Temporarily Revert "Nuke the old JIT." as it's not quite ready to

be deleted. This will be reapplied as soon as possible and before
the 3.6 branch date at any rate.

Approved by Jim Grosbach, Lang Hames, Rafael Espindola.

This reverts commits r215111, 215115, 215116, 215117, 215136.

llvm-svn: 215154

llvm/lib/ExecutionEngine/ExecutionEngine.cpp

@@ -48,6 +48,12 @@ void ObjectCache::anchor() {}
 void ObjectBuffer::anchor() {}
 void ObjectBufferStream::anchor() {}
 
+ExecutionEngine *(*ExecutionEngine::JITCtor)(
+  Module *M,
+  std::string *ErrorStr,
+  JITMemoryManager *JMM,
+  bool GVsWithCode,
+  TargetMachine *TM) = nullptr;
 ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
   Module *M,
   std::string *ErrorStr,
@@ -411,8 +417,10 @@ void EngineBuilder::InitEngine() {
   MCJMM = nullptr;
   JMM = nullptr;
   Options = TargetOptions();
+  AllocateGVsWithCode = false;
   RelocModel = Reloc::Default;
   CMModel = CodeModel::JITDefault;
+  UseMCJIT = false;
 
 // IR module verification is enabled by default in debug builds, and disabled
 // by default in release builds.
@@ -445,6 +453,14 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
       return nullptr;
     }
   }
+  
+  if (MCJMM && ! UseMCJIT) {
+    if (ErrorStr)
+      *ErrorStr =
+        "Cannot create a legacy JIT with a runtime dyld memory "
+        "manager.";
+    return nullptr;
+  }
 
   // Unless the interpreter was explicitly selected or the JIT is not linked,
   // try making a JIT.
@@ -457,9 +473,12 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
     }
 
     ExecutionEngine *EE = nullptr;
-    if (ExecutionEngine::MCJITCtor)
+    if (UseMCJIT && ExecutionEngine::MCJITCtor)
       EE = ExecutionEngine::MCJITCtor(M, ErrorStr, MCJMM ? MCJMM : JMM,
                                       TheTM.release());
+    else if (ExecutionEngine::JITCtor)
+      EE = ExecutionEngine::JITCtor(M, ErrorStr, JMM,
+                                    AllocateGVsWithCode, TheTM.release());
 
     if (EE) {
       EE->setVerifyModules(VerifyModules);
@@ -477,7 +496,8 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
     return nullptr;
   }
 
-  if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::MCJITCtor) {
+  if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::JITCtor &&
+      !ExecutionEngine::MCJITCtor) {
     if (ErrorStr)
       *ErrorStr = "JIT has not been linked in.";
   }
@@ -823,6 +843,9 @@ GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
       Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
     else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
       Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
+    else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C))
+      Result = PTOGV(getPointerToBasicBlock(const_cast<BasicBlock*>(
+                                                        BA->getBasicBlock())));
     else
       llvm_unreachable("Unknown constant pointer type!");
     break;