1 //===--- Linux.h - Linux ToolChain Implementations --------------*- 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 "Linux.h"
10 #include "Arch/ARM.h"
11 #include "Arch/Mips.h"
12 #include "Arch/PPC.h"
13 #include "Arch/RISCV.h"
14 #include "CommonArgs.h"
15 #include "clang/Config/config.h"
16 #include "clang/Driver/Distro.h"
17 #include "clang/Driver/Driver.h"
18 #include "clang/Driver/Options.h"
19 #include "clang/Driver/SanitizerArgs.h"
20 #include "llvm/Option/ArgList.h"
21 #include "llvm/ProfileData/InstrProf.h"
22 #include "llvm/Support/Path.h"
23 #include "llvm/Support/ScopedPrinter.h"
24 #include "llvm/Support/VirtualFileSystem.h"
25 #include <system_error>
26 
27 using namespace clang::driver;
28 using namespace clang::driver::toolchains;
29 using namespace clang;
30 using namespace llvm::opt;
31 
32 using tools::addPathIfExists;
33 
34 /// Get our best guess at the multiarch triple for a target.
35 ///
36 /// Debian-based systems are starting to use a multiarch setup where they use
37 /// a target-triple directory in the library and header search paths.
38 /// Unfortunately, this triple does not align with the vanilla target triple,
39 /// so we provide a rough mapping here.
40 std::string Linux::getMultiarchTriple(const Driver &D,
41                                       const llvm::Triple &TargetTriple,
42                                       StringRef SysRoot) const {
43   llvm::Triple::EnvironmentType TargetEnvironment =
44       TargetTriple.getEnvironment();
45   bool IsAndroid = TargetTriple.isAndroid();
46   bool IsMipsR6 = TargetTriple.getSubArch() == llvm::Triple::MipsSubArch_r6;
47   bool IsMipsN32Abi = TargetTriple.getEnvironment() == llvm::Triple::GNUABIN32;
48 
49   // For most architectures, just use whatever we have rather than trying to be
50   // clever.
51   switch (TargetTriple.getArch()) {
52   default:
53     break;
54 
55   // We use the existence of '/lib/<triple>' as a directory to detect some
56   // common linux triples that don't quite match the Clang triple for both
57   // 32-bit and 64-bit targets. Multiarch fixes its install triples to these
58   // regardless of what the actual target triple is.
59   case llvm::Triple::arm:
60   case llvm::Triple::thumb:
61     if (IsAndroid) {
62       return "arm-linux-androideabi";
63     } else if (TargetEnvironment == llvm::Triple::GNUEABIHF) {
64       if (D.getVFS().exists(SysRoot + "/lib/arm-linux-gnueabihf"))
65         return "arm-linux-gnueabihf";
66     } else {
67       if (D.getVFS().exists(SysRoot + "/lib/arm-linux-gnueabi"))
68         return "arm-linux-gnueabi";
69     }
70     break;
71   case llvm::Triple::armeb:
72   case llvm::Triple::thumbeb:
73     if (TargetEnvironment == llvm::Triple::GNUEABIHF) {
74       if (D.getVFS().exists(SysRoot + "/lib/armeb-linux-gnueabihf"))
75         return "armeb-linux-gnueabihf";
76     } else {
77       if (D.getVFS().exists(SysRoot + "/lib/armeb-linux-gnueabi"))
78         return "armeb-linux-gnueabi";
79     }
80     break;
81   case llvm::Triple::x86:
82     if (IsAndroid)
83       return "i686-linux-android";
84     if (D.getVFS().exists(SysRoot + "/lib/i386-linux-gnu"))
85       return "i386-linux-gnu";
86     break;
87   case llvm::Triple::x86_64:
88     if (IsAndroid)
89       return "x86_64-linux-android";
90     // We don't want this for x32, otherwise it will match x86_64 libs
91     if (TargetEnvironment != llvm::Triple::GNUX32 &&
92         D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnu"))
93       return "x86_64-linux-gnu";
94     break;
95   case llvm::Triple::aarch64:
96     if (IsAndroid)
97       return "aarch64-linux-android";
98     if (D.getVFS().exists(SysRoot + "/lib/aarch64-linux-gnu"))
99       return "aarch64-linux-gnu";
100     break;
101   case llvm::Triple::aarch64_be:
102     if (D.getVFS().exists(SysRoot + "/lib/aarch64_be-linux-gnu"))
103       return "aarch64_be-linux-gnu";
104     break;
105 
106   case llvm::Triple::m68k:
107     if (D.getVFS().exists(SysRoot + "/lib/m68k-linux-gnu"))
108       return "m68k-linux-gnu";
109     break;
110 
111   case llvm::Triple::mips: {
112     std::string MT = IsMipsR6 ? "mipsisa32r6-linux-gnu" : "mips-linux-gnu";
113     if (D.getVFS().exists(SysRoot + "/lib/" + MT))
114       return MT;
115     break;
116   }
117   case llvm::Triple::mipsel: {
118     if (IsAndroid)
119       return "mipsel-linux-android";
120     std::string MT = IsMipsR6 ? "mipsisa32r6el-linux-gnu" : "mipsel-linux-gnu";
121     if (D.getVFS().exists(SysRoot + "/lib/" + MT))
122       return MT;
123     break;
124   }
125   case llvm::Triple::mips64: {
126     std::string MT = std::string(IsMipsR6 ? "mipsisa64r6" : "mips64") +
127                      "-linux-" + (IsMipsN32Abi ? "gnuabin32" : "gnuabi64");
128     if (D.getVFS().exists(SysRoot + "/lib/" + MT))
129       return MT;
130     if (D.getVFS().exists(SysRoot + "/lib/mips64-linux-gnu"))
131       return "mips64-linux-gnu";
132     break;
133   }
134   case llvm::Triple::mips64el: {
135     if (IsAndroid)
136       return "mips64el-linux-android";
137     std::string MT = std::string(IsMipsR6 ? "mipsisa64r6el" : "mips64el") +
138                      "-linux-" + (IsMipsN32Abi ? "gnuabin32" : "gnuabi64");
139     if (D.getVFS().exists(SysRoot + "/lib/" + MT))
140       return MT;
141     if (D.getVFS().exists(SysRoot + "/lib/mips64el-linux-gnu"))
142       return "mips64el-linux-gnu";
143     break;
144   }
145   case llvm::Triple::ppc:
146     if (D.getVFS().exists(SysRoot + "/lib/powerpc-linux-gnuspe"))
147       return "powerpc-linux-gnuspe";
148     if (D.getVFS().exists(SysRoot + "/lib/powerpc-linux-gnu"))
149       return "powerpc-linux-gnu";
150     break;
151   case llvm::Triple::ppcle:
152     if (D.getVFS().exists(SysRoot + "/lib/powerpcle-linux-gnu"))
153       return "powerpcle-linux-gnu";
154     break;
155   case llvm::Triple::ppc64:
156     if (D.getVFS().exists(SysRoot + "/lib/powerpc64-linux-gnu"))
157       return "powerpc64-linux-gnu";
158     break;
159   case llvm::Triple::ppc64le:
160     if (D.getVFS().exists(SysRoot + "/lib/powerpc64le-linux-gnu"))
161       return "powerpc64le-linux-gnu";
162     break;
163   case llvm::Triple::sparc:
164     if (D.getVFS().exists(SysRoot + "/lib/sparc-linux-gnu"))
165       return "sparc-linux-gnu";
166     break;
167   case llvm::Triple::sparcv9:
168     if (D.getVFS().exists(SysRoot + "/lib/sparc64-linux-gnu"))
169       return "sparc64-linux-gnu";
170     break;
171   case llvm::Triple::systemz:
172     if (D.getVFS().exists(SysRoot + "/lib/s390x-linux-gnu"))
173       return "s390x-linux-gnu";
174     break;
175   }
176   return TargetTriple.str();
177 }
178 
179 static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {
180   if (Triple.isMIPS()) {
181     if (Triple.isAndroid()) {
182       StringRef CPUName;
183       StringRef ABIName;
184       tools::mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
185       if (CPUName == "mips32r6")
186         return "libr6";
187       if (CPUName == "mips32r2")
188         return "libr2";
189     }
190     // lib32 directory has a special meaning on MIPS targets.
191     // It contains N32 ABI binaries. Use this folder if produce
192     // code for N32 ABI only.
193     if (tools::mips::hasMipsAbiArg(Args, "n32"))
194       return "lib32";
195     return Triple.isArch32Bit() ? "lib" : "lib64";
196   }
197 
198   // It happens that only x86, PPC and SPARC use the 'lib32' variant of
199   // oslibdir, and using that variant while targeting other architectures causes
200   // problems because the libraries are laid out in shared system roots that
201   // can't cope with a 'lib32' library search path being considered. So we only
202   // enable them when we know we may need it.
203   //
204   // FIXME: This is a bit of a hack. We should really unify this code for
205   // reasoning about oslibdir spellings with the lib dir spellings in the
206   // GCCInstallationDetector, but that is a more significant refactoring.
207   if (Triple.getArch() == llvm::Triple::x86 || Triple.isPPC32() ||
208       Triple.getArch() == llvm::Triple::sparc)
209     return "lib32";
210 
211   if (Triple.getArch() == llvm::Triple::x86_64 &&
212       Triple.getEnvironment() == llvm::Triple::GNUX32)
213     return "libx32";
214 
215   if (Triple.getArch() == llvm::Triple::riscv32)
216     return "lib32";
217 
218   return Triple.isArch32Bit() ? "lib" : "lib64";
219 }
220 
221 Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
222     : Generic_ELF(D, Triple, Args) {
223   GCCInstallation.init(Triple, Args);
224   Multilibs = GCCInstallation.getMultilibs();
225   SelectedMultilib = GCCInstallation.getMultilib();
226   llvm::Triple::ArchType Arch = Triple.getArch();
227   std::string SysRoot = computeSysRoot();
228   ToolChain::path_list &PPaths = getProgramPaths();
229 
230   Generic_GCC::PushPPaths(PPaths);
231 
232   Distro Distro(D.getVFS(), Triple);
233 
234   if (Distro.IsAlpineLinux() || Triple.isAndroid()) {
235     ExtraOpts.push_back("-z");
236     ExtraOpts.push_back("now");
237   }
238 
239   if (Distro.IsOpenSUSE() || Distro.IsUbuntu() || Distro.IsAlpineLinux() ||
240       Triple.isAndroid()) {
241     ExtraOpts.push_back("-z");
242     ExtraOpts.push_back("relro");
243   }
244 
245   // Android ARM/AArch64 use max-page-size=4096 to reduce VMA usage. Note, lld
246   // from 11 onwards default max-page-size to 65536 for both ARM and AArch64.
247   if ((Triple.isARM() || Triple.isAArch64()) && Triple.isAndroid()) {
248     ExtraOpts.push_back("-z");
249     ExtraOpts.push_back("max-page-size=4096");
250   }
251 
252   if (GCCInstallation.getParentLibPath().find("opt/rh/devtoolset") !=
253       StringRef::npos)
254     // With devtoolset on RHEL, we want to add a bin directory that is relative
255     // to the detected gcc install, because if we are using devtoolset gcc then
256     // we want to use other tools from devtoolset (e.g. ld) instead of the
257     // standard system tools.
258     PPaths.push_back(Twine(GCCInstallation.getParentLibPath() +
259                      "/../bin").str());
260 
261   if (Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb)
262     ExtraOpts.push_back("-X");
263 
264   const bool IsAndroid = Triple.isAndroid();
265   const bool IsMips = Triple.isMIPS();
266   const bool IsHexagon = Arch == llvm::Triple::hexagon;
267   const bool IsRISCV = Triple.isRISCV();
268 
269   if (IsMips && !SysRoot.empty())
270     ExtraOpts.push_back("--sysroot=" + SysRoot);
271 
272   // Do not use 'gnu' hash style for Mips targets because .gnu.hash
273   // and the MIPS ABI require .dynsym to be sorted in different ways.
274   // .gnu.hash needs symbols to be grouped by hash code whereas the MIPS
275   // ABI requires a mapping between the GOT and the symbol table.
276   // Android loader does not support .gnu.hash until API 23.
277   // Hexagon linker/loader does not support .gnu.hash
278   if (!IsMips && !IsHexagon) {
279     if (Distro.IsRedhat() || Distro.IsOpenSUSE() || Distro.IsAlpineLinux() ||
280         (Distro.IsUbuntu() && Distro >= Distro::UbuntuMaverick) ||
281         (IsAndroid && !Triple.isAndroidVersionLT(23)))
282       ExtraOpts.push_back("--hash-style=gnu");
283 
284     if (Distro.IsDebian() || Distro.IsOpenSUSE() ||
285         Distro == Distro::UbuntuLucid || Distro == Distro::UbuntuJaunty ||
286         Distro == Distro::UbuntuKarmic ||
287         (IsAndroid && Triple.isAndroidVersionLT(23)))
288       ExtraOpts.push_back("--hash-style=both");
289   }
290 
291 #ifdef ENABLE_LINKER_BUILD_ID
292   ExtraOpts.push_back("--build-id");
293 #endif
294 
295   if (IsAndroid || Distro.IsOpenSUSE())
296     ExtraOpts.push_back("--enable-new-dtags");
297 
298   // The selection of paths to try here is designed to match the patterns which
299   // the GCC driver itself uses, as this is part of the GCC-compatible driver.
300   // This was determined by running GCC in a fake filesystem, creating all
301   // possible permutations of these directories, and seeing which ones it added
302   // to the link paths.
303   path_list &Paths = getFilePaths();
304 
305   const std::string OSLibDir = std::string(getOSLibDir(Triple, Args));
306   const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);
307 
308   Generic_GCC::AddMultilibPaths(D, SysRoot, OSLibDir, MultiarchTriple, Paths);
309 
310   // Similar to the logic for GCC above, if we currently running Clang inside
311   // of the requested system root, add its parent library paths to
312   // those searched.
313   // FIXME: It's not clear whether we should use the driver's installed
314   // directory ('Dir' below) or the ResourceDir.
315   if (StringRef(D.Dir).startswith(SysRoot)) {
316     addPathIfExists(D, D.Dir + "/../lib/" + MultiarchTriple, Paths);
317     addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
318   }
319 
320   addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
321   addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
322 
323   if (IsAndroid) {
324     // Android sysroots contain a library directory for each supported OS
325     // version as well as some unversioned libraries in the usual multiarch
326     // directory.
327     unsigned Major;
328     unsigned Minor;
329     unsigned Micro;
330     Triple.getEnvironmentVersion(Major, Minor, Micro);
331     addPathIfExists(D,
332                     SysRoot + "/usr/lib/" + MultiarchTriple + "/" +
333                         llvm::to_string(Major),
334                     Paths);
335   }
336 
337   addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
338   // 64-bit OpenEmbedded sysroots may not have a /usr/lib dir. So they cannot
339   // find /usr/lib64 as it is referenced as /usr/lib/../lib64. So we handle
340   // this here.
341   if (Triple.getVendor() == llvm::Triple::OpenEmbedded &&
342       Triple.isArch64Bit())
343     addPathIfExists(D, SysRoot + "/usr/" + OSLibDir, Paths);
344   else
345     addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
346   if (IsRISCV) {
347     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
348     addPathIfExists(D, SysRoot + "/" + OSLibDir + "/" + ABIName, Paths);
349     addPathIfExists(D, SysRoot + "/usr/" + OSLibDir + "/" + ABIName, Paths);
350   }
351 
352   Generic_GCC::AddMultiarchPaths(D, SysRoot, OSLibDir, Paths);
353 
354   // Similar to the logic for GCC above, if we are currently running Clang
355   // inside of the requested system root, add its parent library path to those
356   // searched.
357   // FIXME: It's not clear whether we should use the driver's installed
358   // directory ('Dir' below) or the ResourceDir.
359   if (StringRef(D.Dir).startswith(SysRoot))
360     addPathIfExists(D, D.Dir + "/../lib", Paths);
361 
362   addPathIfExists(D, SysRoot + "/lib", Paths);
363   addPathIfExists(D, SysRoot + "/usr/lib", Paths);
364 }
365 
366 ToolChain::RuntimeLibType Linux::GetDefaultRuntimeLibType() const {
367   if (getTriple().isAndroid())
368     return ToolChain::RLT_CompilerRT;
369   return Generic_ELF::GetDefaultRuntimeLibType();
370 }
371 
372 ToolChain::CXXStdlibType Linux::GetDefaultCXXStdlibType() const {
373   if (getTriple().isAndroid())
374     return ToolChain::CST_Libcxx;
375   return ToolChain::CST_Libstdcxx;
376 }
377 
378 bool Linux::HasNativeLLVMSupport() const { return true; }
379 
380 Tool *Linux::buildLinker() const { return new tools::gnutools::Linker(*this); }
381 
382 Tool *Linux::buildStaticLibTool() const {
383   return new tools::gnutools::StaticLibTool(*this);
384 }
385 
386 Tool *Linux::buildAssembler() const {
387   return new tools::gnutools::Assembler(*this);
388 }
389 
390 std::string Linux::computeSysRoot() const {
391   if (!getDriver().SysRoot.empty())
392     return getDriver().SysRoot;
393 
394   if (getTriple().isAndroid()) {
395     // Android toolchains typically include a sysroot at ../sysroot relative to
396     // the clang binary.
397     const StringRef ClangDir = getDriver().getInstalledDir();
398     std::string AndroidSysRootPath = (ClangDir + "/../sysroot").str();
399     if (getVFS().exists(AndroidSysRootPath))
400       return AndroidSysRootPath;
401   }
402 
403   if (!GCCInstallation.isValid() || !getTriple().isMIPS())
404     return std::string();
405 
406   // Standalone MIPS toolchains use different names for sysroot folder
407   // and put it into different places. Here we try to check some known
408   // variants.
409 
410   const StringRef InstallDir = GCCInstallation.getInstallPath();
411   const StringRef TripleStr = GCCInstallation.getTriple().str();
412   const Multilib &Multilib = GCCInstallation.getMultilib();
413 
414   std::string Path =
415       (InstallDir + "/../../../../" + TripleStr + "/libc" + Multilib.osSuffix())
416           .str();
417 
418   if (getVFS().exists(Path))
419     return Path;
420 
421   Path = (InstallDir + "/../../../../sysroot" + Multilib.osSuffix()).str();
422 
423   if (getVFS().exists(Path))
424     return Path;
425 
426   return std::string();
427 }
428 
429 std::string Linux::getDynamicLinker(const ArgList &Args) const {
430   const llvm::Triple::ArchType Arch = getArch();
431   const llvm::Triple &Triple = getTriple();
432 
433   const Distro Distro(getDriver().getVFS(), Triple);
434 
435   if (Triple.isAndroid())
436     return Triple.isArch64Bit() ? "/system/bin/linker64" : "/system/bin/linker";
437 
438   if (Triple.isMusl()) {
439     std::string ArchName;
440     bool IsArm = false;
441 
442     switch (Arch) {
443     case llvm::Triple::arm:
444     case llvm::Triple::thumb:
445       ArchName = "arm";
446       IsArm = true;
447       break;
448     case llvm::Triple::armeb:
449     case llvm::Triple::thumbeb:
450       ArchName = "armeb";
451       IsArm = true;
452       break;
453     default:
454       ArchName = Triple.getArchName().str();
455     }
456     if (IsArm &&
457         (Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
458          tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard))
459       ArchName += "hf";
460 
461     return "/lib/ld-musl-" + ArchName + ".so.1";
462   }
463 
464   std::string LibDir;
465   std::string Loader;
466 
467   switch (Arch) {
468   default:
469     llvm_unreachable("unsupported architecture");
470 
471   case llvm::Triple::aarch64:
472     LibDir = "lib";
473     Loader = "ld-linux-aarch64.so.1";
474     break;
475   case llvm::Triple::aarch64_be:
476     LibDir = "lib";
477     Loader = "ld-linux-aarch64_be.so.1";
478     break;
479   case llvm::Triple::arm:
480   case llvm::Triple::thumb:
481   case llvm::Triple::armeb:
482   case llvm::Triple::thumbeb: {
483     const bool HF =
484         Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
485         tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard;
486 
487     LibDir = "lib";
488     Loader = HF ? "ld-linux-armhf.so.3" : "ld-linux.so.3";
489     break;
490   }
491   case llvm::Triple::m68k:
492     LibDir = "lib";
493     Loader = "ld.so.1";
494     break;
495   case llvm::Triple::mips:
496   case llvm::Triple::mipsel:
497   case llvm::Triple::mips64:
498   case llvm::Triple::mips64el: {
499     bool IsNaN2008 = tools::mips::isNaN2008(Args, Triple);
500 
501     LibDir = "lib" + tools::mips::getMipsABILibSuffix(Args, Triple);
502 
503     if (tools::mips::isUCLibc(Args))
504       Loader = IsNaN2008 ? "ld-uClibc-mipsn8.so.0" : "ld-uClibc.so.0";
505     else if (!Triple.hasEnvironment() &&
506              Triple.getVendor() == llvm::Triple::VendorType::MipsTechnologies)
507       Loader =
508           Triple.isLittleEndian() ? "ld-musl-mipsel.so.1" : "ld-musl-mips.so.1";
509     else
510       Loader = IsNaN2008 ? "ld-linux-mipsn8.so.1" : "ld.so.1";
511 
512     break;
513   }
514   case llvm::Triple::ppc:
515     LibDir = "lib";
516     Loader = "ld.so.1";
517     break;
518   case llvm::Triple::ppcle:
519     LibDir = "lib";
520     Loader = "ld.so.1";
521     break;
522   case llvm::Triple::ppc64:
523     LibDir = "lib64";
524     Loader =
525         (tools::ppc::hasPPCAbiArg(Args, "elfv2")) ? "ld64.so.2" : "ld64.so.1";
526     break;
527   case llvm::Triple::ppc64le:
528     LibDir = "lib64";
529     Loader =
530         (tools::ppc::hasPPCAbiArg(Args, "elfv1")) ? "ld64.so.1" : "ld64.so.2";
531     break;
532   case llvm::Triple::riscv32: {
533     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
534     LibDir = "lib";
535     Loader = ("ld-linux-riscv32-" + ABIName + ".so.1").str();
536     break;
537   }
538   case llvm::Triple::riscv64: {
539     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
540     LibDir = "lib";
541     Loader = ("ld-linux-riscv64-" + ABIName + ".so.1").str();
542     break;
543   }
544   case llvm::Triple::sparc:
545   case llvm::Triple::sparcel:
546     LibDir = "lib";
547     Loader = "ld-linux.so.2";
548     break;
549   case llvm::Triple::sparcv9:
550     LibDir = "lib64";
551     Loader = "ld-linux.so.2";
552     break;
553   case llvm::Triple::systemz:
554     LibDir = "lib";
555     Loader = "ld64.so.1";
556     break;
557   case llvm::Triple::x86:
558     LibDir = "lib";
559     Loader = "ld-linux.so.2";
560     break;
561   case llvm::Triple::x86_64: {
562     bool X32 = Triple.getEnvironment() == llvm::Triple::GNUX32;
563 
564     LibDir = X32 ? "libx32" : "lib64";
565     Loader = X32 ? "ld-linux-x32.so.2" : "ld-linux-x86-64.so.2";
566     break;
567   }
568   case llvm::Triple::ve:
569     return "/opt/nec/ve/lib/ld-linux-ve.so.1";
570   }
571 
572   if (Distro == Distro::Exherbo &&
573       (Triple.getVendor() == llvm::Triple::UnknownVendor ||
574        Triple.getVendor() == llvm::Triple::PC))
575     return "/usr/" + Triple.str() + "/lib/" + Loader;
576   return "/" + LibDir + "/" + Loader;
577 }
578 
579 void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
580                                       ArgStringList &CC1Args) const {
581   const Driver &D = getDriver();
582   std::string SysRoot = computeSysRoot();
583 
584   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
585     return;
586 
587   if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
588     addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
589 
590   SmallString<128> ResourceDirInclude(D.ResourceDir);
591   llvm::sys::path::append(ResourceDirInclude, "include");
592   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) &&
593       (!getTriple().isMusl() || DriverArgs.hasArg(options::OPT_nostdlibinc)))
594     addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
595 
596   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
597     return;
598 
599   // Check for configure-time C include directories.
600   StringRef CIncludeDirs(C_INCLUDE_DIRS);
601   if (CIncludeDirs != "") {
602     SmallVector<StringRef, 5> dirs;
603     CIncludeDirs.split(dirs, ":");
604     for (StringRef dir : dirs) {
605       StringRef Prefix =
606           llvm::sys::path::is_absolute(dir) ? "" : StringRef(SysRoot);
607       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
608     }
609     return;
610   }
611 
612   // Lacking those, try to detect the correct set of system includes for the
613   // target triple.
614 
615   AddMultilibIncludeArgs(DriverArgs, CC1Args);
616 
617   // Implement generic Debian multiarch support.
618   const StringRef X86_64MultiarchIncludeDirs[] = {
619       "/usr/include/x86_64-linux-gnu",
620 
621       // FIXME: These are older forms of multiarch. It's not clear that they're
622       // in use in any released version of Debian, so we should consider
623       // removing them.
624       "/usr/include/i686-linux-gnu/64", "/usr/include/i486-linux-gnu/64"};
625   const StringRef X86MultiarchIncludeDirs[] = {
626       "/usr/include/i386-linux-gnu",
627 
628       // FIXME: These are older forms of multiarch. It's not clear that they're
629       // in use in any released version of Debian, so we should consider
630       // removing them.
631       "/usr/include/x86_64-linux-gnu/32", "/usr/include/i686-linux-gnu",
632       "/usr/include/i486-linux-gnu"};
633   const StringRef AArch64MultiarchIncludeDirs[] = {
634       "/usr/include/aarch64-linux-gnu"};
635   const StringRef ARMMultiarchIncludeDirs[] = {
636       "/usr/include/arm-linux-gnueabi"};
637   const StringRef ARMHFMultiarchIncludeDirs[] = {
638       "/usr/include/arm-linux-gnueabihf"};
639   const StringRef ARMEBMultiarchIncludeDirs[] = {
640       "/usr/include/armeb-linux-gnueabi"};
641   const StringRef ARMEBHFMultiarchIncludeDirs[] = {
642       "/usr/include/armeb-linux-gnueabihf"};
643   const StringRef M68kMultiarchIncludeDirs[] = {"/usr/include/m68k-linux-gnu"};
644   const StringRef MIPSMultiarchIncludeDirs[] = {"/usr/include/mips-linux-gnu"};
645   const StringRef MIPSELMultiarchIncludeDirs[] = {
646       "/usr/include/mipsel-linux-gnu"};
647   const StringRef MIPS64MultiarchIncludeDirs[] = {
648       "/usr/include/mips64-linux-gnuabi64"};
649   const StringRef MIPS64ELMultiarchIncludeDirs[] = {
650       "/usr/include/mips64el-linux-gnuabi64"};
651   const StringRef MIPSN32MultiarchIncludeDirs[] = {
652       "/usr/include/mips64-linux-gnuabin32"};
653   const StringRef MIPSN32ELMultiarchIncludeDirs[] = {
654       "/usr/include/mips64el-linux-gnuabin32"};
655   const StringRef MIPSR6MultiarchIncludeDirs[] = {
656       "/usr/include/mipsisa32-linux-gnu"};
657   const StringRef MIPSR6ELMultiarchIncludeDirs[] = {
658       "/usr/include/mipsisa32r6el-linux-gnu"};
659   const StringRef MIPS64R6MultiarchIncludeDirs[] = {
660       "/usr/include/mipsisa64r6-linux-gnuabi64"};
661   const StringRef MIPS64R6ELMultiarchIncludeDirs[] = {
662       "/usr/include/mipsisa64r6el-linux-gnuabi64"};
663   const StringRef MIPSN32R6MultiarchIncludeDirs[] = {
664       "/usr/include/mipsisa64r6-linux-gnuabin32"};
665   const StringRef MIPSN32R6ELMultiarchIncludeDirs[] = {
666       "/usr/include/mipsisa64r6el-linux-gnuabin32"};
667   const StringRef PPCMultiarchIncludeDirs[] = {
668       "/usr/include/powerpc-linux-gnu",
669       "/usr/include/powerpc-linux-gnuspe"};
670   const StringRef PPCLEMultiarchIncludeDirs[] = {
671       "/usr/include/powerpcle-linux-gnu"};
672   const StringRef PPC64MultiarchIncludeDirs[] = {
673       "/usr/include/powerpc64-linux-gnu"};
674   const StringRef PPC64LEMultiarchIncludeDirs[] = {
675       "/usr/include/powerpc64le-linux-gnu"};
676   const StringRef SparcMultiarchIncludeDirs[] = {
677       "/usr/include/sparc-linux-gnu"};
678   const StringRef Sparc64MultiarchIncludeDirs[] = {
679       "/usr/include/sparc64-linux-gnu"};
680   const StringRef SYSTEMZMultiarchIncludeDirs[] = {
681       "/usr/include/s390x-linux-gnu"};
682   ArrayRef<StringRef> MultiarchIncludeDirs;
683   switch (getTriple().getArch()) {
684   case llvm::Triple::x86_64:
685     MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
686     break;
687   case llvm::Triple::x86:
688     MultiarchIncludeDirs = X86MultiarchIncludeDirs;
689     break;
690   case llvm::Triple::aarch64:
691   case llvm::Triple::aarch64_be:
692     MultiarchIncludeDirs = AArch64MultiarchIncludeDirs;
693     break;
694   case llvm::Triple::arm:
695   case llvm::Triple::thumb:
696     if (getTriple().getEnvironment() == llvm::Triple::GNUEABIHF)
697       MultiarchIncludeDirs = ARMHFMultiarchIncludeDirs;
698     else
699       MultiarchIncludeDirs = ARMMultiarchIncludeDirs;
700     break;
701   case llvm::Triple::armeb:
702   case llvm::Triple::thumbeb:
703     if (getTriple().getEnvironment() == llvm::Triple::GNUEABIHF)
704       MultiarchIncludeDirs = ARMEBHFMultiarchIncludeDirs;
705     else
706       MultiarchIncludeDirs = ARMEBMultiarchIncludeDirs;
707     break;
708   case llvm::Triple::m68k:
709     MultiarchIncludeDirs = M68kMultiarchIncludeDirs;
710     break;
711   case llvm::Triple::mips:
712     if (getTriple().getSubArch() == llvm::Triple::MipsSubArch_r6)
713       MultiarchIncludeDirs = MIPSR6MultiarchIncludeDirs;
714     else
715       MultiarchIncludeDirs = MIPSMultiarchIncludeDirs;
716     break;
717   case llvm::Triple::mipsel:
718     if (getTriple().getSubArch() == llvm::Triple::MipsSubArch_r6)
719       MultiarchIncludeDirs = MIPSR6ELMultiarchIncludeDirs;
720     else
721       MultiarchIncludeDirs = MIPSELMultiarchIncludeDirs;
722     break;
723   case llvm::Triple::mips64:
724     if (getTriple().getSubArch() == llvm::Triple::MipsSubArch_r6)
725       if (getTriple().getEnvironment() == llvm::Triple::GNUABIN32)
726         MultiarchIncludeDirs = MIPSN32R6MultiarchIncludeDirs;
727       else
728         MultiarchIncludeDirs = MIPS64R6MultiarchIncludeDirs;
729     else if (getTriple().getEnvironment() == llvm::Triple::GNUABIN32)
730       MultiarchIncludeDirs = MIPSN32MultiarchIncludeDirs;
731     else
732       MultiarchIncludeDirs = MIPS64MultiarchIncludeDirs;
733     break;
734   case llvm::Triple::mips64el:
735     if (getTriple().getSubArch() == llvm::Triple::MipsSubArch_r6)
736       if (getTriple().getEnvironment() == llvm::Triple::GNUABIN32)
737         MultiarchIncludeDirs = MIPSN32R6ELMultiarchIncludeDirs;
738       else
739         MultiarchIncludeDirs = MIPS64R6ELMultiarchIncludeDirs;
740     else if (getTriple().getEnvironment() == llvm::Triple::GNUABIN32)
741       MultiarchIncludeDirs = MIPSN32ELMultiarchIncludeDirs;
742     else
743       MultiarchIncludeDirs = MIPS64ELMultiarchIncludeDirs;
744     break;
745   case llvm::Triple::ppc:
746     MultiarchIncludeDirs = PPCMultiarchIncludeDirs;
747     break;
748   case llvm::Triple::ppcle:
749     MultiarchIncludeDirs = PPCLEMultiarchIncludeDirs;
750     break;
751   case llvm::Triple::ppc64:
752     MultiarchIncludeDirs = PPC64MultiarchIncludeDirs;
753     break;
754   case llvm::Triple::ppc64le:
755     MultiarchIncludeDirs = PPC64LEMultiarchIncludeDirs;
756     break;
757   case llvm::Triple::sparc:
758     MultiarchIncludeDirs = SparcMultiarchIncludeDirs;
759     break;
760   case llvm::Triple::sparcv9:
761     MultiarchIncludeDirs = Sparc64MultiarchIncludeDirs;
762     break;
763   case llvm::Triple::systemz:
764     MultiarchIncludeDirs = SYSTEMZMultiarchIncludeDirs;
765     break;
766   default:
767     break;
768   }
769 
770   const std::string AndroidMultiarchIncludeDir =
771       std::string("/usr/include/") +
772       getMultiarchTriple(D, getTriple(), SysRoot);
773   const StringRef AndroidMultiarchIncludeDirs[] = {AndroidMultiarchIncludeDir};
774   if (getTriple().isAndroid())
775     MultiarchIncludeDirs = AndroidMultiarchIncludeDirs;
776 
777   for (StringRef Dir : MultiarchIncludeDirs) {
778     if (D.getVFS().exists(SysRoot + Dir)) {
779       addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + Dir);
780       break;
781     }
782   }
783 
784   if (getTriple().getOS() == llvm::Triple::RTEMS)
785     return;
786 
787   // Add an include of '/include' directly. This isn't provided by default by
788   // system GCCs, but is often used with cross-compiling GCCs, and harmless to
789   // add even when Clang is acting as-if it were a system compiler.
790   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
791 
792   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
793 
794   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && getTriple().isMusl())
795     addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
796 }
797 
798 void Linux::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
799                                      llvm::opt::ArgStringList &CC1Args) const {
800   // Try generic GCC detection first.
801   if (Generic_GCC::addGCCLibStdCxxIncludePaths(DriverArgs, CC1Args))
802     return;
803 
804   // We need a detected GCC installation on Linux to provide libstdc++'s
805   // headers in odd Linuxish places.
806   if (!GCCInstallation.isValid())
807     return;
808 
809   StringRef LibDir = GCCInstallation.getParentLibPath();
810   StringRef TripleStr = GCCInstallation.getTriple().str();
811   const Multilib &Multilib = GCCInstallation.getMultilib();
812   const GCCVersion &Version = GCCInstallation.getVersion();
813 
814   const std::string LibStdCXXIncludePathCandidates[] = {
815       // Android standalone toolchain has C++ headers in yet another place.
816       LibDir.str() + "/../" + TripleStr.str() + "/include/c++/" + Version.Text,
817       // Freescale SDK C++ headers are directly in <sysroot>/usr/include/c++,
818       // without a subdirectory corresponding to the gcc version.
819       LibDir.str() + "/../include/c++",
820       // Cray's gcc installation puts headers under "g++" without a
821       // version suffix.
822       LibDir.str() + "/../include/g++",
823   };
824 
825   for (const auto &IncludePath : LibStdCXXIncludePathCandidates) {
826     if (addLibStdCXXIncludePaths(IncludePath, /*Suffix*/ "", TripleStr,
827                                  /*GCCMultiarchTriple*/ "",
828                                  /*TargetMultiarchTriple*/ "",
829                                  Multilib.includeSuffix(), DriverArgs, CC1Args))
830       break;
831   }
832 }
833 
834 void Linux::AddCudaIncludeArgs(const ArgList &DriverArgs,
835                                ArgStringList &CC1Args) const {
836   CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
837 }
838 
839 void Linux::AddHIPIncludeArgs(const ArgList &DriverArgs,
840                               ArgStringList &CC1Args) const {
841   RocmInstallation.AddHIPIncludeArgs(DriverArgs, CC1Args);
842 }
843 
844 void Linux::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
845                                 ArgStringList &CC1Args) const {
846   if (GCCInstallation.isValid()) {
847     CC1Args.push_back("-isystem");
848     CC1Args.push_back(DriverArgs.MakeArgString(
849         GCCInstallation.getParentLibPath() + "/../" +
850         GCCInstallation.getTriple().str() + "/include"));
851   }
852 }
853 
854 bool Linux::isPIEDefault() const {
855   return (getTriple().isAndroid() && !getTriple().isAndroidVersionLT(16)) ||
856           getTriple().isMusl() || getSanitizerArgs().requiresPIE();
857 }
858 
859 bool Linux::IsAArch64OutlineAtomicsDefault(const ArgList &Args) const {
860   // Outline atomics for AArch64 are supported by compiler-rt
861   // and libgcc since 9.3.1
862   assert(getTriple().isAArch64() && "expected AArch64 target!");
863   ToolChain::RuntimeLibType RtLib = GetRuntimeLibType(Args);
864   if (RtLib == ToolChain::RLT_CompilerRT)
865     return true;
866   assert(RtLib == ToolChain::RLT_Libgcc && "unexpected runtime library type!");
867   if (GCCInstallation.getVersion().isOlderThan(9, 3, 1))
868     return false;
869   return true;
870 }
871 
872 bool Linux::isNoExecStackDefault() const {
873     return getTriple().isAndroid();
874 }
875 
876 bool Linux::IsMathErrnoDefault() const {
877   if (getTriple().isAndroid())
878     return false;
879   return Generic_ELF::IsMathErrnoDefault();
880 }
881 
882 SanitizerMask Linux::getSupportedSanitizers() const {
883   const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
884   const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
885   const bool IsMIPS = getTriple().isMIPS32();
886   const bool IsMIPS64 = getTriple().isMIPS64();
887   const bool IsPowerPC64 = getTriple().getArch() == llvm::Triple::ppc64 ||
888                            getTriple().getArch() == llvm::Triple::ppc64le;
889   const bool IsAArch64 = getTriple().getArch() == llvm::Triple::aarch64 ||
890                          getTriple().getArch() == llvm::Triple::aarch64_be;
891   const bool IsArmArch = getTriple().getArch() == llvm::Triple::arm ||
892                          getTriple().getArch() == llvm::Triple::thumb ||
893                          getTriple().getArch() == llvm::Triple::armeb ||
894                          getTriple().getArch() == llvm::Triple::thumbeb;
895   const bool IsRISCV64 = getTriple().getArch() == llvm::Triple::riscv64;
896   const bool IsSystemZ = getTriple().getArch() == llvm::Triple::systemz;
897   SanitizerMask Res = ToolChain::getSupportedSanitizers();
898   Res |= SanitizerKind::Address;
899   Res |= SanitizerKind::PointerCompare;
900   Res |= SanitizerKind::PointerSubtract;
901   Res |= SanitizerKind::Fuzzer;
902   Res |= SanitizerKind::FuzzerNoLink;
903   Res |= SanitizerKind::KernelAddress;
904   Res |= SanitizerKind::Memory;
905   Res |= SanitizerKind::Vptr;
906   Res |= SanitizerKind::SafeStack;
907   if (IsX86_64 || IsMIPS64 || IsAArch64)
908     Res |= SanitizerKind::DataFlow;
909   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsX86 || IsArmArch || IsPowerPC64 ||
910       IsRISCV64 || IsSystemZ)
911     Res |= SanitizerKind::Leak;
912   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsPowerPC64)
913     Res |= SanitizerKind::Thread;
914   if (IsX86_64)
915     Res |= SanitizerKind::KernelMemory;
916   if (IsX86 || IsX86_64)
917     Res |= SanitizerKind::Function;
918   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsX86 || IsMIPS || IsArmArch ||
919       IsPowerPC64)
920     Res |= SanitizerKind::Scudo;
921   if (IsX86_64 || IsAArch64) {
922     Res |= SanitizerKind::HWAddress;
923     Res |= SanitizerKind::KernelHWAddress;
924   }
925   return Res;
926 }
927 
928 void Linux::addProfileRTLibs(const llvm::opt::ArgList &Args,
929                              llvm::opt::ArgStringList &CmdArgs) const {
930   // Add linker option -u__llvm_profile_runtime to cause runtime
931   // initialization module to be linked in.
932   if (needsProfileRT(Args))
933     CmdArgs.push_back(Args.MakeArgString(
934         Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
935   ToolChain::addProfileRTLibs(Args, CmdArgs);
936 }
937 
938 llvm::DenormalMode
939 Linux::getDefaultDenormalModeForType(const llvm::opt::ArgList &DriverArgs,
940                                      const JobAction &JA,
941                                      const llvm::fltSemantics *FPType) const {
942   switch (getTriple().getArch()) {
943   case llvm::Triple::x86:
944   case llvm::Triple::x86_64: {
945     std::string Unused;
946     // DAZ and FTZ are turned on in crtfastmath.o
947     if (!DriverArgs.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles) &&
948         isFastMathRuntimeAvailable(DriverArgs, Unused))
949       return llvm::DenormalMode::getPreserveSign();
950     return llvm::DenormalMode::getIEEE();
951   }
952   default:
953     return llvm::DenormalMode::getIEEE();
954   }
955 }
956 
957 void Linux::addExtraOpts(llvm::opt::ArgStringList &CmdArgs) const {
958   for (const auto &Opt : ExtraOpts)
959     CmdArgs.push_back(Opt.c_str());
960 }
961