3 files changed, 344 insertions, 2 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt b/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
index f83e002c758..ee64990dfb4 100644
--- a/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
+++ b/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_llvm_library(LLVMOrcJIT
+  Core.cpp
   ExecutionUtils.cpp
   IndirectionUtils.cpp
   NullResolver.cpp
diff --git a/llvm/lib/ExecutionEngine/Orc/Core.cpp b/llvm/lib/ExecutionEngine/Orc/Core.cpp
new file mode 100644
index 00000000000..a56edc4114a
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/Orc/Core.cpp
@@ -0,0 +1,322 @@
+//===--------- Core.cpp - Core ORC APIs (SymbolSource, VSO, etc.) ---------===//
+//
+//                     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/Core.h"
+#include "llvm/ExecutionEngine/Orc/OrcError.h"
+
+namespace llvm {
+namespace orc {
+
+void SymbolSource::anchor() {}
+
+AsynchronousSymbolQuery::AsynchronousSymbolQuery(
+                                  const SymbolNameSet &Symbols,
+                                  SymbolsResolvedCallback NotifySymbolsResolved,
+                                  SymbolsReadyCallback NotifySymbolsReady)
+    : NotifySymbolsResolved(std::move(NotifySymbolsResolved)),
+      NotifySymbolsReady(std::move(NotifySymbolsReady)) {
+  assert(NotifySymbolsResolved && "Symbols resolved callback must be set");
+  assert(NotifySymbolsReady && "Symbols ready callback must be set");
+  OutstandingResolutions = OutstandingFinalizations = Symbols.size();
+}
+
+void AsynchronousSymbolQuery::setFailed(Error Err) {
+  OutstandingResolutions = OutstandingFinalizations = 0;
+  if (NotifySymbolsResolved)
+    NotifySymbolsResolved(std::move(Err));
+  else
+    NotifySymbolsReady(std::move(Err));
+}
+
+void AsynchronousSymbolQuery::setDefinition(SymbolStringPtr Name,
+                                            JITSymbol Sym) {
+  // If OutstandingResolutions is zero we must have errored out already. Just
+  // ignore this.
+  if (OutstandingResolutions == 0)
+    return;
+
+  assert(!Symbols.count(Name) &&
+         "Symbol has already been assigned an address");
+  Symbols.insert(std::make_pair(std::move(Name), std::move(Sym)));
+  --OutstandingResolutions;
+  if (OutstandingResolutions == 0) {
+    NotifySymbolsResolved(std::move(Symbols));
+    // Null out NotifySymbolsResolved to indicate that we've already called it.
+    NotifySymbolsResolved = {};
+  }
+}
+
+void AsynchronousSymbolQuery::notifySymbolFinalized() {
+  // If OutstandingFinalizations is zero we must have errored out already. Just
+  // ignore this.
+  if (OutstandingFinalizations == 0)
+    return;
+
+  assert(OutstandingFinalizations > 0 && "All symbols already finalized");
+  --OutstandingFinalizations;
+  if (OutstandingFinalizations == 0)
+    NotifySymbolsReady(Error::success());
+}
+
+VSO::MaterializationInfo::MaterializationInfo(JITSymbolFlags Flags,
+                                              AsynchronousSymbolQuery &Query)
+  : Flags(std::move(Flags)), PendingResolution({ &Query }) {}
+
+JITSymbolFlags VSO::MaterializationInfo::getFlags() const {
+  return Flags;
+}
+
+JITTargetAddress VSO::MaterializationInfo::getAddress() const {
+  return Address;
+}
+
+void VSO::MaterializationInfo::query(SymbolStringPtr Name,
+                                     AsynchronousSymbolQuery &Query) {
+  if (Address != 0) {
+    Query.setDefinition(Name, JITSymbol(Address, Flags));
+    PendingFinalization.push_back(&Query);
+  } else
+    PendingResolution.push_back(&Query);
+}
+
+void VSO::MaterializationInfo::resolve(SymbolStringPtr Name, JITSymbol Sym) {
+  // FIXME: Sanity check flags?
+  Flags = Sym.getFlags();
+  Address = cantFail(Sym.getAddress());
+  for (auto *Query : PendingResolution) {
+    Query->setDefinition(Name, std::move(Sym));
+    PendingFinalization.push_back(Query);
+  }
+  PendingResolution = {};
+}
+
+void VSO::MaterializationInfo::finalize() {
+  for (auto *Query : PendingFinalization)
+    Query->notifySymbolFinalized();
+  PendingFinalization = {};
+}
+
+VSO::SymbolTableEntry::SymbolTableEntry(JITSymbolFlags Flags, SymbolSource &Source)
+  : Flags(JITSymbolFlags::FlagNames(Flags | JITSymbolFlags::NotMaterialized)),
+    Source(&Source) {
+  // FIXME: Assert flag sanity.
+}
+
+VSO::SymbolTableEntry::SymbolTableEntry(JITSymbol Sym)
+  : Flags(Sym.getFlags()), Address(cantFail(Sym.getAddress())) {
+  // FIXME: Assert flag sanity.
+}
+
+VSO::SymbolTableEntry::SymbolTableEntry(SymbolTableEntry &&Other)
+  : Flags(Other.Flags), Address(0) {
+  if (Flags.isMaterializing())
+    MatInfo = std::move(Other.MatInfo);
+  else
+    Source = Other.Source;
+}
+
+VSO::SymbolTableEntry::~SymbolTableEntry() {
+  assert(!Flags.isMaterializing() &&
+         "Symbol table entry destroyed while symbol was being materialized");
+}
+
+JITSymbolFlags VSO::SymbolTableEntry::getFlags() const { return Flags; }
+
+void VSO::SymbolTableEntry::replaceWithSource(VSO &V,
+                                              SymbolStringPtr Name,
+                                              JITSymbolFlags Flags,
+                                              SymbolSource &NewSource) {
+  assert(!this->Flags.isMaterializing() &&
+         "Attempted to replace symbol with lazy definition during "
+         "materialization");
+  if (!this->Flags.isMaterialized())
+    Source->discard(V, Name);
+  this->Flags = Flags;
+  this->Source = &NewSource;
+}
+
+SymbolSource*
+VSO::SymbolTableEntry::query(SymbolStringPtr Name,
+                             AsynchronousSymbolQuery &Query) {
+  if (Flags.isMaterializing()) {
+    MatInfo->query(std::move(Name), Query);
+    return nullptr;
+  } else if (Flags.isMaterialized()) {
+    Query.setDefinition(std::move(Name), JITSymbol(Address, Flags));
+    Query.notifySymbolFinalized();
+    return nullptr;
+  }
+  SymbolSource *S = Source;
+  new (&MatInfo) std::unique_ptr<MaterializationInfo>(
+    llvm::make_unique<MaterializationInfo>(Flags, Query));
+  Flags |= JITSymbolFlags::Materializing;
+  return S;
+}
+
+void VSO::SymbolTableEntry::resolve(VSO &V, SymbolStringPtr Name,
+                                      JITSymbol Sym) {
+  if (Flags.isMaterializing())
+    MatInfo->resolve(std::move(Name), std::move(Sym));
+  else {
+    // If there's a layer for this symbol.
+    if (!Flags.isMaterialized())
+      Source->discard(V, Name);
+
+    // FIXME: Should we assert flag state here (flags must match except for
+    //        materialization state, overrides must be legal) or in the caller
+    //        in VSO?
+    Flags = Sym.getFlags();
+    Address = cantFail(Sym.getAddress());
+  }
+}
+
+void VSO::SymbolTableEntry::finalize() {
+  if (Flags.isMaterializing()) {
+    auto TmpMatInfo = std::move(MatInfo);
+    MatInfo.std::unique_ptr<MaterializationInfo>::~unique_ptr();
+    // FIXME: Assert flag sanity?
+    Flags = TmpMatInfo->getFlags();
+    Address = TmpMatInfo->getAddress();
+    TmpMatInfo->finalize();
+  }
+  assert(Flags.isMaterialized() && "Trying to finalize not-emitted symbol");
+}
+
+VSO::RelativeLinkageStrength
+VSO::compareLinkage(Optional<JITSymbolFlags> Old, JITSymbolFlags New) {
+  if (Old == None)
+    return llvm::orc::VSO::NewDefinitionIsStronger;
+
+  if (Old->isStrongDefinition()) {
+    if (New.isStrongDefinition())
+      return llvm::orc::VSO::DuplicateDefinition;
+    else
+      return llvm::orc::VSO::ExistingDefinitionIsStronger;
+  } else {
+    if (New.isStrongDefinition())
+      return llvm::orc::VSO::NewDefinitionIsStronger;
+    else
+      return llvm::orc::VSO::ExistingDefinitionIsStronger;
+  }
+}
+
+VSO::RelativeLinkageStrength
+VSO::compareLinkage(SymbolStringPtr Name, JITSymbolFlags NewFlags) const {
+  auto I = Symbols.find(Name);
+  return compareLinkage(I == Symbols.end()
+                        ? None
+                        : Optional<JITSymbolFlags>(I->second.getFlags()),
+                        NewFlags);
+}
+
+Error VSO::define(SymbolMap NewSymbols) {
+  Error Err = Error::success();
+  for (auto &KV : NewSymbols) {
+    auto I = Symbols.find(KV.first);
+    auto LinkageResult =
+      compareLinkage(I == Symbols.end()
+                     ? None
+                     : Optional<JITSymbolFlags>(I->second.getFlags()),
+                     KV.second.getFlags());
+
+    // Silently discard weaker definitions.
+    if (LinkageResult == ExistingDefinitionIsStronger)
+      continue;
+
+    // Report duplicate definition errors.
+    if (LinkageResult == DuplicateDefinition) {
+      Err = joinErrors(std::move(Err),
+                       make_error<orc::DuplicateDefinition>(*KV.first));
+      continue;
+    }
+
+    if (I != Symbols.end()) {
+      I->second.resolve(*this, KV.first, std::move(KV.second));
+      I->second.finalize();
+    } else
+      Symbols.insert(std::make_pair(KV.first, std::move(KV.second)));
+  }
+  return Err;
+}
+
+Error VSO::defineLazy(const SymbolFlagsMap &NewSymbols, SymbolSource &Source) {
+  Error Err = Error::success();
+  for (auto &KV : NewSymbols) {
+    auto I = Symbols.find(KV.first);
+
+    auto LinkageResult =
+      compareLinkage(I == Symbols.end()
+                     ? None
+                     : Optional<JITSymbolFlags>(I->second.getFlags()),
+                     KV.second);
+
+    // Discard weaker definitions.
+    if (LinkageResult == ExistingDefinitionIsStronger)
+      Source.discard(*this, KV.first);
+
+    // Report duplicate definition errors.
+    if (LinkageResult == DuplicateDefinition) {
+      Err = joinErrors(std::move(Err),
+                       make_error<orc::DuplicateDefinition>(*KV.first));
+      continue;
+    }
+
+    if (I != Symbols.end())
+      I->second.replaceWithSource(*this, KV.first, KV.second, Source);
+    else
+      Symbols.emplace(std::make_pair(KV.first, 
+                                    SymbolTableEntry(KV.second, Source)));
+  }
+  return Err;
+}
+
+void VSO::resolve(SymbolMap SymbolValues) {
+  for (auto &KV : SymbolValues) {
+    auto I = Symbols.find(KV.first);
+    assert(I != Symbols.end() && "Resolving symbol not present in this dylib");
+    I->second.resolve(*this, KV.first, std::move(KV.second));
+  }
+}
+
+void VSO::finalize(SymbolNameSet SymbolsToFinalize) {
+  for (auto &S : SymbolsToFinalize) {
+    auto I = Symbols.find(S);
+    assert(I != Symbols.end() && "Finalizing symbol not present in this dylib");
+    I->second.finalize();
+  }
+}
+
+VSO::LookupResult VSO::lookup(AsynchronousSymbolQuery &Query,
+                              SymbolNameSet Names) {
+  SourceWorkMap MaterializationWork;
+
+  for (SymbolNameSet::iterator I = Names.begin(), E = Names.end(); I != E;) {
+    auto Tmp = I;
+    ++I;
+    auto SymI = Symbols.find(*Tmp);
+
+    // If the symbol isn't in this dylib then just continue.
+    // If it is, erase it from Names and proceed.
+    if (SymI == Symbols.end())
+      continue;
+    else
+      Names.erase(Tmp);
+
+    // Forward the query to the given SymbolTableEntry, and if it return a
+    // layer to perform materialization with, add that to the
+    // MaterializationWork map.
+    if (auto *Source = SymI->second.query(SymI->first, Query))
+      MaterializationWork[Source].insert(SymI->first);
+  }
+
+  return { std::move(MaterializationWork), std::move(Names) };
+}
+
+} // End namespace orc.
+} // End namespace llvm.
diff --git a/llvm/lib/ExecutionEngine/Orc/OrcError.cpp b/llvm/lib/ExecutionEngine/Orc/OrcError.cpp
index c218cb9a523..f0bfed8ddb8 100644
--- a/llvm/lib/ExecutionEngine/Orc/OrcError.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/OrcError.cpp
@@ -29,6 +29,10 @@ public:
 
   std::string message(int condition) const override {
     switch (static_cast<OrcErrorCode>(condition)) {
+    case OrcErrorCode::DuplicateDefinition:
+      return "Duplicate symbol definition";
+    case OrcErrorCode::JITSymbolNotFound:
+      return "JIT symbol not found";
     case OrcErrorCode::RemoteAllocatorDoesNotExist:
       return "Remote allocator does not exist";
     case OrcErrorCode::RemoteAllocatorIdAlreadyInUse:
@@ -45,8 +49,6 @@ public:
       return "Could not negotiate RPC function";
     case OrcErrorCode::RPCResponseAbandoned:
       return "RPC response abandoned";
-    case OrcErrorCode::JITSymbolNotFound:
-      return "JIT symbol not found";
     case OrcErrorCode::UnexpectedRPCCall:
       return "Unexpected RPC call";
     case OrcErrorCode::UnexpectedRPCResponse:
@@ -67,6 +69,7 @@ static ManagedStatic<OrcErrorCategory> OrcErrCat;
 namespace llvm {
 namespace orc {
 
+char DuplicateDefinition::ID = 0;
 char JITSymbolNotFound::ID = 0;
 
 std::error_code orcError(OrcErrorCode ErrCode) {
@@ -74,6 +77,22 @@ std::error_code orcError(OrcErrorCode ErrCode) {
   return std::error_code(static_cast<UT>(ErrCode), *OrcErrCat);
 }
 
+
+DuplicateDefinition::DuplicateDefinition(std::string SymbolName)
+  : SymbolName(std::move(SymbolName)) {}
+
+std::error_code DuplicateDefinition::convertToErrorCode() const {
+  return orcError(OrcErrorCode::DuplicateDefinition);
+}
+
+void DuplicateDefinition::log(raw_ostream &OS) const {
+  OS << "Duplicate definition of symbol '" << SymbolName << "'";
+}
+
+const std::string &DuplicateDefinition::getSymbolName() const {
+  return SymbolName;
+}
+
 JITSymbolNotFound::JITSymbolNotFound(std::string SymbolName)
   : SymbolName(std::move(SymbolName)) {}