[Orc] Add setters for target options and features to JITTargetMachineBuilder.

Also remove redundant feature initialization steps from the detectHost method.

llvm/include/llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h

@@ -91,6 +91,12 @@ public:
     return *this;
   }
 
+  /// Set subtarget features.
+  JITTargetMachineBuilder &setFeatures(StringRef FeatureString) {
+    Features = SubtargetFeatures(FeatureString);
+    return *this;
+  }
+
   /// Add subtarget features.
   JITTargetMachineBuilder &
   addFeatures(const std::vector<std::string> &FeatureVec);
@@ -101,6 +107,17 @@ public:
   /// Access subtarget features.
   const SubtargetFeatures &getFeatures() const { return Features; }
 
+  /// Set TargetOptions.
+  ///
+  /// Note: This operation will overwrite any previously configured options,
+  /// including EmulatedTLS and ExplicitEmulatedTLS which
+  /// the JITTargetMachineBuilder sets by default. Clients are responsible
+  /// for re-enabling these overwritten options.
+  JITTargetMachineBuilder &setOptions(TargetOptions Options) {
+    this->Options = std::move(Options);
+    return *this;
+  }
+
   /// Access TargetOptions.
   TargetOptions &getOptions() { return Options; }
 

llvm/lib/ExecutionEngine/Orc/JITTargetMachineBuilder.cpp

@@ -28,14 +28,12 @@ Expected<JITTargetMachineBuilder> JITTargetMachineBuilder::detectHost() {
   // Retrieve host CPU name and sub-target features and add them to builder.
   // Relocation model, code model and codegen opt level are kept to default
   // values.
-  llvm::SubtargetFeatures SubtargetFeatures;
   llvm::StringMap<bool> FeatureMap;
   llvm::sys::getHostCPUFeatures(FeatureMap);
   for (auto &Feature : FeatureMap)
-    SubtargetFeatures.AddFeature(Feature.first(), Feature.second);
+    TMBuilder.getFeatures().AddFeature(Feature.first(), Feature.second);
 
   TMBuilder.setCPU(llvm::sys::getHostCPUName());
-  TMBuilder.addFeatures(SubtargetFeatures.getFeatures());
 
   return TMBuilder;
 }