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Diffstat (limited to 'contrib/llvm-project/llvm/lib/CodeGen/StackMaps.cpp')
-rw-r--r-- | contrib/llvm-project/llvm/lib/CodeGen/StackMaps.cpp | 740 |
1 files changed, 740 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/CodeGen/StackMaps.cpp b/contrib/llvm-project/llvm/lib/CodeGen/StackMaps.cpp new file mode 100644 index 000000000000..36e8f129ea15 --- /dev/null +++ b/contrib/llvm-project/llvm/lib/CodeGen/StackMaps.cpp @@ -0,0 +1,740 @@ +//===- 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: "; + +static uint64_t getConstMetaVal(const MachineInstr &MI, unsigned Idx) { + assert(MI.getOperand(Idx).isImm() && + MI.getOperand(Idx).getImm() == StackMaps::ConstantOp); + const auto &MO = MI.getOperand(Idx + 1); + assert(MO.isImm()); + return MO.getImm(); +} + +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; +} + +unsigned StatepointOpers::getNumGcMapEntriesIdx() { + // Take index of num of allocas and skip all allocas records. + unsigned CurIdx = getNumAllocaIdx(); + unsigned NumAllocas = getConstMetaVal(*MI, CurIdx - 1); + CurIdx++; + while (NumAllocas--) + CurIdx = StackMaps::getNextMetaArgIdx(MI, CurIdx); + return CurIdx + 1; // skip <StackMaps::ConstantOp> +} + +unsigned StatepointOpers::getNumAllocaIdx() { + // Take index of num of gc ptrs and skip all gc ptr records. + unsigned CurIdx = getNumGCPtrIdx(); + unsigned NumGCPtrs = getConstMetaVal(*MI, CurIdx - 1); + CurIdx++; + while (NumGCPtrs--) + CurIdx = StackMaps::getNextMetaArgIdx(MI, CurIdx); + return CurIdx + 1; // skip <StackMaps::ConstantOp> +} + +unsigned StatepointOpers::getNumGCPtrIdx() { + // Take index of num of deopt args and skip all deopt records. + unsigned CurIdx = getNumDeoptArgsIdx(); + unsigned NumDeoptArgs = getConstMetaVal(*MI, CurIdx - 1); + CurIdx++; + while (NumDeoptArgs--) { + CurIdx = StackMaps::getNextMetaArgIdx(MI, CurIdx); + } + return CurIdx + 1; // skip <StackMaps::ConstantOp> +} + +int StatepointOpers::getFirstGCPtrIdx() { + unsigned NumGCPtrsIdx = getNumGCPtrIdx(); + unsigned NumGCPtrs = getConstMetaVal(*MI, NumGCPtrsIdx - 1); + if (NumGCPtrs == 0) + return -1; + ++NumGCPtrsIdx; // skip <num gc ptrs> + assert(NumGCPtrsIdx < MI->getNumOperands()); + return (int)NumGCPtrsIdx; +} + +unsigned StatepointOpers::getGCPointerMap( + SmallVectorImpl<std::pair<unsigned, unsigned>> &GCMap) { + unsigned CurIdx = getNumGcMapEntriesIdx(); + unsigned GCMapSize = getConstMetaVal(*MI, CurIdx - 1); + CurIdx++; + for (unsigned N = 0; N < GCMapSize; ++N) { + unsigned B = MI->getOperand(CurIdx++).getImm(); + unsigned D = MI->getOperand(CurIdx++).getImm(); + GCMap.push_back(std::make_pair(B, D)); + } + + return GCMapSize; +} + +StackMaps::StackMaps(AsmPrinter &AP) : AP(AP) { + if (StackMapVersion != 3) + llvm_unreachable("Unsupported stackmap version!"); +} + +unsigned StackMaps::getNextMetaArgIdx(const MachineInstr *MI, unsigned CurIdx) { + assert(CurIdx < MI->getNumOperands() && "Bad meta arg index"); + const auto &MO = MI->getOperand(CurIdx); + if (MO.isImm()) { + switch (MO.getImm()) { + default: + llvm_unreachable("Unrecognized operand type."); + case StackMaps::DirectMemRefOp: + CurIdx += 2; + break; + case StackMaps::IndirectMemRefOp: + CurIdx += 3; + break; + case StackMaps::ConstantOp: + ++CurIdx; + break; + } + } + ++CurIdx; + assert(CurIdx < MI->getNumOperands() && "points past operand list"); + return CurIdx; +} + +/// 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; + + if (MOI->isUndef()) { + // Record `undef` register as constant. Use same value as ISel uses. + Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, 0xFEFEFEFE); + 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. + } + } + + llvm::erase_if(LiveOuts, [](const LiveOutReg &LO) { return LO.Reg == 0; }); + + return LiveOuts; +} + +// See statepoint MI format description in StatepointOpers' class comment +// in include/llvm/CodeGen/StackMaps.h +void StackMaps::parseStatepointOpers(const MachineInstr &MI, + MachineInstr::const_mop_iterator MOI, + MachineInstr::const_mop_iterator MOE, + LocationVec &Locations, + LiveOutVec &LiveOuts) { + LLVM_DEBUG(dbgs() << "record statepoint : " << MI << "\n"); + StatepointOpers SO(&MI); + MOI = parseOperand(MOI, MOE, Locations, LiveOuts); // CC + MOI = parseOperand(MOI, MOE, Locations, LiveOuts); // Flags + MOI = parseOperand(MOI, MOE, Locations, LiveOuts); // Num Deopts + + // Record Deopt Args. + unsigned NumDeoptArgs = Locations.back().Offset; + assert(Locations.back().Type == Location::Constant); + assert(NumDeoptArgs == SO.getNumDeoptArgs()); + + while (NumDeoptArgs--) + MOI = parseOperand(MOI, MOE, Locations, LiveOuts); + + // Record gc base/derived pairs + assert(MOI->isImm() && MOI->getImm() == StackMaps::ConstantOp); + ++MOI; + assert(MOI->isImm()); + unsigned NumGCPointers = MOI->getImm(); + ++MOI; + if (NumGCPointers) { + // Map logical index of GC ptr to MI operand index. + SmallVector<unsigned, 8> GCPtrIndices; + unsigned GCPtrIdx = (unsigned)SO.getFirstGCPtrIdx(); + assert((int)GCPtrIdx != -1); + assert(MOI - MI.operands_begin() == GCPtrIdx + 0LL); + while (NumGCPointers--) { + GCPtrIndices.push_back(GCPtrIdx); + GCPtrIdx = StackMaps::getNextMetaArgIdx(&MI, GCPtrIdx); + } + + SmallVector<std::pair<unsigned, unsigned>, 8> GCPairs; + unsigned NumGCPairs = SO.getGCPointerMap(GCPairs); + (void)NumGCPairs; + LLVM_DEBUG(dbgs() << "NumGCPairs = " << NumGCPairs << "\n"); + + auto MOB = MI.operands_begin(); + for (auto &P : GCPairs) { + assert(P.first < GCPtrIndices.size() && "base pointer index not found"); + assert(P.second < GCPtrIndices.size() && + "derived pointer index not found"); + unsigned BaseIdx = GCPtrIndices[P.first]; + unsigned DerivedIdx = GCPtrIndices[P.second]; + LLVM_DEBUG(dbgs() << "Base : " << BaseIdx << " Derived : " << DerivedIdx + << "\n"); + (void)parseOperand(MOB + BaseIdx, MOE, Locations, LiveOuts); + (void)parseOperand(MOB + DerivedIdx, MOE, Locations, LiveOuts); + } + + MOI = MOB + GCPtrIdx; + } + + // Record gc allocas + assert(MOI < MOE); + assert(MOI->isImm() && MOI->getImm() == StackMaps::ConstantOp); + ++MOI; + unsigned NumAllocas = MOI->getImm(); + ++MOI; + while (NumAllocas--) { + MOI = parseOperand(MOI, MOE, Locations, LiveOuts); + assert(MOI < MOE); + } +} + +void StackMaps::recordStackMapOpers(const MCSymbol &MILabel, + const MachineInstr &MI, uint64_t ID, + MachineInstr::const_mop_iterator MOI, + MachineInstr::const_mop_iterator MOE, + bool recordResult) { + MCContext &OutContext = AP.OutStreamer->getContext(); + + 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. + if (MI.getOpcode() == TargetOpcode::STATEPOINT) + parseStatepointOpers(MI, MOI, MOE, Locations, LiveOuts); + else + 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->hasStackRealignment(*(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 MCSymbol &L, const MachineInstr &MI) { + assert(MI.getOpcode() == TargetOpcode::STACKMAP && "expected stackmap"); + + StackMapOpers opers(&MI); + const int64_t ID = MI.getOperand(PatchPointOpers::IDPos).getImm(); + recordStackMapOpers(L, MI, ID, std::next(MI.operands_begin(), + opers.getVarIdx()), + MI.operands_end()); +} + +void StackMaps::recordPatchPoint(const MCSymbol &L, 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(L, 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 MCSymbol &L, const MachineInstr &MI) { + assert(MI.getOpcode() == TargetOpcode::STATEPOINT && "expected statepoint"); + + StatepointOpers opers(&MI); + const unsigned StartIdx = opers.getVarIdx(); + recordStackMapOpers(L, MI, opers.getID(), MI.operands_begin() + StartIdx, + MI.operands_end(), false); +} + +/// Emit the stackmap header. +/// +/// Header { +/// uint8 : Stack Map Version (currently 3) +/// 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.emitInt16(0); // Reserved. + + // Num functions. + LLVM_DEBUG(dbgs() << WSMP << "#functions = " << FnInfos.size() << '\n'); + OS.emitInt32(FnInfos.size()); + // Num constants. + LLVM_DEBUG(dbgs() << WSMP << "#constants = " << ConstPool.size() << '\n'); + OS.emitInt32(ConstPool.size()); + // Num callsites. + LLVM_DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << '\n'); + OS.emitInt32(CSInfos.size()); +} + +/// 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.emitInt16(0); // Reserved. + OS.emitInt16(0); // 0 locations. + OS.emitInt16(0); // padding. + OS.emitInt16(0); // 0 live-out registers. + OS.emitInt32(0); // padding. + continue; + } + + OS.emitIntValue(CSI.ID, 8); + OS.emitValue(CSI.CSOffsetExpr, 4); + + // Reserved for flags. + OS.emitInt16(0); + OS.emitInt16(CSLocs.size()); + + for (const auto &Loc : CSLocs) { + OS.emitIntValue(Loc.Type, 1); + OS.emitIntValue(0, 1); // Reserved + OS.emitInt16(Loc.Size); + OS.emitInt16(Loc.Reg); + OS.emitInt16(0); // Reserved + OS.emitInt32(Loc.Offset); + } + + // Emit alignment to 8 byte. + OS.emitValueToAlignment(8); + + // Num live-out registers and padding to align to 4 byte. + OS.emitInt16(0); + OS.emitInt16(LiveOuts.size()); + + for (const auto &LO : LiveOuts) { + OS.emitInt16(LO.DwarfRegNum); + 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(); +} |