//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Chris Lattner and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// CPE - A constant pool entry that has been placed somewhere, which
/// tracks a list of users.
class VISIBILITY_HIDDEN ARMConstantIslands : public MachineFunctionPass {
- /// NextUID - Assign unique ID's to CPE's.
- unsigned NextUID;
-
/// BBSizes - The size of each MachineBasicBlock in bytes of code, indexed
- /// by MBB Number.
+ /// by MBB Number. The two-byte pads required for Thumb alignment are
+ /// counted as part of the following block (i.e., the offset and size for
+ /// a padded block will both be ==2 mod 4).
std::vector<unsigned> BBSizes;
/// BBOffsets - the offset of each MBB in bytes, starting from 0.
+ /// The two-byte pads required for Thumb alignment are counted as part of
+ /// the following block.
std::vector<unsigned> BBOffsets;
/// WaterList - A sorted list of basic blocks where islands could be placed
: MI(mi), MaxDisp(maxdisp), isCond(cond), UncondBr(ubr) {}
};
- /// Branches - Keep track of all the immediate branch instructions.
+ /// ImmBranches - Keep track of all the immediate branch instructions.
///
std::vector<ImmBranch> ImmBranches;
bool HasFarJump;
const TargetInstrInfo *TII;
- const ARMFunctionInfo *AFI;
+ ARMFunctionInfo *AFI;
bool isThumb;
public:
+ static char ID;
+ ARMConstantIslands() : MachineFunctionPass(&ID) {}
+
virtual bool runOnMachineFunction(MachineFunction &Fn);
virtual const char *getPassName() const {
void AdjustBBOffsetsAfter(MachineBasicBlock *BB, int delta);
bool DecrementOldEntry(unsigned CPI, MachineInstr* CPEMI);
int LookForExistingCPEntry(CPUser& U, unsigned UserOffset);
- bool LookForWater(CPUser&U, unsigned UserOffset, bool* PadNewWater,
+ 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);
MachineInstr *CPEMI, unsigned Disp,
bool DoDump);
bool WaterIsInRange(unsigned UserOffset, MachineBasicBlock *Water,
- unsigned Disp);
+ CPUser &U);
bool OffsetIsInRange(unsigned UserOffset, unsigned TrialOffset,
unsigned Disp, bool NegativeOK);
bool BBIsInRange(MachineInstr *MI, MachineBasicBlock *BB, unsigned Disp);
bool UndoLRSpillRestore();
unsigned GetOffsetOf(MachineInstr *MI) const;
+ void dumpBBs();
+ void verify(MachineFunction &Fn);
};
+ char ARMConstantIslands::ID = 0;
+}
+
+/// verify - check BBOffsets, BBSizes, alignment of islands
+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));
+ }
+ }
+}
+
+/// print block size and offset information - debugging
+void ARMConstantIslands::dumpBBs() {
+ for (unsigned J = 0, E = BBOffsets.size(); J !=E; ++J) {
+ DOUT << "block " << J << " offset " << BBOffsets[J] <<
+ " size " << BBSizes[J] << "\n";
+ }
}
/// createARMConstantIslandPass - returns an instance of the constpool
// the numbers agree with the position of the block in the function.
Fn.RenumberBlocks();
+ /// Thumb functions containing constant pools get 2-byte alignment. This is so
+ /// we can keep exact track of where the alignment padding goes. Set default.
+ AFI->setAlign(isThumb ? 1U : 2U);
+
// Perform the initial placement of the constant pool entries. To start with,
// we put them all at the end of the function.
std::vector<MachineInstr*> CPEMIs;
- if (!MCP.isEmpty())
+ if (!MCP.isEmpty()) {
DoInitialPlacement(Fn, CPEMIs);
+ if (isThumb)
+ AFI->setAlign(2U);
+ }
/// The next UID to take is the first unused one.
- NextUID = CPEMIs.size();
+ AFI->initConstPoolEntryUId(CPEMIs.size());
// Do the initial scan of the function, building up information about the
// sizes of each block, the location of all the water, and finding all of the
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;
}
+ // After a while, this might be made debug-only, but it is not expensive.
+ verify(Fn);
+
// If LR has been forced spilled and no far jumps (i.e. BL) has been issued.
// Undo the spill / restore of LR if possible.
if (!HasFarJump && AFI->isLRSpilledForFarJump() && isThumb)
void ARMConstantIslands::DoInitialPlacement(MachineFunction &Fn,
std::vector<MachineInstr*> &CPEMIs){
// Create the basic block to hold the CPE's.
- MachineBasicBlock *BB = new MachineBasicBlock();
- Fn.getBasicBlockList().push_back(BB);
+ MachineBasicBlock *BB = Fn.CreateMachineBasicBlock();
+ Fn.push_back(BB);
// Add all of the constants from the constant pool to the end block, use an
// identity mapping of CPI's to CPE's.
const TargetData &TD = *Fn.getTarget().getTargetData();
for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
- unsigned Size = TD.getTypeSize(CPs[i].getType());
+ unsigned Size = TD.getABITypeSize(CPs[i].getType());
// Verify that all constant pool entries are a multiple of 4 bytes. If not,
// we would have to pad them out or something so that instructions stay
// aligned.
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
I != E; ++I) {
// Add instruction size to MBBSize.
- MBBSize += ARM::GetInstSize(I);
+ MBBSize += TII->GetInstSizeInBytes(I);
int Opc = I->getOpcode();
- if (TII->isBranch(Opc)) {
+ if (I->getDesc().isBranch()) {
bool isCond = false;
unsigned Bits = 0;
unsigned Scale = 1;
int UOpc = Opc;
switch (Opc) {
+ case ARM::tBR_JTr:
+ // A Thumb table jump may involve padding; for the offsets to
+ // be right, functions containing these must be 4-byte aligned.
+ AFI->setAlign(2U);
+ if ((Offset+MBBSize)%4 != 0)
+ MBBSize += 2; // padding
+ continue; // Does not get an entry in ImmBranches
default:
- continue; // Ignore JT branches
+ continue; // Ignore other JT branches
case ARM::Bcc:
isCond = true;
UOpc = ARM::B;
// Scan the instructions for constant pool operands.
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
- if (I->getOperand(op).isConstantPoolIndex()) {
+ if (I->getOperand(op).isCPI()) {
// We found one. The addressing mode tells us the max displacement
// from the PC that this instruction permits.
// Basic size info comes from the TSFlags field.
unsigned Bits = 0;
unsigned Scale = 1;
- unsigned TSFlags = I->getInstrDescriptor()->TSFlags;
+ unsigned TSFlags = I->getDesc().TSFlags;
switch (TSFlags & ARMII::AddrModeMask) {
default:
// Constant pool entries can reach anything.
if (I->getOpcode() == ARM::CONSTPOOL_ENTRY)
continue;
+ if (I->getOpcode() == ARM::tLEApcrel) {
+ Bits = 8; // Taking the address of a CP entry.
+ break;
+ }
assert(0 && "Unknown addressing mode for CP reference!");
case ARMII::AddrMode1: // AM1: 8 bits << 2
Bits = 8;
}
// Remember that this is a user of a CP entry.
- unsigned CPI = I->getOperand(op).getConstantPoolIndex();
+ unsigned CPI = I->getOperand(op).getIndex();
MachineInstr *CPEMI = CPEMIs[CPI];
unsigned MaxOffs = ((1 << Bits)-1) * Scale;
CPUsers.push_back(CPUser(I, CPEMI, MaxOffs));
}
}
- // In thumb mode, if this block is a constpool island, pessimistically
- // assume it needs to be padded by two byte so it's aligned on 4 byte
- // boundary.
+ // In thumb mode, if this block is a constpool island, we may need padding
+ // so it's aligned on 4 byte boundary.
if (isThumb &&
!MBB.empty() &&
- MBB.begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
+ MBB.begin()->getOpcode() == ARM::CONSTPOOL_ENTRY &&
+ (Offset%4) != 0)
MBBSize += 2;
BBSizes.push_back(MBBSize);
// it is in.
unsigned Offset = BBOffsets[MBB->getNumber()];
+ // If we're looking for a CONSTPOOL_ENTRY in Thumb, see if this block has
+ // alignment padding, and compensate if so.
+ if (isThumb &&
+ MI->getOpcode() == ARM::CONSTPOOL_ENTRY &&
+ Offset%4 != 0)
+ Offset += 2;
+
// Sum instructions before MI in MBB.
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 += ARM::GetInstSize(I);
+ Offset += TII->GetInstSizeInBytes(I);
}
}
/// account for this change and returns the newly created block.
MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
MachineBasicBlock *OrigBB = MI->getParent();
+ MachineFunction &MF = *OrigBB->getParent();
// Create a new MBB for the code after the OrigBB.
- MachineBasicBlock *NewBB = new MachineBasicBlock(OrigBB->getBasicBlock());
+ MachineBasicBlock *NewBB = MF.CreateMachineBasicBlock(OrigBB->getBasicBlock());
MachineFunction::iterator MBBI = OrigBB; ++MBBI;
- OrigBB->getParent()->getBasicBlockList().insert(MBBI, NewBB);
+ MF.insert(MBBI, NewBB);
// Splice the instructions starting with MI over to NewBB.
NewBB->splice(NewBB->end(), OrigBB, MI, OrigBB->end());
// Update internal data structures to account for the newly inserted MBB.
// This is almost the same as UpdateForInsertedWaterBlock, except that
// the Water goes after OrigBB, not NewBB.
- NewBB->getParent()->RenumberBlocks(NewBB);
+ MF.RenumberBlocks(NewBB);
// Insert a size into BBSizes to align it properly with the (newly
// renumbered) block numbers.
else
WaterList.insert(IP, OrigBB);
- // Figure out how large the first NewMBB is.
+ // Figure out how large the first NewMBB is. (It cannot
+ // contain a constpool_entry or tablejump.)
unsigned NewBBSize = 0;
for (MachineBasicBlock::iterator I = NewBB->begin(), E = NewBB->end();
I != E; ++I)
- NewBBSize += ARM::GetInstSize(I);
+ NewBBSize += TII->GetInstSizeInBytes(I);
unsigned OrigBBI = OrigBB->getNumber();
unsigned NewBBI = NewBB->getNumber();
return NewBB;
}
-/// OffsetIsInRange - Checks whether UserOffset is within MaxDisp of
-/// TrialOffset.
+/// OffsetIsInRange - Checks whether UserOffset (the location of a constant pool
+/// reference) is within MaxDisp of TrialOffset (a proposed location of a
+/// constant pool entry).
bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
unsigned TrialOffset, unsigned MaxDisp, bool NegativeOK) {
+ // On Thumb offsets==2 mod 4 are rounded down by the hardware for
+ // purposes of the displacement computation; compensate for that here.
+ // Effectively, the valid range of displacements is 2 bytes smaller for such
+ // references.
+ if (isThumb && UserOffset%4 !=0)
+ UserOffset -= 2;
+ // CPEs will be rounded up to a multiple of 4.
+ if (isThumb && TrialOffset%4 != 0)
+ TrialOffset += 2;
+
if (UserOffset <= TrialOffset) {
// User before the Trial.
if (TrialOffset-UserOffset <= MaxDisp)
/// Water (a basic block) will be in range for the specific MI.
bool ARMConstantIslands::WaterIsInRange(unsigned UserOffset,
- MachineBasicBlock* Water, unsigned MaxDisp)
+ MachineBasicBlock* Water, CPUser &U)
{
+ unsigned MaxDisp = U.MaxDisp;
+ MachineFunction::iterator I = next(MachineFunction::iterator(Water));
unsigned CPEOffset = BBOffsets[Water->getNumber()] +
BBSizes[Water->getNumber()];
- // If the Water is a constpool island, it has already been aligned.
- // If not, align it.
- if (isThumb &&
- (Water->empty() ||
- Water->begin()->getOpcode() != ARM::CONSTPOOL_ENTRY))
- CPEOffset += 2;
// If the CPE is to be inserted before the instruction, that will raise
- // the offset of the instruction.
+ // the offset of the instruction. (Currently applies only to ARM, so
+ // no alignment compensation attempted here.)
if (CPEOffset < UserOffset)
- UserOffset += isThumb ? 2 : 4;
+ 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) {
- // In thumb mode, pessimistically assumes the .align 2 before the first CPE
- // in the island adds two byte padding.
- unsigned AlignAdj = isThumb ? 2 : 0;
- unsigned CPEOffset = GetOffsetOf(CPEMI) + AlignAdj;
+ unsigned CPEOffset = GetOffsetOf(CPEMI);
+ assert(CPEOffset%4 == 0 && "Misaligned CPE");
if (DoDump) {
DOUT << "User of CPE#" << CPEMI->getOperand(0).getImm()
return false;
}
-void ARMConstantIslands::AdjustBBOffsetsAfter(MachineBasicBlock *BB, int delta)
-{
- MachineFunction::iterator MBBI = BB->getParent()->end();
- for(unsigned i=BB->getNumber()+1; i<BB->getParent()->getNumBlockIDs(); i++)
+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 some existing blocks have padding, adjust the padding as needed, a
+ // bit tricky. delta can be negative so don't use % on that.
+ if (isThumb) {
+ MachineBasicBlock *MBB = MBBI;
+ if (!MBB->empty()) {
+ // Constant pool entries require padding.
+ if (MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY) {
+ unsigned oldOffset = BBOffsets[i] - delta;
+ if (oldOffset%4==0 && BBOffsets[i]%4!=0) {
+ // add new padding
+ BBSizes[i] += 2;
+ delta += 2;
+ } else if (oldOffset%4!=0 && BBOffsets[i]%4==0) {
+ // remove existing padding
+ BBSizes[i] -=2;
+ delta -= 2;
+ }
+ }
+ // Thumb jump tables require padding. They should be at the end;
+ // following unconditional branches are removed by AnalyzeBranch.
+ 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) {
+ // remove existing padding
+ BBSizes[i] -= 2;
+ delta -= 2;
+ } else if (oldMIOffset%4 != 0 && newMIOffset%4 == 0) {
+ // add new padding
+ BBSizes[i] += 2;
+ delta += 2;
+ }
+ }
+ if (delta==0)
+ return;
+ }
+ MBBI = next(MBBI);
+ }
+ }
}
/// DecrementOldEntry - find the constant pool entry with index CPI
}
// No. Look for previously created clones of the CPE that are in range.
- unsigned CPI = CPEMI->getOperand(1).getConstantPoolIndex();
+ unsigned CPI = CPEMI->getOperand(1).getIndex();
std::vector<CPEntry> &CPEs = CPEntries[CPI];
for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
// We already tried this one
U.CPEMI = CPEs[i].CPEMI;
// Change the CPI in the instruction operand to refer to the clone.
for (unsigned j = 0, e = UserMI->getNumOperands(); j != e; ++j)
- if (UserMI->getOperand(j).isConstantPoolIndex()) {
- UserMI->getOperand(j).setConstantPoolIndex(CPEs[i].CPI);
+ if (UserMI->getOperand(j).isCPI()) {
+ UserMI->getOperand(j).setIndex(CPEs[i].CPI);
break;
}
// Adjust the refcount of the clone...
return (Opc == ARM::tB) ? ((1<<10)-1)*2 : ((1<<23)-1)*4;
}
+/// AcceptWater - Small amount of common code factored out of the following.
+
+MachineBasicBlock* ARMConstantIslands::AcceptWater(MachineBasicBlock *WaterBB,
+ std::vector<MachineBasicBlock*>::iterator IP) {
+ DOUT << "found water in range\n";
+ // Remove the original WaterList entry; we want subsequent
+ // insertions in this vicinity to go after the one we're
+ // about to insert. This considerably reduces the number
+ // of times we have to move the same CPE more than once.
+ WaterList.erase(IP);
+ // CPE goes before following block (NewMBB).
+ return next(MachineFunction::iterator(WaterBB));
+}
+
/// LookForWater - look for an existing entry in the WaterList in which
/// we can place the CPE referenced from U so it's within range of U's MI.
/// Returns true if found, false if not. If it returns true, *NewMBB
-/// is set to the WaterList entry, and *PadNewWater is set to false if
-/// the WaterList entry is an island.
+/// is set to the WaterList entry.
+/// For ARM, we prefer the water that's farthest away. For Thumb, prefer
+/// water that will not introduce padding to water that will; within each
+/// group, prefer the water that's farthest away.
bool ARMConstantIslands::LookForWater(CPUser &U, unsigned UserOffset,
- bool *PadNewWater, MachineBasicBlock** NewMBB) {
+ 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.MaxDisp)) {
- DOUT << "found water in range\n";
- // CPE goes before following block (NewMBB).
- *NewMBB = next(MachineFunction::iterator(WaterBB));
- // If WaterBB is an island, don't pad the new island.
- // If WaterBB is empty, go backwards until we find something that
- // isn't. WaterBB may become empty if it's an island whose
- // contents were moved farther back.
- if (isThumb) {
- MachineBasicBlock* BB = WaterBB;
- while (BB->empty())
- BB = prior(MachineFunction::iterator(BB));
- if (BB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
- *PadNewWater = false;
+ if (WaterIsInRange(UserOffset, WaterBB, U)) {
+ if (isThumb &&
+ (BBOffsets[WaterBB->getNumber()] +
+ BBSizes[WaterBB->getNumber()])%4 != 0) {
+ // This is valid Water, but would introduce padding. Remember
+ // it in case we don't find any Water that doesn't do this.
+ if (!WaterBBThatWouldPad) {
+ WaterBBThatWouldPad = WaterBB;
+ IPThatWouldPad = IP;
+ }
+ } else {
+ *NewMBB = AcceptWater(WaterBB, IP);
+ return true;
}
- // Remove the original WaterList entry; we want subsequent
- // insertions in this vicinity to go after the one we're
- // about to insert. This considerably reduces the number
- // of times we have to move the same CPE more than once.
- WaterList.erase(IP);
- return true;
- }
+ }
if (IP == B)
break;
}
}
+ if (isThumb && WaterBBThatWouldPad) {
+ *NewMBB = AcceptWater(WaterBBThatWouldPad, IPThatWouldPad);
+ return true;
+ }
return false;
}
MachineBasicBlock *UserMBB = UserMI->getParent();
unsigned OffsetOfNextBlock = BBOffsets[UserMBB->getNumber()] +
BBSizes[UserMBB->getNumber()];
- assert(OffsetOfNextBlock = BBOffsets[UserMBB->getNumber()+1]);
+ assert(OffsetOfNextBlock== BBOffsets[UserMBB->getNumber()+1]);
// If the use is at the end of the block, or the end of the block
- // is within range, make new water there. (The +2 or 4 below is
- // for the unconditional branch we will be adding. If the block ends in
- // an unconditional branch already, it is water, and is known to
- // be out of range, so we'll always be adding one.)
+ // is within range, make new water there. (The addition below is
+ // for the unconditional branch we will be adding: 4 bytes on ARM,
+ // 2 on Thumb. Possible Thumb alignment padding is allowed for
+ // inside OffsetIsInRange.
+ // If the block ends in an unconditional branch already, it is water,
+ // and is known to be out of range, so we'll always be adding a branch.)
if (&UserMBB->back() == UserMI ||
- OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb ? 2 : 4),
- U.MaxDisp, !isThumb)) {
+ 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!");
// not work well to put CPE as far forward as possible, since then
// CPE' cannot immediately follow it (that location is 2 bytes
// farther away from I+1 than CPE was from I) and we'd need to create
- // a new island.
+ // a new island. So, we make a first guess, then walk through the
+ // instructions between the one currently being looked at and the
+ // possible insertion point, and make sure any other instructions
+ // that reference CPEs will be able to use the same island area;
+ // if not, we back up the insertion point.
+
// The 4 in the following is for the unconditional branch we'll be
- // inserting (allows for long branch on Thumb). The 2 or 0 is for
- // alignment of the island.
- unsigned BaseInsertOffset = UserOffset + U.MaxDisp -4 + (isThumb ? 2 : 0);
+ // inserting (allows for long branch on Thumb). Alignment of the
+ // island is handled inside OffsetIsInRange.
+ unsigned BaseInsertOffset = UserOffset + U.MaxDisp -4;
// This could point off the end of the block if we've already got
// constant pool entries following this block; only the last one is
// in the water list. Back past any possible branches (allow for a
MachineBasicBlock::iterator MI = UserMI;
++MI;
unsigned CPUIndex = CPUserIndex+1;
- for (unsigned Offset = UserOffset+ARM::GetInstSize(UserMI);
+ for (unsigned Offset = UserOffset+TII->GetInstSizeInBytes(UserMI);
Offset < BaseInsertOffset;
- Offset += ARM::GetInstSize(MI),
+ Offset += TII->GetInstSizeInBytes(MI),
MI = next(MI)) {
if (CPUIndex < CPUsers.size() && CPUsers[CPUIndex].MI == MI) {
if (!OffsetIsInRange(Offset, EndInsertOffset,
CPUser &U = CPUsers[CPUserIndex];
MachineInstr *UserMI = U.MI;
MachineInstr *CPEMI = U.CPEMI;
- unsigned CPI = CPEMI->getOperand(1).getConstantPoolIndex();
+ unsigned CPI = CPEMI->getOperand(1).getIndex();
unsigned Size = CPEMI->getOperand(2).getImm();
MachineBasicBlock *NewMBB;
- // Compute this only once, it's expensive
+ // Compute this only once, it's expensive. The 4 or 8 is the value the
+ // hardware keeps in the PC (2 insns ahead of the reference).
unsigned UserOffset = GetOffsetOf(UserMI) + (isThumb ? 4 : 8);
+
+ // Special case: tLEApcrel are two instructions MI's. The actual user is the
+ // second instruction.
+ if (UserMI->getOpcode() == ARM::tLEApcrel)
+ UserOffset += 2;
// See if the current entry is within range, or there is a clone of it
// in range.
// No existing clone of this CPE is within range.
// We will be generating a new clone. Get a UID for it.
- unsigned ID = NextUID++;
+ unsigned ID = AFI->createConstPoolEntryUId();
// Look for water where we can place this CPE. We look for the farthest one
// away that will work. Forward references only for now (although later
// we might find some that are backwards).
- bool PadNewWater = true;
- if (!LookForWater(U, UserOffset, &PadNewWater, &NewMBB)) {
+ if (!LookForWater(U, UserOffset, &NewMBB)) {
// No water found.
DOUT << "No water found\n";
CreateNewWater(CPUserIndex, UserOffset, &NewMBB);
}
// Okay, we know we can put an island before NewMBB now, do it!
- MachineBasicBlock *NewIsland = new MachineBasicBlock();
- Fn.getBasicBlockList().insert(NewMBB, NewIsland);
+ MachineBasicBlock *NewIsland = Fn.CreateMachineBasicBlock();
+ Fn.insert(NewMBB, NewIsland);
// Update internal data structures to account for the newly inserted MBB.
UpdateForInsertedWaterBlock(NewIsland);
CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
NumCPEs++;
+ BBOffsets[NewIsland->getNumber()] = BBOffsets[NewMBB->getNumber()];
// Compensate for .align 2 in thumb mode.
- if (isThumb && PadNewWater) Size += 2;
+ if (isThumb && BBOffsets[NewIsland->getNumber()]%4 != 0)
+ Size += 2;
// Increase the size of the island block to account for the new entry.
BBSizes[NewIsland->getNumber()] += Size;
- BBOffsets[NewIsland->getNumber()] = BBOffsets[NewMBB->getNumber()];
AdjustBBOffsetsAfter(NewIsland, Size);
// Finally, change the CPI in the instruction operand to be ID.
for (unsigned i = 0, e = UserMI->getNumOperands(); i != e; ++i)
- if (UserMI->getOperand(i).isConstantPoolIndex()) {
- UserMI->getOperand(i).setConstantPoolIndex(ID);
+ if (UserMI->getOperand(i).isCPI()) {
+ UserMI->getOperand(i).setIndex(ID);
break;
}
/// sizes and offsets of impacted basic blocks.
void ARMConstantIslands::RemoveDeadCPEMI(MachineInstr *CPEMI) {
MachineBasicBlock *CPEBB = CPEMI->getParent();
+ unsigned Size = CPEMI->getOperand(2).getImm();
+ CPEMI->eraseFromParent();
+ BBSizes[CPEBB->getNumber()] -= Size;
+ // All succeeding offsets have the current size value added in, fix this.
if (CPEBB->empty()) {
- // In thumb mode, the size of island is padded by two to compensate for
- // the alignment requirement. Thus it will now be 2 when the block is
+ // In thumb mode, the size of island may be padded by two to compensate for
+ // the alignment requirement. Then it will now be 2 when the block is
// empty, so fix this.
// All succeeding offsets have the current size value added in, fix this.
if (BBSizes[CPEBB->getNumber()] != 0) {
- AdjustBBOffsetsAfter(CPEBB, -BBSizes[CPEBB->getNumber()]);
+ Size += BBSizes[CPEBB->getNumber()];
BBSizes[CPEBB->getNumber()] = 0;
}
- // An island has only one predecessor BB and one successor BB. Check if
- // this BB's predecessor jumps directly to this BB's successor. This
- // shouldn't happen currently.
- assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
- // FIXME: remove the empty blocks after all the work is done?
- } else {
- unsigned Size = CPEMI->getOperand(2).getImm();
- BBSizes[CPEBB->getNumber()] -= Size;
- // All succeeding offsets have the current size value added in, fix this.
- AdjustBBOffsetsAfter(CPEBB, -Size);
}
-
- CPEMI->eraseFromParent();
+ AdjustBBOffsetsAfter(CPEBB, -Size);
+ // An island has only one predecessor BB and one successor BB. Check if
+ // this BB's predecessor jumps directly to this BB's successor. This
+ // shouldn't happen currently.
+ assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
+ // FIXME: remove the empty blocks after all the work is done?
}
/// RemoveUnusedCPEntries - Remove constant pool entries whose refcounts
DOUT << "Branch of destination BB#" << DestBB->getNumber()
<< " from BB#" << MI->getParent()->getNumber()
<< " max delta=" << MaxDisp
- << " at offset " << int(DestOffset-BrOffset) << "\t" << *MI;
+ << " from " << GetOffsetOf(MI) << " to " << DestOffset
+ << " offset " << int(DestOffset-BrOffset) << "\t" << *MI;
- return OffsetIsInRange(BrOffset, DestOffset, MaxDisp, true);
+ if (BrOffset <= DestOffset) {
+ // Branch before the Dest.
+ if (DestOffset-BrOffset <= MaxDisp)
+ return true;
+ } else {
+ if (BrOffset-DestOffset <= MaxDisp)
+ return true;
+ }
+ return false;
}
/// FixUpImmediateBr - Fix up an immediate branch whose destination is too far
/// away to fit in its displacement field.
bool ARMConstantIslands::FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
- MachineBasicBlock *DestBB = MI->getOperand(0).getMachineBasicBlock();
+ MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
// Check to see if the DestBB is already in-range.
if (BBIsInRange(MI, DestBB, Br.MaxDisp))
// Use BL to implement far jump.
Br.MaxDisp = (1 << 21) * 2;
- MI->setInstrDescriptor(TII->get(ARM::tBfar));
+ MI->setDesc(TII->get(ARM::tBfar));
BBSizes[MBB->getNumber()] += 2;
AdjustBBOffsetsAfter(MBB, 2);
HasFarJump = true;
bool
ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
- MachineBasicBlock *DestBB = MI->getOperand(0).getMachineBasicBlock();
+ MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
// Add a unconditional branch to the destination and invert the branch
// condition to jump over it:
// bge L2
// b L1
// L2:
- ARMCC::CondCodes CC = (ARMCC::CondCodes)MI->getOperand(1).getImmedValue();
+ ARMCC::CondCodes CC = (ARMCC::CondCodes)MI->getOperand(1).getImm();
CC = ARMCC::getOppositeCondition(CC);
+ unsigned CCReg = MI->getOperand(2).getReg();
// If the branch is at the end of its MBB and that has a fall-through block,
// direct the updated conditional branch to the fall-through block. Otherwise,
NumCBrFixed++;
if (BMI != MI) {
- if (next(MachineBasicBlock::iterator(MI)) == MBB->back() &&
+ if (next(MachineBasicBlock::iterator(MI)) == prior(MBB->end()) &&
BMI->getOpcode() == Br.UncondBr) {
// Last MI in the BB is a unconditional branch. Can we simply invert the
// condition and swap destinations:
// =>
// bne L2
// b L1
- MachineBasicBlock *NewDest = BMI->getOperand(0).getMachineBasicBlock();
+ 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).setMachineBasicBlock(DestBB);
- MI->getOperand(0).setMachineBasicBlock(NewDest);
+ BMI->getOperand(0).setMBB(DestBB);
+ MI->getOperand(0).setMBB(NewDest);
MI->getOperand(1).setImm(CC);
return true;
}
SplitBlockBeforeInstr(MI);
// No need for the branch to the next block. We're adding a unconditional
// branch to the destination.
+ int delta = TII->GetInstSizeInBytes(&MBB->back());
+ BBSizes[MBB->getNumber()] -= delta;
+ MachineBasicBlock* SplitBB = next(MachineFunction::iterator(MBB));
+ AdjustBBOffsetsAfter(SplitBB, -delta);
MBB->back().eraseFromParent();
+ // BBOffsets[SplitBB] is wrong temporarily, fixed below
}
MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
<< " also invert condition and change dest. to BB#"
<< NextBB->getNumber() << "\n";
- // Insert a unconditional branch and replace the conditional branch.
+ // Insert a new conditional branch and a new unconditional branch.
// Also update the ImmBranch as well as adding a new entry for the new branch.
- BuildMI(MBB, TII->get(MI->getOpcode())).addMBB(NextBB).addImm(CC);
+ BuildMI(MBB, TII->get(MI->getOpcode())).addMBB(NextBB)
+ .addImm(CC).addReg(CCReg);
Br.MI = &MBB->back();
+ BBSizes[MBB->getNumber()] += TII->GetInstSizeInBytes(&MBB->back());
BuildMI(MBB, 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));
+
+ // Remove the old conditional branch. It may or may not still be in MBB.
+ BBSizes[MI->getParent()->getNumber()] -= TII->GetInstSizeInBytes(MI);
MI->eraseFromParent();
- // Increase the size of MBB to account for the new unconditional branch.
- int delta = ARM::GetInstSize(&MBB->back());
- BBSizes[MBB->getNumber()] += delta;
+ // The net size change is an addition of one unconditional branch.
+ int delta = TII->GetInstSizeInBytes(&MBB->back());
AdjustBBOffsetsAfter(MBB, delta);
return true;
}
bool MadeChange = false;
for (unsigned i = 0, e = PushPopMIs.size(); i != e; ++i) {
MachineInstr *MI = PushPopMIs[i];
- if (MI->getNumOperands() == 1) {
- if (MI->getOpcode() == ARM::tPOP_RET &&
- MI->getOperand(0).getReg() == ARM::PC)
- BuildMI(MI->getParent(), TII->get(ARM::tBX_RET));
- MI->eraseFromParent();
- MadeChange = true;
+ if (MI->getOpcode() == ARM::tPOP_RET &&
+ MI->getOperand(0).getReg() == ARM::PC &&
+ MI->getNumExplicitOperands() == 1) {
+ BuildMI(MI->getParent(), TII->get(ARM::tBX_RET));
+ MI->eraseFromParent();
+ MadeChange = true;
}
}
return MadeChange;