path: root/gcc/config/arm/arm.opt

; Options for the ARM port of the compiler.

; Copyright (C) 2005-2024 Free Software Foundation, Inc.
;
; This file is part of GCC.
;
; GCC is free software; you can redistribute it and/or modify it under
; the terms of the GNU General Public License as published by the Free
; Software Foundation; either version 3, or (at your option) any later
; version.
;
; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
; WARRANTY; without even the implied warranty of MERCHANTABILITY or
; FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
; for more details.
;
; You should have received a copy of the GNU General Public License
; along with GCC; see the file COPYING3.  If not see
; <http://www.gnu.org/licenses/>.

HeaderInclude
config/arm/arm-opts.h

HeaderInclude
config/arm/aarch-common.h

TargetVariable
enum aarch_function_type aarch_ra_sign_scope = AARCH_FUNCTION_NONE

TargetVariable
unsigned aarch_enable_bti = 0

Enum
Name(tls_type) Type(enum arm_tls_type)
TLS dialect to use:

EnumValue
Enum(tls_type) String(gnu) Value(TLS_GNU)

EnumValue
Enum(tls_type) String(gnu2) Value(TLS_GNU2)

mabi=
Target RejectNegative Joined Enum(arm_abi_type) Var(arm_abi) Init(ARM_DEFAULT_ABI)
Specify an ABI.

Enum
Name(arm_abi_type) Type(enum arm_abi_type)
Known ARM ABIs (for use with the -mabi= option):

EnumValue
Enum(arm_abi_type) String(apcs-gnu) Value(ARM_ABI_APCS)

EnumValue
Enum(arm_abi_type) String(atpcs) Value(ARM_ABI_ATPCS)

EnumValue
Enum(arm_abi_type) String(aapcs) Value(ARM_ABI_AAPCS)

EnumValue
Enum(arm_abi_type) String(iwmmxt) Value(ARM_ABI_IWMMXT)

EnumValue
Enum(arm_abi_type) String(aapcs-linux) Value(ARM_ABI_AAPCS_LINUX)

mabort-on-noreturn
Target Mask(ABORT_NORETURN)
Generate a call to abort if a noreturn function returns.

mapcs
Target RejectNegative Mask(APCS_FRAME) Undocumented

mapcs-frame
Target Mask(APCS_FRAME)
Generate APCS conformant stack frames.

mapcs-reentrant
Target Mask(APCS_REENT)
Generate re-entrant, PIC code.

mapcs-stack-check
Target Mask(APCS_STACK) Undocumented

march=
Target Save RejectNegative Negative(march=) ToLower Joined Var(arm_arch_string)
Specify the name of the target architecture.

; Other arm_arch values are loaded from arm-tables.opt
; but that is a generated file and this is an odd-one-out.
EnumValue
Enum(arm_arch) String(native) Value(-1) DriverOnly

; Set to the name of target architecture which is required for
; multilib linking.  This option is undocumented because it
; should not be used by the users.
mlibarch=
Target RejectNegative JoinedOrMissing NoDWARFRecord DriverOnly Undocumented

marm
Target RejectNegative Negative(mthumb) InverseMask(THUMB)
Generate code in 32 bit ARM state.

mbig-endian
Target RejectNegative Negative(mlittle-endian) Mask(BIG_END)
Assume target CPU is configured as big endian.

mcallee-super-interworking
Target Mask(CALLEE_INTERWORKING)
Thumb: Assume non-static functions may be called from ARM code.

mcaller-super-interworking
Target Mask(CALLER_INTERWORKING)
Thumb: Assume function pointers may go to non-Thumb aware code.

mcpu=
Target Save RejectNegative Negative(mcpu=) ToLower Joined Var(arm_cpu_string)
Specify the name of the target CPU.

mfloat-abi=
Target RejectNegative Joined Enum(float_abi_type) Var(arm_float_abi) Init(TARGET_DEFAULT_FLOAT_ABI)
Specify if floating point hardware should be used.

mcmse
Target RejectNegative Var(use_cmse)
Specify that the compiler should target secure code as per ARMv8-M Security Extensions.

Enum
Name(float_abi_type) Type(enum float_abi_type)
Known floating-point ABIs (for use with the -mfloat-abi= option):

EnumValue
Enum(float_abi_type) String(soft) Value(ARM_FLOAT_ABI_SOFT)

EnumValue
Enum(float_abi_type) String(softfp) Value(ARM_FLOAT_ABI_SOFTFP)

EnumValue
Enum(float_abi_type) String(hard) Value(ARM_FLOAT_ABI_HARD)

mflip-thumb
Target Var(TARGET_FLIP_THUMB) Undocumented
Switch ARM/Thumb modes on alternating functions for compiler testing.

mfp16-format=
Target RejectNegative Joined Enum(arm_fp16_format_type) Var(arm_fp16_format) Init(ARM_FP16_FORMAT_NONE)
Specify the __fp16 floating-point format.

Enum
Name(arm_fp16_format_type) Type(enum arm_fp16_format_type)
Known __fp16 formats (for use with the -mfp16-format= option):

EnumValue
Enum(arm_fp16_format_type) String(none) Value(ARM_FP16_FORMAT_NONE)

EnumValue
Enum(arm_fp16_format_type) String(ieee) Value(ARM_FP16_FORMAT_IEEE)

EnumValue
Enum(arm_fp16_format_type) String(alternative) Value(ARM_FP16_FORMAT_ALTERNATIVE)

mfpu=
Target RejectNegative Joined Enum(arm_fpu) Var(arm_fpu_index) Init(TARGET_FPU_auto) Save
Specify the name of the target floating point hardware/format.

mhard-float
Target RejectNegative Alias(mfloat-abi=, hard) Undocumented

mlittle-endian
Target RejectNegative Negative(mbig-endian) InverseMask(BIG_END)
Assume target CPU is configured as little endian.

mlong-calls
Target Mask(LONG_CALLS)
Generate call insns as indirect calls, if necessary.

mpic-data-is-text-relative
Target Var(arm_pic_data_is_text_relative) Init(TARGET_DEFAULT_PIC_DATA_IS_TEXT_RELATIVE)
Assume data segments are relative to text segment.

mpic-register=
Target RejectNegative Joined Var(arm_pic_register_string)
Specify the register to be used for PIC addressing.

mpoke-function-name
Target Mask(POKE_FUNCTION_NAME)
Store function names in object code.

msched-prolog
Target Mask(SCHED_PROLOG)
Permit scheduling of a function's prologue sequence.

msingle-pic-base
Target Mask(SINGLE_PIC_BASE)
Do not load the PIC register in function prologues.

msoft-float
Target RejectNegative Alias(mfloat-abi=, soft) Undocumented

mstructure-size-boundary=
Target RejectNegative Joined UInteger Var(arm_structure_size_boundary) Init(DEFAULT_STRUCTURE_SIZE_BOUNDARY)
Specify the minimum bit alignment of structures. (Deprecated).

mthumb
Target RejectNegative Negative(marm) Mask(THUMB) Save
Generate code for Thumb state.

mthumb-interwork
Target Mask(INTERWORK)
Support calls between Thumb and ARM instruction sets.

mtls-dialect=
Target RejectNegative Joined Enum(tls_type) Var(target_tls_dialect) Init(TLS_GNU)
Specify thread local storage scheme.

mtp=
Target RejectNegative Joined Enum(arm_tp_type) Var(target_thread_pointer) Init(TP_AUTO)
Specify how to access the thread pointer.

Enum
Name(arm_tp_type) Type(enum arm_tp_type)
Valid arguments to -mtp=:

EnumValue
Enum(arm_tp_type) String(soft) Value(TP_SOFT)

EnumValue
Enum(arm_tp_type) String(auto) Value(TP_AUTO)

EnumValue
Enum(arm_tp_type) String(tpidrurw) Value(TP_TPIDRURW)

EnumValue
Enum(arm_tp_type) String(cp15) Value(TP_TPIDRURO)

EnumValue
Enum(arm_tp_type) String(tpidruro) Value(TP_TPIDRURO)

EnumValue
Enum(arm_tp_type) String(tpidrprw) Value(TP_TPIDRPRW)

mtpcs-frame
Target Mask(TPCS_FRAME)
Thumb: Generate (non-leaf) stack frames even if not needed.

mtpcs-leaf-frame
Target Mask(TPCS_LEAF_FRAME)
Thumb: Generate (leaf) stack frames even if not needed.

mtune=
Target Save RejectNegative Negative(mtune=) ToLower Joined Var(arm_tune_string)
Tune code for the given processor.

mprint-tune-info
Target RejectNegative Var(print_tune_info) Init(0)
Print CPU tuning information as comment in assembler file.  This is
an option used only for regression testing of the compiler and not
intended for ordinary use in compiling code.

; Other processor_type values are loaded from arm-tables.opt
; but that is a generated file and this is an odd-one-out.
EnumValue
Enum(processor_type) String(native) Value(-1) DriverOnly

mvectorize-with-neon-quad
Target RejectNegative InverseMask(NEON_VECTORIZE_DOUBLE)
Use Neon quad-word (rather than double-word) registers for vectorization.

mvectorize-with-neon-double
Target RejectNegative Mask(NEON_VECTORIZE_DOUBLE)
Use Neon double-word (rather than quad-word) registers for vectorization.

mverbose-cost-dump
Common Undocumented Var(arm_verbose_cost) Init(0)
Enable more verbose RTX cost dumps during debug.  For GCC developers use only.

mword-relocations
Target Var(target_word_relocations) Init(TARGET_DEFAULT_WORD_RELOCATIONS)
Only generate absolute relocations on word sized values.

mrestrict-it
Target Var(arm_restrict_it) Init(2) Save
Generate IT blocks appropriate for ARMv8.

mfix-cortex-m3-ldrd
Target Var(fix_cm3_ldrd) Init(2)
Avoid overlapping destination and address registers on LDRD instructions
that may trigger Cortex-M3 errata.

mfix-cmse-cve-2021-35465
Target Var(fix_vlldm) Init(2)
Mitigate issues with VLLDM on some M-profile devices (CVE-2021-35465).

mfix-cortex-a57-aes-1742098
Target Var(fix_aes_erratum_1742098) Init(2) Save
Mitigate issues with AES instructions on Cortex-A57 and Cortex-A72
(Arm erratum #1742098).

mfix-cortex-a72-aes-1655431
Target Alias(mfix-cortex-a57-aes-1742098)
Mitigate issues with AES instructions on Cortex-A57 and Cortex-A72
(Arm erratum #1655431).

munaligned-access
Target Var(unaligned_access) Init(2) Save
Enable unaligned word and halfword accesses to packed data.

mneon-for-64bits
Target WarnRemoved
This option is deprecated and has no effect.

mslow-flash-data
Target Var(target_slow_flash_data) Init(0)
Assume loading data from flash is slower than fetching instructions.

masm-syntax-unified
Target Var(inline_asm_unified) Init(0) Save
Assume unified syntax for inline assembly code.

mpure-code
Target Var(target_pure_code) Init(0)
Do not allow constant data to be placed in code sections.

mbe8
Target RejectNegative Negative(mbe32) Mask(BE8)
When linking for big-endian targets, generate a BE8 format image.

mbe32
Target RejectNegative Negative(mbe8) InverseMask(BE8)
When linking for big-endian targets, generate a legacy BE32 format image.

mbranch-cost=
Target RejectNegative Joined UInteger Var(arm_branch_cost) Init(-1)
Cost to assume for a branch insn.

mbranch-protection=
Target RejectNegative Joined Var(arm_branch_protection_string) Save
Use branch-protection features.

mgeneral-regs-only
Target RejectNegative Mask(GENERAL_REGS_ONLY) Save
Generate code which uses the core registers only (r0-r14).

mfdpic
Target Mask(FDPIC)
Enable Function Descriptor PIC mode.

mstack-protector-guard=
Target RejectNegative Joined Enum(stack_protector_guard) Var(arm_stack_protector_guard) Init(SSP_GLOBAL)
Use given stack-protector guard.

Enum
Name(stack_protector_guard) Type(enum stack_protector_guard)
Valid arguments to -mstack-protector-guard=:

EnumValue
Enum(stack_protector_guard) String(tls) Value(SSP_TLSREG)

EnumValue
Enum(stack_protector_guard) String(global) Value(SSP_GLOBAL)

mstack-protector-guard-offset=
Target Joined RejectNegative String Var(arm_stack_protector_guard_offset_str)
Use an immediate to offset from the TLS register. This option is for use with
fstack-protector-guard=tls and not for use in user-land code.

mdlstp
Target Var(dlstp_enabled) Init(1) Undocumented

TargetVariable
long arm_stack_protector_guard_offset = 0