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 MF.getTarget().Options.DisableFramePointerElim(MF) ||
88 MF.getFrameInfo()->hasVarSizedObjects();
91 void XCoreFrameLowering::emitPrologue(MachineFunction &MF) const {
92 MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
93 MachineBasicBlock::iterator MBBI = MBB.begin();
94 MachineFrameInfo *MFI = MF.getFrameInfo();
95 MachineModuleInfo *MMI = &MF.getMMI();
96 const XCoreRegisterInfo *RegInfo =
97 static_cast<const XCoreRegisterInfo*>(MF.getTarget().getRegisterInfo());
98 const XCoreInstrInfo &TII =
99 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
100 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
101 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
104 bool Nested = MF.getFunction()->
105 getAttributes().hasAttrSomewhere(Attribute::Nest);
108 loadFromStack(MBB, MBBI, XCore::R11, 0, dl, TII);
111 // Work out frame sizes.
112 int FrameSize = MFI->getStackSize();
113 assert(FrameSize%4 == 0 && "Misaligned frame size");
116 bool isU6 = isImmU6(FrameSize);
118 if (!isU6 && !isImmU16(FrameSize)) {
119 // FIXME could emit multiple instructions.
120 report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
122 bool emitFrameMoves = RegInfo->needsFrameMoves(MF);
124 // Do we need to allocate space on the stack?
126 bool saveLR = XFI->getUsesLR();
127 bool LRSavedOnEntry = false;
129 if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
130 Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
131 MBB.addLiveIn(XCore::LR);
133 LRSavedOnEntry = true;
135 Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
137 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
139 if (emitFrameMoves) {
140 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
142 // Show update of SP.
143 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
144 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
146 MachineLocation SPDst(MachineLocation::VirtualFP);
147 MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
148 Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
150 if (LRSavedOnEntry) {
151 MachineLocation CSDst(MachineLocation::VirtualFP, 0);
152 MachineLocation CSSrc(XCore::LR);
153 Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
157 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
158 storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
159 MBB.addLiveIn(XCore::LR);
161 if (emitFrameMoves) {
162 MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
163 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
164 MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
165 MachineLocation CSSrc(XCore::LR);
166 MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
172 // Save R10 to the stack.
173 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
174 storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
175 // R10 is live-in. It is killed at the spill.
176 MBB.addLiveIn(XCore::R10);
177 if (emitFrameMoves) {
178 MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
179 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
180 MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
181 MachineLocation CSSrc(XCore::R10);
182 MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
184 // Set the FP from the SP.
185 unsigned FramePtr = XCore::R10;
186 BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
188 if (emitFrameMoves) {
189 // Show FP is now valid.
190 MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
191 BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
192 MachineLocation SPDst(FramePtr);
193 MachineLocation SPSrc(MachineLocation::VirtualFP);
194 MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
198 if (emitFrameMoves) {
199 // Frame moves for callee saved.
200 std::vector<MachineMove> &Moves = MMI->getFrameMoves();
201 std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
202 XFI->getSpillLabels();
203 for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
204 MCSymbol *SpillLabel = SpillLabels[I].first;
205 CalleeSavedInfo &CSI = SpillLabels[I].second;
206 int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
207 unsigned Reg = CSI.getReg();
208 MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
209 MachineLocation CSSrc(Reg);
210 Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
215 void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
216 MachineBasicBlock &MBB) const {
217 MachineFrameInfo *MFI = MF.getFrameInfo();
218 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
219 const XCoreInstrInfo &TII =
220 *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
221 DebugLoc dl = MBBI->getDebugLoc();
225 // Restore the stack pointer.
226 unsigned FramePtr = XCore::R10;
227 BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
231 // Work out frame sizes.
232 int FrameSize = MFI->getStackSize();
234 assert(FrameSize%4 == 0 && "Misaligned frame size");
238 bool isU6 = isImmU6(FrameSize);
240 if (!isU6 && !isImmU16(FrameSize)) {
241 // FIXME could emit multiple instructions.
242 report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
246 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
250 int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
251 FPSpillOffset += FrameSize*4;
252 loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
254 bool restoreLR = XFI->getUsesLR();
255 if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
256 int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
257 LRSpillOffset += FrameSize*4;
258 loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
262 // Fold prologue into return instruction
263 assert(MBBI->getOpcode() == XCore::RETSP_u6
264 || MBBI->getOpcode() == XCore::RETSP_lu6);
265 int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
266 BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
269 int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
270 BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
275 bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
276 MachineBasicBlock::iterator MI,
277 const std::vector<CalleeSavedInfo> &CSI,
278 const TargetRegisterInfo *TRI) const {
282 MachineFunction *MF = MBB.getParent();
283 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
285 XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
286 bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);
289 if (MI != MBB.end()) DL = MI->getDebugLoc();
291 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
292 it != CSI.end(); ++it) {
293 // Add the callee-saved register as live-in. It's killed at the spill.
294 MBB.addLiveIn(it->getReg());
296 unsigned Reg = it->getReg();
297 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
298 TII.storeRegToStackSlot(MBB, MI, Reg, true,
299 it->getFrameIdx(), RC, TRI);
300 if (emitFrameMoves) {
301 MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
302 BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
303 XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
309 bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
310 MachineBasicBlock::iterator MI,
311 const std::vector<CalleeSavedInfo> &CSI,
312 const TargetRegisterInfo *TRI) const{
313 MachineFunction *MF = MBB.getParent();
314 const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
316 bool AtStart = MI == MBB.begin();
317 MachineBasicBlock::iterator BeforeI = MI;
320 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
321 it != CSI.end(); ++it) {
322 unsigned Reg = it->getReg();
323 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
324 TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
326 assert(MI != MBB.begin() &&
327 "loadRegFromStackSlot didn't insert any code!");
328 // Insert in reverse order. loadRegFromStackSlot can insert multiple
341 XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
342 RegScavenger *RS) const {
343 MachineFrameInfo *MFI = MF.getFrameInfo();
344 const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
345 bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
346 const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
347 XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
349 MF.getRegInfo().setPhysRegUnused(XCore::LR);
351 bool isVarArg = MF.getFunction()->isVarArg();
354 // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
355 FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
357 FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
360 XFI->setUsesLR(FrameIdx);
361 XFI->setLRSpillSlot(FrameIdx);
363 if (RegInfo->requiresRegisterScavenging(MF)) {
364 // Reserve a slot close to SP or frame pointer.
365 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
370 // A callee save register is used to hold the FP.
371 // This needs saving / restoring in the epilogue / prologue.
372 XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
378 void XCoreFrameLowering::
379 processFunctionBeforeFrameFinalized(MachineFunction &MF) const {