#include "Support/Debug.h"
#include "Support/Statistic.h"
#include <iostream>
-
-namespace llvm {
+using namespace llvm;
namespace {
Statistic<> NumSpilled ("ra-local", "Number of registers spilled");
std::map<unsigned, int> StackSlotForVirtReg;
// Virt2PhysRegMap - This map contains entries for each virtual register
- // that is currently available in a physical register.
+ // that is currently available in a physical register. This is "logically"
+ // a map from virtual register numbers to physical register numbers.
+ // Instead of using a map, however, which is slow, we use a vector. The
+ // index is the VREG number - FirstVirtualRegister. If the entry is zero,
+ // then it is logically "not in the map".
//
- std::map<unsigned, unsigned> Virt2PhysRegMap;
+ std::vector<unsigned> Virt2PhysRegMap;
+
+ unsigned &getVirt2PhysRegMapSlot(unsigned VirtReg) {
+ assert(VirtReg >= MRegisterInfo::FirstVirtualRegister &&"Illegal VREG #");
+ assert(VirtReg-MRegisterInfo::FirstVirtualRegister <Virt2PhysRegMap.size()
+ && "VirtReg not in map!");
+ return Virt2PhysRegMap[VirtReg-MRegisterInfo::FirstVirtualRegister];
+ }
+ unsigned &getOrInsertVirt2PhysRegMapSlot(unsigned VirtReg) {
+ assert(VirtReg >= MRegisterInfo::FirstVirtualRegister &&"Illegal VREG #");
+ if (VirtReg-MRegisterInfo::FirstVirtualRegister >= Virt2PhysRegMap.size())
+ Virt2PhysRegMap.resize(VirtReg-MRegisterInfo::FirstVirtualRegister+1);
+ return Virt2PhysRegMap[VirtReg-MRegisterInfo::FirstVirtualRegister];
+ }
- // PhysRegsUsed - This map contains entries for each physical register that
- // currently has a value (ie, it is in Virt2PhysRegMap). The value mapped
- // to is the virtual register corresponding to the physical register (the
- // inverse of the Virt2PhysRegMap), or 0. The value is set to 0 if this
- // register is pinned because it is used by a future instruction.
+ // PhysRegsUsed - This array is effectively a map, containing entries for
+ // each physical register that currently has a value (ie, it is in
+ // Virt2PhysRegMap). The value mapped to is the virtual register
+ // corresponding to the physical register (the inverse of the
+ // Virt2PhysRegMap), or 0. The value is set to 0 if this register is pinned
+ // because it is used by a future instruction. If the entry for a physical
+ // register is -1, then the physical register is "not in the map".
//
- std::map<unsigned, unsigned> PhysRegsUsed;
+ int PhysRegsUsed[MRegisterInfo::FirstVirtualRegister];
// PhysRegsUseOrder - This contains a list of the physical registers that
// currently have a virtual register value in them. This list provides an
std::vector<bool> VirtRegModified;
void markVirtRegModified(unsigned Reg, bool Val = true) {
- assert(Reg >= MRegisterInfo::FirstVirtualRegister && "Illegal VirtReg!");
+ assert(MRegisterInfo::isVirtualRegister(Reg) && "Illegal VirtReg!");
Reg -= MRegisterInfo::FirstVirtualRegister;
if (VirtRegModified.size() <= Reg) VirtRegModified.resize(Reg+1);
VirtRegModified[Reg] = Val;
}
bool isVirtRegModified(unsigned Reg) const {
- assert(Reg >= MRegisterInfo::FirstVirtualRegister && "Illegal VirtReg!");
+ assert(MRegisterInfo::isVirtualRegister(Reg) && "Illegal VirtReg!");
assert(Reg - MRegisterInfo::FirstVirtualRegister < VirtRegModified.size()
&& "Illegal virtual register!");
return VirtRegModified[Reg - MRegisterInfo::FirstVirtualRegister];
/// longer being in use.
///
void RA::removePhysReg(unsigned PhysReg) {
- PhysRegsUsed.erase(PhysReg); // PhyReg no longer used
+ PhysRegsUsed[PhysReg] = -1; // PhyReg no longer used
std::vector<unsigned>::iterator It =
std::find(PhysRegsUseOrder.begin(), PhysRegsUseOrder.end(), PhysReg);
- assert(It != PhysRegsUseOrder.end() &&
- "Spilled a physical register, but it was not in use list!");
- PhysRegsUseOrder.erase(It);
+ if (It != PhysRegsUseOrder.end())
+ PhysRegsUseOrder.erase(It);
}
RegInfo->storeRegToStackSlot(MBB, I, PhysReg, FrameIndex, RC);
++NumSpilled; // Update statistics
}
- Virt2PhysRegMap.erase(VirtReg); // VirtReg no longer available
+
+ getVirt2PhysRegMapSlot(VirtReg) = 0; // VirtReg no longer available
DEBUG(std::cerr << "\n");
removePhysReg(PhysReg);
///
void RA::spillPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
unsigned PhysReg, bool OnlyVirtRegs) {
- std::map<unsigned, unsigned>::iterator PI = PhysRegsUsed.find(PhysReg);
- if (PI != PhysRegsUsed.end()) { // Only spill it if it's used!
- if (PI->second || !OnlyVirtRegs)
- spillVirtReg(MBB, I, PI->second, PhysReg);
+ if (PhysRegsUsed[PhysReg] != -1) { // Only spill it if it's used!
+ if (PhysRegsUsed[PhysReg] || !OnlyVirtRegs)
+ spillVirtReg(MBB, I, PhysRegsUsed[PhysReg], PhysReg);
} else {
// If the selected register aliases any other registers, we must make
// sure that one of the aliases isn't alive...
for (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg);
- *AliasSet; ++AliasSet) {
- PI = PhysRegsUsed.find(*AliasSet);
- if (PI != PhysRegsUsed.end()) // Spill aliased register...
- if (PI->second || !OnlyVirtRegs)
- spillVirtReg(MBB, I, PI->second, *AliasSet);
- }
+ *AliasSet; ++AliasSet)
+ if (PhysRegsUsed[*AliasSet] != -1) // Spill aliased register...
+ if (PhysRegsUsed[*AliasSet] || !OnlyVirtRegs)
+ spillVirtReg(MBB, I, PhysRegsUsed[*AliasSet], *AliasSet);
}
}
/// register must not be used for anything else when this is called.
///
void RA::assignVirtToPhysReg(unsigned VirtReg, unsigned PhysReg) {
- assert(PhysRegsUsed.find(PhysReg) == PhysRegsUsed.end() &&
- "Phys reg already assigned!");
+ assert(PhysRegsUsed[PhysReg] == -1 && "Phys reg already assigned!");
// Update information to note the fact that this register was just used, and
// it holds VirtReg.
PhysRegsUsed[PhysReg] = VirtReg;
- Virt2PhysRegMap[VirtReg] = PhysReg;
+ getOrInsertVirt2PhysRegMapSlot(VirtReg) = PhysReg;
PhysRegsUseOrder.push_back(PhysReg); // New use of PhysReg
}
/// registers are all free...
///
bool RA::isPhysRegAvailable(unsigned PhysReg) const {
- if (PhysRegsUsed.count(PhysReg)) return false;
+ if (PhysRegsUsed[PhysReg] != -1) return false;
// If the selected register aliases any other allocated registers, it is
// not free!
for (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg);
*AliasSet; ++AliasSet)
- if (PhysRegsUsed.count(*AliasSet)) // Aliased register in use?
+ if (PhysRegsUsed[*AliasSet] != -1) // Aliased register in use?
return false; // Can't use this reg then.
return true;
}
// Check to see if the register is directly used, not indirectly used through
// aliases. If aliased registers are the ones actually used, we cannot be
// sure that we will be able to save the whole thing if we do a reg-reg copy.
- std::map<unsigned, unsigned>::iterator PRUI = PhysRegsUsed.find(PhysReg);
- if (PRUI != PhysRegsUsed.end()) {
- unsigned VirtReg = PRUI->second; // The virtual register held...
+ if (PhysRegsUsed[PhysReg] != -1) {
+ // The virtual register held...
+ unsigned VirtReg = PhysRegsUsed[PhysReg]->second;
// Check to see if there is a compatible register available. If so, we can
// move the value into the new register...
// Update our internal state to indicate that PhysReg is available and Reg
// isn't.
- Virt2PhysRegMap.erase(VirtReg);
+ getVirt2PhysRegMapSlot[VirtReg] = 0;
removePhysReg(PhysReg); // Free the physreg
// Move reference over to new register...
// We can only use this register if it holds a virtual register (ie, it
// can be spilled). Do not use it if it is an explicitly allocated
// physical register!
- assert(PhysRegsUsed.count(R) &&
+ assert(PhysRegsUsed[R] != -1 &&
"PhysReg in PhysRegsUseOrder, but is not allocated?");
if (PhysRegsUsed[R]) {
// If the current register is compatible, use it.
unsigned RA::reloadVirtReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &I,
unsigned VirtReg) {
- std::map<unsigned, unsigned>::iterator It = Virt2PhysRegMap.find(VirtReg);
- if (It != Virt2PhysRegMap.end()) {
- MarkPhysRegRecentlyUsed(It->second);
- return It->second; // Already have this value available!
+ if (unsigned PR = getOrInsertVirt2PhysRegMapSlot(VirtReg)) {
+ MarkPhysRegRecentlyUsed(PR);
+ return PR; // Already have this value available!
}
unsigned PhysReg = getReg(MBB, I, VirtReg);
const TargetInstrDescriptor &TID = TM->getInstrInfo().get(MI->getOpcode());
DEBUG(std::cerr << "\nStarting RegAlloc of: " << *MI;
std::cerr << " Regs have values: ";
- for (std::map<unsigned, unsigned>::const_iterator
- I = PhysRegsUsed.begin(), E = PhysRegsUsed.end(); I != E; ++I)
- std::cerr << "[" << RegInfo->getName(I->first)
- << ",%reg" << I->second << "] ";
+ for (unsigned i = 0; i != RegInfo->getNumRegs(); ++i)
+ if (PhysRegsUsed[i] != -1)
+ std::cerr << "[" << RegInfo->getName(i)
+ << ",%reg" << PhysRegsUsed[i] << "] ";
std::cerr << "\n");
// Loop over the implicit uses, making sure that they are at the head of the
// use order list, so they don't get reallocated.
for (const unsigned *ImplicitUses = TID.ImplicitUses;
*ImplicitUses; ++ImplicitUses)
- MarkPhysRegRecentlyUsed(*ImplicitUses);
+ MarkPhysRegRecentlyUsed(*ImplicitUses);
// Get the used operands into registers. This has the potential to spill
// incoming values if we are out of registers. Note that we completely
KE = LV->killed_end(MI); KI != KE; ++KI) {
unsigned VirtReg = KI->second;
unsigned PhysReg = VirtReg;
- if (VirtReg >= MRegisterInfo::FirstVirtualRegister) {
- std::map<unsigned, unsigned>::iterator I =
- Virt2PhysRegMap.find(VirtReg);
- assert(I != Virt2PhysRegMap.end());
- PhysReg = I->second;
- Virt2PhysRegMap.erase(I);
+ if (MRegisterInfo::isVirtualRegister(VirtReg)) {
+ unsigned &PhysRegSlot = getVirt2PhysRegMapSlot(VirtReg);
+ PhysReg = PhysRegSlot;
+ assert(PhysReg != 0);
+ PhysRegSlot = 0;
}
if (PhysReg) {
// Loop over all of the operands of the instruction, spilling registers that
// are defined, and marking explicit destinations in the PhysRegsUsed map.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
- if (MI->getOperand(i).isDef() &&
- MI->getOperand(i).isPhysicalRegister()) {
+ if (MI->getOperand(i).isDef() && MI->getOperand(i).isRegister() &&
+ MRegisterInfo::isPhysicalRegister(MI->getOperand(i).getReg())) {
unsigned Reg = MI->getOperand(i).getAllocatedRegNum();
spillPhysReg(MBB, I, Reg, true); // Spill any existing value in the reg
PhysRegsUsed[Reg] = 0; // It is free and reserved now
PhysRegsUseOrder.push_back(Reg);
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+ *AliasSet; ++AliasSet) {
+ PhysRegsUseOrder.push_back(*AliasSet);
+ PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
+ }
}
// Loop over the implicit defs, spilling them as well.
spillPhysReg(MBB, I, Reg);
PhysRegsUseOrder.push_back(Reg);
PhysRegsUsed[Reg] = 0; // It is free and reserved now
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+ *AliasSet; ++AliasSet) {
+ PhysRegsUseOrder.push_back(*AliasSet);
+ PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
+ }
}
// Okay, we have allocated all of the source operands and spilled any values
unsigned DestPhysReg;
// If DestVirtReg already has a value, use it.
- std::map<unsigned, unsigned>::iterator DestI =
- Virt2PhysRegMap.find(DestVirtReg);
- if (DestI != Virt2PhysRegMap.end()) {
- DestPhysReg = DestI->second;
- }
- else {
+ if (!(DestPhysReg = getOrInsertVirt2PhysRegMapSlot(DestVirtReg)))
DestPhysReg = getReg(MBB, I, DestVirtReg);
- }
markVirtRegModified(DestVirtReg);
MI->SetMachineOperandReg(i, DestPhysReg); // Assign the output register
}
KE = LV->dead_end(MI); KI != KE; ++KI) {
unsigned VirtReg = KI->second;
unsigned PhysReg = VirtReg;
- if (VirtReg >= MRegisterInfo::FirstVirtualRegister) {
- std::map<unsigned, unsigned>::iterator I =
- Virt2PhysRegMap.find(VirtReg);
- assert(I != Virt2PhysRegMap.end());
- PhysReg = I->second;
- Virt2PhysRegMap.erase(I);
+ if (MRegisterInfo::isVirtualRegister(VirtReg)) {
+ unsigned &PhysRegSlot = getVirt2PhysRegMapSlot(VirtReg);
+ PhysReg = PhysRegSlot;
+ assert(PhysReg != 0);
+ PhysRegSlot = 0;
}
if (PhysReg) {
--I;
// Spill all physical registers holding virtual registers now.
- while (!PhysRegsUsed.empty())
- if (unsigned VirtReg = PhysRegsUsed.begin()->second)
- spillVirtReg(MBB, I, VirtReg, PhysRegsUsed.begin()->first);
- else
- removePhysReg(PhysRegsUsed.begin()->first);
-
- for (std::map<unsigned, unsigned>::iterator I = Virt2PhysRegMap.begin(),
- E = Virt2PhysRegMap.end(); I != E; ++I)
- std::cerr << "Register still mapped: " << I->first << " -> "
- << I->second << "\n";
-
- assert(Virt2PhysRegMap.empty() && "Virtual registers still in phys regs?");
+ for (unsigned i = 0, e = RegInfo->getNumRegs(); i != e; ++i)
+ if (PhysRegsUsed[i] != -1)
+ if (unsigned VirtReg = PhysRegsUsed[i])
+ spillVirtReg(MBB, I, VirtReg, i);
+ else
+ removePhysReg(i);
+
+#ifndef NDEBUG
+ bool AllOk = true;
+ for (unsigned i = 0, e = Virt2PhysRegMap.size(); i != e; ++i)
+ if (unsigned PR = Virt2PhysRegMap[i]) {
+ std::cerr << "Register still mapped: " << i << " -> " << PR << "\n";
+ AllOk = false;
+ }
+ assert(AllOk && "Virtual registers still in phys regs?");
+#endif
// Clear any physical register which appear live at the end of the basic
// block, but which do not hold any virtual registers. e.g., the stack
TM = &Fn.getTarget();
RegInfo = TM->getRegisterInfo();
+ memset(PhysRegsUsed, -1, RegInfo->getNumRegs()*sizeof(unsigned));
+
+ // Reserve some space for a moderate number of registers. If we know what the
+ // max virtual register number was we could use that instead and save some
+ // runtime overhead...
+ Virt2PhysRegMap.resize(1024);
+
if (!DisableKill)
LV = &getAnalysis<LiveVariables>();
StackSlotForVirtReg.clear();
VirtRegModified.clear();
+ Virt2PhysRegMap.clear();
return true;
}
-FunctionPass *createLocalRegisterAllocator() {
+FunctionPass *llvm::createLocalRegisterAllocator() {
return new RA();
}
-} // End llvm namespace
projects / oota-llvm.git / blobdiff