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::bpfel:
324   case llvm::Triple::bpfeb:
325   case llvm::Triple::sparc:
326   case llvm::Triple::sparcel:
327   case llvm::Triple::sparcv9:
328     if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
329       return A->getValue();
330     return "";
331 
332   case llvm::Triple::x86:
333   case llvm::Triple::x86_64:
334     return x86::getX86TargetCPU(Args, T);
335 
336   case llvm::Triple::hexagon:
337     return "hexagon" +
338            toolchains::HexagonToolChain::GetTargetCPUVersion(Args).str();
339 
340   case llvm::Triple::lanai:
341     return getLanaiTargetCPU(Args);
342 
343   case llvm::Triple::systemz:
344     return systemz::getSystemZTargetCPU(Args);
345 
346   case llvm::Triple::r600:
347   case llvm::Triple::amdgcn:
348     return getR600TargetGPU(Args);
349 
350   case llvm::Triple::wasm32:
351   case llvm::Triple::wasm64:
352     return getWebAssemblyTargetCPU(Args);
353   }
354 }
355 
356 unsigned tools::getLTOParallelism(const ArgList &Args, const Driver &D) {
357   unsigned Parallelism = 0;
358   Arg *LtoJobsArg = Args.getLastArg(options::OPT_flto_jobs_EQ);
359   if (LtoJobsArg &&
360       StringRef(LtoJobsArg->getValue()).getAsInteger(10, Parallelism))
361     D.Diag(diag::err_drv_invalid_int_value) << LtoJobsArg->getAsString(Args)
362                                             << LtoJobsArg->getValue();
363   return Parallelism;
364 }
365 
366 // CloudABI and WebAssembly use -ffunction-sections and -fdata-sections by
367 // default.
368 bool tools::isUseSeparateSections(const llvm::Triple &Triple) {
369   return Triple.getOS() == llvm::Triple::CloudABI ||
370          Triple.getArch() == llvm::Triple::wasm32 ||
371          Triple.getArch() == llvm::Triple::wasm64;
372 }
373 
374 void tools::AddGoldPlugin(const ToolChain &ToolChain, const ArgList &Args,
375                           ArgStringList &CmdArgs, bool IsThinLTO,
376                           const Driver &D) {
377   // Tell the linker to load the plugin. This has to come before AddLinkerInputs
378   // as gold requires -plugin to come before any -plugin-opt that -Wl might
379   // forward.
380   CmdArgs.push_back("-plugin");
381 
382 #if defined(LLVM_ON_WIN32)
383   const char *Suffix = ".dll";
384 #elif defined(__APPLE__)
385   const char *Suffix = ".dylib";
386 #else
387   const char *Suffix = ".so";
388 #endif
389 
390   SmallString<1024> Plugin;
391   llvm::sys::path::native(Twine(ToolChain.getDriver().Dir) +
392                               "/../lib" CLANG_LIBDIR_SUFFIX "/LLVMgold" +
393                               Suffix,
394                           Plugin);
395   CmdArgs.push_back(Args.MakeArgString(Plugin));
396 
397   // Try to pass driver level flags relevant to LTO code generation down to
398   // the plugin.
399 
400   // Handle flags for selecting CPU variants.
401   std::string CPU = getCPUName(Args, ToolChain.getTriple());
402   if (!CPU.empty())
403     CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=mcpu=") + CPU));
404 
405   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
406     StringRef OOpt;
407     if (A->getOption().matches(options::OPT_O4) ||
408         A->getOption().matches(options::OPT_Ofast))
409       OOpt = "3";
410     else if (A->getOption().matches(options::OPT_O))
411       OOpt = A->getValue();
412     else if (A->getOption().matches(options::OPT_O0))
413       OOpt = "0";
414     if (!OOpt.empty())
415       CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=O") + OOpt));
416   }
417 
418   if (IsThinLTO)
419     CmdArgs.push_back("-plugin-opt=thinlto");
420 
421   if (unsigned Parallelism = getLTOParallelism(Args, D))
422     CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=jobs=") +
423                                          llvm::to_string(Parallelism)));
424 
425   // If an explicit debugger tuning argument appeared, pass it along.
426   if (Arg *A = Args.getLastArg(options::OPT_gTune_Group,
427                                options::OPT_ggdbN_Group)) {
428     if (A->getOption().matches(options::OPT_glldb))
429       CmdArgs.push_back("-plugin-opt=-debugger-tune=lldb");
430     else if (A->getOption().matches(options::OPT_gsce))
431       CmdArgs.push_back("-plugin-opt=-debugger-tune=sce");
432     else
433       CmdArgs.push_back("-plugin-opt=-debugger-tune=gdb");
434   }
435 
436   bool UseSeparateSections =
437       isUseSeparateSections(ToolChain.getEffectiveTriple());
438 
439   if (Args.hasFlag(options::OPT_ffunction_sections,
440                    options::OPT_fno_function_sections, UseSeparateSections)) {
441     CmdArgs.push_back("-plugin-opt=-function-sections");
442   }
443 
444   if (Args.hasFlag(options::OPT_fdata_sections, options::OPT_fno_data_sections,
445                    UseSeparateSections)) {
446     CmdArgs.push_back("-plugin-opt=-data-sections");
447   }
448 
449   if (Arg *A = getLastProfileSampleUseArg(Args)) {
450     StringRef FName = A->getValue();
451     if (!llvm::sys::fs::exists(FName))
452       D.Diag(diag::err_drv_no_such_file) << FName;
453     else
454       CmdArgs.push_back(
455           Args.MakeArgString(Twine("-plugin-opt=sample-profile=") + FName));
456   }
457 }
458 
459 void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
460                                  ArgStringList &CmdArgs) {
461   std::string CandidateRPath = TC.getArchSpecificLibPath();
462   if (TC.getVFS().exists(CandidateRPath)) {
463     CmdArgs.push_back("-rpath");
464     CmdArgs.push_back(Args.MakeArgString(CandidateRPath.c_str()));
465   }
466 }
467 
468 bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
469                              const ArgList &Args, bool IsOffloadingHost,
470                              bool GompNeedsRT) {
471   if (!Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
472                     options::OPT_fno_openmp, false))
473     return false;
474 
475   switch (TC.getDriver().getOpenMPRuntime(Args)) {
476   case Driver::OMPRT_OMP:
477     CmdArgs.push_back("-lomp");
478     break;
479   case Driver::OMPRT_GOMP:
480     CmdArgs.push_back("-lgomp");
481 
482     if (GompNeedsRT)
483       CmdArgs.push_back("-lrt");
484     break;
485   case Driver::OMPRT_IOMP5:
486     CmdArgs.push_back("-liomp5");
487     break;
488   case Driver::OMPRT_Unknown:
489     // Already diagnosed.
490     return false;
491   }
492 
493   if (IsOffloadingHost)
494     CmdArgs.push_back("-lomptarget");
495 
496   addArchSpecificRPath(TC, Args, CmdArgs);
497 
498   return true;
499 }
500 
501 static void addSanitizerRuntime(const ToolChain &TC, const ArgList &Args,
502                                 ArgStringList &CmdArgs, StringRef Sanitizer,
503                                 bool IsShared, bool IsWhole) {
504   // Wrap any static runtimes that must be forced into executable in
505   // whole-archive.
506   if (IsWhole) CmdArgs.push_back("-whole-archive");
507   CmdArgs.push_back(TC.getCompilerRTArgString(Args, Sanitizer, IsShared));
508   if (IsWhole) CmdArgs.push_back("-no-whole-archive");
509 
510   if (IsShared) {
511     addArchSpecificRPath(TC, Args, CmdArgs);
512   }
513 }
514 
515 // Tries to use a file with the list of dynamic symbols that need to be exported
516 // from the runtime library. Returns true if the file was found.
517 static bool addSanitizerDynamicList(const ToolChain &TC, const ArgList &Args,
518                                     ArgStringList &CmdArgs,
519                                     StringRef Sanitizer) {
520   SmallString<128> SanRT(TC.getCompilerRT(Args, Sanitizer));
521   if (llvm::sys::fs::exists(SanRT + ".syms")) {
522     CmdArgs.push_back(Args.MakeArgString("--dynamic-list=" + SanRT + ".syms"));
523     return true;
524   }
525   return false;
526 }
527 
528 void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,
529                                      ArgStringList &CmdArgs) {
530   // Force linking against the system libraries sanitizers depends on
531   // (see PR15823 why this is necessary).
532   CmdArgs.push_back("--no-as-needed");
533   // There's no libpthread or librt on RTEMS.
534   if (TC.getTriple().getOS() != llvm::Triple::RTEMS) {
535     CmdArgs.push_back("-lpthread");
536     CmdArgs.push_back("-lrt");
537   }
538   CmdArgs.push_back("-lm");
539   // There's no libdl on FreeBSD or RTEMS.
540   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
541       TC.getTriple().getOS() != llvm::Triple::NetBSD &&
542       TC.getTriple().getOS() != llvm::Triple::RTEMS)
543     CmdArgs.push_back("-ldl");
544 }
545 
546 static void
547 collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
548                          SmallVectorImpl<StringRef> &SharedRuntimes,
549                          SmallVectorImpl<StringRef> &StaticRuntimes,
550                          SmallVectorImpl<StringRef> &NonWholeStaticRuntimes,
551                          SmallVectorImpl<StringRef> &HelperStaticRuntimes,
552                          SmallVectorImpl<StringRef> &RequiredSymbols) {
553   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
554   // Collect shared runtimes.
555   if (SanArgs.needsAsanRt() && SanArgs.needsSharedAsanRt()) {
556     SharedRuntimes.push_back("asan");
557   }
558 
559   // The stats_client library is also statically linked into DSOs.
560   if (SanArgs.needsStatsRt())
561     StaticRuntimes.push_back("stats_client");
562 
563   // Collect static runtimes.
564   if (Args.hasArg(options::OPT_shared) || TC.getTriple().isAndroid()) {
565     // Don't link static runtimes into DSOs or if compiling for Android.
566     return;
567   }
568   if (SanArgs.needsAsanRt()) {
569     if (SanArgs.needsSharedAsanRt()) {
570       HelperStaticRuntimes.push_back("asan-preinit");
571     } else {
572       StaticRuntimes.push_back("asan");
573       if (SanArgs.linkCXXRuntimes())
574         StaticRuntimes.push_back("asan_cxx");
575     }
576   }
577   if (SanArgs.needsDfsanRt())
578     StaticRuntimes.push_back("dfsan");
579   if (SanArgs.needsLsanRt())
580     StaticRuntimes.push_back("lsan");
581   if (SanArgs.needsMsanRt()) {
582     StaticRuntimes.push_back("msan");
583     if (SanArgs.linkCXXRuntimes())
584       StaticRuntimes.push_back("msan_cxx");
585   }
586   if (SanArgs.needsTsanRt()) {
587     StaticRuntimes.push_back("tsan");
588     if (SanArgs.linkCXXRuntimes())
589       StaticRuntimes.push_back("tsan_cxx");
590   }
591   if (SanArgs.needsUbsanRt()) {
592     if (SanArgs.requiresMinimalRuntime()) {
593       StaticRuntimes.push_back("ubsan_minimal");
594     } else {
595       StaticRuntimes.push_back("ubsan_standalone");
596       if (SanArgs.linkCXXRuntimes())
597         StaticRuntimes.push_back("ubsan_standalone_cxx");
598     }
599   }
600   if (SanArgs.needsSafeStackRt()) {
601     NonWholeStaticRuntimes.push_back("safestack");
602     RequiredSymbols.push_back("__safestack_init");
603   }
604   if (SanArgs.needsCfiRt())
605     StaticRuntimes.push_back("cfi");
606   if (SanArgs.needsCfiDiagRt()) {
607     StaticRuntimes.push_back("cfi_diag");
608     if (SanArgs.linkCXXRuntimes())
609       StaticRuntimes.push_back("ubsan_standalone_cxx");
610   }
611   if (SanArgs.needsStatsRt()) {
612     NonWholeStaticRuntimes.push_back("stats");
613     RequiredSymbols.push_back("__sanitizer_stats_register");
614   }
615   if (SanArgs.needsEsanRt())
616     StaticRuntimes.push_back("esan");
617 }
618 
619 // Should be called before we add system libraries (C++ ABI, libstdc++/libc++,
620 // C runtime, etc). Returns true if sanitizer system deps need to be linked in.
621 bool tools::addSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
622                                  ArgStringList &CmdArgs) {
623   SmallVector<StringRef, 4> SharedRuntimes, StaticRuntimes,
624       NonWholeStaticRuntimes, HelperStaticRuntimes, RequiredSymbols;
625   collectSanitizerRuntimes(TC, Args, SharedRuntimes, StaticRuntimes,
626                            NonWholeStaticRuntimes, HelperStaticRuntimes,
627                            RequiredSymbols);
628 
629   // Inject libfuzzer dependencies.
630   if (TC.getSanitizerArgs().needsFuzzer()
631       && !Args.hasArg(options::OPT_shared)) {
632 
633     addSanitizerRuntime(TC, Args, CmdArgs, "fuzzer", false, true);
634     if (!Args.hasArg(clang::driver::options::OPT_nostdlibxx))
635       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
636   }
637 
638   for (auto RT : SharedRuntimes)
639     addSanitizerRuntime(TC, Args, CmdArgs, RT, true, false);
640   for (auto RT : HelperStaticRuntimes)
641     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
642   bool AddExportDynamic = false;
643   for (auto RT : StaticRuntimes) {
644     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
645     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
646   }
647   for (auto RT : NonWholeStaticRuntimes) {
648     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, false);
649     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
650   }
651   for (auto S : RequiredSymbols) {
652     CmdArgs.push_back("-u");
653     CmdArgs.push_back(Args.MakeArgString(S));
654   }
655   // If there is a static runtime with no dynamic list, force all the symbols
656   // to be dynamic to be sure we export sanitizer interface functions.
657   if (AddExportDynamic)
658     CmdArgs.push_back("-export-dynamic");
659 
660   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
661   if (SanArgs.hasCrossDsoCfi() && !AddExportDynamic)
662     CmdArgs.push_back("-export-dynamic-symbol=__cfi_check");
663 
664   return !StaticRuntimes.empty() || !NonWholeStaticRuntimes.empty();
665 }
666 
667 bool tools::areOptimizationsEnabled(const ArgList &Args) {
668   // Find the last -O arg and see if it is non-zero.
669   if (Arg *A = Args.getLastArg(options::OPT_O_Group))
670     return !A->getOption().matches(options::OPT_O0);
671   // Defaults to -O0.
672   return false;
673 }
674 
675 const char *tools::SplitDebugName(const ArgList &Args, const InputInfo &Input) {
676   Arg *FinalOutput = Args.getLastArg(options::OPT_o);
677   if (FinalOutput && Args.hasArg(options::OPT_c)) {
678     SmallString<128> T(FinalOutput->getValue());
679     llvm::sys::path::replace_extension(T, "dwo");
680     return Args.MakeArgString(T);
681   } else {
682     // Use the compilation dir.
683     SmallString<128> T(
684         Args.getLastArgValue(options::OPT_fdebug_compilation_dir));
685     SmallString<128> F(llvm::sys::path::stem(Input.getBaseInput()));
686     llvm::sys::path::replace_extension(F, "dwo");
687     T += F;
688     return Args.MakeArgString(F);
689   }
690 }
691 
692 void tools::SplitDebugInfo(const ToolChain &TC, Compilation &C, const Tool &T,
693                            const JobAction &JA, const ArgList &Args,
694                            const InputInfo &Output, const char *OutFile) {
695   ArgStringList ExtractArgs;
696   ExtractArgs.push_back("--extract-dwo");
697 
698   ArgStringList StripArgs;
699   StripArgs.push_back("--strip-dwo");
700 
701   // Grabbing the output of the earlier compile step.
702   StripArgs.push_back(Output.getFilename());
703   ExtractArgs.push_back(Output.getFilename());
704   ExtractArgs.push_back(OutFile);
705 
706   const char *Exec = Args.MakeArgString(TC.GetProgramPath("objcopy"));
707   InputInfo II(types::TY_Object, Output.getFilename(), Output.getFilename());
708 
709   // First extract the dwo sections.
710   C.addCommand(llvm::make_unique<Command>(JA, T, Exec, ExtractArgs, II));
711 
712   // Then remove them from the original .o file.
713   C.addCommand(llvm::make_unique<Command>(JA, T, Exec, StripArgs, II));
714 }
715 
716 // Claim options we don't want to warn if they are unused. We do this for
717 // options that build systems might add but are unused when assembling or only
718 // running the preprocessor for example.
719 void tools::claimNoWarnArgs(const ArgList &Args) {
720   // Don't warn about unused -f(no-)?lto.  This can happen when we're
721   // preprocessing, precompiling or assembling.
722   Args.ClaimAllArgs(options::OPT_flto_EQ);
723   Args.ClaimAllArgs(options::OPT_flto);
724   Args.ClaimAllArgs(options::OPT_fno_lto);
725 }
726 
727 Arg *tools::getLastProfileUseArg(const ArgList &Args) {
728   auto *ProfileUseArg = Args.getLastArg(
729       options::OPT_fprofile_instr_use, options::OPT_fprofile_instr_use_EQ,
730       options::OPT_fprofile_use, options::OPT_fprofile_use_EQ,
731       options::OPT_fno_profile_instr_use);
732 
733   if (ProfileUseArg &&
734       ProfileUseArg->getOption().matches(options::OPT_fno_profile_instr_use))
735     ProfileUseArg = nullptr;
736 
737   return ProfileUseArg;
738 }
739 
740 Arg *tools::getLastProfileSampleUseArg(const ArgList &Args) {
741   auto *ProfileSampleUseArg = Args.getLastArg(
742       options::OPT_fprofile_sample_use, options::OPT_fprofile_sample_use_EQ,
743       options::OPT_fauto_profile, options::OPT_fauto_profile_EQ,
744       options::OPT_fno_profile_sample_use, options::OPT_fno_auto_profile);
745 
746   if (ProfileSampleUseArg &&
747       (ProfileSampleUseArg->getOption().matches(
748            options::OPT_fno_profile_sample_use) ||
749        ProfileSampleUseArg->getOption().matches(options::OPT_fno_auto_profile)))
750     return nullptr;
751 
752   return Args.getLastArg(options::OPT_fprofile_sample_use_EQ,
753                          options::OPT_fauto_profile_EQ);
754 }
755 
756 /// Parses the various -fpic/-fPIC/-fpie/-fPIE arguments.  Then,
757 /// smooshes them together with platform defaults, to decide whether
758 /// this compile should be using PIC mode or not. Returns a tuple of
759 /// (RelocationModel, PICLevel, IsPIE).
760 std::tuple<llvm::Reloc::Model, unsigned, bool>
761 tools::ParsePICArgs(const ToolChain &ToolChain, const ArgList &Args) {
762   const llvm::Triple &EffectiveTriple = ToolChain.getEffectiveTriple();
763   const llvm::Triple &Triple = ToolChain.getTriple();
764 
765   bool PIE = ToolChain.isPIEDefault();
766   bool PIC = PIE || ToolChain.isPICDefault();
767   // The Darwin/MachO default to use PIC does not apply when using -static.
768   if (Triple.isOSBinFormatMachO() && Args.hasArg(options::OPT_static))
769     PIE = PIC = false;
770   bool IsPICLevelTwo = PIC;
771 
772   bool KernelOrKext =
773       Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
774 
775   // Android-specific defaults for PIC/PIE
776   if (Triple.isAndroid()) {
777     switch (Triple.getArch()) {
778     case llvm::Triple::arm:
779     case llvm::Triple::armeb:
780     case llvm::Triple::thumb:
781     case llvm::Triple::thumbeb:
782     case llvm::Triple::aarch64:
783     case llvm::Triple::mips:
784     case llvm::Triple::mipsel:
785     case llvm::Triple::mips64:
786     case llvm::Triple::mips64el:
787       PIC = true; // "-fpic"
788       break;
789 
790     case llvm::Triple::x86:
791     case llvm::Triple::x86_64:
792       PIC = true; // "-fPIC"
793       IsPICLevelTwo = true;
794       break;
795 
796     default:
797       break;
798     }
799   }
800 
801   // OpenBSD-specific defaults for PIE
802   if (Triple.getOS() == llvm::Triple::OpenBSD) {
803     switch (ToolChain.getArch()) {
804     case llvm::Triple::arm:
805     case llvm::Triple::aarch64:
806     case llvm::Triple::mips64:
807     case llvm::Triple::mips64el:
808     case llvm::Triple::x86:
809     case llvm::Triple::x86_64:
810       IsPICLevelTwo = false; // "-fpie"
811       break;
812 
813     case llvm::Triple::ppc:
814     case llvm::Triple::sparc:
815     case llvm::Triple::sparcel:
816     case llvm::Triple::sparcv9:
817       IsPICLevelTwo = true; // "-fPIE"
818       break;
819 
820     default:
821       break;
822     }
823   }
824 
825   // The last argument relating to either PIC or PIE wins, and no
826   // other argument is used. If the last argument is any flavor of the
827   // '-fno-...' arguments, both PIC and PIE are disabled. Any PIE
828   // option implicitly enables PIC at the same level.
829   Arg *LastPICArg = Args.getLastArg(options::OPT_fPIC, options::OPT_fno_PIC,
830                                     options::OPT_fpic, options::OPT_fno_pic,
831                                     options::OPT_fPIE, options::OPT_fno_PIE,
832                                     options::OPT_fpie, options::OPT_fno_pie);
833   if (Triple.isOSWindows() && LastPICArg &&
834       LastPICArg ==
835           Args.getLastArg(options::OPT_fPIC, options::OPT_fpic,
836                           options::OPT_fPIE, options::OPT_fpie)) {
837     ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
838         << LastPICArg->getSpelling() << Triple.str();
839     if (Triple.getArch() == llvm::Triple::x86_64)
840       return std::make_tuple(llvm::Reloc::PIC_, 2U, false);
841     return std::make_tuple(llvm::Reloc::Static, 0U, false);
842   }
843 
844   // Check whether the tool chain trumps the PIC-ness decision. If the PIC-ness
845   // is forced, then neither PIC nor PIE flags will have no effect.
846   if (!ToolChain.isPICDefaultForced()) {
847     if (LastPICArg) {
848       Option O = LastPICArg->getOption();
849       if (O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic) ||
850           O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie)) {
851         PIE = O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie);
852         PIC =
853             PIE || O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic);
854         IsPICLevelTwo =
855             O.matches(options::OPT_fPIE) || O.matches(options::OPT_fPIC);
856       } else {
857         PIE = PIC = false;
858         if (EffectiveTriple.isPS4CPU()) {
859           Arg *ModelArg = Args.getLastArg(options::OPT_mcmodel_EQ);
860           StringRef Model = ModelArg ? ModelArg->getValue() : "";
861           if (Model != "kernel") {
862             PIC = true;
863             ToolChain.getDriver().Diag(diag::warn_drv_ps4_force_pic)
864                 << LastPICArg->getSpelling();
865           }
866         }
867       }
868     }
869   }
870 
871   // Introduce a Darwin and PS4-specific hack. If the default is PIC, but the
872   // PIC level would've been set to level 1, force it back to level 2 PIC
873   // instead.
874   if (PIC && (Triple.isOSDarwin() || EffectiveTriple.isPS4CPU()))
875     IsPICLevelTwo |= ToolChain.isPICDefault();
876 
877   // This kernel flags are a trump-card: they will disable PIC/PIE
878   // generation, independent of the argument order.
879   if (KernelOrKext &&
880       ((!EffectiveTriple.isiOS() || EffectiveTriple.isOSVersionLT(6)) &&
881        !EffectiveTriple.isWatchOS()))
882     PIC = PIE = false;
883 
884   if (Arg *A = Args.getLastArg(options::OPT_mdynamic_no_pic)) {
885     // This is a very special mode. It trumps the other modes, almost no one
886     // uses it, and it isn't even valid on any OS but Darwin.
887     if (!Triple.isOSDarwin())
888       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
889           << A->getSpelling() << Triple.str();
890 
891     // FIXME: Warn when this flag trumps some other PIC or PIE flag.
892 
893     // Only a forced PIC mode can cause the actual compile to have PIC defines
894     // etc., no flags are sufficient. This behavior was selected to closely
895     // match that of llvm-gcc and Apple GCC before that.
896     PIC = ToolChain.isPICDefault() && ToolChain.isPICDefaultForced();
897 
898     return std::make_tuple(llvm::Reloc::DynamicNoPIC, PIC ? 2U : 0U, false);
899   }
900 
901   bool EmbeddedPISupported;
902   switch (Triple.getArch()) {
903     case llvm::Triple::arm:
904     case llvm::Triple::armeb:
905     case llvm::Triple::thumb:
906     case llvm::Triple::thumbeb:
907       EmbeddedPISupported = true;
908       break;
909     default:
910       EmbeddedPISupported = false;
911       break;
912   }
913 
914   bool ROPI = false, RWPI = false;
915   Arg* LastROPIArg = Args.getLastArg(options::OPT_fropi, options::OPT_fno_ropi);
916   if (LastROPIArg && LastROPIArg->getOption().matches(options::OPT_fropi)) {
917     if (!EmbeddedPISupported)
918       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
919           << LastROPIArg->getSpelling() << Triple.str();
920     ROPI = true;
921   }
922   Arg *LastRWPIArg = Args.getLastArg(options::OPT_frwpi, options::OPT_fno_rwpi);
923   if (LastRWPIArg && LastRWPIArg->getOption().matches(options::OPT_frwpi)) {
924     if (!EmbeddedPISupported)
925       ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
926           << LastRWPIArg->getSpelling() << Triple.str();
927     RWPI = true;
928   }
929 
930   // ROPI and RWPI are not comaptible with PIC or PIE.
931   if ((ROPI || RWPI) && (PIC || PIE))
932     ToolChain.getDriver().Diag(diag::err_drv_ropi_rwpi_incompatible_with_pic);
933 
934   // When targettng MIPS64 with N64, the default is PIC, unless -mno-abicalls is
935   // used.
936   if ((Triple.getArch() == llvm::Triple::mips64 ||
937        Triple.getArch() == llvm::Triple::mips64el) &&
938       Args.hasArg(options::OPT_mno_abicalls))
939     return std::make_tuple(llvm::Reloc::Static, 0U, false);
940 
941   if (PIC)
942     return std::make_tuple(llvm::Reloc::PIC_, IsPICLevelTwo ? 2U : 1U, PIE);
943 
944   llvm::Reloc::Model RelocM = llvm::Reloc::Static;
945   if (ROPI && RWPI)
946     RelocM = llvm::Reloc::ROPI_RWPI;
947   else if (ROPI)
948     RelocM = llvm::Reloc::ROPI;
949   else if (RWPI)
950     RelocM = llvm::Reloc::RWPI;
951 
952   return std::make_tuple(RelocM, 0U, false);
953 }
954 
955 void tools::AddAssemblerKPIC(const ToolChain &ToolChain, const ArgList &Args,
956                              ArgStringList &CmdArgs) {
957   llvm::Reloc::Model RelocationModel;
958   unsigned PICLevel;
959   bool IsPIE;
960   std::tie(RelocationModel, PICLevel, IsPIE) = ParsePICArgs(ToolChain, Args);
961 
962   if (RelocationModel != llvm::Reloc::Static)
963     CmdArgs.push_back("-KPIC");
964 }
965 
966 /// \brief Determine whether Objective-C automated reference counting is
967 /// enabled.
968 bool tools::isObjCAutoRefCount(const ArgList &Args) {
969   return Args.hasFlag(options::OPT_fobjc_arc, options::OPT_fno_objc_arc, false);
970 }
971 
972 static void AddLibgcc(const llvm::Triple &Triple, const Driver &D,
973                       ArgStringList &CmdArgs, const ArgList &Args) {
974   bool isAndroid = Triple.isAndroid();
975   bool isCygMing = Triple.isOSCygMing();
976   bool IsIAMCU = Triple.isOSIAMCU();
977   bool StaticLibgcc = Args.hasArg(options::OPT_static_libgcc) ||
978                       Args.hasArg(options::OPT_static);
979   if (!D.CCCIsCXX())
980     CmdArgs.push_back("-lgcc");
981 
982   if (StaticLibgcc || isAndroid) {
983     if (D.CCCIsCXX())
984       CmdArgs.push_back("-lgcc");
985   } else {
986     if (!D.CCCIsCXX() && !isCygMing)
987       CmdArgs.push_back("--as-needed");
988     CmdArgs.push_back("-lgcc_s");
989     if (!D.CCCIsCXX() && !isCygMing)
990       CmdArgs.push_back("--no-as-needed");
991   }
992 
993   if (StaticLibgcc && !isAndroid && !IsIAMCU)
994     CmdArgs.push_back("-lgcc_eh");
995   else if (!Args.hasArg(options::OPT_shared) && D.CCCIsCXX())
996     CmdArgs.push_back("-lgcc");
997 
998   // According to Android ABI, we have to link with libdl if we are
999   // linking with non-static libgcc.
1000   //
1001   // NOTE: This fixes a link error on Android MIPS as well.  The non-static
1002   // libgcc for MIPS relies on _Unwind_Find_FDE and dl_iterate_phdr from libdl.
1003   if (isAndroid && !StaticLibgcc)
1004     CmdArgs.push_back("-ldl");
1005 }
1006 
1007 void tools::AddRunTimeLibs(const ToolChain &TC, const Driver &D,
1008                            ArgStringList &CmdArgs, const ArgList &Args) {
1009   // Make use of compiler-rt if --rtlib option is used
1010   ToolChain::RuntimeLibType RLT = TC.GetRuntimeLibType(Args);
1011 
1012   switch (RLT) {
1013   case ToolChain::RLT_CompilerRT:
1014     switch (TC.getTriple().getOS()) {
1015     default:
1016       llvm_unreachable("unsupported OS");
1017     case llvm::Triple::Win32:
1018     case llvm::Triple::Linux:
1019     case llvm::Triple::Fuchsia:
1020       CmdArgs.push_back(TC.getCompilerRTArgString(Args, "builtins"));
1021       break;
1022     }
1023     break;
1024   case ToolChain::RLT_Libgcc:
1025     // Make sure libgcc is not used under MSVC environment by default
1026     if (TC.getTriple().isKnownWindowsMSVCEnvironment()) {
1027       // Issue error diagnostic if libgcc is explicitly specified
1028       // through command line as --rtlib option argument.
1029       if (Args.hasArg(options::OPT_rtlib_EQ)) {
1030         TC.getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
1031             << Args.getLastArg(options::OPT_rtlib_EQ)->getValue() << "MSVC";
1032       }
1033     } else
1034       AddLibgcc(TC.getTriple(), D, CmdArgs, Args);
1035     break;
1036   }
1037 }
1038 
1039 /// Add OpenMP linker script arguments at the end of the argument list so that
1040 /// the fat binary is built by embedding each of the device images into the
1041 /// host. The linker script also defines a few symbols required by the code
1042 /// generation so that the images can be easily retrieved at runtime by the
1043 /// offloading library. This should be used only in tool chains that support
1044 /// linker scripts.
1045 void tools::AddOpenMPLinkerScript(const ToolChain &TC, Compilation &C,
1046                                   const InputInfo &Output,
1047                                   const InputInfoList &Inputs,
1048                                   const ArgList &Args, ArgStringList &CmdArgs,
1049                                   const JobAction &JA) {
1050 
1051   // If this is not an OpenMP host toolchain, we don't need to do anything.
1052   if (!JA.isHostOffloading(Action::OFK_OpenMP))
1053     return;
1054 
1055   // Create temporary linker script. Keep it if save-temps is enabled.
1056   const char *LKS;
1057   SmallString<256> Name = llvm::sys::path::filename(Output.getFilename());
1058   if (C.getDriver().isSaveTempsEnabled()) {
1059     llvm::sys::path::replace_extension(Name, "lk");
1060     LKS = C.getArgs().MakeArgString(Name.c_str());
1061   } else {
1062     llvm::sys::path::replace_extension(Name, "");
1063     Name = C.getDriver().GetTemporaryPath(Name, "lk");
1064     LKS = C.addTempFile(C.getArgs().MakeArgString(Name.c_str()));
1065   }
1066 
1067   // Add linker script option to the command.
1068   CmdArgs.push_back("-T");
1069   CmdArgs.push_back(LKS);
1070 
1071   // Create a buffer to write the contents of the linker script.
1072   std::string LksBuffer;
1073   llvm::raw_string_ostream LksStream(LksBuffer);
1074 
1075   // Get the OpenMP offload tool chains so that we can extract the triple
1076   // associated with each device input.
1077   auto OpenMPToolChains = C.getOffloadToolChains<Action::OFK_OpenMP>();
1078   assert(OpenMPToolChains.first != OpenMPToolChains.second &&
1079          "No OpenMP toolchains??");
1080 
1081   // Track the input file name and device triple in order to build the script,
1082   // inserting binaries in the designated sections.
1083   SmallVector<std::pair<std::string, const char *>, 8> InputBinaryInfo;
1084 
1085   // Add commands to embed target binaries. We ensure that each section and
1086   // image is 16-byte aligned. This is not mandatory, but increases the
1087   // likelihood of data to be aligned with a cache block in several main host
1088   // machines.
1089   LksStream << "/*\n";
1090   LksStream << "       OpenMP Offload Linker Script\n";
1091   LksStream << " *** Automatically generated by Clang ***\n";
1092   LksStream << "*/\n";
1093   LksStream << "TARGET(binary)\n";
1094   auto DTC = OpenMPToolChains.first;
1095   for (auto &II : Inputs) {
1096     const Action *A = II.getAction();
1097     // Is this a device linking action?
1098     if (A && isa<LinkJobAction>(A) &&
1099         A->isDeviceOffloading(Action::OFK_OpenMP)) {
1100       assert(DTC != OpenMPToolChains.second &&
1101              "More device inputs than device toolchains??");
1102       InputBinaryInfo.push_back(std::make_pair(
1103           DTC->second->getTriple().normalize(), II.getFilename()));
1104       ++DTC;
1105       LksStream << "INPUT(" << II.getFilename() << ")\n";
1106     }
1107   }
1108 
1109   assert(DTC == OpenMPToolChains.second &&
1110          "Less device inputs than device toolchains??");
1111 
1112   LksStream << "SECTIONS\n";
1113   LksStream << "{\n";
1114 
1115   // Put each target binary into a separate section.
1116   for (const auto &BI : InputBinaryInfo) {
1117     LksStream << "  .omp_offloading." << BI.first << " :\n";
1118     LksStream << "  ALIGN(0x10)\n";
1119     LksStream << "  {\n";
1120     LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_start." << BI.first
1121               << " = .);\n";
1122     LksStream << "    " << BI.second << "\n";
1123     LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_end." << BI.first
1124               << " = .);\n";
1125     LksStream << "  }\n";
1126   }
1127 
1128   // Add commands to define host entries begin and end. We use 1-byte subalign
1129   // so that the linker does not add any padding and the elements in this
1130   // section form an array.
1131   LksStream << "  .omp_offloading.entries :\n";
1132   LksStream << "  ALIGN(0x10)\n";
1133   LksStream << "  SUBALIGN(0x01)\n";
1134   LksStream << "  {\n";
1135   LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_begin = .);\n";
1136   LksStream << "    *(.omp_offloading.entries)\n";
1137   LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_end = .);\n";
1138   LksStream << "  }\n";
1139   LksStream << "}\n";
1140   LksStream << "INSERT BEFORE .data\n";
1141   LksStream.flush();
1142 
1143   // Dump the contents of the linker script if the user requested that. We
1144   // support this option to enable testing of behavior with -###.
1145   if (C.getArgs().hasArg(options::OPT_fopenmp_dump_offload_linker_script))
1146     llvm::errs() << LksBuffer;
1147 
1148   // If this is a dry run, do not create the linker script file.
1149   if (C.getArgs().hasArg(options::OPT__HASH_HASH_HASH))
1150     return;
1151 
1152   // Open script file and write the contents.
1153   std::error_code EC;
1154   llvm::raw_fd_ostream Lksf(LKS, EC, llvm::sys::fs::F_None);
1155 
1156   if (EC) {
1157     C.getDriver().Diag(clang::diag::err_unable_to_make_temp) << EC.message();
1158     return;
1159   }
1160 
1161   Lksf << LksBuffer;
1162 }
1163