1 //===- lli.cpp - LLVM Interpreter / Dynamic compiler ----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This utility provides a simple wrapper around the LLVM Execution Engines,
11 // which allow the direct execution of LLVM programs through a Just-In-Time
12 // compiler, or through an interpreter if no JIT is available for this platform.
14 //===----------------------------------------------------------------------===//
16 #include "OrcLazyJIT.h"
17 #include "RemoteJITUtils.h"
18 #include "llvm/IR/LLVMContext.h"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/Bitcode/BitcodeReader.h"
22 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
23 #include "llvm/ExecutionEngine/GenericValue.h"
24 #include "llvm/ExecutionEngine/Interpreter.h"
25 #include "llvm/ExecutionEngine/JITEventListener.h"
26 #include "llvm/ExecutionEngine/MCJIT.h"
27 #include "llvm/ExecutionEngine/ObjectCache.h"
28 #include "llvm/ExecutionEngine/OrcMCJITReplacement.h"
29 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
30 #include "llvm/ExecutionEngine/Orc/OrcRemoteTargetClient.h"
31 #include "llvm/IR/IRBuilder.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/Type.h"
34 #include "llvm/IR/TypeBuilder.h"
35 #include "llvm/IRReader/IRReader.h"
36 #include "llvm/Object/Archive.h"
37 #include "llvm/Object/ObjectFile.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/DynamicLibrary.h"
41 #include "llvm/Support/Format.h"
42 #include "llvm/Support/ManagedStatic.h"
43 #include "llvm/Support/MathExtras.h"
44 #include "llvm/Support/Memory.h"
45 #include "llvm/Support/MemoryBuffer.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/PluginLoader.h"
48 #include "llvm/Support/PrettyStackTrace.h"
49 #include "llvm/Support/Process.h"
50 #include "llvm/Support/Program.h"
51 #include "llvm/Support/Signals.h"
52 #include "llvm/Support/SourceMgr.h"
53 #include "llvm/Support/TargetSelect.h"
54 #include "llvm/Support/raw_ostream.h"
55 #include "llvm/Transforms/Instrumentation.h"
59 #include <cygwin/version.h>
60 #if defined(CYGWIN_VERSION_DLL_MAJOR) && CYGWIN_VERSION_DLL_MAJOR<1007
61 #define DO_NOTHING_ATEXIT 1
67 #define DEBUG_TYPE "lli"
71 enum class JITKind { MCJIT, OrcMCJITReplacement, OrcLazy };
74 InputFile(cl::desc("<input bitcode>"), cl::Positional, cl::init("-"));
77 InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
79 cl::opt<bool> ForceInterpreter("force-interpreter",
80 cl::desc("Force interpretation: disable JIT"),
83 cl::opt<JITKind> UseJITKind("jit-kind",
84 cl::desc("Choose underlying JIT kind."),
85 cl::init(JITKind::MCJIT),
87 clEnumValN(JITKind::MCJIT, "mcjit",
89 clEnumValN(JITKind::OrcMCJITReplacement,
91 "Orc-based MCJIT replacement"),
92 clEnumValN(JITKind::OrcLazy,
94 "Orc-based lazy JIT.")));
96 // The MCJIT supports building for a target address space separate from
97 // the JIT compilation process. Use a forked process and a copying
98 // memory manager with IPC to execute using this functionality.
99 cl::opt<bool> RemoteMCJIT("remote-mcjit",
100 cl::desc("Execute MCJIT'ed code in a separate process."),
103 // Manually specify the child process for remote execution. This overrides
104 // the simulated remote execution that allocates address space for child
105 // execution. The child process will be executed and will communicate with
106 // lli via stdin/stdout pipes.
108 ChildExecPath("mcjit-remote-process",
109 cl::desc("Specify the filename of the process to launch "
110 "for remote MCJIT execution. If none is specified,"
111 "\n\tremote execution will be simulated in-process."),
112 cl::value_desc("filename"), cl::init(""));
114 // Determine optimization level.
117 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
118 "(default = '-O2')"),
124 TargetTriple("mtriple", cl::desc("Override target triple for module"));
128 cl::desc("Architecture to generate assembly for (see --version)"));
132 cl::desc("Target a specific cpu type (-mcpu=help for details)"),
133 cl::value_desc("cpu-name"),
136 cl::list<std::string>
139 cl::desc("Target specific attributes (-mattr=help for details)"),
140 cl::value_desc("a1,+a2,-a3,..."));
143 EntryFunc("entry-function",
144 cl::desc("Specify the entry function (default = 'main') "
145 "of the executable"),
146 cl::value_desc("function"),
149 cl::list<std::string>
150 ExtraModules("extra-module",
151 cl::desc("Extra modules to be loaded"),
152 cl::value_desc("input bitcode"));
154 cl::list<std::string>
155 ExtraObjects("extra-object",
156 cl::desc("Extra object files to be loaded"),
157 cl::value_desc("input object"));
159 cl::list<std::string>
160 ExtraArchives("extra-archive",
161 cl::desc("Extra archive files to be loaded"),
162 cl::value_desc("input archive"));
165 EnableCacheManager("enable-cache-manager",
166 cl::desc("Use cache manager to save/load mdoules"),
170 ObjectCacheDir("object-cache-dir",
171 cl::desc("Directory to store cached object files "
172 "(must be user writable)"),
176 FakeArgv0("fake-argv0",
177 cl::desc("Override the 'argv[0]' value passed into the executing"
178 " program"), cl::value_desc("executable"));
181 DisableCoreFiles("disable-core-files", cl::Hidden,
182 cl::desc("Disable emission of core files if possible"));
185 NoLazyCompilation("disable-lazy-compilation",
186 cl::desc("Disable JIT lazy compilation"),
189 cl::opt<Reloc::Model> RelocModel(
190 "relocation-model", cl::desc("Choose relocation model"),
192 clEnumValN(Reloc::Static, "static", "Non-relocatable code"),
193 clEnumValN(Reloc::PIC_, "pic",
194 "Fully relocatable, position independent code"),
195 clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
196 "Relocatable external references, non-relocatable code")));
198 cl::opt<llvm::CodeModel::Model>
199 CMModel("code-model",
200 cl::desc("Choose code model"),
201 cl::init(CodeModel::JITDefault),
202 cl::values(clEnumValN(CodeModel::JITDefault, "default",
203 "Target default JIT code model"),
204 clEnumValN(CodeModel::Small, "small",
206 clEnumValN(CodeModel::Kernel, "kernel",
207 "Kernel code model"),
208 clEnumValN(CodeModel::Medium, "medium",
209 "Medium code model"),
210 clEnumValN(CodeModel::Large, "large",
211 "Large code model")));
214 GenerateSoftFloatCalls("soft-float",
215 cl::desc("Generate software floating point library calls"),
218 cl::opt<llvm::FloatABI::ABIType>
219 FloatABIForCalls("float-abi",
220 cl::desc("Choose float ABI type"),
221 cl::init(FloatABI::Default),
223 clEnumValN(FloatABI::Default, "default",
224 "Target default float ABI type"),
225 clEnumValN(FloatABI::Soft, "soft",
226 "Soft float ABI (implied by -soft-float)"),
227 clEnumValN(FloatABI::Hard, "hard",
228 "Hard float ABI (uses FP registers)")));
230 ExitOnError ExitOnErr;
233 //===----------------------------------------------------------------------===//
236 // This object cache implementation writes cached objects to disk to the
237 // directory specified by CacheDir, using a filename provided in the module
238 // descriptor. The cache tries to load a saved object using that path if the
239 // file exists. CacheDir defaults to "", in which case objects are cached
240 // alongside their originating bitcodes.
242 class LLIObjectCache : public ObjectCache {
244 LLIObjectCache(const std::string& CacheDir) : CacheDir(CacheDir) {
245 // Add trailing '/' to cache dir if necessary.
246 if (!this->CacheDir.empty() &&
247 this->CacheDir[this->CacheDir.size() - 1] != '/')
248 this->CacheDir += '/';
250 ~LLIObjectCache() override {}
252 void notifyObjectCompiled(const Module *M, MemoryBufferRef Obj) override {
253 const std::string &ModuleID = M->getModuleIdentifier();
254 std::string CacheName;
255 if (!getCacheFilename(ModuleID, CacheName))
257 if (!CacheDir.empty()) { // Create user-defined cache dir.
258 SmallString<128> dir(sys::path::parent_path(CacheName));
259 sys::fs::create_directories(Twine(dir));
262 raw_fd_ostream outfile(CacheName, EC, sys::fs::F_None);
263 outfile.write(Obj.getBufferStart(), Obj.getBufferSize());
267 std::unique_ptr<MemoryBuffer> getObject(const Module* M) override {
268 const std::string &ModuleID = M->getModuleIdentifier();
269 std::string CacheName;
270 if (!getCacheFilename(ModuleID, CacheName))
272 // Load the object from the cache filename
273 ErrorOr<std::unique_ptr<MemoryBuffer>> IRObjectBuffer =
274 MemoryBuffer::getFile(CacheName, -1, false);
275 // If the file isn't there, that's OK.
278 // MCJIT will want to write into this buffer, and we don't want that
279 // because the file has probably just been mmapped. Instead we make
280 // a copy. The filed-based buffer will be released when it goes
282 return MemoryBuffer::getMemBufferCopy(IRObjectBuffer.get()->getBuffer());
286 std::string CacheDir;
288 bool getCacheFilename(const std::string &ModID, std::string &CacheName) {
289 std::string Prefix("file:");
290 size_t PrefixLength = Prefix.length();
291 if (ModID.substr(0, PrefixLength) != Prefix)
293 std::string CacheSubdir = ModID.substr(PrefixLength);
295 // Transform "X:\foo" => "/X\foo" for convenience.
296 if (isalpha(CacheSubdir[0]) && CacheSubdir[1] == ':') {
297 CacheSubdir[1] = CacheSubdir[0];
298 CacheSubdir[0] = '/';
301 CacheName = CacheDir + CacheSubdir;
302 size_t pos = CacheName.rfind('.');
303 CacheName.replace(pos, CacheName.length() - pos, ".o");
308 // On Mingw and Cygwin, an external symbol named '__main' is called from the
309 // generated 'main' function to allow static initialization. To avoid linking
310 // problems with remote targets (because lli's remote target support does not
311 // currently handle external linking) we add a secondary module which defines
312 // an empty '__main' function.
313 static void addCygMingExtraModule(ExecutionEngine &EE, LLVMContext &Context,
314 StringRef TargetTripleStr) {
315 IRBuilder<> Builder(Context);
316 Triple TargetTriple(TargetTripleStr);
318 // Create a new module.
319 std::unique_ptr<Module> M = make_unique<Module>("CygMingHelper", Context);
320 M->setTargetTriple(TargetTripleStr);
322 // Create an empty function named "__main".
324 if (TargetTriple.isArch64Bit()) {
325 Result = Function::Create(
326 TypeBuilder<int64_t(void), false>::get(Context),
327 GlobalValue::ExternalLinkage, "__main", M.get());
329 Result = Function::Create(
330 TypeBuilder<int32_t(void), false>::get(Context),
331 GlobalValue::ExternalLinkage, "__main", M.get());
333 BasicBlock *BB = BasicBlock::Create(Context, "__main", Result);
334 Builder.SetInsertPoint(BB);
336 if (TargetTriple.isArch64Bit())
337 ReturnVal = ConstantInt::get(Context, APInt(64, 0));
339 ReturnVal = ConstantInt::get(Context, APInt(32, 0));
340 Builder.CreateRet(ReturnVal);
342 // Add this new module to the ExecutionEngine.
343 EE.addModule(std::move(M));
346 CodeGenOpt::Level getOptLevel() {
349 errs() << "lli: Invalid optimization level.\n";
351 case '0': return CodeGenOpt::None;
352 case '1': return CodeGenOpt::Less;
354 case '2': return CodeGenOpt::Default;
355 case '3': return CodeGenOpt::Aggressive;
357 llvm_unreachable("Unrecognized opt level.");
360 LLVM_ATTRIBUTE_NORETURN
361 static void reportError(SMDiagnostic Err, const char *ProgName) {
362 Err.print(ProgName, errs());
366 //===----------------------------------------------------------------------===//
367 // main Driver function
369 int main(int argc, char **argv, char * const *envp) {
370 sys::PrintStackTraceOnErrorSignal(argv[0]);
371 PrettyStackTraceProgram X(argc, argv);
373 atexit(llvm_shutdown); // Call llvm_shutdown() on exit.
376 ExitOnErr.setBanner(std::string(argv[0]) + ": ");
378 // If we have a native target, initialize it to ensure it is linked in and
379 // usable by the JIT.
380 InitializeNativeTarget();
381 InitializeNativeTargetAsmPrinter();
382 InitializeNativeTargetAsmParser();
384 cl::ParseCommandLineOptions(argc, argv,
385 "llvm interpreter & dynamic compiler\n");
387 // If the user doesn't want core files, disable them.
388 if (DisableCoreFiles)
389 sys::Process::PreventCoreFiles();
393 // Load the bitcode...
395 std::unique_ptr<Module> Owner = parseIRFile(InputFile, Err, Context);
396 Module *Mod = Owner.get();
398 reportError(Err, argv[0]);
400 if (UseJITKind == JITKind::OrcLazy) {
401 std::vector<std::unique_ptr<Module>> Ms;
402 Ms.push_back(std::move(Owner));
403 for (auto &ExtraMod : ExtraModules) {
404 Ms.push_back(parseIRFile(ExtraMod, Err, Context));
406 reportError(Err, argv[0]);
408 std::vector<std::string> Args;
409 Args.push_back(InputFile);
410 for (auto &Arg : InputArgv)
412 return runOrcLazyJIT(std::move(Ms), Args);
415 if (EnableCacheManager) {
416 std::string CacheName("file:");
417 CacheName.append(InputFile);
418 Mod->setModuleIdentifier(CacheName);
421 // If not jitting lazily, load the whole bitcode file eagerly too.
422 if (NoLazyCompilation) {
423 // Use *argv instead of argv[0] to work around a wrong GCC warning.
424 ExitOnError ExitOnErr(std::string(*argv) +
425 ": bitcode didn't read correctly: ");
426 ExitOnErr(Mod->materializeAll());
429 std::string ErrorMsg;
430 EngineBuilder builder(std::move(Owner));
431 builder.setMArch(MArch);
432 builder.setMCPU(MCPU);
433 builder.setMAttrs(MAttrs);
434 if (RelocModel.getNumOccurrences())
435 builder.setRelocationModel(RelocModel);
436 builder.setCodeModel(CMModel);
437 builder.setErrorStr(&ErrorMsg);
438 builder.setEngineKind(ForceInterpreter
439 ? EngineKind::Interpreter
441 builder.setUseOrcMCJITReplacement(UseJITKind == JITKind::OrcMCJITReplacement);
443 // If we are supposed to override the target triple, do so now.
444 if (!TargetTriple.empty())
445 Mod->setTargetTriple(Triple::normalize(TargetTriple));
447 // Enable MCJIT if desired.
448 RTDyldMemoryManager *RTDyldMM = nullptr;
449 if (!ForceInterpreter) {
451 RTDyldMM = new ForwardingMemoryManager();
453 RTDyldMM = new SectionMemoryManager();
455 // Deliberately construct a temp std::unique_ptr to pass in. Do not null out
456 // RTDyldMM: We still use it below, even though we don't own it.
457 builder.setMCJITMemoryManager(
458 std::unique_ptr<RTDyldMemoryManager>(RTDyldMM));
459 } else if (RemoteMCJIT) {
460 errs() << "error: Remote process execution does not work with the "
465 builder.setOptLevel(getOptLevel());
467 TargetOptions Options;
468 if (FloatABIForCalls != FloatABI::Default)
469 Options.FloatABIType = FloatABIForCalls;
471 builder.setTargetOptions(Options);
473 std::unique_ptr<ExecutionEngine> EE(builder.create());
475 if (!ErrorMsg.empty())
476 errs() << argv[0] << ": error creating EE: " << ErrorMsg << "\n";
478 errs() << argv[0] << ": unknown error creating EE!\n";
482 std::unique_ptr<LLIObjectCache> CacheManager;
483 if (EnableCacheManager) {
484 CacheManager.reset(new LLIObjectCache(ObjectCacheDir));
485 EE->setObjectCache(CacheManager.get());
488 // Load any additional modules specified on the command line.
489 for (unsigned i = 0, e = ExtraModules.size(); i != e; ++i) {
490 std::unique_ptr<Module> XMod = parseIRFile(ExtraModules[i], Err, Context);
492 reportError(Err, argv[0]);
493 if (EnableCacheManager) {
494 std::string CacheName("file:");
495 CacheName.append(ExtraModules[i]);
496 XMod->setModuleIdentifier(CacheName);
498 EE->addModule(std::move(XMod));
501 for (unsigned i = 0, e = ExtraObjects.size(); i != e; ++i) {
502 Expected<object::OwningBinary<object::ObjectFile>> Obj =
503 object::ObjectFile::createObjectFile(ExtraObjects[i]);
505 // TODO: Actually report errors helpfully.
506 consumeError(Obj.takeError());
507 reportError(Err, argv[0]);
509 object::OwningBinary<object::ObjectFile> &O = Obj.get();
510 EE->addObjectFile(std::move(O));
513 for (unsigned i = 0, e = ExtraArchives.size(); i != e; ++i) {
514 ErrorOr<std::unique_ptr<MemoryBuffer>> ArBufOrErr =
515 MemoryBuffer::getFileOrSTDIN(ExtraArchives[i]);
517 reportError(Err, argv[0]);
518 std::unique_ptr<MemoryBuffer> &ArBuf = ArBufOrErr.get();
520 Expected<std::unique_ptr<object::Archive>> ArOrErr =
521 object::Archive::create(ArBuf->getMemBufferRef());
524 raw_string_ostream OS(Buf);
525 logAllUnhandledErrors(ArOrErr.takeError(), OS, "");
530 std::unique_ptr<object::Archive> &Ar = ArOrErr.get();
532 object::OwningBinary<object::Archive> OB(std::move(Ar), std::move(ArBuf));
534 EE->addArchive(std::move(OB));
537 // If the target is Cygwin/MingW and we are generating remote code, we
538 // need an extra module to help out with linking.
539 if (RemoteMCJIT && Triple(Mod->getTargetTriple()).isOSCygMing()) {
540 addCygMingExtraModule(*EE, Context, Mod->getTargetTriple());
543 // The following functions have no effect if their respective profiling
544 // support wasn't enabled in the build configuration.
545 EE->RegisterJITEventListener(
546 JITEventListener::createOProfileJITEventListener());
547 EE->RegisterJITEventListener(
548 JITEventListener::createIntelJITEventListener());
550 if (!NoLazyCompilation && RemoteMCJIT) {
551 errs() << "warning: remote mcjit does not support lazy compilation\n";
552 NoLazyCompilation = true;
554 EE->DisableLazyCompilation(NoLazyCompilation);
556 // If the user specifically requested an argv[0] to pass into the program,
558 if (!FakeArgv0.empty()) {
559 InputFile = static_cast<std::string>(FakeArgv0);
561 // Otherwise, if there is a .bc suffix on the executable strip it off, it
562 // might confuse the program.
563 if (StringRef(InputFile).endswith(".bc"))
564 InputFile.erase(InputFile.length() - 3);
567 // Add the module's name to the start of the vector of arguments to main().
568 InputArgv.insert(InputArgv.begin(), InputFile);
570 // Call the main function from M as if its signature were:
571 // int main (int argc, char **argv, const char **envp)
572 // using the contents of Args to determine argc & argv, and the contents of
573 // EnvVars to determine envp.
575 Function *EntryFn = Mod->getFunction(EntryFunc);
577 errs() << '\'' << EntryFunc << "\' function not found in module.\n";
581 // Reset errno to zero on entry to main.
586 // Sanity check use of remote-jit: LLI currently only supports use of the
587 // remote JIT on Unix platforms.
590 errs() << "Warning: host does not support external remote targets.\n"
591 << " Defaulting to local execution\n";
594 if (ChildExecPath.empty()) {
595 errs() << "-remote-mcjit requires -mcjit-remote-process.\n";
597 } else if (!sys::fs::can_execute(ChildExecPath)) {
598 errs() << "Unable to find usable child executable: '" << ChildExecPath
606 // If the program doesn't explicitly call exit, we will need the Exit
607 // function later on to make an explicit call, so get the function now.
608 Constant *Exit = Mod->getOrInsertFunction("exit", Type::getVoidTy(Context),
609 Type::getInt32Ty(Context),
612 // Run static constructors.
613 if (!ForceInterpreter) {
614 // Give MCJIT a chance to apply relocations and set page permissions.
615 EE->finalizeObject();
617 EE->runStaticConstructorsDestructors(false);
619 // Trigger compilation separately so code regions that need to be
620 // invalidated will be known.
621 (void)EE->getPointerToFunction(EntryFn);
622 // Clear instruction cache before code will be executed.
624 static_cast<SectionMemoryManager*>(RTDyldMM)->invalidateInstructionCache();
627 Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
629 // Run static destructors.
630 EE->runStaticConstructorsDestructors(true);
632 // If the program didn't call exit explicitly, we should call it now.
633 // This ensures that any atexit handlers get called correctly.
634 if (Function *ExitF = dyn_cast<Function>(Exit)) {
635 std::vector<GenericValue> Args;
636 GenericValue ResultGV;
637 ResultGV.IntVal = APInt(32, Result);
638 Args.push_back(ResultGV);
639 EE->runFunction(ExitF, Args);
640 errs() << "ERROR: exit(" << Result << ") returned!\n";
643 errs() << "ERROR: exit defined with wrong prototype!\n";
647 // else == "if (RemoteMCJIT)"
649 // Remote target MCJIT doesn't (yet) support static constructors. No reason
650 // it couldn't. This is a limitation of the LLI implemantation, not the
651 // MCJIT itself. FIXME.
653 // Lanch the remote process and get a channel to it.
654 std::unique_ptr<FDRawChannel> C = launchRemote();
656 errs() << "Failed to launch remote JIT.\n";
660 // Create a remote target client running over the channel.
661 typedef orc::remote::OrcRemoteTargetClient<orc::rpc::RawByteChannel>
663 auto R = ExitOnErr(MyRemote::Create(*C));
665 // Create a remote memory manager.
666 std::unique_ptr<MyRemote::RCMemoryManager> RemoteMM;
667 ExitOnErr(R->createRemoteMemoryManager(RemoteMM));
669 // Forward MCJIT's memory manager calls to the remote memory manager.
670 static_cast<ForwardingMemoryManager*>(RTDyldMM)->setMemMgr(
671 std::move(RemoteMM));
673 // Forward MCJIT's symbol resolution calls to the remote.
674 static_cast<ForwardingMemoryManager*>(RTDyldMM)->setResolver(
675 orc::createLambdaResolver(
676 [](const std::string &Name) { return nullptr; },
677 [&](const std::string &Name) {
678 if (auto Addr = ExitOnErr(R->getSymbolAddress(Name)))
679 return JITSymbol(Addr, JITSymbolFlags::Exported);
680 return JITSymbol(nullptr);
684 // Grab the target address of the JIT'd main function on the remote and call
686 // FIXME: argv and envp handling.
687 JITTargetAddress Entry = EE->getFunctionAddress(EntryFn->getName().str());
688 EE->finalizeObject();
689 DEBUG(dbgs() << "Executing '" << EntryFn->getName() << "' at 0x"
690 << format("%llx", Entry) << "\n");
691 Result = ExitOnErr(R->callIntVoid(Entry));
693 // Like static constructors, the remote target MCJIT support doesn't handle
694 // this yet. It could. FIXME.
696 // Delete the EE - we need to tear it down *before* we terminate the session
697 // with the remote, otherwise it'll crash when it tries to release resources
698 // on a remote that has already been disconnected.
701 // Signal the remote target that we're done JITing.
702 ExitOnErr(R->terminateSession());
708 std::unique_ptr<FDRawChannel> launchRemote() {
710 llvm_unreachable("launchRemote not supported on non-Unix platforms");
716 if (pipe(PipeFD[0]) != 0 || pipe(PipeFD[1]) != 0)
717 perror("Error creating pipe: ");
724 // Close the parent ends of the pipes
729 // Execute the child process.
730 std::unique_ptr<char[]> ChildPath, ChildIn, ChildOut;
732 ChildPath.reset(new char[ChildExecPath.size() + 1]);
733 std::copy(ChildExecPath.begin(), ChildExecPath.end(), &ChildPath[0]);
734 ChildPath[ChildExecPath.size()] = '\0';
735 std::string ChildInStr = utostr(PipeFD[0][0]);
736 ChildIn.reset(new char[ChildInStr.size() + 1]);
737 std::copy(ChildInStr.begin(), ChildInStr.end(), &ChildIn[0]);
738 ChildIn[ChildInStr.size()] = '\0';
739 std::string ChildOutStr = utostr(PipeFD[1][1]);
740 ChildOut.reset(new char[ChildOutStr.size() + 1]);
741 std::copy(ChildOutStr.begin(), ChildOutStr.end(), &ChildOut[0]);
742 ChildOut[ChildOutStr.size()] = '\0';
745 char * const args[] = { &ChildPath[0], &ChildIn[0], &ChildOut[0], nullptr };
746 int rc = execv(ChildExecPath.c_str(), args);
748 perror("Error executing child process: ");
749 llvm_unreachable("Error executing child process");
751 // else we're the parent...
753 // Close the child ends of the pipes
757 // Return an RPC channel connected to our end of the pipes.
758 return llvm::make_unique<FDRawChannel>(PipeFD[1][0], PipeFD[0][1]);