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 {4|8}
Aligns object sizes and doubles in memory by the specified
alignment. The default varies depending on architecture.
-as-opt option
Pass option to gcc when assembling.
-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 and the
assembler
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. Valid values for target are: alpha, amd64,
arm,, hppa, ia64, m68k, mips, powerpc, powerpc64, s390, sparc,
x86, aix, cygwin, darwin, freebsd, hurd, hpux, linux, mingw,
netbsd, openbsd, solaris.
-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. Valid values for target are as for
-target-as-opt.
-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. Valid values for target are as for
-target-as-opt.
-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.
June 8, 2010 mlton(1)