1 //===- SystemZRegisterInfo.cpp - SystemZ Register Information -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the SystemZ implementation of the TargetRegisterInfo class.
12 //===----------------------------------------------------------------------===//
15 #include "SystemZInstrInfo.h"
16 #include "SystemZMachineFunctionInfo.h"
17 #include "SystemZRegisterInfo.h"
18 #include "SystemZSubtarget.h"
19 #include "llvm/CodeGen/MachineInstrBuilder.h"
20 #include "llvm/CodeGen/MachineFrameInfo.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/Target/TargetFrameInfo.h"
24 #include "llvm/Target/TargetInstrInfo.h"
25 #include "llvm/Target/TargetMachine.h"
26 #include "llvm/Target/TargetOptions.h"
27 #include "llvm/ADT/BitVector.h"
30 SystemZRegisterInfo::SystemZRegisterInfo(SystemZTargetMachine &tm,
31 const SystemZInstrInfo &tii)
32 : SystemZGenRegisterInfo(SystemZ::ADJCALLSTACKUP, SystemZ::ADJCALLSTACKDOWN),
37 SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
38 static const unsigned CalleeSavedRegs[] = {
39 SystemZ::R6D, SystemZ::R7D, SystemZ::R8D, SystemZ::R9D,
40 SystemZ::R10D, SystemZ::R11D, SystemZ::R12D, SystemZ::R13D,
41 SystemZ::R14D, SystemZ::R15D,
42 SystemZ::F8L, SystemZ::F9L, SystemZ::F10L, SystemZ::F11L,
43 SystemZ::F12L, SystemZ::F13L, SystemZ::F14L, SystemZ::F15L,
47 return CalleeSavedRegs;
50 const TargetRegisterClass* const*
51 SystemZRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
52 static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
53 &SystemZ::GR64RegClass, &SystemZ::GR64RegClass,
54 &SystemZ::GR64RegClass, &SystemZ::GR64RegClass,
55 &SystemZ::GR64RegClass, &SystemZ::GR64RegClass,
56 &SystemZ::GR64RegClass, &SystemZ::GR64RegClass,
57 &SystemZ::GR64RegClass, &SystemZ::GR64RegClass,
58 &SystemZ::FP64RegClass, &SystemZ::FP64RegClass,
59 &SystemZ::FP64RegClass, &SystemZ::FP64RegClass,
60 &SystemZ::FP64RegClass, &SystemZ::FP64RegClass,
61 &SystemZ::FP64RegClass, &SystemZ::FP64RegClass, 0
63 return CalleeSavedRegClasses;
66 BitVector SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
67 BitVector Reserved(getNumRegs());
69 Reserved.set(SystemZ::R11D);
70 Reserved.set(SystemZ::R14D);
71 Reserved.set(SystemZ::R15D);
75 /// needsFP - Return true if the specified function should have a dedicated
76 /// frame pointer register. This is true if the function has variable sized
77 /// allocas or if frame pointer elimination is disabled.
78 bool SystemZRegisterInfo::hasFP(const MachineFunction &MF) const {
79 const MachineFrameInfo *MFI = MF.getFrameInfo();
80 return NoFramePointerElim || MFI->hasVarSizedObjects();
83 void SystemZRegisterInfo::
84 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
85 MachineBasicBlock::iterator I) const {
89 int SystemZRegisterInfo::getFrameIndexOffset(MachineFunction &MF, int FI) const {
90 const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
91 MachineFrameInfo *MFI = MF.getFrameInfo();
92 SystemZMachineFunctionInfo *SystemZMFI =
93 MF.getInfo<SystemZMachineFunctionInfo>();
94 int Offset = MFI->getObjectOffset(FI) + MFI->getOffsetAdjustment();
95 uint64_t StackSize = MFI->getStackSize();
97 // Fixed objects are really located in the "previous" frame.
99 StackSize -= SystemZMFI->getCalleeSavedFrameSize();
101 Offset += StackSize - TFI.getOffsetOfLocalArea();
103 // Skip the register save area if we generated the stack frame.
105 Offset -= TFI.getOffsetOfLocalArea();
110 void SystemZRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
111 int SPAdj, RegScavenger *RS) const {
112 assert(SPAdj == 0 && "Unxpected");
115 MachineInstr &MI = *II;
116 MachineFunction &MF = *MI.getParent()->getParent();
117 while (!MI.getOperand(i).isFI()) {
119 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
122 int FrameIndex = MI.getOperand(i).getIndex();
124 unsigned BasePtr = (hasFP(MF) ? SystemZ::R11D : SystemZ::R15D);
126 // This must be part of a rri or ri operand memory reference. Replace the
127 // FrameIndex with base register with BasePtr. Add an offset to the
128 // displacement field.
129 MI.getOperand(i).ChangeToRegister(BasePtr, false);
131 // Offset is a either 12-bit unsigned or 20-bit signed integer.
132 // FIXME: handle "too long" displacements.
133 int Offset = getFrameIndexOffset(MF, FrameIndex) + MI.getOperand(i+1).getImm();
135 // Check whether displacement is too long to fit into 12 bit zext field.
136 if (Offset < 0 || Offset >= 4096)
137 MI.setDesc(TII.getLongDispOpc(MI.getOpcode()));
139 MI.getOperand(i+1).ChangeToImmediate(Offset);
143 SystemZRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
144 RegScavenger *RS) const {
145 // Determine whether R15/R14 will ever be clobbered inside the function. And
146 // if yes - mark it as 'callee' saved.
147 MachineFrameInfo *FFI = MF.getFrameInfo();
148 MachineRegisterInfo &MRI = MF.getRegInfo();
150 // Check whether high FPRs are ever used, if yes - we need to save R15 as
152 static const unsigned HighFPRs[] = {
153 SystemZ::F8L, SystemZ::F9L, SystemZ::F10L, SystemZ::F11L,
154 SystemZ::F12L, SystemZ::F13L, SystemZ::F14L, SystemZ::F15L,
155 SystemZ::F8S, SystemZ::F9S, SystemZ::F10S, SystemZ::F11S,
156 SystemZ::F12S, SystemZ::F13S, SystemZ::F14S, SystemZ::F15S,
159 bool HighFPRsUsed = false;
160 for (unsigned i = 0, e = array_lengthof(HighFPRs); i != e; ++i)
161 HighFPRsUsed |= MRI.isPhysRegUsed(HighFPRs[i]);
164 /* FIXME: function is varargs */
165 /* FIXME: function grabs RA */
166 /* FIXME: function calls eh_return */
167 MRI.setPhysRegUsed(SystemZ::R14D);
171 FFI->getObjectIndexEnd() != 0 || // Contains automatic variables
172 FFI->hasVarSizedObjects() // Function calls dynamic alloca's
173 /* FIXME: function is varargs */)
174 MRI.setPhysRegUsed(SystemZ::R15D);
177 /// emitSPUpdate - Emit a series of instructions to increment / decrement the
178 /// stack pointer by a constant value.
180 void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
181 int64_t NumBytes, const TargetInstrInfo &TII) {
182 // FIXME: Handle different stack sizes here.
183 bool isSub = NumBytes < 0;
184 uint64_t Offset = isSub ? -NumBytes : NumBytes;
185 unsigned Opc = SystemZ::ADD64ri16;
186 uint64_t Chunk = (1LL << 15) - 1;
187 DebugLoc DL = (MBBI != MBB.end() ? MBBI->getDebugLoc() :
188 DebugLoc::getUnknownLoc());
191 uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
193 BuildMI(MBB, MBBI, DL, TII.get(Opc), SystemZ::R15D)
194 .addReg(SystemZ::R15D).addImm((isSub ? -(int64_t)ThisVal : ThisVal));
195 // The PSW implicit def is dead.
196 MI->getOperand(3).setIsDead();
201 void SystemZRegisterInfo::emitPrologue(MachineFunction &MF) const {
202 MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
203 const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
204 MachineFrameInfo *MFI = MF.getFrameInfo();
205 SystemZMachineFunctionInfo *SystemZMFI =
206 MF.getInfo<SystemZMachineFunctionInfo>();
207 MachineBasicBlock::iterator MBBI = MBB.begin();
208 DebugLoc DL = (MBBI != MBB.end() ? MBBI->getDebugLoc() :
209 DebugLoc::getUnknownLoc());
211 // Get the number of bytes to allocate from the FrameInfo.
212 // Note that area for callee-saved stuff is already allocated, thus we need to
213 // 'undo' the stack movement.
214 uint64_t StackSize = MFI->getStackSize();
215 StackSize -= SystemZMFI->getCalleeSavedFrameSize();
217 uint64_t NumBytes = StackSize - TFI.getOffsetOfLocalArea();
219 // Skip the callee-saved push instructions.
220 while (MBBI != MBB.end() &&
221 (MBBI->getOpcode() == SystemZ::MOV64mr ||
222 MBBI->getOpcode() == SystemZ::MOV64mrm))
225 if (MBBI != MBB.end())
226 DL = MBBI->getDebugLoc();
228 // adjust stack pointer: R15 -= numbytes
229 if (StackSize || MFI->hasCalls()) {
230 assert(MF.getRegInfo().isPhysRegUsed(SystemZ::R15D) &&
231 "Invalid stack frame calculation!");
232 emitSPUpdate(MBB, MBBI, -(int64_t)NumBytes, TII);
236 // Update R11 with the new base value...
237 BuildMI(MBB, MBBI, DL, TII.get(SystemZ::MOV64rr), SystemZ::R11D)
238 .addReg(SystemZ::R15D);
240 // Mark the FramePtr as live-in in every block except the entry.
241 for (MachineFunction::iterator I = next(MF.begin()), E = MF.end();
243 I->addLiveIn(SystemZ::R11D);
248 void SystemZRegisterInfo::emitEpilogue(MachineFunction &MF,
249 MachineBasicBlock &MBB) const {
250 const MachineFrameInfo *MFI = MF.getFrameInfo();
251 const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
252 MachineBasicBlock::iterator MBBI = prior(MBB.end());
253 SystemZMachineFunctionInfo *SystemZMFI =
254 MF.getInfo<SystemZMachineFunctionInfo>();
255 unsigned RetOpcode = MBBI->getOpcode();
256 DebugLoc DL = MBBI->getDebugLoc();
259 case SystemZ::RET: break; // These are ok
261 assert(0 && "Can only insert epilog into returning blocks");
264 // Get the number of bytes to allocate from the FrameInfo
265 // Note that area for callee-saved stuff is already allocated, thus we need to
266 // 'undo' the stack movement.
268 MFI->getStackSize() - SystemZMFI->getCalleeSavedFrameSize();
269 uint64_t NumBytes = StackSize - TFI.getOffsetOfLocalArea();
271 // Skip the final terminator instruction.
272 while (MBBI != MBB.begin()) {
273 MachineBasicBlock::iterator PI = prior(MBBI);
275 if (!PI->getDesc().isTerminator())
279 // During callee-saved restores emission stack frame was not yet finialized
280 // (and thus - the stack size was unknown). Tune the offset having full stack
282 if (StackSize || MFI->hasCalls()) {
283 assert((MBBI->getOpcode() == SystemZ::MOV64rmm ||
284 MBBI->getOpcode() == SystemZ::MOV64rm) &&
285 "Expected to see callee-save register restore code");
286 assert(MF.getRegInfo().isPhysRegUsed(SystemZ::R15D) &&
287 "Invalid stack frame calculation!");
290 MachineInstr &MI = *MBBI;
291 while (!MI.getOperand(i).isImm()) {
293 assert(i < MI.getNumOperands() && "Unexpected restore code!");
296 MI.getOperand(i).ChangeToImmediate(NumBytes + MI.getOperand(i).getImm());
300 unsigned SystemZRegisterInfo::getRARegister() const {
301 assert(0 && "What is the return address register");
305 unsigned SystemZRegisterInfo::getFrameRegister(MachineFunction &MF) const {
306 assert(0 && "What is the frame register");
310 unsigned SystemZRegisterInfo::getEHExceptionRegister() const {
311 assert(0 && "What is the exception register");
315 unsigned SystemZRegisterInfo::getEHHandlerRegister() const {
316 assert(0 && "What is the exception handler register");
320 int SystemZRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
321 assert(0 && "What is the dwarf register number");
325 #include "SystemZGenRegisterInfo.inc"