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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215154 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ExecutionEngine/ExecutionEngine.h

@@ -141,6 +141,12 @@ protected:
   // To avoid having libexecutionengine depend on the JIT and interpreter
   // libraries, the execution engine implementations set these functions to ctor
   // pointers at startup time if they are linked in.
+  static ExecutionEngine *(*JITCtor)(
+    Module *M,
+    std::string *ErrorStr,
+    JITMemoryManager *JMM,
+    bool GVsWithCode,
+    TargetMachine *TM);
   static ExecutionEngine *(*MCJITCtor)(
     Module *M,
     std::string *ErrorStr,
@@ -329,6 +335,13 @@ public:
   /// getFunctionAddress instead.
   virtual void *getPointerToFunction(Function *F) = 0;
 
+  /// getPointerToBasicBlock - The different EE's represent basic blocks in
+  /// different ways.  Return the representation for a blockaddress of the
+  /// specified block.
+  ///
+  /// This function will not be implemented for the MCJIT execution engine.
+  virtual void *getPointerToBasicBlock(BasicBlock *BB) = 0;
+
   /// getPointerToFunctionOrStub - If the specified function has been
   /// code-gen'd, return a pointer to the function.  If not, compile it, or use
   /// a stub to implement lazy compilation if available.  See
@@ -376,6 +389,18 @@ public:
 
   void InitializeMemory(const Constant *Init, void *Addr);
 
+  /// recompileAndRelinkFunction - This method is used to force a function which
+  /// has already been compiled to be compiled again, possibly after it has been
+  /// modified.  Then the entry to the old copy is overwritten with a branch to
+  /// the new copy.  If there was no old copy, this acts just like
+  /// VM::getPointerToFunction().
+  virtual void *recompileAndRelinkFunction(Function *F) = 0;
+
+  /// freeMachineCodeForFunction - Release memory in the ExecutionEngine
+  /// corresponding to the machine code emitted to execute this function, useful
+  /// for garbage-collecting generated code.
+  virtual void freeMachineCodeForFunction(Function *F) = 0;
+
   /// getOrEmitGlobalVariable - Return the address of the specified global
   /// variable, possibly emitting it to memory if needed.  This is used by the
   /// Emitter.
@@ -512,12 +537,14 @@ private:
   CodeGenOpt::Level OptLevel;
   RTDyldMemoryManager *MCJMM;
   JITMemoryManager *JMM;
+  bool AllocateGVsWithCode;
   TargetOptions Options;
   Reloc::Model RelocModel;
   CodeModel::Model CMModel;
   std::string MArch;
   std::string MCPU;
   SmallVector<std::string, 4> MAttrs;
+  bool UseMCJIT;
   bool VerifyModules;
 
   /// InitEngine - Does the common initialization of default options.
@@ -599,6 +626,18 @@ public:
     return *this;
   }
 
+  /// setAllocateGVsWithCode - Sets whether global values should be allocated
+  /// into the same buffer as code.  For most applications this should be set
+  /// to false.  Allocating globals with code breaks freeMachineCodeForFunction
+  /// and is probably unsafe and bad for performance.  However, we have clients
+  /// who depend on this behavior, so we must support it.  This option defaults
+  /// to false so that users of the new API can safely use the new memory
+  /// manager and free machine code.
+  EngineBuilder &setAllocateGVsWithCode(bool a) {
+    AllocateGVsWithCode = a;
+    return *this;
+  }
+
   /// setMArch - Override the architecture set by the Module's triple.
   EngineBuilder &setMArch(StringRef march) {
     MArch.assign(march.begin(), march.end());
@@ -611,6 +650,13 @@ public:
     return *this;
   }
 
+  /// setUseMCJIT - Set whether the MC-JIT implementation should be used
+  /// (experimental).
+  EngineBuilder &setUseMCJIT(bool Value) {
+    UseMCJIT = Value;
+    return *this;
+  }
+
   /// setVerifyModules - Set whether the JIT implementation should verify
   /// IR modules during compilation.
   EngineBuilder &setVerifyModules(bool Verify) {