LLI(1)

🎀 lli — the LLVM girlie who runs your bitcode 🎀

Okay bestie, so this is lli from the LLVM fam, and she is literally the main character when it comes to executing LLVM bitcode. No cap.

🌸 SYNOPSIS 🌸

lli [options] [filename] [program args]

💖 DESCRIPTION 💖

Okay so here's the tea: lli directly executes programs in LLVM bitcode format. She takes a program in LLVM bitcode format and executes it using a just-in-time compiler or an interpreter. It's giving "I run your code directly" energy.

But bestie, listen: 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. So like, don't try to run ARM code on your x86 laptop and expect it to slay, because it won't.

The JIT compiler takes the same arguments as other tools, like llc, but they don't necessarily work for the interpreter. So that's a thing to keep in mind, iykyk.

If filename is not specified, then lli reads the LLVM bitcode for the program from standard input. So you can pipe stuff in, no biggie.

The optional args specified on the command line are passed to the program as arguments. So your program gets its own little arguments to play with.

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✨ GENERAL OPTIONS ✨

• -fake-argv0=executable — Override the argv[0] value passed into the executing program. It's giving "fake it till you make it" energy.
• -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. So if you're feeling old-school, go off.
• -help — Print a summary of command line options. Classic.
• -load=pluginfilename — Causes lli to load the plugin (shared object) named pluginfilename and use it for optimization. Plugins are iconic.
• -stats — Print statistics from the code-generation passes. This is only meaningful for the just-in-time compiler, at present. So if you're using the interpreter, this is lowkey useless.
• -time-passes — Record the amount of time needed for each code-generation pass and print it to standard error. Time is precious, bestie.
• -version — Print out the version of lli and exit without doing anything else. It's giving "I'm just here to say hi and leave."

🔥 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. So like, don't be reckless, okay?
• -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. So if you don't specify, she'll just figure it out.
• -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. Sometimes less precision is more, you know?
• -enable-no-infs-fp-math — Enable optimizations that assume no Inf values. No infinity, no problems.
• -enable-no-nans-fp-math — Enable optimizations that assume no NAN values. No NANs, no drama.
• -enable-unsafe-fp-math — Causes lli to enable optimizations that may decrease floating point precision. It's giving "risky but worth it" energy. Proceed with caution, bestie.
• -soft-float — Causes lli to generate software floating point library calls instead of equivalent hardware instructions. So she's doing it manually, no hardware shortcuts.

🌈 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. Sometimes you just need to stop scheduling, you know?
• -disable-spill-fusing — Disable fusing of spill code into instructions. No fusing, no fuss.
• -jit-enable-eh — Exception handling should be enabled in the just-in-time compiler. So exceptions are handled, periodt.
• -join-liveintervals — Coalesce copies (default=true). So it's on by default, but you can turn it off if you want.
• -nozero-initialized-in-bss — Don't place zero-initialized symbols into the BSS section. If you don't want that, this is your flag.
• -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. So if things go wrong, you get a 1. If things go right, you get whatever your program returns. Periodt.

🎀 SEE ALSO 🎀

llc(1) — check her out, she's also iconic.

👑 AUTHOR 👑

Maintained by the LLVM Team (https://llvm.org/). They're the ones keeping this whole thing alive, so show some love.

💜 COPYRIGHT 💜

2003-2025, LLVM Project. All rights reserved, bestie.

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This iconic page is from LLVM version 19, dated 2025-01-17, and it's all about LLI(1). Stay slay, bestie. 💅✨