..
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  NOTE: This file is automatically generated by running clang-tblgen
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=====================================
Clang command line argument reference
=====================================
.. contents::
   :local:

Introduction
============

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


.. program:: clang
.. option:: -B<prefix>, --prefix <arg>, --prefix=<arg>

Search $prefix$file for executables, libraries, and data files. If $prefix is a directory, search $prefix/$file

.. option:: -F<arg>

Add directory to framework include search path

.. option:: -K

.. option:: -ObjC

Treat source input files as Objective-C inputs

.. program:: clang1
.. option:: -ObjC++
.. program:: clang

Treat source input files as Objective-C++ inputs

.. option:: -Qn, -fno-ident

Do not emit metadata containing compiler name and version

.. option:: -Qunused-arguments

Don't emit warning for unused driver arguments

.. option:: -Qy, -fident

Emit metadata containing compiler name and version

.. option:: -Wa,<arg>,<arg2>...

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

.. option:: -Wlarge-by-value-copy=<arg>

.. option:: -Xarch_<arch> <arg>

Specifies that the argument should only be used if the compilation
  target matches the specified architecture. This can be used with the target
  CPU, triple architecture, or offloading host and device. It is most useful
  for separating behavior undesirable on one of the targets when combining many
  compilation jobs, as is common with offloading. For example, -Xarch_x86_64,
  -Xarch_gfx90a, and -Xarch_device are all valid selectors. -Xarch_device will
  forward the argument to the offloading device while -Xarch_host will target
  the host system, which can be used to suppress incompatible GPU arguments.

.. program:: clang1
.. option:: -Xarch_device <arg>
.. program:: clang

Pass <arg> to device compilation in the offloading toolchain

.. program:: clang2
.. option:: -Xarch_host <arg>
.. program:: clang

Pass <arg> to host compilation in the offloading toolchain

.. option:: -Xcuda-fatbinary <arg>

Pass <arg> to fatbinary invocation

.. option:: -Xcuda-ptxas <arg>

Pass <arg> to the ptxas assembler

.. option:: -alias_list <arg>

.. option:: -all_load

.. option:: -allowable_client <arg>

.. option:: --analyze

Run the static analyzer

.. option:: --analyzer-no-default-checks

.. option:: --analyzer-output<arg>

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

.. option:: -arch <arg>

.. program:: clang1
.. option:: -arch_errors_fatal
.. program:: clang

.. program:: clang2
.. option:: -arch_only <arg>
.. program:: clang

.. option:: --autocomplete=<arg>

.. option:: -bind_at_load

.. option:: -bundle

.. program:: clang1
.. option:: -bundle_loader <arg>
.. program:: clang

.. option:: -clangir-disable-passes

Disable CIR transformations pipeline

.. option:: -clangir-disable-verifier

ClangIR: Disable MLIR module verifier

.. option:: -clangir-enable-idiom-recognizer

ClangIR: Enable Idiom Recognizer pass

.. option:: -client_name<arg>

.. option:: -compatibility_version<arg>

.. option:: --config=<file>, --config <arg>

Specify configuration file

.. option:: --constant-cfstrings

.. option:: --cstdlib=<arg>, --cstdlib <arg>

C standard library to use. <arg> must be 'newlib', 'picolibc', 'llvm-libc' or 'system'.

.. option:: -current_version<arg>

.. option:: -darwin-target-variant <arg>

Generate code for an additional runtime variant of the deployment target

.. option:: -darwin-target-variant-triple <arg>

Specify the darwin target variant triple

.. option:: -dead_strip

.. option:: -dependency-dot <arg>

Filename to write DOT-formatted header dependencies to

.. option:: -dependency-file <arg>

Filename (or -) to write dependency output to

.. option:: -dsym-dir<dir>

Directory to output dSYM's (if any) to

.. option:: -dumpdir <dumppfx>

Use <dumpfpx> as a prefix to form auxiliary and dump file names

.. option:: -dumpmachine

Display the compiler's target processor

.. option:: -dumpversion

Display the version of the compiler

.. option:: --dyld-prefix=<arg>, --dyld-prefix <arg>

.. option:: -dylib_file <arg>

.. option:: -dylinker

.. program:: clang1
.. option:: -dylinker_install_name<arg>
.. program:: clang

.. option:: -dynamic

.. option:: -dynamiclib

.. option:: -emit-ast

Emit Clang AST files for source inputs

.. option:: --emit-extension-symbol-graphs

Generate additional symbol graphs for extended modules.

.. option:: --emit-static-lib

Enable linker job to emit a static library.

.. option:: -emit-symbol-graph

Generate Extract API information as a side effect of compilation.

.. option:: --end-no-unused-arguments

Start emitting warnings for unused driver arguments

.. option:: -exported_symbols_list <arg>

.. option:: --extract-api-ignores=<arg1>,<arg2>...

Comma separated list of files containing a new line separated list of API symbols to ignore when extracting API information.

.. option:: -faligned-new=<arg>

.. option:: -fautomatic

.. option:: -fcheck-new, -fno-check-new

Do not assume C++ operator new may not return NULL

.. option:: -fconvergent-functions, -fno-convergent-functions

Assume all functions may be convergent.

.. option:: -fcx-fortran-rules, -fno-cx-fortran-rules

Range reduction is enabled for complex arithmetic operations.

.. option:: -fcx-limited-range, -fno-cx-limited-range

Basic algebraic expansions of complex arithmetic operations involving are enabled.

.. option:: -ffinite-math-only, -fno-finite-math-only

Allow floating-point optimizations that assume arguments and results are not NaNs or +-inf. This defines the \\_\\_FINITE\\_MATH\\_ONLY\\_\\_ preprocessor macro.

.. option:: -fimplicit-modules-lock-timeout=<seconds>

Time to wait on an implicit module lock before timing out

.. option:: -flat_namespace

.. option:: -fmodule-output

Save intermediate module file results when compiling a standard C++ module unit.

.. program:: clang1
.. option:: -fmodule-output=<arg>
.. program:: clang

Save intermediate module file results when compiling a standard C++ module unit.

.. option:: -fmodules-embed-all-files<arg>

Embed the contents of all files read by this compilation into the produced module file.

.. option:: -fmodules-reduced-bmi, -fexperimental-modules-reduced-bmi, -fno-modules-reduced-bmi

Generate the reduced BMI

.. option:: -fmultilib-flag=<arg>, --fmultilib-flag=<arg>

.. option:: -force_cpusubtype_ALL

.. program:: clang1
.. option:: -force_flat_namespace
.. program:: clang

.. program:: clang2
.. option:: -force_load <arg>
.. program:: clang

.. option:: -fplugin-arg-<name>-<arg>

Pass <arg> to plugin <name>

.. option:: -framework <arg>

.. option:: -frtlib-add-rpath, -fno-rtlib-add-rpath, --no-offload-add-rpath, --offload-add-rpath

Add -rpath with architecture-specific resource directory to the linker flags. When --hip-link is specified, also add -rpath with HIP runtime library directory to the linker flags

.. option:: -fsanitize-kcfi-hash=<arg>

Select hash algorithm for KCFI type IDs (xxHash64, FNV-1a). <arg> must be 'xxHash64' or 'FNV-1a'.

.. option:: -fsanitize-system-ignorelist=<arg>

Path to system ignorelist file for sanitizers

.. option:: -fsanitize-undefined-ignore-overflow-pattern=<arg1>,<arg2>...

Specify the overflow patterns to exclude from arithmetic sanitizer instrumentation. <arg> must be 'none', 'all', 'add-unsigned-overflow-test', 'add-signed-overflow-test', 'negated-unsigned-const' or 'unsigned-post-decr-while'.

.. option:: -fshow-skipped-includes

#include files may be "skipped" due to include guard optimization
             or #pragma once. This flag makes -H show also such includes.

.. option:: -fsystem-module

Build this module as a system module. Only used with -emit-module

.. option:: --gcc-install-dir=<arg>

Use GCC installation in the specified directory. The directory ends with path components like 'lib{,32,64}/gcc{,-cross}/$triple/$version'. Note: executables (e.g. ld) used by the compiler are not overridden by the selected GCC installation

.. option:: --gcc-toolchain=<arg>

Specify a directory where Clang can find 'include' and 'lib{,32,64}/gcc{,-cross}/$triple/$version'. Clang will use the GCC installation with the largest version

.. option:: --gcc-triple=<arg>

Search for the GCC installation with the specified triple.

.. option:: -gen-reproducer=<arg>, -fno-crash-diagnostics (equivalent to -gen-reproducer=off)

Emit reproducer on (option: off, crash (default), error, always)

.. option:: -gpulibc

Link the LLVM C Library for GPUs

.. option:: -headerpad_max_install_names<arg>

.. option:: -help, --help

Display available options

.. option:: --help-hidden

Display help for hidden options

.. option:: -image_base <arg>

.. option:: -init <arg>

.. option:: -install_name <arg>

.. option:: -interface-stub-version=<arg>

.. option:: -keep_private_externs

.. option:: -lazy_framework <arg>

.. program:: clang1
.. option:: -lazy_library <arg>
.. program:: clang

.. option:: -m3dnow, -mno-3dnow

.. option:: -m3dnowa, -mno-3dnowa

.. option:: -mllvm <arg>, -mllvm=<arg>

Additional arguments to forward to LLVM's option processing

.. option:: -mmlir <arg>

Additional arguments to forward to MLIR's option processing

.. option:: -module-dependency-dir <arg>

Directory to dump module dependencies to

.. option:: -mtvos-simulator-version-min=<arg>, -mappletvsimulator-version-min=<arg>

.. option:: -multi-lib-config=<file>, --multi-lib-config=<file>

Path to the YAML configuration file to be used for multilib selection

.. option:: -multi_module

.. option:: -multiply_defined <arg>

.. program:: clang1
.. option:: -multiply_defined_unused <arg>
.. program:: clang

.. option:: -mzos-hlq-clang=<ClangHLQ>

High level qualifier for z/OS C++RT side deck datasets

.. option:: -mzos-hlq-csslib=<CsslibHLQ>

High level qualifier for z/OS CSSLIB dataset

.. option:: -mzos-hlq-le=<LeHLQ>

High level qualifier for z/OS Language Environment datasets

.. option:: -mzos-sys-include=<SysInclude>

Path to system headers on z/OS

.. option:: --no-default-config

Disable loading default configuration files

.. option:: -no-integrated-cpp, --no-integrated-cpp

.. option:: --no-xcselect

Disable xcselect SDK injection on macOS

.. option:: -no_dead_strip_inits_and_terms

.. option:: -nodefaultlibs

.. option:: -nodriverkitlib

.. option:: -nofixprebinding

.. option:: -nogpulibc

.. option:: -nolibc

.. option:: -nomultidefs

.. option:: -nopie

.. option:: -noprebind

.. option:: -noprofilelib

.. option:: -noseglinkedit

.. option:: -nostdlib++

.. option:: -o<file>, --output <arg>, --output=<arg>

Write output to <file>

.. option:: -object

.. option:: -object-file-name=<file>, -object-file-name <arg>

Set the output <file> for debug infos

.. option:: --offloadlib, --no-offloadlib

Link device libraries for GPU device compilation

.. option:: -p, --profile

Enable mcount instrumentation with prof

.. option:: -pagezero_size<arg>

.. option:: -pg

Enable mcount instrumentation

.. option:: -pipe, --pipe

Use pipes between commands, when possible

.. option:: -prebind

.. program:: clang1
.. option:: -prebind_all_twolevel_modules
.. program:: clang

.. option:: -preload

.. option:: --pretty-sgf

Emit pretty printed symbol graphs

.. option:: --print-diagnostic-categories

.. option:: -print-diagnostic-options, --print-diagnostic-options

Print all of Clang's warning options

.. option:: -print-effective-triple, --print-effective-triple

Print the effective target triple

.. option:: -print-enabled-extensions, --print-enabled-extensions

Print the extensions enabled by the given target and -march/-mcpu options. (AArch64 and RISC-V only)

.. option:: -print-file-name=<file>, --print-file-name=<file>, --print-file-name <arg>

Print the full library path of <file>

.. option:: -print-ivar-layout

Enable Objective-C Ivar layout bitmap print trace

.. option:: -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")

.. option:: -print-library-module-manifest-path, --print-library-module-manifest-path

Print the path for the C++ Standard library module manifest

.. option:: -print-multi-directory, --print-multi-directory

.. option:: -print-multi-flags-experimental, --print-multi-flags-experimental

Print the flags used for selecting multilibs (experimental)

.. option:: -print-multi-lib, --print-multi-lib

.. option:: -print-prog-name=<name>, --print-prog-name=<name>, --print-prog-name <arg>

Print the full program path of <name>

.. option:: -print-resource-dir, --print-resource-dir

Print the resource directory pathname

.. option:: -print-rocm-search-dirs, --print-rocm-search-dirs

Print the paths used for finding ROCm installation

.. option:: -print-runtime-dir, --print-runtime-dir

Print the directory pathname containing Clang's runtime libraries

.. option:: -print-search-dirs, --print-search-dirs

Print the paths used for finding libraries and programs

.. option:: -print-supported-extensions, --print-supported-extensions

Print supported -march extensions (RISC-V, AArch64 and ARM only)

.. option:: -print-target-triple, --print-target-triple

Print the normalized target triple

.. option:: -print-targets, --print-targets

Print the registered targets

.. option:: -private_bundle

.. option:: --product-name=<arg>

.. option:: -pthread, -no-pthread

Support POSIX threads in generated code

.. option:: -pthreads

.. option:: -read_only_relocs <arg>

.. option:: -reexport-l<arg>

.. option:: -reexport_framework <arg>

.. program:: clang1
.. option:: -reexport_library<arg>
.. program:: clang

.. option:: -relocatable-pch, --relocatable-pch

Whether to build a relocatable precompiled header

.. option:: -remap

.. option:: -resource-dir <arg>, -resource-dir=<arg>

The directory which holds the compiler resource files

.. option:: -rewrite-legacy-objc

Rewrite Legacy Objective-C source to C++

.. option:: -rtlib=<arg>, --rtlib=<arg>, --rtlib <arg>

Compiler runtime library to use

.. option:: -save-stats=<arg>, --save-stats=<arg>, -save-stats (equivalent to -save-stats=cwd), --save-stats (equivalent to -save-stats=cwd)

Save llvm statistics.

.. option:: -save-temps=<arg>, --save-temps=<arg>, -save-temps (equivalent to -save-temps=cwd), --save-temps (equivalent to -save-temps=cwd)

Save intermediate compilation results. <arg> can be set to 'cwd' for current working directory, or 'obj' which will save temporary files in the same directory as the final output file

.. option:: -sectalign <arg1> <arg2> <arg3>

.. option:: -sectcreate <arg1> <arg2> <arg3>

.. option:: -sectobjectsymbols <arg1> <arg2>

.. option:: -sectorder <arg1> <arg2> <arg3>

.. option:: -seg1addr<arg>

.. option:: -seg_addr_table <arg>

.. program:: clang1
.. option:: -seg_addr_table_filename <arg>
.. program:: clang

.. option:: -segaddr <arg1> <arg2>

.. option:: -segcreate <arg1> <arg2> <arg3>

.. option:: -seglinkedit

.. option:: -segprot <arg1> <arg2> <arg3>

.. option:: -segs_read_<arg>

.. program:: clang1
.. option:: -segs_read_only_addr <arg>
.. program:: clang

.. program:: clang2
.. option:: -segs_read_write_addr <arg>
.. program:: clang

.. option:: -serialize-diagnostics <arg>, --serialize-diagnostics <arg>

Serialize compiler diagnostics to a file

.. option:: -shared-libgcc

.. option:: -shared-libsan, -shared-libasan

Dynamically link the sanitizer runtime

.. option:: -single_module

.. option:: --start-no-unused-arguments

Don't emit warnings about unused arguments for the following arguments

.. option:: -static-libclosure

Generate code for statically linking libclosure (BlocksRuntime)

.. option:: -static-libgcc

.. option:: -static-libsan, -static-libasan

Statically link the sanitizer runtime (Not supported for ASan, TSan or UBSan on darwin)

.. option:: -static-libstdc++

.. option:: -static-openmp

Use the static host OpenMP runtime while linking.

.. option:: -std-default=<arg>

.. option:: -stdlib=<arg>, --stdlib=<arg>, --stdlib <arg>

C++ standard library to use. <arg> must be 'libc++', 'libstdc++' or 'platform'.

.. option:: -sub_library<arg>

.. program:: clang1
.. option:: -sub_umbrella<arg>
.. program:: clang

.. option:: --symbol-graph-dir=<arg>

Directory in which to emit symbol graphs.

.. option:: --sysroot=<arg>, --sysroot <arg>

.. option:: --target-help

.. option:: --target=<arg>, -target <arg>

Generate code for the given target

.. option:: -time

Time individual commands

.. option:: -traditional, --traditional

.. option:: -traditional-cpp, --traditional-cpp

Enable some traditional CPP emulation

.. option:: -twolevel_namespace

.. program:: clang1
.. option:: -twolevel_namespace_hints
.. program:: clang

.. option:: -umbrella <arg>

.. option:: -unexported_symbols_list <arg>

.. option:: -unwindlib=<arg>, --unwindlib=<arg>

Unwind library to use. <arg> must be 'libgcc', 'libunwind' or 'platform'.

.. option:: -v, --verbose

Show commands to run and use verbose output

.. option:: --verify-debug-info

Verify the binary representation of debug output

.. option:: --version

Print version information

.. option:: -vfsoverlay<arg>, --vfsoverlay<arg>

Overlay the virtual filesystem described by file over the real file system. Additionally, pass this overlay file to the linker if it supports it

.. option:: -w, --no-warnings

Suppress all warnings

.. option:: -weak-l<arg>

.. option:: -weak_framework <arg>

.. program:: clang1
.. option:: -weak_library <arg>
.. program:: clang

.. program:: clang2
.. option:: -weak_reference_mismatches <arg>
.. program:: clang

.. option:: -whatsloaded

.. option:: -why_load, -whyload

.. option:: -working-directory <arg>, -working-directory=<arg>

Resolve file paths relative to the specified directory

.. option:: -x<language>, --language <arg>, --language=<arg>

Treat subsequent input files as having type <language>

.. option:: -y<arg>

Actions
=======
The action to perform on the input.

.. option:: -E, --preprocess

Only run the preprocessor

.. option:: -S, --assemble

Only run preprocess and compilation steps

.. option:: -c, --compile

Only run preprocess, compile, and assemble steps

.. option:: -emit-cir

Build ASTs and then lower to ClangIR

.. option:: -emit-interface-stubs

Generate Interface Stub Files.

.. option:: -emit-llvm

Use the LLVM representation for assembler and object files

.. option:: -emit-merged-ifs

Generate Interface Stub Files, emit merged text not binary.

.. option:: -extract-api

Extract API information

.. option:: -fdriver-only

Only run the driver.

.. option:: -fsyntax-only

Run the preprocessor, parser and semantic analysis stages

.. option:: -module-file-info

Provide information about a particular module file

.. option:: --precompile

Only precompile the input

.. option:: --precompile-reduced-bmi

Only precompile the input as a reduced BMI

.. option:: -rewrite-objc

Rewrite Objective-C source to C++

.. option:: -verify-pch

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

Compilation options
===================

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

.. option:: -Xassembler <arg>

Pass <arg> to the assembler

.. option:: -Xclang <arg>, -Xclang=<arg>

Pass <arg> to clang -cc1

.. option:: -Xclangas <arg>, -Xclangas=<arg>

Pass <arg> to clang -cc1as

.. option:: -Xopenmp-target <arg>

Pass <arg> to the target offloading toolchain.

.. program:: clang1
.. option:: -Xopenmp-target=<triple> <arg>
.. program:: clang

Pass <arg> to the target offloading toolchain identified by <triple>.

.. option:: -ansi, --ansi

.. option:: -fallow-runtime-check-skip-hot-cutoff=<arg>

Exclude __builtin_allow_runtime_check for the top hottest code responsible for the given fraction of PGO counters (0.0 \[default\] = skip none; 1.0 = skip all). Argument format: <value>

.. option:: -fapinotes, -fno-apinotes

Enable external API notes support

.. option:: -fapinotes-modules, -fno-apinotes-modules

Enable module-based external API notes support

.. option:: -fapinotes-swift-version=<version>

Specify the Swift version to use when filtering API notes

.. option:: -fc++-abi=<arg>

C++ ABI to use. This will override the target C++ ABI.

.. option:: -fclang-abi-compat=<version>

Attempt to match the ABI of Clang <version>. <version> must be '<major>.<minor>' or 'latest'.

.. option:: -fcomment-block-commands=<arg>,<arg2>...

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

.. option:: -fcomplete-member-pointers, -fno-complete-member-pointers

Require member pointer base types to be complete if they would be significant under the Microsoft ABI

.. option:: -fcrash-diagnostics-dir=<dir>

Put crash-report files in <dir>

.. option:: -fcrash-diagnostics-tar=<path>

Put crash-report tarball at <path>

.. option:: -fcrash-diagnostics=<arg>, -fcrash-diagnostics (equivalent to -fcrash-diagnostics=compiler)

Set level of crash diagnostic reporting, (option: off, compiler, all)

.. option:: -fdeclspec, -fno-declspec

Allow __declspec as a keyword

.. option:: -fdepfile-entry=<arg>

.. option:: -fdiagnostics-fixit-info, -fno-diagnostics-fixit-info

.. option:: -fdiagnostics-format=<arg>

.. option:: -fdiagnostics-parseable-fixits

Print fix-its in machine parseable form

.. option:: -fdiagnostics-print-source-range-info

Print source range spans in numeric form

.. option:: -fdiagnostics-show-category=<arg>

.. option:: -fdiscard-value-names, -fno-discard-value-names

Discard value names in LLVM IR

.. option:: -fexperimental-relative-c++-abi-vtables, -fno-experimental-relative-c++-abi-vtables

Use the experimental C++ class ABI for classes with virtual tables

.. option:: -fexperimental-strict-floating-point

Enables the use of non-default rounding modes and non-default exception handling on targets that are not currently ready.

.. option:: -ffine-grained-bitfield-accesses, -fno-fine-grained-bitfield-accesses

Use separate accesses for consecutive bitfield runs with legal widths and alignments.

.. option:: -fglobal-isel, -fexperimental-isel, -fno-global-isel

Enables the global instruction selector

.. option:: -finline-functions, -fno-inline-functions

Inline suitable functions

.. option:: -finline-hint-functions

Inline functions which are (explicitly or implicitly) marked inline

.. option:: -fno-sanitize-ignorelist

Don't use ignorelist file for sanitizers

.. option:: -fparse-all-comments

.. option:: -frandomize-layout-seed-file=<file>

File holding the seed used by the randomize structure layout feature

.. option:: -frandomize-layout-seed=<seed>

The seed used by the randomize structure layout feature

.. option:: -fsanitize-address-destructor=<arg>

Set the kind of module destructors emitted by AddressSanitizer instrumentation. These destructors are emitted to unregister instrumented global variables when code is unloaded (e.g. via \`dlclose()\`). <arg> must be 'none' or 'global'.

.. option:: -fsanitize-address-field-padding=<arg>

Level of field padding for AddressSanitizer

.. option:: -fsanitize-address-globals-dead-stripping, -fno-sanitize-address-globals-dead-stripping

Enable linker dead stripping of globals in AddressSanitizer

.. option:: -fsanitize-address-outline-instrumentation, -fno-sanitize-address-outline-instrumentation

Always generate function calls for address sanitizer instrumentation

.. option:: -fsanitize-address-poison-custom-array-cookie, -fno-sanitize-address-poison-custom-array-cookie

Enable "poisoning" array cookies when allocating arrays with a
custom operator new\[\] in Address Sanitizer, preventing accesses to the
cookies from user code. An array cookie is a small implementation-defined
header added to certain array allocations to record metadata such as the
length of the array. Accesses to array cookies from user code are technically
allowed by the standard but are more likely to be the result of an
out-of-bounds array access.

An operator new\[\] is "custom" if it is not one of the allocation functions
provided by the C++ standard library. Array cookies from non-custom allocation
functions are always poisoned.

.. option:: -fsanitize-address-use-after-return=<mode>

Select the mode of detecting stack use-after-return in AddressSanitizer. <mode> must be 'never', 'runtime' or 'always'.

.. option:: -fsanitize-address-use-after-scope, -fno-sanitize-address-use-after-scope

Enable use-after-scope detection in AddressSanitizer

.. option:: -fsanitize-address-use-odr-indicator, -fno-sanitize-address-use-odr-indicator

Enable ODR indicator globals to avoid false ODR violation reports in partially sanitized programs at the cost of an increase in binary size

.. option:: -fsanitize-alloc-token-extended, -fno-sanitize-alloc-token-extended

Enable extended coverage to custom allocation functions

.. option:: -fsanitize-alloc-token-fast-abi, -fno-sanitize-alloc-token-fast-abi

Use the AllocToken fast ABI

.. option:: -fsanitize-annotate-debug-info=<arg1>,<arg2>..., -fno-sanitize-annotate-debug-info=<arg1>,<arg2>..., -fsanitize-annotate-debug-info (equivalent to -fsanitize-annotate-debug-info=all)

Annotate sanitizer instrumentation with extra debug info for the specified sanitizers, if supported

.. option:: -fsanitize-cfi-canonical-jump-tables, -fno-sanitize-cfi-canonical-jump-tables

Make the jump table addresses canonical in the symbol table

.. option:: -fsanitize-cfi-cross-dso, -fno-sanitize-cfi-cross-dso

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

.. option:: -fsanitize-cfi-icall-experimental-normalize-integers

Normalize integers in CFI indirect call type signature checks

.. option:: -fsanitize-cfi-icall-generalize-pointers

Generalize pointers in CFI indirect call type signature checks

.. option:: -fsanitize-handler-preserve-all-regs, -fno-sanitize-handler-preserve-all-regs

Enable handlers with preserve_all calling convention

.. option:: -fsanitize-hwaddress-abi=<arg>

Select the HWAddressSanitizer ABI to target (interceptor or platform, default interceptor). This option is currently unused.

.. option:: -fsanitize-hwaddress-experimental-aliasing, -fno-sanitize-hwaddress-experimental-aliasing

Enable aliasing mode in HWAddressSanitizer

.. option:: -fsanitize-ignore-for-ubsan-feature=<check>,<arg2>...

Prevents \`__has_feature(undefined_behavior_sanitizer)\` from evaluating true for these UBSan checks. See user manual for available UBSan checks

.. option:: -fsanitize-ignorelist=<arg>

Path to ignorelist file for sanitizers

.. option:: -fsanitize-kcfi-arity

Embed function arity information into the KCFI patchable function prefix

.. option:: -fsanitize-link-c++-runtime, -fno-sanitize-link-c++-runtime

.. option:: -fsanitize-link-runtime, -fno-sanitize-link-runtime

.. option:: -fsanitize-memory-track-origins=<arg>, -fsanitize-memory-track-origins (equivalent to -fsanitize-memory-track-origins=2)

Enable origins tracking in MemorySanitizer

.. option:: -fsanitize-memory-use-after-dtor, -fno-sanitize-memory-use-after-dtor

Enable use-after-destroy detection in MemorySanitizer

.. option:: -fsanitize-memtag-mode=<arg>

Set default MTE mode to 'sync' (default) or 'async'

.. option:: -fsanitize-merge=<arg1>,<arg2>..., -fno-sanitize-merge=<arg1>,<arg2>..., -fsanitize-merge (equivalent to -fsanitize-merge=all)

Allow compiler to merge handlers for specified sanitizers

.. option:: -fsanitize-minimal-runtime, -fno-sanitize-minimal-runtime

.. option:: -fsanitize-recover=<arg1>,<arg2>..., -fno-sanitize-recover=<arg1>,<arg2>..., -fsanitize-recover (equivalent to -fsanitize-recover=all)

Enable recovery for specified sanitizers

.. option:: -fsanitize-skip-hot-cutoff=<arg1>,<arg2>...

Exclude sanitization for the top hottest code responsible for the given fraction of PGO counters (0.0 \[default\] = skip none; 1.0 = skip all). Argument format: <sanitizer1>=<value1>,<sanitizer2>=<value2>,...

.. option:: -fsanitize-stats, -fno-sanitize-stats

Enable sanitizer statistics gathering.

.. option:: -fsanitize-thread-atomics, -fno-sanitize-thread-atomics

Enable atomic operations instrumentation in ThreadSanitizer (default)

.. option:: -fsanitize-thread-func-entry-exit, -fno-sanitize-thread-func-entry-exit

Enable function entry/exit instrumentation in ThreadSanitizer (default)

.. option:: -fsanitize-thread-memory-access, -fno-sanitize-thread-memory-access

Enable memory access instrumentation in ThreadSanitizer (default)

.. option:: -fsanitize-trap-loop, -fno-sanitize-trap-loop

Use infinite loops in trapping mode

.. option:: -fsanitize-trap=<arg1>,<arg2>..., -fno-sanitize-trap=<arg1>,<arg2>..., -fsanitize-trap (equivalent to -fsanitize-trap=all), -fsanitize-undefined-trap-on-error (equivalent to -fsanitize-trap=undefined)

Enable trapping for specified sanitizers

.. option:: -fsanitize-type-outline-instrumentation, -fno-sanitize-type-outline-instrumentation

Always generate function calls for type sanitizer instrumentation

.. option:: -fsanitize-undefined-strip-path-components=<number>

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

.. option:: -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

.. option:: -fswift-version-independent-apinotes, -fno-swift-version-independent-apinotes

Enable version-independent external API notes support

.. option:: -fuse-lipo=<arg>

.. option:: -fverify-intermediate-code, -fno-verify-intermediate-code

Enable verification of LLVM IR

.. option:: -mno-fmv

Disable function multiversioning

.. option:: -moutline-atomics, -mno-outline-atomics

Generate local calls to out-of-line atomic operations

.. option:: --param <arg>, --param=<arg>

.. option:: -print-supported-cpus, --print-supported-cpus, -mcpu=help, -mtune=help

Print supported cpu models for the given target (if target is not specified,it will print the supported cpus for the default target)

.. option:: -std=<arg>, --std=<arg>, --std <arg>

Language standard to compile for

Preprocessor options
~~~~~~~~~~~~~~~~~~~~

Flags controlling the behavior of the Clang preprocessor.

.. option:: -C, --comments

Include comments in preprocessed output

.. option:: -CC, --comments-in-macros

Include comments from within macros in preprocessed output

.. option:: -D<macro>=<value>, --define-macro <arg>, --define-macro=<arg>

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

.. option:: -H, --trace-includes

Show header includes and nesting depth

.. option:: -P, --no-line-commands

Disable linemarker output in -E mode

.. option:: -U<macro>, --undefine-macro <arg>, --undefine-macro=<arg>

Undefine macro <macro>

.. option:: -Wp,<arg>,<arg2>...

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

.. option:: -Xpreprocessor <arg>

Pass <arg> to the preprocessor

.. option:: --embed-dir=<dir>

Add directory to embed search path

Include path management
-----------------------

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

.. option:: -I<dir>, --include-directory <arg>, --include-directory=<arg>

Add directory to include search path. For C++ inputs, if
there are multiple -I options, these directories are searched
in the order they are given before the standard system directories
are searched. If the same directory is in the SYSTEM include search
paths, for example if also specified with -isystem, the -I option
will be ignored

.. option:: -cxx-isystem<directory>

Add directory to the C++ SYSTEM include search path

.. option:: -fbuild-session-file=<file>

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

.. option:: -fbuild-session-timestamp=<time since Epoch in seconds>

Time when the current build session started

.. option:: -fmodule-file=\[<name>=\]<file>

Specify the mapping of module name to precompiled module file, or load a module file if name is omitted.

.. option:: -fmodules-cache-path=<directory>

Specify the module cache path

.. option:: -fmodules-disable-diagnostic-validation

Disable validation of the diagnostic options when loading the module

.. option:: -fmodules-force-validate-user-headers, -fno-modules-force-validate-user-headers

Force validation of user headers when repeatedly loading a module file within single build session

.. option:: -fmodules-prune-after=<seconds>

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

.. option:: -fmodules-prune-interval=<seconds>

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

.. option:: -fmodules-user-build-path <directory>

Specify the module user build path

.. option:: -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

.. option:: -fmodules-validate-system-headers, -fno-modules-validate-system-headers

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

.. option:: -fprebuilt-module-path=<directory>

Specify the prebuilt module path

.. option:: -iapinotes-modules<directory>

Add directory to the API notes search path referenced by module name

.. option:: -ibuiltininc

Enable builtin #include directories even when -nostdinc is used before or after -ibuiltininc. Using -nobuiltininc after the option disables it

.. option:: -idirafter<arg>, --include-directory-after <arg>, --include-directory-after=<arg>

Add directory to AFTER include search path

.. option:: -iframework<arg>

Add directory to SYSTEM framework search path

.. option:: -iframeworkwithsysroot<directory>

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

.. option:: -imacros<file>, --imacros<file>, --imacros=<arg>

Include macros from file before parsing

.. option:: -include<file>, --include<file>, --include=<arg>

Include file before parsing

.. option:: -include-pch <file>

Include precompiled header file

.. option:: -iprefix<dir>, --include-prefix <arg>, --include-prefix=<arg>

Set the -iwithprefix/-iwithprefixbefore prefix

.. option:: -iquote<directory>

Add directory to QUOTE include search path

.. option:: -isysroot<dir>

Set the system root directory (usually /)

.. option:: -isystem<directory>

Add directory to SYSTEM include search path

.. option:: -isystem-after<directory>

Add directory to end of the SYSTEM include search path

.. option:: -ivfsoverlay<arg>

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

.. option:: -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

.. option:: -iwithprefixbefore<dir>, --include-with-prefix-before <arg>, --include-with-prefix-before=<arg>

Set directory to include search path with prefix

.. option:: -iwithsysroot<directory>

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

.. option:: --libomptarget-amdgpu-bc-path=<arg>, --libomptarget-amdgcn-bc-path=<arg>

Path to libomptarget-amdgcn bitcode library

.. option:: --libomptarget-nvptx-bc-path=<arg>

Path to libomptarget-nvptx bitcode library

.. option:: --libomptarget-spirv-bc-path=<arg>

Path to libomptarget-spirv bitcode library

.. option:: -nobuiltininc

Disable builtin #include directories only

.. option:: -nohipwrapperinc

Do not include the default HIP wrapper headers and include paths

.. option:: -nostdinc, --no-standard-includes

Disable both standard system #include directories and builtin #include directories

.. program:: clang1
.. option:: -nostdinc++
.. program:: clang

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

.. option:: -nostdlibinc

Disable standard system #include directories only

.. option:: --offload-inc, --no-offload-inc

Add include paths for CUDA/HIP and include the default CUDA/HIP wrapper headers (default)

.. program:: clang1
.. option:: -stdlib++-isystem<directory>
.. program:: clang

Use directory as the C++ standard library include path

.. option:: --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.

.. option:: -M, --dependencies

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

.. option:: -MD, --write-dependencies

Write a depfile containing user and system headers

.. option:: -MF<file>

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

.. option:: -MG, --print-missing-file-dependencies

Add missing headers to depfile

.. option:: -MJ<arg>

Write a compilation database entry per input

.. option:: -MM, --user-dependencies

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

.. option:: -MMD, --write-user-dependencies

Write a depfile containing user headers

.. option:: -MP

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

.. option:: -MQ<arg>

Specify name of main file output to quote in depfile

.. option:: -MT<arg>

Specify name of main file output in depfile

.. option:: -MV

Use NMake/Jom format for the depfile

Dumping preprocessor state
--------------------------

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

.. option:: -d

.. program:: clang1
.. option:: -d<arg>
.. program:: clang

.. option:: -dD

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

.. option:: -dI

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

.. option:: -dM

Print macro definitions in -E mode instead of normal output

Diagnostic options
~~~~~~~~~~~~~~~~~~
Flags controlling which warnings, errors, and remarks Clang will generate. See the :doc:`full list of warning and remark flags <DiagnosticsReference>`.

.. option:: -R<remark>

Enable the specified remark

.. option:: -Rpass-analysis=<arg>

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

.. option:: -Rpass-missed=<arg>

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

.. option:: -Rpass=<arg>

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

.. option:: -W<warning>, --extra-warnings, -fheinous-gnu-extensions (equivalent to -Wno-error=invalid-gnu-asm-cast), --warn-<arg>, --warn-=<arg>

Enable the specified warning

.. option:: -Wframe-larger-than=<arg>, -Wframe-larger-than

.. option:: -Wnonportable-cfstrings<arg>, -Wno-nonportable-cfstrings<arg>

.. option:: --warning-suppression-mappings=<arg>

File containing diagnostic suppression mappings. See user manual for file format.

Target-independent compilation options
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. option:: -clangir-lib-opt=<arg>, -clangir-lib-opt (equivalent to -clangir-lib-opt=all)

Enable C/C++ library based optimizations (with options). <arg> must be 'all'.

.. option:: -fPIC, -fno-PIC

.. option:: -fPIE, -fno-PIE

.. option:: -faarch64-jump-table-hardening, -fno-aarch64-jump-table-hardening

Use hardened lowering for jump-table dispatch

.. option:: -faccess-control, -fno-access-control

.. option:: -faddrsig, -fno-addrsig

Emit an address-significance table

.. option:: -falign-functions, -fno-align-functions

.. program:: clang1
.. option:: -falign-functions=<arg>
.. program:: clang

.. option:: -falign-loops=<N>

N must be a power of two. Align loops to the boundary

.. program:: clang1
.. option:: -faligned-allocation, -faligned-new, -fno-aligned-allocation
.. program:: clang

Enable C++17 aligned allocation functions

.. option:: -falloc-token-max=<N>

Limit to maximum N allocation tokens (0 = target SIZE_MAX)

.. option:: -fallow-editor-placeholders, -fno-allow-editor-placeholders

Treat editor placeholders as valid source code

.. option:: -fallow-unsupported

.. option:: -faltivec, -fno-altivec

.. option:: -faltivec-src-compat=<arg>

Source-level compatibility for Altivec vectors (for PowerPC targets). This includes results of vector comparison (scalar for 'xl', vector for 'gcc') as well as behavior when initializing with a scalar (splatting for 'xl', element zero only for 'gcc'). For 'mixed', the compatibility is as 'gcc' for 'vector bool/vector pixel' and as 'xl' for other types. Current default is 'mixed'. <arg> must be 'mixed', 'gcc' or 'xl'.

.. option:: -fandroid-pad-segment, -fno-android-pad-segment

.. option:: -fansi-escape-codes

Use ANSI escape codes for diagnostics

.. option:: -fapple-kext, -findirect-virtual-calls, -fterminated-vtables

Use Apple's kernel extensions ABI

.. option:: -fapple-link-rtlib

Force linking the clang builtins runtime library

.. option:: -fapple-pragma-pack, -fno-apple-pragma-pack

Enable Apple gcc-compatible #pragma pack handling

.. option:: -fapplication-extension, -fno-application-extension

Restrict code to those available for App Extensions

.. option:: -fapprox-func, -fno-approx-func

Allow certain math function calls to be replaced with an approximately equivalent calculation

.. option:: -fasm, -fno-asm

.. option:: -fasm-blocks, -fno-asm-blocks

.. option:: -fassociative-math, -fno-associative-math

.. option:: -fassume-nothrow-exception-dtor, -fno-assume-nothrow-exception-dtor

Assume that exception objects' destructors are non-throwing

.. option:: -fassume-sane-operator-new, -fno-assume-sane-operator-new

.. option:: -fassume-unique-vtables, -fno-assume-unique-vtables

.. option:: -fassumptions, -fno-assumptions

.. option:: -fast

.. option:: -fastcp

.. option:: -fastf

.. option:: -fasync-exceptions, -fno-async-exceptions

Enable EH Asynchronous exceptions

.. option:: -fasynchronous-unwind-tables, -fno-asynchronous-unwind-tables

.. option:: -fatomic-fine-grained-memory, -fno-atomic-fine-grained-memory

May have atomic operations on fine-grained memory

.. option:: -fatomic-ignore-denormal-mode, -fno-atomic-ignore-denormal-mode, -munsafe-fp-atomics

Allow atomic operations to ignore denormal mode

.. option:: -fatomic-remote-memory, -fno-atomic-remote-memory

May have atomic operations on remote memory

.. option:: -fauto-import, -fno-auto-import

MinGW specific. Enable code generation support for automatic dllimport, and enable support for it in the linker. Enabled by default.

.. option:: -fautolink, -fno-autolink

.. option:: -fbasic-block-address-map, -fno-basic-block-address-map

Emit the basic block address map section.

.. option:: -fbasic-block-sections=<arg>

Place each basic block or a subset of basic blocks in its own section. <arg> must be 'all', 'none' or 'list='.

.. option:: -fbinutils-version=<major.minor>

Produced object files can use all ELF features supported by this binutils version and newer. If -fno-integrated-as is specified, the generated assembly will consider GNU as support. 'none' means that all ELF features can be used, regardless of binutils support. Defaults to 2.26.

.. option:: -fblocks, -fno-blocks

Enable the 'blocks' language feature

.. option:: -fbootclasspath=<arg>, --bootclasspath <arg>, --bootclasspath=<arg>

.. option:: -fborland-extensions, -fno-borland-extensions

Accept non-standard constructs supported by the Borland compiler

.. option:: -fbracket-depth=<arg>

.. option:: -fbuiltin, -fno-builtin

.. option:: -fbuiltin-module-map

Load the clang builtins module map file.

.. program:: clang1
.. option:: -fc++-static-destructors=<arg>, -fc++-static-destructors (equivalent to -fc++-static-destructors=all), -fno-c++-static-destructors (equivalent to -fc++-static-destructors=none)
.. program:: clang

Controls which variables C++ static destructors are registered for. <arg> must be 'all', 'thread-local' or 'none'.

.. option:: -fcaret-diagnostics, -fno-caret-diagnostics

.. option:: -fcaret-diagnostics-max-lines=<arg>

Set the maximum number of source lines to show in a caret diagnostic (0 = no limit).

.. option:: -fcf-protection=<arg>, -fcf-protection (equivalent to -fcf-protection=full)

Instrument control-flow architecture protection. <arg> must be 'return', 'branch', 'full' or 'none'.

.. option:: -fcf-runtime-abi=<arg>

 <arg> must be 'unspecified', 'standalone', 'objc', 'swift', 'swift-5.0', 'swift-4.2' or 'swift-4.1'.

.. option:: -fchar8_t, -fno-char8_t

Enable C++ builtin type char8_t

.. option:: -fclangir, -fno-clangir

Use the ClangIR pipeline to compile

.. option:: -fclasspath=<arg>, --CLASSPATH <arg>, --CLASSPATH=<arg>, --classpath <arg>, --classpath=<arg>

.. option:: -fcodegen-data-generate=<path>, -fcodegen-data-generate (equivalent to -fcodegen-data-generate=default.cgdata)

Emit codegen data into the object file. LLD for MachO (currently) merges them into the specified <path>.

.. option:: -fcodegen-data-use=<path>, -fcodegen-data-use (equivalent to -fcodegen-data-use=default.cgdata)

Use codegen data read from the specified <path>.

.. option:: -fcolor-diagnostics, -fdiagnostics-color, -fno-color-diagnostics

Enable colors in diagnostics

.. option:: -fcommon, -fno-common

Place definitions of variables with no storage class and no initializer
(tentative definitions) in a common block, instead of generating individual
zero-initialized definitions (default -fno-common).

.. option:: -fcompile-resource=<arg>, --resource <arg>, --resource=<arg>

.. option:: -fcomplex-arithmetic=<arg>

Controls the calculation methods of complex number multiplication and division. <arg> must be 'full', 'improved', 'promoted' or 'basic'.

.. option:: -fconstant-array-class=<arg>

.. option:: -fconstant-cfstrings, -fno-constant-cfstrings

.. option:: -fconstant-dictionary-class=<arg>

.. option:: -fconstant-double-number-class=<arg>

.. option:: -fconstant-float-number-class=<arg>

.. option:: -fconstant-integer-number-class=<arg>

.. option:: -fconstant-nsarray-literals, -fno-constant-nsarray-literals

Enable compile-time constant NSArray literals

.. option:: -fconstant-nsdictionary-literals, -fno-constant-nsdictionary-literals

Enable compile-time constant NSDictionary literals

.. option:: -fconstant-nsnumber-literals, -fno-constant-nsnumber-literals

Enable compile-time constant NSNumber literals

.. option:: -fconstant-string-class=<arg>

.. option:: -fconstexpr-backtrace-limit=<arg>

Set the maximum number of entries to print in a constexpr evaluation backtrace (0 = no limit)

.. option:: -fconstexpr-depth=<arg>

Set the maximum depth of recursive constexpr function calls

.. option:: -fconstexpr-steps=<arg>

Set the maximum number of steps in constexpr function evaluation (0 = no limit)

.. option:: -fcoro-aligned-allocation, -fno-coro-aligned-allocation

Prefer aligned allocation for C++ Coroutines

.. option:: -fcoroutines, -fno-coroutines

Enable support for the C++ Coroutines

.. option:: -fcoverage-compilation-dir=<arg>

The compilation directory to embed in the coverage mapping.

.. option:: -fcoverage-mapping, -fno-coverage-mapping

Generate coverage mapping to enable code coverage analysis

.. option:: -fcoverage-mcdc, -fno-coverage-mcdc

Enable MC/DC criteria when generating code coverage

.. option:: -fcoverage-prefix-map=<old>=<new>

remap file source paths <old> to <new> in coverage mapping. If there are multiple options, prefix replacement is applied in reverse order starting from the last one

.. option:: -fcreate-profile

.. option:: -fcs-profile-generate

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

.. program:: clang1
.. option:: -fcs-profile-generate=<directory>
.. program:: clang

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

.. option:: -fcxx-exceptions, -fno-cxx-exceptions

Enable C++ exceptions

.. option:: -fcxx-modules, -fno-cxx-modules

Enable modules for C++

.. option:: -fdata-sections, -fno-data-sections

Place each data in its own section

.. option:: -fdebug-compilation-dir=<arg>, -fdebug-compilation-dir <arg>

The compilation directory to embed in the debug info

.. option:: -fdebug-default-version=<arg>

Default DWARF version to use, if a -g option caused DWARF debug info to be produced

.. option:: -fdebug-info-for-profiling, -fno-debug-info-for-profiling

Emit extra debug info to make sample profile more accurate

.. option:: -fdebug-macro, -fno-debug-macro

Emit macro debug information

.. option:: -fdebug-pass-arguments

.. option:: -fdebug-pass-structure

.. option:: -fdebug-prefix-map=<old>=<new>

For paths in debug info, remap directory <old> to <new>. If multiple options match a path, the last option wins

.. option:: -fdebug-ranges-base-address, -fno-debug-ranges-base-address

Use DWARF base address selection entries in .debug_ranges

.. option:: -fdebug-record-sysroot, -fno-debug-record-sysroot

Record the sysroot path in debug info as DW_AT_LLVM_sysroot and in DW_AT_LLVM_include_path (used by LLDB to locate the SDK for Clang module imports).

.. option:: -fdebug-types-section, -fno-debug-types-section

Place debug types in their own section (ELF Only)

.. option:: -fdefer-ts, -fno-defer-ts

Enable support for the C '_Defer' Technical Specification

.. option:: -fdefine-target-os-macros, -fno-define-target-os-macros

Enable predefined target OS macros

.. option:: -fdelayed-template-parsing, -fno-delayed-template-parsing

Parse templated function definitions at the end of the translation unit

.. option:: -fdelete-null-pointer-checks, -fno-delete-null-pointer-checks

When enabled, treat null pointer dereference, creation of a reference to null,
or passing a null pointer to a function parameter annotated with the "nonnull"
attribute as undefined behavior. (And, thus the optimizer may assume that any
pointer used in such a way must not have been null and optimize away the
branches accordingly.) On by default.

.. option:: -fdenormal-fp-math=<arg>

.. option:: -fdevirtualize-speculatively, -fno-devirtualize-speculatively

Enables speculative devirtualization optimization.

.. option:: -fdiagnostics-absolute-paths

Print absolute paths in diagnostics

.. program:: clang1
.. option:: -fdiagnostics-color=<arg>
.. program:: clang

When to use colors in diagnostics. <arg> must be 'auto', 'always' or 'never'.

.. option:: -fdiagnostics-hotness-threshold=<value>

Prevent optimization remarks from being output if they do not have at least this profile count. Use 'auto' to apply the threshold from profile summary

.. option:: -fdiagnostics-misexpect-tolerance=<value>

Prevent misexpect diagnostics from being output if the profile counts are within N% of the expected. 

.. option:: -fdiagnostics-show-hotness, -fno-diagnostics-show-hotness

Enable profile hotness information in diagnostic line

.. option:: -fdiagnostics-show-inlining-chain, -fno-diagnostics-show-inlining-chain

Show inlining chain notes for \[\[gnu::warning/error\]\] diagnostics

.. option:: -fdiagnostics-show-line-numbers, -fno-diagnostics-show-line-numbers

.. option:: -fdiagnostics-show-note-include-stack, -fno-diagnostics-show-note-include-stack

Display include stacks for diagnostic notes

.. option:: -fdiagnostics-show-option, -fno-diagnostics-show-option

Print option name with mappable diagnostics

.. option:: -fdiagnostics-show-template-tree

Print a template comparison tree for differing templates

.. option:: -fdigraphs, -fno-digraphs

Enable alternative token representations '<:', ':>', '<%', '%>', '%:', '%:%:' (default)

.. option:: -fdirect-access-external-data, -fno-direct-access-external-data

Don't use GOT indirection to reference external data symbols

.. option:: -fdirectives-only, -fno-directives-only

.. option:: -fdisable-block-signature-string, -fno-disable-block-signature-string

Disable block signature string)

.. option:: -fdollars-in-identifiers, -fno-dollars-in-identifiers

Allow '$' in identifiers

.. option:: -fdouble-square-bracket-attributes, -fno-double-square-bracket-attributes

.. option:: -fdwarf-directory-asm, -fno-dwarf-directory-asm

.. option:: -fdwarf-exceptions

Use DWARF style exceptions

.. option:: -fdwarf2-cfi-asm, -fno-dwarf2-cfi-asm

.. option:: -felide-constructors, -fno-elide-constructors

.. option:: -feliminate-unused-debug-symbols, -fno-eliminate-unused-debug-symbols

.. option:: -feliminate-unused-debug-types, -fno-eliminate-unused-debug-types

Do not emit  debug info for defined but unused types

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

Embed LLVM bitcode. <option> must be 'off', 'all', 'bitcode' or 'marker'.

.. option:: -fembed-offload-object=<arg>

Embed Offloading device-side binary into host object file as a section.

.. option:: -femit-all-decls

Emit all declarations, even if unused

.. option:: -femit-compact-unwind-non-canonical, -fno-emit-compact-unwind-non-canonical

Try emitting Compact-Unwind for non-canonical entries. Maybe overridden by other constraints

.. option:: -femit-dwarf-unwind=<arg>

When to emit DWARF unwind (EH frame) info. <arg> must be 'always', 'no-compact-unwind', 'dwarf-only' or 'default'.

.. option:: -femulated-tls, -fno-emulated-tls

Use emutls functions to access thread_local variables

.. option:: -fenable-matrix

Enable matrix data type and related builtin functions

.. option:: -fenable-new-pm-codegen, -fno-enable-new-pm-codegen

When enabled, use the NewPM to drive the Codegen pipeline.

.. option:: -fencoding=<arg>, --encoding <arg>, --encoding=<arg>

.. option:: -ferror-limit=<arg>

.. option:: -fescaping-block-tail-calls, -fno-escaping-block-tail-calls

.. option:: -fexceptions, -fno-exceptions

Enable support for exception handling

.. option:: -fexcess-precision=<arg>

Allows control over excess precision on targets where native support for the precision types is not available. By default, excess precision is used to calculate intermediate results following the rules specified in ISO C99. <arg> must be 'standard', 'fast' or 'none'.

.. option:: -fexec-charset=<arg>

.. option:: -fexperimental-allow-pointer-field-protection-attr, -fno-experimental-allow-pointer-field-protection-attr

Allow the use of the \[\[clang::pointer_field_protection\]\] attribute

.. option:: -fexperimental-call-graph-section, -fno-experimental-call-graph-section

Emit a call graph section

.. option:: -fexperimental-late-parse-attributes, -fno-experimental-late-parse-attributes

Enable experimental late parsing of attributes

.. option:: -fexperimental-library, -fno-experimental-library

Control whether unstable and experimental library features are enabled. This option enables various library features that are either experimental (also known as TSes), or have been but are not stable yet in the selected Standard Library implementation. It is not recommended to use this option in production code, since neither ABI nor API stability are guaranteed. This is intended to provide a preview of features that will ship in the future for experimentation purposes

.. option:: -fexperimental-loop-fusion, -fno-experimental-loop-fusion

EnableEnable the loop fusion pass

.. option:: -fexperimental-new-constant-interpreter, -fno-experimental-new-constant-interpreter

.. option:: -fexperimental-openacc-macro-override <arg>, -fexperimental-openacc-macro-override=<arg>

Overrides the _OPENACC macro value for experimental testing during OpenACC support development

.. option:: -fexperimental-pointer-field-protection-abi, -fno-experimental-pointer-field-protection-abi

Enable pointer field protection on all non-standard layout struct types

.. option:: -fexperimental-pointer-field-protection-tagged, -fno-experimental-pointer-field-protection-tagged

Use pointer identity (tag) to discriminate pointers of non-trivially-copyable types

.. option:: -fexperimental-sanitize-metadata-ignorelist=<arg>

Disable sanitizer metadata for modules and functions that match the provided special case list

.. option:: -fexperimental-sanitize-metadata=<arg1>,<arg2>..., -fno-experimental-sanitize-metadata=<arg1>,<arg2>...

Specify the type of metadata to emit for binary analysis sanitizers

.. option:: -fextdirs=<arg>, --extdirs <arg>, --extdirs=<arg>

.. option:: -fextend-arguments=<arg>

Controls how scalar integer arguments are extended in calls to unprototyped and varargs functions. <arg> must be '32' or '64'.

.. option:: -fextend-variable-liveness=<arg>, -fextend-variable-liveness (equivalent to -fextend-variable-liveness=all)

Extend the liveness of user variables through optimizations to prevent stale or optimized-out variable values when debugging. <arg> must be 'all', 'this' or 'none'.

.. option:: -ffast-math, -fno-fast-math

Allow aggressive, lossy floating-point optimizations

.. option:: -ffat-lto-objects, -fno-fat-lto-objects

Enable fat LTO object support

.. option:: -ffile-compilation-dir=<arg>

The compilation directory to embed in the debug info and coverage mapping.

.. option:: -ffile-prefix-map=<arg>

remap file source paths in debug info, coverage mapping, predefined preprocessor macros and __builtin_FILE(). Implies -ffile-reproducible.

.. option:: -ffile-reproducible, -fno-file-reproducible

Use the target's platform-specific path separator character when expanding the __FILE__ macro

.. option:: -ffinite-loops, -fno-finite-loops

Assume all non-trivial loops are finite.

.. option:: -ffixed-point, -fno-fixed-point

Enable fixed point types

.. option:: -ffor-scope, -fno-for-scope

.. option:: -fforce-check-cxx20-modules-input-files

Check the input source files from C++20 modules explicitly

.. option:: -fforce-dwarf-frame, -fno-force-dwarf-frame

Always emit a debug frame section

.. option:: -fforce-emit-vtables, -fno-force-emit-vtables

In order to improve devirtualization, forces emitting of vtables even in
modules where it isn't necessary. It causes more inline virtual functions
to be emitted.

.. option:: -fforce-enable-int128, -fno-force-enable-int128

Enable support for int128_t type

.. option:: -ffp-contract=<arg>

Form fused FP ops (e.g. FMAs): fast (fuses across statements disregarding pragmas) | on (only fuses in the same statement unless dictated by pragmas) | off (never fuses) | fast-honor-pragmas (fuses across statements unless dictated by pragmas). Default is 'fast' for CUDA, 'fast-honor-pragmas' for HIP, and 'on' otherwise. <arg> must be 'fast', 'on', 'off' or 'fast-honor-pragmas'.

.. option:: -ffp-eval-method=<arg>

Specifies the evaluation method to use for floating-point arithmetic. <arg> must be 'source', 'double' or 'extended'.

.. option:: -ffp-exception-behavior=<arg>

Specifies the exception behavior of floating-point operations. <arg> must be 'ignore', 'maytrap' or 'strict'.

.. option:: -ffp-model=<arg>

Controls the semantics of floating-point calculations.

.. option:: -ffreestanding

Assert that the compilation takes place in a freestanding environment

.. option:: -ffunction-sections, -fno-function-sections

Place each function in its own section

.. option:: -fgnu-inline-asm, -fno-gnu-inline-asm

.. option:: -fgnu-keywords, -fno-gnu-keywords

Allow GNU-extension keywords regardless of language standard

.. option:: -fgnu-runtime

Generate output compatible with the standard GNU Objective-C runtime

.. option:: -fgnu89-inline, -fno-gnu89-inline

Use the gnu89 inline semantics

.. option:: -fgnuc-version=<arg>

Sets various macros to claim compatibility with the given GCC version (default is 4.2.1)

.. option:: -fgpu-approx-transcendentals, -fcuda-approx-transcendentals, -fno-gpu-approx-transcendentals

Use approximate transcendental functions

.. option:: -fhonor-infinities, -fhonor-infinites, -fno-honor-infinities

Specify that floating-point optimizations are not allowed that assume arguments and results are not +-inf.

.. option:: -fhonor-nans, -fno-honor-nans

Specify that floating-point optimizations are not allowed that assume arguments and results are not NANs.

.. option:: -fhosted

.. option:: -fignore-exceptions

Enable support for ignoring exception handling constructs

.. option:: -fimplicit-module-maps, -fmodule-maps, -fno-implicit-module-maps

Implicitly search the file system for module map files.

.. option:: -fimplicit-modules, -fno-implicit-modules

.. option:: -fincremental-extensions

Enable incremental processing extensions such as processing statements on the global scope.

.. option:: -finline-max-stacksize=<arg>

Suppress inlining of functions whose stack size exceeds the given value

.. option:: -finput-charset=<arg>

Specify the default character set for source files

.. option:: -finstrument-function-entry-bare

Instrument function entry only, after inlining, without arguments to the instrumentation call

.. option:: -finstrument-functions

Generate calls to instrument function entry and exit

.. option:: -finstrument-functions-after-inlining

Like -finstrument-functions, but insert the calls after inlining

.. option:: -fintegrated-as, -fno-integrated-as, -integrated-as

Enable the integrated assembler

.. option:: -fintegrated-cc1, -fno-integrated-cc1

Run cc1 in-process

.. option:: -fintegrated-objemitter, -fno-integrated-objemitter

Use internal machine object code emitter.

.. option:: -fjmc, -fno-jmc

Enable just-my-code debugging

.. option:: -fjump-tables, -fno-jump-tables

Use jump tables for lowering switches

.. option:: -fkeep-persistent-storage-variables, -fno-keep-persistent-storage-variables

Enable keeping all variables that have a persistent storage duration, including global, static and thread-local variables, to guarantee that they can be directly addressed

.. option:: -fkeep-static-consts, -fno-keep-static-consts

Keep static const variables even if unused

.. option:: -fkeep-system-includes, -fno-keep-system-includes

Instead of expanding system headers when emitting preprocessor output, preserve the #include directive. Useful when producing preprocessed output for test case reduction. May produce incorrect output if preprocessor symbols that control the included content (e.g. _XOPEN_SOURCE) are defined in the including source file. The portability of the resulting source to other compilation environments is not guaranteed.

Only valid with -E.

.. option:: -flax-vector-conversions=<arg>, -flax-vector-conversions (equivalent to -flax-vector-conversions=integer), -fno-lax-vector-conversions (equivalent to -flax-vector-conversions=none)

Enable implicit vector bit-casts. <arg> must be 'none', 'integer' or 'all'.

.. option:: -flifetime-dse, -fno-lifetime-dse

When enabled, mark an object dead after its destructor returns which allows the
the optimizer to perform more aggressive optimizations in some cases, particularly dead
store elimination.

.. option:: -flimited-precision=<arg>

.. option:: -floop-interchange, -fno-loop-interchange

Enable the loop interchange pass

.. option:: -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)

.. option:: -flto-partitions=<arg>

Number of partitions to use for parallel full LTO codegen, ld.lld only.

.. option:: -flto=<arg>, -flto (equivalent to -flto=full), -flto=auto (equivalent to -flto=full), -flto=jobserver (equivalent to -flto=full)

Set LTO mode. <arg> must be 'thin' or 'full'.

.. option:: -fmacro-backtrace-limit=<arg>

Set the maximum number of entries to print in a macro expansion backtrace (0 = no limit)

.. option:: -fmacro-prefix-map=<arg>

remap file source paths in predefined preprocessor macros and __builtin_FILE(). Implies -ffile-reproducible.

.. option:: -fmath-errno, -fno-math-errno

Require math functions to indicate errors by setting errno

.. option:: -fmatrix-memory-layout=<arg>

Sets the matrix memory layout (row-major or column-major). <arg> must be 'row-major' or 'column-major'.

.. option:: -fmax-tokens=<arg>

Max total number of preprocessed tokens for -Wmax-tokens.

.. option:: -fmax-type-align=<arg>

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

.. option:: -fmemory-profile, -fno-memory-profile

Enable heap memory profiling

.. option:: -fmemory-profile-use=<pathname>

Use memory profile for profile-guided memory optimization

.. program:: clang1
.. option:: -fmemory-profile=<directory>
.. program:: clang

Enable heap memory profiling and dump results into <directory>

.. option:: -fmerge-all-constants, -fno-merge-all-constants

Allow merging of constants

.. option:: -fmessage-length=<arg>

Format message diagnostics so that they fit within N columns

.. option:: -fminimize-whitespace, -fno-minimize-whitespace

Ignore the whitespace from the input file when emitting preprocessor output. It will only contain whitespace when necessary, e.g. to keep two minus signs from merging into to an increment operator. Useful with the -P option to normalize whitespace such that two files with only formatting changes are equal.

Only valid with -E on C-like inputs and incompatible with -traditional-cpp.

.. option:: -fmodule-file-deps, -fno-module-file-deps

.. program:: clang1
.. option:: -fmodule-file-deps=<arg>
.. program:: clang

Include module files in dependency output. <arg> must be 'none', 'all' or 'direct'.

.. option:: -fmodule-header

Build a C++20 Header Unit from a header

.. program:: clang1
.. option:: -fmodule-header=<kind>
.. program:: clang

Build a C++20 Header Unit from a header that should be found in the user (fmodule-header=user) or system (fmodule-header=system) search path.

.. option:: -fmodule-map-file=<file>

Load this module map file

.. option:: -fmodule-name=<name>, -fmodule-implementation-of <arg>

Specify the name of the module to build

.. option:: -fmodulemap-allow-subdirectory-search, -fno-modulemap-allow-subdirectory-search

Allow to search for module maps in subdirectories of search paths

.. option:: -fmodules, -fno-modules

Enable the 'modules' language feature

.. option:: -fmodules-decluse, -fno-modules-decluse

Require declaration of modules used within a module

.. option:: -fmodules-driver, -fno-modules-driver

Enable support for driver managed module builds (experimental)

.. option:: -fmodules-ignore-macro=<arg>

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

.. option:: -fmodules-search-all, -fno-modules-search-all

Search even non-imported modules to resolve references

.. option:: -fmodules-strict-decluse

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

.. option:: -fmodules-validate-input-files-content

Validate PCM input files based on content if mtime differs

.. option:: -fms-anonymous-structs, -fno-ms-anonymous-structs

Enable Microsoft anonymous struct/union extension.

.. option:: -fms-compatibility, -fno-ms-compatibility

Enable full Microsoft Visual C++ compatibility

.. option:: -fms-compatibility-version=<arg>

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

.. option:: -fms-define-stdc

Define '__STDC__' to '1' in MSVC Compatibility mode

.. option:: -fms-extensions, -fno-ms-extensions

Accept some non-standard constructs supported by the Microsoft compiler

.. option:: -fms-hotpatch

Ensure that all functions can be hotpatched at runtime

.. option:: -fms-memptr-rep=<arg>

 <arg> must be 'single', 'multiple' or 'virtual'.

.. option:: -fms-omit-default-lib<arg>

.. option:: -fms-runtime-lib=<arg>


Specify Visual Studio C runtime library. "static" and "static_dbg" correspond
to the cl flags /MT and /MTd which use the multithread, static version. "dll"
and "dll_dbg" correspond to the cl flags /MD and /MDd which use the multithread,
dll version. <arg> must be 'static', 'static_dbg', 'dll' or 'dll_dbg'.

.. option:: -fms-secure-hotpatch-functions-file=<arg>

Path to a file that contains a list of mangled names of functions that should be hot-patched for Windows Secure Hot-Patching

.. option:: -fms-secure-hotpatch-functions-list=<arg1>,<arg2>...

List of mangled symbol names of functions that should be hot-patched for Windows Secure Hot-Patching

.. option:: -fms-tls-guards, -fno-ms-tls-guards

.. option:: -fms-volatile, -fno-ms-volatile

Volatile loads and stores have acquire and release semantics

.. option:: -fmsc-version=<arg>

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

.. option:: -fmudflap

.. option:: -fmudflapth

.. option:: -fnamed-loops, -fno-named-loops

Enable support for named loops

.. option:: -fnested-functions

.. option:: -fnew-alignment=<align>, -fnew-alignment <arg>

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

.. option:: -fnew-infallible, -fno-new-infallible

Enable treating throwing global C++ operator new as always returning valid memory (annotates with __attribute__((returns_nonnull)) and throw()). This is detectable in source.

.. option:: -fnext-runtime

.. option:: -fno-builtin-<arg>

Disable implicit builtin knowledge of a specific function

.. option:: -fno-elide-type

Do not elide types when printing diagnostics

.. option:: -fno-knr-functions

Disable support for K&R C function declarations

.. option:: -fno-max-type-align

.. option:: -fno-modules-validate-textual-header-includes

Do not enforce -fmodules-decluse and private header restrictions for textual headers. This flag will be removed in a future Clang release.

.. option:: -fno-profile-sample-use, -fno-auto-profile

.. option:: -fno-strict-bool=<arg>

Disable optimizations based on bool bit patterns never being anything other than 0 or 1, specifying a conversion behavior. <arg> must be 'truncate' or 'nonzero'.

.. option:: -fno-strict-modules-decluse

.. option:: -fno-temp-file

Directly create compilation output files. This may lead to incorrect incremental builds if the compiler crashes

.. option:: -fno-working-directory

.. option:: -fno_modules-validate-input-files-content

.. program:: clang1
.. option:: -fno_pch-validate-input-files-content
.. program:: clang

.. option:: -fobjc-abi-version=<arg>

.. option:: -fobjc-arc, -fno-objc-arc

Synthesize retain and release calls for Objective-C pointers

.. option:: -fobjc-arc-exceptions, -fno-objc-arc-exceptions

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

.. option:: -fobjc-avoid-heapify-local-blocks, -fno-objc-avoid-heapify-local-blocks

Try to avoid heapifying local blocks

.. option:: -fobjc-constant-literals, -fno-objc-constant-literals

Enable compile-time constant ObjC literals

.. option:: -fobjc-convert-messages-to-runtime-calls, -fno-objc-convert-messages-to-runtime-calls

.. option:: -fobjc-direct-precondition-thunk, -fno-objc-direct-precondition-thunk

Move precondition checks for direct methods into thunks

.. option:: -fobjc-disable-direct-methods-for-testing

Ignore attribute objc_direct so that direct methods can be tested

.. option:: -fobjc-encode-cxx-class-template-spec, -fno-objc-encode-cxx-class-template-spec

Fully encode c++ class template specialization

.. option:: -fobjc-exceptions, -fno-objc-exceptions

Enable Objective-C exceptions

.. option:: -fobjc-infer-related-result-type, -fno-objc-infer-related-result-type

.. option:: -fobjc-legacy-dispatch, -fno-objc-legacy-dispatch

.. option:: -fobjc-link-runtime

.. option:: -fobjc-msgsend-class-selector-stubs, -fno-objc-msgsend-class-selector-stubs

.. option:: -fobjc-msgsend-selector-stubs, -fno-objc-msgsend-selector-stubs

.. option:: -fobjc-nonfragile-abi, -fno-objc-nonfragile-abi

.. option:: -fobjc-nonfragile-abi-version=<arg>

.. option:: -fobjc-runtime=<arg>

Specify the target Objective-C runtime kind and version

.. option:: -fobjc-sender-dependent-dispatch

.. option:: -fobjc-weak, -fno-objc-weak

Enable ARC-style weak references in Objective-C

.. option:: -foffload-lto=<arg>, -foffload-lto (equivalent to -foffload-lto=full)

Set LTO mode for offload compilation. <arg> must be 'thin' or 'full'.

.. option:: -foffload-uniform-block, -cl-uniform-work-group-size, -fno-offload-uniform-block

Assume that kernels are launched with uniform block sizes (default true for CUDA/HIP and false otherwise)

.. option:: -fomit-frame-pointer, -fno-omit-frame-pointer

Omit the frame pointer from functions that don't need it. Some stack unwinding cases, such as profilers and sanitizers, may prefer specifying -fno-omit-frame-pointer. On many targets, -O1 and higher omit the frame pointer by default. -m\[no-\]omit-leaf-frame-pointer takes precedence for leaf functions

.. option:: -fopenacc

Enable OpenACC

.. option:: -fopenmp, -fno-openmp

Parse OpenMP pragmas and generate parallel code.

.. option:: -fopenmp-extensions, -fno-openmp-extensions

Enable all Clang extensions for OpenMP directives and clauses

.. option:: -fopenmp-force-usm

Force behavior as if the user specified pragma omp requires unified_shared_memory.

.. option:: -fopenmp-offload-mandatory

Do not create a host fallback if offloading to the device fails.

.. option:: -fopenmp-simd, -fno-openmp-simd

Emit OpenMP code only for SIMD-based constructs.

.. option:: -fopenmp-target-debug, -fno-openmp-target-debug

Enable debugging in the OpenMP offloading device RTL

.. option:: -fopenmp-target-jit

Emit code that can be JIT compiled for OpenMP offloading. Implies -foffload-lto=full

.. option:: -fopenmp-version=<arg>

Set OpenMP version (e.g. 45 for OpenMP 4.5, 51 for OpenMP 5.1). Default value is 51 for Clang

.. program:: clang1
.. option:: -fopenmp=<arg>
.. program:: clang

.. option:: -foperator-arrow-depth=<arg>

Maximum number of 'operator->'s to call for a member access

.. option:: -foperator-names, -fno-operator-names

.. option:: -foptimization-record-file=<file>

Specify the output name of the file containing the optimization remarks. Implies -fsave-optimization-record. On Darwin platforms, this cannot be used with multiple -arch <arch> options.

.. option:: -foptimization-record-passes=<regex>

Only include passes which match a specified regular expression in the generated optimization record (by default, include all passes)

.. option:: -foptimize-sibling-calls, -fno-optimize-sibling-calls

.. option:: -foutput-class-dir=<arg>, --output-class-directory <arg>, --output-class-directory=<arg>

.. option:: -fpack-struct, -fno-pack-struct

.. program:: clang1
.. option:: -fpack-struct=<arg>
.. program:: clang

Specify the default maximum struct packing alignment

.. option:: -fpartition-static-data-sections, -fno-partition-static-data-sections

Enable partition static data sections using PGO profile information and MemProf (x86 and aarch64 ELF). See LLVM MemProf doc for usage.

.. option:: -fpascal-strings, -fno-pascal-strings, -mpascal-strings

Recognize and construct Pascal-style string literals

.. option:: -fpass-plugin=<dsopath>

Load pass plugin from a dynamic shared object file (only with new pass manager).

.. option:: -fpatchable-function-entry=<N,M,Section>

Generate M NOPs before function entry and N-M NOPs after function entry. If section is specified, use it instead of __patchable_function_entries.

.. option:: -fpcc-struct-return

Override the default ABI to return all structs on the stack

.. option:: -fpch-codegen, -fno-pch-codegen

Generate code for uses of this PCH that assumes an explicit object file will be built for the PCH

.. option:: -fpch-debuginfo, -fno-pch-debuginfo

Generate debug info for types in an object file built from this PCH and do not generate them elsewhere

.. option:: -fpch-instantiate-templates, -fno-pch-instantiate-templates

Instantiate templates already while building a PCH

.. option:: -fpch-preprocess

.. option:: -fpch-validate-input-files-content

Validate PCH input files based on content if mtime differs

.. option:: -fpic, -fno-pic

.. option:: -fpie, -fno-pie

.. option:: -fplt, -fno-plt

.. option:: -fplugin=<dsopath>

Load the named plugin (dynamic shared object)

.. option:: -fpointer-tbaa, -fno-pointer-tbaa

.. option:: -fprebuilt-implicit-modules, -fno-prebuilt-implicit-modules

Look up implicit modules in the prebuilt module path

.. option:: -fpreferred-function-alignment=<arg>

preferred alignment for functions

.. option:: -fpreserve-as-comments, -fno-preserve-as-comments

.. option:: -fproc-stat-report<arg>

Print subprocess statistics

.. program:: clang1
.. option:: -fproc-stat-report=<arg>
.. program:: clang

Save subprocess statistics to the given file

.. option:: -fprofile-arcs, -fno-profile-arcs

Instrument code to produce gcov data files (\*.gcda)

.. option:: -fprofile-continuous

Enable continuous instrumentation profiling mode

.. option:: -fprofile-dir=<arg>

.. option:: -fprofile-exclude-files=<arg>

Instrument only functions from files where names don't match all the regexes separated by a semi-colon

.. option:: -fprofile-filter-files=<arg>

Instrument only functions from files where names match any regex separated by a semi-colon

.. option:: -fprofile-function-groups=<N>

Partition functions into N groups and select only functions in group i to be instrumented using -fprofile-selected-function-group

.. option:: -fprofile-generate, -fno-profile-generate

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

.. option:: -fprofile-generate-cold-function-coverage

Generate instrumented code to collect coverage info for cold functions into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var)

.. program:: clang1
.. option:: -fprofile-generate-cold-function-coverage=<directory>
.. program:: clang

Generate instrumented code to collect coverage info for cold functions into <directory>/default.profraw (overridden by LLVM_PROFILE_FILE env var)

.. program:: clang1
.. option:: -fprofile-generate=<directory>
.. program:: clang

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

.. option:: -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)

.. program:: clang1
.. option:: -fprofile-instr-generate=<file>
.. program:: clang

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

.. option:: -fprofile-instr-use, -fno-profile-instr-use, -fprofile-use

.. program:: clang1
.. option:: -fprofile-instr-use=<arg>
.. program:: clang

Use instrumentation data for profile-guided optimization

.. option:: -fprofile-list=<arg>

Filename defining the list of functions/files to instrument. The file uses the sanitizer special case list format.

.. option:: -fprofile-remapping-file=<file>

Use the remappings described in <file> to match the profile data against names in the program

.. option:: -fprofile-sample-accurate, -fauto-profile-accurate, -fno-profile-sample-accurate

Specifies that the sample profile is accurate. If the sample
               profile is accurate, callsites without profile samples are marked
               as cold. Otherwise, treat callsites without profile samples as if
               we have no profile

.. option:: -fprofile-sample-use=<arg>, -fauto-profile=<arg>

Enable sample-based profile guided optimizations

.. option:: -fprofile-selected-function-group=<i>

Partition functions into N groups using -fprofile-function-groups and select only functions in group i to be instrumented. The valid range is 0 to N-1 inclusive

.. option:: -fprofile-update=<method>

Set update method of profile counters. <method> must be 'atomic', 'prefer-atomic' or 'single'.

.. program:: clang1
.. option:: -fprofile-use=<pathname>
.. program:: clang

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

.. option:: -fprotect-parens, -fno-protect-parens

Determines whether the optimizer honors parentheses when floating-point expressions are evaluated

.. option:: -fpseudo-probe-for-profiling, -fno-pseudo-probe-for-profiling

Emit pseudo probes for sample profiling

.. option:: -fptrauth-auth-traps, -fno-ptrauth-auth-traps

Enable traps on authentication failures

.. option:: -fptrauth-block-descriptor-pointers, -fno-ptrauth-block-descriptor-pointers

Enable signing and authentication of block descriptors

.. option:: -fptrauth-calls, -fno-ptrauth-calls

Enable signing and authentication of all indirect calls

.. option:: -fptrauth-elf-got, -fno-ptrauth-elf-got

Enable authentication of pointers from GOT (ELF only)

.. option:: -fptrauth-function-pointer-type-discrimination, -fno-ptrauth-function-pointer-type-discrimination

Enable type discrimination on C function pointers

.. option:: -fptrauth-indirect-gotos, -fno-ptrauth-indirect-gotos

Enable signing and authentication of indirect goto targets

.. option:: -fptrauth-init-fini, -fno-ptrauth-init-fini

Enable signing of function pointers in init/fini arrays

.. option:: -fptrauth-init-fini-address-discrimination, -fno-ptrauth-init-fini-address-discrimination

Enable address discrimination of function pointers in init/fini arrays

.. option:: -fptrauth-intrinsics, -fno-ptrauth-intrinsics

Enable pointer authentication intrinsics

.. option:: -fptrauth-objc-class-ro, -fno-ptrauth-objc-class-ro

Enable signing and authentication for ObjC class_ro pointers

.. option:: -fptrauth-objc-interface-sel, -fno-ptrauth-objc-interface-sel

Enable signing and authentication of Objective-C object's 'SEL' fields

.. option:: -fptrauth-objc-isa, -fno-ptrauth-objc-isa

Enable signing and authentication of Objective-C object's 'isa' field

.. option:: -fptrauth-returns, -fno-ptrauth-returns

Enable signing and authentication of return addresses

.. option:: -fptrauth-type-info-vtable-pointer-discrimination, -fno-ptrauth-type-info-vtable-pointer-discrimination

Enable type and address discrimination of vtable pointer of std::type_info

.. option:: -fptrauth-vtable-pointer-address-discrimination, -fno-ptrauth-vtable-pointer-address-discrimination

Enable address discrimination of vtable pointers

.. option:: -fptrauth-vtable-pointer-type-discrimination, -fno-ptrauth-vtable-pointer-type-discrimination

Enable type discrimination of vtable pointers

.. option:: -fraw-string-literals, -fno-raw-string-literals

Enable raw string literals

.. option:: -freciprocal-math, -fno-reciprocal-math

Allow division operations to be reassociated

.. option:: -frecord-command-line, -fno-record-command-line, -frecord-gcc-switches

Generate a section named ".GCC.command.line" containing the
driver command-line. After linking, the section may contain multiple command
lines, which will be individually terminated by null bytes. Separate arguments
within a command line are combined with spaces; spaces and backslashes within an
argument are escaped with backslashes. This format differs from the format of
the equivalent section produced by GCC with the -frecord-gcc-switches flag.
This option is currently only supported on ELF targets.

.. option:: -freflection, -fno-reflection

Enable C++26 reflection

.. option:: -freg-struct-return

Override the default ABI to return small structs in registers

.. option:: -fregister-global-dtors-with-atexit, -fno-register-global-dtors-with-atexit

Use atexit or __cxa_atexit to register global destructors

.. option:: -fretain-comments-from-system-headers

.. option:: -frewrite-imports, -fno-rewrite-imports

.. option:: -frewrite-includes, -fno-rewrite-includes

.. option:: -fropi, -fno-ropi

Generate read-only position independent code (ARM only)

.. option:: -frounding-math, -fno-rounding-math

.. option:: -frtlib-defaultlib, -fno-rtlib-defaultlib

On Windows, emit /defaultlib: directives to link compiler-rt libraries (default)

.. option:: -frtti, -fno-rtti

.. option:: -frtti-data, -fno-rtti-data

.. option:: -frwpi, -fno-rwpi

Generate read-write position independent code (ARM only)

.. option:: -fsafe-buffer-usage-suggestions, -fno-safe-buffer-usage-suggestions

Display suggestions to update code associated with -Wunsafe-buffer-usage warnings

.. option:: -fsample-profile-use-profi, -fno-sample-profile-use-profi

Infer block and edge counts. If the profiles have errors or missing
               blocks caused by sampling, profile inference (profi) can convert
               basic block counts to branch probabilities to fix them by extended
               and re-engineered classic MCMF (min-cost max-flow) approach.

.. option:: -fsanitize-debug-trap-reasons=<arg>, -fno-sanitize-debug-trap-reasons (equivalent to -fsanitize-debug-trap-reasons=none), -fsanitize-debug-trap-reasons (equivalent to -fsanitize-debug-trap-reasons=detailed)

Set how trap reasons are emitted. \`none\` - Not emitted. This gives the smallest debug info; \`basic\` - Emit a fixed trap message per check type. This increases the debug info size but not as much as \`detailed\`; \`detailed\` - Emit a more detailed trap message. This increases the debug info size the most. Default is \`detailed\`. <arg> must be 'none', 'basic' or 'detailed'.

.. option:: -fsanitize-memory-param-retval, -fno-sanitize-memory-param-retval

Enable detection of uninitialized parameters and return values

.. option:: -fsanitize-stable-abi, -fno-sanitize-stable-abi

Stable  ABI instrumentation for sanitizer runtime. Default: Conventional

.. option:: -fsave-optimization-record, -fno-save-optimization-record

Generate a YAML optimization record file

.. program:: clang1
.. option:: -fsave-optimization-record=<format>
.. program:: clang

Generate an optimization record file in a specific format

.. option:: -fseh-exceptions

Use SEH style exceptions

.. option:: -fsemantic-interposition, -fno-semantic-interposition

Enable semantic interposition. Semantic interposition allows for the
interposition of a symbol by another at runtime, thus preventing a range of
inter-procedural optimisation.

.. option:: -fseparate-named-sections, -fno-separate-named-sections

Use separate unique sections for named sections (ELF Only)

.. option:: -fshort-enums, -fno-short-enums

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

.. option:: -fshort-wchar, -fno-short-wchar

Force wchar_t to be a short unsigned int

.. option:: -fshow-column, -fno-show-column

.. option:: -fshow-overloads=<arg>

Which overload candidates to show when overload resolution fails. Defaults to 'all'. <arg> must be 'best' or 'all'.

.. option:: -fshow-source-location, -fno-show-source-location

.. option:: -fsignaling-math, -fno-signaling-math

.. option:: -fsigned-bitfields

.. option:: -fsigned-char, -fno-signed-char, --signed-char

char is signed

.. option:: -fsigned-zeros, -fno-signed-zeros

.. option:: -fsized-deallocation, -fno-sized-deallocation

Enable C++14 sized global deallocation functions

.. option:: -fsjlj-exceptions

Use SjLj style exceptions

.. option:: -fskip-odr-check-in-gmf, -fno-skip-odr-check-in-gmf

Skip ODR checks for decls in the global module fragment.

.. option:: -fslp-vectorize, -fno-slp-vectorize, -ftree-slp-vectorize

Enable the superword-level parallelism vectorization passes

.. option:: -fspell-checking, -fno-spell-checking

.. option:: -fspell-checking-limit=<arg>

Set the maximum number of times to perform spell checking on unrecognized identifiers (0 = no limit)

.. option:: -fsplit-dwarf-inlining, -fno-split-dwarf-inlining

Provide minimal debug info in the object/executable to facilitate online symbolication/stack traces in the absence of .dwo/.dwp files when using Split DWARF

.. option:: -fsplit-lto-unit, -fno-split-lto-unit

Enables splitting of the LTO unit

.. option:: -fsplit-machine-functions, -fno-split-machine-functions

Enable late function splitting using profile information (x86 and aarch64 ELF)

.. option:: -fsplit-stack, -fno-split-stack

Use segmented stack

.. option:: -fstack-clash-protection, -fno-stack-clash-protection

Instrument stack allocation to prevent stack clash attacks

.. option:: -fstack-protector, -fno-stack-protector

Enable stack protectors for some functions vulnerable to stack smashing. This uses a loose heuristic which considers functions vulnerable if they contain a char (or 8bit integer) array or constant sized calls to alloca , which are of greater size than ssp-buffer-size (default: 8 bytes). All variable sized calls to alloca are considered vulnerable. A function with a stack protector has a guard value added to the stack frame that is checked on function exit. The guard value must be positioned in the stack frame such that a buffer overflow from a vulnerable variable will overwrite the guard value before overwriting the function's return address. The reference stack guard value is stored in a global variable.

.. option:: -fstack-protector-all

Enable stack protectors for all functions

.. option:: -fstack-protector-strong

Enable stack protectors for some functions vulnerable to stack smashing. Compared to -fstack-protector, this uses a stronger heuristic that includes functions containing arrays of any size (and any type), as well as any calls to alloca or the taking of an address from a local variable

.. option:: -fstack-size-section, -fno-stack-size-section

Emit section containing metadata on function stack sizes

.. option:: -fstack-usage

Emit .su file containing information on function stack sizes

.. option:: -fstandalone-debug, -fno-limit-debug-info, -fno-standalone-debug

Emit full debug info for all types used by the program

.. option:: -fstrict-aliasing, -fno-strict-aliasing

Enable optimizations based on strict aliasing rules

.. program:: clang1
.. option:: -fstrict-bool, -fno-strict-bool
.. program:: clang

Enable optimizations based on bool bit patterns never being anything other than 0 or 1

.. option:: -fstrict-enums, -fno-strict-enums

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

.. option:: -fstrict-flex-arrays=<n>

If ``<n>`` is equal to 0, any trailing array member is considered a flexible array.
             If ``<n>`` is equal to 1, trailing array members of size 0, 1 or undefined are considered flexible arrays.
             If ``<n>`` is equal to 2, trailing array members of size 0 or undefined are considered flexible arrays.
             If ``<n>`` is equal to 3, only trailing array members of undefined size are considered flexible arrays. <n> must be '0', '1', '2' or '3'.

.. option:: -fstrict-float-cast-overflow, -fno-strict-float-cast-overflow

Assume that overflowing float-to-int casts are undefined (default)

.. option:: -fstrict-overflow, -fno-strict-overflow

.. option:: -fstrict-return, -fno-strict-return

.. option:: -fstrict-vtable-pointers, -fno-strict-vtable-pointers

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

.. option:: -fstruct-path-tbaa, -fno-struct-path-tbaa

.. option:: -fswift-async-fp=<option>

Control emission of Swift async extended frame info. <option> must be 'auto', 'always' or 'never'.

.. option:: -fsymbol-partition=<arg>

.. option:: -ftabstop=<arg>

.. option:: -ftemplate-backtrace-limit=<arg>

Set the maximum number of entries to print in a template instantiation backtrace (0 = no limit)

.. option:: -ftemplate-depth=<arg>, -ftemplate-depth-<arg>

Set the maximum depth of recursive template instantiation

.. option:: -ftemporal-profile

Generate instrumented code to collect temporal information

.. option:: -ftest-coverage, -fno-test-coverage

Produce gcov notes files (\*.gcno)

.. option:: -fthin-link-bitcode=<arg>

Write minimized bitcode to <file> for the ThinLTO thin link only

.. option:: -fthinlto-distributor=<path>

Path to the ThinLTO distributor process. If specified, ThinLTO backend compilations will be distributed by LLD

.. option:: -fthinlto-index=<arg>

Perform ThinLTO importing using provided function summary index

.. option:: -fthreadsafe-statics, -fno-threadsafe-statics

.. option:: -ftime-report

.. option:: -ftime-report-json

.. program:: clang1
.. option:: -ftime-report=<arg>
.. program:: clang

(For new pass manager) 'per-pass': one report for each pass; 'per-pass-run': one report for each pass invocation. <arg> must be 'per-pass' or 'per-pass-run'.

.. option:: -ftime-trace


Turn on time profiler. Generates JSON file based on output filename. Results
can be analyzed with chrome://tracing or `Speedscope App
<https://www.speedscope.app>`_ for flamegraph visualization.

.. option:: -ftime-trace-granularity=<arg>

Minimum time granularity (in microseconds) traced by time profiler

.. option:: -ftime-trace-verbose<arg>

Make time trace capture verbose event details (e.g. source filenames). This can increase the size of the output by 2-3 times

.. program:: clang1
.. option:: -ftime-trace=<arg>
.. program:: clang

Similar to -ftime-trace. Specify the JSON file or a directory which will contain the JSON file

.. option:: -ftls-model=<arg>

 <arg> must be 'global-dynamic', 'local-dynamic', 'initial-exec' or 'local-exec'.

.. option:: -ftrap-function=<arg>

Issue call to specified function rather than a trap instruction

.. option:: -ftrapping-math, -fno-trapping-math

.. option:: -ftrapv

Trap on integer overflow

.. option:: -ftrapv-handler <arg>

.. program:: clang1
.. option:: -ftrapv-handler=<function name>
.. program:: clang

Specify the function to be called on overflow

.. option:: -ftrigraphs, -fno-trigraphs, -trigraphs, --trigraphs

Process trigraph sequences

.. option:: -ftrivial-auto-var-init-max-size=<arg>

Stop initializing trivial automatic stack variables if var size exceeds the specified number of instances (in bytes)

.. option:: -ftrivial-auto-var-init-stop-after=<arg>

Stop initializing trivial automatic stack variables after the specified number of instances

.. option:: -ftrivial-auto-var-init=<arg>

Initialize trivial automatic stack variables. Defaults to 'uninitialized'. <arg> must be 'uninitialized', 'zero' or 'pattern'.

.. option:: -funified-lto, -fno-unified-lto

Use the unified LTO pipeline

.. option:: -funique-basic-block-section-names, -fno-unique-basic-block-section-names

Use unique names for basic block sections (ELF Only)

.. option:: -funique-internal-linkage-names, -fno-unique-internal-linkage-names

Uniqueify Internal Linkage Symbol Names by appending the MD5 hash of the module path

.. option:: -funique-section-names, -fno-unique-section-names

.. option:: -funique-source-file-identifier=<arg>

Specify the source file identifier for -funique-source-file-names; uses the source file path if not specified

.. option:: -funique-source-file-names, -fno-unique-source-file-names

Allow the compiler to assume that each translation unit has a unique source file identifier (see -funique-source-file-identifier) at link time

.. option:: -funroll-loops, -fno-unroll-loops

Turn on loop unroller

.. option:: -funsafe-math-optimizations, -fno-unsafe-math-optimizations

Allow unsafe floating-point math optimizations which may decrease precision

.. option:: -funsigned-bitfields

.. option:: -funsigned-char, -fno-unsigned-char, --unsigned-char

.. option:: -funwind-tables, -fno-unwind-tables

.. option:: -fuse-cxa-atexit, -fno-use-cxa-atexit

.. option:: -fuse-init-array, -fno-use-init-array

.. option:: -fuse-ld=<arg>

.. option:: -fuse-line-directives, -fno-use-line-directives

Use #line in preprocessed output

.. option:: -fvalidate-ast-input-files-content

Compute and store the hash of input files used to build an AST. Files with mismatching mtime's are considered valid if both contents is identical

.. option:: -fveclib=<arg>

Use the given vector functions library.
  Note: -fveclib={ArmPL,SLEEF,libmvec} implies -fno-math-errno.
  Note: -fveclib=libmvec on AArch64 requires GLIBC 2.40 or newer. <arg> must be 'Accelerate', 'libmvec', 'MASSV', 'SVML', 'SLEEF', 'Darwin_libsystem_m', 'ArmPL', 'AMDLIBM' or 'none'.

.. option:: -fvectorize, -fno-vectorize, -ftree-vectorize

Enable the loop vectorization passes

.. option:: -fverbose-asm, -dA, -fno-verbose-asm

Generate verbose assembly output

.. option:: -fvirtual-function-elimination, -fno-virtual-function-elimination

Enables dead virtual function elimination optimization. Requires -flto=full

.. option:: -fvisibility-dllexport=<arg>

The visibility for dllexport definitions. If Keep is specified the visibility is not adjusted \[-fvisibility-from-dllstorageclass\]. <arg> must be 'keep', 'hidden', 'protected' or 'default'.

.. option:: -fvisibility-externs-dllimport=<arg>

The visibility for dllimport external declarations. If Keep is specified the visibility is not adjusted \[-fvisibility-from-dllstorageclass\]. <arg> must be 'keep', 'hidden', 'protected' or 'default'.

.. option:: -fvisibility-externs-nodllstorageclass=<arg>

The visibility for external declarations without an explicit DLL storage class. If Keep is specified the visibility is not adjusted \[-fvisibility-from-dllstorageclass\]. <arg> must be 'keep', 'hidden', 'protected' or 'default'.

.. option:: -fvisibility-from-dllstorageclass, -fno-visibility-from-dllstorageclass

Override the visibility of globals based on their final DLL storage class.

.. option:: -fvisibility-global-new-delete-hidden

Give global C++ operator new and delete declarations hidden visibility

.. option:: -fvisibility-global-new-delete=<arg>

The visibility for global C++ operator new and delete declarations. If 'source' is specified the visibility is not adjusted. <arg> must be 'force-default', 'force-protected', 'force-hidden' or 'source'.

.. option:: -fvisibility-inlines-hidden, -fno-visibility-inlines-hidden

Give inline C++ member functions hidden visibility by default

.. option:: -fvisibility-inlines-hidden-static-local-var, -fno-visibility-inlines-hidden-static-local-var

When -fvisibility-inlines-hidden is enabled, static variables in inline C++ member functions will also be given hidden visibility by default

.. option:: -fvisibility-ms-compat

Give global types 'default' visibility and global functions and variables 'hidden' visibility by default

.. option:: -fvisibility-nodllstorageclass=<arg>

The visibility for definitions without an explicit DLL storage class. If Keep is specified the visibility is not adjusted \[-fvisibility-from-dllstorageclass\]. <arg> must be 'keep', 'hidden', 'protected' or 'default'.

.. option:: -fvisibility=<arg>

Set the default symbol visibility for all global definitions. <arg> must be 'default', 'hidden', 'internal' or 'protected'.

.. option:: -fwasm-exceptions

Use WebAssembly style exceptions

.. option:: -fwhole-program-vtables, -fno-whole-program-vtables

Enables whole-program vtable optimization. Requires -flto

.. option:: -fwin-cfg-mechanism=<arg>

Sets the mechanism to use for Control Flow Guard on Windows. <arg> must be 'automatic', 'dispatch' or 'check'.

.. option:: -fwinx64-eh-unwind=<arg>

Set x64 Windows unwind info version. <arg> must be 'v1', 'v2-best-effort', 'v2-required' or 'v3'.

.. option:: -fwinx64-eh-unwindv2=<arg>

(Legacy) Generate unwind v2 (epilog) information for x64 Windows. <arg> must be 'disabled', 'best-effort' or 'required'.

.. option:: -fwrapv, -fno-wrapv

Treat signed integer overflow as two's complement

.. option:: -fwrapv-pointer, -fno-wrapv-pointer

Treat pointer overflow as two's complement

.. option:: -fwritable-strings

Store string literals as writable data

.. option:: -fxl-pragma-pack, -fno-xl-pragma-pack

Enable IBM XL #pragma pack handling

.. option:: -fxray-always-emit-customevents, -fno-xray-always-emit-customevents

Always emit __xray_customevent(...) calls even if the containing function is not always instrumented

.. option:: -fxray-always-emit-typedevents, -fno-xray-always-emit-typedevents

Always emit __xray_typedevent(...) calls even if the containing function is not always instrumented

.. option:: -fxray-always-instrument=<arg>

DEPRECATED: Filename defining the whitelist for imbuing the 'always instrument' XRay attribute.

.. option:: -fxray-attr-list=<arg>

Filename defining the list of functions/types for imbuing XRay attributes.

.. option:: -fxray-function-groups=<arg>

Only instrument 1 of N groups

.. option:: -fxray-function-index, -fno-xray-function-index

.. option:: -fxray-ignore-loops, -fno-xray-ignore-loops

Don't instrument functions with loops unless they also meet the minimum function size

.. option:: -fxray-instruction-threshold=<arg>

Sets the minimum function size to instrument with XRay

.. option:: -fxray-instrument, -fno-xray-instrument

Generate XRay instrumentation sleds on function entry and exit

.. option:: -fxray-instrumentation-bundle=<arg>

Select which XRay instrumentation points to emit. Options: all, none, function-entry, function-exit, function, custom. Default is 'all'.  'function' includes both 'function-entry' and 'function-exit'.

.. option:: -fxray-link-deps, -fno-xray-link-deps

Link XRay runtime library when -fxray-instrument is specified (default)

.. option:: -fxray-modes=<arg>

List of modes to link in by default into XRay instrumented binaries.

.. option:: -fxray-never-instrument=<arg>

DEPRECATED: Filename defining the whitelist for imbuing the 'never instrument' XRay attribute.

.. option:: -fxray-selected-function-group=<arg>

When using -fxray-function-groups, select which group of functions to instrument. Valid range is 0 to fxray-function-groups - 1

.. option:: -fxray-shared, -fno-xray-shared

Enable shared library instrumentation with XRay

.. option:: -fzero-call-used-regs=<arg>

Clear call-used registers upon function return (AArch64/RISC-V/x86 only). <arg> must be 'skip', 'used-gpr-arg', 'used-gpr', 'used-arg', 'used', 'all-gpr-arg', 'all-gpr', 'all-arg' or 'all'.

.. option:: -fzero-initialized-in-bss, -fno-zero-initialized-in-bss

.. option:: -fzos-extensions, -fno-zos-extensions

Accept some non-standard constructs supported by the z/OS compiler

.. option:: -fzvector, -fno-zvector, -mzvector

Enable System z vector language extension

.. option:: -ignore-pch

Disable precompiled headers, overrides -emit-pch and -include-pch

.. option:: -pedantic, --pedantic, -no-pedantic, --no-pedantic

Warn on language extensions

.. option:: -pedantic-errors, --pedantic-errors

Common Offloading options
-------------------------
.. option:: -cuid=<arg>

An ID for compilation unit, which should be the same for the same compilation unit but different for different compilation units. It is used to externalize device-side static variables for single source offloading languages CUDA and HIP so that they can be accessed by the host code of the same compilation unit.

.. option:: -fgpu-default-stream=<arg>

Specify default stream. The default value is 'legacy'. (CUDA/HIP only). <arg> must be 'legacy' or 'per-thread'.

.. option:: -fgpu-defer-diag, -fno-gpu-defer-diag

Defer host/device related diagnostic messages for CUDA/HIP

.. option:: -fgpu-flush-denormals-to-zero, -fcuda-flush-denormals-to-zero, -fno-gpu-flush-denormals-to-zero

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

.. option:: -fgpu-rdc, -fcuda-rdc, -fno-gpu-rdc

Generate relocatable device code, also known as separate compilation mode

.. option:: -fgpu-sanitize, -fno-gpu-sanitize

Enable sanitizer for supported offloading devices

.. option:: -foffload-implicit-host-device-templates, -fno-offload-implicit-host-device-templates

Template functions or specializations without host, device and global attributes have implicit host device attributes (CUDA/HIP only)

.. option:: -foffload-via-llvm, -fno-offload-via-llvm

Use LLVM/Offload as portable offloading runtime.

.. option:: -fuse-cuid=<arg>

Method to generate ID's for compilation units for single source offloading languages CUDA and HIP: 'hash' (ID's generated by hashing file path and command line options) \| 'random' (ID's generated as random numbers) \| 'none' (disabled). Default is 'hash'. This option will be overridden by option '-cuid=\[ID\]' if it is specified.

.. option:: --offload-arch-tool=<arg>, --amdgpu-arch-tool=<arg>, --nvptx-arch-tool=<arg>

Tool used for detecting offloading architectures in the system.

.. option:: --offload-arch=<arg1>,<arg2>..., --cuda-gpu-arch=<arg>, --no-offload-arch=<arg1>,<arg2>...

Specify an offloading device architecture for CUDA, HIP, or OpenMP. (e.g. sm_35). If 'native' is used the compiler will detect locally installed architectures. For HIP offloading, the device architecture can be followed by target ID features delimited by a colon (e.g. gfx908:xnack+:sramecc-). May be specified more than once.

.. option:: --offload-compress, --no-offload-compress

Compress offload device binaries (HIP only)

.. option:: --offload-device-only, --cuda-device-only, -fsycl-device-only

Only compile for the offloading device.

.. option:: --offload-host-device, --cuda-compile-host-device

Compile for both the offloading host and device (default).

.. option:: --offload-host-only, --cuda-host-only, -fsycl-host-only

Only compile for the offloading host.

.. option:: --offload-jobs=<arg>

Specify the number of threads to use for device offloading tasks during compilation. Can be a positive integer or the string 'jobserver' to use the make-style jobserver from the environment.

.. option:: --offload-new-driver, --no-offload-new-driver

Use the new driver for offloading compilation.

.. option:: --offload-targets=<arg1>,<arg2>..., -fopenmp-targets=<arg1>,<arg2>..., --offload=<arg1>,<arg2>...

Specify a list of target architectures to use for offloading.

OpenCL options
--------------
.. option:: -cl-denorms-are-zero

OpenCL only. Allow denormals to be flushed to zero.

.. option:: -cl-ext=<arg1>,<arg2>...

OpenCL only. Enable or disable OpenCL extensions/optional features. The argument is a comma-separated sequence of one or more extension names, each prefixed by '+' or '-'.

.. option:: -cl-fast-relaxed-math

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

.. option:: -cl-finite-math-only

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

.. option:: -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.

.. option:: -cl-kernel-arg-info

OpenCL only. Generate kernel argument metadata.

.. option:: -cl-mad-enable

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

.. option:: -cl-no-signed-zeros

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

.. option:: -cl-no-stdinc

OpenCL only. Disables all standard includes containing non-native compiler types and functions.

.. option:: -cl-opt-disable

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

.. option:: -cl-single-precision-constant

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

.. option:: -cl-std=<arg>

OpenCL language standard to compile for. <arg> must be 'cl', 'CL', 'cl1.0', 'CL1.0', 'cl1.1', 'CL1.1', 'cl1.2', 'CL1.2', 'cl2.0', 'CL2.0', 'cl3.0', 'CL3.0', 'clc++', 'CLC++', 'clc++1.0', 'CLC++1.0', 'clc++2021' or 'CLC++2021'.

.. option:: -cl-strict-aliasing

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

.. option:: -cl-unsafe-math-optimizations

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

.. option:: --libclc-lib=<arg>

Namespec of libclc OpenCL bitcode library to link

SYCL options
------------
.. option:: -fsycl, -fno-sycl

Enable SYCL C++ extensions

.. option:: -fsycl-device-image-split=<arg>, -fsycl-device-image-split (equivalent to -fsycl-device-image-split=translation_unit)

Select the granularity at which SYCL device code is grouped into device images: kernel (one device image per kernel) \| translation_unit (one device image per translation unit) \| link_unit (one device image per linking unit). Default is 'translation_unit'. <arg> must be 'kernel', 'translation_unit' or 'link_unit'.

.. option:: -nolibsycl

Do not link the SYCL runtime library

.. option:: -sycl-std=<arg>

SYCL language standard to compile for. <arg> must be '2020', '2017', '121', '1.2.1' or 'sycl-1.2.1'.

CUDA options
------------
.. option:: --cuda-feature=<arg>

Manually specify the CUDA feature to use

.. option:: --cuda-include-ptx=<arg>, --no-cuda-include-ptx=<arg>

Include PTX for the following GPU architecture (e.g. sm_35) or 'all'. May be specified more than once.

.. option:: --cuda-noopt-device-debug, --no-cuda-noopt-device-debug

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

.. option:: --cuda-path-ignore-env

Ignore environment variables to detect CUDA installation

.. option:: --cuda-path=<arg>

CUDA installation path

.. option:: -fcuda-short-ptr, -fno-cuda-short-ptr

Use 32-bit pointers for accessing const/local/shared address spaces

.. option:: --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.

.. option:: --ptxas-path=<arg>

Path to ptxas (used for compiling CUDA code)

HIP options
-----------
.. option:: -fgpu-allow-device-init, -fno-gpu-allow-device-init

Allow device side init function in HIP (experimental)

.. option:: -fhip-emit-relocatable, -fno-hip-emit-relocatable

Compile HIP source to relocatable

.. option:: -fhip-fp32-correctly-rounded-divide-sqrt, -fno-hip-fp32-correctly-rounded-divide-sqrt

Specify that single precision floating-point divide and sqrt used in the program source are correctly rounded (HIP device compilation only)

.. option:: -fhip-kernel-arg-name, -fno-hip-kernel-arg-name

Specify that kernel argument names are preserved (HIP only)

.. option:: -fhip-new-launch-api, -fno-hip-new-launch-api

Use new kernel launching API for HIP

.. option:: --gpu-bundle-output, --no-gpu-bundle-output

Bundle output files of HIP device compilation

.. option:: --gpu-instrument-lib=<arg>

Instrument device library for HIP, which is a LLVM bitcode containing __cyg_profile_func_enter and __cyg_profile_func_exit

.. option:: --gpu-max-threads-per-block=<arg>

Default max threads per block for kernel launch bounds for HIP

.. option:: --hip-device-lib=<arg>

HIP device library

.. option:: --hip-link

Link clang-offload-bundler bundles for HIP

.. option:: --hip-path=<arg>

HIP runtime installation path, used for finding HIP version and adding HIP include path.

.. option:: --hip-version=<arg>

HIP version in the format of major.minor.patch

.. option:: --hipspv-pass-plugin=<dsopath>

path to a pass plugin for HIP to SPIR-V passes.

.. option:: --hipstdpar

Enable HIP acceleration for standard parallel algorithms

.. option:: --hipstdpar-interpose-alloc

Replace all memory allocation / deallocation calls with hipManagedMalloc / hipFree equivalents

.. option:: --hipstdpar-path=<arg>

HIP Standard Parallel Algorithm Acceleration library path, used for finding and implicitly including the library header

.. option:: --hipstdpar-prim-path=<arg>

rocPrim path, required by the HIP Standard Parallel Algorithm Acceleration library, used to implicitly include the rocPrim library

.. option:: --hipstdpar-thrust-path=<arg>

rocThrust path, required by the HIP Standard Parallel Algorithm Acceleration library, used to implicitly include the rocThrust library

.. option:: -no-hip-rt

Do not link against HIP runtime libraries

.. option:: --rocm-device-lib-path=<arg>, --hip-device-lib-path=<arg>

ROCm device library path. Alternative to rocm-path.

.. option:: --rocm-path=<arg>

ROCm installation path, used for finding and automatically linking required bitcode libraries.

HLSL options
------------
.. option:: -fhlsl-strict-availability

Enables strict availability diagnostic mode for HLSL built-in functions.

Target-dependent compilation options
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. option:: -G<size>, -G=<arg>, -msmall-data-limit=<arg>, -msmall-data-threshold=<arg>

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

.. option:: -ffixed-edi

Reserve the edi register (x86 only)

.. option:: -ffixed-r10

Reserve the r10 register (Hexagon/x86_64 only)

.. option:: -ffixed-r11

Reserve the r11 register (Hexagon/x86_64 only)

.. option:: -ffixed-r12

Reserve the r12 register (Hexagon/x86_64 only)

.. option:: -ffixed-r13

Reserve the r13 register (Hexagon/x86_64 only)

.. option:: -ffixed-r14

Reserve the r14 register (Hexagon/x86_64 only)

.. option:: -ffixed-r15

Reserve the r15 register (Hexagon/x86_64 only)

.. option:: -ffixed-r16

Reserve the r16 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r17

Reserve the r17 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r18

Reserve the r18 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r19

Reserve register r19 (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r20

Reserve the r20 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r21

Reserve the r21 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r22

Reserve the r22 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r23

Reserve the r23 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r24

Reserve the r24 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r25

Reserve the r25 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r26

Reserve the r26 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r27

Reserve the r27 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r28

Reserve the r28 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r29

Reserve the r29 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r30

Reserve the r30 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r31

Reserve the r31 register (Hexagon/x86_64 only; x86_64 requires APX EGPR)

.. option:: -ffixed-r6

Reserve register r6 (Hexagon only)

.. option:: -ffixed-r7

Reserve register r7 (Hexagon only)

.. option:: -ffixed-r8

Reserve the r8 register (Hexagon/x86_64 only)

.. option:: -ffixed-r9

Reserve the r9 register (ARM/Hexagon/x86_64 only)

.. option:: -ffixed-x1

Reserve the x1 register (AArch64/RISC-V only)

.. option:: -ffixed-x10

Reserve the x10 register (AArch64/RISC-V only)

.. option:: -ffixed-x11

Reserve the x11 register (AArch64/RISC-V only)

.. option:: -ffixed-x12

Reserve the x12 register (AArch64/RISC-V only)

.. option:: -ffixed-x13

Reserve the x13 register (AArch64/RISC-V only)

.. option:: -ffixed-x14

Reserve the x14 register (AArch64/RISC-V only)

.. option:: -ffixed-x15

Reserve the x15 register (AArch64/RISC-V only)

.. option:: -ffixed-x16

Reserve the x16 register (RISC-V only)

.. option:: -ffixed-x17

Reserve the x17 register (RISC-V only)

.. option:: -ffixed-x18

Reserve the x18 register (AArch64/RISC-V only)

.. option:: -ffixed-x19

Reserve the x19 register (RISC-V only)

.. option:: -ffixed-x2

Reserve the x2 register (AArch64/RISC-V only)

.. option:: -ffixed-x20

Reserve the x20 register (AArch64/RISC-V only)

.. option:: -ffixed-x21

Reserve the x21 register (AArch64/RISC-V only)

.. option:: -ffixed-x22

Reserve the x22 register (AArch64/RISC-V only)

.. option:: -ffixed-x23

Reserve the x23 register (AArch64/RISC-V only)

.. option:: -ffixed-x24

Reserve the x24 register (AArch64/RISC-V only)

.. option:: -ffixed-x25

Reserve the x25 register (AArch64/RISC-V only)

.. option:: -ffixed-x26

Reserve the x26 register (AArch64/RISC-V only)

.. option:: -ffixed-x27

Reserve the x27 register (AArch64/RISC-V only)

.. option:: -ffixed-x28

Reserve the x28 register (AArch64/RISC-V only)

.. option:: -ffixed-x29

Reserve the x29 register (RISC-V only)

.. option:: -ffixed-x3

Reserve the x3 register (AArch64/RISC-V only)

.. option:: -ffixed-x30

Reserve the x30 register (RISC-V only)

.. option:: -ffixed-x31

Reserve the x31 register (RISC-V only)

.. option:: -ffixed-x4

Reserve the x4 register (AArch64/RISC-V only)

.. option:: -ffixed-x5

Reserve the x5 register (AArch64/RISC-V only)

.. option:: -ffixed-x6

Reserve the x6 register (AArch64/RISC-V only)

.. option:: -ffixed-x7

Reserve the x7 register (AArch64/RISC-V only)

.. option:: -ffixed-x8

Reserve the x8 register (RISC-V only)

.. option:: -ffixed-x9

Reserve the x9 register (AArch64/RISC-V only)

.. option:: -ffuchsia-api-level=<arg>

Set Fuchsia API level

.. option:: -inline-asm=<arg>

 <arg> must be 'att' or 'intel'.

.. option:: -lifetime-safety-lifetimebound-macro=<macro>

Use the given macro name when suggesting lifetimebound attributes

.. option:: -lifetime-safety-max-cfg-blocks=<arg>

Skip LifetimeSafety analysis for functions with CFG block count exceeding this threshold. Specify 0 for no limit.

.. option:: -m16

.. option:: -m32

.. option:: -m64

.. option:: -mabi=<arg>

.. program:: clang1
.. option:: -mabi=quadword-atomics
.. program:: clang

Enable quadword atomics ABI on AIX (AIX PPC64 only). Uses lqarx/stqcx. instructions.

.. option:: -maix-struct-return

Override the default ABI for 32-bit targets to return all structs in memory, as in the Power 32-bit ABI for Linux (2011), and on AIX and Darwin.

.. option:: -maix-use-ptrgl, -mno-aix-use-ptrgl

Use ._ptrgl routine for indirect calls (AIX only)

.. option:: -maix32

.. option:: -maix64

.. option:: -malign-branch-boundary=<arg>

Specify the boundary's size to align branches

.. option:: -malign-branch=<arg1>,<arg2>...

Specify types of branches to align

.. option:: -malign-double

Align doubles to two words in structs (x86 only)

.. option:: -mamdgpu-expand-waitcnt-profiling, -mno-amdgpu-expand-waitcnt-profiling

Expand s_waitcnt instructions to help PC-sampling profilers identify memory stalls. Instead of a single waitcnt(target), emits waitcnt(N-1), waitcnt(N-2), ..., waitcnt(target). (AMDGPU only)

.. option:: -mamdgpu-ieee, -mno-amdgpu-ieee

Sets the IEEE bit in the expected default floating point  mode register. Floating point opcodes that support exception flag gathering quiet and propagate signaling NaN inputs per IEEE 754-2008. This option changes the ABI. (AMDGPU only)

.. option:: -mamdgpu-precise-memory-op, -mno-amdgpu-precise-memory-op

Enable precise memory mode (AMDGPU only)

.. option:: -mapx-inline-asm-use-gpr32

Enable use of GPR32 in inline assembly for APX

.. option:: -march=<arg>

For a list of available architectures for the target use '-mcpu=help'

.. option:: -marm64x<arg>

Build as a hybrid ARM64X object/image

.. option:: -masm=<arg>

.. option:: -mbackchain, -mno-backchain

Link stack frames through backchain on System Z

.. option:: -mbig-endian, -EB

.. option:: -mbranch-protection=<arg>

Enforce targets of indirect branches and function returns

.. option:: -mbranches-within-32B-boundaries

Align selected branches (fused, jcc, jmp) within 32-byte boundary

.. option:: -mcf-branch-label-scheme=<arg>

Select label scheme for branch control-flow architecture protection. <arg> must be 'unlabeled' or 'func-sig'.

.. option:: -mcmodel=<arg>

.. option:: -mcode-object-version=<arg>

Specify code object ABI version. Defaults to 6. (AMDGPU only). <arg> must be 'none', '4', '5' or '6'.

.. option:: -mconsole<arg>

.. option:: -mconstructor-aliases, -mno-constructor-aliases

Enable emitting complete constructors and destructors as aliases when possible

.. program:: clang1
.. option:: -mcpu=<arg>, -mv5 (equivalent to -mcpu=hexagonv5), -mv55 (equivalent to -mcpu=hexagonv55), -mv60 (equivalent to -mcpu=hexagonv60), -mv62 (equivalent to -mcpu=hexagonv62), -mv65 (equivalent to -mcpu=hexagonv65), -mv66 (equivalent to -mcpu=hexagonv66), -mv67 (equivalent to -mcpu=hexagonv67), -mv67t (equivalent to -mcpu=hexagonv67t), -mv68 (equivalent to -mcpu=hexagonv68), -mv69 (equivalent to -mcpu=hexagonv69), -mv71 (equivalent to -mcpu=hexagonv71), -mv71t (equivalent to -mcpu=hexagonv71t), -mv73 (equivalent to -mcpu=hexagonv73), -mv75 (equivalent to -mcpu=hexagonv75), -mv79 (equivalent to -mcpu=hexagonv79), -mv81 (equivalent to -mcpu=hexagonv81)
.. program:: clang

For a list of available CPUs for the target use '-mcpu=help'

.. option:: -mcrc, -mno-crc

Allow use of CRC instructions (ARM/Mips only)

.. option:: -mdaz-ftz, -mno-daz-ftz

Globally set the denormals-are-zero (DAZ) and flush-to-zero (FTZ) bits in the floating-point control register on program startup

.. option:: -mdefault-build-attributes<arg>, -mno-default-build-attributes<arg>

.. option:: -mdefault-visibility-export-mapping=<arg>

Mapping between default visibility and export. <arg> must be 'none', 'explicit' or 'all'.

.. option:: -mdll<arg>

.. option:: -mdouble-float

.. option:: -mdouble=<n

Force double to be <n> bits. <n must be '32' or '64'.

.. option:: -mdynamic-no-pic<arg>

.. option:: -meabi <arg>

Set EABI type. Default depends on triple). <arg> must be 'default', '4', '5' or 'gnu'.

.. option:: -menable-experimental-extensions

Enable use of experimental RISC-V extensions.

.. option:: -mexperimental-mtune-syntax, -mno-experimental-mtune-syntax

Enable experimental syntax for the '-mtune' flag (RISC-V only)

.. option:: -mfentry

Insert calls to fentry at function entry (x86/SystemZ only)

.. option:: -mfloat-abi=<arg>

 <arg> must be 'soft', 'softfp' or 'hard'.

.. option:: -mfpmath=<arg>

.. option:: -mfpu=<arg>

.. option:: -mfunction-return=<arg>

Replace returns with jumps to \`\`__x86_return_thunk\`\` (x86 only, error otherwise). <arg> must be 'keep' or 'thunk-extern'.

.. option:: -mgeneral-regs-only

Generate code which only uses the general purpose registers (AArch64/x86 only)

.. option:: -mglobal-merge, -mno-global-merge

Enable merging of globals

.. option:: -mguard=<arg>

Enable or disable Control Flow Guard checks and guard tables emission. <arg> must be 'none', 'cf' or 'cf-nochecks'.

.. option:: -mhard-float

.. option:: -mharden-sls=<arg>

Select straight-line speculation hardening scope (ARM/AArch64/X86 only). <arg> must be: all, none, retbr(ARM/AArch64), blr(ARM/AArch64), comdat(ARM/AArch64), nocomdat(ARM/AArch64), return(X86), indirect-jmp(X86)

.. option:: -mhwdiv=<arg>, --mhwdiv <arg>, --mhwdiv=<arg>

.. option:: -mhwmult=<arg>

.. option:: -miamcu, -mno-iamcu

Use Intel MCU ABI

.. option:: -mignore-xcoff-visibility

Not emit the visibility attribute for asm in AIX OS or give all symbols 'unspecified' visibility in XCOFF object file

.. option:: -mimplicit-float, -mno-implicit-float

Generate implicit floating point or vector instructions

.. option:: -mimplicit-it=<arg>

.. option:: -mincremental-linker-compatible, -mno-incremental-linker-compatible

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

.. option:: -mindirect-branch-cs-prefix

Add cs prefix to call and jmp to indirect thunk

.. option:: -mios-simulator-version-min=<arg>, -miphonesimulator-version-min=<arg>

.. option:: -mios-version-min=<arg>, -miphoneos-version-min=<arg>

Set iOS deployment target

.. option:: -mkernel

.. option:: -mlarge-data-threshold=<arg>

.. option:: -mlink-builtin-bitcode-postopt, -mno-link-builtin-bitcode-postopt

Link builtin bitcodes after the optimization pipeline

.. option:: -mlinker-version=<arg>

.. option:: -mlittle-endian, -EL

.. option:: -mlong-calls, -mno-long-calls

Generate branches with extended addressability, usually via indirect jumps.

.. option:: -mlvi-cfi, -mno-lvi-cfi

Enable only control-flow mitigations for Load Value Injection (LVI)

.. option:: -mlvi-hardening, -mno-lvi-hardening

Enable all mitigations for Load Value Injection (LVI)

.. option:: -mmacos-version-min=<arg>, -mmacosx-version-min=<arg>

Set macOS deployment target

.. option:: -mmcu=<arg>

.. option:: -mms-bitfields, -mno-ms-bitfields

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

.. option:: -mno-gather

Disable generation of gather instructions in auto-vectorization(x86 only)

.. option:: -mno-scatter

Disable generation of scatter instructions in auto-vectorization(x86 only)

.. option:: -mnop-mcount

Generate mcount/__fentry__ calls as nops. To activate they need to be patched in.

.. option:: -momit-leaf-frame-pointer, -mno-omit-leaf-frame-pointer

Omit frame pointer setup for leaf functions

.. option:: -moslib=<arg>

.. option:: -moutline, -mno-outline

Enable function outlining (AArch64,Arm,RISC-V,X86 only)

.. option:: -mpacked-stack, -mno-packed-stack

Use packed stack layout (SystemZ only).

.. option:: -mpad-max-prefix-size=<arg>

Specify maximum number of prefixes to use for padding

.. option:: -mpic-data-is-text-relative, -mno-pic-data-is-text-relative

Assume data segments are relative to text segment

.. option:: -mprefer-vector-width=<arg>

Specifies preferred vector width for auto-vectorization. Defaults to 'none' which allows target specific decisions.

.. option:: -mprintf-kind=<arg>

Specify the printf lowering scheme (AMDGPU only), allowed values are "hostcall"(printing happens during kernel execution, this scheme relies on hostcalls which require system to support pcie atomics) and "buffered"(printing happens after all kernel threads exit, this uses a printf buffer and does not rely on pcie atomic support). <arg> must be 'hostcall' or 'buffered'.

.. option:: -mqdsp6-compat

Enable hexagon-qdsp6 backward compatibility

.. option:: -mrecip

Equivalent to '-mrecip=all'

.. program:: clang1
.. option:: -mrecip=<arg1>,<arg2>...
.. program:: clang

Control use of approximate reciprocal and reciprocal square root instructions followed by <n> iterations of Newton-Raphson refinement. <value> = ( \['!'\] \['vec-'\] ('rcp'\|'sqrt') \[('h'\|'s'\|'d')\] \[':'<n>\] ) \| 'all' \| 'default' \| 'none'

.. option:: -mrecord-mcount

Generate a __mcount_loc section entry for each __fentry__ call.

.. option:: -mred-zone, -mno-red-zone

.. option:: -mregnames, -mno-regnames

Use full register names when writing assembly output

.. option:: -mregparm=<arg>

.. option:: -mrelax, -mno-relax

Enable linker relaxation

.. option:: -mrelax-all, -mno-relax-all

(integrated-as) Relax all machine instructions

.. option:: -mreserve-frame-pointer-reg, -mno-reserve-frame-pointer-reg

Reserve the frame pointer register even if the function doesn't have a frame

.. option:: -mretpoline, -mno-retpoline

.. option:: -mrtd, -mno-rtd

Make StdCall calling convention the default

.. option:: -mrvv-vector-bits=<arg>

Specify the size in bits of an RVV vector register. Defaults to the vector length agnostic value of "scalable". Accepts power of 2 values between 64 and 65536. Also accepts "zvl" to use the value implied by -march/-mcpu. The value will be reflected in __riscv_v_fixed_vlen preprocessor define (RISC-V only)

.. option:: -msave-reg-params

Save arguments passed by registers to ABI-defined stack positions

.. option:: -mscalar-strict-align, -mno-scalar-strict-align

Force all scalar memory accesses to be aligned (RISC-V only)

.. option:: -mscs-reg=<arg>

Register holding the shadow call stack pointer: one of the callee-saved registers r16-r27, default r18 (Hexagon only). The chosen register must also be reserved with -ffixed-<reg>.

.. option:: -mseses, -mno-seses

Enable speculative execution side effect suppression (SESES). Includes LVI control flow integrity mitigations

.. option:: -msign-return-address=<arg>

Select return address signing scope. <arg> must be 'none', 'all' or 'non-leaf'.

.. option:: -msim

.. option:: -msingle-float

.. option:: -mskip-rax-setup, -mno-skip-rax-setup

Skip setting up RAX register when passing variable arguments (x86 only)

.. option:: -msoft-float, -mno-soft-float

Use software floating point

.. option:: -mspeculative-load-hardening, -mno-speculative-load-hardening

.. option:: -msse2avx

Specify that the assembler should encode SSE instructions with VEX prefix

.. option:: -mstack-alignment=<arg>

Set the stack alignment

.. option:: -mstack-arg-probe, -mno-stack-arg-probe

Enable stack probes

.. option:: -mstack-probe-size=<arg>

Set the stack probe size

.. option:: -mstack-protector-guard-offset=<arg>

Use the given offset for addressing the stack-protector guard

.. option:: -mstack-protector-guard-record

Generate a __stack_protector_loc section entry for each load of the stack-protector guard address.

.. option:: -mstack-protector-guard-reg=<arg>

Use the given reg for addressing the stack-protector guard

.. option:: -mstack-protector-guard-symbol=<arg>

Use the given symbol for addressing the stack-protector guard

.. option:: -mstack-protector-guard-value-width=<arg>

Set the width of the stack-protector guard variable. By default,
the width is the same as the pointer width.  Currently only supported on AArch64
targets.  Only the values "4" and "8" are currently supported.  This currently
only modifies the size of accesses to the global variable, not the value
stored on the stack.

.. option:: -mstack-protector-guard=<arg>

Use the given guard (global, tls) for addressing the stack-protector guard

.. option:: -mstackrealign, -mno-stackrealign

Force realign the stack at entry to every function

.. option:: -mstrict-align, -mno-strict-align

Force all memory accesses to be aligned (AArch64/LoongArch/RISC-V only)

.. option:: -msvr4-struct-return

Override the default ABI for 32-bit targets to return small structs in registers, as in the System V ABI (1995).

.. option:: -mtargetos=<arg>

Set the deployment target to be the specified OS and OS version

.. option:: -mthread-model <arg>

The thread model to use. Defaults to 'posix'). <arg> must be 'posix' or 'single'.

.. option:: -mthreads<arg>

.. option:: -mthumb, -mno-thumb

.. option:: -mtls-dialect=<arg>

Which thread-local storage dialect to use for dynamic accesses of TLS variables

.. option:: -mtls-direct-seg-refs, -mno-tls-direct-seg-refs

Enable direct TLS access through segment registers (default)

.. option:: -mtls-size=<arg>

Specify bit size of immediate TLS offsets (AArch64 ELF only): 12 (for 4KB) \| 24 (for 16MB, default) \| 32 (for 4GB) \| 48 (for 256TB, needs -mcmodel=large)

.. option:: -mtocdata, -mno-tocdata

All suitable variables will have the TOC data transformation applied

.. program:: clang1
.. option:: -mtocdata=<arg1>,<arg2>..., -mno-tocdata=<arg1>,<arg2>...
.. program:: clang

Specifies a list of variables to which the TOC data transformation will be applied.

.. program:: clang1
.. option:: -mtune=<arg>
.. program:: clang

Only supported on AArch64, PowerPC, RISC-V, SPARC, SystemZ, and X86

.. option:: -mtvos-version-min=<arg>, -mappletvos-version-min=<arg>

.. option:: -munaligned-access, -mno-unaligned-access

Allow memory accesses to be unaligned (AArch32/MIPSr6 only)

.. option:: -munaligned-symbols, -mno-unaligned-symbols

Expect external char-aligned symbols to be without ABI alignment (SystemZ only)

.. option:: -municode<arg>

.. option:: -mvector-strict-align, -mno-vector-strict-align

Force all vector memory accesses to be aligned (RISC-V only)

.. option:: -mvx, -mno-vx

.. option:: -mwarn-nonportable-cfstrings, -mno-warn-nonportable-cfstrings

.. option:: -mwatchos-simulator-version-min=<arg>, -mwatchsimulator-version-min=<arg>

.. option:: -mwatchos-version-min=<arg>

.. option:: -mwavefrontsize64, -mno-wavefrontsize64

Specify wavefront size 64 mode (AMDGPU only)

.. option:: -mwindows<arg>

.. option:: -mx32

.. option:: -mxcoff-roptr, -mno-xcoff-roptr

Place constant objects with relocatable address values in the RO data section and add -bforceimprw to the linker flags (AIX only)

.. option:: -mzilsd-strict-align

Force all Zilsd/Zclsd memory accesses to be 8-byte aligned (RISC-V only)

.. option:: -mzilsd-word-align

Allow Zilsd/Zclsd memory accesses to be 4-byte aligned (RISC-V only)

.. option:: -mzos-ppa1-name, -mno-zos-ppa1-name

Emit the function name in PPA1 on z/OS

.. option:: -mzos-target=<arg>

Set the z/OS release of the runtime environment

.. option:: -regcall4

Set __regcall4 as a default calling convention to respect __regcall ABI v.4

.. option:: --wasm-opt, --no-wasm-opt

Enable the wasm-opt optimizer (default)

AARCH64
-------
.. option:: -fcall-saved-x10

Make the x10 register call-saved (AArch64 only)

.. option:: -fcall-saved-x11

Make the x11 register call-saved (AArch64 only)

.. option:: -fcall-saved-x12

Make the x12 register call-saved (AArch64 only)

.. option:: -fcall-saved-x13

Make the x13 register call-saved (AArch64 only)

.. option:: -fcall-saved-x14

Make the x14 register call-saved (AArch64 only)

.. option:: -fcall-saved-x15

Make the x15 register call-saved (AArch64 only)

.. option:: -fcall-saved-x18

Make the x18 register call-saved (AArch64 only)

.. option:: -fcall-saved-x8

Make the x8 register call-saved (AArch64 only)

.. option:: -fcall-saved-x9

Make the x9 register call-saved (AArch64 only)

.. option:: -mfix-cortex-a53-835769, -mno-fix-cortex-a53-835769

Work around Cortex-A53 erratum 835769 (AArch64 only)

.. option:: -mfix-cortex-a53-843419, -mno-fix-cortex-a53-843419

Work around Cortex-A53 erratum 843419 (AArch64 only)

.. option:: -mlr-for-calls-only

Do not allocate the LR register for general purpose usage, only for calls. (AArch64 only)

.. option:: -mmark-bti-property

Add .note.gnu.property with BTI to assembly files (AArch64 only)

.. option:: -msve-streaming-vector-bits=<arg>

Specify the size in bits of an SVE vector register in streaming mode. Defaults to the vector length agnostic value of "scalable". (AArch64 only)

.. option:: -msve-vector-bits=<arg>

Specify the size in bits of an SVE vector register. Defaults to the vector length agnostic value of "scalable". (AArch64 only)

AMDGPU
------
.. option:: -mcumode, -mno-cumode

Specify CU wavefront execution mode (AMDGPU only)

.. option:: -msramecc, -mno-sramecc

Enable SRAMECC (AMDGPU only)

.. option:: -mtgsplit, -mno-tgsplit

Enable threadgroup split execution mode (AMDGPU only)

.. option:: -mxnack, -mno-xnack

Enable XNACK (AMDGPU only)

ARM
---
.. option:: -faapcs-bitfield-load

Follows the AAPCS standard that all volatile bit-field write generates at least one load. (ARM only).

.. option:: -faapcs-bitfield-width, -fno-aapcs-bitfield-width

Follow the AAPCS standard requirement stating that volatile bit-field width is dictated by the field container type. (ARM only).

.. option:: -mcmse

Allow use of CMSE (Armv8-M Security Extensions)

.. option:: -mexecute-only, -mno-execute-only, -mpure-code

Disallow generation of data access to code sections (AArch64/ARM only)

.. option:: -mfix-cmse-cve-2021-35465, -mno-fix-cmse-cve-2021-35465

Work around VLLDM erratum CVE-2021-35465 (ARM only)

.. option:: -mfix-cortex-a57-aes-1742098, -mfix-cortex-a72-aes-1655431, -mno-fix-cortex-a57-aes-1742098

Work around Cortex-A57 Erratum 1742098 (ARM only)

.. option:: -mframe-chain=<arg>

Select the frame chain model used to emit frame records (Arm only). <arg> must be 'none', 'aapcs' or 'aapcs+leaf'.

.. option:: -mno-bti-at-return-twice

Do not add a BTI instruction after a setjmp or other return-twice construct (Arm/AArch64 only)

.. option:: -mno-movt

Disallow use of movt/movw pairs (ARM only)

.. option:: -mno-neg-immediates

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

.. option:: -mnocrc

Disallow use of CRC instructions (ARM only)

.. option:: -mrestrict-it, -mno-restrict-it

Disallow generation of complex IT blocks. It is off by default.

.. option:: -mtp=<arg>

Thread pointer access method. For AArch32: 'soft' uses a function call, or 'tpidrurw', 'tpidruro' or 'tpidrprw' use the three CP15 registers. 'cp15' is an alias for 'tpidruro'. For AArch64: 'tpidr_el0', 'tpidr_el1', 'tpidr_el2', 'tpidr_el3' or 'tpidrro_el0' use the five system registers. 'elN' is an alias for 'tpidr_elN'. <arg> must be 'soft', 'cp15', 'tpidrurw', 'tpidruro', 'tpidrprw', 'el0', 'el1', 'el2', 'el3', 'tpidr_el0', 'tpidr_el1', 'tpidr_el2', 'tpidr_el3', 'tpidrro_el0' or 'auto'.

Hexagon
-------
.. option:: -mcabac

Enable CABAC instructions

.. option:: -mhvx-ieee-fp, -mno-hvx-ieee-fp

Enable Hexagon HVX IEEE floating-point

.. option:: -mieee-rnd-near

.. option:: -mmemops, -mno-memops

Enable generation of memop instructions

.. option:: -mnvj, -mno-nvj

Enable generation of new-value jumps

.. option:: -mnvs, -mno-nvs

Enable generation of new-value stores

.. option:: -mpackets, -mno-packets

Enable generation of instruction packets

SPARC
-----
.. option:: -ffixed-g1

Reserve the G1 register (SPARC only)

.. option:: -ffixed-g2

Reserve the G2 register (SPARC only)

.. option:: -ffixed-g3

Reserve the G3 register (SPARC only)

.. option:: -ffixed-g4

Reserve the G4 register (SPARC only)

.. option:: -ffixed-g5

Reserve the G5 register (SPARC only)

.. option:: -ffixed-g6

Reserve the G6 register (SPARC only)

.. option:: -ffixed-g7

Reserve the G7 register (SPARC only)

.. option:: -ffixed-i0

Reserve the I0 register (SPARC only)

.. option:: -ffixed-i1

Reserve the I1 register (SPARC only)

.. option:: -ffixed-i2

Reserve the I2 register (SPARC only)

.. option:: -ffixed-i3

Reserve the I3 register (SPARC only)

.. option:: -ffixed-i4

Reserve the I4 register (SPARC only)

.. option:: -ffixed-i5

Reserve the I5 register (SPARC only)

.. option:: -ffixed-l0

Reserve the L0 register (SPARC only)

.. option:: -ffixed-l1

Reserve the L1 register (SPARC only)

.. option:: -ffixed-l2

Reserve the L2 register (SPARC only)

.. option:: -ffixed-l3

Reserve the L3 register (SPARC only)

.. option:: -ffixed-l4

Reserve the L4 register (SPARC only)

.. option:: -ffixed-l5

Reserve the L5 register (SPARC only)

.. option:: -ffixed-l6

Reserve the L6 register (SPARC only)

.. option:: -ffixed-l7

Reserve the L7 register (SPARC only)

.. option:: -ffixed-o0

Reserve the O0 register (SPARC only)

.. option:: -ffixed-o1

Reserve the O1 register (SPARC only)

.. option:: -ffixed-o2

Reserve the O2 register (SPARC only)

.. option:: -ffixed-o3

Reserve the O3 register (SPARC only)

.. option:: -ffixed-o4

Reserve the O4 register (SPARC only)

.. option:: -ffixed-o5

Reserve the O5 register (SPARC only)

.. option:: -mfix-gr712rc

Enable workarounds for GR712RC errata

.. option:: -mfix-ut700

Enable workarounds for UT700 errata

.. program:: clang1
.. option:: -mfpu, -mno-fpu
.. program:: clang

.. option:: -mfsmuld, -mno-fsmuld

.. option:: -mhard-quad-float

.. option:: -mpopc, -mno-popc

.. option:: -msoft-quad-float

.. option:: -mv8plus, -mno-v8plus

Enable V8+ mode, allowing use of 64-bit V9 instructions in 32-bit code

.. option:: -mvis, -mno-vis

.. option:: -mvis2, -mno-vis2

.. option:: -mvis3, -mno-vis3

Hexagon HVX
-----------
.. option:: -mhvx, -mno-hvx

Enable Hexagon Vector eXtensions

.. option:: -mhvx-length=<arg>

Set Hexagon Vector Length. <arg> must be '64B' or '128B'.

.. option:: -mhvx-qfloat, -mno-hvx-qfloat

Enable Hexagon HVX QFloat instructions

.. program:: clang1
.. option:: -mhvx-qfloat=<arg>
.. program:: clang

Enable Hexagon HVX QFloat instructions with mode: strict-ieee, ieee, lossy, legacy (v79+)

.. program:: clang1
.. option:: -mhvx=<arg>
.. program:: clang

Enable Hexagon Vector eXtensions

M68k
----
.. option:: -ffixed-a0

Reserve the a0 register (M68k only)

.. option:: -ffixed-a1

Reserve the a1 register (M68k only)

.. option:: -ffixed-a2

Reserve the a2 register (M68k only)

.. option:: -ffixed-a3

Reserve the a3 register (M68k only)

.. option:: -ffixed-a4

Reserve the a4 register (M68k only)

.. option:: -ffixed-a5

Reserve the a5 register (M68k only)

.. option:: -ffixed-a6

Reserve the a6 register (M68k only)

.. option:: -ffixed-d0

Reserve the d0 register (M68k only)

.. option:: -ffixed-d1

Reserve the d1 register (M68k only)

.. option:: -ffixed-d2

Reserve the d2 register (M68k only)

.. option:: -ffixed-d3

Reserve the d3 register (M68k only)

.. option:: -ffixed-d4

Reserve the d4 register (M68k only)

.. option:: -ffixed-d5

Reserve the d5 register (M68k only)

.. option:: -ffixed-d6

Reserve the d6 register (M68k only)

.. option:: -ffixed-d7

Reserve the d7 register (M68k only)

.. option:: -m68000

.. option:: -m68010

.. option:: -m68020

.. option:: -m68030

.. option:: -m68040

.. option:: -m68060

.. option:: -m68881

MIPS
----
.. option:: -mabicalls, -mno-abicalls

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

.. option:: -mabs=<arg>

.. option:: -mcheck-zero-division, -mno-check-zero-division

.. option:: -mcompact-branches=<arg>

.. option:: -mdsp, -mno-dsp

.. option:: -mdspr2, -mno-dspr2

.. option:: -membedded-data, -mno-embedded-data

Place constants in the .rodata section instead of the .sdata section even if they meet the -G <size> threshold (MIPS)

.. option:: -mextern-sdata, -mno-extern-sdata

Assume that externally defined data is in the small data if it meets the -G <size> threshold (MIPS)

.. option:: -mfix-r5900, -mno-fix-r5900

Enable R5900 short loop erratum fix

.. option:: -mfix4300

.. option:: -mfp32

Use 32-bit floating point registers (MIPS only)

.. option:: -mfp64

Use 64-bit floating point registers (MIPS only)

.. option:: -mginv, -mno-ginv

.. option:: -mgpopt, -mno-gpopt

Use GP relative accesses for symbols known to be in a small data section (MIPS)

.. option:: -mindirect-jump=<arg>

Change indirect jump instructions to inhibit speculation

.. option:: -mips16

.. option:: -mldc1-sdc1, -mno-ldc1-sdc1

.. option:: -mlocal-sdata, -mno-local-sdata

Extend the -G behaviour to object local data (MIPS)

.. option:: -mmadd4, -mno-madd4

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

.. option:: -mmicromips, -mno-micromips

.. option:: -mmsa, -mno-msa

Enable MSA ASE (MIPS only)

.. option:: -mmt, -mno-mt

Enable MT ASE (MIPS only)

.. option:: -mnan=<arg>

.. option:: -mno-mips16

.. option:: -mvirt, -mno-virt

.. option:: -mxgot, -mno-xgot

PowerPC
-------
.. option:: -maix-shared-lib-tls-model-opt

For shared library loaded with the main program, change local-dynamic access(es) to initial-exec access(es) at the function level (AIX 64-bit only).

.. option:: -maix-small-local-dynamic-tls

Produce a faster access sequence for local-dynamic TLS variables where the offset from the TLS base is encoded as an immediate operand (AIX 64-bit only). This access sequence is not used for variables larger than 32KB.

.. option:: -maix-small-local-exec-tls

Produce a faster access sequence for local-exec TLS variables where the offset from the TLS base is encoded as an immediate operand (AIX 64-bit only). This access sequence is not used for variables larger than 32KB.

.. option:: -maltivec, -mno-altivec

Enable AltiVec vector initializer syntax

.. option:: -mcmpb, -mno-cmpb

.. option:: -mcrbits, -mno-crbits

Control the CR-bit tracking feature on PowerPC. \`\`-mcrbits\`\` (the enablement of CR-bit tracking support) is the default for POWER8 and above, as well as for all other CPUs when optimization is applied (-O2 and above).

.. option:: -mcrypto, -mno-crypto

.. option:: -mdirect-move, -mno-direct-move

.. option:: -mefpu2

.. option:: -mfloat128, -mno-float128

.. option:: -mfprnd, -mno-fprnd

.. option:: -mhtm, -mno-htm

.. option:: -minvariant-function-descriptors, -mno-invariant-function-descriptors

.. option:: -misel, -mno-isel

.. option:: -mlongcall, -mno-longcall

.. option:: -mmfocrf, -mmfcrf, -mno-mfocrf

.. option:: -mmma, -mno-mma

.. option:: -mpaired-vector-memops, -mno-paired-vector-memops

.. option:: -mpcrel, -mno-pcrel

.. option:: -mpopcntd, -mno-popcntd

.. option:: -mpower10-vector, -mno-power10-vector

.. option:: -mpower8-vector, -mno-power8-vector

.. option:: -mpower9-vector, -mno-power9-vector

.. option:: -mprefixed, -mno-prefixed

.. option:: -mprivileged

.. option:: -mrop-protect

.. option:: -msecure-plt

.. option:: -mspe, -mno-spe

.. option:: -mvsx, -mno-vsx

WebAssembly
-----------
.. option:: -matomics, -mno-atomics

.. option:: -mbulk-memory, -mno-bulk-memory

.. option:: -mbulk-memory-opt, -mno-bulk-memory-opt

.. option:: -mcall-indirect-overlong, -mno-call-indirect-overlong

.. option:: -mcompact-imports, -mno-compact-imports

.. option:: -mexception-handling, -mno-exception-handling

.. option:: -mextended-const, -mno-extended-const

.. option:: -mfp16, -mno-fp16

.. option:: -mgc, -mno-gc

.. option:: -mmultimemory, -mno-multimemory

.. option:: -mmultivalue, -mno-multivalue

.. option:: -mmutable-globals, -mno-mutable-globals

.. option:: -mnontrapping-fptoint, -mno-nontrapping-fptoint

.. option:: -mreference-types, -mno-reference-types

.. option:: -mrelaxed-atomics, -mno-relaxed-atomics

.. option:: -mrelaxed-simd, -mno-relaxed-simd

.. option:: -msign-ext, -mno-sign-ext

.. option:: -msimd128, -mno-simd128

.. option:: -mtail-call, -mno-tail-call

.. option:: -mwide-arithmetic, -mno-wide-arithmetic

WebAssembly Driver
------------------
.. option:: -mexec-model=<arg>

Select between "command" and "reactor" executable models. Commands have a main-function which scopes the lifetime of the program. Reactors are activated and remain active until explicitly terminated. <arg> must be 'command' or 'reactor'.

X86
---
.. option:: -madx, -mno-adx

.. option:: -maes, -mno-aes

.. option:: -mamx-avx512, -mno-amx-avx512

.. option:: -mamx-bf16, -mno-amx-bf16

.. option:: -mamx-complex, -mno-amx-complex

.. option:: -mamx-fp16, -mno-amx-fp16

.. option:: -mamx-fp8, -mno-amx-fp8

.. option:: -mamx-int8, -mno-amx-int8

.. option:: -mamx-movrs, -mno-amx-movrs

.. option:: -mamx-tile, -mno-amx-tile

.. option:: -mapx-features=<arg1>,<arg2>..., -mapxf (equivalent to -mapx-features=egpr,push2pop2,ppx,ndd,ccmp,nf,zu,jmpabs), -mno-apx-features=<arg1>,<arg2>...

Enable features of APX. <arg> must be 'egpr', 'push2pop2', 'ppx', 'ndd', 'ccmp', 'nf', 'cf', 'zu' or 'jmpabs'.

.. option:: -mavx, -mno-avx

.. option:: -mavx10.1, -mno-avx10.1

.. program:: clang1
.. option:: -mavx10.2, -mno-avx10.2
.. program:: clang

.. option:: -mavx2, -mno-avx2

.. option:: -mavx512bf16, -mno-avx512bf16

.. option:: -mavx512bitalg, -mno-avx512bitalg

.. option:: -mavx512bmm, -mno-avx512bmm

.. option:: -mavx512bw, -mno-avx512bw

.. option:: -mavx512cd, -mno-avx512cd

.. option:: -mavx512dq, -mno-avx512dq

.. option:: -mavx512f, -mno-avx512f

.. option:: -mavx512fp16, -mno-avx512fp16

.. option:: -mavx512ifma, -mno-avx512ifma

.. option:: -mavx512vbmi, -mno-avx512vbmi

.. option:: -mavx512vbmi2, -mno-avx512vbmi2

.. option:: -mavx512vl, -mno-avx512vl

.. option:: -mavx512vnni, -mno-avx512vnni

.. option:: -mavx512vp2intersect, -mno-avx512vp2intersect

.. option:: -mavx512vpopcntdq, -mno-avx512vpopcntdq

.. option:: -mavxifma, -mno-avxifma

.. option:: -mavxneconvert, -mno-avxneconvert

.. option:: -mavxvnni, -mno-avxvnni

.. option:: -mavxvnniint16, -mno-avxvnniint16

.. option:: -mavxvnniint8, -mno-avxvnniint8

.. option:: -mbmi, -mno-bmi

.. option:: -mbmi2, -mno-bmi2

.. option:: -mcldemote, -mno-cldemote

.. option:: -mclflushopt, -mno-clflushopt

.. option:: -mclwb, -mno-clwb

.. option:: -mclzero, -mno-clzero

.. option:: -mcmpccxadd, -mno-cmpccxadd

.. option:: -mcrc32, -mno-crc32

.. option:: -mcx16, -mno-cx16

.. option:: -menqcmd, -mno-enqcmd

.. option:: -mf16c, -mno-f16c

.. option:: -mfma, -mno-fma

.. option:: -mfma4, -mno-fma4

.. option:: -mfsgsbase, -mno-fsgsbase

.. option:: -mfxsr, -mno-fxsr

.. option:: -mgfni, -mno-gfni

.. option:: -mhreset, -mno-hreset

.. option:: -minvpcid, -mno-invpcid

.. option:: -mkl, -mno-kl

.. option:: -mlwp, -mno-lwp

.. option:: -mlzcnt, -mno-lzcnt

.. option:: -mmmx, -mno-mmx

.. option:: -mmovbe, -mno-movbe

.. option:: -mmovdir64b, -mno-movdir64b

.. option:: -mmovdiri, -mno-movdiri

.. option:: -mmovrs, -mno-movrs

.. option:: -mmwaitx, -mno-mwaitx

.. option:: -mpclmul, -mno-pclmul

.. option:: -mpconfig, -mno-pconfig

.. option:: -mpku, -mno-pku

.. option:: -mpopcnt, -mno-popcnt

.. option:: -mprefetchi, -mno-prefetchi

.. option:: -mprfchw, -mno-prfchw

.. option:: -mptwrite, -mno-ptwrite

.. option:: -mraoint, -mno-raoint

.. option:: -mrdpid, -mno-rdpid

.. option:: -mrdpru, -mno-rdpru

.. option:: -mrdrnd, -mno-rdrnd

.. option:: -mrdseed, -mno-rdseed

.. option:: -mretpoline-external-thunk, -mno-retpoline-external-thunk

.. option:: -mrtm, -mno-rtm

.. option:: -msahf, -mno-sahf

.. option:: -mserialize, -mno-serialize

.. option:: -msgx, -mno-sgx

.. option:: -msha, -mno-sha

.. option:: -msha512, -mno-sha512

.. option:: -mshstk, -mno-shstk

.. option:: -msm3, -mno-sm3

.. option:: -msm4, -mno-sm4

.. option:: -msse, -mno-sse

.. option:: -msse2, -mno-sse2

.. option:: -msse3, -mno-sse3

.. option:: -msse4.1, -mno-sse4.1

.. program:: clang1
.. option:: -msse4.2, -mno-sse4.2, -msse4
.. program:: clang

.. option:: -msse4a, -mno-sse4a

.. option:: -mssse3, -mno-ssse3

.. option:: -mtbm, -mno-tbm

.. option:: -mtsxldtrk, -mno-tsxldtrk

.. option:: -muintr, -mno-uintr

.. option:: -musermsr, -mno-usermsr

.. option:: -mvaes, -mno-vaes

.. option:: -mvpclmulqdq, -mno-vpclmulqdq

.. option:: -mvzeroupper, -mno-vzeroupper

.. option:: -mwaitpkg, -mno-waitpkg

.. option:: -mwbnoinvd, -mno-wbnoinvd

.. option:: -mwidekl, -mno-widekl

.. option:: -mx87, -m80387, -mno-x87

.. option:: -mxop, -mno-xop

.. option:: -mxsave, -mno-xsave

.. option:: -mxsavec, -mno-xsavec

.. option:: -mxsaveopt, -mno-xsaveopt

.. option:: -mxsaves, -mno-xsaves

RISC-V
------
.. option:: -msave-restore, -mno-save-restore

Enable using library calls for save and restore

VE
--
.. option:: -mvevpu, -mno-vevpu

Emit VPU instructions for VE

LoongArch
---------
.. option:: -mannotate-tablejump, -mno-annotate-tablejump

Enable annotate table jump instruction to correlate it with the jump table.

.. option:: -mdiv32, -mno-div32

Use div.w\[u\] and mod.w\[u\] instructions with input not sign-extended.

.. option:: -mfrecipe, -mno-frecipe

Enable frecipe.{s/d} and frsqrte.{s/d}

.. option:: -mlam-bh, -mno-lam-bh

Enable amswap\[_db\].{b/h} and amadd\[_db\].{b/h}

.. option:: -mlamcas, -mno-lamcas

Enable amcas\[_db\].{b/h/w/d}

.. option:: -mlasx, -mno-lasx

Enable Loongson Advanced SIMD Extension (LASX).

.. option:: -mld-seq-sa, -mno-ld-seq-sa

Do not generate same-address load-load barrier instructions (dbar 0x700)

.. option:: -mlsx, -mno-lsx

Enable Loongson SIMD Extension (LSX).

.. option:: -mscq, -mno-scq

Enable sc.q instruction.

.. option:: -msimd=<arg>

Select the SIMD extension(s) to be enabled in LoongArch either 'none', 'lsx', 'lasx'.

Long double options
-------------------
Selects the long double implementation

.. option:: -mlong-double-128

Force long double to be 128 bits

.. option:: -mlong-double-64

Force long double to be 64 bits

.. option:: -mlong-double-80

Force long double to be 80 bits, padded to 128 bits for storage

Sanitizer Coverage options
~~~~~~~~~~~~~~~~~~~~~~~~~~
.. option:: -fsanitize-coverage-allowlist=<arg>

Restrict sanitizer coverage instrumentation exclusively to modules and functions that match the provided special case list, except the blocked ones

.. option:: -fsanitize-coverage-ignorelist=<arg>

Disable sanitizer coverage instrumentation for modules and functions that match the provided special case list, even the allowed ones

.. option:: -fsanitize-coverage-stack-depth-callback-min=<M>

Use callback for max stack depth tracing with minimum stack depth M

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

Specify the type of coverage instrumentation for Sanitizers

Optimization level
~~~~~~~~~~~~~~~~~~

Flags controlling how much optimization should be performed.

.. option:: -O<arg>, -O (equivalent to -O1), --optimize, --optimize=<arg>

.. option:: -Ofast<arg>

Deprecated; use '-O3 -ffast-math' for the same behavior, or '-O3' to enable only conforming optimizations

Debug information generation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

Kind and level of debug information
-----------------------------------
.. option:: -g, --debug, --debug=<arg>

Generate source-level debug information

.. option:: -gcodeview

Generate CodeView debug information

.. option:: -gdwarf

Generate source-level debug information with the default DWARF version

.. option:: -gdwarf-2

Generate source-level debug information with DWARF version 2

.. option:: -gdwarf-3

Generate source-level debug information with DWARF version 3

.. option:: -gdwarf-4

Generate source-level debug information with DWARF version 4

.. option:: -gdwarf-5

Generate source-level debug information with DWARF version 5

.. option:: -gdwarf-6

Generate source-level debug information with DWARF version 6

.. option:: -gdwarf32

Enables DWARF32 format for ELF binaries, if debug information emission is enabled.

.. option:: -gdwarf64

Enables DWARF64 format for ELF binaries, if debug information emission is enabled.

.. option:: -gfull

.. option:: -gused

Debug level
___________
.. option:: -g0

.. option:: -g2

.. option:: -g3

.. option:: -ggdb0

.. option:: -ggdb1

.. option:: -ggdb2

.. option:: -ggdb3

.. option:: -gline-directives-only

Emit debug line info directives only

.. option:: -gline-tables-only, -g1, -gmlt

Emit debug line number tables only

.. option:: -gmodules, -gno-modules

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

Debugger to tune debug information for
______________________________________
.. option:: -gdbx

.. option:: -ggdb

.. option:: -glldb

.. option:: -gsce

Debug information options
-------------------------
.. option:: -gcall-site-info, -gno-call-site-info

Call site debug info enables various debugger features including detecting tail calls for display in backtraces and displaying some source variable values that reference the call entry value.

.. option:: -gcodeview-command-line, -gno-codeview-command-line

Emit compiler path and command line into CodeView debug information

.. option:: -gcodeview-ghash, -gno-codeview-ghash

Emit type record hashes in a .debug$H section

.. option:: -gcolumn-info, -gno-column-info

.. option:: -gdwarf-aranges

.. option:: -gembed-source, -gno-embed-source

Embed source text in DWARF debug sections

.. option:: -ggnu-pubnames, -gno-gnu-pubnames

.. option:: -ginline-line-tables, -gno-inline-line-tables

.. option:: -gkey-instructions, -gno-key-instructions

Enable Key Instructions, which reduces the jumpiness of debug stepping in optimized C/C++ code in some debuggers. DWARF only.

.. option:: -gomit-unreferenced-methods, -gno-omit-unreferenced-methods

.. option:: -gpubnames, -gno-pubnames

.. option:: -grecord-command-line, -gno-record-command-line, -grecord-gcc-switches

.. option:: -gsimple-template-names, -gno-simple-template-names

.. option:: -gsplit-dwarf, -gno-split-dwarf

.. program:: clang1
.. option:: -gsplit-dwarf=<arg>
.. program:: clang

Set DWARF fission mode. <arg> must be 'split' or 'single'.

.. option:: -gstrict-dwarf, -gno-strict-dwarf

Restrict DWARF features to those defined in the specified version, avoiding features from later versions.

.. option:: -gstructor-decl-linkage-names, -gno-structor-decl-linkage-names

On some ABIs (e.g., Itanium), constructors and destructors may have multiple variants. Historically, when generating DWARF, Clang did not attach ``DW_AT_linkage_name`` to structor DIEs because there were multiple possible manglings (depending on the structor variant) that could be used. With ``-gstructor-decl-linkage-names``, for ABIs with structor variants, we attach a "unified" mangled name to structor declarations DIEs which debuggers can use to look up all the definitions for a structor declaration. E.g., a "unified" mangled name ``_ZN3FooC4Ev`` may have multiple definitions associated with it such as ``_ZN3FooC1Ev`` and ``_ZN3FooC2Ev``.

Enabling this flag results in a better interactive debugging experience (both GDB and LLDB have support for understanding these "unified" linkage names). However, it comes with a significant increase in debug-info size (particularly the `.debug_str` section). As an escape hatch, users can disable this feature using ``-gno-structor-decl-linkage-names``.

.. option:: -gtemplate-alias, -gno-template-alias

.. option:: -gz=<arg>, -gz (equivalent to -gz=zlib)

DWARF debug sections compression type

Static analyzer options
=======================

Flags controlling the behavior of the Clang Static Analyzer.

.. option:: -Xanalyzer <arg>

Pass <arg> to the static analyzer

SSAF options
============

Flags controlling the behavior of the Scalable Static Analysis Framework (SSAF).

.. option:: --ssaf-compilation-unit-id=<id>

Stable identifier used as the CompilationUnit namespace name of every produced SSAF TU summary. Required when '--ssaf-tu-summary-file=' is set.

.. option:: --ssaf-extract-summaries=<summary-names>,<arg2>...

Comma-separated list of summary names to extract

.. option:: --ssaf-include-local-entities

Include block-scope (function-local) declarations in extracted SSAF summaries. By default they are omitted.

.. option:: --ssaf-list-extractors

Display the list of available SSAF summary extractors

.. option:: --ssaf-list-formats

Display the list of available SSAF serialization formats

.. option:: --ssaf-tu-summary-file=<path>.<format>

The output file for the extracted summaries. The extension selects which file format to use.

Fortran compilation options
===========================

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

.. option:: -A<arg>, --assert <arg>, --assert=<arg>

.. option:: -A-<arg>

.. option:: -faggressive-function-elimination, -fno-aggressive-function-elimination

.. option:: -falign-commons, -fno-align-commons

.. option:: -fall-intrinsics, -fno-all-intrinsics

.. option:: -fbacktrace, -fno-backtrace

.. option:: -fblas-matmul-limit=<arg>

.. option:: -fbounds-check, -fno-bounds-check

.. option:: -fcheck-array-temporaries, -fno-check-array-temporaries

.. option:: -fcheck=<arg>

.. option:: -fcray-pointer, -fno-cray-pointer

.. option:: -fdollar-ok, -fno-dollar-ok

.. option:: -fdump-fortran-optimized, -fno-dump-fortran-optimized

.. option:: -fdump-fortran-original, -fno-dump-fortran-original

.. option:: -fdump-parse-tree, -fno-dump-parse-tree

.. option:: -fexternal-blas, -fno-external-blas

.. option:: -ff2c, -fno-f2c

.. option:: -ffpe-trap=<arg>

.. option:: -ffree-line-length-<arg>

.. option:: -ffrontend-optimize, -fno-frontend-optimize

.. option:: -finit-character=<arg>

.. option:: -finit-integer=<arg>

.. option:: -finit-local-zero, -fno-init-local-zero

.. option:: -finit-logical=<arg>

.. option:: -finit-real=<arg>

.. option:: -finteger-4-integer-8, -fno-integer-4-integer-8

.. option:: -fmax-array-constructor=<arg>

.. option:: -fmax-errors=<arg>

.. option:: -fmax-identifier-length, -fno-max-identifier-length

.. option:: -fmax-stack-var-size=<arg>

.. option:: -fmax-subrecord-length=<arg>

.. option:: -fmodule-private, -fno-module-private

.. option:: -fpack-derived, -fno-pack-derived

.. option:: -frange-check, -fno-range-check

.. option:: -freal-4-real-10, -fno-real-4-real-10

.. option:: -freal-4-real-16, -fno-real-4-real-16

.. option:: -freal-4-real-8, -fno-real-4-real-8

.. option:: -freal-8-real-10, -fno-real-8-real-10

.. option:: -freal-8-real-16, -fno-real-8-real-16

.. option:: -freal-8-real-4, -fno-real-8-real-4

.. option:: -frecord-marker=<arg>

.. option:: -frecursive, -fno-recursive

.. option:: -fsecond-underscore, -fno-second-underscore

.. option:: -fsign-zero, -fno-sign-zero

.. option:: -fwhole-file, -fno-whole-file

.. option:: -imultilib <arg>

.. option:: -static-libgfortran

Linker options
==============
Flags that are passed on to the linker

.. option:: -L<dir>, --library-directory <arg>, --library-directory=<arg>

Add directory to library search path

.. option:: -Mach

.. option:: -T<script>

Specify <script> as linker script

.. option:: -Wl,<arg>,<arg2>...

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

.. option:: -X

.. option:: -Xlinker <arg>, --for-linker <arg>, --for-linker=<arg>

Pass <arg> to the linker

.. option:: -Xoffload-compiler<triple> <arg>

Pass <arg> to the offload compilers or the ones identified by -<triple>

.. option:: -Xoffload-linker<triple> <arg>

Pass <arg> to the offload linkers or the ones identified by -<triple>

.. option:: -Xthinlto-distributor=<arg>,<arg2>...

Pass <arg> to the ThinLTO distributor process. Can be specified multiple times or with comma-separated values.

.. option:: -Z

.. option:: -b<arg>

Pass -b <arg> to the linker on AIX

.. option:: -coverage, --coverage

.. option:: -e <arg>, --entry

.. option:: -filelist <arg>

.. option:: -l<arg>

.. option:: --ld-path=<arg>

.. option:: -mxcoff-build-id=<0xHEXSTRING>

On AIX, request creation of a build-id string, "0xHEXSTRING", in the string table of the loader section inside the linked binary

.. option:: -nostartfiles

.. program:: clang1
.. option:: -nostdlib, --no-standard-libraries
.. program:: clang

.. option:: --offload-link

Use the new offloading linker to perform the link job.

.. option:: -pie, -no-pie

.. option:: -r

.. option:: -rdynamic

.. option:: -rpath <arg>

.. option:: -s

.. option:: -shared, --shared

.. option:: -specs=<arg>, --specs=<arg>

.. option:: -startfiles

.. option:: -static, --static

.. option:: -static-pie

.. program:: clang2
.. option:: -stdlib
.. program:: clang

.. option:: -t

.. option:: -u<arg>, --force-link <arg>, --force-link=<arg>

.. option:: -undef

undef all system defines

.. option:: -undefined<arg>, --no-undefined

.. option:: -z <arg>

Pass -z <arg> to the linker

clang-dxc options
=================
dxc compatibility options.

.. option:: --dxv-path=<arg>

DXIL validator installation path

.. option:: -fdx-rootsignature-define=<arg>

Override entry function root signature with root signature at given macro name.

.. option:: -fdx-rootsignature-version=<arg>

Root Signature Version. <arg> must be 'rootsig_1_0', 'rootsig_1_1' or 'rootsig_1_2'.

.. option:: -fspv-extension=<arg>

Specify the available SPIR-V extensions. If this option is not specified, then all extensions are available. If KHR is specified, then all KHR extensions will be available. If DXC is specifided, then all extensions implemented by the DirectX Shader compiler will be available. This option is useful for moving from DXC to Clang.

.. option:: -fspv-target-env=<arg>

Specify the target environment. <arg> must be 'vulkan1.2' or ' vulkan1.3'.

.. option:: /hlsl-all-resources-bound, -hlsl-all-resources-bound

Enables agressive flattening

.. option:: -hlsl-entry <arg>

Entry point name for hlsl

.. option:: --spirv-val-path=<arg>

SPIRV validator installation path

