1 //======-- MSP430FrameLowering.cpp - MSP430 Frame Information -------=========//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the MSP430 implementation of TargetFrameLowering class.
12 //===----------------------------------------------------------------------===//
14 #include "MSP430FrameLowering.h"
15 #include "MSP430InstrInfo.h"
16 #include "MSP430MachineFunctionInfo.h"
17 #include "llvm/Function.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/CodeGen/MachineFunction.h"
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
21 #include "llvm/CodeGen/MachineModuleInfo.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/Target/TargetData.h"
24 #include "llvm/Target/TargetOptions.h"
25 #include "llvm/Support/CommandLine.h"
29 bool MSP430FrameLowering::hasFP(const MachineFunction &MF) const {
30 const MachineFrameInfo *MFI = MF.getFrameInfo();
32 return (DisableFramePointerElim(MF) ||
33 MF.getFrameInfo()->hasVarSizedObjects() ||
34 MFI->isFrameAddressTaken());
37 bool MSP430FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
38 return !MF.getFrameInfo()->hasVarSizedObjects();
41 void MSP430FrameLowering::emitPrologue(MachineFunction &MF) const {
42 MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
43 MachineFrameInfo *MFI = MF.getFrameInfo();
44 MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
45 const MSP430InstrInfo &TII =
46 *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
48 MachineBasicBlock::iterator MBBI = MBB.begin();
49 DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
51 // Get the number of bytes to allocate from the FrameInfo.
52 uint64_t StackSize = MFI->getStackSize();
54 uint64_t NumBytes = 0;
56 // Calculate required stack adjustment
57 uint64_t FrameSize = StackSize - 2;
58 NumBytes = FrameSize - MSP430FI->getCalleeSavedFrameSize();
60 // Get the offset of the stack slot for the EBP register... which is
61 // guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
62 // Update the frame offset adjustment.
63 MFI->setOffsetAdjustment(-NumBytes);
65 // Save FPW into the appropriate stack slot...
66 BuildMI(MBB, MBBI, DL, TII.get(MSP430::PUSH16r))
67 .addReg(MSP430::FPW, RegState::Kill);
69 // Update FPW with the new base value...
70 BuildMI(MBB, MBBI, DL, TII.get(MSP430::MOV16rr), MSP430::FPW)
73 // Mark the FramePtr as live-in in every block except the entry.
74 for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
76 I->addLiveIn(MSP430::FPW);
79 NumBytes = StackSize - MSP430FI->getCalleeSavedFrameSize();
81 // Skip the callee-saved push instructions.
82 while (MBBI != MBB.end() && (MBBI->getOpcode() == MSP430::PUSH16r))
85 if (MBBI != MBB.end())
86 DL = MBBI->getDebugLoc();
88 if (NumBytes) { // adjust stack pointer: SPW -= numbytes
89 // If there is an SUB16ri of SPW immediately before this instruction, merge
91 //NumBytes -= mergeSPUpdates(MBB, MBBI, true);
92 // If there is an ADD16ri or SUB16ri of SPW immediately after this
93 // instruction, merge the two instructions.
94 // mergeSPUpdatesDown(MBB, MBBI, &NumBytes);
98 BuildMI(MBB, MBBI, DL, TII.get(MSP430::SUB16ri), MSP430::SPW)
99 .addReg(MSP430::SPW).addImm(NumBytes);
100 // The SRW implicit def is dead.
101 MI->getOperand(3).setIsDead();
106 void MSP430FrameLowering::emitEpilogue(MachineFunction &MF,
107 MachineBasicBlock &MBB) const {
108 const MachineFrameInfo *MFI = MF.getFrameInfo();
109 MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
110 const MSP430InstrInfo &TII =
111 *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
113 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
114 unsigned RetOpcode = MBBI->getOpcode();
115 DebugLoc DL = MBBI->getDebugLoc();
119 case MSP430::RETI: break; // These are ok
121 llvm_unreachable("Can only insert epilog into returning blocks");
124 // Get the number of bytes to allocate from the FrameInfo
125 uint64_t StackSize = MFI->getStackSize();
126 unsigned CSSize = MSP430FI->getCalleeSavedFrameSize();
127 uint64_t NumBytes = 0;
130 // Calculate required stack adjustment
131 uint64_t FrameSize = StackSize - 2;
132 NumBytes = FrameSize - CSSize;
135 BuildMI(MBB, MBBI, DL, TII.get(MSP430::POP16r), MSP430::FPW);
137 NumBytes = StackSize - CSSize;
139 // Skip the callee-saved pop instructions.
140 while (MBBI != MBB.begin()) {
141 MachineBasicBlock::iterator PI = prior(MBBI);
142 unsigned Opc = PI->getOpcode();
143 if (Opc != MSP430::POP16r && !PI->getDesc().isTerminator())
148 DL = MBBI->getDebugLoc();
150 // If there is an ADD16ri or SUB16ri of SPW immediately before this
151 // instruction, merge the two instructions.
152 //if (NumBytes || MFI->hasVarSizedObjects())
153 // mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
155 if (MFI->hasVarSizedObjects()) {
156 BuildMI(MBB, MBBI, DL,
157 TII.get(MSP430::MOV16rr), MSP430::SPW).addReg(MSP430::FPW);
160 BuildMI(MBB, MBBI, DL,
161 TII.get(MSP430::SUB16ri), MSP430::SPW)
162 .addReg(MSP430::SPW).addImm(CSSize);
163 // The SRW implicit def is dead.
164 MI->getOperand(3).setIsDead();
167 // adjust stack pointer back: SPW += numbytes
170 BuildMI(MBB, MBBI, DL, TII.get(MSP430::ADD16ri), MSP430::SPW)
171 .addReg(MSP430::SPW).addImm(NumBytes);
172 // The SRW implicit def is dead.
173 MI->getOperand(3).setIsDead();
178 // FIXME: Can we eleminate these in favour of generic code?
180 MSP430FrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
181 MachineBasicBlock::iterator MI,
182 const std::vector<CalleeSavedInfo> &CSI,
183 const TargetRegisterInfo *TRI) const {
188 if (MI != MBB.end()) DL = MI->getDebugLoc();
190 MachineFunction &MF = *MBB.getParent();
191 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
192 MSP430MachineFunctionInfo *MFI = MF.getInfo<MSP430MachineFunctionInfo>();
193 MFI->setCalleeSavedFrameSize(CSI.size() * 2);
195 for (unsigned i = CSI.size(); i != 0; --i) {
196 unsigned Reg = CSI[i-1].getReg();
197 // Add the callee-saved register as live-in. It's killed at the spill.
199 BuildMI(MBB, MI, DL, TII.get(MSP430::PUSH16r))
200 .addReg(Reg, RegState::Kill);
206 MSP430FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
207 MachineBasicBlock::iterator MI,
208 const std::vector<CalleeSavedInfo> &CSI,
209 const TargetRegisterInfo *TRI) const {
214 if (MI != MBB.end()) DL = MI->getDebugLoc();
216 MachineFunction &MF = *MBB.getParent();
217 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
219 for (unsigned i = 0, e = CSI.size(); i != e; ++i)
220 BuildMI(MBB, MI, DL, TII.get(MSP430::POP16r), CSI[i].getReg());