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
|
//===- LiveRegUnits.cpp - Register Unit Set -------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
/// \file This file imlements the LiveRegUnits set.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/LiveRegUnits.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBundle.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
using namespace llvm;
void LiveRegUnits::removeRegsNotPreserved(const uint32_t *RegMask) {
for (unsigned U = 0, E = TRI->getNumRegUnits(); U != E; ++U) {
for (MCRegUnitRootIterator RootReg(U, TRI); RootReg.isValid(); ++RootReg) {
if (MachineOperand::clobbersPhysReg(RegMask, *RootReg))
Units.reset(U);
}
}
}
void LiveRegUnits::addRegsInMask(const uint32_t *RegMask) {
for (unsigned U = 0, E = TRI->getNumRegUnits(); U != E; ++U) {
for (MCRegUnitRootIterator RootReg(U, TRI); RootReg.isValid(); ++RootReg) {
if (MachineOperand::clobbersPhysReg(RegMask, *RootReg))
Units.set(U);
}
}
}
void LiveRegUnits::stepBackward(const MachineInstr &MI) {
// Remove defined registers and regmask kills from the set.
for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
if (O->isReg()) {
if (!O->isDef() || O->isDebug())
continue;
unsigned Reg = O->getReg();
if (!TargetRegisterInfo::isPhysicalRegister(Reg))
continue;
removeReg(Reg);
} else if (O->isRegMask())
removeRegsNotPreserved(O->getRegMask());
}
// Add uses to the set.
for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
if (!O->isReg() || !O->readsReg() || O->isDebug())
continue;
unsigned Reg = O->getReg();
if (!TargetRegisterInfo::isPhysicalRegister(Reg))
continue;
addReg(Reg);
}
}
void LiveRegUnits::accumulate(const MachineInstr &MI) {
// Add defs, uses and regmask clobbers to the set.
for (ConstMIBundleOperands O(MI); O.isValid(); ++O) {
if (O->isReg()) {
unsigned Reg = O->getReg();
if (!TargetRegisterInfo::isPhysicalRegister(Reg))
continue;
if (!O->isDef() && !O->readsReg())
continue;
addReg(Reg);
} else if (O->isRegMask())
addRegsInMask(O->getRegMask());
}
}
/// Add live-in registers of basic block \p MBB to \p LiveUnits.
static void addBlockLiveIns(LiveRegUnits &LiveUnits,
const MachineBasicBlock &MBB) {
for (const auto &LI : MBB.liveins())
LiveUnits.addRegMasked(LI.PhysReg, LI.LaneMask);
}
/// Adds all callee saved registers to \p LiveUnits.
static void addCalleeSavedRegs(LiveRegUnits &LiveUnits,
const MachineFunction &MF) {
const MachineRegisterInfo &MRI = MF.getRegInfo();
for (const MCPhysReg *CSR = MRI.getCalleeSavedRegs(); CSR && *CSR; ++CSR)
LiveUnits.addReg(*CSR);
}
void LiveRegUnits::addPristines(const MachineFunction &MF) {
const MachineFrameInfo &MFI = MF.getFrameInfo();
if (!MFI.isCalleeSavedInfoValid())
return;
/// This function will usually be called on an empty object, handle this
/// as a special case.
if (empty()) {
/// Add all callee saved regs, then remove the ones that are saved and
/// restored.
addCalleeSavedRegs(*this, MF);
/// Remove the ones that are not saved/restored; they are pristine.
for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
removeReg(Info.getReg());
return;
}
/// If a callee-saved register that is not pristine is already present
/// in the set, we should make sure that it stays in it. Precompute the
/// set of pristine registers in a separate object.
/// Add all callee saved regs, then remove the ones that are saved+restored.
LiveRegUnits Pristine(*TRI);
addCalleeSavedRegs(Pristine, MF);
/// Remove the ones that are not saved/restored; they are pristine.
for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
Pristine.removeReg(Info.getReg());
addUnits(Pristine.getBitVector());
}
void LiveRegUnits::addLiveOuts(const MachineBasicBlock &MBB) {
const MachineFunction &MF = *MBB.getParent();
addPristines(MF);
// To get the live-outs we simply merge the live-ins of all successors.
for (const MachineBasicBlock *Succ : MBB.successors())
addBlockLiveIns(*this, *Succ);
// For the return block: Add all callee saved registers.
if (MBB.isReturnBlock()) {
const MachineFrameInfo &MFI = MF.getFrameInfo();
if (MFI.isCalleeSavedInfoValid())
addCalleeSavedRegs(*this, MF);
}
}
void LiveRegUnits::addLiveIns(const MachineBasicBlock &MBB) {
const MachineFunction &MF = *MBB.getParent();
addPristines(MF);
addBlockLiveIns(*this, MBB);
}
|
