Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 1 | //===-- PrologEpilogInserter.cpp - Insert Prolog/Epilog code in function --===// |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 2 | // |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 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. |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 7 | // |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 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 | f8c68f6 | 2006-06-28 22:17:39 +0000 | [diff] [blame^] | 27 | #include "llvm/Support/Visibility.h" |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 28 | using namespace llvm; |
Brian Gaeke | d0fde30 | 2003-11-11 22:41:34 +0000 | [diff] [blame] | 29 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 30 | namespace { |
Chris Lattner | f8c68f6 | 2006-06-28 22:17:39 +0000 | [diff] [blame^] | 31 | struct VISIBILITY_HIDDEN PEI : public MachineFunctionPass { |
Chris Lattner | f00a3f9 | 2003-01-13 00:23:41 +0000 | [diff] [blame] | 32 | const char *getPassName() const { |
| 33 | return "Prolog/Epilog Insertion & Frame Finalization"; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 34 | } |
| 35 | |
| 36 | /// runOnMachineFunction - Insert prolog/epilog code and replace abstract |
| 37 | /// frame indexes with appropriate references. |
| 38 | /// |
| 39 | bool runOnMachineFunction(MachineFunction &Fn) { |
Jim Laskey | 4188699 | 2006-04-07 16:34:46 +0000 | [diff] [blame] | 40 | // Get MachineDebugInfo so that we can track the construction of the |
| 41 | // frame. |
| 42 | if (MachineDebugInfo *DI = getAnalysisToUpdate<MachineDebugInfo>()) { |
| 43 | Fn.getFrameInfo()->setMachineDebugInfo(DI); |
| 44 | } |
| 45 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 46 | // Scan the function for modified caller saved registers and insert spill |
| 47 | // code for any caller saved registers that are modified. Also calculate |
| 48 | // the MaxCallFrameSize and HasCalls variables for the function's frame |
| 49 | // information and eliminates call frame pseudo instructions. |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 50 | calculateCallerSavedRegisters(Fn); |
| 51 | |
| 52 | // Add the code to save and restore the caller saved registers |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 53 | saveCallerSavedRegisters(Fn); |
| 54 | |
| 55 | // Allow the target machine to make final modifications to the function |
| 56 | // before the frame layout is finalized. |
| 57 | Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn); |
| 58 | |
| 59 | // Calculate actual frame offsets for all of the abstract stack objects... |
| 60 | calculateFrameObjectOffsets(Fn); |
| 61 | |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 62 | // Add prolog and epilog code to the function. This function is required |
| 63 | // to align the stack frame as necessary for any stack variables or |
| 64 | // called functions. Because of this, calculateCallerSavedRegisters |
| 65 | // must be called before this function in order to set the HasCalls |
| 66 | // and MaxCallFrameSize variables. |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 67 | insertPrologEpilogCode(Fn); |
| 68 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 69 | // Replace all MO_FrameIndex operands with physical register references |
| 70 | // and actual offsets. |
| 71 | // |
| 72 | replaceFrameIndices(Fn); |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 73 | |
| 74 | RegsToSave.clear(); |
| 75 | StackSlots.clear(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 76 | return true; |
| 77 | } |
| 78 | |
| 79 | private: |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 80 | std::vector<std::pair<unsigned, const TargetRegisterClass*> > RegsToSave; |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 81 | std::vector<int> StackSlots; |
| 82 | |
| 83 | void calculateCallerSavedRegisters(MachineFunction &Fn); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 84 | void saveCallerSavedRegisters(MachineFunction &Fn); |
| 85 | void calculateFrameObjectOffsets(MachineFunction &Fn); |
| 86 | void replaceFrameIndices(MachineFunction &Fn); |
| 87 | void insertPrologEpilogCode(MachineFunction &Fn); |
| 88 | }; |
| 89 | } |
| 90 | |
Brian Gaeke | d0fde30 | 2003-11-11 22:41:34 +0000 | [diff] [blame] | 91 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 92 | /// createPrologEpilogCodeInserter - This function returns a pass that inserts |
| 93 | /// prolog and epilog code, and eliminates abstract frame references. |
| 94 | /// |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 95 | FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 96 | |
| 97 | |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 98 | /// calculateCallerSavedRegisters - Scan the function for modified caller saved |
| 99 | /// registers. Also calculate the MaxCallFrameSize and HasCalls variables for |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 100 | /// the function's frame information and eliminates call frame pseudo |
| 101 | /// instructions. |
| 102 | /// |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 103 | void PEI::calculateCallerSavedRegisters(MachineFunction &Fn) { |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 104 | const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 105 | const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 106 | |
| 107 | // Get the callee saved register list... |
| 108 | const unsigned *CSRegs = RegInfo->getCalleeSaveRegs(); |
| 109 | |
| 110 | // Get the function call frame set-up and tear-down instruction opcode |
| 111 | int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode(); |
| 112 | int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode(); |
| 113 | |
| 114 | // Early exit for targets which have no callee saved registers and no call |
| 115 | // frame setup/destroy pseudo instructions. |
| 116 | if ((CSRegs == 0 || CSRegs[0] == 0) && |
| 117 | FrameSetupOpcode == -1 && FrameDestroyOpcode == -1) |
| 118 | return; |
| 119 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 120 | unsigned MaxCallFrameSize = 0; |
| 121 | bool HasCalls = false; |
| 122 | |
| 123 | for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) |
| 124 | for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 125 | if (I->getOpcode() == FrameSetupOpcode || |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 126 | I->getOpcode() == FrameDestroyOpcode) { |
Chris Lattner | 2a82ef3 | 2005-05-13 21:07:15 +0000 | [diff] [blame] | 127 | assert(I->getNumOperands() >= 1 && "Call Frame Setup/Destroy Pseudo" |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 128 | " instructions should have a single immediate argument!"); |
| 129 | unsigned Size = I->getOperand(0).getImmedValue(); |
| 130 | if (Size > MaxCallFrameSize) MaxCallFrameSize = Size; |
| 131 | HasCalls = true; |
| 132 | RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I++); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 133 | } else { |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 134 | ++I; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 135 | } |
| 136 | |
Chris Lattner | eb24db9 | 2002-12-28 21:08:26 +0000 | [diff] [blame] | 137 | MachineFrameInfo *FFI = Fn.getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 138 | FFI->setHasCalls(HasCalls); |
| 139 | FFI->setMaxCallFrameSize(MaxCallFrameSize); |
| 140 | |
| 141 | // Now figure out which *callee saved* registers are modified by the current |
| 142 | // function, thus needing to be saved and restored in the prolog/epilog. |
| 143 | // |
Chris Lattner | 3563015 | 2005-01-23 23:13:12 +0000 | [diff] [blame] | 144 | const bool *PhysRegsUsed = Fn.getUsedPhysregs(); |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 145 | const TargetRegisterClass* const *CSRegClasses = |
| 146 | RegInfo->getCalleeSaveRegClasses(); |
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]; |
Chris Lattner | 3563015 | 2005-01-23 23:13:12 +0000 | [diff] [blame] | 149 | if (PhysRegsUsed[Reg]) { |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 150 | // If the reg is modified, save it! |
| 151 | RegsToSave.push_back(std::make_pair(Reg, CSRegClasses[i])); |
Alkis Evlogimenos | 73ff512 | 2003-10-08 05:20:08 +0000 | [diff] [blame] | 152 | } else { |
| 153 | for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg); |
Chris Lattner | 3563015 | 2005-01-23 23:13:12 +0000 | [diff] [blame] | 154 | *AliasSet; ++AliasSet) { // Check alias registers too. |
| 155 | if (PhysRegsUsed[*AliasSet]) { |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 156 | RegsToSave.push_back(std::make_pair(Reg, CSRegClasses[i])); |
Chris Lattner | d555da5 | 2004-08-07 07:07:57 +0000 | [diff] [blame] | 157 | break; |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 158 | } |
Alkis Evlogimenos | 73ff512 | 2003-10-08 05:20:08 +0000 | [diff] [blame] | 159 | } |
| 160 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 161 | } |
| 162 | |
| 163 | if (RegsToSave.empty()) |
| 164 | return; // Early exit if no caller saved registers are modified! |
| 165 | |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 166 | unsigned NumFixedSpillSlots; |
Alkis Evlogimenos | 8c9b4de | 2004-08-15 09:18:55 +0000 | [diff] [blame] | 167 | const std::pair<unsigned,int> *FixedSpillSlots = |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 168 | TFI->getCalleeSaveSpillSlots(NumFixedSpillSlots); |
| 169 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 170 | // Now that we know which registers need to be saved and restored, allocate |
| 171 | // stack slots for them. |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 172 | for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 173 | unsigned Reg = RegsToSave[i].first; |
Chris Lattner | 8fb040e | 2005-09-30 17:19:22 +0000 | [diff] [blame] | 174 | const TargetRegisterClass *RC = RegsToSave[i].second; |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 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 | |
Chris Lattner | fa1face | 2004-08-21 19:45:10 +0000 | [diff] [blame] | 183 | int FrameIdx; |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 184 | if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) { |
| 185 | // Nope, just spill it anywhere convenient. |
Chris Lattner | 8fb040e | 2005-09-30 17:19:22 +0000 | [diff] [blame] | 186 | FrameIdx = FFI->CreateStackObject(RC->getSize(), RC->getAlignment()); |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 187 | } else { |
| 188 | // Spill it to the stack where we must. |
Chris Lattner | 8fb040e | 2005-09-30 17:19:22 +0000 | [diff] [blame] | 189 | FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->second); |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 190 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 191 | StackSlots.push_back(FrameIdx); |
| 192 | } |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 193 | } |
| 194 | |
| 195 | /// saveCallerSavedRegisters - Insert spill code for any caller saved registers |
| 196 | /// that are modified in the function. |
| 197 | /// |
| 198 | void PEI::saveCallerSavedRegisters(MachineFunction &Fn) { |
| 199 | // Early exit if no caller saved registers are modified! |
| 200 | if (RegsToSave.empty()) |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 201 | return; |
Chris Lattner | c330b68 | 2004-08-12 19:01:14 +0000 | [diff] [blame] | 202 | |
| 203 | const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 204 | |
| 205 | // Now that we have a stack slot for each register to be saved, insert spill |
Chris Lattner | 92b9fce | 2005-01-23 21:45:01 +0000 | [diff] [blame] | 206 | // code into the entry block. |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 207 | MachineBasicBlock *MBB = Fn.begin(); |
| 208 | MachineBasicBlock::iterator I = MBB->begin(); |
| 209 | for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { |
Chris Lattner | 57f1b67 | 2004-08-15 21:56:44 +0000 | [diff] [blame] | 210 | // Insert the spill to the stack frame. |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 211 | RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i].first, StackSlots[i], |
| 212 | RegsToSave[i].second); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 213 | } |
| 214 | |
| 215 | // Add code to restore the callee-save registers in each exiting block. |
Chris Lattner | 9bcdcd1 | 2004-06-02 05:57:12 +0000 | [diff] [blame] | 216 | const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); |
Chris Lattner | 92b9fce | 2005-01-23 21:45:01 +0000 | [diff] [blame] | 217 | for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI) |
| 218 | // If last instruction is a return instruction, add an epilogue. |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 219 | if (!FI->empty() && TII.isReturn(FI->back().getOpcode())) { |
| 220 | MBB = FI; |
| 221 | I = MBB->end(); --I; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 222 | |
Chris Lattner | 4fc9979 | 2005-05-15 03:09:58 +0000 | [diff] [blame] | 223 | // Skip over all terminator instructions, which are part of the return |
| 224 | // sequence. |
| 225 | MachineBasicBlock::iterator I2 = I; |
| 226 | while (I2 != MBB->begin() && TII.isTerminatorInstr((--I2)->getOpcode())) |
| 227 | I = I2; |
| 228 | |
Chris Lattner | dfd5870 | 2005-08-29 00:10:46 +0000 | [diff] [blame] | 229 | bool AtStart = I == MBB->begin(); |
Chris Lattner | ed461e0 | 2005-08-26 22:18:32 +0000 | [diff] [blame] | 230 | MachineBasicBlock::iterator BeforeI = I; |
| 231 | if (!AtStart) |
| 232 | --BeforeI; |
| 233 | |
Chris Lattner | 4fc9979 | 2005-05-15 03:09:58 +0000 | [diff] [blame] | 234 | // Restore all registers immediately before the return and any terminators |
| 235 | // that preceed it. |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 236 | for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) { |
Chris Lattner | 80a4f16 | 2005-09-30 16:59:07 +0000 | [diff] [blame] | 237 | RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i].first, |
| 238 | StackSlots[i], RegsToSave[i].second); |
Chris Lattner | 3ca6a2c | 2005-01-19 21:32:07 +0000 | [diff] [blame] | 239 | assert(I != MBB->begin() && |
| 240 | "loadRegFromStackSlot didn't insert any code!"); |
Chris Lattner | ed461e0 | 2005-08-26 22:18:32 +0000 | [diff] [blame] | 241 | // Insert in reverse order. loadRegFromStackSlot can insert multiple |
| 242 | // instructions. |
| 243 | if (AtStart) |
| 244 | I = MBB->begin(); |
| 245 | else { |
| 246 | I = BeforeI; |
| 247 | ++I; |
| 248 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 249 | } |
| 250 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 251 | } |
| 252 | |
| 253 | |
| 254 | /// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the |
Chris Lattner | 92b9fce | 2005-01-23 21:45:01 +0000 | [diff] [blame] | 255 | /// abstract stack objects. |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 256 | /// |
| 257 | void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { |
Chris Lattner | 9bcdcd1 | 2004-06-02 05:57:12 +0000 | [diff] [blame] | 258 | const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo(); |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 259 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 260 | bool StackGrowsDown = |
| 261 | TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown; |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 262 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 263 | // Loop over all of the stack objects, assigning sequential addresses... |
Chris Lattner | eb24db9 | 2002-12-28 21:08:26 +0000 | [diff] [blame] | 264 | MachineFrameInfo *FFI = Fn.getFrameInfo(); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 265 | |
Chris Lattner | f85249c | 2003-01-16 02:24:20 +0000 | [diff] [blame] | 266 | unsigned StackAlignment = TFI.getStackAlignment(); |
Chris Lattner | cbef8ba | 2005-11-06 17:43:20 +0000 | [diff] [blame] | 267 | unsigned MaxAlign = 0; |
Chris Lattner | 78d6db5 | 2003-01-16 02:22:08 +0000 | [diff] [blame] | 268 | |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 269 | // Start at the beginning of the local area. |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 270 | // The Offset is the distance from the stack top in the direction |
| 271 | // of stack growth -- so it's always positive. |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 272 | int Offset = TFI.getOffsetOfLocalArea(); |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 273 | if (StackGrowsDown) |
Chris Lattner | 7f7bbc2 | 2004-06-11 06:37:11 +0000 | [diff] [blame] | 274 | Offset = -Offset; |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 275 | assert(Offset >= 0 |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 276 | && "Local area offset should be in direction of stack growth"); |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 277 | |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 278 | // If there are fixed sized objects that are preallocated in the local area, |
| 279 | // non-fixed objects can't be allocated right at the start of local area. |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 280 | // We currently don't support filling in holes in between fixed sized objects, |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 281 | // 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] | 282 | // preallocated object. |
| 283 | for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) { |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 284 | int FixedOff; |
| 285 | if (StackGrowsDown) { |
| 286 | // The maximum distance from the stack pointer is at lower address of |
| 287 | // the object -- which is given by offset. For down growing stack |
| 288 | // the offset is negative, so we negate the offset to get the distance. |
| 289 | FixedOff = -FFI->getObjectOffset(i); |
| 290 | } else { |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 291 | // The maximum distance from the start pointer is at the upper |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 292 | // address of the object. |
| 293 | FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i); |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 294 | } |
| 295 | if (FixedOff > Offset) Offset = FixedOff; |
Chris Lattner | 05d8350 | 2004-02-15 00:14:20 +0000 | [diff] [blame] | 296 | } |
| 297 | |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 298 | for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) { |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 299 | // If stack grows down, we need to add size of find the lowest |
| 300 | // address of the object. |
| 301 | if (StackGrowsDown) |
| 302 | Offset += FFI->getObjectSize(i); |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 303 | |
| 304 | unsigned Align = FFI->getObjectAlignment(i); |
Nate Begeman | ae232e7 | 2005-11-06 09:00:38 +0000 | [diff] [blame] | 305 | // If the alignment of this object is greater than that of the stack, then |
| 306 | // increase the stack alignment to match. |
| 307 | MaxAlign = std::max(MaxAlign, Align); |
| 308 | // Adjust to alignment boundary |
| 309 | Offset = (Offset+Align-1)/Align*Align; |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 310 | |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 311 | if (StackGrowsDown) { |
| 312 | FFI->setObjectOffset(i, -Offset); // Set the computed offset |
| 313 | } else { |
Misha Brukman | edf128a | 2005-04-21 22:36:52 +0000 | [diff] [blame] | 314 | FFI->setObjectOffset(i, Offset); |
Chris Lattner | 577aec1 | 2004-06-10 06:23:35 +0000 | [diff] [blame] | 315 | Offset += FFI->getObjectSize(i); |
| 316 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 317 | } |
| 318 | |
Chris Lattner | 9379929 | 2004-02-14 20:10:59 +0000 | [diff] [blame] | 319 | // Align the final stack pointer offset, but only if there are calls in the |
| 320 | // function. This ensures that any calls to subroutines have their stack |
| 321 | // frames suitable aligned. |
| 322 | if (FFI->hasCalls()) |
| 323 | Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment; |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 324 | |
| 325 | // Set the final value of the stack pointer... |
Chris Lattner | 7f7bbc2 | 2004-06-11 06:37:11 +0000 | [diff] [blame] | 326 | FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea()); |
Chris Lattner | cbef8ba | 2005-11-06 17:43:20 +0000 | [diff] [blame] | 327 | |
| 328 | // Remember the required stack alignment in case targets need it to perform |
| 329 | // dynamic stack alignment. |
Chris Lattner | 4672f71 | 2006-04-03 21:39:57 +0000 | [diff] [blame] | 330 | assert(FFI->getMaxAlignment() == MaxAlign && |
| 331 | "Stack alignment calculation broken!"); |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 332 | } |
| 333 | |
| 334 | |
| 335 | /// insertPrologEpilogCode - Scan the function for modified caller saved |
| 336 | /// registers, insert spill code for these caller saved registers, then add |
| 337 | /// prolog and epilog code to the function. |
| 338 | /// |
| 339 | void PEI::insertPrologEpilogCode(MachineFunction &Fn) { |
| 340 | // Add prologue to the function... |
| 341 | Fn.getTarget().getRegisterInfo()->emitPrologue(Fn); |
| 342 | |
| 343 | // Add epilogue to restore the callee-save registers in each exiting block |
Chris Lattner | 9bcdcd1 | 2004-06-02 05:57:12 +0000 | [diff] [blame] | 344 | const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo(); |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 345 | for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) { |
| 346 | // If last instruction is a return instruction, add an epilogue |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 347 | if (!I->empty() && TII.isReturn(I->back().getOpcode())) |
Chris Lattner | 4ac7d73 | 2003-01-15 22:52:34 +0000 | [diff] [blame] | 348 | Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I); |
| 349 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 350 | } |
| 351 | |
| 352 | |
| 353 | /// replaceFrameIndices - Replace all MO_FrameIndex operands with physical |
| 354 | /// register references and actual offsets. |
| 355 | /// |
| 356 | void PEI::replaceFrameIndices(MachineFunction &Fn) { |
| 357 | if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do? |
| 358 | |
| 359 | const TargetMachine &TM = Fn.getTarget(); |
| 360 | assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!"); |
| 361 | const MRegisterInfo &MRI = *TM.getRegisterInfo(); |
| 362 | |
| 363 | for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) |
| 364 | for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) |
Alkis Evlogimenos | c0b9dc5 | 2004-02-12 02:27:10 +0000 | [diff] [blame] | 365 | for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 366 | if (I->getOperand(i).isFrameIndex()) { |
| 367 | // If this instruction has a FrameIndex operand, we need to use that |
| 368 | // target machine register info object to eliminate it. |
Nate Begeman | 5de0f7a | 2004-08-14 22:00:10 +0000 | [diff] [blame] | 369 | MRI.eliminateFrameIndex(I); |
Chris Lattner | ecf8afd | 2004-08-07 07:18:41 +0000 | [diff] [blame] | 370 | break; |
| 371 | } |
Chris Lattner | 58b3328 | 2002-12-28 20:43:30 +0000 | [diff] [blame] | 372 | } |