1 //===--- WebAssembly.cpp - WebAssembly ToolChain Implementation -*- 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 "WebAssembly.h" 10 #include "CommonArgs.h" 11 #include "Gnu.h" 12 #include "clang/Basic/Version.h" 13 #include "clang/Config/config.h" 14 #include "clang/Driver/Compilation.h" 15 #include "clang/Driver/Driver.h" 16 #include "clang/Driver/DriverDiagnostic.h" 17 #include "clang/Driver/Options.h" 18 #include "llvm/Option/ArgList.h" 19 #include "llvm/Support/FileSystem.h" 20 #include "llvm/Support/Path.h" 21 #include "llvm/Support/VirtualFileSystem.h" 22 23 using namespace clang::driver; 24 using namespace clang::driver::tools; 25 using namespace clang::driver::toolchains; 26 using namespace clang; 27 using namespace llvm::opt; 28 29 /// Following the conventions in https://wiki.debian.org/Multiarch/Tuples, 30 /// we remove the vendor field to form the multiarch triple. 31 std::string WebAssembly::getMultiarchTriple(const Driver &D, 32 const llvm::Triple &TargetTriple, 33 StringRef SysRoot) const { 34 return (TargetTriple.getArchName() + "-" + 35 TargetTriple.getOSAndEnvironmentName()).str(); 36 } 37 38 std::string wasm::Linker::getLinkerPath(const ArgList &Args) const { 39 const ToolChain &ToolChain = getToolChain(); 40 if (const Arg* A = Args.getLastArg(options::OPT_fuse_ld_EQ)) { 41 StringRef UseLinker = A->getValue(); 42 if (!UseLinker.empty()) { 43 if (llvm::sys::path::is_absolute(UseLinker) && 44 llvm::sys::fs::can_execute(UseLinker)) 45 return std::string(UseLinker); 46 47 // Accept 'lld', and 'ld' as aliases for the default linker 48 if (UseLinker != "lld" && UseLinker != "ld") 49 ToolChain.getDriver().Diag(diag::err_drv_invalid_linker_name) 50 << A->getAsString(Args); 51 } 52 } 53 54 return ToolChain.GetProgramPath(ToolChain.getDefaultLinker()); 55 } 56 57 void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA, 58 const InputInfo &Output, 59 const InputInfoList &Inputs, 60 const ArgList &Args, 61 const char *LinkingOutput) const { 62 63 const ToolChain &ToolChain = getToolChain(); 64 const char *Linker = Args.MakeArgString(getLinkerPath(Args)); 65 ArgStringList CmdArgs; 66 67 CmdArgs.push_back("-m"); 68 if (ToolChain.getTriple().isArch64Bit()) 69 CmdArgs.push_back("wasm64"); 70 else 71 CmdArgs.push_back("wasm32"); 72 73 if (Args.hasArg(options::OPT_s)) 74 CmdArgs.push_back("--strip-all"); 75 76 Args.AddAllArgs(CmdArgs, options::OPT_L); 77 Args.AddAllArgs(CmdArgs, options::OPT_u); 78 ToolChain.AddFilePathLibArgs(Args, CmdArgs); 79 80 const char *Crt1 = "crt1.o"; 81 const char *Entry = nullptr; 82 83 // If crt1-command.o exists, it supports new-style commands, so use it. 84 // Otherwise, use the old crt1.o. This is a temporary transition measure. 85 // Once WASI libc no longer needs to support LLVM versions which lack 86 // support for new-style command, it can make crt1.o the same as 87 // crt1-command.o. And once LLVM no longer needs to support WASI libc 88 // versions before that, it can switch to using crt1-command.o. 89 if (ToolChain.GetFilePath("crt1-command.o") != "crt1-command.o") 90 Crt1 = "crt1-command.o"; 91 92 if (const Arg *A = Args.getLastArg(options::OPT_mexec_model_EQ)) { 93 StringRef CM = A->getValue(); 94 if (CM == "command") { 95 // Use default values. 96 } else if (CM == "reactor") { 97 Crt1 = "crt1-reactor.o"; 98 Entry = "_initialize"; 99 } else { 100 ToolChain.getDriver().Diag(diag::err_drv_invalid_argument_to_option) 101 << CM << A->getOption().getName(); 102 } 103 } 104 if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) 105 CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(Crt1))); 106 if (Entry) { 107 CmdArgs.push_back(Args.MakeArgString("--entry")); 108 CmdArgs.push_back(Args.MakeArgString(Entry)); 109 } 110 111 AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA); 112 113 if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) { 114 if (ToolChain.ShouldLinkCXXStdlib(Args)) 115 ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs); 116 117 if (Args.hasArg(options::OPT_pthread)) { 118 CmdArgs.push_back("-lpthread"); 119 CmdArgs.push_back("--shared-memory"); 120 } 121 122 CmdArgs.push_back("-lc"); 123 AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args); 124 } 125 126 CmdArgs.push_back("-o"); 127 CmdArgs.push_back(Output.getFilename()); 128 129 C.addCommand(std::make_unique<Command>(JA, *this, 130 ResponseFileSupport::AtFileCurCP(), 131 Linker, CmdArgs, Inputs, Output)); 132 133 // When optimizing, if wasm-opt is available, run it. 134 if (Arg *A = Args.getLastArg(options::OPT_O_Group)) { 135 auto WasmOptPath = ToolChain.GetProgramPath("wasm-opt"); 136 if (WasmOptPath != "wasm-opt") { 137 StringRef OOpt = "s"; 138 if (A->getOption().matches(options::OPT_O4) || 139 A->getOption().matches(options::OPT_Ofast)) 140 OOpt = "4"; 141 else if (A->getOption().matches(options::OPT_O0)) 142 OOpt = "0"; 143 else if (A->getOption().matches(options::OPT_O)) 144 OOpt = A->getValue(); 145 146 if (OOpt != "0") { 147 const char *WasmOpt = Args.MakeArgString(WasmOptPath); 148 ArgStringList CmdArgs; 149 CmdArgs.push_back(Output.getFilename()); 150 CmdArgs.push_back(Args.MakeArgString(llvm::Twine("-O") + OOpt)); 151 CmdArgs.push_back("-o"); 152 CmdArgs.push_back(Output.getFilename()); 153 C.addCommand(std::make_unique<Command>( 154 JA, *this, ResponseFileSupport::AtFileCurCP(), WasmOpt, CmdArgs, 155 Inputs, Output)); 156 } 157 } 158 } 159 } 160 161 /// Given a base library directory, append path components to form the 162 /// LTO directory. 163 static std::string AppendLTOLibDir(const std::string &Dir) { 164 // The version allows the path to be keyed to the specific version of 165 // LLVM in used, as the bitcode format is not stable. 166 return Dir + "/llvm-lto/" LLVM_VERSION_STRING; 167 } 168 169 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple, 170 const llvm::opt::ArgList &Args) 171 : ToolChain(D, Triple, Args) { 172 173 assert(Triple.isArch32Bit() != Triple.isArch64Bit()); 174 175 getProgramPaths().push_back(getDriver().getInstalledDir()); 176 177 auto SysRoot = getDriver().SysRoot; 178 if (getTriple().getOS() == llvm::Triple::UnknownOS) { 179 // Theoretically an "unknown" OS should mean no standard libraries, however 180 // it could also mean that a custom set of libraries is in use, so just add 181 // /lib to the search path. Disable multiarch in this case, to discourage 182 // paths containing "unknown" from acquiring meanings. 183 getFilePaths().push_back(SysRoot + "/lib"); 184 } else { 185 const std::string MultiarchTriple = 186 getMultiarchTriple(getDriver(), Triple, SysRoot); 187 if (D.isUsingLTO()) { 188 // For LTO, enable use of lto-enabled sysroot libraries too, if available. 189 // Note that the directory is keyed to the LLVM revision, as LLVM's 190 // bitcode format is not stable. 191 auto Dir = AppendLTOLibDir(SysRoot + "/lib/" + MultiarchTriple); 192 getFilePaths().push_back(Dir); 193 } 194 getFilePaths().push_back(SysRoot + "/lib/" + MultiarchTriple); 195 } 196 } 197 198 bool WebAssembly::IsMathErrnoDefault() const { return false; } 199 200 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; } 201 202 bool WebAssembly::UseObjCMixedDispatch() const { return true; } 203 204 bool WebAssembly::isPICDefault() const { return false; } 205 206 bool WebAssembly::isPIEDefault(const llvm::opt::ArgList &Args) const { 207 return false; 208 } 209 210 bool WebAssembly::isPICDefaultForced() const { return false; } 211 212 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; } 213 214 bool WebAssembly::hasBlocksRuntime() const { return false; } 215 216 // TODO: Support profiling. 217 bool WebAssembly::SupportsProfiling() const { return false; } 218 219 bool WebAssembly::HasNativeLLVMSupport() const { return true; } 220 221 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs, 222 ArgStringList &CC1Args, 223 Action::OffloadKind) const { 224 if (!DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array, 225 options::OPT_fno_use_init_array, true)) 226 CC1Args.push_back("-fno-use-init-array"); 227 228 // '-pthread' implies atomics, bulk-memory, mutable-globals, and sign-ext 229 if (DriverArgs.hasFlag(options::OPT_pthread, options::OPT_no_pthread, 230 false)) { 231 if (DriverArgs.hasFlag(options::OPT_mno_atomics, options::OPT_matomics, 232 false)) 233 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 234 << "-pthread" 235 << "-mno-atomics"; 236 if (DriverArgs.hasFlag(options::OPT_mno_bulk_memory, 237 options::OPT_mbulk_memory, false)) 238 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 239 << "-pthread" 240 << "-mno-bulk-memory"; 241 if (DriverArgs.hasFlag(options::OPT_mno_mutable_globals, 242 options::OPT_mmutable_globals, false)) 243 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 244 << "-pthread" 245 << "-mno-mutable-globals"; 246 if (DriverArgs.hasFlag(options::OPT_mno_sign_ext, options::OPT_msign_ext, 247 false)) 248 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 249 << "-pthread" 250 << "-mno-sign-ext"; 251 CC1Args.push_back("-target-feature"); 252 CC1Args.push_back("+atomics"); 253 CC1Args.push_back("-target-feature"); 254 CC1Args.push_back("+bulk-memory"); 255 CC1Args.push_back("-target-feature"); 256 CC1Args.push_back("+mutable-globals"); 257 CC1Args.push_back("-target-feature"); 258 CC1Args.push_back("+sign-ext"); 259 } 260 261 if (!DriverArgs.hasFlag(options::OPT_mmutable_globals, 262 options::OPT_mno_mutable_globals, false)) { 263 // -fPIC implies +mutable-globals because the PIC ABI used by the linker 264 // depends on importing and exporting mutable globals. 265 llvm::Reloc::Model RelocationModel; 266 unsigned PICLevel; 267 bool IsPIE; 268 std::tie(RelocationModel, PICLevel, IsPIE) = 269 ParsePICArgs(*this, DriverArgs); 270 if (RelocationModel == llvm::Reloc::PIC_) { 271 if (DriverArgs.hasFlag(options::OPT_mno_mutable_globals, 272 options::OPT_mmutable_globals, false)) { 273 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 274 << "-fPIC" 275 << "-mno-mutable-globals"; 276 } 277 CC1Args.push_back("-target-feature"); 278 CC1Args.push_back("+mutable-globals"); 279 } 280 } 281 282 if (DriverArgs.getLastArg(options::OPT_fwasm_exceptions)) { 283 // '-fwasm-exceptions' is not compatible with '-mno-exception-handling' 284 if (DriverArgs.hasFlag(options::OPT_mno_exception_handing, 285 options::OPT_mexception_handing, false)) 286 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 287 << "-fwasm-exceptions" 288 << "-mno-exception-handling"; 289 // '-fwasm-exceptions' is not compatible with 290 // '-mllvm -enable-emscripten-cxx-exceptions' 291 for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) { 292 if (StringRef(A->getValue(0)) == "-enable-emscripten-cxx-exceptions") 293 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 294 << "-fwasm-exceptions" 295 << "-mllvm -enable-emscripten-cxx-exceptions"; 296 } 297 // '-fwasm-exceptions' implies exception-handling feature 298 CC1Args.push_back("-target-feature"); 299 CC1Args.push_back("+exception-handling"); 300 // Backend needs -wasm-enable-eh to enable Wasm EH 301 CC1Args.push_back("-mllvm"); 302 CC1Args.push_back("-wasm-enable-eh"); 303 } 304 305 for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) { 306 StringRef Opt = A->getValue(0); 307 if (Opt.startswith("-emscripten-cxx-exceptions-allowed")) { 308 // '-mllvm -emscripten-cxx-exceptions-allowed' should be used with 309 // '-mllvm -enable-emscripten-cxx-exceptions' 310 bool EmEHArgExists = false; 311 for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) { 312 if (StringRef(A->getValue(0)) == "-enable-emscripten-cxx-exceptions") { 313 EmEHArgExists = true; 314 break; 315 } 316 } 317 if (!EmEHArgExists) 318 getDriver().Diag(diag::err_drv_argument_only_allowed_with) 319 << "-mllvm -emscripten-cxx-exceptions-allowed" 320 << "-mllvm -enable-emscripten-cxx-exceptions"; 321 322 // Prevent functions specified in -emscripten-cxx-exceptions-allowed list 323 // from being inlined before reaching the wasm backend. 324 StringRef FuncNamesStr = Opt.split('=').second; 325 SmallVector<StringRef, 4> FuncNames; 326 FuncNamesStr.split(FuncNames, ','); 327 for (auto Name : FuncNames) { 328 CC1Args.push_back("-mllvm"); 329 CC1Args.push_back(DriverArgs.MakeArgString("--force-attribute=" + Name + 330 ":noinline")); 331 } 332 } 333 334 if (Opt.startswith("-wasm-enable-sjlj")) { 335 // '-mllvm -wasm-enable-sjlj' is not compatible with 336 // '-mno-exception-handling' 337 if (DriverArgs.hasFlag(options::OPT_mno_exception_handing, 338 options::OPT_mexception_handing, false)) 339 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 340 << "-mllvm -wasm-enable-sjlj" 341 << "-mno-exception-handling"; 342 // '-mllvm -wasm-enable-sjlj' is not compatible with 343 // '-mllvm -enable-emscripten-cxx-exceptions' 344 // because we don't allow Emscripten EH + Wasm SjLj 345 for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) { 346 if (StringRef(A->getValue(0)) == "-enable-emscripten-cxx-exceptions") 347 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 348 << "-mllvm -wasm-enable-sjlj" 349 << "-mllvm -enable-emscripten-cxx-exceptions"; 350 } 351 // '-mllvm -wasm-enable-sjlj' is not compatible with 352 // '-mllvm -enable-emscripten-sjlj' 353 for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) { 354 if (StringRef(A->getValue(0)) == "-enable-emscripten-sjlj") 355 getDriver().Diag(diag::err_drv_argument_not_allowed_with) 356 << "-mllvm -wasm-enable-sjlj" 357 << "-mllvm -enable-emscripten-sjlj"; 358 } 359 // '-mllvm -wasm-enable-sjlj' implies exception-handling feature 360 CC1Args.push_back("-target-feature"); 361 CC1Args.push_back("+exception-handling"); 362 // Backend needs '-exception-model=wasm' to use Wasm EH instructions 363 CC1Args.push_back("-exception-model=wasm"); 364 } 365 } 366 } 367 368 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const { 369 return ToolChain::RLT_CompilerRT; 370 } 371 372 ToolChain::CXXStdlibType 373 WebAssembly::GetCXXStdlibType(const ArgList &Args) const { 374 if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) { 375 StringRef Value = A->getValue(); 376 if (Value == "libc++") 377 return ToolChain::CST_Libcxx; 378 else if (Value == "libstdc++") 379 return ToolChain::CST_Libstdcxx; 380 else 381 getDriver().Diag(diag::err_drv_invalid_stdlib_name) 382 << A->getAsString(Args); 383 } 384 return ToolChain::CST_Libcxx; 385 } 386 387 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs, 388 ArgStringList &CC1Args) const { 389 if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc)) 390 return; 391 392 const Driver &D = getDriver(); 393 394 if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) { 395 SmallString<128> P(D.ResourceDir); 396 llvm::sys::path::append(P, "include"); 397 addSystemInclude(DriverArgs, CC1Args, P); 398 } 399 400 if (DriverArgs.hasArg(options::OPT_nostdlibinc)) 401 return; 402 403 // Check for configure-time C include directories. 404 StringRef CIncludeDirs(C_INCLUDE_DIRS); 405 if (CIncludeDirs != "") { 406 SmallVector<StringRef, 5> dirs; 407 CIncludeDirs.split(dirs, ":"); 408 for (StringRef dir : dirs) { 409 StringRef Prefix = 410 llvm::sys::path::is_absolute(dir) ? "" : StringRef(D.SysRoot); 411 addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir); 412 } 413 return; 414 } 415 416 if (getTriple().getOS() != llvm::Triple::UnknownOS) { 417 const std::string MultiarchTriple = 418 getMultiarchTriple(D, getTriple(), D.SysRoot); 419 addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include/" + MultiarchTriple); 420 } 421 addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include"); 422 } 423 424 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs, 425 ArgStringList &CC1Args) const { 426 427 if (DriverArgs.hasArg(options::OPT_nostdlibinc) || 428 DriverArgs.hasArg(options::OPT_nostdincxx)) 429 return; 430 431 switch (GetCXXStdlibType(DriverArgs)) { 432 case ToolChain::CST_Libcxx: 433 addLibCxxIncludePaths(DriverArgs, CC1Args); 434 break; 435 case ToolChain::CST_Libstdcxx: 436 addLibStdCXXIncludePaths(DriverArgs, CC1Args); 437 break; 438 } 439 } 440 441 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args, 442 llvm::opt::ArgStringList &CmdArgs) const { 443 444 switch (GetCXXStdlibType(Args)) { 445 case ToolChain::CST_Libcxx: 446 CmdArgs.push_back("-lc++"); 447 if (Args.hasArg(options::OPT_fexperimental_library)) 448 CmdArgs.push_back("-lc++experimental"); 449 CmdArgs.push_back("-lc++abi"); 450 break; 451 case ToolChain::CST_Libstdcxx: 452 CmdArgs.push_back("-lstdc++"); 453 break; 454 } 455 } 456 457 SanitizerMask WebAssembly::getSupportedSanitizers() const { 458 SanitizerMask Res = ToolChain::getSupportedSanitizers(); 459 if (getTriple().isOSEmscripten()) { 460 Res |= SanitizerKind::Vptr | SanitizerKind::Leak | SanitizerKind::Address; 461 } 462 return Res; 463 } 464 465 Tool *WebAssembly::buildLinker() const { 466 return new tools::wasm::Linker(*this); 467 } 468 469 void WebAssembly::addLibCxxIncludePaths( 470 const llvm::opt::ArgList &DriverArgs, 471 llvm::opt::ArgStringList &CC1Args) const { 472 const Driver &D = getDriver(); 473 std::string SysRoot = computeSysRoot(); 474 std::string LibPath = SysRoot + "/include"; 475 const std::string MultiarchTriple = 476 getMultiarchTriple(D, getTriple(), SysRoot); 477 bool IsKnownOs = (getTriple().getOS() != llvm::Triple::UnknownOS); 478 479 std::string Version = detectLibcxxVersion(LibPath); 480 if (Version.empty()) 481 return; 482 483 // First add the per-target include path if the OS is known. 484 if (IsKnownOs) { 485 std::string TargetDir = LibPath + "/" + MultiarchTriple + "/c++/" + Version; 486 addSystemInclude(DriverArgs, CC1Args, TargetDir); 487 } 488 489 // Second add the generic one. 490 addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version); 491 } 492 493 void WebAssembly::addLibStdCXXIncludePaths( 494 const llvm::opt::ArgList &DriverArgs, 495 llvm::opt::ArgStringList &CC1Args) const { 496 // We cannot use GCCInstallationDetector here as the sysroot usually does 497 // not contain a full GCC installation. 498 // Instead, we search the given sysroot for /usr/include/xx, similar 499 // to how we do it for libc++. 500 const Driver &D = getDriver(); 501 std::string SysRoot = computeSysRoot(); 502 std::string LibPath = SysRoot + "/include"; 503 const std::string MultiarchTriple = 504 getMultiarchTriple(D, getTriple(), SysRoot); 505 bool IsKnownOs = (getTriple().getOS() != llvm::Triple::UnknownOS); 506 507 // This is similar to detectLibcxxVersion() 508 std::string Version; 509 { 510 std::error_code EC; 511 Generic_GCC::GCCVersion MaxVersion = 512 Generic_GCC::GCCVersion::Parse("0.0.0"); 513 SmallString<128> Path(LibPath); 514 llvm::sys::path::append(Path, "c++"); 515 for (llvm::vfs::directory_iterator LI = getVFS().dir_begin(Path, EC), LE; 516 !EC && LI != LE; LI = LI.increment(EC)) { 517 StringRef VersionText = llvm::sys::path::filename(LI->path()); 518 if (VersionText[0] != 'v') { 519 auto Version = Generic_GCC::GCCVersion::Parse(VersionText); 520 if (Version > MaxVersion) 521 MaxVersion = Version; 522 } 523 } 524 if (MaxVersion.Major > 0) 525 Version = MaxVersion.Text; 526 } 527 528 if (Version.empty()) 529 return; 530 531 // First add the per-target include path if the OS is known. 532 if (IsKnownOs) { 533 std::string TargetDir = LibPath + "/c++/" + Version + "/" + MultiarchTriple; 534 addSystemInclude(DriverArgs, CC1Args, TargetDir); 535 } 536 537 // Second add the generic one. 538 addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version); 539 // Third the backward one. 540 addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version + "/backward"); 541 } 542