clang/lib/Driver/ToolChains/Arch/X86.cpp

   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/Option/ArgList.h"
  17 #include "llvm/TargetParser/Host.h"
  18
  19 using namespace clang::driver;
  20 using namespace clang::driver::tools;
  21 using namespace clang;
  22 using namespace llvm::opt;
  23
  24 std::string x86::getX86TargetCPU(const Driver &D, const ArgList &Args,
  25                                  const llvm::Triple &Triple) {
  26   if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
  27     StringRef CPU = A->getValue();
  28     if (CPU != "native")
  29       return std::string(CPU);
  30
  31     // FIXME: Reject attempts to use -march=native unless the target matches
  32     // the host.
  33     CPU = llvm::sys::getHostCPUName();
  34     if (!CPU.empty() && CPU != "generic")
  35       return std::string(CPU);
  36   }
  37
  38   if (const Arg *A = Args.getLastArg(options::OPT__SLASH_arch)) {
  39     // Mapping built by looking at lib/Basic's X86TargetInfo::initFeatureMap().
  40     // The keys are case-sensitive; this matches link.exe.
  41     // 32-bit and 64-bit /arch: flags.
  42     llvm::StringMap<StringRef> ArchMap({
  43         {"AVX", "sandybridge"},
  44         {"AVX2", "haswell"},
  45         {"AVX512F", "knl"},
  46         {"AVX512", "skylake-avx512"},
  47     });
  48     if (Triple.getArch() == llvm::Triple::x86) {
  49       // 32-bit-only /arch: flags.
  50       ArchMap.insert({
  51           {"IA32", "i386"},
  52           {"SSE", "pentium3"},
  53           {"SSE2", "pentium4"},
  54       });
  55     }
  56     StringRef CPU = ArchMap.lookup(A->getValue());
  57     if (CPU.empty()) {
  58       std::vector<StringRef> ValidArchs{ArchMap.keys().begin(),
  59                                         ArchMap.keys().end()};
  60       sort(ValidArchs);
  61       D.Diag(diag::warn_drv_invalid_arch_name_with_suggestion)
  62           << A->getValue() << (Triple.getArch() == llvm::Triple::x86)
  63           << join(ValidArchs, ", ");
  64     }
  65     return std::string(CPU);
  66   }
  67
  68   // Select the default CPU if none was given (or detection failed).
  69
  70   if (!Triple.isX86())
  71     return ""; // This routine is only handling x86 targets.
  72
  73   bool Is64Bit = Triple.getArch() == llvm::Triple::x86_64;
  74
  75   // FIXME: Need target hooks.
  76   if (Triple.isOSDarwin()) {
  77     if (Triple.getArchName() == "x86_64h")
  78       return "core-avx2";
  79     // macosx10.12 drops support for all pre-Penryn Macs.
  80     // Simulators can still run on 10.11 though, like Xcode.
  81     if (Triple.isMacOSX() && !Triple.isOSVersionLT(10, 12))
  82       return "penryn";
  83
  84     if (Triple.isDriverKit())
  85       return "nehalem";
  86
  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/PS5 compilers.
  92   if (Triple.isPS4())
  93     return "btver2";
  94   if (Triple.isPS5())
  95     return "znver2";
  96
  97   // On Android use targets compatible with gcc
  98   if (Triple.isAndroid())
  99     return Is64Bit ? "x86-64" : "i686";
 100
 101   // Everything else goes to x86-64 in 64-bit mode.
 102   if (Is64Bit)
 103     return "x86-64";
 104
 105   switch (Triple.getOS()) {
 106   case llvm::Triple::NetBSD:
 107     return "i486";
 108   case llvm::Triple::Haiku:
 109   case llvm::Triple::OpenBSD:
 110     return "i586";
 111   case llvm::Triple::FreeBSD:
 112     return "i686";
 113   default:
 114     // Fallback to p4.
 115     return "pentium4";
 116   }
 117 }
 118
 119 void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
 120                                const ArgList &Args,
 121                                std::vector<StringRef> &Features) {
 122   // Claim and report unsupported -mabi=. Note: we don't support "sysv_abi" or
 123   // "ms_abi" as default function attributes.
 124   if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_mabi_EQ)) {
 125     StringRef DefaultAbi = Triple.isOSWindows() ? "ms" : "sysv";
 126     if (A->getValue() != DefaultAbi)
 127       D.Diag(diag::err_drv_unsupported_opt_for_target)
 128           << A->getSpelling() << Triple.getTriple();
 129   }
 130
 131   // If -march=native, autodetect the feature list.
 132   if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
 133     if (StringRef(A->getValue()) == "native") {
 134       llvm::StringMap<bool> HostFeatures;
 135       if (llvm::sys::getHostCPUFeatures(HostFeatures))
 136         for (auto &F : HostFeatures)
 137           Features.push_back(
 138               Args.MakeArgString((F.second ? "+" : "-") + F.first()));
 139     }
 140   }
 141
 142   if (Triple.getArchName() == "x86_64h") {
 143     // x86_64h implies quite a few of the more modern subtarget features
 144     // for Haswell class CPUs, but not all of them. Opt-out of a few.
 145     Features.push_back("-rdrnd");
 146     Features.push_back("-aes");
 147     Features.push_back("-pclmul");
 148     Features.push_back("-rtm");
 149     Features.push_back("-fsgsbase");
 150   }
 151
 152   const llvm::Triple::ArchType ArchType = Triple.getArch();
 153   // Add features to be compatible with gcc for Android.
 154   if (Triple.isAndroid()) {
 155     if (ArchType == llvm::Triple::x86_64) {
 156       Features.push_back("+sse4.2");
 157       Features.push_back("+popcnt");
 158       Features.push_back("+cx16");
 159     } else
 160       Features.push_back("+ssse3");
 161   }
 162
 163   // Translate the high level `-mretpoline` flag to the specific target feature
 164   // flags. We also detect if the user asked for retpoline external thunks but
 165   // failed to ask for retpolines themselves (through any of the different
 166   // flags). This is a bit hacky but keeps existing usages working. We should
 167   // consider deprecating this and instead warn if the user requests external
 168   // retpoline thunks and *doesn't* request some form of retpolines.
 169   auto SpectreOpt = clang::driver::options::ID::OPT_INVALID;
 170   if (Args.hasArgNoClaim(options::OPT_mretpoline, options::OPT_mno_retpoline,
 171                          options::OPT_mspeculative_load_hardening,
 172                          options::OPT_mno_speculative_load_hardening)) {
 173     if (Args.hasFlag(options::OPT_mretpoline, options::OPT_mno_retpoline,
 174                      false)) {
 175       Features.push_back("+retpoline-indirect-calls");
 176       Features.push_back("+retpoline-indirect-branches");
 177       SpectreOpt = options::OPT_mretpoline;
 178     } else if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
 179                             options::OPT_mno_speculative_load_hardening,
 180                             false)) {
 181       // On x86, speculative load hardening relies on at least using retpolines
 182       // for indirect calls.
 183       Features.push_back("+retpoline-indirect-calls");
 184       SpectreOpt = options::OPT_mspeculative_load_hardening;
 185     }
 186   } else if (Args.hasFlag(options::OPT_mretpoline_external_thunk,
 187                           options::OPT_mno_retpoline_external_thunk, false)) {
 188     // FIXME: Add a warning about failing to specify `-mretpoline` and
 189     // eventually switch to an error here.
 190     Features.push_back("+retpoline-indirect-calls");
 191     Features.push_back("+retpoline-indirect-branches");
 192     SpectreOpt = options::OPT_mretpoline_external_thunk;
 193   }
 194
 195   auto LVIOpt = clang::driver::options::ID::OPT_INVALID;
 196   if (Args.hasFlag(options::OPT_mlvi_hardening, options::OPT_mno_lvi_hardening,
 197                    false)) {
 198     Features.push_back("+lvi-load-hardening");
 199     Features.push_back("+lvi-cfi"); // load hardening implies CFI protection
 200     LVIOpt = options::OPT_mlvi_hardening;
 201   } else if (Args.hasFlag(options::OPT_mlvi_cfi, options::OPT_mno_lvi_cfi,
 202                           false)) {
 203     Features.push_back("+lvi-cfi");
 204     LVIOpt = options::OPT_mlvi_cfi;
 205   }
 206
 207   if (Args.hasFlag(options::OPT_m_seses, options::OPT_mno_seses, false)) {
 208     if (LVIOpt == options::OPT_mlvi_hardening)
 209       D.Diag(diag::err_drv_argument_not_allowed_with)
 210           << D.getOpts().getOptionName(options::OPT_mlvi_hardening)
 211           << D.getOpts().getOptionName(options::OPT_m_seses);
 212
 213     if (SpectreOpt != clang::driver::options::ID::OPT_INVALID)
 214       D.Diag(diag::err_drv_argument_not_allowed_with)
 215           << D.getOpts().getOptionName(SpectreOpt)
 216           << D.getOpts().getOptionName(options::OPT_m_seses);
 217
 218     Features.push_back("+seses");
 219     if (!Args.hasArg(options::OPT_mno_lvi_cfi)) {
 220       Features.push_back("+lvi-cfi");
 221       LVIOpt = options::OPT_mlvi_cfi;
 222     }
 223   }
 224
 225   if (SpectreOpt != clang::driver::options::ID::OPT_INVALID &&
 226       LVIOpt != clang::driver::options::ID::OPT_INVALID) {
 227     D.Diag(diag::err_drv_argument_not_allowed_with)
 228         << D.getOpts().getOptionName(SpectreOpt)
 229         << D.getOpts().getOptionName(LVIOpt);
 230   }
 231
 232   bool HasAVX10 = false;
 233   for (const Arg *A : Args.filtered(options::OPT_m_x86_AVX10_Features_Group)) {
 234     StringRef Name = A->getOption().getName();
 235     A->claim();
 236
 237     // Skip over "-m".
 238     assert(Name.startswith("m") && "Invalid feature name.");
 239     Name = Name.substr(1);
 240
 241     bool IsNegative = Name.startswith("no-");
 242     if (IsNegative)
 243       Name = Name.substr(3);
 244
 245 #ifndef NDEBUG
 246     assert(Name.startswith("avx10.") && "Invalid AVX10 feature name.");
 247     StringRef Version, Width;
 248     std::tie(Version, Width) = Name.substr(6).split('-');
 249     assert(Version == "1" && "Invalid AVX10 feature name.");
 250     assert((Width == "256" || Width == "512") && "Invalid AVX10 feature name.");
 251 #endif
 252
 253     Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name));
 254     HasAVX10 = true;
 255   }
 256
 257   // Now add any that the user explicitly requested on the command line,
 258   // which may override the defaults.
 259   for (const Arg *A : Args.filtered(options::OPT_m_x86_Features_Group,
 260                                     options::OPT_mgeneral_regs_only)) {
 261     StringRef Name = A->getOption().getName();
 262     A->claim();
 263
 264     // Skip over "-m".
 265     assert(Name.startswith("m") && "Invalid feature name.");
 266     Name = Name.substr(1);
 267
 268     // Replace -mgeneral-regs-only with -x87, -mmx, -sse
 269     if (A->getOption().getID() == options::OPT_mgeneral_regs_only) {
 270       Features.insert(Features.end(), {"-x87", "-mmx", "-sse"});
 271       continue;
 272     }
 273
 274     StringRef AVX512Name = Name;
 275     bool IsNegative = Name.startswith("no-");
 276     if (IsNegative)
 277       Name = Name.substr(3);
 278     if (HasAVX10 && (Name.startswith("avx512") || Name == "evex512")) {
 279       D.Diag(diag::warn_drv_unused_argument) << AVX512Name;
 280       continue;
 281     }
 282     Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name));
 283   }
 284
 285   // Enable/disable straight line speculation hardening.
 286   if (Arg *A = Args.getLastArg(options::OPT_mharden_sls_EQ)) {
 287     StringRef Scope = A->getValue();
 288     if (Scope == "all") {
 289       Features.push_back("+harden-sls-ijmp");
 290       Features.push_back("+harden-sls-ret");
 291     } else if (Scope == "return") {
 292       Features.push_back("+harden-sls-ret");
 293     } else if (Scope == "indirect-jmp") {
 294       Features.push_back("+harden-sls-ijmp");
 295     } else if (Scope != "none") {
 296       D.Diag(diag::err_drv_unsupported_option_argument)
 297           << A->getSpelling() << Scope;
 298     }
 299   }
 300
 301   // -mno-gather, -mno-scatter support
 302   if (Args.hasArg(options::OPT_mno_gather))
 303     Features.push_back("+prefer-no-gather");
 304   if (Args.hasArg(options::OPT_mno_scatter))
 305     Features.push_back("+prefer-no-scatter");
 306 }