lli - directly execute programs from LLVM bitcode — LLVM 16.0.6 documentation

# 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 or an interpreter.

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 llc, but they don’t necessarily work for the interpreter.

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:

      default: Target default code model
      tiny: Tiny 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):

      =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

-regalloc=allocator

  Register allocator to use (default=linearscan)

      =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:

      =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)

      =simple: simple spiller
      =local: local spiller

-x86-asm-syntax=syntax

  Choose style of code to emit from X86 backend:

      =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(1)