llvm-project/llvm/docs/CommandGuide/lli.rst

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lli - directly execute programs from LLVM bitcode
=================================================
SYNOPSIS
--------
:program:`lli` [*options*] [*filename*] [*program args*]
DESCRIPTION
-----------
:program:`lli` directly executes programs in LLVM bitcode format. It takes a program
in LLVM bitcode format and executes it using a just-in-time compiler or an
interpreter.
:program:`lli` is *not* an emulator. It will not execute IR of different architectures
and it can only interpret (or JIT-compile) for the host architecture.
The JIT compiler takes the same arguments as other tools, like :program:`llc`,
but they don't necessarily work for the interpreter.
If `filename` is not specified, then :program:`lli` reads the LLVM bitcode for the
program from standard input.
The optional *args* specified on the command line are passed to the program as
arguments.
GENERAL OPTIONS
---------------
.. option:: -fake-argv0=executable
Override the ``argv[0]`` value passed into the executing program.
.. option:: -force-interpreter={false,true}
If set to true, use the interpreter even if a just-in-time compiler is available
for this architecture. Defaults to false.
.. option:: -help
Print a summary of command line options.
.. option:: -load=pluginfilename
Causes :program:`lli` to load the plugin (shared object) named *pluginfilename* and use
it for optimization.
.. option:: -stats
Print statistics from the code-generation passes. This is only meaningful for
the just-in-time compiler, at present.
.. option:: -time-passes
Record the amount of time needed for each code-generation pass and print it to
standard error.
.. option:: -version
Print out the version of :program:`lli` and exit without doing anything else.
TARGET OPTIONS
--------------
.. option:: -mtriple=target triple
Override the target triple specified in the input bitcode file with the
specified string. This may result in a crash if you pick an
architecture which is not compatible with the current system.
.. option:: -march=arch
Specify the architecture for which to generate assembly, overriding the target
encoded in the bitcode file. See the output of **llc -help** for a list of
valid architectures. By default this is inferred from the target triple or
autodetected to the current architecture.
.. option:: -mcpu=cpuname
Specify a specific chip in the current architecture to generate code for.
By default this is inferred from the target triple and autodetected to
the current architecture. For a list of available CPUs, use:
**llvm-as < /dev/null | llc -march=xyz -mcpu=help**
.. option:: -mattr=a1,+a2,-a3,...
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
current CPU. For a list of available attributes, use:
**llvm-as < /dev/null | llc -march=xyz -mattr=help**
FLOATING POINT OPTIONS
----------------------
.. option:: -disable-excess-fp-precision
Disable optimizations that may increase floating point precision.
.. option:: -enable-no-infs-fp-math
Enable optimizations that assume no Inf values.
.. option:: -enable-no-nans-fp-math
Enable optimizations that assume no NAN values.
.. option:: -enable-unsafe-fp-math
Causes :program:`lli` to enable optimizations that may decrease floating point
precision.
.. option:: -soft-float
Causes :program:`lli` to generate software floating point library calls instead of
equivalent hardware instructions.
CODE GENERATION OPTIONS
-----------------------
.. option:: -code-model=model
Choose the code model from:
.. code-block:: text
default: Target default code model
small: Small code model
kernel: Kernel code model
medium: Medium code model
large: Large code model
.. option:: -disable-post-RA-scheduler
Disable scheduling after register allocation.
.. option:: -disable-spill-fusing
Disable fusing of spill code into instructions.
.. option:: -jit-enable-eh
Exception handling should be enabled in the just-in-time compiler.
.. option:: -join-liveintervals
Coalesce copies (default=true).
.. option:: -nozero-initialized-in-bss
Don't place zero-initialized symbols into the BSS section.
.. option:: -pre-RA-sched=scheduler
Instruction schedulers available (before register allocation):
.. code-block:: text
=default: Best scheduler for the target
=none: No scheduling: breadth first sequencing
=simple: Simple two pass scheduling: minimize critical path and maximize processor utilization
=simple-noitin: Simple two pass scheduling: Same as simple except using generic latency
=list-burr: Bottom-up register reduction list scheduling
=list-tdrr: Top-down register reduction list scheduling
=list-td: Top-down list scheduler -print-machineinstrs - Print generated machine code
.. option:: -regalloc=allocator
Register allocator to use (default=linearscan)
.. code-block:: text
=bigblock: Big-block register allocator
=linearscan: linear scan register allocator =local - local register allocator
=simple: simple register allocator
.. option:: -relocation-model=model
Choose relocation model from:
.. code-block:: text
=default: Target default relocation model
=static: Non-relocatable code =pic - Fully relocatable, position independent code
=dynamic-no-pic: Relocatable external references, non-relocatable code
.. option:: -spiller
Spiller to use (default=local)
.. code-block:: text
=simple: simple spiller
=local: local spiller
.. option:: -x86-asm-syntax=syntax
Choose style of code to emit from X86 backend:
.. code-block:: text
=att: Emit AT&T-style assembly
=intel: Emit Intel-style assembly
EXIT STATUS
-----------
If :program:`lli` fails to load the program, it will exit with an exit code of 1.
Otherwise, it will return the exit code of the program it executes.
SEE ALSO
--------
:program:`llc`