1 //===-- MSP430RegisterInfo.cpp - MSP430 Register Information --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains the MSP430 implementation of the TargetRegisterInfo class.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "MSP430RegisterInfo.h"
14 #include "MSP430.h"
15 #include "MSP430MachineFunctionInfo.h"
16 #include "MSP430TargetMachine.h"
17 #include "llvm/ADT/BitVector.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/CodeGen/MachineFunction.h"
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
21 #include "llvm/IR/Function.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Target/TargetMachine.h"
24 #include "llvm/Target/TargetOptions.h"
25
26 using namespace llvm;
27
28 #define DEBUG_TYPE "msp430-reg-info"
29
30 #define GET_REGINFO_TARGET_DESC
31 #include "MSP430GenRegisterInfo.inc"
32
33 // FIXME: Provide proper call frame setup / destroy opcodes.
MSP430RegisterInfo()34 MSP430RegisterInfo::MSP430RegisterInfo()
35 : MSP430GenRegisterInfo(MSP430::PC) {}
36
37 const MCPhysReg*
getCalleeSavedRegs(const MachineFunction * MF) const38 MSP430RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
39 const MSP430FrameLowering *TFI = getFrameLowering(*MF);
40 const Function* F = &MF->getFunction();
41 static const MCPhysReg CalleeSavedRegs[] = {
42 MSP430::R4, MSP430::R5, MSP430::R6, MSP430::R7,
43 MSP430::R8, MSP430::R9, MSP430::R10,
44 0
45 };
46 static const MCPhysReg CalleeSavedRegsFP[] = {
47 MSP430::R5, MSP430::R6, MSP430::R7,
48 MSP430::R8, MSP430::R9, MSP430::R10,
49 0
50 };
51 static const MCPhysReg CalleeSavedRegsIntr[] = {
52 MSP430::R4, MSP430::R5, MSP430::R6, MSP430::R7,
53 MSP430::R8, MSP430::R9, MSP430::R10, MSP430::R11,
54 MSP430::R12, MSP430::R13, MSP430::R14, MSP430::R15,
55 0
56 };
57 static const MCPhysReg CalleeSavedRegsIntrFP[] = {
58 MSP430::R5, MSP430::R6, MSP430::R7,
59 MSP430::R8, MSP430::R9, MSP430::R10, MSP430::R11,
60 MSP430::R12, MSP430::R13, MSP430::R14, MSP430::R15,
61 0
62 };
63
64 if (TFI->hasFP(*MF))
65 return (F->getCallingConv() == CallingConv::MSP430_INTR ?
66 CalleeSavedRegsIntrFP : CalleeSavedRegsFP);
67 else
68 return (F->getCallingConv() == CallingConv::MSP430_INTR ?
69 CalleeSavedRegsIntr : CalleeSavedRegs);
70
71 }
72
getReservedRegs(const MachineFunction & MF) const73 BitVector MSP430RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
74 BitVector Reserved(getNumRegs());
75 const MSP430FrameLowering *TFI = getFrameLowering(MF);
76
77 // Mark 4 special registers with subregisters as reserved.
78 Reserved.set(MSP430::PCB);
79 Reserved.set(MSP430::SPB);
80 Reserved.set(MSP430::SRB);
81 Reserved.set(MSP430::CGB);
82 Reserved.set(MSP430::PC);
83 Reserved.set(MSP430::SP);
84 Reserved.set(MSP430::SR);
85 Reserved.set(MSP430::CG);
86
87 // Mark frame pointer as reserved if needed.
88 if (TFI->hasFP(MF)) {
89 Reserved.set(MSP430::R4B);
90 Reserved.set(MSP430::R4);
91 }
92
93 return Reserved;
94 }
95
96 const TargetRegisterClass *
getPointerRegClass(const MachineFunction & MF,unsigned Kind) const97 MSP430RegisterInfo::getPointerRegClass(const MachineFunction &MF, unsigned Kind)
98 const {
99 return &MSP430::GR16RegClass;
100 }
101
102 bool
eliminateFrameIndex(MachineBasicBlock::iterator II,int SPAdj,unsigned FIOperandNum,RegScavenger * RS) const103 MSP430RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
104 int SPAdj, unsigned FIOperandNum,
105 RegScavenger *RS) const {
106 assert(SPAdj == 0 && "Unexpected");
107
108 MachineInstr &MI = *II;
109 MachineBasicBlock &MBB = *MI.getParent();
110 MachineFunction &MF = *MBB.getParent();
111 const MSP430FrameLowering *TFI = getFrameLowering(MF);
112 DebugLoc dl = MI.getDebugLoc();
113 int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
114
115 unsigned BasePtr = (TFI->hasFP(MF) ? MSP430::R4 : MSP430::SP);
116 int Offset = MF.getFrameInfo().getObjectOffset(FrameIndex);
117
118 // Skip the saved PC
119 Offset += 2;
120
121 if (!TFI->hasFP(MF))
122 Offset += MF.getFrameInfo().getStackSize();
123 else
124 Offset += 2; // Skip the saved FP
125
126 // Fold imm into offset
127 Offset += MI.getOperand(FIOperandNum + 1).getImm();
128
129 if (MI.getOpcode() == MSP430::ADDframe) {
130 // This is actually "load effective address" of the stack slot
131 // instruction. We have only two-address instructions, thus we need to
132 // expand it into mov + add
133 const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
134
135 MI.setDesc(TII.get(MSP430::MOV16rr));
136 MI.getOperand(FIOperandNum).ChangeToRegister(BasePtr, false);
137
138 if (Offset == 0)
139 return false;
140
141 // We need to materialize the offset via add instruction.
142 Register DstReg = MI.getOperand(0).getReg();
143 if (Offset < 0)
144 BuildMI(MBB, std::next(II), dl, TII.get(MSP430::SUB16ri), DstReg)
145 .addReg(DstReg).addImm(-Offset);
146 else
147 BuildMI(MBB, std::next(II), dl, TII.get(MSP430::ADD16ri), DstReg)
148 .addReg(DstReg).addImm(Offset);
149
150 return false;
151 }
152
153 MI.getOperand(FIOperandNum).ChangeToRegister(BasePtr, false);
154 MI.getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);
155 return false;
156 }
157
getFrameRegister(const MachineFunction & MF) const158 Register MSP430RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
159 const MSP430FrameLowering *TFI = getFrameLowering(MF);
160 return TFI->hasFP(MF) ? MSP430::R4 : MSP430::SP;
161 }
162