xref: /freebsd/contrib/llvm-project/clang/lib/Driver/ToolChains/Linux.cpp (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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/LoongArch.h"
12 #include "Arch/Mips.h"
13 #include "Arch/PPC.h"
14 #include "Arch/RISCV.h"
15 #include "CommonArgs.h"
16 #include "clang/Config/config.h"
17 #include "clang/Driver/Distro.h"
18 #include "clang/Driver/Driver.h"
19 #include "clang/Driver/Options.h"
20 #include "clang/Driver/SanitizerArgs.h"
21 #include "llvm/Option/ArgList.h"
22 #include "llvm/ProfileData/InstrProf.h"
23 #include "llvm/Support/Path.h"
24 #include "llvm/Support/ScopedPrinter.h"
25 #include "llvm/Support/VirtualFileSystem.h"
26 #include <system_error>
27 
28 using namespace clang::driver;
29 using namespace clang::driver::toolchains;
30 using namespace clang;
31 using namespace llvm::opt;
32 
33 using tools::addPathIfExists;
34 
35 /// Get our best guess at the multiarch triple for a target.
36 ///
37 /// Debian-based systems are starting to use a multiarch setup where they use
38 /// a target-triple directory in the library and header search paths.
39 /// Unfortunately, this triple does not align with the vanilla target triple,
40 /// so we provide a rough mapping here.
41 std::string Linux::getMultiarchTriple(const Driver &D,
42                                       const llvm::Triple &TargetTriple,
43                                       StringRef SysRoot) const {
44   llvm::Triple::EnvironmentType TargetEnvironment =
45       TargetTriple.getEnvironment();
46   bool IsAndroid = TargetTriple.isAndroid();
47   bool IsMipsR6 = TargetTriple.getSubArch() == llvm::Triple::MipsSubArch_r6;
48   bool IsMipsN32Abi = TargetTriple.getEnvironment() == llvm::Triple::GNUABIN32;
49 
50   // For most architectures, just use whatever we have rather than trying to be
51   // clever.
52   switch (TargetTriple.getArch()) {
53   default:
54     break;
55 
56   // We use the existence of '/lib/<triple>' as a directory to detect some
57   // common linux triples that don't quite match the Clang triple for both
58   // 32-bit and 64-bit targets. Multiarch fixes its install triples to these
59   // regardless of what the actual target triple is.
60   case llvm::Triple::arm:
61   case llvm::Triple::thumb:
62     if (IsAndroid)
63       return "arm-linux-androideabi";
64     if (TargetEnvironment == llvm::Triple::GNUEABIHF)
65       return "arm-linux-gnueabihf";
66     return "arm-linux-gnueabi";
67   case llvm::Triple::armeb:
68   case llvm::Triple::thumbeb:
69     if (TargetEnvironment == llvm::Triple::GNUEABIHF)
70       return "armeb-linux-gnueabihf";
71     return "armeb-linux-gnueabi";
72   case llvm::Triple::x86:
73     if (IsAndroid)
74       return "i686-linux-android";
75     return "i386-linux-gnu";
76   case llvm::Triple::x86_64:
77     if (IsAndroid)
78       return "x86_64-linux-android";
79     if (TargetEnvironment == llvm::Triple::GNUX32)
80       return "x86_64-linux-gnux32";
81     return "x86_64-linux-gnu";
82   case llvm::Triple::aarch64:
83     if (IsAndroid)
84       return "aarch64-linux-android";
85     return "aarch64-linux-gnu";
86   case llvm::Triple::aarch64_be:
87     return "aarch64_be-linux-gnu";
88 
89   case llvm::Triple::loongarch64: {
90     const char *Libc;
91     const char *FPFlavor;
92 
93     if (TargetTriple.isGNUEnvironment()) {
94       Libc = "gnu";
95     } else if (TargetTriple.isMusl()) {
96       Libc = "musl";
97     } else {
98       return TargetTriple.str();
99     }
100 
101     switch (TargetEnvironment) {
102     default:
103       return TargetTriple.str();
104     case llvm::Triple::GNUSF:
105       FPFlavor = "sf";
106       break;
107     case llvm::Triple::GNUF32:
108       FPFlavor = "f32";
109       break;
110     case llvm::Triple::GNU:
111     case llvm::Triple::GNUF64:
112       // This was going to be "f64" in an earlier Toolchain Conventions
113       // revision, but starting from Feb 2023 the F64 ABI variants are
114       // unmarked in their canonical forms.
115       FPFlavor = "";
116       break;
117     }
118 
119     return (Twine("loongarch64-linux-") + Libc + FPFlavor).str();
120   }
121 
122   case llvm::Triple::m68k:
123     return "m68k-linux-gnu";
124 
125   case llvm::Triple::mips:
126     return IsMipsR6 ? "mipsisa32r6-linux-gnu" : "mips-linux-gnu";
127   case llvm::Triple::mipsel:
128     return IsMipsR6 ? "mipsisa32r6el-linux-gnu" : "mipsel-linux-gnu";
129   case llvm::Triple::mips64: {
130     std::string MT = std::string(IsMipsR6 ? "mipsisa64r6" : "mips64") +
131                      "-linux-" + (IsMipsN32Abi ? "gnuabin32" : "gnuabi64");
132     if (D.getVFS().exists(concat(SysRoot, "/lib", MT)))
133       return MT;
134     if (D.getVFS().exists(concat(SysRoot, "/lib/mips64-linux-gnu")))
135       return "mips64-linux-gnu";
136     break;
137   }
138   case llvm::Triple::mips64el: {
139     std::string MT = std::string(IsMipsR6 ? "mipsisa64r6el" : "mips64el") +
140                      "-linux-" + (IsMipsN32Abi ? "gnuabin32" : "gnuabi64");
141     if (D.getVFS().exists(concat(SysRoot, "/lib", MT)))
142       return MT;
143     if (D.getVFS().exists(concat(SysRoot, "/lib/mips64el-linux-gnu")))
144       return "mips64el-linux-gnu";
145     break;
146   }
147   case llvm::Triple::ppc:
148     if (D.getVFS().exists(concat(SysRoot, "/lib/powerpc-linux-gnuspe")))
149       return "powerpc-linux-gnuspe";
150     return "powerpc-linux-gnu";
151   case llvm::Triple::ppcle:
152     return "powerpcle-linux-gnu";
153   case llvm::Triple::ppc64:
154     return "powerpc64-linux-gnu";
155   case llvm::Triple::ppc64le:
156     return "powerpc64le-linux-gnu";
157   case llvm::Triple::riscv64:
158     if (IsAndroid)
159       return "riscv64-linux-android";
160     return "riscv64-linux-gnu";
161   case llvm::Triple::sparc:
162     return "sparc-linux-gnu";
163   case llvm::Triple::sparcv9:
164     return "sparc64-linux-gnu";
165   case llvm::Triple::systemz:
166     return "s390x-linux-gnu";
167   }
168   return TargetTriple.str();
169 }
170 
171 static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {
172   if (Triple.isMIPS()) {
173     if (Triple.isAndroid()) {
174       StringRef CPUName;
175       StringRef ABIName;
176       tools::mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
177       if (CPUName == "mips32r6")
178         return "libr6";
179       if (CPUName == "mips32r2")
180         return "libr2";
181     }
182     // lib32 directory has a special meaning on MIPS targets.
183     // It contains N32 ABI binaries. Use this folder if produce
184     // code for N32 ABI only.
185     if (tools::mips::hasMipsAbiArg(Args, "n32"))
186       return "lib32";
187     return Triple.isArch32Bit() ? "lib" : "lib64";
188   }
189 
190   // It happens that only x86, PPC and SPARC use the 'lib32' variant of
191   // oslibdir, and using that variant while targeting other architectures causes
192   // problems because the libraries are laid out in shared system roots that
193   // can't cope with a 'lib32' library search path being considered. So we only
194   // enable them when we know we may need it.
195   //
196   // FIXME: This is a bit of a hack. We should really unify this code for
197   // reasoning about oslibdir spellings with the lib dir spellings in the
198   // GCCInstallationDetector, but that is a more significant refactoring.
199   if (Triple.getArch() == llvm::Triple::x86 || Triple.isPPC32() ||
200       Triple.getArch() == llvm::Triple::sparc)
201     return "lib32";
202 
203   if (Triple.getArch() == llvm::Triple::x86_64 && Triple.isX32())
204     return "libx32";
205 
206   if (Triple.getArch() == llvm::Triple::riscv32)
207     return "lib32";
208 
209   return Triple.isArch32Bit() ? "lib" : "lib64";
210 }
211 
212 Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
213     : Generic_ELF(D, Triple, Args) {
214   GCCInstallation.init(Triple, Args);
215   Multilibs = GCCInstallation.getMultilibs();
216   SelectedMultilibs.assign({GCCInstallation.getMultilib()});
217   llvm::Triple::ArchType Arch = Triple.getArch();
218   std::string SysRoot = computeSysRoot();
219   ToolChain::path_list &PPaths = getProgramPaths();
220 
221   Generic_GCC::PushPPaths(PPaths);
222 
223   Distro Distro(D.getVFS(), Triple);
224 
225   if (Distro.IsAlpineLinux() || Triple.isAndroid()) {
226     ExtraOpts.push_back("-z");
227     ExtraOpts.push_back("now");
228   }
229 
230   if (Distro.IsOpenSUSE() || Distro.IsUbuntu() || Distro.IsAlpineLinux() ||
231       Triple.isAndroid()) {
232     ExtraOpts.push_back("-z");
233     ExtraOpts.push_back("relro");
234   }
235 
236   // Android ARM/AArch64 use max-page-size=4096 to reduce VMA usage. Note, lld
237   // from 11 onwards default max-page-size to 65536 for both ARM and AArch64.
238   if ((Triple.isARM() || Triple.isAArch64()) && Triple.isAndroid()) {
239     ExtraOpts.push_back("-z");
240     ExtraOpts.push_back("max-page-size=4096");
241   }
242 
243   if (GCCInstallation.getParentLibPath().contains("opt/rh/"))
244     // With devtoolset on RHEL, we want to add a bin directory that is relative
245     // to the detected gcc install, because if we are using devtoolset gcc then
246     // we want to use other tools from devtoolset (e.g. ld) instead of the
247     // standard system tools.
248     PPaths.push_back(Twine(GCCInstallation.getParentLibPath() +
249                      "/../bin").str());
250 
251   if (Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb)
252     ExtraOpts.push_back("-X");
253 
254   const bool IsAndroid = Triple.isAndroid();
255   const bool IsMips = Triple.isMIPS();
256   const bool IsHexagon = Arch == llvm::Triple::hexagon;
257   const bool IsRISCV = Triple.isRISCV();
258   const bool IsCSKY = Triple.isCSKY();
259 
260   if (IsCSKY && !SelectedMultilibs.empty())
261     SysRoot = SysRoot + SelectedMultilibs.back().osSuffix();
262 
263   if ((IsMips || IsCSKY) && !SysRoot.empty())
264     ExtraOpts.push_back("--sysroot=" + SysRoot);
265 
266   // Do not use 'gnu' hash style for Mips targets because .gnu.hash
267   // and the MIPS ABI require .dynsym to be sorted in different ways.
268   // .gnu.hash needs symbols to be grouped by hash code whereas the MIPS
269   // ABI requires a mapping between the GOT and the symbol table.
270   // Android loader does not support .gnu.hash until API 23.
271   // Hexagon linker/loader does not support .gnu.hash
272   if (!IsMips && !IsHexagon) {
273     if (Distro.IsOpenSUSE() || Distro == Distro::UbuntuLucid ||
274         Distro == Distro::UbuntuJaunty || Distro == Distro::UbuntuKarmic ||
275         (IsAndroid && Triple.isAndroidVersionLT(23)))
276       ExtraOpts.push_back("--hash-style=both");
277     else
278       ExtraOpts.push_back("--hash-style=gnu");
279   }
280 
281 #ifdef ENABLE_LINKER_BUILD_ID
282   ExtraOpts.push_back("--build-id");
283 #endif
284 
285   // The selection of paths to try here is designed to match the patterns which
286   // the GCC driver itself uses, as this is part of the GCC-compatible driver.
287   // This was determined by running GCC in a fake filesystem, creating all
288   // possible permutations of these directories, and seeing which ones it added
289   // to the link paths.
290   path_list &Paths = getFilePaths();
291 
292   const std::string OSLibDir = std::string(getOSLibDir(Triple, Args));
293   const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);
294 
295   // mips32: Debian multilib, we use /libo32, while in other case, /lib is
296   // used. We need add both libo32 and /lib.
297   if (Arch == llvm::Triple::mips || Arch == llvm::Triple::mipsel) {
298     Generic_GCC::AddMultilibPaths(D, SysRoot, "libo32", MultiarchTriple, Paths);
299     addPathIfExists(D, concat(SysRoot, "/libo32"), Paths);
300     addPathIfExists(D, concat(SysRoot, "/usr/libo32"), Paths);
301   }
302   Generic_GCC::AddMultilibPaths(D, SysRoot, OSLibDir, MultiarchTriple, Paths);
303 
304   addPathIfExists(D, concat(SysRoot, "/lib", MultiarchTriple), Paths);
305   addPathIfExists(D, concat(SysRoot, "/lib/..", OSLibDir), Paths);
306 
307   if (IsAndroid) {
308     // Android sysroots contain a library directory for each supported OS
309     // version as well as some unversioned libraries in the usual multiarch
310     // directory.
311     addPathIfExists(
312         D,
313         concat(SysRoot, "/usr/lib", MultiarchTriple,
314                llvm::to_string(Triple.getEnvironmentVersion().getMajor())),
315         Paths);
316   }
317 
318   addPathIfExists(D, concat(SysRoot, "/usr/lib", MultiarchTriple), Paths);
319   // 64-bit OpenEmbedded sysroots may not have a /usr/lib dir. So they cannot
320   // find /usr/lib64 as it is referenced as /usr/lib/../lib64. So we handle
321   // this here.
322   if (Triple.getVendor() == llvm::Triple::OpenEmbedded &&
323       Triple.isArch64Bit())
324     addPathIfExists(D, concat(SysRoot, "/usr", OSLibDir), Paths);
325   else
326     addPathIfExists(D, concat(SysRoot, "/usr/lib/..", OSLibDir), Paths);
327   if (IsRISCV) {
328     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
329     addPathIfExists(D, concat(SysRoot, "/", OSLibDir, ABIName), Paths);
330     addPathIfExists(D, concat(SysRoot, "/usr", OSLibDir, ABIName), Paths);
331   }
332 
333   Generic_GCC::AddMultiarchPaths(D, SysRoot, OSLibDir, Paths);
334 
335   addPathIfExists(D, concat(SysRoot, "/lib"), Paths);
336   addPathIfExists(D, concat(SysRoot, "/usr/lib"), Paths);
337 }
338 
339 ToolChain::RuntimeLibType Linux::GetDefaultRuntimeLibType() const {
340   if (getTriple().isAndroid())
341     return ToolChain::RLT_CompilerRT;
342   return Generic_ELF::GetDefaultRuntimeLibType();
343 }
344 
345 unsigned Linux::GetDefaultDwarfVersion() const {
346   if (getTriple().isAndroid())
347     return 4;
348   return ToolChain::GetDefaultDwarfVersion();
349 }
350 
351 ToolChain::CXXStdlibType Linux::GetDefaultCXXStdlibType() const {
352   if (getTriple().isAndroid())
353     return ToolChain::CST_Libcxx;
354   return ToolChain::CST_Libstdcxx;
355 }
356 
357 bool Linux::HasNativeLLVMSupport() const { return true; }
358 
359 Tool *Linux::buildLinker() const { return new tools::gnutools::Linker(*this); }
360 
361 Tool *Linux::buildStaticLibTool() const {
362   return new tools::gnutools::StaticLibTool(*this);
363 }
364 
365 Tool *Linux::buildAssembler() const {
366   return new tools::gnutools::Assembler(*this);
367 }
368 
369 std::string Linux::computeSysRoot() const {
370   if (!getDriver().SysRoot.empty())
371     return getDriver().SysRoot;
372 
373   if (getTriple().isAndroid()) {
374     // Android toolchains typically include a sysroot at ../sysroot relative to
375     // the clang binary.
376     const StringRef ClangDir = getDriver().getInstalledDir();
377     std::string AndroidSysRootPath = (ClangDir + "/../sysroot").str();
378     if (getVFS().exists(AndroidSysRootPath))
379       return AndroidSysRootPath;
380   }
381 
382   if (getTriple().isCSKY()) {
383     // CSKY toolchains use different names for sysroot folder.
384     if (!GCCInstallation.isValid())
385       return std::string();
386     // GCCInstallation.getInstallPath() =
387     //   $GCCToolchainPath/lib/gcc/csky-linux-gnuabiv2/6.3.0
388     // Path = $GCCToolchainPath/csky-linux-gnuabiv2/libc
389     std::string Path = (GCCInstallation.getInstallPath() + "/../../../../" +
390                         GCCInstallation.getTriple().str() + "/libc")
391                            .str();
392     if (getVFS().exists(Path))
393       return Path;
394     return std::string();
395   }
396 
397   if (!GCCInstallation.isValid() || !getTriple().isMIPS())
398     return std::string();
399 
400   // Standalone MIPS toolchains use different names for sysroot folder
401   // and put it into different places. Here we try to check some known
402   // variants.
403 
404   const StringRef InstallDir = GCCInstallation.getInstallPath();
405   const StringRef TripleStr = GCCInstallation.getTriple().str();
406   const Multilib &Multilib = GCCInstallation.getMultilib();
407 
408   std::string Path =
409       (InstallDir + "/../../../../" + TripleStr + "/libc" + Multilib.osSuffix())
410           .str();
411 
412   if (getVFS().exists(Path))
413     return Path;
414 
415   Path = (InstallDir + "/../../../../sysroot" + Multilib.osSuffix()).str();
416 
417   if (getVFS().exists(Path))
418     return Path;
419 
420   return std::string();
421 }
422 
423 std::string Linux::getDynamicLinker(const ArgList &Args) const {
424   const llvm::Triple::ArchType Arch = getArch();
425   const llvm::Triple &Triple = getTriple();
426 
427   const Distro Distro(getDriver().getVFS(), Triple);
428 
429   if (Triple.isAndroid()) {
430     if (getSanitizerArgs(Args).needsHwasanRt() &&
431         !Triple.isAndroidVersionLT(34) && Triple.isArch64Bit()) {
432       // On Android 14 and newer, there is a special linker_hwasan64 that
433       // allows to run HWASan binaries on non-HWASan system images. This
434       // is also available on HWASan system images, so we can just always
435       // use that instead.
436       return "/system/bin/linker_hwasan64";
437     }
438     return Triple.isArch64Bit() ? "/system/bin/linker64" : "/system/bin/linker";
439   }
440   if (Triple.isMusl()) {
441     std::string ArchName;
442     bool IsArm = false;
443 
444     switch (Arch) {
445     case llvm::Triple::arm:
446     case llvm::Triple::thumb:
447       ArchName = "arm";
448       IsArm = true;
449       break;
450     case llvm::Triple::armeb:
451     case llvm::Triple::thumbeb:
452       ArchName = "armeb";
453       IsArm = true;
454       break;
455     case llvm::Triple::x86:
456       ArchName = "i386";
457       break;
458     case llvm::Triple::x86_64:
459       ArchName = Triple.isX32() ? "x32" : Triple.getArchName().str();
460       break;
461     default:
462       ArchName = Triple.getArchName().str();
463     }
464     if (IsArm &&
465         (Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
466          tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard))
467       ArchName += "hf";
468     if (Arch == llvm::Triple::ppc &&
469         Triple.getSubArch() == llvm::Triple::PPCSubArch_spe)
470       ArchName = "powerpc-sf";
471 
472     return "/lib/ld-musl-" + ArchName + ".so.1";
473   }
474 
475   std::string LibDir;
476   std::string Loader;
477 
478   switch (Arch) {
479   default:
480     llvm_unreachable("unsupported architecture");
481 
482   case llvm::Triple::aarch64:
483     LibDir = "lib";
484     Loader = "ld-linux-aarch64.so.1";
485     break;
486   case llvm::Triple::aarch64_be:
487     LibDir = "lib";
488     Loader = "ld-linux-aarch64_be.so.1";
489     break;
490   case llvm::Triple::arm:
491   case llvm::Triple::thumb:
492   case llvm::Triple::armeb:
493   case llvm::Triple::thumbeb: {
494     const bool HF =
495         Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
496         tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard;
497 
498     LibDir = "lib";
499     Loader = HF ? "ld-linux-armhf.so.3" : "ld-linux.so.3";
500     break;
501   }
502   case llvm::Triple::loongarch32: {
503     LibDir = "lib32";
504     Loader =
505         ("ld-linux-loongarch-" +
506          tools::loongarch::getLoongArchABI(getDriver(), Args, Triple) + ".so.1")
507             .str();
508     break;
509   }
510   case llvm::Triple::loongarch64: {
511     LibDir = "lib64";
512     Loader =
513         ("ld-linux-loongarch-" +
514          tools::loongarch::getLoongArchABI(getDriver(), Args, Triple) + ".so.1")
515             .str();
516     break;
517   }
518   case llvm::Triple::m68k:
519     LibDir = "lib";
520     Loader = "ld.so.1";
521     break;
522   case llvm::Triple::mips:
523   case llvm::Triple::mipsel:
524   case llvm::Triple::mips64:
525   case llvm::Triple::mips64el: {
526     bool IsNaN2008 = tools::mips::isNaN2008(getDriver(), Args, Triple);
527 
528     LibDir = "lib" + tools::mips::getMipsABILibSuffix(Args, Triple);
529 
530     if (tools::mips::isUCLibc(Args))
531       Loader = IsNaN2008 ? "ld-uClibc-mipsn8.so.0" : "ld-uClibc.so.0";
532     else if (!Triple.hasEnvironment() &&
533              Triple.getVendor() == llvm::Triple::VendorType::MipsTechnologies)
534       Loader =
535           Triple.isLittleEndian() ? "ld-musl-mipsel.so.1" : "ld-musl-mips.so.1";
536     else
537       Loader = IsNaN2008 ? "ld-linux-mipsn8.so.1" : "ld.so.1";
538 
539     break;
540   }
541   case llvm::Triple::ppc:
542     LibDir = "lib";
543     Loader = "ld.so.1";
544     break;
545   case llvm::Triple::ppcle:
546     LibDir = "lib";
547     Loader = "ld.so.1";
548     break;
549   case llvm::Triple::ppc64:
550     LibDir = "lib64";
551     Loader =
552         (tools::ppc::hasPPCAbiArg(Args, "elfv2")) ? "ld64.so.2" : "ld64.so.1";
553     break;
554   case llvm::Triple::ppc64le:
555     LibDir = "lib64";
556     Loader =
557         (tools::ppc::hasPPCAbiArg(Args, "elfv1")) ? "ld64.so.1" : "ld64.so.2";
558     break;
559   case llvm::Triple::riscv32: {
560     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
561     LibDir = "lib";
562     Loader = ("ld-linux-riscv32-" + ABIName + ".so.1").str();
563     break;
564   }
565   case llvm::Triple::riscv64: {
566     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
567     LibDir = "lib";
568     Loader = ("ld-linux-riscv64-" + ABIName + ".so.1").str();
569     break;
570   }
571   case llvm::Triple::sparc:
572   case llvm::Triple::sparcel:
573     LibDir = "lib";
574     Loader = "ld-linux.so.2";
575     break;
576   case llvm::Triple::sparcv9:
577     LibDir = "lib64";
578     Loader = "ld-linux.so.2";
579     break;
580   case llvm::Triple::systemz:
581     LibDir = "lib";
582     Loader = "ld64.so.1";
583     break;
584   case llvm::Triple::x86:
585     LibDir = "lib";
586     Loader = "ld-linux.so.2";
587     break;
588   case llvm::Triple::x86_64: {
589     bool X32 = Triple.isX32();
590 
591     LibDir = X32 ? "libx32" : "lib64";
592     Loader = X32 ? "ld-linux-x32.so.2" : "ld-linux-x86-64.so.2";
593     break;
594   }
595   case llvm::Triple::ve:
596     return "/opt/nec/ve/lib/ld-linux-ve.so.1";
597   case llvm::Triple::csky: {
598     LibDir = "lib";
599     Loader = "ld.so.1";
600     break;
601   }
602   }
603 
604   if (Distro == Distro::Exherbo &&
605       (Triple.getVendor() == llvm::Triple::UnknownVendor ||
606        Triple.getVendor() == llvm::Triple::PC))
607     return "/usr/" + Triple.str() + "/lib/" + Loader;
608   return "/" + LibDir + "/" + Loader;
609 }
610 
611 void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
612                                       ArgStringList &CC1Args) const {
613   const Driver &D = getDriver();
614   std::string SysRoot = computeSysRoot();
615 
616   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
617     return;
618 
619   // Add 'include' in the resource directory, which is similar to
620   // GCC_INCLUDE_DIR (private headers) in GCC. Note: the include directory
621   // contains some files conflicting with system /usr/include. musl systems
622   // prefer the /usr/include copies which are more relevant.
623   SmallString<128> ResourceDirInclude(D.ResourceDir);
624   llvm::sys::path::append(ResourceDirInclude, "include");
625   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) &&
626       (!getTriple().isMusl() || DriverArgs.hasArg(options::OPT_nostdlibinc)))
627     addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
628 
629   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
630     return;
631 
632   // LOCAL_INCLUDE_DIR
633   addSystemInclude(DriverArgs, CC1Args, concat(SysRoot, "/usr/local/include"));
634   // TOOL_INCLUDE_DIR
635   AddMultilibIncludeArgs(DriverArgs, CC1Args);
636 
637   // Check for configure-time C include directories.
638   StringRef CIncludeDirs(C_INCLUDE_DIRS);
639   if (CIncludeDirs != "") {
640     SmallVector<StringRef, 5> dirs;
641     CIncludeDirs.split(dirs, ":");
642     for (StringRef dir : dirs) {
643       StringRef Prefix =
644           llvm::sys::path::is_absolute(dir) ? "" : StringRef(SysRoot);
645       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
646     }
647     return;
648   }
649 
650   // On systems using multiarch and Android, add /usr/include/$triple before
651   // /usr/include.
652   std::string MultiarchIncludeDir = getMultiarchTriple(D, getTriple(), SysRoot);
653   if (!MultiarchIncludeDir.empty() &&
654       D.getVFS().exists(concat(SysRoot, "/usr/include", MultiarchIncludeDir)))
655     addExternCSystemInclude(
656         DriverArgs, CC1Args,
657         concat(SysRoot, "/usr/include", MultiarchIncludeDir));
658 
659   if (getTriple().getOS() == llvm::Triple::RTEMS)
660     return;
661 
662   // Add an include of '/include' directly. This isn't provided by default by
663   // system GCCs, but is often used with cross-compiling GCCs, and harmless to
664   // add even when Clang is acting as-if it were a system compiler.
665   addExternCSystemInclude(DriverArgs, CC1Args, concat(SysRoot, "/include"));
666 
667   addExternCSystemInclude(DriverArgs, CC1Args, concat(SysRoot, "/usr/include"));
668 
669   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && getTriple().isMusl())
670     addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
671 }
672 
673 void Linux::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
674                                      llvm::opt::ArgStringList &CC1Args) const {
675   // We need a detected GCC installation on Linux to provide libstdc++'s
676   // headers in odd Linuxish places.
677   if (!GCCInstallation.isValid())
678     return;
679 
680   // Detect Debian g++-multiarch-incdir.diff.
681   StringRef TripleStr = GCCInstallation.getTriple().str();
682   StringRef DebianMultiarch =
683       GCCInstallation.getTriple().getArch() == llvm::Triple::x86
684           ? "i386-linux-gnu"
685           : TripleStr;
686 
687   // Try generic GCC detection first.
688   if (Generic_GCC::addGCCLibStdCxxIncludePaths(DriverArgs, CC1Args,
689                                                DebianMultiarch))
690     return;
691 
692   StringRef LibDir = GCCInstallation.getParentLibPath();
693   const Multilib &Multilib = GCCInstallation.getMultilib();
694   const GCCVersion &Version = GCCInstallation.getVersion();
695 
696   const std::string LibStdCXXIncludePathCandidates[] = {
697       // Android standalone toolchain has C++ headers in yet another place.
698       LibDir.str() + "/../" + TripleStr.str() + "/include/c++/" + Version.Text,
699       // Freescale SDK C++ headers are directly in <sysroot>/usr/include/c++,
700       // without a subdirectory corresponding to the gcc version.
701       LibDir.str() + "/../include/c++",
702       // Cray's gcc installation puts headers under "g++" without a
703       // version suffix.
704       LibDir.str() + "/../include/g++",
705   };
706 
707   for (const auto &IncludePath : LibStdCXXIncludePathCandidates) {
708     if (addLibStdCXXIncludePaths(IncludePath, TripleStr,
709                                  Multilib.includeSuffix(), DriverArgs, CC1Args))
710       break;
711   }
712 }
713 
714 void Linux::AddCudaIncludeArgs(const ArgList &DriverArgs,
715                                ArgStringList &CC1Args) const {
716   CudaInstallation->AddCudaIncludeArgs(DriverArgs, CC1Args);
717 }
718 
719 void Linux::AddHIPIncludeArgs(const ArgList &DriverArgs,
720                               ArgStringList &CC1Args) const {
721   RocmInstallation->AddHIPIncludeArgs(DriverArgs, CC1Args);
722 }
723 
724 void Linux::AddHIPRuntimeLibArgs(const ArgList &Args,
725                                  ArgStringList &CmdArgs) const {
726   CmdArgs.push_back(
727       Args.MakeArgString(StringRef("-L") + RocmInstallation->getLibPath()));
728 
729   if (Args.hasFlag(options::OPT_frtlib_add_rpath,
730                    options::OPT_fno_rtlib_add_rpath, false))
731     CmdArgs.append(
732         {"-rpath", Args.MakeArgString(RocmInstallation->getLibPath())});
733 
734   CmdArgs.push_back("-lamdhip64");
735 }
736 
737 void Linux::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
738                                 ArgStringList &CC1Args) const {
739   if (GCCInstallation.isValid()) {
740     CC1Args.push_back("-isystem");
741     CC1Args.push_back(DriverArgs.MakeArgString(
742         GCCInstallation.getParentLibPath() + "/../" +
743         GCCInstallation.getTriple().str() + "/include"));
744   }
745 }
746 
747 bool Linux::isPIEDefault(const llvm::opt::ArgList &Args) const {
748   return CLANG_DEFAULT_PIE_ON_LINUX || getTriple().isAndroid() ||
749          getTriple().isMusl() || getSanitizerArgs(Args).requiresPIE();
750 }
751 
752 bool Linux::IsAArch64OutlineAtomicsDefault(const ArgList &Args) const {
753   // Outline atomics for AArch64 are supported by compiler-rt
754   // and libgcc since 9.3.1
755   assert(getTriple().isAArch64() && "expected AArch64 target!");
756   ToolChain::RuntimeLibType RtLib = GetRuntimeLibType(Args);
757   if (RtLib == ToolChain::RLT_CompilerRT)
758     return true;
759   assert(RtLib == ToolChain::RLT_Libgcc && "unexpected runtime library type!");
760   if (GCCInstallation.getVersion().isOlderThan(9, 3, 1))
761     return false;
762   return true;
763 }
764 
765 bool Linux::IsMathErrnoDefault() const {
766   if (getTriple().isAndroid() || getTriple().isMusl())
767     return false;
768   return Generic_ELF::IsMathErrnoDefault();
769 }
770 
771 SanitizerMask Linux::getSupportedSanitizers() const {
772   const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
773   const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
774   const bool IsMIPS = getTriple().isMIPS32();
775   const bool IsMIPS64 = getTriple().isMIPS64();
776   const bool IsPowerPC64 = getTriple().getArch() == llvm::Triple::ppc64 ||
777                            getTriple().getArch() == llvm::Triple::ppc64le;
778   const bool IsAArch64 = getTriple().getArch() == llvm::Triple::aarch64 ||
779                          getTriple().getArch() == llvm::Triple::aarch64_be;
780   const bool IsArmArch = getTriple().getArch() == llvm::Triple::arm ||
781                          getTriple().getArch() == llvm::Triple::thumb ||
782                          getTriple().getArch() == llvm::Triple::armeb ||
783                          getTriple().getArch() == llvm::Triple::thumbeb;
784   const bool IsLoongArch64 = getTriple().getArch() == llvm::Triple::loongarch64;
785   const bool IsRISCV64 = getTriple().getArch() == llvm::Triple::riscv64;
786   const bool IsSystemZ = getTriple().getArch() == llvm::Triple::systemz;
787   const bool IsHexagon = getTriple().getArch() == llvm::Triple::hexagon;
788   SanitizerMask Res = ToolChain::getSupportedSanitizers();
789   Res |= SanitizerKind::Address;
790   Res |= SanitizerKind::PointerCompare;
791   Res |= SanitizerKind::PointerSubtract;
792   Res |= SanitizerKind::Fuzzer;
793   Res |= SanitizerKind::FuzzerNoLink;
794   Res |= SanitizerKind::KernelAddress;
795   Res |= SanitizerKind::Memory;
796   Res |= SanitizerKind::Vptr;
797   Res |= SanitizerKind::SafeStack;
798   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsLoongArch64)
799     Res |= SanitizerKind::DataFlow;
800   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsX86 || IsArmArch || IsPowerPC64 ||
801       IsRISCV64 || IsSystemZ || IsHexagon || IsLoongArch64)
802     Res |= SanitizerKind::Leak;
803   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsPowerPC64 || IsSystemZ ||
804       IsLoongArch64)
805     Res |= SanitizerKind::Thread;
806   if (IsX86_64 || IsSystemZ)
807     Res |= SanitizerKind::KernelMemory;
808   if (IsX86_64 || IsMIPS64 || IsAArch64 || IsX86 || IsMIPS || IsArmArch ||
809       IsPowerPC64 || IsHexagon || IsLoongArch64 || IsRISCV64)
810     Res |= SanitizerKind::Scudo;
811   if (IsX86_64 || IsAArch64 || IsRISCV64) {
812     Res |= SanitizerKind::HWAddress;
813   }
814   if (IsX86_64 || IsAArch64) {
815     Res |= SanitizerKind::KernelHWAddress;
816   }
817   // Work around "Cannot represent a difference across sections".
818   if (getTriple().getArch() == llvm::Triple::ppc64)
819     Res &= ~SanitizerKind::Function;
820   return Res;
821 }
822 
823 void Linux::addProfileRTLibs(const llvm::opt::ArgList &Args,
824                              llvm::opt::ArgStringList &CmdArgs) const {
825   // Add linker option -u__llvm_profile_runtime to cause runtime
826   // initialization module to be linked in.
827   if (needsProfileRT(Args))
828     CmdArgs.push_back(Args.MakeArgString(
829         Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
830   ToolChain::addProfileRTLibs(Args, CmdArgs);
831 }
832 
833 llvm::DenormalMode
834 Linux::getDefaultDenormalModeForType(const llvm::opt::ArgList &DriverArgs,
835                                      const JobAction &JA,
836                                      const llvm::fltSemantics *FPType) const {
837   switch (getTriple().getArch()) {
838   case llvm::Triple::x86:
839   case llvm::Triple::x86_64: {
840     std::string Unused;
841     // DAZ and FTZ are turned on in crtfastmath.o
842     if (!DriverArgs.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles) &&
843         isFastMathRuntimeAvailable(DriverArgs, Unused))
844       return llvm::DenormalMode::getPreserveSign();
845     return llvm::DenormalMode::getIEEE();
846   }
847   default:
848     return llvm::DenormalMode::getIEEE();
849   }
850 }
851 
852 void Linux::addExtraOpts(llvm::opt::ArgStringList &CmdArgs) const {
853   for (const auto &Opt : ExtraOpts)
854     CmdArgs.push_back(Opt.c_str());
855 }
856 
857 const char *Linux::getDefaultLinker() const {
858   if (getTriple().isAndroid())
859     return "ld.lld";
860   return Generic_ELF::getDefaultLinker();
861 }
862