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//===-- lib/Codegen/MachineRegisterInfo.cpp -------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Implementation of the MachineRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineRegisterInfo.h"
using namespace llvm;
MachineRegisterInfo::MachineRegisterInfo(const TargetRegisterInfo &TRI) {
VRegInfo.reserve(256);
RegAllocHints.reserve(256);
RegClass2VRegMap.resize(TRI.getNumRegClasses()+1); // RC ID starts at 1.
UsedPhysRegs.resize(TRI.getNumRegs());
// Create the physreg use/def lists.
PhysRegUseDefLists = new MachineOperand*[TRI.getNumRegs()];
memset(PhysRegUseDefLists, 0, sizeof(MachineOperand*)*TRI.getNumRegs());
}
MachineRegisterInfo::~MachineRegisterInfo() {
#ifndef NDEBUG
for (unsigned i = 0, e = VRegInfo.size(); i != e; ++i)
assert(VRegInfo[i].second == 0 && "Vreg use list non-empty still?");
for (unsigned i = 0, e = UsedPhysRegs.size(); i != e; ++i)
assert(!PhysRegUseDefLists[i] &&
"PhysRegUseDefLists has entries after all instructions are deleted");
#endif
delete [] PhysRegUseDefLists;
}
/// setRegClass - Set the register class of the specified virtual register.
///
void
MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) {
unsigned VR = Reg;
Reg -= TargetRegisterInfo::FirstVirtualRegister;
assert(Reg < VRegInfo.size() && "Invalid vreg!");
const TargetRegisterClass *OldRC = VRegInfo[Reg].first;
VRegInfo[Reg].first = RC;
// Remove from old register class's vregs list. This may be slow but
// fortunately this operation is rarely needed.
std::vector<unsigned> &VRegs = RegClass2VRegMap[OldRC->getID()];
std::vector<unsigned>::iterator I=std::find(VRegs.begin(), VRegs.end(), VR);
VRegs.erase(I);
// Add to new register class's vregs list.
RegClass2VRegMap[RC->getID()].push_back(VR);
}
/// createVirtualRegister - Create and return a new virtual register in the
/// function with the specified register class.
///
unsigned
MachineRegisterInfo::createVirtualRegister(const TargetRegisterClass *RegClass){
assert(RegClass && "Cannot create register without RegClass!");
// Add a reg, but keep track of whether the vector reallocated or not.
void *ArrayBase = VRegInfo.empty() ? 0 : &VRegInfo[0];
VRegInfo.push_back(std::make_pair(RegClass, (MachineOperand*)0));
RegAllocHints.push_back(std::make_pair(0, 0));
if (!((&VRegInfo[0] == ArrayBase || VRegInfo.size() == 1)))
// The vector reallocated, handle this now.
HandleVRegListReallocation();
unsigned VR = getLastVirtReg();
RegClass2VRegMap[RegClass->getID()].push_back(VR);
return VR;
}
/// HandleVRegListReallocation - We just added a virtual register to the
/// VRegInfo info list and it reallocated. Update the use/def lists info
/// pointers.
void MachineRegisterInfo::HandleVRegListReallocation() {
// The back pointers for the vreg lists point into the previous vector.
// Update them to point to their correct slots.
for (unsigned i = 0, e = VRegInfo.size(); i != e; ++i) {
MachineOperand *List = VRegInfo[i].second;
if (!List) continue;
// Update the back-pointer to be accurate once more.
List->Contents.Reg.Prev = &VRegInfo[i].second;
}
}
/// replaceRegWith - Replace all instances of FromReg with ToReg in the
/// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
/// except that it also changes any definitions of the register as well.
void MachineRegisterInfo::replaceRegWith(unsigned FromReg, unsigned ToReg) {
assert(FromReg != ToReg && "Cannot replace a reg with itself");
// TODO: This could be more efficient by bulk changing the operands.
for (reg_iterator I = reg_begin(FromReg), E = reg_end(); I != E; ) {
MachineOperand &O = I.getOperand();
++I;
O.setReg(ToReg);
}
}
/// getVRegDef - Return the machine instr that defines the specified virtual
/// register or null if none is found. This assumes that the code is in SSA
/// form, so there should only be one definition.
MachineInstr *MachineRegisterInfo::getVRegDef(unsigned Reg) const {
assert(Reg-TargetRegisterInfo::FirstVirtualRegister < VRegInfo.size() &&
"Invalid vreg!");
// Since we are in SSA form, we can use the first definition.
if (!def_empty(Reg))
return &*def_begin(Reg);
return 0;
}
bool MachineRegisterInfo::hasOneUse(unsigned RegNo) const {
use_iterator UI = use_begin(RegNo);
if (UI == use_end())
return false;
return ++UI == use_end();
}
bool MachineRegisterInfo::hasOneNonDBGUse(unsigned RegNo) const {
use_nodbg_iterator UI = use_nodbg_begin(RegNo);
if (UI == use_nodbg_end())
return false;
return ++UI == use_nodbg_end();
}
#ifndef NDEBUG
void MachineRegisterInfo::dumpUses(unsigned Reg) const {
for (use_iterator I = use_begin(Reg), E = use_end(); I != E; ++I)
I.getOperand().getParent()->dump();
}
#endif
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