PrologEpilogInserter.cpp revision 73ff5120eb8b8c0ccbfed8a17f1024c67a75f319
158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner//===-- PrologEpilogInserter.cpp - Insert Prolog/Epilog code in function --===// 258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// 358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// This pass is responsible for finalizing the functions frame layout, saving 458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// callee saved registers, and for emitting prolog & epilog code for the 558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// function. 658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// 758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// This pass must be run after register allocation. After this pass is 858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// executed, it is illegal to construct MO_FrameIndex operands. 958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// 1058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner//===----------------------------------------------------------------------===// 1158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 12f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner#include "llvm/CodeGen/Passes.h" 13f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner#include "llvm/CodeGen/MachineFunctionPass.h" 1458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner#include "llvm/CodeGen/MachineInstr.h" 15eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner#include "llvm/CodeGen/MachineFrameInfo.h" 1658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner#include "llvm/Target/TargetMachine.h" 1758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner#include "llvm/Target/MRegisterInfo.h" 188bd66e690779c838db51f55cf0b31d7206b3b659Chris Lattner#include "llvm/Target/TargetFrameInfo.h" 193501feab811c86c9659248a4875fc31a3165f84dChris Lattner#include "llvm/Target/TargetInstrInfo.h" 2058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 2158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnernamespace { 22f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner struct PEI : public MachineFunctionPass { 23f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner const char *getPassName() const { 24f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner return "Prolog/Epilog Insertion & Frame Finalization"; 2558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 2658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 2758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// runOnMachineFunction - Insert prolog/epilog code and replace abstract 2858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// frame indexes with appropriate references. 2958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// 3058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool runOnMachineFunction(MachineFunction &Fn) { 3158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Scan the function for modified caller saved registers and insert spill 3258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // code for any caller saved registers that are modified. Also calculate 3358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // the MaxCallFrameSize and HasCalls variables for the function's frame 3458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // information and eliminates call frame pseudo instructions. 3558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner saveCallerSavedRegisters(Fn); 3658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 3758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Allow the target machine to make final modifications to the function 3858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // before the frame layout is finalized. 3958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn); 4058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 4158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Calculate actual frame offsets for all of the abstract stack objects... 4258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner calculateFrameObjectOffsets(Fn); 4358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 444ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add prolog and epilog code to the function. 454ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner insertPrologEpilogCode(Fn); 464ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 4758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Replace all MO_FrameIndex operands with physical register references 4858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // and actual offsets. 4958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // 5058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner replaceFrameIndices(Fn); 5158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return true; 5258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 5358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 5458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner private: 5558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void saveCallerSavedRegisters(MachineFunction &Fn); 5658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void calculateFrameObjectOffsets(MachineFunction &Fn); 5758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void replaceFrameIndices(MachineFunction &Fn); 5858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void insertPrologEpilogCode(MachineFunction &Fn); 5958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner }; 6058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 6158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 6258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// createPrologEpilogCodeInserter - This function returns a pass that inserts 6358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// prolog and epilog code, and eliminates abstract frame references. 6458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 6519df3876e6dce016ec4c5ab28320a246ab285001Brian GaekeFunctionPass *createPrologEpilogCodeInserter() { return new PEI(); } 6658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 6758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 6858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// saveCallerSavedRegisters - Scan the function for modified caller saved 6958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// registers and insert spill code for any caller saved registers that are 7058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// modified. Also calculate the MaxCallFrameSize and HasCalls variables for 7158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// the function's frame information and eliminates call frame pseudo 7258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// instructions. 7358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 7458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::saveCallerSavedRegisters(MachineFunction &Fn) { 7558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); 7658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetFrameInfo &FrameInfo = Fn.getTarget().getFrameInfo(); 7758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 7858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Get the callee saved register list... 7958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const unsigned *CSRegs = RegInfo->getCalleeSaveRegs(); 8058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 8158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Get the function call frame set-up and tear-down instruction opcode 8258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode(); 8358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode(); 8458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 8558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Early exit for targets which have no callee saved registers and no call 8658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // frame setup/destroy pseudo instructions. 8758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((CSRegs == 0 || CSRegs[0] == 0) && 8858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FrameSetupOpcode == -1 && FrameDestroyOpcode == -1) 8958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return; 9058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 9158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // This bitset contains an entry for each physical register for the target... 9258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<bool> ModifiedRegs(MRegisterInfo::FirstVirtualRegister); 9358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned MaxCallFrameSize = 0; 9458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool HasCalls = false; 9558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 9658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) 9758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) 9858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((*I)->getOpcode() == FrameSetupOpcode || 9958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner (*I)->getOpcode() == FrameDestroyOpcode) { 10058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert((*I)->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo" 10158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner " instructions should have a single immediate argument!"); 10258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Size = (*I)->getOperand(0).getImmedValue(); 10358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (Size > MaxCallFrameSize) MaxCallFrameSize = Size; 10458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner HasCalls = true; 10558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I); 10658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } else { 10758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = (*I)->getNumOperands(); i != e; ++i) { 10858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineOperand &MO = (*I)->getOperand(i); 10958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert(!MO.isVirtualRegister() && 11058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner "Register allocation must be performed!"); 1115f2180c53330502eb2f0f5bf3f21a838ad800906Vikram S. Adve if (MO.isPhysicalRegister() && 1125f2180c53330502eb2f0f5bf3f21a838ad800906Vikram S. Adve (MO.opIsDefOnly() || MO.opIsDefAndUse())) 11358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner ModifiedRegs[MO.getReg()] = true; // Register is modified 11458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 11558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner ++I; 11658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 11758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 118eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner MachineFrameInfo *FFI = Fn.getFrameInfo(); 11958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setHasCalls(HasCalls); 12058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setMaxCallFrameSize(MaxCallFrameSize); 12158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 12258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now figure out which *callee saved* registers are modified by the current 12358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // function, thus needing to be saved and restored in the prolog/epilog. 12458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // 12558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<unsigned> RegsToSave; 12658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0; CSRegs[i]; ++i) { 12758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Reg = CSRegs[i]; 12858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (ModifiedRegs[Reg]) { 12958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegsToSave.push_back(Reg); // If modified register... 13073ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } else { 13173ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg); 13273ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos *AliasSet; ++AliasSet) { // Check alias registers too... 13373ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos if (ModifiedRegs[*AliasSet]) { 13458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegsToSave.push_back(Reg); 13558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner break; 13658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 13773ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } 13873ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } 13958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 14058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 14158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (RegsToSave.empty()) 14258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return; // Early exit if no caller saved registers are modified! 14358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 14458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now that we know which registers need to be saved and restored, allocate 14558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // stack slots for them. 14658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<int> StackSlots; 14758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 148f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner int FrameIdx = FFI->CreateStackObject(RegInfo->getRegClass(RegsToSave[i])); 14958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner StackSlots.push_back(FrameIdx); 15058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 15158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 15258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now that we have a stack slot for each register to be saved, insert spill 15358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // code into the entry block... 15458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineBasicBlock *MBB = Fn.begin(); 15558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineBasicBlock::iterator I = MBB->begin(); 15658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 15758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]); 15858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 15958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Insert the spill to the stack frame... 16058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i], RC); 16158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 16258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 16358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Add code to restore the callee-save registers in each exiting block. 1643501feab811c86c9659248a4875fc31a3165f84dChris Lattner const TargetInstrInfo &TII = Fn.getTarget().getInstrInfo(); 16558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI) { 16658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // If last instruction is a return instruction, add an epilogue 167b589bf7d77a57e961a871ae5ffee2381722d8c0fChris Lattner if (!FI->empty() && TII.isReturn(FI->back()->getOpcode())) { 16858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MBB = FI; I = MBB->end()-1; 16958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 17058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 17158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]); 17258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i],StackSlots[i], RC); 17358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner --I; // Insert in reverse order 17458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 17558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 17658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 17758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 17858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 17958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 18058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the 18158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// abstract stack objects... 18258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 18358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { 18458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetFrameInfo &TFI = Fn.getTarget().getFrameInfo(); 18558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 18658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool StackGrowsDown = 18758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown; 18858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert(StackGrowsDown && "Only tested on stack down growing targets!"); 18958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 19058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Loop over all of the stack objects, assigning sequential addresses... 191eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner MachineFrameInfo *FFI = Fn.getFrameInfo(); 19258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 193f85249ca7336cda5bd491c161cb163847774e868Chris Lattner unsigned StackAlignment = TFI.getStackAlignment(); 19478d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner 19558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Start at the beginning of the local area... 1964ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner int Offset = TFI.getOffsetOfLocalArea(); 19758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) { 19858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Offset += FFI->getObjectSize(i); // Allocate Size bytes... 19958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 20058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Align = FFI->getObjectAlignment(i); 201f85249ca7336cda5bd491c161cb163847774e868Chris Lattner assert(Align <= StackAlignment && "Cannot align stack object to higher " 20278d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner "alignment boundary than the stack itself!"); 20358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Offset = (Offset+Align-1)/Align*Align; // Adjust to Alignment boundary... 20458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 20558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setObjectOffset(i, -Offset); // Set the computed offset 20658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 20758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 20858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Align the final stack pointer offset... 20978d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment; 21058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 21158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Set the final value of the stack pointer... 2124ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner FFI->setStackSize(Offset-TFI.getOffsetOfLocalArea()); 2134ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner} 2144ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2154ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2164ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// insertPrologEpilogCode - Scan the function for modified caller saved 2174ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// registers, insert spill code for these caller saved registers, then add 2184ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// prolog and epilog code to the function. 2194ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// 2204ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattnervoid PEI::insertPrologEpilogCode(MachineFunction &Fn) { 2214ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add prologue to the function... 2224ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner Fn.getTarget().getRegisterInfo()->emitPrologue(Fn); 2234ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2244ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add epilogue to restore the callee-save registers in each exiting block 2254ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner const TargetInstrInfo &TII = Fn.getTarget().getInstrInfo(); 2264ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) { 2274ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // If last instruction is a return instruction, add an epilogue 2280416d2a70aea644c3e0c06301c29f3b81ec1e42dChris Lattner if (!I->empty() && TII.isReturn(I->back()->getOpcode())) 2294ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I); 2304ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner } 23158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 23258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 23358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 23458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical 23558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// register references and actual offsets. 23658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 23758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::replaceFrameIndices(MachineFunction &Fn) { 23858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do? 23958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 24058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetMachine &TM = Fn.getTarget(); 24158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!"); 24258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const MRegisterInfo &MRI = *TM.getRegisterInfo(); 24358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 24458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) 24558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) 24658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = (*I)->getNumOperands(); i != e; ++i) 24758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((*I)->getOperand(i).isFrameIndex()) { 24858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // If this instruction has a FrameIndex operand, we need to use that 24958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // target machine register info object to eliminate it. 25058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MRI.eliminateFrameIndex(Fn, I); 25158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner break; 25258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 25358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 254