Ubuntu Manpage: llc - LLVM static compiler

NAME

       llc - LLVM static compiler

SYNOPSIS

       llc [options] [filename]

DESCRIPTION

       The  llc  command  compiles  LLVM  source  inputs  into  assembly language for a specified
       architecture.  The assembly language output can then be passed through a native  assembler
       and linker to generate a native executable.

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

OPTIONS

If filename is “-” or omitted, llc reads from standard input. Otherwise, it will from
filename. Inputs can be in either the LLVM assembly language format (.ll) or the LLVM
bitcode format (.bc).

If the -o option is omitted, then llc 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 llc
creates the output filename by taking the input filename, removing any existing .bc
extension, and adding a .s suffix.

Other llc options are described below.

End-user Options
-help Print a summary of command line options.

-O=uint
Generate code at different optimization levels. These correspond to the -O0, -O1,
-O2, and -O3 optimization levels used by clang.

-mtriple=<target triple>
Override the target triple specified in the input file with the specified string.

-march=<arch>
Specify the architecture for which to generate assembly, overriding the target
encoded in the input 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.

-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

-filetype=<output file type>
Specify what kind of output llc should generated. Options are: asm for textual
assembly ( '.s'), obj for native object files ('.o') and null for not emitting
anything (for performance testing).

Note that not all targets support all options.

-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

--frame-pointer
Specify effect of frame pointer elimination optimization (all,non-leaf,none).

--disable-excess-fp-precision
Disable optimizations that may produce excess precision for floating point. Note
that this option can dramatically slow down code on some systems (e.g. X86).

--enable-no-infs-fp-math
Enable optimizations that assume no Inf values.

--enable-no-nans-fp-math
Enable optimizations that assume no NAN values.

--enable-unsafe-fp-math
Enable optimizations that make unsafe assumptions about IEEE math (e.g. that
addition is associative) or may not work for all input ranges. These optimizations
allow the code generator to make use of some instructions which would otherwise not
be usable (such as fsin on X86).

--stats
Print statistics recorded by code-generation passes.

--time-passes
Record the amount of time needed for each pass and print a report to standard
error.

--load=<dso_path>
Dynamically load dso_path (a path to a dynamically shared object) that implements
an LLVM target. This will permit the target name to be used with the -march option
so that code can be generated for that target.

-meabi=[default|gnu|4|5]
Specify which EABI version should conform to. Valid EABI versions are gnu, 4 and
5. Default value (default) depends on the triple.

-stack-size-section
Emit the .stack_sizes section which contains stack size metadata. The section
contains an array of pairs of function symbol values (pointer size) and stack sizes
(unsigned LEB128). The stack size values only include the space allocated in the
function prologue. Functions with dynamic stack allocations are not included.

Tuning/Configuration Options
--print-machineinstrs
Print generated machine code between compilation phases (useful for debugging).

--regalloc=<allocator>
Specify the register allocator to use. Valid register allocators are:

basic
Basic register allocator.

fast
Fast register allocator. It is the default for unoptimized code.

greedy
Greedy register allocator. It is the default for optimized code.

pbqp
Register allocator based on ‘Partitioned Boolean Quadratic Programming’.

--spiller=<spiller>
Specify the spiller to use for register allocators that support it. Currently this
option is used only by the linear scan register allocator. The default spiller is
local. Valid spillers are:

simple
Simple spiller

local
Local spiller

Intel IA-32-specific Options
--x86-asm-syntax=[att|intel]
Specify whether to emit assembly code in AT&T syntax (the default) or Intel syntax.

EXIT STATUS

       If  llc 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

       2003-2020, LLVM Project