diff --git a/llvm/lib/Target/PIC16/PIC16MemSelOpt.cpp b/llvm/lib/Target/PIC16/PIC16MemSelOpt.cpp index cc71b04cc202..ab81ed1bca99 100644 --- a/llvm/lib/Target/PIC16/PIC16MemSelOpt.cpp +++ b/llvm/lib/Target/PIC16/PIC16MemSelOpt.cpp @@ -59,6 +59,7 @@ namespace { const TargetInstrInfo *TII; // Machine instruction info. MachineBasicBlock *MBB; // Current basic block std::string CurBank; + int PageChanged; }; char MemSelOpt::ID = 0; @@ -93,10 +94,56 @@ bool MemSelOpt::processBasicBlock(MachineFunction &MF, MachineBasicBlock &BB) { // Let us assume that when entering a basic block now bank is selected. // Ideally we should look at the predecessors for this information. CurBank=""; + PageChanged=0; - for (MachineBasicBlock::iterator I = BB.begin(); I != BB.end(); ++I) { + MachineBasicBlock::iterator I; + for (I = BB.begin(); I != BB.end(); ++I) { Changed |= processInstruction(I); + + // if the page has changed insert a page sel before + // any instruction that needs one + if (PageChanged == 1) + { + // Restore the page if it was changed, before leaving the basic block, + // because it may be required by the goto terminator or the fall thru + // basic blcok. + // If the terminator is return, we don't need to restore since there + // is no goto or fall thru basic block. + if ((I->getOpcode() == PIC16::sublw_3) || //macro has goto + (I->getOpcode() == PIC16::sublw_6) || //macro has goto + (I->getOpcode() == PIC16::addlwc) || //macro has goto + (TII->get(I->getOpcode()).isBranch())) + { + DebugLoc dl = I->getDebugLoc(); + BuildMI(*MBB, I, dl, TII->get(PIC16::pagesel)).addExternalSymbol("$"); + Changed = true; + PageChanged = 0; + } + } } + + // The basic block is over, but if we did not find any goto yet, + // we haven't restored the page. + // Restore the page if it was changed, before leaving the basic block, + // because it may be required by fall thru basic blcok. + // If the terminator is return, we don't need to restore since there + // is fall thru basic block. + if (PageChanged == 1) { + // save the end pointer before we move back to last insn. + MachineBasicBlock::iterator J = I; + I--; + const TargetInstrDesc &TID = TII->get(I->getOpcode()); + if (! TID.isReturn()) + { + DebugLoc dl = I->getDebugLoc(); + BuildMI(*MBB, J, dl, + TII->get(PIC16::pagesel)).addExternalSymbol("$"); + Changed = true; + PageChanged = 0; + } + } + + return Changed; } @@ -112,42 +159,74 @@ bool MemSelOpt::processInstruction(MachineInstr *MI) { if (!(TID.isBranch() || TID.isCall() || TID.mayLoad() || TID.mayStore())) return false; + // The first thing we should do is that record if banksel/pagesel are + // changed in an unknown way. This can happend via any type of call. + // We do it here first before scanning of MemOp / BBOp as the indirect + // call insns do not have any operands, but they still may change bank/page. + if (TID.isCall()) { + // Record that we have changed the page, so that we can restore it + // before basic block ends. + // We require to signal that a page anc bank change happened even for + // indirect calls. + PageChanged = 1; + + // When a call is made, there may be banksel for variables in callee. + // Hence the banksel in caller needs to be reset. + CurBank = ""; + } + // Scan for the memory address operand. // FIXME: Should we use standard interfaces like memoperands_iterator, // hasMemOperand() etc ? int MemOpPos = -1; + int BBOpPos = -1; for (unsigned i = 0; i < NumOperands; i++) { MachineOperand Op = MI->getOperand(i); if (Op.getType() == MachineOperand::MO_GlobalAddress || - Op.getType() == MachineOperand::MO_ExternalSymbol || - Op.getType() == MachineOperand::MO_MachineBasicBlock) { + Op.getType() == MachineOperand::MO_ExternalSymbol) { // We found one mem operand. Next one may be BS. MemOpPos = i; - break; + } + if (Op.getType() == MachineOperand::MO_MachineBasicBlock) { + // We found one BB operand. Next one may be pagesel. + BBOpPos = i; } } // If we did not find an insn accessing memory. Continue. - if (MemOpPos == -1) return Changed; + if ((MemOpPos == -1) && + (BBOpPos == -1)) + return false; + assert ((BBOpPos != MemOpPos) && "operand can only be of one type"); - // Get the MemOp. - MachineOperand &Op = MI->getOperand(MemOpPos); // If this is a pagesel material, handle it first. - if (MI->getOpcode() == PIC16::CALL || - MI->getOpcode() == PIC16::br_uncond) { + // CALL and br_ucond insns use MemOp (GA or ES) and not BBOp. + // Pagesel is required only for a direct call. + if ((MI->getOpcode() == PIC16::CALL)) { + // Get the BBOp. + MachineOperand &MemOp = MI->getOperand(MemOpPos); DebugLoc dl = MI->getDebugLoc(); - BuildMI(*MBB, MI, dl, TII->get(PIC16::pagesel)). - addOperand(Op); - return true; + BuildMI(*MBB, MI, dl, TII->get(PIC16::pagesel)).addOperand(MemOp); + + // CALL and br_ucond needs only pagesel. so we are done. + return true; } + // Pagesel is handled. Now, add a Banksel if needed. + if (MemOpPos == -1) return Changed; + // Get the MemOp. + MachineOperand &Op = MI->getOperand(MemOpPos); + // Get the section name(NewBank) for MemOp. // This assumes that the section names for globals are already set by // AsmPrinter->doInitialization. std::string NewBank = CurBank; + bool hasExternalLinkage = false; if (Op.getType() == MachineOperand::MO_GlobalAddress && Op.getGlobal()->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE) { + if (Op.getGlobal()->hasExternalLinkage()) + hasExternalLinkage= true; NewBank = Op.getGlobal()->getSection(); } else if (Op.getType() == MachineOperand::MO_ExternalSymbol) { // External Symbol is generated for temp data and arguments. They are @@ -162,7 +241,7 @@ bool MemSelOpt::processInstruction(MachineInstr *MI) { // If the previous and new section names are same, we don't need to // emit banksel. - if (NewBank.compare(CurBank) != 0 ) { + if (NewBank.compare(CurBank) != 0 || hasExternalLinkage) { DebugLoc dl = MI->getDebugLoc(); BuildMI(*MBB, MI, dl, TII->get(PIC16::banksel)). addOperand(Op);