llvm/docs/CommandGuide/llc.md - llvm-project - Git at Google


            
            # llc - LLVM static compiler


            ```{program} llc

            
            ```


            ## SYNOPSIS


            {program}`llc` \[*options*\] \[*filename*\]


            ## DESCRIPTION


            The {program}`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 {option}`-march` option is used to

            
            override the default.


            ## OPTIONS


            If `filename` is "`-`" or omitted, {program}`llc` reads from standard input.

            
            Otherwise, it will read from `filename`. Inputs can be in either the LLVM

            
            assembly language format (`.ll`) or the LLVM bitcode format (`.bc`).


            If the {option}`-o` option is omitted, then {program}`llc` will send its output

            
            to standard output if the input is from standard input. If the {option}`-o`

            
            option specifies "`-`", then the output will also be sent to standard output.


            If no {option}`-o` option is specified and an input file other than "`-`" is

            
            specified, then {program}`llc` creates the output filename by taking the input

            
            filename, removing any existing `.bc` extension, and adding a `.s` suffix.


            Other {program}`llc` options are described below.


            ### End-user Options


            :::{option} -help

            
            Print a summary of command line options.

            
            :::


            :::{option} -M

            
            Pass target-specific InstPrinter options.

            
            Refer to the `-M` option of {manpage}`llvm-objdump(1)`.

            
            :::


            :::{option} -o <filename>

            
            Use `<filename>` as the output filename. See the summary above for more

            
            details.

            
            :::


            :::{option} -O=uint

            
            Generate code at different optimization levels. These correspond to the

            
            `-O0`, `-O1`, `-O2`, and `-O3` optimization levels used by

            
            {program}`clang`.

            
            :::


            :::{option} -mtriple=<target triple>

            
            Override the target triple specified in the input file with the specified

            
            string.

            
            :::


            :::{option} -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.

            
            :::


            :::{option} -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:


            ```none

            
            llvm-as < /dev/null | llc -march=xyz -mcpu=help

            
            ```

            
            :::


            :::{option} -mtune=<cpuname>

            
            Specify a specific chip microarchitecture in the current architecture

            
            to tune code for. By default this is inferred from the target triple and

            
            autodetected to the current architecture. For a list of available tuning

            
            CPUs, use:


            ```none

            
            llvm-as < /dev/null | llc -march=xyz -mtune=help

            
            ```

            
            :::


            :::{option} -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.

            
            :::


            :::{option} -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:


            ```none

            
            llvm-as < /dev/null | llc -march=xyz -mattr=help

            
            ```

            
            :::


            :::{option} --frame-pointer

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

            
            :::


            :::{option} --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).

            
            :::


            :::{option} --enable-no-infs-fp-math

            
            Enable optimizations that assume no Inf values.

            
            :::


            :::{option} --enable-no-nans-fp-math

            
            Enable optimizations that assume no NAN values.

            
            :::


            :::{option} --enable-no-signed-zeros-fp-math

            
            Enable FP math optimizations that assume the sign of 0 is insignificant.

            
            :::


            :::{option} --stats

            
            Print statistics recorded by code-generation passes.

            
            :::


            :::{option} --save-stats, --save-stats=cwd, --save-stats=obj

            
            Save LLVM statistics to a file in the current directory

            
            ({option}`--save-stats`/"--save-stats=cwd") or the directory

            
            of the output file ("--save-stats=obj") in JSON format.

            
            :::


            :::{option} --time-passes

            
            Record the amount of time needed for each pass and print a report to standard

            
            error.

            
            :::


            :::{option} -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.

            
            :::


            :::{option} -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.

            
            :::


            :::{option} -remarks-section

            
            Emit the \_\_remarks (MachO) section which contains metadata about remark

            
            diagnostics.

            
            :::


            ### Tuning/Configuration Options


            :::{option} --print-after-isel

            
            Print generated machine code after instruction selection (useful for debugging).

            
            :::


            :::{option} --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'.

            
            :::


            :::{option} --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


            :::{option} --x86-asm-syntax=[att|intel]

            
            Specify whether to emit assembly code in AT&T syntax (the default) or Intel

            
            syntax.

            
            :::


            ## EXIT STATUS


            If {program}`llc` succeeds, it will exit with 0. Otherwise, if an error

            
            occurs, it will exit with a non-zero value.


            ## SEE ALSO


            {manpage}`lli(1)`
	# llc - LLVM static compiler

	```{program} llc
	```

	## SYNOPSIS

	{program}`llc` \[options\] \[filename\]

	## DESCRIPTION

	The {program}`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 {option}`-march` option is used to
	override the default.

	## OPTIONS

	If `filename` is "`-`" or omitted, {program}`llc` reads from standard input.
	Otherwise, it will read from `filename`. Inputs can be in either the LLVM
	assembly language format (`.ll`) or the LLVM bitcode format (`.bc`).

	If the {option}`-o` option is omitted, then {program}`llc` will send its output
	to standard output if the input is from standard input. If the {option}`-o`
	option specifies "`-`", then the output will also be sent to standard output.

	If no {option}`-o` option is specified and an input file other than "`-`" is
	specified, then {program}`llc` creates the output filename by taking the input
	filename, removing any existing `.bc` extension, and adding a `.s` suffix.

	Other {program}`llc` options are described below.

	### End-user Options

	:::{option} -help
	Print a summary of command line options.
	:::

	:::{option} -M
	Pass target-specific InstPrinter options.
	Refer to the `-M` option of {manpage}`llvm-objdump(1)`.
	:::

	:::{option} -o <filename>
	Use `<filename>` as the output filename. See the summary above for more
	details.
	:::

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

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

	:::{option} -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.
	:::

	:::{option} -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:

	```none
	llvm-as < /dev/null \| llc -march=xyz -mcpu=help
	```
	:::

	:::{option} -mtune=<cpuname>
	Specify a specific chip microarchitecture in the current architecture
	to tune code for. By default this is inferred from the target triple and
	autodetected to the current architecture. For a list of available tuning
	CPUs, use:

	```none
	llvm-as < /dev/null \| llc -march=xyz -mtune=help
	```
	:::

	:::{option} -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.
	:::

	:::{option} -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:

	```none
	llvm-as < /dev/null \| llc -march=xyz -mattr=help
	```
	:::

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

	:::{option} --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).
	:::

	:::{option} --enable-no-infs-fp-math
	Enable optimizations that assume no Inf values.
	:::

	:::{option} --enable-no-nans-fp-math
	Enable optimizations that assume no NAN values.
	:::

	:::{option} --enable-no-signed-zeros-fp-math
	Enable FP math optimizations that assume the sign of 0 is insignificant.
	:::

	:::{option} --stats
	Print statistics recorded by code-generation passes.
	:::

	:::{option} --save-stats, --save-stats=cwd, --save-stats=obj
	Save LLVM statistics to a file in the current directory
	({option}`--save-stats`/"--save-stats=cwd") or the directory
	of the output file ("--save-stats=obj") in JSON format.
	:::

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

	:::{option} -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.
	:::

	:::{option} -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.
	:::

	:::{option} -remarks-section
	Emit the \_\_remarks (MachO) section which contains metadata about remark
	diagnostics.
	:::

	### Tuning/Configuration Options

	:::{option} --print-after-isel
	Print generated machine code after instruction selection (useful for debugging).
	:::

	:::{option} --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'.
	:::

	:::{option} --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

	:::{option} --x86-asm-syntax=[att\|intel]
	Specify whether to emit assembly code in AT&T syntax (the default) or Intel
	syntax.
	:::

	## EXIT STATUS

	If {program}`llc` succeeds, it will exit with 0. Otherwise, if an error
	occurs, it will exit with a non-zero value.

	## SEE ALSO

	{manpage}`lli(1)`