This patch enables llvm to switch between compiling for mips32/mips64 
and mips16 on a per function basis.

Because this patch is somewhat involved I have provide an overview of the
key pieces of it.

The patch is written so as to not change the behavior of the non mixed
mode. We have tested this a lot but it is something new to switch subtargets
so we don't want any chance of regression in the mainline compiler until
we have more confidence in this.

Mips32/64 are very different from Mip16 as is the case of ARM vs Thumb1.
For that reason there are derived versions of the register info, frame info, 
instruction info and instruction selection classes.

Now we register three separate passes for instruction selection.
One which is used to switch subtargets (MipsModuleISelDAGToDAG.cpp) and then
one for each of the current subtargets (Mips16ISelDAGToDAG.cpp and
MipsSEISelDAGToDAG.cpp).

When the ModuleISel pass runs, it determines if there is a need to switch
subtargets and if so, the owning pointers in MipsTargetMachine are
appropriately changed.

When 16Isel or SEIsel is run, they will return immediately without doing
any work if the current subtarget mode does not apply to them.

In addition, MipsAsmPrinter needs to be reset on a function basis.

The pass BasicTargetTransformInfo is substituted with a null pass since the
pass is immutable and really needs to be a function pass for it to be
used with changing subtargets. This will be fixed in a follow on patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179118 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/CMakeLists.txt b/lib/Target/Mips/CMakeLists.txt
index cf8bb18..a75e8bd 100644
--- a/lib/Target/Mips/CMakeLists.txt
+++ b/lib/Target/Mips/CMakeLists.txt
@@ -32,6 +32,7 @@
   MipsLongBranch.cpp
   MipsMCInstLower.cpp
   MipsMachineFunction.cpp
+  MipsModuleISelDAGToDAG.cpp
   MipsRegisterInfo.cpp
   MipsSEFrameLowering.cpp
   MipsSEInstrInfo.cpp
diff --git a/lib/Target/Mips/Mips16ISelDAGToDAG.cpp b/lib/Target/Mips/Mips16ISelDAGToDAG.cpp
index 00b3449..2ffd3a9 100644
--- a/lib/Target/Mips/Mips16ISelDAGToDAG.cpp
+++ b/lib/Target/Mips/Mips16ISelDAGToDAG.cpp
@@ -35,6 +35,11 @@
 #include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
+bool Mips16DAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
+  if (!Subtarget.inMips16Mode())
+    return false;
+  return MipsDAGToDAGISel::runOnMachineFunction(MF);
+}
 /// Select multiply instructions.
 std::pair<SDNode*, SDNode*>
 Mips16DAGToDAGISel::selectMULT(SDNode *N, unsigned Opc, DebugLoc DL, EVT Ty,
diff --git a/lib/Target/Mips/Mips16ISelDAGToDAG.h b/lib/Target/Mips/Mips16ISelDAGToDAG.h
index baa8587..f05f9b7 100644
--- a/lib/Target/Mips/Mips16ISelDAGToDAG.h
+++ b/lib/Target/Mips/Mips16ISelDAGToDAG.h
@@ -28,6 +28,8 @@
 
   SDValue getMips16SPAliasReg();
 
+  virtual bool runOnMachineFunction(MachineFunction &MF);
+
   void getMips16SPRefReg(SDNode *Parent, SDValue &AliasReg);
 
   virtual bool selectAddr16(SDNode *Parent, SDValue N, SDValue &Base,
diff --git a/lib/Target/Mips/MipsAsmPrinter.cpp b/lib/Target/Mips/MipsAsmPrinter.cpp
index 1876cb6..e0ddade 100644
--- a/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -46,6 +46,10 @@
 using namespace llvm;
 
 bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
+  // Initialize TargetLoweringObjectFile.
+  if (Subtarget->allowMixed16_32())
+    const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
+      .Initialize(OutContext, TM);
   MipsFI = MF.getInfo<MipsFunctionInfo>();
   AsmPrinter::runOnMachineFunction(MF);
   return true;
diff --git a/lib/Target/Mips/MipsConstantIslandPass.cpp b/lib/Target/Mips/MipsConstantIslandPass.cpp
index b5de1eb..1951324 100644
--- a/lib/Target/Mips/MipsConstantIslandPass.cpp
+++ b/lib/Target/Mips/MipsConstantIslandPass.cpp
@@ -80,6 +80,10 @@
 }
 
 bool MipsConstantIslands::runOnMachineFunction(MachineFunction &F) {
-  return true;
+  // The intention is for this to be a mips16 only pass for now
+  // FIXME:
+  // if (!TM.getSubtarget<MipsSubtarget>().inMips16Mode())
+  //  return false;
+  return false;
 }
 
diff --git a/lib/Target/Mips/MipsLongBranch.cpp b/lib/Target/Mips/MipsLongBranch.cpp
index 2efe534..bf5ad37 100644
--- a/lib/Target/Mips/MipsLongBranch.cpp
+++ b/lib/Target/Mips/MipsLongBranch.cpp
@@ -399,6 +399,8 @@
 }
 
 bool MipsLongBranch::runOnMachineFunction(MachineFunction &F) {
+  if (TM.getSubtarget<MipsSubtarget>().inMips16Mode())
+    return false;
   if ((TM.getRelocationModel() == Reloc::PIC_) &&
       TM.getSubtarget<MipsSubtarget>().isABI_O32() &&
       F.getInfo<MipsFunctionInfo>()->globalBaseRegSet())
diff --git a/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp b/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp
new file mode 100644
index 0000000..c6abf17
--- /dev/null
+++ b/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+// Instruction Selector Subtarget Control
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// This file defines a pass used to change the subtarget for the
+// Mips Instruction selector.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MipsISelDAGToDAG.h"
+#include "MipsModuleISelDAGToDAG.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+
+bool MipsModuleDAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
+  DEBUG(errs() << "In MipsModuleDAGToDAGISel::runMachineFunction\n");
+  const_cast<MipsSubtarget&>(Subtarget).resetSubtarget(&MF);
+  return false;
+}
+
+char MipsModuleDAGToDAGISel::ID = 0;
+
+}
+
+
+llvm::FunctionPass *llvm::createMipsModuleISelDag(MipsTargetMachine &TM) {
+  return new MipsModuleDAGToDAGISel(TM);
+}
+
+
diff --git a/lib/Target/Mips/MipsModuleISelDAGToDAG.h b/lib/Target/Mips/MipsModuleISelDAGToDAG.h
new file mode 100644
index 0000000..fda35ae
--- /dev/null
+++ b/lib/Target/Mips/MipsModuleISelDAGToDAG.h
@@ -0,0 +1,66 @@
+//===---- MipsModuleISelDAGToDAG.h -  Change Subtarget             --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a pass used to change the subtarget for the
+// Mips Instruction selector.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MIPSMODULEISELDAGTODAG_H
+#define MIPSMODULEISELDAGTODAG_H
+
+#include "Mips.h"
+#include "MipsSubtarget.h"
+#include "MipsTargetMachine.h"
+#include "llvm/CodeGen/SelectionDAGISel.h"
+
+
+//===----------------------------------------------------------------------===//
+// Instruction Selector Implementation
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// MipsModuleDAGToDAGISel - MIPS specific code to select MIPS machine
+// instructions for SelectionDAG operations.
+//===----------------------------------------------------------------------===//
+namespace llvm {
+
+class MipsModuleDAGToDAGISel : public MachineFunctionPass {
+public:
+
+  static char ID;
+
+  explicit MipsModuleDAGToDAGISel(MipsTargetMachine &TM_)
+    : MachineFunctionPass(ID),
+      TM(TM_), Subtarget(TM.getSubtarget<MipsSubtarget>()) {}
+
+  // Pass Name
+  virtual const char *getPassName() const {
+    return "MIPS DAG->DAG Pattern Instruction Selection";
+  }
+
+  virtual bool runOnMachineFunction(MachineFunction &MF);
+
+  virtual SDNode *Select(SDNode *N) {
+    llvm_unreachable("unexpected");
+  }
+
+protected:
+  /// Keep a pointer to the MipsSubtarget around so that we can make the right
+  /// decision when generating code for different targets.
+  const TargetMachine &TM;
+  const MipsSubtarget &Subtarget;
+};
+
+/// createMipsISelDag - This pass converts a legalized DAG into a
+/// MIPS-specific DAG, ready for instruction scheduling.
+FunctionPass *createMipsModuleISelDag(MipsTargetMachine &TM);
+}
+
+#endif
diff --git a/lib/Target/Mips/MipsSEISelDAGToDAG.cpp b/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
index d6d2207..0fc3c5e 100644
--- a/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
@@ -35,6 +35,11 @@
 #include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
+bool MipsSEDAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
+  if (Subtarget.inMips16Mode())
+    return false;
+  return MipsDAGToDAGISel::runOnMachineFunction(MF);
+}
 
 bool MipsSEDAGToDAGISel::replaceUsesWithZeroReg(MachineRegisterInfo *MRI,
                                                 const MachineInstr& MI) {
diff --git a/lib/Target/Mips/MipsSEISelDAGToDAG.h b/lib/Target/Mips/MipsSEISelDAGToDAG.h
index 6137ab0..0dae73d 100644
--- a/lib/Target/Mips/MipsSEISelDAGToDAG.h
+++ b/lib/Target/Mips/MipsSEISelDAGToDAG.h
@@ -24,6 +24,9 @@
   explicit MipsSEDAGToDAGISel(MipsTargetMachine &TM) : MipsDAGToDAGISel(TM) {}
 
 private:
+
+  virtual bool runOnMachineFunction(MachineFunction &MF);
+
   bool replaceUsesWithZeroReg(MachineRegisterInfo *MRI, const MachineInstr&);
 
   std::pair<SDNode*, SDNode*> selectMULT(SDNode *N, unsigned Opc, DebugLoc dl,
diff --git a/lib/Target/Mips/MipsSEISelLowering.cpp b/lib/Target/Mips/MipsSEISelLowering.cpp
index 4f21921..df6af09 100644
--- a/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -27,6 +27,9 @@
 MipsSETargetLowering::MipsSETargetLowering(MipsTargetMachine &TM)
   : MipsTargetLowering(TM) {
   // Set up the register classes
+
+  clearRegisterClasses();
+
   addRegisterClass(MVT::i32, &Mips::CPURegsRegClass);
 
   if (HasMips64)
diff --git a/lib/Target/Mips/MipsSubtarget.cpp b/lib/Target/Mips/MipsSubtarget.cpp
index e11e5d1..b91f547 100644
--- a/lib/Target/Mips/MipsSubtarget.cpp
+++ b/lib/Target/Mips/MipsSubtarget.cpp
@@ -11,29 +11,49 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define DEBUG_TYPE "mips-subtarget"
+
+#include "MipsMachineFunction.h"
 #include "MipsSubtarget.h"
+#include "MipsTargetMachine.h"
 #include "Mips.h"
 #include "MipsRegisterInfo.h"
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/raw_ostream.h"
 
 #define GET_SUBTARGETINFO_TARGET_DESC
 #define GET_SUBTARGETINFO_CTOR
 #include "MipsGenSubtargetInfo.inc"
 
+
 using namespace llvm;
 
+// FIXME: Maybe this should be on by default when Mips16 is specified
+//
+static cl::opt<bool> Mixed16_32(
+  "mips-mixed-16-32",
+  cl::init(false),
+  cl::desc("Allow for a mixture of Mips16 "
+           "and Mips32 code in a single source file"),
+  cl::Hidden);
+
 void MipsSubtarget::anchor() { }
 
 MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
                              const std::string &FS, bool little,
-                             Reloc::Model _RM) :
+                             Reloc::Model _RM, MipsTargetMachine *_TM) :
   MipsGenSubtargetInfo(TT, CPU, FS),
   MipsArchVersion(Mips32), MipsABI(UnknownABI), IsLittle(little),
   IsSingleFloat(false), IsFP64bit(false), IsGP64bit(false), HasVFPU(false),
   IsLinux(true), HasSEInReg(false), HasCondMov(false), HasSwap(false),
   HasBitCount(false), HasFPIdx(false),
   InMips16Mode(false), InMicroMipsMode(false), HasDSP(false), HasDSPR2(false),
-  RM(_RM)
+  AllowMixed16_32(Mixed16_32),
+  RM(_RM), OverrideMode(NoOverride), TM(_TM)
 {
   std::string CPUName = CPU;
   if (CPUName.empty())
@@ -42,6 +62,8 @@
   // Parse features string.
   ParseSubtargetFeatures(CPUName, FS);
 
+  PreviousInMips16Mode = InMips16Mode;
+
   // Initialize scheduling itinerary for the specified CPU.
   InstrItins = getInstrItineraryForCPU(CPUName);
 
@@ -72,3 +94,48 @@
                             &Mips::CPU64RegsRegClass : &Mips::CPURegsRegClass);
   return OptLevel >= CodeGenOpt::Aggressive;
 }
+
+//FIXME: This logic for reseting the subtarget along with
+// the helper classes can probably be simplified but there are a lot of
+// cases so we will defer rewriting this to later.
+//
+void MipsSubtarget::resetSubtarget(MachineFunction *MF) {
+  bool ChangeToMips16 = false, ChangeToNoMips16 = false;
+  DEBUG(dbgs() << "resetSubtargetFeatures" << "\n");
+  AttributeSet FnAttrs = MF->getFunction()->getAttributes();
+  ChangeToMips16 = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
+                                        "mips16");
+  ChangeToNoMips16 = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
+                                        "nomips16");
+  assert (!(ChangeToMips16 & ChangeToNoMips16) &&
+          "mips16 and nomips16 specified on the same function");
+  if (ChangeToMips16) {
+    if (PreviousInMips16Mode)
+      return;
+    OverrideMode = Mips16Override;
+    PreviousInMips16Mode = true;
+    TM->setHelperClassesMips16();
+    return;
+  } else if (ChangeToNoMips16) {
+    if (!PreviousInMips16Mode)
+      return;
+    OverrideMode = NoMips16Override;
+    PreviousInMips16Mode = false;
+    TM->setHelperClassesMipsSE();
+    return;
+  } else {
+    if (OverrideMode == NoOverride)
+      return;
+    OverrideMode = NoOverride;
+    DEBUG(dbgs() << "back to default" << "\n");
+    if (inMips16Mode() && !PreviousInMips16Mode) {
+      TM->setHelperClassesMips16();
+      PreviousInMips16Mode = true;
+    } else if (!inMips16Mode() && PreviousInMips16Mode) {
+      TM->setHelperClassesMipsSE();
+      PreviousInMips16Mode = false;
+    }
+    return;
+  }
+}
+
diff --git a/lib/Target/Mips/MipsSubtarget.h b/lib/Target/Mips/MipsSubtarget.h
index 7a2e47c..5ad627c 100644
--- a/lib/Target/Mips/MipsSubtarget.h
+++ b/lib/Target/Mips/MipsSubtarget.h
@@ -16,7 +16,9 @@
 
 #include "MCTargetDesc/MipsReginfo.h"
 #include "llvm/MC/MCInstrItineraries.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
+
 #include <string>
 
 #define GET_SUBTARGETINFO_HEADER
@@ -25,6 +27,8 @@
 namespace llvm {
 class StringRef;
 
+class MipsTargetMachine;
+
 class MipsSubtarget : public MipsGenSubtargetInfo {
   virtual void anchor();
 
@@ -89,12 +93,18 @@
   // InMips16 -- can process Mips16 instructions
   bool InMips16Mode;
 
+  // PreviousInMips16 -- the function we just processed was in Mips 16 Mode
+  bool PreviousInMips16Mode;
+
   // InMicroMips -- can process MicroMips instructions
   bool InMicroMipsMode;
 
   // HasDSP, HasDSPR2 -- supports DSP ASE.
   bool HasDSP, HasDSPR2;
 
+  // Allow mixed Mips16 and Mips32 in one source file
+  bool AllowMixed16_32;
+
   InstrItineraryData InstrItins;
 
   // The instance to the register info section object
@@ -103,6 +113,12 @@
   // Relocation Model
   Reloc::Model RM;
 
+  // We can override the determination of whether we are in mips16 mode
+  // as from the command line
+  enum {NoOverride, Mips16Override, NoMips16Override} OverrideMode;
+
+  MipsTargetMachine *TM;
+
 public:
   virtual bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
                                      AntiDepBreakMode& Mode,
@@ -118,7 +134,8 @@
   /// This constructor initializes the data members to match that
   /// of the specified triple.
   MipsSubtarget(const std::string &TT, const std::string &CPU,
-                const std::string &FS, bool little, Reloc::Model RM);
+                const std::string &FS, bool little, Reloc::Model RM,
+                MipsTargetMachine *TM);
 
   /// ParseSubtargetFeatures - Parses features string setting specified
   /// subtarget options.  Definition of function is auto generated by tblgen.
@@ -137,7 +154,20 @@
   bool isSingleFloat() const { return IsSingleFloat; }
   bool isNotSingleFloat() const { return !IsSingleFloat; }
   bool hasVFPU() const { return HasVFPU; }
-  bool inMips16Mode() const { return InMips16Mode; }
+  bool inMips16Mode() const {
+    switch (OverrideMode) {
+    case NoOverride:
+      return InMips16Mode;
+    case Mips16Override:
+      return true;
+    case NoMips16Override:
+      return false;
+    }
+    llvm_unreachable("Unexpected mode");
+  }
+  bool inMips16ModeDefault() {
+    return InMips16Mode;
+  }
   bool inMicroMipsMode() const { return InMicroMipsMode; }
   bool hasDSP() const { return HasDSP; }
   bool hasDSPR2() const { return HasDSPR2; }
@@ -153,11 +183,18 @@
   bool hasBitCount()  const { return HasBitCount; }
   bool hasFPIdx()     const { return HasFPIdx; }
 
+  bool allowMixed16_32() const { return AllowMixed16_32;};
+
   // Grab MipsRegInfo object
   const MipsReginfo &getMReginfo() const { return MRI; }
 
   // Grab relocation model
   Reloc::Model getRelocationModel() const {return RM;}
+
+  /// \brief Reset the subtarget for the Mips target.
+  void resetSubtarget(MachineFunction *MF);
+
+
 };
 } // End llvm namespace
 
diff --git a/lib/Target/Mips/MipsTargetMachine.cpp b/lib/Target/Mips/MipsTargetMachine.cpp
index 3336358..18c1cce 100644
--- a/lib/Target/Mips/MipsTargetMachine.cpp
+++ b/lib/Target/Mips/MipsTargetMachine.cpp
@@ -15,11 +15,25 @@
 #include "Mips.h"
 #include "MipsFrameLowering.h"
 #include "MipsInstrInfo.h"
+#include "MipsModuleISelDAGToDAG.h"
+#include "MipsSEFrameLowering.h"
+#include "MipsSEInstrInfo.h"
+#include "MipsSEISelLowering.h"
+#include "MipsSEISelDAGToDAG.h"
+#include "Mips16FrameLowering.h"
+#include "Mips16InstrInfo.h"
+#include "Mips16ISelDAGToDAG.h"
+#include "Mips16ISelLowering.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/PassManager.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/TargetRegistry.h"
 using namespace llvm;
 
+
+
 extern "C" void LLVMInitializeMipsTarget() {
   // Register the target.
   RegisterTargetMachine<MipsebTargetMachine> X(TheMipsTarget);
@@ -42,7 +56,7 @@
                   CodeGenOpt::Level OL,
                   bool isLittle)
   : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
-    Subtarget(TT, CPU, FS, isLittle, RM),
+    Subtarget(TT, CPU, FS, isLittle, RM, this),
     DL(isLittle ?
                (Subtarget.isABI_N64() ?
                 "e-p:64:64:64-i8:8:32-i16:16:32-i64:64:64-f128:128:128-"
@@ -54,9 +68,46 @@
                 "E-p:32:32:32-i8:8:32-i16:16:32-i64:64:64-n32-S64")),
     InstrInfo(MipsInstrInfo::create(*this)),
     FrameLowering(MipsFrameLowering::create(*this, Subtarget)),
-    TLInfo(MipsTargetLowering::create(*this)), TSInfo(*this), JITInfo() {
+    TLInfo(MipsTargetLowering::create(*this)),
+    TSInfo(*this), JITInfo() {
 }
 
+
+void MipsTargetMachine::setHelperClassesMips16() {
+  InstrInfoSE.swap(InstrInfo);
+  FrameLoweringSE.swap(FrameLowering);
+  TLInfoSE.swap(TLInfo);
+  if (!InstrInfo16) {
+    InstrInfo.reset(MipsInstrInfo::create(*this));
+    FrameLowering.reset(MipsFrameLowering::create(*this, Subtarget));
+    TLInfo.reset(MipsTargetLowering::create(*this));
+  } else {
+    InstrInfo16.swap(InstrInfo);
+    FrameLowering16.swap(FrameLowering);
+    TLInfo16.swap(TLInfo);
+  }
+  assert(TLInfo && "null target lowering 16");
+  assert(InstrInfo && "null instr info 16");
+  assert(FrameLowering && "null frame lowering 16");
+}
+
+void MipsTargetMachine::setHelperClassesMipsSE() {
+  InstrInfo16.swap(InstrInfo);
+  FrameLowering16.swap(FrameLowering);
+  TLInfo16.swap(TLInfo);
+  if (!InstrInfoSE) {
+    InstrInfo.reset(MipsInstrInfo::create(*this));
+    FrameLowering.reset(MipsFrameLowering::create(*this, Subtarget));
+    TLInfo.reset(MipsTargetLowering::create(*this));
+  } else {
+    InstrInfoSE.swap(InstrInfo);
+    FrameLoweringSE.swap(FrameLowering);
+    TLInfoSE.swap(TLInfo);
+  }
+  assert(TLInfo && "null target lowering in SE");
+  assert(InstrInfo && "null instr info SE");
+  assert(FrameLowering && "null frame lowering SE");
+}
 void MipsebTargetMachine::anchor() { }
 
 MipsebTargetMachine::
@@ -102,21 +153,42 @@
 // Install an instruction selector pass using
 // the ISelDag to gen Mips code.
 bool MipsPassConfig::addInstSelector() {
-  addPass(createMipsISelDag(getMipsTargetMachine()));
+  if (getMipsSubtarget().allowMixed16_32()) {
+    addPass(createMipsModuleISelDag(getMipsTargetMachine()));
+    addPass(createMips16ISelDag(getMipsTargetMachine()));
+    addPass(createMipsSEISelDag(getMipsTargetMachine()));
+  } else {
+    addPass(createMipsISelDag(getMipsTargetMachine()));
+  }
   return false;
 }
 
+void MipsTargetMachine::addAnalysisPasses(PassManagerBase &PM) {
+  if (Subtarget.allowMixed16_32()) {
+    DEBUG(errs() << "No ");
+    //FIXME: The Basic Target Transform Info
+    // pass needs to become a function pass instead of
+    // being an immutable pass and then this method as it exists now
+    // would be unnecessary.
+    PM.add(createNoTargetTransformInfoPass());
+  } else
+    LLVMTargetMachine::addAnalysisPasses(PM);
+  DEBUG(errs() << "Target Transform Info Pass Added\n");
+}
+
 // Implemented by targets that want to run passes immediately before
 // machine code is emitted. return true if -print-machineinstrs should
 // print out the code after the passes.
 bool MipsPassConfig::addPreEmitPass() {
   MipsTargetMachine &TM = getMipsTargetMachine();
+  const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>();
   addPass(createMipsDelaySlotFillerPass(TM));
 
-  // NOTE: long branch has not been implemented for mips16.
-  if (TM.getSubtarget<MipsSubtarget>().hasStandardEncoding())
+  if (Subtarget.hasStandardEncoding() ||
+      Subtarget.allowMixed16_32())
     addPass(createMipsLongBranchPass(TM));
-  if (TM.getSubtarget<MipsSubtarget>().inMips16Mode())
+  if (Subtarget.inMips16Mode() ||
+      Subtarget.allowMixed16_32())
     addPass(createMipsConstantIslandPass(TM));
 
   return true;
diff --git a/lib/Target/Mips/MipsTargetMachine.h b/lib/Target/Mips/MipsTargetMachine.h
index 7e5f192..ee55708 100644
--- a/lib/Target/Mips/MipsTargetMachine.h
+++ b/lib/Target/Mips/MipsTargetMachine.h
@@ -21,6 +21,8 @@
 #include "MipsSelectionDAGInfo.h"
 #include "MipsSubtarget.h"
 #include "llvm/ADT/OwningPtr.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/Target/TargetFrameLowering.h"
 #include "llvm/Target/TargetMachine.h"
@@ -35,6 +37,12 @@
   OwningPtr<const MipsInstrInfo> InstrInfo;
   OwningPtr<const MipsFrameLowering> FrameLowering;
   OwningPtr<const MipsTargetLowering> TLInfo;
+  OwningPtr<const MipsInstrInfo> InstrInfo16;
+  OwningPtr<const MipsFrameLowering> FrameLowering16;
+  OwningPtr<const MipsTargetLowering> TLInfo16;
+  OwningPtr<const MipsInstrInfo> InstrInfoSE;
+  OwningPtr<const MipsFrameLowering> FrameLoweringSE;
+  OwningPtr<const MipsTargetLowering> TLInfoSE;
   MipsSelectionDAGInfo TSInfo;
   MipsJITInfo JITInfo;
 
@@ -47,6 +55,8 @@
 
   virtual ~MipsTargetMachine() {}
 
+  virtual void addAnalysisPasses(PassManagerBase &PM);
+
   virtual const MipsInstrInfo *getInstrInfo() const
   { return InstrInfo.get(); }
   virtual const TargetFrameLowering *getFrameLowering() const
@@ -73,6 +83,13 @@
   // Pass Pipeline Configuration
   virtual TargetPassConfig *createPassConfig(PassManagerBase &PM);
   virtual bool addCodeEmitter(PassManagerBase &PM, JITCodeEmitter &JCE);
+
+  // Set helper classes
+  void setHelperClassesMips16();
+
+  void setHelperClassesMipsSE();
+
+
 };
 
 /// MipsebTargetMachine - Mips32/64 big endian target machine.