--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Target/WebAssembly/WebAssemblyRegNumbering.cpp	Tue Jan 26 22:53:40 2016 +0900
@@ -0,0 +1,117 @@
+//===-- WebAssemblyRegNumbering.cpp - Register Numbering ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file implements a pass which assigns WebAssembly register
+/// numbers for CodeGen virtual registers.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssembly.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "WebAssemblyMachineFunctionInfo.h"
+#include "WebAssemblySubtarget.h"
+#include "llvm/ADT/SCCIterator.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "wasm-reg-numbering"
+
+namespace {
+class WebAssemblyRegNumbering final : public MachineFunctionPass {
+  const char *getPassName() const override {
+    return "WebAssembly Register Numbering";
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesCFG();
+    MachineFunctionPass::getAnalysisUsage(AU);
+  }
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+public:
+  static char ID; // Pass identification, replacement for typeid
+  WebAssemblyRegNumbering() : MachineFunctionPass(ID) {}
+};
+} // end anonymous namespace
+
+char WebAssemblyRegNumbering::ID = 0;
+FunctionPass *llvm::createWebAssemblyRegNumbering() {
+  return new WebAssemblyRegNumbering();
+}
+
+bool WebAssemblyRegNumbering::runOnMachineFunction(MachineFunction &MF) {
+  DEBUG(dbgs() << "********** Register Numbering **********\n"
+                  "********** Function: "
+               << MF.getName() << '\n');
+
+  WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
+  MachineRegisterInfo &MRI = MF.getRegInfo();
+  const MachineFrameInfo &FrameInfo = *MF.getFrameInfo();
+
+  MFI.initWARegs();
+
+  // WebAssembly argument registers are in the same index space as local
+  // variables. Assign the numbers for them first.
+  MachineBasicBlock &EntryMBB = MF.front();
+  for (MachineInstr &MI : EntryMBB) {
+    switch (MI.getOpcode()) {
+    case WebAssembly::ARGUMENT_I32:
+    case WebAssembly::ARGUMENT_I64:
+    case WebAssembly::ARGUMENT_F32:
+    case WebAssembly::ARGUMENT_F64:
+      DEBUG(dbgs() << "Arg VReg " << MI.getOperand(0).getReg() << " -> WAReg "
+                   << MI.getOperand(1).getImm() << "\n");
+      MFI.setWAReg(MI.getOperand(0).getReg(), MI.getOperand(1).getImm());
+      break;
+    default:
+      break;
+    }
+  }
+
+  // Then assign regular WebAssembly registers for all remaining used
+  // virtual registers. TODO: Consider sorting the registers by frequency of
+  // use, to maximize usage of small immediate fields.
+  unsigned NumVRegs = MF.getRegInfo().getNumVirtRegs();
+  unsigned NumStackRegs = 0;
+  // Start the numbering for locals after the arg regs
+  unsigned CurReg = MFI.getParams().size();
+  for (unsigned VRegIdx = 0; VRegIdx < NumVRegs; ++VRegIdx) {
+    unsigned VReg = TargetRegisterInfo::index2VirtReg(VRegIdx);
+    // Skip unused registers.
+    if (MRI.use_empty(VReg))
+      continue;
+    // Handle stackified registers.
+    if (MFI.isVRegStackified(VReg)) {
+      DEBUG(dbgs() << "VReg " << VReg << " -> WAReg "
+                   << (INT32_MIN | NumStackRegs) << "\n");
+      MFI.setWAReg(VReg, INT32_MIN | NumStackRegs++);
+      continue;
+    }
+    if (MFI.getWAReg(VReg) == WebAssemblyFunctionInfo::UnusedReg) {
+      DEBUG(dbgs() << "VReg " << VReg << " -> WAReg " << CurReg << "\n");
+      MFI.setWAReg(VReg, CurReg++);
+    }
+  }
+  // Allocate locals for used physical registers
+  if (FrameInfo.getStackSize() > 0) {
+    DEBUG(dbgs() << "PReg SP " << CurReg << "\n");
+    MFI.addPReg(WebAssembly::SP32, CurReg++);
+  }
+
+  return true;
+}