ARMConstantIslandPass.cpp [plain text]
#define DEBUG_TYPE "arm-cp-islands"
#include "ARM.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMInstrInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumCPEs, "Number of constpool entries");
STATISTIC(NumSplit, "Number of uncond branches inserted");
STATISTIC(NumCBrFixed, "Number of cond branches fixed");
STATISTIC(NumUBrFixed, "Number of uncond branches fixed");
namespace {
class VISIBILITY_HIDDEN ARMConstantIslands : public MachineFunctionPass {
std::vector<unsigned> BBSizes;
std::vector<unsigned> BBOffsets;
std::vector<MachineBasicBlock*> WaterList;
struct CPUser {
MachineInstr *MI;
MachineInstr *CPEMI;
unsigned MaxDisp;
CPUser(MachineInstr *mi, MachineInstr *cpemi, unsigned maxdisp)
: MI(mi), CPEMI(cpemi), MaxDisp(maxdisp) {}
};
std::vector<CPUser> CPUsers;
struct CPEntry {
MachineInstr *CPEMI;
unsigned CPI;
unsigned RefCount;
CPEntry(MachineInstr *cpemi, unsigned cpi, unsigned rc = 0)
: CPEMI(cpemi), CPI(cpi), RefCount(rc) {}
};
std::vector<std::vector<CPEntry> > CPEntries;
struct ImmBranch {
MachineInstr *MI;
unsigned MaxDisp : 31;
bool isCond : 1;
int UncondBr;
ImmBranch(MachineInstr *mi, unsigned maxdisp, bool cond, int ubr)
: MI(mi), MaxDisp(maxdisp), isCond(cond), UncondBr(ubr) {}
};
std::vector<ImmBranch> ImmBranches;
SmallVector<MachineInstr*, 4> PushPopMIs;
bool HasFarJump;
const TargetInstrInfo *TII;
ARMFunctionInfo *AFI;
bool isThumb;
public:
static char ID;
ARMConstantIslands() : MachineFunctionPass(&ID) {}
virtual bool runOnMachineFunction(MachineFunction &Fn);
virtual const char *getPassName() const {
return "ARM constant island placement and branch shortening pass";
}
private:
void DoInitialPlacement(MachineFunction &Fn,
std::vector<MachineInstr*> &CPEMIs);
CPEntry *findConstPoolEntry(unsigned CPI, const MachineInstr *CPEMI);
void InitialFunctionScan(MachineFunction &Fn,
const std::vector<MachineInstr*> &CPEMIs);
MachineBasicBlock *SplitBlockBeforeInstr(MachineInstr *MI);
void UpdateForInsertedWaterBlock(MachineBasicBlock *NewBB);
void AdjustBBOffsetsAfter(MachineBasicBlock *BB, int delta);
bool DecrementOldEntry(unsigned CPI, MachineInstr* CPEMI);
int LookForExistingCPEntry(CPUser& U, unsigned UserOffset);
bool LookForWater(CPUser&U, unsigned UserOffset,
MachineBasicBlock** NewMBB);
MachineBasicBlock* AcceptWater(MachineBasicBlock *WaterBB,
std::vector<MachineBasicBlock*>::iterator IP);
void CreateNewWater(unsigned CPUserIndex, unsigned UserOffset,
MachineBasicBlock** NewMBB);
bool HandleConstantPoolUser(MachineFunction &Fn, unsigned CPUserIndex);
void RemoveDeadCPEMI(MachineInstr *CPEMI);
bool RemoveUnusedCPEntries();
bool CPEIsInRange(MachineInstr *MI, unsigned UserOffset,
MachineInstr *CPEMI, unsigned Disp,
bool DoDump);
bool WaterIsInRange(unsigned UserOffset, MachineBasicBlock *Water,
CPUser &U);
bool OffsetIsInRange(unsigned UserOffset, unsigned TrialOffset,
unsigned Disp, bool NegativeOK);
bool BBIsInRange(MachineInstr *MI, MachineBasicBlock *BB, unsigned Disp);
bool FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br);
bool FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br);
bool FixUpUnconditionalBr(MachineFunction &Fn, ImmBranch &Br);
bool UndoLRSpillRestore();
unsigned GetOffsetOf(MachineInstr *MI) const;
void dumpBBs();
void verify(MachineFunction &Fn);
};
char ARMConstantIslands::ID = 0;
}
void ARMConstantIslands::verify(MachineFunction &Fn) {
assert(BBOffsets.size() == BBSizes.size());
for (unsigned i = 1, e = BBOffsets.size(); i != e; ++i)
assert(BBOffsets[i-1]+BBSizes[i-1] == BBOffsets[i]);
if (isThumb) {
for (MachineFunction::iterator MBBI = Fn.begin(), E = Fn.end();
MBBI != E; ++MBBI) {
MachineBasicBlock *MBB = MBBI;
if (!MBB->empty() &&
MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
assert((BBOffsets[MBB->getNumber()]%4 == 0 &&
BBSizes[MBB->getNumber()]%4 == 0) ||
(BBOffsets[MBB->getNumber()]%4 != 0 &&
BBSizes[MBB->getNumber()]%4 != 0));
}
}
}
void ARMConstantIslands::dumpBBs() {
for (unsigned J = 0, E = BBOffsets.size(); J !=E; ++J) {
DOUT << "block " << J << " offset " << BBOffsets[J] <<
" size " << BBSizes[J] << "\n";
}
}
FunctionPass *llvm::createARMConstantIslandPass() {
return new ARMConstantIslands();
}
bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
MachineConstantPool &MCP = *Fn.getConstantPool();
TII = Fn.getTarget().getInstrInfo();
AFI = Fn.getInfo<ARMFunctionInfo>();
isThumb = AFI->isThumbFunction();
HasFarJump = false;
Fn.RenumberBlocks();
AFI->setAlign(isThumb ? 1U : 2U);
std::vector<MachineInstr*> CPEMIs;
if (!MCP.isEmpty()) {
DoInitialPlacement(Fn, CPEMIs);
if (isThumb)
AFI->setAlign(2U);
}
AFI->initConstPoolEntryUId(CPEMIs.size());
InitialFunctionScan(Fn, CPEMIs);
CPEMIs.clear();
RemoveUnusedCPEntries();
bool MadeChange = false;
while (true) {
bool Change = false;
for (unsigned i = 0, e = CPUsers.size(); i != e; ++i)
Change |= HandleConstantPoolUser(Fn, i);
DEBUG(dumpBBs());
for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
Change |= FixUpImmediateBr(Fn, ImmBranches[i]);
DEBUG(dumpBBs());
if (!Change)
break;
MadeChange = true;
}
verify(Fn);
if (!HasFarJump && AFI->isLRSpilledForFarJump() && isThumb)
MadeChange |= UndoLRSpillRestore();
BBSizes.clear();
BBOffsets.clear();
WaterList.clear();
CPUsers.clear();
CPEntries.clear();
ImmBranches.clear();
PushPopMIs.clear();
return MadeChange;
}
void ARMConstantIslands::DoInitialPlacement(MachineFunction &Fn,
std::vector<MachineInstr*> &CPEMIs){
MachineBasicBlock *BB = Fn.CreateMachineBasicBlock();
Fn.push_back(BB);
const std::vector<MachineConstantPoolEntry> &CPs =
Fn.getConstantPool()->getConstants();
const TargetData &TD = *Fn.getTarget().getTargetData();
for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
unsigned Size = TD.getTypePaddedSize(CPs[i].getType());
assert((Size & 3) == 0 && "CP Entry not multiple of 4 bytes!");
MachineInstr *CPEMI =
BuildMI(BB, DebugLoc::getUnknownLoc(), TII->get(ARM::CONSTPOOL_ENTRY))
.addImm(i).addConstantPoolIndex(i).addImm(Size);
CPEMIs.push_back(CPEMI);
std::vector<CPEntry> CPEs;
CPEs.push_back(CPEntry(CPEMI, i));
CPEntries.push_back(CPEs);
NumCPEs++;
DOUT << "Moved CPI#" << i << " to end of function as #" << i << "\n";
}
}
static bool BBHasFallthrough(MachineBasicBlock *MBB) {
MachineFunction::iterator MBBI = MBB;
if (next(MBBI) == MBB->getParent()->end()) return false;
MachineBasicBlock *NextBB = next(MBBI);
for (MachineBasicBlock::succ_iterator I = MBB->succ_begin(),
E = MBB->succ_end(); I != E; ++I)
if (*I == NextBB)
return true;
return false;
}
ARMConstantIslands::CPEntry
*ARMConstantIslands::findConstPoolEntry(unsigned CPI,
const MachineInstr *CPEMI) {
std::vector<CPEntry> &CPEs = CPEntries[CPI];
for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
if (CPEs[i].CPEMI == CPEMI)
return &CPEs[i];
}
return NULL;
}
void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
const std::vector<MachineInstr*> &CPEMIs) {
unsigned Offset = 0;
for (MachineFunction::iterator MBBI = Fn.begin(), E = Fn.end();
MBBI != E; ++MBBI) {
MachineBasicBlock &MBB = *MBBI;
if (!BBHasFallthrough(&MBB))
WaterList.push_back(&MBB);
unsigned MBBSize = 0;
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
I != E; ++I) {
MBBSize += TII->GetInstSizeInBytes(I);
int Opc = I->getOpcode();
if (I->getDesc().isBranch()) {
bool isCond = false;
unsigned Bits = 0;
unsigned Scale = 1;
int UOpc = Opc;
switch (Opc) {
case ARM::tBR_JTr:
AFI->setAlign(2U);
if ((Offset+MBBSize)%4 != 0)
MBBSize += 2; continue; default:
continue; case ARM::Bcc:
isCond = true;
UOpc = ARM::B;
case ARM::B:
Bits = 24;
Scale = 4;
break;
case ARM::tBcc:
isCond = true;
UOpc = ARM::tB;
Bits = 8;
Scale = 2;
break;
case ARM::tB:
Bits = 11;
Scale = 2;
break;
}
unsigned MaxOffs = ((1 << (Bits-1))-1) * Scale;
ImmBranches.push_back(ImmBranch(I, MaxOffs, isCond, UOpc));
}
if (Opc == ARM::tPUSH || Opc == ARM::tPOP_RET)
PushPopMIs.push_back(I);
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
if (I->getOperand(op).isCPI()) {
unsigned Bits = 0;
unsigned Scale = 1;
unsigned TSFlags = I->getDesc().TSFlags;
switch (TSFlags & ARMII::AddrModeMask) {
default:
if (I->getOpcode() == ARM::CONSTPOOL_ENTRY)
continue;
if (I->getOpcode() == ARM::tLEApcrel) {
Bits = 8; break;
}
assert(0 && "Unknown addressing mode for CP reference!");
case ARMII::AddrMode1: Bits = 8;
Scale = 4; break;
case ARMII::AddrMode2:
Bits = 12; break;
case ARMII::AddrMode3:
Bits = 8; break;
case ARMII::AddrMode5:
Bits = 8;
Scale = 4; break;
case ARMII::AddrModeT1:
Bits = 5; break;
case ARMII::AddrModeT2:
Bits = 5;
Scale = 2; break;
case ARMII::AddrModeT4:
Bits = 5;
Scale = 4; break;
case ARMII::AddrModeTs:
Bits = 8;
Scale = 4; break;
}
unsigned CPI = I->getOperand(op).getIndex();
MachineInstr *CPEMI = CPEMIs[CPI];
unsigned MaxOffs = ((1 << Bits)-1) * Scale;
CPUsers.push_back(CPUser(I, CPEMI, MaxOffs));
CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
assert(CPE && "Cannot find a corresponding CPEntry!");
CPE->RefCount++;
break;
}
}
if (isThumb &&
!MBB.empty() &&
MBB.begin()->getOpcode() == ARM::CONSTPOOL_ENTRY &&
(Offset%4) != 0)
MBBSize += 2;
BBSizes.push_back(MBBSize);
BBOffsets.push_back(Offset);
Offset += MBBSize;
}
}
unsigned ARMConstantIslands::GetOffsetOf(MachineInstr *MI) const {
MachineBasicBlock *MBB = MI->getParent();
unsigned Offset = BBOffsets[MBB->getNumber()];
if (isThumb &&
MI->getOpcode() == ARM::CONSTPOOL_ENTRY &&
Offset%4 != 0)
Offset += 2;
for (MachineBasicBlock::iterator I = MBB->begin(); ; ++I) {
assert(I != MBB->end() && "Didn't find MI in its own basic block?");
if (&*I == MI) return Offset;
Offset += TII->GetInstSizeInBytes(I);
}
}
static bool CompareMBBNumbers(const MachineBasicBlock *LHS,
const MachineBasicBlock *RHS) {
return LHS->getNumber() < RHS->getNumber();
}
void ARMConstantIslands::UpdateForInsertedWaterBlock(MachineBasicBlock *NewBB) {
NewBB->getParent()->RenumberBlocks(NewBB);
BBSizes.insert(BBSizes.begin()+NewBB->getNumber(), 0);
BBOffsets.insert(BBOffsets.begin()+NewBB->getNumber(), 0);
std::vector<MachineBasicBlock*>::iterator IP =
std::lower_bound(WaterList.begin(), WaterList.end(), NewBB,
CompareMBBNumbers);
WaterList.insert(IP, NewBB);
}
MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
MachineBasicBlock *OrigBB = MI->getParent();
MachineFunction &MF = *OrigBB->getParent();
MachineBasicBlock *NewBB = MF.CreateMachineBasicBlock(OrigBB->getBasicBlock());
MachineFunction::iterator MBBI = OrigBB; ++MBBI;
MF.insert(MBBI, NewBB);
NewBB->splice(NewBB->end(), OrigBB, MI, OrigBB->end());
BuildMI(OrigBB, DebugLoc::getUnknownLoc(),
TII->get(isThumb ? ARM::tB : ARM::B)).addMBB(NewBB);
NumSplit++;
while (!OrigBB->succ_empty()) {
MachineBasicBlock *Succ = *OrigBB->succ_begin();
OrigBB->removeSuccessor(Succ);
NewBB->addSuccessor(Succ);
assert((Succ->empty() || Succ->begin()->getOpcode() != TargetInstrInfo::PHI)
&& "PHI nodes should be eliminated by now!");
}
OrigBB->addSuccessor(NewBB);
MF.RenumberBlocks(NewBB);
BBSizes.insert(BBSizes.begin()+NewBB->getNumber(), 0);
BBOffsets.insert(BBOffsets.begin()+NewBB->getNumber(), 0);
std::vector<MachineBasicBlock*>::iterator IP =
std::lower_bound(WaterList.begin(), WaterList.end(), OrigBB,
CompareMBBNumbers);
MachineBasicBlock* WaterBB = *IP;
if (WaterBB == OrigBB)
WaterList.insert(next(IP), NewBB);
else
WaterList.insert(IP, OrigBB);
unsigned NewBBSize = 0;
for (MachineBasicBlock::iterator I = NewBB->begin(), E = NewBB->end();
I != E; ++I)
NewBBSize += TII->GetInstSizeInBytes(I);
unsigned OrigBBI = OrigBB->getNumber();
unsigned NewBBI = NewBB->getNumber();
BBSizes[NewBBI] = NewBBSize;
unsigned delta = isThumb ? 2 : 4;
BBSizes[OrigBBI] -= NewBBSize - delta;
BBOffsets[NewBBI] = BBOffsets[OrigBBI] + BBSizes[OrigBBI];
AdjustBBOffsetsAfter(NewBB, delta);
return NewBB;
}
bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
unsigned TrialOffset, unsigned MaxDisp, bool NegativeOK) {
if (isThumb && UserOffset%4 !=0)
UserOffset -= 2;
if (isThumb && TrialOffset%4 != 0)
TrialOffset += 2;
if (UserOffset <= TrialOffset) {
if (TrialOffset-UserOffset <= MaxDisp)
return true;
} else if (NegativeOK) {
if (UserOffset-TrialOffset <= MaxDisp)
return true;
}
return false;
}
bool ARMConstantIslands::WaterIsInRange(unsigned UserOffset,
MachineBasicBlock* Water, CPUser &U)
{
unsigned MaxDisp = U.MaxDisp;
MachineFunction::iterator I = next(MachineFunction::iterator(Water));
unsigned CPEOffset = BBOffsets[Water->getNumber()] +
BBSizes[Water->getNumber()];
if (CPEOffset < UserOffset)
UserOffset += U.CPEMI->getOperand(2).getImm();
return OffsetIsInRange (UserOffset, CPEOffset, MaxDisp, !isThumb);
}
bool ARMConstantIslands::CPEIsInRange(MachineInstr *MI, unsigned UserOffset,
MachineInstr *CPEMI,
unsigned MaxDisp, bool DoDump) {
unsigned CPEOffset = GetOffsetOf(CPEMI);
assert(CPEOffset%4 == 0 && "Misaligned CPE");
if (DoDump) {
DOUT << "User of CPE#" << CPEMI->getOperand(0).getImm()
<< " max delta=" << MaxDisp
<< " insn address=" << UserOffset
<< " CPE address=" << CPEOffset
<< " offset=" << int(CPEOffset-UserOffset) << "\t" << *MI;
}
return OffsetIsInRange(UserOffset, CPEOffset, MaxDisp, !isThumb);
}
#ifndef NDEBUG
static bool BBIsJumpedOver(MachineBasicBlock *MBB) {
if (MBB->pred_size() != 1 || MBB->succ_size() != 1)
return false;
MachineBasicBlock *Succ = *MBB->succ_begin();
MachineBasicBlock *Pred = *MBB->pred_begin();
MachineInstr *PredMI = &Pred->back();
if (PredMI->getOpcode() == ARM::B || PredMI->getOpcode() == ARM::tB)
return PredMI->getOperand(0).getMBB() == Succ;
return false;
}
#endif // NDEBUG
void ARMConstantIslands::AdjustBBOffsetsAfter(MachineBasicBlock *BB,
int delta) {
MachineFunction::iterator MBBI = BB; MBBI = next(MBBI);
for(unsigned i=BB->getNumber()+1; i<BB->getParent()->getNumBlockIDs(); i++) {
BBOffsets[i] += delta;
if (isThumb) {
MachineBasicBlock *MBB = MBBI;
if (!MBB->empty()) {
if (MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY) {
unsigned oldOffset = BBOffsets[i] - delta;
if (oldOffset%4==0 && BBOffsets[i]%4!=0) {
BBSizes[i] += 2;
delta += 2;
} else if (oldOffset%4!=0 && BBOffsets[i]%4==0) {
BBSizes[i] -=2;
delta -= 2;
}
}
MachineInstr *ThumbJTMI = NULL;
if (prior(MBB->end())->getOpcode() == ARM::tBR_JTr)
ThumbJTMI = prior(MBB->end());
if (ThumbJTMI) {
unsigned newMIOffset = GetOffsetOf(ThumbJTMI);
unsigned oldMIOffset = newMIOffset - delta;
if (oldMIOffset%4 == 0 && newMIOffset%4 != 0) {
BBSizes[i] -= 2;
delta -= 2;
} else if (oldMIOffset%4 != 0 && newMIOffset%4 == 0) {
BBSizes[i] += 2;
delta += 2;
}
}
if (delta==0)
return;
}
MBBI = next(MBBI);
}
}
}
bool ARMConstantIslands::DecrementOldEntry(unsigned CPI, MachineInstr *CPEMI) {
CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
assert(CPE && "Unexpected!");
if (--CPE->RefCount == 0) {
RemoveDeadCPEMI(CPEMI);
CPE->CPEMI = NULL;
NumCPEs--;
return true;
}
return false;
}
int ARMConstantIslands::LookForExistingCPEntry(CPUser& U, unsigned UserOffset)
{
MachineInstr *UserMI = U.MI;
MachineInstr *CPEMI = U.CPEMI;
if (CPEIsInRange(UserMI, UserOffset, CPEMI, U.MaxDisp, true)) {
DOUT << "In range\n";
return 1;
}
unsigned CPI = CPEMI->getOperand(1).getIndex();
std::vector<CPEntry> &CPEs = CPEntries[CPI];
for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
if (CPEs[i].CPEMI == CPEMI)
continue;
if (CPEs[i].CPEMI == NULL)
continue;
if (CPEIsInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.MaxDisp, false)) {
DOUT << "Replacing CPE#" << CPI << " with CPE#" << CPEs[i].CPI << "\n";
U.CPEMI = CPEs[i].CPEMI;
for (unsigned j = 0, e = UserMI->getNumOperands(); j != e; ++j)
if (UserMI->getOperand(j).isCPI()) {
UserMI->getOperand(j).setIndex(CPEs[i].CPI);
break;
}
CPEs[i].RefCount++;
return DecrementOldEntry(CPI, CPEMI) ? 2 : 1;
}
}
return 0;
}
static inline unsigned getUnconditionalBrDisp(int Opc) {
return (Opc == ARM::tB) ? ((1<<10)-1)*2 : ((1<<23)-1)*4;
}
MachineBasicBlock* ARMConstantIslands::AcceptWater(MachineBasicBlock *WaterBB,
std::vector<MachineBasicBlock*>::iterator IP) {
DOUT << "found water in range\n";
WaterList.erase(IP);
return next(MachineFunction::iterator(WaterBB));
}
bool ARMConstantIslands::LookForWater(CPUser &U, unsigned UserOffset,
MachineBasicBlock** NewMBB) {
std::vector<MachineBasicBlock*>::iterator IPThatWouldPad;
MachineBasicBlock* WaterBBThatWouldPad = NULL;
if (!WaterList.empty()) {
for (std::vector<MachineBasicBlock*>::iterator IP = prior(WaterList.end()),
B = WaterList.begin();; --IP) {
MachineBasicBlock* WaterBB = *IP;
if (WaterIsInRange(UserOffset, WaterBB, U)) {
if (isThumb &&
(BBOffsets[WaterBB->getNumber()] +
BBSizes[WaterBB->getNumber()])%4 != 0) {
if (!WaterBBThatWouldPad) {
WaterBBThatWouldPad = WaterBB;
IPThatWouldPad = IP;
}
} else {
*NewMBB = AcceptWater(WaterBB, IP);
return true;
}
}
if (IP == B)
break;
}
}
if (isThumb && WaterBBThatWouldPad) {
*NewMBB = AcceptWater(WaterBBThatWouldPad, IPThatWouldPad);
return true;
}
return false;
}
void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
unsigned UserOffset, MachineBasicBlock** NewMBB) {
CPUser &U = CPUsers[CPUserIndex];
MachineInstr *UserMI = U.MI;
MachineInstr *CPEMI = U.CPEMI;
MachineBasicBlock *UserMBB = UserMI->getParent();
unsigned OffsetOfNextBlock = BBOffsets[UserMBB->getNumber()] +
BBSizes[UserMBB->getNumber()];
assert(OffsetOfNextBlock== BBOffsets[UserMBB->getNumber()+1]);
if (&UserMBB->back() == UserMI ||
OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb ? 2: 4),
U.MaxDisp, !isThumb)) {
DOUT << "Split at end of block\n";
if (&UserMBB->back() == UserMI)
assert(BBHasFallthrough(UserMBB) && "Expected a fallthrough BB!");
*NewMBB = next(MachineFunction::iterator(UserMBB));
int UncondBr = isThumb ? ARM::tB : ARM::B;
BuildMI(UserMBB, DebugLoc::getUnknownLoc(),
TII->get(UncondBr)).addMBB(*NewMBB);
unsigned MaxDisp = getUnconditionalBrDisp(UncondBr);
ImmBranches.push_back(ImmBranch(&UserMBB->back(),
MaxDisp, false, UncondBr));
int delta = isThumb ? 2 : 4;
BBSizes[UserMBB->getNumber()] += delta;
AdjustBBOffsetsAfter(UserMBB, delta);
} else {
unsigned BaseInsertOffset = UserOffset + U.MaxDisp -4;
if (BaseInsertOffset >= BBOffsets[UserMBB->getNumber()+1])
BaseInsertOffset = BBOffsets[UserMBB->getNumber()+1] -
(isThumb ? 6 : 8);
unsigned EndInsertOffset = BaseInsertOffset +
CPEMI->getOperand(2).getImm();
MachineBasicBlock::iterator MI = UserMI;
++MI;
unsigned CPUIndex = CPUserIndex+1;
for (unsigned Offset = UserOffset+TII->GetInstSizeInBytes(UserMI);
Offset < BaseInsertOffset;
Offset += TII->GetInstSizeInBytes(MI),
MI = next(MI)) {
if (CPUIndex < CPUsers.size() && CPUsers[CPUIndex].MI == MI) {
if (!OffsetIsInRange(Offset, EndInsertOffset,
CPUsers[CPUIndex].MaxDisp, !isThumb)) {
BaseInsertOffset -= (isThumb ? 2 : 4);
EndInsertOffset -= (isThumb ? 2 : 4);
}
EndInsertOffset += CPUsers[CPUIndex].CPEMI->getOperand(2).getImm();
CPUIndex++;
}
}
DOUT << "Split in middle of big block\n";
*NewMBB = SplitBlockBeforeInstr(prior(MI));
}
}
bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
unsigned CPUserIndex){
CPUser &U = CPUsers[CPUserIndex];
MachineInstr *UserMI = U.MI;
MachineInstr *CPEMI = U.CPEMI;
unsigned CPI = CPEMI->getOperand(1).getIndex();
unsigned Size = CPEMI->getOperand(2).getImm();
MachineBasicBlock *NewMBB;
unsigned UserOffset = GetOffsetOf(UserMI) + (isThumb ? 4 : 8);
if (UserMI->getOpcode() == ARM::tLEApcrel)
UserOffset += 2;
int result = LookForExistingCPEntry(U, UserOffset);
if (result==1) return false;
else if (result==2) return true;
unsigned ID = AFI->createConstPoolEntryUId();
if (!LookForWater(U, UserOffset, &NewMBB)) {
DOUT << "No water found\n";
CreateNewWater(CPUserIndex, UserOffset, &NewMBB);
}
MachineBasicBlock *NewIsland = Fn.CreateMachineBasicBlock();
Fn.insert(NewMBB, NewIsland);
UpdateForInsertedWaterBlock(NewIsland);
DecrementOldEntry(CPI, CPEMI);
U.CPEMI = BuildMI(NewIsland, DebugLoc::getUnknownLoc(),
TII->get(ARM::CONSTPOOL_ENTRY))
.addImm(ID).addConstantPoolIndex(CPI).addImm(Size);
CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
NumCPEs++;
BBOffsets[NewIsland->getNumber()] = BBOffsets[NewMBB->getNumber()];
if (isThumb && BBOffsets[NewIsland->getNumber()]%4 != 0)
Size += 2;
BBSizes[NewIsland->getNumber()] += Size;
AdjustBBOffsetsAfter(NewIsland, Size);
for (unsigned i = 0, e = UserMI->getNumOperands(); i != e; ++i)
if (UserMI->getOperand(i).isCPI()) {
UserMI->getOperand(i).setIndex(ID);
break;
}
DOUT << " Moved CPE to #" << ID << " CPI=" << CPI << "\t" << *UserMI;
return true;
}
void ARMConstantIslands::RemoveDeadCPEMI(MachineInstr *CPEMI) {
MachineBasicBlock *CPEBB = CPEMI->getParent();
unsigned Size = CPEMI->getOperand(2).getImm();
CPEMI->eraseFromParent();
BBSizes[CPEBB->getNumber()] -= Size;
if (CPEBB->empty()) {
if (BBSizes[CPEBB->getNumber()] != 0) {
Size += BBSizes[CPEBB->getNumber()];
BBSizes[CPEBB->getNumber()] = 0;
}
}
AdjustBBOffsetsAfter(CPEBB, -Size);
assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
}
bool ARMConstantIslands::RemoveUnusedCPEntries() {
unsigned MadeChange = false;
for (unsigned i = 0, e = CPEntries.size(); i != e; ++i) {
std::vector<CPEntry> &CPEs = CPEntries[i];
for (unsigned j = 0, ee = CPEs.size(); j != ee; ++j) {
if (CPEs[j].RefCount == 0 && CPEs[j].CPEMI) {
RemoveDeadCPEMI(CPEs[j].CPEMI);
CPEs[j].CPEMI = NULL;
MadeChange = true;
}
}
}
return MadeChange;
}
bool ARMConstantIslands::BBIsInRange(MachineInstr *MI,MachineBasicBlock *DestBB,
unsigned MaxDisp) {
unsigned PCAdj = isThumb ? 4 : 8;
unsigned BrOffset = GetOffsetOf(MI) + PCAdj;
unsigned DestOffset = BBOffsets[DestBB->getNumber()];
DOUT << "Branch of destination BB#" << DestBB->getNumber()
<< " from BB#" << MI->getParent()->getNumber()
<< " max delta=" << MaxDisp
<< " from " << GetOffsetOf(MI) << " to " << DestOffset
<< " offset " << int(DestOffset-BrOffset) << "\t" << *MI;
if (BrOffset <= DestOffset) {
if (DestOffset-BrOffset <= MaxDisp)
return true;
} else {
if (BrOffset-DestOffset <= MaxDisp)
return true;
}
return false;
}
bool ARMConstantIslands::FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
if (BBIsInRange(MI, DestBB, Br.MaxDisp))
return false;
if (!Br.isCond)
return FixUpUnconditionalBr(Fn, Br);
return FixUpConditionalBr(Fn, Br);
}
bool
ARMConstantIslands::FixUpUnconditionalBr(MachineFunction &Fn, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
MachineBasicBlock *MBB = MI->getParent();
assert(isThumb && "Expected a Thumb function!");
Br.MaxDisp = (1 << 21) * 2;
MI->setDesc(TII->get(ARM::tBfar));
BBSizes[MBB->getNumber()] += 2;
AdjustBBOffsetsAfter(MBB, 2);
HasFarJump = true;
NumUBrFixed++;
DOUT << " Changed B to long jump " << *MI;
return true;
}
bool
ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
ARMCC::CondCodes CC = (ARMCC::CondCodes)MI->getOperand(1).getImm();
CC = ARMCC::getOppositeCondition(CC);
unsigned CCReg = MI->getOperand(2).getReg();
MachineBasicBlock *MBB = MI->getParent();
MachineInstr *BMI = &MBB->back();
bool NeedSplit = (BMI != MI) || !BBHasFallthrough(MBB);
NumCBrFixed++;
if (BMI != MI) {
if (next(MachineBasicBlock::iterator(MI)) == prior(MBB->end()) &&
BMI->getOpcode() == Br.UncondBr) {
MachineBasicBlock *NewDest = BMI->getOperand(0).getMBB();
if (BBIsInRange(MI, NewDest, Br.MaxDisp)) {
DOUT << " Invert Bcc condition and swap its destination with " << *BMI;
BMI->getOperand(0).setMBB(DestBB);
MI->getOperand(0).setMBB(NewDest);
MI->getOperand(1).setImm(CC);
return true;
}
}
}
if (NeedSplit) {
SplitBlockBeforeInstr(MI);
int delta = TII->GetInstSizeInBytes(&MBB->back());
BBSizes[MBB->getNumber()] -= delta;
MachineBasicBlock* SplitBB = next(MachineFunction::iterator(MBB));
AdjustBBOffsetsAfter(SplitBB, -delta);
MBB->back().eraseFromParent();
}
MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
DOUT << " Insert B to BB#" << DestBB->getNumber()
<< " also invert condition and change dest. to BB#"
<< NextBB->getNumber() << "\n";
BuildMI(MBB, DebugLoc::getUnknownLoc(),
TII->get(MI->getOpcode()))
.addMBB(NextBB).addImm(CC).addReg(CCReg);
Br.MI = &MBB->back();
BBSizes[MBB->getNumber()] += TII->GetInstSizeInBytes(&MBB->back());
BuildMI(MBB, DebugLoc::getUnknownLoc(), TII->get(Br.UncondBr)).addMBB(DestBB);
BBSizes[MBB->getNumber()] += TII->GetInstSizeInBytes(&MBB->back());
unsigned MaxDisp = getUnconditionalBrDisp(Br.UncondBr);
ImmBranches.push_back(ImmBranch(&MBB->back(), MaxDisp, false, Br.UncondBr));
BBSizes[MI->getParent()->getNumber()] -= TII->GetInstSizeInBytes(MI);
MI->eraseFromParent();
int delta = TII->GetInstSizeInBytes(&MBB->back());
AdjustBBOffsetsAfter(MBB, delta);
return true;
}
bool ARMConstantIslands::UndoLRSpillRestore() {
bool MadeChange = false;
for (unsigned i = 0, e = PushPopMIs.size(); i != e; ++i) {
MachineInstr *MI = PushPopMIs[i];
if (MI->getOpcode() == ARM::tPOP_RET &&
MI->getOperand(0).getReg() == ARM::PC &&
MI->getNumExplicitOperands() == 1) {
BuildMI(MI->getParent(), MI->getDebugLoc(), TII->get(ARM::tBX_RET));
MI->eraseFromParent();
MadeChange = true;
}
}
return MadeChange;
}