling an implementa‐
193 tion (.ml file). No compiled files (.cmo and .cmi files) are
194 produced. This can be useful to check the types inferred by the
195 compiler. Also, since the output follows the syntax of inter‐
196 faces, it can help in writing an explicit interface (.mli file)
197 for a file: just redirect the standard output of the compiler to
198 a .mli file, and edit that file to remove all declarations of
199 unexported names.
200 -I directory
202 Add the given directory to the list of directories searched for
203 compiled interface files (.cmi), compiled object code files
204 (.cmx), and libraries (.cmxa). By default, the current directory
205 is searched first, then the standard library directory. Directo‐
206 ries added with -I are searched after the current directory, in
207 the order in which they were given on the command line, but be‐
208 fore the standard library directory. See also option -nostdlib.
209 If the given directory starts with +, it is taken relative to
211 the standard library directory. For instance, -I +compiler-libs
212 adds the subdirectory compiler-libs of the standard library to
213 the search path.
214 -impl filename
216 Compile the file filename as an implementation file, even if its
217 extension is not .ml.
218 -inline n
220 Set aggressiveness of inlining to n, where n is a positive inte‐
221 ger. Specifying -inline 0 prevents all functions from being in‐
222 lined, except those whose body is smaller than the call site.
223 Thus, inlining causes no expansion in code size. The default ag‐
224 gressiveness, -inline 1, allows slightly larger functions to be
225 inlined, resulting in a slight expansion in code size. Higher
226 values for the -inline option cause larger and larger functions
227 to become candidate for inlining, but can result in a serious
228 increase in code size.
229 -insn-sched
231 Enables the instruction scheduling pass in the compiler backend.
232 -intf filename
234 Compile the file filename as an interface file, even if its ex‐
235 tension is not .mli.
236 -intf-suffix string
238 Recognize file names ending with string as interface files (in‐
239 stead of the default .mli).
240 -keep-docs
242 Keep documentation strings in generated .cmi files.
243 -keep-locs
245 Keep locations in generated .cmi files.
246 -labels
248 Labels are not ignored in types, labels may be used in applica‐
249 tions, and labelled parameters can be given in any order. This
250 is the default.
251 -linkall
253 Force all modules contained in libraries to be linked in. If
254 this flag is not given, unreferenced modules are not linked in.
255 When building a library (-a flag), setting the -linkall flag
256 forces all subsequent links of programs involving that library
257 to link all the modules contained in the library. When compil‐
258 ing a module (option -c), setting the -linkall option ensures
259 that this module will always be linked if it is put in a library
260 and this library is linked.
261 -linscan
263 Use linear scan register allocation. Compiling with this allo‐
264 cator is faster than with the usual graph coloring allocator,
265 sometimes quite drastically so for long functions and modules.
266 On the other hand, the generated code can be a bit slower.
267 -match-context-rows
269 Set number of rows of context used during pattern matching com‐
270 pilation. Lower values cause faster compilation, but less opti‐
271 mized code. The default value is 32.
272 -no-alias-deps
274 Do not record dependencies for module aliases.
275 -no-app-funct
277 Deactivates the applicative behaviour of functors. With this op‐
278 tion, each functor application generates new types in its result
279 and applying the same functor twice to the same argument yields
280 two incompatible structures.
281 -noassert
283 Do not compile assertion checks. Note that the special form as‐
284 sert false is always compiled because it is typed specially.
285 This flag has no effect when linking already-compiled files.
286 -noautolink
288 When linking .cmxa libraries, ignore -cclib and -ccopt options
289 potentially contained in the libraries (if these options were
290 given when building the libraries). This can be useful if a li‐
291 brary contains incorrect specifications of C libraries or C op‐
292 tions; in this case, during linking, set -noautolink and pass
293 the correct C libraries and options on the command line.
294 -nodynlink
296 Allow the compiler to use some optimizations that are valid only
297 for code that is never dynlinked.
298 -no-insn-sched
300 Disables the instruction scheduling pass in the compiler back‐
301 end.
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 im‐
322 plementation 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 -output-complete-obj Same as -output-obj except the object file
346 produced includes the runtime and autolink libraries.
347 -pack Build an object file (.cmx and .o files) and its associated com‐
350 piled interface (.cmi) that combines the .cmx object files given
351 on the command line, making them appear as sub-modules of the
352 output .cmx file. The name of the output .cmx file must be
353 given with the -o option. For instance, ocam‐
354 lopt -pack -o P.cmx A.cmx B.cmx C.cmx generates compiled files
355 P.cmx, P.o and P.cmi describing a compilation unit having three
356 sub-modules A, B and C, corresponding to the contents of the ob‐
357 ject files A.cmx, B.cmx and C.cmx. These contents can be refer‐
358 enced as P.A, P.B and P.C in the remainder of the program.
359 The .cmx object files being combined must have been compiled
361 with the appropriate -for-pack option. In the example above,
362 A.cmx, B.cmx and C.cmx must have been compiled with ocam‐
363 lopt -for-pack P.
364 Multiple levels of packing can be achieved by combining -pack
366 with -for-pack. See The OCaml user's manual, chapter "Native-
367 code compilation" for more details.
368 -pp command
370 Cause the compiler to call the given command as a preprocessor
371 for each source file. The output of command is redirected to an
372 intermediate file, which is compiled. If there are no compila‐
373 tion errors, the intermediate file is deleted afterwards.
374 -ppx command
376 After parsing, pipe the abstract syntax tree through the pre‐
377 processor command. The module Ast_mapper(3) implements the ex‐
378 ternal interface of a preprocessor.
379 -principal
381 Check information path during type-checking, to make sure that
382 all types are derived in a principal way. All programs accepted
383 in -principal mode are also accepted in default mode with equiv‐
384 alent types, but different binary signatures.
385 -rectypes
387 Allow arbitrary recursive types during type-checking. By de‐
388 fault, only recursive types where the recursion goes through an
389 object type are supported. Note that once you have created an
390 interface using this flag, you must use it again for all depen‐
391 dencies.
392 -runtime-variant suffix
394 Add suffix to the name of the runtime library that will be used
395 by the program. If OCaml was configured with option -with-de‐
396 bug-runtime, then the d suffix is supported and gives a debug
397 version of the runtime.
398 -S Keep the assembly code produced during the compilation. The as‐
400 sembly code for the source file x.ml is saved in the file x.s.
401 -stop-after pass
403 Stop compilation after the given compilation pass. The currently
404 supported passes are: parsing, typing, scheduling, emit.
405 -save-ir-after pass
407 Save intermediate representation after the given compilation
408 pass. The currently supported passes are: scheduling.
409 -safe-string
411 Enforce the separation between types string and bytes, thereby
412 making strings read-only. This is the default.
413 -shared
415 Build a plugin (usually .cmxs) that can be dynamically loaded
416 with the Dynlink module. The name of the plugin must be set with
417 the -o option. A plugin can include a number of OCaml modules
418 and libraries, and extra native objects (.o, .a files). Build‐
419 ing native plugins is only supported for some operating system.
420 Under some systems (currently, only Linux AMD 64), all the OCaml
421 code linked in a plugin must have been compiled without the -no‐
422 dynlink flag. Some constraints might also apply to the way the
423 extra native objects have been compiled (under Linux AMD 64,
424 they must contain only position-independent code).
425 -short-paths
427 When a type is visible under several module-paths, use the
428 shortest one when printing the type's name in inferred inter‐
429 faces and error and warning messages.
430 -strict-sequence
432 The left-hand part of a sequence must have type unit.
433 -unboxed-types
435 When a type is unboxable (i.e. a record with a single argument
436 or a concrete datatype with a single constructor of one argu‐
437 ment) it will be unboxed unless annotated with [@@ocaml.boxed].
438 -no-unboxed-types
440 When a type is unboxable it will be boxed unless annotated with
441 [@@ocaml.unboxed]. This is the default.
442 -unsafe
444 Turn bound checking off for array and string accesses (the
445 v.(i)ands.[i] constructs). Programs compiled with -unsafe are
446 therefore faster, but unsafe: anything can happen if the program
447 accesses an array or string outside of its bounds. Additionally,
448 turn off the check for zero divisor in integer division and mod‐
449 ulus operations. With -unsafe, an integer division (or modulus)
450 by zero can halt the program or continue with an unspecified re‐
451 sult instead of raising a Division_by_zero exception.
452 -unsafe-string
454 Identify the types string and bytes, thereby making strings
455 writable. This is intended for compatibility with old source
456 code and should not be used with new software.
457 -v Print the version number of the compiler and the location of the
459 standard library directory, then exit.
460 -verbose
462 Print all external commands before they are executed, in partic‐
463 ular invocations of the assembler, C compiler, and linker.
464 -version or -vnum
466 Print the version number of the compiler in short form (e.g.
467 "3.11.0"), then exit.
468 -w warning-list
470 Enable, disable, or mark as fatal the warnings specified by the
471 argument warning-list. See ocamlc(1) for the syntax of warning-
472 list.
473 -warn-error warning-list
475 Mark as fatal the warnings specified in the argument warn‐
476 ing-list. The compiler will stop with an error when one of
477 these warnings is emitted. The warning-list has the same mean‐
478 ing as for the -w option: a + sign (or an uppercase letter)
479 marks the corresponding warnings as fatal, a - sign (or a lower‐
480 case letter) turns them back into non-fatal warnings, and a @
481 sign both enables and marks as fatal the corresponding warnings.
482 Note: it is not recommended to use the -warn-error option in
484 production code, because it will almost certainly prevent com‐
485 piling your program with later versions of OCaml when they add
486 new warnings or modify existing warnings.
487 The default setting is -warn-error -a+31 (only warning 31 is fa‐
489 tal).
490 -warn-help
492 Show the description of all available warning numbers.
493 -where Print the location of the standard library, then exit.
495 -with-runtime
497 Include the runtime system in the generated program. This is the
498 default.
499 -without-runtime
501 The compiler does not include the runtime system (nor a refer‐
502 ence to it) in the generated program; it must be supplied sepa‐
503 rately.
504 - file Process file as a file name, even if it starts with a dash (-)
506 character.
507 -help or --help
509 Display a short usage summary and exit.
510
513 The IA32 code generator (Intel Pentium, AMD Athlon) supports the fol‐
514 lowing additional option:
515 -ffast-math
517 Use the IA32 instructions to compute trigonometric and exponen‐
518 tial functions, instead of calling the corresponding library
519 routines. The functions affected are: atan, atan2, cos, log,
520 log10, sin, sqrt and tan. The resulting code runs faster, but
521 the range of supported arguments and the precision of the result
522 can be reduced. In particular, trigonometric operations cos,
523 sin, tan have their range reduced to [-2^64, 2^64].
524
527 The AMD64 code generator (64-bit versions of Intel Pentium and AMD
528 Athlon) supports the following additional options:
529 -fPIC Generate position-independent machine code. This is the de‐
531 fault.
532 -fno-PIC
534 Generate position-dependent machine code.
535
538 The PowerPC code generator supports the following additional options:
539 -flarge-toc
541 Enables the PowerPC large model allowing the TOC (table of con‐
542 tents) to be arbitrarily large. This is the default since 4.11.
543 -fsmall-toc
545 Enables the PowerPC small model allowing the TOC to be up to 64
546 kbytes per compilation unit. Prior to 4.11 this was the default
547 behaviour. \nd{options}
548
551 The ARM code generator supports the following additional options:
552 -farch=armv4|armv5|armv5te|armv6|armv6t2|armv7
554 Select the ARM target architecture
555 -ffpu=soft|vfpv2|vfpv3-d16|vfpv3
557 Select the floating-point hardware
558 -fPIC Generate position-independent machine code.
560 -fno-PIC
562 Generate position-dependent machine code. This is the default.
563 -fthumb
565 Enable Thumb/Thumb-2 code generation
566 -fno-thumb
568 Disable Thumb/Thumb-2 code generation
569 The default values for target architecture, floating-point hardware and
571 thumb usage were selected at configure-time when building ocamlopt it‐
572 self. This configuration can be inspected using ocamlopt -config. Tar‐
573 get architecture depends on the "model" setting, while floating-point
574 hardware and thumb support are determined from the ABI setting in "sys‐
575 tem" ( linux_eabiorlinux_eabihf).
576
579 ocamlc(1).
580 The OCaml user's manual, chapter "Native-code compilation".
581 OCAMLOPT(1)