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//===--- X86.cpp - X86 Helpers for Tools ------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "X86.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/Support/Host.h"
using namespace clang::driver;
using namespace clang::driver::tools;
using namespace clang;
using namespace llvm::opt;
const char *x86::getX86TargetCPU(const ArgList &Args,
const llvm::Triple &Triple) {
if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
if (StringRef(A->getValue()) != "native")
return A->getValue();
// FIXME: Reject attempts to use -march=native unless the target matches
// the host.
// FIXME: We should also incorporate the detected target features for use
// with -native.
std::string CPU = llvm::sys::getHostCPUName();
if (!CPU.empty() && CPU != "generic")
return Args.MakeArgString(CPU);
if (const Arg *A = Args.getLastArgNoClaim(options::OPT__SLASH_arch)) {
// Mapping built by looking at lib/Basic's X86TargetInfo::initFeatureMap().
StringRef Arch = A->getValue();
const char *CPU = nullptr;
if (Triple.getArch() == llvm::Triple::x86) { // 32-bit-only /arch: flags.
CPU = llvm::StringSwitch<const char *>(Arch)
.Case("IA32", "i386")
.Case("SSE", "pentium3")
.Case("SSE2", "pentium4")
if (CPU == nullptr) { // 32-bit and 64-bit /arch: flags.
CPU = llvm::StringSwitch<const char *>(Arch)
.Case("AVX", "sandybridge")
.Case("AVX2", "haswell")
.Case("AVX512F", "knl")
.Case("AVX512", "skylake-avx512")
if (CPU) {
return CPU;
// Select the default CPU if none was given (or detection failed).
if (Triple.getArch() != llvm::Triple::x86_64 &&
Triple.getArch() != llvm::Triple::x86)
return nullptr; // This routine is only handling x86 targets.
bool Is64Bit = Triple.getArch() == llvm::Triple::x86_64;
// FIXME: Need target hooks.
if (Triple.isOSDarwin()) {
if (Triple.getArchName() == "x86_64h")
return "core-avx2";
// macosx10.12 drops support for all pre-Penryn Macs.
// Simulators can still run on 10.11 though, like Xcode.
if (Triple.isMacOSX() && !Triple.isOSVersionLT(10, 12))
return "penryn";
// The oldest x86_64 Macs have core2/Merom; the oldest x86 Macs have Yonah.
return Is64Bit ? "core2" : "yonah";
// Set up default CPU name for PS4 compilers.
if (Triple.isPS4CPU())
return "btver2";
// On Android use targets compatible with gcc
if (Triple.isAndroid())
return Is64Bit ? "x86-64" : "i686";
// Everything else goes to x86-64 in 64-bit mode.
if (Is64Bit)
return "x86-64";
switch (Triple.getOS()) {
case llvm::Triple::FreeBSD:
case llvm::Triple::NetBSD:
case llvm::Triple::OpenBSD:
return "i486";
case llvm::Triple::Haiku:
return "i586";
// Fallback to p4.
return "pentium4";
void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args,
std::vector<StringRef> &Features) {
// If -march=native, autodetect the feature list.
if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
if (StringRef(A->getValue()) == "native") {
llvm::StringMap<bool> HostFeatures;
if (llvm::sys::getHostCPUFeatures(HostFeatures))
for (auto &F : HostFeatures)
Args.MakeArgString((F.second ? "+" : "-") + F.first()));
if (Triple.getArchName() == "x86_64h") {
// x86_64h implies quite a few of the more modern subtarget features
// for Haswell class CPUs, but not all of them. Opt-out of a few.
const llvm::Triple::ArchType ArchType = Triple.getArch();
// Add features to be compatible with gcc for Android.
if (Triple.isAndroid()) {
if (ArchType == llvm::Triple::x86_64) {
} else
// Translate the high level `-mretpoline` flag to the specific target feature
// flags. We also detect if the user asked for retpoline external thunks but
// failed to ask for retpolines themselves (through any of the different
// flags). This is a bit hacky but keeps existing usages working. We should
// consider deprecating this and instead warn if the user requests external
// retpoline thunks and *doesn't* request some form of retpolines.
if (Args.hasArgNoClaim(options::OPT_mretpoline, options::OPT_mno_retpoline,
options::OPT_mno_speculative_load_hardening)) {
if (Args.hasFlag(options::OPT_mretpoline, options::OPT_mno_retpoline,
false)) {
} else if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
false)) {
// On x86, speculative load hardening relies on at least using retpolines
// for indirect calls.
} else if (Args.hasFlag(options::OPT_mretpoline_external_thunk,
options::OPT_mno_retpoline_external_thunk, false)) {
// FIXME: Add a warning about failing to specify `-mretpoline` and
// eventually switch to an error here.
// Now add any that the user explicitly requested on the command line,
// which may override the defaults.
handleTargetFeaturesGroup(Args, Features, options::OPT_m_x86_Features_Group);