1 //===------- SimpleEPCServer.cpp - EPC over simple abstract channel -------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/ExecutionEngine/Orc/TargetProcess/SimpleRemoteEPCServer.h"
10 
11 #include "llvm/ExecutionEngine/Orc/Shared/TargetProcessControlTypes.h"
12 #include "llvm/Support/FormatVariadic.h"
13 #include "llvm/Support/Host.h"
14 #include "llvm/Support/Process.h"
15 
16 #include "OrcRTBootstrap.h"
17 
18 #define DEBUG_TYPE "orc"
19 
20 using namespace llvm::orc::shared;
21 
22 namespace llvm {
23 namespace orc {
24 
25 ExecutorBootstrapService::~ExecutorBootstrapService() {}
26 
27 SimpleRemoteEPCServer::Dispatcher::~Dispatcher() {}
28 
29 #if LLVM_ENABLE_THREADS
30 void SimpleRemoteEPCServer::ThreadDispatcher::dispatch(
31     unique_function<void()> Work) {
32   {
33     std::lock_guard<std::mutex> Lock(DispatchMutex);
34     if (!Running)
35       return;
36     ++Outstanding;
37   }
38 
39   std::thread([this, Work = std::move(Work)]() mutable {
40     Work();
41     std::lock_guard<std::mutex> Lock(DispatchMutex);
42     --Outstanding;
43     OutstandingCV.notify_all();
44   }).detach();
45 }
46 
47 void SimpleRemoteEPCServer::ThreadDispatcher::shutdown() {
48   std::unique_lock<std::mutex> Lock(DispatchMutex);
49   Running = false;
50   OutstandingCV.wait(Lock, [this]() { return Outstanding == 0; });
51 }
52 #endif
53 
54 StringMap<ExecutorAddress> SimpleRemoteEPCServer::defaultBootstrapSymbols() {
55   StringMap<ExecutorAddress> DBS;
56   rt_bootstrap::addTo(DBS);
57   DBS["__llvm_orc_load_dylib"] = ExecutorAddress::fromPtr(&loadDylibWrapper);
58   DBS["__llvm_orc_lookup_symbols"] =
59       ExecutorAddress::fromPtr(&lookupSymbolsWrapper);
60   return DBS;
61 }
62 
63 Expected<SimpleRemoteEPCTransportClient::HandleMessageAction>
64 SimpleRemoteEPCServer::handleMessage(SimpleRemoteEPCOpcode OpC, uint64_t SeqNo,
65                                      ExecutorAddress TagAddr,
66                                      SimpleRemoteEPCArgBytesVector ArgBytes) {
67   using UT = std::underlying_type_t<SimpleRemoteEPCOpcode>;
68   if (static_cast<UT>(OpC) > static_cast<UT>(SimpleRemoteEPCOpcode::LastOpC))
69     return make_error<StringError>("Unexpected opcode",
70                                    inconvertibleErrorCode());
71 
72   // TODO: Clean detach message?
73   switch (OpC) {
74   case SimpleRemoteEPCOpcode::Setup:
75     return make_error<StringError>("Unexpected Setup opcode",
76                                    inconvertibleErrorCode());
77   case SimpleRemoteEPCOpcode::Hangup:
78     return SimpleRemoteEPCTransportClient::EndSession;
79   case SimpleRemoteEPCOpcode::Result:
80     if (auto Err = handleResult(SeqNo, TagAddr, std::move(ArgBytes)))
81       return std::move(Err);
82     break;
83   case SimpleRemoteEPCOpcode::CallWrapper:
84     handleCallWrapper(SeqNo, TagAddr, std::move(ArgBytes));
85     break;
86   }
87   return ContinueSession;
88 }
89 
90 Error SimpleRemoteEPCServer::waitForDisconnect() {
91   std::unique_lock<std::mutex> Lock(ServerStateMutex);
92   ShutdownCV.wait(Lock, [this]() { return RunState == ServerShutDown; });
93   return std::move(ShutdownErr);
94 }
95 
96 void SimpleRemoteEPCServer::handleDisconnect(Error Err) {
97   PendingJITDispatchResultsMap TmpPending;
98 
99   {
100     std::lock_guard<std::mutex> Lock(ServerStateMutex);
101     std::swap(TmpPending, PendingJITDispatchResults);
102     RunState = ServerShuttingDown;
103   }
104 
105   // Send out-of-band errors to any waiting threads.
106   for (auto &KV : TmpPending)
107     KV.second->set_value(
108         shared::WrapperFunctionResult::createOutOfBandError("disconnecting"));
109 
110   // TODO: Free attached resources.
111   // 1. Close libraries in DylibHandles.
112 
113   // Wait for dispatcher to clear.
114   D->shutdown();
115 
116   std::lock_guard<std::mutex> Lock(ServerStateMutex);
117   ShutdownErr = joinErrors(std::move(ShutdownErr), std::move(Err));
118   RunState = ServerShutDown;
119   ShutdownCV.notify_all();
120 }
121 
122 Error SimpleRemoteEPCServer::sendSetupMessage(
123     StringMap<ExecutorAddress> BootstrapSymbols) {
124 
125   using namespace SimpleRemoteEPCDefaultBootstrapSymbolNames;
126 
127   std::vector<char> SetupPacket;
128   SimpleRemoteEPCExecutorInfo EI;
129   EI.TargetTriple = sys::getProcessTriple();
130   if (auto PageSize = sys::Process::getPageSize())
131     EI.PageSize = *PageSize;
132   else
133     return PageSize.takeError();
134   EI.BootstrapSymbols = std::move(BootstrapSymbols);
135 
136   assert(!EI.BootstrapSymbols.count(ExecutorSessionObjectName) &&
137          "Dispatch context name should not be set");
138   assert(!EI.BootstrapSymbols.count(DispatchFnName) &&
139          "Dispatch function name should not be set");
140   EI.BootstrapSymbols[ExecutorSessionObjectName] =
141       ExecutorAddress::fromPtr(this);
142   EI.BootstrapSymbols[DispatchFnName] =
143       ExecutorAddress::fromPtr(jitDispatchEntry);
144 
145   using SPSSerialize =
146       shared::SPSArgList<shared::SPSSimpleRemoteEPCExecutorInfo>;
147   auto SetupPacketBytes =
148       shared::WrapperFunctionResult::allocate(SPSSerialize::size(EI));
149   shared::SPSOutputBuffer OB(SetupPacketBytes.data(), SetupPacketBytes.size());
150   if (!SPSSerialize::serialize(OB, EI))
151     return make_error<StringError>("Could not send setup packet",
152                                    inconvertibleErrorCode());
153 
154   return T->sendMessage(SimpleRemoteEPCOpcode::Setup, 0, ExecutorAddress(),
155                         {SetupPacketBytes.data(), SetupPacketBytes.size()});
156 }
157 
158 Error SimpleRemoteEPCServer::handleResult(
159     uint64_t SeqNo, ExecutorAddress TagAddr,
160     SimpleRemoteEPCArgBytesVector ArgBytes) {
161   std::promise<shared::WrapperFunctionResult> *P = nullptr;
162   {
163     std::lock_guard<std::mutex> Lock(ServerStateMutex);
164     auto I = PendingJITDispatchResults.find(SeqNo);
165     if (I == PendingJITDispatchResults.end())
166       return make_error<StringError>("No call for sequence number " +
167                                          Twine(SeqNo),
168                                      inconvertibleErrorCode());
169     P = I->second;
170     PendingJITDispatchResults.erase(I);
171     releaseSeqNo(SeqNo);
172   }
173   auto R = shared::WrapperFunctionResult::allocate(ArgBytes.size());
174   memcpy(R.data(), ArgBytes.data(), ArgBytes.size());
175   P->set_value(std::move(R));
176   return Error::success();
177 }
178 
179 void SimpleRemoteEPCServer::handleCallWrapper(
180     uint64_t RemoteSeqNo, ExecutorAddress TagAddr,
181     SimpleRemoteEPCArgBytesVector ArgBytes) {
182   D->dispatch([this, RemoteSeqNo, TagAddr, ArgBytes = std::move(ArgBytes)]() {
183     using WrapperFnTy =
184         shared::detail::CWrapperFunctionResult (*)(const char *, size_t);
185     auto *Fn = TagAddr.toPtr<WrapperFnTy>();
186     shared::WrapperFunctionResult ResultBytes(
187         Fn(ArgBytes.data(), ArgBytes.size()));
188     if (auto Err = T->sendMessage(SimpleRemoteEPCOpcode::Result, RemoteSeqNo,
189                                   ExecutorAddress(),
190                                   {ResultBytes.data(), ResultBytes.size()}))
191       ReportError(std::move(Err));
192   });
193 }
194 
195 shared::detail::CWrapperFunctionResult
196 SimpleRemoteEPCServer::loadDylibWrapper(const char *ArgData, size_t ArgSize) {
197   return shared::WrapperFunction<shared::SPSLoadDylibSignature>::handle(
198              ArgData, ArgSize,
199              [](ExecutorAddress ExecutorSessionObj, std::string Path,
200                 uint64_t Flags) -> Expected<uint64_t> {
201                return ExecutorSessionObj.toPtr<SimpleRemoteEPCServer *>()
202                    ->loadDylib(Path, Flags);
203              })
204       .release();
205 }
206 
207 shared::detail::CWrapperFunctionResult
208 SimpleRemoteEPCServer::lookupSymbolsWrapper(const char *ArgData,
209                                             size_t ArgSize) {
210   return shared::WrapperFunction<shared::SPSLookupSymbolsSignature>::handle(
211              ArgData, ArgSize,
212              [](ExecutorAddress ExecutorSessionObj,
213                 std::vector<RemoteSymbolLookup> Lookup) {
214                return ExecutorSessionObj.toPtr<SimpleRemoteEPCServer *>()
215                    ->lookupSymbols(Lookup);
216              })
217       .release();
218 }
219 
220 Expected<tpctypes::DylibHandle>
221 SimpleRemoteEPCServer::loadDylib(const std::string &Path, uint64_t Mode) {
222   std::string ErrMsg;
223   const char *P = Path.empty() ? nullptr : Path.c_str();
224   auto DL = sys::DynamicLibrary::getPermanentLibrary(P, &ErrMsg);
225   if (!DL.isValid())
226     return make_error<StringError>(std::move(ErrMsg), inconvertibleErrorCode());
227   std::lock_guard<std::mutex> Lock(ServerStateMutex);
228   uint64_t Id = Dylibs.size();
229   Dylibs.push_back(std::move(DL));
230   return Id;
231 }
232 
233 Expected<std::vector<std::vector<ExecutorAddress>>>
234 SimpleRemoteEPCServer::lookupSymbols(const std::vector<RemoteSymbolLookup> &L) {
235   std::vector<std::vector<ExecutorAddress>> Result;
236 
237   for (const auto &E : L) {
238     if (E.H >= Dylibs.size())
239       return make_error<StringError>("Unrecognized handle",
240                                      inconvertibleErrorCode());
241     auto &DL = Dylibs[E.H];
242     Result.push_back({});
243 
244     for (const auto &Sym : E.Symbols) {
245 
246       const char *DemangledSymName = Sym.Name.c_str();
247 #ifdef __APPLE__
248       if (*DemangledSymName == '_')
249         ++DemangledSymName;
250 #endif
251 
252       void *Addr = DL.getAddressOfSymbol(DemangledSymName);
253       if (!Addr && Sym.Required)
254         return make_error<StringError>(Twine("Missing definition for ") +
255                                            DemangledSymName,
256                                        inconvertibleErrorCode());
257 
258       Result.back().push_back(ExecutorAddress::fromPtr(Addr));
259     }
260   }
261 
262   return std::move(Result);
263 }
264 
265 shared::WrapperFunctionResult
266 SimpleRemoteEPCServer::doJITDispatch(const void *FnTag, const char *ArgData,
267                                      size_t ArgSize) {
268   uint64_t SeqNo;
269   std::promise<shared::WrapperFunctionResult> ResultP;
270   auto ResultF = ResultP.get_future();
271   {
272     std::lock_guard<std::mutex> Lock(ServerStateMutex);
273     if (RunState != ServerRunning)
274       return shared::WrapperFunctionResult::createOutOfBandError(
275           "jit_dispatch not available (EPC server shut down)");
276 
277     SeqNo = getNextSeqNo();
278     assert(!PendingJITDispatchResults.count(SeqNo) && "SeqNo already in use");
279     PendingJITDispatchResults[SeqNo] = &ResultP;
280   }
281 
282   if (auto Err =
283           T->sendMessage(SimpleRemoteEPCOpcode::CallWrapper, SeqNo,
284                          ExecutorAddress::fromPtr(FnTag), {ArgData, ArgSize}))
285     ReportError(std::move(Err));
286 
287   return ResultF.get();
288 }
289 
290 shared::detail::CWrapperFunctionResult
291 SimpleRemoteEPCServer::jitDispatchEntry(void *DispatchCtx, const void *FnTag,
292                                         const char *ArgData, size_t ArgSize) {
293   return reinterpret_cast<SimpleRemoteEPCServer *>(DispatchCtx)
294       ->doJITDispatch(FnTag, ArgData, ArgSize)
295       .release();
296 }
297 
298 } // end namespace orc
299 } // end namespace llvm
300