1 //===-- X86RegisterInfo.cpp - X86 Register Information --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the X86 implementation of the TargetRegisterInfo class.
11 // This file is responsible for the frame pointer elimination optimization
12 // on X86.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "X86RegisterInfo.h"
17 #include "X86FrameLowering.h"
18 #include "X86InstrBuilder.h"
19 #include "X86MachineFunctionInfo.h"
20 #include "X86Subtarget.h"
21 #include "X86TargetMachine.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/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachineInstrBuilder.h"
28 #include "llvm/CodeGen/MachineModuleInfo.h"
29 #include "llvm/CodeGen/MachineRegisterInfo.h"
30 #include "llvm/CodeGen/MachineValueType.h"
31 #include "llvm/IR/Constants.h"
32 #include "llvm/IR/Function.h"
33 #include "llvm/IR/Type.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/ErrorHandling.h"
37 #include "llvm/Target/TargetFrameLowering.h"
38 #include "llvm/Target/TargetInstrInfo.h"
39 #include "llvm/Target/TargetMachine.h"
40 #include "llvm/Target/TargetOptions.h"
41 
42 using namespace llvm;
43 
44 #define GET_REGINFO_TARGET_DESC
45 #include "X86GenRegisterInfo.inc"
46 
47 static cl::opt<bool>
48 EnableBasePointer("x86-use-base-pointer", cl::Hidden, cl::init(true),
49           cl::desc("Enable use of a base pointer for complex stack frames"));
50 
X86RegisterInfo(const Triple & TT)51 X86RegisterInfo::X86RegisterInfo(const Triple &TT)
52     : X86GenRegisterInfo((TT.isArch64Bit() ? X86::RIP : X86::EIP),
53                          X86_MC::getDwarfRegFlavour(TT, false),
54                          X86_MC::getDwarfRegFlavour(TT, true),
55                          (TT.isArch64Bit() ? X86::RIP : X86::EIP)) {
56   X86_MC::InitLLVM2SEHRegisterMapping(this);
57 
58   // Cache some information.
59   Is64Bit = TT.isArch64Bit();
60   IsWin64 = Is64Bit && TT.isOSWindows();
61 
62   // Use a callee-saved register as the base pointer.  These registers must
63   // not conflict with any ABI requirements.  For example, in 32-bit mode PIC
64   // requires GOT in the EBX register before function calls via PLT GOT pointer.
65   if (Is64Bit) {
66     SlotSize = 8;
67     // This matches the simplified 32-bit pointer code in the data layout
68     // computation.
69     // FIXME: Should use the data layout?
70     bool Use64BitReg = TT.getEnvironment() != Triple::GNUX32;
71     StackPtr = Use64BitReg ? X86::RSP : X86::ESP;
72     FramePtr = Use64BitReg ? X86::RBP : X86::EBP;
73     BasePtr = Use64BitReg ? X86::RBX : X86::EBX;
74   } else {
75     SlotSize = 4;
76     StackPtr = X86::ESP;
77     FramePtr = X86::EBP;
78     BasePtr = X86::ESI;
79   }
80 }
81 
82 bool
trackLivenessAfterRegAlloc(const MachineFunction & MF) const83 X86RegisterInfo::trackLivenessAfterRegAlloc(const MachineFunction &MF) const {
84   // ExeDepsFixer and PostRAScheduler require liveness.
85   return true;
86 }
87 
88 int
getSEHRegNum(unsigned i) const89 X86RegisterInfo::getSEHRegNum(unsigned i) const {
90   return getEncodingValue(i);
91 }
92 
93 const TargetRegisterClass *
getSubClassWithSubReg(const TargetRegisterClass * RC,unsigned Idx) const94 X86RegisterInfo::getSubClassWithSubReg(const TargetRegisterClass *RC,
95                                        unsigned Idx) const {
96   // The sub_8bit sub-register index is more constrained in 32-bit mode.
97   // It behaves just like the sub_8bit_hi index.
98   if (!Is64Bit && Idx == X86::sub_8bit)
99     Idx = X86::sub_8bit_hi;
100 
101   // Forward to TableGen's default version.
102   return X86GenRegisterInfo::getSubClassWithSubReg(RC, Idx);
103 }
104 
105 const TargetRegisterClass *
getMatchingSuperRegClass(const TargetRegisterClass * A,const TargetRegisterClass * B,unsigned SubIdx) const106 X86RegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
107                                           const TargetRegisterClass *B,
108                                           unsigned SubIdx) const {
109   // The sub_8bit sub-register index is more constrained in 32-bit mode.
110   if (!Is64Bit && SubIdx == X86::sub_8bit) {
111     A = X86GenRegisterInfo::getSubClassWithSubReg(A, X86::sub_8bit_hi);
112     if (!A)
113       return nullptr;
114   }
115   return X86GenRegisterInfo::getMatchingSuperRegClass(A, B, SubIdx);
116 }
117 
118 const TargetRegisterClass *
getLargestLegalSuperClass(const TargetRegisterClass * RC,const MachineFunction & MF) const119 X86RegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC,
120                                            const MachineFunction &MF) const {
121   // Don't allow super-classes of GR8_NOREX.  This class is only used after
122   // extracting sub_8bit_hi sub-registers.  The H sub-registers cannot be copied
123   // to the full GR8 register class in 64-bit mode, so we cannot allow the
124   // reigster class inflation.
125   //
126   // The GR8_NOREX class is always used in a way that won't be constrained to a
127   // sub-class, so sub-classes like GR8_ABCD_L are allowed to expand to the
128   // full GR8 class.
129   if (RC == &X86::GR8_NOREXRegClass)
130     return RC;
131 
132   const TargetRegisterClass *Super = RC;
133   TargetRegisterClass::sc_iterator I = RC->getSuperClasses();
134   do {
135     switch (Super->getID()) {
136     case X86::GR8RegClassID:
137     case X86::GR16RegClassID:
138     case X86::GR32RegClassID:
139     case X86::GR64RegClassID:
140     case X86::FR32RegClassID:
141     case X86::FR64RegClassID:
142     case X86::RFP32RegClassID:
143     case X86::RFP64RegClassID:
144     case X86::RFP80RegClassID:
145     case X86::VR128RegClassID:
146     case X86::VR256RegClassID:
147       // Don't return a super-class that would shrink the spill size.
148       // That can happen with the vector and float classes.
149       if (Super->getSize() == RC->getSize())
150         return Super;
151     }
152     Super = *I++;
153   } while (Super);
154   return RC;
155 }
156 
157 const TargetRegisterClass *
getPointerRegClass(const MachineFunction & MF,unsigned Kind) const158 X86RegisterInfo::getPointerRegClass(const MachineFunction &MF,
159                                     unsigned Kind) const {
160   const X86Subtarget &Subtarget = MF.getSubtarget<X86Subtarget>();
161   switch (Kind) {
162   default: llvm_unreachable("Unexpected Kind in getPointerRegClass!");
163   case 0: // Normal GPRs.
164     if (Subtarget.isTarget64BitLP64())
165       return &X86::GR64RegClass;
166     return &X86::GR32RegClass;
167   case 1: // Normal GPRs except the stack pointer (for encoding reasons).
168     if (Subtarget.isTarget64BitLP64())
169       return &X86::GR64_NOSPRegClass;
170     return &X86::GR32_NOSPRegClass;
171   case 2: // NOREX GPRs.
172     if (Subtarget.isTarget64BitLP64())
173       return &X86::GR64_NOREXRegClass;
174     return &X86::GR32_NOREXRegClass;
175   case 3: // NOREX GPRs except the stack pointer (for encoding reasons).
176     if (Subtarget.isTarget64BitLP64())
177       return &X86::GR64_NOREX_NOSPRegClass;
178     return &X86::GR32_NOREX_NOSPRegClass;
179   case 4: // Available for tailcall (not callee-saved GPRs).
180     return getGPRsForTailCall(MF);
181   }
182 }
183 
184 const TargetRegisterClass *
getGPRsForTailCall(const MachineFunction & MF) const185 X86RegisterInfo::getGPRsForTailCall(const MachineFunction &MF) const {
186   const Function *F = MF.getFunction();
187   if (IsWin64 || (F && F->getCallingConv() == CallingConv::X86_64_Win64))
188     return &X86::GR64_TCW64RegClass;
189   else if (Is64Bit)
190     return &X86::GR64_TCRegClass;
191 
192   bool hasHipeCC = (F ? F->getCallingConv() == CallingConv::HiPE : false);
193   if (hasHipeCC)
194     return &X86::GR32RegClass;
195   return &X86::GR32_TCRegClass;
196 }
197 
198 const TargetRegisterClass *
getCrossCopyRegClass(const TargetRegisterClass * RC) const199 X86RegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
200   if (RC == &X86::CCRRegClass) {
201     if (Is64Bit)
202       return &X86::GR64RegClass;
203     else
204       return &X86::GR32RegClass;
205   }
206   return RC;
207 }
208 
209 unsigned
getRegPressureLimit(const TargetRegisterClass * RC,MachineFunction & MF) const210 X86RegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
211                                      MachineFunction &MF) const {
212   const X86FrameLowering *TFI = getFrameLowering(MF);
213 
214   unsigned FPDiff = TFI->hasFP(MF) ? 1 : 0;
215   switch (RC->getID()) {
216   default:
217     return 0;
218   case X86::GR32RegClassID:
219     return 4 - FPDiff;
220   case X86::GR64RegClassID:
221     return 12 - FPDiff;
222   case X86::VR128RegClassID:
223     return Is64Bit ? 10 : 4;
224   case X86::VR64RegClassID:
225     return 4;
226   }
227 }
228 
229 const MCPhysReg *
getCalleeSavedRegs(const MachineFunction * MF) const230 X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
231   const X86Subtarget &Subtarget = MF->getSubtarget<X86Subtarget>();
232   bool HasSSE = Subtarget.hasSSE1();
233   bool HasAVX = Subtarget.hasAVX();
234   bool HasAVX512 = Subtarget.hasAVX512();
235   bool CallsEHReturn = MF->getMMI().callsEHReturn();
236 
237   assert(MF && "MachineFunction required");
238   switch (MF->getFunction()->getCallingConv()) {
239   case CallingConv::GHC:
240   case CallingConv::HiPE:
241     return CSR_NoRegs_SaveList;
242   case CallingConv::AnyReg:
243     if (HasAVX)
244       return CSR_64_AllRegs_AVX_SaveList;
245     return CSR_64_AllRegs_SaveList;
246   case CallingConv::PreserveMost:
247     return CSR_64_RT_MostRegs_SaveList;
248   case CallingConv::PreserveAll:
249     if (HasAVX)
250       return CSR_64_RT_AllRegs_AVX_SaveList;
251     return CSR_64_RT_AllRegs_SaveList;
252   case CallingConv::CXX_FAST_TLS:
253     if (Is64Bit)
254       return CSR_64_TLS_Darwin_SaveList;
255     break;
256   case CallingConv::Intel_OCL_BI: {
257     if (HasAVX512 && IsWin64)
258       return CSR_Win64_Intel_OCL_BI_AVX512_SaveList;
259     if (HasAVX512 && Is64Bit)
260       return CSR_64_Intel_OCL_BI_AVX512_SaveList;
261     if (HasAVX && IsWin64)
262       return CSR_Win64_Intel_OCL_BI_AVX_SaveList;
263     if (HasAVX && Is64Bit)
264       return CSR_64_Intel_OCL_BI_AVX_SaveList;
265     if (!HasAVX && !IsWin64 && Is64Bit)
266       return CSR_64_Intel_OCL_BI_SaveList;
267     break;
268   }
269   case CallingConv::HHVM:
270     return CSR_64_HHVM_SaveList;
271   case CallingConv::Cold:
272     if (Is64Bit)
273       return CSR_64_MostRegs_SaveList;
274     break;
275   case CallingConv::X86_64_Win64:
276     return CSR_Win64_SaveList;
277   case CallingConv::X86_64_SysV:
278     if (CallsEHReturn)
279       return CSR_64EHRet_SaveList;
280     return CSR_64_SaveList;
281   case CallingConv::X86_INTR:
282     if (Is64Bit) {
283       if (HasAVX)
284         return CSR_64_AllRegs_AVX_SaveList;
285       else
286         return CSR_64_AllRegs_SaveList;
287     } else {
288       if (HasSSE)
289         return CSR_32_AllRegs_SSE_SaveList;
290       else
291         return CSR_32_AllRegs_SaveList;
292     }
293   default:
294     break;
295   }
296 
297   if (Is64Bit) {
298     if (IsWin64)
299       return CSR_Win64_SaveList;
300     if (CallsEHReturn)
301       return CSR_64EHRet_SaveList;
302     return CSR_64_SaveList;
303   }
304   if (CallsEHReturn)
305     return CSR_32EHRet_SaveList;
306   return CSR_32_SaveList;
307 }
308 
309 const uint32_t *
getCallPreservedMask(const MachineFunction & MF,CallingConv::ID CC) const310 X86RegisterInfo::getCallPreservedMask(const MachineFunction &MF,
311                                       CallingConv::ID CC) const {
312   const X86Subtarget &Subtarget = MF.getSubtarget<X86Subtarget>();
313   bool HasSSE = Subtarget.hasSSE1();
314   bool HasAVX = Subtarget.hasAVX();
315   bool HasAVX512 = Subtarget.hasAVX512();
316 
317   switch (CC) {
318   case CallingConv::GHC:
319   case CallingConv::HiPE:
320     return CSR_NoRegs_RegMask;
321   case CallingConv::AnyReg:
322     if (HasAVX)
323       return CSR_64_AllRegs_AVX_RegMask;
324     return CSR_64_AllRegs_RegMask;
325   case CallingConv::PreserveMost:
326     return CSR_64_RT_MostRegs_RegMask;
327   case CallingConv::PreserveAll:
328     if (HasAVX)
329       return CSR_64_RT_AllRegs_AVX_RegMask;
330     return CSR_64_RT_AllRegs_RegMask;
331   case CallingConv::CXX_FAST_TLS:
332     if (Is64Bit)
333       return CSR_64_TLS_Darwin_RegMask;
334     break;
335   case CallingConv::Intel_OCL_BI: {
336     if (HasAVX512 && IsWin64)
337       return CSR_Win64_Intel_OCL_BI_AVX512_RegMask;
338     if (HasAVX512 && Is64Bit)
339       return CSR_64_Intel_OCL_BI_AVX512_RegMask;
340     if (HasAVX && IsWin64)
341       return CSR_Win64_Intel_OCL_BI_AVX_RegMask;
342     if (HasAVX && Is64Bit)
343       return CSR_64_Intel_OCL_BI_AVX_RegMask;
344     if (!HasAVX && !IsWin64 && Is64Bit)
345       return CSR_64_Intel_OCL_BI_RegMask;
346     break;
347   }
348   case CallingConv::HHVM:
349     return CSR_64_HHVM_RegMask;
350   case CallingConv::Cold:
351     if (Is64Bit)
352       return CSR_64_MostRegs_RegMask;
353     break;
354   case CallingConv::X86_64_Win64:
355     return CSR_Win64_RegMask;
356   case CallingConv::X86_64_SysV:
357     return CSR_64_RegMask;
358   case CallingConv::X86_INTR:
359     if (Is64Bit) {
360       if (HasAVX)
361         return CSR_64_AllRegs_AVX_RegMask;
362       else
363         return CSR_64_AllRegs_RegMask;
364     } else {
365       if (HasSSE)
366         return CSR_32_AllRegs_SSE_RegMask;
367       else
368         return CSR_32_AllRegs_RegMask;
369     }
370     default:
371       break;
372   }
373 
374   // Unlike getCalleeSavedRegs(), we don't have MMI so we can't check
375   // callsEHReturn().
376   if (Is64Bit) {
377     if (IsWin64)
378       return CSR_Win64_RegMask;
379     return CSR_64_RegMask;
380   }
381   return CSR_32_RegMask;
382 }
383 
384 const uint32_t*
getNoPreservedMask() const385 X86RegisterInfo::getNoPreservedMask() const {
386   return CSR_NoRegs_RegMask;
387 }
388 
getDarwinTLSCallPreservedMask() const389 const uint32_t *X86RegisterInfo::getDarwinTLSCallPreservedMask() const {
390   return CSR_64_TLS_Darwin_RegMask;
391 }
392 
getReservedRegs(const MachineFunction & MF) const393 BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
394   BitVector Reserved(getNumRegs());
395   const X86FrameLowering *TFI = getFrameLowering(MF);
396 
397   // Set the stack-pointer register and its aliases as reserved.
398   for (MCSubRegIterator I(X86::RSP, this, /*IncludeSelf=*/true); I.isValid();
399        ++I)
400     Reserved.set(*I);
401 
402   // Set the instruction pointer register and its aliases as reserved.
403   for (MCSubRegIterator I(X86::RIP, this, /*IncludeSelf=*/true); I.isValid();
404        ++I)
405     Reserved.set(*I);
406 
407   // Set the frame-pointer register and its aliases as reserved if needed.
408   if (TFI->hasFP(MF)) {
409     for (MCSubRegIterator I(X86::RBP, this, /*IncludeSelf=*/true); I.isValid();
410          ++I)
411       Reserved.set(*I);
412   }
413 
414   // Set the base-pointer register and its aliases as reserved if needed.
415   if (hasBasePointer(MF)) {
416     CallingConv::ID CC = MF.getFunction()->getCallingConv();
417     const uint32_t *RegMask = getCallPreservedMask(MF, CC);
418     if (MachineOperand::clobbersPhysReg(RegMask, getBaseRegister()))
419       report_fatal_error(
420         "Stack realignment in presence of dynamic allocas is not supported with"
421         "this calling convention.");
422 
423     unsigned BasePtr = getX86SubSuperRegister(getBaseRegister(), MVT::i64,
424                                               false);
425     for (MCSubRegIterator I(BasePtr, this, /*IncludeSelf=*/true);
426          I.isValid(); ++I)
427       Reserved.set(*I);
428   }
429 
430   // Mark the segment registers as reserved.
431   Reserved.set(X86::CS);
432   Reserved.set(X86::SS);
433   Reserved.set(X86::DS);
434   Reserved.set(X86::ES);
435   Reserved.set(X86::FS);
436   Reserved.set(X86::GS);
437 
438   // Mark the floating point stack registers as reserved.
439   for (unsigned n = 0; n != 8; ++n)
440     Reserved.set(X86::ST0 + n);
441 
442   // Reserve the registers that only exist in 64-bit mode.
443   if (!Is64Bit) {
444     // These 8-bit registers are part of the x86-64 extension even though their
445     // super-registers are old 32-bits.
446     Reserved.set(X86::SIL);
447     Reserved.set(X86::DIL);
448     Reserved.set(X86::BPL);
449     Reserved.set(X86::SPL);
450 
451     for (unsigned n = 0; n != 8; ++n) {
452       // R8, R9, ...
453       for (MCRegAliasIterator AI(X86::R8 + n, this, true); AI.isValid(); ++AI)
454         Reserved.set(*AI);
455 
456       // XMM8, XMM9, ...
457       for (MCRegAliasIterator AI(X86::XMM8 + n, this, true); AI.isValid(); ++AI)
458         Reserved.set(*AI);
459     }
460   }
461   if (!Is64Bit || !MF.getSubtarget<X86Subtarget>().hasAVX512()) {
462     for (unsigned n = 16; n != 32; ++n) {
463       for (MCRegAliasIterator AI(X86::XMM0 + n, this, true); AI.isValid(); ++AI)
464         Reserved.set(*AI);
465     }
466   }
467 
468   return Reserved;
469 }
470 
adjustStackMapLiveOutMask(uint32_t * Mask) const471 void X86RegisterInfo::adjustStackMapLiveOutMask(uint32_t *Mask) const {
472   // Check if the EFLAGS register is marked as live-out. This shouldn't happen,
473   // because the calling convention defines the EFLAGS register as NOT
474   // preserved.
475   //
476   // Unfortunatelly the EFLAGS show up as live-out after branch folding. Adding
477   // an assert to track this and clear the register afterwards to avoid
478   // unnecessary crashes during release builds.
479   assert(!(Mask[X86::EFLAGS / 32] & (1U << (X86::EFLAGS % 32))) &&
480          "EFLAGS are not live-out from a patchpoint.");
481 
482   // Also clean other registers that don't need preserving (IP).
483   for (auto Reg : {X86::EFLAGS, X86::RIP, X86::EIP, X86::IP})
484     Mask[Reg / 32] &= ~(1U << (Reg % 32));
485 }
486 
487 //===----------------------------------------------------------------------===//
488 // Stack Frame Processing methods
489 //===----------------------------------------------------------------------===//
490 
CantUseSP(const MachineFrameInfo * MFI)491 static bool CantUseSP(const MachineFrameInfo *MFI) {
492   return MFI->hasVarSizedObjects() || MFI->hasOpaqueSPAdjustment();
493 }
494 
hasBasePointer(const MachineFunction & MF) const495 bool X86RegisterInfo::hasBasePointer(const MachineFunction &MF) const {
496    const MachineFrameInfo *MFI = MF.getFrameInfo();
497 
498    if (!EnableBasePointer)
499      return false;
500 
501    // When we need stack realignment, we can't address the stack from the frame
502    // pointer.  When we have dynamic allocas or stack-adjusting inline asm, we
503    // can't address variables from the stack pointer.  MS inline asm can
504    // reference locals while also adjusting the stack pointer.  When we can't
505    // use both the SP and the FP, we need a separate base pointer register.
506    bool CantUseFP = needsStackRealignment(MF);
507    return CantUseFP && CantUseSP(MFI);
508 }
509 
canRealignStack(const MachineFunction & MF) const510 bool X86RegisterInfo::canRealignStack(const MachineFunction &MF) const {
511   if (!TargetRegisterInfo::canRealignStack(MF))
512     return false;
513 
514   const MachineFrameInfo *MFI = MF.getFrameInfo();
515   const MachineRegisterInfo *MRI = &MF.getRegInfo();
516 
517   // Stack realignment requires a frame pointer.  If we already started
518   // register allocation with frame pointer elimination, it is too late now.
519   if (!MRI->canReserveReg(FramePtr))
520     return false;
521 
522   // If a base pointer is necessary.  Check that it isn't too late to reserve
523   // it.
524   if (CantUseSP(MFI))
525     return MRI->canReserveReg(BasePtr);
526   return true;
527 }
528 
hasReservedSpillSlot(const MachineFunction & MF,unsigned Reg,int & FrameIdx) const529 bool X86RegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
530                                            unsigned Reg, int &FrameIdx) const {
531   // Since X86 defines assignCalleeSavedSpillSlots which always return true
532   // this function neither used nor tested.
533   llvm_unreachable("Unused function on X86. Otherwise need a test case.");
534 }
535 
536 void
eliminateFrameIndex(MachineBasicBlock::iterator II,int SPAdj,unsigned FIOperandNum,RegScavenger * RS) const537 X86RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
538                                      int SPAdj, unsigned FIOperandNum,
539                                      RegScavenger *RS) const {
540   MachineInstr &MI = *II;
541   MachineFunction &MF = *MI.getParent()->getParent();
542   const X86FrameLowering *TFI = getFrameLowering(MF);
543   int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
544   unsigned BasePtr;
545 
546   unsigned Opc = MI.getOpcode();
547   bool AfterFPPop = Opc == X86::TAILJMPm64 || Opc == X86::TAILJMPm ||
548                     Opc == X86::TCRETURNmi || Opc == X86::TCRETURNmi64;
549 
550   if (hasBasePointer(MF))
551     BasePtr = (FrameIndex < 0 ? FramePtr : getBaseRegister());
552   else if (needsStackRealignment(MF))
553     BasePtr = (FrameIndex < 0 ? FramePtr : StackPtr);
554   else if (AfterFPPop)
555     BasePtr = StackPtr;
556   else
557     BasePtr = (TFI->hasFP(MF) ? FramePtr : StackPtr);
558 
559   // LOCAL_ESCAPE uses a single offset, with no register. It only works in the
560   // simple FP case, and doesn't work with stack realignment. On 32-bit, the
561   // offset is from the traditional base pointer location.  On 64-bit, the
562   // offset is from the SP at the end of the prologue, not the FP location. This
563   // matches the behavior of llvm.frameaddress.
564   unsigned IgnoredFrameReg;
565   if (Opc == TargetOpcode::LOCAL_ESCAPE) {
566     MachineOperand &FI = MI.getOperand(FIOperandNum);
567     int Offset;
568     Offset = TFI->getFrameIndexReference(MF, FrameIndex, IgnoredFrameReg);
569     FI.ChangeToImmediate(Offset);
570     return;
571   }
572 
573   // For LEA64_32r when BasePtr is 32-bits (X32) we can use full-size 64-bit
574   // register as source operand, semantic is the same and destination is
575   // 32-bits. It saves one byte per lea in code since 0x67 prefix is avoided.
576   if (Opc == X86::LEA64_32r && X86::GR32RegClass.contains(BasePtr))
577     BasePtr = getX86SubSuperRegister(BasePtr, MVT::i64, false);
578 
579   // This must be part of a four operand memory reference.  Replace the
580   // FrameIndex with base register with EBP.  Add an offset to the offset.
581   MI.getOperand(FIOperandNum).ChangeToRegister(BasePtr, false);
582 
583   // Now add the frame object offset to the offset from EBP.
584   int FIOffset;
585   if (AfterFPPop) {
586     // Tail call jmp happens after FP is popped.
587     const MachineFrameInfo *MFI = MF.getFrameInfo();
588     FIOffset = MFI->getObjectOffset(FrameIndex) - TFI->getOffsetOfLocalArea();
589   } else
590     FIOffset = TFI->getFrameIndexReference(MF, FrameIndex, IgnoredFrameReg);
591 
592   if (BasePtr == StackPtr)
593     FIOffset += SPAdj;
594 
595   // The frame index format for stackmaps and patchpoints is different from the
596   // X86 format. It only has a FI and an offset.
597   if (Opc == TargetOpcode::STACKMAP || Opc == TargetOpcode::PATCHPOINT) {
598     assert(BasePtr == FramePtr && "Expected the FP as base register");
599     int64_t Offset = MI.getOperand(FIOperandNum + 1).getImm() + FIOffset;
600     MI.getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);
601     return;
602   }
603 
604   if (MI.getOperand(FIOperandNum+3).isImm()) {
605     // Offset is a 32-bit integer.
606     int Imm = (int)(MI.getOperand(FIOperandNum + 3).getImm());
607     int Offset = FIOffset + Imm;
608     assert((!Is64Bit || isInt<32>((long long)FIOffset + Imm)) &&
609            "Requesting 64-bit offset in 32-bit immediate!");
610     MI.getOperand(FIOperandNum + 3).ChangeToImmediate(Offset);
611   } else {
612     // Offset is symbolic. This is extremely rare.
613     uint64_t Offset = FIOffset +
614       (uint64_t)MI.getOperand(FIOperandNum+3).getOffset();
615     MI.getOperand(FIOperandNum + 3).setOffset(Offset);
616   }
617 }
618 
getFrameRegister(const MachineFunction & MF) const619 unsigned X86RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
620   const X86FrameLowering *TFI = getFrameLowering(MF);
621   return TFI->hasFP(MF) ? FramePtr : StackPtr;
622 }
623 
624 unsigned
getPtrSizedFrameRegister(const MachineFunction & MF) const625 X86RegisterInfo::getPtrSizedFrameRegister(const MachineFunction &MF) const {
626   const X86Subtarget &Subtarget = MF.getSubtarget<X86Subtarget>();
627   unsigned FrameReg = getFrameRegister(MF);
628   if (Subtarget.isTarget64BitILP32())
629     FrameReg = getX86SubSuperRegister(FrameReg, MVT::i32, false);
630   return FrameReg;
631 }
632 
633 namespace llvm {
getX86SubSuperRegisterOrZero(unsigned Reg,MVT::SimpleValueType VT,bool High)634 unsigned getX86SubSuperRegisterOrZero(unsigned Reg, MVT::SimpleValueType VT,
635                                       bool High) {
636   switch (VT) {
637   default: return 0;
638   case MVT::i8:
639     if (High) {
640       switch (Reg) {
641       default: return getX86SubSuperRegister(Reg, MVT::i64);
642       case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
643         return X86::SI;
644       case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
645         return X86::DI;
646       case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
647         return X86::BP;
648       case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
649         return X86::SP;
650       case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
651         return X86::AH;
652       case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
653         return X86::DH;
654       case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
655         return X86::CH;
656       case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
657         return X86::BH;
658       }
659     } else {
660       switch (Reg) {
661       default: return 0;
662       case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
663         return X86::AL;
664       case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
665         return X86::DL;
666       case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
667         return X86::CL;
668       case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
669         return X86::BL;
670       case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
671         return X86::SIL;
672       case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
673         return X86::DIL;
674       case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
675         return X86::BPL;
676       case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
677         return X86::SPL;
678       case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
679         return X86::R8B;
680       case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
681         return X86::R9B;
682       case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
683         return X86::R10B;
684       case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
685         return X86::R11B;
686       case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
687         return X86::R12B;
688       case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
689         return X86::R13B;
690       case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
691         return X86::R14B;
692       case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
693         return X86::R15B;
694       }
695     }
696   case MVT::i16:
697     switch (Reg) {
698     default: return 0;
699     case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
700       return X86::AX;
701     case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
702       return X86::DX;
703     case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
704       return X86::CX;
705     case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
706       return X86::BX;
707     case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
708       return X86::SI;
709     case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
710       return X86::DI;
711     case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
712       return X86::BP;
713     case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
714       return X86::SP;
715     case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
716       return X86::R8W;
717     case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
718       return X86::R9W;
719     case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
720       return X86::R10W;
721     case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
722       return X86::R11W;
723     case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
724       return X86::R12W;
725     case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
726       return X86::R13W;
727     case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
728       return X86::R14W;
729     case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
730       return X86::R15W;
731     }
732   case MVT::i32:
733     switch (Reg) {
734     default: return 0;
735     case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
736       return X86::EAX;
737     case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
738       return X86::EDX;
739     case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
740       return X86::ECX;
741     case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
742       return X86::EBX;
743     case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
744       return X86::ESI;
745     case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
746       return X86::EDI;
747     case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
748       return X86::EBP;
749     case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
750       return X86::ESP;
751     case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
752       return X86::R8D;
753     case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
754       return X86::R9D;
755     case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
756       return X86::R10D;
757     case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
758       return X86::R11D;
759     case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
760       return X86::R12D;
761     case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
762       return X86::R13D;
763     case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
764       return X86::R14D;
765     case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
766       return X86::R15D;
767     }
768   case MVT::i64:
769     switch (Reg) {
770     default: return 0;
771     case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
772       return X86::RAX;
773     case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
774       return X86::RDX;
775     case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
776       return X86::RCX;
777     case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
778       return X86::RBX;
779     case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
780       return X86::RSI;
781     case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
782       return X86::RDI;
783     case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
784       return X86::RBP;
785     case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
786       return X86::RSP;
787     case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
788       return X86::R8;
789     case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
790       return X86::R9;
791     case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
792       return X86::R10;
793     case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
794       return X86::R11;
795     case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
796       return X86::R12;
797     case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
798       return X86::R13;
799     case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
800       return X86::R14;
801     case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
802       return X86::R15;
803     }
804   }
805 }
806 
getX86SubSuperRegister(unsigned Reg,MVT::SimpleValueType VT,bool High)807 unsigned getX86SubSuperRegister(unsigned Reg, MVT::SimpleValueType VT,
808                                 bool High) {
809   unsigned Res = getX86SubSuperRegisterOrZero(Reg, VT, High);
810   if (Res == 0)
811     llvm_unreachable("Unexpected register or VT");
812   return Res;
813 }
814 
get512BitSuperRegister(unsigned Reg)815 unsigned get512BitSuperRegister(unsigned Reg) {
816   if (Reg >= X86::XMM0 && Reg <= X86::XMM31)
817     return X86::ZMM0 + (Reg - X86::XMM0);
818   if (Reg >= X86::YMM0 && Reg <= X86::YMM31)
819     return X86::ZMM0 + (Reg - X86::YMM0);
820   if (Reg >= X86::ZMM0 && Reg <= X86::ZMM31)
821     return Reg;
822   llvm_unreachable("Unexpected SIMD register");
823 }
824 
825 }
826