1 //===-- PPCRegisterInfo.cpp - PowerPC Register Information ----------------===//
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 PowerPC implementation of the TargetRegisterInfo
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "reginfo"
16 #include "PPCRegisterInfo.h"
18 #include "PPCFrameLowering.h"
19 #include "PPCInstrBuilder.h"
20 #include "PPCMachineFunctionInfo.h"
21 #include "PPCSubtarget.h"
22 #include "llvm/ADT/BitVector.h"
23 #include "llvm/ADT/STLExtras.h"
24 #include "llvm/CodeGen/MachineFrameInfo.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineInstrBuilder.h"
27 #include "llvm/CodeGen/MachineModuleInfo.h"
28 #include "llvm/CodeGen/MachineRegisterInfo.h"
29 #include "llvm/CodeGen/RegisterScavenging.h"
30 #include "llvm/CodeGen/ValueTypes.h"
31 #include "llvm/IR/CallingConv.h"
32 #include "llvm/IR/Constants.h"
33 #include "llvm/IR/Function.h"
34 #include "llvm/IR/Type.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/Debug.h"
37 #include "llvm/Support/ErrorHandling.h"
38 #include "llvm/Support/MathExtras.h"
39 #include "llvm/Support/raw_ostream.h"
40 #include "llvm/Target/TargetFrameLowering.h"
41 #include "llvm/Target/TargetInstrInfo.h"
42 #include "llvm/Target/TargetMachine.h"
43 #include "llvm/Target/TargetOptions.h"
46 #define GET_REGINFO_TARGET_DESC
47 #include "PPCGenRegisterInfo.inc"
52 EnableBasePointer("ppc-use-base-pointer", cl::Hidden, cl::init(true),
53 cl::desc("Enable use of a base pointer for complex stack frames"));
56 AlwaysBasePointer("ppc-always-use-base-pointer", cl::Hidden, cl::init(false),
57 cl::desc("Force the use of a base pointer in every function"));
59 PPCRegisterInfo::PPCRegisterInfo(const PPCSubtarget &ST)
60 : PPCGenRegisterInfo(ST.isPPC64() ? PPC::LR8 : PPC::LR,
62 ST.isPPC64() ? 0 : 1),
64 ImmToIdxMap[PPC::LD] = PPC::LDX; ImmToIdxMap[PPC::STD] = PPC::STDX;
65 ImmToIdxMap[PPC::LBZ] = PPC::LBZX; ImmToIdxMap[PPC::STB] = PPC::STBX;
66 ImmToIdxMap[PPC::LHZ] = PPC::LHZX; ImmToIdxMap[PPC::LHA] = PPC::LHAX;
67 ImmToIdxMap[PPC::LWZ] = PPC::LWZX; ImmToIdxMap[PPC::LWA] = PPC::LWAX;
68 ImmToIdxMap[PPC::LFS] = PPC::LFSX; ImmToIdxMap[PPC::LFD] = PPC::LFDX;
69 ImmToIdxMap[PPC::STH] = PPC::STHX; ImmToIdxMap[PPC::STW] = PPC::STWX;
70 ImmToIdxMap[PPC::STFS] = PPC::STFSX; ImmToIdxMap[PPC::STFD] = PPC::STFDX;
71 ImmToIdxMap[PPC::ADDI] = PPC::ADD4;
72 ImmToIdxMap[PPC::LWA_32] = PPC::LWAX_32;
75 ImmToIdxMap[PPC::LHA8] = PPC::LHAX8; ImmToIdxMap[PPC::LBZ8] = PPC::LBZX8;
76 ImmToIdxMap[PPC::LHZ8] = PPC::LHZX8; ImmToIdxMap[PPC::LWZ8] = PPC::LWZX8;
77 ImmToIdxMap[PPC::STB8] = PPC::STBX8; ImmToIdxMap[PPC::STH8] = PPC::STHX8;
78 ImmToIdxMap[PPC::STW8] = PPC::STWX8; ImmToIdxMap[PPC::STDU] = PPC::STDUX;
79 ImmToIdxMap[PPC::ADDI8] = PPC::ADD8;
82 /// getPointerRegClass - Return the register class to use to hold pointers.
83 /// This is used for addressing modes.
84 const TargetRegisterClass *
85 PPCRegisterInfo::getPointerRegClass(const MachineFunction &MF, unsigned Kind)
87 // Note that PPCInstrInfo::FoldImmediate also directly uses this Kind value
88 // when it checks for ZERO folding.
90 if (Subtarget.isPPC64())
91 return &PPC::G8RC_NOX0RegClass;
92 return &PPC::GPRC_NOR0RegClass;
95 if (Subtarget.isPPC64())
96 return &PPC::G8RCRegClass;
97 return &PPC::GPRCRegClass;
101 PPCRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
102 if (Subtarget.isDarwinABI())
103 return Subtarget.isPPC64() ? (Subtarget.hasAltivec() ?
104 CSR_Darwin64_Altivec_SaveList :
105 CSR_Darwin64_SaveList) :
106 (Subtarget.hasAltivec() ?
107 CSR_Darwin32_Altivec_SaveList :
108 CSR_Darwin32_SaveList);
110 return Subtarget.isPPC64() ? (Subtarget.hasAltivec() ?
111 CSR_SVR464_Altivec_SaveList :
112 CSR_SVR464_SaveList) :
113 (Subtarget.hasAltivec() ?
114 CSR_SVR432_Altivec_SaveList :
115 CSR_SVR432_SaveList);
119 PPCRegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
120 if (Subtarget.isDarwinABI())
121 return Subtarget.isPPC64() ? (Subtarget.hasAltivec() ?
122 CSR_Darwin64_Altivec_RegMask :
123 CSR_Darwin64_RegMask) :
124 (Subtarget.hasAltivec() ?
125 CSR_Darwin32_Altivec_RegMask :
126 CSR_Darwin32_RegMask);
128 return Subtarget.isPPC64() ? (Subtarget.hasAltivec() ?
129 CSR_SVR464_Altivec_RegMask :
130 CSR_SVR464_RegMask) :
131 (Subtarget.hasAltivec() ?
132 CSR_SVR432_Altivec_RegMask :
137 PPCRegisterInfo::getNoPreservedMask() const {
138 return CSR_NoRegs_RegMask;
141 BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
142 BitVector Reserved(getNumRegs());
143 const PPCFrameLowering *PPCFI =
144 static_cast<const PPCFrameLowering*>(MF.getTarget().getFrameLowering());
146 // The ZERO register is not really a register, but the representation of r0
147 // when used in instructions that treat r0 as the constant 0.
148 Reserved.set(PPC::ZERO);
149 Reserved.set(PPC::ZERO8);
151 // The FP register is also not really a register, but is the representation
152 // of the frame pointer register used by ISD::FRAMEADDR.
153 Reserved.set(PPC::FP);
154 Reserved.set(PPC::FP8);
156 // The BP register is also not really a register, but is the representation
157 // of the base pointer register used by setjmp.
158 Reserved.set(PPC::BP);
159 Reserved.set(PPC::BP8);
161 // The counter registers must be reserved so that counter-based loops can
162 // be correctly formed (and the mtctr instructions are not DCE'd).
163 Reserved.set(PPC::CTR);
164 Reserved.set(PPC::CTR8);
166 Reserved.set(PPC::R1);
167 Reserved.set(PPC::LR);
168 Reserved.set(PPC::LR8);
169 Reserved.set(PPC::RM);
171 if (!Subtarget.isDarwinABI() || !Subtarget.hasAltivec())
172 Reserved.set(PPC::VRSAVE);
174 // The SVR4 ABI reserves r2 and r13
175 if (Subtarget.isSVR4ABI()) {
176 Reserved.set(PPC::R2); // System-reserved register
177 Reserved.set(PPC::R13); // Small Data Area pointer register
180 // On PPC64, r13 is the thread pointer. Never allocate this register.
181 if (Subtarget.isPPC64()) {
182 Reserved.set(PPC::R13);
184 Reserved.set(PPC::X1);
185 Reserved.set(PPC::X13);
187 if (PPCFI->needsFP(MF))
188 Reserved.set(PPC::X31);
190 if (hasBasePointer(MF))
191 Reserved.set(PPC::X30);
193 // The 64-bit SVR4 ABI reserves r2 for the TOC pointer.
194 if (Subtarget.isSVR4ABI()) {
195 Reserved.set(PPC::X2);
199 if (PPCFI->needsFP(MF))
200 Reserved.set(PPC::R31);
202 if (hasBasePointer(MF)) {
203 if (Subtarget.isSVR4ABI() && !Subtarget.isPPC64() &&
204 MF.getTarget().getRelocationModel() == Reloc::PIC_)
205 Reserved.set(PPC::R29);
207 Reserved.set(PPC::R30);
210 if (Subtarget.isSVR4ABI() && !Subtarget.isPPC64() &&
211 MF.getTarget().getRelocationModel() == Reloc::PIC_)
212 Reserved.set(PPC::R30);
214 // Reserve Altivec registers when Altivec is unavailable.
215 if (!Subtarget.hasAltivec())
216 for (TargetRegisterClass::iterator I = PPC::VRRCRegClass.begin(),
217 IE = PPC::VRRCRegClass.end(); I != IE; ++I)
224 PPCRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
225 MachineFunction &MF) const {
226 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
227 const unsigned DefaultSafety = 1;
229 switch (RC->getID()) {
232 case PPC::G8RC_NOX0RegClassID:
233 case PPC::GPRC_NOR0RegClassID:
234 case PPC::G8RCRegClassID:
235 case PPC::GPRCRegClassID: {
236 unsigned FP = TFI->hasFP(MF) ? 1 : 0;
237 return 32 - FP - DefaultSafety;
239 case PPC::F8RCRegClassID:
240 case PPC::F4RCRegClassID:
241 case PPC::VRRCRegClassID:
242 return 32 - DefaultSafety;
243 case PPC::CRRCRegClassID:
244 return 8 - DefaultSafety;
248 //===----------------------------------------------------------------------===//
249 // Stack Frame Processing methods
250 //===----------------------------------------------------------------------===//
252 /// lowerDynamicAlloc - Generate the code for allocating an object in the
253 /// current frame. The sequence of code with be in the general form
255 /// addi R0, SP, \#frameSize ; get the address of the previous frame
256 /// stwxu R0, SP, Rnegsize ; add and update the SP with the negated size
257 /// addi Rnew, SP, \#maxCalFrameSize ; get the top of the allocation
259 void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II) const {
260 // Get the instruction.
261 MachineInstr &MI = *II;
262 // Get the instruction's basic block.
263 MachineBasicBlock &MBB = *MI.getParent();
264 // Get the basic block's function.
265 MachineFunction &MF = *MBB.getParent();
266 // Get the frame info.
267 MachineFrameInfo *MFI = MF.getFrameInfo();
268 // Get the instruction info.
269 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
270 // Determine whether 64-bit pointers are used.
271 bool LP64 = Subtarget.isPPC64();
272 DebugLoc dl = MI.getDebugLoc();
274 // Get the maximum call stack size.
275 unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
276 // Get the total frame size.
277 unsigned FrameSize = MFI->getStackSize();
279 // Get stack alignments.
280 unsigned TargetAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
281 unsigned MaxAlign = MFI->getMaxAlignment();
282 assert((maxCallFrameSize & (MaxAlign-1)) == 0 &&
283 "Maximum call-frame size not sufficiently aligned");
285 // Determine the previous frame's address. If FrameSize can't be
286 // represented as 16 bits or we need special alignment, then we load the
287 // previous frame's address from 0(SP). Why not do an addis of the hi?
288 // Because R0 is our only safe tmp register and addi/addis treat R0 as zero.
289 // Constructing the constant and adding would take 3 instructions.
290 // Fortunately, a frame greater than 32K is rare.
291 const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
292 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
293 unsigned Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
295 if (MaxAlign < TargetAlign && isInt<16>(FrameSize)) {
296 BuildMI(MBB, II, dl, TII.get(PPC::ADDI), Reg)
300 BuildMI(MBB, II, dl, TII.get(PPC::LD), Reg)
304 BuildMI(MBB, II, dl, TII.get(PPC::LWZ), Reg)
309 bool KillNegSizeReg = MI.getOperand(1).isKill();
310 unsigned NegSizeReg = MI.getOperand(1).getReg();
312 // Grow the stack and update the stack pointer link, then determine the
313 // address of new allocated space.
315 if (MaxAlign > TargetAlign) {
316 unsigned UnalNegSizeReg = NegSizeReg;
317 NegSizeReg = MF.getRegInfo().createVirtualRegister(G8RC);
319 // Unfortunately, there is no andi, only andi., and we can't insert that
320 // here because we might clobber cr0 while it is live.
321 BuildMI(MBB, II, dl, TII.get(PPC::LI8), NegSizeReg)
322 .addImm(~(MaxAlign-1));
324 unsigned NegSizeReg1 = NegSizeReg;
325 NegSizeReg = MF.getRegInfo().createVirtualRegister(G8RC);
326 BuildMI(MBB, II, dl, TII.get(PPC::AND8), NegSizeReg)
327 .addReg(UnalNegSizeReg, getKillRegState(KillNegSizeReg))
328 .addReg(NegSizeReg1, RegState::Kill);
329 KillNegSizeReg = true;
332 BuildMI(MBB, II, dl, TII.get(PPC::STDUX), PPC::X1)
333 .addReg(Reg, RegState::Kill)
335 .addReg(NegSizeReg, getKillRegState(KillNegSizeReg));
336 BuildMI(MBB, II, dl, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
338 .addImm(maxCallFrameSize);
340 if (MaxAlign > TargetAlign) {
341 unsigned UnalNegSizeReg = NegSizeReg;
342 NegSizeReg = MF.getRegInfo().createVirtualRegister(GPRC);
344 // Unfortunately, there is no andi, only andi., and we can't insert that
345 // here because we might clobber cr0 while it is live.
346 BuildMI(MBB, II, dl, TII.get(PPC::LI), NegSizeReg)
347 .addImm(~(MaxAlign-1));
349 unsigned NegSizeReg1 = NegSizeReg;
350 NegSizeReg = MF.getRegInfo().createVirtualRegister(GPRC);
351 BuildMI(MBB, II, dl, TII.get(PPC::AND), NegSizeReg)
352 .addReg(UnalNegSizeReg, getKillRegState(KillNegSizeReg))
353 .addReg(NegSizeReg1, RegState::Kill);
354 KillNegSizeReg = true;
357 BuildMI(MBB, II, dl, TII.get(PPC::STWUX), PPC::R1)
358 .addReg(Reg, RegState::Kill)
360 .addReg(NegSizeReg, getKillRegState(KillNegSizeReg));
361 BuildMI(MBB, II, dl, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
363 .addImm(maxCallFrameSize);
366 // Discard the DYNALLOC instruction.
370 /// lowerCRSpilling - Generate the code for spilling a CR register. Instead of
371 /// reserving a whole register (R0), we scrounge for one here. This generates
374 /// mfcr rA ; Move the conditional register into GPR rA.
375 /// rlwinm rA, rA, SB, 0, 31 ; Shift the bits left so they are in CR0's slot.
376 /// stw rA, FI ; Store rA to the frame.
378 void PPCRegisterInfo::lowerCRSpilling(MachineBasicBlock::iterator II,
379 unsigned FrameIndex) const {
380 // Get the instruction.
381 MachineInstr &MI = *II; // ; SPILL_CR <SrcReg>, <offset>
382 // Get the instruction's basic block.
383 MachineBasicBlock &MBB = *MI.getParent();
384 MachineFunction &MF = *MBB.getParent();
385 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
386 DebugLoc dl = MI.getDebugLoc();
388 bool LP64 = Subtarget.isPPC64();
389 const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
390 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
392 unsigned Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
393 unsigned SrcReg = MI.getOperand(0).getReg();
395 // We need to store the CR in the low 4-bits of the saved value. First, issue
396 // an MFOCRF to save all of the CRBits and, if needed, kill the SrcReg.
397 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::MFOCRF8 : PPC::MFOCRF), Reg)
398 .addReg(SrcReg, getKillRegState(MI.getOperand(0).isKill()));
400 // If the saved register wasn't CR0, shift the bits left so that they are in
402 if (SrcReg != PPC::CR0) {
404 Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
406 // rlwinm rA, rA, ShiftBits, 0, 31.
407 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::RLWINM8 : PPC::RLWINM), Reg)
408 .addReg(Reg1, RegState::Kill)
409 .addImm(getEncodingValue(SrcReg) * 4)
414 addFrameReference(BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::STW8 : PPC::STW))
415 .addReg(Reg, RegState::Kill),
418 // Discard the pseudo instruction.
422 void PPCRegisterInfo::lowerCRRestore(MachineBasicBlock::iterator II,
423 unsigned FrameIndex) const {
424 // Get the instruction.
425 MachineInstr &MI = *II; // ; <DestReg> = RESTORE_CR <offset>
426 // Get the instruction's basic block.
427 MachineBasicBlock &MBB = *MI.getParent();
428 MachineFunction &MF = *MBB.getParent();
429 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
430 DebugLoc dl = MI.getDebugLoc();
432 bool LP64 = Subtarget.isPPC64();
433 const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
434 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
436 unsigned Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
437 unsigned DestReg = MI.getOperand(0).getReg();
438 assert(MI.definesRegister(DestReg) &&
439 "RESTORE_CR does not define its destination");
441 addFrameReference(BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::LWZ8 : PPC::LWZ),
444 // If the reloaded register isn't CR0, shift the bits right so that they are
445 // in the right CR's slot.
446 if (DestReg != PPC::CR0) {
448 Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
450 unsigned ShiftBits = getEncodingValue(DestReg)*4;
451 // rlwinm r11, r11, 32-ShiftBits, 0, 31.
452 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::RLWINM8 : PPC::RLWINM), Reg)
453 .addReg(Reg1, RegState::Kill).addImm(32-ShiftBits).addImm(0)
457 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::MTOCRF8 : PPC::MTOCRF), DestReg)
458 .addReg(Reg, RegState::Kill);
460 // Discard the pseudo instruction.
464 void PPCRegisterInfo::lowerVRSAVESpilling(MachineBasicBlock::iterator II,
465 unsigned FrameIndex) const {
466 // Get the instruction.
467 MachineInstr &MI = *II; // ; SPILL_VRSAVE <SrcReg>, <offset>
468 // Get the instruction's basic block.
469 MachineBasicBlock &MBB = *MI.getParent();
470 MachineFunction &MF = *MBB.getParent();
471 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
472 DebugLoc dl = MI.getDebugLoc();
474 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
475 unsigned Reg = MF.getRegInfo().createVirtualRegister(GPRC);
476 unsigned SrcReg = MI.getOperand(0).getReg();
478 BuildMI(MBB, II, dl, TII.get(PPC::MFVRSAVEv), Reg)
479 .addReg(SrcReg, getKillRegState(MI.getOperand(0).isKill()));
481 addFrameReference(BuildMI(MBB, II, dl, TII.get(PPC::STW))
482 .addReg(Reg, RegState::Kill),
485 // Discard the pseudo instruction.
489 void PPCRegisterInfo::lowerVRSAVERestore(MachineBasicBlock::iterator II,
490 unsigned FrameIndex) const {
491 // Get the instruction.
492 MachineInstr &MI = *II; // ; <DestReg> = RESTORE_VRSAVE <offset>
493 // Get the instruction's basic block.
494 MachineBasicBlock &MBB = *MI.getParent();
495 MachineFunction &MF = *MBB.getParent();
496 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
497 DebugLoc dl = MI.getDebugLoc();
499 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
500 unsigned Reg = MF.getRegInfo().createVirtualRegister(GPRC);
501 unsigned DestReg = MI.getOperand(0).getReg();
502 assert(MI.definesRegister(DestReg) &&
503 "RESTORE_VRSAVE does not define its destination");
505 addFrameReference(BuildMI(MBB, II, dl, TII.get(PPC::LWZ),
508 BuildMI(MBB, II, dl, TII.get(PPC::MTVRSAVEv), DestReg)
509 .addReg(Reg, RegState::Kill);
511 // Discard the pseudo instruction.
516 PPCRegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
517 unsigned Reg, int &FrameIdx) const {
519 // For the nonvolatile condition registers (CR2, CR3, CR4) in an SVR4
520 // ABI, return true to prevent allocating an additional frame slot.
521 // For 64-bit, the CR save area is at SP+8; the value of FrameIdx = 0
522 // is arbitrary and will be subsequently ignored. For 32-bit, we have
523 // previously created the stack slot if needed, so return its FrameIdx.
524 if (Subtarget.isSVR4ABI() && PPC::CR2 <= Reg && Reg <= PPC::CR4) {
525 if (Subtarget.isPPC64())
528 const PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
529 FrameIdx = FI->getCRSpillFrameIndex();
536 // Figure out if the offset in the instruction must be a multiple of 4.
537 // This is true for instructions like "STD".
538 static bool usesIXAddr(const MachineInstr &MI) {
539 unsigned OpC = MI.getOpcode();
552 // Return the OffsetOperandNo given the FIOperandNum (and the instruction).
553 static unsigned getOffsetONFromFION(const MachineInstr &MI,
554 unsigned FIOperandNum) {
555 // Take into account whether it's an add or mem instruction
556 unsigned OffsetOperandNo = (FIOperandNum == 2) ? 1 : 2;
557 if (MI.isInlineAsm())
558 OffsetOperandNo = FIOperandNum-1;
560 return OffsetOperandNo;
564 PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
565 int SPAdj, unsigned FIOperandNum,
566 RegScavenger *RS) const {
567 assert(SPAdj == 0 && "Unexpected");
569 // Get the instruction.
570 MachineInstr &MI = *II;
571 // Get the instruction's basic block.
572 MachineBasicBlock &MBB = *MI.getParent();
573 // Get the basic block's function.
574 MachineFunction &MF = *MBB.getParent();
575 // Get the instruction info.
576 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
577 // Get the frame info.
578 MachineFrameInfo *MFI = MF.getFrameInfo();
579 DebugLoc dl = MI.getDebugLoc();
581 unsigned OffsetOperandNo = getOffsetONFromFION(MI, FIOperandNum);
583 // Get the frame index.
584 int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
586 // Get the frame pointer save index. Users of this index are primarily
587 // DYNALLOC instructions.
588 PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
589 int FPSI = FI->getFramePointerSaveIndex();
590 // Get the instruction opcode.
591 unsigned OpC = MI.getOpcode();
593 // Special case for dynamic alloca.
594 if (FPSI && FrameIndex == FPSI &&
595 (OpC == PPC::DYNALLOC || OpC == PPC::DYNALLOC8)) {
596 lowerDynamicAlloc(II);
600 // Special case for pseudo-ops SPILL_CR and RESTORE_CR, etc.
601 if (OpC == PPC::SPILL_CR) {
602 lowerCRSpilling(II, FrameIndex);
604 } else if (OpC == PPC::RESTORE_CR) {
605 lowerCRRestore(II, FrameIndex);
607 } else if (OpC == PPC::SPILL_VRSAVE) {
608 lowerVRSAVESpilling(II, FrameIndex);
610 } else if (OpC == PPC::RESTORE_VRSAVE) {
611 lowerVRSAVERestore(II, FrameIndex);
615 // Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
616 MI.getOperand(FIOperandNum).ChangeToRegister(
617 FrameIndex < 0 ? getBaseRegister(MF) : getFrameRegister(MF), false);
619 // Figure out if the offset in the instruction is shifted right two bits.
620 bool isIXAddr = usesIXAddr(MI);
622 // If the instruction is not present in ImmToIdxMap, then it has no immediate
623 // form (and must be r+r).
624 bool noImmForm = !MI.isInlineAsm() && !ImmToIdxMap.count(OpC);
626 // Now add the frame object offset to the offset from r1.
627 int Offset = MFI->getObjectOffset(FrameIndex);
628 Offset += MI.getOperand(OffsetOperandNo).getImm();
630 // If we're not using a Frame Pointer that has been set to the value of the
631 // SP before having the stack size subtracted from it, then add the stack size
632 // to Offset to get the correct offset.
633 // Naked functions have stack size 0, although getStackSize may not reflect that
634 // because we didn't call all the pieces that compute it for naked functions.
635 if (!MF.getFunction()->getAttributes().
636 hasAttribute(AttributeSet::FunctionIndex, Attribute::Naked)) {
637 if (!(hasBasePointer(MF) && FrameIndex < 0))
638 Offset += MFI->getStackSize();
641 // If we can, encode the offset directly into the instruction. If this is a
642 // normal PPC "ri" instruction, any 16-bit value can be safely encoded. If
643 // this is a PPC64 "ix" instruction, only a 16-bit value with the low two bits
644 // clear can be encoded. This is extremely uncommon, because normally you
645 // only "std" to a stack slot that is at least 4-byte aligned, but it can
646 // happen in invalid code.
647 assert(OpC != PPC::DBG_VALUE &&
648 "This should be handle in a target independent way");
649 if (!noImmForm && isInt<16>(Offset) && (!isIXAddr || (Offset & 3) == 0)) {
650 MI.getOperand(OffsetOperandNo).ChangeToImmediate(Offset);
654 // The offset doesn't fit into a single register, scavenge one to build the
657 bool is64Bit = Subtarget.isPPC64();
658 const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
659 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
660 const TargetRegisterClass *RC = is64Bit ? G8RC : GPRC;
661 unsigned SRegHi = MF.getRegInfo().createVirtualRegister(RC),
662 SReg = MF.getRegInfo().createVirtualRegister(RC);
664 // Insert a set of rA with the full offset value before the ld, st, or add
665 BuildMI(MBB, II, dl, TII.get(is64Bit ? PPC::LIS8 : PPC::LIS), SRegHi)
666 .addImm(Offset >> 16);
667 BuildMI(MBB, II, dl, TII.get(is64Bit ? PPC::ORI8 : PPC::ORI), SReg)
668 .addReg(SRegHi, RegState::Kill)
671 // Convert into indexed form of the instruction:
673 // sth 0:rA, 1:imm 2:(rB) ==> sthx 0:rA, 2:rB, 1:r0
674 // addi 0:rA 1:rB, 2, imm ==> add 0:rA, 1:rB, 2:r0
675 unsigned OperandBase;
679 else if (OpC != TargetOpcode::INLINEASM) {
680 assert(ImmToIdxMap.count(OpC) &&
681 "No indexed form of load or store available!");
682 unsigned NewOpcode = ImmToIdxMap.find(OpC)->second;
683 MI.setDesc(TII.get(NewOpcode));
686 OperandBase = OffsetOperandNo;
689 unsigned StackReg = MI.getOperand(FIOperandNum).getReg();
690 MI.getOperand(OperandBase).ChangeToRegister(StackReg, false);
691 MI.getOperand(OperandBase + 1).ChangeToRegister(SReg, false, false, true);
694 unsigned PPCRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
695 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
697 if (!Subtarget.isPPC64())
698 return TFI->hasFP(MF) ? PPC::R31 : PPC::R1;
700 return TFI->hasFP(MF) ? PPC::X31 : PPC::X1;
703 unsigned PPCRegisterInfo::getBaseRegister(const MachineFunction &MF) const {
704 if (!hasBasePointer(MF))
705 return getFrameRegister(MF);
707 if (Subtarget.isPPC64())
710 if (Subtarget.isSVR4ABI() &&
711 MF.getTarget().getRelocationModel() == Reloc::PIC_)
717 bool PPCRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
718 if (!EnableBasePointer)
720 if (AlwaysBasePointer)
723 // If we need to realign the stack, then the stack pointer can no longer
724 // serve as an offset into the caller's stack space. As a result, we need a
726 return needsStackRealignment(MF);
729 bool PPCRegisterInfo::canRealignStack(const MachineFunction &MF) const {
730 if (MF.getFunction()->hasFnAttribute("no-realign-stack"))
736 bool PPCRegisterInfo::needsStackRealignment(const MachineFunction &MF) const {
737 const MachineFrameInfo *MFI = MF.getFrameInfo();
738 const Function *F = MF.getFunction();
739 unsigned StackAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
740 bool requiresRealignment =
741 ((MFI->getMaxAlignment() > StackAlign) ||
742 F->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
743 Attribute::StackAlignment));
745 return requiresRealignment && canRealignStack(MF);
748 /// Returns true if the instruction's frame index
749 /// reference would be better served by a base register other than FP
750 /// or SP. Used by LocalStackFrameAllocation to determine which frame index
751 /// references it should create new base registers for.
752 bool PPCRegisterInfo::
753 needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
754 assert(Offset < 0 && "Local offset must be negative");
756 unsigned FIOperandNum = 0;
757 while (!MI->getOperand(FIOperandNum).isFI()) {
759 assert(FIOperandNum < MI->getNumOperands() &&
760 "Instr doesn't have FrameIndex operand!");
763 unsigned OffsetOperandNo = getOffsetONFromFION(*MI, FIOperandNum);
764 Offset += MI->getOperand(OffsetOperandNo).getImm();
766 // It's the load/store FI references that cause issues, as it can be difficult
767 // to materialize the offset if it won't fit in the literal field. Estimate
768 // based on the size of the local frame and some conservative assumptions
769 // about the rest of the stack frame (note, this is pre-regalloc, so
770 // we don't know everything for certain yet) whether this offset is likely
771 // to be out of range of the immediate. Return true if so.
773 // We only generate virtual base registers for loads and stores that have
774 // an r+i form. Return false for everything else.
775 unsigned OpC = MI->getOpcode();
776 if (!ImmToIdxMap.count(OpC))
779 // Don't generate a new virtual base register just to add zero to it.
780 if ((OpC == PPC::ADDI || OpC == PPC::ADDI8) &&
781 MI->getOperand(2).getImm() == 0)
784 MachineBasicBlock &MBB = *MI->getParent();
785 MachineFunction &MF = *MBB.getParent();
787 const PPCFrameLowering *PPCFI =
788 static_cast<const PPCFrameLowering*>(MF.getTarget().getFrameLowering());
790 PPCFI->determineFrameLayout(MF, false, true);
792 // If we likely don't need a stack frame, then we probably don't need a
793 // virtual base register either.
797 // Estimate an offset from the stack pointer.
798 // The incoming offset is relating to the SP at the start of the function,
799 // but when we access the local it'll be relative to the SP after local
800 // allocation, so adjust our SP-relative offset by that allocation size.
803 // The frame pointer will point to the end of the stack, so estimate the
804 // offset as the difference between the object offset and the FP location.
805 return !isFrameOffsetLegal(MI, Offset);
808 /// Insert defining instruction(s) for BaseReg to
809 /// be a pointer to FrameIdx at the beginning of the basic block.
810 void PPCRegisterInfo::
811 materializeFrameBaseRegister(MachineBasicBlock *MBB,
812 unsigned BaseReg, int FrameIdx,
813 int64_t Offset) const {
814 unsigned ADDriOpc = Subtarget.isPPC64() ? PPC::ADDI8 : PPC::ADDI;
816 MachineBasicBlock::iterator Ins = MBB->begin();
817 DebugLoc DL; // Defaults to "unknown"
818 if (Ins != MBB->end())
819 DL = Ins->getDebugLoc();
821 const MachineFunction &MF = *MBB->getParent();
822 const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
823 const MCInstrDesc &MCID = TII.get(ADDriOpc);
824 MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
825 MRI.constrainRegClass(BaseReg, TII.getRegClass(MCID, 0, this, MF));
827 BuildMI(*MBB, Ins, DL, MCID, BaseReg)
828 .addFrameIndex(FrameIdx).addImm(Offset);
832 PPCRegisterInfo::resolveFrameIndex(MachineBasicBlock::iterator I,
833 unsigned BaseReg, int64_t Offset) const {
834 MachineInstr &MI = *I;
836 unsigned FIOperandNum = 0;
837 while (!MI.getOperand(FIOperandNum).isFI()) {
839 assert(FIOperandNum < MI.getNumOperands() &&
840 "Instr doesn't have FrameIndex operand!");
843 MI.getOperand(FIOperandNum).ChangeToRegister(BaseReg, false);
844 unsigned OffsetOperandNo = getOffsetONFromFION(MI, FIOperandNum);
845 Offset += MI.getOperand(OffsetOperandNo).getImm();
846 MI.getOperand(OffsetOperandNo).ChangeToImmediate(Offset);
849 bool PPCRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
850 int64_t Offset) const {
851 return MI->getOpcode() == PPC::DBG_VALUE || // DBG_VALUE is always Reg+Imm
852 (isInt<16>(Offset) && (!usesIXAddr(*MI) || (Offset & 3) == 0));