llvm/lib/CodeGen/StackMaps.cpp

   1 //===- StackMaps.cpp ------------------------------------------------------===//
   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 #include "llvm/CodeGen/StackMaps.h"
  10 #include "llvm/ADT/DenseMapInfo.h"
  11 #include "llvm/ADT/STLExtras.h"
  12 #include "llvm/ADT/Twine.h"
  13 #include "llvm/CodeGen/AsmPrinter.h"
  14 #include "llvm/CodeGen/MachineFrameInfo.h"
  15 #include "llvm/CodeGen/MachineFunction.h"
  16 #include "llvm/CodeGen/MachineInstr.h"
  17 #include "llvm/CodeGen/MachineOperand.h"
  18 #include "llvm/CodeGen/TargetOpcodes.h"
  19 #include "llvm/CodeGen/TargetRegisterInfo.h"
  20 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  21 #include "llvm/IR/DataLayout.h"
  22 #include "llvm/MC/MCContext.h"
  23 #include "llvm/MC/MCExpr.h"
  24 #include "llvm/MC/MCObjectFileInfo.h"
  25 #include "llvm/MC/MCRegisterInfo.h"
  26 #include "llvm/MC/MCStreamer.h"
  27 #include "llvm/Support/CommandLine.h"
  28 #include "llvm/Support/Debug.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/MathExtras.h"
  31 #include "llvm/Support/raw_ostream.h"
  32 #include <algorithm>
  33 #include <cassert>
  34 #include <cstdint>
  35 #include <iterator>
  36 #include <utility>
  37
  38 using namespace llvm;
  39
  40 #define DEBUG_TYPE "stackmaps"
  41
  42 static cl::opt<int> StackMapVersion(
  43     "stackmap-version", cl::init(3), cl::Hidden,
  44     cl::desc("Specify the stackmap encoding version (default = 3)"));
  45
  46 const char *StackMaps::WSMP = "Stack Maps: ";
  47
  48 static uint64_t getConstMetaVal(const MachineInstr &MI, unsigned Idx) {
  49   assert(MI.getOperand(Idx).isImm() &&
  50          MI.getOperand(Idx).getImm() == StackMaps::ConstantOp);
  51   const auto &MO = MI.getOperand(Idx + 1);
  52   assert(MO.isImm());
  53   return MO.getImm();
  54 }
  55
  56 StackMapOpers::StackMapOpers(const MachineInstr *MI)
  57   : MI(MI) {
  58   assert(getVarIdx() <= MI->getNumOperands() &&
  59          "invalid stackmap definition");
  60 }
  61
  62 PatchPointOpers::PatchPointOpers(const MachineInstr *MI)
  63     : MI(MI), HasDef(MI->getOperand(0).isReg() && MI->getOperand(0).isDef() &&
  64                      !MI->getOperand(0).isImplicit()) {
  65 #ifndef NDEBUG
  66   unsigned CheckStartIdx = 0, e = MI->getNumOperands();
  67   while (CheckStartIdx < e && MI->getOperand(CheckStartIdx).isReg() &&
  68          MI->getOperand(CheckStartIdx).isDef() &&
  69          !MI->getOperand(CheckStartIdx).isImplicit())
  70     ++CheckStartIdx;
  71
  72   assert(getMetaIdx() == CheckStartIdx &&
  73          "Unexpected additional definition in Patchpoint intrinsic.");
  74 #endif
  75 }
  76
  77 unsigned PatchPointOpers::getNextScratchIdx(unsigned StartIdx) const {
  78   if (!StartIdx)
  79     StartIdx = getVarIdx();
  80
  81   // Find the next scratch register (implicit def and early clobber)
  82   unsigned ScratchIdx = StartIdx, e = MI->getNumOperands();
  83   while (ScratchIdx < e &&
  84          !(MI->getOperand(ScratchIdx).isReg() &&
  85            MI->getOperand(ScratchIdx).isDef() &&
  86            MI->getOperand(ScratchIdx).isImplicit() &&
  87            MI->getOperand(ScratchIdx).isEarlyClobber()))
  88     ++ScratchIdx;
  89
  90   assert(ScratchIdx != e && "No scratch register available");
  91   return ScratchIdx;
  92 }
  93
  94 unsigned StatepointOpers::getNumGcMapEntriesIdx() {
  95   // Take index of num of allocas and skip all allocas records.
  96   unsigned CurIdx = getNumAllocaIdx();
  97   unsigned NumAllocas = getConstMetaVal(*MI, CurIdx - 1);
  98   CurIdx++;
  99   while (NumAllocas--)
 100     CurIdx = StackMaps::getNextMetaArgIdx(MI, CurIdx);
 101   return CurIdx + 1; // skip <StackMaps::ConstantOp>
 102 }
 103
 104 unsigned StatepointOpers::getNumAllocaIdx() {
 105   // Take index of num of gc ptrs and skip all gc ptr records.
 106   unsigned CurIdx = getNumGCPtrIdx();
 107   unsigned NumGCPtrs = getConstMetaVal(*MI, CurIdx - 1);
 108   CurIdx++;
 109   while (NumGCPtrs--)
 110     CurIdx = StackMaps::getNextMetaArgIdx(MI, CurIdx);
 111   return CurIdx + 1; // skip <StackMaps::ConstantOp>
 112 }
 113
 114 unsigned StatepointOpers::getNumGCPtrIdx() {
 115   // Take index of num of deopt args and skip all deopt records.
 116   unsigned CurIdx = getNumDeoptArgsIdx();
 117   unsigned NumDeoptArgs = getConstMetaVal(*MI, CurIdx - 1);
 118   CurIdx++;
 119   while (NumDeoptArgs--) {
 120     CurIdx = StackMaps::getNextMetaArgIdx(MI, CurIdx);
 121   }
 122   return CurIdx + 1; // skip <StackMaps::ConstantOp>
 123 }
 124
 125 int StatepointOpers::getFirstGCPtrIdx() {
 126   unsigned NumGCPtrsIdx = getNumGCPtrIdx();
 127   unsigned NumGCPtrs = getConstMetaVal(*MI, NumGCPtrsIdx - 1);
 128   if (NumGCPtrs == 0)
 129     return -1;
 130   ++NumGCPtrsIdx; // skip <num gc ptrs>
 131   assert(NumGCPtrsIdx < MI->getNumOperands());
 132   return (int)NumGCPtrsIdx;
 133 }
 134
 135 unsigned StatepointOpers::getGCPointerMap(
 136     SmallVectorImpl<std::pair<unsigned, unsigned>> &GCMap) {
 137   unsigned CurIdx = getNumGcMapEntriesIdx();
 138   unsigned GCMapSize = getConstMetaVal(*MI, CurIdx - 1);
 139   CurIdx++;
 140   for (unsigned N = 0; N < GCMapSize; ++N) {
 141     unsigned B = MI->getOperand(CurIdx++).getImm();
 142     unsigned D = MI->getOperand(CurIdx++).getImm();
 143     GCMap.push_back(std::make_pair(B, D));
 144   }
 145
 146   return GCMapSize;
 147 }
 148
 149 StackMaps::StackMaps(AsmPrinter &AP) : AP(AP) {
 150   if (StackMapVersion != 3)
 151     llvm_unreachable("Unsupported stackmap version!");
 152 }
 153
 154 unsigned StackMaps::getNextMetaArgIdx(const MachineInstr *MI, unsigned CurIdx) {
 155   assert(CurIdx < MI->getNumOperands() && "Bad meta arg index");
 156   const auto &MO = MI->getOperand(CurIdx);
 157   if (MO.isImm()) {
 158     switch (MO.getImm()) {
 159     default:
 160       llvm_unreachable("Unrecognized operand type.");
 161     case StackMaps::DirectMemRefOp:
 162       CurIdx += 2;
 163       break;
 164     case StackMaps::IndirectMemRefOp:
 165       CurIdx += 3;
 166       break;
 167     case StackMaps::ConstantOp:
 168       ++CurIdx;
 169       break;
 170     }
 171   }
 172   ++CurIdx;
 173   assert(CurIdx < MI->getNumOperands() && "points past operand list");
 174   return CurIdx;
 175 }
 176
 177 /// Go up the super-register chain until we hit a valid dwarf register number.
 178 static unsigned getDwarfRegNum(unsigned Reg, const TargetRegisterInfo *TRI) {
 179   int RegNum = TRI->getDwarfRegNum(Reg, false);
 180   for (MCSuperRegIterator SR(Reg, TRI); SR.isValid() && RegNum < 0; ++SR)
 181     RegNum = TRI->getDwarfRegNum(*SR, false);
 182
 183   assert(RegNum >= 0 && "Invalid Dwarf register number.");
 184   return (unsigned)RegNum;
 185 }
 186
 187 MachineInstr::const_mop_iterator
 188 StackMaps::parseOperand(MachineInstr::const_mop_iterator MOI,
 189                         MachineInstr::const_mop_iterator MOE, LocationVec &Locs,
 190                         LiveOutVec &LiveOuts) const {
 191   const TargetRegisterInfo *TRI = AP.MF->getSubtarget().getRegisterInfo();
 192   if (MOI->isImm()) {
 193     switch (MOI->getImm()) {
 194     default:
 195       llvm_unreachable("Unrecognized operand type.");
 196     case StackMaps::DirectMemRefOp: {
 197       auto &DL = AP.MF->getDataLayout();
 198
 199       unsigned Size = DL.getPointerSizeInBits();
 200       assert((Size % 8) == 0 && "Need pointer size in bytes.");
 201       Size /= 8;
 202       Register Reg = (++MOI)->getReg();
 203       int64_t Imm = (++MOI)->getImm();
 204       Locs.emplace_back(StackMaps::Location::Direct, Size,
 205                         getDwarfRegNum(Reg, TRI), Imm);
 206       break;
 207     }
 208     case StackMaps::IndirectMemRefOp: {
 209       int64_t Size = (++MOI)->getImm();
 210       assert(Size > 0 && "Need a valid size for indirect memory locations.");
 211       Register Reg = (++MOI)->getReg();
 212       int64_t Imm = (++MOI)->getImm();
 213       Locs.emplace_back(StackMaps::Location::Indirect, Size,
 214                         getDwarfRegNum(Reg, TRI), Imm);
 215       break;
 216     }
 217     case StackMaps::ConstantOp: {
 218       ++MOI;
 219       assert(MOI->isImm() && "Expected constant operand.");
 220       int64_t Imm = MOI->getImm();
 221       Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, Imm);
 222       break;
 223     }
 224     }
 225     return ++MOI;
 226   }
 227
 228   // The physical register number will ultimately be encoded as a DWARF regno.
 229   // The stack map also records the size of a spill slot that can hold the
 230   // register content. (The runtime can track the actual size of the data type
 231   // if it needs to.)
 232   if (MOI->isReg()) {
 233     // Skip implicit registers (this includes our scratch registers)
 234     if (MOI->isImplicit())
 235       return ++MOI;
 236
 237     if (MOI->isUndef()) {
 238       // Record `undef` register as constant. Use same value as ISel uses.
 239       Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, 0xFEFEFEFE);
 240       return ++MOI;
 241     }
 242
 243     assert(Register::isPhysicalRegister(MOI->getReg()) &&
 244            "Virtreg operands should have been rewritten before now.");
 245     const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(MOI->getReg());
 246     assert(!MOI->getSubReg() && "Physical subreg still around.");
 247
 248     unsigned Offset = 0;
 249     unsigned DwarfRegNum = getDwarfRegNum(MOI->getReg(), TRI);
 250     unsigned LLVMRegNum = *TRI->getLLVMRegNum(DwarfRegNum, false);
 251     unsigned SubRegIdx = TRI->getSubRegIndex(LLVMRegNum, MOI->getReg());
 252     if (SubRegIdx)
 253       Offset = TRI->getSubRegIdxOffset(SubRegIdx);
 254
 255     Locs.emplace_back(Location::Register, TRI->getSpillSize(*RC),
 256                       DwarfRegNum, Offset);
 257     return ++MOI;
 258   }
 259
 260   if (MOI->isRegLiveOut())
 261     LiveOuts = parseRegisterLiveOutMask(MOI->getRegLiveOut());
 262
 263   return ++MOI;
 264 }
 265
 266 void StackMaps::print(raw_ostream &OS) {
 267   const TargetRegisterInfo *TRI =
 268       AP.MF ? AP.MF->getSubtarget().getRegisterInfo() : nullptr;
 269   OS << WSMP << "callsites:\n";
 270   for (const auto &CSI : CSInfos) {
 271     const LocationVec &CSLocs = CSI.Locations;
 272     const LiveOutVec &LiveOuts = CSI.LiveOuts;
 273
 274     OS << WSMP << "callsite " << CSI.ID << "\n";
 275     OS << WSMP << "  has " << CSLocs.size() << " locations\n";
 276
 277     unsigned Idx = 0;
 278     for (const auto &Loc : CSLocs) {
 279       OS << WSMP << "\t\tLoc " << Idx << ": ";
 280       switch (Loc.Type) {
 281       case Location::Unprocessed:
 282         OS << "<Unprocessed operand>";
 283         break;
 284       case Location::Register:
 285         OS << "Register ";
 286         if (TRI)
 287           OS << printReg(Loc.Reg, TRI);
 288         else
 289           OS << Loc.Reg;
 290         break;
 291       case Location::Direct:
 292         OS << "Direct ";
 293         if (TRI)
 294           OS << printReg(Loc.Reg, TRI);
 295         else
 296           OS << Loc.Reg;
 297         if (Loc.Offset)
 298           OS << " + " << Loc.Offset;
 299         break;
 300       case Location::Indirect:
 301         OS << "Indirect ";
 302         if (TRI)
 303           OS << printReg(Loc.Reg, TRI);
 304         else
 305           OS << Loc.Reg;
 306         OS << "+" << Loc.Offset;
 307         break;
 308       case Location::Constant:
 309         OS << "Constant " << Loc.Offset;
 310         break;
 311       case Location::ConstantIndex:
 312         OS << "Constant Index " << Loc.Offset;
 313         break;
 314       }
 315       OS << "\t[encoding: .byte " << Loc.Type << ", .byte 0"
 316          << ", .short " << Loc.Size << ", .short " << Loc.Reg << ", .short 0"
 317          << ", .int " << Loc.Offset << "]\n";
 318       Idx++;
 319     }
 320
 321     OS << WSMP << "\thas " << LiveOuts.size() << " live-out registers\n";
 322
 323     Idx = 0;
 324     for (const auto &LO : LiveOuts) {
 325       OS << WSMP << "\t\tLO " << Idx << ": ";
 326       if (TRI)
 327         OS << printReg(LO.Reg, TRI);
 328       else
 329         OS << LO.Reg;
 330       OS << "\t[encoding: .short " << LO.DwarfRegNum << ", .byte 0, .byte "
 331          << LO.Size << "]\n";
 332       Idx++;
 333     }
 334   }
 335 }
 336
 337 /// Create a live-out register record for the given register Reg.
 338 StackMaps::LiveOutReg
 339 StackMaps::createLiveOutReg(unsigned Reg, const TargetRegisterInfo *TRI) const {
 340   unsigned DwarfRegNum = getDwarfRegNum(Reg, TRI);
 341   unsigned Size = TRI->getSpillSize(*TRI->getMinimalPhysRegClass(Reg));
 342   return LiveOutReg(Reg, DwarfRegNum, Size);
 343 }
 344
 345 /// Parse the register live-out mask and return a vector of live-out registers
 346 /// that need to be recorded in the stackmap.
 347 StackMaps::LiveOutVec
 348 StackMaps::parseRegisterLiveOutMask(const uint32_t *Mask) const {
 349   assert(Mask && "No register mask specified");
 350   const TargetRegisterInfo *TRI = AP.MF->getSubtarget().getRegisterInfo();
 351   LiveOutVec LiveOuts;
 352
 353   // Create a LiveOutReg for each bit that is set in the register mask.
 354   for (unsigned Reg = 0, NumRegs = TRI->getNumRegs(); Reg != NumRegs; ++Reg)
 355     if ((Mask[Reg / 32] >> (Reg % 32)) & 1)
 356       LiveOuts.push_back(createLiveOutReg(Reg, TRI));
 357
 358   // We don't need to keep track of a register if its super-register is already
 359   // in the list. Merge entries that refer to the same dwarf register and use
 360   // the maximum size that needs to be spilled.
 361
 362   llvm::sort(LiveOuts, [](const LiveOutReg &LHS, const LiveOutReg &RHS) {
 363     // Only sort by the dwarf register number.
 364     return LHS.DwarfRegNum < RHS.DwarfRegNum;
 365   });
 366
 367   for (auto I = LiveOuts.begin(), E = LiveOuts.end(); I != E; ++I) {
 368     for (auto *II = std::next(I); II != E; ++II) {
 369       if (I->DwarfRegNum != II->DwarfRegNum) {
 370         // Skip all the now invalid entries.
 371         I = --II;
 372         break;
 373       }
 374       I->Size = std::max(I->Size, II->Size);
 375       if (TRI->isSuperRegister(I->Reg, II->Reg))
 376         I->Reg = II->Reg;
 377       II->Reg = 0; // mark for deletion.
 378     }
 379   }
 380
 381   llvm::erase_if(LiveOuts, [](const LiveOutReg &LO) { return LO.Reg == 0; });
 382
 383   return LiveOuts;
 384 }
 385
 386 // See statepoint MI format description in StatepointOpers' class comment
 387 // in include/llvm/CodeGen/StackMaps.h
 388 void StackMaps::parseStatepointOpers(const MachineInstr &MI,
 389                                      MachineInstr::const_mop_iterator MOI,
 390                                      MachineInstr::const_mop_iterator MOE,
 391                                      LocationVec &Locations,
 392                                      LiveOutVec &LiveOuts) {
 393   LLVM_DEBUG(dbgs() << "record statepoint : " << MI << "\n");
 394   StatepointOpers SO(&MI);
 395   MOI = parseOperand(MOI, MOE, Locations, LiveOuts); // CC
 396   MOI = parseOperand(MOI, MOE, Locations, LiveOuts); // Flags
 397   MOI = parseOperand(MOI, MOE, Locations, LiveOuts); // Num Deopts
 398
 399   // Record Deopt Args.
 400   unsigned NumDeoptArgs = Locations.back().Offset;
 401   assert(Locations.back().Type == Location::Constant);
 402   assert(NumDeoptArgs == SO.getNumDeoptArgs());
 403
 404   while (NumDeoptArgs--)
 405     MOI = parseOperand(MOI, MOE, Locations, LiveOuts);
 406
 407   // Record gc base/derived pairs
 408   assert(MOI->isImm() && MOI->getImm() == StackMaps::ConstantOp);
 409   ++MOI;
 410   assert(MOI->isImm());
 411   unsigned NumGCPointers = MOI->getImm();
 412   ++MOI;
 413   if (NumGCPointers) {
 414     // Map logical index of GC ptr to MI operand index.
 415     SmallVector<unsigned, 8> GCPtrIndices;
 416     unsigned GCPtrIdx = (unsigned)SO.getFirstGCPtrIdx();
 417     assert((int)GCPtrIdx != -1);
 418     assert(MOI - MI.operands_begin() == GCPtrIdx + 0LL);
 419     while (NumGCPointers--) {
 420       GCPtrIndices.push_back(GCPtrIdx);
 421       GCPtrIdx = StackMaps::getNextMetaArgIdx(&MI, GCPtrIdx);
 422     }
 423
 424     SmallVector<std::pair<unsigned, unsigned>, 8> GCPairs;
 425     unsigned NumGCPairs = SO.getGCPointerMap(GCPairs);
 426     (void)NumGCPairs;
 427     LLVM_DEBUG(dbgs() << "NumGCPairs = " << NumGCPairs << "\n");
 428
 429     auto MOB = MI.operands_begin();
 430     for (auto &P : GCPairs) {
 431       assert(P.first < GCPtrIndices.size() && "base pointer index not found");
 432       assert(P.second < GCPtrIndices.size() &&
 433              "derived pointer index not found");
 434       unsigned BaseIdx = GCPtrIndices[P.first];
 435       unsigned DerivedIdx = GCPtrIndices[P.second];
 436       LLVM_DEBUG(dbgs() << "Base : " << BaseIdx << " Derived : " << DerivedIdx
 437                         << "\n");
 438       (void)parseOperand(MOB + BaseIdx, MOE, Locations, LiveOuts);
 439       (void)parseOperand(MOB + DerivedIdx, MOE, Locations, LiveOuts);
 440     }
 441
 442     MOI = MOB + GCPtrIdx;
 443   }
 444
 445   // Record gc allocas
 446   assert(MOI < MOE);
 447   assert(MOI->isImm() && MOI->getImm() == StackMaps::ConstantOp);
 448   ++MOI;
 449   unsigned NumAllocas = MOI->getImm();
 450   ++MOI;
 451   while (NumAllocas--) {
 452     MOI = parseOperand(MOI, MOE, Locations, LiveOuts);
 453     assert(MOI < MOE);
 454   }
 455 }
 456
 457 void StackMaps::recordStackMapOpers(const MCSymbol &MILabel,
 458                                     const MachineInstr &MI, uint64_t ID,
 459                                     MachineInstr::const_mop_iterator MOI,
 460                                     MachineInstr::const_mop_iterator MOE,
 461                                     bool recordResult) {
 462   MCContext &OutContext = AP.OutStreamer->getContext();
 463
 464   LocationVec Locations;
 465   LiveOutVec LiveOuts;
 466
 467   if (recordResult) {
 468     assert(PatchPointOpers(&MI).hasDef() && "Stackmap has no return value.");
 469     parseOperand(MI.operands_begin(), std::next(MI.operands_begin()), Locations,
 470                  LiveOuts);
 471   }
 472
 473   // Parse operands.
 474   if (MI.getOpcode() == TargetOpcode::STATEPOINT)
 475     parseStatepointOpers(MI, MOI, MOE, Locations, LiveOuts);
 476   else
 477     while (MOI != MOE)
 478       MOI = parseOperand(MOI, MOE, Locations, LiveOuts);
 479
 480   // Move large constants into the constant pool.
 481   for (auto &Loc : Locations) {
 482     // Constants are encoded as sign-extended integers.
 483     // -1 is directly encoded as .long 0xFFFFFFFF with no constant pool.
 484     if (Loc.Type == Location::Constant && !isInt<32>(Loc.Offset)) {
 485       Loc.Type = Location::ConstantIndex;
 486       // ConstPool is intentionally a MapVector of 'uint64_t's (as
 487       // opposed to 'int64_t's).  We should never be in a situation
 488       // where we have to insert either the tombstone or the empty
 489       // keys into a map, and for a DenseMap<uint64_t, T> these are
 490       // (uint64_t)0 and (uint64_t)-1.  They can be and are
 491       // represented using 32 bit integers.
 492       assert((uint64_t)Loc.Offset != DenseMapInfo<uint64_t>::getEmptyKey() &&
 493              (uint64_t)Loc.Offset !=
 494                  DenseMapInfo<uint64_t>::getTombstoneKey() &&
 495              "empty and tombstone keys should fit in 32 bits!");
 496       auto Result = ConstPool.insert(std::make_pair(Loc.Offset, Loc.Offset));
 497       Loc.Offset = Result.first - ConstPool.begin();
 498     }
 499   }
 500
 501   // Create an expression to calculate the offset of the callsite from function
 502   // entry.
 503   const MCExpr *CSOffsetExpr = MCBinaryExpr::createSub(
 504       MCSymbolRefExpr::create(&MILabel, OutContext),
 505       MCSymbolRefExpr::create(AP.CurrentFnSymForSize, OutContext), OutContext);
 506
 507   CSInfos.emplace_back(CSOffsetExpr, ID, std::move(Locations),
 508                        std::move(LiveOuts));
 509
 510   // Record the stack size of the current function and update callsite count.
 511   const MachineFrameInfo &MFI = AP.MF->getFrameInfo();
 512   const TargetRegisterInfo *RegInfo = AP.MF->getSubtarget().getRegisterInfo();
 513   bool HasDynamicFrameSize =
 514       MFI.hasVarSizedObjects() || RegInfo->hasStackRealignment(*(AP.MF));
 515   uint64_t FrameSize = HasDynamicFrameSize ? UINT64_MAX : MFI.getStackSize();
 516
 517   auto CurrentIt = FnInfos.find(AP.CurrentFnSym);
 518   if (CurrentIt != FnInfos.end())
 519     CurrentIt->second.RecordCount++;
 520   else
 521     FnInfos.insert(std::make_pair(AP.CurrentFnSym, FunctionInfo(FrameSize)));
 522 }
 523
 524 void StackMaps::recordStackMap(const MCSymbol &L, const MachineInstr &MI) {
 525   assert(MI.getOpcode() == TargetOpcode::STACKMAP && "expected stackmap");
 526
 527   StackMapOpers opers(&MI);
 528   const int64_t ID = MI.getOperand(PatchPointOpers::IDPos).getImm();
 529   recordStackMapOpers(L, MI, ID, std::next(MI.operands_begin(),
 530                                            opers.getVarIdx()),
 531                       MI.operands_end());
 532 }
 533
 534 void StackMaps::recordPatchPoint(const MCSymbol &L, const MachineInstr &MI) {
 535   assert(MI.getOpcode() == TargetOpcode::PATCHPOINT && "expected patchpoint");
 536
 537   PatchPointOpers opers(&MI);
 538   const int64_t ID = opers.getID();
 539   auto MOI = std::next(MI.operands_begin(), opers.getStackMapStartIdx());
 540   recordStackMapOpers(L, MI, ID, MOI, MI.operands_end(),
 541                       opers.isAnyReg() && opers.hasDef());
 542
 543 #ifndef NDEBUG
 544   // verify anyregcc
 545   auto &Locations = CSInfos.back().Locations;
 546   if (opers.isAnyReg()) {
 547     unsigned NArgs = opers.getNumCallArgs();
 548     for (unsigned i = 0, e = (opers.hasDef() ? NArgs + 1 : NArgs); i != e; ++i)
 549       assert(Locations[i].Type == Location::Register &&
 550              "anyreg arg must be in reg.");
 551   }
 552 #endif
 553 }
 554
 555 void StackMaps::recordStatepoint(const MCSymbol &L, const MachineInstr &MI) {
 556   assert(MI.getOpcode() == TargetOpcode::STATEPOINT && "expected statepoint");
 557
 558   StatepointOpers opers(&MI);
 559   const unsigned StartIdx = opers.getVarIdx();
 560   recordStackMapOpers(L, MI, opers.getID(), MI.operands_begin() + StartIdx,
 561                       MI.operands_end(), false);
 562 }
 563
 564 /// Emit the stackmap header.
 565 ///
 566 /// Header {
 567 ///   uint8  : Stack Map Version (currently 3)
 568 ///   uint8  : Reserved (expected to be 0)
 569 ///   uint16 : Reserved (expected to be 0)
 570 /// }
 571 /// uint32 : NumFunctions
 572 /// uint32 : NumConstants
 573 /// uint32 : NumRecords
 574 void StackMaps::emitStackmapHeader(MCStreamer &OS) {
 575   // Header.
 576   OS.emitIntValue(StackMapVersion, 1); // Version.
 577   OS.emitIntValue(0, 1);               // Reserved.
 578   OS.emitInt16(0);                     // Reserved.
 579
 580   // Num functions.
 581   LLVM_DEBUG(dbgs() << WSMP << "#functions = " << FnInfos.size() << '\n');
 582   OS.emitInt32(FnInfos.size());
 583   // Num constants.
 584   LLVM_DEBUG(dbgs() << WSMP << "#constants = " << ConstPool.size() << '\n');
 585   OS.emitInt32(ConstPool.size());
 586   // Num callsites.
 587   LLVM_DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << '\n');
 588   OS.emitInt32(CSInfos.size());
 589 }
 590
 591 /// Emit the function frame record for each function.
 592 ///
 593 /// StkSizeRecord[NumFunctions] {
 594 ///   uint64 : Function Address
 595 ///   uint64 : Stack Size
 596 ///   uint64 : Record Count
 597 /// }
 598 void StackMaps::emitFunctionFrameRecords(MCStreamer &OS) {
 599   // Function Frame records.
 600   LLVM_DEBUG(dbgs() << WSMP << "functions:\n");
 601   for (auto const &FR : FnInfos) {
 602     LLVM_DEBUG(dbgs() << WSMP << "function addr: " << FR.first
 603                       << " frame size: " << FR.second.StackSize
 604                       << " callsite count: " << FR.second.RecordCount << '\n');
 605     OS.emitSymbolValue(FR.first, 8);
 606     OS.emitIntValue(FR.second.StackSize, 8);
 607     OS.emitIntValue(FR.second.RecordCount, 8);
 608   }
 609 }
 610
 611 /// Emit the constant pool.
 612 ///
 613 /// int64  : Constants[NumConstants]
 614 void StackMaps::emitConstantPoolEntries(MCStreamer &OS) {
 615   // Constant pool entries.
 616   LLVM_DEBUG(dbgs() << WSMP << "constants:\n");
 617   for (const auto &ConstEntry : ConstPool) {
 618     LLVM_DEBUG(dbgs() << WSMP << ConstEntry.second << '\n');
 619     OS.emitIntValue(ConstEntry.second, 8);
 620   }
 621 }
 622
 623 /// Emit the callsite info for each callsite.
 624 ///
 625 /// StkMapRecord[NumRecords] {
 626 ///   uint64 : PatchPoint ID
 627 ///   uint32 : Instruction Offset
 628 ///   uint16 : Reserved (record flags)
 629 ///   uint16 : NumLocations
 630 ///   Location[NumLocations] {
 631 ///     uint8  : Register | Direct | Indirect | Constant | ConstantIndex
 632 ///     uint8  : Size in Bytes
 633 ///     uint16 : Dwarf RegNum
 634 ///     int32  : Offset
 635 ///   }
 636 ///   uint16 : Padding
 637 ///   uint16 : NumLiveOuts
 638 ///   LiveOuts[NumLiveOuts] {
 639 ///     uint16 : Dwarf RegNum
 640 ///     uint8  : Reserved
 641 ///     uint8  : Size in Bytes
 642 ///   }
 643 ///   uint32 : Padding (only if required to align to 8 byte)
 644 /// }
 645 ///
 646 /// Location Encoding, Type, Value:
 647 ///   0x1, Register, Reg                 (value in register)
 648 ///   0x2, Direct, Reg + Offset          (frame index)
 649 ///   0x3, Indirect, [Reg + Offset]      (spilled value)
 650 ///   0x4, Constant, Offset              (small constant)
 651 ///   0x5, ConstIndex, Constants[Offset] (large constant)
 652 void StackMaps::emitCallsiteEntries(MCStreamer &OS) {
 653   LLVM_DEBUG(print(dbgs()));
 654   // Callsite entries.
 655   for (const auto &CSI : CSInfos) {
 656     const LocationVec &CSLocs = CSI.Locations;
 657     const LiveOutVec &LiveOuts = CSI.LiveOuts;
 658
 659     // Verify stack map entry. It's better to communicate a problem to the
 660     // runtime than crash in case of in-process compilation. Currently, we do
 661     // simple overflow checks, but we may eventually communicate other
 662     // compilation errors this way.
 663     if (CSLocs.size() > UINT16_MAX || LiveOuts.size() > UINT16_MAX) {
 664       OS.emitIntValue(UINT64_MAX, 8); // Invalid ID.
 665       OS.emitValue(CSI.CSOffsetExpr, 4);
 666       OS.emitInt16(0); // Reserved.
 667       OS.emitInt16(0); // 0 locations.
 668       OS.emitInt16(0); // padding.
 669       OS.emitInt16(0); // 0 live-out registers.
 670       OS.emitInt32(0); // padding.
 671       continue;
 672     }
 673
 674     OS.emitIntValue(CSI.ID, 8);
 675     OS.emitValue(CSI.CSOffsetExpr, 4);
 676
 677     // Reserved for flags.
 678     OS.emitInt16(0);
 679     OS.emitInt16(CSLocs.size());
 680
 681     for (const auto &Loc : CSLocs) {
 682       OS.emitIntValue(Loc.Type, 1);
 683       OS.emitIntValue(0, 1);  // Reserved
 684       OS.emitInt16(Loc.Size);
 685       OS.emitInt16(Loc.Reg);
 686       OS.emitInt16(0); // Reserved
 687       OS.emitInt32(Loc.Offset);
 688     }
 689
 690     // Emit alignment to 8 byte.
 691     OS.emitValueToAlignment(8);
 692
 693     // Num live-out registers and padding to align to 4 byte.
 694     OS.emitInt16(0);
 695     OS.emitInt16(LiveOuts.size());
 696
 697     for (const auto &LO : LiveOuts) {
 698       OS.emitInt16(LO.DwarfRegNum);
 699       OS.emitIntValue(0, 1);
 700       OS.emitIntValue(LO.Size, 1);
 701     }
 702     // Emit alignment to 8 byte.
 703     OS.emitValueToAlignment(8);
 704   }
 705 }
 706
 707 /// Serialize the stackmap data.
 708 void StackMaps::serializeToStackMapSection() {
 709   (void)WSMP;
 710   // Bail out if there's no stack map data.
 711   assert((!CSInfos.empty() || ConstPool.empty()) &&
 712          "Expected empty constant pool too!");
 713   assert((!CSInfos.empty() || FnInfos.empty()) &&
 714          "Expected empty function record too!");
 715   if (CSInfos.empty())
 716     return;
 717
 718   MCContext &OutContext = AP.OutStreamer->getContext();
 719   MCStreamer &OS = *AP.OutStreamer;
 720
 721   // Create the section.
 722   MCSection *StackMapSection =
 723       OutContext.getObjectFileInfo()->getStackMapSection();
 724   OS.switchSection(StackMapSection);
 725
 726   // Emit a dummy symbol to force section inclusion.
 727   OS.emitLabel(OutContext.getOrCreateSymbol(Twine("__LLVM_StackMaps")));
 728
 729   // Serialize data.
 730   LLVM_DEBUG(dbgs() << "********** Stack Map Output **********\n");
 731   emitStackmapHeader(OS);
 732   emitFunctionFrameRecords(OS);
 733   emitConstantPoolEntries(OS);
 734   emitCallsiteEntries(OS);
 735   OS.addBlankLine();
 736
 737   // Clean up.
 738   CSInfos.clear();
 739   ConstPool.clear();
 740 }