//===--- AArch64.cpp - AArch64 (not ARM) Helpers for Tools ------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#include "AArch64.h"

#include "../CommonArgs.h"

#include "clang/Driver/Driver.h"

#include "clang/Driver/DriverDiagnostic.h"

#include "clang/Driver/Options.h"

#include "llvm/Option/ArgList.h"

#include "llvm/TargetParser/AArch64TargetParser.h"

#include "llvm/TargetParser/Host.h"

using namespace clang::driver;

using namespace clang::driver::tools;

using namespace clang;

using namespace llvm::opt;

/// \returns true if the given triple can determine the default CPU type even

/// if -arch is not specified.

static bool isCPUDeterminedByTriple(const llvm::Triple &Triple) {

  return Triple.isOSDarwin();

}

/// getAArch64TargetCPU - Get the (LLVM) name of the AArch64 cpu we are

/// targeting. Set \p A to the Arg corresponding to the -mcpu argument if it is

/// provided, or to nullptr otherwise.

std::string aarch64::getAArch64TargetCPU(const ArgList &Args,

                                         const llvm::Triple &Triple, Arg *&A) {

  std::string CPU;

  // If we have -mcpu, use that.

  if ((A = Args.getLastArg(options::OPT_mcpu_EQ))) {

    StringRef Mcpu = A->getValue();

    CPU = Mcpu.split("+").first.lower();

  }

  CPU = llvm::AArch64::resolveCPUAlias(CPU);

  // Handle CPU name is 'native'.

  if (CPU == "native")

    return std::string(llvm::sys::getHostCPUName());

  if (CPU.size())

    return CPU;

  if (Triple.isTargetMachineMac() &&

      Triple.getArch() == llvm::Triple::aarch64) {

    // Apple Silicon macs default to M1 CPUs.

    return "apple-m1";

  }

  // arm64e requires v8.3a and only runs on apple-a12 and later CPUs.

  if (Triple.isArm64e())

    return "apple-a12";

  // Make sure we pick the appropriate Apple CPU when targetting a Darwin OS.

  if (Triple.isOSDarwin())

    return Triple.getArch() == llvm::Triple::aarch64_32 ? "apple-s4"

                                                        : "apple-a7";

  return "generic";

}

// Decode AArch64 features from string like +[no]featureA+[no]featureB+...

static bool DecodeAArch64Features(const Driver &D, StringRef text,

                                  std::vector<StringRef> &Features,

                                  const llvm::AArch64::ArchInfo &ArchInfo) {

  SmallVector<StringRef, 8> Split;

  text.split(Split, StringRef("+"), -1, false);

  for (StringRef Feature : Split) {

    StringRef FeatureName = llvm::AArch64::getArchExtFeature(Feature);

    if (!FeatureName.empty())

      Features.push_back(FeatureName);

    else if (Feature == "neon" || Feature == "noneon")

      D.Diag(clang::diag::err_drv_no_neon_modifier);

    else

      return false;

    // +sme implies +bf16.

    // +sme-f64f64 and +sme-i16i64 both imply +sme.

    if (Feature == "sme") {

      Features.push_back("+bf16");

    } else if (Feature == "nosme") {

      Features.push_back("-sme-f64f64");

      Features.push_back("-sme-i16i64");

    } else if (Feature == "sme-f64f64") {

      Features.push_back("+sme");

      Features.push_back("+bf16");

    } else if (Feature == "sme-i16i64") {

      Features.push_back("+sme");

      Features.push_back("+bf16");

    } else if (Feature == "nobf16") {

      Features.push_back("-sme");

      Features.push_back("-sme-f64f64");

      Features.push_back("-sme-i16i64");

    }

    if (Feature == "sve2")

      Features.push_back("+sve");

    else if (Feature == "sve2-bitperm" || Feature == "sve2-sha3" ||

             Feature == "sve2-aes" || Feature == "sve2-sm4") {

      Features.push_back("+sve");

      Features.push_back("+sve2");

    } else if (Feature == "nosve") {

      Features.push_back("-sve2");

      Features.push_back("-sve2-bitperm");

      Features.push_back("-sve2-sha3");

      Features.push_back("-sve2-aes");

      Features.push_back("-sve2-sm4");

    } else if (Feature == "nosve2") {

      Features.push_back("-sve2-bitperm");

      Features.push_back("-sve2-sha3");

      Features.push_back("-sve2-aes");

      Features.push_back("-sve2-sm4");

    }

    // +sve implies +f32mm if the base architecture is >= v8.6A (except v9A)

    // It isn't the case in general that sve implies both f64mm and f32mm

    if ((ArchInfo == llvm::AArch64::ARMV8_6A ||

         ArchInfo == llvm::AArch64::ARMV8_7A ||

         ArchInfo == llvm::AArch64::ARMV8_8A ||

         ArchInfo == llvm::AArch64::ARMV8_9A ||

         ArchInfo == llvm::AArch64::ARMV9_1A ||

         ArchInfo == llvm::AArch64::ARMV9_2A ||

         ArchInfo == llvm::AArch64::ARMV9_3A ||

         ArchInfo == llvm::AArch64::ARMV9_4A) &&

        Feature == "sve")

      Features.push_back("+f32mm");

  }

  return true;

}

// Check if the CPU name and feature modifiers in -mcpu are legal. If yes,

// decode CPU and feature.

static bool DecodeAArch64Mcpu(const Driver &D, StringRef Mcpu, StringRef &CPU,

                              std::vector<StringRef> &Features) {

  std::pair<StringRef, StringRef> Split = Mcpu.split("+");

  CPU = Split.first;

  const llvm::AArch64::ArchInfo *ArchInfo = &llvm::AArch64::ARMV8A;

  if (CPU == "native")

    CPU = llvm::sys::getHostCPUName();

  if (CPU == "generic") {

    Features.push_back("+neon");

  } else {

    const std::optional<llvm::AArch64::CpuInfo> CpuInfo =

        llvm::AArch64::parseCpu(CPU);

    if (!CpuInfo)

      return false;

    ArchInfo = &CpuInfo->Arch;

    Features.push_back(ArchInfo->ArchFeature);

    auto Extension = CpuInfo->getImpliedExtensions();

    if (!llvm::AArch64::getExtensionFeatures(Extension, Features))

      return false;

  }

  if (Split.second.size() &&

      !DecodeAArch64Features(D, Split.second, Features, *ArchInfo))

    return false;

  return true;

}

static bool

getAArch64ArchFeaturesFromMarch(const Driver &D, StringRef March,

                                const ArgList &Args,

                                std::vector<StringRef> &Features) {

  std::string MarchLowerCase = March.lower();

  std::pair<StringRef, StringRef> Split = StringRef(MarchLowerCase).split("+");

  std::optional <llvm::AArch64::ArchInfo> ArchInfo =

      llvm::AArch64::parseArch(Split.first);

  if (Split.first == "native")

    ArchInfo = llvm::AArch64::getArchForCpu(llvm::sys::getHostCPUName().str());

  if (!ArchInfo)

    return false;

  Features.push_back(ArchInfo->ArchFeature);

  // Enable SVE2 by default on Armv9-A.

  // It can still be disabled if +nosve2 is present.

  // We must do this early so that DecodeAArch64Features has the correct state

  if ((*ArchInfo == llvm::AArch64::ARMV9A ||

       *ArchInfo == llvm::AArch64::ARMV9_1A ||

       *ArchInfo == llvm::AArch64::ARMV9_2A)) {

    Features.push_back("+sve");

    Features.push_back("+sve2");

  }

  if ((Split.second.size() &&

       !DecodeAArch64Features(D, Split.second, Features, *ArchInfo)))

    return false;

  return true;

}

static bool

getAArch64ArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,

                               const ArgList &Args,

                               std::vector<StringRef> &Features) {

  StringRef CPU;

  std::string McpuLowerCase = Mcpu.lower();

  if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, Features))

    return false;

  return true;

}

static bool

getAArch64MicroArchFeaturesFromMtune(const Driver &D, StringRef Mtune,

                                     const ArgList &Args,

                                     std::vector<StringRef> &Features) {

  std::string MtuneLowerCase = Mtune.lower();

  // Check CPU name is valid

  std::vector<StringRef> MtuneFeatures;

  StringRef Tune;

  if (!DecodeAArch64Mcpu(D, MtuneLowerCase, Tune, MtuneFeatures))

    return false;

  // Handle CPU name is 'native'.

  if (MtuneLowerCase == "native")

    MtuneLowerCase = std::string(llvm::sys::getHostCPUName());

  if (MtuneLowerCase == "cyclone" ||

      StringRef(MtuneLowerCase).starts_with("apple")) {

    Features.push_back("+zcm");

    Features.push_back("+zcz");

  }

  return true;

}

static bool

getAArch64MicroArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,

                                    const ArgList &Args,

                                    std::vector<StringRef> &Features) {

  StringRef CPU;

  std::vector<StringRef> DecodedFeature;

  std::string McpuLowerCase = Mcpu.lower();

  if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, DecodedFeature))

    return false;

  return getAArch64MicroArchFeaturesFromMtune(D, CPU, Args, Features);

}

void aarch64::getAArch64TargetFeatures(const Driver &D,

                                       const llvm::Triple &Triple,

                                       const ArgList &Args,

                                       std::vector<StringRef> &Features,

                                       bool ForAS) {

  Arg *A;

  bool success = true;

  // Enable NEON by default.

  Features.push_back("+neon");

  llvm::StringRef WaMArch;

  if (ForAS)

    for (const auto *A :

         Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler))

      for (StringRef Value : A->getValues())

        if (Value.starts_with("-march="))

          WaMArch = Value.substr(7);

  // Call getAArch64ArchFeaturesFromMarch only if "-Wa,-march=" or

  // "-Xassembler -march" is detected. Otherwise it may return false

  // and causes Clang to error out.

  if (!WaMArch.empty())

    success = getAArch64ArchFeaturesFromMarch(D, WaMArch, Args, Features);

  else if ((A = Args.getLastArg(options::OPT_march_EQ)))

    success = getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, Features);

  else if ((A = Args.getLastArg(options::OPT_mcpu_EQ)))

    success = getAArch64ArchFeaturesFromMcpu(D, A->getValue(), Args, Features);

  else if (isCPUDeterminedByTriple(Triple))

    success = getAArch64ArchFeaturesFromMcpu(

        D, getAArch64TargetCPU(Args, Triple, A), Args, Features);

  else

    // Default to 'A' profile if the architecture is not specified.

    success = getAArch64ArchFeaturesFromMarch(D, "armv8-a", Args, Features);

  if (success && (A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ)))

    success =

        getAArch64MicroArchFeaturesFromMtune(D, A->getValue(), Args, Features);

  else if (success && (A = Args.getLastArg(options::OPT_mcpu_EQ)))

    success =

        getAArch64MicroArchFeaturesFromMcpu(D, A->getValue(), Args, Features);

  else if (success && isCPUDeterminedByTriple(Triple))

    success = getAArch64MicroArchFeaturesFromMcpu(

        D, getAArch64TargetCPU(Args, Triple, A), Args, Features);

  if (!success) {

    auto Diag = D.Diag(diag::err_drv_unsupported_option_argument);

    // If "-Wa,-march=" is used, 'WaMArch' will contain the argument's value,

    // while 'A' is uninitialized. Only dereference 'A' in the other case.

    if (!WaMArch.empty())

      Diag << "-march=" << WaMArch;

    else

      Diag << A->getSpelling() << A->getValue();

  }

  if (Args.getLastArg(options::OPT_mgeneral_regs_only)) {

    Features.push_back("-fp-armv8");

    Features.push_back("-crypto");

    Features.push_back("-neon");

  }

  if (Arg *A = Args.getLastArg(options::OPT_mtp_mode_EQ)) {

    StringRef Mtp = A->getValue();

    if (Mtp == "el3" || Mtp == "tpidr_el3")

      Features.push_back("+tpidr-el3");

    else if (Mtp == "el2" || Mtp == "tpidr_el2")

      Features.push_back("+tpidr-el2");

    else if (Mtp == "el1" || Mtp == "tpidr_el1")

      Features.push_back("+tpidr-el1");

    else if (Mtp == "tpidrro_el0")

      Features.push_back("+tpidrro-el0");

    else if (Mtp != "el0" && Mtp != "tpidr_el0")

      D.Diag(diag::err_drv_invalid_mtp) << A->getAsString(Args);

  }

  // Enable/disable straight line speculation hardening.

  if (Arg *A = Args.getLastArg(options::OPT_mharden_sls_EQ)) {

    StringRef Scope = A->getValue();

    bool EnableRetBr = false;

    bool EnableBlr = false;

    bool DisableComdat = false;

    if (Scope != "none") {

      SmallVector<StringRef, 4> Opts;

      Scope.split(Opts, ",");

      for (auto Opt : Opts) {

        Opt = Opt.trim();

        if (Opt == "all") {

          EnableBlr = true;

          EnableRetBr = true;

          continue;

        }

        if (Opt == "retbr") {

          EnableRetBr = true;

          continue;

        }

        if (Opt == "blr") {

          EnableBlr = true;

          continue;

        }

        if (Opt == "comdat") {

          DisableComdat = false;

          continue;

        }

        if (Opt == "nocomdat") {

          DisableComdat = true;

          continue;

        }

        D.Diag(diag::err_drv_unsupported_option_argument)

            << A->getSpelling() << Scope;

        break;

      }

    }

    if (EnableRetBr)

      Features.push_back("+harden-sls-retbr");

    if (EnableBlr)

      Features.push_back("+harden-sls-blr");

    if (DisableComdat) {

      Features.push_back("+harden-sls-nocomdat");

    }

  }

  // En/disable crc

  if (Arg *A = Args.getLastArg(options::OPT_mcrc, options::OPT_mnocrc)) {

    if (A->getOption().matches(options::OPT_mcrc))

      Features.push_back("+crc");

    else

      Features.push_back("-crc");

  }

  int V8Version = -1;

  int V9Version = -1;

  bool HasNoSM4 = false;

  bool HasNoSHA3 = false;

  bool HasNoSHA2 = false;

  bool HasNoAES = false;

  bool HasSM4 = false;

  bool HasSHA3 = false;

  bool HasSHA2 = false;

  bool HasAES = false;

  bool HasCrypto = false;

  bool HasNoCrypto = false;

  int FullFP16Pos = -1;

  int NoFullFP16Pos = -1;

  int FP16FMLPos = -1;

  int NoFP16FMLPos = -1;

  int ArchFeatPos = -1;

  for (auto I = Features.begin(), E = Features.end(); I != E; I++) {

    if (*I == "+v8a")   V8Version = 0;

    else if (*I == "+v8.1a") V8Version = 1;

    else if (*I == "+v8.2a") V8Version = 2;

    else if (*I == "+v8.3a") V8Version = 3;

    else if (*I == "+v8.4a") V8Version = 4;

    else if (*I == "+v8.5a") V8Version = 5;

    else if (*I == "+v8.6a") V8Version = 6;

    else if (*I == "+v8.7a") V8Version = 7;

    else if (*I == "+v8.8a") V8Version = 8;

    else if (*I == "+v8.9a") V8Version = 9;

    else if (*I == "+v9a")   V9Version = 0;

    else if (*I == "+v9.1a") V9Version = 1;

    else if (*I == "+v9.2a") V9Version = 2;

    else if (*I == "+v9.3a") V9Version = 3;

    else if (*I == "+v9.4a") V9Version = 4;

    else if (*I == "+v9.5a") V9Version = 5;

    else if (*I == "+sm4")  HasSM4 = true;

    else if (*I == "+sha3") HasSHA3 = true;

    else if (*I == "+sha2") HasSHA2 = true;

    else if (*I == "+aes")  HasAES = true;

    else if (*I == "-sm4")  HasNoSM4 = true;

    else if (*I == "-sha3") HasNoSHA3 = true;

    else if (*I == "-sha2") HasNoSHA2 = true;

    else if (*I == "-aes")  HasNoAES = true;

    else if (*I == "+fp16fml")  FP16FMLPos = I - Features.begin();

    else if (*I == "-fp16fml")  NoFP16FMLPos = I - Features.begin();

    else if (*I == "-fullfp16") NoFullFP16Pos = I - Features.begin();

    else if (*I == "+fullfp16") FullFP16Pos = I - Features.begin();

    // Whichever option comes after (right-most option) will win

    else if (*I == "+crypto") {

      HasCrypto = true;

      HasNoCrypto = false;

    } else if (*I == "-crypto" || *I == "-neon") {

      HasCrypto = false;

      HasNoCrypto = true;

      HasSM4 = HasSHA2 = HasSHA3 = HasAES = false;

    }

    // Register the iterator position if this is an architecture feature

    if (ArchFeatPos == -1 && (V8Version != -1 || V9Version != -1))

      ArchFeatPos = I - Features.begin();

  }

  // Handle (arch-dependent) fp16fml/fullfp16 relationship.

  // FIXME: this fp16fml option handling will be reimplemented after the

  // TargetParser rewrite.

  if (V8Version >= 4) {

    // "-fullfp16" "+fullfp16" && "+fp16fml" "+fullfp16" && no "+fullfp16" "-fp16fml" = "+fp16fml"

    if (FullFP16Pos > NoFullFP16Pos && FullFP16Pos > FP16FMLPos && FullFP16Pos > NoFP16FMLPos)

      // Only entangled feature that can be to the right of this +fullfp16 is -fp16fml.

      // Only append the +fp16fml if there is no -fp16fml after the +fullfp16.

      Features.push_back("+fp16fml");

    else

      goto fp16_fml_fallthrough;

  } else {

fp16_fml_fallthrough:

    // In both of these cases, putting the 'other' feature on the end of the vector will

    // result in the same effect as placing it immediately after the current feature.

    // "+fp16fml"  "-fullfp16" = "-fp16fml"

    if (NoFullFP16Pos > FP16FMLPos)

      Features.push_back("-fp16fml");

    // "-fullfp16" "+fp16fml" = "+fullfp16"

    else if (NoFullFP16Pos < FP16FMLPos)

      Features.push_back("+fullfp16");

  }

  // FIXME: this needs reimplementation too after the TargetParser rewrite

  //

  // Context sensitive meaning of Crypto:

  // 1) For Arch >= ARMv8.4a:  crypto = sm4 + sha3 + sha2 + aes

  // 2) For Arch <= ARMv8.3a:  crypto = sha2 + aes

  if (V8Version >= 4 || V9Version >= 0) {

    if (HasCrypto && !HasNoCrypto) {

      // Check if we have NOT disabled an algorithm with something like:

      //   +crypto, -algorithm

      // And if "-algorithm" does not occur, we enable that crypto algorithm.

      if (!HasNoSM4)

        Features.push_back("+sm4");

      if (!HasNoSHA3)

        Features.push_back("+sha3");

      if (!HasNoSHA2)

        Features.push_back("+sha2");

      if (!HasNoAES)

        Features.push_back("+aes");

    } else if (HasNoCrypto) {

      // Check if we have NOT enabled a crypto algorithm with something like:

      //   -crypto, +algorithm

      // And if "+algorithm" does not occur, we disable that crypto algorithm.

      if (!HasSM4)

        Features.push_back("-sm4");

      if (!HasSHA3)

        Features.push_back("-sha3");

      if (!HasSHA2)

        Features.push_back("-sha2");

      if (!HasAES)

        Features.push_back("-aes");

    }

  } else {

    if (HasCrypto && !HasNoCrypto) {

      if (!HasNoSHA2)

        Features.push_back("+sha2");

      if (!HasNoAES)

        Features.push_back("+aes");

    } else if (HasNoCrypto) {

      if (!HasSHA2)

        Features.push_back("-sha2");

      if (!HasAES)

        Features.push_back("-aes");

      if (V8Version == 2 || V8Version == 3) {

        Features.push_back("-sm4");

        Features.push_back("-sha3");

      }

    }

  }

  if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,

                               options::OPT_munaligned_access)) {

    if (A->getOption().matches(options::OPT_mno_unaligned_access))

      Features.push_back("+strict-align");

  } else if (Triple.isOSOpenBSD())

    Features.push_back("+strict-align");

  if (Args.hasArg(options::OPT_ffixed_x1))

    Features.push_back("+reserve-x1");

  if (Args.hasArg(options::OPT_ffixed_x2))

    Features.push_back("+reserve-x2");

  if (Args.hasArg(options::OPT_ffixed_x3))

    Features.push_back("+reserve-x3");

  if (Args.hasArg(options::OPT_ffixed_x4))

    Features.push_back("+reserve-x4");

  if (Args.hasArg(options::OPT_ffixed_x5))

    Features.push_back("+reserve-x5");

  if (Args.hasArg(options::OPT_ffixed_x6))

    Features.push_back("+reserve-x6");

  if (Args.hasArg(options::OPT_ffixed_x7))

    Features.push_back("+reserve-x7");

  if (Args.hasArg(options::OPT_ffixed_x9))

    Features.push_back("+reserve-x9");

  if (Args.hasArg(options::OPT_ffixed_x10))

    Features.push_back("+reserve-x10");

  if (Args.hasArg(options::OPT_ffixed_x11))

    Features.push_back("+reserve-x11");

  if (Args.hasArg(options::OPT_ffixed_x12))

    Features.push_back("+reserve-x12");

  if (Args.hasArg(options::OPT_ffixed_x13))

    Features.push_back("+reserve-x13");

  if (Args.hasArg(options::OPT_ffixed_x14))

    Features.push_back("+reserve-x14");

  if (Args.hasArg(options::OPT_ffixed_x15))

    Features.push_back("+reserve-x15");

  if (Args.hasArg(options::OPT_ffixed_x18))

    Features.push_back("+reserve-x18");

  if (Args.hasArg(options::OPT_ffixed_x20))

    Features.push_back("+reserve-x20");

  if (Args.hasArg(options::OPT_ffixed_x21))

    Features.push_back("+reserve-x21");

  if (Args.hasArg(options::OPT_ffixed_x22))

    Features.push_back("+reserve-x22");

  if (Args.hasArg(options::OPT_ffixed_x23))

    Features.push_back("+reserve-x23");

  if (Args.hasArg(options::OPT_ffixed_x24))

    Features.push_back("+reserve-x24");

  if (Args.hasArg(options::OPT_ffixed_x25))

    Features.push_back("+reserve-x25");

  if (Args.hasArg(options::OPT_ffixed_x26))

    Features.push_back("+reserve-x26");

  if (Args.hasArg(options::OPT_ffixed_x27))

    Features.push_back("+reserve-x27");

  if (Args.hasArg(options::OPT_ffixed_x28))

    Features.push_back("+reserve-x28");

  if (Args.hasArg(options::OPT_ffixed_x30))

    Features.push_back("+reserve-x30");

  if (Args.hasArg(options::OPT_fcall_saved_x8))

    Features.push_back("+call-saved-x8");

  if (Args.hasArg(options::OPT_fcall_saved_x9))

    Features.push_back("+call-saved-x9");

  if (Args.hasArg(options::OPT_fcall_saved_x10))

    Features.push_back("+call-saved-x10");

  if (Args.hasArg(options::OPT_fcall_saved_x11))

    Features.push_back("+call-saved-x11");

  if (Args.hasArg(options::OPT_fcall_saved_x12))

    Features.push_back("+call-saved-x12");

  if (Args.hasArg(options::OPT_fcall_saved_x13))

    Features.push_back("+call-saved-x13");

  if (Args.hasArg(options::OPT_fcall_saved_x14))

    Features.push_back("+call-saved-x14");

  if (Args.hasArg(options::OPT_fcall_saved_x15))

    Features.push_back("+call-saved-x15");

  if (Args.hasArg(options::OPT_fcall_saved_x18))

    Features.push_back("+call-saved-x18");

  if (Args.hasArg(options::OPT_mno_neg_immediates))

    Features.push_back("+no-neg-immediates");

  if (Arg *A = Args.getLastArg(options::OPT_mfix_cortex_a53_835769,

                               options::OPT_mno_fix_cortex_a53_835769)) {

    if (A->getOption().matches(options::OPT_mfix_cortex_a53_835769))

      Features.push_back("+fix-cortex-a53-835769");

    else

      Features.push_back("-fix-cortex-a53-835769");

  } else if (Triple.isAndroid() || Triple.isOHOSFamily()) {

    // Enabled A53 errata (835769) workaround by default on android

    Features.push_back("+fix-cortex-a53-835769");

  } else if (Triple.isOSFuchsia()) {

    std::string CPU = getCPUName(D, Args, Triple);

    if (CPU.empty() || CPU == "generic" || CPU == "cortex-a53")

      Features.push_back("+fix-cortex-a53-835769");

  }

  if (Args.getLastArg(options::OPT_mno_bti_at_return_twice))

    Features.push_back("+no-bti-at-return-twice");

}