llvm/lib/CodeGen/LiveRegUnits.cpp

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//===--- 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::addRegsInMask(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.set(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);
}
}
void LiveRegUnits::accumulateBackward(const MachineInstr &MI) {
// Add defs, uses and regmask clobbers to the set.
for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
if (O->isReg()) {
unsigned Reg = O->getReg();
if (!TargetRegisterInfo::isPhysicalRegister(Reg))
continue;
if (!O->isDef() && !O->readsReg())
continue;
addReg(Reg);
} else if (O->isRegMask())
addRegsInMask(O->getRegMask());
}
}
/// 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);
}