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Diffstat (limited to 'contrib/llvm-project/llvm/lib/MC/MCWin64EH.cpp')
| -rw-r--r-- | contrib/llvm-project/llvm/lib/MC/MCWin64EH.cpp | 680 |
1 files changed, 680 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/MC/MCWin64EH.cpp b/contrib/llvm-project/llvm/lib/MC/MCWin64EH.cpp new file mode 100644 index 000000000000..4e9a29667097 --- /dev/null +++ b/contrib/llvm-project/llvm/lib/MC/MCWin64EH.cpp @@ -0,0 +1,680 @@ +//===- lib/MC/MCWin64EH.cpp - MCWin64EH implementation --------------------===// +// +// 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/MC/MCWin64EH.h" +#include "llvm/ADT/Twine.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCObjectFileInfo.h" +#include "llvm/MC/MCObjectStreamer.h" +#include "llvm/MC/MCSectionCOFF.h" +#include "llvm/MC/MCStreamer.h" +#include "llvm/MC/MCSymbol.h" +#include "llvm/Support/Win64EH.h" + +using namespace llvm; + +// NOTE: All relocations generated here are 4-byte image-relative. + +static uint8_t CountOfUnwindCodes(std::vector<WinEH::Instruction> &Insns) { + uint8_t Count = 0; + for (const auto &I : Insns) { + switch (static_cast<Win64EH::UnwindOpcodes>(I.Operation)) { + default: + llvm_unreachable("Unsupported unwind code"); + case Win64EH::UOP_PushNonVol: + case Win64EH::UOP_AllocSmall: + case Win64EH::UOP_SetFPReg: + case Win64EH::UOP_PushMachFrame: + Count += 1; + break; + case Win64EH::UOP_SaveNonVol: + case Win64EH::UOP_SaveXMM128: + Count += 2; + break; + case Win64EH::UOP_SaveNonVolBig: + case Win64EH::UOP_SaveXMM128Big: + Count += 3; + break; + case Win64EH::UOP_AllocLarge: + Count += (I.Offset > 512 * 1024 - 8) ? 3 : 2; + break; + } + } + return Count; +} + +static void EmitAbsDifference(MCStreamer &Streamer, const MCSymbol *LHS, + const MCSymbol *RHS) { + MCContext &Context = Streamer.getContext(); + const MCExpr *Diff = + MCBinaryExpr::createSub(MCSymbolRefExpr::create(LHS, Context), + MCSymbolRefExpr::create(RHS, Context), Context); + Streamer.EmitValue(Diff, 1); +} + +static void EmitUnwindCode(MCStreamer &streamer, const MCSymbol *begin, + WinEH::Instruction &inst) { + uint8_t b2; + uint16_t w; + b2 = (inst.Operation & 0x0F); + switch (static_cast<Win64EH::UnwindOpcodes>(inst.Operation)) { + default: + llvm_unreachable("Unsupported unwind code"); + case Win64EH::UOP_PushNonVol: + EmitAbsDifference(streamer, inst.Label, begin); + b2 |= (inst.Register & 0x0F) << 4; + streamer.EmitIntValue(b2, 1); + break; + case Win64EH::UOP_AllocLarge: + EmitAbsDifference(streamer, inst.Label, begin); + if (inst.Offset > 512 * 1024 - 8) { + b2 |= 0x10; + streamer.EmitIntValue(b2, 1); + w = inst.Offset & 0xFFF8; + streamer.EmitIntValue(w, 2); + w = inst.Offset >> 16; + } else { + streamer.EmitIntValue(b2, 1); + w = inst.Offset >> 3; + } + streamer.EmitIntValue(w, 2); + break; + case Win64EH::UOP_AllocSmall: + b2 |= (((inst.Offset - 8) >> 3) & 0x0F) << 4; + EmitAbsDifference(streamer, inst.Label, begin); + streamer.EmitIntValue(b2, 1); + break; + case Win64EH::UOP_SetFPReg: + EmitAbsDifference(streamer, inst.Label, begin); + streamer.EmitIntValue(b2, 1); + break; + case Win64EH::UOP_SaveNonVol: + case Win64EH::UOP_SaveXMM128: + b2 |= (inst.Register & 0x0F) << 4; + EmitAbsDifference(streamer, inst.Label, begin); + streamer.EmitIntValue(b2, 1); + w = inst.Offset >> 3; + if (inst.Operation == Win64EH::UOP_SaveXMM128) + w >>= 1; + streamer.EmitIntValue(w, 2); + break; + case Win64EH::UOP_SaveNonVolBig: + case Win64EH::UOP_SaveXMM128Big: + b2 |= (inst.Register & 0x0F) << 4; + EmitAbsDifference(streamer, inst.Label, begin); + streamer.EmitIntValue(b2, 1); + if (inst.Operation == Win64EH::UOP_SaveXMM128Big) + w = inst.Offset & 0xFFF0; + else + w = inst.Offset & 0xFFF8; + streamer.EmitIntValue(w, 2); + w = inst.Offset >> 16; + streamer.EmitIntValue(w, 2); + break; + case Win64EH::UOP_PushMachFrame: + if (inst.Offset == 1) + b2 |= 0x10; + EmitAbsDifference(streamer, inst.Label, begin); + streamer.EmitIntValue(b2, 1); + break; + } +} + +static void EmitSymbolRefWithOfs(MCStreamer &streamer, + const MCSymbol *Base, + const MCSymbol *Other) { + MCContext &Context = streamer.getContext(); + const MCSymbolRefExpr *BaseRef = MCSymbolRefExpr::create(Base, Context); + const MCSymbolRefExpr *OtherRef = MCSymbolRefExpr::create(Other, Context); + const MCExpr *Ofs = MCBinaryExpr::createSub(OtherRef, BaseRef, Context); + const MCSymbolRefExpr *BaseRefRel = MCSymbolRefExpr::create(Base, + MCSymbolRefExpr::VK_COFF_IMGREL32, + Context); + streamer.EmitValue(MCBinaryExpr::createAdd(BaseRefRel, Ofs, Context), 4); +} + +static void EmitRuntimeFunction(MCStreamer &streamer, + const WinEH::FrameInfo *info) { + MCContext &context = streamer.getContext(); + + streamer.EmitValueToAlignment(4); + EmitSymbolRefWithOfs(streamer, info->Function, info->Begin); + EmitSymbolRefWithOfs(streamer, info->Function, info->End); + streamer.EmitValue(MCSymbolRefExpr::create(info->Symbol, + MCSymbolRefExpr::VK_COFF_IMGREL32, + context), 4); +} + +static void EmitUnwindInfo(MCStreamer &streamer, WinEH::FrameInfo *info) { + // If this UNWIND_INFO already has a symbol, it's already been emitted. + if (info->Symbol) + return; + + MCContext &context = streamer.getContext(); + MCSymbol *Label = context.createTempSymbol(); + + streamer.EmitValueToAlignment(4); + streamer.EmitLabel(Label); + info->Symbol = Label; + + // Upper 3 bits are the version number (currently 1). + uint8_t flags = 0x01; + if (info->ChainedParent) + flags |= Win64EH::UNW_ChainInfo << 3; + else { + if (info->HandlesUnwind) + flags |= Win64EH::UNW_TerminateHandler << 3; + if (info->HandlesExceptions) + flags |= Win64EH::UNW_ExceptionHandler << 3; + } + streamer.EmitIntValue(flags, 1); + + if (info->PrologEnd) + EmitAbsDifference(streamer, info->PrologEnd, info->Begin); + else + streamer.EmitIntValue(0, 1); + + uint8_t numCodes = CountOfUnwindCodes(info->Instructions); + streamer.EmitIntValue(numCodes, 1); + + uint8_t frame = 0; + if (info->LastFrameInst >= 0) { + WinEH::Instruction &frameInst = info->Instructions[info->LastFrameInst]; + assert(frameInst.Operation == Win64EH::UOP_SetFPReg); + frame = (frameInst.Register & 0x0F) | (frameInst.Offset & 0xF0); + } + streamer.EmitIntValue(frame, 1); + + // Emit unwind instructions (in reverse order). + uint8_t numInst = info->Instructions.size(); + for (uint8_t c = 0; c < numInst; ++c) { + WinEH::Instruction inst = info->Instructions.back(); + info->Instructions.pop_back(); + EmitUnwindCode(streamer, info->Begin, inst); + } + + // For alignment purposes, the instruction array will always have an even + // number of entries, with the final entry potentially unused (in which case + // the array will be one longer than indicated by the count of unwind codes + // field). + if (numCodes & 1) { + streamer.EmitIntValue(0, 2); + } + + if (flags & (Win64EH::UNW_ChainInfo << 3)) + EmitRuntimeFunction(streamer, info->ChainedParent); + else if (flags & + ((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3)) + streamer.EmitValue(MCSymbolRefExpr::create(info->ExceptionHandler, + MCSymbolRefExpr::VK_COFF_IMGREL32, + context), 4); + else if (numCodes == 0) { + // The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not + // a chained unwind info, if there is no handler, and if there are fewer + // than 2 slots used in the unwind code array, we have to pad to 8 bytes. + streamer.EmitIntValue(0, 4); + } +} + +void llvm::Win64EH::UnwindEmitter::Emit(MCStreamer &Streamer) const { + // Emit the unwind info structs first. + for (const auto &CFI : Streamer.getWinFrameInfos()) { + MCSection *XData = Streamer.getAssociatedXDataSection(CFI->TextSection); + Streamer.SwitchSection(XData); + ::EmitUnwindInfo(Streamer, CFI.get()); + } + + // Now emit RUNTIME_FUNCTION entries. + for (const auto &CFI : Streamer.getWinFrameInfos()) { + MCSection *PData = Streamer.getAssociatedPDataSection(CFI->TextSection); + Streamer.SwitchSection(PData); + EmitRuntimeFunction(Streamer, CFI.get()); + } +} + +void llvm::Win64EH::UnwindEmitter::EmitUnwindInfo( + MCStreamer &Streamer, WinEH::FrameInfo *info) const { + // Switch sections (the static function above is meant to be called from + // here and from Emit(). + MCSection *XData = Streamer.getAssociatedXDataSection(info->TextSection); + Streamer.SwitchSection(XData); + + ::EmitUnwindInfo(Streamer, info); +} + +static int64_t GetAbsDifference(MCStreamer &Streamer, const MCSymbol *LHS, + const MCSymbol *RHS) { + MCContext &Context = Streamer.getContext(); + const MCExpr *Diff = + MCBinaryExpr::createSub(MCSymbolRefExpr::create(LHS, Context), + MCSymbolRefExpr::create(RHS, Context), Context); + MCObjectStreamer *OS = (MCObjectStreamer *)(&Streamer); + // It should normally be possible to calculate the length of a function + // at this point, but it might not be possible in the presence of certain + // unusual constructs, like an inline asm with an alignment directive. + int64_t value; + if (!Diff->evaluateAsAbsolute(value, OS->getAssembler())) + report_fatal_error("Failed to evaluate function length in SEH unwind info"); + return value; +} + +static uint32_t +ARM64CountOfUnwindCodes(const std::vector<WinEH::Instruction> &Insns) { + uint32_t Count = 0; + for (const auto &I : Insns) { + switch (static_cast<Win64EH::UnwindOpcodes>(I.Operation)) { + default: + llvm_unreachable("Unsupported ARM64 unwind code"); + case Win64EH::UOP_AllocSmall: + Count += 1; + break; + case Win64EH::UOP_AllocMedium: + Count += 2; + break; + case Win64EH::UOP_AllocLarge: + Count += 4; + break; + case Win64EH::UOP_SaveFPLRX: + Count += 1; + break; + case Win64EH::UOP_SaveFPLR: + Count += 1; + break; + case Win64EH::UOP_SaveReg: + Count += 2; + break; + case Win64EH::UOP_SaveRegP: + Count += 2; + break; + case Win64EH::UOP_SaveRegPX: + Count += 2; + break; + case Win64EH::UOP_SaveRegX: + Count += 2; + break; + case Win64EH::UOP_SaveFReg: + Count += 2; + break; + case Win64EH::UOP_SaveFRegP: + Count += 2; + break; + case Win64EH::UOP_SaveFRegX: + Count += 2; + break; + case Win64EH::UOP_SaveFRegPX: + Count += 2; + break; + case Win64EH::UOP_SetFP: + Count += 1; + break; + case Win64EH::UOP_AddFP: + Count += 2; + break; + case Win64EH::UOP_Nop: + Count += 1; + break; + case Win64EH::UOP_End: + Count += 1; + break; + } + } + return Count; +} + +// Unwind opcode encodings and restrictions are documented at +// https://docs.microsoft.com/en-us/cpp/build/arm64-exception-handling +static void ARM64EmitUnwindCode(MCStreamer &streamer, const MCSymbol *begin, + WinEH::Instruction &inst) { + uint8_t b, reg; + switch (static_cast<Win64EH::UnwindOpcodes>(inst.Operation)) { + default: + llvm_unreachable("Unsupported ARM64 unwind code"); + case Win64EH::UOP_AllocSmall: + b = (inst.Offset >> 4) & 0x1F; + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_AllocMedium: { + uint16_t hw = (inst.Offset >> 4) & 0x7FF; + b = 0xC0; + b |= (hw >> 8); + streamer.EmitIntValue(b, 1); + b = hw & 0xFF; + streamer.EmitIntValue(b, 1); + break; + } + case Win64EH::UOP_AllocLarge: { + uint32_t w; + b = 0xE0; + streamer.EmitIntValue(b, 1); + w = inst.Offset >> 4; + b = (w & 0x00FF0000) >> 16; + streamer.EmitIntValue(b, 1); + b = (w & 0x0000FF00) >> 8; + streamer.EmitIntValue(b, 1); + b = w & 0x000000FF; + streamer.EmitIntValue(b, 1); + break; + } + case Win64EH::UOP_SetFP: + b = 0xE1; + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_AddFP: + b = 0xE2; + streamer.EmitIntValue(b, 1); + b = (inst.Offset >> 3); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_Nop: + b = 0xE3; + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveFPLRX: + b = 0x80; + b |= ((inst.Offset - 1) >> 3) & 0x3F; + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveFPLR: + b = 0x40; + b |= (inst.Offset >> 3) & 0x3F; + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveReg: + assert(inst.Register >= 19 && "Saved reg must be >= 19"); + reg = inst.Register - 19; + b = 0xD0 | ((reg & 0xC) >> 2); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x3) << 6) | (inst.Offset >> 3); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveRegX: + assert(inst.Register >= 19 && "Saved reg must be >= 19"); + reg = inst.Register - 19; + b = 0xD4 | ((reg & 0x8) >> 3); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x7) << 5) | ((inst.Offset >> 3) - 1); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveRegP: + assert(inst.Register >= 19 && "Saved registers must be >= 19"); + reg = inst.Register - 19; + b = 0xC8 | ((reg & 0xC) >> 2); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x3) << 6) | (inst.Offset >> 3); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveRegPX: + assert(inst.Register >= 19 && "Saved registers must be >= 19"); + reg = inst.Register - 19; + b = 0xCC | ((reg & 0xC) >> 2); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x3) << 6) | ((inst.Offset >> 3) - 1); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveFReg: + assert(inst.Register >= 8 && "Saved dreg must be >= 8"); + reg = inst.Register - 8; + b = 0xDC | ((reg & 0x4) >> 2); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x3) << 6) | (inst.Offset >> 3); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveFRegX: + assert(inst.Register >= 8 && "Saved dreg must be >= 8"); + reg = inst.Register - 8; + b = 0xDE; + streamer.EmitIntValue(b, 1); + b = ((reg & 0x7) << 5) | ((inst.Offset >> 3) - 1); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveFRegP: + assert(inst.Register >= 8 && "Saved dregs must be >= 8"); + reg = inst.Register - 8; + b = 0xD8 | ((reg & 0x4) >> 2); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x3) << 6) | (inst.Offset >> 3); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_SaveFRegPX: + assert(inst.Register >= 8 && "Saved dregs must be >= 8"); + reg = inst.Register - 8; + b = 0xDA | ((reg & 0x4) >> 2); + streamer.EmitIntValue(b, 1); + b = ((reg & 0x3) << 6) | ((inst.Offset >> 3) - 1); + streamer.EmitIntValue(b, 1); + break; + case Win64EH::UOP_End: + b = 0xE4; + streamer.EmitIntValue(b, 1); + break; + } +} + +// Returns the epilog symbol of an epilog with the exact same unwind code +// sequence, if it exists. Otherwise, returns nulltpr. +// EpilogInstrs - Unwind codes for the current epilog. +// Epilogs - Epilogs that potentialy match the current epilog. +static MCSymbol* +FindMatchingEpilog(const std::vector<WinEH::Instruction>& EpilogInstrs, + const std::vector<MCSymbol *>& Epilogs, + const WinEH::FrameInfo *info) { + for (auto *EpilogStart : Epilogs) { + auto InstrsIter = info->EpilogMap.find(EpilogStart); + assert(InstrsIter != info->EpilogMap.end() && + "Epilog not found in EpilogMap"); + const auto &Instrs = InstrsIter->second; + + if (Instrs.size() != EpilogInstrs.size()) + continue; + + bool Match = true; + for (unsigned i = 0; i < Instrs.size(); ++i) + if (Instrs[i].Operation != EpilogInstrs[i].Operation || + Instrs[i].Offset != EpilogInstrs[i].Offset || + Instrs[i].Register != EpilogInstrs[i].Register) { + Match = false; + break; + } + + if (Match) + return EpilogStart; + } + return nullptr; +} + +// Populate the .xdata section. The format of .xdata on ARM64 is documented at +// https://docs.microsoft.com/en-us/cpp/build/arm64-exception-handling +static void ARM64EmitUnwindInfo(MCStreamer &streamer, WinEH::FrameInfo *info) { + // If this UNWIND_INFO already has a symbol, it's already been emitted. + if (info->Symbol) + return; + + MCContext &context = streamer.getContext(); + MCSymbol *Label = context.createTempSymbol(); + + streamer.EmitValueToAlignment(4); + streamer.EmitLabel(Label); + info->Symbol = Label; + + int64_t RawFuncLength; + if (!info->FuncletOrFuncEnd) { + // FIXME: This is very wrong; we emit SEH data which covers zero bytes + // of code. But otherwise test/MC/AArch64/seh.s crashes. + RawFuncLength = 0; + } else { + // FIXME: GetAbsDifference tries to compute the length of the function + // immediately, before the whole file is emitted, but in general + // that's impossible: the size in bytes of certain assembler directives + // like .align and .fill is not known until the whole file is parsed and + // relaxations are applied. Currently, GetAbsDifference fails with a fatal + // error in that case. (We mostly don't hit this because inline assembly + // specifying those directives is rare, and we don't normally try to + // align loops on AArch64.) + // + // There are two potential approaches to delaying the computation. One, + // we could emit something like ".word (endfunc-beginfunc)/4+0x10800000", + // as long as we have some conservative estimate we could use to prove + // that we don't need to split the unwind data. Emitting the constant + // is straightforward, but there's no existing code for estimating the + // size of the function. + // + // The other approach would be to use a dedicated, relaxable fragment, + // which could grow to accommodate splitting the unwind data if + // necessary. This is more straightforward, since it automatically works + // without any new infrastructure, and it's consistent with how we handle + // relaxation in other contexts. But it would require some refactoring + // to move parts of the pdata/xdata emission into the implementation of + // a fragment. We could probably continue to encode the unwind codes + // here, but we'd have to emit the pdata, the xdata header, and the + // epilogue scopes later, since they depend on whether the we need to + // split the unwind data. + RawFuncLength = GetAbsDifference(streamer, info->FuncletOrFuncEnd, + info->Begin); + } + if (RawFuncLength > 0xFFFFF) + report_fatal_error("SEH unwind data splitting not yet implemented"); + uint32_t FuncLength = (uint32_t)RawFuncLength / 4; + uint32_t PrologCodeBytes = ARM64CountOfUnwindCodes(info->Instructions); + uint32_t TotalCodeBytes = PrologCodeBytes; + + // Process epilogs. + MapVector<MCSymbol *, uint32_t> EpilogInfo; + // Epilogs processed so far. + std::vector<MCSymbol *> AddedEpilogs; + + for (auto &I : info->EpilogMap) { + MCSymbol *EpilogStart = I.first; + auto &EpilogInstrs = I.second; + uint32_t CodeBytes = ARM64CountOfUnwindCodes(EpilogInstrs); + + MCSymbol* MatchingEpilog = + FindMatchingEpilog(EpilogInstrs, AddedEpilogs, info); + if (MatchingEpilog) { + assert(EpilogInfo.find(MatchingEpilog) != EpilogInfo.end() && + "Duplicate epilog not found"); + EpilogInfo[EpilogStart] = EpilogInfo.lookup(MatchingEpilog); + // Clear the unwind codes in the EpilogMap, so that they don't get output + // in the logic below. + EpilogInstrs.clear(); + } else { + EpilogInfo[EpilogStart] = TotalCodeBytes; + TotalCodeBytes += CodeBytes; + AddedEpilogs.push_back(EpilogStart); + } + } + + // Code Words, Epilog count, E, X, Vers, Function Length + uint32_t row1 = 0x0; + uint32_t CodeWords = TotalCodeBytes / 4; + uint32_t CodeWordsMod = TotalCodeBytes % 4; + if (CodeWordsMod) + CodeWords++; + uint32_t EpilogCount = info->EpilogMap.size(); + bool ExtensionWord = EpilogCount > 31 || TotalCodeBytes > 124; + if (!ExtensionWord) { + row1 |= (EpilogCount & 0x1F) << 22; + row1 |= (CodeWords & 0x1F) << 27; + } + // E is always 0 right now, TODO: packed epilog setup + if (info->HandlesExceptions) // X + row1 |= 1 << 20; + row1 |= FuncLength & 0x3FFFF; + streamer.EmitIntValue(row1, 4); + + // Extended Code Words, Extended Epilog Count + if (ExtensionWord) { + // FIXME: We should be able to split unwind info into multiple sections. + // FIXME: We should share epilog codes across epilogs, where possible, + // which would make this issue show up less frequently. + if (CodeWords > 0xFF || EpilogCount > 0xFFFF) + report_fatal_error("SEH unwind data splitting not yet implemented"); + uint32_t row2 = 0x0; + row2 |= (CodeWords & 0xFF) << 16; + row2 |= (EpilogCount & 0xFFFF); + streamer.EmitIntValue(row2, 4); + } + + // Epilog Start Index, Epilog Start Offset + for (auto &I : EpilogInfo) { + MCSymbol *EpilogStart = I.first; + uint32_t EpilogIndex = I.second; + uint32_t EpilogOffset = + (uint32_t)GetAbsDifference(streamer, EpilogStart, info->Begin); + if (EpilogOffset) + EpilogOffset /= 4; + uint32_t row3 = EpilogOffset; + row3 |= (EpilogIndex & 0x3FF) << 22; + streamer.EmitIntValue(row3, 4); + } + + // Emit prolog unwind instructions (in reverse order). + uint8_t numInst = info->Instructions.size(); + for (uint8_t c = 0; c < numInst; ++c) { + WinEH::Instruction inst = info->Instructions.back(); + info->Instructions.pop_back(); + ARM64EmitUnwindCode(streamer, info->Begin, inst); + } + + // Emit epilog unwind instructions + for (auto &I : info->EpilogMap) { + auto &EpilogInstrs = I.second; + for (uint32_t i = 0; i < EpilogInstrs.size(); i++) { + WinEH::Instruction inst = EpilogInstrs[i]; + ARM64EmitUnwindCode(streamer, info->Begin, inst); + } + } + + int32_t BytesMod = CodeWords * 4 - TotalCodeBytes; + assert(BytesMod >= 0); + for (int i = 0; i < BytesMod; i++) + streamer.EmitIntValue(0xE3, 1); + + if (info->HandlesExceptions) + streamer.EmitValue( + MCSymbolRefExpr::create(info->ExceptionHandler, + MCSymbolRefExpr::VK_COFF_IMGREL32, context), + 4); +} + +static void ARM64EmitRuntimeFunction(MCStreamer &streamer, + const WinEH::FrameInfo *info) { + MCContext &context = streamer.getContext(); + + streamer.EmitValueToAlignment(4); + EmitSymbolRefWithOfs(streamer, info->Function, info->Begin); + streamer.EmitValue(MCSymbolRefExpr::create(info->Symbol, + MCSymbolRefExpr::VK_COFF_IMGREL32, + context), + 4); +} + +void llvm::Win64EH::ARM64UnwindEmitter::Emit(MCStreamer &Streamer) const { + // Emit the unwind info structs first. + for (const auto &CFI : Streamer.getWinFrameInfos()) { + MCSection *XData = Streamer.getAssociatedXDataSection(CFI->TextSection); + Streamer.SwitchSection(XData); + ARM64EmitUnwindInfo(Streamer, CFI.get()); + } + + // Now emit RUNTIME_FUNCTION entries. + for (const auto &CFI : Streamer.getWinFrameInfos()) { + MCSection *PData = Streamer.getAssociatedPDataSection(CFI->TextSection); + Streamer.SwitchSection(PData); + ARM64EmitRuntimeFunction(Streamer, CFI.get()); + } +} + +void llvm::Win64EH::ARM64UnwindEmitter::EmitUnwindInfo( + MCStreamer &Streamer, WinEH::FrameInfo *info) const { + // Switch sections (the static function above is meant to be called from + // here and from Emit(). + MCSection *XData = Streamer.getAssociatedXDataSection(info->TextSection); + Streamer.SwitchSection(XData); + ARM64EmitUnwindInfo(Streamer, info); +} |