PPC.cpp

//===--- PPC.cpp - PPC 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 "PPC.h"
#include "ToolChains/CommonArgs.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/Options.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Option/ArgList.h"
#include "llvm/TargetParser/Host.h"

using namespace clang::driver;
using namespace clang::driver::tools;
using namespace clang;
using namespace llvm::opt;

static std::string getPPCGenericTargetCPU(const llvm::Triple &T) {
  // LLVM may default to generating code for the native CPU,
  // but, like gcc, we default to a more generic option for
  // each architecture. (except on AIX)
  if (T.isOSAIX())
    return "pwr7";
  else if (T.getArch() == llvm::Triple::ppc64le)
    return "ppc64le";
  else if (T.getArch() == llvm::Triple::ppc64)
    return "ppc64";
  else
    return "ppc";
}

static std::string normalizeCPUName(StringRef CPUName, const llvm::Triple &T) {
  // Clang/LLVM does not actually support code generation
  // for the 405 CPU. However, there are uses of this CPU ID
  // in projects that previously used GCC and rely on Clang
  // accepting it. Clang has always ignored it and passed the
  // generic CPU ID to the back end.
  if (CPUName == "generic" || CPUName == "405")
    return getPPCGenericTargetCPU(T);

  if (CPUName == "native") {
    std::string CPU = std::string(llvm::sys::getHostCPUName());
    if (!CPU.empty() && CPU != "generic")
      return CPU;
    else
      return getPPCGenericTargetCPU(T);
  }

  return llvm::StringSwitch<const char *>(CPUName)
      .Case("common", "generic")
      .Case("440fp", "440")
      .Case("630", "pwr3")
      .Case("G3", "g3")
      .Case("G4", "g4")
      .Case("G4+", "g4+")
      .Case("8548", "e500")
      .Case("G5", "g5")
      .Case("power3", "pwr3")
      .Case("power4", "pwr4")
      .Case("power5", "pwr5")
      .Case("power5x", "pwr5x")
      .Case("power6", "pwr6")
      .Case("power6x", "pwr6x")
      .Case("power7", "pwr7")
      .Case("power8", "pwr8")
      .Case("power9", "pwr9")
      .Case("power10", "pwr10")
      .Case("power11", "pwr11")
      .Case("future", "future")
      .Case("powerpc", "ppc")
      .Case("powerpc64", "ppc64")
      .Case("powerpc64le", "ppc64le")
      .Default(CPUName.data());
}

/// Get the (LLVM) name of the PowerPC cpu we are tuning for.
std::string ppc::getPPCTuneCPU(const ArgList &Args, const llvm::Triple &T) {
  if (Arg *A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ))
    return normalizeCPUName(A->getValue(), T);
  return getPPCGenericTargetCPU(T);
}

/// Get the (LLVM) name of the PowerPC cpu we are targeting.
std::string ppc::getPPCTargetCPU(const Driver &D, const ArgList &Args,
                                 const llvm::Triple &T) {
  if (Arg *A = Args.getLastArg(clang::driver::options::OPT_mcpu_EQ))
    return normalizeCPUName(A->getValue(), T);
  return getPPCGenericTargetCPU(T);
}

const char *ppc::getPPCAsmModeForCPU(StringRef Name) {
  return llvm::StringSwitch<const char *>(Name)
      .Case("pwr7", "-mpower7")
      .Case("power7", "-mpower7")
      .Case("pwr8", "-mpower8")
      .Case("power8", "-mpower8")
      .Case("ppc64le", "-mpower8")
      .Case("pwr9", "-mpower9")
      .Case("power9", "-mpower9")
      .Case("pwr10", "-mpower10")
      .Case("power10", "-mpower10")
      .Case("pwr11", "-mpower11")
      .Case("power11", "-mpower11")
      .Default("-many");
}

void ppc::getPPCTargetFeatures(const Driver &D, const llvm::Triple &Triple,
                               const ArgList &Args,
                               std::vector<StringRef> &Features) {
  if (Triple.getSubArch() == llvm::Triple::PPCSubArch_spe)
    Features.push_back("+spe");

  handleTargetFeaturesGroup(D, Triple, Args, Features,
                            options::OPT_m_ppc_Features_Group);

  ppc::FloatABI FloatABI = ppc::getPPCFloatABI(D, Args);
  if (FloatABI == ppc::FloatABI::Soft)
    Features.push_back("-hard-float");

  ppc::ReadGOTPtrMode ReadGOT = ppc::getPPCReadGOTPtrMode(D, Triple, Args);
  if (ReadGOT == ppc::ReadGOTPtrMode::SecurePlt)
    Features.push_back("+secure-plt");

  bool UseSeparateSections = isUseSeparateSections(Triple);
  bool HasDefaultDataSections = Triple.isOSBinFormatXCOFF();
  if (Args.hasArg(options::OPT_maix_small_local_exec_tls) ||
      Args.hasArg(options::OPT_maix_small_local_dynamic_tls)) {
    if (!Triple.isOSAIX() || !Triple.isArch64Bit())
      D.Diag(diag::err_opt_not_valid_on_target)
          << "-maix-small-local-[exec|dynamic]-tls";

    // The -maix-small-local-[exec|dynamic]-tls option should only be used with
    // -fdata-sections, as having data sections turned off with this option
    // is not ideal for performance. Moreover, the
    // small-local-[exec|dynamic]-tls region is a limited resource, and should
    // not be used for variables that may be replaced.
    if (!Args.hasFlag(options::OPT_fdata_sections,
                      options::OPT_fno_data_sections,
                      UseSeparateSections || HasDefaultDataSections))
      D.Diag(diag::err_drv_argument_only_allowed_with)
          << "-maix-small-local-[exec|dynamic]-tls" << "-fdata-sections";
  }
}

ppc::ReadGOTPtrMode ppc::getPPCReadGOTPtrMode(const Driver &D, const llvm::Triple &Triple,
                                              const ArgList &Args) {
  if (Args.getLastArg(options::OPT_msecure_plt))
    return ppc::ReadGOTPtrMode::SecurePlt;
  if (Triple.isPPC32SecurePlt())
    return ppc::ReadGOTPtrMode::SecurePlt;
  else
    return ppc::ReadGOTPtrMode::Bss;
}

ppc::FloatABI ppc::getPPCFloatABI(const Driver &D, const ArgList &Args) {
  ppc::FloatABI ABI = ppc::FloatABI::Invalid;
  if (Arg *A =
          Args.getLastArg(options::OPT_msoft_float, options::OPT_mhard_float,
                          options::OPT_mfloat_abi_EQ)) {
    if (A->getOption().matches(options::OPT_msoft_float))
      ABI = ppc::FloatABI::Soft;
    else if (A->getOption().matches(options::OPT_mhard_float))
      ABI = ppc::FloatABI::Hard;
    else {
      ABI = llvm::StringSwitch<ppc::FloatABI>(A->getValue())
                .Case("soft", ppc::FloatABI::Soft)
                .Case("hard", ppc::FloatABI::Hard)
                .Default(ppc::FloatABI::Invalid);
      if (ABI == ppc::FloatABI::Invalid && !StringRef(A->getValue()).empty()) {
        D.Diag(clang::diag::err_drv_invalid_mfloat_abi) << A->getAsString(Args);
        ABI = ppc::FloatABI::Hard;
      }
    }
  }

  // If unspecified, choose the default based on the platform.
  if (ABI == ppc::FloatABI::Invalid) {
    ABI = ppc::FloatABI::Hard;
  }

  return ABI;
}

bool ppc::hasPPCAbiArg(const ArgList &Args, const char *Value) {
  Arg *A = Args.getLastArg(options::OPT_mabi_EQ);
  return A && (A->getValue() == StringRef(Value));
}