1 //===-- XCoreFrameLowering.cpp - Frame info for XCore Target -----*- 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 XCore frame information that doesn't fit anywhere else
13 //===----------------------------------------------------------------------===//
16 #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),
86 bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const {
87 return DisableFramePointerElim(MF) || 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 XCoreRegisterInfo *RegInfo =
96 static_cast<const XCoreRegisterInfo*>(MF.getTarget().getRegisterInfo());
97 const XCoreInstrInfo &TII =
98 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
99 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
100 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
104 // Work out frame sizes.
105 int FrameSize = MFI->getStackSize();
106 assert(FrameSize%4 == 0 && "Misaligned frame size");
109 bool isU6 = isImmU6(FrameSize);
111 if (!isU6 && !isImmU16(FrameSize)) {
112 // FIXME could emit multiple instructions.
113 report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
115 bool emitFrameMoves = RegInfo->needsFrameMoves(MF);
117 // Do we need to allocate space on the stack?
119 bool saveLR = XFI->getUsesLR();
120 bool LRSavedOnEntry = false;
122 if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
123 Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
124 MBB.addLiveIn(XCore::LR);
126 LRSavedOnEntry = true;
128 Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
130 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
132 if (emitFrameMoves) {
133 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
135 // Show update of SP.
136 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
137 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
139 MachineLocation SPDst(MachineLocation::VirtualFP);
140 MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
141 Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
143 if (LRSavedOnEntry) {
144 MachineLocation CSDst(MachineLocation::VirtualFP, 0);
145 MachineLocation CSSrc(XCore::LR);
146 Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
150 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
151 storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
152 MBB.addLiveIn(XCore::LR);
154 if (emitFrameMoves) {
155 MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
156 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
157 MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
158 MachineLocation CSSrc(XCore::LR);
159 MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
165 // Save R10 to the stack.
166 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
167 storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
168 // R10 is live-in. It is killed at the spill.
169 MBB.addLiveIn(XCore::R10);
170 if (emitFrameMoves) {
171 MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
172 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
173 MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
174 MachineLocation CSSrc(XCore::R10);
175 MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
177 // Set the FP from the SP.
178 unsigned FramePtr = XCore::R10;
179 BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
181 if (emitFrameMoves) {
182 // Show FP is now valid.
183 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
184 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
185 MachineLocation SPDst(FramePtr);
186 MachineLocation SPSrc(MachineLocation::VirtualFP);
187 MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
191 if (emitFrameMoves) {
192 // Frame moves for callee saved.
193 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
194 std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
195 XFI->getSpillLabels();
196 for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
197 MCSymbol *SpillLabel = SpillLabels[I].first;
198 CalleeSavedInfo &CSI = SpillLabels[I].second;
199 int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
200 unsigned Reg = CSI.getReg();
201 MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
202 MachineLocation CSSrc(Reg);
203 Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
208 void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
209 MachineBasicBlock &MBB) const {
210 MachineFrameInfo *MFI = MF.getFrameInfo();
211 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
212 const XCoreInstrInfo &TII =
213 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
214 DebugLoc dl = MBBI->getDebugLoc();
218 // Restore the stack pointer.
219 unsigned FramePtr = XCore::R10;
220 BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
224 // Work out frame sizes.
225 int FrameSize = MFI->getStackSize();
227 assert(FrameSize%4 == 0 && "Misaligned frame size");
231 bool isU6 = isImmU6(FrameSize);
233 if (!isU6 && !isImmU16(FrameSize)) {
234 // FIXME could emit multiple instructions.
235 report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
239 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
243 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
244 FPSpillOffset += FrameSize*4;
245 loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
247 bool restoreLR = XFI->getUsesLR();
248 if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
249 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
250 LRSpillOffset += FrameSize*4;
251 loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
255 // Fold prologue into return instruction
256 assert(MBBI->getOpcode() == XCore::RETSP_u6
257 || MBBI->getOpcode() == XCore::RETSP_lu6);
258 int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
259 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
262 int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
263 BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
268 void XCoreFrameLowering::getInitialFrameState(std::vector<MachineMove> &Moves)
270 // Initial state of the frame pointer is SP.
271 MachineLocation Dst(MachineLocation::VirtualFP);
272 MachineLocation Src(XCore::SP, 0);
273 Moves.push_back(MachineMove(0, Dst, Src));
276 bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
277 MachineBasicBlock::iterator MI,
278 const std::vector<CalleeSavedInfo> &CSI,
279 const TargetRegisterInfo *TRI) const {
283 MachineFunction *MF = MBB.getParent();
284 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
286 XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
287 bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);
290 if (MI != MBB.end()) DL = MI->getDebugLoc();
292 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
293 it != CSI.end(); ++it) {
294 // Add the callee-saved register as live-in. It's killed at the spill.
295 MBB.addLiveIn(it->getReg());
297 unsigned Reg = it->getReg();
298 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
299 TII.storeRegToStackSlot(MBB, MI, Reg, true,
300 it->getFrameIdx(), RC, TRI);
301 if (emitFrameMoves) {
302 MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
303 BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
304 XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
310 bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
311 MachineBasicBlock::iterator MI,
312 const std::vector<CalleeSavedInfo> &CSI,
313 const TargetRegisterInfo *TRI) const{
314 MachineFunction *MF = MBB.getParent();
315 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
317 bool AtStart = MI == MBB.begin();
318 MachineBasicBlock::iterator BeforeI = MI;
321 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
322 it != CSI.end(); ++it) {
323 unsigned Reg = it->getReg();
324 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
325 TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
327 assert(MI != MBB.begin() &&
328 "loadRegFromStackSlot didn't insert any code!");
329 // Insert in reverse order. loadRegFromStackSlot can insert multiple
342 XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
343 RegScavenger *RS) const {
344 MachineFrameInfo *MFI = MF.getFrameInfo();
345 const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
346 bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
347 const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
348 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
350 MF.getRegInfo().setPhysRegUnused(XCore::LR);
352 bool isVarArg = MF.getFunction()->isVarArg();
355 // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
356 FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
358 FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
361 XFI->setUsesLR(FrameIdx);
362 XFI->setLRSpillSlot(FrameIdx);
364 if (RegInfo->requiresRegisterScavenging(MF)) {
365 // Reserve a slot close to SP or frame pointer.
366 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
371 // A callee save register is used to hold the FP.
372 // This needs saving / restoring in the epilogue / prologue.
373 XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
379 void XCoreFrameLowering::
380 processFunctionBeforeFrameFinalized(MachineFunction &MF) const {