Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -68,6 +68,8 @@
   endif()
 endif()
 
+set(LLVM_BUILD_GLOBAL_ISEL OFF CACHE BOOL "Experimental: Build GlobalISel")
+
 set(LLVM_PARALLEL_LINK_JOBS "" CACHE STRING
   "Define the maximum number of concurrent link jobs.")
 if(LLVM_PARALLEL_LINK_JOBS)
Index: include/llvm/CodeGen/GlobalISel/IRTranslator.h
===================================================================
--- /dev/null
+++ include/llvm/CodeGen/GlobalISel/IRTranslator.h
@@ -0,0 +1,127 @@
+//===-- llvm/CodeGen/GlobalISel/IRTranslator.h - IRTranslator ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares the IRTranslator pass.
+/// This pass is responsible for translating LLVM IR into MachineInstr.
+/// It uses target hooks to lower the ABI but aside from that, the pass
+/// generated code is generic. This is the default translator used for
+/// GlobalISel.
+///
+/// \todo Replace the comments with actual doxygen comments.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_GLOBALISEL_IRTRANSLATOR_H
+#define LLVM_CODEGEN_GLOBALISEL_IRTRANSLATOR_H
+
+#include "Types.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/IR/Constants.h"
+
+namespace llvm {
+// Forward declarations.
+class Constant;
+class Instruction;
+class MachineInstr;
+class MachineIRBuilder;
+
+// Technically the pass should run on an hypothetical MachineModule,
+// since it should translate Global into some sort of MachineGlobal.
+// The MachineGlobal should ultimately just be a transfer of ownership of
+// the interesting bits that are relevant to represent a global value.
+// That being said, we could investigate what would it cost to just duplicate
+// the information from the LLVM IR.
+// The idea is that ultimately we would be able to free up the memory used
+// by the LLVM IR as soon as the translation is over.
+class IRTranslator : public MachineFunctionPass {
+public:
+  static char ID;
+
+private:
+  // Interface used to lower the everything related to calls.
+  //  TargetLowering *CallLowering;
+  // Mapping of the values of the current LLVM IR function
+  // to the related virtual registers.
+  // We need several virtual registers for the lowering of things
+  // like structures. Right now, this is just a list of virtual
+  // registers, but we would need to encapsulate that in a higher
+  // level class.
+  ValueToVRegs ValToVRegs;
+  // Mapping of a constant to the instructions to produce
+  // that constant.
+  // Constants are special because when we encounter one,
+  // we do not know at first where to insert the definition since
+  // this depends on all its uses.
+  // Thus, we will insert the sequences to materialize them when
+  // we know all their users.
+  // In the meantime, just keep it in a map.
+  // Note: Constants that end up as immediate in the related instructions,
+  // do not appear in that map.
+  DenseMap<const Constant *, SmallVector<MachineInstr *, 1>> ConstantToSequence;
+
+  /* A bunch of methods targeting ADD, SUB, etc. */
+  // Return true if the translation was successful, false
+  // otherwise.
+  // Note: The MachineIRBuilder would encapsulate a
+  // MachineRegisterInfo to create virtual registers.
+  //
+  // Algo:
+  // 1. Look for a virtual register for each operand or
+  //    create one.
+  // 2 Update the ValToVReg accordingly.
+  // 2.alt. For constant arguments, if they are compile time constants,
+  //   produce an immediate in the right operand and do not touch
+  //   ValToReg. Otherwise, update ValToVReg and register the
+  //   sequence to materialize the constant in ConstantToSequence.
+  // 3. Create the generic instruction.
+  bool translateADD(const Instruction &Inst);
+
+  // Builder for machine instruction a la IRBuilder.
+  // I.e., compared to regular MIBuilder, this one also inserts the instruction
+  // in the current block, it can creates block, etc., basically a kind of
+  // IRBuilder, but for Machine IR.
+  MachineIRBuilder *MIRBuilder;
+
+  // Return true if the translation from LLVM IR to Machine IR
+  // suceeded.
+  // See translateXXX for details.
+  bool translate(const Instruction &);
+
+  // * Insert all the code needed to materialize the constants
+  // at the proper place. E.g., Entry block or dominator block
+  // of each constant depending ob how fancy we want to be.
+  // * Clear the different maps.
+  void finalize();
+public:
+  // Ctor, nothing fancy.
+  IRTranslator();
+
+  // Instead of having the instance of the IRTranslatorToolkit
+  // as an argument of the constructor of IRTranslator, we ask
+  // the target the instance of the toolkit for each MachineFunction.
+  // The interest is that we may have different translator for different
+  // subtract or optimization. E.g., we could have a translator optimized
+  // to produce small code size.
+  //
+  // Algo:
+  //   CallLowering = MF.subtarget.getCallLowering()
+  //   F = MF.getParent()
+  //   MIRBuilder.reset(MF)
+  //   MIRBuilder.getOrCreateBB(F.getEntryBB())
+  //   CallLowering->translateArguments(MIRBuilder, F, ValToVReg)
+  //   for each bb in F
+  //     MIRBuilder.getOrCreateBB(bb)
+  //     for each inst in bb
+  //       if (!translate(MIRBuilder, inst, ValToVReg, ConstantToSequence))
+  //         report_fatal_error(“Don’t know how to translate input");
+  //   finalize()
+  bool runOnMachineFunction(MachineFunction &MF) override;
+};
+
+} // End namespace llvm.
+#endif
Index: include/llvm/CodeGen/GlobalISel/Types.h
===================================================================
--- /dev/null
+++ include/llvm/CodeGen/GlobalISel/Types.h
@@ -0,0 +1,34 @@
+//===-- llvm/CodeGen/GlobalISel/Types.h - Types used by GISel ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file describes high level types that are used by several passes or
+/// APIs involved in the GlobalISel pipeline.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_GLOBALISEL_TYPES_H
+#define LLVM_CODEGEN_GLOBALISEL_TYPES_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/Value.h"
+
+namespace llvm {
+
+/// Map a value to virtual registers.
+/// We must support several virtual registers for a value.
+/// Indeed each virtual register is mapped to one EVT, but a value
+/// may span over several EVT when it is a type representing a structure.
+/// In that case the value will be break into EVTs.
+/// Note: We need to expose this type to the target hooks for thing like
+/// ABI lowering that would be used during IRTranslation.
+typedef DenseMap<const Value *, SmallVector<unsigned, 1>> ValueToVRegs;
+
+} // End namespace llvm.
+#endif
Index: lib/CodeGen/CMakeLists.txt
===================================================================
--- lib/CodeGen/CMakeLists.txt
+++ lib/CodeGen/CMakeLists.txt
@@ -145,3 +145,6 @@
 add_subdirectory(SelectionDAG)
 add_subdirectory(AsmPrinter)
 add_subdirectory(MIRParser)
+if(LLVM_BUILD_GLOBAL_ISEL)
+  add_subdirectory(GlobalISel)
+endif()
Index: lib/CodeGen/GlobalISel/CMakeLists.txt
===================================================================
--- /dev/null
+++ lib/CodeGen/GlobalISel/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_llvm_library(LLVMGlobalISel
+        IRTranslator.cpp
+  )
+
+add_dependencies(LLVMGlobalISel intrinsics_gen)
Index: lib/CodeGen/GlobalISel/IRTranslator.cpp
===================================================================
--- /dev/null
+++ lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -0,0 +1,37 @@
+//===-- llvm/CodeGen/GlobalISel/IRTranslator.cpp - IRTranslator --*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the IRTranslator class.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/GlobalISel/IRTranslator.h"
+
+using namespace llvm;
+
+char IRTranslator::ID = 0;
+
+bool IRTranslator::translateADD(const Instruction &Inst) {
+  return false;
+}
+
+bool IRTranslator::translate(const Instruction &) {
+  return false;
+}
+
+
+void IRTranslator::finalize() {
+}
+
+IRTranslator::IRTranslator()
+  : MachineFunctionPass(ID) {
+}
+
+bool IRTranslator::runOnMachineFunction(MachineFunction &MF) {
+  return false;
+}
Index: lib/CodeGen/GlobalISel/LLVMBuild.txt
===================================================================
--- /dev/null
+++ lib/CodeGen/GlobalISel/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/CodeGen/GlobalISel/LLVMBuild.txt -----------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = GlobalISel
+parent = CodeGen
+required_libraries = Analysis CodeGen Core MC Support Target TransformUtils
Index: lib/CodeGen/LLVMBuild.txt
===================================================================
--- lib/CodeGen/LLVMBuild.txt
+++ lib/CodeGen/LLVMBuild.txt
@@ -16,7 +16,7 @@
 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = AsmPrinter SelectionDAG MIRParser
+subdirectories = AsmPrinter SelectionDAG MIRParser GlobalISel
 
 [component_0]
 type = Library
Index: tools/llc/CMakeLists.txt
===================================================================
--- tools/llc/CMakeLists.txt
+++ tools/llc/CMakeLists.txt
@@ -1,3 +1,10 @@
+# Add GlobalISel to the dependencies if the user wants to build it.
+if(LLVM_BUILD_GLOBAL_ISEL)
+  set(GLOBAL_ISEL GlobalISel)
+else()
+  set(GLOBAL_ISEL "")
+endif()
+
 set(LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   Analysis
@@ -5,6 +12,7 @@
   CodeGen
   Core
   IRReader
+  ${GLOBAL_ISEL}
   MC
   MIRParser
   ScalarOpts