Preprocessor flags¶

Flags controlling the behavior of the Clang preprocessor.

-C, --comments¶

Include comments in preprocessed output

-CC, --comments-in-macros¶

Include comments from within macros in preprocessed output

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

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

-H, --trace-includes¶

Show header includes and nesting depth

-P, --no-line-commands¶

Disable linemarker output in -E mode

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

Undefine macro <macro>

-Wp,<arg>,<arg2>...¶

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

-Xpreprocessor <arg>¶

Pass <arg> to the preprocessor

Diagnostic flags¶

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

-R<remark>¶

Enable the specified remark

-Rpass-analysis=<arg>¶

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

-Rpass-missed=<arg>¶

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

-Rpass=<arg>¶

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

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

Enable the specified warning

-Wdeprecated, -Wno-deprecated¶

Enable warnings for deprecated constructs and define __DEPRECATED

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

Target-independent compilation options¶

-Wframe-larger-than=<arg>¶

-fPIC, -fno-PIC¶

-fPIE, -fno-PIE¶

-faccess-control, -fno-access-control¶

-faddrsig, -fno-addrsig¶

Emit an address-significance table

-falign-functions, -fno-align-functions¶

-falign-functions=<arg>¶

-faligned-allocation, -faligned-new, -fno-aligned-allocation¶

Enable C++17 aligned allocation functions

-fallow-editor-placeholders, -fno-allow-editor-placeholders¶

Treat editor placeholders as valid source code

-fallow-unsupported¶

-faltivec, -fno-altivec¶

-fansi-escape-codes¶

Use ANSI escape codes for diagnostics

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

Use Apple’s kernel extensions ABI

-fapple-link-rtlib¶

Force linking the clang builtins runtime library

-fapple-pragma-pack, -fno-apple-pragma-pack¶

Enable Apple gcc-compatible #pragma pack handling

-fapplication-extension, -fno-application-extension¶

Restrict code to those available for App Extensions

-fasm, -fno-asm¶

-fasm-blocks, -fno-asm-blocks¶

-fassociative-math, -fno-associative-math¶

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

-fast¶

-fastcp¶

-fastf¶

-fasynchronous-unwind-tables, -fno-asynchronous-unwind-tables¶

-fautolink, -fno-autolink¶

-fblocks, -fno-blocks¶

Enable the ‘blocks’ language feature

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

-fborland-extensions, -fno-borland-extensions¶

Accept non-standard constructs supported by the Borland compiler

-fbracket-depth=<arg>¶

-fbuiltin, -fno-builtin¶

-fbuiltin-module-map¶

Load the clang builtins module map file.

-fc++-static-destructors, -fno-c++-static-destructors¶

Enable C++ static destructor registration (the default)

-fcaret-diagnostics, -fno-caret-diagnostics¶

-fcf-protection=<arg>, -fcf-protection (equivalent to -fcf-protection=full)¶

Instrument control-flow architecture protection. Options: return, branch, full, none.

-fcf-runtime-abi=<arg>¶

-fchar8_t, -fno-char8_t¶

Enable C++ builtin type char8_t

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

-fcolor-diagnostics, -fno-color-diagnostics¶

Use colors in diagnostics

-fcommon, -fno-common¶

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

-fconstant-cfstrings, -fno-constant-cfstrings¶

-fconstant-string-class=<arg>¶

-fconstexpr-backtrace-limit=<arg>¶

-fconstexpr-depth=<arg>¶

-fconstexpr-steps=<arg>¶

-fcoroutines-ts, -fno-coroutines-ts¶

Enable support for the C++ Coroutines TS

-fcoverage-mapping, -fno-coverage-mapping¶

Generate coverage mapping to enable code coverage analysis

-fcreate-profile¶

-fcs-profile-generate¶

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

-fcs-profile-generate=<directory>¶

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

-fcxx-exceptions, -fno-cxx-exceptions¶

Enable C++ exceptions

-fcxx-modules, -fno-cxx-modules¶

-fdata-sections, -fno-data-sections¶

Place each data in its own section (ELF Only)

-fdebug-compilation-dir <arg>¶

The compilation directory to embed in the debug info.

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

Emit extra debug info to make sample profile more accurate.

-fdebug-macro, -fno-debug-macro¶

Emit macro debug information

-fdebug-pass-arguments¶

-fdebug-pass-structure¶

-fdebug-prefix-map=<arg>¶

remap file source paths in debug info

-fdebug-ranges-base-address, -fno-debug-ranges-base-address¶

Use DWARF base address selection entries in debug_ranges

-fdebug-types-section, -fno-debug-types-section¶

Place debug types in their own section (ELF Only)

-fdelayed-template-parsing, -fno-delayed-template-parsing¶

Parse templated function definitions at the end of the translation unit

-fdelete-null-pointer-checks, -fno-delete-null-pointer-checks¶

Treat usage of null pointers as undefined behavior.

-fdenormal-fp-math=<arg>¶

-fdiagnostics-absolute-paths¶

Print absolute paths in diagnostics

-fdiagnostics-color, -fno-diagnostics-color¶

-fdiagnostics-color=<arg>¶

-fdiagnostics-hotness-threshold=<number>¶

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

-fdiagnostics-show-hotness, -fno-diagnostics-show-hotness¶

Enable profile hotness information in diagnostic line

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

Display include stacks for diagnostic notes

-fdiagnostics-show-option, -fno-diagnostics-show-option¶

Print option name with mappable diagnostics

-fdiagnostics-show-template-tree¶

Print a template comparison tree for differing templates

-fdigraphs, -fno-digraphs¶

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

-fdollars-in-identifiers, -fno-dollars-in-identifiers¶

Allow ‘$’ in identifiers

-fdouble-square-bracket-attributes, -fno-double-square-bracket-attributes¶

Enable ‘[[]]’ attributes in all C and C++ language modes

-fdwarf-directory-asm, -fno-dwarf-directory-asm¶

-fdwarf-exceptions¶

Use DWARF style exceptions

-felide-constructors, -fno-elide-constructors¶

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

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

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

-femit-all-decls¶

Emit all declarations, even if unused

-femulated-tls, -fno-emulated-tls¶

Use emutls functions to access thread_local variables

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

-ferror-limit=<arg>¶

-fescaping-block-tail-calls, -fno-escaping-block-tail-calls¶

-fexceptions, -fno-exceptions¶

Enable support for exception handling

-fexec-charset=<arg>¶

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

-ffast-math, -fno-fast-math¶

Allow aggressive, lossy floating-point optimizations

-ffinite-math-only, -fno-finite-math-only¶

-ffixed-point, -fno-fixed-point¶

Enable fixed point types

-ffor-scope, -fno-for-scope¶

-fforce-emit-vtables, -fno-force-emit-vtables¶

Emits more virtual tables to improve devirtualization

-fforce-enable-int128, -fno-force-enable-int128¶

Enable support for int128_t type

-ffp-contract=<arg>¶

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

-ffreestanding¶

Assert that the compilation takes place in a freestanding environment

-ffunction-sections, -fno-function-sections¶

Place each function in its own section (ELF Only)

-fgnu-inline-asm, -fno-gnu-inline-asm¶

-fgnu-keywords, -fno-gnu-keywords¶

Allow GNU-extension keywords regardless of language standard

-fgnu-runtime¶

Generate output compatible with the standard GNU Objective-C runtime

-fgnu89-inline, -fno-gnu89-inline¶

Use the gnu89 inline semantics

-fhonor-infinities, -fhonor-infinites, -fno-honor-infinities¶

-fhonor-nans, -fno-honor-nans¶

-fhosted¶

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

Implicitly search the file system for module map files.

-fimplicit-modules, -fno-implicit-modules¶

-finput-charset=<arg>¶

-finstrument-function-entry-bare¶

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

-finstrument-functions¶

Generate calls to instrument function entry and exit

-finstrument-functions-after-inlining¶

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

-fintegrated-as, -fno-integrated-as, -integrated-as¶

Enable the integrated assembler

-fjump-tables, -fno-jump-tables¶

-fkeep-static-consts¶

Keep static const variables even if unused

-flax-vector-conversions, -fno-lax-vector-conversions¶

-flimited-precision=<arg>¶

-flto, -fno-lto¶

Enable LTO in ‘full’ mode

-flto-jobs=<arg>¶

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

-flto=<arg>¶

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

-fmacro-backtrace-limit=<arg>¶

-fmath-errno, -fno-math-errno¶

Require math functions to indicate errors by setting errno

-fmax-type-align=<arg>¶

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

-fmerge-all-constants, -fno-merge-all-constants¶

Allow merging of constants

-fmessage-length=<arg>¶

-fmodule-file-deps, -fno-module-file-deps¶

-fmodule-map-file=<file>¶

Load this module map file

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

Specify the name of the module to build

-fmodules, -fno-modules¶

Enable the ‘modules’ language feature

-fmodules-decluse, -fno-modules-decluse¶

Require declaration of modules used within a module

-fmodules-ignore-macro=<arg>¶

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

-fmodules-search-all, -fno-modules-search-all¶

Search even non-imported modules to resolve references

-fmodules-strict-decluse¶

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

-fmodules-ts¶

Enable support for the C++ Modules TS

-fms-compatibility, -fno-ms-compatibility¶

Enable full Microsoft Visual C++ compatibility

-fms-compatibility-version=<arg>¶

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

-fms-extensions, -fno-ms-extensions¶

Accept some non-standard constructs supported by the Microsoft compiler

-fms-memptr-rep=<arg>¶

-fms-volatile<arg>¶

-fmsc-version=<arg>¶

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

-fmudflap¶

-fmudflapth¶

-fnested-functions¶

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

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

-fnext-runtime¶

-fno-builtin-<arg>¶

Disable implicit builtin knowledge of a specific function

-fno-elide-type¶

Do not elide types when printing diagnostics

-fno-max-type-align¶

-fno-operator-names¶

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

-fno-rtti-data¶

Control emission of RTTI data

-fno-strict-modules-decluse¶

-fno-working-directory¶

-fnoxray-link-deps¶

-fobjc-abi-version=<arg>¶

-fobjc-arc, -fno-objc-arc¶

Synthesize retain and release calls for Objective-C pointers

-fobjc-arc-exceptions, -fno-objc-arc-exceptions¶

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

-fobjc-convert-messages-to-runtime-calls, -fno-objc-convert-messages-to-runtime-calls¶

-fobjc-exceptions, -fno-objc-exceptions¶

Enable Objective-C exceptions

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

-fobjc-legacy-dispatch, -fno-objc-legacy-dispatch¶

-fobjc-link-runtime¶

-fobjc-nonfragile-abi, -fno-objc-nonfragile-abi¶

-fobjc-nonfragile-abi-version=<arg>¶

-fobjc-runtime=<arg>¶

Specify the target Objective-C runtime kind and version

-fobjc-sender-dependent-dispatch¶

-fobjc-weak, -fno-objc-weak¶

Enable ARC-style weak references in Objective-C

-fomit-frame-pointer, -fno-omit-frame-pointer¶

-fopenmp, -fno-openmp¶

Parse OpenMP pragmas and generate parallel code.

-fopenmp-simd, -fno-openmp-simd¶

Emit OpenMP code only for SIMD-based constructs.

-fopenmp-version=<arg>¶

-fopenmp=<arg>¶

-foperator-arrow-depth=<arg>¶

-foptimization-record-file=<arg>¶

Specify the file name of any generated YAML optimization record

-foptimization-record-passes=<arg>¶

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

-foptimize-sibling-calls, -fno-optimize-sibling-calls¶

-forder-file-instrumentation¶

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

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

-fpack-struct, -fno-pack-struct¶

-fpack-struct=<arg>¶

Specify the default maximum struct packing alignment

-fpascal-strings, -fno-pascal-strings, -mpascal-strings¶

Recognize and construct Pascal-style string literals

-fpass-plugin=<dsopath>¶

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

-fpcc-struct-return¶

Override the default ABI to return all structs on the stack

-fpch-preprocess¶

-fpic, -fno-pic¶

-fpie, -fno-pie¶

-fplt, -fno-plt¶

Use the PLT to make function calls

-fplugin=<dsopath>¶

Load the named plugin (dynamic shared object)

-fpreserve-as-comments, -fno-preserve-as-comments¶

-fprofile-arcs, -fno-profile-arcs¶

-fprofile-dir=<arg>¶

-fprofile-exclude-files=<arg>¶

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

-fprofile-filter-files=<arg>¶

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

-fprofile-generate, -fno-profile-generate¶

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

-fprofile-generate=<directory>¶

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

-fprofile-instr-generate, -fno-profile-instr-generate¶

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

-fprofile-instr-generate=<file>¶

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

-fprofile-instr-use, -fno-profile-instr-use, -fprofile-use¶

-fprofile-instr-use=<arg>¶

Use instrumentation data for profile-guided optimization

-fprofile-remapping-file=<file>, -fprofile-remapping-file <arg>¶

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

-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

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

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

Enable sample-based profile guided optimizations

-fprofile-use=<pathname>¶

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

-freciprocal-math, -fno-reciprocal-math¶

Allow division operations to be reassociated

-freg-struct-return¶

Override the default ABI to return small structs in registers

-fregister-global-dtors-with-atexit, -fno-register-global-dtors-with-atexit¶

Use atexit or __cxa_atexit to register global destructors

-frelaxed-template-template-args, -fno-relaxed-template-template-args¶

Enable C++17 relaxed template template argument matching

-freroll-loops, -fno-reroll-loops¶

Turn on loop reroller

-fretain-comments-from-system-headers¶

-frewrite-imports, -fno-rewrite-imports¶

-frewrite-includes, -fno-rewrite-includes¶

-frewrite-map-file <arg>¶

-frewrite-map-file=<arg>¶

-fropi, -fno-ropi¶

-frtti, -fno-rtti¶

-frwpi, -fno-rwpi¶

-fsave-optimization-record, -fno-save-optimization-record¶

Generate a YAML optimization record file

-fsave-optimization-record=<arg>¶

Generate an optimization record file in a specific format (default: YAML)

-fseh-exceptions¶

Use SEH style exceptions

-fshort-enums, -fno-short-enums¶

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

-fshort-wchar, -fno-short-wchar¶

Force wchar_t to be a short unsigned int

-fshow-column, -fno-show-column¶

-fshow-overloads=<arg>¶

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

-fshow-source-location, -fno-show-source-location¶

-fsignaling-math, -fno-signaling-math¶

-fsigned-bitfields¶

-fsigned-char, -fno-signed-char, --signed-char¶

-fsigned-zeros, -fno-signed-zeros¶

-fsized-deallocation, -fno-sized-deallocation¶

Enable C++14 sized global deallocation functions

-fsjlj-exceptions¶

Use SjLj style exceptions

-fslp-vectorize, -fno-slp-vectorize, -ftree-slp-vectorize¶

Enable the superword-level parallelism vectorization passes

-fspell-checking, -fno-spell-checking¶

-fspell-checking-limit=<arg>¶

-fsplit-dwarf-inlining, -fno-split-dwarf-inlining¶

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

-fsplit-lto-unit, -fno-split-lto-unit¶

Enables splitting of the LTO unit.

-fsplit-stack¶

-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

-fstack-protector-all¶

Enable stack protectors for all functions

-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

-fstack-size-section, -fno-stack-size-section¶

Emit section containing metadata on function stack sizes

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

Emit full debug info for all types used by the program

-fstrict-aliasing, -fno-strict-aliasing¶

-fstrict-enums, -fno-strict-enums¶

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

-fstrict-float-cast-overflow, -fno-strict-float-cast-overflow¶

Assume that overflowing float-to-int casts are undefined (default)

-fstrict-overflow, -fno-strict-overflow¶

-fstrict-return, -fno-strict-return¶

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

-fstrict-vtable-pointers, -fno-strict-vtable-pointers¶

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

-fstruct-path-tbaa, -fno-struct-path-tbaa¶

-fsymbol-partition=<arg>¶

-ftabstop=<arg>¶

-ftemplate-backtrace-limit=<arg>¶

-ftemplate-depth-<arg>¶

-ftemplate-depth=<arg>¶

-ftest-coverage¶

-fthinlto-index=<arg>¶

Perform ThinLTO importing using provided function summary index

-fthreadsafe-statics, -fno-threadsafe-statics¶

-ftime-report¶

-ftime-trace¶

-ftls-model=<arg>¶

-ftrap-function=<arg>¶

Issue call to specified function rather than a trap instruction

-ftrapping-math, -fno-trapping-math¶

-ftrapv¶

Trap on integer overflow

-ftrapv-handler <arg>¶

-ftrapv-handler=<function name>¶

Specify the function to be called on overflow

-ftrigraphs, -fno-trigraphs, -trigraphs, --trigraphs¶

Process trigraph sequences

-ftrivial-auto-var-init=<arg>¶

Initialize trivial automatic stack variables: uninitialized (default) | pattern

-funique-section-names, -fno-unique-section-names¶

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

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

-funroll-loops, -fno-unroll-loops¶

Turn on loop unroller

-funsafe-math-optimizations, -fno-unsafe-math-optimizations¶

-funsigned-bitfields¶

-funsigned-char, -fno-unsigned-char, --unsigned-char¶

-funwind-tables, -fno-unwind-tables¶

-fuse-cxa-atexit, -fno-use-cxa-atexit¶

-fuse-init-array, -fno-use-init-array¶

Use .init_array instead of .ctors

-fuse-ld=<arg>¶

-fuse-line-directives, -fno-use-line-directives¶

-fveclib=<arg>¶

Use the given vector functions library

-fvectorize, -fno-vectorize, -ftree-vectorize¶

Enable the loop vectorization passes

-fverbose-asm, -fno-verbose-asm¶

-fvisibility-global-new-delete-hidden¶

Give global C++ operator new and delete declarations hidden visibility

-fvisibility-inlines-hidden¶

Give inline C++ member functions hidden visibility by default

-fvisibility-ms-compat¶

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

-fvisibility=<arg>¶

Set the default symbol visibility for all global declarations

-fwhole-program-vtables, -fno-whole-program-vtables¶

Enables whole-program vtable optimization. Requires -flto

-fwrapv, -fno-wrapv¶

Treat signed integer overflow as two’s complement

-fwritable-strings¶

Store string literals as writable data

-fxray-always-emit-customevents, -fno-xray-always-emit-customevents¶

Determine whether to always emit __xray_customevent(…) calls even if the function it appears in is not always instrumented.

-fxray-always-emit-typedevents, -fno-xray-always-emit-typedevents¶

Determine whether to always emit __xray_typedevent(…) calls even if the function it appears in is not always instrumented.

-fxray-always-instrument=<arg>¶

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

-fxray-attr-list=<arg>¶

Filename defining the list of functions/types for imbuing XRay attributes.

-fxray-instruction-threshold<arg>¶

-fxray-instruction-threshold=<arg>¶

Sets the minimum function size to instrument with XRay

-fxray-instrument, -fno-xray-instrument¶

Generate XRay instrumentation sleds on function entry and exit

-fxray-instrumentation-bundle=<arg>¶

Select which XRay instrumentation points to emit. Options: all, none, function, custom. Default is ‘all’.

-fxray-link-deps¶

Tells clang to add the link dependencies for XRay.

-fxray-modes=<arg>¶

List of modes to link in by default into XRay instrumented binaries.

-fxray-never-instrument=<arg>¶

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

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

-fzvector, -fno-zvector, -mzvector¶

Enable System z vector language extension

-mlong-double-128¶

Force long double to be 128 bits

-mlong-double-64¶

Force long double to be 64 bits

-pedantic, --pedantic, -no-pedantic, --no-pedantic¶

-pedantic-errors, --pedantic-errors¶

Target-dependent compilation options¶

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

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

-m16¶

-m32¶

-m64¶

-mabi=<arg>¶

-malign-double¶

Align doubles to two words in structs (x86 only)

-march=<arg>¶

-masm=<arg>¶

-mbackchain, -mno-backchain¶

Link stack frames through backchain on System Z

-mcmodel=<arg>¶

-mconsole<arg>¶

-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)¶

-mcrc, -mno-crc¶

Allow use of CRC instructions (ARM/Mips only)

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

-mdll<arg>¶

-mdynamic-no-pic<arg>¶

-meabi <arg>¶

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

-mfentry¶

Insert calls to fentry at function entry (x86 only)

-mfloat-abi=<arg>¶

-mfpmath=<arg>¶

-mfpu=<arg>¶

-mglobal-merge, -mno-global-merge¶

Enable merging of globals

-mhard-float¶

-mhwdiv=<arg>, --mhwdiv <arg>, --mhwdiv=<arg>¶

-mhwmult=<arg>¶

-miamcu, -mno-iamcu¶

Use Intel MCU ABI

-mimplicit-float, -mno-implicit-float¶

-mimplicit-it=<arg>¶

-mincremental-linker-compatible, -mno-incremental-linker-compatible¶

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

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

-mkernel¶

-mlong-calls, -mno-long-calls¶

Generate branches with extended addressability, usually via indirect jumps.

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

Set Mac OS X deployment target

-mmcu=<arg>¶

-mms-bitfields, -mno-ms-bitfields¶

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

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

Omit frame pointer setup for leaf functions

-moslib=<arg>¶

-mpie-copy-relocations, -mno-pie-copy-relocations¶

Use copy relocations support for PIE builds

-mprefer-vector-width=<arg>¶

Specifies preferred vector width for auto-vectorization. Defaults to ‘none’ which allows target specific decisions.

-mqdsp6-compat¶

Enable hexagon-qdsp6 backward compatibility

-mrecip¶

-mrecip=<arg1>,<arg2>...¶

-mred-zone, -mno-red-zone¶

-mregparm=<arg>¶

-mrelax-all, -mno-relax-all¶

(integrated-as) Relax all machine instructions

-mretpoline, -mno-retpoline¶

-mrtd, -mno-rtd¶

Make StdCall calling convention the default

-msign-return-address=<arg>¶

Select return address signing scope

-msoft-float, -mno-soft-float¶

Use software floating point

-mspeculative-load-hardening, -mno-speculative-load-hardening¶

-mstack-alignment=<arg>¶

Set the stack alignment

-mstack-arg-probe, -mno-stack-arg-probe¶

Enable stack probes

-mstack-probe-size=<arg>¶

Set the stack probe size

-mstackrealign, -mno-stackrealign¶

Force realign the stack at entry to every function

-mthread-model <arg>¶

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

-mthreads<arg>¶

-mthumb, -mno-thumb¶

-mtls-direct-seg-refs, -mno-tls-direct-seg-refs¶

Enable direct TLS access through segment registers (default)

-mtune=<arg>¶

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

-municode<arg>¶

-mvx, -mno-vx¶

-mwarn-nonportable-cfstrings, -mno-warn-nonportable-cfstrings¶

-mwatchos-version-min=<arg>¶

-mwavefrontsize64, -mno-wavefrontsize64¶

Wavefront size 64 is used

-mwindows<arg>¶

-mx32¶

Optimization level¶

Flags controlling how much optimization should be performed.

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

-Ofast<arg>¶

Debug information generation¶

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