mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-23 17:29:19 +00:00
Rewrite of Thumb constant islands handling (exact allowance for padding
around islands and jump tables). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36573 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
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@ -51,10 +51,14 @@ namespace {
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unsigned NextUID;
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unsigned NextUID;
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/// BBSizes - The size of each MachineBasicBlock in bytes of code, indexed
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/// BBSizes - The size of each MachineBasicBlock in bytes of code, indexed
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/// by MBB Number.
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/// by MBB Number. The two-byte pads required for Thumb alignment are
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/// counted as part of the following block (i.e., the offset and size for
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/// a padded block will both be ==2 mod 4).
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std::vector<unsigned> BBSizes;
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std::vector<unsigned> BBSizes;
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/// BBOffsets - the offset of each MBB in bytes, starting from 0.
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/// BBOffsets - the offset of each MBB in bytes, starting from 0.
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/// The two-byte pads required for Thumb alignment are counted as part of
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/// the following block.
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std::vector<unsigned> BBOffsets;
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std::vector<unsigned> BBOffsets;
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/// WaterList - A sorted list of basic blocks where islands could be placed
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/// WaterList - A sorted list of basic blocks where islands could be placed
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@ -121,6 +125,7 @@ namespace {
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bool HasFarJump;
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bool HasFarJump;
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const TargetInstrInfo *TII;
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const TargetInstrInfo *TII;
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ARMFunctionInfo *AFI;
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bool isThumb;
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bool isThumb;
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public:
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public:
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virtual bool runOnMachineFunction(MachineFunction &Fn);
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virtual bool runOnMachineFunction(MachineFunction &Fn);
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@ -140,8 +145,10 @@ namespace {
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void AdjustBBOffsetsAfter(MachineBasicBlock *BB, int delta);
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void AdjustBBOffsetsAfter(MachineBasicBlock *BB, int delta);
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bool DecrementOldEntry(unsigned CPI, MachineInstr* CPEMI);
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bool DecrementOldEntry(unsigned CPI, MachineInstr* CPEMI);
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int LookForExistingCPEntry(CPUser& U, unsigned UserOffset);
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int LookForExistingCPEntry(CPUser& U, unsigned UserOffset);
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bool LookForWater(CPUser&U, unsigned UserOffset, bool* PadNewWater,
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bool LookForWater(CPUser&U, unsigned UserOffset,
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MachineBasicBlock** NewMBB);
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MachineBasicBlock** NewMBB);
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MachineBasicBlock* AcceptWater(MachineBasicBlock *WaterBB,
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std::vector<MachineBasicBlock*>::iterator IP);
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void CreateNewWater(unsigned CPUserIndex, unsigned UserOffset,
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void CreateNewWater(unsigned CPUserIndex, unsigned UserOffset,
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MachineBasicBlock** NewMBB);
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MachineBasicBlock** NewMBB);
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bool HandleConstantPoolUser(MachineFunction &Fn, unsigned CPUserIndex);
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bool HandleConstantPoolUser(MachineFunction &Fn, unsigned CPUserIndex);
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@ -161,9 +168,38 @@ namespace {
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bool UndoLRSpillRestore();
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bool UndoLRSpillRestore();
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unsigned GetOffsetOf(MachineInstr *MI) const;
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unsigned GetOffsetOf(MachineInstr *MI) const;
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void dumpBBs();
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void verify(MachineFunction &Fn);
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};
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};
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}
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}
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/// verify - check BBOffsets, BBSizes, alignment of islands
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void ARMConstantIslands::verify(MachineFunction &Fn) {
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assert(BBOffsets.size() == BBSizes.size());
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for (unsigned i = 1, e = BBOffsets.size(); i != e; ++i)
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assert(BBOffsets[i-1]+BBSizes[i-1] == BBOffsets[i]);
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if (isThumb) {
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for (MachineFunction::iterator MBBI = Fn.begin(), E = Fn.end();
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MBBI != E; ++MBBI) {
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MachineBasicBlock *MBB = MBBI;
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if (!MBB->empty() &&
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MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
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assert((BBOffsets[MBB->getNumber()]%4 == 0 &&
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BBSizes[MBB->getNumber()]%4 == 0) ||
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(BBOffsets[MBB->getNumber()]%4 != 0 &&
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BBSizes[MBB->getNumber()]%4 != 0));
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}
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}
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}
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/// print block size and offset information - debugging
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void ARMConstantIslands::dumpBBs() {
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for (unsigned J = 0, E = BBOffsets.size(); J !=E; ++J) {
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DOUT << "block" << J << " offset" << BBOffsets[J] <<
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" size" << BBSizes[J] << "\n";
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}
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}
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/// createARMConstantIslandPass - returns an instance of the constpool
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/// createARMConstantIslandPass - returns an instance of the constpool
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/// island pass.
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/// island pass.
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FunctionPass *llvm::createARMConstantIslandPass() {
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FunctionPass *llvm::createARMConstantIslandPass() {
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@ -172,9 +208,9 @@ FunctionPass *llvm::createARMConstantIslandPass() {
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bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
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bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
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MachineConstantPool &MCP = *Fn.getConstantPool();
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MachineConstantPool &MCP = *Fn.getConstantPool();
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ARMFunctionInfo *AFI = Fn.getInfo<ARMFunctionInfo>();
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TII = Fn.getTarget().getInstrInfo();
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TII = Fn.getTarget().getInstrInfo();
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AFI = Fn.getInfo<ARMFunctionInfo>();
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isThumb = AFI->isThumbFunction();
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isThumb = AFI->isThumbFunction();
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HasFarJump = false;
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HasFarJump = false;
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@ -215,13 +251,18 @@ bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
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bool Change = false;
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bool Change = false;
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for (unsigned i = 0, e = CPUsers.size(); i != e; ++i)
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for (unsigned i = 0, e = CPUsers.size(); i != e; ++i)
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Change |= HandleConstantPoolUser(Fn, i);
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Change |= HandleConstantPoolUser(Fn, i);
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DEBUG(dumpBBs());
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for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
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for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
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Change |= FixUpImmediateBr(Fn, ImmBranches[i]);
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Change |= FixUpImmediateBr(Fn, ImmBranches[i]);
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DEBUG(dumpBBs());
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if (!Change)
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if (!Change)
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break;
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break;
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MadeChange = true;
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MadeChange = true;
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}
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}
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// After a while, this might be made debug-only, but it is not expensive.
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verify(Fn);
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// If LR has been forced spilled and no far jumps (i.e. BL) has been issued.
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// If LR has been forced spilled and no far jumps (i.e. BL) has been issued.
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// Undo the spill / restore of LR if possible.
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// Undo the spill / restore of LR if possible.
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if (!HasFarJump && AFI->isLRSpilledForFarJump() && isThumb)
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if (!HasFarJump && AFI->isLRSpilledForFarJump() && isThumb)
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@ -332,8 +373,15 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
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unsigned Scale = 1;
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unsigned Scale = 1;
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int UOpc = Opc;
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int UOpc = Opc;
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switch (Opc) {
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switch (Opc) {
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case ARM::tBR_JTr:
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// A Thumb table jump may involve padding; for the offsets to
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// be right, functions containing these must be 4-byte aligned.
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AFI->setAlign(2U);
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if ((Offset+MBBSize)%4 != 0)
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MBBSize += 2; // padding
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continue; // Does not get an entry in ImmBranches
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default:
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default:
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continue; // Ignore JT branches
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continue; // Ignore other JT branches
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case ARM::Bcc:
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case ARM::Bcc:
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isCond = true;
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isCond = true;
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UOpc = ARM::B;
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UOpc = ARM::B;
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@ -431,12 +479,12 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
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}
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}
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}
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}
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// In thumb mode, if this block is a constpool island, pessimistically
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// In thumb mode, if this block is a constpool island, we may need padding
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// assume it needs to be padded by two byte so it's aligned on 4 byte
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// so it's aligned on 4 byte boundary.
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// boundary.
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if (isThumb &&
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if (isThumb &&
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!MBB.empty() &&
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!MBB.empty() &&
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MBB.begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
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MBB.begin()->getOpcode() == ARM::CONSTPOOL_ENTRY &&
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(Offset%4) != 0)
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MBBSize += 2;
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MBBSize += 2;
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BBSizes.push_back(MBBSize);
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BBSizes.push_back(MBBSize);
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@ -456,6 +504,13 @@ unsigned ARMConstantIslands::GetOffsetOf(MachineInstr *MI) const {
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// it is in.
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// it is in.
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unsigned Offset = BBOffsets[MBB->getNumber()];
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unsigned Offset = BBOffsets[MBB->getNumber()];
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// If we're looking for a CONSTPOOL_ENTRY in Thumb, see if this block has
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// alignment padding, and compensate if so.
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if (isThumb &&
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MI->getOpcode() == ARM::CONSTPOOL_ENTRY &&
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Offset%4 != 0)
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Offset += 2;
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// Sum instructions before MI in MBB.
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// Sum instructions before MI in MBB.
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for (MachineBasicBlock::iterator I = MBB->begin(); ; ++I) {
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for (MachineBasicBlock::iterator I = MBB->begin(); ; ++I) {
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assert(I != MBB->end() && "Didn't find MI in its own basic block?");
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assert(I != MBB->end() && "Didn't find MI in its own basic block?");
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@ -553,7 +608,8 @@ MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
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else
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else
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WaterList.insert(IP, OrigBB);
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WaterList.insert(IP, OrigBB);
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// Figure out how large the first NewMBB is.
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// Figure out how large the first NewMBB is. (It cannot
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// contain a constpool_entry or tablejump.)
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unsigned NewBBSize = 0;
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unsigned NewBBSize = 0;
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for (MachineBasicBlock::iterator I = NewBB->begin(), E = NewBB->end();
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for (MachineBasicBlock::iterator I = NewBB->begin(), E = NewBB->end();
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I != E; ++I)
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I != E; ++I)
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@ -578,10 +634,21 @@ MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
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return NewBB;
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return NewBB;
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}
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}
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/// OffsetIsInRange - Checks whether UserOffset is within MaxDisp of
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/// OffsetIsInRange - Checks whether UserOffset (the location of a constant pool
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/// TrialOffset.
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/// reference) is within MaxDisp of TrialOffset (a proposed location of a
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/// constant pool entry).
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bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
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bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
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unsigned TrialOffset, unsigned MaxDisp, bool NegativeOK) {
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unsigned TrialOffset, unsigned MaxDisp, bool NegativeOK) {
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// On Thumb offsets==2 mod 4 are rounded down by the hardware for
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// purposes of the displacement computation; compensate for that here.
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// Effectively, the valid range of displacements is 2 bytes smaller for such
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// references.
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if (isThumb && UserOffset%4 !=0)
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UserOffset -= 2;
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// CPEs will be rounded up to a multiple of 4.
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if (isThumb && TrialOffset%4 != 0)
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TrialOffset += 2;
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if (UserOffset <= TrialOffset) {
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if (UserOffset <= TrialOffset) {
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// User before the Trial.
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// User before the Trial.
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if (TrialOffset-UserOffset <= MaxDisp)
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if (TrialOffset-UserOffset <= MaxDisp)
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@ -599,19 +666,15 @@ bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
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bool ARMConstantIslands::WaterIsInRange(unsigned UserOffset,
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bool ARMConstantIslands::WaterIsInRange(unsigned UserOffset,
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MachineBasicBlock* Water, unsigned MaxDisp)
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MachineBasicBlock* Water, unsigned MaxDisp)
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{
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{
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MachineFunction::iterator I = next(MachineFunction::iterator(Water));
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unsigned CPEOffset = BBOffsets[Water->getNumber()] +
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unsigned CPEOffset = BBOffsets[Water->getNumber()] +
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BBSizes[Water->getNumber()];
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BBSizes[Water->getNumber()];
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// If the Water is a constpool island, it has already been aligned.
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// If not, align it.
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if (isThumb &&
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(Water->empty() ||
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Water->begin()->getOpcode() != ARM::CONSTPOOL_ENTRY))
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CPEOffset += 2;
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// If the CPE is to be inserted before the instruction, that will raise
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// If the CPE is to be inserted before the instruction, that will raise
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// the offset of the instruction.
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// the offset of the instruction. (Currently applies only to ARM, so
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// no alignment compensation attempted here.)
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if (CPEOffset < UserOffset)
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if (CPEOffset < UserOffset)
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UserOffset += isThumb ? 2 : 4;
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UserOffset += 4;
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return OffsetIsInRange (UserOffset, CPEOffset, MaxDisp, !isThumb);
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return OffsetIsInRange (UserOffset, CPEOffset, MaxDisp, !isThumb);
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}
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}
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@ -621,10 +684,8 @@ bool ARMConstantIslands::WaterIsInRange(unsigned UserOffset,
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bool ARMConstantIslands::CPEIsInRange(MachineInstr *MI, unsigned UserOffset,
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bool ARMConstantIslands::CPEIsInRange(MachineInstr *MI, unsigned UserOffset,
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MachineInstr *CPEMI,
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MachineInstr *CPEMI,
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unsigned MaxDisp, bool DoDump) {
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unsigned MaxDisp, bool DoDump) {
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// In thumb mode, pessimistically assumes the .align 2 before the first CPE
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unsigned CPEOffset = GetOffsetOf(CPEMI);
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// in the island adds two byte padding.
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assert(CPEOffset%4 == 0 && "Misaligned CPE");
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unsigned AlignAdj = isThumb ? 2 : 0;
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unsigned CPEOffset = GetOffsetOf(CPEMI) + AlignAdj;
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if (DoDump) {
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if (DoDump) {
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DOUT << "User of CPE#" << CPEMI->getOperand(0).getImm()
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DOUT << "User of CPE#" << CPEMI->getOperand(0).getImm()
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@ -651,11 +712,56 @@ static bool BBIsJumpedOver(MachineBasicBlock *MBB) {
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return false;
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return false;
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}
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}
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void ARMConstantIslands::AdjustBBOffsetsAfter(MachineBasicBlock *BB, int delta)
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void ARMConstantIslands::AdjustBBOffsetsAfter(MachineBasicBlock *BB,
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{
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int delta) {
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MachineFunction::iterator MBBI = BB->getParent()->end();
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MachineFunction::iterator MBBI = BB; MBBI = next(MBBI);
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for(unsigned i=BB->getNumber()+1; i<BB->getParent()->getNumBlockIDs(); i++)
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for(unsigned i=BB->getNumber()+1; i<BB->getParent()->getNumBlockIDs(); i++) {
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BBOffsets[i] += delta;
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BBOffsets[i] += delta;
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// If some existing blocks have padding, adjust the padding as needed, a
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// bit tricky. delta can be negative so don't use % on that.
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if (isThumb) {
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MachineBasicBlock *MBB = MBBI;
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if (!MBB->empty()) {
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// Constant pool entries require padding.
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if (MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY) {
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unsigned oldOffset = BBOffsets[i] - delta;
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if (oldOffset%4==0 && BBOffsets[i]%4!=0) {
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// add new padding
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BBSizes[i] += 2;
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delta += 2;
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} else if (oldOffset%4!=0 && BBOffsets[i]%4==0) {
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// remove existing padding
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BBSizes[i] -=2;
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delta -= 2;
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}
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}
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// Thumb jump tables require padding. They can be at the end, or
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// followed by an unconditional branch.
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MachineInstr *ThumbJTMI = NULL;
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if (prior(MBB->end())->getOpcode() == ARM::tBR_JTr)
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ThumbJTMI = prior(MBB->end());
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else if (prior(MBB->end()) != MBB->begin() &&
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prior(prior(MBB->end()))->getOpcode() == ARM::tBR_JTr)
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ThumbJTMI = prior(prior(MBB->end()));
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if (ThumbJTMI) {
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unsigned newMIOffset = GetOffsetOf(ThumbJTMI);
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unsigned oldMIOffset = newMIOffset - delta;
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if (oldMIOffset%4 == 0 && newMIOffset%4 != 0) {
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// remove existing padding
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BBSizes[i] -= 2;
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delta -= 2;
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} else if (oldMIOffset%4 != 0 && newMIOffset%4 == 0) {
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// add new padding
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BBSizes[i] += 2;
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delta += 2;
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}
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}
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if (delta==0)
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return;
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}
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MBBI = next(MBBI);
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}
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}
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}
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}
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/// DecrementOldEntry - find the constant pool entry with index CPI
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/// DecrementOldEntry - find the constant pool entry with index CPI
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@ -729,44 +835,59 @@ static inline unsigned getUnconditionalBrDisp(int Opc) {
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return (Opc == ARM::tB) ? ((1<<10)-1)*2 : ((1<<23)-1)*4;
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return (Opc == ARM::tB) ? ((1<<10)-1)*2 : ((1<<23)-1)*4;
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}
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}
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/// AcceptWater - Small amount of common code factored out of the following.
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MachineBasicBlock* ARMConstantIslands::AcceptWater(MachineBasicBlock *WaterBB,
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std::vector<MachineBasicBlock*>::iterator IP) {
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DOUT << "found water in range\n";
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// Remove the original WaterList entry; we want subsequent
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// insertions in this vicinity to go after the one we're
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// about to insert. This considerably reduces the number
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// of times we have to move the same CPE more than once.
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WaterList.erase(IP);
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// CPE goes before following block (NewMBB).
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return next(MachineFunction::iterator(WaterBB));
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}
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/// LookForWater - look for an existing entry in the WaterList in which
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/// 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.
|
/// 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
|
/// 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
|
/// is set to the WaterList entry.
|
||||||
/// the WaterList entry is an island.
|
/// 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 ARMConstantIslands::LookForWater(CPUser &U, unsigned UserOffset,
|
||||||
bool *PadNewWater, MachineBasicBlock** NewMBB) {
|
MachineBasicBlock** NewMBB) {
|
||||||
|
std::vector<MachineBasicBlock*>::iterator IPThatWouldPad;
|
||||||
|
MachineBasicBlock* WaterBBThatWouldPad = NULL;
|
||||||
if (!WaterList.empty()) {
|
if (!WaterList.empty()) {
|
||||||
for (std::vector<MachineBasicBlock*>::iterator IP = prior(WaterList.end()),
|
for (std::vector<MachineBasicBlock*>::iterator IP = prior(WaterList.end()),
|
||||||
B = WaterList.begin();; --IP) {
|
B = WaterList.begin();; --IP) {
|
||||||
MachineBasicBlock* WaterBB = *IP;
|
MachineBasicBlock* WaterBB = *IP;
|
||||||
if (WaterIsInRange(UserOffset, WaterBB, U.MaxDisp)) {
|
if (WaterIsInRange(UserOffset, WaterBB, U.MaxDisp)) {
|
||||||
DOUT << "found water in range\n";
|
if (isThumb &&
|
||||||
// CPE goes before following block (NewMBB).
|
(BBOffsets[WaterBB->getNumber()] +
|
||||||
*NewMBB = next(MachineFunction::iterator(WaterBB));
|
BBSizes[WaterBB->getNumber()])%4 != 0) {
|
||||||
// If WaterBB is an island, don't pad the new island.
|
// This is valid Water, but would introduce padding. Remember
|
||||||
// If WaterBB is empty, go backwards until we find something that
|
// it in case we don't find any Water that doesn't do this.
|
||||||
// isn't. WaterBB may become empty if it's an island whose
|
if (!WaterBBThatWouldPad) {
|
||||||
// contents were moved farther back.
|
WaterBBThatWouldPad = WaterBB;
|
||||||
if (isThumb) {
|
IPThatWouldPad = IP;
|
||||||
MachineBasicBlock* BB = WaterBB;
|
}
|
||||||
while (BB->empty())
|
} else {
|
||||||
BB = prior(MachineFunction::iterator(BB));
|
*NewMBB = AcceptWater(WaterBB, IP);
|
||||||
if (BB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
|
return true;
|
||||||
*PadNewWater = false;
|
|
||||||
}
|
}
|
||||||
// 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)
|
if (IP == B)
|
||||||
break;
|
break;
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
if (isThumb && WaterBBThatWouldPad) {
|
||||||
|
*NewMBB = AcceptWater(WaterBBThatWouldPad, IPThatWouldPad);
|
||||||
|
return true;
|
||||||
|
}
|
||||||
return false;
|
return false;
|
||||||
}
|
}
|
||||||
|
|
||||||
@ -786,16 +907,18 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
|
|||||||
MachineBasicBlock *UserMBB = UserMI->getParent();
|
MachineBasicBlock *UserMBB = UserMI->getParent();
|
||||||
unsigned OffsetOfNextBlock = BBOffsets[UserMBB->getNumber()] +
|
unsigned OffsetOfNextBlock = BBOffsets[UserMBB->getNumber()] +
|
||||||
BBSizes[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
|
// 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
|
// is within range, make new water there. (The addition below is
|
||||||
// for the unconditional branch we will be adding. If the block ends in
|
// for the unconditional branch we will be adding: 4 bytes on ARM,
|
||||||
// an unconditional branch already, it is water, and is known to
|
// 2 on Thumb. Possible Thumb alignment padding is allowed for
|
||||||
// be out of range, so we'll always be adding one.)
|
// 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 ||
|
if (&UserMBB->back() == UserMI ||
|
||||||
OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb ? 2 : 4),
|
OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb ? 2: 4),
|
||||||
U.MaxDisp, !isThumb)) {
|
U.MaxDisp, !isThumb)) {
|
||||||
DOUT << "Split at end of block\n";
|
DOUT << "Split at end of block\n";
|
||||||
if (&UserMBB->back() == UserMI)
|
if (&UserMBB->back() == UserMI)
|
||||||
assert(BBHasFallthrough(UserMBB) && "Expected a fallthrough BB!");
|
assert(BBHasFallthrough(UserMBB) && "Expected a fallthrough BB!");
|
||||||
@ -821,11 +944,16 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
|
|||||||
// not work well to put CPE as far forward as possible, since then
|
// not work well to put CPE as far forward as possible, since then
|
||||||
// CPE' cannot immediately follow it (that location is 2 bytes
|
// 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
|
// 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
|
// 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
|
// inserting (allows for long branch on Thumb). Alignment of the
|
||||||
// alignment of the island.
|
// island is handled inside OffsetIsInRange.
|
||||||
unsigned BaseInsertOffset = UserOffset + U.MaxDisp -4 + (isThumb ? 2 : 0);
|
unsigned BaseInsertOffset = UserOffset + U.MaxDisp -4;
|
||||||
// This could point off the end of the block if we've already got
|
// 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
|
// constant pool entries following this block; only the last one is
|
||||||
// in the water list. Back past any possible branches (allow for a
|
// in the water list. Back past any possible branches (allow for a
|
||||||
@ -871,7 +999,8 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
|
|||||||
unsigned CPI = CPEMI->getOperand(1).getConstantPoolIndex();
|
unsigned CPI = CPEMI->getOperand(1).getConstantPoolIndex();
|
||||||
unsigned Size = CPEMI->getOperand(2).getImm();
|
unsigned Size = CPEMI->getOperand(2).getImm();
|
||||||
MachineBasicBlock *NewMBB;
|
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);
|
unsigned UserOffset = GetOffsetOf(UserMI) + (isThumb ? 4 : 8);
|
||||||
|
|
||||||
// Special case: tLEApcrel are two instructions MI's. The actual user is the
|
// Special case: tLEApcrel are two instructions MI's. The actual user is the
|
||||||
@ -892,9 +1021,8 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
|
|||||||
// Look for water where we can place this CPE. We look for the farthest one
|
// 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
|
// away that will work. Forward references only for now (although later
|
||||||
// we might find some that are backwards).
|
// we might find some that are backwards).
|
||||||
bool PadNewWater = true;
|
|
||||||
|
|
||||||
if (!LookForWater(U, UserOffset, &PadNewWater, &NewMBB)) {
|
if (!LookForWater(U, UserOffset, &NewMBB)) {
|
||||||
// No water found.
|
// No water found.
|
||||||
DOUT << "No water found\n";
|
DOUT << "No water found\n";
|
||||||
CreateNewWater(CPUserIndex, UserOffset, &NewMBB);
|
CreateNewWater(CPUserIndex, UserOffset, &NewMBB);
|
||||||
@ -917,11 +1045,12 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
|
|||||||
CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
|
CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
|
||||||
NumCPEs++;
|
NumCPEs++;
|
||||||
|
|
||||||
|
BBOffsets[NewIsland->getNumber()] = BBOffsets[NewMBB->getNumber()];
|
||||||
// Compensate for .align 2 in thumb mode.
|
// 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.
|
// Increase the size of the island block to account for the new entry.
|
||||||
BBSizes[NewIsland->getNumber()] += Size;
|
BBSizes[NewIsland->getNumber()] += Size;
|
||||||
BBOffsets[NewIsland->getNumber()] = BBOffsets[NewMBB->getNumber()];
|
|
||||||
AdjustBBOffsetsAfter(NewIsland, Size);
|
AdjustBBOffsetsAfter(NewIsland, Size);
|
||||||
|
|
||||||
// Finally, change the CPI in the instruction operand to be ID.
|
// Finally, change the CPI in the instruction operand to be ID.
|
||||||
@ -940,28 +1069,26 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
|
|||||||
/// sizes and offsets of impacted basic blocks.
|
/// sizes and offsets of impacted basic blocks.
|
||||||
void ARMConstantIslands::RemoveDeadCPEMI(MachineInstr *CPEMI) {
|
void ARMConstantIslands::RemoveDeadCPEMI(MachineInstr *CPEMI) {
|
||||||
MachineBasicBlock *CPEBB = CPEMI->getParent();
|
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()) {
|
if (CPEBB->empty()) {
|
||||||
// In thumb mode, the size of island is padded by two to compensate for
|
// In thumb mode, the size of island may be padded by two to compensate for
|
||||||
// the alignment requirement. Thus it will now be 2 when the block is
|
// the alignment requirement. Then it will now be 2 when the block is
|
||||||
// empty, so fix this.
|
// empty, so fix this.
|
||||||
// All succeeding offsets have the current size value added in, fix this.
|
// All succeeding offsets have the current size value added in, fix this.
|
||||||
if (BBSizes[CPEBB->getNumber()] != 0) {
|
if (BBSizes[CPEBB->getNumber()] != 0) {
|
||||||
AdjustBBOffsetsAfter(CPEBB, -BBSizes[CPEBB->getNumber()]);
|
Size += BBSizes[CPEBB->getNumber()];
|
||||||
BBSizes[CPEBB->getNumber()] = 0;
|
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);
|
|
||||||
}
|
}
|
||||||
|
AdjustBBOffsetsAfter(CPEBB, -Size);
|
||||||
CPEMI->eraseFromParent();
|
// 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
|
/// RemoveUnusedCPEntries - Remove constant pool entries whose refcounts
|
||||||
@ -992,9 +1119,18 @@ bool ARMConstantIslands::BBIsInRange(MachineInstr *MI,MachineBasicBlock *DestBB,
|
|||||||
DOUT << "Branch of destination BB#" << DestBB->getNumber()
|
DOUT << "Branch of destination BB#" << DestBB->getNumber()
|
||||||
<< " from BB#" << MI->getParent()->getNumber()
|
<< " from BB#" << MI->getParent()->getNumber()
|
||||||
<< " max delta=" << MaxDisp
|
<< " 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
|
/// FixUpImmediateBr - Fix up an immediate branch whose destination is too far
|
||||||
@ -1088,8 +1224,10 @@ ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
|
|||||||
// branch to the destination.
|
// branch to the destination.
|
||||||
int delta = ARM::GetInstSize(&MBB->back());
|
int delta = ARM::GetInstSize(&MBB->back());
|
||||||
BBSizes[MBB->getNumber()] -= delta;
|
BBSizes[MBB->getNumber()] -= delta;
|
||||||
AdjustBBOffsetsAfter(MBB, -delta);
|
MachineBasicBlock* SplitBB = next(MachineFunction::iterator(MBB));
|
||||||
|
AdjustBBOffsetsAfter(SplitBB, -delta);
|
||||||
MBB->back().eraseFromParent();
|
MBB->back().eraseFromParent();
|
||||||
|
// BBOffsets[SplitBB] is wrong temporarily, fixed below
|
||||||
}
|
}
|
||||||
MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
|
MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
|
||||||
|
|
||||||
|
@ -469,12 +469,13 @@ unsigned ARM::GetInstSize(MachineInstr *MI) {
|
|||||||
assert(JTI < JT.size());
|
assert(JTI < JT.size());
|
||||||
// Thumb instructions are 2 byte aligned, but JT entries are 4 byte
|
// Thumb instructions are 2 byte aligned, but JT entries are 4 byte
|
||||||
// 4 aligned. The assembler / linker may add 2 byte padding just before
|
// 4 aligned. The assembler / linker may add 2 byte padding just before
|
||||||
// the JT entries. Use + 4 even for tBR_JTr to purposely over-estimate
|
// the JT entries. The size does not include this padding; the
|
||||||
// the size the jumptable.
|
// constant islands pass does separate bookkeeping for it.
|
||||||
// FIXME: If we know the size of the function is less than (1 << 16) *2
|
// FIXME: If we know the size of the function is less than (1 << 16) *2
|
||||||
// bytes, we can use 16-bit entries instead. Then there won't be an
|
// bytes, we can use 16-bit entries instead. Then there won't be an
|
||||||
// alignment issue.
|
// alignment issue.
|
||||||
return getNumJTEntries(JT, JTI) * 4 + 4;
|
return getNumJTEntries(JT, JTI) * 4 +
|
||||||
|
(MI->getOpcode()==ARM::tBR_JTr ? 2 : 4);
|
||||||
}
|
}
|
||||||
default:
|
default:
|
||||||
// Otherwise, pseudo-instruction sizes are zero.
|
// Otherwise, pseudo-instruction sizes are zero.
|
||||||
|
Loading…
Reference in New Issue
Block a user