xref: /llvm-project/llvm/lib/Target/Mips/MipsAsmPrinter.cpp (revision 6fa1647a470c333c183a78805c3bb9d824c2befb)
1 //===- MipsAsmPrinter.cpp - Mips LLVM Assembly Printer --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains a printer that converts from our internal representation
10 // of machine-dependent LLVM code to GAS-format MIPS assembly language.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MipsAsmPrinter.h"
15 #include "MCTargetDesc/MipsABIInfo.h"
16 #include "MCTargetDesc/MipsBaseInfo.h"
17 #include "MCTargetDesc/MipsInstPrinter.h"
18 #include "MCTargetDesc/MipsMCNaCl.h"
19 #include "MCTargetDesc/MipsMCTargetDesc.h"
20 #include "Mips.h"
21 #include "MipsMCInstLower.h"
22 #include "MipsMachineFunction.h"
23 #include "MipsSubtarget.h"
24 #include "MipsTargetMachine.h"
25 #include "MipsTargetStreamer.h"
26 #include "TargetInfo/MipsTargetInfo.h"
27 #include "llvm/ADT/SmallString.h"
28 #include "llvm/ADT/StringRef.h"
29 #include "llvm/ADT/Twine.h"
30 #include "llvm/BinaryFormat/ELF.h"
31 #include "llvm/CodeGen/MachineBasicBlock.h"
32 #include "llvm/CodeGen/MachineConstantPool.h"
33 #include "llvm/CodeGen/MachineFrameInfo.h"
34 #include "llvm/CodeGen/MachineFunction.h"
35 #include "llvm/CodeGen/MachineInstr.h"
36 #include "llvm/CodeGen/MachineJumpTableInfo.h"
37 #include "llvm/CodeGen/MachineOperand.h"
38 #include "llvm/CodeGen/TargetRegisterInfo.h"
39 #include "llvm/CodeGen/TargetSubtargetInfo.h"
40 #include "llvm/IR/Attributes.h"
41 #include "llvm/IR/BasicBlock.h"
42 #include "llvm/IR/DataLayout.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/InlineAsm.h"
45 #include "llvm/IR/Instructions.h"
46 #include "llvm/IR/Module.h"
47 #include "llvm/MC/MCContext.h"
48 #include "llvm/MC/MCExpr.h"
49 #include "llvm/MC/MCInst.h"
50 #include "llvm/MC/MCInstBuilder.h"
51 #include "llvm/MC/MCObjectFileInfo.h"
52 #include "llvm/MC/MCSectionELF.h"
53 #include "llvm/MC/MCSymbol.h"
54 #include "llvm/MC/MCSymbolELF.h"
55 #include "llvm/MC/TargetRegistry.h"
56 #include "llvm/Support/Casting.h"
57 #include "llvm/Support/ErrorHandling.h"
58 #include "llvm/Support/raw_ostream.h"
59 #include "llvm/Target/TargetLoweringObjectFile.h"
60 #include "llvm/Target/TargetMachine.h"
61 #include "llvm/TargetParser/Triple.h"
62 #include <cassert>
63 #include <cstdint>
64 #include <map>
65 #include <memory>
66 #include <string>
67 #include <vector>
68 
69 using namespace llvm;
70 
71 #define DEBUG_TYPE "mips-asm-printer"
72 
73 extern cl::opt<bool> EmitJalrReloc;
74 
75 MipsTargetStreamer &MipsAsmPrinter::getTargetStreamer() const {
76   return static_cast<MipsTargetStreamer &>(*OutStreamer->getTargetStreamer());
77 }
78 
79 bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
80   Subtarget = &MF.getSubtarget<MipsSubtarget>();
81 
82   MipsFI = MF.getInfo<MipsFunctionInfo>();
83   if (Subtarget->inMips16Mode())
84     for (const auto &I : MipsFI->StubsNeeded)
85       StubsNeeded.insert(I);
86   MCP = MF.getConstantPool();
87 
88   // In NaCl, all indirect jump targets must be aligned to bundle size.
89   if (Subtarget->isTargetNaCl())
90     NaClAlignIndirectJumpTargets(MF);
91 
92   AsmPrinter::runOnMachineFunction(MF);
93 
94   emitXRayTable();
95 
96   return true;
97 }
98 
99 bool MipsAsmPrinter::lowerOperand(const MachineOperand &MO, MCOperand &MCOp) {
100   MCOp = MCInstLowering.LowerOperand(MO);
101   return MCOp.isValid();
102 }
103 
104 #include "MipsGenMCPseudoLowering.inc"
105 
106 // Lower PseudoReturn/PseudoIndirectBranch/PseudoIndirectBranch64 to JR, JR_MM,
107 // JALR, or JALR64 as appropriate for the target.
108 void MipsAsmPrinter::emitPseudoIndirectBranch(MCStreamer &OutStreamer,
109                                               const MachineInstr *MI) {
110   bool HasLinkReg = false;
111   bool InMicroMipsMode = Subtarget->inMicroMipsMode();
112   MCInst TmpInst0;
113 
114   if (Subtarget->hasMips64r6()) {
115     // MIPS64r6 should use (JALR64 ZERO_64, $rs)
116     TmpInst0.setOpcode(Mips::JALR64);
117     HasLinkReg = true;
118   } else if (Subtarget->hasMips32r6()) {
119     // MIPS32r6 should use (JALR ZERO, $rs)
120     if (InMicroMipsMode)
121       TmpInst0.setOpcode(Mips::JRC16_MMR6);
122     else {
123       TmpInst0.setOpcode(Mips::JALR);
124       HasLinkReg = true;
125     }
126   } else if (Subtarget->inMicroMipsMode())
127     // microMIPS should use (JR_MM $rs)
128     TmpInst0.setOpcode(Mips::JR_MM);
129   else {
130     // Everything else should use (JR $rs)
131     TmpInst0.setOpcode(Mips::JR);
132   }
133 
134   MCOperand MCOp;
135 
136   if (HasLinkReg) {
137     unsigned ZeroReg = Subtarget->isGP64bit() ? Mips::ZERO_64 : Mips::ZERO;
138     TmpInst0.addOperand(MCOperand::createReg(ZeroReg));
139   }
140 
141   lowerOperand(MI->getOperand(0), MCOp);
142   TmpInst0.addOperand(MCOp);
143 
144   EmitToStreamer(OutStreamer, TmpInst0);
145 }
146 
147 // If there is an MO_JALR operand, insert:
148 //
149 // .reloc tmplabel, R_{MICRO}MIPS_JALR, symbol
150 // tmplabel:
151 //
152 // This is an optimization hint for the linker which may then replace
153 // an indirect call with a direct branch.
154 static void emitDirectiveRelocJalr(const MachineInstr &MI,
155                                    MCContext &OutContext,
156                                    TargetMachine &TM,
157                                    MCStreamer &OutStreamer,
158                                    const MipsSubtarget &Subtarget) {
159   for (const MachineOperand &MO :
160        llvm::drop_begin(MI.operands(), MI.getDesc().getNumOperands())) {
161     if (MO.isMCSymbol() && (MO.getTargetFlags() & MipsII::MO_JALR)) {
162       MCSymbol *Callee = MO.getMCSymbol();
163       if (Callee && !Callee->getName().empty()) {
164         MCSymbol *OffsetLabel = OutContext.createTempSymbol();
165         const MCExpr *OffsetExpr =
166             MCSymbolRefExpr::create(OffsetLabel, OutContext);
167         const MCExpr *CaleeExpr =
168             MCSymbolRefExpr::create(Callee, OutContext);
169         OutStreamer.emitRelocDirective(
170             *OffsetExpr,
171             Subtarget.inMicroMipsMode() ? "R_MICROMIPS_JALR" : "R_MIPS_JALR",
172             CaleeExpr, SMLoc(), *TM.getMCSubtargetInfo());
173         OutStreamer.emitLabel(OffsetLabel);
174         return;
175       }
176     }
177   }
178 }
179 
180 void MipsAsmPrinter::emitInstruction(const MachineInstr *MI) {
181   // FIXME: Enable feature predicate checks once all the test pass.
182   // Mips_MC::verifyInstructionPredicates(MI->getOpcode(),
183   //                                      getSubtargetInfo().getFeatureBits());
184 
185   MipsTargetStreamer &TS = getTargetStreamer();
186   unsigned Opc = MI->getOpcode();
187   TS.forbidModuleDirective();
188 
189   if (MI->isDebugValue()) {
190     SmallString<128> Str;
191     raw_svector_ostream OS(Str);
192 
193     PrintDebugValueComment(MI, OS);
194     return;
195   }
196   if (MI->isDebugLabel())
197     return;
198 
199   // If we just ended a constant pool, mark it as such.
200   if (InConstantPool && Opc != Mips::CONSTPOOL_ENTRY) {
201     OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
202     InConstantPool = false;
203   }
204   if (Opc == Mips::CONSTPOOL_ENTRY) {
205     // CONSTPOOL_ENTRY - This instruction represents a floating
206     // constant pool in the function.  The first operand is the ID#
207     // for this instruction, the second is the index into the
208     // MachineConstantPool that this is, the third is the size in
209     // bytes of this constant pool entry.
210     // The required alignment is specified on the basic block holding this MI.
211     //
212     unsigned LabelId = (unsigned)MI->getOperand(0).getImm();
213     unsigned CPIdx = (unsigned)MI->getOperand(1).getIndex();
214 
215     // If this is the first entry of the pool, mark it.
216     if (!InConstantPool) {
217       OutStreamer->emitDataRegion(MCDR_DataRegion);
218       InConstantPool = true;
219     }
220 
221     OutStreamer->emitLabel(GetCPISymbol(LabelId));
222 
223     const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx];
224     if (MCPE.isMachineConstantPoolEntry())
225       emitMachineConstantPoolValue(MCPE.Val.MachineCPVal);
226     else
227       emitGlobalConstant(MF->getDataLayout(), MCPE.Val.ConstVal);
228     return;
229   }
230 
231   switch (Opc) {
232   case Mips::PATCHABLE_FUNCTION_ENTER:
233     LowerPATCHABLE_FUNCTION_ENTER(*MI);
234     return;
235   case Mips::PATCHABLE_FUNCTION_EXIT:
236     LowerPATCHABLE_FUNCTION_EXIT(*MI);
237     return;
238   case Mips::PATCHABLE_TAIL_CALL:
239     LowerPATCHABLE_TAIL_CALL(*MI);
240     return;
241   }
242 
243   if (EmitJalrReloc &&
244       (MI->isReturn() || MI->isCall() || MI->isIndirectBranch())) {
245     emitDirectiveRelocJalr(*MI, OutContext, TM, *OutStreamer, *Subtarget);
246   }
247 
248   MachineBasicBlock::const_instr_iterator I = MI->getIterator();
249   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
250 
251   do {
252     // Do any auto-generated pseudo lowerings.
253     if (MCInst OutInst; lowerPseudoInstExpansion(&*I, OutInst)) {
254       EmitToStreamer(*OutStreamer, OutInst);
255       continue;
256     }
257 
258     // Skip the BUNDLE pseudo instruction and lower the contents
259     if (I->isBundle())
260       continue;
261 
262     if (I->getOpcode() == Mips::PseudoReturn ||
263         I->getOpcode() == Mips::PseudoReturn64 ||
264         I->getOpcode() == Mips::PseudoIndirectBranch ||
265         I->getOpcode() == Mips::PseudoIndirectBranch64 ||
266         I->getOpcode() == Mips::TAILCALLREG ||
267         I->getOpcode() == Mips::TAILCALLREG64) {
268       emitPseudoIndirectBranch(*OutStreamer, &*I);
269       continue;
270     }
271 
272     // The inMips16Mode() test is not permanent.
273     // Some instructions are marked as pseudo right now which
274     // would make the test fail for the wrong reason but
275     // that will be fixed soon. We need this here because we are
276     // removing another test for this situation downstream in the
277     // callchain.
278     //
279     if (I->isPseudo() && !Subtarget->inMips16Mode()
280         && !isLongBranchPseudo(I->getOpcode()))
281       llvm_unreachable("Pseudo opcode found in emitInstruction()");
282 
283     MCInst TmpInst0;
284     MCInstLowering.Lower(&*I, TmpInst0);
285     EmitToStreamer(*OutStreamer, TmpInst0);
286   } while ((++I != E) && I->isInsideBundle()); // Delay slot check
287 }
288 
289 //===----------------------------------------------------------------------===//
290 //
291 //  Mips Asm Directives
292 //
293 //  -- Frame directive "frame Stackpointer, Stacksize, RARegister"
294 //  Describe the stack frame.
295 //
296 //  -- Mask directives "(f)mask  bitmask, offset"
297 //  Tells the assembler which registers are saved and where.
298 //  bitmask - contain a little endian bitset indicating which registers are
299 //            saved on function prologue (e.g. with a 0x80000000 mask, the
300 //            assembler knows the register 31 (RA) is saved at prologue.
301 //  offset  - the position before stack pointer subtraction indicating where
302 //            the first saved register on prologue is located. (e.g. with a
303 //
304 //  Consider the following function prologue:
305 //
306 //    .frame  $fp,48,$ra
307 //    .mask   0xc0000000,-8
308 //       addiu $sp, $sp, -48
309 //       sw $ra, 40($sp)
310 //       sw $fp, 36($sp)
311 //
312 //    With a 0xc0000000 mask, the assembler knows the register 31 (RA) and
313 //    30 (FP) are saved at prologue. As the save order on prologue is from
314 //    left to right, RA is saved first. A -8 offset means that after the
315 //    stack pointer subtration, the first register in the mask (RA) will be
316 //    saved at address 48-8=40.
317 //
318 //===----------------------------------------------------------------------===//
319 
320 //===----------------------------------------------------------------------===//
321 // Mask directives
322 //===----------------------------------------------------------------------===//
323 
324 // Create a bitmask with all callee saved registers for CPU or Floating Point
325 // registers. For CPU registers consider RA, GP and FP for saving if necessary.
326 void MipsAsmPrinter::printSavedRegsBitmask() {
327   // CPU and FPU Saved Registers Bitmasks
328   unsigned CPUBitmask = 0, FPUBitmask = 0;
329   int CPUTopSavedRegOff, FPUTopSavedRegOff;
330 
331   // Set the CPU and FPU Bitmasks
332   const MachineFrameInfo &MFI = MF->getFrameInfo();
333   const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
334   const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
335   // size of stack area to which FP callee-saved regs are saved.
336   unsigned CPURegSize = TRI->getRegSizeInBits(Mips::GPR32RegClass) / 8;
337   unsigned FGR32RegSize = TRI->getRegSizeInBits(Mips::FGR32RegClass) / 8;
338   unsigned AFGR64RegSize = TRI->getRegSizeInBits(Mips::AFGR64RegClass) / 8;
339   bool HasAFGR64Reg = false;
340   unsigned CSFPRegsSize = 0;
341 
342   for (const auto &I : CSI) {
343     Register Reg = I.getReg();
344     unsigned RegNum = TRI->getEncodingValue(Reg);
345 
346     // If it's a floating point register, set the FPU Bitmask.
347     // If it's a general purpose register, set the CPU Bitmask.
348     if (Mips::FGR32RegClass.contains(Reg)) {
349       FPUBitmask |= (1 << RegNum);
350       CSFPRegsSize += FGR32RegSize;
351     } else if (Mips::AFGR64RegClass.contains(Reg)) {
352       FPUBitmask |= (3 << RegNum);
353       CSFPRegsSize += AFGR64RegSize;
354       HasAFGR64Reg = true;
355     } else if (Mips::GPR32RegClass.contains(Reg))
356       CPUBitmask |= (1 << RegNum);
357   }
358 
359   // FP Regs are saved right below where the virtual frame pointer points to.
360   FPUTopSavedRegOff = FPUBitmask ?
361     (HasAFGR64Reg ? -AFGR64RegSize : -FGR32RegSize) : 0;
362 
363   // CPU Regs are saved below FP Regs.
364   CPUTopSavedRegOff = CPUBitmask ? -CSFPRegsSize - CPURegSize : 0;
365 
366   MipsTargetStreamer &TS = getTargetStreamer();
367   // Print CPUBitmask
368   TS.emitMask(CPUBitmask, CPUTopSavedRegOff);
369 
370   // Print FPUBitmask
371   TS.emitFMask(FPUBitmask, FPUTopSavedRegOff);
372 }
373 
374 //===----------------------------------------------------------------------===//
375 // Frame and Set directives
376 //===----------------------------------------------------------------------===//
377 
378 /// Frame Directive
379 void MipsAsmPrinter::emitFrameDirective() {
380   const TargetRegisterInfo &RI = *MF->getSubtarget().getRegisterInfo();
381 
382   Register stackReg = RI.getFrameRegister(*MF);
383   unsigned returnReg = RI.getRARegister();
384   unsigned stackSize = MF->getFrameInfo().getStackSize();
385 
386   getTargetStreamer().emitFrame(stackReg, stackSize, returnReg);
387 }
388 
389 /// Emit Set directives.
390 const char *MipsAsmPrinter::getCurrentABIString() const {
391   switch (static_cast<MipsTargetMachine &>(TM).getABI().GetEnumValue()) {
392   case MipsABIInfo::ABI::O32:  return "abi32";
393   case MipsABIInfo::ABI::N32:  return "abiN32";
394   case MipsABIInfo::ABI::N64:  return "abi64";
395   default: llvm_unreachable("Unknown Mips ABI");
396   }
397 }
398 
399 void MipsAsmPrinter::emitFunctionEntryLabel() {
400   MipsTargetStreamer &TS = getTargetStreamer();
401 
402   // NaCl sandboxing requires that indirect call instructions are masked.
403   // This means that function entry points should be bundle-aligned.
404   if (Subtarget->isTargetNaCl())
405     emitAlignment(std::max(MF->getAlignment(), MIPS_NACL_BUNDLE_ALIGN));
406 
407   if (Subtarget->inMicroMipsMode()) {
408     TS.emitDirectiveSetMicroMips();
409     TS.setUsesMicroMips();
410     TS.updateABIInfo(*Subtarget);
411   } else
412     TS.emitDirectiveSetNoMicroMips();
413 
414   if (Subtarget->inMips16Mode())
415     TS.emitDirectiveSetMips16();
416   else
417     TS.emitDirectiveSetNoMips16();
418 
419   TS.emitDirectiveEnt(*CurrentFnSym);
420   OutStreamer->emitLabel(CurrentFnSym);
421 }
422 
423 /// EmitFunctionBodyStart - Targets can override this to emit stuff before
424 /// the first basic block in the function.
425 void MipsAsmPrinter::emitFunctionBodyStart() {
426   MipsTargetStreamer &TS = getTargetStreamer();
427 
428   MCInstLowering.Initialize(&MF->getContext());
429 
430   bool IsNakedFunction = MF->getFunction().hasFnAttribute(Attribute::Naked);
431   if (!IsNakedFunction)
432     emitFrameDirective();
433 
434   if (!IsNakedFunction)
435     printSavedRegsBitmask();
436 
437   if (!Subtarget->inMips16Mode()) {
438     TS.emitDirectiveSetNoReorder();
439     TS.emitDirectiveSetNoMacro();
440     TS.emitDirectiveSetNoAt();
441   }
442 }
443 
444 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
445 /// the last basic block in the function.
446 void MipsAsmPrinter::emitFunctionBodyEnd() {
447   MipsTargetStreamer &TS = getTargetStreamer();
448 
449   // There are instruction for this macros, but they must
450   // always be at the function end, and we can't emit and
451   // break with BB logic.
452   if (!Subtarget->inMips16Mode()) {
453     TS.emitDirectiveSetAt();
454     TS.emitDirectiveSetMacro();
455     TS.emitDirectiveSetReorder();
456   }
457   TS.emitDirectiveEnd(CurrentFnSym->getName());
458   // Make sure to terminate any constant pools that were at the end
459   // of the function.
460   if (!InConstantPool)
461     return;
462   InConstantPool = false;
463   OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
464 }
465 
466 void MipsAsmPrinter::emitBasicBlockEnd(const MachineBasicBlock &MBB) {
467   AsmPrinter::emitBasicBlockEnd(MBB);
468   MipsTargetStreamer &TS = getTargetStreamer();
469   if (MBB.empty())
470     TS.emitDirectiveInsn();
471 }
472 
473 // Print out an operand for an inline asm expression.
474 bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
475                                      const char *ExtraCode, raw_ostream &O) {
476   // Does this asm operand have a single letter operand modifier?
477   if (ExtraCode && ExtraCode[0]) {
478     if (ExtraCode[1] != 0) return true; // Unknown modifier.
479 
480     const MachineOperand &MO = MI->getOperand(OpNum);
481     switch (ExtraCode[0]) {
482     default:
483       // See if this is a generic print operand
484       return AsmPrinter::PrintAsmOperand(MI, OpNum, ExtraCode, O);
485     case 'X': // hex const int
486       if (!MO.isImm())
487         return true;
488       O << "0x" << Twine::utohexstr(MO.getImm());
489       return false;
490     case 'x': // hex const int (low 16 bits)
491       if (!MO.isImm())
492         return true;
493       O << "0x" << Twine::utohexstr(MO.getImm() & 0xffff);
494       return false;
495     case 'd': // decimal const int
496       if (!MO.isImm())
497         return true;
498       O << MO.getImm();
499       return false;
500     case 'm': // decimal const int minus 1
501       if (!MO.isImm())
502         return true;
503       O << MO.getImm() - 1;
504       return false;
505     case 'y': // exact log2
506       if (!MO.isImm())
507         return true;
508       if (!isPowerOf2_64(MO.getImm()))
509         return true;
510       O << Log2_64(MO.getImm());
511       return false;
512     case 'z':
513       // $0 if zero, regular printing otherwise
514       if (MO.isImm() && MO.getImm() == 0) {
515         O << "$0";
516         return false;
517       }
518       // If not, call printOperand as normal.
519       break;
520     case 'D': // Second part of a double word register operand
521     case 'L': // Low order register of a double word register operand
522     case 'M': // High order register of a double word register operand
523     {
524       if (OpNum == 0)
525         return true;
526       const MachineOperand &FlagsOP = MI->getOperand(OpNum - 1);
527       if (!FlagsOP.isImm())
528         return true;
529       const InlineAsm::Flag Flags(FlagsOP.getImm());
530       const unsigned NumVals = Flags.getNumOperandRegisters();
531       // Number of registers represented by this operand. We are looking
532       // for 2 for 32 bit mode and 1 for 64 bit mode.
533       if (NumVals != 2) {
534         if (Subtarget->isGP64bit() && NumVals == 1 && MO.isReg()) {
535           Register Reg = MO.getReg();
536           O << '$' << MipsInstPrinter::getRegisterName(Reg);
537           return false;
538         }
539         return true;
540       }
541 
542       unsigned RegOp = OpNum;
543       if (!Subtarget->isGP64bit()){
544         // Endianness reverses which register holds the high or low value
545         // between M and L.
546         switch(ExtraCode[0]) {
547         case 'M':
548           RegOp = (Subtarget->isLittle()) ? OpNum + 1 : OpNum;
549           break;
550         case 'L':
551           RegOp = (Subtarget->isLittle()) ? OpNum : OpNum + 1;
552           break;
553         case 'D': // Always the second part
554           RegOp = OpNum + 1;
555         }
556         if (RegOp >= MI->getNumOperands())
557           return true;
558         const MachineOperand &MO = MI->getOperand(RegOp);
559         if (!MO.isReg())
560           return true;
561         Register Reg = MO.getReg();
562         O << '$' << MipsInstPrinter::getRegisterName(Reg);
563         return false;
564       }
565       break;
566     }
567     case 'w': {
568       MCRegister w = getMSARegFromFReg(MO.getReg());
569       if (w != Mips::NoRegister) {
570         O << '$' << MipsInstPrinter::getRegisterName(w);
571         return false;
572       }
573       break;
574     }
575     }
576   }
577 
578   printOperand(MI, OpNum, O);
579   return false;
580 }
581 
582 bool MipsAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
583                                            unsigned OpNum,
584                                            const char *ExtraCode,
585                                            raw_ostream &O) {
586   assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands");
587   const MachineOperand &BaseMO = MI->getOperand(OpNum);
588   const MachineOperand &OffsetMO = MI->getOperand(OpNum + 1);
589   assert(BaseMO.isReg() &&
590          "Unexpected base pointer for inline asm memory operand.");
591   assert(OffsetMO.isImm() &&
592          "Unexpected offset for inline asm memory operand.");
593   int Offset = OffsetMO.getImm();
594 
595   // Currently we are expecting either no ExtraCode or 'D','M','L'.
596   if (ExtraCode) {
597     switch (ExtraCode[0]) {
598     case 'D':
599       Offset += 4;
600       break;
601     case 'M':
602       if (Subtarget->isLittle())
603         Offset += 4;
604       break;
605     case 'L':
606       if (!Subtarget->isLittle())
607         Offset += 4;
608       break;
609     default:
610       return true; // Unknown modifier.
611     }
612   }
613 
614   O << Offset << "($" << MipsInstPrinter::getRegisterName(BaseMO.getReg())
615     << ")";
616 
617   return false;
618 }
619 
620 void MipsAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
621                                   raw_ostream &O) {
622   const MachineOperand &MO = MI->getOperand(opNum);
623   bool closeP = false;
624 
625   if (MO.getTargetFlags())
626     closeP = true;
627 
628   switch(MO.getTargetFlags()) {
629   case MipsII::MO_GPREL:    O << "%gp_rel("; break;
630   case MipsII::MO_GOT_CALL: O << "%call16("; break;
631   case MipsII::MO_GOT:      O << "%got(";    break;
632   case MipsII::MO_ABS_HI:   O << "%hi(";     break;
633   case MipsII::MO_ABS_LO:   O << "%lo(";     break;
634   case MipsII::MO_HIGHER:   O << "%higher("; break;
635   case MipsII::MO_HIGHEST:  O << "%highest(("; break;
636   case MipsII::MO_TLSGD:    O << "%tlsgd(";  break;
637   case MipsII::MO_GOTTPREL: O << "%gottprel("; break;
638   case MipsII::MO_TPREL_HI: O << "%tprel_hi("; break;
639   case MipsII::MO_TPREL_LO: O << "%tprel_lo("; break;
640   case MipsII::MO_GPOFF_HI: O << "%hi(%neg(%gp_rel("; break;
641   case MipsII::MO_GPOFF_LO: O << "%lo(%neg(%gp_rel("; break;
642   case MipsII::MO_GOT_DISP: O << "%got_disp("; break;
643   case MipsII::MO_GOT_PAGE: O << "%got_page("; break;
644   case MipsII::MO_GOT_OFST: O << "%got_ofst("; break;
645   }
646 
647   switch (MO.getType()) {
648     case MachineOperand::MO_Register:
649       O << '$'
650         << StringRef(MipsInstPrinter::getRegisterName(MO.getReg())).lower();
651       break;
652 
653     case MachineOperand::MO_Immediate:
654       O << MO.getImm();
655       break;
656 
657     case MachineOperand::MO_MachineBasicBlock:
658       MO.getMBB()->getSymbol()->print(O, MAI);
659       return;
660 
661     case MachineOperand::MO_GlobalAddress:
662       PrintSymbolOperand(MO, O);
663       break;
664 
665     case MachineOperand::MO_BlockAddress: {
666       MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
667       O << BA->getName();
668       break;
669     }
670 
671     case MachineOperand::MO_ConstantPoolIndex:
672       O << getDataLayout().getPrivateGlobalPrefix() << "CPI"
673         << getFunctionNumber() << "_" << MO.getIndex();
674       if (MO.getOffset())
675         O << "+" << MO.getOffset();
676       break;
677 
678     default:
679       llvm_unreachable("<unknown operand type>");
680   }
681 
682   if (closeP) O << ")";
683 }
684 
685 void MipsAsmPrinter::
686 printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O) {
687   // Load/Store memory operands -- imm($reg)
688   // If PIC target the target is loaded as the
689   // pattern lw $25,%call16($28)
690 
691   // opNum can be invalid if instruction has reglist as operand.
692   // MemOperand is always last operand of instruction (base + offset).
693   switch (MI->getOpcode()) {
694   default:
695     break;
696   case Mips::SWM32_MM:
697   case Mips::LWM32_MM:
698     opNum = MI->getNumOperands() - 2;
699     break;
700   }
701 
702   printOperand(MI, opNum+1, O);
703   O << "(";
704   printOperand(MI, opNum, O);
705   O << ")";
706 }
707 
708 void MipsAsmPrinter::
709 printMemOperandEA(const MachineInstr *MI, int opNum, raw_ostream &O) {
710   // when using stack locations for not load/store instructions
711   // print the same way as all normal 3 operand instructions.
712   printOperand(MI, opNum, O);
713   O << ", ";
714   printOperand(MI, opNum+1, O);
715 }
716 
717 void MipsAsmPrinter::
718 printFCCOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
719                 const char *Modifier) {
720   const MachineOperand &MO = MI->getOperand(opNum);
721   O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm());
722 }
723 
724 void MipsAsmPrinter::
725 printRegisterList(const MachineInstr *MI, int opNum, raw_ostream &O) {
726   for (int i = opNum, e = MI->getNumOperands(); i != e; ++i) {
727     if (i != opNum) O << ", ";
728     printOperand(MI, i, O);
729   }
730 }
731 
732 void MipsAsmPrinter::emitStartOfAsmFile(Module &M) {
733   const Triple &TT = TM.getTargetTriple();
734 
735   if (TT.isOSBinFormatELF()) {
736     MipsTargetStreamer &TS = getTargetStreamer();
737 
738     // MipsTargetStreamer has an initialization order problem when emitting an
739     // object file directly (see MipsTargetELFStreamer for full details). Work
740     // around it by re-initializing the PIC state here.
741     TS.setPic(OutContext.getObjectFileInfo()->isPositionIndependent());
742 
743     // Try to get target-features from the first function.
744     StringRef FS = TM.getTargetFeatureString();
745     Module::iterator F = M.begin();
746     if (FS.empty() && M.size() && F->hasFnAttribute("target-features"))
747       FS = F->getFnAttribute("target-features").getValueAsString();
748 
749     // Compute MIPS architecture attributes based on the default subtarget
750     // that we'd have constructed.
751     // FIXME: For ifunc related functions we could iterate over and look
752     // for a feature string that doesn't match the default one.
753     StringRef CPU = MIPS_MC::selectMipsCPU(TT, TM.getTargetCPU());
754     const MipsTargetMachine &MTM = static_cast<const MipsTargetMachine &>(TM);
755     const MipsSubtarget STI(TT, CPU, FS, MTM.isLittleEndian(), MTM,
756                             std::nullopt);
757 
758     bool IsABICalls = STI.isABICalls();
759     const MipsABIInfo &ABI = MTM.getABI();
760     if (IsABICalls) {
761       TS.emitDirectiveAbiCalls();
762       // FIXME: This condition should be a lot more complicated that it is here.
763       //        Ideally it should test for properties of the ABI and not the ABI
764       //        itself.
765       //        For the moment, I'm only correcting enough to make MIPS-IV work.
766       if (!isPositionIndependent() && STI.hasSym32())
767         TS.emitDirectiveOptionPic0();
768     }
769 
770     // Tell the assembler which ABI we are using
771     std::string SectionName = std::string(".mdebug.") + getCurrentABIString();
772     OutStreamer->switchSection(
773         OutContext.getELFSection(SectionName, ELF::SHT_PROGBITS, 0));
774 
775     // NaN: At the moment we only support:
776     // 1. .nan legacy (default)
777     // 2. .nan 2008
778     STI.isNaN2008() ? TS.emitDirectiveNaN2008() : TS.emitDirectiveNaNLegacy();
779 
780     // TODO: handle O64 ABI
781 
782     TS.updateABIInfo(STI);
783 
784     // We should always emit a '.module fp=...' but binutils 2.24 does not
785     // accept it. We therefore emit it when it contradicts the ABI defaults
786     // (-mfpxx or -mfp64) and omit it otherwise.
787     if ((ABI.IsO32() && (STI.isABI_FPXX() || STI.isFP64bit())) ||
788         STI.useSoftFloat())
789       TS.emitDirectiveModuleFP();
790 
791     // We should always emit a '.module [no]oddspreg' but binutils 2.24 does not
792     // accept it. We therefore emit it when it contradicts the default or an
793     // option has changed the default (i.e. FPXX) and omit it otherwise.
794     if (ABI.IsO32() && (!STI.useOddSPReg() || STI.isABI_FPXX()))
795       TS.emitDirectiveModuleOddSPReg();
796 
797     // Switch to the .text section.
798     OutStreamer->switchSection(getObjFileLowering().getTextSection());
799   }
800 }
801 
802 void MipsAsmPrinter::emitInlineAsmStart() const {
803   MipsTargetStreamer &TS = getTargetStreamer();
804 
805   // GCC's choice of assembler options for inline assembly code ('at', 'macro'
806   // and 'reorder') is different from LLVM's choice for generated code ('noat',
807   // 'nomacro' and 'noreorder').
808   // In order to maintain compatibility with inline assembly code which depends
809   // on GCC's assembler options being used, we have to switch to those options
810   // for the duration of the inline assembly block and then switch back.
811   TS.emitDirectiveSetPush();
812   TS.emitDirectiveSetAt();
813   TS.emitDirectiveSetMacro();
814   TS.emitDirectiveSetReorder();
815   OutStreamer->addBlankLine();
816 }
817 
818 void MipsAsmPrinter::emitInlineAsmEnd(const MCSubtargetInfo &StartInfo,
819                                       const MCSubtargetInfo *EndInfo) const {
820   OutStreamer->addBlankLine();
821   getTargetStreamer().emitDirectiveSetPop();
822 }
823 
824 void MipsAsmPrinter::EmitJal(const MCSubtargetInfo &STI, MCSymbol *Symbol) {
825   MCInst I;
826   I.setOpcode(Mips::JAL);
827   I.addOperand(
828       MCOperand::createExpr(MCSymbolRefExpr::create(Symbol, OutContext)));
829   OutStreamer->emitInstruction(I, STI);
830 }
831 
832 void MipsAsmPrinter::EmitInstrReg(const MCSubtargetInfo &STI, unsigned Opcode,
833                                   unsigned Reg) {
834   MCInst I;
835   I.setOpcode(Opcode);
836   I.addOperand(MCOperand::createReg(Reg));
837   OutStreamer->emitInstruction(I, STI);
838 }
839 
840 void MipsAsmPrinter::EmitInstrRegReg(const MCSubtargetInfo &STI,
841                                      unsigned Opcode, unsigned Reg1,
842                                      unsigned Reg2) {
843   MCInst I;
844   //
845   // Because of the current td files for Mips32, the operands for MTC1
846   // appear backwards from their normal assembly order. It's not a trivial
847   // change to fix this in the td file so we adjust for it here.
848   //
849   if (Opcode == Mips::MTC1) {
850     unsigned Temp = Reg1;
851     Reg1 = Reg2;
852     Reg2 = Temp;
853   }
854   I.setOpcode(Opcode);
855   I.addOperand(MCOperand::createReg(Reg1));
856   I.addOperand(MCOperand::createReg(Reg2));
857   OutStreamer->emitInstruction(I, STI);
858 }
859 
860 void MipsAsmPrinter::EmitInstrRegRegReg(const MCSubtargetInfo &STI,
861                                         unsigned Opcode, unsigned Reg1,
862                                         unsigned Reg2, unsigned Reg3) {
863   MCInst I;
864   I.setOpcode(Opcode);
865   I.addOperand(MCOperand::createReg(Reg1));
866   I.addOperand(MCOperand::createReg(Reg2));
867   I.addOperand(MCOperand::createReg(Reg3));
868   OutStreamer->emitInstruction(I, STI);
869 }
870 
871 void MipsAsmPrinter::EmitMovFPIntPair(const MCSubtargetInfo &STI,
872                                       unsigned MovOpc, unsigned Reg1,
873                                       unsigned Reg2, unsigned FPReg1,
874                                       unsigned FPReg2, bool LE) {
875   if (!LE) {
876     unsigned temp = Reg1;
877     Reg1 = Reg2;
878     Reg2 = temp;
879   }
880   EmitInstrRegReg(STI, MovOpc, Reg1, FPReg1);
881   EmitInstrRegReg(STI, MovOpc, Reg2, FPReg2);
882 }
883 
884 void MipsAsmPrinter::EmitSwapFPIntParams(const MCSubtargetInfo &STI,
885                                          Mips16HardFloatInfo::FPParamVariant PV,
886                                          bool LE, bool ToFP) {
887   using namespace Mips16HardFloatInfo;
888 
889   unsigned MovOpc = ToFP ? Mips::MTC1 : Mips::MFC1;
890   switch (PV) {
891   case FSig:
892     EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12);
893     break;
894   case FFSig:
895     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F14, LE);
896     break;
897   case FDSig:
898     EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12);
899     EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE);
900     break;
901   case DSig:
902     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
903     break;
904   case DDSig:
905     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
906     EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE);
907     break;
908   case DFSig:
909     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
910     EmitInstrRegReg(STI, MovOpc, Mips::A2, Mips::F14);
911     break;
912   case NoSig:
913     return;
914   }
915 }
916 
917 void MipsAsmPrinter::EmitSwapFPIntRetval(
918     const MCSubtargetInfo &STI, Mips16HardFloatInfo::FPReturnVariant RV,
919     bool LE) {
920   using namespace Mips16HardFloatInfo;
921 
922   unsigned MovOpc = Mips::MFC1;
923   switch (RV) {
924   case FRet:
925     EmitInstrRegReg(STI, MovOpc, Mips::V0, Mips::F0);
926     break;
927   case DRet:
928     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
929     break;
930   case CFRet:
931     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
932     break;
933   case CDRet:
934     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
935     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F2, Mips::F3, LE);
936     break;
937   case NoFPRet:
938     break;
939   }
940 }
941 
942 void MipsAsmPrinter::EmitFPCallStub(
943     const char *Symbol, const Mips16HardFloatInfo::FuncSignature *Signature) {
944   using namespace Mips16HardFloatInfo;
945 
946   MCSymbol *MSymbol = OutContext.getOrCreateSymbol(StringRef(Symbol));
947   bool LE = getDataLayout().isLittleEndian();
948   // Construct a local MCSubtargetInfo here.
949   // This is because the MachineFunction won't exist (but have not yet been
950   // freed) and since we're at the global level we can use the default
951   // constructed subtarget.
952   std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
953       TM.getTargetTriple().str(), TM.getTargetCPU(),
954       TM.getTargetFeatureString()));
955 
956   //
957   // .global xxxx
958   //
959   OutStreamer->emitSymbolAttribute(MSymbol, MCSA_Global);
960   const char *RetType;
961   //
962   // make the comment field identifying the return and parameter
963   // types of the floating point stub
964   // # Stub function to call rettype xxxx (params)
965   //
966   switch (Signature->RetSig) {
967   case FRet:
968     RetType = "float";
969     break;
970   case DRet:
971     RetType = "double";
972     break;
973   case CFRet:
974     RetType = "complex";
975     break;
976   case CDRet:
977     RetType = "double complex";
978     break;
979   case NoFPRet:
980     RetType = "";
981     break;
982   }
983   const char *Parms;
984   switch (Signature->ParamSig) {
985   case FSig:
986     Parms = "float";
987     break;
988   case FFSig:
989     Parms = "float, float";
990     break;
991   case FDSig:
992     Parms = "float, double";
993     break;
994   case DSig:
995     Parms = "double";
996     break;
997   case DDSig:
998     Parms = "double, double";
999     break;
1000   case DFSig:
1001     Parms = "double, float";
1002     break;
1003   case NoSig:
1004     Parms = "";
1005     break;
1006   }
1007   OutStreamer->AddComment("\t# Stub function to call " + Twine(RetType) + " " +
1008                           Twine(Symbol) + " (" + Twine(Parms) + ")");
1009   //
1010   // probably not necessary but we save and restore the current section state
1011   //
1012   OutStreamer->pushSection();
1013   //
1014   // .section mips16.call.fpxxxx,"ax",@progbits
1015   //
1016   MCSectionELF *M = OutContext.getELFSection(
1017       ".mips16.call.fp." + std::string(Symbol), ELF::SHT_PROGBITS,
1018       ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
1019   OutStreamer->switchSection(M);
1020   //
1021   // .align 2
1022   //
1023   OutStreamer->emitValueToAlignment(Align(4));
1024   MipsTargetStreamer &TS = getTargetStreamer();
1025   //
1026   // .set nomips16
1027   // .set nomicromips
1028   //
1029   TS.emitDirectiveSetNoMips16();
1030   TS.emitDirectiveSetNoMicroMips();
1031   //
1032   // .ent __call_stub_fp_xxxx
1033   // .type  __call_stub_fp_xxxx,@function
1034   //  __call_stub_fp_xxxx:
1035   //
1036   std::string x = "__call_stub_fp_" + std::string(Symbol);
1037   MCSymbolELF *Stub =
1038       cast<MCSymbolELF>(OutContext.getOrCreateSymbol(StringRef(x)));
1039   TS.emitDirectiveEnt(*Stub);
1040   MCSymbol *MType =
1041       OutContext.getOrCreateSymbol("__call_stub_fp_" + Twine(Symbol));
1042   OutStreamer->emitSymbolAttribute(MType, MCSA_ELF_TypeFunction);
1043   OutStreamer->emitLabel(Stub);
1044 
1045   // Only handle non-pic for now.
1046   assert(!isPositionIndependent() &&
1047          "should not be here if we are compiling pic");
1048   TS.emitDirectiveSetReorder();
1049   //
1050   // We need to add a MipsMCExpr class to MCTargetDesc to fully implement
1051   // stubs without raw text but this current patch is for compiler generated
1052   // functions and they all return some value.
1053   // The calling sequence for non pic is different in that case and we need
1054   // to implement %lo and %hi in order to handle the case of no return value
1055   // See the corresponding method in Mips16HardFloat for details.
1056   //
1057   // mov the return address to S2.
1058   // we have no stack space to store it and we are about to make another call.
1059   // We need to make sure that the enclosing function knows to save S2
1060   // This should have already been handled.
1061   //
1062   // Mov $18, $31
1063 
1064   EmitInstrRegRegReg(*STI, Mips::OR, Mips::S2, Mips::RA, Mips::ZERO);
1065 
1066   EmitSwapFPIntParams(*STI, Signature->ParamSig, LE, true);
1067 
1068   // Jal xxxx
1069   //
1070   EmitJal(*STI, MSymbol);
1071 
1072   // fix return values
1073   EmitSwapFPIntRetval(*STI, Signature->RetSig, LE);
1074   //
1075   // do the return
1076   // if (Signature->RetSig == NoFPRet)
1077   //  llvm_unreachable("should not be any stubs here with no return value");
1078   // else
1079   EmitInstrReg(*STI, Mips::JR, Mips::S2);
1080 
1081   MCSymbol *Tmp = OutContext.createTempSymbol();
1082   OutStreamer->emitLabel(Tmp);
1083   const MCSymbolRefExpr *E = MCSymbolRefExpr::create(Stub, OutContext);
1084   const MCSymbolRefExpr *T = MCSymbolRefExpr::create(Tmp, OutContext);
1085   const MCExpr *T_min_E = MCBinaryExpr::createSub(T, E, OutContext);
1086   OutStreamer->emitELFSize(Stub, T_min_E);
1087   TS.emitDirectiveEnd(x);
1088   OutStreamer->popSection();
1089 }
1090 
1091 void MipsAsmPrinter::emitEndOfAsmFile(Module &M) {
1092   // Emit needed stubs
1093   //
1094   for (std::map<
1095            const char *,
1096            const Mips16HardFloatInfo::FuncSignature *>::const_iterator
1097            it = StubsNeeded.begin();
1098        it != StubsNeeded.end(); ++it) {
1099     const char *Symbol = it->first;
1100     const Mips16HardFloatInfo::FuncSignature *Signature = it->second;
1101     EmitFPCallStub(Symbol, Signature);
1102   }
1103   // return to the text section
1104   OutStreamer->switchSection(OutContext.getObjectFileInfo()->getTextSection());
1105 }
1106 
1107 void MipsAsmPrinter::EmitSled(const MachineInstr &MI, SledKind Kind) {
1108   const uint8_t NoopsInSledCount = Subtarget->isGP64bit() ? 15 : 11;
1109   // For mips32 we want to emit the following pattern:
1110   //
1111   // .Lxray_sled_N:
1112   //   ALIGN
1113   //   B .tmpN
1114   //   11 NOP instructions (44 bytes)
1115   //   ADDIU T9, T9, 52
1116   // .tmpN
1117   //
1118   // We need the 44 bytes (11 instructions) because at runtime, we'd
1119   // be patching over the full 48 bytes (12 instructions) with the following
1120   // pattern:
1121   //
1122   //   ADDIU    SP, SP, -8
1123   //   NOP
1124   //   SW       RA, 4(SP)
1125   //   SW       T9, 0(SP)
1126   //   LUI      T9, %hi(__xray_FunctionEntry/Exit)
1127   //   ORI      T9, T9, %lo(__xray_FunctionEntry/Exit)
1128   //   LUI      T0, %hi(function_id)
1129   //   JALR     T9
1130   //   ORI      T0, T0, %lo(function_id)
1131   //   LW       T9, 0(SP)
1132   //   LW       RA, 4(SP)
1133   //   ADDIU    SP, SP, 8
1134   //
1135   // We add 52 bytes to t9 because we want to adjust the function pointer to
1136   // the actual start of function i.e. the address just after the noop sled.
1137   // We do this because gp displacement relocation is emitted at the start of
1138   // of the function i.e after the nop sled and to correctly calculate the
1139   // global offset table address, t9 must hold the address of the instruction
1140   // containing the gp displacement relocation.
1141   // FIXME: Is this correct for the static relocation model?
1142   //
1143   // For mips64 we want to emit the following pattern:
1144   //
1145   // .Lxray_sled_N:
1146   //   ALIGN
1147   //   B .tmpN
1148   //   15 NOP instructions (60 bytes)
1149   // .tmpN
1150   //
1151   // We need the 60 bytes (15 instructions) because at runtime, we'd
1152   // be patching over the full 64 bytes (16 instructions) with the following
1153   // pattern:
1154   //
1155   //   DADDIU   SP, SP, -16
1156   //   NOP
1157   //   SD       RA, 8(SP)
1158   //   SD       T9, 0(SP)
1159   //   LUI      T9, %highest(__xray_FunctionEntry/Exit)
1160   //   ORI      T9, T9, %higher(__xray_FunctionEntry/Exit)
1161   //   DSLL     T9, T9, 16
1162   //   ORI      T9, T9, %hi(__xray_FunctionEntry/Exit)
1163   //   DSLL     T9, T9, 16
1164   //   ORI      T9, T9, %lo(__xray_FunctionEntry/Exit)
1165   //   LUI      T0, %hi(function_id)
1166   //   JALR     T9
1167   //   ADDIU    T0, T0, %lo(function_id)
1168   //   LD       T9, 0(SP)
1169   //   LD       RA, 8(SP)
1170   //   DADDIU   SP, SP, 16
1171   //
1172   OutStreamer->emitCodeAlignment(Align(4), &getSubtargetInfo());
1173   auto CurSled = OutContext.createTempSymbol("xray_sled_", true);
1174   OutStreamer->emitLabel(CurSled);
1175   auto Target = OutContext.createTempSymbol();
1176 
1177   // Emit "B .tmpN" instruction, which jumps over the nop sled to the actual
1178   // start of function
1179   const MCExpr *TargetExpr = MCSymbolRefExpr::create(
1180       Target, MCSymbolRefExpr::VariantKind::VK_None, OutContext);
1181   EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::BEQ)
1182                                    .addReg(Mips::ZERO)
1183                                    .addReg(Mips::ZERO)
1184                                    .addExpr(TargetExpr));
1185 
1186   for (int8_t I = 0; I < NoopsInSledCount; I++)
1187     EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::SLL)
1188                                      .addReg(Mips::ZERO)
1189                                      .addReg(Mips::ZERO)
1190                                      .addImm(0));
1191 
1192   OutStreamer->emitLabel(Target);
1193 
1194   if (!Subtarget->isGP64bit()) {
1195     EmitToStreamer(*OutStreamer,
1196                    MCInstBuilder(Mips::ADDiu)
1197                        .addReg(Mips::T9)
1198                        .addReg(Mips::T9)
1199                        .addImm(0x34));
1200   }
1201 
1202   recordSled(CurSled, MI, Kind, 2);
1203 }
1204 
1205 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI) {
1206   EmitSled(MI, SledKind::FUNCTION_ENTER);
1207 }
1208 
1209 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI) {
1210   EmitSled(MI, SledKind::FUNCTION_EXIT);
1211 }
1212 
1213 void MipsAsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI) {
1214   EmitSled(MI, SledKind::TAIL_CALL);
1215 }
1216 
1217 void MipsAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
1218                                            raw_ostream &OS) {
1219   // TODO: implement
1220 }
1221 
1222 // Emit .dtprelword or .dtpreldword directive
1223 // and value for debug thread local expression.
1224 void MipsAsmPrinter::emitDebugValue(const MCExpr *Value, unsigned Size) const {
1225   if (auto *MipsExpr = dyn_cast<MipsMCExpr>(Value)) {
1226     if (MipsExpr && MipsExpr->getKind() == MipsMCExpr::MEK_DTPREL) {
1227       switch (Size) {
1228       case 4:
1229         OutStreamer->emitDTPRel32Value(MipsExpr->getSubExpr());
1230         break;
1231       case 8:
1232         OutStreamer->emitDTPRel64Value(MipsExpr->getSubExpr());
1233         break;
1234       default:
1235         llvm_unreachable("Unexpected size of expression value.");
1236       }
1237       return;
1238     }
1239   }
1240   AsmPrinter::emitDebugValue(Value, Size);
1241 }
1242 
1243 // Align all targets of indirect branches on bundle size.  Used only if target
1244 // is NaCl.
1245 void MipsAsmPrinter::NaClAlignIndirectJumpTargets(MachineFunction &MF) {
1246   // Align all blocks that are jumped to through jump table.
1247   if (MachineJumpTableInfo *JtInfo = MF.getJumpTableInfo()) {
1248     const std::vector<MachineJumpTableEntry> &JT = JtInfo->getJumpTables();
1249     for (const auto &I : JT) {
1250       const std::vector<MachineBasicBlock *> &MBBs = I.MBBs;
1251 
1252       for (MachineBasicBlock *MBB : MBBs)
1253         MBB->setAlignment(MIPS_NACL_BUNDLE_ALIGN);
1254     }
1255   }
1256 
1257   // If basic block address is taken, block can be target of indirect branch.
1258   for (auto &MBB : MF) {
1259     if (MBB.hasAddressTaken())
1260       MBB.setAlignment(MIPS_NACL_BUNDLE_ALIGN);
1261   }
1262 }
1263 
1264 bool MipsAsmPrinter::isLongBranchPseudo(int Opcode) const {
1265   return (Opcode == Mips::LONG_BRANCH_LUi
1266           || Opcode == Mips::LONG_BRANCH_LUi2Op
1267           || Opcode == Mips::LONG_BRANCH_LUi2Op_64
1268           || Opcode == Mips::LONG_BRANCH_ADDiu
1269           || Opcode == Mips::LONG_BRANCH_ADDiu2Op
1270           || Opcode == Mips::LONG_BRANCH_DADDiu
1271           || Opcode == Mips::LONG_BRANCH_DADDiu2Op);
1272 }
1273 
1274 // Force static initialization.
1275 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeMipsAsmPrinter() {
1276   RegisterAsmPrinter<MipsAsmPrinter> X(getTheMipsTarget());
1277   RegisterAsmPrinter<MipsAsmPrinter> Y(getTheMipselTarget());
1278   RegisterAsmPrinter<MipsAsmPrinter> A(getTheMips64Target());
1279   RegisterAsmPrinter<MipsAsmPrinter> B(getTheMips64elTarget());
1280 }
1281