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"
51 PPCRegisterInfo::PPCRegisterInfo(const PPCSubtarget &ST,
52 const TargetInstrInfo &tii)
53 : PPCGenRegisterInfo(ST.isPPC64() ? PPC::LR8 : PPC::LR,
55 ST.isPPC64() ? 0 : 1),
56 Subtarget(ST), TII(tii) {
57 ImmToIdxMap[PPC::LD] = PPC::LDX; ImmToIdxMap[PPC::STD] = PPC::STDX;
58 ImmToIdxMap[PPC::LBZ] = PPC::LBZX; ImmToIdxMap[PPC::STB] = PPC::STBX;
59 ImmToIdxMap[PPC::LHZ] = PPC::LHZX; ImmToIdxMap[PPC::LHA] = PPC::LHAX;
60 ImmToIdxMap[PPC::LWZ] = PPC::LWZX; ImmToIdxMap[PPC::LWA] = PPC::LWAX;
61 ImmToIdxMap[PPC::LFS] = PPC::LFSX; ImmToIdxMap[PPC::LFD] = PPC::LFDX;
62 ImmToIdxMap[PPC::STH] = PPC::STHX; ImmToIdxMap[PPC::STW] = PPC::STWX;
63 ImmToIdxMap[PPC::STFS] = PPC::STFSX; ImmToIdxMap[PPC::STFD] = PPC::STFDX;
64 ImmToIdxMap[PPC::ADDI] = PPC::ADD4;
67 ImmToIdxMap[PPC::LHA8] = PPC::LHAX8; ImmToIdxMap[PPC::LBZ8] = PPC::LBZX8;
68 ImmToIdxMap[PPC::LHZ8] = PPC::LHZX8; ImmToIdxMap[PPC::LWZ8] = PPC::LWZX8;
69 ImmToIdxMap[PPC::STB8] = PPC::STBX8; ImmToIdxMap[PPC::STH8] = PPC::STHX8;
70 ImmToIdxMap[PPC::STW8] = PPC::STWX8; ImmToIdxMap[PPC::STDU] = PPC::STDUX;
71 ImmToIdxMap[PPC::ADDI8] = PPC::ADD8; ImmToIdxMap[PPC::STD_32] = PPC::STDX_32;
74 /// getPointerRegClass - Return the register class to use to hold pointers.
75 /// This is used for addressing modes.
76 const TargetRegisterClass *
77 PPCRegisterInfo::getPointerRegClass(const MachineFunction &MF, unsigned Kind)
80 if (Subtarget.isPPC64())
81 return &PPC::G8RC_NOX0RegClass;
82 return &PPC::GPRC_NOR0RegClass;
85 if (Subtarget.isPPC64())
86 return &PPC::G8RCRegClass;
87 return &PPC::GPRCRegClass;
91 PPCRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
92 if (Subtarget.isDarwinABI())
93 return Subtarget.isPPC64() ? CSR_Darwin64_SaveList :
94 CSR_Darwin32_SaveList;
96 return Subtarget.isPPC64() ? CSR_SVR464_SaveList : CSR_SVR432_SaveList;
100 PPCRegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
101 if (Subtarget.isDarwinABI())
102 return Subtarget.isPPC64() ? CSR_Darwin64_RegMask :
103 CSR_Darwin32_RegMask;
105 return Subtarget.isPPC64() ? CSR_SVR464_RegMask : CSR_SVR432_RegMask;
108 BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
109 BitVector Reserved(getNumRegs());
110 const PPCFrameLowering *PPCFI =
111 static_cast<const PPCFrameLowering*>(MF.getTarget().getFrameLowering());
113 // The ZERO register is not really a register, but the representation of r0
114 // when used in instructions that treat r0 as the constant 0.
115 Reserved.set(PPC::ZERO);
117 Reserved.set(PPC::R0);
118 Reserved.set(PPC::R1);
119 Reserved.set(PPC::LR);
120 Reserved.set(PPC::LR8);
121 Reserved.set(PPC::RM);
123 // The SVR4 ABI reserves r2 and r13
124 if (Subtarget.isSVR4ABI()) {
125 Reserved.set(PPC::R2); // System-reserved register
126 Reserved.set(PPC::R13); // Small Data Area pointer register
129 // On PPC64, r13 is the thread pointer. Never allocate this register.
130 if (Subtarget.isPPC64()) {
131 Reserved.set(PPC::R13);
133 Reserved.set(PPC::X0);
134 Reserved.set(PPC::X1);
135 Reserved.set(PPC::X13);
137 if (PPCFI->needsFP(MF))
138 Reserved.set(PPC::X31);
140 // The 64-bit SVR4 ABI reserves r2 for the TOC pointer.
141 if (Subtarget.isSVR4ABI()) {
142 Reserved.set(PPC::X2);
146 if (PPCFI->needsFP(MF))
147 Reserved.set(PPC::R31);
153 PPCRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
154 MachineFunction &MF) const {
155 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
156 const unsigned DefaultSafety = 1;
158 switch (RC->getID()) {
161 case PPC::G8RC_NOX0RegClassID:
162 case PPC::GPRC_NOR0RegClassID:
163 case PPC::G8RCRegClassID:
164 case PPC::GPRCRegClassID: {
165 unsigned FP = TFI->hasFP(MF) ? 1 : 0;
166 return 32 - FP - DefaultSafety;
168 case PPC::F8RCRegClassID:
169 case PPC::F4RCRegClassID:
170 case PPC::VRRCRegClassID:
171 return 32 - DefaultSafety;
172 case PPC::CRRCRegClassID:
173 return 8 - DefaultSafety;
177 //===----------------------------------------------------------------------===//
178 // Stack Frame Processing methods
179 //===----------------------------------------------------------------------===//
181 /// lowerDynamicAlloc - Generate the code for allocating an object in the
182 /// current frame. The sequence of code with be in the general form
184 /// addi R0, SP, \#frameSize ; get the address of the previous frame
185 /// stwxu R0, SP, Rnegsize ; add and update the SP with the negated size
186 /// addi Rnew, SP, \#maxCalFrameSize ; get the top of the allocation
188 void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II,
189 int SPAdj, RegScavenger *RS) const {
190 // Get the instruction.
191 MachineInstr &MI = *II;
192 // Get the instruction's basic block.
193 MachineBasicBlock &MBB = *MI.getParent();
194 // Get the basic block's function.
195 MachineFunction &MF = *MBB.getParent();
196 // Get the frame info.
197 MachineFrameInfo *MFI = MF.getFrameInfo();
198 // Determine whether 64-bit pointers are used.
199 bool LP64 = Subtarget.isPPC64();
200 DebugLoc dl = MI.getDebugLoc();
202 // Get the maximum call stack size.
203 unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
204 // Get the total frame size.
205 unsigned FrameSize = MFI->getStackSize();
207 // Get stack alignments.
208 unsigned TargetAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
209 unsigned MaxAlign = MFI->getMaxAlignment();
210 if (MaxAlign > TargetAlign)
211 report_fatal_error("Dynamic alloca with large aligns not supported");
213 // Determine the previous frame's address. If FrameSize can't be
214 // represented as 16 bits or we need special alignment, then we load the
215 // previous frame's address from 0(SP). Why not do an addis of the hi?
216 // Because R0 is our only safe tmp register and addi/addis treat R0 as zero.
217 // Constructing the constant and adding would take 3 instructions.
218 // Fortunately, a frame greater than 32K is rare.
219 const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
220 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
221 unsigned Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
223 if (MaxAlign < TargetAlign && isInt<16>(FrameSize)) {
224 BuildMI(MBB, II, dl, TII.get(PPC::ADDI), Reg)
228 BuildMI(MBB, II, dl, TII.get(PPC::LD), Reg)
232 BuildMI(MBB, II, dl, TII.get(PPC::LWZ), Reg)
237 // Grow the stack and update the stack pointer link, then determine the
238 // address of new allocated space.
240 BuildMI(MBB, II, dl, TII.get(PPC::STDUX), PPC::X1)
241 .addReg(Reg, RegState::Kill)
243 .addReg(MI.getOperand(1).getReg());
244 if (!MI.getOperand(1).isKill())
245 BuildMI(MBB, II, dl, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
247 .addImm(maxCallFrameSize);
249 // Implicitly kill the register.
250 BuildMI(MBB, II, dl, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
252 .addImm(maxCallFrameSize)
253 .addReg(MI.getOperand(1).getReg(), RegState::ImplicitKill);
255 BuildMI(MBB, II, dl, TII.get(PPC::STWUX), PPC::R1)
256 .addReg(Reg, RegState::Kill)
258 .addReg(MI.getOperand(1).getReg());
260 if (!MI.getOperand(1).isKill())
261 BuildMI(MBB, II, dl, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
263 .addImm(maxCallFrameSize);
265 // Implicitly kill the register.
266 BuildMI(MBB, II, dl, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
268 .addImm(maxCallFrameSize)
269 .addReg(MI.getOperand(1).getReg(), RegState::ImplicitKill);
272 // Discard the DYNALLOC instruction.
276 /// lowerCRSpilling - Generate the code for spilling a CR register. Instead of
277 /// reserving a whole register (R0), we scrounge for one here. This generates
280 /// mfcr rA ; Move the conditional register into GPR rA.
281 /// rlwinm rA, rA, SB, 0, 31 ; Shift the bits left so they are in CR0's slot.
282 /// stw rA, FI ; Store rA to the frame.
284 void PPCRegisterInfo::lowerCRSpilling(MachineBasicBlock::iterator II,
285 unsigned FrameIndex, int SPAdj,
286 RegScavenger *RS) const {
287 // Get the instruction.
288 MachineInstr &MI = *II; // ; SPILL_CR <SrcReg>, <offset>
289 // Get the instruction's basic block.
290 MachineBasicBlock &MBB = *MI.getParent();
291 DebugLoc dl = MI.getDebugLoc();
293 // FIXME: Once LLVM supports creating virtual registers here, or the register
294 // scavenger can return multiple registers, stop using reserved registers
299 bool LP64 = Subtarget.isPPC64();
300 unsigned Reg = LP64 ? PPC::X0 : PPC::R0;
301 unsigned SrcReg = MI.getOperand(0).getReg();
303 // We need to store the CR in the low 4-bits of the saved value. First, issue
304 // an MFCRpsued to save all of the CRBits and, if needed, kill the SrcReg.
305 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::MFCR8pseud : PPC::MFCRpseud), Reg)
306 .addReg(SrcReg, getKillRegState(MI.getOperand(0).isKill()));
308 // If the saved register wasn't CR0, shift the bits left so that they are in
310 if (SrcReg != PPC::CR0)
311 // rlwinm rA, rA, ShiftBits, 0, 31.
312 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::RLWINM8 : PPC::RLWINM), Reg)
313 .addReg(Reg, RegState::Kill)
314 .addImm(getPPCRegisterNumbering(SrcReg) * 4)
318 addFrameReference(BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::STW8 : PPC::STW))
319 .addReg(Reg, getKillRegState(MI.getOperand(1).getImm())),
322 // Discard the pseudo instruction.
326 void PPCRegisterInfo::lowerCRRestore(MachineBasicBlock::iterator II,
327 unsigned FrameIndex, int SPAdj,
328 RegScavenger *RS) const {
329 // Get the instruction.
330 MachineInstr &MI = *II; // ; <DestReg> = RESTORE_CR <offset>
331 // Get the instruction's basic block.
332 MachineBasicBlock &MBB = *MI.getParent();
333 DebugLoc dl = MI.getDebugLoc();
335 // FIXME: Once LLVM supports creating virtual registers here, or the register
336 // scavenger can return multiple registers, stop using reserved registers
341 bool LP64 = Subtarget.isPPC64();
342 unsigned Reg = LP64 ? PPC::X0 : PPC::R0;
343 unsigned DestReg = MI.getOperand(0).getReg();
344 assert(MI.definesRegister(DestReg) &&
345 "RESTORE_CR does not define its destination");
347 addFrameReference(BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::LWZ8 : PPC::LWZ),
350 // If the reloaded register isn't CR0, shift the bits right so that they are
351 // in the right CR's slot.
352 if (DestReg != PPC::CR0) {
353 unsigned ShiftBits = getPPCRegisterNumbering(DestReg)*4;
354 // rlwinm r11, r11, 32-ShiftBits, 0, 31.
355 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::RLWINM8 : PPC::RLWINM), Reg)
356 .addReg(Reg).addImm(32-ShiftBits).addImm(0)
360 BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::MTCRF8 : PPC::MTCRF), DestReg)
363 // Discard the pseudo instruction.
368 PPCRegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
369 unsigned Reg, int &FrameIdx) const {
371 // For the nonvolatile condition registers (CR2, CR3, CR4) in an SVR4
372 // ABI, return true to prevent allocating an additional frame slot.
373 // For 64-bit, the CR save area is at SP+8; the value of FrameIdx = 0
374 // is arbitrary and will be subsequently ignored. For 32-bit, we have
375 // previously created the stack slot if needed, so return its FrameIdx.
376 if (Subtarget.isSVR4ABI() && PPC::CR2 <= Reg && Reg <= PPC::CR4) {
377 if (Subtarget.isPPC64())
380 const PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
381 FrameIdx = FI->getCRSpillFrameIndex();
389 PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
390 int SPAdj, unsigned FIOperandNum,
391 RegScavenger *RS) const {
392 assert(SPAdj == 0 && "Unexpected");
394 // Get the instruction.
395 MachineInstr &MI = *II;
396 // Get the instruction's basic block.
397 MachineBasicBlock &MBB = *MI.getParent();
398 // Get the basic block's function.
399 MachineFunction &MF = *MBB.getParent();
400 // Get the frame info.
401 MachineFrameInfo *MFI = MF.getFrameInfo();
402 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
403 DebugLoc dl = MI.getDebugLoc();
405 // Take into account whether it's an add or mem instruction
406 unsigned OffsetOperandNo = (FIOperandNum == 2) ? 1 : 2;
407 if (MI.isInlineAsm())
408 OffsetOperandNo = FIOperandNum-1;
410 // Get the frame index.
411 int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
413 // Get the frame pointer save index. Users of this index are primarily
414 // DYNALLOC instructions.
415 PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
416 int FPSI = FI->getFramePointerSaveIndex();
417 // Get the instruction opcode.
418 unsigned OpC = MI.getOpcode();
420 // Special case for dynamic alloca.
421 if (FPSI && FrameIndex == FPSI &&
422 (OpC == PPC::DYNALLOC || OpC == PPC::DYNALLOC8)) {
423 lowerDynamicAlloc(II, SPAdj, RS);
427 // Special case for pseudo-ops SPILL_CR and RESTORE_CR.
428 if (OpC == PPC::SPILL_CR) {
429 lowerCRSpilling(II, FrameIndex, SPAdj, RS);
431 } else if (OpC == PPC::RESTORE_CR) {
432 lowerCRRestore(II, FrameIndex, SPAdj, RS);
436 // Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
438 bool is64Bit = Subtarget.isPPC64();
439 MI.getOperand(FIOperandNum).ChangeToRegister(TFI->hasFP(MF) ?
440 (is64Bit ? PPC::X31 : PPC::R31) :
441 (is64Bit ? PPC::X1 : PPC::R1),
444 // Figure out if the offset in the instruction is shifted right two bits. This
445 // is true for instructions like "STD", which the machine implicitly adds two
447 bool isIXAddr = false;
457 bool noImmForm = false;
475 // Now add the frame object offset to the offset from r1.
476 int Offset = MFI->getObjectOffset(FrameIndex);
478 Offset += MI.getOperand(OffsetOperandNo).getImm();
480 Offset += MI.getOperand(OffsetOperandNo).getImm() << 2;
482 // If we're not using a Frame Pointer that has been set to the value of the
483 // SP before having the stack size subtracted from it, then add the stack size
484 // to Offset to get the correct offset.
485 // Naked functions have stack size 0, although getStackSize may not reflect that
486 // because we didn't call all the pieces that compute it for naked functions.
487 if (!MF.getFunction()->getAttributes().
488 hasAttribute(AttributeSet::FunctionIndex, Attribute::Naked))
489 Offset += MFI->getStackSize();
491 // If we can, encode the offset directly into the instruction. If this is a
492 // normal PPC "ri" instruction, any 16-bit value can be safely encoded. If
493 // this is a PPC64 "ix" instruction, only a 16-bit value with the low two bits
494 // clear can be encoded. This is extremely uncommon, because normally you
495 // only "std" to a stack slot that is at least 4-byte aligned, but it can
496 // happen in invalid code.
497 if (OpC == PPC::DBG_VALUE || // DBG_VALUE is always Reg+Imm
499 isInt<16>(Offset) && (!isIXAddr || (Offset & 3) == 0))) {
501 Offset >>= 2; // The actual encoded value has the low two bits zero.
502 MI.getOperand(OffsetOperandNo).ChangeToImmediate(Offset);
506 // The offset doesn't fit into a single register, scavenge one to build the
509 const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
510 const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
511 unsigned SReg = MF.getRegInfo().createVirtualRegister(is64Bit ? G8RC : GPRC);
513 // Insert a set of rA with the full offset value before the ld, st, or add
514 BuildMI(MBB, II, dl, TII.get(is64Bit ? PPC::LIS8 : PPC::LIS), SReg)
515 .addImm(Offset >> 16);
516 BuildMI(MBB, II, dl, TII.get(is64Bit ? PPC::ORI8 : PPC::ORI), SReg)
517 .addReg(SReg, RegState::Kill)
520 // Convert into indexed form of the instruction:
522 // sth 0:rA, 1:imm 2:(rB) ==> sthx 0:rA, 2:rB, 1:r0
523 // addi 0:rA 1:rB, 2, imm ==> add 0:rA, 1:rB, 2:r0
524 unsigned OperandBase;
528 else if (OpC != TargetOpcode::INLINEASM) {
529 assert(ImmToIdxMap.count(OpC) &&
530 "No indexed form of load or store available!");
531 unsigned NewOpcode = ImmToIdxMap.find(OpC)->second;
532 MI.setDesc(TII.get(NewOpcode));
535 OperandBase = OffsetOperandNo;
538 unsigned StackReg = MI.getOperand(FIOperandNum).getReg();
539 MI.getOperand(OperandBase).ChangeToRegister(StackReg, false);
540 MI.getOperand(OperandBase + 1).ChangeToRegister(SReg, false, false, true);
543 unsigned PPCRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
544 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
546 if (!Subtarget.isPPC64())
547 return TFI->hasFP(MF) ? PPC::R31 : PPC::R1;
549 return TFI->hasFP(MF) ? PPC::X31 : PPC::X1;
552 unsigned PPCRegisterInfo::getEHExceptionRegister() const {
553 return !Subtarget.isPPC64() ? PPC::R3 : PPC::X3;
556 unsigned PPCRegisterInfo::getEHHandlerRegister() const {
557 return !Subtarget.isPPC64() ? PPC::R4 : PPC::X4;