PrologEpilogInserter.cpp revision 1cbe4d0ad0888e50858cca83cf2a0d3083709513
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" 2758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 28d0fde30ce850b78371fd1386338350591f9ff494Brian Gaekenamespace llvm { 29d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 3058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnernamespace { 31f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner struct PEI : public MachineFunctionPass { 32f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner const char *getPassName() const { 33f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner return "Prolog/Epilog Insertion & Frame Finalization"; 3458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 3558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 3658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// runOnMachineFunction - Insert prolog/epilog code and replace abstract 3758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// frame indexes with appropriate references. 3858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner /// 3958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool runOnMachineFunction(MachineFunction &Fn) { 4058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Scan the function for modified caller saved registers and insert spill 4158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // code for any caller saved registers that are modified. Also calculate 4258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // the MaxCallFrameSize and HasCalls variables for the function's frame 4358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // information and eliminates call frame pseudo instructions. 4458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner saveCallerSavedRegisters(Fn); 4558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 4658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Allow the target machine to make final modifications to the function 4758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // before the frame layout is finalized. 4858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn); 4958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 5058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Calculate actual frame offsets for all of the abstract stack objects... 5158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner calculateFrameObjectOffsets(Fn); 5258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 534ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add prolog and epilog code to the function. 544ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner insertPrologEpilogCode(Fn); 554ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 5658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Replace all MO_FrameIndex operands with physical register references 5758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // and actual offsets. 5858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // 5958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner replaceFrameIndices(Fn); 6058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return true; 6158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 6258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 6358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner private: 6458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void saveCallerSavedRegisters(MachineFunction &Fn); 6558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void calculateFrameObjectOffsets(MachineFunction &Fn); 6658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void replaceFrameIndices(MachineFunction &Fn); 6758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner void insertPrologEpilogCode(MachineFunction &Fn); 6858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner }; 6958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 7058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 71d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 7258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// createPrologEpilogCodeInserter - This function returns a pass that inserts 7358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// prolog and epilog code, and eliminates abstract frame references. 7458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 7519df3876e6dce016ec4c5ab28320a246ab285001Brian GaekeFunctionPass *createPrologEpilogCodeInserter() { return new PEI(); } 7658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 7758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 7858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// saveCallerSavedRegisters - Scan the function for modified caller saved 7958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// registers and insert spill code for any caller saved registers that are 8058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// modified. Also calculate the MaxCallFrameSize and HasCalls variables for 8158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// the function's frame information and eliminates call frame pseudo 8258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// instructions. 8358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 8458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::saveCallerSavedRegisters(MachineFunction &Fn) { 8558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); 8658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetFrameInfo &FrameInfo = Fn.getTarget().getFrameInfo(); 8758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 8858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Get the callee saved register list... 8958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const unsigned *CSRegs = RegInfo->getCalleeSaveRegs(); 9058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 9158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Get the function call frame set-up and tear-down instruction opcode 9258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode(); 9358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode(); 9458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 9558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Early exit for targets which have no callee saved registers and no call 9658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // frame setup/destroy pseudo instructions. 9758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((CSRegs == 0 || CSRegs[0] == 0) && 9858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FrameSetupOpcode == -1 && FrameDestroyOpcode == -1) 9958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return; 10058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 10158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // This bitset contains an entry for each physical register for the target... 10258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<bool> ModifiedRegs(MRegisterInfo::FirstVirtualRegister); 10358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned MaxCallFrameSize = 0; 10458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool HasCalls = false; 10558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 10658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) 10758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) 10858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((*I)->getOpcode() == FrameSetupOpcode || 10958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner (*I)->getOpcode() == FrameDestroyOpcode) { 11058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert((*I)->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo" 11158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner " instructions should have a single immediate argument!"); 11258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Size = (*I)->getOperand(0).getImmedValue(); 11358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (Size > MaxCallFrameSize) MaxCallFrameSize = Size; 11458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner HasCalls = true; 11558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I); 11658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } else { 11758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = (*I)->getNumOperands(); i != e; ++i) { 11858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineOperand &MO = (*I)->getOperand(i); 1191cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner if (MO.isRegister() && MO.isDef()) { 1201cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner assert(MRegisterInfo::isPhysicalRegister(MO.getReg()) && 1211cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner "Register allocation must be performed!"); 12258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner ModifiedRegs[MO.getReg()] = true; // Register is modified 1231cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner } 1241cbe4d0ad0888e50858cca83cf2a0d3083709513Chris Lattner } 12558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner ++I; 12658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 12758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 128eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner MachineFrameInfo *FFI = Fn.getFrameInfo(); 12958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setHasCalls(HasCalls); 13058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setMaxCallFrameSize(MaxCallFrameSize); 13158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 13258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now figure out which *callee saved* registers are modified by the current 13358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // function, thus needing to be saved and restored in the prolog/epilog. 13458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // 13558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<unsigned> RegsToSave; 13658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0; CSRegs[i]; ++i) { 13758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Reg = CSRegs[i]; 13858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (ModifiedRegs[Reg]) { 13958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegsToSave.push_back(Reg); // If modified register... 14073ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } else { 14173ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg); 14273ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos *AliasSet; ++AliasSet) { // Check alias registers too... 14373ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos if (ModifiedRegs[*AliasSet]) { 14458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegsToSave.push_back(Reg); 14558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner break; 14658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 14773ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } 14873ff5120eb8b8c0ccbfed8a17f1024c67a75f319Alkis Evlogimenos } 14958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 15058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 15158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (RegsToSave.empty()) 15258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner return; // Early exit if no caller saved registers are modified! 15358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 15458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now that we know which registers need to be saved and restored, allocate 15558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // stack slots for them. 15658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner std::vector<int> StackSlots; 15758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 158f00a3f905e8cd99ab4d3dbbde1a9d510516e0fa2Chris Lattner int FrameIdx = FFI->CreateStackObject(RegInfo->getRegClass(RegsToSave[i])); 15958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner StackSlots.push_back(FrameIdx); 16058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 16158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 16258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Now that we have a stack slot for each register to be saved, insert spill 16358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // code into the entry block... 16458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineBasicBlock *MBB = Fn.begin(); 16558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MachineBasicBlock::iterator I = MBB->begin(); 16658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { 16758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]); 16858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 16958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Insert the spill to the stack frame... 17058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i], RC); 17158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 17258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 17358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Add code to restore the callee-save registers in each exiting block. 1743501feab811c86c9659248a4875fc31a3165f84dChris Lattner const TargetInstrInfo &TII = Fn.getTarget().getInstrInfo(); 17558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI) { 17658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // If last instruction is a return instruction, add an epilogue 177b589bf7d77a57e961a871ae5ffee2381722d8c0fChris Lattner if (!FI->empty() && TII.isReturn(FI->back()->getOpcode())) { 17858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MBB = FI; I = MBB->end()-1; 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) { 19458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetFrameInfo &TFI = Fn.getTarget().getFrameInfo(); 19558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 19658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner bool StackGrowsDown = 19758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown; 19858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert(StackGrowsDown && "Only tested on stack down growing targets!"); 19958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 20058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Loop over all of the stack objects, assigning sequential addresses... 201eb24db9727a7babe863d5afe70c7bda3a460da18Chris Lattner MachineFrameInfo *FFI = Fn.getFrameInfo(); 20258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 203f85249ca7336cda5bd491c161cb163847774e868Chris Lattner unsigned StackAlignment = TFI.getStackAlignment(); 20478d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner 20558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Start at the beginning of the local area... 2064ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner int Offset = TFI.getOffsetOfLocalArea(); 20758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) { 20858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Offset += FFI->getObjectSize(i); // Allocate Size bytes... 20958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 21058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner unsigned Align = FFI->getObjectAlignment(i); 211f85249ca7336cda5bd491c161cb163847774e868Chris Lattner assert(Align <= StackAlignment && "Cannot align stack object to higher " 21278d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner "alignment boundary than the stack itself!"); 21358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner Offset = (Offset+Align-1)/Align*Align; // Adjust to Alignment boundary... 21458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 21558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner FFI->setObjectOffset(i, -Offset); // Set the computed offset 21658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 21758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 21858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Align the final stack pointer offset... 21978d6db5627bdf41ab3ffd96133821647dbc60d53Chris Lattner Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment; 22058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 22158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // Set the final value of the stack pointer... 2224ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner FFI->setStackSize(Offset-TFI.getOffsetOfLocalArea()); 2234ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner} 2244ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2254ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2264ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// insertPrologEpilogCode - Scan the function for modified caller saved 2274ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// registers, insert spill code for these caller saved registers, then add 2284ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// prolog and epilog code to the function. 2294ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner/// 2304ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattnervoid PEI::insertPrologEpilogCode(MachineFunction &Fn) { 2314ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add prologue to the function... 2324ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner Fn.getTarget().getRegisterInfo()->emitPrologue(Fn); 2334ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner 2344ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // Add epilogue to restore the callee-save registers in each exiting block 2354ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner const TargetInstrInfo &TII = Fn.getTarget().getInstrInfo(); 2364ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) { 2374ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner // If last instruction is a return instruction, add an epilogue 2380416d2a70aea644c3e0c06301c29f3b81ec1e42dChris Lattner if (!I->empty() && TII.isReturn(I->back()->getOpcode())) 2394ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I); 2404ac7d7302b36a5d20f71b5c290c63a7f6c345289Chris Lattner } 24158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 24258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 24358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 24458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical 24558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// register references and actual offsets. 24658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner/// 24758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattnervoid PEI::replaceFrameIndices(MachineFunction &Fn) { 24858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do? 24958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 25058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const TargetMachine &TM = Fn.getTarget(); 25158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!"); 25258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner const MRegisterInfo &MRI = *TM.getRegisterInfo(); 25358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner 25458b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) 25558b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) 25658b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner for (unsigned i = 0, e = (*I)->getNumOperands(); i != e; ++i) 25758b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner if ((*I)->getOperand(i).isFrameIndex()) { 25858b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // If this instruction has a FrameIndex operand, we need to use that 25958b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner // target machine register info object to eliminate it. 26058b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner MRI.eliminateFrameIndex(Fn, I); 26158b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner break; 26258b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner } 26358b3328ac709a5706a8bfa522012ed90f1b4d4bdChris Lattner} 264d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 265d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke} // End llvm namespace 266