1 //===--- CommonArgs.cpp - Args handling for multiple toolchains -*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "CommonArgs.h"
11 #include "Arch/AArch64.h"
12 #include "Arch/ARM.h"
13 #include "Arch/Mips.h"
14 #include "Arch/PPC.h"
15 #include "Arch/SystemZ.h"
16 #include "Arch/X86.h"
17 #include "Hexagon.h"
18 #include "InputInfo.h"
19 #include "clang/Basic/CharInfo.h"
20 #include "clang/Basic/LangOptions.h"
21 #include "clang/Basic/ObjCRuntime.h"
22 #include "clang/Basic/Version.h"
23 #include "clang/Basic/VirtualFileSystem.h"
24 #include "clang/Config/config.h"
25 #include "clang/Driver/Action.h"
26 #include "clang/Driver/Compilation.h"
27 #include "clang/Driver/Driver.h"
28 #include "clang/Driver/DriverDiagnostic.h"
29 #include "clang/Driver/Job.h"
30 #include "clang/Driver/Options.h"
31 #include "clang/Driver/SanitizerArgs.h"
32 #include "clang/Driver/ToolChain.h"
33 #include "clang/Driver/Util.h"
34 #include "clang/Driver/XRayArgs.h"
35 #include "llvm/ADT/STLExtras.h"
36 #include "llvm/ADT/SmallString.h"
37 #include "llvm/ADT/StringExtras.h"
38 #include "llvm/ADT/StringSwitch.h"
39 #include "llvm/ADT/Twine.h"
40 #include "llvm/Option/Arg.h"
41 #include "llvm/Option/ArgList.h"
42 #include "llvm/Option/Option.h"
43 #include "llvm/Support/CodeGen.h"
44 #include "llvm/Support/Compression.h"
45 #include "llvm/Support/Debug.h"
46 #include "llvm/Support/ErrorHandling.h"
47 #include "llvm/Support/FileSystem.h"
48 #include "llvm/Support/Host.h"
49 #include "llvm/Support/Path.h"
50 #include "llvm/Support/Process.h"
51 #include "llvm/Support/Program.h"
52 #include "llvm/Support/ScopedPrinter.h"
53 #include "llvm/Support/TargetParser.h"
54 #include "llvm/Support/YAMLParser.h"
55 
56 using namespace clang::driver;
57 using namespace clang::driver::tools;
58 using namespace clang;
59 using namespace llvm::opt;
60 
61 void tools::addPathIfExists(const Driver &D, const Twine &Path,
62                             ToolChain::path_list &Paths) {
63   if (D.getVFS().exists(Path))
64     Paths.push_back(Path.str());
65 }
66 
67 void tools::handleTargetFeaturesGroup(const ArgList &Args,
68                                       std::vector<StringRef> &Features,
69                                       OptSpecifier Group) {
70   for (const Arg *A : Args.filtered(Group)) {
71     StringRef Name = A->getOption().getName();
72     A->claim();
73 
74     // Skip over "-m".
75     assert(Name.startswith("m") && "Invalid feature name.");
76     Name = Name.substr(1);
77 
78     bool IsNegative = Name.startswith("no-");
79     if (IsNegative)
80       Name = Name.substr(3);
81     Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name));
82   }
83 }
84 
85 void tools::addDirectoryList(const ArgList &Args, ArgStringList &CmdArgs,
86                              const char *ArgName, const char *EnvVar) {
87   const char *DirList = ::getenv(EnvVar);
88   bool CombinedArg = false;
89 
90   if (!DirList)
91     return; // Nothing to do.
92 
93   StringRef Name(ArgName);
94   if (Name.equals("-I") || Name.equals("-L"))
95     CombinedArg = true;
96 
97   StringRef Dirs(DirList);
98   if (Dirs.empty()) // Empty string should not add '.'.
99     return;
100 
101   StringRef::size_type Delim;
102   while ((Delim = Dirs.find(llvm::sys::EnvPathSeparator)) != StringRef::npos) {
103     if (Delim == 0) { // Leading colon.
104       if (CombinedArg) {
105         CmdArgs.push_back(Args.MakeArgString(std::string(ArgName) + "."));
106       } else {
107         CmdArgs.push_back(ArgName);
108         CmdArgs.push_back(".");
109       }
110     } else {
111       if (CombinedArg) {
112         CmdArgs.push_back(
113             Args.MakeArgString(std::string(ArgName) + Dirs.substr(0, Delim)));
114       } else {
115         CmdArgs.push_back(ArgName);
116         CmdArgs.push_back(Args.MakeArgString(Dirs.substr(0, Delim)));
117       }
118     }
119     Dirs = Dirs.substr(Delim + 1);
120   }
121 
122   if (Dirs.empty()) { // Trailing colon.
123     if (CombinedArg) {
124       CmdArgs.push_back(Args.MakeArgString(std::string(ArgName) + "."));
125     } else {
126       CmdArgs.push_back(ArgName);
127       CmdArgs.push_back(".");
128     }
129   } else { // Add the last path.
130     if (CombinedArg) {
131       CmdArgs.push_back(Args.MakeArgString(std::string(ArgName) + Dirs));
132     } else {
133       CmdArgs.push_back(ArgName);
134       CmdArgs.push_back(Args.MakeArgString(Dirs));
135     }
136   }
137 }
138 
139 void tools::AddLinkerInputs(const ToolChain &TC, const InputInfoList &Inputs,
140                             const ArgList &Args, ArgStringList &CmdArgs,
141                             const JobAction &JA) {
142   const Driver &D = TC.getDriver();
143 
144   // Add extra linker input arguments which are not treated as inputs
145   // (constructed via -Xarch_).
146   Args.AddAllArgValues(CmdArgs, options::OPT_Zlinker_input);
147 
148   for (const auto &II : Inputs) {
149     // If the current tool chain refers to an OpenMP offloading host, we should
150     // ignore inputs that refer to OpenMP offloading devices - they will be
151     // embedded according to a proper linker script.
152     if (auto *IA = II.getAction())
153       if (JA.isHostOffloading(Action::OFK_OpenMP) &&
154           IA->isDeviceOffloading(Action::OFK_OpenMP))
155         continue;
156 
157     if (!TC.HasNativeLLVMSupport() && types::isLLVMIR(II.getType()))
158       // Don't try to pass LLVM inputs unless we have native support.
159       D.Diag(diag::err_drv_no_linker_llvm_support) << TC.getTripleString();
160 
161     // Add filenames immediately.
162     if (II.isFilename()) {
163       CmdArgs.push_back(II.getFilename());
164       continue;
165     }
166 
167     // Otherwise, this is a linker input argument.
168     const Arg &A = II.getInputArg();
169 
170     // Handle reserved library options.
171     if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx))
172       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
173     else if (A.getOption().matches(options::OPT_Z_reserved_lib_cckext))
174       TC.AddCCKextLibArgs(Args, CmdArgs);
175     else if (A.getOption().matches(options::OPT_z)) {
176       // Pass -z prefix for gcc linker compatibility.
177       A.claim();
178       A.render(Args, CmdArgs);
179     } else {
180       A.renderAsInput(Args, CmdArgs);
181     }
182   }
183 
184   // LIBRARY_PATH - included following the user specified library paths.
185   //                and only supported on native toolchains.
186   if (!TC.isCrossCompiling()) {
187     addDirectoryList(Args, CmdArgs, "-L", "LIBRARY_PATH");
188   }
189 }
190 
191 void tools::AddTargetFeature(const ArgList &Args,
192                              std::vector<StringRef> &Features,
193                              OptSpecifier OnOpt, OptSpecifier OffOpt,
194                              StringRef FeatureName) {
195   if (Arg *A = Args.getLastArg(OnOpt, OffOpt)) {
196     if (A->getOption().matches(OnOpt))
197       Features.push_back(Args.MakeArgString("+" + FeatureName));
198     else
199       Features.push_back(Args.MakeArgString("-" + FeatureName));
200   }
201 }
202 
203 /// Get the (LLVM) name of the R600 gpu we are targeting.
204 static std::string getR600TargetGPU(const ArgList &Args) {
205   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
206     const char *GPUName = A->getValue();
207     return llvm::StringSwitch<const char *>(GPUName)
208         .Cases("rv630", "rv635", "r600")
209         .Cases("rv610", "rv620", "rs780", "rs880")
210         .Case("rv740", "rv770")
211         .Case("palm", "cedar")
212         .Cases("sumo", "sumo2", "sumo")
213         .Case("hemlock", "cypress")
214         .Case("aruba", "cayman")
215         .Default(GPUName);
216   }
217   return "";
218 }
219 
220 static std::string getNios2TargetCPU(const ArgList &Args) {
221   Arg *A = Args.getLastArg(options::OPT_mcpu_EQ);
222   if (!A)
223     A = Args.getLastArg(options::OPT_march_EQ);
224 
225   if (!A)
226     return "";
227 
228   const char *name = A->getValue();
229   return llvm::StringSwitch<const char *>(name)
230       .Case("r1", "nios2r1")
231       .Case("r2", "nios2r2")
232       .Default(name);
233 }
234 
235 static std::string getLanaiTargetCPU(const ArgList &Args) {
236   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
237     return A->getValue();
238   }
239   return "";
240 }
241 
242 /// Get the (LLVM) name of the WebAssembly cpu we are targeting.
243 static StringRef getWebAssemblyTargetCPU(const ArgList &Args) {
244   // If we have -mcpu=, use that.
245   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
246     StringRef CPU = A->getValue();
247 
248 #ifdef __wasm__
249     // Handle "native" by examining the host. "native" isn't meaningful when
250     // cross compiling, so only support this when the host is also WebAssembly.
251     if (CPU == "native")
252       return llvm::sys::getHostCPUName();
253 #endif
254 
255     return CPU;
256   }
257 
258   return "generic";
259 }
260 
261 std::string tools::getCPUName(const ArgList &Args, const llvm::Triple &T,
262                               bool FromAs) {
263   Arg *A;
264 
265   switch (T.getArch()) {
266   default:
267     return "";
268 
269   case llvm::Triple::aarch64:
270   case llvm::Triple::aarch64_be:
271     return aarch64::getAArch64TargetCPU(Args, A);
272 
273   case llvm::Triple::arm:
274   case llvm::Triple::armeb:
275   case llvm::Triple::thumb:
276   case llvm::Triple::thumbeb: {
277     StringRef MArch, MCPU;
278     arm::getARMArchCPUFromArgs(Args, MArch, MCPU, FromAs);
279     return arm::getARMTargetCPU(MCPU, MArch, T);
280   }
281 
282   case llvm::Triple::avr:
283     if (const Arg *A = Args.getLastArg(options::OPT_mmcu_EQ))
284       return A->getValue();
285     return "";
286 
287   case llvm::Triple::nios2: {
288     return getNios2TargetCPU(Args);
289   }
290 
291   case llvm::Triple::mips:
292   case llvm::Triple::mipsel:
293   case llvm::Triple::mips64:
294   case llvm::Triple::mips64el: {
295     StringRef CPUName;
296     StringRef ABIName;
297     mips::getMipsCPUAndABI(Args, T, CPUName, ABIName);
298     return CPUName;
299   }
300 
301   case llvm::Triple::nvptx:
302   case llvm::Triple::nvptx64:
303     if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
304       return A->getValue();
305     return "";
306 
307   case llvm::Triple::ppc:
308   case llvm::Triple::ppc64:
309   case llvm::Triple::ppc64le: {
310     std::string TargetCPUName = ppc::getPPCTargetCPU(Args);
311     // LLVM may default to generating code for the native CPU,
312     // but, like gcc, we default to a more generic option for
313     // each architecture. (except on Darwin)
314     if (TargetCPUName.empty() && !T.isOSDarwin()) {
315       if (T.getArch() == llvm::Triple::ppc64)
316         TargetCPUName = "ppc64";
317       else if (T.getArch() == llvm::Triple::ppc64le)
318         TargetCPUName = "ppc64le";
319       else
320         TargetCPUName = "ppc";
321     }
322     return TargetCPUName;
323   }
324 
325   case llvm::Triple::bpfel:
326   case llvm::Triple::bpfeb:
327   case llvm::Triple::sparc:
328   case llvm::Triple::sparcel:
329   case llvm::Triple::sparcv9:
330     if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
331       return A->getValue();
332     return "";
333 
334   case llvm::Triple::x86:
335   case llvm::Triple::x86_64:
336     return x86::getX86TargetCPU(Args, T);
337 
338   case llvm::Triple::hexagon:
339     return "hexagon" +
340            toolchains::HexagonToolChain::GetTargetCPUVersion(Args).str();
341 
342   case llvm::Triple::lanai:
343     return getLanaiTargetCPU(Args);
344 
345   case llvm::Triple::systemz:
346     return systemz::getSystemZTargetCPU(Args);
347 
348   case llvm::Triple::r600:
349   case llvm::Triple::amdgcn:
350     return getR600TargetGPU(Args);
351 
352   case llvm::Triple::wasm32:
353   case llvm::Triple::wasm64:
354     return getWebAssemblyTargetCPU(Args);
355   }
356 }
357 
358 unsigned tools::getLTOParallelism(const ArgList &Args, const Driver &D) {
359   unsigned Parallelism = 0;
360   Arg *LtoJobsArg = Args.getLastArg(options::OPT_flto_jobs_EQ);
361   if (LtoJobsArg &&
362       StringRef(LtoJobsArg->getValue()).getAsInteger(10, Parallelism))
363     D.Diag(diag::err_drv_invalid_int_value) << LtoJobsArg->getAsString(Args)
364                                             << LtoJobsArg->getValue();
365   return Parallelism;
366 }
367 
368 // CloudABI uses -ffunction-sections and -fdata-sections by default.
369 bool tools::isUseSeparateSections(const llvm::Triple &Triple) {
370   return Triple.getOS() == llvm::Triple::CloudABI;
371 }
372 
373 void tools::AddGoldPlugin(const ToolChain &ToolChain, const ArgList &Args,
374                           ArgStringList &CmdArgs, const InputInfo &Output,
375                           const InputInfo &Input, bool IsThinLTO) {
376   // Tell the linker to load the plugin. This has to come before AddLinkerInputs
377   // as gold requires -plugin to come before any -plugin-opt that -Wl might
378   // forward.
379   CmdArgs.push_back("-plugin");
380 
381 #if defined(LLVM_ON_WIN32)
382   const char *Suffix = ".dll";
383 #elif defined(__APPLE__)
384   const char *Suffix = ".dylib";
385 #else
386   const char *Suffix = ".so";
387 #endif
388 
389   SmallString<1024> Plugin;
390   llvm::sys::path::native(Twine(ToolChain.getDriver().Dir) +
391                               "/../lib" CLANG_LIBDIR_SUFFIX "/LLVMgold" +
392                               Suffix,
393                           Plugin);
394   CmdArgs.push_back(Args.MakeArgString(Plugin));
395 
396   // Try to pass driver level flags relevant to LTO code generation down to
397   // the plugin.
398 
399   // Handle flags for selecting CPU variants.
400   std::string CPU = getCPUName(Args, ToolChain.getTriple());
401   if (!CPU.empty())
402     CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=mcpu=") + CPU));
403 
404   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
405     StringRef OOpt;
406     if (A->getOption().matches(options::OPT_O4) ||
407         A->getOption().matches(options::OPT_Ofast))
408       OOpt = "3";
409     else if (A->getOption().matches(options::OPT_O))
410       OOpt = A->getValue();
411     else if (A->getOption().matches(options::OPT_O0))
412       OOpt = "0";
413     if (!OOpt.empty())
414       CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=O") + OOpt));
415   }
416 
417   if (IsThinLTO)
418     CmdArgs.push_back("-plugin-opt=thinlto");
419 
420   if (unsigned Parallelism = getLTOParallelism(Args, ToolChain.getDriver()))
421     CmdArgs.push_back(
422         Args.MakeArgString("-plugin-opt=jobs=" + Twine(Parallelism)));
423 
424   // If an explicit debugger tuning argument appeared, pass it along.
425   if (Arg *A = Args.getLastArg(options::OPT_gTune_Group,
426                                options::OPT_ggdbN_Group)) {
427     if (A->getOption().matches(options::OPT_glldb))
428       CmdArgs.push_back("-plugin-opt=-debugger-tune=lldb");
429     else if (A->getOption().matches(options::OPT_gsce))
430       CmdArgs.push_back("-plugin-opt=-debugger-tune=sce");
431     else
432       CmdArgs.push_back("-plugin-opt=-debugger-tune=gdb");
433   }
434 
435   bool UseSeparateSections =
436       isUseSeparateSections(ToolChain.getEffectiveTriple());
437 
438   if (Args.hasFlag(options::OPT_ffunction_sections,
439                    options::OPT_fno_function_sections, UseSeparateSections)) {
440     CmdArgs.push_back("-plugin-opt=-function-sections");
441   }
442 
443   if (Args.hasFlag(options::OPT_fdata_sections, options::OPT_fno_data_sections,
444                    UseSeparateSections)) {
445     CmdArgs.push_back("-plugin-opt=-data-sections");
446   }
447 
448   if (Arg *A = getLastProfileSampleUseArg(Args)) {
449     StringRef FName = A->getValue();
450     if (!llvm::sys::fs::exists(FName))
451       ToolChain.getDriver().Diag(diag::err_drv_no_such_file) << FName;
452     else
453       CmdArgs.push_back(
454           Args.MakeArgString(Twine("-plugin-opt=sample-profile=") + FName));
455   }
456 
457   // Need this flag to turn on new pass manager via Gold plugin.
458   if (Args.hasFlag(options::OPT_fexperimental_new_pass_manager,
459                    options::OPT_fno_experimental_new_pass_manager,
460                    /* Default */ ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER)) {
461     CmdArgs.push_back("-plugin-opt=new-pass-manager");
462   }
463 
464   // Setup statistics file output.
465   SmallString<128> StatsFile =
466       getStatsFileName(Args, Output, Input, ToolChain.getDriver());
467   if (!StatsFile.empty())
468     CmdArgs.push_back(
469         Args.MakeArgString(Twine("-plugin-opt=stats-file=") + StatsFile));
470 }
471 
472 void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
473                                  ArgStringList &CmdArgs) {
474   if (!Args.hasFlag(options::OPT_frtlib_add_rpath,
475                     options::OPT_fno_rtlib_add_rpath, false))
476     return;
477 
478   std::string CandidateRPath = TC.getArchSpecificLibPath();
479   if (TC.getVFS().exists(CandidateRPath)) {
480     CmdArgs.push_back("-rpath");
481     CmdArgs.push_back(Args.MakeArgString(CandidateRPath.c_str()));
482   }
483 }
484 
485 bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
486                              const ArgList &Args, bool IsOffloadingHost,
487                              bool GompNeedsRT) {
488   if (!Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
489                     options::OPT_fno_openmp, false))
490     return false;
491 
492   switch (TC.getDriver().getOpenMPRuntime(Args)) {
493   case Driver::OMPRT_OMP:
494     CmdArgs.push_back("-lomp");
495     break;
496   case Driver::OMPRT_GOMP:
497     CmdArgs.push_back("-lgomp");
498 
499     if (GompNeedsRT)
500       CmdArgs.push_back("-lrt");
501     break;
502   case Driver::OMPRT_IOMP5:
503     CmdArgs.push_back("-liomp5");
504     break;
505   case Driver::OMPRT_Unknown:
506     // Already diagnosed.
507     return false;
508   }
509 
510   if (IsOffloadingHost)
511     CmdArgs.push_back("-lomptarget");
512 
513   addArchSpecificRPath(TC, Args, CmdArgs);
514 
515   return true;
516 }
517 
518 static void addSanitizerRuntime(const ToolChain &TC, const ArgList &Args,
519                                 ArgStringList &CmdArgs, StringRef Sanitizer,
520                                 bool IsShared, bool IsWhole) {
521   // Wrap any static runtimes that must be forced into executable in
522   // whole-archive.
523   if (IsWhole) CmdArgs.push_back("--whole-archive");
524   CmdArgs.push_back(TC.getCompilerRTArgString(Args, Sanitizer, IsShared));
525   if (IsWhole) CmdArgs.push_back("--no-whole-archive");
526 
527   if (IsShared) {
528     addArchSpecificRPath(TC, Args, CmdArgs);
529   }
530 }
531 
532 // Tries to use a file with the list of dynamic symbols that need to be exported
533 // from the runtime library. Returns true if the file was found.
534 static bool addSanitizerDynamicList(const ToolChain &TC, const ArgList &Args,
535                                     ArgStringList &CmdArgs,
536                                     StringRef Sanitizer) {
537   // Solaris ld defaults to --export-dynamic behaviour but doesn't support
538   // the option, so don't try to pass it.
539   if (TC.getTriple().getOS() == llvm::Triple::Solaris)
540     return true;
541   SmallString<128> SanRT(TC.getCompilerRT(Args, Sanitizer));
542   if (llvm::sys::fs::exists(SanRT + ".syms")) {
543     CmdArgs.push_back(Args.MakeArgString("--dynamic-list=" + SanRT + ".syms"));
544     return true;
545   }
546   return false;
547 }
548 
549 void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,
550                                      ArgStringList &CmdArgs) {
551   // Force linking against the system libraries sanitizers depends on
552   // (see PR15823 why this is necessary).
553   CmdArgs.push_back("--no-as-needed");
554   // There's no libpthread or librt on RTEMS.
555   if (TC.getTriple().getOS() != llvm::Triple::RTEMS) {
556     CmdArgs.push_back("-lpthread");
557     if (TC.getTriple().getOS() != llvm::Triple::OpenBSD)
558       CmdArgs.push_back("-lrt");
559   }
560   CmdArgs.push_back("-lm");
561   // There's no libdl on all OSes.
562   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
563       TC.getTriple().getOS() != llvm::Triple::NetBSD &&
564       TC.getTriple().getOS() != llvm::Triple::OpenBSD &&
565       TC.getTriple().getOS() != llvm::Triple::RTEMS)
566     CmdArgs.push_back("-ldl");
567   // Required for backtrace on some OSes
568   if (TC.getTriple().getOS() == llvm::Triple::NetBSD ||
569       TC.getTriple().getOS() == llvm::Triple::FreeBSD)
570     CmdArgs.push_back("-lexecinfo");
571 }
572 
573 static void
574 collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
575                          SmallVectorImpl<StringRef> &SharedRuntimes,
576                          SmallVectorImpl<StringRef> &StaticRuntimes,
577                          SmallVectorImpl<StringRef> &NonWholeStaticRuntimes,
578                          SmallVectorImpl<StringRef> &HelperStaticRuntimes,
579                          SmallVectorImpl<StringRef> &RequiredSymbols) {
580   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
581   // Collect shared runtimes.
582   if (SanArgs.needsSharedRt()) {
583     if (SanArgs.needsAsanRt()) {
584       SharedRuntimes.push_back("asan");
585       if (!Args.hasArg(options::OPT_shared) && !TC.getTriple().isAndroid())
586         HelperStaticRuntimes.push_back("asan-preinit");
587     }
588     if (SanArgs.needsUbsanRt()) {
589       if (SanArgs.requiresMinimalRuntime()) {
590         SharedRuntimes.push_back("ubsan_minimal");
591       } else {
592         SharedRuntimes.push_back("ubsan_standalone");
593       }
594     }
595     if (SanArgs.needsScudoRt())
596       SharedRuntimes.push_back("scudo");
597     if (SanArgs.needsHwasanRt())
598       SharedRuntimes.push_back("hwasan");
599   }
600 
601   // The stats_client library is also statically linked into DSOs.
602   if (SanArgs.needsStatsRt())
603     StaticRuntimes.push_back("stats_client");
604 
605   // Collect static runtimes.
606   if (Args.hasArg(options::OPT_shared) || SanArgs.needsSharedRt()) {
607     // Don't link static runtimes into DSOs or if -shared-libasan.
608     return;
609   }
610   if (SanArgs.needsAsanRt()) {
611     StaticRuntimes.push_back("asan");
612     if (SanArgs.linkCXXRuntimes())
613       StaticRuntimes.push_back("asan_cxx");
614   }
615 
616   if (SanArgs.needsHwasanRt()) {
617     StaticRuntimes.push_back("hwasan");
618     if (SanArgs.linkCXXRuntimes())
619       StaticRuntimes.push_back("hwasan_cxx");
620   }
621   if (SanArgs.needsDfsanRt())
622     StaticRuntimes.push_back("dfsan");
623   if (SanArgs.needsLsanRt())
624     StaticRuntimes.push_back("lsan");
625   if (SanArgs.needsMsanRt()) {
626     StaticRuntimes.push_back("msan");
627     if (SanArgs.linkCXXRuntimes())
628       StaticRuntimes.push_back("msan_cxx");
629   }
630   if (SanArgs.needsTsanRt()) {
631     StaticRuntimes.push_back("tsan");
632     if (SanArgs.linkCXXRuntimes())
633       StaticRuntimes.push_back("tsan_cxx");
634   }
635   if (SanArgs.needsUbsanRt()) {
636     if (SanArgs.requiresMinimalRuntime()) {
637       StaticRuntimes.push_back("ubsan_minimal");
638     } else {
639       StaticRuntimes.push_back("ubsan_standalone");
640       if (SanArgs.linkCXXRuntimes())
641         StaticRuntimes.push_back("ubsan_standalone_cxx");
642     }
643   }
644   if (SanArgs.needsSafeStackRt()) {
645     NonWholeStaticRuntimes.push_back("safestack");
646     RequiredSymbols.push_back("__safestack_init");
647   }
648   if (SanArgs.needsCfiRt())
649     StaticRuntimes.push_back("cfi");
650   if (SanArgs.needsCfiDiagRt()) {
651     StaticRuntimes.push_back("cfi_diag");
652     if (SanArgs.linkCXXRuntimes())
653       StaticRuntimes.push_back("ubsan_standalone_cxx");
654   }
655   if (SanArgs.needsStatsRt()) {
656     NonWholeStaticRuntimes.push_back("stats");
657     RequiredSymbols.push_back("__sanitizer_stats_register");
658   }
659   if (SanArgs.needsEsanRt())
660     StaticRuntimes.push_back("esan");
661   if (SanArgs.needsScudoRt()) {
662     StaticRuntimes.push_back("scudo");
663     if (SanArgs.linkCXXRuntimes())
664       StaticRuntimes.push_back("scudo_cxx");
665   }
666 }
667 
668 // Should be called before we add system libraries (C++ ABI, libstdc++/libc++,
669 // C runtime, etc). Returns true if sanitizer system deps need to be linked in.
670 bool tools::addSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
671                                  ArgStringList &CmdArgs) {
672   SmallVector<StringRef, 4> SharedRuntimes, StaticRuntimes,
673       NonWholeStaticRuntimes, HelperStaticRuntimes, RequiredSymbols;
674   collectSanitizerRuntimes(TC, Args, SharedRuntimes, StaticRuntimes,
675                            NonWholeStaticRuntimes, HelperStaticRuntimes,
676                            RequiredSymbols);
677 
678   // Inject libfuzzer dependencies.
679   if (TC.getSanitizerArgs().needsFuzzer()
680       && !Args.hasArg(options::OPT_shared)) {
681 
682     addSanitizerRuntime(TC, Args, CmdArgs, "fuzzer", false, true);
683     if (!Args.hasArg(clang::driver::options::OPT_nostdlibxx))
684       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
685   }
686 
687   for (auto RT : SharedRuntimes)
688     addSanitizerRuntime(TC, Args, CmdArgs, RT, true, false);
689   for (auto RT : HelperStaticRuntimes)
690     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
691   bool AddExportDynamic = false;
692   for (auto RT : StaticRuntimes) {
693     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
694     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
695   }
696   for (auto RT : NonWholeStaticRuntimes) {
697     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, false);
698     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
699   }
700   for (auto S : RequiredSymbols) {
701     CmdArgs.push_back("-u");
702     CmdArgs.push_back(Args.MakeArgString(S));
703   }
704   // If there is a static runtime with no dynamic list, force all the symbols
705   // to be dynamic to be sure we export sanitizer interface functions.
706   if (AddExportDynamic)
707     CmdArgs.push_back("--export-dynamic");
708 
709   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
710   if (SanArgs.hasCrossDsoCfi() && !AddExportDynamic)
711     CmdArgs.push_back("-export-dynamic-symbol=__cfi_check");
712 
713   return !StaticRuntimes.empty() || !NonWholeStaticRuntimes.empty();
714 }
715 
716 bool tools::addXRayRuntime(const ToolChain&TC, const ArgList &Args, ArgStringList &CmdArgs) {
717   if (Args.hasArg(options::OPT_shared))
718     return false;
719 
720   if (TC.getXRayArgs().needsXRayRt()) {
721     CmdArgs.push_back("-whole-archive");
722     CmdArgs.push_back(TC.getCompilerRTArgString(Args, "xray", false));
723     for (const auto &Mode : TC.getXRayArgs().modeList())
724       CmdArgs.push_back(TC.getCompilerRTArgString(Args, Mode, false));
725     CmdArgs.push_back("-no-whole-archive");
726     return true;
727   }
728 
729   return false;
730 }
731 
732 void tools::linkXRayRuntimeDeps(const ToolChain &TC, ArgStringList &CmdArgs) {
733   CmdArgs.push_back("--no-as-needed");
734   CmdArgs.push_back("-lpthread");
735   if (TC.getTriple().getOS() != llvm::Triple::OpenBSD)
736     CmdArgs.push_back("-lrt");
737   CmdArgs.push_back("-lm");
738 
739   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
740       TC.getTriple().getOS() != llvm::Triple::NetBSD &&
741       TC.getTriple().getOS() != llvm::Triple::OpenBSD)
742     CmdArgs.push_back("-ldl");
743 }
744 
745 bool tools::areOptimizationsEnabled(const ArgList &Args) {
746   // Find the last -O arg and see if it is non-zero.
747   if (Arg *A = Args.getLastArg(options::OPT_O_Group))
748     return !A->getOption().matches(options::OPT_O0);
749   // Defaults to -O0.
750   return false;
751 }
752 
753 const char *tools::SplitDebugName(const ArgList &Args, const InputInfo &Input) {
754   Arg *FinalOutput = Args.getLastArg(options::OPT_o);
755   if (FinalOutput && Args.hasArg(options::OPT_c)) {
756     SmallString<128> T(FinalOutput->getValue());
757     llvm::sys::path::replace_extension(T, "dwo");
758     return Args.MakeArgString(T);
759   } else {
760     // Use the compilation dir.
761     SmallString<128> T(
762         Args.getLastArgValue(options::OPT_fdebug_compilation_dir));
763     SmallString<128> F(llvm::sys::path::stem(Input.getBaseInput()));
764     llvm::sys::path::replace_extension(F, "dwo");
765     T += F;
766     return Args.MakeArgString(F);
767   }
768 }
769 
770 void tools::SplitDebugInfo(const ToolChain &TC, Compilation &C, const Tool &T,
771                            const JobAction &JA, const ArgList &Args,
772                            const InputInfo &Output, const char *OutFile) {
773   ArgStringList ExtractArgs;
774   ExtractArgs.push_back("--extract-dwo");
775 
776   ArgStringList StripArgs;
777   StripArgs.push_back("--strip-dwo");
778 
779   // Grabbing the output of the earlier compile step.
780   StripArgs.push_back(Output.getFilename());
781   ExtractArgs.push_back(Output.getFilename());
782   ExtractArgs.push_back(OutFile);
783 
784   const char *Exec =
785       Args.MakeArgString(TC.GetProgramPath(CLANG_DEFAULT_OBJCOPY));
786   InputInfo II(types::TY_Object, Output.getFilename(), Output.getFilename());
787 
788   // First extract the dwo sections.
789   C.addCommand(llvm::make_unique<Command>(JA, T, Exec, ExtractArgs, II));
790 
791   // Then remove them from the original .o file.
792   C.addCommand(llvm::make_unique<Command>(JA, T, Exec, StripArgs, II));
793 }
794 
795 // Claim options we don't want to warn if they are unused. We do this for
796 // options that build systems might add but are unused when assembling or only
797 // running the preprocessor for example.
798 void tools::claimNoWarnArgs(const ArgList &Args) {
799   // Don't warn about unused -f(no-)?lto.  This can happen when we're
800   // preprocessing, precompiling or assembling.
801   Args.ClaimAllArgs(options::OPT_flto_EQ);
802   Args.ClaimAllArgs(options::OPT_flto);
803   Args.ClaimAllArgs(options::OPT_fno_lto);
804 }
805 
806 Arg *tools::getLastProfileUseArg(const ArgList &Args) {
807   auto *ProfileUseArg = Args.getLastArg(
808       options::OPT_fprofile_instr_use, options::OPT_fprofile_instr_use_EQ,
809       options::OPT_fprofile_use, options::OPT_fprofile_use_EQ,
810       options::OPT_fno_profile_instr_use);
811 
812   if (ProfileUseArg &&
813       ProfileUseArg->getOption().matches(options::OPT_fno_profile_instr_use))
814     ProfileUseArg = nullptr;
815 
816   return ProfileUseArg;
817 }
818 
819 Arg *tools::getLastProfileSampleUseArg(const ArgList &Args) {
820   auto *ProfileSampleUseArg = Args.getLastArg(
821       options::OPT_fprofile_sample_use, options::OPT_fprofile_sample_use_EQ,
822       options::OPT_fauto_profile, options::OPT_fauto_profile_EQ,
823       options::OPT_fno_profile_sample_use, options::OPT_fno_auto_profile);
824 
825   if (ProfileSampleUseArg &&
826       (ProfileSampleUseArg->getOption().matches(
827            options::OPT_fno_profile_sample_use) ||
828        ProfileSampleUseArg->getOption().matches(options::OPT_fno_auto_profile)))
829     return nullptr;
830 
831   return Args.getLastArg(options::OPT_fprofile_sample_use_EQ,
832                          options::OPT_fauto_profile_EQ);
833 }
834 
835 /// Parses the various -fpic/-fPIC/-fpie/-fPIE arguments.  Then,
836 /// smooshes them together with platform defaults, to decide whether
837 /// this compile should be using PIC mode or not. Returns a tuple of
838 /// (RelocationModel, PICLevel, IsPIE).
839 std::tuple<llvm::Reloc::Model, unsigned, bool>
840 tools::ParsePICArgs(const ToolChain &ToolChain, const ArgList &Args) {
841   const llvm::Triple &EffectiveTriple = ToolChain.getEffectiveTriple();
842   const llvm::Triple &Triple = ToolChain.getTriple();
843 
844   bool PIE = ToolChain.isPIEDefault();
845   bool PIC = PIE || ToolChain.isPICDefault();
846   // The Darwin/MachO default to use PIC does not apply when using -static.
847   if (Triple.isOSBinFormatMachO() && Args.hasArg(options::OPT_static))
848     PIE = PIC = false;
849   bool IsPICLevelTwo = PIC;
850 
851   bool KernelOrKext =
852       Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
853 
854   // Android-specific defaults for PIC/PIE
855   if (Triple.isAndroid()) {
856     switch (Triple.getArch()) {
857     case llvm::Triple::arm:
858     case llvm::Triple::armeb:
859     case llvm::Triple::thumb:
860     case llvm::Triple::thumbeb:
861     case llvm::Triple::aarch64:
862     case llvm::Triple::mips:
863     case llvm::Triple::mipsel:
864     case llvm::Triple::mips64:
865     case llvm::Triple::mips64el:
866       PIC = true; // "-fpic"
867       break;
868 
869     case llvm::Triple::x86:
870     case llvm::Triple::x86_64:
871       PIC = true; // "-fPIC"
872       IsPICLevelTwo = true;
873       break;
874 
875     default:
876       break;
877     }
878   }
879 
880   // OpenBSD-specific defaults for PIE
881   if (Triple.getOS() == llvm::Triple::OpenBSD) {
882     switch (ToolChain.getArch()) {
883     case llvm::Triple::arm:
884     case llvm::Triple::aarch64:
885     case llvm::Triple::mips64:
886     case llvm::Triple::mips64el:
887     case llvm::Triple::x86:
888     case llvm::Triple::x86_64:
889       IsPICLevelTwo = false; // "-fpie"
890       break;
891 
892     case llvm::Triple::ppc:
893     case llvm::Triple::sparc:
894     case llvm::Triple::sparcel:
895     case llvm::Triple::sparcv9:
896       IsPICLevelTwo = true; // "-fPIE"
897       break;
898 
899     default:
900       break;
901     }
902   }
903 
904   // AMDGPU-specific defaults for PIC.
905   if (Triple.getArch() == llvm::Triple::amdgcn)
906     PIC = true;
907 
908   // The last argument relating to either PIC or PIE wins, and no
909   // other argument is used. If the last argument is any flavor of the
910   // '-fno-...' arguments, both PIC and PIE are disabled. Any PIE
911   // option implicitly enables PIC at the same level.
912   Arg *LastPICArg = Args.getLastArg(options::OPT_fPIC, options::OPT_fno_PIC,
913                                     options::OPT_fpic, options::OPT_fno_pic,
914                                     options::OPT_fPIE, options::OPT_fno_PIE,
915                                     options::OPT_fpie, options::OPT_fno_pie);
916   if (Triple.isOSWindows() && LastPICArg &&
917       LastPICArg ==
918           Args.getLastArg(options::OPT_fPIC, options::OPT_fpic,
919                           options::OPT_fPIE, options::OPT_fpie)) {
920     ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
921         << LastPICArg->getSpelling() << Triple.str();
922     if (Triple.getArch() == llvm::Triple::x86_64)
923       return std::make_tuple(llvm::Reloc::PIC_, 2U, false);
924     return std::make_tuple(llvm::Reloc::Static, 0U, false);
925   }
926 
927   // Check whether the tool chain trumps the PIC-ness decision. If the PIC-ness
928   // is forced, then neither PIC nor PIE flags will have no effect.
929   if (!ToolChain.isPICDefaultForced()) {
930     if (LastPICArg) {
931       Option O = LastPICArg->getOption();
932       if (O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic) ||
933           O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie)) {
934         PIE = O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie);
935         PIC =
936             PIE || O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic);
937         IsPICLevelTwo =
938             O.matches(options::OPT_fPIE) || O.matches(options::OPT_fPIC);
939       } else {
940         PIE = PIC = false;
941         if (EffectiveTriple.isPS4CPU()) {
942           Arg *ModelArg = Args.getLastArg(options::OPT_mcmodel_EQ);
943           StringRef Model = ModelArg ? ModelArg->getValue() : "";
944           if (Model != "kernel") {
945             PIC = true;
946             ToolChain.getDriver().Diag(diag::warn_drv_ps4_force_pic)
947                 << LastPICArg->getSpelling();
948           }
949         }
950       }
951     }
952   }
953 
954   // Introduce a Darwin and PS4-specific hack. If the default is PIC, but the
955   // PIC level would've been set to level 1, force it back to level 2 PIC
956   // instead.
957   if (PIC && (Triple.isOSDarwin() || EffectiveTriple.isPS4CPU()))
958     IsPICLevelTwo |= ToolChain.isPICDefault();
959 
960   // This kernel flags are a trump-card: they will disable PIC/PIE
961   // generation, independent of the argument order.
962   if (KernelOrKext &&
963       ((!EffectiveTriple.isiOS() || EffectiveTriple.isOSVersionLT(6)) &&
964        !EffectiveTriple.isWatchOS()))
965     PIC = PIE = false;
966 
967   if (Arg *A = Args.getLastArg(options::OPT_mdynamic_no_pic)) {
968     // This is a very special mode. It trumps the other modes, almost no one
969     // uses it, and it isn't even valid on any OS but Darwin.
970     if (!Triple.isOSDarwin())
971       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
972           << A->getSpelling() << Triple.str();
973 
974     // FIXME: Warn when this flag trumps some other PIC or PIE flag.
975 
976     // Only a forced PIC mode can cause the actual compile to have PIC defines
977     // etc., no flags are sufficient. This behavior was selected to closely
978     // match that of llvm-gcc and Apple GCC before that.
979     PIC = ToolChain.isPICDefault() && ToolChain.isPICDefaultForced();
980 
981     return std::make_tuple(llvm::Reloc::DynamicNoPIC, PIC ? 2U : 0U, false);
982   }
983 
984   bool EmbeddedPISupported;
985   switch (Triple.getArch()) {
986     case llvm::Triple::arm:
987     case llvm::Triple::armeb:
988     case llvm::Triple::thumb:
989     case llvm::Triple::thumbeb:
990       EmbeddedPISupported = true;
991       break;
992     default:
993       EmbeddedPISupported = false;
994       break;
995   }
996 
997   bool ROPI = false, RWPI = false;
998   Arg* LastROPIArg = Args.getLastArg(options::OPT_fropi, options::OPT_fno_ropi);
999   if (LastROPIArg && LastROPIArg->getOption().matches(options::OPT_fropi)) {
1000     if (!EmbeddedPISupported)
1001       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
1002           << LastROPIArg->getSpelling() << Triple.str();
1003     ROPI = true;
1004   }
1005   Arg *LastRWPIArg = Args.getLastArg(options::OPT_frwpi, options::OPT_fno_rwpi);
1006   if (LastRWPIArg && LastRWPIArg->getOption().matches(options::OPT_frwpi)) {
1007     if (!EmbeddedPISupported)
1008       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
1009           << LastRWPIArg->getSpelling() << Triple.str();
1010     RWPI = true;
1011   }
1012 
1013   // ROPI and RWPI are not compatible with PIC or PIE.
1014   if ((ROPI || RWPI) && (PIC || PIE))
1015     ToolChain.getDriver().Diag(diag::err_drv_ropi_rwpi_incompatible_with_pic);
1016 
1017   if (Triple.getArch() == llvm::Triple::mips ||
1018        Triple.getArch() == llvm::Triple::mipsel ||
1019        Triple.getArch() == llvm::Triple::mips64 ||
1020        Triple.getArch() == llvm::Triple::mips64el) {
1021     // When targettng MIPS with -mno-abicalls, it's always static.
1022     if(Args.hasArg(options::OPT_mno_abicalls))
1023       return std::make_tuple(llvm::Reloc::Static, 0U, false);
1024     // Unlike other architectures, MIPS, even with -fPIC/-mxgot/multigot,
1025     // does not use PIC level 2 for historical reasons.
1026     IsPICLevelTwo = false;
1027   }
1028 
1029   if (PIC)
1030     return std::make_tuple(llvm::Reloc::PIC_, IsPICLevelTwo ? 2U : 1U, PIE);
1031 
1032   llvm::Reloc::Model RelocM = llvm::Reloc::Static;
1033   if (ROPI && RWPI)
1034     RelocM = llvm::Reloc::ROPI_RWPI;
1035   else if (ROPI)
1036     RelocM = llvm::Reloc::ROPI;
1037   else if (RWPI)
1038     RelocM = llvm::Reloc::RWPI;
1039 
1040   return std::make_tuple(RelocM, 0U, false);
1041 }
1042 
1043 // `-falign-functions` indicates that the functions should be aligned to a
1044 // 16-byte boundary.
1045 //
1046 // `-falign-functions=1` is the same as `-fno-align-functions`.
1047 //
1048 // The scalar `n` in `-falign-functions=n` must be an integral value between
1049 // [0, 65536].  If the value is not a power-of-two, it will be rounded up to
1050 // the nearest power-of-two.
1051 //
1052 // If we return `0`, the frontend will default to the backend's preferred
1053 // alignment.
1054 //
1055 // NOTE: icc only allows values between [0, 4096].  icc uses `-falign-functions`
1056 // to mean `-falign-functions=16`.  GCC defaults to the backend's preferred
1057 // alignment.  For unaligned functions, we default to the backend's preferred
1058 // alignment.
1059 unsigned tools::ParseFunctionAlignment(const ToolChain &TC,
1060                                        const ArgList &Args) {
1061   const Arg *A = Args.getLastArg(options::OPT_falign_functions,
1062                                  options::OPT_falign_functions_EQ,
1063                                  options::OPT_fno_align_functions);
1064   if (!A || A->getOption().matches(options::OPT_fno_align_functions))
1065     return 0;
1066 
1067   if (A->getOption().matches(options::OPT_falign_functions))
1068     return 0;
1069 
1070   unsigned Value = 0;
1071   if (StringRef(A->getValue()).getAsInteger(10, Value) || Value > 65536)
1072     TC.getDriver().Diag(diag::err_drv_invalid_int_value)
1073         << A->getAsString(Args) << A->getValue();
1074   return Value ? llvm::Log2_32_Ceil(std::min(Value, 65536u)) : Value;
1075 }
1076 
1077 void tools::AddAssemblerKPIC(const ToolChain &ToolChain, const ArgList &Args,
1078                              ArgStringList &CmdArgs) {
1079   llvm::Reloc::Model RelocationModel;
1080   unsigned PICLevel;
1081   bool IsPIE;
1082   std::tie(RelocationModel, PICLevel, IsPIE) = ParsePICArgs(ToolChain, Args);
1083 
1084   if (RelocationModel != llvm::Reloc::Static)
1085     CmdArgs.push_back("-KPIC");
1086 }
1087 
1088 /// \brief Determine whether Objective-C automated reference counting is
1089 /// enabled.
1090 bool tools::isObjCAutoRefCount(const ArgList &Args) {
1091   return Args.hasFlag(options::OPT_fobjc_arc, options::OPT_fno_objc_arc, false);
1092 }
1093 
1094 static void AddLibgcc(const llvm::Triple &Triple, const Driver &D,
1095                       ArgStringList &CmdArgs, const ArgList &Args) {
1096   bool isAndroid = Triple.isAndroid();
1097   bool isCygMing = Triple.isOSCygMing();
1098   bool IsIAMCU = Triple.isOSIAMCU();
1099   bool StaticLibgcc = Args.hasArg(options::OPT_static_libgcc) ||
1100                       Args.hasArg(options::OPT_static);
1101   if (!D.CCCIsCXX())
1102     CmdArgs.push_back("-lgcc");
1103 
1104   if (StaticLibgcc || isAndroid) {
1105     if (D.CCCIsCXX())
1106       CmdArgs.push_back("-lgcc");
1107   } else {
1108     if (!D.CCCIsCXX() && !isCygMing)
1109       CmdArgs.push_back("--as-needed");
1110     CmdArgs.push_back("-lgcc_s");
1111     if (!D.CCCIsCXX() && !isCygMing)
1112       CmdArgs.push_back("--no-as-needed");
1113   }
1114 
1115   if (StaticLibgcc && !isAndroid && !IsIAMCU)
1116     CmdArgs.push_back("-lgcc_eh");
1117   else if (!Args.hasArg(options::OPT_shared) && D.CCCIsCXX())
1118     CmdArgs.push_back("-lgcc");
1119 
1120   // According to Android ABI, we have to link with libdl if we are
1121   // linking with non-static libgcc.
1122   //
1123   // NOTE: This fixes a link error on Android MIPS as well.  The non-static
1124   // libgcc for MIPS relies on _Unwind_Find_FDE and dl_iterate_phdr from libdl.
1125   if (isAndroid && !StaticLibgcc)
1126     CmdArgs.push_back("-ldl");
1127 }
1128 
1129 void tools::AddRunTimeLibs(const ToolChain &TC, const Driver &D,
1130                            ArgStringList &CmdArgs, const ArgList &Args) {
1131   // Make use of compiler-rt if --rtlib option is used
1132   ToolChain::RuntimeLibType RLT = TC.GetRuntimeLibType(Args);
1133 
1134   switch (RLT) {
1135   case ToolChain::RLT_CompilerRT:
1136     CmdArgs.push_back(TC.getCompilerRTArgString(Args, "builtins"));
1137     break;
1138   case ToolChain::RLT_Libgcc:
1139     // Make sure libgcc is not used under MSVC environment by default
1140     if (TC.getTriple().isKnownWindowsMSVCEnvironment()) {
1141       // Issue error diagnostic if libgcc is explicitly specified
1142       // through command line as --rtlib option argument.
1143       if (Args.hasArg(options::OPT_rtlib_EQ)) {
1144         TC.getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
1145             << Args.getLastArg(options::OPT_rtlib_EQ)->getValue() << "MSVC";
1146       }
1147     } else
1148       AddLibgcc(TC.getTriple(), D, CmdArgs, Args);
1149     break;
1150   }
1151 }
1152 
1153 /// Add OpenMP linker script arguments at the end of the argument list so that
1154 /// the fat binary is built by embedding each of the device images into the
1155 /// host. The linker script also defines a few symbols required by the code
1156 /// generation so that the images can be easily retrieved at runtime by the
1157 /// offloading library. This should be used only in tool chains that support
1158 /// linker scripts.
1159 void tools::AddOpenMPLinkerScript(const ToolChain &TC, Compilation &C,
1160                                   const InputInfo &Output,
1161                                   const InputInfoList &Inputs,
1162                                   const ArgList &Args, ArgStringList &CmdArgs,
1163                                   const JobAction &JA) {
1164 
1165   // If this is not an OpenMP host toolchain, we don't need to do anything.
1166   if (!JA.isHostOffloading(Action::OFK_OpenMP))
1167     return;
1168 
1169   // Create temporary linker script. Keep it if save-temps is enabled.
1170   const char *LKS;
1171   SmallString<256> Name = llvm::sys::path::filename(Output.getFilename());
1172   if (C.getDriver().isSaveTempsEnabled()) {
1173     llvm::sys::path::replace_extension(Name, "lk");
1174     LKS = C.getArgs().MakeArgString(Name.c_str());
1175   } else {
1176     llvm::sys::path::replace_extension(Name, "");
1177     Name = C.getDriver().GetTemporaryPath(Name, "lk");
1178     LKS = C.addTempFile(C.getArgs().MakeArgString(Name.c_str()));
1179   }
1180 
1181   // Add linker script option to the command.
1182   CmdArgs.push_back("-T");
1183   CmdArgs.push_back(LKS);
1184 
1185   // Create a buffer to write the contents of the linker script.
1186   std::string LksBuffer;
1187   llvm::raw_string_ostream LksStream(LksBuffer);
1188 
1189   // Get the OpenMP offload tool chains so that we can extract the triple
1190   // associated with each device input.
1191   auto OpenMPToolChains = C.getOffloadToolChains<Action::OFK_OpenMP>();
1192   assert(OpenMPToolChains.first != OpenMPToolChains.second &&
1193          "No OpenMP toolchains??");
1194 
1195   // Track the input file name and device triple in order to build the script,
1196   // inserting binaries in the designated sections.
1197   SmallVector<std::pair<std::string, const char *>, 8> InputBinaryInfo;
1198 
1199   // Add commands to embed target binaries. We ensure that each section and
1200   // image is 16-byte aligned. This is not mandatory, but increases the
1201   // likelihood of data to be aligned with a cache block in several main host
1202   // machines.
1203   LksStream << "/*\n";
1204   LksStream << "       OpenMP Offload Linker Script\n";
1205   LksStream << " *** Automatically generated by Clang ***\n";
1206   LksStream << "*/\n";
1207   LksStream << "TARGET(binary)\n";
1208   auto DTC = OpenMPToolChains.first;
1209   for (auto &II : Inputs) {
1210     const Action *A = II.getAction();
1211     // Is this a device linking action?
1212     if (A && isa<LinkJobAction>(A) &&
1213         A->isDeviceOffloading(Action::OFK_OpenMP)) {
1214       assert(DTC != OpenMPToolChains.second &&
1215              "More device inputs than device toolchains??");
1216       InputBinaryInfo.push_back(std::make_pair(
1217           DTC->second->getTriple().normalize(), II.getFilename()));
1218       ++DTC;
1219       LksStream << "INPUT(" << II.getFilename() << ")\n";
1220     }
1221   }
1222 
1223   assert(DTC == OpenMPToolChains.second &&
1224          "Less device inputs than device toolchains??");
1225 
1226   LksStream << "SECTIONS\n";
1227   LksStream << "{\n";
1228 
1229   // Put each target binary into a separate section.
1230   for (const auto &BI : InputBinaryInfo) {
1231     LksStream << "  .omp_offloading." << BI.first << " :\n";
1232     LksStream << "  ALIGN(0x10)\n";
1233     LksStream << "  {\n";
1234     LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_start." << BI.first
1235               << " = .);\n";
1236     LksStream << "    " << BI.second << "\n";
1237     LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_end." << BI.first
1238               << " = .);\n";
1239     LksStream << "  }\n";
1240   }
1241 
1242   // Add commands to define host entries begin and end. We use 1-byte subalign
1243   // so that the linker does not add any padding and the elements in this
1244   // section form an array.
1245   LksStream << "  .omp_offloading.entries :\n";
1246   LksStream << "  ALIGN(0x10)\n";
1247   LksStream << "  SUBALIGN(0x01)\n";
1248   LksStream << "  {\n";
1249   LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_begin = .);\n";
1250   LksStream << "    *(.omp_offloading.entries)\n";
1251   LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_end = .);\n";
1252   LksStream << "  }\n";
1253   LksStream << "}\n";
1254   LksStream << "INSERT BEFORE .data\n";
1255   LksStream.flush();
1256 
1257   // Dump the contents of the linker script if the user requested that. We
1258   // support this option to enable testing of behavior with -###.
1259   if (C.getArgs().hasArg(options::OPT_fopenmp_dump_offload_linker_script))
1260     llvm::errs() << LksBuffer;
1261 
1262   // If this is a dry run, do not create the linker script file.
1263   if (C.getArgs().hasArg(options::OPT__HASH_HASH_HASH))
1264     return;
1265 
1266   // Open script file and write the contents.
1267   std::error_code EC;
1268   llvm::raw_fd_ostream Lksf(LKS, EC, llvm::sys::fs::F_None);
1269 
1270   if (EC) {
1271     C.getDriver().Diag(clang::diag::err_unable_to_make_temp) << EC.message();
1272     return;
1273   }
1274 
1275   Lksf << LksBuffer;
1276 }
1277 
1278 SmallString<128> tools::getStatsFileName(const llvm::opt::ArgList &Args,
1279                                          const InputInfo &Output,
1280                                          const InputInfo &Input,
1281                                          const Driver &D) {
1282   const Arg *A = Args.getLastArg(options::OPT_save_stats_EQ);
1283   if (!A)
1284     return {};
1285 
1286   StringRef SaveStats = A->getValue();
1287   SmallString<128> StatsFile;
1288   if (SaveStats == "obj" && Output.isFilename()) {
1289     StatsFile.assign(Output.getFilename());
1290     llvm::sys::path::remove_filename(StatsFile);
1291   } else if (SaveStats != "cwd") {
1292     D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << SaveStats;
1293     return {};
1294   }
1295 
1296   StringRef BaseName = llvm::sys::path::filename(Input.getBaseInput());
1297   llvm::sys::path::append(StatsFile, BaseName);
1298   llvm::sys::path::replace_extension(StatsFile, "stats");
1299   return StatsFile;
1300 }
1301