xref: /freebsd/contrib/llvm-project/llvm/lib/Target/Mips/MipsAsmPrinter.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 //===- MipsAsmPrinter.cpp - Mips LLVM Assembly Printer --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains a printer that converts from our internal representation
10 // of machine-dependent LLVM code to GAS-format MIPS assembly language.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MipsAsmPrinter.h"
15 #include "MCTargetDesc/MipsABIInfo.h"
16 #include "MCTargetDesc/MipsBaseInfo.h"
17 #include "MCTargetDesc/MipsInstPrinter.h"
18 #include "MCTargetDesc/MipsMCNaCl.h"
19 #include "MCTargetDesc/MipsMCTargetDesc.h"
20 #include "Mips.h"
21 #include "MipsMCInstLower.h"
22 #include "MipsMachineFunction.h"
23 #include "MipsSubtarget.h"
24 #include "MipsTargetMachine.h"
25 #include "MipsTargetStreamer.h"
26 #include "TargetInfo/MipsTargetInfo.h"
27 #include "llvm/ADT/SmallString.h"
28 #include "llvm/ADT/StringRef.h"
29 #include "llvm/ADT/Twine.h"
30 #include "llvm/BinaryFormat/ELF.h"
31 #include "llvm/CodeGen/MachineBasicBlock.h"
32 #include "llvm/CodeGen/MachineConstantPool.h"
33 #include "llvm/CodeGen/MachineFrameInfo.h"
34 #include "llvm/CodeGen/MachineFunction.h"
35 #include "llvm/CodeGen/MachineInstr.h"
36 #include "llvm/CodeGen/MachineJumpTableInfo.h"
37 #include "llvm/CodeGen/MachineOperand.h"
38 #include "llvm/CodeGen/TargetRegisterInfo.h"
39 #include "llvm/CodeGen/TargetSubtargetInfo.h"
40 #include "llvm/IR/Attributes.h"
41 #include "llvm/IR/BasicBlock.h"
42 #include "llvm/IR/DataLayout.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/InlineAsm.h"
45 #include "llvm/IR/Instructions.h"
46 #include "llvm/IR/Module.h"
47 #include "llvm/MC/MCContext.h"
48 #include "llvm/MC/MCExpr.h"
49 #include "llvm/MC/MCInst.h"
50 #include "llvm/MC/MCInstBuilder.h"
51 #include "llvm/MC/MCObjectFileInfo.h"
52 #include "llvm/MC/MCSectionELF.h"
53 #include "llvm/MC/MCSymbol.h"
54 #include "llvm/MC/MCSymbolELF.h"
55 #include "llvm/MC/TargetRegistry.h"
56 #include "llvm/Support/Casting.h"
57 #include "llvm/Support/ErrorHandling.h"
58 #include "llvm/Support/raw_ostream.h"
59 #include "llvm/Target/TargetLoweringObjectFile.h"
60 #include "llvm/Target/TargetMachine.h"
61 #include "llvm/TargetParser/Triple.h"
62 #include <cassert>
63 #include <cstdint>
64 #include <map>
65 #include <memory>
66 #include <string>
67 #include <vector>
68 
69 using namespace llvm;
70 
71 #define DEBUG_TYPE "mips-asm-printer"
72 
73 extern cl::opt<bool> EmitJalrReloc;
74 
getTargetStreamer() const75 MipsTargetStreamer &MipsAsmPrinter::getTargetStreamer() const {
76   return static_cast<MipsTargetStreamer &>(*OutStreamer->getTargetStreamer());
77 }
78 
runOnMachineFunction(MachineFunction & MF)79 bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
80   Subtarget = &MF.getSubtarget<MipsSubtarget>();
81 
82   MipsFI = MF.getInfo<MipsFunctionInfo>();
83   if (Subtarget->inMips16Mode())
84     for (const auto &I : MipsFI->StubsNeeded) {
85       const char *Symbol = I.first;
86       const Mips16HardFloatInfo::FuncSignature *Signature = I.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 
lowerOperand(const MachineOperand & MO,MCOperand & MCOp)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.
emitPseudoIndirectBranch(MCStreamer & OutStreamer,const MachineInstr * MI)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 // If there is an MO_JALR operand, insert:
152 //
153 // .reloc tmplabel, R_{MICRO}MIPS_JALR, symbol
154 // tmplabel:
155 //
156 // This is an optimization hint for the linker which may then replace
157 // an indirect call with a direct branch.
emitDirectiveRelocJalr(const MachineInstr & MI,MCContext & OutContext,TargetMachine & TM,MCStreamer & OutStreamer,const MipsSubtarget & Subtarget)158 static void emitDirectiveRelocJalr(const MachineInstr &MI,
159                                    MCContext &OutContext,
160                                    TargetMachine &TM,
161                                    MCStreamer &OutStreamer,
162                                    const MipsSubtarget &Subtarget) {
163   for (const MachineOperand &MO :
164        llvm::drop_begin(MI.operands(), MI.getDesc().getNumOperands())) {
165     if (MO.isMCSymbol() && (MO.getTargetFlags() & MipsII::MO_JALR)) {
166       MCSymbol *Callee = MO.getMCSymbol();
167       if (Callee && !Callee->getName().empty()) {
168         MCSymbol *OffsetLabel = OutContext.createTempSymbol();
169         const MCExpr *OffsetExpr =
170             MCSymbolRefExpr::create(OffsetLabel, OutContext);
171         const MCExpr *CaleeExpr =
172             MCSymbolRefExpr::create(Callee, OutContext);
173         OutStreamer.emitRelocDirective(
174             *OffsetExpr,
175             Subtarget.inMicroMipsMode() ? "R_MICROMIPS_JALR" : "R_MIPS_JALR",
176             CaleeExpr, SMLoc(), *TM.getMCSubtargetInfo());
177         OutStreamer.emitLabel(OffsetLabel);
178         return;
179       }
180     }
181   }
182 }
183 
emitInstruction(const MachineInstr * MI)184 void MipsAsmPrinter::emitInstruction(const MachineInstr *MI) {
185   // FIXME: Enable feature predicate checks once all the test pass.
186   // Mips_MC::verifyInstructionPredicates(MI->getOpcode(),
187   //                                      getSubtargetInfo().getFeatureBits());
188 
189   MipsTargetStreamer &TS = getTargetStreamer();
190   unsigned Opc = MI->getOpcode();
191   TS.forbidModuleDirective();
192 
193   if (MI->isDebugValue()) {
194     SmallString<128> Str;
195     raw_svector_ostream OS(Str);
196 
197     PrintDebugValueComment(MI, OS);
198     return;
199   }
200   if (MI->isDebugLabel())
201     return;
202 
203   // If we just ended a constant pool, mark it as such.
204   if (InConstantPool && Opc != Mips::CONSTPOOL_ENTRY) {
205     OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
206     InConstantPool = false;
207   }
208   if (Opc == Mips::CONSTPOOL_ENTRY) {
209     // CONSTPOOL_ENTRY - This instruction represents a floating
210     // constant pool in the function.  The first operand is the ID#
211     // for this instruction, the second is the index into the
212     // MachineConstantPool that this is, the third is the size in
213     // bytes of this constant pool entry.
214     // The required alignment is specified on the basic block holding this MI.
215     //
216     unsigned LabelId = (unsigned)MI->getOperand(0).getImm();
217     unsigned CPIdx = (unsigned)MI->getOperand(1).getIndex();
218 
219     // If this is the first entry of the pool, mark it.
220     if (!InConstantPool) {
221       OutStreamer->emitDataRegion(MCDR_DataRegion);
222       InConstantPool = true;
223     }
224 
225     OutStreamer->emitLabel(GetCPISymbol(LabelId));
226 
227     const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx];
228     if (MCPE.isMachineConstantPoolEntry())
229       emitMachineConstantPoolValue(MCPE.Val.MachineCPVal);
230     else
231       emitGlobalConstant(MF->getDataLayout(), MCPE.Val.ConstVal);
232     return;
233   }
234 
235   switch (Opc) {
236   case Mips::PATCHABLE_FUNCTION_ENTER:
237     LowerPATCHABLE_FUNCTION_ENTER(*MI);
238     return;
239   case Mips::PATCHABLE_FUNCTION_EXIT:
240     LowerPATCHABLE_FUNCTION_EXIT(*MI);
241     return;
242   case Mips::PATCHABLE_TAIL_CALL:
243     LowerPATCHABLE_TAIL_CALL(*MI);
244     return;
245   }
246 
247   if (EmitJalrReloc &&
248       (MI->isReturn() || MI->isCall() || MI->isIndirectBranch())) {
249     emitDirectiveRelocJalr(*MI, OutContext, TM, *OutStreamer, *Subtarget);
250   }
251 
252   MachineBasicBlock::const_instr_iterator I = MI->getIterator();
253   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
254 
255   do {
256     // Do any auto-generated pseudo lowerings.
257     if (emitPseudoExpansionLowering(*OutStreamer, &*I))
258       continue;
259 
260     // Skip the BUNDLE pseudo instruction and lower the contents
261     if (I->isBundle())
262       continue;
263 
264     if (I->getOpcode() == Mips::PseudoReturn ||
265         I->getOpcode() == Mips::PseudoReturn64 ||
266         I->getOpcode() == Mips::PseudoIndirectBranch ||
267         I->getOpcode() == Mips::PseudoIndirectBranch64 ||
268         I->getOpcode() == Mips::TAILCALLREG ||
269         I->getOpcode() == Mips::TAILCALLREG64) {
270       emitPseudoIndirectBranch(*OutStreamer, &*I);
271       continue;
272     }
273 
274     // The inMips16Mode() test is not permanent.
275     // Some instructions are marked as pseudo right now which
276     // would make the test fail for the wrong reason but
277     // that will be fixed soon. We need this here because we are
278     // removing another test for this situation downstream in the
279     // callchain.
280     //
281     if (I->isPseudo() && !Subtarget->inMips16Mode()
282         && !isLongBranchPseudo(I->getOpcode()))
283       llvm_unreachable("Pseudo opcode found in emitInstruction()");
284 
285     MCInst TmpInst0;
286     MCInstLowering.Lower(&*I, TmpInst0);
287     EmitToStreamer(*OutStreamer, TmpInst0);
288   } while ((++I != E) && I->isInsideBundle()); // Delay slot check
289 }
290 
291 //===----------------------------------------------------------------------===//
292 //
293 //  Mips Asm Directives
294 //
295 //  -- Frame directive "frame Stackpointer, Stacksize, RARegister"
296 //  Describe the stack frame.
297 //
298 //  -- Mask directives "(f)mask  bitmask, offset"
299 //  Tells the assembler which registers are saved and where.
300 //  bitmask - contain a little endian bitset indicating which registers are
301 //            saved on function prologue (e.g. with a 0x80000000 mask, the
302 //            assembler knows the register 31 (RA) is saved at prologue.
303 //  offset  - the position before stack pointer subtraction indicating where
304 //            the first saved register on prologue is located. (e.g. with a
305 //
306 //  Consider the following function prologue:
307 //
308 //    .frame  $fp,48,$ra
309 //    .mask   0xc0000000,-8
310 //       addiu $sp, $sp, -48
311 //       sw $ra, 40($sp)
312 //       sw $fp, 36($sp)
313 //
314 //    With a 0xc0000000 mask, the assembler knows the register 31 (RA) and
315 //    30 (FP) are saved at prologue. As the save order on prologue is from
316 //    left to right, RA is saved first. A -8 offset means that after the
317 //    stack pointer subtration, the first register in the mask (RA) will be
318 //    saved at address 48-8=40.
319 //
320 //===----------------------------------------------------------------------===//
321 
322 //===----------------------------------------------------------------------===//
323 // Mask directives
324 //===----------------------------------------------------------------------===//
325 
326 // Create a bitmask with all callee saved registers for CPU or Floating Point
327 // registers. For CPU registers consider RA, GP and FP for saving if necessary.
printSavedRegsBitmask()328 void MipsAsmPrinter::printSavedRegsBitmask() {
329   // CPU and FPU Saved Registers Bitmasks
330   unsigned CPUBitmask = 0, FPUBitmask = 0;
331   int CPUTopSavedRegOff, FPUTopSavedRegOff;
332 
333   // Set the CPU and FPU Bitmasks
334   const MachineFrameInfo &MFI = MF->getFrameInfo();
335   const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
336   const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
337   // size of stack area to which FP callee-saved regs are saved.
338   unsigned CPURegSize = TRI->getRegSizeInBits(Mips::GPR32RegClass) / 8;
339   unsigned FGR32RegSize = TRI->getRegSizeInBits(Mips::FGR32RegClass) / 8;
340   unsigned AFGR64RegSize = TRI->getRegSizeInBits(Mips::AFGR64RegClass) / 8;
341   bool HasAFGR64Reg = false;
342   unsigned CSFPRegsSize = 0;
343 
344   for (const auto &I : CSI) {
345     Register Reg = I.getReg();
346     unsigned RegNum = TRI->getEncodingValue(Reg);
347 
348     // If it's a floating point register, set the FPU Bitmask.
349     // If it's a general purpose register, set the CPU Bitmask.
350     if (Mips::FGR32RegClass.contains(Reg)) {
351       FPUBitmask |= (1 << RegNum);
352       CSFPRegsSize += FGR32RegSize;
353     } else if (Mips::AFGR64RegClass.contains(Reg)) {
354       FPUBitmask |= (3 << RegNum);
355       CSFPRegsSize += AFGR64RegSize;
356       HasAFGR64Reg = true;
357     } else if (Mips::GPR32RegClass.contains(Reg))
358       CPUBitmask |= (1 << RegNum);
359   }
360 
361   // FP Regs are saved right below where the virtual frame pointer points to.
362   FPUTopSavedRegOff = FPUBitmask ?
363     (HasAFGR64Reg ? -AFGR64RegSize : -FGR32RegSize) : 0;
364 
365   // CPU Regs are saved below FP Regs.
366   CPUTopSavedRegOff = CPUBitmask ? -CSFPRegsSize - CPURegSize : 0;
367 
368   MipsTargetStreamer &TS = getTargetStreamer();
369   // Print CPUBitmask
370   TS.emitMask(CPUBitmask, CPUTopSavedRegOff);
371 
372   // Print FPUBitmask
373   TS.emitFMask(FPUBitmask, FPUTopSavedRegOff);
374 }
375 
376 //===----------------------------------------------------------------------===//
377 // Frame and Set directives
378 //===----------------------------------------------------------------------===//
379 
380 /// Frame Directive
emitFrameDirective()381 void MipsAsmPrinter::emitFrameDirective() {
382   const TargetRegisterInfo &RI = *MF->getSubtarget().getRegisterInfo();
383 
384   Register stackReg = RI.getFrameRegister(*MF);
385   unsigned returnReg = RI.getRARegister();
386   unsigned stackSize = MF->getFrameInfo().getStackSize();
387 
388   getTargetStreamer().emitFrame(stackReg, stackSize, returnReg);
389 }
390 
391 /// Emit Set directives.
getCurrentABIString() const392 const char *MipsAsmPrinter::getCurrentABIString() const {
393   switch (static_cast<MipsTargetMachine &>(TM).getABI().GetEnumValue()) {
394   case MipsABIInfo::ABI::O32:  return "abi32";
395   case MipsABIInfo::ABI::N32:  return "abiN32";
396   case MipsABIInfo::ABI::N64:  return "abi64";
397   default: llvm_unreachable("Unknown Mips ABI");
398   }
399 }
400 
emitFunctionEntryLabel()401 void MipsAsmPrinter::emitFunctionEntryLabel() {
402   MipsTargetStreamer &TS = getTargetStreamer();
403 
404   // NaCl sandboxing requires that indirect call instructions are masked.
405   // This means that function entry points should be bundle-aligned.
406   if (Subtarget->isTargetNaCl())
407     emitAlignment(std::max(MF->getAlignment(), MIPS_NACL_BUNDLE_ALIGN));
408 
409   if (Subtarget->inMicroMipsMode()) {
410     TS.emitDirectiveSetMicroMips();
411     TS.setUsesMicroMips();
412     TS.updateABIInfo(*Subtarget);
413   } else
414     TS.emitDirectiveSetNoMicroMips();
415 
416   if (Subtarget->inMips16Mode())
417     TS.emitDirectiveSetMips16();
418   else
419     TS.emitDirectiveSetNoMips16();
420 
421   TS.emitDirectiveEnt(*CurrentFnSym);
422   OutStreamer->emitLabel(CurrentFnSym);
423 }
424 
425 /// EmitFunctionBodyStart - Targets can override this to emit stuff before
426 /// the first basic block in the function.
emitFunctionBodyStart()427 void MipsAsmPrinter::emitFunctionBodyStart() {
428   MipsTargetStreamer &TS = getTargetStreamer();
429 
430   MCInstLowering.Initialize(&MF->getContext());
431 
432   bool IsNakedFunction = MF->getFunction().hasFnAttribute(Attribute::Naked);
433   if (!IsNakedFunction)
434     emitFrameDirective();
435 
436   if (!IsNakedFunction)
437     printSavedRegsBitmask();
438 
439   if (!Subtarget->inMips16Mode()) {
440     TS.emitDirectiveSetNoReorder();
441     TS.emitDirectiveSetNoMacro();
442     TS.emitDirectiveSetNoAt();
443   }
444 }
445 
446 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
447 /// the last basic block in the function.
emitFunctionBodyEnd()448 void MipsAsmPrinter::emitFunctionBodyEnd() {
449   MipsTargetStreamer &TS = getTargetStreamer();
450 
451   // There are instruction for this macros, but they must
452   // always be at the function end, and we can't emit and
453   // break with BB logic.
454   if (!Subtarget->inMips16Mode()) {
455     TS.emitDirectiveSetAt();
456     TS.emitDirectiveSetMacro();
457     TS.emitDirectiveSetReorder();
458   }
459   TS.emitDirectiveEnd(CurrentFnSym->getName());
460   // Make sure to terminate any constant pools that were at the end
461   // of the function.
462   if (!InConstantPool)
463     return;
464   InConstantPool = false;
465   OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
466 }
467 
emitBasicBlockEnd(const MachineBasicBlock & MBB)468 void MipsAsmPrinter::emitBasicBlockEnd(const MachineBasicBlock &MBB) {
469   AsmPrinter::emitBasicBlockEnd(MBB);
470   MipsTargetStreamer &TS = getTargetStreamer();
471   if (MBB.empty())
472     TS.emitDirectiveInsn();
473 }
474 
475 // Print out an operand for an inline asm expression.
PrintAsmOperand(const MachineInstr * MI,unsigned OpNum,const char * ExtraCode,raw_ostream & O)476 bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
477                                      const char *ExtraCode, raw_ostream &O) {
478   // Does this asm operand have a single letter operand modifier?
479   if (ExtraCode && ExtraCode[0]) {
480     if (ExtraCode[1] != 0) return true; // Unknown modifier.
481 
482     const MachineOperand &MO = MI->getOperand(OpNum);
483     switch (ExtraCode[0]) {
484     default:
485       // See if this is a generic print operand
486       return AsmPrinter::PrintAsmOperand(MI, OpNum, ExtraCode, O);
487     case 'X': // hex const int
488       if (!MO.isImm())
489         return true;
490       O << "0x" << Twine::utohexstr(MO.getImm());
491       return false;
492     case 'x': // hex const int (low 16 bits)
493       if (!MO.isImm())
494         return true;
495       O << "0x" << Twine::utohexstr(MO.getImm() & 0xffff);
496       return false;
497     case 'd': // decimal const int
498       if (!MO.isImm())
499         return true;
500       O << MO.getImm();
501       return false;
502     case 'm': // decimal const int minus 1
503       if (!MO.isImm())
504         return true;
505       O << MO.getImm() - 1;
506       return false;
507     case 'y': // exact log2
508       if (!MO.isImm())
509         return true;
510       if (!isPowerOf2_64(MO.getImm()))
511         return true;
512       O << Log2_64(MO.getImm());
513       return false;
514     case 'z':
515       // $0 if zero, regular printing otherwise
516       if (MO.isImm() && MO.getImm() == 0) {
517         O << "$0";
518         return false;
519       }
520       // If not, call printOperand as normal.
521       break;
522     case 'D': // Second part of a double word register operand
523     case 'L': // Low order register of a double word register operand
524     case 'M': // High order register of a double word register operand
525     {
526       if (OpNum == 0)
527         return true;
528       const MachineOperand &FlagsOP = MI->getOperand(OpNum - 1);
529       if (!FlagsOP.isImm())
530         return true;
531       const InlineAsm::Flag Flags(FlagsOP.getImm());
532       const unsigned NumVals = Flags.getNumOperandRegisters();
533       // Number of registers represented by this operand. We are looking
534       // for 2 for 32 bit mode and 1 for 64 bit mode.
535       if (NumVals != 2) {
536         if (Subtarget->isGP64bit() && NumVals == 1 && MO.isReg()) {
537           Register Reg = MO.getReg();
538           O << '$' << MipsInstPrinter::getRegisterName(Reg);
539           return false;
540         }
541         return true;
542       }
543 
544       unsigned RegOp = OpNum;
545       if (!Subtarget->isGP64bit()){
546         // Endianness reverses which register holds the high or low value
547         // between M and L.
548         switch(ExtraCode[0]) {
549         case 'M':
550           RegOp = (Subtarget->isLittle()) ? OpNum + 1 : OpNum;
551           break;
552         case 'L':
553           RegOp = (Subtarget->isLittle()) ? OpNum : OpNum + 1;
554           break;
555         case 'D': // Always the second part
556           RegOp = OpNum + 1;
557         }
558         if (RegOp >= MI->getNumOperands())
559           return true;
560         const MachineOperand &MO = MI->getOperand(RegOp);
561         if (!MO.isReg())
562           return true;
563         Register Reg = MO.getReg();
564         O << '$' << MipsInstPrinter::getRegisterName(Reg);
565         return false;
566       }
567       break;
568     }
569     case 'w': {
570       MCRegister w = getMSARegFromFReg(MO.getReg());
571       if (w != Mips::NoRegister) {
572         O << '$' << MipsInstPrinter::getRegisterName(w);
573         return false;
574       }
575       break;
576     }
577     }
578   }
579 
580   printOperand(MI, OpNum, O);
581   return false;
582 }
583 
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNum,const char * ExtraCode,raw_ostream & O)584 bool MipsAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
585                                            unsigned OpNum,
586                                            const char *ExtraCode,
587                                            raw_ostream &O) {
588   assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands");
589   const MachineOperand &BaseMO = MI->getOperand(OpNum);
590   const MachineOperand &OffsetMO = MI->getOperand(OpNum + 1);
591   assert(BaseMO.isReg() &&
592          "Unexpected base pointer for inline asm memory operand.");
593   assert(OffsetMO.isImm() &&
594          "Unexpected offset for inline asm memory operand.");
595   int Offset = OffsetMO.getImm();
596 
597   // Currently we are expecting either no ExtraCode or 'D','M','L'.
598   if (ExtraCode) {
599     switch (ExtraCode[0]) {
600     case 'D':
601       Offset += 4;
602       break;
603     case 'M':
604       if (Subtarget->isLittle())
605         Offset += 4;
606       break;
607     case 'L':
608       if (!Subtarget->isLittle())
609         Offset += 4;
610       break;
611     default:
612       return true; // Unknown modifier.
613     }
614   }
615 
616   O << Offset << "($" << MipsInstPrinter::getRegisterName(BaseMO.getReg())
617     << ")";
618 
619   return false;
620 }
621 
printOperand(const MachineInstr * MI,int opNum,raw_ostream & O)622 void MipsAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
623                                   raw_ostream &O) {
624   const MachineOperand &MO = MI->getOperand(opNum);
625   bool closeP = false;
626 
627   if (MO.getTargetFlags())
628     closeP = true;
629 
630   switch(MO.getTargetFlags()) {
631   case MipsII::MO_GPREL:    O << "%gp_rel("; break;
632   case MipsII::MO_GOT_CALL: O << "%call16("; break;
633   case MipsII::MO_GOT:      O << "%got(";    break;
634   case MipsII::MO_ABS_HI:   O << "%hi(";     break;
635   case MipsII::MO_ABS_LO:   O << "%lo(";     break;
636   case MipsII::MO_HIGHER:   O << "%higher("; break;
637   case MipsII::MO_HIGHEST:  O << "%highest(("; break;
638   case MipsII::MO_TLSGD:    O << "%tlsgd(";  break;
639   case MipsII::MO_GOTTPREL: O << "%gottprel("; break;
640   case MipsII::MO_TPREL_HI: O << "%tprel_hi("; break;
641   case MipsII::MO_TPREL_LO: O << "%tprel_lo("; break;
642   case MipsII::MO_GPOFF_HI: O << "%hi(%neg(%gp_rel("; break;
643   case MipsII::MO_GPOFF_LO: O << "%lo(%neg(%gp_rel("; break;
644   case MipsII::MO_GOT_DISP: O << "%got_disp("; break;
645   case MipsII::MO_GOT_PAGE: O << "%got_page("; break;
646   case MipsII::MO_GOT_OFST: O << "%got_ofst("; break;
647   }
648 
649   switch (MO.getType()) {
650     case MachineOperand::MO_Register:
651       O << '$'
652         << StringRef(MipsInstPrinter::getRegisterName(MO.getReg())).lower();
653       break;
654 
655     case MachineOperand::MO_Immediate:
656       O << MO.getImm();
657       break;
658 
659     case MachineOperand::MO_MachineBasicBlock:
660       MO.getMBB()->getSymbol()->print(O, MAI);
661       return;
662 
663     case MachineOperand::MO_GlobalAddress:
664       PrintSymbolOperand(MO, O);
665       break;
666 
667     case MachineOperand::MO_BlockAddress: {
668       MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
669       O << BA->getName();
670       break;
671     }
672 
673     case MachineOperand::MO_ConstantPoolIndex:
674       O << getDataLayout().getPrivateGlobalPrefix() << "CPI"
675         << getFunctionNumber() << "_" << MO.getIndex();
676       if (MO.getOffset())
677         O << "+" << MO.getOffset();
678       break;
679 
680     default:
681       llvm_unreachable("<unknown operand type>");
682   }
683 
684   if (closeP) O << ")";
685 }
686 
687 void MipsAsmPrinter::
printMemOperand(const MachineInstr * MI,int opNum,raw_ostream & O)688 printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O) {
689   // Load/Store memory operands -- imm($reg)
690   // If PIC target the target is loaded as the
691   // pattern lw $25,%call16($28)
692 
693   // opNum can be invalid if instruction has reglist as operand.
694   // MemOperand is always last operand of instruction (base + offset).
695   switch (MI->getOpcode()) {
696   default:
697     break;
698   case Mips::SWM32_MM:
699   case Mips::LWM32_MM:
700     opNum = MI->getNumOperands() - 2;
701     break;
702   }
703 
704   printOperand(MI, opNum+1, O);
705   O << "(";
706   printOperand(MI, opNum, O);
707   O << ")";
708 }
709 
710 void MipsAsmPrinter::
printMemOperandEA(const MachineInstr * MI,int opNum,raw_ostream & O)711 printMemOperandEA(const MachineInstr *MI, int opNum, raw_ostream &O) {
712   // when using stack locations for not load/store instructions
713   // print the same way as all normal 3 operand instructions.
714   printOperand(MI, opNum, O);
715   O << ", ";
716   printOperand(MI, opNum+1, O);
717 }
718 
719 void MipsAsmPrinter::
printFCCOperand(const MachineInstr * MI,int opNum,raw_ostream & O,const char * Modifier)720 printFCCOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
721                 const char *Modifier) {
722   const MachineOperand &MO = MI->getOperand(opNum);
723   O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm());
724 }
725 
726 void MipsAsmPrinter::
printRegisterList(const MachineInstr * MI,int opNum,raw_ostream & O)727 printRegisterList(const MachineInstr *MI, int opNum, raw_ostream &O) {
728   for (int i = opNum, e = MI->getNumOperands(); i != e; ++i) {
729     if (i != opNum) O << ", ";
730     printOperand(MI, i, O);
731   }
732 }
733 
emitStartOfAsmFile(Module & M)734 void MipsAsmPrinter::emitStartOfAsmFile(Module &M) {
735   MipsTargetStreamer &TS = getTargetStreamer();
736 
737   // MipsTargetStreamer has an initialization order problem when emitting an
738   // object file directly (see MipsTargetELFStreamer for full details). Work
739   // around it by re-initializing the PIC state here.
740   TS.setPic(OutContext.getObjectFileInfo()->isPositionIndependent());
741 
742   // Try to get target-features from the first function.
743   StringRef FS = TM.getTargetFeatureString();
744   Module::iterator F = M.begin();
745   if (FS.empty() && M.size() && F->hasFnAttribute("target-features"))
746     FS = F->getFnAttribute("target-features").getValueAsString();
747 
748   // Compute MIPS architecture attributes based on the default subtarget
749   // that we'd have constructed.
750   // FIXME: For ifunc related functions we could iterate over and look
751   // for a feature string that doesn't match the default one.
752   const Triple &TT = TM.getTargetTriple();
753   StringRef CPU = MIPS_MC::selectMipsCPU(TT, TM.getTargetCPU());
754   const MipsTargetMachine &MTM = static_cast<const MipsTargetMachine &>(TM);
755   const MipsSubtarget STI(TT, CPU, FS, MTM.isLittleEndian(), MTM, std::nullopt);
756 
757   bool IsABICalls = STI.isABICalls();
758   const MipsABIInfo &ABI = MTM.getABI();
759   if (IsABICalls) {
760     TS.emitDirectiveAbiCalls();
761     // FIXME: This condition should be a lot more complicated that it is here.
762     //        Ideally it should test for properties of the ABI and not the ABI
763     //        itself.
764     //        For the moment, I'm only correcting enough to make MIPS-IV work.
765     if (!isPositionIndependent() && STI.hasSym32())
766       TS.emitDirectiveOptionPic0();
767   }
768 
769   // Tell the assembler which ABI we are using
770   std::string SectionName = std::string(".mdebug.") + getCurrentABIString();
771   OutStreamer->switchSection(
772       OutContext.getELFSection(SectionName, ELF::SHT_PROGBITS, 0));
773 
774   // NaN: At the moment we only support:
775   // 1. .nan legacy (default)
776   // 2. .nan 2008
777   STI.isNaN2008() ? TS.emitDirectiveNaN2008()
778                   : TS.emitDirectiveNaNLegacy();
779 
780   // TODO: handle O64 ABI
781 
782   TS.updateABIInfo(STI);
783 
784   // We should always emit a '.module fp=...' but binutils 2.24 does not accept
785   // it. We therefore emit it when it contradicts the ABI defaults (-mfpxx or
786   // -mfp64) and omit it otherwise.
787   if ((ABI.IsO32() && (STI.isABI_FPXX() || STI.isFP64bit())) ||
788       STI.useSoftFloat())
789     TS.emitDirectiveModuleFP();
790 
791   // We should always emit a '.module [no]oddspreg' but binutils 2.24 does not
792   // accept it. We therefore emit it when it contradicts the default or an
793   // option has changed the default (i.e. FPXX) and omit it otherwise.
794   if (ABI.IsO32() && (!STI.useOddSPReg() || STI.isABI_FPXX()))
795     TS.emitDirectiveModuleOddSPReg();
796 
797   // Switch to the .text section.
798   OutStreamer->switchSection(getObjFileLowering().getTextSection());
799 }
800 
emitInlineAsmStart() const801 void MipsAsmPrinter::emitInlineAsmStart() const {
802   MipsTargetStreamer &TS = getTargetStreamer();
803 
804   // GCC's choice of assembler options for inline assembly code ('at', 'macro'
805   // and 'reorder') is different from LLVM's choice for generated code ('noat',
806   // 'nomacro' and 'noreorder').
807   // In order to maintain compatibility with inline assembly code which depends
808   // on GCC's assembler options being used, we have to switch to those options
809   // for the duration of the inline assembly block and then switch back.
810   TS.emitDirectiveSetPush();
811   TS.emitDirectiveSetAt();
812   TS.emitDirectiveSetMacro();
813   TS.emitDirectiveSetReorder();
814   OutStreamer->addBlankLine();
815 }
816 
emitInlineAsmEnd(const MCSubtargetInfo & StartInfo,const MCSubtargetInfo * EndInfo) const817 void MipsAsmPrinter::emitInlineAsmEnd(const MCSubtargetInfo &StartInfo,
818                                       const MCSubtargetInfo *EndInfo) const {
819   OutStreamer->addBlankLine();
820   getTargetStreamer().emitDirectiveSetPop();
821 }
822 
EmitJal(const MCSubtargetInfo & STI,MCSymbol * Symbol)823 void MipsAsmPrinter::EmitJal(const MCSubtargetInfo &STI, MCSymbol *Symbol) {
824   MCInst I;
825   I.setOpcode(Mips::JAL);
826   I.addOperand(
827       MCOperand::createExpr(MCSymbolRefExpr::create(Symbol, OutContext)));
828   OutStreamer->emitInstruction(I, STI);
829 }
830 
EmitInstrReg(const MCSubtargetInfo & STI,unsigned Opcode,unsigned Reg)831 void MipsAsmPrinter::EmitInstrReg(const MCSubtargetInfo &STI, unsigned Opcode,
832                                   unsigned Reg) {
833   MCInst I;
834   I.setOpcode(Opcode);
835   I.addOperand(MCOperand::createReg(Reg));
836   OutStreamer->emitInstruction(I, STI);
837 }
838 
EmitInstrRegReg(const MCSubtargetInfo & STI,unsigned Opcode,unsigned Reg1,unsigned Reg2)839 void MipsAsmPrinter::EmitInstrRegReg(const MCSubtargetInfo &STI,
840                                      unsigned Opcode, unsigned Reg1,
841                                      unsigned Reg2) {
842   MCInst I;
843   //
844   // Because of the current td files for Mips32, the operands for MTC1
845   // appear backwards from their normal assembly order. It's not a trivial
846   // change to fix this in the td file so we adjust for it here.
847   //
848   if (Opcode == Mips::MTC1) {
849     unsigned Temp = Reg1;
850     Reg1 = Reg2;
851     Reg2 = Temp;
852   }
853   I.setOpcode(Opcode);
854   I.addOperand(MCOperand::createReg(Reg1));
855   I.addOperand(MCOperand::createReg(Reg2));
856   OutStreamer->emitInstruction(I, STI);
857 }
858 
EmitInstrRegRegReg(const MCSubtargetInfo & STI,unsigned Opcode,unsigned Reg1,unsigned Reg2,unsigned Reg3)859 void MipsAsmPrinter::EmitInstrRegRegReg(const MCSubtargetInfo &STI,
860                                         unsigned Opcode, unsigned Reg1,
861                                         unsigned Reg2, unsigned Reg3) {
862   MCInst I;
863   I.setOpcode(Opcode);
864   I.addOperand(MCOperand::createReg(Reg1));
865   I.addOperand(MCOperand::createReg(Reg2));
866   I.addOperand(MCOperand::createReg(Reg3));
867   OutStreamer->emitInstruction(I, STI);
868 }
869 
EmitMovFPIntPair(const MCSubtargetInfo & STI,unsigned MovOpc,unsigned Reg1,unsigned Reg2,unsigned FPReg1,unsigned FPReg2,bool LE)870 void MipsAsmPrinter::EmitMovFPIntPair(const MCSubtargetInfo &STI,
871                                       unsigned MovOpc, unsigned Reg1,
872                                       unsigned Reg2, unsigned FPReg1,
873                                       unsigned FPReg2, bool LE) {
874   if (!LE) {
875     unsigned temp = Reg1;
876     Reg1 = Reg2;
877     Reg2 = temp;
878   }
879   EmitInstrRegReg(STI, MovOpc, Reg1, FPReg1);
880   EmitInstrRegReg(STI, MovOpc, Reg2, FPReg2);
881 }
882 
EmitSwapFPIntParams(const MCSubtargetInfo & STI,Mips16HardFloatInfo::FPParamVariant PV,bool LE,bool ToFP)883 void MipsAsmPrinter::EmitSwapFPIntParams(const MCSubtargetInfo &STI,
884                                          Mips16HardFloatInfo::FPParamVariant PV,
885                                          bool LE, bool ToFP) {
886   using namespace Mips16HardFloatInfo;
887 
888   unsigned MovOpc = ToFP ? Mips::MTC1 : Mips::MFC1;
889   switch (PV) {
890   case FSig:
891     EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12);
892     break;
893   case FFSig:
894     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F14, LE);
895     break;
896   case FDSig:
897     EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12);
898     EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE);
899     break;
900   case DSig:
901     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
902     break;
903   case DDSig:
904     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
905     EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE);
906     break;
907   case DFSig:
908     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE);
909     EmitInstrRegReg(STI, MovOpc, Mips::A2, Mips::F14);
910     break;
911   case NoSig:
912     return;
913   }
914 }
915 
EmitSwapFPIntRetval(const MCSubtargetInfo & STI,Mips16HardFloatInfo::FPReturnVariant RV,bool LE)916 void MipsAsmPrinter::EmitSwapFPIntRetval(
917     const MCSubtargetInfo &STI, Mips16HardFloatInfo::FPReturnVariant RV,
918     bool LE) {
919   using namespace Mips16HardFloatInfo;
920 
921   unsigned MovOpc = Mips::MFC1;
922   switch (RV) {
923   case FRet:
924     EmitInstrRegReg(STI, MovOpc, Mips::V0, Mips::F0);
925     break;
926   case DRet:
927     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
928     break;
929   case CFRet:
930     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
931     break;
932   case CDRet:
933     EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE);
934     EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F2, Mips::F3, LE);
935     break;
936   case NoFPRet:
937     break;
938   }
939 }
940 
EmitFPCallStub(const char * Symbol,const Mips16HardFloatInfo::FuncSignature * Signature)941 void MipsAsmPrinter::EmitFPCallStub(
942     const char *Symbol, const Mips16HardFloatInfo::FuncSignature *Signature) {
943   using namespace Mips16HardFloatInfo;
944 
945   MCSymbol *MSymbol = OutContext.getOrCreateSymbol(StringRef(Symbol));
946   bool LE = getDataLayout().isLittleEndian();
947   // Construct a local MCSubtargetInfo here.
948   // This is because the MachineFunction won't exist (but have not yet been
949   // freed) and since we're at the global level we can use the default
950   // constructed subtarget.
951   std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
952       TM.getTargetTriple().str(), TM.getTargetCPU(),
953       TM.getTargetFeatureString()));
954 
955   //
956   // .global xxxx
957   //
958   OutStreamer->emitSymbolAttribute(MSymbol, MCSA_Global);
959   const char *RetType;
960   //
961   // make the comment field identifying the return and parameter
962   // types of the floating point stub
963   // # Stub function to call rettype xxxx (params)
964   //
965   switch (Signature->RetSig) {
966   case FRet:
967     RetType = "float";
968     break;
969   case DRet:
970     RetType = "double";
971     break;
972   case CFRet:
973     RetType = "complex";
974     break;
975   case CDRet:
976     RetType = "double complex";
977     break;
978   case NoFPRet:
979     RetType = "";
980     break;
981   }
982   const char *Parms;
983   switch (Signature->ParamSig) {
984   case FSig:
985     Parms = "float";
986     break;
987   case FFSig:
988     Parms = "float, float";
989     break;
990   case FDSig:
991     Parms = "float, double";
992     break;
993   case DSig:
994     Parms = "double";
995     break;
996   case DDSig:
997     Parms = "double, double";
998     break;
999   case DFSig:
1000     Parms = "double, float";
1001     break;
1002   case NoSig:
1003     Parms = "";
1004     break;
1005   }
1006   OutStreamer->AddComment("\t# Stub function to call " + Twine(RetType) + " " +
1007                           Twine(Symbol) + " (" + Twine(Parms) + ")");
1008   //
1009   // probably not necessary but we save and restore the current section state
1010   //
1011   OutStreamer->pushSection();
1012   //
1013   // .section mips16.call.fpxxxx,"ax",@progbits
1014   //
1015   MCSectionELF *M = OutContext.getELFSection(
1016       ".mips16.call.fp." + std::string(Symbol), ELF::SHT_PROGBITS,
1017       ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
1018   OutStreamer->switchSection(M);
1019   //
1020   // .align 2
1021   //
1022   OutStreamer->emitValueToAlignment(Align(4));
1023   MipsTargetStreamer &TS = getTargetStreamer();
1024   //
1025   // .set nomips16
1026   // .set nomicromips
1027   //
1028   TS.emitDirectiveSetNoMips16();
1029   TS.emitDirectiveSetNoMicroMips();
1030   //
1031   // .ent __call_stub_fp_xxxx
1032   // .type  __call_stub_fp_xxxx,@function
1033   //  __call_stub_fp_xxxx:
1034   //
1035   std::string x = "__call_stub_fp_" + std::string(Symbol);
1036   MCSymbolELF *Stub =
1037       cast<MCSymbolELF>(OutContext.getOrCreateSymbol(StringRef(x)));
1038   TS.emitDirectiveEnt(*Stub);
1039   MCSymbol *MType =
1040       OutContext.getOrCreateSymbol("__call_stub_fp_" + Twine(Symbol));
1041   OutStreamer->emitSymbolAttribute(MType, MCSA_ELF_TypeFunction);
1042   OutStreamer->emitLabel(Stub);
1043 
1044   // Only handle non-pic for now.
1045   assert(!isPositionIndependent() &&
1046          "should not be here if we are compiling pic");
1047   TS.emitDirectiveSetReorder();
1048   //
1049   // We need to add a MipsMCExpr class to MCTargetDesc to fully implement
1050   // stubs without raw text but this current patch is for compiler generated
1051   // functions and they all return some value.
1052   // The calling sequence for non pic is different in that case and we need
1053   // to implement %lo and %hi in order to handle the case of no return value
1054   // See the corresponding method in Mips16HardFloat for details.
1055   //
1056   // mov the return address to S2.
1057   // we have no stack space to store it and we are about to make another call.
1058   // We need to make sure that the enclosing function knows to save S2
1059   // This should have already been handled.
1060   //
1061   // Mov $18, $31
1062 
1063   EmitInstrRegRegReg(*STI, Mips::OR, Mips::S2, Mips::RA, Mips::ZERO);
1064 
1065   EmitSwapFPIntParams(*STI, Signature->ParamSig, LE, true);
1066 
1067   // Jal xxxx
1068   //
1069   EmitJal(*STI, MSymbol);
1070 
1071   // fix return values
1072   EmitSwapFPIntRetval(*STI, Signature->RetSig, LE);
1073   //
1074   // do the return
1075   // if (Signature->RetSig == NoFPRet)
1076   //  llvm_unreachable("should not be any stubs here with no return value");
1077   // else
1078   EmitInstrReg(*STI, Mips::JR, Mips::S2);
1079 
1080   MCSymbol *Tmp = OutContext.createTempSymbol();
1081   OutStreamer->emitLabel(Tmp);
1082   const MCSymbolRefExpr *E = MCSymbolRefExpr::create(Stub, OutContext);
1083   const MCSymbolRefExpr *T = MCSymbolRefExpr::create(Tmp, OutContext);
1084   const MCExpr *T_min_E = MCBinaryExpr::createSub(T, E, OutContext);
1085   OutStreamer->emitELFSize(Stub, T_min_E);
1086   TS.emitDirectiveEnd(x);
1087   OutStreamer->popSection();
1088 }
1089 
emitEndOfAsmFile(Module & M)1090 void MipsAsmPrinter::emitEndOfAsmFile(Module &M) {
1091   // Emit needed stubs
1092   //
1093   for (std::map<
1094            const char *,
1095            const Mips16HardFloatInfo::FuncSignature *>::const_iterator
1096            it = StubsNeeded.begin();
1097        it != StubsNeeded.end(); ++it) {
1098     const char *Symbol = it->first;
1099     const Mips16HardFloatInfo::FuncSignature *Signature = it->second;
1100     EmitFPCallStub(Symbol, Signature);
1101   }
1102   // return to the text section
1103   OutStreamer->switchSection(OutContext.getObjectFileInfo()->getTextSection());
1104 }
1105 
EmitSled(const MachineInstr & MI,SledKind Kind)1106 void MipsAsmPrinter::EmitSled(const MachineInstr &MI, SledKind Kind) {
1107   const uint8_t NoopsInSledCount = Subtarget->isGP64bit() ? 15 : 11;
1108   // For mips32 we want to emit the following pattern:
1109   //
1110   // .Lxray_sled_N:
1111   //   ALIGN
1112   //   B .tmpN
1113   //   11 NOP instructions (44 bytes)
1114   //   ADDIU T9, T9, 52
1115   // .tmpN
1116   //
1117   // We need the 44 bytes (11 instructions) because at runtime, we'd
1118   // be patching over the full 48 bytes (12 instructions) with the following
1119   // pattern:
1120   //
1121   //   ADDIU    SP, SP, -8
1122   //   NOP
1123   //   SW       RA, 4(SP)
1124   //   SW       T9, 0(SP)
1125   //   LUI      T9, %hi(__xray_FunctionEntry/Exit)
1126   //   ORI      T9, T9, %lo(__xray_FunctionEntry/Exit)
1127   //   LUI      T0, %hi(function_id)
1128   //   JALR     T9
1129   //   ORI      T0, T0, %lo(function_id)
1130   //   LW       T9, 0(SP)
1131   //   LW       RA, 4(SP)
1132   //   ADDIU    SP, SP, 8
1133   //
1134   // We add 52 bytes to t9 because we want to adjust the function pointer to
1135   // the actual start of function i.e. the address just after the noop sled.
1136   // We do this because gp displacement relocation is emitted at the start of
1137   // of the function i.e after the nop sled and to correctly calculate the
1138   // global offset table address, t9 must hold the address of the instruction
1139   // containing the gp displacement relocation.
1140   // FIXME: Is this correct for the static relocation model?
1141   //
1142   // For mips64 we want to emit the following pattern:
1143   //
1144   // .Lxray_sled_N:
1145   //   ALIGN
1146   //   B .tmpN
1147   //   15 NOP instructions (60 bytes)
1148   // .tmpN
1149   //
1150   // We need the 60 bytes (15 instructions) because at runtime, we'd
1151   // be patching over the full 64 bytes (16 instructions) with the following
1152   // pattern:
1153   //
1154   //   DADDIU   SP, SP, -16
1155   //   NOP
1156   //   SD       RA, 8(SP)
1157   //   SD       T9, 0(SP)
1158   //   LUI      T9, %highest(__xray_FunctionEntry/Exit)
1159   //   ORI      T9, T9, %higher(__xray_FunctionEntry/Exit)
1160   //   DSLL     T9, T9, 16
1161   //   ORI      T9, T9, %hi(__xray_FunctionEntry/Exit)
1162   //   DSLL     T9, T9, 16
1163   //   ORI      T9, T9, %lo(__xray_FunctionEntry/Exit)
1164   //   LUI      T0, %hi(function_id)
1165   //   JALR     T9
1166   //   ADDIU    T0, T0, %lo(function_id)
1167   //   LD       T9, 0(SP)
1168   //   LD       RA, 8(SP)
1169   //   DADDIU   SP, SP, 16
1170   //
1171   OutStreamer->emitCodeAlignment(Align(4), &getSubtargetInfo());
1172   auto CurSled = OutContext.createTempSymbol("xray_sled_", true);
1173   OutStreamer->emitLabel(CurSled);
1174   auto Target = OutContext.createTempSymbol();
1175 
1176   // Emit "B .tmpN" instruction, which jumps over the nop sled to the actual
1177   // start of function
1178   const MCExpr *TargetExpr = MCSymbolRefExpr::create(
1179       Target, MCSymbolRefExpr::VariantKind::VK_None, OutContext);
1180   EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::BEQ)
1181                                    .addReg(Mips::ZERO)
1182                                    .addReg(Mips::ZERO)
1183                                    .addExpr(TargetExpr));
1184 
1185   for (int8_t I = 0; I < NoopsInSledCount; I++)
1186     EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::SLL)
1187                                      .addReg(Mips::ZERO)
1188                                      .addReg(Mips::ZERO)
1189                                      .addImm(0));
1190 
1191   OutStreamer->emitLabel(Target);
1192 
1193   if (!Subtarget->isGP64bit()) {
1194     EmitToStreamer(*OutStreamer,
1195                    MCInstBuilder(Mips::ADDiu)
1196                        .addReg(Mips::T9)
1197                        .addReg(Mips::T9)
1198                        .addImm(0x34));
1199   }
1200 
1201   recordSled(CurSled, MI, Kind, 2);
1202 }
1203 
LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr & MI)1204 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI) {
1205   EmitSled(MI, SledKind::FUNCTION_ENTER);
1206 }
1207 
LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr & MI)1208 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI) {
1209   EmitSled(MI, SledKind::FUNCTION_EXIT);
1210 }
1211 
LowerPATCHABLE_TAIL_CALL(const MachineInstr & MI)1212 void MipsAsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI) {
1213   EmitSled(MI, SledKind::TAIL_CALL);
1214 }
1215 
PrintDebugValueComment(const MachineInstr * MI,raw_ostream & OS)1216 void MipsAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
1217                                            raw_ostream &OS) {
1218   // TODO: implement
1219 }
1220 
1221 // Emit .dtprelword or .dtpreldword directive
1222 // and value for debug thread local expression.
emitDebugValue(const MCExpr * Value,unsigned Size) const1223 void MipsAsmPrinter::emitDebugValue(const MCExpr *Value, unsigned Size) const {
1224   if (auto *MipsExpr = dyn_cast<MipsMCExpr>(Value)) {
1225     if (MipsExpr && MipsExpr->getKind() == MipsMCExpr::MEK_DTPREL) {
1226       switch (Size) {
1227       case 4:
1228         OutStreamer->emitDTPRel32Value(MipsExpr->getSubExpr());
1229         break;
1230       case 8:
1231         OutStreamer->emitDTPRel64Value(MipsExpr->getSubExpr());
1232         break;
1233       default:
1234         llvm_unreachable("Unexpected size of expression value.");
1235       }
1236       return;
1237     }
1238   }
1239   AsmPrinter::emitDebugValue(Value, Size);
1240 }
1241 
1242 // Align all targets of indirect branches on bundle size.  Used only if target
1243 // is NaCl.
NaClAlignIndirectJumpTargets(MachineFunction & MF)1244 void MipsAsmPrinter::NaClAlignIndirectJumpTargets(MachineFunction &MF) {
1245   // Align all blocks that are jumped to through jump table.
1246   if (MachineJumpTableInfo *JtInfo = MF.getJumpTableInfo()) {
1247     const std::vector<MachineJumpTableEntry> &JT = JtInfo->getJumpTables();
1248     for (const auto &I : JT) {
1249       const std::vector<MachineBasicBlock *> &MBBs = I.MBBs;
1250 
1251       for (MachineBasicBlock *MBB : MBBs)
1252         MBB->setAlignment(MIPS_NACL_BUNDLE_ALIGN);
1253     }
1254   }
1255 
1256   // If basic block address is taken, block can be target of indirect branch.
1257   for (auto &MBB : MF) {
1258     if (MBB.hasAddressTaken())
1259       MBB.setAlignment(MIPS_NACL_BUNDLE_ALIGN);
1260   }
1261 }
1262 
isLongBranchPseudo(int Opcode) const1263 bool MipsAsmPrinter::isLongBranchPseudo(int Opcode) const {
1264   return (Opcode == Mips::LONG_BRANCH_LUi
1265           || Opcode == Mips::LONG_BRANCH_LUi2Op
1266           || Opcode == Mips::LONG_BRANCH_LUi2Op_64
1267           || Opcode == Mips::LONG_BRANCH_ADDiu
1268           || Opcode == Mips::LONG_BRANCH_ADDiu2Op
1269           || Opcode == Mips::LONG_BRANCH_DADDiu
1270           || Opcode == Mips::LONG_BRANCH_DADDiu2Op);
1271 }
1272 
1273 // Force static initialization.
LLVMInitializeMipsAsmPrinter()1274 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeMipsAsmPrinter() {
1275   RegisterAsmPrinter<MipsAsmPrinter> X(getTheMipsTarget());
1276   RegisterAsmPrinter<MipsAsmPrinter> Y(getTheMipselTarget());
1277   RegisterAsmPrinter<MipsAsmPrinter> A(getTheMips64Target());
1278   RegisterAsmPrinter<MipsAsmPrinter> B(getTheMips64elTarget());
1279 }
1280