xref: /freebsd/contrib/llvm-project/clang/lib/Driver/ToolChains/Linux.cpp (revision 62ff619dcc3540659a319be71c9a489f1659e14a)
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     if (TargetEnvironment == llvm::Triple::GNUEABIHF)
64       return "arm-linux-gnueabihf";
65     return "arm-linux-gnueabi";
66   case llvm::Triple::armeb:
67   case llvm::Triple::thumbeb:
68     if (TargetEnvironment == llvm::Triple::GNUEABIHF)
69       return "armeb-linux-gnueabihf";
70     return "armeb-linux-gnueabi";
71   case llvm::Triple::x86:
72     if (IsAndroid)
73       return "i686-linux-android";
74     return "i386-linux-gnu";
75   case llvm::Triple::x86_64:
76     if (IsAndroid)
77       return "x86_64-linux-android";
78     if (TargetEnvironment == llvm::Triple::GNUX32)
79       return "x86_64-linux-gnux32";
80     return "x86_64-linux-gnu";
81   case llvm::Triple::aarch64:
82     if (IsAndroid)
83       return "aarch64-linux-android";
84     return "aarch64-linux-gnu";
85   case llvm::Triple::aarch64_be:
86     return "aarch64_be-linux-gnu";
87 
88   case llvm::Triple::m68k:
89     return "m68k-linux-gnu";
90 
91   case llvm::Triple::mips:
92     return IsMipsR6 ? "mipsisa32r6-linux-gnu" : "mips-linux-gnu";
93   case llvm::Triple::mipsel:
94     if (IsAndroid)
95       return "mipsel-linux-android";
96     return IsMipsR6 ? "mipsisa32r6el-linux-gnu" : "mipsel-linux-gnu";
97   case llvm::Triple::mips64: {
98     std::string MT = std::string(IsMipsR6 ? "mipsisa64r6" : "mips64") +
99                      "-linux-" + (IsMipsN32Abi ? "gnuabin32" : "gnuabi64");
100     if (D.getVFS().exists(SysRoot + "/lib/" + MT))
101       return MT;
102     if (D.getVFS().exists(SysRoot + "/lib/mips64-linux-gnu"))
103       return "mips64-linux-gnu";
104     break;
105   }
106   case llvm::Triple::mips64el: {
107     if (IsAndroid)
108       return "mips64el-linux-android";
109     std::string MT = std::string(IsMipsR6 ? "mipsisa64r6el" : "mips64el") +
110                      "-linux-" + (IsMipsN32Abi ? "gnuabin32" : "gnuabi64");
111     if (D.getVFS().exists(SysRoot + "/lib/" + MT))
112       return MT;
113     if (D.getVFS().exists(SysRoot + "/lib/mips64el-linux-gnu"))
114       return "mips64el-linux-gnu";
115     break;
116   }
117   case llvm::Triple::ppc:
118     if (D.getVFS().exists(SysRoot + "/lib/powerpc-linux-gnuspe"))
119       return "powerpc-linux-gnuspe";
120     return "powerpc-linux-gnu";
121   case llvm::Triple::ppcle:
122     return "powerpcle-linux-gnu";
123   case llvm::Triple::ppc64:
124     return "powerpc64-linux-gnu";
125   case llvm::Triple::ppc64le:
126     return "powerpc64le-linux-gnu";
127   case llvm::Triple::sparc:
128     return "sparc-linux-gnu";
129   case llvm::Triple::sparcv9:
130     return "sparc64-linux-gnu";
131   case llvm::Triple::systemz:
132     return "s390x-linux-gnu";
133   }
134   return TargetTriple.str();
135 }
136 
137 static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {
138   if (Triple.isMIPS()) {
139     if (Triple.isAndroid()) {
140       StringRef CPUName;
141       StringRef ABIName;
142       tools::mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
143       if (CPUName == "mips32r6")
144         return "libr6";
145       if (CPUName == "mips32r2")
146         return "libr2";
147     }
148     // lib32 directory has a special meaning on MIPS targets.
149     // It contains N32 ABI binaries. Use this folder if produce
150     // code for N32 ABI only.
151     if (tools::mips::hasMipsAbiArg(Args, "n32"))
152       return "lib32";
153     return Triple.isArch32Bit() ? "lib" : "lib64";
154   }
155 
156   // It happens that only x86, PPC and SPARC use the 'lib32' variant of
157   // oslibdir, and using that variant while targeting other architectures causes
158   // problems because the libraries are laid out in shared system roots that
159   // can't cope with a 'lib32' library search path being considered. So we only
160   // enable them when we know we may need it.
161   //
162   // FIXME: This is a bit of a hack. We should really unify this code for
163   // reasoning about oslibdir spellings with the lib dir spellings in the
164   // GCCInstallationDetector, but that is a more significant refactoring.
165   if (Triple.getArch() == llvm::Triple::x86 || Triple.isPPC32() ||
166       Triple.getArch() == llvm::Triple::sparc)
167     return "lib32";
168 
169   if (Triple.getArch() == llvm::Triple::x86_64 && Triple.isX32())
170     return "libx32";
171 
172   if (Triple.getArch() == llvm::Triple::riscv32)
173     return "lib32";
174 
175   return Triple.isArch32Bit() ? "lib" : "lib64";
176 }
177 
178 Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
179     : Generic_ELF(D, Triple, Args) {
180   GCCInstallation.init(Triple, Args);
181   Multilibs = GCCInstallation.getMultilibs();
182   SelectedMultilib = GCCInstallation.getMultilib();
183   llvm::Triple::ArchType Arch = Triple.getArch();
184   std::string SysRoot = computeSysRoot();
185   ToolChain::path_list &PPaths = getProgramPaths();
186 
187   Generic_GCC::PushPPaths(PPaths);
188 
189   Distro Distro(D.getVFS(), Triple);
190 
191   if (Distro.IsAlpineLinux() || Triple.isAndroid()) {
192     ExtraOpts.push_back("-z");
193     ExtraOpts.push_back("now");
194   }
195 
196   if (Distro.IsOpenSUSE() || Distro.IsUbuntu() || Distro.IsAlpineLinux() ||
197       Triple.isAndroid()) {
198     ExtraOpts.push_back("-z");
199     ExtraOpts.push_back("relro");
200   }
201 
202   // Android ARM/AArch64 use max-page-size=4096 to reduce VMA usage. Note, lld
203   // from 11 onwards default max-page-size to 65536 for both ARM and AArch64.
204   if ((Triple.isARM() || Triple.isAArch64()) && Triple.isAndroid()) {
205     ExtraOpts.push_back("-z");
206     ExtraOpts.push_back("max-page-size=4096");
207   }
208 
209   if (GCCInstallation.getParentLibPath().contains("opt/rh/"))
210     // With devtoolset on RHEL, we want to add a bin directory that is relative
211     // to the detected gcc install, because if we are using devtoolset gcc then
212     // we want to use other tools from devtoolset (e.g. ld) instead of the
213     // standard system tools.
214     PPaths.push_back(Twine(GCCInstallation.getParentLibPath() +
215                      "/../bin").str());
216 
217   if (Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb)
218     ExtraOpts.push_back("-X");
219 
220   const bool IsAndroid = Triple.isAndroid();
221   const bool IsMips = Triple.isMIPS();
222   const bool IsHexagon = Arch == llvm::Triple::hexagon;
223   const bool IsRISCV = Triple.isRISCV();
224 
225   if (IsMips && !SysRoot.empty())
226     ExtraOpts.push_back("--sysroot=" + SysRoot);
227 
228   // Do not use 'gnu' hash style for Mips targets because .gnu.hash
229   // and the MIPS ABI require .dynsym to be sorted in different ways.
230   // .gnu.hash needs symbols to be grouped by hash code whereas the MIPS
231   // ABI requires a mapping between the GOT and the symbol table.
232   // Android loader does not support .gnu.hash until API 23.
233   // Hexagon linker/loader does not support .gnu.hash
234   if (!IsMips && !IsHexagon) {
235     if (Distro.IsRedhat() || Distro.IsOpenSUSE() || Distro.IsAlpineLinux() ||
236         (Distro.IsUbuntu() && Distro >= Distro::UbuntuMaverick) ||
237         (IsAndroid && !Triple.isAndroidVersionLT(23)))
238       ExtraOpts.push_back("--hash-style=gnu");
239 
240     if (Distro.IsDebian() || Distro.IsOpenSUSE() ||
241         Distro == Distro::UbuntuLucid || Distro == Distro::UbuntuJaunty ||
242         Distro == Distro::UbuntuKarmic ||
243         (IsAndroid && Triple.isAndroidVersionLT(23)))
244       ExtraOpts.push_back("--hash-style=both");
245   }
246 
247 #ifdef ENABLE_LINKER_BUILD_ID
248   ExtraOpts.push_back("--build-id");
249 #endif
250 
251   if (IsAndroid || Distro.IsOpenSUSE())
252     ExtraOpts.push_back("--enable-new-dtags");
253 
254   // The selection of paths to try here is designed to match the patterns which
255   // the GCC driver itself uses, as this is part of the GCC-compatible driver.
256   // This was determined by running GCC in a fake filesystem, creating all
257   // possible permutations of these directories, and seeing which ones it added
258   // to the link paths.
259   path_list &Paths = getFilePaths();
260 
261   const std::string OSLibDir = std::string(getOSLibDir(Triple, Args));
262   const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);
263 
264   // mips32: Debian multilib, we use /libo32, while in other case, /lib is
265   // used. We need add both libo32 and /lib.
266   if (Arch == llvm::Triple::mips || Arch == llvm::Triple::mipsel) {
267     Generic_GCC::AddMultilibPaths(D, SysRoot, "libo32", MultiarchTriple, Paths);
268     addPathIfExists(D, SysRoot + "/libo32", Paths);
269     addPathIfExists(D, SysRoot + "/usr/libo32", Paths);
270   }
271   Generic_GCC::AddMultilibPaths(D, SysRoot, OSLibDir, MultiarchTriple, Paths);
272 
273   addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
274   addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
275 
276   if (IsAndroid) {
277     // Android sysroots contain a library directory for each supported OS
278     // version as well as some unversioned libraries in the usual multiarch
279     // directory.
280     addPathIfExists(
281         D,
282         SysRoot + "/usr/lib/" + MultiarchTriple + "/" +
283             llvm::to_string(Triple.getEnvironmentVersion().getMajor()),
284         Paths);
285   }
286 
287   addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
288   // 64-bit OpenEmbedded sysroots may not have a /usr/lib dir. So they cannot
289   // find /usr/lib64 as it is referenced as /usr/lib/../lib64. So we handle
290   // this here.
291   if (Triple.getVendor() == llvm::Triple::OpenEmbedded &&
292       Triple.isArch64Bit())
293     addPathIfExists(D, SysRoot + "/usr/" + OSLibDir, Paths);
294   else
295     addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
296   if (IsRISCV) {
297     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
298     addPathIfExists(D, SysRoot + "/" + OSLibDir + "/" + ABIName, Paths);
299     addPathIfExists(D, SysRoot + "/usr/" + OSLibDir + "/" + ABIName, Paths);
300   }
301 
302   Generic_GCC::AddMultiarchPaths(D, SysRoot, OSLibDir, Paths);
303 
304   // Similar to the logic for GCC above, if we are currently running Clang
305   // inside of the requested system root, add its parent library path to those
306   // searched.
307   // FIXME: It's not clear whether we should use the driver's installed
308   // directory ('Dir' below) or the ResourceDir.
309   if (StringRef(D.Dir).startswith(SysRoot)) {
310     // Even if OSLibDir != "lib", this is needed for Clang in the build
311     // directory (not installed) to find libc++.
312     addPathIfExists(D, D.Dir + "/../lib", Paths);
313     if (OSLibDir != "lib")
314       addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
315   }
316 
317   addPathIfExists(D, SysRoot + "/lib", Paths);
318   addPathIfExists(D, SysRoot + "/usr/lib", Paths);
319 }
320 
321 ToolChain::RuntimeLibType Linux::GetDefaultRuntimeLibType() const {
322   if (getTriple().isAndroid())
323     return ToolChain::RLT_CompilerRT;
324   return Generic_ELF::GetDefaultRuntimeLibType();
325 }
326 
327 unsigned Linux::GetDefaultDwarfVersion() const {
328   if (getTriple().isAndroid())
329     return 4;
330   return ToolChain::GetDefaultDwarfVersion();
331 }
332 
333 ToolChain::CXXStdlibType Linux::GetDefaultCXXStdlibType() const {
334   if (getTriple().isAndroid())
335     return ToolChain::CST_Libcxx;
336   return ToolChain::CST_Libstdcxx;
337 }
338 
339 bool Linux::HasNativeLLVMSupport() const { return true; }
340 
341 Tool *Linux::buildLinker() const { return new tools::gnutools::Linker(*this); }
342 
343 Tool *Linux::buildStaticLibTool() const {
344   return new tools::gnutools::StaticLibTool(*this);
345 }
346 
347 Tool *Linux::buildAssembler() const {
348   return new tools::gnutools::Assembler(*this);
349 }
350 
351 std::string Linux::computeSysRoot() const {
352   if (!getDriver().SysRoot.empty())
353     return getDriver().SysRoot;
354 
355   if (getTriple().isAndroid()) {
356     // Android toolchains typically include a sysroot at ../sysroot relative to
357     // the clang binary.
358     const StringRef ClangDir = getDriver().getInstalledDir();
359     std::string AndroidSysRootPath = (ClangDir + "/../sysroot").str();
360     if (getVFS().exists(AndroidSysRootPath))
361       return AndroidSysRootPath;
362   }
363 
364   if (!GCCInstallation.isValid() || !getTriple().isMIPS())
365     return std::string();
366 
367   // Standalone MIPS toolchains use different names for sysroot folder
368   // and put it into different places. Here we try to check some known
369   // variants.
370 
371   const StringRef InstallDir = GCCInstallation.getInstallPath();
372   const StringRef TripleStr = GCCInstallation.getTriple().str();
373   const Multilib &Multilib = GCCInstallation.getMultilib();
374 
375   std::string Path =
376       (InstallDir + "/../../../../" + TripleStr + "/libc" + Multilib.osSuffix())
377           .str();
378 
379   if (getVFS().exists(Path))
380     return Path;
381 
382   Path = (InstallDir + "/../../../../sysroot" + Multilib.osSuffix()).str();
383 
384   if (getVFS().exists(Path))
385     return Path;
386 
387   return std::string();
388 }
389 
390 std::string Linux::getDynamicLinker(const ArgList &Args) const {
391   const llvm::Triple::ArchType Arch = getArch();
392   const llvm::Triple &Triple = getTriple();
393 
394   const Distro Distro(getDriver().getVFS(), Triple);
395 
396   if (Triple.isAndroid())
397     return Triple.isArch64Bit() ? "/system/bin/linker64" : "/system/bin/linker";
398 
399   if (Triple.isMusl()) {
400     std::string ArchName;
401     bool IsArm = false;
402 
403     switch (Arch) {
404     case llvm::Triple::arm:
405     case llvm::Triple::thumb:
406       ArchName = "arm";
407       IsArm = true;
408       break;
409     case llvm::Triple::armeb:
410     case llvm::Triple::thumbeb:
411       ArchName = "armeb";
412       IsArm = true;
413       break;
414     case llvm::Triple::x86:
415       ArchName = "i386";
416       break;
417     case llvm::Triple::x86_64:
418       ArchName = Triple.isX32() ? "x32" : Triple.getArchName().str();
419       break;
420     default:
421       ArchName = Triple.getArchName().str();
422     }
423     if (IsArm &&
424         (Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
425          tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard))
426       ArchName += "hf";
427     if (Arch == llvm::Triple::ppc &&
428         Triple.getSubArch() == llvm::Triple::PPCSubArch_spe)
429       ArchName = "powerpc-sf";
430 
431     return "/lib/ld-musl-" + ArchName + ".so.1";
432   }
433 
434   std::string LibDir;
435   std::string Loader;
436 
437   switch (Arch) {
438   default:
439     llvm_unreachable("unsupported architecture");
440 
441   case llvm::Triple::aarch64:
442     LibDir = "lib";
443     Loader = "ld-linux-aarch64.so.1";
444     break;
445   case llvm::Triple::aarch64_be:
446     LibDir = "lib";
447     Loader = "ld-linux-aarch64_be.so.1";
448     break;
449   case llvm::Triple::arm:
450   case llvm::Triple::thumb:
451   case llvm::Triple::armeb:
452   case llvm::Triple::thumbeb: {
453     const bool HF =
454         Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
455         tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard;
456 
457     LibDir = "lib";
458     Loader = HF ? "ld-linux-armhf.so.3" : "ld-linux.so.3";
459     break;
460   }
461   case llvm::Triple::m68k:
462     LibDir = "lib";
463     Loader = "ld.so.1";
464     break;
465   case llvm::Triple::mips:
466   case llvm::Triple::mipsel:
467   case llvm::Triple::mips64:
468   case llvm::Triple::mips64el: {
469     bool IsNaN2008 = tools::mips::isNaN2008(getDriver(), Args, Triple);
470 
471     LibDir = "lib" + tools::mips::getMipsABILibSuffix(Args, Triple);
472 
473     if (tools::mips::isUCLibc(Args))
474       Loader = IsNaN2008 ? "ld-uClibc-mipsn8.so.0" : "ld-uClibc.so.0";
475     else if (!Triple.hasEnvironment() &&
476              Triple.getVendor() == llvm::Triple::VendorType::MipsTechnologies)
477       Loader =
478           Triple.isLittleEndian() ? "ld-musl-mipsel.so.1" : "ld-musl-mips.so.1";
479     else
480       Loader = IsNaN2008 ? "ld-linux-mipsn8.so.1" : "ld.so.1";
481 
482     break;
483   }
484   case llvm::Triple::ppc:
485     LibDir = "lib";
486     Loader = "ld.so.1";
487     break;
488   case llvm::Triple::ppcle:
489     LibDir = "lib";
490     Loader = "ld.so.1";
491     break;
492   case llvm::Triple::ppc64:
493     LibDir = "lib64";
494     Loader =
495         (tools::ppc::hasPPCAbiArg(Args, "elfv2")) ? "ld64.so.2" : "ld64.so.1";
496     break;
497   case llvm::Triple::ppc64le:
498     LibDir = "lib64";
499     Loader =
500         (tools::ppc::hasPPCAbiArg(Args, "elfv1")) ? "ld64.so.1" : "ld64.so.2";
501     break;
502   case llvm::Triple::riscv32: {
503     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
504     LibDir = "lib";
505     Loader = ("ld-linux-riscv32-" + ABIName + ".so.1").str();
506     break;
507   }
508   case llvm::Triple::riscv64: {
509     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
510     LibDir = "lib";
511     Loader = ("ld-linux-riscv64-" + ABIName + ".so.1").str();
512     break;
513   }
514   case llvm::Triple::sparc:
515   case llvm::Triple::sparcel:
516     LibDir = "lib";
517     Loader = "ld-linux.so.2";
518     break;
519   case llvm::Triple::sparcv9:
520     LibDir = "lib64";
521     Loader = "ld-linux.so.2";
522     break;
523   case llvm::Triple::systemz:
524     LibDir = "lib";
525     Loader = "ld64.so.1";
526     break;
527   case llvm::Triple::x86:
528     LibDir = "lib";
529     Loader = "ld-linux.so.2";
530     break;
531   case llvm::Triple::x86_64: {
532     bool X32 = Triple.isX32();
533 
534     LibDir = X32 ? "libx32" : "lib64";
535     Loader = X32 ? "ld-linux-x32.so.2" : "ld-linux-x86-64.so.2";
536     break;
537   }
538   case llvm::Triple::ve:
539     return "/opt/nec/ve/lib/ld-linux-ve.so.1";
540   }
541 
542   if (Distro == Distro::Exherbo &&
543       (Triple.getVendor() == llvm::Triple::UnknownVendor ||
544        Triple.getVendor() == llvm::Triple::PC))
545     return "/usr/" + Triple.str() + "/lib/" + Loader;
546   return "/" + LibDir + "/" + Loader;
547 }
548 
549 void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
550                                       ArgStringList &CC1Args) const {
551   const Driver &D = getDriver();
552   std::string SysRoot = computeSysRoot();
553 
554   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
555     return;
556 
557   // Add 'include' in the resource directory, which is similar to
558   // GCC_INCLUDE_DIR (private headers) in GCC. Note: the include directory
559   // contains some files conflicting with system /usr/include. musl systems
560   // prefer the /usr/include copies which are more relevant.
561   SmallString<128> ResourceDirInclude(D.ResourceDir);
562   llvm::sys::path::append(ResourceDirInclude, "include");
563   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) &&
564       (!getTriple().isMusl() || DriverArgs.hasArg(options::OPT_nostdlibinc)))
565     addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
566 
567   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
568     return;
569 
570   // LOCAL_INCLUDE_DIR
571   addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
572   // TOOL_INCLUDE_DIR
573   AddMultilibIncludeArgs(DriverArgs, CC1Args);
574 
575   // Check for configure-time C include directories.
576   StringRef CIncludeDirs(C_INCLUDE_DIRS);
577   if (CIncludeDirs != "") {
578     SmallVector<StringRef, 5> dirs;
579     CIncludeDirs.split(dirs, ":");
580     for (StringRef dir : dirs) {
581       StringRef Prefix =
582           llvm::sys::path::is_absolute(dir) ? "" : StringRef(SysRoot);
583       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
584     }
585     return;
586   }
587 
588   // On systems using multiarch and Android, add /usr/include/$triple before
589   // /usr/include.
590   std::string MultiarchIncludeDir = getMultiarchTriple(D, getTriple(), SysRoot);
591   if (!MultiarchIncludeDir.empty() &&
592       D.getVFS().exists(SysRoot + "/usr/include/" + MultiarchIncludeDir))
593     addExternCSystemInclude(DriverArgs, CC1Args,
594                             SysRoot + "/usr/include/" + MultiarchIncludeDir);
595 
596   if (getTriple().getOS() == llvm::Triple::RTEMS)
597     return;
598 
599   // Add an include of '/include' directly. This isn't provided by default by
600   // system GCCs, but is often used with cross-compiling GCCs, and harmless to
601   // add even when Clang is acting as-if it were a system compiler.
602   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
603 
604   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
605 
606   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && getTriple().isMusl())
607     addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
608 }
609 
610 void Linux::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
611                                      llvm::opt::ArgStringList &CC1Args) const {
612   // We need a detected GCC installation on Linux to provide libstdc++'s
613   // headers in odd Linuxish places.
614   if (!GCCInstallation.isValid())
615     return;
616 
617   // Detect Debian g++-multiarch-incdir.diff.
618   StringRef TripleStr = GCCInstallation.getTriple().str();
619   StringRef DebianMultiarch =
620       GCCInstallation.getTriple().getArch() == llvm::Triple::x86
621           ? "i386-linux-gnu"
622           : TripleStr;
623 
624   // Try generic GCC detection first.
625   if (Generic_GCC::addGCCLibStdCxxIncludePaths(DriverArgs, CC1Args,
626                                                DebianMultiarch))
627     return;
628 
629   StringRef LibDir = GCCInstallation.getParentLibPath();
630   const Multilib &Multilib = GCCInstallation.getMultilib();
631   const GCCVersion &Version = GCCInstallation.getVersion();
632 
633   const std::string LibStdCXXIncludePathCandidates[] = {
634       // Android standalone toolchain has C++ headers in yet another place.
635       LibDir.str() + "/../" + TripleStr.str() + "/include/c++/" + Version.Text,
636       // Freescale SDK C++ headers are directly in <sysroot>/usr/include/c++,
637       // without a subdirectory corresponding to the gcc version.
638       LibDir.str() + "/../include/c++",
639       // Cray's gcc installation puts headers under "g++" without a
640       // version suffix.
641       LibDir.str() + "/../include/g++",
642   };
643 
644   for (const auto &IncludePath : LibStdCXXIncludePathCandidates) {
645     if (addLibStdCXXIncludePaths(IncludePath, TripleStr,
646                                  Multilib.includeSuffix(), DriverArgs, CC1Args))
647       break;
648   }
649 }
650 
651 void Linux::AddCudaIncludeArgs(const ArgList &DriverArgs,
652                                ArgStringList &CC1Args) const {
653   CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
654 }
655 
656 void Linux::AddHIPIncludeArgs(const ArgList &DriverArgs,
657                               ArgStringList &CC1Args) const {
658   RocmInstallation.AddHIPIncludeArgs(DriverArgs, CC1Args);
659 }
660 
661 void Linux::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
662                                 ArgStringList &CC1Args) const {
663   if (GCCInstallation.isValid()) {
664     CC1Args.push_back("-isystem");
665     CC1Args.push_back(DriverArgs.MakeArgString(
666         GCCInstallation.getParentLibPath() + "/../" +
667         GCCInstallation.getTriple().str() + "/include"));
668   }
669 }
670 
671 bool Linux::isPIEDefault(const llvm::opt::ArgList &Args) const {
672   return CLANG_DEFAULT_PIE_ON_LINUX || getTriple().isAndroid() ||
673          getTriple().isMusl() || getSanitizerArgs(Args).requiresPIE();
674 }
675 
676 bool Linux::IsAArch64OutlineAtomicsDefault(const ArgList &Args) const {
677   // Outline atomics for AArch64 are supported by compiler-rt
678   // and libgcc since 9.3.1
679   assert(getTriple().isAArch64() && "expected AArch64 target!");
680   ToolChain::RuntimeLibType RtLib = GetRuntimeLibType(Args);
681   if (RtLib == ToolChain::RLT_CompilerRT)
682     return true;
683   assert(RtLib == ToolChain::RLT_Libgcc && "unexpected runtime library type!");
684   if (GCCInstallation.getVersion().isOlderThan(9, 3, 1))
685     return false;
686   return true;
687 }
688 
689 bool Linux::IsMathErrnoDefault() const {
690   if (getTriple().isAndroid() || getTriple().isMusl())
691     return false;
692   return Generic_ELF::IsMathErrnoDefault();
693 }
694 
695 SanitizerMask Linux::getSupportedSanitizers() const {
696   const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
697   const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
698   const bool IsMIPS = getTriple().isMIPS32();
699   const bool IsMIPS64 = getTriple().isMIPS64();
700   const bool IsPowerPC64 = getTriple().getArch() == llvm::Triple::ppc64 ||
701                            getTriple().getArch() == llvm::Triple::ppc64le;
702   const bool IsAArch64 = getTriple().getArch() == llvm::Triple::aarch64 ||
703                          getTriple().getArch() == llvm::Triple::aarch64_be;
704   const bool IsArmArch = getTriple().getArch() == llvm::Triple::arm ||
705                          getTriple().getArch() == llvm::Triple::thumb ||
706                          getTriple().getArch() == llvm::Triple::armeb ||
707                          getTriple().getArch() == llvm::Triple::thumbeb;
708   const bool IsRISCV64 = getTriple().getArch() == llvm::Triple::riscv64;
709   const bool IsSystemZ = getTriple().getArch() == llvm::Triple::systemz;
710   const bool IsHexagon = getTriple().getArch() == llvm::Triple::hexagon;
711   SanitizerMask Res = ToolChain::getSupportedSanitizers();
712   Res |= SanitizerKind::Address;
713   Res |= SanitizerKind::PointerCompare;
714   Res |= SanitizerKind::PointerSubtract;
715   Res |= SanitizerKind::Fuzzer;
716   Res |= SanitizerKind::FuzzerNoLink;
717   Res |= SanitizerKind::KernelAddress;
718   Res |= SanitizerKind::Memory;
719   Res |= SanitizerKind::Vptr;
720   Res |= SanitizerKind::SafeStack;
721   if (IsX86_64 || IsMIPS64 || IsAArch64)
722     Res |= SanitizerKind::DataFlow;
723   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsX86 || IsArmArch || IsPowerPC64 ||
724       IsRISCV64 || IsSystemZ || IsHexagon)
725     Res |= SanitizerKind::Leak;
726   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsPowerPC64 || IsSystemZ)
727     Res |= SanitizerKind::Thread;
728   if (IsX86_64)
729     Res |= SanitizerKind::KernelMemory;
730   if (IsX86 || IsX86_64)
731     Res |= SanitizerKind::Function;
732   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsX86 || IsMIPS || IsArmArch ||
733       IsPowerPC64 || IsHexagon)
734     Res |= SanitizerKind::Scudo;
735   if (IsX86_64 || IsAArch64) {
736     Res |= SanitizerKind::HWAddress;
737     Res |= SanitizerKind::KernelHWAddress;
738   }
739   return Res;
740 }
741 
742 void Linux::addProfileRTLibs(const llvm::opt::ArgList &Args,
743                              llvm::opt::ArgStringList &CmdArgs) const {
744   // Add linker option -u__llvm_profile_runtime to cause runtime
745   // initialization module to be linked in.
746   if (needsProfileRT(Args))
747     CmdArgs.push_back(Args.MakeArgString(
748         Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
749   ToolChain::addProfileRTLibs(Args, CmdArgs);
750 }
751 
752 llvm::DenormalMode
753 Linux::getDefaultDenormalModeForType(const llvm::opt::ArgList &DriverArgs,
754                                      const JobAction &JA,
755                                      const llvm::fltSemantics *FPType) const {
756   switch (getTriple().getArch()) {
757   case llvm::Triple::x86:
758   case llvm::Triple::x86_64: {
759     std::string Unused;
760     // DAZ and FTZ are turned on in crtfastmath.o
761     if (!DriverArgs.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles) &&
762         isFastMathRuntimeAvailable(DriverArgs, Unused))
763       return llvm::DenormalMode::getPreserveSign();
764     return llvm::DenormalMode::getIEEE();
765   }
766   default:
767     return llvm::DenormalMode::getIEEE();
768   }
769 }
770 
771 void Linux::addExtraOpts(llvm::opt::ArgStringList &CmdArgs) const {
772   for (const auto &Opt : ExtraOpts)
773     CmdArgs.push_back(Opt.c_str());
774 }
775