Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 1 | //===-- PrologEpilogInserter.cpp - Insert Prolog/Epilog code in function --===// |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file was developed by the LLVM research group and is distributed under |
| 6 | // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 9 | // |
| 10 | // This pass is responsible for finalizing the functions frame layout, saving |
| 11 | // callee saved registers, and for emitting prolog & epilog code for the |
| 12 | // function. |
| 13 | // |
| 14 | // This pass must be run after register allocation. After this pass is |
| 15 | // executed, it is illegal to construct MO_FrameIndex operands. |
| 16 | // |
| 17 | //===----------------------------------------------------------------------===// |
| 18 | |
Chris Lattner | f00a3f9 | 2003-01-13 00:23:41 +0000 | [diff] [blame] | 19 | #include "llvm/CodeGen/Passes.h" |
| 20 | #include "llvm/CodeGen/MachineFunctionPass.h" |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 21 | #include "llvm/CodeGen/MachineInstr.h" |
Chris Lattner | eb24db9 | 2002-12-28 21:08:26 +0000 | [diff] [blame] | 22 | #include "llvm/CodeGen/MachineFrameInfo.h" |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 23 | #include "llvm/Target/TargetMachine.h" |
| 24 | #include "llvm/Target/MRegisterInfo.h" |
Chris Lattner | 8bd66e6 | 2002-12-28 21:00:25 +0000 | [diff] [blame] | 25 | #include "llvm/Target/TargetFrameInfo.h" |
Chris Lattner | 3501fea | 2003-01-14 22:00:31 +0000 | [diff] [blame] | 26 | #include "llvm/Target/TargetInstrInfo.h" |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 27 | using namespace llvm; |
Brian Gaeke | d0fde30 | 2003-11-11 22:41:34 +0000 | [diff] [blame] | 28 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 29 | namespace { |
Chris Lattner | f00a3f9 | 2003-01-13 00:23:41 +0000 | [diff] [blame] | 30 | struct PEI : public MachineFunctionPass { |
| 31 | const char *getPassName() const { |
| 32 | return "Prolog/Epilog Insertion & Frame Finalization"; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 33 | } |
| 34 | |
| 35 | /// runOnMachineFunction - Insert prolog/epilog code and replace abstract |
| 36 | /// frame indexes with appropriate references. |
| 37 | /// |
| 38 | bool runOnMachineFunction(MachineFunction &Fn) { |
| 39 | // Scan the function for modified caller saved registers and insert spill |
| 40 | // code for any caller saved registers that are modified. Also calculate |
| 41 | // the MaxCallFrameSize and HasCalls variables for the function's frame |
| 42 | // information and eliminates call frame pseudo instructions. |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 43 | calculateCallerSavedRegisters(Fn); |
| 44 | |
| 45 | // Add the code to save and restore the caller saved registers |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 46 | saveCallerSavedRegisters(Fn); |
| 47 | |
| 48 | // Allow the target machine to make final modifications to the function |
| 49 | // before the frame layout is finalized. |
| 50 | Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn); |
| 51 | |
| 52 | // Calculate actual frame offsets for all of the abstract stack objects... |
| 53 | calculateFrameObjectOffsets(Fn); |
| 54 | |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 55 | // Add prolog and epilog code to the function. This function is required |
| 56 | // to align the stack frame as necessary for any stack variables or |
| 57 | // called functions. Because of this, calculateCallerSavedRegisters |
| 58 | // must be called before this function in order to set the HasCalls |
| 59 | // and MaxCallFrameSize variables. |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 60 | insertPrologEpilogCode(Fn); |
| 61 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 62 | // Replace all MO_FrameIndex operands with physical register references |
| 63 | // and actual offsets. |
| 64 | // |
| 65 | replaceFrameIndices(Fn); |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 66 | |
| 67 | RegsToSave.clear(); |
| 68 | StackSlots.clear(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 69 | return true; |
| 70 | } |
| 71 | |
| 72 | private: |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 73 | std::vector<unsigned> RegsToSave; |
| 74 | std::vector<int> StackSlots; |
| 75 | |
| 76 | void calculateCallerSavedRegisters(MachineFunction &Fn); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 77 | void saveCallerSavedRegisters(MachineFunction &Fn); |
| 78 | void calculateFrameObjectOffsets(MachineFunction &Fn); |
| 79 | void replaceFrameIndices(MachineFunction &Fn); |
| 80 | void insertPrologEpilogCode(MachineFunction &Fn); |
| 81 | }; |
| 82 | } |
| 83 | |
Brian Gaeke | d0fde30 | 2003-11-11 22:41:34 +0000 | [diff] [blame] | 84 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 85 | /// createPrologEpilogCodeInserter - This function returns a pass that inserts |
| 86 | /// prolog and epilog code, and eliminates abstract frame references. |
| 87 | /// |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 88 | FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 89 | |
| 90 | |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 91 | /// calculateCallerSavedRegisters - Scan the function for modified caller saved |
| 92 | /// registers. Also calculate the MaxCallFrameSize and HasCalls variables for |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 93 | /// the function's frame information and eliminates call frame pseudo |
| 94 | /// instructions. |
| 95 | /// |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 96 | void PEI::calculateCallerSavedRegisters(MachineFunction &Fn) { |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 97 | const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 98 | const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 99 | |
| 100 | // Get the callee saved register list... |
| 101 | const unsigned *CSRegs = RegInfo->getCalleeSaveRegs(); |
| 102 | |
| 103 | // Get the function call frame set-up and tear-down instruction opcode |
| 104 | int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode(); |
| 105 | int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode(); |
| 106 | |
| 107 | // Early exit for targets which have no callee saved registers and no call |
| 108 | // frame setup/destroy pseudo instructions. |
| 109 | if ((CSRegs == 0 || CSRegs[0] == 0) && |
| 110 | FrameSetupOpcode == -1 && FrameDestroyOpcode == -1) |
| 111 | return; |
| 112 | |
| 113 | // This bitset contains an entry for each physical register for the target... |
Alkis Evlogimenos | 859a18b | 2004-02-15 21:37:17 +0000 | [diff] [blame] | 114 | std::vector<bool> ModifiedRegs(RegInfo->getNumRegs()); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 115 | unsigned MaxCallFrameSize = 0; |
| 116 | bool HasCalls = false; |
| 117 | |
| 118 | for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) |
| 119 | for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 120 | if (I->getOpcode() == FrameSetupOpcode || |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 121 | I->getOpcode() == FrameDestroyOpcode) { |
| 122 | assert(I->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo" |
| 123 | " instructions should have a single immediate argument!"); |
| 124 | unsigned Size = I->getOperand(0).getImmedValue(); |
| 125 | if (Size > MaxCallFrameSize) MaxCallFrameSize = Size; |
| 126 | HasCalls = true; |
| 127 | RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I++); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 128 | } else { |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 129 | for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { |
| 130 | MachineOperand &MO = I->getOperand(i); |
| 131 | if (MO.isRegister() && MO.isDef()) { |
Chris Lattner | 1cbe4d0 | 2004-02-10 21:12:22 +0000 | [diff] [blame] | 132 | assert(MRegisterInfo::isPhysicalRegister(MO.getReg()) && |
| 133 | "Register allocation must be performed!"); |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 134 | ModifiedRegs[MO.getReg()] = true; // Register is modified |
Chris Lattner | 1cbe4d0 | 2004-02-10 21:12:22 +0000 | [diff] [blame] | 135 | } |
| 136 | } |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 137 | ++I; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 138 | } |
| 139 | |
Chris Lattner | eb24db9 | 2002-12-28 21:08:26 +0000 | [diff] [blame] | 140 | MachineFrameInfo *FFI = Fn.getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 141 | FFI->setHasCalls(HasCalls); |
| 142 | FFI->setMaxCallFrameSize(MaxCallFrameSize); |
| 143 | |
| 144 | // Now figure out which *callee saved* registers are modified by the current |
| 145 | // function, thus needing to be saved and restored in the prolog/epilog. |
| 146 | // |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 147 | for (unsigned i = 0; CSRegs[i]; ++i) { |
| 148 | unsigned Reg = CSRegs[i]; |
| 149 | if (ModifiedRegs[Reg]) { |
| 150 | RegsToSave.push_back(Reg); // If modified register... |
Alkis Evlogimenos | 73ff512 | 2003-10-08 05:20:08 +0000 | [diff] [blame] | 151 | } else { |
| 152 | for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg); |
| 153 | *AliasSet; ++AliasSet) { // Check alias registers too... |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 154 | if (ModifiedRegs[*AliasSet]) { |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 155 | RegsToSave.push_back(Reg); |
| 156 | break; |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 157 | } |
Alkis Evlogimenos | 73ff512 | 2003-10-08 05:20:08 +0000 | [diff] [blame] | 158 | } |
| 159 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 160 | } |
| 161 | |
| 162 | if (RegsToSave.empty()) |
| 163 | return; // Early exit if no caller saved registers are modified! |
| 164 | |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 165 | unsigned NumFixedSpillSlots; |
Alkis Evlogimenos | 8c9b4de | 2004-08-15 09:18:55 +0000 | [diff] [blame] | 166 | const std::pair<unsigned,int> *FixedSpillSlots = |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 167 | TFI->getCalleeSaveSpillSlots(NumFixedSpillSlots); |
| 168 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 169 | // Now that we know which registers need to be saved and restored, allocate |
| 170 | // stack slots for them. |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 171 | for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 172 | unsigned Reg = RegsToSave[i]; |
| 173 | int FrameIdx; |
| 174 | const TargetRegisterClass *RC = RegInfo->getRegClass(Reg); |
| 175 | |
| 176 | // Check to see if this physreg must be spilled to a particular stack slot |
| 177 | // on this target. |
Alkis Evlogimenos | 8c9b4de | 2004-08-15 09:18:55 +0000 | [diff] [blame] | 178 | const std::pair<unsigned,int> *FixedSlot = FixedSpillSlots; |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 179 | while (FixedSlot != FixedSpillSlots+NumFixedSpillSlots && |
| 180 | FixedSlot->first != Reg) |
| 181 | ++FixedSlot; |
| 182 | |
| 183 | if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) { |
| 184 | // Nope, just spill it anywhere convenient. |
| 185 | FrameIdx = FFI->CreateStackObject(RC); |
| 186 | } else { |
| 187 | // Spill it to the stack where we must. |
| 188 | FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->second); |
| 189 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 190 | StackSlots.push_back(FrameIdx); |
| 191 | } |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 192 | } |
| 193 | |
| 194 | /// saveCallerSavedRegisters - Insert spill code for any caller saved registers |
| 195 | /// that are modified in the function. |
| 196 | /// |
| 197 | void PEI::saveCallerSavedRegisters(MachineFunction &Fn) { |
| 198 | // Early exit if no caller saved registers are modified! |
| 199 | if (RegsToSave.empty()) |
| 200 | return; |
| 201 | |
| 202 | const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 203 | |
| 204 | // Now that we have a stack slot for each register to be saved, insert spill |
| 205 | // code into the entry block... |
| 206 | MachineBasicBlock *MBB = Fn.begin(); |
| 207 | MachineBasicBlock::iterator I = MBB->begin(); |
| 208 | for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { |
Chris Lattner | 57f1b67 | 2004-08-15 21:56:44 +0000 | [diff] [blame^] | 209 | // Insert the spill to the stack frame. |
| 210 | RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i]); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 211 | } |
| 212 | |
| 213 | // Add code to restore the callee-save registers in each exiting block. |
Chris Lattner | 9bcdcd1 | 2004-06-02 05:57:12 +0000 | [diff] [blame] | 214 | const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 215 | for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI) { |
| 216 | // If last instruction is a return instruction, add an epilogue |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 217 | if (!FI->empty() && TII.isReturn(FI->back().getOpcode())) { |
| 218 | MBB = FI; |
| 219 | I = MBB->end(); --I; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 220 | |
| 221 | for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { |
Chris Lattner | 57f1b67 | 2004-08-15 21:56:44 +0000 | [diff] [blame^] | 222 | RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i],StackSlots[i]); |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 223 | --I; // Insert in reverse order |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 224 | } |
| 225 | } |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | |
| 230 | /// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the |
| 231 | /// abstract stack objects... |
| 232 | /// |
| 233 | void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { |
Chris Lattner | 9bcdcd1 | 2004-06-02 05:57:12 +0000 | [diff] [blame] | 234 | const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 235 | |
| 236 | bool StackGrowsDown = |
| 237 | TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 238 | |
| 239 | // Loop over all of the stack objects, assigning sequential addresses... |
Chris Lattner | eb24db9 | 2002-12-28 21:08:26 +0000 | [diff] [blame] | 240 | MachineFrameInfo *FFI = Fn.getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 241 | |
Chris Lattner | f85249c | 2003-01-16 02:24:20 +0000 | [diff] [blame] | 242 | unsigned StackAlignment = TFI.getStackAlignment(); |
Chris Lattner | 78d6db5 | 2003-01-16 02:22:08 +0000 | [diff] [blame] | 243 | |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 244 | // Start at the beginning of the local area. |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 245 | // The Offset is the distance from the stack top in the direction |
| 246 | // of stack growth -- so it's always positive. |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 247 | int Offset = TFI.getOffsetOfLocalArea(); |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 248 | if (StackGrowsDown) |
Chris Lattner | 7f7bbc2 | 2004-06-11 06:37:11 +0000 | [diff] [blame] | 249 | Offset = -Offset; |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 250 | assert(Offset >= 0 |
| 251 | && "Local area offset should be in direction of stack growth"); |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 252 | |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 253 | // If there are fixed sized objects that are preallocated in the local area, |
| 254 | // non-fixed objects can't be allocated right at the start of local area. |
| 255 | // We currently don't support filling in holes in between fixed sized objects, |
| 256 | // so we adjust 'Offset' to point to the end of last fixed sized |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 257 | // preallocated object. |
| 258 | for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) { |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 259 | int FixedOff; |
| 260 | if (StackGrowsDown) { |
| 261 | // The maximum distance from the stack pointer is at lower address of |
| 262 | // the object -- which is given by offset. For down growing stack |
| 263 | // the offset is negative, so we negate the offset to get the distance. |
| 264 | FixedOff = -FFI->getObjectOffset(i); |
| 265 | } else { |
| 266 | // The maximum distance from the start pointer is at the upper |
| 267 | // address of the object. |
| 268 | FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i); |
| 269 | } |
| 270 | if (FixedOff > Offset) Offset = FixedOff; |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 271 | } |
| 272 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 273 | for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) { |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 274 | // If stack grows down, we need to add size of find the lowest |
| 275 | // address of the object. |
| 276 | if (StackGrowsDown) |
| 277 | Offset += FFI->getObjectSize(i); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 278 | |
| 279 | unsigned Align = FFI->getObjectAlignment(i); |
Chris Lattner | f85249c | 2003-01-16 02:24:20 +0000 | [diff] [blame] | 280 | assert(Align <= StackAlignment && "Cannot align stack object to higher " |
Chris Lattner | 78d6db5 | 2003-01-16 02:22:08 +0000 | [diff] [blame] | 281 | "alignment boundary than the stack itself!"); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 282 | Offset = (Offset+Align-1)/Align*Align; // Adjust to Alignment boundary... |
| 283 | |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 284 | if (StackGrowsDown) { |
| 285 | FFI->setObjectOffset(i, -Offset); // Set the computed offset |
| 286 | } else { |
| 287 | FFI->setObjectOffset(i, Offset); |
| 288 | Offset += FFI->getObjectSize(i); |
| 289 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 290 | } |
| 291 | |
Chris Lattner | 9379929 | 2004-02-14 20:10:59 +0000 | [diff] [blame] | 292 | // Align the final stack pointer offset, but only if there are calls in the |
| 293 | // function. This ensures that any calls to subroutines have their stack |
| 294 | // frames suitable aligned. |
| 295 | if (FFI->hasCalls()) |
| 296 | Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 297 | |
| 298 | // Set the final value of the stack pointer... |
Chris Lattner | 7f7bbc2 | 2004-06-11 06:37:11 +0000 | [diff] [blame] | 299 | FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea()); |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 300 | } |
| 301 | |
| 302 | |
| 303 | /// insertPrologEpilogCode - Scan the function for modified caller saved |
| 304 | /// registers, insert spill code for these caller saved registers, then add |
| 305 | /// prolog and epilog code to the function. |
| 306 | /// |
| 307 | void PEI::insertPrologEpilogCode(MachineFunction &Fn) { |
| 308 | // Add prologue to the function... |
| 309 | Fn.getTarget().getRegisterInfo()->emitPrologue(Fn); |
| 310 | |
| 311 | // Add epilogue to restore the callee-save registers in each exiting block |
Chris Lattner | 9bcdcd1 | 2004-06-02 05:57:12 +0000 | [diff] [blame] | 312 | const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 313 | for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) { |
| 314 | // If last instruction is a return instruction, add an epilogue |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 315 | if (!I->empty() && TII.isReturn(I->back().getOpcode())) |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 316 | Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I); |
| 317 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 318 | } |
| 319 | |
| 320 | |
| 321 | /// replaceFrameIndices - Replace all MO_FrameIndex operands with physical |
| 322 | /// register references and actual offsets. |
| 323 | /// |
| 324 | void PEI::replaceFrameIndices(MachineFunction &Fn) { |
| 325 | if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do? |
| 326 | |
| 327 | const TargetMachine &TM = Fn.getTarget(); |
| 328 | assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!"); |
| 329 | const MRegisterInfo &MRI = *TM.getRegisterInfo(); |
| 330 | |
| 331 | for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) |
| 332 | for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 333 | for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 334 | if (I->getOperand(i).isFrameIndex()) { |
| 335 | // If this instruction has a FrameIndex operand, we need to use that |
| 336 | // target machine register info object to eliminate it. |
Nate Begeman | 5de0f7a | 2004-08-14 22:00:10 +0000 | [diff] [blame] | 337 | MRI.eliminateFrameIndex(I); |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 338 | break; |
| 339 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 340 | } |