1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
//===-- Mips16FrameLowering.cpp - Mips16 Frame Information ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Mips16 implementation of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#include "Mips16FrameLowering.h"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "Mips16InstrInfo.h"
#include "MipsInstrInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
void Mips16FrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
const Mips16InstrInfo &TII =
*static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
uint64_t StackSize = MFI->getStackSize();
// No need to allocate space on the stack.
if (StackSize == 0 && !MFI->adjustsStack()) return;
MachineModuleInfo &MMI = MF.getMMI();
std::vector<MachineMove> &Moves = MMI.getFrameMoves();
MachineLocation DstML, SrcML;
// Adjust stack.
TII.makeFrame(Mips::SP, StackSize, MBB, MBBI);
// emit ".cfi_def_cfa_offset StackSize"
MCSymbol *AdjustSPLabel = MMI.getContext().CreateTempSymbol();
BuildMI(MBB, MBBI, dl,
TII.get(TargetOpcode::PROLOG_LABEL)).addSym(AdjustSPLabel);
DstML = MachineLocation(MachineLocation::VirtualFP);
SrcML = MachineLocation(MachineLocation::VirtualFP, -StackSize);
Moves.push_back(MachineMove(AdjustSPLabel, DstML, SrcML));
MCSymbol *CSLabel = MMI.getContext().CreateTempSymbol();
BuildMI(MBB, MBBI, dl,
TII.get(TargetOpcode::PROLOG_LABEL)).addSym(CSLabel);
DstML = MachineLocation(MachineLocation::VirtualFP, -8);
SrcML = MachineLocation(Mips::S1);
Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
DstML = MachineLocation(MachineLocation::VirtualFP, -12);
SrcML = MachineLocation(Mips::S0);
Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
DstML = MachineLocation(MachineLocation::VirtualFP, -4);
SrcML = MachineLocation(Mips::RA);
Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
if (hasFP(MF))
BuildMI(MBB, MBBI, dl, TII.get(Mips::MoveR3216), Mips::S0)
.addReg(Mips::SP);
}
void Mips16FrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
MachineFrameInfo *MFI = MF.getFrameInfo();
const Mips16InstrInfo &TII =
*static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
DebugLoc dl = MBBI->getDebugLoc();
uint64_t StackSize = MFI->getStackSize();
if (!StackSize)
return;
if (hasFP(MF))
BuildMI(MBB, MBBI, dl, TII.get(Mips::Move32R16), Mips::SP)
.addReg(Mips::S0);
// Adjust stack.
// assumes stacksize multiple of 8
TII.restoreFrame(Mips::SP, StackSize, MBB, MBBI);
}
bool Mips16FrameLowering::
spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
MachineFunction *MF = MBB.getParent();
MachineBasicBlock *EntryBlock = MF->begin();
//
// Registers RA, S0,S1 are the callee saved registers and they
// will be saved with the "save" instruction
// during emitPrologue
//
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
// Add the callee-saved register as live-in. Do not add if the register is
// RA and return address is taken, because it has already been added in
// method MipsTargetLowering::LowerRETURNADDR.
// It's killed at the spill, unless the register is RA and return address
// is taken.
unsigned Reg = CSI[i].getReg();
bool IsRAAndRetAddrIsTaken = (Reg == Mips::RA)
&& MF->getFrameInfo()->isReturnAddressTaken();
if (!IsRAAndRetAddrIsTaken)
EntryBlock->addLiveIn(Reg);
}
return true;
}
bool Mips16FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
//
// Registers RA,S0,S1 are the callee saved registers and they will be restored
// with the restore instruction during emitEpilogue.
// We need to override this virtual function, otherwise llvm will try and
// restore the registers on it's on from the stack.
//
return true;
}
// Eliminate ADJCALLSTACKDOWN, ADJCALLSTACKUP pseudo instructions
void Mips16FrameLowering::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (!hasReservedCallFrame(MF)) {
int64_t Amount = I->getOperand(0).getImm();
if (I->getOpcode() == Mips::ADJCALLSTACKDOWN)
Amount = -Amount;
const Mips16InstrInfo &TII =
*static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
TII.adjustStackPtr(Mips::SP, Amount, MBB, I);
}
MBB.erase(I);
}
bool
Mips16FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
// Reserve call frame if the size of the maximum call frame fits into 15-bit
// immediate field and there are no variable sized objects on the stack.
return isInt<15>(MFI->getMaxCallFrameSize()) && !MFI->hasVarSizedObjects();
}
void Mips16FrameLowering::
processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
MF.getRegInfo().setPhysRegUsed(Mips::RA);
MF.getRegInfo().setPhysRegUsed(Mips::S0);
MF.getRegInfo().setPhysRegUsed(Mips::S1);
}
const MipsFrameLowering *
llvm::createMips16FrameLowering(const MipsSubtarget &ST) {
return new Mips16FrameLowering(ST);
}
|
