1 //===- LiveRegUnits.cpp - Register Unit Set -------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 /// \file This file imlements the LiveRegUnits set.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/LiveRegUnits.h"
16 #include "llvm/CodeGen/MachineBasicBlock.h"
17 #include "llvm/CodeGen/MachineFrameInfo.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/MachineInstrBundle.h"
20 #include "llvm/CodeGen/MachineOperand.h"
21 #include "llvm/CodeGen/MachineRegisterInfo.h"
22 #include "llvm/MC/MCRegisterInfo.h"
23 #include "llvm/Target/TargetRegisterInfo.h"
27 void LiveRegUnits::removeRegsNotPreserved(const uint32_t *RegMask) {
28 for (unsigned U = 0, E = TRI->getNumRegUnits(); U != E; ++U) {
29 for (MCRegUnitRootIterator RootReg(U, TRI); RootReg.isValid(); ++RootReg) {
30 if (MachineOperand::clobbersPhysReg(RegMask, *RootReg))
36 void LiveRegUnits::addRegsInMask(const uint32_t *RegMask) {
37 for (unsigned U = 0, E = TRI->getNumRegUnits(); U != E; ++U) {
38 for (MCRegUnitRootIterator RootReg(U, TRI); RootReg.isValid(); ++RootReg) {
39 if (MachineOperand::clobbersPhysReg(RegMask, *RootReg))
45 void LiveRegUnits::stepBackward(const MachineInstr &MI) {
46 // Remove defined registers and regmask kills from the set.
47 for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
51 unsigned Reg = O->getReg();
52 if (!TargetRegisterInfo::isPhysicalRegister(Reg))
55 } else if (O->isRegMask())
56 removeRegsNotPreserved(O->getRegMask());
59 // Add uses to the set.
60 for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
61 if (!O->isReg() || !O->readsReg())
63 unsigned Reg = O->getReg();
64 if (!TargetRegisterInfo::isPhysicalRegister(Reg))
70 void LiveRegUnits::accumulate(const MachineInstr &MI) {
71 // Add defs, uses and regmask clobbers to the set.
72 for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
74 unsigned Reg = O->getReg();
75 if (!TargetRegisterInfo::isPhysicalRegister(Reg))
77 if (!O->isDef() && !O->readsReg())
80 } else if (O->isRegMask())
81 addRegsInMask(O->getRegMask());
85 /// Add live-in registers of basic block \p MBB to \p LiveUnits.
86 static void addBlockLiveIns(LiveRegUnits &LiveUnits,
87 const MachineBasicBlock &MBB) {
88 for (const auto &LI : MBB.liveins())
89 LiveUnits.addRegMasked(LI.PhysReg, LI.LaneMask);
92 /// Adds all callee saved registers to \p LiveUnits.
93 static void addCalleeSavedRegs(LiveRegUnits &LiveUnits,
94 const MachineFunction &MF) {
95 const MachineRegisterInfo &MRI = MF.getRegInfo();
96 for (const MCPhysReg *CSR = MRI.getCalleeSavedRegs(); CSR && *CSR; ++CSR)
97 LiveUnits.addReg(*CSR);
100 /// Adds pristine registers to the given \p LiveUnits. Pristine registers are
101 /// callee saved registers that are unused in the function.
102 static void addPristines(LiveRegUnits &LiveUnits, const MachineFunction &MF) {
103 const MachineFrameInfo &MFI = MF.getFrameInfo();
104 if (!MFI.isCalleeSavedInfoValid())
106 /// Add all callee saved regs, then remove the ones that are saved+restored.
107 addCalleeSavedRegs(LiveUnits, MF);
108 /// Remove the ones that are not saved/restored; they are pristine.
109 for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
110 LiveUnits.removeReg(Info.getReg());
113 void LiveRegUnits::addLiveOuts(const MachineBasicBlock &MBB) {
114 const MachineFunction &MF = *MBB.getParent();
115 if (!MBB.succ_empty()) {
116 addPristines(*this, MF);
117 // To get the live-outs we simply merge the live-ins of all successors.
118 for (const MachineBasicBlock *Succ : MBB.successors())
119 addBlockLiveIns(*this, *Succ);
120 } else if (MBB.isReturnBlock()) {
121 // For the return block: Add all callee saved registers.
122 const MachineFrameInfo &MFI = MF.getFrameInfo();
123 if (MFI.isCalleeSavedInfoValid())
124 addCalleeSavedRegs(*this, MF);
128 void LiveRegUnits::addLiveIns(const MachineBasicBlock &MBB) {
129 const MachineFunction &MF = *MBB.getParent();
130 addPristines(*this, MF);
131 addBlockLiveIns(*this, MBB);