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 "InputInfo.h"
12 #include "Hexagon.h"
13 #include "Arch/AArch64.h"
14 #include "Arch/ARM.h"
15 #include "Arch/Mips.h"
16 #include "Arch/PPC.h"
17 #include "Arch/SystemZ.h"
18 #include "Arch/X86.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 "llvm/ADT/STLExtras.h"
35 #include "llvm/ADT/SmallString.h"
36 #include "llvm/ADT/StringExtras.h"
37 #include "llvm/ADT/StringSwitch.h"
38 #include "llvm/ADT/Twine.h"
39 #include "llvm/Option/Arg.h"
40 #include "llvm/Option/ArgList.h"
41 #include "llvm/Option/Option.h"
42 #include "llvm/Support/CodeGen.h"
43 #include "llvm/Support/Compression.h"
44 #include "llvm/Support/ErrorHandling.h"
45 #include "llvm/Support/FileSystem.h"
46 #include "llvm/Support/Host.h"
47 #include "llvm/Support/Path.h"
48 #include "llvm/Support/Process.h"
49 #include "llvm/Support/Program.h"
50 #include "llvm/Support/ScopedPrinter.h"
51 #include "llvm/Support/TargetParser.h"
52 #include "llvm/Support/YAMLParser.h"
53 
54 using namespace clang::driver;
55 using namespace clang::driver::tools;
56 using namespace clang;
57 using namespace llvm::opt;
58 
59 void tools::addPathIfExists(const Driver &D, const Twine &Path,
60                             ToolChain::path_list &Paths) {
61   if (D.getVFS().exists(Path))
62     Paths.push_back(Path.str());
63 }
64 
65 void tools::handleTargetFeaturesGroup(const ArgList &Args,
66                                       std::vector<StringRef> &Features,
67                                       OptSpecifier Group) {
68   for (const Arg *A : Args.filtered(Group)) {
69     StringRef Name = A->getOption().getName();
70     A->claim();
71 
72     // Skip over "-m".
73     assert(Name.startswith("m") && "Invalid feature name.");
74     Name = Name.substr(1);
75 
76     bool IsNegative = Name.startswith("no-");
77     if (IsNegative)
78       Name = Name.substr(3);
79     Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name));
80   }
81 }
82 
83 void tools::addDirectoryList(const ArgList &Args, ArgStringList &CmdArgs,
84                              const char *ArgName, const char *EnvVar) {
85   const char *DirList = ::getenv(EnvVar);
86   bool CombinedArg = false;
87 
88   if (!DirList)
89     return; // Nothing to do.
90 
91   StringRef Name(ArgName);
92   if (Name.equals("-I") || Name.equals("-L"))
93     CombinedArg = true;
94 
95   StringRef Dirs(DirList);
96   if (Dirs.empty()) // Empty string should not add '.'.
97     return;
98 
99   StringRef::size_type Delim;
100   while ((Delim = Dirs.find(llvm::sys::EnvPathSeparator)) != StringRef::npos) {
101     if (Delim == 0) { // Leading colon.
102       if (CombinedArg) {
103         CmdArgs.push_back(Args.MakeArgString(std::string(ArgName) + "."));
104       } else {
105         CmdArgs.push_back(ArgName);
106         CmdArgs.push_back(".");
107       }
108     } else {
109       if (CombinedArg) {
110         CmdArgs.push_back(
111             Args.MakeArgString(std::string(ArgName) + Dirs.substr(0, Delim)));
112       } else {
113         CmdArgs.push_back(ArgName);
114         CmdArgs.push_back(Args.MakeArgString(Dirs.substr(0, Delim)));
115       }
116     }
117     Dirs = Dirs.substr(Delim + 1);
118   }
119 
120   if (Dirs.empty()) { // Trailing colon.
121     if (CombinedArg) {
122       CmdArgs.push_back(Args.MakeArgString(std::string(ArgName) + "."));
123     } else {
124       CmdArgs.push_back(ArgName);
125       CmdArgs.push_back(".");
126     }
127   } else { // Add the last path.
128     if (CombinedArg) {
129       CmdArgs.push_back(Args.MakeArgString(std::string(ArgName) + Dirs));
130     } else {
131       CmdArgs.push_back(ArgName);
132       CmdArgs.push_back(Args.MakeArgString(Dirs));
133     }
134   }
135 }
136 
137 void tools::AddLinkerInputs(const ToolChain &TC, const InputInfoList &Inputs,
138                             const ArgList &Args, ArgStringList &CmdArgs,
139                             const JobAction &JA) {
140   const Driver &D = TC.getDriver();
141 
142   // Add extra linker input arguments which are not treated as inputs
143   // (constructed via -Xarch_).
144   Args.AddAllArgValues(CmdArgs, options::OPT_Zlinker_input);
145 
146   for (const auto &II : Inputs) {
147     // If the current tool chain refers to an OpenMP offloading host, we should
148     // ignore inputs that refer to OpenMP offloading devices - they will be
149     // embedded according to a proper linker script.
150     if (auto *IA = II.getAction())
151       if (JA.isHostOffloading(Action::OFK_OpenMP) &&
152           IA->isDeviceOffloading(Action::OFK_OpenMP))
153         continue;
154 
155     if (!TC.HasNativeLLVMSupport() && types::isLLVMIR(II.getType()))
156       // Don't try to pass LLVM inputs unless we have native support.
157       D.Diag(diag::err_drv_no_linker_llvm_support) << TC.getTripleString();
158 
159     // Add filenames immediately.
160     if (II.isFilename()) {
161       CmdArgs.push_back(II.getFilename());
162       continue;
163     }
164 
165     // Otherwise, this is a linker input argument.
166     const Arg &A = II.getInputArg();
167 
168     // Handle reserved library options.
169     if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx))
170       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
171     else if (A.getOption().matches(options::OPT_Z_reserved_lib_cckext))
172       TC.AddCCKextLibArgs(Args, CmdArgs);
173     else if (A.getOption().matches(options::OPT_z)) {
174       // Pass -z prefix for gcc linker compatibility.
175       A.claim();
176       A.render(Args, CmdArgs);
177     } else {
178       A.renderAsInput(Args, CmdArgs);
179     }
180   }
181 
182   // LIBRARY_PATH - included following the user specified library paths.
183   //                and only supported on native toolchains.
184   if (!TC.isCrossCompiling()) {
185     addDirectoryList(Args, CmdArgs, "-L", "LIBRARY_PATH");
186   }
187 }
188 
189 void tools::AddTargetFeature(const ArgList &Args,
190                              std::vector<StringRef> &Features,
191                              OptSpecifier OnOpt, OptSpecifier OffOpt,
192                              StringRef FeatureName) {
193   if (Arg *A = Args.getLastArg(OnOpt, OffOpt)) {
194     if (A->getOption().matches(OnOpt))
195       Features.push_back(Args.MakeArgString("+" + FeatureName));
196     else
197       Features.push_back(Args.MakeArgString("-" + FeatureName));
198   }
199 }
200 
201 /// Get the (LLVM) name of the R600 gpu we are targeting.
202 static std::string getR600TargetGPU(const ArgList &Args) {
203   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
204     const char *GPUName = A->getValue();
205     return llvm::StringSwitch<const char *>(GPUName)
206         .Cases("rv630", "rv635", "r600")
207         .Cases("rv610", "rv620", "rs780", "rs880")
208         .Case("rv740", "rv770")
209         .Case("palm", "cedar")
210         .Cases("sumo", "sumo2", "sumo")
211         .Case("hemlock", "cypress")
212         .Case("aruba", "cayman")
213         .Default(GPUName);
214   }
215   return "";
216 }
217 
218 static std::string getNios2TargetCPU(const ArgList &Args) {
219   Arg *A = Args.getLastArg(options::OPT_mcpu_EQ);
220   if (!A)
221     A = Args.getLastArg(options::OPT_march_EQ);
222 
223   if (!A)
224     return "";
225 
226   const char *name = A->getValue();
227   return llvm::StringSwitch<const char *>(name)
228       .Case("r1", "nios2r1")
229       .Case("r2", "nios2r2")
230       .Default(name);
231 }
232 
233 static std::string getLanaiTargetCPU(const ArgList &Args) {
234   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
235     return A->getValue();
236   }
237   return "";
238 }
239 
240 /// Get the (LLVM) name of the WebAssembly cpu we are targeting.
241 static StringRef getWebAssemblyTargetCPU(const ArgList &Args) {
242   // If we have -mcpu=, use that.
243   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
244     StringRef CPU = A->getValue();
245 
246 #ifdef __wasm__
247     // Handle "native" by examining the host. "native" isn't meaningful when
248     // cross compiling, so only support this when the host is also WebAssembly.
249     if (CPU == "native")
250       return llvm::sys::getHostCPUName();
251 #endif
252 
253     return CPU;
254   }
255 
256   return "generic";
257 }
258 
259 std::string tools::getCPUName(const ArgList &Args, const llvm::Triple &T,
260                               bool FromAs) {
261   Arg *A;
262 
263   switch (T.getArch()) {
264   default:
265     return "";
266 
267   case llvm::Triple::aarch64:
268   case llvm::Triple::aarch64_be:
269     return aarch64::getAArch64TargetCPU(Args, A);
270 
271   case llvm::Triple::arm:
272   case llvm::Triple::armeb:
273   case llvm::Triple::thumb:
274   case llvm::Triple::thumbeb: {
275     StringRef MArch, MCPU;
276     arm::getARMArchCPUFromArgs(Args, MArch, MCPU, FromAs);
277     return arm::getARMTargetCPU(MCPU, MArch, T);
278   }
279 
280   case llvm::Triple::avr:
281     if (const Arg *A = Args.getLastArg(options::OPT_mmcu_EQ))
282       return A->getValue();
283     return "";
284 
285   case llvm::Triple::nios2: {
286     return getNios2TargetCPU(Args);
287   }
288 
289   case llvm::Triple::mips:
290   case llvm::Triple::mipsel:
291   case llvm::Triple::mips64:
292   case llvm::Triple::mips64el: {
293     StringRef CPUName;
294     StringRef ABIName;
295     mips::getMipsCPUAndABI(Args, T, CPUName, ABIName);
296     return CPUName;
297   }
298 
299   case llvm::Triple::nvptx:
300   case llvm::Triple::nvptx64:
301     if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
302       return A->getValue();
303     return "";
304 
305   case llvm::Triple::ppc:
306   case llvm::Triple::ppc64:
307   case llvm::Triple::ppc64le: {
308     std::string TargetCPUName = ppc::getPPCTargetCPU(Args);
309     // LLVM may default to generating code for the native CPU,
310     // but, like gcc, we default to a more generic option for
311     // each architecture. (except on Darwin)
312     if (TargetCPUName.empty() && !T.isOSDarwin()) {
313       if (T.getArch() == llvm::Triple::ppc64)
314         TargetCPUName = "ppc64";
315       else if (T.getArch() == llvm::Triple::ppc64le)
316         TargetCPUName = "ppc64le";
317       else
318         TargetCPUName = "ppc";
319     }
320     return TargetCPUName;
321   }
322 
323   case llvm::Triple::sparc:
324   case llvm::Triple::sparcel:
325   case llvm::Triple::sparcv9:
326     if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
327       return A->getValue();
328     return "";
329 
330   case llvm::Triple::x86:
331   case llvm::Triple::x86_64:
332     return x86::getX86TargetCPU(Args, T);
333 
334   case llvm::Triple::hexagon:
335     return "hexagon" +
336            toolchains::HexagonToolChain::GetTargetCPUVersion(Args).str();
337 
338   case llvm::Triple::lanai:
339     return getLanaiTargetCPU(Args);
340 
341   case llvm::Triple::systemz:
342     return systemz::getSystemZTargetCPU(Args);
343 
344   case llvm::Triple::r600:
345   case llvm::Triple::amdgcn:
346     return getR600TargetGPU(Args);
347 
348   case llvm::Triple::wasm32:
349   case llvm::Triple::wasm64:
350     return getWebAssemblyTargetCPU(Args);
351   }
352 }
353 
354 unsigned tools::getLTOParallelism(const ArgList &Args, const Driver &D) {
355   unsigned Parallelism = 0;
356   Arg *LtoJobsArg = Args.getLastArg(options::OPT_flto_jobs_EQ);
357   if (LtoJobsArg &&
358       StringRef(LtoJobsArg->getValue()).getAsInteger(10, Parallelism))
359     D.Diag(diag::err_drv_invalid_int_value) << LtoJobsArg->getAsString(Args)
360                                             << LtoJobsArg->getValue();
361   return Parallelism;
362 }
363 
364 // CloudABI and WebAssembly use -ffunction-sections and -fdata-sections by
365 // default.
366 bool tools::isUseSeparateSections(const llvm::Triple &Triple) {
367   return Triple.getOS() == llvm::Triple::CloudABI ||
368          Triple.getArch() == llvm::Triple::wasm32 ||
369          Triple.getArch() == llvm::Triple::wasm64;
370 }
371 
372 void tools::AddGoldPlugin(const ToolChain &ToolChain, const ArgList &Args,
373                           ArgStringList &CmdArgs, bool IsThinLTO,
374                           const Driver &D) {
375   // Tell the linker to load the plugin. This has to come before AddLinkerInputs
376   // as gold requires -plugin to come before any -plugin-opt that -Wl might
377   // forward.
378   CmdArgs.push_back("-plugin");
379   std::string Plugin =
380       ToolChain.getDriver().Dir + "/../lib" CLANG_LIBDIR_SUFFIX "/LLVMgold.so";
381   CmdArgs.push_back(Args.MakeArgString(Plugin));
382 
383   // Try to pass driver level flags relevant to LTO code generation down to
384   // the plugin.
385 
386   // Handle flags for selecting CPU variants.
387   std::string CPU = getCPUName(Args, ToolChain.getTriple());
388   if (!CPU.empty())
389     CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=mcpu=") + CPU));
390 
391   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
392     StringRef OOpt;
393     if (A->getOption().matches(options::OPT_O4) ||
394         A->getOption().matches(options::OPT_Ofast))
395       OOpt = "3";
396     else if (A->getOption().matches(options::OPT_O))
397       OOpt = A->getValue();
398     else if (A->getOption().matches(options::OPT_O0))
399       OOpt = "0";
400     if (!OOpt.empty())
401       CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=O") + OOpt));
402   }
403 
404   if (IsThinLTO)
405     CmdArgs.push_back("-plugin-opt=thinlto");
406 
407   if (unsigned Parallelism = getLTOParallelism(Args, D))
408     CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=jobs=") +
409                                          llvm::to_string(Parallelism)));
410 
411   // If an explicit debugger tuning argument appeared, pass it along.
412   if (Arg *A = Args.getLastArg(options::OPT_gTune_Group,
413                                options::OPT_ggdbN_Group)) {
414     if (A->getOption().matches(options::OPT_glldb))
415       CmdArgs.push_back("-plugin-opt=-debugger-tune=lldb");
416     else if (A->getOption().matches(options::OPT_gsce))
417       CmdArgs.push_back("-plugin-opt=-debugger-tune=sce");
418     else
419       CmdArgs.push_back("-plugin-opt=-debugger-tune=gdb");
420   }
421 
422   bool UseSeparateSections =
423       isUseSeparateSections(ToolChain.getEffectiveTriple());
424 
425   if (Args.hasFlag(options::OPT_ffunction_sections,
426                    options::OPT_fno_function_sections, UseSeparateSections)) {
427     CmdArgs.push_back("-plugin-opt=-function-sections");
428   }
429 
430   if (Args.hasFlag(options::OPT_fdata_sections, options::OPT_fno_data_sections,
431                    UseSeparateSections)) {
432     CmdArgs.push_back("-plugin-opt=-data-sections");
433   }
434 
435   if (Arg *A = getLastProfileSampleUseArg(Args)) {
436     StringRef FName = A->getValue();
437     if (!llvm::sys::fs::exists(FName))
438       D.Diag(diag::err_drv_no_such_file) << FName;
439     else
440       CmdArgs.push_back(
441           Args.MakeArgString(Twine("-plugin-opt=sample-profile=") + FName));
442   }
443 }
444 
445 void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
446                                  ArgStringList &CmdArgs) {
447   std::string CandidateRPath = TC.getArchSpecificLibPath();
448   if (TC.getVFS().exists(CandidateRPath)) {
449     CmdArgs.push_back("-rpath");
450     CmdArgs.push_back(Args.MakeArgString(CandidateRPath.c_str()));
451   }
452 }
453 
454 bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
455                              const ArgList &Args, bool IsOffloadingHost,
456                              bool GompNeedsRT) {
457   if (!Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
458                     options::OPT_fno_openmp, false))
459     return false;
460 
461   switch (TC.getDriver().getOpenMPRuntime(Args)) {
462   case Driver::OMPRT_OMP:
463     CmdArgs.push_back("-lomp");
464     break;
465   case Driver::OMPRT_GOMP:
466     CmdArgs.push_back("-lgomp");
467 
468     if (GompNeedsRT)
469       CmdArgs.push_back("-lrt");
470     break;
471   case Driver::OMPRT_IOMP5:
472     CmdArgs.push_back("-liomp5");
473     break;
474   case Driver::OMPRT_Unknown:
475     // Already diagnosed.
476     return false;
477   }
478 
479   if (IsOffloadingHost)
480     CmdArgs.push_back("-lomptarget");
481 
482   addArchSpecificRPath(TC, Args, CmdArgs);
483 
484   return true;
485 }
486 
487 static void addSanitizerRuntime(const ToolChain &TC, const ArgList &Args,
488                                 ArgStringList &CmdArgs, StringRef Sanitizer,
489                                 bool IsShared, bool IsWhole) {
490   // Wrap any static runtimes that must be forced into executable in
491   // whole-archive.
492   if (IsWhole) CmdArgs.push_back("-whole-archive");
493   CmdArgs.push_back(TC.getCompilerRTArgString(Args, Sanitizer, IsShared));
494   if (IsWhole) CmdArgs.push_back("-no-whole-archive");
495 
496   if (IsShared) {
497     addArchSpecificRPath(TC, Args, CmdArgs);
498   }
499 }
500 
501 // Tries to use a file with the list of dynamic symbols that need to be exported
502 // from the runtime library. Returns true if the file was found.
503 static bool addSanitizerDynamicList(const ToolChain &TC, const ArgList &Args,
504                                     ArgStringList &CmdArgs,
505                                     StringRef Sanitizer) {
506   SmallString<128> SanRT(TC.getCompilerRT(Args, Sanitizer));
507   if (llvm::sys::fs::exists(SanRT + ".syms")) {
508     CmdArgs.push_back(Args.MakeArgString("--dynamic-list=" + SanRT + ".syms"));
509     return true;
510   }
511   return false;
512 }
513 
514 void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,
515                                      ArgStringList &CmdArgs) {
516   // Force linking against the system libraries sanitizers depends on
517   // (see PR15823 why this is necessary).
518   CmdArgs.push_back("--no-as-needed");
519   // There's no libpthread or librt on RTEMS.
520   if (TC.getTriple().getOS() != llvm::Triple::RTEMS) {
521     CmdArgs.push_back("-lpthread");
522     CmdArgs.push_back("-lrt");
523   }
524   CmdArgs.push_back("-lm");
525   // There's no libdl on FreeBSD or RTEMS.
526   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
527       TC.getTriple().getOS() != llvm::Triple::NetBSD &&
528       TC.getTriple().getOS() != llvm::Triple::RTEMS)
529     CmdArgs.push_back("-ldl");
530 }
531 
532 static void
533 collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
534                          SmallVectorImpl<StringRef> &SharedRuntimes,
535                          SmallVectorImpl<StringRef> &StaticRuntimes,
536                          SmallVectorImpl<StringRef> &NonWholeStaticRuntimes,
537                          SmallVectorImpl<StringRef> &HelperStaticRuntimes,
538                          SmallVectorImpl<StringRef> &RequiredSymbols) {
539   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
540   // Collect shared runtimes.
541   if (SanArgs.needsAsanRt() && SanArgs.needsSharedAsanRt()) {
542     SharedRuntimes.push_back("asan");
543   }
544   // The stats_client library is also statically linked into DSOs.
545   if (SanArgs.needsStatsRt())
546     StaticRuntimes.push_back("stats_client");
547 
548   // Collect static runtimes.
549   if (Args.hasArg(options::OPT_shared) || TC.getTriple().isAndroid()) {
550     // Don't link static runtimes into DSOs or if compiling for Android.
551     return;
552   }
553   if (SanArgs.needsAsanRt()) {
554     if (SanArgs.needsSharedAsanRt()) {
555       HelperStaticRuntimes.push_back("asan-preinit");
556     } else {
557       StaticRuntimes.push_back("asan");
558       if (SanArgs.linkCXXRuntimes())
559         StaticRuntimes.push_back("asan_cxx");
560     }
561   }
562   if (SanArgs.needsDfsanRt())
563     StaticRuntimes.push_back("dfsan");
564   if (SanArgs.needsLsanRt())
565     StaticRuntimes.push_back("lsan");
566   if (SanArgs.needsMsanRt()) {
567     StaticRuntimes.push_back("msan");
568     if (SanArgs.linkCXXRuntimes())
569       StaticRuntimes.push_back("msan_cxx");
570   }
571   if (SanArgs.needsTsanRt()) {
572     StaticRuntimes.push_back("tsan");
573     if (SanArgs.linkCXXRuntimes())
574       StaticRuntimes.push_back("tsan_cxx");
575   }
576   if (SanArgs.needsUbsanRt()) {
577     StaticRuntimes.push_back("ubsan_standalone");
578     if (SanArgs.linkCXXRuntimes())
579       StaticRuntimes.push_back("ubsan_standalone_cxx");
580   }
581   if (SanArgs.needsSafeStackRt()) {
582     NonWholeStaticRuntimes.push_back("safestack");
583     RequiredSymbols.push_back("__safestack_init");
584   }
585   if (SanArgs.needsCfiRt())
586     StaticRuntimes.push_back("cfi");
587   if (SanArgs.needsCfiDiagRt()) {
588     StaticRuntimes.push_back("cfi_diag");
589     if (SanArgs.linkCXXRuntimes())
590       StaticRuntimes.push_back("ubsan_standalone_cxx");
591   }
592   if (SanArgs.needsStatsRt()) {
593     NonWholeStaticRuntimes.push_back("stats");
594     RequiredSymbols.push_back("__sanitizer_stats_register");
595   }
596   if (SanArgs.needsEsanRt())
597     StaticRuntimes.push_back("esan");
598 }
599 
600 static void addLibFuzzerRuntime(const ToolChain &TC,
601                                 const ArgList &Args,
602                                 ArgStringList &CmdArgs) {
603   StringRef ParentDir =
604       llvm::sys::path::parent_path(TC.getDriver().InstalledDir);
605   SmallString<128> P(ParentDir);
606   llvm::sys::path::append(P, "lib", "libLLVMFuzzer.a");
607   CmdArgs.push_back(Args.MakeArgString(P));
608   if (!Args.hasArg(clang::driver::options::OPT_nostdlibxx))
609     TC.AddCXXStdlibLibArgs(Args, CmdArgs);
610 }
611 
612 
613 // Should be called before we add system libraries (C++ ABI, libstdc++/libc++,
614 // C runtime, etc). Returns true if sanitizer system deps need to be linked in.
615 bool tools::addSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
616                                  ArgStringList &CmdArgs) {
617   SmallVector<StringRef, 4> SharedRuntimes, StaticRuntimes,
618       NonWholeStaticRuntimes, HelperStaticRuntimes, RequiredSymbols;
619   collectSanitizerRuntimes(TC, Args, SharedRuntimes, StaticRuntimes,
620                            NonWholeStaticRuntimes, HelperStaticRuntimes,
621                            RequiredSymbols);
622   // Inject libfuzzer dependencies.
623   if (TC.getSanitizerArgs().needsFuzzer()
624       && !Args.hasArg(options::OPT_shared)) {
625     addLibFuzzerRuntime(TC, Args, CmdArgs);
626   }
627 
628   for (auto RT : SharedRuntimes)
629     addSanitizerRuntime(TC, Args, CmdArgs, RT, true, false);
630   for (auto RT : HelperStaticRuntimes)
631     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
632   bool AddExportDynamic = false;
633   for (auto RT : StaticRuntimes) {
634     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
635     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
636   }
637   for (auto RT : NonWholeStaticRuntimes) {
638     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, false);
639     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
640   }
641   for (auto S : RequiredSymbols) {
642     CmdArgs.push_back("-u");
643     CmdArgs.push_back(Args.MakeArgString(S));
644   }
645   // If there is a static runtime with no dynamic list, force all the symbols
646   // to be dynamic to be sure we export sanitizer interface functions.
647   if (AddExportDynamic)
648     CmdArgs.push_back("-export-dynamic");
649 
650   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
651   if (SanArgs.hasCrossDsoCfi() && !AddExportDynamic)
652     CmdArgs.push_back("-export-dynamic-symbol=__cfi_check");
653 
654   return !StaticRuntimes.empty() || !NonWholeStaticRuntimes.empty();
655 }
656 
657 bool tools::areOptimizationsEnabled(const ArgList &Args) {
658   // Find the last -O arg and see if it is non-zero.
659   if (Arg *A = Args.getLastArg(options::OPT_O_Group))
660     return !A->getOption().matches(options::OPT_O0);
661   // Defaults to -O0.
662   return false;
663 }
664 
665 const char *tools::SplitDebugName(const ArgList &Args, const InputInfo &Input) {
666   Arg *FinalOutput = Args.getLastArg(options::OPT_o);
667   if (FinalOutput && Args.hasArg(options::OPT_c)) {
668     SmallString<128> T(FinalOutput->getValue());
669     llvm::sys::path::replace_extension(T, "dwo");
670     return Args.MakeArgString(T);
671   } else {
672     // Use the compilation dir.
673     SmallString<128> T(
674         Args.getLastArgValue(options::OPT_fdebug_compilation_dir));
675     SmallString<128> F(llvm::sys::path::stem(Input.getBaseInput()));
676     llvm::sys::path::replace_extension(F, "dwo");
677     T += F;
678     return Args.MakeArgString(F);
679   }
680 }
681 
682 void tools::SplitDebugInfo(const ToolChain &TC, Compilation &C, const Tool &T,
683                            const JobAction &JA, const ArgList &Args,
684                            const InputInfo &Output, const char *OutFile) {
685   ArgStringList ExtractArgs;
686   ExtractArgs.push_back("--extract-dwo");
687 
688   ArgStringList StripArgs;
689   StripArgs.push_back("--strip-dwo");
690 
691   // Grabbing the output of the earlier compile step.
692   StripArgs.push_back(Output.getFilename());
693   ExtractArgs.push_back(Output.getFilename());
694   ExtractArgs.push_back(OutFile);
695 
696   const char *Exec = Args.MakeArgString(TC.GetProgramPath("objcopy"));
697   InputInfo II(types::TY_Object, Output.getFilename(), Output.getFilename());
698 
699   // First extract the dwo sections.
700   C.addCommand(llvm::make_unique<Command>(JA, T, Exec, ExtractArgs, II));
701 
702   // Then remove them from the original .o file.
703   C.addCommand(llvm::make_unique<Command>(JA, T, Exec, StripArgs, II));
704 }
705 
706 // Claim options we don't want to warn if they are unused. We do this for
707 // options that build systems might add but are unused when assembling or only
708 // running the preprocessor for example.
709 void tools::claimNoWarnArgs(const ArgList &Args) {
710   // Don't warn about unused -f(no-)?lto.  This can happen when we're
711   // preprocessing, precompiling or assembling.
712   Args.ClaimAllArgs(options::OPT_flto_EQ);
713   Args.ClaimAllArgs(options::OPT_flto);
714   Args.ClaimAllArgs(options::OPT_fno_lto);
715 }
716 
717 Arg *tools::getLastProfileUseArg(const ArgList &Args) {
718   auto *ProfileUseArg = Args.getLastArg(
719       options::OPT_fprofile_instr_use, options::OPT_fprofile_instr_use_EQ,
720       options::OPT_fprofile_use, options::OPT_fprofile_use_EQ,
721       options::OPT_fno_profile_instr_use);
722 
723   if (ProfileUseArg &&
724       ProfileUseArg->getOption().matches(options::OPT_fno_profile_instr_use))
725     ProfileUseArg = nullptr;
726 
727   return ProfileUseArg;
728 }
729 
730 Arg *tools::getLastProfileSampleUseArg(const ArgList &Args) {
731   auto *ProfileSampleUseArg = Args.getLastArg(
732       options::OPT_fprofile_sample_use, options::OPT_fprofile_sample_use_EQ,
733       options::OPT_fauto_profile, options::OPT_fauto_profile_EQ,
734       options::OPT_fno_profile_sample_use, options::OPT_fno_auto_profile);
735 
736   if (ProfileSampleUseArg &&
737       (ProfileSampleUseArg->getOption().matches(
738            options::OPT_fno_profile_sample_use) ||
739        ProfileSampleUseArg->getOption().matches(options::OPT_fno_auto_profile)))
740     return nullptr;
741 
742   return Args.getLastArg(options::OPT_fprofile_sample_use_EQ,
743                          options::OPT_fauto_profile_EQ);
744 }
745 
746 /// Parses the various -fpic/-fPIC/-fpie/-fPIE arguments.  Then,
747 /// smooshes them together with platform defaults, to decide whether
748 /// this compile should be using PIC mode or not. Returns a tuple of
749 /// (RelocationModel, PICLevel, IsPIE).
750 std::tuple<llvm::Reloc::Model, unsigned, bool>
751 tools::ParsePICArgs(const ToolChain &ToolChain, const ArgList &Args) {
752   const llvm::Triple &EffectiveTriple = ToolChain.getEffectiveTriple();
753   const llvm::Triple &Triple = ToolChain.getTriple();
754 
755   bool PIE = ToolChain.isPIEDefault();
756   bool PIC = PIE || ToolChain.isPICDefault();
757   // The Darwin/MachO default to use PIC does not apply when using -static.
758   if (Triple.isOSBinFormatMachO() && Args.hasArg(options::OPT_static))
759     PIE = PIC = false;
760   bool IsPICLevelTwo = PIC;
761 
762   bool KernelOrKext =
763       Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
764 
765   // Android-specific defaults for PIC/PIE
766   if (Triple.isAndroid()) {
767     switch (Triple.getArch()) {
768     case llvm::Triple::arm:
769     case llvm::Triple::armeb:
770     case llvm::Triple::thumb:
771     case llvm::Triple::thumbeb:
772     case llvm::Triple::aarch64:
773     case llvm::Triple::mips:
774     case llvm::Triple::mipsel:
775     case llvm::Triple::mips64:
776     case llvm::Triple::mips64el:
777       PIC = true; // "-fpic"
778       break;
779 
780     case llvm::Triple::x86:
781     case llvm::Triple::x86_64:
782       PIC = true; // "-fPIC"
783       IsPICLevelTwo = true;
784       break;
785 
786     default:
787       break;
788     }
789   }
790 
791   // OpenBSD-specific defaults for PIE
792   if (Triple.getOS() == llvm::Triple::OpenBSD) {
793     switch (ToolChain.getArch()) {
794     case llvm::Triple::arm:
795     case llvm::Triple::aarch64:
796     case llvm::Triple::mips64:
797     case llvm::Triple::mips64el:
798     case llvm::Triple::x86:
799     case llvm::Triple::x86_64:
800       IsPICLevelTwo = false; // "-fpie"
801       break;
802 
803     case llvm::Triple::ppc:
804     case llvm::Triple::sparc:
805     case llvm::Triple::sparcel:
806     case llvm::Triple::sparcv9:
807       IsPICLevelTwo = true; // "-fPIE"
808       break;
809 
810     default:
811       break;
812     }
813   }
814 
815   // The last argument relating to either PIC or PIE wins, and no
816   // other argument is used. If the last argument is any flavor of the
817   // '-fno-...' arguments, both PIC and PIE are disabled. Any PIE
818   // option implicitly enables PIC at the same level.
819   Arg *LastPICArg = Args.getLastArg(options::OPT_fPIC, options::OPT_fno_PIC,
820                                     options::OPT_fpic, options::OPT_fno_pic,
821                                     options::OPT_fPIE, options::OPT_fno_PIE,
822                                     options::OPT_fpie, options::OPT_fno_pie);
823   if (Triple.isOSWindows() && LastPICArg &&
824       LastPICArg ==
825           Args.getLastArg(options::OPT_fPIC, options::OPT_fpic,
826                           options::OPT_fPIE, options::OPT_fpie)) {
827     ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
828         << LastPICArg->getSpelling() << Triple.str();
829     if (Triple.getArch() == llvm::Triple::x86_64)
830       return std::make_tuple(llvm::Reloc::PIC_, 2U, false);
831     return std::make_tuple(llvm::Reloc::Static, 0U, false);
832   }
833 
834   // Check whether the tool chain trumps the PIC-ness decision. If the PIC-ness
835   // is forced, then neither PIC nor PIE flags will have no effect.
836   if (!ToolChain.isPICDefaultForced()) {
837     if (LastPICArg) {
838       Option O = LastPICArg->getOption();
839       if (O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic) ||
840           O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie)) {
841         PIE = O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie);
842         PIC =
843             PIE || O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic);
844         IsPICLevelTwo =
845             O.matches(options::OPT_fPIE) || O.matches(options::OPT_fPIC);
846       } else {
847         PIE = PIC = false;
848         if (EffectiveTriple.isPS4CPU()) {
849           Arg *ModelArg = Args.getLastArg(options::OPT_mcmodel_EQ);
850           StringRef Model = ModelArg ? ModelArg->getValue() : "";
851           if (Model != "kernel") {
852             PIC = true;
853             ToolChain.getDriver().Diag(diag::warn_drv_ps4_force_pic)
854                 << LastPICArg->getSpelling();
855           }
856         }
857       }
858     }
859   }
860 
861   // Introduce a Darwin and PS4-specific hack. If the default is PIC, but the
862   // PIC level would've been set to level 1, force it back to level 2 PIC
863   // instead.
864   if (PIC && (Triple.isOSDarwin() || EffectiveTriple.isPS4CPU()))
865     IsPICLevelTwo |= ToolChain.isPICDefault();
866 
867   // This kernel flags are a trump-card: they will disable PIC/PIE
868   // generation, independent of the argument order.
869   if (KernelOrKext &&
870       ((!EffectiveTriple.isiOS() || EffectiveTriple.isOSVersionLT(6)) &&
871        !EffectiveTriple.isWatchOS()))
872     PIC = PIE = false;
873 
874   if (Arg *A = Args.getLastArg(options::OPT_mdynamic_no_pic)) {
875     // This is a very special mode. It trumps the other modes, almost no one
876     // uses it, and it isn't even valid on any OS but Darwin.
877     if (!Triple.isOSDarwin())
878       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
879           << A->getSpelling() << Triple.str();
880 
881     // FIXME: Warn when this flag trumps some other PIC or PIE flag.
882 
883     // Only a forced PIC mode can cause the actual compile to have PIC defines
884     // etc., no flags are sufficient. This behavior was selected to closely
885     // match that of llvm-gcc and Apple GCC before that.
886     PIC = ToolChain.isPICDefault() && ToolChain.isPICDefaultForced();
887 
888     return std::make_tuple(llvm::Reloc::DynamicNoPIC, PIC ? 2U : 0U, false);
889   }
890 
891   bool EmbeddedPISupported;
892   switch (Triple.getArch()) {
893     case llvm::Triple::arm:
894     case llvm::Triple::armeb:
895     case llvm::Triple::thumb:
896     case llvm::Triple::thumbeb:
897       EmbeddedPISupported = true;
898       break;
899     default:
900       EmbeddedPISupported = false;
901       break;
902   }
903 
904   bool ROPI = false, RWPI = false;
905   Arg* LastROPIArg = Args.getLastArg(options::OPT_fropi, options::OPT_fno_ropi);
906   if (LastROPIArg && LastROPIArg->getOption().matches(options::OPT_fropi)) {
907     if (!EmbeddedPISupported)
908       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
909           << LastROPIArg->getSpelling() << Triple.str();
910     ROPI = true;
911   }
912   Arg *LastRWPIArg = Args.getLastArg(options::OPT_frwpi, options::OPT_fno_rwpi);
913   if (LastRWPIArg && LastRWPIArg->getOption().matches(options::OPT_frwpi)) {
914     if (!EmbeddedPISupported)
915       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
916           << LastRWPIArg->getSpelling() << Triple.str();
917     RWPI = true;
918   }
919 
920   // ROPI and RWPI are not comaptible with PIC or PIE.
921   if ((ROPI || RWPI) && (PIC || PIE))
922     ToolChain.getDriver().Diag(diag::err_drv_ropi_rwpi_incompatible_with_pic);
923 
924   // When targettng MIPS64 with N64, the default is PIC, unless -mno-abicalls is
925   // used.
926   if ((Triple.getArch() == llvm::Triple::mips64 ||
927        Triple.getArch() == llvm::Triple::mips64el) &&
928       Args.hasArg(options::OPT_mno_abicalls))
929     return std::make_tuple(llvm::Reloc::Static, 0U, false);
930 
931   if (PIC)
932     return std::make_tuple(llvm::Reloc::PIC_, IsPICLevelTwo ? 2U : 1U, PIE);
933 
934   llvm::Reloc::Model RelocM = llvm::Reloc::Static;
935   if (ROPI && RWPI)
936     RelocM = llvm::Reloc::ROPI_RWPI;
937   else if (ROPI)
938     RelocM = llvm::Reloc::ROPI;
939   else if (RWPI)
940     RelocM = llvm::Reloc::RWPI;
941 
942   return std::make_tuple(RelocM, 0U, false);
943 }
944 
945 void tools::AddAssemblerKPIC(const ToolChain &ToolChain, const ArgList &Args,
946                              ArgStringList &CmdArgs) {
947   llvm::Reloc::Model RelocationModel;
948   unsigned PICLevel;
949   bool IsPIE;
950   std::tie(RelocationModel, PICLevel, IsPIE) = ParsePICArgs(ToolChain, Args);
951 
952   if (RelocationModel != llvm::Reloc::Static)
953     CmdArgs.push_back("-KPIC");
954 }
955 
956 /// \brief Determine whether Objective-C automated reference counting is
957 /// enabled.
958 bool tools::isObjCAutoRefCount(const ArgList &Args) {
959   return Args.hasFlag(options::OPT_fobjc_arc, options::OPT_fno_objc_arc, false);
960 }
961 
962 static void AddLibgcc(const llvm::Triple &Triple, const Driver &D,
963                       ArgStringList &CmdArgs, const ArgList &Args) {
964   bool isAndroid = Triple.isAndroid();
965   bool isCygMing = Triple.isOSCygMing();
966   bool IsIAMCU = Triple.isOSIAMCU();
967   bool StaticLibgcc = Args.hasArg(options::OPT_static_libgcc) ||
968                       Args.hasArg(options::OPT_static);
969   if (!D.CCCIsCXX())
970     CmdArgs.push_back("-lgcc");
971 
972   if (StaticLibgcc || isAndroid) {
973     if (D.CCCIsCXX())
974       CmdArgs.push_back("-lgcc");
975   } else {
976     if (!D.CCCIsCXX() && !isCygMing)
977       CmdArgs.push_back("--as-needed");
978     CmdArgs.push_back("-lgcc_s");
979     if (!D.CCCIsCXX() && !isCygMing)
980       CmdArgs.push_back("--no-as-needed");
981   }
982 
983   if (StaticLibgcc && !isAndroid && !IsIAMCU)
984     CmdArgs.push_back("-lgcc_eh");
985   else if (!Args.hasArg(options::OPT_shared) && D.CCCIsCXX())
986     CmdArgs.push_back("-lgcc");
987 
988   // According to Android ABI, we have to link with libdl if we are
989   // linking with non-static libgcc.
990   //
991   // NOTE: This fixes a link error on Android MIPS as well.  The non-static
992   // libgcc for MIPS relies on _Unwind_Find_FDE and dl_iterate_phdr from libdl.
993   if (isAndroid && !StaticLibgcc)
994     CmdArgs.push_back("-ldl");
995 }
996 
997 void tools::AddRunTimeLibs(const ToolChain &TC, const Driver &D,
998                            ArgStringList &CmdArgs, const ArgList &Args) {
999   // Make use of compiler-rt if --rtlib option is used
1000   ToolChain::RuntimeLibType RLT = TC.GetRuntimeLibType(Args);
1001 
1002   switch (RLT) {
1003   case ToolChain::RLT_CompilerRT:
1004     switch (TC.getTriple().getOS()) {
1005     default:
1006       llvm_unreachable("unsupported OS");
1007     case llvm::Triple::Win32:
1008     case llvm::Triple::Linux:
1009     case llvm::Triple::Fuchsia:
1010       CmdArgs.push_back(TC.getCompilerRTArgString(Args, "builtins"));
1011       break;
1012     }
1013     break;
1014   case ToolChain::RLT_Libgcc:
1015     // Make sure libgcc is not used under MSVC environment by default
1016     if (TC.getTriple().isKnownWindowsMSVCEnvironment()) {
1017       // Issue error diagnostic if libgcc is explicitly specified
1018       // through command line as --rtlib option argument.
1019       if (Args.hasArg(options::OPT_rtlib_EQ)) {
1020         TC.getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
1021             << Args.getLastArg(options::OPT_rtlib_EQ)->getValue() << "MSVC";
1022       }
1023     } else
1024       AddLibgcc(TC.getTriple(), D, CmdArgs, Args);
1025     break;
1026   }
1027 }
1028 
1029 /// Add OpenMP linker script arguments at the end of the argument list so that
1030 /// the fat binary is built by embedding each of the device images into the
1031 /// host. The linker script also defines a few symbols required by the code
1032 /// generation so that the images can be easily retrieved at runtime by the
1033 /// offloading library. This should be used only in tool chains that support
1034 /// linker scripts.
1035 void tools::AddOpenMPLinkerScript(const ToolChain &TC, Compilation &C,
1036                                   const InputInfo &Output,
1037                                   const InputInfoList &Inputs,
1038                                   const ArgList &Args, ArgStringList &CmdArgs,
1039                                   const JobAction &JA) {
1040 
1041   // If this is not an OpenMP host toolchain, we don't need to do anything.
1042   if (!JA.isHostOffloading(Action::OFK_OpenMP))
1043     return;
1044 
1045   // Create temporary linker script. Keep it if save-temps is enabled.
1046   const char *LKS;
1047   SmallString<256> Name = llvm::sys::path::filename(Output.getFilename());
1048   if (C.getDriver().isSaveTempsEnabled()) {
1049     llvm::sys::path::replace_extension(Name, "lk");
1050     LKS = C.getArgs().MakeArgString(Name.c_str());
1051   } else {
1052     llvm::sys::path::replace_extension(Name, "");
1053     Name = C.getDriver().GetTemporaryPath(Name, "lk");
1054     LKS = C.addTempFile(C.getArgs().MakeArgString(Name.c_str()));
1055   }
1056 
1057   // Add linker script option to the command.
1058   CmdArgs.push_back("-T");
1059   CmdArgs.push_back(LKS);
1060 
1061   // Create a buffer to write the contents of the linker script.
1062   std::string LksBuffer;
1063   llvm::raw_string_ostream LksStream(LksBuffer);
1064 
1065   // Get the OpenMP offload tool chains so that we can extract the triple
1066   // associated with each device input.
1067   auto OpenMPToolChains = C.getOffloadToolChains<Action::OFK_OpenMP>();
1068   assert(OpenMPToolChains.first != OpenMPToolChains.second &&
1069          "No OpenMP toolchains??");
1070 
1071   // Track the input file name and device triple in order to build the script,
1072   // inserting binaries in the designated sections.
1073   SmallVector<std::pair<std::string, const char *>, 8> InputBinaryInfo;
1074 
1075   // Add commands to embed target binaries. We ensure that each section and
1076   // image is 16-byte aligned. This is not mandatory, but increases the
1077   // likelihood of data to be aligned with a cache block in several main host
1078   // machines.
1079   LksStream << "/*\n";
1080   LksStream << "       OpenMP Offload Linker Script\n";
1081   LksStream << " *** Automatically generated by Clang ***\n";
1082   LksStream << "*/\n";
1083   LksStream << "TARGET(binary)\n";
1084   auto DTC = OpenMPToolChains.first;
1085   for (auto &II : Inputs) {
1086     const Action *A = II.getAction();
1087     // Is this a device linking action?
1088     if (A && isa<LinkJobAction>(A) &&
1089         A->isDeviceOffloading(Action::OFK_OpenMP)) {
1090       assert(DTC != OpenMPToolChains.second &&
1091              "More device inputs than device toolchains??");
1092       InputBinaryInfo.push_back(std::make_pair(
1093           DTC->second->getTriple().normalize(), II.getFilename()));
1094       ++DTC;
1095       LksStream << "INPUT(" << II.getFilename() << ")\n";
1096     }
1097   }
1098 
1099   assert(DTC == OpenMPToolChains.second &&
1100          "Less device inputs than device toolchains??");
1101 
1102   LksStream << "SECTIONS\n";
1103   LksStream << "{\n";
1104 
1105   // Put each target binary into a separate section.
1106   for (const auto &BI : InputBinaryInfo) {
1107     LksStream << "  .omp_offloading." << BI.first << " :\n";
1108     LksStream << "  ALIGN(0x10)\n";
1109     LksStream << "  {\n";
1110     LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_start." << BI.first
1111               << " = .);\n";
1112     LksStream << "    " << BI.second << "\n";
1113     LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_end." << BI.first
1114               << " = .);\n";
1115     LksStream << "  }\n";
1116   }
1117 
1118   // Add commands to define host entries begin and end. We use 1-byte subalign
1119   // so that the linker does not add any padding and the elements in this
1120   // section form an array.
1121   LksStream << "  .omp_offloading.entries :\n";
1122   LksStream << "  ALIGN(0x10)\n";
1123   LksStream << "  SUBALIGN(0x01)\n";
1124   LksStream << "  {\n";
1125   LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_begin = .);\n";
1126   LksStream << "    *(.omp_offloading.entries)\n";
1127   LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_end = .);\n";
1128   LksStream << "  }\n";
1129   LksStream << "}\n";
1130   LksStream << "INSERT BEFORE .data\n";
1131   LksStream.flush();
1132 
1133   // Dump the contents of the linker script if the user requested that. We
1134   // support this option to enable testing of behavior with -###.
1135   if (C.getArgs().hasArg(options::OPT_fopenmp_dump_offload_linker_script))
1136     llvm::errs() << LksBuffer;
1137 
1138   // If this is a dry run, do not create the linker script file.
1139   if (C.getArgs().hasArg(options::OPT__HASH_HASH_HASH))
1140     return;
1141 
1142   // Open script file and write the contents.
1143   std::error_code EC;
1144   llvm::raw_fd_ostream Lksf(LKS, EC, llvm::sys::fs::F_None);
1145 
1146   if (EC) {
1147     C.getDriver().Diag(clang::diag::err_unable_to_make_temp) << EC.message();
1148     return;
1149   }
1150 
1151   Lksf << LksBuffer;
1152 }
1153