llvm-extract - extract a function from an LLVM module¶
SYNOPSIS¶
llvm-extract [options] –func function-name [filename]
DESCRIPTION¶
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).
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) specicified 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).
EXIT STATUS¶
If llvm-extract succeeds, it will exit with 0. Otherwise, if an error occurs, it will exit with a non-zero value.