1 //===- MSP430RegisterInfo.cpp - MSP430 Register Information ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the MSP430 implementation of the TargetRegisterInfo class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #define DEBUG_TYPE "msp430-reg-info"
15
16 #include "MSP430.h"
17 #include "MSP430MachineFunctionInfo.h"
18 #include "MSP430RegisterInfo.h"
19 #include "MSP430TargetMachine.h"
20 #include "llvm/Function.h"
21 #include "llvm/CodeGen/MachineFrameInfo.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineInstrBuilder.h"
24 #include "llvm/Target/TargetMachine.h"
25 #include "llvm/Target/TargetOptions.h"
26 #include "llvm/ADT/BitVector.h"
27 #include "llvm/Support/ErrorHandling.h"
28
29 #define GET_REGINFO_TARGET_DESC
30 #include "MSP430GenRegisterInfo.inc"
31
32 using namespace llvm;
33
34 // FIXME: Provide proper call frame setup / destroy opcodes.
MSP430RegisterInfo(MSP430TargetMachine & tm,const TargetInstrInfo & tii)35 MSP430RegisterInfo::MSP430RegisterInfo(MSP430TargetMachine &tm,
36 const TargetInstrInfo &tii)
37 : MSP430GenRegisterInfo(MSP430::PCW), TM(tm), TII(tii) {
38 StackAlign = TM.getFrameLowering()->getStackAlignment();
39 }
40
41 const unsigned*
getCalleeSavedRegs(const MachineFunction * MF) const42 MSP430RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
43 const TargetFrameLowering *TFI = MF->getTarget().getFrameLowering();
44 const Function* F = MF->getFunction();
45 static const unsigned CalleeSavedRegs[] = {
46 MSP430::FPW, MSP430::R5W, MSP430::R6W, MSP430::R7W,
47 MSP430::R8W, MSP430::R9W, MSP430::R10W, MSP430::R11W,
48 0
49 };
50 static const unsigned CalleeSavedRegsFP[] = {
51 MSP430::R5W, MSP430::R6W, MSP430::R7W,
52 MSP430::R8W, MSP430::R9W, MSP430::R10W, MSP430::R11W,
53 0
54 };
55 static const unsigned CalleeSavedRegsIntr[] = {
56 MSP430::FPW, MSP430::R5W, MSP430::R6W, MSP430::R7W,
57 MSP430::R8W, MSP430::R9W, MSP430::R10W, MSP430::R11W,
58 MSP430::R12W, MSP430::R13W, MSP430::R14W, MSP430::R15W,
59 0
60 };
61 static const unsigned CalleeSavedRegsIntrFP[] = {
62 MSP430::R5W, MSP430::R6W, MSP430::R7W,
63 MSP430::R8W, MSP430::R9W, MSP430::R10W, MSP430::R11W,
64 MSP430::R12W, MSP430::R13W, MSP430::R14W, MSP430::R15W,
65 0
66 };
67
68 if (TFI->hasFP(*MF))
69 return (F->getCallingConv() == CallingConv::MSP430_INTR ?
70 CalleeSavedRegsIntrFP : CalleeSavedRegsFP);
71 else
72 return (F->getCallingConv() == CallingConv::MSP430_INTR ?
73 CalleeSavedRegsIntr : CalleeSavedRegs);
74
75 }
76
getReservedRegs(const MachineFunction & MF) const77 BitVector MSP430RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
78 BitVector Reserved(getNumRegs());
79 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
80
81 // Mark 4 special registers with subregisters as reserved.
82 Reserved.set(MSP430::PCB);
83 Reserved.set(MSP430::SPB);
84 Reserved.set(MSP430::SRB);
85 Reserved.set(MSP430::CGB);
86 Reserved.set(MSP430::PCW);
87 Reserved.set(MSP430::SPW);
88 Reserved.set(MSP430::SRW);
89 Reserved.set(MSP430::CGW);
90
91 // Mark frame pointer as reserved if needed.
92 if (TFI->hasFP(MF))
93 Reserved.set(MSP430::FPW);
94
95 return Reserved;
96 }
97
98 const TargetRegisterClass *
getPointerRegClass(unsigned Kind) const99 MSP430RegisterInfo::getPointerRegClass(unsigned Kind) const {
100 return &MSP430::GR16RegClass;
101 }
102
103 void MSP430RegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction & MF,MachineBasicBlock & MBB,MachineBasicBlock::iterator I) const104 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
105 MachineBasicBlock::iterator I) const {
106 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
107
108 if (!TFI->hasReservedCallFrame(MF)) {
109 // If the stack pointer can be changed after prologue, turn the
110 // adjcallstackup instruction into a 'sub SPW, <amt>' and the
111 // adjcallstackdown instruction into 'add SPW, <amt>'
112 // TODO: consider using push / pop instead of sub + store / add
113 MachineInstr *Old = I;
114 uint64_t Amount = Old->getOperand(0).getImm();
115 if (Amount != 0) {
116 // We need to keep the stack aligned properly. To do this, we round the
117 // amount of space needed for the outgoing arguments up to the next
118 // alignment boundary.
119 Amount = (Amount+StackAlign-1)/StackAlign*StackAlign;
120
121 MachineInstr *New = 0;
122 if (Old->getOpcode() == TII.getCallFrameSetupOpcode()) {
123 New = BuildMI(MF, Old->getDebugLoc(),
124 TII.get(MSP430::SUB16ri), MSP430::SPW)
125 .addReg(MSP430::SPW).addImm(Amount);
126 } else {
127 assert(Old->getOpcode() == TII.getCallFrameDestroyOpcode());
128 // factor out the amount the callee already popped.
129 uint64_t CalleeAmt = Old->getOperand(1).getImm();
130 Amount -= CalleeAmt;
131 if (Amount)
132 New = BuildMI(MF, Old->getDebugLoc(),
133 TII.get(MSP430::ADD16ri), MSP430::SPW)
134 .addReg(MSP430::SPW).addImm(Amount);
135 }
136
137 if (New) {
138 // The SRW implicit def is dead.
139 New->getOperand(3).setIsDead();
140
141 // Replace the pseudo instruction with a new instruction...
142 MBB.insert(I, New);
143 }
144 }
145 } else if (I->getOpcode() == TII.getCallFrameDestroyOpcode()) {
146 // If we are performing frame pointer elimination and if the callee pops
147 // something off the stack pointer, add it back.
148 if (uint64_t CalleeAmt = I->getOperand(1).getImm()) {
149 MachineInstr *Old = I;
150 MachineInstr *New =
151 BuildMI(MF, Old->getDebugLoc(), TII.get(MSP430::SUB16ri),
152 MSP430::SPW).addReg(MSP430::SPW).addImm(CalleeAmt);
153 // The SRW implicit def is dead.
154 New->getOperand(3).setIsDead();
155
156 MBB.insert(I, New);
157 }
158 }
159
160 MBB.erase(I);
161 }
162
163 void
eliminateFrameIndex(MachineBasicBlock::iterator II,int SPAdj,RegScavenger * RS) const164 MSP430RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
165 int SPAdj, RegScavenger *RS) const {
166 assert(SPAdj == 0 && "Unexpected");
167
168 unsigned i = 0;
169 MachineInstr &MI = *II;
170 MachineBasicBlock &MBB = *MI.getParent();
171 MachineFunction &MF = *MBB.getParent();
172 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
173 DebugLoc dl = MI.getDebugLoc();
174 while (!MI.getOperand(i).isFI()) {
175 ++i;
176 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
177 }
178
179 int FrameIndex = MI.getOperand(i).getIndex();
180
181 unsigned BasePtr = (TFI->hasFP(MF) ? MSP430::FPW : MSP430::SPW);
182 int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
183
184 // Skip the saved PC
185 Offset += 2;
186
187 if (!TFI->hasFP(MF))
188 Offset += MF.getFrameInfo()->getStackSize();
189 else
190 Offset += 2; // Skip the saved FPW
191
192 // Fold imm into offset
193 Offset += MI.getOperand(i+1).getImm();
194
195 if (MI.getOpcode() == MSP430::ADD16ri) {
196 // This is actually "load effective address" of the stack slot
197 // instruction. We have only two-address instructions, thus we need to
198 // expand it into mov + add
199
200 MI.setDesc(TII.get(MSP430::MOV16rr));
201 MI.getOperand(i).ChangeToRegister(BasePtr, false);
202
203 if (Offset == 0)
204 return;
205
206 // We need to materialize the offset via add instruction.
207 unsigned DstReg = MI.getOperand(0).getReg();
208 if (Offset < 0)
209 BuildMI(MBB, llvm::next(II), dl, TII.get(MSP430::SUB16ri), DstReg)
210 .addReg(DstReg).addImm(-Offset);
211 else
212 BuildMI(MBB, llvm::next(II), dl, TII.get(MSP430::ADD16ri), DstReg)
213 .addReg(DstReg).addImm(Offset);
214
215 return;
216 }
217
218 MI.getOperand(i).ChangeToRegister(BasePtr, false);
219 MI.getOperand(i+1).ChangeToImmediate(Offset);
220 }
221
222 void
processFunctionBeforeFrameFinalized(MachineFunction & MF) const223 MSP430RegisterInfo::processFunctionBeforeFrameFinalized(MachineFunction &MF)
224 const {
225 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
226
227 // Create a frame entry for the FPW register that must be saved.
228 if (TFI->hasFP(MF)) {
229 int FrameIdx = MF.getFrameInfo()->CreateFixedObject(2, -4, true);
230 (void)FrameIdx;
231 assert(FrameIdx == MF.getFrameInfo()->getObjectIndexBegin() &&
232 "Slot for FPW register must be last in order to be found!");
233 }
234 }
235
getFrameRegister(const MachineFunction & MF) const236 unsigned MSP430RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
237 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
238
239 return TFI->hasFP(MF) ? MSP430::FPW : MSP430::SPW;
240 }
241