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