Provided by: mlton-compiler_20130715-3_amd64 
NAME
mlton - whole-program compiler for the Standard ML (SML) programming language
SYNOPSIS
mlton [option ...] file.{c|mlb|o|sml} [file.{c|o|s|S} ...]
DESCRIPTION
MLton is run from the command line with a collection of options followed by a file name and a list of
files with which to compile, assemble, and link with. The simplest case is to run mlton foo.sml, where
foo.sml contains a valid SML program, in which case MLton compiles the program to produce an executable
foo. Since MLton does not support separate compilation, the program must be the entire program you wish
to compile. However, the program may refer to signatures and structures defined in the Basis Library.
Larger programs, spanning many files, may be compiled with the ML Basis system. In this case, mlton
foo.mlb will compile the complete SML program described by the basis foo.mlb, which may specify both SML
files and additional bases. See the MLton Guide for details.
MLton's compile-time options control the name of the output file, the verbosity of compile-time messages,
and whether or not certain optimizations are performed. They also can specify which intermediate files
are saved and can stop the compilation process early, at some intermediate pass, in which case
compilation can be resumed by passing the generated files to MLton. MLton uses the input file suffix to
determine the type of input program. The possibilities are .c, .mlb, .o, .s, and .sml.
With no arguments, MLton prints the version number and exits. For a usage message, run MLton with an
invalid switch, e.g. mlton -z. In the explanation below and in the usage message, for flags that take a
number of choices (e.g. {true|false}), the first value listed is the default.
Compile-time options
-align n
Aligns objects in memory by the specified alignment (4 or 8). The default varies depending on
architecture.
-as-opt option
Pass option to gcc when compiling assembler code. If you wish to pass an option to the assembler,
you must use gcc's -Wa, syntax.
-cc-opt option
Pass option to gcc when compiling C code.
-codegen {native|x86|amd64|c}
Generate native code or C code. With -codegen native (-codegen x86 or -codegen amd64), MLton
typically compiles more quickly and generates better code.
-const 'name value'
Set the value of a compile-time constant. Here is a list of available constants, their default
values, and what they control.
Exn.keepHistory {false|true}
Enable MLton.Exn.history. There is a performance cost to setting this to true, both in
memory usage of exceptions and in run time, because of additional work that must be performed
at each exception construction, raise, and handle.
-default-ann ann
Specify default ML Basis annotations. For example, -default-ann 'warnUnused true' causes unused
variable warnings to be enabled by default. Defaults may be overridden by an annotation in an ML
Basis file.
-default-type type
Specify the default binding for a primitive type. For example, -default-type word64 causes the
top-level type word and the top-level structure Word in the Basis Library to be equal to
Word64.word and Word64:WORD, respectively. Similarly, -default-type intinf causes the top-level
type int and the top-level structure Int in the Basis Library to be equal to IntInf.int and
IntInf:INTEGER, respectively.
-disable-ann ann
Ignore the specified ML Basis annotation in every ML Basis File. For example, to see all match and
unused warnings, compile with -default-ann 'warnUnused true', -disable-ann forceUsed, -disable-ann
nonexhaustiveMatch, -disable-ann redundantMatch, and -disable-ann warnUnused.
-export-header file
Write C prototypes to file for all of the functions in the program exported from SML to C.
-ieee-fp {false|true}
Cause the x86 native code generator to be pedantic about following the IEEE floating point
standard. By default, it is not, because of the performance cost. This only has an effect with
-codegen x86.
-inline n
Set the inlining threshold used in the optimizer. The threshold is an approximate measure of code
size of a procedure. The default is 320.
-keep {g|o}
Save intermediate files. If no -keep argument is given, then only the output file is saved.
g generated .c and .s files passed to gcc
o object (.o) files
-link-opt option
Pass option to gcc when linking. You can use this to specify library search paths, e.g. -link-opt
-Lpath, and libraries to link with, e.g. -link-opt -lfoo, or even both at the same time, e.g.
-link-opt '-Lpath -lfoo'. If you wish to pass an option to the linker, you must use gcc's -Wl,
syntax, e.g., -link-opt '-Wl,--export-dynamic'.
-mlb-path-map file
Use file as an ML Basis path map to define additional MLB path variables. Multiple uses of
-mlb-path-map and -mlb-path-var are allowed, with variable definitions in later path maps taking
precedence over earlier ones.
-mlb-path-var 'name value'
Define an additional MLB path variable. Multiple uses of -mlb-path-map and -mlb-path-var are
allowed, with variable definitions in later path maps taking precedence over earlier ones.
-output file
Specify the name of the final output file. The default name is the input file name with its
suffix removed and an appropriate, possibly empty, suffix added.
-profile {no|alloc|count|time}
Produce an executable that gathers profiling data. When such an executable is run, it will
produce an mlmon.out file. The man page on mlprof describes how to extract information from this
file.
-profile-branch {false|true}
If true, the profiler will separately gather profiling data for each branch of a function
definition, case expression, and if expression.
-profile-stack {false|true}
If true, the profiler will gather profiling data for all functions on the stack, not just the
currently executing function.
-profile-val {false|true}
If true, the profiler will separately gather profiling data for each (expansive) val declaration.
-runtime arg
Pass argument to the runtime system via @MLton. The argument will be processed before other
@MLton command line switches. Multiple uses of -runtime are allowed, and will pass all the
arguments in order. If the same runtime switch occurs more than once, then the last setting will
take effect. There is no need to supply the leading @MLton or the trailing --; these will be
supplied automatically.
An argument to -runtime may contain spaces, which will cause the argument to be treated as a
sequence of words by the runtime. For example, the command line:
mlton -runtime 'ram-slop 0.4' foo.sml
will cause foo to run as if it had been called like
foo @MLton ram-slop 0.4 --
An executable created with -runtime stop doesn't process any @MLton arguments. This is useful to
create an executable, e.g. echo, that must treat @MLton like any other command-line argument.
% mlton -runtime stop echo.sml
% echo @MLton --
@MLton --
-show-basis file
Pretty print to file the basis defined by the input program.
-show-def-use file
Output def-use information to file. Each identifier that is defined appears on a line, followed
on subsequent lines by the position of each use.
-stop {f|g|o|tc}
Specify when to stop.
f list of files on stdout (only makes sense when input is foo.mlb)
g generated .c and .s files
o object (.o) files
tc after type checking
If you compile -stop g or -stop o, you can resume compilation by running MLton on the generated .c
and .s or .o files.
-target {self|...}
Generate an executable that runs on the specified platform. The default is self, which means to
compile for the machine that MLton is running on. To use any other target, you must first install
a cross compiler. See the MLton Guide for details.
-target-as-opt target option
Like -as-opt, this passes option to gcc when assembling, except it only passes option when the
target architecture or operating system is target.
-target-cc-opt target option
Like -cc-opt, this passes option to gcc when compiling C code, except it only passes option when
the target architecture or operating system is target.
-target-link-opt target option
Like -link-opt, this passes option to gcc when linking, except it only passes option when the
target architecture or operating system is target.
-verbose {0|1|2|3}
How verbose to be about what passes are running. The default is 0.
0 silent
1 calls to compiler, assembler, and linker
2 1, plus intermediate compiler passes
3 2, plus some data structure sizes
Runtime system options
Executables produced by MLton take command line arguments that control the runtime system. These
arguments are optional, and occur before the executable's usual arguments. To use these options, the
first argument to the executable must be @MLton. The optional arguments then follow, must be terminated
by --, and are followed by any arguments to the program. The optional arguments are not made available
to the SML program via CommandLine.arguments. For example, a valid call to hello-world is:
hello-world @MLton gc-summary fixed-heap 10k -- a b c
In the above example, CommandLine.arguments () = ["a", "b", "c"].
It is allowed to have a sequence of @MLton arguments, as in:
hello-world @MLton gc-summary -- @MLton fixed-heap 10k -- a b c
Run-time options can also control MLton, as in
mlton @MLton fixed-heap 0.5g -- foo.sml
fixed-heap x{k|K|m|M|g|G}
Use a fixed size heap of size x, where x is a real number and the trailing letter indicates its
units.
k or K 1024
m or M 1,048,576
g or G 1,073,741,824
A value of 0 means to use almost all the RAM present on the machine.
The heap size used by fixed-heap includes all memory allocated by SML code, including memory for
the stack (or stacks, if there are multiple threads). It does not, however, include any memory
used for code itself or memory used by C globals, the C stack, or malloc.
gc-messages
Print a message at the start and end of every garbage collection.
gc-summary
Print a summary of garbage collection statistics upon program termination.
load-world world
Restart the computation with the file specified by world, which must have been created by a call
to MLton.World.save by the same executable. See the MLton Guide for details.
max-heap x{k|K|m|M|g|G}
Run the computation with an automatically resized heap that is never larger than x, where x is a
real number and the trailing letter indicates the units as with fixed-heap. The heap size for
max-heap is accounted for as with fixed-heap.
may-page-heap {false|true}
Enable paging the heap to disk when unable to grow the heap to a desired size.
no-load-world
Disable load-world. This can be used as an argument to the compiler via -runtime no-load-world to
create executables that will not load a world. This may be useful to ensure that set-uid
executables do not load some strange world.
ram-slop x
Multiply x by the amount of RAM on the machine to obtain what the runtime views as the amount of
RAM it can use. Typically x is less than 1, and is used to account for space used by other
programs running on the same machine.
stop Causes the runtime to stop processing @MLton arguments once the next -- is reached. This can be
used as an argument to the compiler via -runtime stop to create executables that don't process any
@MLton arguments.
DIAGNOSTICS
MLton's type error messages are not in a form suitable for processing by Emacs. For details on how to
fix this, see http://mlton.org/Emacs.
SEE ALSO
mlprof(1) and the MLton Guide. July 15, 2013 mlton(1)