|  | //===- lib/MC/MCWin64EH.cpp - MCWin64EH implementation --------------------===// | 
|  | // | 
|  | //                     The LLVM Compiler Infrastructure | 
|  | // | 
|  | // This file is distributed under the University of Illinois Open Source | 
|  | // License. See LICENSE.TXT for details. | 
|  | // | 
|  | //===----------------------------------------------------------------------===// | 
|  |  | 
|  | #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); | 
|  | int64_t value; | 
|  | Diff->evaluateAsAbsolute(value, OS->getAssembler()); | 
|  | 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; | 
|  | } | 
|  | } | 
|  |  | 
|  | // 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; | 
|  |  | 
|  | uint32_t FuncLength = 0x0; | 
|  | if (info->FuncletOrFuncEnd) | 
|  | FuncLength = (uint32_t)GetAbsDifference(streamer, info->FuncletOrFuncEnd, | 
|  | info->Begin); | 
|  | FuncLength /= 4; | 
|  | uint32_t PrologCodeBytes = ARM64CountOfUnwindCodes(info->Instructions); | 
|  | uint32_t TotalCodeBytes = PrologCodeBytes; | 
|  |  | 
|  | // Process epilogs. | 
|  | MapVector<MCSymbol *, uint32_t> EpilogInfo; | 
|  | for (auto &I : info->EpilogMap) { | 
|  | MCSymbol *EpilogStart = I.first; | 
|  | auto &EpilogInstrs = I.second; | 
|  | uint32_t CodeBytes = ARM64CountOfUnwindCodes(EpilogInstrs); | 
|  | EpilogInfo[EpilogStart] = TotalCodeBytes; | 
|  | TotalCodeBytes += CodeBytes; | 
|  | } | 
|  |  | 
|  | // 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); | 
|  | } |