1 //===---------- LazyReexports.cpp - Utilities for lazy reexports ----------===//
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/LazyReexports.h"
10 
11 #include "llvm/ADT/Triple.h"
12 #include "llvm/ExecutionEngine/Orc/OrcABISupport.h"
13 
14 #define DEBUG_TYPE "orc"
15 
16 namespace llvm {
17 namespace orc {
18 
anchor()19 void LazyCallThroughManager::NotifyResolvedFunction::anchor() {}
20 
LazyCallThroughManager(ExecutionSession & ES,JITTargetAddress ErrorHandlerAddr,std::unique_ptr<TrampolinePool> TP)21 LazyCallThroughManager::LazyCallThroughManager(
22     ExecutionSession &ES, JITTargetAddress ErrorHandlerAddr,
23     std::unique_ptr<TrampolinePool> TP)
24     : ES(ES), ErrorHandlerAddr(ErrorHandlerAddr), TP(std::move(TP)) {}
25 
getCallThroughTrampoline(JITDylib & SourceJD,SymbolStringPtr SymbolName,std::shared_ptr<NotifyResolvedFunction> NotifyResolved)26 Expected<JITTargetAddress> LazyCallThroughManager::getCallThroughTrampoline(
27     JITDylib &SourceJD, SymbolStringPtr SymbolName,
28     std::shared_ptr<NotifyResolvedFunction> NotifyResolved) {
29   std::lock_guard<std::mutex> Lock(LCTMMutex);
30   auto Trampoline = TP->getTrampoline();
31 
32   if (!Trampoline)
33     return Trampoline.takeError();
34 
35   Reexports[*Trampoline] = std::make_pair(&SourceJD, std::move(SymbolName));
36   Notifiers[*Trampoline] = std::move(NotifyResolved);
37   return *Trampoline;
38 }
39 
40 JITTargetAddress
callThroughToSymbol(JITTargetAddress TrampolineAddr)41 LazyCallThroughManager::callThroughToSymbol(JITTargetAddress TrampolineAddr) {
42   JITDylib *SourceJD = nullptr;
43   SymbolStringPtr SymbolName;
44 
45   {
46     std::lock_guard<std::mutex> Lock(LCTMMutex);
47     auto I = Reexports.find(TrampolineAddr);
48     if (I == Reexports.end())
49       return ErrorHandlerAddr;
50     SourceJD = I->second.first;
51     SymbolName = I->second.second;
52   }
53 
54   auto LookupResult =
55       ES.lookup(JITDylibSearchList({{SourceJD, true}}), SymbolName);
56 
57   if (!LookupResult) {
58     ES.reportError(LookupResult.takeError());
59     return ErrorHandlerAddr;
60   }
61 
62   auto ResolvedAddr = LookupResult->getAddress();
63 
64   std::shared_ptr<NotifyResolvedFunction> NotifyResolved = nullptr;
65   {
66     std::lock_guard<std::mutex> Lock(LCTMMutex);
67     auto I = Notifiers.find(TrampolineAddr);
68     if (I != Notifiers.end()) {
69       NotifyResolved = I->second;
70       Notifiers.erase(I);
71     }
72   }
73 
74   if (NotifyResolved) {
75     if (auto Err = (*NotifyResolved)(*SourceJD, SymbolName, ResolvedAddr)) {
76       ES.reportError(std::move(Err));
77       return ErrorHandlerAddr;
78     }
79   }
80 
81   return ResolvedAddr;
82 }
83 
84 Expected<std::unique_ptr<LazyCallThroughManager>>
createLocalLazyCallThroughManager(const Triple & T,ExecutionSession & ES,JITTargetAddress ErrorHandlerAddr)85 createLocalLazyCallThroughManager(const Triple &T, ExecutionSession &ES,
86                                   JITTargetAddress ErrorHandlerAddr) {
87   switch (T.getArch()) {
88   default:
89     return make_error<StringError>(
90         std::string("No callback manager available for ") + T.str(),
91         inconvertibleErrorCode());
92 
93   case Triple::aarch64:
94     return LocalLazyCallThroughManager::Create<OrcAArch64>(ES,
95                                                            ErrorHandlerAddr);
96 
97   case Triple::x86:
98     return LocalLazyCallThroughManager::Create<OrcI386>(ES, ErrorHandlerAddr);
99 
100   case Triple::mips:
101     return LocalLazyCallThroughManager::Create<OrcMips32Be>(ES,
102                                                             ErrorHandlerAddr);
103 
104   case Triple::mipsel:
105     return LocalLazyCallThroughManager::Create<OrcMips32Le>(ES,
106                                                             ErrorHandlerAddr);
107 
108   case Triple::mips64:
109   case Triple::mips64el:
110     return LocalLazyCallThroughManager::Create<OrcMips64>(ES, ErrorHandlerAddr);
111 
112   case Triple::x86_64:
113     if (T.getOS() == Triple::OSType::Win32)
114       return LocalLazyCallThroughManager::Create<OrcX86_64_Win32>(
115           ES, ErrorHandlerAddr);
116     else
117       return LocalLazyCallThroughManager::Create<OrcX86_64_SysV>(
118           ES, ErrorHandlerAddr);
119   }
120 }
121 
LazyReexportsMaterializationUnit(LazyCallThroughManager & LCTManager,IndirectStubsManager & ISManager,JITDylib & SourceJD,SymbolAliasMap CallableAliases,VModuleKey K)122 LazyReexportsMaterializationUnit::LazyReexportsMaterializationUnit(
123     LazyCallThroughManager &LCTManager, IndirectStubsManager &ISManager,
124     JITDylib &SourceJD, SymbolAliasMap CallableAliases, VModuleKey K)
125     : MaterializationUnit(extractFlags(CallableAliases), std::move(K)),
126       LCTManager(LCTManager), ISManager(ISManager), SourceJD(SourceJD),
127       CallableAliases(std::move(CallableAliases)),
128       NotifyResolved(LazyCallThroughManager::createNotifyResolvedFunction(
129           [&ISManager](JITDylib &JD, const SymbolStringPtr &SymbolName,
130                        JITTargetAddress ResolvedAddr) {
131             return ISManager.updatePointer(*SymbolName, ResolvedAddr);
132           })) {}
133 
getName() const134 StringRef LazyReexportsMaterializationUnit::getName() const {
135   return "<Lazy Reexports>";
136 }
137 
materialize(MaterializationResponsibility R)138 void LazyReexportsMaterializationUnit::materialize(
139     MaterializationResponsibility R) {
140   auto RequestedSymbols = R.getRequestedSymbols();
141 
142   SymbolAliasMap RequestedAliases;
143   for (auto &RequestedSymbol : RequestedSymbols) {
144     auto I = CallableAliases.find(RequestedSymbol);
145     assert(I != CallableAliases.end() && "Symbol not found in alias map?");
146     RequestedAliases[I->first] = std::move(I->second);
147     CallableAliases.erase(I);
148   }
149 
150   if (!CallableAliases.empty())
151     R.replace(lazyReexports(LCTManager, ISManager, SourceJD,
152                             std::move(CallableAliases)));
153 
154   IndirectStubsManager::StubInitsMap StubInits;
155   for (auto &Alias : RequestedAliases) {
156 
157     auto CallThroughTrampoline = LCTManager.getCallThroughTrampoline(
158         SourceJD, Alias.second.Aliasee, NotifyResolved);
159 
160     if (!CallThroughTrampoline) {
161       SourceJD.getExecutionSession().reportError(
162           CallThroughTrampoline.takeError());
163       R.failMaterialization();
164       return;
165     }
166 
167     StubInits[*Alias.first] =
168         std::make_pair(*CallThroughTrampoline, Alias.second.AliasFlags);
169   }
170 
171   if (auto Err = ISManager.createStubs(StubInits)) {
172     SourceJD.getExecutionSession().reportError(std::move(Err));
173     R.failMaterialization();
174     return;
175   }
176 
177   SymbolMap Stubs;
178   for (auto &Alias : RequestedAliases)
179     Stubs[Alias.first] = ISManager.findStub(*Alias.first, false);
180 
181   R.notifyResolved(Stubs);
182   R.notifyEmitted();
183 }
184 
discard(const JITDylib & JD,const SymbolStringPtr & Name)185 void LazyReexportsMaterializationUnit::discard(const JITDylib &JD,
186                                                const SymbolStringPtr &Name) {
187   assert(CallableAliases.count(Name) &&
188          "Symbol not covered by this MaterializationUnit");
189   CallableAliases.erase(Name);
190 }
191 
192 SymbolFlagsMap
extractFlags(const SymbolAliasMap & Aliases)193 LazyReexportsMaterializationUnit::extractFlags(const SymbolAliasMap &Aliases) {
194   SymbolFlagsMap SymbolFlags;
195   for (auto &KV : Aliases) {
196     assert(KV.second.AliasFlags.isCallable() &&
197            "Lazy re-exports must be callable symbols");
198     SymbolFlags[KV.first] = KV.second.AliasFlags;
199   }
200   return SymbolFlags;
201 }
202 
203 } // End namespace orc.
204 } // End namespace llvm.
205