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llc - LLVM static compiler llc - LLVM static compiler
========================== ==========================
SYNOPSIS SYNOPSIS
-------- --------
:program:`llc` [*options*] [*filename*]
**llc** [*options*] [*filename*]
DESCRIPTION DESCRIPTION
----------- -----------
The :program:`llc` command compiles LLVM source inputs into assembly language
The **llc** command compiles LLVM source inputs into assembly language for a for a specified architecture. The assembly language output can then be passed
specified architecture. The assembly language output can then be passed through through a native assembler and linker to generate a native executable.
a native assembler and linker to generate a native executable.
The choice of architecture for the output assembly code is automatically The choice of architecture for the output assembly code is automatically
determined from the input file, unless the **-march** option is used to override determined from the input file, unless the :option:`-march` option is used to
the default. override the default.
OPTIONS OPTIONS
------- -------
If ``filename`` is "``-``" or omitted, :program:`llc` reads from standard input.
Otherwise, it will from ``filename``. Inputs can be in either the LLVM assembly
language format (``.ll``) or the LLVM bitcode format (``.bc``).
If *filename* is - or omitted, **llc** reads from standard input. Otherwise, it If the :option:`-o` option is omitted, then :program:`llc` will send its output
will from *filename*. Inputs can be in either the LLVM assembly language to standard output if the input is from standard input. If the :option:`-o`
format (.ll) or the LLVM bitcode format (.bc). option specifies "``-``", then the output will also be sent to standard output.
If the **-o** option is omitted, then **llc** will send its output to standard If no :option:`-o` option is specified and an input file other than "``-``" is
output if the input is from standard input. If the **-o** option specifies -, specified, then :program:`llc` creates the output filename by taking the input
then the output will also be sent to standard output. filename, removing any existing ``.bc`` extension, and adding a ``.s`` suffix.
If no **-o** option is specified and an input file other than - is specified, Other :program:`llc` options are described below.
then **llc** creates the output filename by taking the input filename,
removing any existing *.bc* extension, and adding a *.s* suffix.
Other **llc** options are as follows:
End-user Options End-user Options
~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~
.. option:: -help
**-help**
Print a summary of command line options. Print a summary of command line options.
.. option:: -O=uint
Generate code at different optimization levels. These correspond to the
``-O0``, ``-O1``, ``-O2``, and ``-O3`` optimization levels used by
:program:`llvm-gcc` and :program:`clang`.
**-O**\ =\ *uint* .. option:: -mtriple=<target triple>
Generate code at different optimization levels. These correspond to the *-O0*,
*-O1*, *-O2*, and *-O3* optimization levels used by **llvm-gcc** and
**clang**.
**-mtriple**\ =\ *target triple*
Override the target triple specified in the input file with the specified Override the target triple specified in the input file with the specified
string. string.
.. option:: -march=<arch>
**-march**\ =\ *arch*
Specify the architecture for which to generate assembly, overriding the target Specify the architecture for which to generate assembly, overriding the target
encoded in the input file. See the output of **llc -help** for a list of encoded in the input file. See the output of ``llc -help`` for a list of
valid architectures. By default this is inferred from the target triple or valid architectures. By default this is inferred from the target triple or
autodetected to the current architecture. autodetected to the current architecture.
.. option:: -mcpu=<cpuname>
**-mcpu**\ =\ *cpuname*
Specify a specific chip in the current architecture to generate code for. Specify a specific chip in the current architecture to generate code for.
By default this is inferred from the target triple and autodetected to By default this is inferred from the target triple and autodetected to
the current architecture. For a list of available CPUs, use: the current architecture. For a list of available CPUs, use:
**llvm-as < /dev/null | llc -march=xyz -mcpu=help**
.. code-block:: none
llvm-as < /dev/null | llc -march=xyz -mcpu=help
**-mattr**\ =\ *a1,+a2,-a3,...* .. option:: -mattr=a1,+a2,-a3,...
Override or control specific attributes of the target, such as whether SIMD Override or control specific attributes of the target, such as whether SIMD
operations are enabled or not. The default set of attributes is set by the operations are enabled or not. The default set of attributes is set by the
current CPU. For a list of available attributes, use: current CPU. For a list of available attributes, use:
**llvm-as < /dev/null | llc -march=xyz -mattr=help**
.. code-block:: none
llvm-as < /dev/null | llc -march=xyz -mattr=help
**--disable-fp-elim** .. option:: --disable-fp-elim
Disable frame pointer elimination optimization. Disable frame pointer elimination optimization.
.. option:: --disable-excess-fp-precision
**--disable-excess-fp-precision**
Disable optimizations that may produce excess precision for floating point. Disable optimizations that may produce excess precision for floating point.
Note that this option can dramatically slow down code on some systems Note that this option can dramatically slow down code on some systems
(e.g. X86). (e.g. X86).
.. option:: --enable-no-infs-fp-math
**--enable-no-infs-fp-math**
Enable optimizations that assume no Inf values. Enable optimizations that assume no Inf values.
.. option:: --enable-no-nans-fp-math
**--enable-no-nans-fp-math**
Enable optimizations that assume no NAN values. Enable optimizations that assume no NAN values.
.. option:: --enable-unsafe-fp-math
**--enable-unsafe-fp-math**
Enable optimizations that make unsafe assumptions about IEEE math (e.g. that Enable optimizations that make unsafe assumptions about IEEE math (e.g. that
addition is associative) or may not work for all input ranges. These addition is associative) or may not work for all input ranges. These
optimizations allow the code generator to make use of some instructions which optimizations allow the code generator to make use of some instructions which
would otherwise not be usable (such as fsin on X86). would otherwise not be usable (such as ``fsin`` on X86).
.. option:: --enable-correct-eh-support
Instruct the **lowerinvoke** pass to insert code for correct exception
handling support. This is expensive and is by default omitted for efficiency.
**--enable-correct-eh-support** .. option:: --stats
Instruct the **lowerinvoke** pass to insert code for correct exception handling
support. This is expensive and is by default omitted for efficiency.
**--stats**
Print statistics recorded by code-generation passes. Print statistics recorded by code-generation passes.
.. option:: --time-passes
**--time-passes**
Record the amount of time needed for each pass and print a report to standard Record the amount of time needed for each pass and print a report to standard
error. error.
.. option:: --load=<dso_path>
Dynamically load ``dso_path`` (a path to a dynamically shared object) that
**--load**\ =\ *dso_path* implements an LLVM target. This will permit the target name to be used with
the :option:`-march` option so that code can be generated for that target.
Dynamically load *dso_path* (a path to a dynamically shared object) that
implements an LLVM target. This will permit the target name to be used with the
**-march** option so that code can be generated for that target.
Tuning/Configuration Options Tuning/Configuration Options
~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. option:: --print-machineinstrs
**--print-machineinstrs**
Print generated machine code between compilation phases (useful for debugging). Print generated machine code between compilation phases (useful for debugging).
.. option:: --regalloc=<allocator>
Specify the register allocator to use. The default ``allocator`` is *local*.
**--regalloc**\ =\ *allocator*
Specify the register allocator to use. The default *allocator* is *local*.
Valid register allocators are: Valid register allocators are:
*simple* *simple*
Very simple "always spill" register allocator Very simple "always spill" register allocator
*local* *local*
Local register allocator Local register allocator
*linearscan* *linearscan*
Linear scan global register allocator Linear scan global register allocator
*iterativescan* *iterativescan*
Iterative scan global register allocator Iterative scan global register allocator
.. option:: --spiller=<spiller>
**--spiller**\ =\ *spiller*
Specify the spiller to use for register allocators that support it. Currently Specify the spiller to use for register allocators that support it. Currently
this option is used only by the linear scan register allocator. The default this option is used only by the linear scan register allocator. The default
*spiller* is *local*. Valid spillers are: ``spiller`` is *local*. Valid spillers are:
*simple* *simple*
Simple spiller Simple spiller
*local* *local*
Local spiller Local spiller
Intel IA-32-specific Options Intel IA-32-specific Options
~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. option:: --x86-asm-syntax=[att|intel]
Specify whether to emit assembly code in AT&T syntax (the default) or Intel
**--x86-asm-syntax=att|intel**
Specify whether to emit assembly code in AT&T syntax (the default) or intel
syntax. syntax.
EXIT STATUS EXIT STATUS
----------- -----------
If :program:`llc` succeeds, it will exit with 0. Otherwise, if an error
If **llc** succeeds, it will exit with 0. Otherwise, if an error occurs, occurs, it will exit with a non-zero value.
it will exit with a non-zero value.
SEE ALSO SEE ALSO
-------- --------
lli
lli|lli