1 //===- X86RegisterInfo.cpp - X86 Register Information -----------*- 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 the X86 implementation of the TargetRegisterInfo class.
11 // This file is responsible for the frame pointer elimination optimization
14 //===----------------------------------------------------------------------===//
17 #include "X86RegisterInfo.h"
18 #include "X86InstrBuilder.h"
19 #include "X86MachineFunctionInfo.h"
20 #include "X86Subtarget.h"
21 #include "X86TargetMachine.h"
22 #include "llvm/Constants.h"
23 #include "llvm/Function.h"
24 #include "llvm/Type.h"
25 #include "llvm/CodeGen/ValueTypes.h"
26 #include "llvm/CodeGen/MachineInstrBuilder.h"
27 #include "llvm/CodeGen/MachineFunction.h"
28 #include "llvm/CodeGen/MachineFunctionPass.h"
29 #include "llvm/CodeGen/MachineFrameInfo.h"
30 #include "llvm/CodeGen/MachineLocation.h"
31 #include "llvm/CodeGen/MachineModuleInfo.h"
32 #include "llvm/CodeGen/MachineRegisterInfo.h"
33 #include "llvm/MC/MCAsmInfo.h"
34 #include "llvm/Target/TargetFrameLowering.h"
35 #include "llvm/Target/TargetInstrInfo.h"
36 #include "llvm/Target/TargetMachine.h"
37 #include "llvm/Target/TargetOptions.h"
38 #include "llvm/ADT/BitVector.h"
39 #include "llvm/ADT/STLExtras.h"
40 #include "llvm/Support/ErrorHandling.h"
41 #include "llvm/Support/CommandLine.h"
43 #define GET_REGINFO_MC_DESC
44 #define GET_REGINFO_TARGET_DESC
45 #include "X86GenRegisterInfo.inc"
50 ForceStackAlign("force-align-stack",
51 cl::desc("Force align the stack to the minimum alignment"
52 " needed for the function."),
53 cl::init(false), cl::Hidden);
55 X86RegisterInfo::X86RegisterInfo(X86TargetMachine &tm,
56 const TargetInstrInfo &tii)
57 : X86GenRegisterInfo(tm.getSubtarget<X86Subtarget>().is64Bit() ?
58 X86::ADJCALLSTACKDOWN64 :
59 X86::ADJCALLSTACKDOWN32,
60 tm.getSubtarget<X86Subtarget>().is64Bit() ?
61 X86::ADJCALLSTACKUP64 :
62 X86::ADJCALLSTACKUP32),
64 // Cache some information.
65 const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
66 Is64Bit = Subtarget->is64Bit();
67 IsWin64 = Subtarget->isTargetWin64();
80 static unsigned getFlavour(const X86Subtarget *Subtarget, bool isEH) {
81 if (!Subtarget->is64Bit()) {
82 if (Subtarget->isTargetDarwin()) {
84 return DWARFFlavour::X86_32_DarwinEH;
86 return DWARFFlavour::X86_32_Generic;
87 } else if (Subtarget->isTargetCygMing()) {
88 // Unsupported by now, just quick fallback
89 return DWARFFlavour::X86_32_Generic;
91 return DWARFFlavour::X86_32_Generic;
94 return DWARFFlavour::X86_64;
97 /// getDwarfRegNum - This function maps LLVM register identifiers to the DWARF
98 /// specific numbering, used in debug info and exception tables.
99 int X86RegisterInfo::getDwarfRegNum(unsigned RegNo, bool isEH) const {
100 const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
101 unsigned Flavour = getFlavour(Subtarget, isEH);
103 return X86GenRegisterInfo::getDwarfRegNumFull(RegNo, Flavour);
106 /// getLLVMRegNum - This function maps DWARF register numbers to LLVM register.
107 int X86RegisterInfo::getLLVMRegNum(unsigned DwarfRegNo, bool isEH) const {
108 const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
109 unsigned Flavour = getFlavour(Subtarget, isEH);
111 return X86GenRegisterInfo::getLLVMRegNumFull(DwarfRegNo, Flavour);
115 X86RegisterInfo::getSEHRegNum(unsigned i) const {
116 int reg = getX86RegNum(i);
118 case X86::R8: case X86::R8D: case X86::R8W: case X86::R8B:
119 case X86::R9: case X86::R9D: case X86::R9W: case X86::R9B:
120 case X86::R10: case X86::R10D: case X86::R10W: case X86::R10B:
121 case X86::R11: case X86::R11D: case X86::R11W: case X86::R11B:
122 case X86::R12: case X86::R12D: case X86::R12W: case X86::R12B:
123 case X86::R13: case X86::R13D: case X86::R13W: case X86::R13B:
124 case X86::R14: case X86::R14D: case X86::R14W: case X86::R14B:
125 case X86::R15: case X86::R15D: case X86::R15W: case X86::R15B:
126 case X86::XMM8: case X86::XMM9: case X86::XMM10: case X86::XMM11:
127 case X86::XMM12: case X86::XMM13: case X86::XMM14: case X86::XMM15:
128 case X86::YMM8: case X86::YMM9: case X86::YMM10: case X86::YMM11:
129 case X86::YMM12: case X86::YMM13: case X86::YMM14: case X86::YMM15:
135 /// getX86RegNum - This function maps LLVM register identifiers to their X86
136 /// specific numbering, which is used in various places encoding instructions.
137 unsigned X86RegisterInfo::getX86RegNum(unsigned RegNo) {
139 case X86::RAX: case X86::EAX: case X86::AX: case X86::AL: return N86::EAX;
140 case X86::RCX: case X86::ECX: case X86::CX: case X86::CL: return N86::ECX;
141 case X86::RDX: case X86::EDX: case X86::DX: case X86::DL: return N86::EDX;
142 case X86::RBX: case X86::EBX: case X86::BX: case X86::BL: return N86::EBX;
143 case X86::RSP: case X86::ESP: case X86::SP: case X86::SPL: case X86::AH:
145 case X86::RBP: case X86::EBP: case X86::BP: case X86::BPL: case X86::CH:
147 case X86::RSI: case X86::ESI: case X86::SI: case X86::SIL: case X86::DH:
149 case X86::RDI: case X86::EDI: case X86::DI: case X86::DIL: case X86::BH:
152 case X86::R8: case X86::R8D: case X86::R8W: case X86::R8B:
154 case X86::R9: case X86::R9D: case X86::R9W: case X86::R9B:
156 case X86::R10: case X86::R10D: case X86::R10W: case X86::R10B:
158 case X86::R11: case X86::R11D: case X86::R11W: case X86::R11B:
160 case X86::R12: case X86::R12D: case X86::R12W: case X86::R12B:
162 case X86::R13: case X86::R13D: case X86::R13W: case X86::R13B:
164 case X86::R14: case X86::R14D: case X86::R14W: case X86::R14B:
166 case X86::R15: case X86::R15D: case X86::R15W: case X86::R15B:
169 case X86::ST0: case X86::ST1: case X86::ST2: case X86::ST3:
170 case X86::ST4: case X86::ST5: case X86::ST6: case X86::ST7:
171 return RegNo-X86::ST0;
173 case X86::XMM0: case X86::XMM8:
174 case X86::YMM0: case X86::YMM8: case X86::MM0:
176 case X86::XMM1: case X86::XMM9:
177 case X86::YMM1: case X86::YMM9: case X86::MM1:
179 case X86::XMM2: case X86::XMM10:
180 case X86::YMM2: case X86::YMM10: case X86::MM2:
182 case X86::XMM3: case X86::XMM11:
183 case X86::YMM3: case X86::YMM11: case X86::MM3:
185 case X86::XMM4: case X86::XMM12:
186 case X86::YMM4: case X86::YMM12: case X86::MM4:
188 case X86::XMM5: case X86::XMM13:
189 case X86::YMM5: case X86::YMM13: case X86::MM5:
191 case X86::XMM6: case X86::XMM14:
192 case X86::YMM6: case X86::YMM14: case X86::MM6:
194 case X86::XMM7: case X86::XMM15:
195 case X86::YMM7: case X86::YMM15: case X86::MM7:
198 case X86::ES: return 0;
199 case X86::CS: return 1;
200 case X86::SS: return 2;
201 case X86::DS: return 3;
202 case X86::FS: return 4;
203 case X86::GS: return 5;
205 case X86::CR0: case X86::CR8 : case X86::DR0: return 0;
206 case X86::CR1: case X86::CR9 : case X86::DR1: return 1;
207 case X86::CR2: case X86::CR10: case X86::DR2: return 2;
208 case X86::CR3: case X86::CR11: case X86::DR3: return 3;
209 case X86::CR4: case X86::CR12: case X86::DR4: return 4;
210 case X86::CR5: case X86::CR13: case X86::DR5: return 5;
211 case X86::CR6: case X86::CR14: case X86::DR6: return 6;
212 case X86::CR7: case X86::CR15: case X86::DR7: return 7;
214 // Pseudo index registers are equivalent to a "none"
215 // scaled index (See Intel Manual 2A, table 2-3)
221 assert(isVirtualRegister(RegNo) && "Unknown physical register!");
222 llvm_unreachable("Register allocator hasn't allocated reg correctly yet!");
227 const TargetRegisterClass *
228 X86RegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
229 const TargetRegisterClass *B,
230 unsigned SubIdx) const {
234 if (B == &X86::GR8RegClass) {
235 if (A->getSize() == 2 || A->getSize() == 4 || A->getSize() == 8)
237 } else if (B == &X86::GR8_ABCD_LRegClass || B == &X86::GR8_ABCD_HRegClass) {
238 if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
239 A == &X86::GR64_NOREXRegClass ||
240 A == &X86::GR64_NOSPRegClass ||
241 A == &X86::GR64_NOREX_NOSPRegClass)
242 return &X86::GR64_ABCDRegClass;
243 else if (A == &X86::GR32RegClass || A == &X86::GR32_ABCDRegClass ||
244 A == &X86::GR32_NOREXRegClass ||
245 A == &X86::GR32_NOSPRegClass)
246 return &X86::GR32_ABCDRegClass;
247 else if (A == &X86::GR16RegClass || A == &X86::GR16_ABCDRegClass ||
248 A == &X86::GR16_NOREXRegClass)
249 return &X86::GR16_ABCDRegClass;
250 } else if (B == &X86::GR8_NOREXRegClass) {
251 if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass ||
252 A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
253 return &X86::GR64_NOREXRegClass;
254 else if (A == &X86::GR64_ABCDRegClass)
255 return &X86::GR64_ABCDRegClass;
256 else if (A == &X86::GR32RegClass || A == &X86::GR32_NOREXRegClass ||
257 A == &X86::GR32_NOSPRegClass)
258 return &X86::GR32_NOREXRegClass;
259 else if (A == &X86::GR32_ABCDRegClass)
260 return &X86::GR32_ABCDRegClass;
261 else if (A == &X86::GR16RegClass || A == &X86::GR16_NOREXRegClass)
262 return &X86::GR16_NOREXRegClass;
263 else if (A == &X86::GR16_ABCDRegClass)
264 return &X86::GR16_ABCDRegClass;
267 case X86::sub_8bit_hi:
268 if (B->hasSubClassEq(&X86::GR8_ABCD_HRegClass))
269 switch (A->getSize()) {
270 case 2: return getCommonSubClass(A, &X86::GR16_ABCDRegClass);
271 case 4: return getCommonSubClass(A, &X86::GR32_ABCDRegClass);
272 case 8: return getCommonSubClass(A, &X86::GR64_ABCDRegClass);
277 if (B == &X86::GR16RegClass) {
278 if (A->getSize() == 4 || A->getSize() == 8)
280 } else if (B == &X86::GR16_ABCDRegClass) {
281 if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
282 A == &X86::GR64_NOREXRegClass ||
283 A == &X86::GR64_NOSPRegClass ||
284 A == &X86::GR64_NOREX_NOSPRegClass)
285 return &X86::GR64_ABCDRegClass;
286 else if (A == &X86::GR32RegClass || A == &X86::GR32_ABCDRegClass ||
287 A == &X86::GR32_NOREXRegClass || A == &X86::GR32_NOSPRegClass)
288 return &X86::GR32_ABCDRegClass;
289 } else if (B == &X86::GR16_NOREXRegClass) {
290 if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass ||
291 A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
292 return &X86::GR64_NOREXRegClass;
293 else if (A == &X86::GR64_ABCDRegClass)
294 return &X86::GR64_ABCDRegClass;
295 else if (A == &X86::GR32RegClass || A == &X86::GR32_NOREXRegClass ||
296 A == &X86::GR32_NOSPRegClass)
297 return &X86::GR32_NOREXRegClass;
298 else if (A == &X86::GR32_ABCDRegClass)
299 return &X86::GR64_ABCDRegClass;
303 if (B == &X86::GR32RegClass) {
304 if (A->getSize() == 8)
306 } else if (B == &X86::GR32_NOSPRegClass) {
307 if (A == &X86::GR64RegClass || A == &X86::GR64_NOSPRegClass)
308 return &X86::GR64_NOSPRegClass;
309 if (A->getSize() == 8)
310 return getCommonSubClass(A, &X86::GR64_NOSPRegClass);
311 } else if (B == &X86::GR32_ABCDRegClass) {
312 if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
313 A == &X86::GR64_NOREXRegClass ||
314 A == &X86::GR64_NOSPRegClass ||
315 A == &X86::GR64_NOREX_NOSPRegClass)
316 return &X86::GR64_ABCDRegClass;
317 } else if (B == &X86::GR32_NOREXRegClass) {
318 if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass)
319 return &X86::GR64_NOREXRegClass;
320 else if (A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
321 return &X86::GR64_NOREX_NOSPRegClass;
322 else if (A == &X86::GR64_ABCDRegClass)
323 return &X86::GR64_ABCDRegClass;
324 } else if (B == &X86::GR32_NOREX_NOSPRegClass) {
325 if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass ||
326 A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
327 return &X86::GR64_NOREX_NOSPRegClass;
328 else if (A == &X86::GR64_ABCDRegClass)
329 return &X86::GR64_ABCDRegClass;
333 if (B == &X86::FR32RegClass)
337 if (B == &X86::FR64RegClass)
341 if (B == &X86::VR128RegClass)
348 const TargetRegisterClass*
349 X86RegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC) const{
350 const TargetRegisterClass *Super = RC;
351 TargetRegisterClass::sc_iterator I = RC->superclasses_begin();
353 switch (Super->getID()) {
354 case X86::GR8RegClassID:
355 case X86::GR16RegClassID:
356 case X86::GR32RegClassID:
357 case X86::GR64RegClassID:
358 case X86::FR32RegClassID:
359 case X86::FR64RegClassID:
360 case X86::RFP32RegClassID:
361 case X86::RFP64RegClassID:
362 case X86::RFP80RegClassID:
363 case X86::VR128RegClassID:
364 case X86::VR256RegClassID:
365 // Don't return a super-class that would shrink the spill size.
366 // That can happen with the vector and float classes.
367 if (Super->getSize() == RC->getSize())
375 const TargetRegisterClass *
376 X86RegisterInfo::getPointerRegClass(unsigned Kind) const {
378 default: llvm_unreachable("Unexpected Kind in getPointerRegClass!");
379 case 0: // Normal GPRs.
380 if (TM.getSubtarget<X86Subtarget>().is64Bit())
381 return &X86::GR64RegClass;
382 return &X86::GR32RegClass;
383 case 1: // Normal GPRs except the stack pointer (for encoding reasons).
384 if (TM.getSubtarget<X86Subtarget>().is64Bit())
385 return &X86::GR64_NOSPRegClass;
386 return &X86::GR32_NOSPRegClass;
387 case 2: // Available for tailcall (not callee-saved GPRs).
388 if (TM.getSubtarget<X86Subtarget>().isTargetWin64())
389 return &X86::GR64_TCW64RegClass;
390 if (TM.getSubtarget<X86Subtarget>().is64Bit())
391 return &X86::GR64_TCRegClass;
392 return &X86::GR32_TCRegClass;
396 const TargetRegisterClass *
397 X86RegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
398 if (RC == &X86::CCRRegClass) {
400 return &X86::GR64RegClass;
402 return &X86::GR32RegClass;
408 X86RegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
409 MachineFunction &MF) const {
410 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
412 unsigned FPDiff = TFI->hasFP(MF) ? 1 : 0;
413 switch (RC->getID()) {
416 case X86::GR32RegClassID:
418 case X86::GR64RegClassID:
420 case X86::VR128RegClassID:
421 return TM.getSubtarget<X86Subtarget>().is64Bit() ? 10 : 4;
422 case X86::VR64RegClassID:
428 X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
429 bool callsEHReturn = false;
430 bool ghcCall = false;
433 callsEHReturn = MF->getMMI().callsEHReturn();
434 const Function *F = MF->getFunction();
435 ghcCall = (F ? F->getCallingConv() == CallingConv::GHC : false);
438 static const unsigned GhcCalleeSavedRegs[] = {
442 static const unsigned CalleeSavedRegs32Bit[] = {
443 X86::ESI, X86::EDI, X86::EBX, X86::EBP, 0
446 static const unsigned CalleeSavedRegs32EHRet[] = {
447 X86::EAX, X86::EDX, X86::ESI, X86::EDI, X86::EBX, X86::EBP, 0
450 static const unsigned CalleeSavedRegs64Bit[] = {
451 X86::RBX, X86::R12, X86::R13, X86::R14, X86::R15, X86::RBP, 0
454 static const unsigned CalleeSavedRegs64EHRet[] = {
455 X86::RAX, X86::RDX, X86::RBX, X86::R12,
456 X86::R13, X86::R14, X86::R15, X86::RBP, 0
459 static const unsigned CalleeSavedRegsWin64[] = {
460 X86::RBX, X86::RBP, X86::RDI, X86::RSI,
461 X86::R12, X86::R13, X86::R14, X86::R15,
462 X86::XMM6, X86::XMM7, X86::XMM8, X86::XMM9,
463 X86::XMM10, X86::XMM11, X86::XMM12, X86::XMM13,
464 X86::XMM14, X86::XMM15, 0
468 return GhcCalleeSavedRegs;
469 } else if (Is64Bit) {
471 return CalleeSavedRegsWin64;
473 return (callsEHReturn ? CalleeSavedRegs64EHRet : CalleeSavedRegs64Bit);
475 return (callsEHReturn ? CalleeSavedRegs32EHRet : CalleeSavedRegs32Bit);
479 BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
480 BitVector Reserved(getNumRegs());
481 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
483 // Set the stack-pointer register and its aliases as reserved.
484 Reserved.set(X86::RSP);
485 Reserved.set(X86::ESP);
486 Reserved.set(X86::SP);
487 Reserved.set(X86::SPL);
489 // Set the instruction pointer register and its aliases as reserved.
490 Reserved.set(X86::RIP);
491 Reserved.set(X86::EIP);
492 Reserved.set(X86::IP);
494 // Set the frame-pointer register and its aliases as reserved if needed.
495 if (TFI->hasFP(MF)) {
496 Reserved.set(X86::RBP);
497 Reserved.set(X86::EBP);
498 Reserved.set(X86::BP);
499 Reserved.set(X86::BPL);
502 // Mark the segment registers as reserved.
503 Reserved.set(X86::CS);
504 Reserved.set(X86::SS);
505 Reserved.set(X86::DS);
506 Reserved.set(X86::ES);
507 Reserved.set(X86::FS);
508 Reserved.set(X86::GS);
510 // Reserve the registers that only exist in 64-bit mode.
512 // These 8-bit registers are part of the x86-64 extension even though their
513 // super-registers are old 32-bits.
514 Reserved.set(X86::SIL);
515 Reserved.set(X86::DIL);
516 Reserved.set(X86::BPL);
517 Reserved.set(X86::SPL);
519 for (unsigned n = 0; n != 8; ++n) {
521 const unsigned GPR64[] = {
522 X86::R8, X86::R9, X86::R10, X86::R11,
523 X86::R12, X86::R13, X86::R14, X86::R15
525 for (const unsigned *AI = getOverlaps(GPR64[n]); unsigned Reg = *AI; ++AI)
529 assert(X86::XMM15 == X86::XMM8+7);
530 for (const unsigned *AI = getOverlaps(X86::XMM8 + n); unsigned Reg = *AI;
539 //===----------------------------------------------------------------------===//
540 // Stack Frame Processing methods
541 //===----------------------------------------------------------------------===//
543 bool X86RegisterInfo::canRealignStack(const MachineFunction &MF) const {
544 const MachineFrameInfo *MFI = MF.getFrameInfo();
545 return (RealignStack &&
546 !MFI->hasVarSizedObjects());
549 bool X86RegisterInfo::needsStackRealignment(const MachineFunction &MF) const {
550 const MachineFrameInfo *MFI = MF.getFrameInfo();
551 const Function *F = MF.getFunction();
552 unsigned StackAlign = TM.getFrameLowering()->getStackAlignment();
553 bool requiresRealignment = ((MFI->getMaxAlignment() > StackAlign) ||
554 F->hasFnAttr(Attribute::StackAlignment));
556 // FIXME: Currently we don't support stack realignment for functions with
557 // variable-sized allocas.
558 // FIXME: It's more complicated than this...
559 if (0 && requiresRealignment && MFI->hasVarSizedObjects())
561 "Stack realignment in presence of dynamic allocas is not supported");
563 // If we've requested that we force align the stack do so now.
565 return canRealignStack(MF);
567 return requiresRealignment && canRealignStack(MF);
570 bool X86RegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
571 unsigned Reg, int &FrameIdx) const {
572 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
574 if (Reg == FramePtr && TFI->hasFP(MF)) {
575 FrameIdx = MF.getFrameInfo()->getObjectIndexBegin();
581 static unsigned getSUBriOpcode(unsigned is64Bit, int64_t Imm) {
584 return X86::SUB64ri8;
585 return X86::SUB64ri32;
588 return X86::SUB32ri8;
593 static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) {
596 return X86::ADD64ri8;
597 return X86::ADD64ri32;
600 return X86::ADD32ri8;
605 void X86RegisterInfo::
606 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
607 MachineBasicBlock::iterator I) const {
608 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
609 bool reseveCallFrame = TFI->hasReservedCallFrame(MF);
610 int Opcode = I->getOpcode();
611 bool isDestroy = Opcode == getCallFrameDestroyOpcode();
612 DebugLoc DL = I->getDebugLoc();
613 uint64_t Amount = !reseveCallFrame ? I->getOperand(0).getImm() : 0;
614 uint64_t CalleeAmt = isDestroy ? I->getOperand(1).getImm() : 0;
617 if (!reseveCallFrame) {
618 // If the stack pointer can be changed after prologue, turn the
619 // adjcallstackup instruction into a 'sub ESP, <amt>' and the
620 // adjcallstackdown instruction into 'add ESP, <amt>'
621 // TODO: consider using push / pop instead of sub + store / add
625 // We need to keep the stack aligned properly. To do this, we round the
626 // amount of space needed for the outgoing arguments up to the next
627 // alignment boundary.
628 unsigned StackAlign = TM.getFrameLowering()->getStackAlignment();
629 Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign;
631 MachineInstr *New = 0;
632 if (Opcode == getCallFrameSetupOpcode()) {
633 New = BuildMI(MF, DL, TII.get(getSUBriOpcode(Is64Bit, Amount)),
638 assert(Opcode == getCallFrameDestroyOpcode());
640 // Factor out the amount the callee already popped.
644 unsigned Opc = getADDriOpcode(Is64Bit, Amount);
645 New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
646 .addReg(StackPtr).addImm(Amount);
651 // The EFLAGS implicit def is dead.
652 New->getOperand(3).setIsDead();
654 // Replace the pseudo instruction with a new instruction.
661 if (Opcode == getCallFrameDestroyOpcode() && CalleeAmt) {
662 // If we are performing frame pointer elimination and if the callee pops
663 // something off the stack pointer, add it back. We do this until we have
664 // more advanced stack pointer tracking ability.
665 unsigned Opc = getSUBriOpcode(Is64Bit, CalleeAmt);
666 MachineInstr *New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
667 .addReg(StackPtr).addImm(CalleeAmt);
669 // The EFLAGS implicit def is dead.
670 New->getOperand(3).setIsDead();
676 X86RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
677 int SPAdj, RegScavenger *RS) const{
678 assert(SPAdj == 0 && "Unexpected");
681 MachineInstr &MI = *II;
682 MachineFunction &MF = *MI.getParent()->getParent();
683 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
685 while (!MI.getOperand(i).isFI()) {
687 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
690 int FrameIndex = MI.getOperand(i).getIndex();
693 unsigned Opc = MI.getOpcode();
694 bool AfterFPPop = Opc == X86::TAILJMPm64 || Opc == X86::TAILJMPm;
695 if (needsStackRealignment(MF))
696 BasePtr = (FrameIndex < 0 ? FramePtr : StackPtr);
700 BasePtr = (TFI->hasFP(MF) ? FramePtr : StackPtr);
702 // This must be part of a four operand memory reference. Replace the
703 // FrameIndex with base register with EBP. Add an offset to the offset.
704 MI.getOperand(i).ChangeToRegister(BasePtr, false);
706 // Now add the frame object offset to the offset from EBP.
709 // Tail call jmp happens after FP is popped.
710 const MachineFrameInfo *MFI = MF.getFrameInfo();
711 FIOffset = MFI->getObjectOffset(FrameIndex) - TFI->getOffsetOfLocalArea();
713 FIOffset = TFI->getFrameIndexOffset(MF, FrameIndex);
715 if (MI.getOperand(i+3).isImm()) {
716 // Offset is a 32-bit integer.
717 int Offset = FIOffset + (int)(MI.getOperand(i + 3).getImm());
718 MI.getOperand(i + 3).ChangeToImmediate(Offset);
720 // Offset is symbolic. This is extremely rare.
721 uint64_t Offset = FIOffset + (uint64_t)MI.getOperand(i+3).getOffset();
722 MI.getOperand(i+3).setOffset(Offset);
726 unsigned X86RegisterInfo::getRARegister() const {
727 return Is64Bit ? X86::RIP // Should have dwarf #16.
728 : X86::EIP; // Should have dwarf #8.
731 unsigned X86RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
732 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
733 return TFI->hasFP(MF) ? FramePtr : StackPtr;
736 unsigned X86RegisterInfo::getEHExceptionRegister() const {
737 llvm_unreachable("What is the exception register");
741 unsigned X86RegisterInfo::getEHHandlerRegister() const {
742 llvm_unreachable("What is the exception handler register");
747 unsigned getX86SubSuperRegister(unsigned Reg, EVT VT, bool High) {
748 switch (VT.getSimpleVT().SimpleTy) {
754 case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
756 case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
758 case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
760 case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
766 case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
768 case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
770 case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
772 case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
774 case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
776 case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
778 case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
780 case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
782 case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
784 case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
786 case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
788 case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
790 case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
792 case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
794 case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
796 case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
803 case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
805 case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
807 case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
809 case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
811 case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
813 case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
815 case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
817 case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
819 case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
821 case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
823 case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
825 case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
827 case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
829 case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
831 case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
833 case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
839 case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
841 case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
843 case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
845 case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
847 case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
849 case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
851 case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
853 case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
855 case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
857 case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
859 case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
861 case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
863 case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
865 case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
867 case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
869 case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
875 case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
877 case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
879 case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
881 case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
883 case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
885 case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
887 case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
889 case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
891 case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
893 case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
895 case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
897 case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
899 case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
901 case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
903 case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
905 case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
915 struct MSAH : public MachineFunctionPass {
917 MSAH() : MachineFunctionPass(ID) {}
919 virtual bool runOnMachineFunction(MachineFunction &MF) {
920 const X86TargetMachine *TM =
921 static_cast<const X86TargetMachine *>(&MF.getTarget());
922 const TargetFrameLowering *TFI = TM->getFrameLowering();
923 MachineRegisterInfo &RI = MF.getRegInfo();
924 X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
925 unsigned StackAlignment = TFI->getStackAlignment();
927 // Be over-conservative: scan over all vreg defs and find whether vector
928 // registers are used. If yes, there is a possibility that vector register
929 // will be spilled and thus require dynamic stack realignment.
930 for (unsigned i = 0, e = RI.getNumVirtRegs(); i != e; ++i) {
931 unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
932 if (RI.getRegClass(Reg)->getAlignment() > StackAlignment) {
933 FuncInfo->setReserveFP(true);
941 virtual const char *getPassName() const {
942 return "X86 Maximal Stack Alignment Check";
945 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
946 AU.setPreservesCFG();
947 MachineFunctionPass::getAnalysisUsage(AU);
955 llvm::createX86MaxStackAlignmentHeuristicPass() { return new MSAH(); }