1//===-- SystemZFrameLowering.h - Frame lowering for SystemZ -----*- C++ -*-===//
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#ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZFRAMELOWERING_H
10#define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZFRAMELOWERING_H
11
12#include "MCTargetDesc/SystemZMCTargetDesc.h"
13#include "SystemZInstrBuilder.h"
14#include "SystemZMachineFunctionInfo.h"
15#include "llvm/ADT/IndexedMap.h"
16#include "llvm/CodeGen/TargetFrameLowering.h"
17#include "llvm/Support/TypeSize.h"
18
19namespace llvm {
20class SystemZSubtarget;
21
22class SystemZFrameLowering : public TargetFrameLowering {
23public:
24 SystemZFrameLowering(StackDirection D, Align StackAl, int LAO, Align TransAl,
25 bool StackReal, unsigned PointerSize);
26
27 static std::unique_ptr<SystemZFrameLowering>
28 create(const SystemZSubtarget &STI);
29
30 // Override TargetFrameLowering.
31 bool allocateScavengingFrameIndexesNearIncomingSP(
32 const MachineFunction &MF) const override {
33 // SystemZ wants normal register scavenging slots, as close to the stack or
34 // frame pointer as possible.
35 // The default implementation assumes an x86-like layout, where the frame
36 // pointer is at the opposite end of the frame from the stack pointer.
37 // This meant that when frame pointer elimination was disabled,
38 // the slots ended up being as close as possible to the incoming
39 // stack pointer, which is the opposite of what we want on SystemZ.
40 return false;
41 }
42
43 bool hasReservedCallFrame(const MachineFunction &MF) const override;
44
45 // Return the offset of the backchain.
46 virtual unsigned getBackchainOffset(MachineFunction &MF) const = 0;
47
48 // Return the offset of the return address.
49 virtual int getReturnAddressOffset(MachineFunction &MF) const = 0;
50
51 // Get or create the frame index of where the old frame pointer is stored.
52 virtual int getOrCreateFramePointerSaveIndex(MachineFunction &MF) const = 0;
53
54 // Return the size of a pointer (in bytes).
55 unsigned getPointerSize() const { return PointerSize; }
56
57private:
58 unsigned PointerSize;
59};
60
61class SystemZELFFrameLowering : public SystemZFrameLowering {
62 IndexedMap<unsigned> RegSpillOffsets;
63
64public:
65 SystemZELFFrameLowering(unsigned PointerSize);
66
67 // Override TargetFrameLowering.
68 bool
69 assignCalleeSavedSpillSlots(MachineFunction &MF,
70 const TargetRegisterInfo *TRI,
71 std::vector<CalleeSavedInfo> &CSI) const override;
72 void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
73 RegScavenger *RS) const override;
74 bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
75 MachineBasicBlock::iterator MBBI,
76 ArrayRef<CalleeSavedInfo> CSI,
77 const TargetRegisterInfo *TRI) const override;
78 bool
79 restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
80 MachineBasicBlock::iterator MBBII,
81 MutableArrayRef<CalleeSavedInfo> CSI,
82 const TargetRegisterInfo *TRI) const override;
83 void processFunctionBeforeFrameFinalized(MachineFunction &MF,
84 RegScavenger *RS) const override;
85 void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
86 void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
87 void inlineStackProbe(MachineFunction &MF,
88 MachineBasicBlock &PrologMBB) const override;
89 StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
90 Register &FrameReg) const override;
91 void
92 orderFrameObjects(const MachineFunction &MF,
93 SmallVectorImpl<int> &ObjectsToAllocate) const override;
94
95 // Return the byte offset from the incoming stack pointer of Reg's
96 // ABI-defined save slot. Return 0 if no slot is defined for Reg. Adjust
97 // the offset in case MF has packed-stack.
98 unsigned getRegSpillOffset(MachineFunction &MF, Register Reg) const;
99
100 bool usePackedStack(MachineFunction &MF) const;
101
102 // Return the offset of the backchain.
103 unsigned getBackchainOffset(MachineFunction &MF) const override {
104 // The back chain is stored topmost with packed-stack.
105 return usePackedStack(MF) ? SystemZMC::ELFCallFrameSize - 8 : 0;
106 }
107
108 // Return the offset of the return address.
109 int getReturnAddressOffset(MachineFunction &MF) const override {
110 return (usePackedStack(MF) ? -2 : 14) * getPointerSize();
111 }
112
113 // Get or create the frame index of where the old frame pointer is stored.
114 int getOrCreateFramePointerSaveIndex(MachineFunction &MF) const override;
115
116protected:
117 bool hasFPImpl(const MachineFunction &MF) const override;
118};
119
120class SystemZXPLINKFrameLowering : public SystemZFrameLowering {
121 IndexedMap<unsigned> RegSpillOffsets;
122
123public:
124 SystemZXPLINKFrameLowering(unsigned PointerSize);
125
126 bool
127 assignCalleeSavedSpillSlots(MachineFunction &MF,
128 const TargetRegisterInfo *TRI,
129 std::vector<CalleeSavedInfo> &CSI) const override;
130
131 void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
132 RegScavenger *RS) const override;
133
134 bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
135 MachineBasicBlock::iterator MBBI,
136 ArrayRef<CalleeSavedInfo> CSI,
137 const TargetRegisterInfo *TRI) const override;
138
139 bool
140 restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
141 MachineBasicBlock::iterator MBBII,
142 MutableArrayRef<CalleeSavedInfo> CSI,
143 const TargetRegisterInfo *TRI) const override;
144
145 void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
146
147 void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
148
149 void inlineStackProbe(MachineFunction &MF,
150 MachineBasicBlock &PrologMBB) const override;
151
152 void processFunctionBeforeFrameFinalized(MachineFunction &MF,
153 RegScavenger *RS) const override;
154
155 void determineFrameLayout(MachineFunction &MF) const;
156
157 // Return the offset of the backchain.
158 unsigned getBackchainOffset(MachineFunction &MF) const override {
159 // The back chain is always the first element of the frame.
160 return 0;
161 }
162
163 // Return the offset of the return address.
164 int getReturnAddressOffset(MachineFunction &MF) const override {
165 return 3 * getPointerSize();
166 }
167
168 // Get or create the frame index of where the old frame pointer is stored.
169 int getOrCreateFramePointerSaveIndex(MachineFunction &MF) const override;
170
171protected:
172 bool hasFPImpl(const MachineFunction &MF) const override;
173};
174} // end namespace llvm
175
176#endif
177