1 //===--- X86.cpp - X86 Helpers for Tools ------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "X86.h" 10 #include "ToolChains/CommonArgs.h" 11 #include "clang/Driver/Driver.h" 12 #include "clang/Driver/DriverDiagnostic.h" 13 #include "clang/Driver/Options.h" 14 #include "llvm/ADT/StringExtras.h" 15 #include "llvm/ADT/StringMap.h" 16 #include "llvm/ADT/StringSwitch.h" 17 #include "llvm/Option/ArgList.h" 18 #include "llvm/Support/Host.h" 19 20 using namespace clang::driver; 21 using namespace clang::driver::tools; 22 using namespace clang; 23 using namespace llvm::opt; 24 25 std::string x86::getX86TargetCPU(const Driver &D, const ArgList &Args, 26 const llvm::Triple &Triple) { 27 if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) { 28 StringRef CPU = A->getValue(); 29 if (CPU != "native") 30 return std::string(CPU); 31 32 // FIXME: Reject attempts to use -march=native unless the target matches 33 // the host. 34 // 35 // FIXME: We should also incorporate the detected target features for use 36 // with -native. 37 CPU = llvm::sys::getHostCPUName(); 38 if (!CPU.empty() && CPU != "generic") 39 return std::string(CPU); 40 } 41 42 if (const Arg *A = Args.getLastArg(options::OPT__SLASH_arch)) { 43 // Mapping built by looking at lib/Basic's X86TargetInfo::initFeatureMap(). 44 // The keys are case-sensitive; this matches link.exe. 45 // 32-bit and 64-bit /arch: flags. 46 llvm::StringMap<StringRef> ArchMap({ 47 {"AVX", "sandybridge"}, 48 {"AVX2", "haswell"}, 49 {"AVX512F", "knl"}, 50 {"AVX512", "skylake-avx512"}, 51 }); 52 if (Triple.getArch() == llvm::Triple::x86) { 53 // 32-bit-only /arch: flags. 54 ArchMap.insert({ 55 {"IA32", "i386"}, 56 {"SSE", "pentium3"}, 57 {"SSE2", "pentium4"}, 58 }); 59 } 60 StringRef CPU = ArchMap.lookup(A->getValue()); 61 if (CPU.empty()) { 62 std::vector<StringRef> ValidArchs{ArchMap.keys().begin(), 63 ArchMap.keys().end()}; 64 sort(ValidArchs); 65 D.Diag(diag::warn_drv_invalid_arch_name_with_suggestion) 66 << A->getValue() << (Triple.getArch() == llvm::Triple::x86) 67 << join(ValidArchs, ", "); 68 } 69 return std::string(CPU); 70 } 71 72 // Select the default CPU if none was given (or detection failed). 73 74 if (!Triple.isX86()) 75 return ""; // This routine is only handling x86 targets. 76 77 bool Is64Bit = Triple.getArch() == llvm::Triple::x86_64; 78 79 // FIXME: Need target hooks. 80 if (Triple.isOSDarwin()) { 81 if (Triple.getArchName() == "x86_64h") 82 return "core-avx2"; 83 // macosx10.12 drops support for all pre-Penryn Macs. 84 // Simulators can still run on 10.11 though, like Xcode. 85 if (Triple.isMacOSX() && !Triple.isOSVersionLT(10, 12)) 86 return "penryn"; 87 // The oldest x86_64 Macs have core2/Merom; the oldest x86 Macs have Yonah. 88 return Is64Bit ? "core2" : "yonah"; 89 } 90 91 // Set up default CPU name for PS4 compilers. 92 if (Triple.isPS4CPU()) 93 return "btver2"; 94 95 // On Android use targets compatible with gcc 96 if (Triple.isAndroid()) 97 return Is64Bit ? "x86-64" : "i686"; 98 99 // Everything else goes to x86-64 in 64-bit mode. 100 if (Is64Bit) 101 return "x86-64"; 102 103 switch (Triple.getOS()) { 104 case llvm::Triple::NetBSD: 105 return "i486"; 106 case llvm::Triple::Haiku: 107 case llvm::Triple::OpenBSD: 108 return "i586"; 109 case llvm::Triple::FreeBSD: 110 return "i686"; 111 default: 112 // Fallback to p4. 113 return "pentium4"; 114 } 115 } 116 117 void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple, 118 const ArgList &Args, 119 std::vector<StringRef> &Features) { 120 // If -march=native, autodetect the feature list. 121 if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) { 122 if (StringRef(A->getValue()) == "native") { 123 llvm::StringMap<bool> HostFeatures; 124 if (llvm::sys::getHostCPUFeatures(HostFeatures)) 125 for (auto &F : HostFeatures) 126 Features.push_back( 127 Args.MakeArgString((F.second ? "+" : "-") + F.first())); 128 } 129 } 130 131 if (Triple.getArchName() == "x86_64h") { 132 // x86_64h implies quite a few of the more modern subtarget features 133 // for Haswell class CPUs, but not all of them. Opt-out of a few. 134 Features.push_back("-rdrnd"); 135 Features.push_back("-aes"); 136 Features.push_back("-pclmul"); 137 Features.push_back("-rtm"); 138 Features.push_back("-fsgsbase"); 139 } 140 141 const llvm::Triple::ArchType ArchType = Triple.getArch(); 142 // Add features to be compatible with gcc for Android. 143 if (Triple.isAndroid()) { 144 if (ArchType == llvm::Triple::x86_64) { 145 Features.push_back("+sse4.2"); 146 Features.push_back("+popcnt"); 147 Features.push_back("+cx16"); 148 } else 149 Features.push_back("+ssse3"); 150 } 151 152 // Translate the high level `-mretpoline` flag to the specific target feature 153 // flags. We also detect if the user asked for retpoline external thunks but 154 // failed to ask for retpolines themselves (through any of the different 155 // flags). This is a bit hacky but keeps existing usages working. We should 156 // consider deprecating this and instead warn if the user requests external 157 // retpoline thunks and *doesn't* request some form of retpolines. 158 auto SpectreOpt = clang::driver::options::ID::OPT_INVALID; 159 if (Args.hasArgNoClaim(options::OPT_mretpoline, options::OPT_mno_retpoline, 160 options::OPT_mspeculative_load_hardening, 161 options::OPT_mno_speculative_load_hardening)) { 162 if (Args.hasFlag(options::OPT_mretpoline, options::OPT_mno_retpoline, 163 false)) { 164 Features.push_back("+retpoline-indirect-calls"); 165 Features.push_back("+retpoline-indirect-branches"); 166 SpectreOpt = options::OPT_mretpoline; 167 } else if (Args.hasFlag(options::OPT_mspeculative_load_hardening, 168 options::OPT_mno_speculative_load_hardening, 169 false)) { 170 // On x86, speculative load hardening relies on at least using retpolines 171 // for indirect calls. 172 Features.push_back("+retpoline-indirect-calls"); 173 SpectreOpt = options::OPT_mspeculative_load_hardening; 174 } 175 } else if (Args.hasFlag(options::OPT_mretpoline_external_thunk, 176 options::OPT_mno_retpoline_external_thunk, false)) { 177 // FIXME: Add a warning about failing to specify `-mretpoline` and 178 // eventually switch to an error here. 179 Features.push_back("+retpoline-indirect-calls"); 180 Features.push_back("+retpoline-indirect-branches"); 181 SpectreOpt = options::OPT_mretpoline_external_thunk; 182 } 183 184 auto LVIOpt = clang::driver::options::ID::OPT_INVALID; 185 if (Args.hasFlag(options::OPT_mlvi_hardening, options::OPT_mno_lvi_hardening, 186 false)) { 187 Features.push_back("+lvi-load-hardening"); 188 Features.push_back("+lvi-cfi"); // load hardening implies CFI protection 189 LVIOpt = options::OPT_mlvi_hardening; 190 } else if (Args.hasFlag(options::OPT_mlvi_cfi, options::OPT_mno_lvi_cfi, 191 false)) { 192 Features.push_back("+lvi-cfi"); 193 LVIOpt = options::OPT_mlvi_cfi; 194 } 195 196 if (Args.hasFlag(options::OPT_m_seses, options::OPT_mno_seses, false)) { 197 if (LVIOpt == options::OPT_mlvi_hardening) 198 D.Diag(diag::err_drv_argument_not_allowed_with) 199 << D.getOpts().getOptionName(options::OPT_mlvi_hardening) 200 << D.getOpts().getOptionName(options::OPT_m_seses); 201 202 if (SpectreOpt != clang::driver::options::ID::OPT_INVALID) 203 D.Diag(diag::err_drv_argument_not_allowed_with) 204 << D.getOpts().getOptionName(SpectreOpt) 205 << D.getOpts().getOptionName(options::OPT_m_seses); 206 207 Features.push_back("+seses"); 208 if (!Args.hasArg(options::OPT_mno_lvi_cfi)) { 209 Features.push_back("+lvi-cfi"); 210 LVIOpt = options::OPT_mlvi_cfi; 211 } 212 } 213 214 if (SpectreOpt != clang::driver::options::ID::OPT_INVALID && 215 LVIOpt != clang::driver::options::ID::OPT_INVALID) { 216 D.Diag(diag::err_drv_argument_not_allowed_with) 217 << D.getOpts().getOptionName(SpectreOpt) 218 << D.getOpts().getOptionName(LVIOpt); 219 } 220 221 // Now add any that the user explicitly requested on the command line, 222 // which may override the defaults. 223 for (const Arg *A : Args.filtered(options::OPT_m_x86_Features_Group, 224 options::OPT_mgeneral_regs_only)) { 225 StringRef Name = A->getOption().getName(); 226 A->claim(); 227 228 // Skip over "-m". 229 assert(Name.startswith("m") && "Invalid feature name."); 230 Name = Name.substr(1); 231 232 // Replace -mgeneral-regs-only with -x87, -mmx, -sse 233 if (A->getOption().getID() == options::OPT_mgeneral_regs_only) { 234 Features.insert(Features.end(), {"-x87", "-mmx", "-sse"}); 235 continue; 236 } 237 238 bool IsNegative = Name.startswith("no-"); 239 if (IsNegative) 240 Name = Name.substr(3); 241 Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name)); 242 } 243 } 244