1 //===- MipsAsmPrinter.cpp - Mips LLVM Assembly Printer --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to GAS-format MIPS assembly language.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "MipsAsmPrinter.h"
16 #include "InstPrinter/MipsInstPrinter.h"
17 #include "MCTargetDesc/MipsABIInfo.h"
18 #include "MCTargetDesc/MipsBaseInfo.h"
19 #include "MCTargetDesc/MipsMCNaCl.h"
20 #include "MCTargetDesc/MipsMCTargetDesc.h"
21 #include "Mips.h"
22 #include "MipsMCInstLower.h"
23 #include "MipsMachineFunction.h"
24 #include "MipsSubtarget.h"
25 #include "MipsTargetMachine.h"
26 #include "MipsTargetStreamer.h"
27 #include "llvm/ADT/SmallString.h"
28 #include "llvm/ADT/StringRef.h"
29 #include "llvm/ADT/Triple.h"
30 #include "llvm/ADT/Twine.h"
31 #include "llvm/BinaryFormat/ELF.h"
32 #include "llvm/CodeGen/MachineBasicBlock.h"
33 #include "llvm/CodeGen/MachineConstantPool.h"
34 #include "llvm/CodeGen/MachineFrameInfo.h"
35 #include "llvm/CodeGen/MachineFunction.h"
36 #include "llvm/CodeGen/MachineInstr.h"
37 #include "llvm/CodeGen/MachineJumpTableInfo.h"
38 #include "llvm/CodeGen/MachineOperand.h"
39 #include "llvm/CodeGen/TargetRegisterInfo.h"
40 #include "llvm/CodeGen/TargetSubtargetInfo.h"
41 #include "llvm/IR/Attributes.h"
42 #include "llvm/IR/BasicBlock.h"
43 #include "llvm/IR/DataLayout.h"
44 #include "llvm/IR/Function.h"
45 #include "llvm/IR/InlineAsm.h"
46 #include "llvm/IR/Instructions.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/Support/Casting.h"
56 #include "llvm/Support/ErrorHandling.h"
57 #include "llvm/Support/TargetRegistry.h"
58 #include "llvm/Support/raw_ostream.h"
59 #include "llvm/Target/TargetMachine.h"
60 #include <cassert>
61 #include <cstdint>
62 #include <map>
63 #include <memory>
64 #include <string>
65 #include <vector>
66 
67 using namespace llvm;
68 
69 #define DEBUG_TYPE "mips-asm-printer"
70 
71 MipsTargetStreamer &MipsAsmPrinter::getTargetStreamer() const {
72   return static_cast<MipsTargetStreamer &>(*OutStreamer->getTargetStreamer());
73 }
74 
75 bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
76   Subtarget = &MF.getSubtarget<MipsSubtarget>();
77 
78   MipsFI = MF.getInfo<MipsFunctionInfo>();
79   if (Subtarget->inMips16Mode())
80     for (std::map<
81              const char *,
82              const Mips16HardFloatInfo::FuncSignature *>::const_iterator
83              it = MipsFI->StubsNeeded.begin();
84          it != MipsFI->StubsNeeded.end(); ++it) {
85       const char *Symbol = it->first;
86       const Mips16HardFloatInfo::FuncSignature *Signature = it->second;
87       if (StubsNeeded.find(Symbol) == StubsNeeded.end())
88         StubsNeeded[Symbol] = Signature;
89     }
90   MCP = MF.getConstantPool();
91 
92   // In NaCl, all indirect jump targets must be aligned to bundle size.
93   if (Subtarget->isTargetNaCl())
94     NaClAlignIndirectJumpTargets(MF);
95 
96   AsmPrinter::runOnMachineFunction(MF);
97 
98   emitXRayTable();
99 
100   return true;
101 }
102 
103 bool MipsAsmPrinter::lowerOperand(const MachineOperand &MO, MCOperand &MCOp) {
104   MCOp = MCInstLowering.LowerOperand(MO);
105   return MCOp.isValid();
106 }
107 
108 #include "MipsGenMCPseudoLowering.inc"
109 
110 // Lower PseudoReturn/PseudoIndirectBranch/PseudoIndirectBranch64 to JR, JR_MM,
111 // JALR, or JALR64 as appropriate for the target.
112 void MipsAsmPrinter::emitPseudoIndirectBranch(MCStreamer &OutStreamer,
113                                               const MachineInstr *MI) {
114   bool HasLinkReg = false;
115   bool InMicroMipsMode = Subtarget->inMicroMipsMode();
116   MCInst TmpInst0;
117 
118   if (Subtarget->hasMips64r6()) {
119     // MIPS64r6 should use (JALR64 ZERO_64, $rs)
120     TmpInst0.setOpcode(Mips::JALR64);
121     HasLinkReg = true;
122   } else if (Subtarget->hasMips32r6()) {
123     // MIPS32r6 should use (JALR ZERO, $rs)
124     if (InMicroMipsMode)
125       TmpInst0.setOpcode(Mips::JRC16_MMR6);
126     else {
127       TmpInst0.setOpcode(Mips::JALR);
128       HasLinkReg = true;
129     }
130   } else if (Subtarget->inMicroMipsMode())
131     // microMIPS should use (JR_MM $rs)
132     TmpInst0.setOpcode(Mips::JR_MM);
133   else {
134     // Everything else should use (JR $rs)
135     TmpInst0.setOpcode(Mips::JR);
136   }
137 
138   MCOperand MCOp;
139 
140   if (HasLinkReg) {
141     unsigned ZeroReg = Subtarget->isGP64bit() ? Mips::ZERO_64 : Mips::ZERO;
142     TmpInst0.addOperand(MCOperand::createReg(ZeroReg));
143   }
144 
145   lowerOperand(MI->getOperand(0), MCOp);
146   TmpInst0.addOperand(MCOp);
147 
148   EmitToStreamer(OutStreamer, TmpInst0);
149 }
150 
151 void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) {
152   MipsTargetStreamer &TS = getTargetStreamer();
153   unsigned Opc = MI->getOpcode();
154   TS.forbidModuleDirective();
155 
156   if (MI->isDebugValue()) {
157     SmallString<128> Str;
158     raw_svector_ostream OS(Str);
159 
160     PrintDebugValueComment(MI, OS);
161     return;
162   }
163   if (MI->isDebugLabel())
164     return;
165 
166   // If we just ended a constant pool, mark it as such.
167   if (InConstantPool && Opc != Mips::CONSTPOOL_ENTRY) {
168     OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
169     InConstantPool = false;
170   }
171   if (Opc == Mips::CONSTPOOL_ENTRY) {
172     // CONSTPOOL_ENTRY - This instruction represents a floating
173     // constant pool in the function.  The first operand is the ID#
174     // for this instruction, the second is the index into the
175     // MachineConstantPool that this is, the third is the size in
176     // bytes of this constant pool entry.
177     // The required alignment is specified on the basic block holding this MI.
178     //
179     unsigned LabelId = (unsigned)MI->getOperand(0).getImm();
180     unsigned CPIdx = (unsigned)MI->getOperand(1).getIndex();
181 
182     // If this is the first entry of the pool, mark it.
183     if (!InConstantPool) {
184       OutStreamer->EmitDataRegion(MCDR_DataRegion);
185       InConstantPool = true;
186     }
187 
188     OutStreamer->EmitLabel(GetCPISymbol(LabelId));
189 
190     const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx];
191     if (MCPE.isMachineConstantPoolEntry())
192       EmitMachineConstantPoolValue(MCPE.Val.MachineCPVal);
193     else
194       EmitGlobalConstant(MF->getDataLayout(), MCPE.Val.ConstVal);
195     return;
196   }
197 
198   switch (Opc) {
199   case Mips::PATCHABLE_FUNCTION_ENTER:
200     LowerPATCHABLE_FUNCTION_ENTER(*MI);
201     return;
202   case Mips::PATCHABLE_FUNCTION_EXIT:
203     LowerPATCHABLE_FUNCTION_EXIT(*MI);
204     return;
205   case Mips::PATCHABLE_TAIL_CALL:
206     LowerPATCHABLE_TAIL_CALL(*MI);
207     return;
208   }
209 
210   MachineBasicBlock::const_instr_iterator I = MI->getIterator();
211   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
212 
213   do {
214     // Do any auto-generated pseudo lowerings.
215     if (emitPseudoExpansionLowering(*OutStreamer, &*I))
216       continue;
217 
218     if (I->getOpcode() == Mips::PseudoReturn ||
219         I->getOpcode() == Mips::PseudoReturn64 ||
220         I->getOpcode() == Mips::PseudoIndirectBranch ||
221         I->getOpcode() == Mips::PseudoIndirectBranch64 ||
222         I->getOpcode() == Mips::TAILCALLREG ||
223         I->getOpcode() == Mips::TAILCALLREG64) {
224       emitPseudoIndirectBranch(*OutStreamer, &*I);
225       continue;
226     }
227 
228     // The inMips16Mode() test is not permanent.
229     // Some instructions are marked as pseudo right now which
230     // would make the test fail for the wrong reason but
231     // that will be fixed soon. We need this here because we are
232     // removing another test for this situation downstream in the
233     // callchain.
234     //
235     if (I->isPseudo() && !Subtarget->inMips16Mode()
236         && !isLongBranchPseudo(I->getOpcode()))
237       llvm_unreachable("Pseudo opcode found in EmitInstruction()");
238 
239     MCInst TmpInst0;
240     MCInstLowering.Lower(&*I, TmpInst0);
241     EmitToStreamer(*OutStreamer, TmpInst0);
242   } while ((++I != E) && I->isInsideBundle()); // Delay slot check
243 }
244 
245 //===----------------------------------------------------------------------===//
246 //
247 //  Mips Asm Directives
248 //
249 //  -- Frame directive "frame Stackpointer, Stacksize, RARegister"
250 //  Describe the stack frame.
251 //
252 //  -- Mask directives "(f)mask  bitmask, offset"
253 //  Tells the assembler which registers are saved and where.
254 //  bitmask - contain a little endian bitset indicating which registers are
255 //            saved on function prologue (e.g. with a 0x80000000 mask, the
256 //            assembler knows the register 31 (RA) is saved at prologue.
257 //  offset  - the position before stack pointer subtraction indicating where
258 //            the first saved register on prologue is located. (e.g. with a
259 //
260 //  Consider the following function prologue:
261 //
262 //    .frame  $fp,48,$ra
263 //    .mask   0xc0000000,-8
264 //       addiu $sp, $sp, -48
265 //       sw $ra, 40($sp)
266 //       sw $fp, 36($sp)
267 //
268 //    With a 0xc0000000 mask, the assembler knows the register 31 (RA) and
269 //    30 (FP) are saved at prologue. As the save order on prologue is from
270 //    left to right, RA is saved first. A -8 offset means that after the
271 //    stack pointer subtration, the first register in the mask (RA) will be
272 //    saved at address 48-8=40.
273 //
274 //===----------------------------------------------------------------------===//
275 
276 //===----------------------------------------------------------------------===//
277 // Mask directives
278 //===----------------------------------------------------------------------===//
279 
280 // Create a bitmask with all callee saved registers for CPU or Floating Point
281 // registers. For CPU registers consider RA, GP and FP for saving if necessary.
282 void MipsAsmPrinter::printSavedRegsBitmask() {
283   // CPU and FPU Saved Registers Bitmasks
284   unsigned CPUBitmask = 0, FPUBitmask = 0;
285   int CPUTopSavedRegOff, FPUTopSavedRegOff;
286 
287   // Set the CPU and FPU Bitmasks
288   const MachineFrameInfo &MFI = MF->getFrameInfo();
289   const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
290   const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
291   // size of stack area to which FP callee-saved regs are saved.
292   unsigned CPURegSize = TRI->getRegSizeInBits(Mips::GPR32RegClass) / 8;
293   unsigned FGR32RegSize = TRI->getRegSizeInBits(Mips::FGR32RegClass) / 8;
294   unsigned AFGR64RegSize = TRI->getRegSizeInBits(Mips::AFGR64RegClass) / 8;
295   bool HasAFGR64Reg = false;
296   unsigned CSFPRegsSize = 0;
297 
298   for (const auto &I : CSI) {
299     unsigned Reg = I.getReg();
300     unsigned RegNum = TRI->getEncodingValue(Reg);
301 
302     // If it's a floating point register, set the FPU Bitmask.
303     // If it's a general purpose register, set the CPU Bitmask.
304     if (Mips::FGR32RegClass.contains(Reg)) {
305       FPUBitmask |= (1 << RegNum);
306       CSFPRegsSize += FGR32RegSize;
307     } else if (Mips::AFGR64RegClass.contains(Reg)) {
308       FPUBitmask |= (3 << RegNum);
309       CSFPRegsSize += AFGR64RegSize;
310       HasAFGR64Reg = true;
311     } else if (Mips::GPR32RegClass.contains(Reg))
312       CPUBitmask |= (1 << RegNum);
313   }
314 
315   // FP Regs are saved right below where the virtual frame pointer points to.
316   FPUTopSavedRegOff = FPUBitmask ?
317     (HasAFGR64Reg ? -AFGR64RegSize : -FGR32RegSize) : 0;
318 
319   // CPU Regs are saved below FP Regs.
320   CPUTopSavedRegOff = CPUBitmask ? -CSFPRegsSize - CPURegSize : 0;
321 
322   MipsTargetStreamer &TS = getTargetStreamer();
323   // Print CPUBitmask
324   TS.emitMask(CPUBitmask, CPUTopSavedRegOff);
325 
326   // Print FPUBitmask
327   TS.emitFMask(FPUBitmask, FPUTopSavedRegOff);
328 }
329 
330 //===----------------------------------------------------------------------===//
331 // Frame and Set directives
332 //===----------------------------------------------------------------------===//
333 
334 /// Frame Directive
335 void MipsAsmPrinter::emitFrameDirective() {
336   const TargetRegisterInfo &RI = *MF->getSubtarget().getRegisterInfo();
337 
338   unsigned stackReg  = RI.getFrameRegister(*MF);
339   unsigned returnReg = RI.getRARegister();
340   unsigned stackSize = MF->getFrameInfo().getStackSize();
341 
342   getTargetStreamer().emitFrame(stackReg, stackSize, returnReg);
343 }
344 
345 /// Emit Set directives.
346 const char *MipsAsmPrinter::getCurrentABIString() const {
347   switch (static_cast<MipsTargetMachine &>(TM).getABI().GetEnumValue()) {
348   case MipsABIInfo::ABI::O32:  return "abi32";
349   case MipsABIInfo::ABI::N32:  return "abiN32";
350   case MipsABIInfo::ABI::N64:  return "abi64";
351   default: llvm_unreachable("Unknown Mips ABI");
352   }
353 }
354 
355 void MipsAsmPrinter::EmitFunctionEntryLabel() {
356   MipsTargetStreamer &TS = getTargetStreamer();
357 
358   // NaCl sandboxing requires that indirect call instructions are masked.
359   // This means that function entry points should be bundle-aligned.
360   if (Subtarget->isTargetNaCl())
361     EmitAlignment(std::max(MF->getAlignment(), MIPS_NACL_BUNDLE_ALIGN));
362 
363   if (Subtarget->inMicroMipsMode()) {
364     TS.emitDirectiveSetMicroMips();
365     TS.setUsesMicroMips();
366     TS.updateABIInfo(*Subtarget);
367   } else
368     TS.emitDirectiveSetNoMicroMips();
369 
370   if (Subtarget->inMips16Mode())
371     TS.emitDirectiveSetMips16();
372   else
373     TS.emitDirectiveSetNoMips16();
374 
375   TS.emitDirectiveEnt(*CurrentFnSym);
376   OutStreamer->EmitLabel(CurrentFnSym);
377 }
378 
379 /// EmitFunctionBodyStart - Targets can override this to emit stuff before
380 /// the first basic block in the function.
381 void MipsAsmPrinter::EmitFunctionBodyStart() {
382   MipsTargetStreamer &TS = getTargetStreamer();
383 
384   MCInstLowering.Initialize(&MF->getContext());
385 
386   bool IsNakedFunction = MF->getFunction().hasFnAttribute(Attribute::Naked);
387   if (!IsNakedFunction)
388     emitFrameDirective();
389 
390   if (!IsNakedFunction)
391     printSavedRegsBitmask();
392 
393   if (!Subtarget->inMips16Mode()) {
394     TS.emitDirectiveSetNoReorder();
395     TS.emitDirectiveSetNoMacro();
396     TS.emitDirectiveSetNoAt();
397   }
398 }
399 
400 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
401 /// the last basic block in the function.
402 void MipsAsmPrinter::EmitFunctionBodyEnd() {
403   MipsTargetStreamer &TS = getTargetStreamer();
404 
405   // There are instruction for this macros, but they must
406   // always be at the function end, and we can't emit and
407   // break with BB logic.
408   if (!Subtarget->inMips16Mode()) {
409     TS.emitDirectiveSetAt();
410     TS.emitDirectiveSetMacro();
411     TS.emitDirectiveSetReorder();
412   }
413   TS.emitDirectiveEnd(CurrentFnSym->getName());
414   // Make sure to terminate any constant pools that were at the end
415   // of the function.
416   if (!InConstantPool)
417     return;
418   InConstantPool = false;
419   OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
420 }
421 
422 void MipsAsmPrinter::EmitBasicBlockEnd(const MachineBasicBlock &MBB) {
423   AsmPrinter::EmitBasicBlockEnd(MBB);
424   MipsTargetStreamer &TS = getTargetStreamer();
425   if (MBB.empty())
426     TS.emitDirectiveInsn();
427 }
428 
429 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
430 /// exactly one predecessor and the control transfer mechanism between
431 /// the predecessor and this block is a fall-through.
432 bool MipsAsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock*
433                                                        MBB) const {
434   // The predecessor has to be immediately before this block.
435   const MachineBasicBlock *Pred = *MBB->pred_begin();
436 
437   // If the predecessor is a switch statement, assume a jump table
438   // implementation, so it is not a fall through.
439   if (const BasicBlock *bb = Pred->getBasicBlock())
440     if (isa<SwitchInst>(bb->getTerminator()))
441       return false;
442 
443   // If this is a landing pad, it isn't a fall through.  If it has no preds,
444   // then nothing falls through to it.
445   if (MBB->isEHPad() || MBB->pred_empty())
446     return false;
447 
448   // If there isn't exactly one predecessor, it can't be a fall through.
449   MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
450   ++PI2;
451 
452   if (PI2 != MBB->pred_end())
453     return false;
454 
455   // The predecessor has to be immediately before this block.
456   if (!Pred->isLayoutSuccessor(MBB))
457     return false;
458 
459   // If the block is completely empty, then it definitely does fall through.
460   if (Pred->empty())
461     return true;
462 
463   // Otherwise, check the last instruction.
464   // Check if the last terminator is an unconditional branch.
465   MachineBasicBlock::const_iterator I = Pred->end();
466   while (I != Pred->begin() && !(--I)->isTerminator()) ;
467 
468   return !I->isBarrier();
469 }
470 
471 // Print out an operand for an inline asm expression.
472 bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
473                                      unsigned AsmVariant, const char *ExtraCode,
474                                      raw_ostream &O) {
475   // Does this asm operand have a single letter operand modifier?
476   if (ExtraCode && ExtraCode[0]) {
477     if (ExtraCode[1] != 0) return true; // Unknown modifier.
478 
479     const MachineOperand &MO = MI->getOperand(OpNum);
480     switch (ExtraCode[0]) {
481     default:
482       // See if this is a generic print operand
483       return AsmPrinter::PrintAsmOperand(MI,OpNum,AsmVariant,ExtraCode,O);
484     case 'X': // hex const int
485       if ((MO.getType()) != MachineOperand::MO_Immediate)
486         return true;
487       O << "0x" << Twine::utohexstr(MO.getImm());
488       return false;
489     case 'x': // hex const int (low 16 bits)
490       if ((MO.getType()) != MachineOperand::MO_Immediate)
491         return true;
492       O << "0x" << Twine::utohexstr(MO.getImm() & 0xffff);
493       return false;
494     case 'd': // decimal const int
495       if ((MO.getType()) != MachineOperand::MO_Immediate)
496         return true;
497       O << MO.getImm();
498       return false;
499     case 'm': // decimal const int minus 1
500       if ((MO.getType()) != MachineOperand::MO_Immediate)
501         return true;
502       O << MO.getImm() - 1;
503       return false;
504     case 'y': // exact log2
505       if ((MO.getType()) != MachineOperand::MO_Immediate)
506         return true;
507       if (!isPowerOf2_64(MO.getImm()))
508         return true;
509       O << Log2_64(MO.getImm());
510       return false;
511     case 'z':
512       // $0 if zero, regular printing otherwise
513       if (MO.getType() == MachineOperand::MO_Immediate && MO.getImm() == 0) {
514         O << "$0";
515         return false;
516       }
517       // If not, call printOperand as normal.
518       break;
519     case 'D': // Second part of a double word register operand
520     case 'L': // Low order register of a double word register operand
521     case 'M': // High order register of a double word register operand
522     {
523       if (OpNum == 0)
524         return true;
525       const MachineOperand &FlagsOP = MI->getOperand(OpNum - 1);
526       if (!FlagsOP.isImm())
527         return true;
528       unsigned Flags = FlagsOP.getImm();
529       unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
530       // Number of registers represented by this operand. We are looking
531       // for 2 for 32 bit mode and 1 for 64 bit mode.
532       if (NumVals != 2) {
533         if (Subtarget->isGP64bit() && NumVals == 1 && MO.isReg()) {
534           unsigned Reg = MO.getReg();
535           O << '$' << MipsInstPrinter::getRegisterName(Reg);
536           return false;
537         }
538         return true;
539       }
540 
541       unsigned RegOp = OpNum;
542       if (!Subtarget->isGP64bit()){
543         // Endianness reverses which register holds the high or low value
544         // between M and L.
545         switch(ExtraCode[0]) {
546         case 'M':
547           RegOp = (Subtarget->isLittle()) ? OpNum + 1 : OpNum;
548           break;
549         case 'L':
550           RegOp = (Subtarget->isLittle()) ? OpNum : OpNum + 1;
551           break;
552         case 'D': // Always the second part
553           RegOp = OpNum + 1;
554         }
555         if (RegOp >= MI->getNumOperands())
556           return true;
557         const MachineOperand &MO = MI->getOperand(RegOp);
558         if (!MO.isReg())
559           return true;
560         unsigned Reg = MO.getReg();
561         O << '$' << MipsInstPrinter::getRegisterName(Reg);
562         return false;
563       }
564       break;
565     }
566     case 'w':
567       // Print MSA registers for the 'f' constraint
568       // In LLVM, the 'w' modifier doesn't need to do anything.
569       // We can just call printOperand as normal.
570       break;
571     }
572   }
573 
574   printOperand(MI, OpNum, O);
575   return false;
576 }
577 
578 bool MipsAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
579                                            unsigned OpNum, unsigned AsmVariant,
580                                            const char *ExtraCode,
581                                            raw_ostream &O) {
582   assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands");
583   const MachineOperand &BaseMO = MI->getOperand(OpNum);
584   const MachineOperand &OffsetMO = MI->getOperand(OpNum + 1);
585   assert(BaseMO.isReg() && "Unexpected base pointer for inline asm memory operand.");
586   assert(OffsetMO.isImm() && "Unexpected offset for inline asm memory operand.");
587   int Offset = OffsetMO.getImm();
588 
589   // Currently we are expecting either no ExtraCode or 'D','M','L'.
590   if (ExtraCode) {
591     switch (ExtraCode[0]) {
592     case 'D':
593       Offset += 4;
594       break;
595     case 'M':
596       if (Subtarget->isLittle())
597         Offset += 4;
598       break;
599     case 'L':
600       if (!Subtarget->isLittle())
601         Offset += 4;
602       break;
603     default:
604       return true; // Unknown modifier.
605     }
606   }
607 
608   O << Offset << "($" << MipsInstPrinter::getRegisterName(BaseMO.getReg())
609     << ")";
610 
611   return false;
612 }
613 
614 void MipsAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
615                                   raw_ostream &O) {
616   const MachineOperand &MO = MI->getOperand(opNum);
617   bool closeP = false;
618 
619   if (MO.getTargetFlags())
620     closeP = true;
621 
622   switch(MO.getTargetFlags()) {
623   case MipsII::MO_GPREL:    O << "%gp_rel("; break;
624   case MipsII::MO_GOT_CALL: O << "%call16("; break;
625   case MipsII::MO_GOT:      O << "%got(";    break;
626   case MipsII::MO_ABS_HI:   O << "%hi(";     break;
627   case MipsII::MO_ABS_LO:   O << "%lo(";     break;
628   case MipsII::MO_HIGHER:   O << "%higher("; break;
629   case MipsII::MO_HIGHEST:  O << "%highest(("; break;
630   case MipsII::MO_TLSGD:    O << "%tlsgd(";  break;
631   case MipsII::MO_GOTTPREL: O << "%gottprel("; break;
632   case MipsII::MO_TPREL_HI: O << "%tprel_hi("; break;
633   case MipsII::MO_TPREL_LO: O << "%tprel_lo("; break;
634   case MipsII::MO_GPOFF_HI: O << "%hi(%neg(%gp_rel("; break;
635   case MipsII::MO_GPOFF_LO: O << "%lo(%neg(%gp_rel("; break;
636   case MipsII::MO_GOT_DISP: O << "%got_disp("; break;
637   case MipsII::MO_GOT_PAGE: O << "%got_page("; break;
638   case MipsII::MO_GOT_OFST: O << "%got_ofst("; break;
639   }
640 
641   switch (MO.getType()) {
642     case MachineOperand::MO_Register:
643       O << '$'
644         << StringRef(MipsInstPrinter::getRegisterName(MO.getReg())).lower();
645       break;
646 
647     case MachineOperand::MO_Immediate:
648       O << MO.getImm();
649       break;
650 
651     case MachineOperand::MO_MachineBasicBlock:
652       MO.getMBB()->getSymbol()->print(O, MAI);
653       return;
654 
655     case MachineOperand::MO_GlobalAddress:
656       getSymbol(MO.getGlobal())->print(O, MAI);
657       break;
658 
659     case MachineOperand::MO_BlockAddress: {
660       MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
661       O << BA->getName();
662       break;
663     }
664 
665     case MachineOperand::MO_ConstantPoolIndex:
666       O << getDataLayout().getPrivateGlobalPrefix() << "CPI"
667         << getFunctionNumber() << "_" << MO.getIndex();
668       if (MO.getOffset())
669         O << "+" << MO.getOffset();
670       break;
671 
672     default:
673       llvm_unreachable("<unknown operand type>");
674   }
675 
676   if (closeP) O << ")";
677 }
678 
679 void MipsAsmPrinter::
680 printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O) {
681   // Load/Store memory operands -- imm($reg)
682   // If PIC target the target is loaded as the
683   // pattern lw $25,%call16($28)
684 
685   // opNum can be invalid if instruction has reglist as operand.
686   // MemOperand is always last operand of instruction (base + offset).
687   switch (MI->getOpcode()) {
688   default:
689     break;
690   case Mips::SWM32_MM:
691   case Mips::LWM32_MM:
692     opNum = MI->getNumOperands() - 2;
693     break;
694   }
695 
696   printOperand(MI, opNum+1, O);
697   O << "(";
698   printOperand(MI, opNum, O);
699   O << ")";
700 }
701 
702 void MipsAsmPrinter::
703 printMemOperandEA(const MachineInstr *MI, int opNum, raw_ostream &O) {
704   // when using stack locations for not load/store instructions
705   // print the same way as all normal 3 operand instructions.
706   printOperand(MI, opNum, O);
707   O << ", ";
708   printOperand(MI, opNum+1, O);
709 }
710 
711 void MipsAsmPrinter::
712 printFCCOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
713                 const char *Modifier) {
714   const MachineOperand &MO = MI->getOperand(opNum);
715   O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm());
716 }
717 
718 void MipsAsmPrinter::
719 printRegisterList(const MachineInstr *MI, int opNum, raw_ostream &O) {
720   for (int i = opNum, e = MI->getNumOperands(); i != e; ++i) {
721     if (i != opNum) O << ", ";
722     printOperand(MI, i, O);
723   }
724 }
725 
726 void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
727   MipsTargetStreamer &TS = getTargetStreamer();
728 
729   // MipsTargetStreamer has an initialization order problem when emitting an
730   // object file directly (see MipsTargetELFStreamer for full details). Work
731   // around it by re-initializing the PIC state here.
732   TS.setPic(OutContext.getObjectFileInfo()->isPositionIndependent());
733 
734   // Compute MIPS architecture attributes based on the default subtarget
735   // that we'd have constructed. Module level directives aren't LTO
736   // clean anyhow.
737   // FIXME: For ifunc related functions we could iterate over and look
738   // for a feature string that doesn't match the default one.
739   const Triple &TT = TM.getTargetTriple();
740   StringRef CPU = MIPS_MC::selectMipsCPU(TT, TM.getTargetCPU());
741   StringRef FS = TM.getTargetFeatureString();
742   const MipsTargetMachine &MTM = static_cast<const MipsTargetMachine &>(TM);
743   const MipsSubtarget STI(TT, CPU, FS, MTM.isLittleEndian(), MTM, 0);
744 
745   bool IsABICalls = STI.isABICalls();
746   const MipsABIInfo &ABI = MTM.getABI();
747   if (IsABICalls) {
748     TS.emitDirectiveAbiCalls();
749     // FIXME: This condition should be a lot more complicated that it is here.
750     //        Ideally it should test for properties of the ABI and not the ABI
751     //        itself.
752     //        For the moment, I'm only correcting enough to make MIPS-IV work.
753     if (!isPositionIndependent() && STI.hasSym32())
754       TS.emitDirectiveOptionPic0();
755   }
756 
757   // Tell the assembler which ABI we are using
758   std::string SectionName = std::string(".mdebug.") + getCurrentABIString();
759   OutStreamer->SwitchSection(
760       OutContext.getELFSection(SectionName, ELF::SHT_PROGBITS, 0));
761 
762   // NaN: At the moment we only support:
763   // 1. .nan legacy (default)
764   // 2. .nan 2008
765   STI.isNaN2008() ? TS.emitDirectiveNaN2008()
766                   : TS.emitDirectiveNaNLegacy();
767 
768   // TODO: handle O64 ABI
769 
770   TS.updateABIInfo(STI);
771 
772   // We should always emit a '.module fp=...' but binutils 2.24 does not accept
773   // it. We therefore emit it when it contradicts the ABI defaults (-mfpxx or
774   // -mfp64) and omit it otherwise.
775   if (ABI.IsO32() && (STI.isABI_FPXX() || STI.isFP64bit()))
776     TS.emitDirectiveModuleFP();
777 
778   // We should always emit a '.module [no]oddspreg' but binutils 2.24 does not
779   // accept it. We therefore emit it when it contradicts the default or an
780   // option has changed the default (i.e. FPXX) and omit it otherwise.
781   if (ABI.IsO32() && (!STI.useOddSPReg() || STI.isABI_FPXX()))
782     TS.emitDirectiveModuleOddSPReg();
783 }
784 
785 void MipsAsmPrinter::emitInlineAsmStart() const {
786   MipsTargetStreamer &TS = getTargetStreamer();
787 
788   // GCC's choice of assembler options for inline assembly code ('at', 'macro'
789   // and 'reorder') is different from LLVM's choice for generated code ('noat',
790   // 'nomacro' and 'noreorder').
791   // In order to maintain compatibility with inline assembly code which depends
792   // on GCC's assembler options being used, we have to switch to those options
793   // for the duration of the inline assembly block and then switch back.
794   TS.emitDirectiveSetPush();
795   TS.emitDirectiveSetAt();
796   TS.emitDirectiveSetMacro();
797   TS.emitDirectiveSetReorder();
798   OutStreamer->AddBlankLine();
799 }
800 
801 void MipsAsmPrinter::emitInlineAsmEnd(const MCSubtargetInfo &StartInfo,
802                                       const MCSubtargetInfo *EndInfo) const {
803   OutStreamer->AddBlankLine();
804   getTargetStreamer().emitDirectiveSetPop();
805 }
806 
807 void MipsAsmPrinter::EmitJal(const MCSubtargetInfo &STI, MCSymbol *Symbol) {
808   MCInst I;
809   I.setOpcode(Mips::JAL);
810   I.addOperand(
811       MCOperand::createExpr(MCSymbolRefExpr::create(Symbol, OutContext)));
812   OutStreamer->EmitInstruction(I, STI);
813 }
814 
815 void MipsAsmPrinter::EmitInstrReg(const MCSubtargetInfo &STI, unsigned Opcode,
816                                   unsigned Reg) {
817   MCInst I;
818   I.setOpcode(Opcode);
819   I.addOperand(MCOperand::createReg(Reg));
820   OutStreamer->EmitInstruction(I, STI);
821 }
822 
823 void MipsAsmPrinter::EmitInstrRegReg(const MCSubtargetInfo &STI,
824                                      unsigned Opcode, unsigned Reg1,
825                                      unsigned Reg2) {
826   MCInst I;
827   //
828   // Because of the current td files for Mips32, the operands for MTC1
829   // appear backwards from their normal assembly order. It's not a trivial
830   // change to fix this in the td file so we adjust for it here.
831   //
832   if (Opcode == Mips::MTC1) {
833     unsigned Temp = Reg1;
834     Reg1 = Reg2;
835     Reg2 = Temp;
836   }
837   I.setOpcode(Opcode);
838   I.addOperand(MCOperand::createReg(Reg1));
839   I.addOperand(MCOperand::createReg(Reg2));
840   OutStreamer->EmitInstruction(I, STI);
841 }
842 
843 void MipsAsmPrinter::EmitInstrRegRegReg(const MCSubtargetInfo &STI,
844                                         unsigned Opcode, unsigned Reg1,
845                                         unsigned Reg2, unsigned Reg3) {
846   MCInst I;
847   I.setOpcode(Opcode);
848   I.addOperand(MCOperand::createReg(Reg1));
849   I.addOperand(MCOperand::createReg(Reg2));
850   I.addOperand(MCOperand::createReg(Reg3));
851   OutStreamer->EmitInstruction(I, STI);
852 }
853 
854 void MipsAsmPrinter::EmitMovFPIntPair(const MCSubtargetInfo &STI,
855                                       unsigned MovOpc, unsigned Reg1,
856                                       unsigned Reg2, unsigned FPReg1,
857                                       unsigned FPReg2, bool LE) {
858   if (!LE) {
859     unsigned temp = Reg1;
860     Reg1 = Reg2;
861     Reg2 = temp;
862   }
863   EmitInstrRegReg(STI, MovOpc, Reg1, FPReg1);
864   EmitInstrRegReg(STI, MovOpc, Reg2, FPReg2);
865 }
866 
867 void MipsAsmPrinter::EmitSwapFPIntParams(const MCSubtargetInfo &STI,
868                                          Mips16HardFloatInfo::FPParamVariant PV,
869                                          bool LE, bool ToFP) {
870   using namespace Mips16HardFloatInfo;
871 
872   unsigned MovOpc = ToFP ? Mips::MTC1 : Mips::MFC1;
873   switch (PV) {
874   case FSig:
875     EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12);
876     break;
877   case FFSig:
878     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F14, LE);
879     break;
880   case FDSig:
881     EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12);
882     EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE);
883     break;
884   case DSig:
885     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
886     break;
887   case DDSig:
888     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
889     EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE);
890     break;
891   case DFSig:
892     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
893     EmitInstrRegReg(STI, MovOpc, Mips::A2, Mips::F14);
894     break;
895   case NoSig:
896     return;
897   }
898 }
899 
900 void MipsAsmPrinter::EmitSwapFPIntRetval(
901     const MCSubtargetInfo &STI, Mips16HardFloatInfo::FPReturnVariant RV,
902     bool LE) {
903   using namespace Mips16HardFloatInfo;
904 
905   unsigned MovOpc = Mips::MFC1;
906   switch (RV) {
907   case FRet:
908     EmitInstrRegReg(STI, MovOpc, Mips::V0, Mips::F0);
909     break;
910   case DRet:
911     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
912     break;
913   case CFRet:
914     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
915     break;
916   case CDRet:
917     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
918     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F2, Mips::F3, LE);
919     break;
920   case NoFPRet:
921     break;
922   }
923 }
924 
925 void MipsAsmPrinter::EmitFPCallStub(
926     const char *Symbol, const Mips16HardFloatInfo::FuncSignature *Signature) {
927   using namespace Mips16HardFloatInfo;
928 
929   MCSymbol *MSymbol = OutContext.getOrCreateSymbol(StringRef(Symbol));
930   bool LE = getDataLayout().isLittleEndian();
931   // Construct a local MCSubtargetInfo here.
932   // This is because the MachineFunction won't exist (but have not yet been
933   // freed) and since we're at the global level we can use the default
934   // constructed subtarget.
935   std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
936       TM.getTargetTriple().str(), TM.getTargetCPU(),
937       TM.getTargetFeatureString()));
938 
939   //
940   // .global xxxx
941   //
942   OutStreamer->EmitSymbolAttribute(MSymbol, MCSA_Global);
943   const char *RetType;
944   //
945   // make the comment field identifying the return and parameter
946   // types of the floating point stub
947   // # Stub function to call rettype xxxx (params)
948   //
949   switch (Signature->RetSig) {
950   case FRet:
951     RetType = "float";
952     break;
953   case DRet:
954     RetType = "double";
955     break;
956   case CFRet:
957     RetType = "complex";
958     break;
959   case CDRet:
960     RetType = "double complex";
961     break;
962   case NoFPRet:
963     RetType = "";
964     break;
965   }
966   const char *Parms;
967   switch (Signature->ParamSig) {
968   case FSig:
969     Parms = "float";
970     break;
971   case FFSig:
972     Parms = "float, float";
973     break;
974   case FDSig:
975     Parms = "float, double";
976     break;
977   case DSig:
978     Parms = "double";
979     break;
980   case DDSig:
981     Parms = "double, double";
982     break;
983   case DFSig:
984     Parms = "double, float";
985     break;
986   case NoSig:
987     Parms = "";
988     break;
989   }
990   OutStreamer->AddComment("\t# Stub function to call " + Twine(RetType) + " " +
991                           Twine(Symbol) + " (" + Twine(Parms) + ")");
992   //
993   // probably not necessary but we save and restore the current section state
994   //
995   OutStreamer->PushSection();
996   //
997   // .section mips16.call.fpxxxx,"ax",@progbits
998   //
999   MCSectionELF *M = OutContext.getELFSection(
1000       ".mips16.call.fp." + std::string(Symbol), ELF::SHT_PROGBITS,
1001       ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
1002   OutStreamer->SwitchSection(M, nullptr);
1003   //
1004   // .align 2
1005   //
1006   OutStreamer->EmitValueToAlignment(4);
1007   MipsTargetStreamer &TS = getTargetStreamer();
1008   //
1009   // .set nomips16
1010   // .set nomicromips
1011   //
1012   TS.emitDirectiveSetNoMips16();
1013   TS.emitDirectiveSetNoMicroMips();
1014   //
1015   // .ent __call_stub_fp_xxxx
1016   // .type  __call_stub_fp_xxxx,@function
1017   //  __call_stub_fp_xxxx:
1018   //
1019   std::string x = "__call_stub_fp_" + std::string(Symbol);
1020   MCSymbolELF *Stub =
1021       cast<MCSymbolELF>(OutContext.getOrCreateSymbol(StringRef(x)));
1022   TS.emitDirectiveEnt(*Stub);
1023   MCSymbol *MType =
1024       OutContext.getOrCreateSymbol("__call_stub_fp_" + Twine(Symbol));
1025   OutStreamer->EmitSymbolAttribute(MType, MCSA_ELF_TypeFunction);
1026   OutStreamer->EmitLabel(Stub);
1027 
1028   // Only handle non-pic for now.
1029   assert(!isPositionIndependent() &&
1030          "should not be here if we are compiling pic");
1031   TS.emitDirectiveSetReorder();
1032   //
1033   // We need to add a MipsMCExpr class to MCTargetDesc to fully implement
1034   // stubs without raw text but this current patch is for compiler generated
1035   // functions and they all return some value.
1036   // The calling sequence for non pic is different in that case and we need
1037   // to implement %lo and %hi in order to handle the case of no return value
1038   // See the corresponding method in Mips16HardFloat for details.
1039   //
1040   // mov the return address to S2.
1041   // we have no stack space to store it and we are about to make another call.
1042   // We need to make sure that the enclosing function knows to save S2
1043   // This should have already been handled.
1044   //
1045   // Mov $18, $31
1046 
1047   EmitInstrRegRegReg(*STI, Mips::OR, Mips::S2, Mips::RA, Mips::ZERO);
1048 
1049   EmitSwapFPIntParams(*STI, Signature->ParamSig, LE, true);
1050 
1051   // Jal xxxx
1052   //
1053   EmitJal(*STI, MSymbol);
1054 
1055   // fix return values
1056   EmitSwapFPIntRetval(*STI, Signature->RetSig, LE);
1057   //
1058   // do the return
1059   // if (Signature->RetSig == NoFPRet)
1060   //  llvm_unreachable("should not be any stubs here with no return value");
1061   // else
1062   EmitInstrReg(*STI, Mips::JR, Mips::S2);
1063 
1064   MCSymbol *Tmp = OutContext.createTempSymbol();
1065   OutStreamer->EmitLabel(Tmp);
1066   const MCSymbolRefExpr *E = MCSymbolRefExpr::create(Stub, OutContext);
1067   const MCSymbolRefExpr *T = MCSymbolRefExpr::create(Tmp, OutContext);
1068   const MCExpr *T_min_E = MCBinaryExpr::createSub(T, E, OutContext);
1069   OutStreamer->emitELFSize(Stub, T_min_E);
1070   TS.emitDirectiveEnd(x);
1071   OutStreamer->PopSection();
1072 }
1073 
1074 void MipsAsmPrinter::EmitEndOfAsmFile(Module &M) {
1075   // Emit needed stubs
1076   //
1077   for (std::map<
1078            const char *,
1079            const Mips16HardFloatInfo::FuncSignature *>::const_iterator
1080            it = StubsNeeded.begin();
1081        it != StubsNeeded.end(); ++it) {
1082     const char *Symbol = it->first;
1083     const Mips16HardFloatInfo::FuncSignature *Signature = it->second;
1084     EmitFPCallStub(Symbol, Signature);
1085   }
1086   // return to the text section
1087   OutStreamer->SwitchSection(OutContext.getObjectFileInfo()->getTextSection());
1088 }
1089 
1090 void MipsAsmPrinter::EmitSled(const MachineInstr &MI, SledKind Kind) {
1091   const uint8_t NoopsInSledCount = Subtarget->isGP64bit() ? 15 : 11;
1092   // For mips32 we want to emit the following pattern:
1093   //
1094   // .Lxray_sled_N:
1095   //   ALIGN
1096   //   B .tmpN
1097   //   11 NOP instructions (44 bytes)
1098   //   ADDIU T9, T9, 52
1099   // .tmpN
1100   //
1101   // We need the 44 bytes (11 instructions) because at runtime, we'd
1102   // be patching over the full 48 bytes (12 instructions) with the following
1103   // pattern:
1104   //
1105   //   ADDIU    SP, SP, -8
1106   //   NOP
1107   //   SW       RA, 4(SP)
1108   //   SW       T9, 0(SP)
1109   //   LUI      T9, %hi(__xray_FunctionEntry/Exit)
1110   //   ORI      T9, T9, %lo(__xray_FunctionEntry/Exit)
1111   //   LUI      T0, %hi(function_id)
1112   //   JALR     T9
1113   //   ORI      T0, T0, %lo(function_id)
1114   //   LW       T9, 0(SP)
1115   //   LW       RA, 4(SP)
1116   //   ADDIU    SP, SP, 8
1117   //
1118   // We add 52 bytes to t9 because we want to adjust the function pointer to
1119   // the actual start of function i.e. the address just after the noop sled.
1120   // We do this because gp displacement relocation is emitted at the start of
1121   // of the function i.e after the nop sled and to correctly calculate the
1122   // global offset table address, t9 must hold the address of the instruction
1123   // containing the gp displacement relocation.
1124   // FIXME: Is this correct for the static relocation model?
1125   //
1126   // For mips64 we want to emit the following pattern:
1127   //
1128   // .Lxray_sled_N:
1129   //   ALIGN
1130   //   B .tmpN
1131   //   15 NOP instructions (60 bytes)
1132   // .tmpN
1133   //
1134   // We need the 60 bytes (15 instructions) because at runtime, we'd
1135   // be patching over the full 64 bytes (16 instructions) with the following
1136   // pattern:
1137   //
1138   //   DADDIU   SP, SP, -16
1139   //   NOP
1140   //   SD       RA, 8(SP)
1141   //   SD       T9, 0(SP)
1142   //   LUI      T9, %highest(__xray_FunctionEntry/Exit)
1143   //   ORI      T9, T9, %higher(__xray_FunctionEntry/Exit)
1144   //   DSLL     T9, T9, 16
1145   //   ORI      T9, T9, %hi(__xray_FunctionEntry/Exit)
1146   //   DSLL     T9, T9, 16
1147   //   ORI      T9, T9, %lo(__xray_FunctionEntry/Exit)
1148   //   LUI      T0, %hi(function_id)
1149   //   JALR     T9
1150   //   ADDIU    T0, T0, %lo(function_id)
1151   //   LD       T9, 0(SP)
1152   //   LD       RA, 8(SP)
1153   //   DADDIU   SP, SP, 16
1154   //
1155   OutStreamer->EmitCodeAlignment(4);
1156   auto CurSled = OutContext.createTempSymbol("xray_sled_", true);
1157   OutStreamer->EmitLabel(CurSled);
1158   auto Target = OutContext.createTempSymbol();
1159 
1160   // Emit "B .tmpN" instruction, which jumps over the nop sled to the actual
1161   // start of function
1162   const MCExpr *TargetExpr = MCSymbolRefExpr::create(
1163       Target, MCSymbolRefExpr::VariantKind::VK_None, OutContext);
1164   EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::BEQ)
1165                                    .addReg(Mips::ZERO)
1166                                    .addReg(Mips::ZERO)
1167                                    .addExpr(TargetExpr));
1168 
1169   for (int8_t I = 0; I < NoopsInSledCount; I++)
1170     EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::SLL)
1171                                      .addReg(Mips::ZERO)
1172                                      .addReg(Mips::ZERO)
1173                                      .addImm(0));
1174 
1175   OutStreamer->EmitLabel(Target);
1176 
1177   if (!Subtarget->isGP64bit()) {
1178     EmitToStreamer(*OutStreamer,
1179                    MCInstBuilder(Mips::ADDiu)
1180                        .addReg(Mips::T9)
1181                        .addReg(Mips::T9)
1182                        .addImm(0x34));
1183   }
1184 
1185   recordSled(CurSled, MI, Kind);
1186 }
1187 
1188 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI) {
1189   EmitSled(MI, SledKind::FUNCTION_ENTER);
1190 }
1191 
1192 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI) {
1193   EmitSled(MI, SledKind::FUNCTION_EXIT);
1194 }
1195 
1196 void MipsAsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI) {
1197   EmitSled(MI, SledKind::TAIL_CALL);
1198 }
1199 
1200 void MipsAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
1201                                            raw_ostream &OS) {
1202   // TODO: implement
1203 }
1204 
1205 // Emit .dtprelword or .dtpreldword directive
1206 // and value for debug thread local expression.
1207 void MipsAsmPrinter::EmitDebugValue(const MCExpr *Value, unsigned Size) const {
1208   if (auto *MipsExpr = dyn_cast<MipsMCExpr>(Value)) {
1209     if (MipsExpr && MipsExpr->getKind() == MipsMCExpr::MEK_DTPREL) {
1210       switch (Size) {
1211       case 4:
1212         OutStreamer->EmitDTPRel32Value(MipsExpr->getSubExpr());
1213         break;
1214       case 8:
1215         OutStreamer->EmitDTPRel64Value(MipsExpr->getSubExpr());
1216         break;
1217       default:
1218         llvm_unreachable("Unexpected size of expression value.");
1219       }
1220       return;
1221     }
1222   }
1223   AsmPrinter::EmitDebugValue(Value, Size);
1224 }
1225 
1226 // Align all targets of indirect branches on bundle size.  Used only if target
1227 // is NaCl.
1228 void MipsAsmPrinter::NaClAlignIndirectJumpTargets(MachineFunction &MF) {
1229   // Align all blocks that are jumped to through jump table.
1230   if (MachineJumpTableInfo *JtInfo = MF.getJumpTableInfo()) {
1231     const std::vector<MachineJumpTableEntry> &JT = JtInfo->getJumpTables();
1232     for (unsigned I = 0; I < JT.size(); ++I) {
1233       const std::vector<MachineBasicBlock*> &MBBs = JT[I].MBBs;
1234 
1235       for (unsigned J = 0; J < MBBs.size(); ++J)
1236         MBBs[J]->setAlignment(MIPS_NACL_BUNDLE_ALIGN);
1237     }
1238   }
1239 
1240   // If basic block address is taken, block can be target of indirect branch.
1241   for (auto &MBB : MF) {
1242     if (MBB.hasAddressTaken())
1243       MBB.setAlignment(MIPS_NACL_BUNDLE_ALIGN);
1244   }
1245 }
1246 
1247 bool MipsAsmPrinter::isLongBranchPseudo(int Opcode) const {
1248   return (Opcode == Mips::LONG_BRANCH_LUi
1249           || Opcode == Mips::LONG_BRANCH_LUi2Op
1250           || Opcode == Mips::LONG_BRANCH_LUi2Op_64
1251           || Opcode == Mips::LONG_BRANCH_ADDiu
1252           || Opcode == Mips::LONG_BRANCH_ADDiu2Op
1253           || Opcode == Mips::LONG_BRANCH_DADDiu
1254           || Opcode == Mips::LONG_BRANCH_DADDiu2Op);
1255 }
1256 
1257 // Force static initialization.
1258 extern "C" void LLVMInitializeMipsAsmPrinter() {
1259   RegisterAsmPrinter<MipsAsmPrinter> X(getTheMipsTarget());
1260   RegisterAsmPrinter<MipsAsmPrinter> Y(getTheMipselTarget());
1261   RegisterAsmPrinter<MipsAsmPrinter> A(getTheMips64Target());
1262   RegisterAsmPrinter<MipsAsmPrinter> B(getTheMips64elTarget());
1263 }
1264