LLVM-EXTRACT(1)

💖 llvm-extract(1) — the LLVM manual page 💖

🌸 NAME 🌸

llvm-extract — extract a function from an LLVM module.

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✨ SYNOPSIS ✨

llvm-extract [options] --func function-name [filename]

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🦋 DESCRIPTION 🦋

Okay bestie, so llvm-extract takes the name of a function and pulls it out of the LLVM bitcode file you point it at. It’s mainly a debugging tool — the kind of thing you use to shrink a big messy program into a smaller test case when that program is triggering a bug. Very “reduce the chaos” energy 💅.

In addition to extracting the bitcode of the specified function, llvm-extract will also remove unreachable global variables, prototypes, and unused types. Slay, honestly.

llvm-extract reads its input from standard input if filename is omitted or if filename is -. The output is always written to standard output, unless the -o option is specified (see below).

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🎀 OPTIONS 🎀

• --alias alias-name — extract the alias named function-name from the LLVM bitcode. May be specified multiple times to extract multiple alias at once.
• --ralias alias-regular-expr — extract the alias matching alias-regular-expr from the LLVM bitcode. All alias matching the regular expression will be extracted. May be specified multiple times.
• --bb basic-block-specifier — extract basic blocks(s) specified in basic-block-specifier. May be specified multiple times. Each <function:bb[;bb]> specifier pair will create a function. If multiple basic blocks are specified in one pair, the first block in the sequence should dominate the rest.
• --delete — delete specified Globals from Module.
• -f — enable binary output on terminals. Normally, llvm-extract will refuse to write raw bitcode output if the output stream is a terminal. With this option, llvm-extract will write raw bitcode regardless of the output device.
• --func function-name — extract the function named function-name from the LLVM bitcode. May be specified multiple times to extract multiple functions at once.
• --rfunc function-regular-expr — extract the function(s) matching function-regular-expr from the LLVM bitcode. All functions matching the regular expression will be extracted. May be specified multiple times.
• --glob global-name — extract the global variable named global-name from the LLVM bitcode. May be specified multiple times to extract multiple global variables at once.
• --rglob glob-regular-expr — extract the global variable(s) matching global-regular-expr from the LLVM bitcode. All global variables matching the regular expression will be extracted. May be specified multiple times.
• --keep-const-init — preserve the values of constant globals.
• --recursive — recursively extract all called functions.
• -help — print a summary of command line options.
• -o filename — specify the output filename. If filename is - (the default), then llvm-extract sends its output to standard output.
• -S — write output in LLVM intermediate language (instead of bitcode).

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💜 EXIT STATUS 💜

If llvm-extract succeeds, it will exit with 0. Otherwise, if an error occurs, it will exit with a non-zero value.

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🌈 SEE ALSO 🌈

• bugpoint(1) — another one for the reading list, bestie 🫶

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👑 AUTHOR 👑

Maintained by the LLVM Team (https://llvm.org/).

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🍓 COPYRIGHT 🍓

2003-2023, LLVM Project

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That’s the footer tea, fr fr: page 17, date 2023-12-01, and LLVM-EXTRACT(1) — LLVM source/version stamped and everything. Byeee, go extract something iconic 💖✨