Man page - llvm-extract-19(1)

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Manual

LLVM-EXTRACT(1) LLVM LLVM-EXTRACT(1)

llvm-extract - extract a function from an LLVM module

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

The llvm-extract command takes the name of a function and extracts it from the specified LLVM bitcode file. It is primarily used as a debugging tool to reduce test cases from larger programs that are triggering a bug.

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

The llvm-extract command 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).

--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).


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

bugpoint(1)

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2025-06-14 15