[ORC] Add a "lazy call-through" utility based on the same underlying trampoline
implementation as lazy compile callbacks, and a "lazy re-exports" utility that
builds lazy call-throughs.
Lazy call-throughs are similar to lazy compile callbacks (and are based on the
same underlying state saving/restoring trampolines) but resolve their targets
by performing a standard ORC lookup rather than invoking a user supplied
compiler callback. This allows them to inherit the thread-safety of ORC lookups
while blocking only the calling thread (whereas compile callbacks also block one
compile thread).
Lazy re-exports provide a simple way of building lazy call-throughs. Unlike a
regular re-export, a lazy re-export generates a new address (a stub entry point)
that will act like the re-exported symbol when called. The first call via a
lazy re-export will trigger compilation of the re-exported symbol before calling
through to it.
llvm-svn: 343061
diff --git a/llvm/lib/ExecutionEngine/Orc/LazyReexports.cpp b/llvm/lib/ExecutionEngine/Orc/LazyReexports.cpp
new file mode 100644
index 0000000..c327005
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/Orc/LazyReexports.cpp
@@ -0,0 +1,204 @@
+//===---------- LazyReexports.cpp - Utilities for lazy reexports ----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/Orc/LazyReexports.h"
+
+#include "llvm/ADT/Triple.h"
+#include "llvm/ExecutionEngine/Orc/OrcABISupport.h"
+
+#define DEBUG_TYPE "orc"
+
+namespace llvm {
+namespace orc {
+
+void LazyCallThroughManager::NotifyResolvedFunction::anchor() {}
+
+LazyCallThroughManager::LazyCallThroughManager(
+ ExecutionSession &ES, JITTargetAddress ErrorHandlerAddr,
+ std::unique_ptr<TrampolinePool> TP)
+ : ES(ES), ErrorHandlerAddr(ErrorHandlerAddr), TP(std::move(TP)) {}
+
+Expected<JITTargetAddress> LazyCallThroughManager::getCallThroughTrampoline(
+ JITDylib &SourceJD, SymbolStringPtr SymbolName,
+ std::shared_ptr<NotifyResolvedFunction> NotifyResolved) {
+ std::lock_guard<std::mutex> Lock(LCTMMutex);
+ auto Trampoline = TP->getTrampoline();
+
+ if (!Trampoline)
+ return Trampoline.takeError();
+
+ Reexports[*Trampoline] = std::make_pair(&SourceJD, std::move(SymbolName));
+ Notifiers[*Trampoline] = std::move(NotifyResolved);
+ return *Trampoline;
+}
+
+JITTargetAddress
+LazyCallThroughManager::callThroughToSymbol(JITTargetAddress TrampolineAddr) {
+ JITDylib *SourceJD = nullptr;
+ SymbolStringPtr SymbolName;
+
+ {
+ std::lock_guard<std::mutex> Lock(LCTMMutex);
+ auto I = Reexports.find(TrampolineAddr);
+ if (I == Reexports.end())
+ return ErrorHandlerAddr;
+ SourceJD = I->second.first;
+ SymbolName = I->second.second;
+ }
+
+ auto LookupResult =
+ ES.lookup({SourceJD}, {SymbolName}, NoDependenciesToRegister);
+
+ if (!LookupResult) {
+ ES.reportError(LookupResult.takeError());
+ return ErrorHandlerAddr;
+ }
+
+ assert(LookupResult->size() == 1 && "Unexpected number of results");
+ assert(LookupResult->count(SymbolName) && "Unexpected result");
+
+ auto ResolvedAddr = LookupResult->begin()->second.getAddress();
+
+ std::shared_ptr<NotifyResolvedFunction> NotifyResolved = nullptr;
+ {
+ std::lock_guard<std::mutex> Lock(LCTMMutex);
+ auto I = Notifiers.find(TrampolineAddr);
+ if (I != Notifiers.end()) {
+ NotifyResolved = I->second;
+ Notifiers.erase(I);
+ }
+ }
+
+ if (NotifyResolved) {
+ if (auto Err = (*NotifyResolved)(*SourceJD, SymbolName, ResolvedAddr)) {
+ ES.reportError(std::move(Err));
+ return ErrorHandlerAddr;
+ }
+ }
+
+ return ResolvedAddr;
+}
+
+Expected<std::unique_ptr<LazyCallThroughManager>>
+createLocalLazyCallThroughManager(const Triple &T, ExecutionSession &ES,
+ JITTargetAddress ErrorHandlerAddr) {
+ switch (T.getArch()) {
+ default:
+ return make_error<StringError>(
+ std::string("No callback manager available for ") + T.str(),
+ inconvertibleErrorCode());
+
+ case Triple::aarch64:
+ return LocalLazyCallThroughManager::Create<OrcAArch64>(ES,
+ ErrorHandlerAddr);
+
+ case Triple::x86:
+ return LocalLazyCallThroughManager::Create<OrcI386>(ES, ErrorHandlerAddr);
+
+ case Triple::mips:
+ return LocalLazyCallThroughManager::Create<OrcMips32Be>(ES,
+ ErrorHandlerAddr);
+
+ case Triple::mipsel:
+ return LocalLazyCallThroughManager::Create<OrcMips32Le>(ES,
+ ErrorHandlerAddr);
+
+ case Triple::mips64:
+ case Triple::mips64el:
+ return LocalLazyCallThroughManager::Create<OrcMips64>(ES, ErrorHandlerAddr);
+
+ case Triple::x86_64:
+ if (T.getOS() == Triple::OSType::Win32)
+ return LocalLazyCallThroughManager::Create<OrcX86_64_Win32>(
+ ES, ErrorHandlerAddr);
+ else
+ return LocalLazyCallThroughManager::Create<OrcX86_64_SysV>(
+ ES, ErrorHandlerAddr);
+ }
+}
+
+LazyReexportsMaterializationUnit::LazyReexportsMaterializationUnit(
+ LazyCallThroughManager &LCTManager, IndirectStubsManager &ISManager,
+ JITDylib &SourceJD, SymbolAliasMap CallableAliases)
+ : MaterializationUnit(extractFlags(CallableAliases)),
+ LCTManager(LCTManager), ISManager(ISManager), SourceJD(SourceJD),
+ CallableAliases(std::move(CallableAliases)),
+ NotifyResolved(LazyCallThroughManager::createNotifyResolvedFunction(
+ [&ISManager](JITDylib &JD, const SymbolStringPtr &SymbolName,
+ JITTargetAddress ResolvedAddr) {
+ return ISManager.updatePointer(*SymbolName, ResolvedAddr);
+ })) {}
+
+void LazyReexportsMaterializationUnit::materialize(
+ MaterializationResponsibility R) {
+ auto RequestedSymbols = R.getRequestedSymbols();
+
+ SymbolAliasMap RequestedAliases;
+ for (auto &RequestedSymbol : RequestedSymbols) {
+ auto I = CallableAliases.find(RequestedSymbol);
+ assert(I != CallableAliases.end() && "Symbol not found in alias map?");
+ RequestedAliases[I->first] = std::move(I->second);
+ CallableAliases.erase(I);
+ }
+
+ if (!CallableAliases.empty())
+ R.replace(lazyReexports(LCTManager, ISManager, SourceJD,
+ std::move(CallableAliases)));
+
+ IndirectStubsManager::StubInitsMap StubInits;
+ for (auto &Alias : RequestedAliases) {
+
+ auto CallThroughTrampoline = LCTManager.getCallThroughTrampoline(
+ SourceJD, Alias.second.Aliasee, NotifyResolved);
+
+ if (!CallThroughTrampoline) {
+ SourceJD.getExecutionSession().reportError(
+ CallThroughTrampoline.takeError());
+ R.failMaterialization();
+ return;
+ }
+
+ StubInits[*Alias.first] =
+ std::make_pair(*CallThroughTrampoline, Alias.second.AliasFlags);
+ }
+
+ if (auto Err = ISManager.createStubs(StubInits)) {
+ SourceJD.getExecutionSession().reportError(std::move(Err));
+ R.failMaterialization();
+ return;
+ }
+
+ SymbolMap Stubs;
+ for (auto &Alias : RequestedAliases)
+ Stubs[Alias.first] = ISManager.findStub(*Alias.first, false);
+
+ R.resolve(Stubs);
+ R.emit();
+}
+
+void LazyReexportsMaterializationUnit::discard(const JITDylib &JD,
+ SymbolStringPtr Name) {
+ assert(CallableAliases.count(Name) &&
+ "Symbol not covered by this MaterializationUnit");
+ CallableAliases.erase(Name);
+}
+
+SymbolFlagsMap
+LazyReexportsMaterializationUnit::extractFlags(const SymbolAliasMap &Aliases) {
+ SymbolFlagsMap SymbolFlags;
+ for (auto &KV : Aliases) {
+ assert(KV.second.AliasFlags.isCallable() &&
+ "Lazy re-exports must be callable symbols");
+ SymbolFlags[KV.first] = KV.second.AliasFlags;
+ }
+ return SymbolFlags;
+}
+
+} // End namespace orc.
+} // End namespace llvm.