#include "llvm/BasicBlock.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
class RAFast : public MachineFunctionPass {
public:
static char ID;
- RAFast() : MachineFunctionPass(&ID), StackSlotForVirtReg(-1),
- isBulkSpilling(false) {}
+ RAFast() : MachineFunctionPass(ID), StackSlotForVirtReg(-1),
+ isBulkSpilling(false) {
+ initializePHIEliminationPass(*PassRegistry::getPassRegistry());
+ initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
+ }
private:
const TargetMachine *TM;
MachineFunction *MF;
// that is currently available in a physical register.
LiveRegMap LiveVirtRegs;
+ DenseMap<unsigned, MachineInstr *> LiveDbgValueMap;
+
// RegState - Track the state of a physical register.
enum RegState {
// A disabled register is not available for allocation, but an alias may
// Allocatable - vector of allocatable physical registers.
BitVector Allocatable;
- // SkippedInstrs - Descriptors of instructions whose clobber list was ignored
- // because all registers were spilled. It is still necessary to mark all the
- // clobbered registers as used by the function.
+ // SkippedInstrs - Descriptors of instructions whose clobber list was
+ // ignored because all registers were spilled. It is still necessary to
+ // mark all the clobbered registers as used by the function.
SmallPtrSet<const TargetInstrDesc*, 4> SkippedInstrs;
// isBulkSpilling - This flag is set when LiveRegMap will be cleared
}
/// spillVirtReg - This method spills the value specified by VirtReg into the
-/// corresponding stack slot if needed. If isKill is set, the register is also
-/// killed.
+/// corresponding stack slot if needed.
void RAFast::spillVirtReg(MachineBasicBlock::iterator MI, unsigned VirtReg) {
assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
"Spilling a physical register is illegal!");
// instruction, not on the spill.
bool SpillKill = LR.LastUse != MI;
LR.Dirty = false;
- DEBUG(dbgs() << "Spilling %reg" << LRI->first
- << " in " << TRI->getName(LR.PhysReg));
+ DEBUG(dbgs() << "Spilling " << PrintReg(LRI->first, TRI)
+ << " in " << PrintReg(LR.PhysReg, TRI));
const TargetRegisterClass *RC = MRI->getRegClass(LRI->first);
int FI = getStackSpaceFor(LRI->first, RC);
DEBUG(dbgs() << " to stack slot #" << FI << "\n");
TII->storeRegToStackSlot(*MBB, MI, LR.PhysReg, SpillKill, FI, RC, TRI);
++NumStores; // Update statistics
+ // If this register is used by DBG_VALUE then insert new DBG_VALUE to
+ // identify spilled location as the place to find corresponding variable's
+ // value.
+ if (MachineInstr *DBG = LiveDbgValueMap.lookup(LRI->first)) {
+ const MDNode *MDPtr =
+ DBG->getOperand(DBG->getNumOperands()-1).getMetadata();
+ int64_t Offset = 0;
+ if (DBG->getOperand(1).isImm())
+ Offset = DBG->getOperand(1).getImm();
+ DebugLoc DL;
+ if (MI == MBB->end()) {
+ // If MI is at basic block end then use last instruction's location.
+ MachineBasicBlock::iterator EI = MI;
+ DL = (--EI)->getDebugLoc();
+ }
+ else
+ DL = MI->getDebugLoc();
+ if (MachineInstr *NewDV =
+ TII->emitFrameIndexDebugValue(*MF, FI, Offset, MDPtr, DL)) {
+ MachineBasicBlock *MBB = DBG->getParent();
+ MBB->insert(MI, NewDV);
+ DEBUG(dbgs() << "Inserting debug info due to spill:" << "\n" << *NewDV);
+ LiveDbgValueMap[LRI->first] = NewDV;
+ }
+ }
if (SpillKill)
LR.LastUse = 0; // Don't kill register again
}
MO.setIsKill();
return;
default:
- // The physreg was allocated to a virtual register. That means to value we
+ // The physreg was allocated to a virtual register. That means the value we
// wanted has been clobbered.
llvm_unreachable("Instruction uses an allocated register");
}
/// register must not be used for anything else when this is called.
///
void RAFast::assignVirtToPhysReg(LiveRegEntry &LRE, unsigned PhysReg) {
- DEBUG(dbgs() << "Assigning %reg" << LRE.first << " to "
- << TRI->getName(PhysReg) << "\n");
+ DEBUG(dbgs() << "Assigning " << PrintReg(LRE.first, TRI) << " to "
+ << PrintReg(PhysReg, TRI) << "\n");
PhysRegState[PhysReg] = LRE.first;
assert(!LRE.second.PhysReg && "Already assigned a physreg");
LRE.second.PhysReg = PhysReg;
// First try to find a completely free register.
for (TargetRegisterClass::iterator I = AOB; I != AOE; ++I) {
unsigned PhysReg = *I;
- if (PhysRegState[PhysReg] == regFree && !UsedInInstr.test(PhysReg))
+ if (PhysRegState[PhysReg] == regFree && !UsedInInstr.test(PhysReg) &&
+ Allocatable.test(PhysReg))
return assignVirtToPhysReg(LRE, PhysReg);
}
- DEBUG(dbgs() << "Allocating %reg" << VirtReg << " from " << RC->getName()
- << "\n");
+ DEBUG(dbgs() << "Allocating " << PrintReg(VirtReg) << " from "
+ << RC->getName() << "\n");
unsigned BestReg = 0, BestCost = spillImpossible;
for (TargetRegisterClass::iterator I = AOB; I != AOE; ++I) {
+ if (!Allocatable.test(*I))
+ continue;
unsigned Cost = calcSpillCost(*I);
// Cost is 0 when all aliases are already disabled.
if (Cost == 0)
allocVirtReg(MI, *LRI, Hint);
const TargetRegisterClass *RC = MRI->getRegClass(VirtReg);
int FrameIndex = getStackSpaceFor(VirtReg, RC);
- DEBUG(dbgs() << "Reloading %reg" << VirtReg << " into "
- << TRI->getName(LR.PhysReg) << "\n");
+ DEBUG(dbgs() << "Reloading " << PrintReg(VirtReg, TRI) << " into "
+ << PrintReg(LR.PhysReg, TRI) << "\n");
TII->loadRegFromStackSlot(*MBB, MI, LR.PhysReg, FrameIndex, RC, TRI);
++NumLoads;
} else if (LR.Dirty) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg()) continue;
unsigned Reg = MO.getReg();
- if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ if (!TargetRegisterInfo::isVirtualRegister(Reg))
+ continue;
if (MO.isEarlyClobber() || MI->isRegTiedToDefOperand(i) ||
(MO.getSubReg() && MI->readsVirtualRegister(Reg))) {
if (ThroughRegs.insert(Reg))
- DEBUG(dbgs() << " %reg" << Reg);
+ DEBUG(dbgs() << ' ' << PrintReg(Reg));
}
}
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg()) continue;
unsigned Reg = MO.getReg();
- if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ if (!TargetRegisterInfo::isVirtualRegister(Reg)) continue;
if (MO.isUse()) {
unsigned DefIdx = 0;
if (!MI->isRegTiedToDefOperand(i, &DefIdx)) continue;
void RAFast::AllocateBasicBlock() {
DEBUG(dbgs() << "\nAllocating " << *MBB);
+ // FIXME: This should probably be added by instruction selection instead?
+ // If the last instruction in the block is a return, make sure to mark it as
+ // using all of the live-out values in the function. Things marked both call
+ // and return are tail calls; do not do this for them. The tail callee need
+ // not take the same registers as input that it produces as output, and there
+ // are dependencies for its input registers elsewhere.
+ if (!MBB->empty() && MBB->back().getDesc().isReturn() &&
+ !MBB->back().getDesc().isCall()) {
+ MachineInstr *Ret = &MBB->back();
+
+ for (MachineRegisterInfo::liveout_iterator
+ I = MF->getRegInfo().liveout_begin(),
+ E = MF->getRegInfo().liveout_end(); I != E; ++I) {
+ assert(TargetRegisterInfo::isPhysicalRegister(*I) &&
+ "Cannot have a live-out virtual register.");
+
+ // Add live-out registers as implicit uses.
+ Ret->addRegisterKilled(*I, TRI, true);
+ }
+ }
+
PhysRegState.assign(TRI->getNumRegs(), regDisabled);
assert(LiveVirtRegs.empty() && "Mapping not cleared form last block?");
// Add live-in registers as live.
for (MachineBasicBlock::livein_iterator I = MBB->livein_begin(),
E = MBB->livein_end(); I != E; ++I)
- definePhysReg(MII, *I, regReserved);
+ if (Allocatable.test(*I))
+ definePhysReg(MII, *I, regReserved);
SmallVector<unsigned, 8> VirtDead;
SmallVector<MachineInstr*, 32> Coalesced;
dbgs() << "*";
break;
default:
- dbgs() << "=%reg" << PhysRegState[Reg];
+ dbgs() << '=' << PrintReg(PhysRegState[Reg]);
if (LiveVirtRegs[PhysRegState[Reg]].Dirty)
dbgs() << "*";
assert(LiveVirtRegs[PhysRegState[Reg]].PhysReg == Reg &&
// Debug values are not allowed to change codegen in any way.
if (MI->isDebugValue()) {
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg()) continue;
- unsigned Reg = MO.getReg();
- if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
- LiveRegMap::iterator LRI = LiveVirtRegs.find(Reg);
- if (LRI != LiveVirtRegs.end())
- setPhysReg(MI, i, LRI->second.PhysReg);
- else {
- int SS = StackSlotForVirtReg[Reg];
- if (SS == -1)
- MO.setReg(0); // We can't allocate a physreg for a DebugValue, sorry!
+ bool ScanDbgValue = true;
+ while (ScanDbgValue) {
+ ScanDbgValue = false;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg()) continue;
+ unsigned Reg = MO.getReg();
+ if (!TargetRegisterInfo::isVirtualRegister(Reg)) continue;
+ LiveDbgValueMap[Reg] = MI;
+ LiveRegMap::iterator LRI = LiveVirtRegs.find(Reg);
+ if (LRI != LiveVirtRegs.end())
+ setPhysReg(MI, i, LRI->second.PhysReg);
else {
- // Modify DBG_VALUE now that the value is in a spill slot.
- uint64_t Offset = MI->getOperand(1).getImm();
- const MDNode *MDPtr =
- MI->getOperand(MI->getNumOperands()-1).getMetadata();
- DebugLoc DL = MI->getDebugLoc();
- if (MachineInstr *NewDV =
- TII->emitFrameIndexDebugValue(*MF, SS, Offset, MDPtr, DL)) {
- DEBUG(dbgs() << "Modifying debug info due to spill:" << "\t" << *MI);
- MachineBasicBlock *MBB = MI->getParent();
- MBB->insert(MBB->erase(MI), NewDV);
- } else
- MO.setReg(0); // We can't allocate a physreg for a DebugValue, sorry!
+ int SS = StackSlotForVirtReg[Reg];
+ if (SS == -1) {
+ // We can't allocate a physreg for a DebugValue, sorry!
+ DEBUG(dbgs() << "Unable to allocate vreg used by DBG_VALUE");
+ MO.setReg(0);
+ }
+ else {
+ // Modify DBG_VALUE now that the value is in a spill slot.
+ int64_t Offset = MI->getOperand(1).getImm();
+ const MDNode *MDPtr =
+ MI->getOperand(MI->getNumOperands()-1).getMetadata();
+ DebugLoc DL = MI->getDebugLoc();
+ if (MachineInstr *NewDV =
+ TII->emitFrameIndexDebugValue(*MF, SS, Offset, MDPtr, DL)) {
+ DEBUG(dbgs() << "Modifying debug info due to spill:" <<
+ "\t" << *MI);
+ MachineBasicBlock *MBB = MI->getParent();
+ MBB->insert(MBB->erase(MI), NewDV);
+ // Scan NewDV operands from the beginning.
+ MI = NewDV;
+ ScanDbgValue = true;
+ break;
+ } else {
+ // We can't allocate a physreg for a DebugValue; sorry!
+ DEBUG(dbgs() << "Unable to allocate vreg used by DBG_VALUE");
+ MO.setReg(0);
+ }
+ }
}
}
}
// operands. If there are also physical defs, these registers must avoid
// both physical defs and uses, making them more constrained than normal
// operands.
+ // Similarly, if there are multiple defs and tied operands, we must make
+ // sure the same register is allocated to uses and defs.
// We didn't detect inline asm tied operands above, so just make this extra
// pass for all inline asm.
if (MI->isInlineAsm() || hasEarlyClobbers || hasPartialRedefs ||
- (hasTiedOps && hasPhysDefs)) {
+ (hasTiedOps && (hasPhysDefs || TID.getNumDefs() > 1))) {
handleThroughOperands(MI, VirtDead);
// Don't attempt coalescing when we have funny stuff going on.
CopyDst = 0;
+ // Pretend we have early clobbers so the use operands get marked below.
+ // This is not necessary for the common case of a single tied use.
+ hasEarlyClobbers = true;
}
// Second scan.
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg()) continue;
unsigned Reg = MO.getReg();
- if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ if (!TargetRegisterInfo::isVirtualRegister(Reg)) continue;
if (MO.isUse()) {
LiveRegMap::iterator LRI = reloadVirtReg(MI, i, Reg, CopyDst);
unsigned PhysReg = LRI->second.PhysReg;
MRI->addPhysRegsUsed(UsedInInstr);
- // Track registers defined by instruction - early clobbers at this point.
+ // Track registers defined by instruction - early clobbers and tied uses at
+ // this point.
UsedInInstr.reset();
if (hasEarlyClobbers) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.isDef()) continue;
+ if (!MO.isReg()) continue;
unsigned Reg = MO.getReg();
if (!Reg || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ // Look for physreg defs and tied uses.
+ if (!MO.isDef() && !MI->isRegTiedToDefOperand(i)) continue;
UsedInInstr.set(Reg);
for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
UsedInInstr.set(*AS);
unsigned DefOpEnd = MI->getNumOperands();
if (TID.isCall()) {
// Spill all virtregs before a call. This serves two purposes: 1. If an
- // exception is thrown, the landing pad is going to expect to find registers
- // in their spill slots, and 2. we don't have to wade through all the
- // <imp-def> operands on the call instruction.
+ // exception is thrown, the landing pad is going to expect to find
+ // registers in their spill slots, and 2. we don't have to wade through
+ // all the <imp-def> operands on the call instruction.
DefOpEnd = VirtOpEnd;
DEBUG(dbgs() << " Spilling remaining registers before call.\n");
spillAll(MI);
// initialize the virtual->physical register map to have a 'null'
// mapping for all virtual registers
- unsigned LastVirtReg = MRI->getLastVirtReg();
- StackSlotForVirtReg.grow(LastVirtReg);
+ StackSlotForVirtReg.resize(MRI->getNumVirtRegs());
// Loop over all of the basic blocks, eliminating virtual register references
for (MachineFunction::iterator MBBi = Fn.begin(), MBBe = Fn.end();
SkippedInstrs.clear();
StackSlotForVirtReg.clear();
+ LiveDbgValueMap.clear();
return true;
}
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