Clang command line argument reference — Clang 5 documentation

# Clang 5 documentation

## Clang command line argument reference

- Introduction
- Actions
- Compilation flags
  - Preprocessor flags
    - Include path management
    - Dependency file generation
    - Dumping preprocessor state
  - Diagnostic flags
  - Target-independent compilation options
    - OpenCL flags
  - Target-dependent compilation options
    - AARCH64
    - AMDGPU
    - ARM
    - Hexagon
    - PowerPC
    - WebAssembly
    - X86
  - Optimization level
  - Debug information generation
    - Kind and level of debug information
      - Debug level
      - Debugger to tune debug information for
    - Debug information flags
- Static analyzer flags
- Fortran compilation flags
- Linker flags

## Introduction

This page lists the command line arguments currently supported by the GCC-compatible `clang` and `clang++` drivers.

`-B<dir>````,` `--prefix``<arg>``,` `--prefix``=<arg>`

Add <dir> to search path for binaries and object files used implicitly

`-F<arg>```

Add directory to framework include search path

`-ObjC```

Treat source input files as Objective-C inputs

`-ObjC++```

Treat source input files as Objective-C++ inputs

`-Qunused-arguments```

Don’t emit warning for unused driver arguments

`-Wa,<arg>,<arg2>...```

Pass the comma separated arguments in <arg> to the assembler

`-Wlarge-by-value-copy``=<arg>`

`-Xarch_<arg1>``<arg2>`

`-Xcuda-fatbinary``<arg>`

Pass <arg> to fatbinary invocation

`-Xcuda-ptxas``<arg>`

Pass <arg> to the ptxas assembler

`-Z<arg>```

`-a<arg>````,` `--profile-blocks```

`-all_load```

`-allowable_client``<arg>`

`--analyze```

Run the static analyzer

`--analyze-auto```

`--analyzer-no-default-checks```

`--analyzer-output<arg>```

Static analyzer report output format (html|plist|plist-multi-file|plist-html|text).

`-ansi````,` `--ansi```

`-arch``<arg>`

`-arch_errors_fatal```

`-arch_only``<arg>`

`-arcmt-migrate-emit-errors```

Emit ARC errors even if the migrator can fix them

`-arcmt-migrate-report-output``<arg>`

Output path for the plist report

`--autocomplete``=<arg>`

`-bind_at_load```

`-bundle```

`-bundle_loader``<arg>`

`-client_name<arg>```

`-compatibility_version<arg>```

`--constant-cfstrings```

`-coverage````,` `--coverage```

`--cuda-compile-host-device```

Compile CUDA code for both host and device (default). Has no effect on non-CUDA compilations.

`--cuda-device-only```

Compile CUDA code for device only

`--cuda-gpu-arch``=<arg>``,` `--no-cuda-gpu-arch``=<arg>`

CUDA GPU architecture (e.g. sm_35). May be specified more than once.

`--cuda-host-only```

Compile CUDA code for host only. Has no effect on non-CUDA compilations.

`--cuda-noopt-device-debug````,` `--no-cuda-noopt-device-debug```

Enable device-side debug info generation. Disables ptxas optimizations.

`-current_version<arg>```

`-dead_strip```

`-dependency-dot``<arg>`

Filename to write DOT-formatted header dependencies to

`-dependency-file``<arg>`

Filename (or -) to write dependency output to

`-dumpmachine```

`-dumpversion```

`--dyld-prefix``=<arg>``,` `--dyld-prefix``<arg>`

`-dylib_file``<arg>`

`-dylinker```

`-dylinker_install_name<arg>```

`-dynamic```

`-dynamiclib```

`-emit-ast```

Emit Clang AST files for source inputs

`-exported_symbols_list``<arg>`

`-faligned-new``=<arg>`

`-fcuda-approx-transcendentals````,` `-fno-cuda-approx-transcendentals```

Use approximate transcendental functions

`-fcuda-flush-denormals-to-zero````,` `-fno-cuda-flush-denormals-to-zero```

Flush denormal floating point values to zero in CUDA device mode.

`-fheinous-gnu-extensions```

`-flat_namespace```

`-fopenmp-targets``=<arg1>,<arg2>...`

Specify comma-separated list of triples OpenMP offloading targets to be supported

`-force_cpusubtype_ALL```

`-force_flat_namespace```

`-force_load``<arg>`

`-framework``<arg>`

`-frtlib-add-rpath````,` `-fno-rtlib-add-rpath```

Add -rpath with architecture-specific resource directory to the linker flags

`--gcc-toolchain``=<arg>``,` `-gcc-toolchain``<arg>`

Use the gcc toolchain at the given directory

`-gcodeview```

Generate CodeView debug information

`-headerpad_max_install_names<arg>```

`-help````,` `--help```

Display available options

`--help-hidden```

`-image_base``<arg>`

`-index-header-map```

Make the next included directory (-I or -F) an indexer header map

`-init``<arg>`

`-install_name``<arg>`

`-keep_private_externs```

`-lazy_framework``<arg>`

`-lazy_library``<arg>`

`-mbig-endian````,` `-EB```

`--migrate```

Run the migrator

`-mios-simulator-version-min``=<arg>``,` `-miphonesimulator-version-min``=<arg>`

`-mlinker-version``=<arg>`

`-mlittle-endian````,` `-EL```

`-mllvm``<arg>`

Additional arguments to forward to LLVM’s option processing

`-module-dependency-dir``<arg>`

Directory to dump module dependencies to

`-mtvos-simulator-version-min``=<arg>``,` `-mappletvsimulator-version-min``=<arg>`

`-multi_module```

`-multiply_defined``<arg>`

`-multiply_defined_unused``<arg>`

`-mwatchos-simulator-version-min``=<arg>``,` `-mwatchsimulator-version-min``=<arg>`

`--no-cuda-version-check```

Don’t error out if the detected version of the CUDA install is too low for the requested CUDA gpu architecture.

`-no-integrated-cpp````,` `--no-integrated-cpp```

`-no_dead_strip_inits_and_terms```

`-nobuiltininc```

Disable builtin #include directories

`-nocudainc```

`-nocudalib```

`-nodefaultlibs```

`-nofixprebinding```

`-nolibc```

`-nomultidefs```

`-nopie````,` `-no-pie```

`-noprebind```

`-noseglinkedit```

`-nostartfiles```

`-nostdinc````,` `--no-standard-includes```

`-nostdinc++```

Disable standard #include directories for the C++ standard library

`-nostdlib````,` `--no-standard-libraries```

`-nostdlibinc```

`-o<file>````,` `--output``<arg>``,` `--output``=<arg>`

Write output to <file>

`-objcmt-atomic-property```

Make migration to ‘atomic’ properties

`-objcmt-migrate-all```

Enable migration to modern ObjC

`-objcmt-migrate-annotation```

Enable migration to property and method annotations

`-objcmt-migrate-designated-init```

Enable migration to infer NS_DESIGNATED_INITIALIZER for initializer methods

`-objcmt-migrate-instancetype```

Enable migration to infer instancetype for method result type

`-objcmt-migrate-literals```

Enable migration to modern ObjC literals

`-objcmt-migrate-ns-macros```

Enable migration to NS_ENUM/NS_OPTIONS macros

`-objcmt-migrate-property```

Enable migration to modern ObjC property

`-objcmt-migrate-property-dot-syntax```

Enable migration of setter/getter messages to property-dot syntax

`-objcmt-migrate-protocol-conformance```

Enable migration to add protocol conformance on classes

`-objcmt-migrate-readonly-property```

Enable migration to modern ObjC readonly property

`-objcmt-migrate-readwrite-property```

Enable migration to modern ObjC readwrite property

`-objcmt-migrate-subscripting```

Enable migration to modern ObjC subscripting

`-objcmt-ns-nonatomic-iosonly```

Enable migration to use NS_NONATOMIC_IOSONLY macro for setting property’s ‘atomic’ attribute

`-objcmt-returns-innerpointer-property```

Enable migration to annotate property with NS_RETURNS_INNER_POINTER

`-objcmt-whitelist-dir-path``=<arg>``,` `-objcmt-white-list-dir-path``=<arg>`

Only modify files with a filename contained in the provided directory path

`-object```

`-p````,` `--profile```

`-pagezero_size<arg>```

`-pg```

Enable mcount instrumentation

`-pie```

`-pipe````,` `--pipe```

Use pipes between commands, when possible

`-prebind```

`-prebind_all_twolevel_modules```

`-preload```

`--print-diagnostic-categories```

`-print-file-name``=<file>``,` `--print-file-name``=<file>``,` `--print-file-name``<arg>`

Print the full library path of <file>

`-print-ivar-layout```

Enable Objective-C Ivar layout bitmap print trace

`-print-libgcc-file-name````,` `--print-libgcc-file-name```

Print the library path for the currently used compiler runtime library (“libgcc.a” or “libclang_rt.builtins.*.a”)

`-print-multi-directory````,` `--print-multi-directory```

`-print-multi-lib````,` `--print-multi-lib```

`-print-prog-name``=<name>``,` `--print-prog-name``=<name>``,` `--print-prog-name``<arg>`

Print the full program path of <name>

`-print-resource-dir````,` `--print-resource-dir```

Print the resource directory pathname

`-print-search-dirs````,` `--print-search-dirs```

Print the paths used for finding libraries and programs

`-private_bundle```

`-pthread````,` `-no-pthread```

Support POSIX threads in generated code

`-pthreads```

`-rdynamic```

`-read_only_relocs``<arg>`

`-relocatable-pch````,` `--relocatable-pch```

Whether to build a relocatable precompiled header

`-remap```

`-rewrite-legacy-objc```

Rewrite Legacy Objective-C source to C++

`-rtlib``=<arg>``,` `--rtlib``=<arg>``,` `--rtlib``<arg>`

Compiler runtime library to use

`-save-stats``=<arg>``,` `--save-stats``=<arg>``,` `-save-stats``(equivalent to -save-stats=cwd)``,` `--save-stats``(equivalent to -save-stats=cwd)`

Save llvm statistics.

`-save-temps``=<arg>``,` `--save-temps``=<arg>``,` `-save-temps``(equivalent to -save-temps=cwd)``,` `--save-temps``(equivalent to -save-temps=cwd)`

Save intermediate compilation results.

`-sectalign``<arg1> <arg2> <arg3>`

`-sectcreate``<arg1> <arg2> <arg3>`

`-sectobjectsymbols``<arg1> <arg2>`

`-sectorder``<arg1> <arg2> <arg3>`

`-seg1addr<arg>```

`-seg_addr_table``<arg>`

`-seg_addr_table_filename``<arg>`

`-segaddr``<arg1> <arg2>`

`-segcreate``<arg1> <arg2> <arg3>`

`-seglinkedit```

`-segprot``<arg1> <arg2> <arg3>`

`-segs_read_<arg>```

`-segs_read_only_addr``<arg>`

`-segs_read_write_addr``<arg>`

`-serialize-diagnostics``<arg>``,` `--serialize-diagnostics``<arg>`

Serialize compiler diagnostics to a file

`-shared````,` `--shared```

`-shared-libasan```

`-shared-libgcc```

`-single_module```

`-specs``=<arg>``,` `--specs``=<arg>`

`-static````,` `--static```

`-static-libgcc```

`-static-libstdc++```

`-std-default``=<arg>`

`-stdlib``=<arg>``,` `--stdlib``=<arg>``,` `--stdlib``<arg>`

C++ standard library to use

`-sub_library<arg>```

`-sub_umbrella<arg>```

`--sysroot``=<arg>``,` `--sysroot``<arg>`

`--target-help```

`--target``=<arg>``,` `-target``<arg>`

Generate code for the given target

`-time```

Time individual commands

`-traditional````,` `--traditional```

`-traditional-cpp````,` `--traditional-cpp```

Enable some traditional CPP emulation

`-twolevel_namespace```

`-twolevel_namespace_hints```

`-umbrella``<arg>`

`-unexported_symbols_list``<arg>`

`-v````,` `--verbose```

Show commands to run and use verbose output

`--verify-debug-info```

Verify the binary representation of debug output

`--version```

`-w````,` `--no-warnings```

Suppress all warnings

`-weak-l<arg>```

`-weak_framework``<arg>`

`-weak_library``<arg>`

`-weak_reference_mismatches``<arg>`

`-whatsloaded```

`-whyload```

`-working-directory<arg>````,` `-working-directory``=<arg>`

Resolve file paths relative to the specified directory

`-x<language>````,` `--language``<arg>``,` `--language``=<arg>`

Treat subsequent input files as having type <language>

`-y<arg>```

## Actions

The action to perform on the input.

`-E````,` `--preprocess```

Only run the preprocessor

`-S````,` `--assemble```

Only run preprocess and compilation steps

`-c````,` `--compile```

Only run preprocess, compile, and assemble steps

`-emit-llvm```

Use the LLVM representation for assembler and object files

`-fsyntax-only```

`-module-file-info```

Provide information about a particular module file

`--precompile```

Only precompile the input

`-rewrite-objc```

Rewrite Objective-C source to C++

`-verify-pch```

Load and verify that a pre-compiled header file is not stale

## Compilation flags

Flags controlling the behavior of Clang during compilation. These flags have no effect during actions that do not perform compilation.

`-Xassembler``<arg>`

Pass <arg> to the assembler

`-Xclang``<arg>`

Pass <arg> to the clang compiler

`-fclang-abi-compat``=<version>`

Attempt to match the ABI of Clang <version>

`-fcomment-block-commands``=<arg>,<arg2>...`

Treat each comma separated argument in <arg> as a documentation comment block command

`-fdeclspec````,` `-fno-declspec```

Allow __declspec as a keyword

`-fdepfile-entry``=<arg>`

`-fdiagnostics-fixit-info````,` `-fno-diagnostics-fixit-info```

`-fdiagnostics-format``=<arg>`

`-fdiagnostics-parseable-fixits```

Print fix-its in machine parseable form

`-fdiagnostics-print-source-range-info```

Print source range spans in numeric form

`-fdiagnostics-show-category``=<arg>`

`-fexperimental-new-pass-manager````,` `-fno-experimental-new-pass-manager```

Enables an experimental new pass manager in LLVM.

`-finline-functions````,` `-fno-inline-functions```

Inline suitable functions

`-finline-hint-functions```

Inline functions which are (explicitly or implicitly) marked inline

`-fno-crash-diagnostics```

Disable auto-generation of preprocessed source files and a script for reproduction during a clang crash

`-fno-sanitize-blacklist```

Don’t use blacklist file for sanitizers

`-fparse-all-comments```

`-fsanitize-address-field-padding``=<arg>`

Level of field padding for AddressSanitizer

`-fsanitize-address-globals-dead-stripping```

Enable linker dead stripping of globals in AddressSanitizer

`-fsanitize-address-use-after-scope````,` `-fno-sanitize-address-use-after-scope```

Enable use-after-scope detection in AddressSanitizer

`-fsanitize-blacklist``=<arg>`

Path to blacklist file for sanitizers

`-fsanitize-cfi-cross-dso````,` `-fno-sanitize-cfi-cross-dso```

Enable control flow integrity (CFI) checks for cross-DSO calls.

`-fsanitize-coverage``=<arg1>,<arg2>...``,` `-fno-sanitize-coverage``=<arg1>,<arg2>...`

Specify the type of coverage instrumentation for Sanitizers

`-fsanitize-link-c++-runtime```

`-fsanitize-memory-track-origins````,` `-fno-sanitize-memory-track-origins```

Enable origins tracking in MemorySanitizer

`-fsanitize-memory-track-origins``=<arg>`

Enable origins tracking in MemorySanitizer

`-fsanitize-memory-use-after-dtor```

Enable use-after-destroy detection in MemorySanitizer

`-fsanitize-recover````,` `-fno-sanitize-recover```

`-fsanitize-recover``=<arg1>,<arg2>...``,` `-fno-sanitize-recover``=<arg1>,<arg2>...`

Enable recovery for specified sanitizers

`-fsanitize-stats````,` `-fno-sanitize-stats```

Enable sanitizer statistics gathering.

`-fsanitize-thread-atomics````,` `-fno-sanitize-thread-atomics```

Enable atomic operations instrumentation in ThreadSanitizer (default)

`-fsanitize-thread-func-entry-exit````,` `-fno-sanitize-thread-func-entry-exit```

Enable function entry/exit instrumentation in ThreadSanitizer (default)

`-fsanitize-thread-memory-access````,` `-fno-sanitize-thread-memory-access```

Enable memory access instrumentation in ThreadSanitizer (default)

`-fsanitize-trap``=<arg1>,<arg2>...``,` `-fno-sanitize-trap``=<arg1>,<arg2>...`

Enable trapping for specified sanitizers

`-fsanitize-undefined-strip-path-components``=<number>`

Strip (or keep only, if negative) a given number of path components when emitting check metadata.

`-fsanitize-undefined-trap-on-error````,` `-fno-sanitize-undefined-trap-on-error```

`-fsanitize``=<check>,<arg2>...``,` `-fno-sanitize``=<arg1>,<arg2>...`

Turn on runtime checks for various forms of undefined or suspicious behavior. See user manual for available checks

`--param``<arg>``,` `--param``=<arg>`

`-std``=<arg>``,` `--std``=<arg>``,` `--std``<arg>`

Language standard to compile for

### Preprocessor flags

Flags controlling the behavior of the Clang preprocessor.

`-C````,` `--comments```

Include comments in preprocessed output

`-CC````,` `--comments-in-macros```

Include comments from within macros in preprocessed output

`-D<macro>``=<value>``,` `--define-macro``<arg>``,` `--define-macro``=<arg>`

Define <macro> to <value> (or 1 if <value> omitted)

`-H````,` `--trace-includes```

Show header includes and nesting depth

`-P````,` `--no-line-commands```

Disable linemarker output in -E mode

`-U<macro>````,` `--undefine-macro``<arg>``,` `--undefine-macro``=<arg>`

Undefine macro <macro>

`-Wp,<arg>,<arg2>...```

Pass the comma separated arguments in <arg> to the preprocessor

`-Xpreprocessor``<arg>`

Pass <arg> to the preprocessor

#### Include path management

Flags controlling how `#include`s are resolved to files.

`-I<dir>````,` `--include-directory``<arg>``,` `--include-directory``=<arg>`

Add directory to include search path

`-I-````,` `--include-barrier```

Restrict all prior -I flags to double-quoted inclusion and remove current directory from include path

`--cuda-path``=<arg>`

CUDA installation path

`-cxx-isystem<directory>```

Add directory to the C++ SYSTEM include search path

`-fbuild-session-file``=<file>`

Use the last modification time of <file> as the build session timestamp

`-fbuild-session-timestamp``=<time since Epoch in seconds>`

Time when the current build session started

`-fmodules-cache-path``=<directory>`

Specify the module cache path

`-fmodules-disable-diagnostic-validation```

Disable validation of the diagnostic options when loading the module

`-fmodules-prune-after``=<seconds>`

Specify the interval (in seconds) after which a module file will be considered unused

`-fmodules-prune-interval``=<seconds>`

Specify the interval (in seconds) between attempts to prune the module cache

`-fmodules-user-build-path``<directory>`

Specify the module user build path

`-fmodules-validate-once-per-build-session```

Don’t verify input files for the modules if the module has been successfully validated or loaded during this build session

`-fmodules-validate-system-headers```

Validate the system headers that a module depends on when loading the module

`-fprebuilt-module-path``=<directory>`

Specify the prebuilt module path

`-i<arg>```

`-idirafter<arg>````,` `--include-directory-after``<arg>``,` `--include-directory-after``=<arg>`

Add directory to AFTER include search path

`-iframework<arg>```

Add directory to SYSTEM framework search path

`-iframeworkwithsysroot<directory>```

Add directory to SYSTEM framework search path, absolute paths are relative to -isysroot

`-imacros<file>````,` `--imacros<file>````,` `--imacros``=<arg>`

Include macros from file before parsing

`-include<file>````,` `--include<file>````,` `--include``=<arg>`

Include file before parsing

`-include-pch``<file>`

Include precompiled header file

`-iprefix<dir>````,` `--include-prefix``<arg>``,` `--include-prefix``=<arg>`

Set the -iwithprefix/-iwithprefixbefore prefix

`-iquote<directory>```

Add directory to QUOTE include search path

`-isysroot<dir>```

Set the system root directory (usually /)

`-isystem<directory>```

Add directory to SYSTEM include search path

`-isystem-after<directory>```

Add directory to end of the SYSTEM include search path

`-ivfsoverlay<arg>```

Overlay the virtual filesystem described by file over the real file system

`-iwithprefix<dir>````,` `--include-with-prefix``<arg>``,` `--include-with-prefix-after``<arg>``,` `--include-with-prefix-after``=<arg>``,` `--include-with-prefix``=<arg>`

Set directory to SYSTEM include search path with prefix

`-iwithprefixbefore<dir>````,` `--include-with-prefix-before``<arg>``,` `--include-with-prefix-before``=<arg>`

Set directory to include search path with prefix

`-iwithsysroot<directory>```

Add directory to SYSTEM include search path, absolute paths are relative to -isysroot

`--ptxas-path``=<arg>`

Path to ptxas (used for compiling CUDA code)

`--system-header-prefix``=<prefix>``,` `--no-system-header-prefix``=<prefix>``,` `--system-header-prefix``<arg>`

Treat all #include paths starting with <prefix> as including a system header.

#### Dependency file generation

Flags controlling generation of a dependency file for `make`-like build systems.

`-M````,` `--dependencies```

Like -MD, but also implies -E and writes to stdout by default

`-MD````,` `--write-dependencies```

Write a depfile containing user and system headers

`-MF<file>```

Write depfile output from -MMD, -MD, -MM, or -M to <file>

`-MG````,` `--print-missing-file-dependencies```

Add missing headers to depfile

`-MJ<arg>```

Write a compilation database entry per input

`-MM````,` `--user-dependencies```

Like -MMD, but also implies -E and writes to stdout by default

`-MMD````,` `--write-user-dependencies```

Write a depfile containing user headers

`-MP```

Create phony target for each dependency (other than main file)

`-MQ<arg>```

Specify name of main file output to quote in depfile

`-MT<arg>```

Specify name of main file output in depfile

`-MV```

Use NMake/Jom format for the depfile

#### Dumping preprocessor state

Flags allowing the state of the preprocessor to be dumped in various ways.

`-d```

`-d<arg>```

`-dA```

`-dD```

Print macro definitions in -E mode in addition to normal output

`-dI```

Print include directives in -E mode in addition to normal output

`-dM```

Print macro definitions in -E mode instead of normal output

### Diagnostic flags

Flags controlling which warnings, errors, and remarks Clang will generate. See the full list of warning and remark flags.

`-R<remark>```

Enable the specified remark

`-Rpass-analysis``=<arg>`

Report transformation analysis from optimization passes whose name matches the given POSIX regular expression

`-Rpass-missed``=<arg>`

Report missed transformations by optimization passes whose name matches the given POSIX regular expression

`-Rpass``=<arg>`

Report transformations performed by optimization passes whose name matches the given POSIX regular expression

`-W<warning>````,` `--extra-warnings````,` `--warn-<arg>````,` `--warn-``=<arg>`

Enable the specified warning

`-Wdeprecated````,` `-Wno-deprecated```

Enable warnings for deprecated constructs and define __DEPRECATED

`-Wnonportable-cfstrings<arg>````,` `-Wno-nonportable-cfstrings<arg>```

### Target-independent compilation options

`-Wframe-larger-than``=<arg>`

`-fPIC````,` `-fno-PIC```

`-fPIE````,` `-fno-PIE```

`-faccess-control````,` `-fno-access-control```

`-faligned-allocation````,` `-faligned-new````,` `-fno-aligned-allocation```

Enable C++17 aligned allocation functions

`-fallow-editor-placeholders````,` `-fno-allow-editor-placeholders```

Treat editor placeholders as valid source code

`-fallow-unsupported```

`-faltivec````,` `-fno-altivec```

`-fansi-escape-codes```

Use ANSI escape codes for diagnostics

`-fapple-kext````,` `-findirect-virtual-calls````,` `-fterminated-vtables```

Use Apple’s kernel extensions ABI

`-fapple-pragma-pack````,` `-fno-apple-pragma-pack```

Enable Apple gcc-compatible #pragma pack handling

`-fapplication-extension````,` `-fno-application-extension```

Restrict code to those available for App Extensions

`-fasm````,` `-fno-asm```

`-fasm-blocks````,` `-fno-asm-blocks```

`-fassociative-math````,` `-fno-associative-math```

`-fassume-sane-operator-new````,` `-fno-assume-sane-operator-new```

`-fast```

`-fastcp```

`-fastf```

`-fasynchronous-unwind-tables````,` `-fno-asynchronous-unwind-tables```

`-fautolink````,` `-fno-autolink```

`-fblocks````,` `-fno-blocks```

Enable the ‘blocks’ language feature

`-fbootclasspath``=<arg>``,` `--bootclasspath``<arg>``,` `--bootclasspath``=<arg>`

`-fborland-extensions````,` `-fno-borland-extensions```

Accept non-standard constructs supported by the Borland compiler

`-fbracket-depth``=<arg>`

`-fbuiltin````,` `-fno-builtin```

`-fbuiltin-module-map```

Load the clang builtins module map file.

`-fcaret-diagnostics````,` `-fno-caret-diagnostics```

`-fclasspath``=<arg>``,` `--CLASSPATH``<arg>``,` `--CLASSPATH``=<arg>``,` `--classpath``<arg>``,` `--classpath``=<arg>`

`-fcolor-diagnostics````,` `-fno-color-diagnostics```

Use colors in diagnostics

`-fcommon````,` `-fno-common```

`-fcompile-resource``=<arg>``,` `--resource``<arg>``,` `--resource``=<arg>`

`-fconstant-cfstrings````,` `-fno-constant-cfstrings```

`-fconstant-string-class``=<arg>`

`-fconstexpr-backtrace-limit``=<arg>`

`-fconstexpr-depth``=<arg>`

`-fconstexpr-steps``=<arg>`

`-fcoroutines-ts````,` `-fno-coroutines-ts```

Enable support for the C++ Coroutines TS

`-fcoverage-mapping````,` `-fno-coverage-mapping```

Generate coverage mapping to enable code coverage analysis

`-fcreate-profile```

`-fcxx-exceptions````,` `-fno-cxx-exceptions```

Enable C++ exceptions

`-fcxx-modules````,` `-fno-cxx-modules```

`-fdata-sections````,` `-fno-data-sections```

Place each data in its own section (ELF Only)

`-fdebug-info-for-profiling````,` `-fno-debug-info-for-profiling```

Emit extra debug info to make sample profile more accurate.

`-fdebug-macro````,` `-fno-debug-macro```

Emit macro debug information

`-fdebug-pass-arguments```

`-fdebug-pass-structure```

`-fdebug-prefix-map``=<arg>`

remap file source paths in debug info

`-fdebug-types-section````,` `-fno-debug-types-section```

Place debug types in their own section (ELF Only)

`-fdelayed-template-parsing````,` `-fno-delayed-template-parsing```

Parse templated function definitions at the end of the translation unit

`-fdenormal-fp-math``=<arg>`

`-fdiagnostics-absolute-paths```

Print absolute paths in diagnostics

`-fdiagnostics-color````,` `-fno-diagnostics-color```

`-fdiagnostics-color``=<arg>`

`-fdiagnostics-hotness-threshold``=<number>`

Prevent optimization remarks from being output if they do not have at least this profile count

`-fdiagnostics-show-hotness````,` `-fno-diagnostics-show-hotness```

Enable profile hotness information in diagnostic line

`-fdiagnostics-show-note-include-stack````,` `-fno-diagnostics-show-note-include-stack```

Display include stacks for diagnostic notes

`-fdiagnostics-show-option````,` `-fno-diagnostics-show-option```

Print option name with mappable diagnostics

`-fdiagnostics-show-template-tree```

Print a template comparison tree for differing templates

`-fdollars-in-identifiers````,` `-fno-dollars-in-identifiers```

Allow ‘$’ in identifiers

`-fdwarf-directory-asm````,` `-fno-dwarf-directory-asm```

`-felide-constructors````,` `-fno-elide-constructors```

`-feliminate-unused-debug-symbols````,` `-fno-eliminate-unused-debug-symbols```

`-fembed-bitcode``=<option>``,` `-fembed-bitcode``(equivalent to -fembed-bitcode=all)``,` `-fembed-bitcode-marker``(equivalent to -fembed-bitcode=marker)`

Embed LLVM bitcode (option: off, all, bitcode, marker)

`-femit-all-decls```

Emit all declarations, even if unused

`-femulated-tls````,` `-fno-emulated-tls```

Use emutls functions to access thread_local variables

`-fencoding``=<arg>``,` `--encoding``<arg>``,` `--encoding``=<arg>`

`-ferror-limit``=<arg>`

`-fexceptions````,` `-fno-exceptions```

Enable support for exception handling

`-fexec-charset``=<arg>`

`-fextdirs``=<arg>``,` `--extdirs``<arg>``,` `--extdirs``=<arg>`

`-ffast-math````,` `-fno-fast-math```

Allow aggressive, lossy floating-point optimizations

`-ffinite-math-only````,` `-fno-finite-math-only```

`-ffor-scope````,` `-fno-for-scope```

`-ffp-contract``=<arg>`

Form fused FP ops (e.g. FMAs): fast (everywhere) | on (according to FP_CONTRACT pragma, default) | off (never fuse)

`-ffreestanding```

Assert that the compilation takes place in a freestanding environment

`-ffunction-sections````,` `-fno-function-sections```

Place each function in its own section (ELF Only)

`-fgnu-inline-asm````,` `-fno-gnu-inline-asm```

`-fgnu-keywords````,` `-fno-gnu-keywords```

Allow GNU-extension keywords regardless of language standard

`-fgnu-runtime```

Generate output compatible with the standard GNU Objective-C runtime

`-fgnu89-inline````,` `-fno-gnu89-inline```

Use the gnu89 inline semantics

`-fhonor-infinities````,` `-fhonor-infinites````,` `-fno-honor-infinities```

`-fhonor-nans````,` `-fno-honor-nans```

`-fhosted```

`-fimplicit-module-maps````,` `-fmodule-maps````,` `-fno-implicit-module-maps```

Implicitly search the file system for module map files.

`-fimplicit-modules````,` `-fno-implicit-modules```

`-finput-charset``=<arg>`

`-finstrument-functions```

Generate calls to instrument function entry and exit

`-fintegrated-as````,` `-fno-integrated-as````,` `-integrated-as```

Enable the integrated assembler

`-fjump-tables````,` `-fno-jump-tables```

`-flax-vector-conversions````,` `-fno-lax-vector-conversions```

`-flimited-precision``=<arg>`

`-flto````,` `-fno-lto```

Enable LTO in ‘full’ mode

`-flto-jobs``=<arg>`

Controls the backend parallelism of -flto=thin (default of 0 means the number of threads will be derived from the number of CPUs detected)

`-flto``=<arg>`

Set LTO mode to either ‘full’ or ‘thin’

`-fmacro-backtrace-limit``=<arg>`

`-fmath-errno````,` `-fno-math-errno```

Require math functions to indicate errors by setting errno

`-fmax-type-align``=<arg>`

Specify the maximum alignment to enforce on pointers lacking an explicit alignment

`-fmerge-all-constants````,` `-fno-merge-all-constants```

`-fmessage-length``=<arg>`

`-fmodule-file-deps````,` `-fno-module-file-deps```

`-fmodule-file``=<file>`

Load this precompiled module file

`-fmodule-map-file``=<file>`

Load this module map file

`-fmodule-name``=<name>``,` `-fmodule-implementation-of``<arg>``,` `-fmodule-name``<arg>`

Specify the name of the module to build

`-fmodules````,` `-fno-modules```

Enable the ‘modules’ language feature

`-fmodules-decluse````,` `-fno-modules-decluse```

Require declaration of modules used within a module

`-fmodules-ignore-macro``=<arg>`

Ignore the definition of the given macro when building and loading modules

`-fmodules-search-all````,` `-fno-modules-search-all```

Search even non-imported modules to resolve references

`-fmodules-strict-decluse```

Like -fmodules-decluse but requires all headers to be in modules

`-fmodules-ts```

Enable support for the C++ Modules TS

`-fms-compatibility````,` `-fno-ms-compatibility```

Enable full Microsoft Visual C++ compatibility

`-fms-compatibility-version``=<arg>`

Dot-separated value representing the Microsoft compiler version number to report in _MSC_VER (0 = don’t define it (default))

`-fms-extensions````,` `-fno-ms-extensions```

Accept some non-standard constructs supported by the Microsoft compiler

`-fms-memptr-rep``=<arg>`

`-fms-volatile<arg>```

`-fmsc-version``=<arg>`

Microsoft compiler version number to report in _MSC_VER (0 = don’t define it (default))

`-fmudflap```

`-fmudflapth```

`-fnested-functions```

`-fnew-alignment``=<align>``,` `-fnew-alignment``<arg>`

Specifies the largest alignment guaranteed by ‘::operator new(size_t)’

`-fnext-runtime```

`-fno-builtin-<arg>```

Disable implicit builtin knowledge of a specific function

`-fno-elide-type```

Do not elide types when printing diagnostics

`-fno-max-type-align```

`-fno-operator-names```

Do not treat C++ operator name keywords as synonyms for operators

`-fno-strict-modules-decluse```

`-fno-working-directory```

`-fnoopenmp-use-tls```

`-fobjc-abi-version``=<arg>`

`-fobjc-arc````,` `-fno-objc-arc```

Synthesize retain and release calls for Objective-C pointers

`-fobjc-arc-exceptions````,` `-fno-objc-arc-exceptions```

Use EH-safe code when synthesizing retains and releases in -fobjc-arc

`-fobjc-exceptions````,` `-fno-objc-exceptions```

Enable Objective-C exceptions

`-fobjc-infer-related-result-type````,` `-fno-objc-infer-related-result-type```

`-fobjc-legacy-dispatch````,` `-fno-objc-legacy-dispatch```

`-fobjc-link-runtime```

`-fobjc-nonfragile-abi````,` `-fno-objc-nonfragile-abi```

`-fobjc-nonfragile-abi-version``=<arg>`

`-fobjc-runtime``=<arg>`

Specify the target Objective-C runtime kind and version

`-fobjc-sender-dependent-dispatch```

`-fobjc-weak````,` `-fno-objc-weak```

Enable ARC-style weak references in Objective-C

`-fomit-frame-pointer````,` `-fno-omit-frame-pointer```

`-fopenmp````,` `-fno-openmp```

`-fopenmp-dump-offload-linker-script```

`-fopenmp-use-tls```

`-fopenmp-version``=<arg>`

`-fopenmp``=<arg>`

`-foperator-arrow-depth``=<arg>`

`-foptimization-record-file``=<arg>`

Specify the file name of any generated YAML optimization record

`-foptimize-sibling-calls````,` `-fno-optimize-sibling-calls```

`-foutput-class-dir``=<arg>``,` `--output-class-directory``<arg>``,` `--output-class-directory``=<arg>`

`-fpack-struct````,` `-fno-pack-struct```

`-fpack-struct``=<arg>`

Specify the default maximum struct packing alignment

`-fpascal-strings````,` `-fno-pascal-strings````,` `-mpascal-strings```

Recognize and construct Pascal-style string literals

`-fpcc-struct-return```

Override the default ABI to return all structs on the stack

`-fpch-preprocess```

`-fpic````,` `-fno-pic```

`-fpie````,` `-fno-pie```

`-fplugin``=<dsopath>`

Load the named plugin (dynamic shared object)

`-fpreserve-as-comments````,` `-fno-preserve-as-comments```

`-fprofile-arcs````,` `-fno-profile-arcs```

`-fprofile-dir``=<arg>`

`-fprofile-generate````,` `-fno-profile-generate```

Generate instrumented code to collect execution counts into default.profraw (overridden by LLVM_PROFILE_FILE env var)

`-fprofile-generate``=<directory>`

Generate instrumented code to collect execution counts into <directory>/default.profraw (overridden by LLVM_PROFILE_FILE env var)

`-fprofile-instr-generate````,` `-fno-profile-instr-generate```

Generate instrumented code to collect execution counts into default.profraw file (overridden by ‘=’ form of option or LLVM_PROFILE_FILE env var)

`-fprofile-instr-generate``=<file>`

Generate instrumented code to collect execution counts into <file> (overridden by LLVM_PROFILE_FILE env var)

`-fprofile-instr-use````,` `-fno-profile-instr-use````,` `-fprofile-use```

`-fprofile-instr-use``=<arg>`

Use instrumentation data for profile-guided optimization

`-fprofile-sample-use````,` `-fauto-profile````,` `-fno-profile-sample-use```

`-fprofile-sample-use``=<arg>``,` `-fauto-profile``=<arg>`

Enable sample-based profile guided optimizations

`-fprofile-use``=<pathname>`

Use instrumentation data for profile-guided optimization. If pathname is a directory, it reads from <pathname>/default.profdata. Otherwise, it reads from file <pathname>.

`-freciprocal-math````,` `-fno-reciprocal-math```

Allow division operations to be reassociated

`-freg-struct-return```

Override the default ABI to return small structs in registers

`-frelaxed-template-template-args````,` `-fno-relaxed-template-template-args```

Enable C++17 relaxed template template argument matching

`-freroll-loops````,` `-fno-reroll-loops```

Turn on loop reroller

`-fretain-comments-from-system-headers```

`-frewrite-imports````,` `-fno-rewrite-imports```

`-frewrite-includes````,` `-fno-rewrite-includes```

`-frewrite-map-file``<arg>`

`-frewrite-map-file``=<arg>`

`-fropi````,` `-fno-ropi```

`-frtti````,` `-fno-rtti```

`-frwpi````,` `-fno-rwpi```

`-fsave-optimization-record````,` `-fno-save-optimization-record```

Generate a YAML optimization record file

`-fshort-enums````,` `-fno-short-enums```

Allocate to an enum type only as many bytes as it needs for the declared range of possible values

`-fshort-wchar````,` `-fno-short-wchar```

Force wchar_t to be a short unsigned int

`-fshow-column````,` `-fno-show-column```

`-fshow-overloads``=<arg>`

Which overload candidates to show when overload resolution fails: best|all; defaults to all

`-fshow-source-location````,` `-fno-show-source-location```

`-fsignaling-math````,` `-fno-signaling-math```

`-fsigned-bitfields```

`-fsigned-char````,` `-fno-signed-char````,` `--signed-char```

`-fsigned-zeros````,` `-fno-signed-zeros```

`-fsized-deallocation````,` `-fno-sized-deallocation```

Enable C++14 sized global deallocation functions

`-fsjlj-exceptions```

Use SjLj style exceptions

`-fslp-vectorize````,` `-fno-slp-vectorize````,` `-ftree-slp-vectorize```

Enable the superword-level parallelism vectorization passes

`-fspell-checking````,` `-fno-spell-checking```

`-fspell-checking-limit``=<arg>`

`-fsplit-dwarf-inlining````,` `-fno-split-dwarf-inlining```

Place debug types in their own section (ELF Only)

`-fsplit-stack```

`-fstack-protector````,` `-fno-stack-protector```

Enable stack protectors for functions potentially vulnerable to stack smashing

`-fstack-protector-all```

Force the usage of stack protectors for all functions

`-fstack-protector-strong```

Use a strong heuristic to apply stack protectors to functions

`-fstandalone-debug````,` `-fno-limit-debug-info````,` `-fno-standalone-debug```

Emit full debug info for all types used by the program

`-fstrict-aliasing````,` `-fno-strict-aliasing```

`-fstrict-enums````,` `-fno-strict-enums```

Enable optimizations based on the strict definition of an enum’s value range

`-fstrict-overflow````,` `-fno-strict-overflow```

`-fstrict-return````,` `-fno-strict-return```

Always treat control flow paths that fall off the end of a non-void function as unreachable

`-fstrict-vtable-pointers````,` `-fno-strict-vtable-pointers```

Enable optimizations based on the strict rules for overwriting polymorphic C++ objects

`-fstruct-path-tbaa````,` `-fno-struct-path-tbaa```

`-ftabstop``=<arg>`

`-ftemplate-backtrace-limit``=<arg>`

`-ftemplate-depth-<arg>```

`-ftemplate-depth``=<arg>`

`-ftest-coverage```

`-fthinlto-index``=<arg>`

Perform ThinLTO importing using provided function summary index

`-fthreadsafe-statics````,` `-fno-threadsafe-statics```

`-ftime-report```

`-ftls-model``=<arg>`

`-ftrap-function``=<arg>`

Issue call to specified function rather than a trap instruction

`-ftrapping-math````,` `-fno-trapping-math```

`-ftrapv```

Trap on integer overflow

`-ftrapv-handler``<arg>`

`-ftrapv-handler``=<function name>`

Specify the function to be called on overflow

`-ftrigraphs````,` `-fno-trigraphs````,` `-trigraphs````,` `--trigraphs```

Process trigraph sequences

`-funique-section-names````,` `-fno-unique-section-names```

Use unique names for text and data sections (ELF Only)

`-funit-at-a-time````,` `-fno-unit-at-a-time```

`-funroll-loops````,` `-fno-unroll-loops```

Turn on loop unroller

`-funsafe-math-optimizations````,` `-fno-unsafe-math-optimizations```

`-funsigned-bitfields```

`-funsigned-char````,` `-fno-unsigned-char````,` `--unsigned-char```

`-funwind-tables````,` `-fno-unwind-tables```

`-fuse-cxa-atexit````,` `-fno-use-cxa-atexit```

`-fuse-init-array````,` `-fno-use-init-array```

Use .init_array instead of .ctors

`-fuse-ld``=<arg>`

`-fuse-line-directives````,` `-fno-use-line-directives```

`-fveclib``=<arg>`

Use the given vector functions library

`-fvectorize````,` `-fno-vectorize````,` `-ftree-vectorize```

Enable the loop vectorization passes

`-fverbose-asm````,` `-fno-verbose-asm```

`-fvisibility-inlines-hidden```

Give inline C++ member functions default visibility by default

`-fvisibility-ms-compat```

Give global types ‘default’ visibility and global functions and variables ‘hidden’ visibility by default

`-fvisibility``=<arg>`

Set the default symbol visibility for all global declarations

`-fwhole-program-vtables````,` `-fno-whole-program-vtables```

Enables whole-program vtable optimization. Requires -flto

`-fwrapv````,` `-fno-wrapv```

Treat signed integer overflow as two’s complement

`-fwritable-strings```

Store string literals as writable data

`-fxray-always-instrument``=<arg>`

Filename defining the whitelist for imbuing the ‘always instrument’ XRay attribute.

`-fxray-instruction-threshold<arg>```

`-fxray-instruction-threshold``=<arg>`

Sets the minimum function size to instrument with XRay

`-fxray-instrument````,` `-fno-xray-instrument```

Generate XRay instrumentation sleds on function entry and exit

`-fxray-never-instrument``=<arg>`

Filename defining the whitelist for imbuing the ‘never instrument’ XRay attribute.

`-fzero-initialized-in-bss````,` `-fno-zero-initialized-in-bss```

`-fzvector````,` `-fno-zvector````,` `-mzvector```

Enable System z vector language extension

`-pedantic````,` `--pedantic````,` `-no-pedantic````,` `--no-pedantic```

`-pedantic-errors````,` `--pedantic-errors```

#### OpenCL flags

`-cl-denorms-are-zero```

OpenCL only. Allow denormals to be flushed to zero.

`-cl-fast-relaxed-math```

OpenCL only. Sets -cl-finite-math-only and -cl-unsafe-math-optimizations, and defines __FAST_RELAXED_MATH__.

`-cl-finite-math-only```

OpenCL only. Allow floating-point optimizations that assume arguments and results are not NaNs or +-Inf.

`-cl-fp32-correctly-rounded-divide-sqrt```

OpenCL only. Specify that single precision floating-point divide and sqrt used in the program source are correctly rounded.

`-cl-kernel-arg-info```

OpenCL only. Generate kernel argument metadata.

`-cl-mad-enable```

OpenCL only. Allow use of less precise MAD computations in the generated binary.

`-cl-no-signed-zeros```

OpenCL only. Allow use of less precise no signed zeros computations in the generated binary.

`-cl-opt-disable```

OpenCL only. This option disables all optimizations. By default optimizations are enabled.

`-cl-single-precision-constant```

OpenCL only. Treat double precision floating-point constant as single precision constant.

`-cl-std``=<arg>`

OpenCL language standard to compile for.

`-cl-strict-aliasing```

OpenCL only. This option is added for compatibility with OpenCL 1.0.

`-cl-unsafe-math-optimizations```

OpenCL only. Allow unsafe floating-point optimizations. Also implies -cl-no-signed-zeros and -cl-mad-enable.

### Target-dependent compilation options

`-G<size>````,` `-G``=<arg>``,` `-msmall-data-threshold``=<arg>`

Put objects of at most <size> bytes into small data section (MIPS / Hexagon)

`-m16```

`-m32```

`-m64```

`-mabi``=<arg>`

`-mabicalls````,` `-mno-abicalls```

Enable SVR4-style position-independent code (Mips only)

`-malign-double```

Align doubles to two words in structs (x86 only)

`-march``=<arg>`

`-masm``=<arg>`

`-mbackchain````,` `-mno-backchain```

Link stack frames through backchain on System Z

`-mcheck-zero-division````,` `-mno-check-zero-division```

`-mcmodel``=<arg>`

`-mcompact-branches``=<arg>`

`-mconsole<arg>```

`-mcpu``=<arg>``,` `-mv4``(equivalent to -mcpu=hexagonv4)``,` `-mv5``(equivalent to -mcpu=hexagonv5)``,` `-mv55``(equivalent to -mcpu=hexagonv55)``,` `-mv60``(equivalent to -mcpu=hexagonv60)``,` `-mv62``(equivalent to -mcpu=hexagonv62)`

`-mdefault-build-attributes<arg>````,` `-mno-default-build-attributes<arg>```

`-mdll<arg>```

`-mdouble-float```

`-mdsp````,` `-mno-dsp```

`-mdspr2````,` `-mno-dspr2```

`-mdynamic-no-pic<arg>```

`-meabi``<arg>`

Set EABI type, e.g. 4, 5 or gnu (default depends on triple)

`-mfentry```

Insert calls to fentry at function entry (x86 only)

`-mfloat-abi``=<arg>`

`-mfp32```

Use 32-bit floating point registers (MIPS only)

`-mfp64```

Use 64-bit floating point registers (MIPS only)

`-mfpmath``=<arg>`

`-mfpu``=<arg>`

`-mglobal-merge````,` `-mno-global-merge```

Enable merging of globals

`-mhard-float```

`-mhwdiv``=<arg>``,` `--mhwdiv``<arg>``,` `--mhwdiv``=<arg>`

`-miamcu````,` `-mno-iamcu```

Use Intel MCU ABI

`-mimplicit-float````,` `-mno-implicit-float```

`-mimplicit-it``=<arg>`

`-mincremental-linker-compatible````,` `-mno-incremental-linker-compatible```

(integrated-as) Emit an object file which can be used with an incremental linker

`-miphoneos-version-min``=<arg>``,` `-mios-version-min``=<arg>`

`-mips16```

`-mkernel```

`-mldc1-sdc1````,` `-mno-ldc1-sdc1```

`-mlong-calls````,` `-mno-long-calls```

Generate branches with extended addressability, usually via indirect jumps.

`-mmacosx-version-min``=<arg>``,` `-mmacos-version-min``=<arg>`

Set Mac OS X deployment target

`-mmadd4````,` `-mno-madd4```

Enable the generation of 4-operand madd.s, madd.d and related instructions.

`-mmcu``=<arg>`

`-mmicromips````,` `-mno-micromips```

`-mms-bitfields````,` `-mno-ms-bitfields```

Set the default structure layout to be compatible with the Microsoft compiler standard

`-mmsa````,` `-mno-msa```

Enable MSA ASE (MIPS only)

`-mmt````,` `-mno-mt```

Enable MT ASE (MIPS only)

`-mnan``=<arg>`

`-mno-mips16```

`-momit-leaf-frame-pointer````,` `-mno-omit-leaf-frame-pointer```

Omit frame pointer setup for leaf functions

`-moslib``=<arg>`

`-mpie-copy-relocations````,` `-mno-pie-copy-relocations```

Use copy relocations support for PIE builds

`-mqdsp6-compat```

Enable hexagon-qdsp6 backward compatibility

`-mrecip```

`-mrecip``=<arg1>,<arg2>...`

`-mred-zone````,` `-mno-red-zone```

`-mregparm``=<arg>`

`-mrelax-all````,` `-mno-relax-all```

(integrated-as) Relax all machine instructions

`-mrtd````,` `-mno-rtd```

Make StdCall calling convention the default

`-msingle-float```

`-msoft-float````,` `-mno-soft-float```

Use software floating point

`-mstack-alignment``=<arg>`

Set the stack alignment

`-mstack-probe-size``=<arg>`

Set the stack probe size

`-mstackrealign````,` `-mno-stackrealign```

Force realign the stack at entry to every function

`-mthread-model``<arg>`

The thread model to use, e.g. posix, single (posix by default)

`-mthreads<arg>```

`-mthumb````,` `-mno-thumb```

`-mtune``=<arg>`

`-mtvos-version-min``=<arg>``,` `-mappletvos-version-min``=<arg>`

`-municode<arg>```

`-mvx````,` `-mno-vx```

`-mwarn-nonportable-cfstrings````,` `-mno-warn-nonportable-cfstrings```

`-mwatchos-version-min``=<arg>`

`-mwindows<arg>```

`-mx32```

`-mxgot````,` `-mno-xgot```

#### AARCH64

`-ffixed-x18```

Reserve the x18 register (AArch64 only)

`-mfix-cortex-a53-835769````,` `-mno-fix-cortex-a53-835769```

Workaround Cortex-A53 erratum 835769 (AArch64 only)

`-mgeneral-regs-only```

Generate code which only uses the general purpose registers (AArch64 only)

#### AMDGPU

#### ARM

`-ffixed-r9```

Reserve the r9 register (ARM only)

`-mcrc```

Allow use of CRC instructions (ARM only)

`-mexecute-only````,` `-mno-execute-only````,` `-mpure-code```

Disallow generation of data access to code sections (ARM only)

`-mno-movt```

Disallow use of movt/movw pairs (ARM only)

`-mno-neg-immediates```

Disallow converting instructions with negative immediates to their negation or inversion.

`-mnocrc```

Disallow use of CRC instructions (ARM only)

`-mrestrict-it````,` `-mno-restrict-it```

Disallow generation of deprecated IT blocks for ARMv8. It is on by default for ARMv8 Thumb mode.

`-munaligned-access````,` `-mno-unaligned-access```

Allow memory accesses to be unaligned (AArch32/AArch64 only)

#### Hexagon

`-mhvx````,` `-mno-hvx```

Enable Hexagon Vector eXtensions

`-mhvx-double````,` `-mno-hvx-double```

Enable Hexagon Double Vector eXtensions

`-mieee-rnd-near```

#### PowerPC

`-maltivec````,` `-mno-altivec```

`-mcmpb````,` `-mno-cmpb```

`-mcrbits````,` `-mno-crbits```

`-mcrypto````,` `-mno-crypto```

`-mdirect-move````,` `-mno-direct-move```

`-mfloat128````,` `-mno-float128```

`-mfprnd````,` `-mno-fprnd```

`-mhtm````,` `-mno-htm```

`-minvariant-function-descriptors````,` `-mno-invariant-function-descriptors```

`-misel````,` `-mno-isel```

`-mlongcall````,` `-mno-longcall```

`-mmfocrf````,` `-mmfcrf````,` `-mno-mfocrf```

`-mpopcntd````,` `-mno-popcntd```

`-mpower8-vector````,` `-mno-power8-vector```

`-mpower9-vector````,` `-mno-power9-vector```

`-mqpx````,` `-mno-qpx```

`-mvsx````,` `-mno-vsx```

#### WebAssembly

`-msimd128````,` `-mno-simd128```

#### X86

`-m3dnow````,` `-mno-3dnow```

`-m3dnowa````,` `-mno-3dnowa```

`-madx````,` `-mno-adx```

`-maes````,` `-mno-aes```

`-mavx````,` `-mno-avx```

`-mavx2````,` `-mno-avx2```

`-mavx512bw````,` `-mno-avx512bw```

`-mavx512cd````,` `-mno-avx512cd```

`-mavx512dq````,` `-mno-avx512dq```

`-mavx512er````,` `-mno-avx512er```

`-mavx512f````,` `-mno-avx512f```

`-mavx512ifma````,` `-mno-avx512ifma```

`-mavx512pf````,` `-mno-avx512pf```

`-mavx512vbmi````,` `-mno-avx512vbmi```

`-mavx512vl````,` `-mno-avx512vl```

`-mavx512vpopcntdq````,` `-mno-avx512vpopcntdq```

`-mbmi````,` `-mno-bmi```

`-mbmi2````,` `-mno-bmi2```

`-mclflushopt````,` `-mno-clflushopt```

`-mclwb````,` `-mno-clwb```

`-mclzero````,` `-mno-clzero```

`-mcx16````,` `-mno-cx16```

`-mf16c````,` `-mno-f16c```

`-mfma````,` `-mno-fma```

`-mfma4````,` `-mno-fma4```

`-mfsgsbase````,` `-mno-fsgsbase```

`-mfxsr````,` `-mno-fxsr```

`-mlwp````,` `-mno-lwp```

`-mlzcnt````,` `-mno-lzcnt```

`-mmmx````,` `-mno-mmx```

`-mmovbe````,` `-mno-movbe```

`-mmpx````,` `-mno-mpx```

`-mmwaitx````,` `-mno-mwaitx```

`-mpclmul````,` `-mno-pclmul```

`-mpku````,` `-mno-pku```

`-mpopcnt````,` `-mno-popcnt```

`-mprefetchwt1````,` `-mno-prefetchwt1```

`-mprfchw````,` `-mno-prfchw```

`-mrdrnd````,` `-mno-rdrnd```

`-mrdseed````,` `-mno-rdseed```

`-mrtm````,` `-mno-rtm```

`-msgx````,` `-mno-sgx```

`-msha````,` `-mno-sha```

`-msse````,` `-mno-sse```

`-msse2````,` `-mno-sse2```

`-msse3````,` `-mno-sse3```

`-msse4.1````,` `-mno-sse4.1```

`-msse4.2````,` `-mno-sse4.2````,` `-msse4```

`-msse4a````,` `-mno-sse4a```

`-mssse3````,` `-mno-ssse3```

`-mtbm````,` `-mno-tbm```

`-mx87````,` `-m80387````,` `-mno-x87```

`-mxop````,` `-mno-xop```

`-mxsave````,` `-mno-xsave```

`-mxsavec````,` `-mno-xsavec```

`-mxsaveopt````,` `-mno-xsaveopt```

`-mxsaves````,` `-mno-xsaves```

### Optimization level

Flags controlling how much optimization should be performed.

`-O<arg>````,` `-O``(equivalent to -O2)``,` `--optimize````,` `--optimize``=<arg>`

`-Ofast<arg>```

### Debug information generation

Flags controlling how much and what kind of debug information should be generated.

#### Kind and level of debug information

`-g````,` `--debug````,` `--debug``=<arg>`

Generate source-level debug information

`-gdwarf-2```

Generate source-level debug information with dwarf version 2

`-gdwarf-3```

Generate source-level debug information with dwarf version 3

`-gdwarf-4````,` `-gdwarf```

Generate source-level debug information with dwarf version 4

`-gdwarf-5```

Generate source-level debug information with dwarf version 5

`-gfull```

`-gused```

##### Debug level

`-g0```

`-g2```

`-g3```

`-ggdb0```

`-ggdb1```

`-ggdb2```

`-ggdb3```

`-gline-tables-only````,` `-g1````,` `-gmlt```

Emit debug line number tables only

`-gmodules```

Generate debug info with external references to clang modules or precompiled headers

##### Debugger to tune debug information for

`-ggdb```

`-glldb```

`-gsce```

#### Debug information flags

`-gcolumn-info````,` `-gno-column-info```

`-gdwarf-aranges```

`-ggnu-pubnames```

`-grecord-gcc-switches````,` `-gno-record-gcc-switches```

`-gsplit-dwarf```

`-gstrict-dwarf````,` `-gno-strict-dwarf```

`-gz```

DWARF debug sections compression type

`-gz``=<arg>`

DWARF debug sections compression type

## Static analyzer flags

Flags controlling the behavior of the Clang Static Analyzer.

`-Xanalyzer``<arg>`

Pass <arg> to the static analyzer

## Fortran compilation flags

Flags that will be passed onto the `gfortran` compiler when Clang is given a Fortran input.

`-A<arg>````,` `--assert``<arg>``,` `--assert``=<arg>`

`-A-<arg>```

`-J<arg>```

`-cpp```

`-faggressive-function-elimination````,` `-fno-aggressive-function-elimination```

`-falign-commons````,` `-fno-align-commons```

`-fall-intrinsics````,` `-fno-all-intrinsics```

`-fautomatic````,` `-fno-automatic```

`-fbackslash````,` `-fno-backslash```

`-fbacktrace````,` `-fno-backtrace```

`-fblas-matmul-limit``=<arg>`

`-fbounds-check````,` `-fno-bounds-check```

`-fcheck-array-temporaries````,` `-fno-check-array-temporaries```

`-fcheck``=<arg>`

`-fcoarray``=<arg>`

`-fconvert``=<arg>`

`-fcray-pointer````,` `-fno-cray-pointer```

`-fd-lines-as-code````,` `-fno-d-lines-as-code```

`-fd-lines-as-comments````,` `-fno-d-lines-as-comments```

`-fdefault-double-8````,` `-fno-default-double-8```

`-fdefault-integer-8````,` `-fno-default-integer-8```

`-fdefault-real-8````,` `-fno-default-real-8```

`-fdollar-ok````,` `-fno-dollar-ok```

`-fdump-fortran-optimized````,` `-fno-dump-fortran-optimized```

`-fdump-fortran-original````,` `-fno-dump-fortran-original```

`-fdump-parse-tree````,` `-fno-dump-parse-tree```

`-fexternal-blas````,` `-fno-external-blas```

`-ff2c````,` `-fno-f2c```

`-ffixed-form````,` `-fno-fixed-form```

`-ffixed-line-length-<arg>```

`-ffpe-trap``=<arg>`

`-ffree-form````,` `-fno-free-form```

`-ffree-line-length-<arg>```

`-ffrontend-optimize````,` `-fno-frontend-optimize```

`-fimplicit-none````,` `-fno-implicit-none```

`-finit-character``=<arg>`

`-finit-integer``=<arg>`

`-finit-local-zero````,` `-fno-init-local-zero```

`-finit-logical``=<arg>`

`-finit-real``=<arg>`

`-finteger-4-integer-8````,` `-fno-integer-4-integer-8```

`-fintrinsic-modules-path````,` `-fno-intrinsic-modules-path```

`-fmax-array-constructor``=<arg>`

`-fmax-errors``=<arg>`

`-fmax-identifier-length````,` `-fno-max-identifier-length```

`-fmax-stack-var-size``=<arg>`

`-fmax-subrecord-length``=<arg>`

`-fmodule-private````,` `-fno-module-private```

`-fpack-derived````,` `-fno-pack-derived```

`-fprotect-parens````,` `-fno-protect-parens```

`-frange-check````,` `-fno-range-check```

`-freal-4-real-10````,` `-fno-real-4-real-10```

`-freal-4-real-16````,` `-fno-real-4-real-16```

`-freal-4-real-8````,` `-fno-real-4-real-8```

`-freal-8-real-10````,` `-fno-real-8-real-10```

`-freal-8-real-16````,` `-fno-real-8-real-16```

`-freal-8-real-4````,` `-fno-real-8-real-4```

`-frealloc-lhs````,` `-fno-realloc-lhs```

`-frecord-marker``=<arg>`

`-frecursive````,` `-fno-recursive```

`-frepack-arrays````,` `-fno-repack-arrays```

`-fsecond-underscore````,` `-fno-second-underscore```

`-fsign-zero````,` `-fno-sign-zero```

`-fstack-arrays````,` `-fno-stack-arrays```

`-funderscoring````,` `-fno-underscoring```

`-fwhole-file````,` `-fno-whole-file```

`-nocpp```

`-static-libgfortran```

## Linker flags

Flags that are passed on to the linker

`-L<dir>````,` `--library-directory``<arg>``,` `--library-directory``=<arg>`

Add directory to library search path

`-Mach```

`-T<script>```

Specify <script> as linker script

`-Tbss<addr>```

Set starting address of BSS to <addr>

`-Tdata<addr>```

Set starting address of BSS to <addr>

`-Ttext<addr>```

Set starting address of BSS to <addr>

`-Wl,<arg>,<arg2>...```

Pass the comma separated arguments in <arg> to the linker

`-X```

`-Xlinker``<arg>``,` `--for-linker``<arg>``,` `--for-linker``=<arg>`

Pass <arg> to the linker

`-Z```

`-e<arg>````,` `--entry```

`-filelist``<arg>`

`-l<arg>```

`-r```

`-rpath``<arg>`

`-s```

`-t```

`-u<arg>````,` `--force-link``<arg>``,` `--force-link``=<arg>`

`-undef```

undef all system defines

`-undefined<arg>````,` `--no-undefined```

`-z``<arg>`

Pass -z <arg> to the linker