home | help 
LLVM-MC(1)			      LLVM			      LLVM-MC(1)

NAME
     llvm-mc - LLVM Machine Code Playground

SYNOPSIS
     llvm-mc [options] [filename]

DESCRIPTION
     The  llvm-mc command take input as the assembly code for a specified archi-
     tecture and generate object file or executable as a output for a  specified
     architecture.

     llvm-mc  provide powerful set of the tool for working with the machine code
     such as encoding of their instruction and	their  internal  representation,
     disassemble string to bytes etc.

     The  choice  of  architecture for the output assembly code is automatically
     determined from the input file, unless the --arch option is used  to  over-
     ride the default.

OPTIONS
     If  the -o option is omitted, then llvm-mc will send its output to standard
     output if the input is from standard input.  If  the  -o  option  specifies
     "-", then the output will also be sent to standard output.

     If no -o option is specified and an input file other than "-" is specified,
     then  llvm-mc creates the output filename by taking the input filename, re-
     moving any existing .s extension, and adding a .o suffix.

     Other llvm-mc options are described below.

   End-user Options
     --help
	    Display available options (--help-hidden for more).

     -o <filename>
	    Use <filename> as the output filename. See	the  summary  above  for
	    more details.

     --arch=<string>
	    Target arch to assemble for, see -version for available targets.

     --as-lex
	    Apply  the	assemblers  "lexer"  to  break the input into tokens and
	    print each of them out.  This is intended to help develop  and  test
	    an assembler implementation.

     --assemble
	    Assemble  assembly file (default), and print the result to assembly.
	    This is useful to design and test instruction parsers, and can be  a
	    useful  tool  when	combined with other llvm-mc flags.  For example,
	    this option may be useful to transcode assembly from  different  di-
	    alects,  e.g.  on  Intel  where you can use -output-asm-variant=1 to
	    translate from AT&T to Intel assembly syntax.  It can also	be  com-
	    bined  with  --show-encoding  to understand how instructions are en-
	    coded.

     --disassemble
	    Parse a series of hex bytes, and print the result  out  as	assembly
	    syntax.

     --mdis
	    Marked up disassembly of string of hex bytes.

     --filetype=[asm,null,obj]
	    Sets  the  output  filetype.  Setting this flag to asm will make the
	    tool output text assembly. Setting this flag to obj  will  make  the
	    tool  output  an object file. Setting it to null causes no output to
	    be created and can be used for timing purposes. The default value is
	    asm.

     -g     Generate DWARF debugging info for assembly source files.

     --large-code-model
	    Create CFI directives that assume the code might be more than 2 GB.

     --main-file-name=<string>
	    Specify the name we should consider the input file.

     --masm-hexfloats
	    Enable MASM-style hex float initializers (3F800000r).

     -mattr=a1,+a2,-a3,...

     Target specific attributes (-mattr=help for details).

     --mcpu=<cpu-name>
	    Target a specific cpu type (-mcpu=help for details).

     --triple=<string>
	    Target triple to assemble for, see -version for available targets.

     --split-dwarf-file=<filename>
	    DWO output filename.

     --show-inst-operands
	    Show instructions operands as parsed.

     --show-inst
	    Show internal instruction representation.

     --show-encoding
	    Show instruction encodings.

     --save-temp-labels
	    Don't discard temporary labels.

     --relax-relocations
	    Emit R_X86_64_GOTPCRELX instead of R_X86_64_GOTPCREL.

     --print-imm-hex
	    Prefer hex format for immediate values.

     --preserve-comments
	    Preserve Comments in outputted assembly.

     --output-asm-variant=<uint>
	    Syntax variant to use for output printing. For example, on x86  tar-
	    gets  --output-asm-variant=0  prints  in  AT&T  syntax,  and  --out-
	    put-asm-variant=1 prints in Intel/MASM syntax.

     --compress-debug-sections=[none|zlib|zstd]
	    Choose DWARF debug sections compression.

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

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

COPYRIGHT
     2003-2026, LLVM Project

17				   2026-08-30			      LLVM-MC(1)
home | help