text: //===--- 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 "clang/Driver/Driver.h"
  #include "clang/Driver/DriverDiagnostic.h"
  #include "clang/Driver/Options.h"
  #include "llvm/Option/ArgList.h"
  #include "llvm/Support/TargetParser.h"
  #include "llvm/Support/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();
    }
  
    // 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 if -arch is used or when
    // targetting a Darwin OS.
    if (Args.getLastArg(options::OPT_arch) || 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,
                                    llvm::AArch64::ArchKind ArchKind) {
    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;
  
      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, v8.7A, v9.1A or
      // v9.2A. It isn't the case in general that sve implies both f64mm and f32mm
      if ((ArchKind == llvm::AArch64::ArchKind::ARMV8_6A ||
           ArchKind == llvm::AArch64::ArchKind::ARMV8_7A ||
           ArchKind == llvm::AArch64::ArchKind::ARMV9_1A ||
           ArchKind == llvm::AArch64::ArchKind::ARMV9_2A) &&
          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;
    llvm::AArch64::ArchKind ArchKind = llvm::AArch64::ArchKind::ARMV8A;
  
    if (CPU == "native")
      CPU = llvm::sys::getHostCPUName();
  
    if (CPU == "generic") {
      Features.push_back("+neon");
    } else {
      ArchKind = llvm::AArch64::parseCPUArch(CPU);
      if (!llvm::AArch64::getArchFeatures(ArchKind, Features))
        return false;
  
      uint64_t Extension = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
      if (!llvm::AArch64::getExtensionFeatures(Extension, Features))
        return false;
     }
  
     if (Split.second.size() &&
         !DecodeAArch64Features(D, Split.second, Features, ArchKind))
       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("+");
  
    llvm::AArch64::ArchKind ArchKind = llvm::AArch64::parseArch(Split.first);
    if (ArchKind == llvm::AArch64::ArchKind::INVALID ||
        !llvm::AArch64::getArchFeatures(ArchKind, Features))
      return false;
  
    // 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 ((ArchKind == llvm::AArch64::ArchKind::ARMV9A ||
         ArchKind == llvm::AArch64::ArchKind::ARMV9_1A ||
         ArchKind == llvm::AArch64::ArchKind::ARMV9_2A)) {
      Features.push_back("+sve");
      Features.push_back("+sve2");
    }
  
    if ((Split.second.size() &&
         !DecodeAArch64Features(D, Split.second, Features, ArchKind)))
      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).startswith("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.startswith("-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 (Args.hasArg(options::OPT_arch) || 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 &&
             (Args.hasArg(options::OPT_arch) || isCPUDeterminedByTriple(Triple)))
      success = getAArch64MicroArchFeaturesFromMcpu(
          D, getAArch64TargetCPU(Args, Triple, A), Args, Features);
  
    if (!success) {
      auto Diag = D.Diag(diag::err_drv_clang_unsupported);
      // 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.str();
      else
        Diag << A->getAsString(Args);
    }
  
    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")
        Features.push_back("+tpidr-el3");
      else if (Mtp == "el2")
        Features.push_back("+tpidr-el2");
      else if (Mtp == "el1")
        Features.push_back("+tpidr-el1");
      else if (Mtp != "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_invalid_sls_hardening)
              << Scope << A->getAsString(Args);
          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");
    }
  
    // Handle (arch-dependent) fp16fml/fullfp16 relationship.
    // FIXME: this fp16fml option handling will be reimplemented after the
    // TargetParser rewrite.
    const auto ItRNoFullFP16 = std::find(Features.rbegin(), Features.rend(), "-fullfp16");
    const auto ItRFP16FML = std::find(Features.rbegin(), Features.rend(), "+fp16fml");
    if (llvm::is_contained(Features, "+v8.4a")) {
      const auto ItRFullFP16  = std::find(Features.rbegin(), Features.rend(), "+fullfp16");
      if (ItRFullFP16 < ItRNoFullFP16 && ItRFullFP16 < ItRFP16FML) {
        // 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.
        if (std::find(Features.rbegin(), ItRFullFP16, "-fp16fml") == ItRFullFP16)
          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.
      if (ItRNoFullFP16 < ItRFP16FML)
        Features.push_back("-fp16fml");
      else if (ItRNoFullFP16 > ItRFP16FML)
        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
    const auto ItBegin = Features.begin();
    const auto ItEnd = Features.end();
    const auto ItRBegin = Features.rbegin();
    const auto ItREnd = Features.rend();
    const auto ItRCrypto = std::find(ItRBegin, ItREnd, "+crypto");
    const auto ItRNoCrypto = std::find(ItRBegin, ItREnd, "-crypto");
    const auto HasCrypto  = ItRCrypto != ItREnd;
    const auto HasNoCrypto = ItRNoCrypto != ItREnd;
    const ptrdiff_t PosCrypto = ItRCrypto - ItRBegin;
    const ptrdiff_t PosNoCrypto = ItRNoCrypto - ItRBegin;
  
    bool NoCrypto = false;
    if (HasCrypto && HasNoCrypto) {
      if (PosNoCrypto < PosCrypto)
        NoCrypto = true;
    }
  
    if (std::find(ItBegin, ItEnd, "+v8.4a") != ItEnd ||
        std::find(ItBegin, ItEnd, "+v9a") != ItEnd ||
        std::find(ItBegin, ItEnd, "+v9.1a") != ItEnd ||
        std::find(ItBegin, ItEnd, "+v9.2a") != ItEnd) {
      if (HasCrypto && !NoCrypto) {
        // Check if we have NOT disabled an algorithm with something like:
        //   +crypto, -algorithm
        // And if "-algorithm" does not occur, we enable that crypto algorithm.
        const bool HasSM4  = (std::find(ItBegin, ItEnd, "-sm4") == ItEnd);
        const bool HasSHA3 = (std::find(ItBegin, ItEnd, "-sha3") == ItEnd);
        const bool HasSHA2 = (std::find(ItBegin, ItEnd, "-sha2") == ItEnd);
        const bool HasAES  = (std::find(ItBegin, ItEnd, "-aes") == ItEnd);
        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 (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.
        const bool HasSM4  = (std::find(ItBegin, ItEnd, "+sm4") != ItEnd);
        const bool HasSHA3 = (std::find(ItBegin, ItEnd, "+sha3") != ItEnd);
        const bool HasSHA2 = (std::find(ItBegin, ItEnd, "+sha2") != ItEnd);
        const bool HasAES  = (std::find(ItBegin, ItEnd, "+aes") != ItEnd);
        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 && !NoCrypto) {
        const bool HasSHA2 = (std::find(ItBegin, ItEnd, "-sha2") == ItEnd);
        const bool HasAES = (std::find(ItBegin, ItEnd, "-aes") == ItEnd);
        if (HasSHA2)
          Features.push_back("+sha2");
        if (HasAES)
          Features.push_back("+aes");
      } else if (HasNoCrypto) {
        const bool HasSHA2 = (std::find(ItBegin, ItEnd, "+sha2") != ItEnd);
        const bool HasAES  = (std::find(ItBegin, ItEnd, "+aes") != ItEnd);
        const bool HasV82a = (std::find(ItBegin, ItEnd, "+v8.2a") != ItEnd);
        const bool HasV83a = (std::find(ItBegin, ItEnd, "+v8.3a") != ItEnd);
        const bool HasV84a = (std::find(ItBegin, ItEnd, "+v8.4a") != ItEnd);
        if (!HasSHA2)
          Features.push_back("-sha2");
        if (!HasAES)
          Features.push_back("-aes");
        if (HasV82a || HasV83a || HasV84a) {
          Features.push_back("-sm4");
          Features.push_back("-sha3");
        }
      }
    }
  
    const char *Archs[] = {"+v8.6a", "+v8.7a", "+v9.1a", "+v9.2a"};
    auto Pos = std::find_first_of(Features.begin(), Features.end(),
                                  std::begin(Archs), std::end(Archs));
    if (Pos != std::end(Features))
      Pos = Features.insert(std::next(Pos), {"+i8mm", "+bf16"});
  
    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()) {
      // Enabled A53 errata (835769) workaround by default on android
      Features.push_back("+fix-cortex-a53-835769");
    }
  }
  