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diff --git a/llvm/lib/CodeGen/StackMaps.cpp b/llvm/lib/CodeGen/StackMaps.cpp
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+//===- StackMaps.cpp ------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/StackMaps.h"
+#include "llvm/ADT/DenseMapInfo.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/TargetOpcodes.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <iterator>
+#include <utility>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "stackmaps"
+
+static cl::opt<int> StackMapVersion(
+ "stackmap-version", cl::init(3), cl::Hidden,
+ cl::desc("Specify the stackmap encoding version (default = 3)"));
+
+const char *StackMaps::WSMP = "Stack Maps: ";
+
+StackMapOpers::StackMapOpers(const MachineInstr *MI)
+ : MI(MI) {
+ assert(getVarIdx() <= MI->getNumOperands() &&
+ "invalid stackmap definition");
+}
+
+PatchPointOpers::PatchPointOpers(const MachineInstr *MI)
+ : MI(MI), HasDef(MI->getOperand(0).isReg() && MI->getOperand(0).isDef() &&
+ !MI->getOperand(0).isImplicit()) {
+#ifndef NDEBUG
+ unsigned CheckStartIdx = 0, e = MI->getNumOperands();
+ while (CheckStartIdx < e && MI->getOperand(CheckStartIdx).isReg() &&
+ MI->getOperand(CheckStartIdx).isDef() &&
+ !MI->getOperand(CheckStartIdx).isImplicit())
+ ++CheckStartIdx;
+
+ assert(getMetaIdx() == CheckStartIdx &&
+ "Unexpected additional definition in Patchpoint intrinsic.");
+#endif
+}
+
+unsigned PatchPointOpers::getNextScratchIdx(unsigned StartIdx) const {
+ if (!StartIdx)
+ StartIdx = getVarIdx();
+
+ // Find the next scratch register (implicit def and early clobber)
+ unsigned ScratchIdx = StartIdx, e = MI->getNumOperands();
+ while (ScratchIdx < e &&
+ !(MI->getOperand(ScratchIdx).isReg() &&
+ MI->getOperand(ScratchIdx).isDef() &&
+ MI->getOperand(ScratchIdx).isImplicit() &&
+ MI->getOperand(ScratchIdx).isEarlyClobber()))
+ ++ScratchIdx;
+
+ assert(ScratchIdx != e && "No scratch register available");
+ return ScratchIdx;
+}
+
+StackMaps::StackMaps(AsmPrinter &AP) : AP(AP) {
+ if (StackMapVersion != 3)
+ llvm_unreachable("Unsupported stackmap version!");
+}
+
+/// Go up the super-register chain until we hit a valid dwarf register number.
+static unsigned getDwarfRegNum(unsigned Reg, const TargetRegisterInfo *TRI) {
+ int RegNum = TRI->getDwarfRegNum(Reg, false);
+ for (MCSuperRegIterator SR(Reg, TRI); SR.isValid() && RegNum < 0; ++SR)
+ RegNum = TRI->getDwarfRegNum(*SR, false);
+
+ assert(RegNum >= 0 && "Invalid Dwarf register number.");
+ return (unsigned)RegNum;
+}
+
+MachineInstr::const_mop_iterator
+StackMaps::parseOperand(MachineInstr::const_mop_iterator MOI,
+ MachineInstr::const_mop_iterator MOE, LocationVec &Locs,
+ LiveOutVec &LiveOuts) const {
+ const TargetRegisterInfo *TRI = AP.MF->getSubtarget().getRegisterInfo();
+ if (MOI->isImm()) {
+ switch (MOI->getImm()) {
+ default:
+ llvm_unreachable("Unrecognized operand type.");
+ case StackMaps::DirectMemRefOp: {
+ auto &DL = AP.MF->getDataLayout();
+
+ unsigned Size = DL.getPointerSizeInBits();
+ assert((Size % 8) == 0 && "Need pointer size in bytes.");
+ Size /= 8;
+ Register Reg = (++MOI)->getReg();
+ int64_t Imm = (++MOI)->getImm();
+ Locs.emplace_back(StackMaps::Location::Direct, Size,
+ getDwarfRegNum(Reg, TRI), Imm);
+ break;
+ }
+ case StackMaps::IndirectMemRefOp: {
+ int64_t Size = (++MOI)->getImm();
+ assert(Size > 0 && "Need a valid size for indirect memory locations.");
+ Register Reg = (++MOI)->getReg();
+ int64_t Imm = (++MOI)->getImm();
+ Locs.emplace_back(StackMaps::Location::Indirect, Size,
+ getDwarfRegNum(Reg, TRI), Imm);
+ break;
+ }
+ case StackMaps::ConstantOp: {
+ ++MOI;
+ assert(MOI->isImm() && "Expected constant operand.");
+ int64_t Imm = MOI->getImm();
+ Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, Imm);
+ break;
+ }
+ }
+ return ++MOI;
+ }
+
+ // The physical register number will ultimately be encoded as a DWARF regno.
+ // The stack map also records the size of a spill slot that can hold the
+ // register content. (The runtime can track the actual size of the data type
+ // if it needs to.)
+ if (MOI->isReg()) {
+ // Skip implicit registers (this includes our scratch registers)
+ if (MOI->isImplicit())
+ return ++MOI;
+
+ assert(Register::isPhysicalRegister(MOI->getReg()) &&
+ "Virtreg operands should have been rewritten before now.");
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(MOI->getReg());
+ assert(!MOI->getSubReg() && "Physical subreg still around.");
+
+ unsigned Offset = 0;
+ unsigned DwarfRegNum = getDwarfRegNum(MOI->getReg(), TRI);
+ unsigned LLVMRegNum = *TRI->getLLVMRegNum(DwarfRegNum, false);
+ unsigned SubRegIdx = TRI->getSubRegIndex(LLVMRegNum, MOI->getReg());
+ if (SubRegIdx)
+ Offset = TRI->getSubRegIdxOffset(SubRegIdx);
+
+ Locs.emplace_back(Location::Register, TRI->getSpillSize(*RC),
+ DwarfRegNum, Offset);
+ return ++MOI;
+ }
+
+ if (MOI->isRegLiveOut())
+ LiveOuts = parseRegisterLiveOutMask(MOI->getRegLiveOut());
+
+ return ++MOI;
+}
+
+void StackMaps::print(raw_ostream &OS) {
+ const TargetRegisterInfo *TRI =
+ AP.MF ? AP.MF->getSubtarget().getRegisterInfo() : nullptr;
+ OS << WSMP << "callsites:\n";
+ for (const auto &CSI : CSInfos) {
+ const LocationVec &CSLocs = CSI.Locations;
+ const LiveOutVec &LiveOuts = CSI.LiveOuts;
+
+ OS << WSMP << "callsite " << CSI.ID << "\n";
+ OS << WSMP << " has " << CSLocs.size() << " locations\n";
+
+ unsigned Idx = 0;
+ for (const auto &Loc : CSLocs) {
+ OS << WSMP << "\t\tLoc " << Idx << ": ";
+ switch (Loc.Type) {
+ case Location::Unprocessed:
+ OS << "<Unprocessed operand>";
+ break;
+ case Location::Register:
+ OS << "Register ";
+ if (TRI)
+ OS << printReg(Loc.Reg, TRI);
+ else
+ OS << Loc.Reg;
+ break;
+ case Location::Direct:
+ OS << "Direct ";
+ if (TRI)
+ OS << printReg(Loc.Reg, TRI);
+ else
+ OS << Loc.Reg;
+ if (Loc.Offset)
+ OS << " + " << Loc.Offset;
+ break;
+ case Location::Indirect:
+ OS << "Indirect ";
+ if (TRI)
+ OS << printReg(Loc.Reg, TRI);
+ else
+ OS << Loc.Reg;
+ OS << "+" << Loc.Offset;
+ break;
+ case Location::Constant:
+ OS << "Constant " << Loc.Offset;
+ break;
+ case Location::ConstantIndex:
+ OS << "Constant Index " << Loc.Offset;
+ break;
+ }
+ OS << "\t[encoding: .byte " << Loc.Type << ", .byte 0"
+ << ", .short " << Loc.Size << ", .short " << Loc.Reg << ", .short 0"
+ << ", .int " << Loc.Offset << "]\n";
+ Idx++;
+ }
+
+ OS << WSMP << "\thas " << LiveOuts.size() << " live-out registers\n";
+
+ Idx = 0;
+ for (const auto &LO : LiveOuts) {
+ OS << WSMP << "\t\tLO " << Idx << ": ";
+ if (TRI)
+ OS << printReg(LO.Reg, TRI);
+ else
+ OS << LO.Reg;
+ OS << "\t[encoding: .short " << LO.DwarfRegNum << ", .byte 0, .byte "
+ << LO.Size << "]\n";
+ Idx++;
+ }
+ }
+}
+
+/// Create a live-out register record for the given register Reg.
+StackMaps::LiveOutReg
+StackMaps::createLiveOutReg(unsigned Reg, const TargetRegisterInfo *TRI) const {
+ unsigned DwarfRegNum = getDwarfRegNum(Reg, TRI);
+ unsigned Size = TRI->getSpillSize(*TRI->getMinimalPhysRegClass(Reg));
+ return LiveOutReg(Reg, DwarfRegNum, Size);
+}
+
+/// Parse the register live-out mask and return a vector of live-out registers
+/// that need to be recorded in the stackmap.
+StackMaps::LiveOutVec
+StackMaps::parseRegisterLiveOutMask(const uint32_t *Mask) const {
+ assert(Mask && "No register mask specified");
+ const TargetRegisterInfo *TRI = AP.MF->getSubtarget().getRegisterInfo();
+ LiveOutVec LiveOuts;
+
+ // Create a LiveOutReg for each bit that is set in the register mask.
+ for (unsigned Reg = 0, NumRegs = TRI->getNumRegs(); Reg != NumRegs; ++Reg)
+ if ((Mask[Reg / 32] >> Reg % 32) & 1)
+ LiveOuts.push_back(createLiveOutReg(Reg, TRI));
+
+ // We don't need to keep track of a register if its super-register is already
+ // in the list. Merge entries that refer to the same dwarf register and use
+ // the maximum size that needs to be spilled.
+
+ llvm::sort(LiveOuts, [](const LiveOutReg &LHS, const LiveOutReg &RHS) {
+ // Only sort by the dwarf register number.
+ return LHS.DwarfRegNum < RHS.DwarfRegNum;
+ });
+
+ for (auto I = LiveOuts.begin(), E = LiveOuts.end(); I != E; ++I) {
+ for (auto II = std::next(I); II != E; ++II) {
+ if (I->DwarfRegNum != II->DwarfRegNum) {
+ // Skip all the now invalid entries.
+ I = --II;
+ break;
+ }
+ I->Size = std::max(I->Size, II->Size);
+ if (TRI->isSuperRegister(I->Reg, II->Reg))
+ I->Reg = II->Reg;
+ II->Reg = 0; // mark for deletion.
+ }
+ }
+
+ LiveOuts.erase(
+ llvm::remove_if(LiveOuts,
+ [](const LiveOutReg &LO) { return LO.Reg == 0; }),
+ LiveOuts.end());
+
+ return LiveOuts;
+}
+
+void StackMaps::recordStackMapOpers(const MachineInstr &MI, uint64_t ID,
+ MachineInstr::const_mop_iterator MOI,
+ MachineInstr::const_mop_iterator MOE,
+ bool recordResult) {
+ MCContext &OutContext = AP.OutStreamer->getContext();
+ MCSymbol *MILabel = OutContext.createTempSymbol();
+ AP.OutStreamer->EmitLabel(MILabel);
+
+ LocationVec Locations;
+ LiveOutVec LiveOuts;
+
+ if (recordResult) {
+ assert(PatchPointOpers(&MI).hasDef() && "Stackmap has no return value.");
+ parseOperand(MI.operands_begin(), std::next(MI.operands_begin()), Locations,
+ LiveOuts);
+ }
+
+ // Parse operands.
+ while (MOI != MOE) {
+ MOI = parseOperand(MOI, MOE, Locations, LiveOuts);
+ }
+
+ // Move large constants into the constant pool.
+ for (auto &Loc : Locations) {
+ // Constants are encoded as sign-extended integers.
+ // -1 is directly encoded as .long 0xFFFFFFFF with no constant pool.
+ if (Loc.Type == Location::Constant && !isInt<32>(Loc.Offset)) {
+ Loc.Type = Location::ConstantIndex;
+ // ConstPool is intentionally a MapVector of 'uint64_t's (as
+ // opposed to 'int64_t's). We should never be in a situation
+ // where we have to insert either the tombstone or the empty
+ // keys into a map, and for a DenseMap<uint64_t, T> these are
+ // (uint64_t)0 and (uint64_t)-1. They can be and are
+ // represented using 32 bit integers.
+ assert((uint64_t)Loc.Offset != DenseMapInfo<uint64_t>::getEmptyKey() &&
+ (uint64_t)Loc.Offset !=
+ DenseMapInfo<uint64_t>::getTombstoneKey() &&
+ "empty and tombstone keys should fit in 32 bits!");
+ auto Result = ConstPool.insert(std::make_pair(Loc.Offset, Loc.Offset));
+ Loc.Offset = Result.first - ConstPool.begin();
+ }
+ }
+
+ // Create an expression to calculate the offset of the callsite from function
+ // entry.
+ const MCExpr *CSOffsetExpr = MCBinaryExpr::createSub(
+ MCSymbolRefExpr::create(MILabel, OutContext),
+ MCSymbolRefExpr::create(AP.CurrentFnSymForSize, OutContext), OutContext);
+
+ CSInfos.emplace_back(CSOffsetExpr, ID, std::move(Locations),
+ std::move(LiveOuts));
+
+ // Record the stack size of the current function and update callsite count.
+ const MachineFrameInfo &MFI = AP.MF->getFrameInfo();
+ const TargetRegisterInfo *RegInfo = AP.MF->getSubtarget().getRegisterInfo();
+ bool HasDynamicFrameSize =
+ MFI.hasVarSizedObjects() || RegInfo->needsStackRealignment(*(AP.MF));
+ uint64_t FrameSize = HasDynamicFrameSize ? UINT64_MAX : MFI.getStackSize();
+
+ auto CurrentIt = FnInfos.find(AP.CurrentFnSym);
+ if (CurrentIt != FnInfos.end())
+ CurrentIt->second.RecordCount++;
+ else
+ FnInfos.insert(std::make_pair(AP.CurrentFnSym, FunctionInfo(FrameSize)));
+}
+
+void StackMaps::recordStackMap(const MachineInstr &MI) {
+ assert(MI.getOpcode() == TargetOpcode::STACKMAP && "expected stackmap");
+
+ StackMapOpers opers(&MI);
+ const int64_t ID = MI.getOperand(PatchPointOpers::IDPos).getImm();
+ recordStackMapOpers(MI, ID, std::next(MI.operands_begin(), opers.getVarIdx()),
+ MI.operands_end());
+}
+
+void StackMaps::recordPatchPoint(const MachineInstr &MI) {
+ assert(MI.getOpcode() == TargetOpcode::PATCHPOINT && "expected patchpoint");
+
+ PatchPointOpers opers(&MI);
+ const int64_t ID = opers.getID();
+ auto MOI = std::next(MI.operands_begin(), opers.getStackMapStartIdx());
+ recordStackMapOpers(MI, ID, MOI, MI.operands_end(),
+ opers.isAnyReg() && opers.hasDef());
+
+#ifndef NDEBUG
+ // verify anyregcc
+ auto &Locations = CSInfos.back().Locations;
+ if (opers.isAnyReg()) {
+ unsigned NArgs = opers.getNumCallArgs();
+ for (unsigned i = 0, e = (opers.hasDef() ? NArgs + 1 : NArgs); i != e; ++i)
+ assert(Locations[i].Type == Location::Register &&
+ "anyreg arg must be in reg.");
+ }
+#endif
+}
+
+void StackMaps::recordStatepoint(const MachineInstr &MI) {
+ assert(MI.getOpcode() == TargetOpcode::STATEPOINT && "expected statepoint");
+
+ StatepointOpers opers(&MI);
+ // Record all the deopt and gc operands (they're contiguous and run from the
+ // initial index to the end of the operand list)
+ const unsigned StartIdx = opers.getVarIdx();
+ recordStackMapOpers(MI, opers.getID(), MI.operands_begin() + StartIdx,
+ MI.operands_end(), false);
+}
+
+/// Emit the stackmap header.
+///
+/// Header {
+/// uint8 : Stack Map Version (currently 2)
+/// uint8 : Reserved (expected to be 0)
+/// uint16 : Reserved (expected to be 0)
+/// }
+/// uint32 : NumFunctions
+/// uint32 : NumConstants
+/// uint32 : NumRecords
+void StackMaps::emitStackmapHeader(MCStreamer &OS) {
+ // Header.
+ OS.EmitIntValue(StackMapVersion, 1); // Version.
+ OS.EmitIntValue(0, 1); // Reserved.
+ OS.EmitIntValue(0, 2); // Reserved.
+
+ // Num functions.
+ LLVM_DEBUG(dbgs() << WSMP << "#functions = " << FnInfos.size() << '\n');
+ OS.EmitIntValue(FnInfos.size(), 4);
+ // Num constants.
+ LLVM_DEBUG(dbgs() << WSMP << "#constants = " << ConstPool.size() << '\n');
+ OS.EmitIntValue(ConstPool.size(), 4);
+ // Num callsites.
+ LLVM_DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << '\n');
+ OS.EmitIntValue(CSInfos.size(), 4);
+}
+
+/// Emit the function frame record for each function.
+///
+/// StkSizeRecord[NumFunctions] {
+/// uint64 : Function Address
+/// uint64 : Stack Size
+/// uint64 : Record Count
+/// }
+void StackMaps::emitFunctionFrameRecords(MCStreamer &OS) {
+ // Function Frame records.
+ LLVM_DEBUG(dbgs() << WSMP << "functions:\n");
+ for (auto const &FR : FnInfos) {
+ LLVM_DEBUG(dbgs() << WSMP << "function addr: " << FR.first
+ << " frame size: " << FR.second.StackSize
+ << " callsite count: " << FR.second.RecordCount << '\n');
+ OS.EmitSymbolValue(FR.first, 8);
+ OS.EmitIntValue(FR.second.StackSize, 8);
+ OS.EmitIntValue(FR.second.RecordCount, 8);
+ }
+}
+
+/// Emit the constant pool.
+///
+/// int64 : Constants[NumConstants]
+void StackMaps::emitConstantPoolEntries(MCStreamer &OS) {
+ // Constant pool entries.
+ LLVM_DEBUG(dbgs() << WSMP << "constants:\n");
+ for (const auto &ConstEntry : ConstPool) {
+ LLVM_DEBUG(dbgs() << WSMP << ConstEntry.second << '\n');
+ OS.EmitIntValue(ConstEntry.second, 8);
+ }
+}
+
+/// Emit the callsite info for each callsite.
+///
+/// StkMapRecord[NumRecords] {
+/// uint64 : PatchPoint ID
+/// uint32 : Instruction Offset
+/// uint16 : Reserved (record flags)
+/// uint16 : NumLocations
+/// Location[NumLocations] {
+/// uint8 : Register | Direct | Indirect | Constant | ConstantIndex
+/// uint8 : Size in Bytes
+/// uint16 : Dwarf RegNum
+/// int32 : Offset
+/// }
+/// uint16 : Padding
+/// uint16 : NumLiveOuts
+/// LiveOuts[NumLiveOuts] {
+/// uint16 : Dwarf RegNum
+/// uint8 : Reserved
+/// uint8 : Size in Bytes
+/// }
+/// uint32 : Padding (only if required to align to 8 byte)
+/// }
+///
+/// Location Encoding, Type, Value:
+/// 0x1, Register, Reg (value in register)
+/// 0x2, Direct, Reg + Offset (frame index)
+/// 0x3, Indirect, [Reg + Offset] (spilled value)
+/// 0x4, Constant, Offset (small constant)
+/// 0x5, ConstIndex, Constants[Offset] (large constant)
+void StackMaps::emitCallsiteEntries(MCStreamer &OS) {
+ LLVM_DEBUG(print(dbgs()));
+ // Callsite entries.
+ for (const auto &CSI : CSInfos) {
+ const LocationVec &CSLocs = CSI.Locations;
+ const LiveOutVec &LiveOuts = CSI.LiveOuts;
+
+ // Verify stack map entry. It's better to communicate a problem to the
+ // runtime than crash in case of in-process compilation. Currently, we do
+ // simple overflow checks, but we may eventually communicate other
+ // compilation errors this way.
+ if (CSLocs.size() > UINT16_MAX || LiveOuts.size() > UINT16_MAX) {
+ OS.EmitIntValue(UINT64_MAX, 8); // Invalid ID.
+ OS.EmitValue(CSI.CSOffsetExpr, 4);
+ OS.EmitIntValue(0, 2); // Reserved.
+ OS.EmitIntValue(0, 2); // 0 locations.
+ OS.EmitIntValue(0, 2); // padding.
+ OS.EmitIntValue(0, 2); // 0 live-out registers.
+ OS.EmitIntValue(0, 4); // padding.
+ continue;
+ }
+
+ OS.EmitIntValue(CSI.ID, 8);
+ OS.EmitValue(CSI.CSOffsetExpr, 4);
+
+ // Reserved for flags.
+ OS.EmitIntValue(0, 2);
+ OS.EmitIntValue(CSLocs.size(), 2);
+
+ for (const auto &Loc : CSLocs) {
+ OS.EmitIntValue(Loc.Type, 1);
+ OS.EmitIntValue(0, 1); // Reserved
+ OS.EmitIntValue(Loc.Size, 2);
+ OS.EmitIntValue(Loc.Reg, 2);
+ OS.EmitIntValue(0, 2); // Reserved
+ OS.EmitIntValue(Loc.Offset, 4);
+ }
+
+ // Emit alignment to 8 byte.
+ OS.EmitValueToAlignment(8);
+
+ // Num live-out registers and padding to align to 4 byte.
+ OS.EmitIntValue(0, 2);
+ OS.EmitIntValue(LiveOuts.size(), 2);
+
+ for (const auto &LO : LiveOuts) {
+ OS.EmitIntValue(LO.DwarfRegNum, 2);
+ OS.EmitIntValue(0, 1);
+ OS.EmitIntValue(LO.Size, 1);
+ }
+ // Emit alignment to 8 byte.
+ OS.EmitValueToAlignment(8);
+ }
+}
+
+/// Serialize the stackmap data.
+void StackMaps::serializeToStackMapSection() {
+ (void)WSMP;
+ // Bail out if there's no stack map data.
+ assert((!CSInfos.empty() || ConstPool.empty()) &&
+ "Expected empty constant pool too!");
+ assert((!CSInfos.empty() || FnInfos.empty()) &&
+ "Expected empty function record too!");
+ if (CSInfos.empty())
+ return;
+
+ MCContext &OutContext = AP.OutStreamer->getContext();
+ MCStreamer &OS = *AP.OutStreamer;
+
+ // Create the section.
+ MCSection *StackMapSection =
+ OutContext.getObjectFileInfo()->getStackMapSection();
+ OS.SwitchSection(StackMapSection);
+
+ // Emit a dummy symbol to force section inclusion.
+ OS.EmitLabel(OutContext.getOrCreateSymbol(Twine("__LLVM_StackMaps")));
+
+ // Serialize data.
+ LLVM_DEBUG(dbgs() << "********** Stack Map Output **********\n");
+ emitStackmapHeader(OS);
+ emitFunctionFrameRecords(OS);
+ emitConstantPoolEntries(OS);
+ emitCallsiteEntries(OS);
+ OS.AddBlankLine();
+
+ // Clean up.
+ CSInfos.clear();
+ ConstPool.clear();
+}
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