1 //===-- XCoreFrameLowering.cpp - Frame info for XCore Target --------------===//
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 XCore frame information that doesn't fit anywhere else
13 //===----------------------------------------------------------------------===//
15 #include "XCoreFrameLowering.h"
17 #include "XCoreInstrInfo.h"
18 #include "XCoreMachineFunctionInfo.h"
19 #include "llvm/Function.h"
20 #include "llvm/CodeGen/MachineFrameInfo.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineInstrBuilder.h"
23 #include "llvm/CodeGen/MachineModuleInfo.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/CodeGen/RegisterScavenging.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/Target/TargetOptions.h"
28 #include "llvm/Support/ErrorHandling.h"
32 // helper functions. FIXME: Eliminate.
33 static inline bool isImmUs(unsigned val) {
37 static inline bool isImmU6(unsigned val) {
38 return val < (1 << 6);
41 static inline bool isImmU16(unsigned val) {
42 return val < (1 << 16);
45 static void loadFromStack(MachineBasicBlock &MBB,
46 MachineBasicBlock::iterator I,
47 unsigned DstReg, int Offset, DebugLoc dl,
48 const TargetInstrInfo &TII) {
49 assert(Offset%4 == 0 && "Misaligned stack offset");
51 bool isU6 = isImmU6(Offset);
52 if (!isU6 && !isImmU16(Offset))
53 report_fatal_error("loadFromStack offset too big " + Twine(Offset));
54 int Opcode = isU6 ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
55 BuildMI(MBB, I, dl, TII.get(Opcode), DstReg)
60 static void storeToStack(MachineBasicBlock &MBB,
61 MachineBasicBlock::iterator I,
62 unsigned SrcReg, int Offset, DebugLoc dl,
63 const TargetInstrInfo &TII) {
64 assert(Offset%4 == 0 && "Misaligned stack offset");
66 bool isU6 = isImmU6(Offset);
67 if (!isU6 && !isImmU16(Offset))
68 report_fatal_error("storeToStack offset too big " + Twine(Offset));
69 int Opcode = isU6 ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
70 BuildMI(MBB, I, dl, TII.get(Opcode))
76 //===----------------------------------------------------------------------===//
77 // XCoreFrameLowering:
78 //===----------------------------------------------------------------------===//
80 XCoreFrameLowering::XCoreFrameLowering(const XCoreSubtarget &sti)
81 : TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 4, 0) {
85 bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const {
86 return MF.getTarget().Options.DisableFramePointerElim(MF) ||
87 MF.getFrameInfo()->hasVarSizedObjects();
90 void XCoreFrameLowering::emitPrologue(MachineFunction &MF) const {
91 MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
92 MachineBasicBlock::iterator MBBI = MBB.begin();
93 MachineFrameInfo *MFI = MF.getFrameInfo();
94 MachineModuleInfo *MMI = &MF.getMMI();
95 const XCoreInstrInfo &TII =
96 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
97 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
98 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
101 bool Nested = MF.getFunction()->
102 getAttributes().hasAttrSomewhere(Attribute::Nest);
105 loadFromStack(MBB, MBBI, XCore::R11, 0, dl, TII);
108 // Work out frame sizes.
109 int FrameSize = MFI->getStackSize();
110 assert(FrameSize%4 == 0 && "Misaligned frame size");
113 bool isU6 = isImmU6(FrameSize);
115 if (!isU6 && !isImmU16(FrameSize)) {
116 // FIXME could emit multiple instructions.
117 report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
119 bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(MF);
121 // Do we need to allocate space on the stack?
123 bool saveLR = XFI->getUsesLR();
124 bool LRSavedOnEntry = false;
126 if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
127 Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
128 MBB.addLiveIn(XCore::LR);
130 LRSavedOnEntry = true;
132 Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
134 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
136 if (emitFrameMoves) {
137 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
139 // Show update of SP.
140 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
141 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
143 MachineLocation SPDst(MachineLocation::VirtualFP);
144 MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
145 Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
147 if (LRSavedOnEntry) {
148 MachineLocation CSDst(MachineLocation::VirtualFP, 0);
149 MachineLocation CSSrc(XCore::LR);
150 Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
154 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
155 storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
156 MBB.addLiveIn(XCore::LR);
158 if (emitFrameMoves) {
159 MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
160 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
161 MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
162 MachineLocation CSSrc(XCore::LR);
163 MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
169 // Save R10 to the stack.
170 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
171 storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
172 // R10 is live-in. It is killed at the spill.
173 MBB.addLiveIn(XCore::R10);
174 if (emitFrameMoves) {
175 MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
176 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
177 MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
178 MachineLocation CSSrc(XCore::R10);
179 MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
181 // Set the FP from the SP.
182 unsigned FramePtr = XCore::R10;
183 BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
185 if (emitFrameMoves) {
186 // Show FP is now valid.
187 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
188 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
189 MachineLocation SPDst(FramePtr);
190 MachineLocation SPSrc(MachineLocation::VirtualFP);
191 MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
195 if (emitFrameMoves) {
196 // Frame moves for callee saved.
197 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
198 std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
199 XFI->getSpillLabels();
200 for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
201 MCSymbol *SpillLabel = SpillLabels[I].first;
202 CalleeSavedInfo &CSI = SpillLabels[I].second;
203 int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
204 unsigned Reg = CSI.getReg();
205 MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
206 MachineLocation CSSrc(Reg);
207 Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
212 void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
213 MachineBasicBlock &MBB) const {
214 MachineFrameInfo *MFI = MF.getFrameInfo();
215 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
216 const XCoreInstrInfo &TII =
217 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
218 DebugLoc dl = MBBI->getDebugLoc();
222 // Restore the stack pointer.
223 unsigned FramePtr = XCore::R10;
224 BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
228 // Work out frame sizes.
229 int FrameSize = MFI->getStackSize();
231 assert(FrameSize%4 == 0 && "Misaligned frame size");
235 bool isU6 = isImmU6(FrameSize);
237 if (!isU6 && !isImmU16(FrameSize)) {
238 // FIXME could emit multiple instructions.
239 report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
243 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
247 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
248 FPSpillOffset += FrameSize*4;
249 loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
251 bool restoreLR = XFI->getUsesLR();
252 if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
253 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
254 LRSpillOffset += FrameSize*4;
255 loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
259 // Fold prologue into return instruction
260 assert(MBBI->getOpcode() == XCore::RETSP_u6
261 || MBBI->getOpcode() == XCore::RETSP_lu6);
262 int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
263 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
266 int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
267 BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
272 bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
273 MachineBasicBlock::iterator MI,
274 const std::vector<CalleeSavedInfo> &CSI,
275 const TargetRegisterInfo *TRI) const {
279 MachineFunction *MF = MBB.getParent();
280 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
282 XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
283 bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);
286 if (MI != MBB.end()) DL = MI->getDebugLoc();
288 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
289 it != CSI.end(); ++it) {
290 // Add the callee-saved register as live-in. It's killed at the spill.
291 MBB.addLiveIn(it->getReg());
293 unsigned Reg = it->getReg();
294 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
295 TII.storeRegToStackSlot(MBB, MI, Reg, true,
296 it->getFrameIdx(), RC, TRI);
297 if (emitFrameMoves) {
298 MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
299 BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
300 XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
306 bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
307 MachineBasicBlock::iterator MI,
308 const std::vector<CalleeSavedInfo> &CSI,
309 const TargetRegisterInfo *TRI) const{
310 MachineFunction *MF = MBB.getParent();
311 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
313 bool AtStart = MI == MBB.begin();
314 MachineBasicBlock::iterator BeforeI = MI;
317 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
318 it != CSI.end(); ++it) {
319 unsigned Reg = it->getReg();
320 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
321 TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
323 assert(MI != MBB.begin() &&
324 "loadRegFromStackSlot didn't insert any code!");
325 // Insert in reverse order. loadRegFromStackSlot can insert multiple
338 XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
339 RegScavenger *RS) const {
340 MachineFrameInfo *MFI = MF.getFrameInfo();
341 const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
342 bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
343 const TargetRegisterClass *RC = &XCore::GRRegsRegClass;
344 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
346 MF.getRegInfo().setPhysRegUnused(XCore::LR);
348 bool isVarArg = MF.getFunction()->isVarArg();
351 // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
352 FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
354 FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
357 XFI->setUsesLR(FrameIdx);
358 XFI->setLRSpillSlot(FrameIdx);
360 if (RegInfo->requiresRegisterScavenging(MF)) {
361 // Reserve a slot close to SP or frame pointer.
362 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
367 // A callee save register is used to hold the FP.
368 // This needs saving / restoring in the epilogue / prologue.
369 XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
375 void XCoreFrameLowering::
376 processFunctionBeforeFrameFinalized(MachineFunction &MF) const {