[ORC] Add support for emulated TLS to ORCv2.

This commit adds a ManglingOptions struct to IRMaterializationUnit, and replaces
IRCompileLayer::CompileFunction with a new IRCompileLayer::IRCompiler class. The
ManglingOptions struct defines the emulated-TLS state (via a bool member,
EmulatedTLS, which is true if emulated-TLS is enabled and false otherwise). The
IRCompileLayer::IRCompiler class wraps an IRCompiler (the same way that the
CompileFunction typedef used to), but adds a method to return the
IRCompileLayer::ManglingOptions that the compiler will use.

These changes allow us to correctly determine the symbols that will be produced
when a thread local global variable defined at the IR level is compiled with or
without emulated TLS. This is required for ORCv2, where MaterializationUnits
must declare their interface up-front.

Most ORCv2 clients should not require any changes. Clients writing custom IR
compilers will need to wrap their compiler in an IRCompileLayer::IRCompiler,
rather than an IRCompileLayer::CompileFunction, however this should be a
straightforward change (see modifications to CompileUtils.* in this patch for an
example).

(cherry picked from commit ce2207abaf9a925b35f15ef92aaff6b301ba6d22)

6 files changed, 96 insertions, 50 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/CompileOnDemandLayer.cpp b/llvm/lib/ExecutionEngine/Orc/CompileOnDemandLayer.cpp
index f26835ff8a0..9c504da611e 100644
--- a/llvm/lib/ExecutionEngine/Orc/CompileOnDemandLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/CompileOnDemandLayer.cpp
@@ -67,9 +67,11 @@ namespace orc {
 
 class PartitioningIRMaterializationUnit : public IRMaterializationUnit {
 public:
-  PartitioningIRMaterializationUnit(ExecutionSession &ES, ThreadSafeModule TSM,
-                                    VModuleKey K, CompileOnDemandLayer &Parent)
-      : IRMaterializationUnit(ES, std::move(TSM), std::move(K)),
+  PartitioningIRMaterializationUnit(ExecutionSession &ES,
+                                    const ManglingOptions &MO,
+                                    ThreadSafeModule TSM, VModuleKey K,
+                                    CompileOnDemandLayer &Parent)
+      : IRMaterializationUnit(ES, MO, std::move(TSM), std::move(K)),
         Parent(Parent) {}
 
   PartitioningIRMaterializationUnit(
@@ -111,7 +113,8 @@ CompileOnDemandLayer::compileWholeModule(GlobalValueSet Requested) {
 CompileOnDemandLayer::CompileOnDemandLayer(
     ExecutionSession &ES, IRLayer &BaseLayer, LazyCallThroughManager &LCTMgr,
     IndirectStubsManagerBuilder BuildIndirectStubsManager)
-    : IRLayer(ES), BaseLayer(BaseLayer), LCTMgr(LCTMgr),
+    : IRLayer(ES, BaseLayer.getManglingOptions()), BaseLayer(BaseLayer),
+      LCTMgr(LCTMgr),
       BuildIndirectStubsManager(std::move(BuildIndirectStubsManager)) {}
 
 void CompileOnDemandLayer::setPartitionFunction(PartitionFunction Partition) {
@@ -136,27 +139,23 @@ void CompileOnDemandLayer::emit(MaterializationResponsibility R,
   TSM.withModuleDo([&](Module &M) {
     // First, do some cleanup on the module:
     cleanUpModule(M);
-
-    MangleAndInterner Mangle(ES, M.getDataLayout());
-    for (auto &GV : M.global_values()) {
-      if (GV.isDeclaration() || GV.hasLocalLinkage() ||
-          GV.hasAppendingLinkage())
-        continue;
-
-      auto Name = Mangle(GV.getName());
-      auto Flags = JITSymbolFlags::fromGlobalValue(GV);
-      if (Flags.isCallable())
-        Callables[Name] = SymbolAliasMapEntry(Name, Flags);
-      else
-        NonCallables[Name] = SymbolAliasMapEntry(Name, Flags);
-    }
   });
 
+  for (auto &KV : R.getSymbols()) {
+    auto &Name = KV.first;
+    auto &Flags = KV.second;
+    if (Flags.isCallable())
+      Callables[Name] = SymbolAliasMapEntry(Name, Flags);
+    else
+      NonCallables[Name] = SymbolAliasMapEntry(Name, Flags);
+  }
+
   // Create a partitioning materialization unit and lodge it with the
   // implementation dylib.
   if (auto Err = PDR.getImplDylib().define(
           std::make_unique<PartitioningIRMaterializationUnit>(
-              ES, std::move(TSM), R.getVModuleKey(), *this))) {
+              ES, *getManglingOptions(), std::move(TSM), R.getVModuleKey(),
+              *this))) {
     ES.reportError(std::move(Err));
     R.failMaterialization();
     return;
@@ -316,7 +315,7 @@ void CompileOnDemandLayer::emitPartition(
   }
 
   R.replace(std::make_unique<PartitioningIRMaterializationUnit>(
-      ES, std::move(TSM), R.getVModuleKey(), *this));
+      ES, *getManglingOptions(), std::move(TSM), R.getVModuleKey(), *this));
   BaseLayer.emit(std::move(R), std::move(*ExtractedTSM));
 }
 
diff --git a/llvm/lib/ExecutionEngine/Orc/CompileUtils.cpp b/llvm/lib/ExecutionEngine/Orc/CompileUtils.cpp
index f5671d90420..8d2c2d9c129 100644
--- a/llvm/lib/ExecutionEngine/Orc/CompileUtils.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/CompileUtils.cpp
@@ -24,8 +24,17 @@
 namespace llvm {
 namespace orc {
 
+IRMaterializationUnit::ManglingOptions
+irManglingOptionsFromTargetOptions(const TargetOptions &Opts) {
+  IRMaterializationUnit::ManglingOptions MO;
+
+  MO.EmulatedTLS = Opts.EmulatedTLS;
+
+  return MO;
+}
+
 /// Compile a Module to an ObjectFile.
-SimpleCompiler::CompileResult SimpleCompiler::operator()(Module &M) {
+Expected<SimpleCompiler::CompileResult> SimpleCompiler::operator()(Module &M) {
   CompileResult CachedObject = tryToLoadFromObjectCache(M);
   if (CachedObject)
     return CachedObject;
@@ -38,7 +47,8 @@ SimpleCompiler::CompileResult SimpleCompiler::operator()(Module &M) {
     legacy::PassManager PM;
     MCContext *Ctx;
     if (TM.addPassesToEmitMC(PM, Ctx, ObjStream))
-      llvm_unreachable("Target does not support MC emission.");
+      return make_error<StringError>("Target does not support MC emission",
+                                     inconvertibleErrorCode());
     PM.run(M);
   }
 
@@ -47,14 +57,11 @@ SimpleCompiler::CompileResult SimpleCompiler::operator()(Module &M) {
 
   auto Obj = object::ObjectFile::createObjectFile(ObjBuffer->getMemBufferRef());
 
-  if (Obj) {
-    notifyObjectCompiled(M, *ObjBuffer);
-    return std::move(ObjBuffer);
-  }
+  if (!Obj)
+    return Obj.takeError();
 
-  // TODO: Actually report errors helpfully.
-  consumeError(Obj.takeError());
-  return nullptr;
+  notifyObjectCompiled(M, *ObjBuffer);
+  return std::move(ObjBuffer);
 }
 
 SimpleCompiler::CompileResult
@@ -73,9 +80,11 @@ void SimpleCompiler::notifyObjectCompiled(const Module &M,
 
 ConcurrentIRCompiler::ConcurrentIRCompiler(JITTargetMachineBuilder JTMB,
                                            ObjectCache *ObjCache)
-    : JTMB(std::move(JTMB)), ObjCache(ObjCache) {}
+    : IRCompiler(irManglingOptionsFromTargetOptions(JTMB.getOptions())),
+      JTMB(std::move(JTMB)), ObjCache(ObjCache) {}
 
-std::unique_ptr<MemoryBuffer> ConcurrentIRCompiler::operator()(Module &M) {
+Expected<std::unique_ptr<MemoryBuffer>>
+ConcurrentIRCompiler::operator()(Module &M) {
   auto TM = cantFail(JTMB.createTargetMachine());
   SimpleCompiler C(*TM, ObjCache);
   return C(M);
diff --git a/llvm/lib/ExecutionEngine/Orc/IRCompileLayer.cpp b/llvm/lib/ExecutionEngine/Orc/IRCompileLayer.cpp
index d311f34179c..023940dc829 100644
--- a/llvm/lib/ExecutionEngine/Orc/IRCompileLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/IRCompileLayer.cpp
@@ -11,9 +11,14 @@
 namespace llvm {
 namespace orc {
 
+IRCompileLayer::IRCompiler::~IRCompiler() {}
+
 IRCompileLayer::IRCompileLayer(ExecutionSession &ES, ObjectLayer &BaseLayer,
-                                 CompileFunction Compile)
-    : IRLayer(ES), BaseLayer(BaseLayer), Compile(std::move(Compile)) {}
+                               std::unique_ptr<IRCompiler> Compile)
+    : IRLayer(ES, ManglingOpts), BaseLayer(BaseLayer),
+      Compile(std::move(Compile)) {
+  ManglingOpts = &this->Compile->getManglingOptions();
+}
 
 void IRCompileLayer::setNotifyCompiled(NotifyCompiledFunction NotifyCompiled) {
   std::lock_guard<std::mutex> Lock(IRLayerMutex);
@@ -24,7 +29,7 @@ void IRCompileLayer::emit(MaterializationResponsibility R,
                           ThreadSafeModule TSM) {
   assert(TSM && "Module must not be null");
 
-  if (auto Obj = TSM.withModuleDo(Compile)) {
+  if (auto Obj = TSM.withModuleDo(*Compile)) {
     {
       std::lock_guard<std::mutex> Lock(IRLayerMutex);
       if (NotifyCompiled)
diff --git a/llvm/lib/ExecutionEngine/Orc/IRTransformLayer.cpp b/llvm/lib/ExecutionEngine/Orc/IRTransformLayer.cpp
index 845ecc71eb8..511248f83b2 100644
--- a/llvm/lib/ExecutionEngine/Orc/IRTransformLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/IRTransformLayer.cpp
@@ -12,10 +12,10 @@
 namespace llvm {
 namespace orc {
 
-IRTransformLayer::IRTransformLayer(ExecutionSession &ES,
-                                     IRLayer &BaseLayer,
-                                     TransformFunction Transform)
-    : IRLayer(ES), BaseLayer(BaseLayer), Transform(std::move(Transform)) {}
+IRTransformLayer::IRTransformLayer(ExecutionSession &ES, IRLayer &BaseLayer,
+                                   TransformFunction Transform)
+    : IRLayer(ES, BaseLayer.getManglingOptions()), BaseLayer(BaseLayer),
+      Transform(std::move(Transform)) {}
 
 void IRTransformLayer::emit(MaterializationResponsibility R,
                             ThreadSafeModule TSM) {
diff --git a/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp b/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp
index 3222882c5f0..6189056b3d9 100644
--- a/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp
@@ -107,7 +107,7 @@ LLJIT::createObjectLinkingLayer(LLJITBuilderState &S, ExecutionSession &ES) {
   return std::unique_ptr<ObjectLayer>(std::move(ObjLinkingLayer));
 }
 
-Expected<IRCompileLayer::CompileFunction>
+Expected<std::unique_ptr<IRCompileLayer::IRCompiler>>
 LLJIT::createCompileFunction(LLJITBuilderState &S,
                              JITTargetMachineBuilder JTMB) {
 
@@ -118,13 +118,13 @@ LLJIT::createCompileFunction(LLJITBuilderState &S,
   // Otherwise default to creating a SimpleCompiler, or ConcurrentIRCompiler,
   // depending on the number of threads requested.
   if (S.NumCompileThreads > 0)
-    return ConcurrentIRCompiler(std::move(JTMB));
+    return std::make_unique<ConcurrentIRCompiler>(std::move(JTMB));
 
   auto TM = JTMB.createTargetMachine();
   if (!TM)
     return TM.takeError();
 
-  return TMOwningSimpleCompiler(std::move(*TM));
+  return std::make_unique<TMOwningSimpleCompiler>(std::move(*TM));
 }
 
 LLJIT::LLJIT(LLJITBuilderState &S, Error &Err)
diff --git a/llvm/lib/ExecutionEngine/Orc/Layer.cpp b/llvm/lib/ExecutionEngine/Orc/Layer.cpp
index 580e2682ec8..ebc7801f11f 100644
--- a/llvm/lib/ExecutionEngine/Orc/Layer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/Layer.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ExecutionEngine/Orc/Layer.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Debug.h"
 
@@ -15,15 +16,15 @@
 namespace llvm {
 namespace orc {
 
-IRLayer::IRLayer(ExecutionSession &ES) : ES(ES) {}
 IRLayer::~IRLayer() {}
 
 Error IRLayer::add(JITDylib &JD, ThreadSafeModule TSM, VModuleKey K) {
   return JD.define(std::make_unique<BasicIRLayerMaterializationUnit>(
-      *this, std::move(K), std::move(TSM)));
+      *this, *getManglingOptions(), std::move(TSM), std::move(K)));
 }
 
 IRMaterializationUnit::IRMaterializationUnit(ExecutionSession &ES,
+                                             const ManglingOptions &MO,
                                              ThreadSafeModule TSM, VModuleKey K)
     : MaterializationUnit(SymbolFlagsMap(), std::move(K)), TSM(std::move(TSM)) {
 
@@ -32,12 +33,44 @@ IRMaterializationUnit::IRMaterializationUnit(ExecutionSession &ES,
   MangleAndInterner Mangle(ES, this->TSM.getModuleUnlocked()->getDataLayout());
   this->TSM.withModuleDo([&](Module &M) {
     for (auto &G : M.global_values()) {
-      if (G.hasName() && !G.isDeclaration() && !G.hasLocalLinkage() &&
-          !G.hasAvailableExternallyLinkage() && !G.hasAppendingLinkage()) {
-        auto MangledName = Mangle(G.getName());
-        SymbolFlags[MangledName] = JITSymbolFlags::fromGlobalValue(G);
-        SymbolToDefinition[MangledName] = &G;
+      // Skip globals that don't generate symbols.
+      if (!G.hasName() || G.isDeclaration() || G.hasLocalLinkage() ||
+          G.hasAvailableExternallyLinkage() || G.hasAppendingLinkage())
+        continue;
+
+      // thread locals generate different symbols depending on whether or not
+      // emulated TLS is enabled.
+      if (G.isThreadLocal() && MO.EmulatedTLS) {
+        auto &GV = cast<GlobalVariable>(G);
+
+        auto Flags = JITSymbolFlags::fromGlobalValue(GV);
+
+        auto EmuTLSV = Mangle(("__emutls_v." + GV.getName()).str());
+        SymbolFlags[EmuTLSV] = Flags;
+        SymbolToDefinition[EmuTLSV] = &GV;
+
+        // If this GV has a non-zero initializer we'll need to emit an
+        // __emutls.t symbol too.
+        if (GV.hasInitializer()) {
+          const auto *InitVal = GV.getInitializer();
+
+          // Skip zero-initializers.
+          if (isa<ConstantAggregateZero>(InitVal))
+            continue;
+          const auto *InitIntValue = dyn_cast<ConstantInt>(InitVal);
+          if (InitIntValue && InitIntValue->isZero())
+            continue;
+
+          auto EmuTLST = Mangle(("__emutls_t." + GV.getName()).str());
+          SymbolFlags[EmuTLST] = Flags;
+        }
+        continue;
       }
+
+      // Otherwise we just need a normal linker mangling.
+      auto MangledName = Mangle(G.getName());
+      SymbolFlags[MangledName] = JITSymbolFlags::fromGlobalValue(G);
+      SymbolToDefinition[MangledName] = &G;
     }
   });
 }
@@ -72,8 +105,8 @@ void IRMaterializationUnit::discard(const JITDylib &JD,
 }
 
 BasicIRLayerMaterializationUnit::BasicIRLayerMaterializationUnit(
-    IRLayer &L, VModuleKey K, ThreadSafeModule TSM)
-    : IRMaterializationUnit(L.getExecutionSession(), std::move(TSM),
+    IRLayer &L, const ManglingOptions &MO, ThreadSafeModule TSM, VModuleKey K)
+    : IRMaterializationUnit(L.getExecutionSession(), MO, std::move(TSM),
                             std::move(K)),
       L(L), K(std::move(K)) {}