/// insertCSRSpillsAndRestores - Insert spill and restore code for /// callee saved registers used in the function, handling shrink wrapping. /// void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) { // Get callee saved register information. MachineFrameInfo *MFI = Fn.getFrameInfo(); const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); MFI->setCalleeSavedInfoValid(true); // Early exit if no callee saved registers are modified! if (CSI.empty()) return; const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering(); const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo(); MachineBasicBlock::iterator I; if (! ShrinkWrapThisFunction) { // Spill using target interface. I = EntryBlock->begin(); if (!TFI->spillCalleeSavedRegisters(*EntryBlock, I, CSI, TRI)) { for (unsigned i = 0, e = CSI.size(); i != e; ++i) { // Add the callee-saved register as live-in. // It's killed at the spill. EntryBlock->addLiveIn(CSI[i].getReg()); // Insert the spill to the stack frame. unsigned Reg = CSI[i].getReg(); const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.storeRegToStackSlot(*EntryBlock, I, Reg, true, CSI[i].getFrameIdx(), RC, TRI); } } // Restore using target interface. for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri) { MachineBasicBlock* MBB = ReturnBlocks[ri]; I = MBB->end(); --I; // Skip over all terminator instructions, which are part of the return // sequence. MachineBasicBlock::iterator I2 = I; while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator()) I = I2; bool AtStart = I == MBB->begin(); MachineBasicBlock::iterator BeforeI = I; if (!AtStart) --BeforeI; // Restore all registers immediately before the return and any // terminators that precede it. if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) { for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.loadRegFromStackSlot(*MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI); assert(I != MBB->begin() && "loadRegFromStackSlot didn't insert any code!"); // Insert in reverse order. loadRegFromStackSlot can insert // multiple instructions. if (AtStart) I = MBB->begin(); else { I = BeforeI; ++I; } } } } return; } // Insert spills. std::vector<CalleeSavedInfo> blockCSI; for (CSRegBlockMap::iterator BI = CSRSave.begin(), BE = CSRSave.end(); BI != BE; ++BI) { MachineBasicBlock* MBB = BI->first; CSRegSet save = BI->second; if (save.empty()) continue; blockCSI.clear(); for (CSRegSet::iterator RI = save.begin(), RE = save.end(); RI != RE; ++RI) { blockCSI.push_back(CSI[*RI]); } assert(blockCSI.size() > 0 && "Could not collect callee saved register info"); I = MBB->begin(); // When shrink wrapping, use stack slot stores/loads. for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) { // Add the callee-saved register as live-in. // It's killed at the spill. MBB->addLiveIn(blockCSI[i].getReg()); // Insert the spill to the stack frame. unsigned Reg = blockCSI[i].getReg(); const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.storeRegToStackSlot(*MBB, I, Reg, true, blockCSI[i].getFrameIdx(), RC, TRI); } } for (CSRegBlockMap::iterator BI = CSRRestore.begin(), BE = CSRRestore.end(); BI != BE; ++BI) { MachineBasicBlock* MBB = BI->first; CSRegSet restore = BI->second; if (restore.empty()) continue; blockCSI.clear(); for (CSRegSet::iterator RI = restore.begin(), RE = restore.end(); RI != RE; ++RI) { blockCSI.push_back(CSI[*RI]); } assert(blockCSI.size() > 0 && "Could not find callee saved register info"); // If MBB is empty and needs restores, insert at the _beginning_. if (MBB->empty()) { I = MBB->begin(); } else { I = MBB->end(); --I; // Skip over all terminator instructions, which are part of the // return sequence. if (! I->getDesc().isTerminator()) { ++I; } else { MachineBasicBlock::iterator I2 = I; while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator()) I = I2; } } bool AtStart = I == MBB->begin(); MachineBasicBlock::iterator BeforeI = I; if (!AtStart) --BeforeI; // Restore all registers immediately before the return and any // terminators that precede it. for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) { unsigned Reg = blockCSI[i].getReg(); const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.loadRegFromStackSlot(*MBB, I, Reg, blockCSI[i].getFrameIdx(), RC, TRI); assert(I != MBB->begin() && "loadRegFromStackSlot didn't insert any code!"); // Insert in reverse order. loadRegFromStackSlot can insert // multiple instructions. if (AtStart) I = MBB->begin(); else { I = BeforeI; ++I; } } } }
/// insertCSRSpillsAndRestores - Insert spill and restore code for /// callee saved registers used in the function. /// void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) { // Get callee saved register information. MachineFrameInfo *MFI = Fn.getFrameInfo(); const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); MFI->setCalleeSavedInfoValid(true); // Early exit if no callee saved registers are modified! if (CSI.empty()) return; const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo(); const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering(); const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo(); MachineBasicBlock::iterator I; // Spill using target interface. I = SaveBlock->begin(); if (!TFI->spillCalleeSavedRegisters(*SaveBlock, I, CSI, TRI)) { for (unsigned i = 0, e = CSI.size(); i != e; ++i) { // Insert the spill to the stack frame. unsigned Reg = CSI[i].getReg(); const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.storeRegToStackSlot(*SaveBlock, I, Reg, true, CSI[i].getFrameIdx(), RC, TRI); } } // Update the live-in information of all the blocks up to the save point. updateLiveness(Fn); // Restore using target interface. for (MachineBasicBlock *MBB : RestoreBlocks) { I = MBB->end(); // Skip over all terminator instructions, which are part of the return // sequence. MachineBasicBlock::iterator I2 = I; while (I2 != MBB->begin() && (--I2)->isTerminator()) I = I2; bool AtStart = I == MBB->begin(); MachineBasicBlock::iterator BeforeI = I; if (!AtStart) --BeforeI; // Restore all registers immediately before the return and any // terminators that precede it. if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) { for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.loadRegFromStackSlot(*MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI); assert(I != MBB->begin() && "loadRegFromStackSlot didn't insert any code!"); // Insert in reverse order. loadRegFromStackSlot can insert // multiple instructions. if (AtStart) I = MBB->begin(); else { I = BeforeI; ++I; } } } } }