path: root/docs/CommandGuide/lli.rst

lli - directly execute programs from LLVM bitcode
=================================================


SYNOPSIS
--------


**lli** [*options*] [*filename*] [*program args*]


DESCRIPTION
-----------


**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, if one is
available for the current architecture, or an interpreter.  **lli** takes all of
the same code generator options as llc|llc, but they are only effective when
**lli** is using the just-in-time compiler.

If *filename* is not specified, then **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
---------------



**-fake-argv0**\ =\ *executable*

 Override the ``argv[0]`` value passed into the executing program.



**-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.



**-help**

 Print a summary of command line options.



**-load**\ =\ *pluginfilename*

 Causes **lli** to load the plugin (shared object) named *pluginfilename* and use
 it for optimization.



**-stats**

 Print statistics from the code-generation passes. This is only meaningful for
 the just-in-time compiler, at present.



**-time-passes**

 Record the amount of time needed for each code-generation pass and print it to
 standard error.



**-version**

 Print out the version of **lli** and exit without doing anything else.




TARGET OPTIONS
--------------



**-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.



**-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.



**-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**



**-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
----------------------



**-disable-excess-fp-precision**

 Disable optimizations that may increase floating point precision.



**-enable-no-infs-fp-math**

 Enable optimizations that assume no Inf values.



**-enable-no-nans-fp-math**

 Enable optimizations that assume no NAN values.



**-enable-unsafe-fp-math**

 Causes **lli** to enable optimizations that may decrease floating point
 precision.



**-soft-float**

 Causes **lli** to generate software floating point library calls instead of
 equivalent hardware instructions.




CODE GENERATION OPTIONS
-----------------------



**-code-model**\ =\ *model*

 Choose the code model from:


 .. code-block:: perl

      default: Target default code model
      small: Small code model
      kernel: Kernel code model
      medium: Medium code model
      large: Large code model




**-disable-post-RA-scheduler**

 Disable scheduling after register allocation.



**-disable-spill-fusing**

 Disable fusing of spill code into instructions.



**-jit-enable-eh**

 Exception handling should be enabled in the just-in-time compiler.



**-join-liveintervals**

 Coalesce copies (default=true).



**-nozero-initialized-in-bss** Don't place zero-initialized symbols into the BSS section.



**-pre-RA-sched**\ =\ *scheduler*

 Instruction schedulers available (before register allocation):


 .. code-block:: perl

      =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




**-regalloc**\ =\ *allocator*

 Register allocator to use (default=linearscan)


 .. code-block:: perl

      =bigblock: Big-block register allocator
      =linearscan: linear scan register allocator =local -   local register allocator
      =simple: simple register allocator




**-relocation-model**\ =\ *model*

 Choose relocation model from:


 .. code-block:: perl

      =default: Target default relocation model
      =static: Non-relocatable code =pic -   Fully relocatable, position independent code
      =dynamic-no-pic: Relocatable external references, non-relocatable code




**-spiller**

 Spiller to use (default=local)


 .. code-block:: perl

      =simple: simple spiller
      =local: local spiller




**-x86-asm-syntax**\ =\ *syntax*

 Choose style of code to emit from X86 backend:


 .. code-block:: perl

      =att: Emit AT&T-style assembly
      =intel: Emit Intel-style assembly





EXIT STATUS
-----------


If **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
--------


llc|llc