1 files changed, 97 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/LiveRegUnits.cpp b/llvm/lib/CodeGen/LiveRegUnits.cpp
new file mode 100644
index 00000000000..14da799a63f
--- /dev/null
+++ b/llvm/lib/CodeGen/LiveRegUnits.cpp
@@ -0,0 +1,97 @@
+//===--- LiveRegUnits.cpp - Register Unit Set -----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file This file imlements the LiveRegUnits set.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/LiveRegUnits.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBundle.h"
+using namespace llvm;
+
+void LiveRegUnits::removeRegsNotPreserved(const uint32_t *RegMask) {
+  for (unsigned U = 0, E = TRI->getNumRegUnits(); U != E; ++U) {
+    for (MCRegUnitRootIterator RootReg(U, TRI); RootReg.isValid(); ++RootReg) {
+      if (MachineOperand::clobbersPhysReg(RegMask, *RootReg))
+        Units.reset(U);
+    }
+  }
+}
+
+void LiveRegUnits::stepBackward(const MachineInstr &MI) {
+  // Remove defined registers and regmask kills from the set.
+  for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
+    if (O->isReg()) {
+      if (!O->isDef())
+        continue;
+      unsigned Reg = O->getReg();
+      if (!TargetRegisterInfo::isPhysicalRegister(Reg))
+        continue;
+      removeReg(Reg);
+    } else if (O->isRegMask())
+      removeRegsNotPreserved(O->getRegMask());
+  }
+
+  // Add uses to the set.
+  for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
+    if (!O->isReg() || !O->readsReg())
+      continue;
+    unsigned Reg = O->getReg();
+    if (!TargetRegisterInfo::isPhysicalRegister(Reg))
+      continue;
+    addReg(Reg);
+  }
+}
+
+/// Add live-in registers of basic block \p MBB to \p LiveUnits.
+static void addLiveIns(LiveRegUnits &LiveUnits, const MachineBasicBlock &MBB) {
+  for (const auto &LI : MBB.liveins())
+    LiveUnits.addRegMasked(LI.PhysReg, LI.LaneMask);
+}
+
+static void addLiveOuts(LiveRegUnits &LiveUnits, const MachineBasicBlock &MBB) {
+  // To get the live-outs we simply merge the live-ins of all successors.
+  for (const MachineBasicBlock *Succ : MBB.successors())
+    addLiveIns(LiveUnits, *Succ);
+}
+
+/// Add pristine registers to the given \p LiveUnits. This function removes
+/// actually saved callee save registers when \p InPrologueEpilogue is false.
+static void removeSavedRegs(LiveRegUnits &LiveUnits, const MachineFunction &MF,
+                            const MachineFrameInfo &MFI,
+                            const TargetRegisterInfo &TRI) {
+  for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
+    LiveUnits.removeReg(Info.getReg());
+}
+
+void LiveRegUnits::addLiveOuts(const MachineBasicBlock &MBB) {
+  const MachineFunction &MF = *MBB.getParent();
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  if (MFI.isCalleeSavedInfoValid()) {
+    for (const MCPhysReg *I = TRI->getCalleeSavedRegs(&MF); *I; ++I)
+      addReg(*I);
+    if (!MBB.isReturnBlock())
+      removeSavedRegs(*this, MF, MFI, *TRI);
+  }
+  ::addLiveOuts(*this, MBB);
+}
+
+void LiveRegUnits::addLiveIns(const MachineBasicBlock &MBB) {
+  const MachineFunction &MF = *MBB.getParent();
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  if (MFI.isCalleeSavedInfoValid()) {
+    for (const MCPhysReg *I = TRI->getCalleeSavedRegs(&MF); *I; ++I)
+      addReg(*I);
+    if (&MBB != &MF.front())
+      removeSavedRegs(*this, MF, MFI, *TRI);
+  }
+  ::addLiveIns(*this, MBB);
+}