PrologEpilogInserter.cpp revision 7f7bbc2fdb833485ac3d865a405fd948e58e8ddb
158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner//===-- PrologEpilogInserter.cpp - Insert Prolog/Epilog code in function --===// 2b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 3b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// The LLVM Compiler Infrastructure 4b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 5b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// This file was developed by the LLVM research group and is distributed under 6b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// the University of Illinois Open Source License. See LICENSE.TXT for details. 7b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 8b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell//===----------------------------------------------------------------------===// 958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// 1058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// This pass is responsible for finalizing the functions frame layout, saving 1158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// callee saved registers, and for emitting prolog & epilog code for the 1258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// function. 1358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// 1458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// This pass must be run after register allocation. After this pass is 1558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// executed, it is illegal to construct MO_FrameIndex operands. 1658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner// 1758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner//===----------------------------------------------------------------------===// 1858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 19f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner#include "llvm/CodeGen/Passes.h" 20f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner#include "llvm/CodeGen/MachineFunctionPass.h" 2158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner#include "llvm/CodeGen/MachineInstr.h" 22eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner#include "llvm/CodeGen/MachineFrameInfo.h" 2358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner#include "llvm/Target/TargetMachine.h" 2458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner#include "llvm/Target/MRegisterInfo.h" 258bd66e690779c838db51f55cf0b31d7206b3b659Chris Lattner#include "llvm/Target/TargetFrameInfo.h" 263501feab811c86c9659248a4875fc31a3165f84dChris Lattner#include "llvm/Target/TargetInstrInfo.h" 2705d8350c12d8d81de1d8af6f7da155bc1c1da50eChris Lattnerusing namespace llvm; 28d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 2958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnernamespace { 30f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner struct PEI : public MachineFunctionPass { 31f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner const char *getPassName() const { 32f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner return "Prolog/Epilog Insertion & Frame Finalization"; 3358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 3458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 3558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// runOnMachineFunction - Insert prolog/epilog code and replace abstract 3658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// frame indexes with appropriate references. 3758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// 3858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool runOnMachineFunction(MachineFunction &Fn) { 3958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Scan the function for modified caller saved registers and insert spill 4058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // code for any caller saved registers that are modified. Also calculate 4158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // the MaxCallFrameSize and HasCalls variables for the function's frame 4258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // information and eliminates call frame pseudo instructions. 4358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner saveCallerSavedRegisters(Fn); 4458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 4558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Allow the target machine to make final modifications to the function 4658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // before the frame layout is finalized. 4758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn); 4858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 4958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Calculate actual frame offsets for all of the abstract stack objects... 5058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner calculateFrameObjectOffsets(Fn); 5158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 524ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add prolog and epilog code to the function. 534ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner insertPrologEpilogCode(Fn); 544ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 5558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Replace all MO_FrameIndex operands with physical register references 5658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // and actual offsets. 5758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // 5858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner replaceFrameIndices(Fn); 5958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return true; 6058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 6158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 6258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner private: 6358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void saveCallerSavedRegisters(MachineFunction &Fn); 6458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void calculateFrameObjectOffsets(MachineFunction &Fn); 6558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void replaceFrameIndices(MachineFunction &Fn); 6658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void insertPrologEpilogCode(MachineFunction &Fn); 6758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner }; 6858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 6958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 70d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 7158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// createPrologEpilogCodeInserter - This function returns a pass that inserts 7258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// prolog and epilog code, and eliminates abstract frame references. 7358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 7405d8350c12d8d81de1d8af6f7da155bc1c1da50eChris LattnerFunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); } 7558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 7658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 7758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// saveCallerSavedRegisters - Scan the function for modified caller saved 7858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// registers and insert spill code for any caller saved registers that are 7958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// modified. Also calculate the MaxCallFrameSize and HasCalls variables for 8058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// the function's frame information and eliminates call frame pseudo 8158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// instructions. 8258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 8358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::saveCallerSavedRegisters(MachineFunction &Fn) { 8458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); 859bcdcd17c7219dbc68de2f11ca2de86471c8c390Chris Lattner const TargetFrameInfo &FrameInfo = *Fn.getTarget().getFrameInfo(); 8658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 8758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Get the callee saved register list... 8858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const unsigned *CSRegs = RegInfo->getCalleeSaveRegs(); 8958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 9058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Get the function call frame set-up and tear-down instruction opcode 9158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode(); 9258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode(); 9358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 9458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Early exit for targets which have no callee saved registers and no call 9558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // frame setup/destroy pseudo instructions. 9658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((CSRegs == 0 || CSRegs[0] == 0) && 9758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FrameSetupOpcode == -1 && FrameDestroyOpcode == -1) 9858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return; 9958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 10058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // This bitset contains an entry for each physical register for the target... 101859a18b5833f3566799313ecba8db4916500485bAlkis Evlogimenos std::vector<bool> ModifiedRegs(RegInfo->getNumRegs()); 10258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned MaxCallFrameSize = 0; 10358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool HasCalls = false; 10458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 10558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) 10658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) 107c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos if (I->getOpcode() == FrameSetupOpcode || 108c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos I->getOpcode() == FrameDestroyOpcode) { 109c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos assert(I->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo" 11058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner " instructions should have a single immediate argument!"); 111c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos unsigned Size = I->getOperand(0).getImmedValue(); 11258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (Size > MaxCallFrameSize) MaxCallFrameSize = Size; 11358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner HasCalls = true; 114c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I++); 11558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } else { 116c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { 117c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos MachineOperand &MO = I->getOperand(i); 1181cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner if (MO.isRegister() && MO.isDef()) { 1191cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner assert(MRegisterInfo::isPhysicalRegister(MO.getReg()) && 1201cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner "Register allocation must be performed!"); 12158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner ModifiedRegs[MO.getReg()] = true; // Register is modified 1221cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner } 1231cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner } 12458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner ++I; 12558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 12658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 127eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner MachineFrameInfo *FFI = Fn.getFrameInfo(); 12858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setHasCalls(HasCalls); 12958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setMaxCallFrameSize(MaxCallFrameSize); 13058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 13158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now figure out which *callee saved* registers are modified by the current 13258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // function, thus needing to be saved and restored in the prolog/epilog. 13358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // 13458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<unsigned> RegsToSave; 13558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0; CSRegs[i]; ++i) { 13658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Reg = CSRegs[i]; 13758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (ModifiedRegs[Reg]) { 13858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegsToSave.push_back(Reg); // If modified register... 13973ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } else { 14073ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg); 14173ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos *AliasSet; ++AliasSet) { // Check alias registers too... 14273ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos if (ModifiedRegs[*AliasSet]) { 14358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegsToSave.push_back(Reg); 14458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner break; 14558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 14673ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } 14773ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } 14858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 14958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 15058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (RegsToSave.empty()) 15158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return; // Early exit if no caller saved registers are modified! 15258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 15358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now that we know which registers need to be saved and restored, allocate 15458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // stack slots for them. 15558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<int> StackSlots; 15658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 157f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner int FrameIdx = FFI->CreateStackObject(RegInfo->getRegClass(RegsToSave[i])); 15858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner StackSlots.push_back(FrameIdx); 15958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 16058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 16158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now that we have a stack slot for each register to be saved, insert spill 16258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // code into the entry block... 16358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineBasicBlock *MBB = Fn.begin(); 16458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineBasicBlock::iterator I = MBB->begin(); 16558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 16658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]); 16758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 16858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Insert the spill to the stack frame... 16958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i], RC); 17058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 17158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 17258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Add code to restore the callee-save registers in each exiting block. 1739bcdcd17c7219dbc68de2f11ca2de86471c8c390Chris Lattner const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); 17458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI) { 17558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // If last instruction is a return instruction, add an epilogue 176c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos if (!FI->empty() && TII.isReturn(FI->back().getOpcode())) { 177c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos MBB = FI; 178c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos I = MBB->end(); --I; 17958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 18058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 18158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]); 18258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i],StackSlots[i], RC); 18358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner --I; // Insert in reverse order 18458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 18558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 18658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 18758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 18858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 18958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 19058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the 19158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// abstract stack objects... 19258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 19358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { 1949bcdcd17c7219dbc68de2f11ca2de86471c8c390Chris Lattner const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo(); 19558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 19658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool StackGrowsDown = 19758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown; 19858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 19958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Loop over all of the stack objects, assigning sequential addresses... 200eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner MachineFrameInfo *FFI = Fn.getFrameInfo(); 20158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 202f85249ca7336cda5bd491c161cb163847774e868Chris Lattner unsigned StackAlignment = TFI.getStackAlignment(); 20378d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner 20405d8350c12d8d81de1d8af6f7da155bc1c1da50eChris Lattner // Start at the beginning of the local area. 205577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // The Offset is the distance from the stack top in the direction 206577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // of stack growth -- so it's always positive. 2074ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner int Offset = TFI.getOffsetOfLocalArea(); 208577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner if (StackGrowsDown) 2097f7bbc2fdb833485ac3d865a405fd948e58e8ddbChris Lattner Offset = -Offset; 210577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner assert(Offset >= 0 211577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner && "Local area offset should be in direction of stack growth"); 212577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner 213577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // If there are fixed sized objects that are preallocated in the local area, 214577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // non-fixed objects can't be allocated right at the start of local area. 215577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // We currently don't support filling in holes in between fixed sized objects, 216577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // so we adjust 'Offset' to point to the end of last fixed sized 21705d8350c12d8d81de1d8af6f7da155bc1c1da50eChris Lattner // preallocated object. 21805d8350c12d8d81de1d8af6f7da155bc1c1da50eChris Lattner for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) { 219577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner int FixedOff; 220577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner if (StackGrowsDown) { 221577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // The maximum distance from the stack pointer is at lower address of 222577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // the object -- which is given by offset. For down growing stack 223577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // the offset is negative, so we negate the offset to get the distance. 224577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner FixedOff = -FFI->getObjectOffset(i); 225577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner } else { 226577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // The maximum distance from the start pointer is at the upper 227577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // address of the object. 228577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i); 229577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner } 230577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner if (FixedOff > Offset) Offset = FixedOff; 23105d8350c12d8d81de1d8af6f7da155bc1c1da50eChris Lattner } 23205d8350c12d8d81de1d8af6f7da155bc1c1da50eChris Lattner 23358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) { 234577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // If stack grows down, we need to add size of find the lowest 235577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner // address of the object. 236577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner if (StackGrowsDown) 237577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner Offset += FFI->getObjectSize(i); 23858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 23958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Align = FFI->getObjectAlignment(i); 240f85249ca7336cda5bd491c161cb163847774e868Chris Lattner assert(Align <= StackAlignment && "Cannot align stack object to higher " 24178d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner "alignment boundary than the stack itself!"); 24258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Offset = (Offset+Align-1)/Align*Align; // Adjust to Alignment boundary... 24358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 244577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner if (StackGrowsDown) { 245577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner FFI->setObjectOffset(i, -Offset); // Set the computed offset 246577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner } else { 247577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner FFI->setObjectOffset(i, Offset); 248577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner Offset += FFI->getObjectSize(i); 249577aec14288b86ab1fb07e164375ebc7d3038cb7Chris Lattner } 25058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 25158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 25293799292c1c04c53ff077a427737b3ffbd0445abChris Lattner // Align the final stack pointer offset, but only if there are calls in the 25393799292c1c04c53ff077a427737b3ffbd0445abChris Lattner // function. This ensures that any calls to subroutines have their stack 25493799292c1c04c53ff077a427737b3ffbd0445abChris Lattner // frames suitable aligned. 25593799292c1c04c53ff077a427737b3ffbd0445abChris Lattner if (FFI->hasCalls()) 25693799292c1c04c53ff077a427737b3ffbd0445abChris Lattner Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment; 25758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 25858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Set the final value of the stack pointer... 2597f7bbc2fdb833485ac3d865a405fd948e58e8ddbChris Lattner FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea()); 2604ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner} 2614ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2624ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2634ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// insertPrologEpilogCode - Scan the function for modified caller saved 2644ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// registers, insert spill code for these caller saved registers, then add 2654ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// prolog and epilog code to the function. 2664ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// 2674ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattnervoid PEI::insertPrologEpilogCode(MachineFunction &Fn) { 2684ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add prologue to the function... 2694ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner Fn.getTarget().getRegisterInfo()->emitPrologue(Fn); 2704ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2714ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add epilogue to restore the callee-save registers in each exiting block 2729bcdcd17c7219dbc68de2f11ca2de86471c8c390Chris Lattner const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); 2734ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) { 2744ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // If last instruction is a return instruction, add an epilogue 275c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos if (!I->empty() && TII.isReturn(I->back().getOpcode())) 2764ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I); 2774ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner } 27858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 27958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 28058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 28158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical 28258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// register references and actual offsets. 28358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 28458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::replaceFrameIndices(MachineFunction &Fn) { 28558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do? 28658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 28758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetMachine &TM = Fn.getTarget(); 28858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!"); 28958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const MRegisterInfo &MRI = *TM.getRegisterInfo(); 29058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 29158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) 29258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) 293c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 294c0b9dc5be79f009d260edb5cd5e1d8346587aaa2Alkis Evlogimenos if (I->getOperand(i).isFrameIndex()) { 29558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // If this instruction has a FrameIndex operand, we need to use that 29658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // target machine register info object to eliminate it. 29758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MRI.eliminateFrameIndex(Fn, I); 29858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner break; 29958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 30058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 301