//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains support for writing DWARF exception info into asm files. // //===----------------------------------------------------------------------===// #include "DwarfException.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringExtras.h" #include "llvm/ADT/Twine.h" #include "llvm/CodeGen/AsmPrinter.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/Mangler.h" #include "llvm/IR/Module.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCExpr.h" #include "llvm/MC/MCSection.h" #include "llvm/MC/MCStreamer.h" #include "llvm/MC/MCSymbol.h" #include "llvm/Support/Dwarf.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/FormattedStream.h" #include "llvm/Support/LEB128.h" #include "llvm/Target/TargetFrameLowering.h" #include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetOptions.h" #include "llvm/Target/TargetRegisterInfo.h" using namespace llvm; DwarfException::DwarfException(AsmPrinter *A) : Asm(A), MMI(Asm->MMI) {} DwarfException::~DwarfException() {} /// SharedTypeIds - How many leading type ids two landing pads have in common. unsigned DwarfException::SharedTypeIds(const LandingPadInfo *L, const LandingPadInfo *R) { const std::vector &LIds = L->TypeIds, &RIds = R->TypeIds; unsigned LSize = LIds.size(), RSize = RIds.size(); unsigned MinSize = LSize < RSize ? LSize : RSize; unsigned Count = 0; for (; Count != MinSize; ++Count) if (LIds[Count] != RIds[Count]) return Count; return Count; } /// ComputeActionsTable - Compute the actions table and gather the first action /// index for each landing pad site. unsigned DwarfException:: ComputeActionsTable(const SmallVectorImpl &LandingPads, SmallVectorImpl &Actions, SmallVectorImpl &FirstActions) { // The action table follows the call-site table in the LSDA. The individual // records are of two types: // // * Catch clause // * Exception specification // // The two record kinds have the same format, with only small differences. // They are distinguished by the "switch value" field: Catch clauses // (TypeInfos) have strictly positive switch values, and exception // specifications (FilterIds) have strictly negative switch values. Value 0 // indicates a catch-all clause. // // Negative type IDs index into FilterIds. Positive type IDs index into // TypeInfos. The value written for a positive type ID is just the type ID // itself. For a negative type ID, however, the value written is the // (negative) byte offset of the corresponding FilterIds entry. The byte // offset is usually equal to the type ID (because the FilterIds entries are // written using a variable width encoding, which outputs one byte per entry // as long as the value written is not too large) but can differ. This kind // of complication does not occur for positive type IDs because type infos are // output using a fixed width encoding. FilterOffsets[i] holds the byte // offset corresponding to FilterIds[i]. const std::vector &FilterIds = MMI->getFilterIds(); SmallVector FilterOffsets; FilterOffsets.reserve(FilterIds.size()); int Offset = -1; for (std::vector::const_iterator I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) { FilterOffsets.push_back(Offset); Offset -= getULEB128Size(*I); } FirstActions.reserve(LandingPads.size()); int FirstAction = 0; unsigned SizeActions = 0; const LandingPadInfo *PrevLPI = nullptr; for (SmallVectorImpl::const_iterator I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) { const LandingPadInfo *LPI = *I; const std::vector &TypeIds = LPI->TypeIds; unsigned NumShared = PrevLPI ? SharedTypeIds(LPI, PrevLPI) : 0; unsigned SizeSiteActions = 0; if (NumShared < TypeIds.size()) { unsigned SizeAction = 0; unsigned PrevAction = (unsigned)-1; if (NumShared) { unsigned SizePrevIds = PrevLPI->TypeIds.size(); assert(Actions.size()); PrevAction = Actions.size() - 1; SizeAction = getSLEB128Size(Actions[PrevAction].NextAction) + getSLEB128Size(Actions[PrevAction].ValueForTypeID); for (unsigned j = NumShared; j != SizePrevIds; ++j) { assert(PrevAction != (unsigned)-1 && "PrevAction is invalid!"); SizeAction -= getSLEB128Size(Actions[PrevAction].ValueForTypeID); SizeAction += -Actions[PrevAction].NextAction; PrevAction = Actions[PrevAction].Previous; } } // Compute the actions. for (unsigned J = NumShared, M = TypeIds.size(); J != M; ++J) { int TypeID = TypeIds[J]; assert(-1 - TypeID < (int)FilterOffsets.size() && "Unknown filter id!"); int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID; unsigned SizeTypeID = getSLEB128Size(ValueForTypeID); int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0; SizeAction = SizeTypeID + getSLEB128Size(NextAction); SizeSiteActions += SizeAction; ActionEntry Action = { ValueForTypeID, NextAction, PrevAction }; Actions.push_back(Action); PrevAction = Actions.size() - 1; } // Record the first action of the landing pad site. FirstAction = SizeActions + SizeSiteActions - SizeAction + 1; } // else identical - re-use previous FirstAction // Information used when created the call-site table. The action record // field of the call site record is the offset of the first associated // action record, relative to the start of the actions table. This value is // biased by 1 (1 indicating the start of the actions table), and 0 // indicates that there are no actions. FirstActions.push_back(FirstAction); // Compute this sites contribution to size. SizeActions += SizeSiteActions; PrevLPI = LPI; } return SizeActions; } /// CallToNoUnwindFunction - Return `true' if this is a call to a function /// marked `nounwind'. Return `false' otherwise. bool DwarfException::CallToNoUnwindFunction(const MachineInstr *MI) { assert(MI->isCall() && "This should be a call instruction!"); bool MarkedNoUnwind = false; bool SawFunc = false; for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) { const MachineOperand &MO = MI->getOperand(I); if (!MO.isGlobal()) continue; const Function *F = dyn_cast(MO.getGlobal()); if (!F) continue; if (SawFunc) { // Be conservative. If we have more than one function operand for this // call, then we can't make the assumption that it's the callee and // not a parameter to the call. // // FIXME: Determine if there's a way to say that `F' is the callee or // parameter. MarkedNoUnwind = false; break; } MarkedNoUnwind = F->doesNotThrow(); SawFunc = true; } return MarkedNoUnwind; } /// ComputeCallSiteTable - Compute the call-site table. The entry for an invoke /// has a try-range containing the call, a non-zero landing pad, and an /// appropriate action. The entry for an ordinary call has a try-range /// containing the call and zero for the landing pad and the action. Calls /// marked 'nounwind' have no entry and must not be contained in the try-range /// of any entry - they form gaps in the table. Entries must be ordered by /// try-range address. void DwarfException:: ComputeCallSiteTable(SmallVectorImpl &CallSites, const RangeMapType &PadMap, const SmallVectorImpl &LandingPads, const SmallVectorImpl &FirstActions) { // The end label of the previous invoke or nounwind try-range. MCSymbol *LastLabel = nullptr; // Whether there is a potentially throwing instruction (currently this means // an ordinary call) between the end of the previous try-range and now. bool SawPotentiallyThrowing = false; // Whether the last CallSite entry was for an invoke. bool PreviousIsInvoke = false; // Visit all instructions in order of address. for (const auto &MBB : *Asm->MF) { for (const auto &MI : MBB) { if (!MI.isEHLabel()) { if (MI.isCall()) SawPotentiallyThrowing |= !CallToNoUnwindFunction(&MI); continue; } // End of the previous try-range? MCSymbol *BeginLabel = MI.getOperand(0).getMCSymbol(); if (BeginLabel == LastLabel) SawPotentiallyThrowing = false; // Beginning of a new try-range? RangeMapType::const_iterator L = PadMap.find(BeginLabel); if (L == PadMap.end()) // Nope, it was just some random label. continue; const PadRange &P = L->second; const LandingPadInfo *LandingPad = LandingPads[P.PadIndex]; assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] && "Inconsistent landing pad map!"); // For Dwarf exception handling (SjLj handling doesn't use this). If some // instruction between the previous try-range and this one may throw, // create a call-site entry with no landing pad for the region between the // try-ranges. if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) { CallSiteEntry Site = { LastLabel, BeginLabel, nullptr, 0 }; CallSites.push_back(Site); PreviousIsInvoke = false; } LastLabel = LandingPad->EndLabels[P.RangeIndex]; assert(BeginLabel && LastLabel && "Invalid landing pad!"); if (!LandingPad->LandingPadLabel) { // Create a gap. PreviousIsInvoke = false; } else { // This try-range is for an invoke. CallSiteEntry Site = { BeginLabel, LastLabel, LandingPad->LandingPadLabel, FirstActions[P.PadIndex] }; // Try to merge with the previous call-site. SJLJ doesn't do this if (PreviousIsInvoke && Asm->MAI->isExceptionHandlingDwarf()) { CallSiteEntry &Prev = CallSites.back(); if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) { // Extend the range of the previous entry. Prev.EndLabel = Site.EndLabel; continue; } } // Otherwise, create a new call-site. if (Asm->MAI->isExceptionHandlingDwarf()) CallSites.push_back(Site); else { // SjLj EH must maintain the call sites in the order assigned // to them by the SjLjPrepare pass. unsigned SiteNo = MMI->getCallSiteBeginLabel(BeginLabel); if (CallSites.size() < SiteNo) CallSites.resize(SiteNo); CallSites[SiteNo - 1] = Site; } PreviousIsInvoke = true; } } } // If some instruction between the previous try-range and the end of the // function may throw, create a call-site entry with no landing pad for the // region following the try-range. if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) { CallSiteEntry Site = { LastLabel, nullptr, nullptr, 0 }; CallSites.push_back(Site); } } /// EmitExceptionTable - Emit landing pads and actions. /// /// The general organization of the table is complex, but the basic concepts are /// easy. First there is a header which describes the location and organization /// of the three components that follow. /// /// 1. The landing pad site information describes the range of code covered by /// the try. In our case it's an accumulation of the ranges covered by the /// invokes in the try. There is also a reference to the landing pad that /// handles the exception once processed. Finally an index into the actions /// table. /// 2. The action table, in our case, is composed of pairs of type IDs and next /// action offset. Starting with the action index from the landing pad /// site, each type ID is checked for a match to the current exception. If /// it matches then the exception and type id are passed on to the landing /// pad. Otherwise the next action is looked up. This chain is terminated /// with a next action of zero. If no type id is found then the frame is /// unwound and handling continues. /// 3. Type ID table contains references to all the C++ typeinfo for all /// catches in the function. This tables is reverse indexed base 1. void DwarfException::EmitExceptionTable() { const std::vector &TypeInfos = MMI->getTypeInfos(); const std::vector &FilterIds = MMI->getFilterIds(); const std::vector &PadInfos = MMI->getLandingPads(); // Sort the landing pads in order of their type ids. This is used to fold // duplicate actions. SmallVector LandingPads; LandingPads.reserve(PadInfos.size()); for (unsigned i = 0, N = PadInfos.size(); i != N; ++i) LandingPads.push_back(&PadInfos[i]); // Order landing pads lexicographically by type id. std::sort(LandingPads.begin(), LandingPads.end(), [](const LandingPadInfo *L, const LandingPadInfo *R) { return L->TypeIds < R->TypeIds; }); // Compute the actions table and gather the first action index for each // landing pad site. SmallVector Actions; SmallVector FirstActions; unsigned SizeActions=ComputeActionsTable(LandingPads, Actions, FirstActions); // Invokes and nounwind calls have entries in PadMap (due to being bracketed // by try-range labels when lowered). Ordinary calls do not, so appropriate // try-ranges for them need be deduced when using DWARF exception handling. RangeMapType PadMap; for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) { const LandingPadInfo *LandingPad = LandingPads[i]; for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) { MCSymbol *BeginLabel = LandingPad->BeginLabels[j]; assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!"); PadRange P = { i, j }; PadMap[BeginLabel] = P; } } // Compute the call-site table. SmallVector CallSites; ComputeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions); // Final tallies. // Call sites. bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj; bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true; unsigned CallSiteTableLength; if (IsSJLJ) CallSiteTableLength = 0; else { unsigned SiteStartSize = 4; // dwarf::DW_EH_PE_udata4 unsigned SiteLengthSize = 4; // dwarf::DW_EH_PE_udata4 unsigned LandingPadSize = 4; // dwarf::DW_EH_PE_udata4 CallSiteTableLength = CallSites.size() * (SiteStartSize + SiteLengthSize + LandingPadSize); } for (unsigned i = 0, e = CallSites.size(); i < e; ++i) { CallSiteTableLength += getULEB128Size(CallSites[i].Action); if (IsSJLJ) CallSiteTableLength += getULEB128Size(i); } // Type infos. const MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection(); unsigned TTypeEncoding; unsigned TypeFormatSize; if (!HaveTTData) { // For SjLj exceptions, if there is no TypeInfo, then we just explicitly say // that we're omitting that bit. TTypeEncoding = dwarf::DW_EH_PE_omit; // dwarf::DW_EH_PE_absptr TypeFormatSize = Asm->getDataLayout().getPointerSize(); } else { // Okay, we have actual filters or typeinfos to emit. As such, we need to // pick a type encoding for them. We're about to emit a list of pointers to // typeinfo objects at the end of the LSDA. However, unless we're in static // mode, this reference will require a relocation by the dynamic linker. // // Because of this, we have a couple of options: // // 1) If we are in -static mode, we can always use an absolute reference // from the LSDA, because the static linker will resolve it. // // 2) Otherwise, if the LSDA section is writable, we can output the direct // reference to the typeinfo and allow the dynamic linker to relocate // it. Since it is in a writable section, the dynamic linker won't // have a problem. // // 3) Finally, if we're in PIC mode and the LDSA section isn't writable, // we need to use some form of indirection. For example, on Darwin, // we can output a statically-relocatable reference to a dyld stub. The // offset to the stub is constant, but the contents are in a section // that is updated by the dynamic linker. This is easy enough, but we // need to tell the personality function of the unwinder to indirect // through the dyld stub. // // FIXME: When (3) is actually implemented, we'll have to emit the stubs // somewhere. This predicate should be moved to a shared location that is // in target-independent code. // TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding(); TypeFormatSize = Asm->GetSizeOfEncodedValue(TTypeEncoding); } // Begin the exception table. // Sometimes we want not to emit the data into separate section (e.g. ARM // EHABI). In this case LSDASection will be NULL. if (LSDASection) Asm->OutStreamer.SwitchSection(LSDASection); Asm->EmitAlignment(2); // Emit the LSDA. MCSymbol *GCCETSym = Asm->OutContext.GetOrCreateSymbol(Twine("GCC_except_table")+ Twine(Asm->getFunctionNumber())); Asm->OutStreamer.EmitLabel(GCCETSym); Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("exception", Asm->getFunctionNumber())); if (IsSJLJ) Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("_LSDA_", Asm->getFunctionNumber())); // Emit the LSDA header. Asm->EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart"); Asm->EmitEncodingByte(TTypeEncoding, "@TType"); // The type infos need to be aligned. GCC does this by inserting padding just // before the type infos. However, this changes the size of the exception // table, so you need to take this into account when you output the exception // table size. However, the size is output using a variable length encoding. // So by increasing the size by inserting padding, you may increase the number // of bytes used for writing the size. If it increases, say by one byte, then // you now need to output one less byte of padding to get the type infos // aligned. However this decreases the size of the exception table. This // changes the value you have to output for the exception table size. Due to // the variable length encoding, the number of bytes used for writing the // length may decrease. If so, you then have to increase the amount of // padding. And so on. If you look carefully at the GCC code you will see that // it indeed does this in a loop, going on and on until the values stabilize. // We chose another solution: don't output padding inside the table like GCC // does, instead output it before the table. unsigned SizeTypes = TypeInfos.size() * TypeFormatSize; unsigned CallSiteTableLengthSize = getULEB128Size(CallSiteTableLength); unsigned TTypeBaseOffset = sizeof(int8_t) + // Call site format CallSiteTableLengthSize + // Call site table length size CallSiteTableLength + // Call site table length SizeActions + // Actions size SizeTypes; unsigned TTypeBaseOffsetSize = getULEB128Size(TTypeBaseOffset); unsigned TotalSize = sizeof(int8_t) + // LPStart format sizeof(int8_t) + // TType format (HaveTTData ? TTypeBaseOffsetSize : 0) + // TType base offset size TTypeBaseOffset; // TType base offset unsigned SizeAlign = (4 - TotalSize) & 3; if (HaveTTData) { // Account for any extra padding that will be added to the call site table // length. Asm->EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign); SizeAlign = 0; } bool VerboseAsm = Asm->OutStreamer.isVerboseAsm(); // SjLj Exception handling if (IsSJLJ) { Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site"); // Add extra padding if it wasn't added to the TType base offset. Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign); // Emit the landing pad site information. unsigned idx = 0; for (SmallVectorImpl::const_iterator I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) { const CallSiteEntry &S = *I; // Offset of the landing pad, counted in 16-byte bundles relative to the // @LPStart address. if (VerboseAsm) { Asm->OutStreamer.AddComment(">> Call Site " + Twine(idx) + " <<"); Asm->OutStreamer.AddComment(" On exception at call site "+Twine(idx)); } Asm->EmitULEB128(idx); // Offset of the first associated action record, relative to the start of // the action table. This value is biased by 1 (1 indicates the start of // the action table), and 0 indicates that there are no actions. if (VerboseAsm) { if (S.Action == 0) Asm->OutStreamer.AddComment(" Action: cleanup"); else Asm->OutStreamer.AddComment(" Action: " + Twine((S.Action - 1) / 2 + 1)); } Asm->EmitULEB128(S.Action); } } else { // DWARF Exception handling assert(Asm->MAI->isExceptionHandlingDwarf()); // The call-site table is a list of all call sites that may throw an // exception (including C++ 'throw' statements) in the procedure // fragment. It immediately follows the LSDA header. Each entry indicates, // for a given call, the first corresponding action record and corresponding // landing pad. // // The table begins with the number of bytes, stored as an LEB128 // compressed, unsigned integer. The records immediately follow the record // count. They are sorted in increasing call-site address. Each record // indicates: // // * The position of the call-site. // * The position of the landing pad. // * The first action record for that call site. // // A missing entry in the call-site table indicates that a call is not // supposed to throw. // Emit the landing pad call site table. Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site"); // Add extra padding if it wasn't added to the TType base offset. Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign); unsigned Entry = 0; for (SmallVectorImpl::const_iterator I = CallSites.begin(), E = CallSites.end(); I != E; ++I) { const CallSiteEntry &S = *I; MCSymbol *EHFuncBeginSym = Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber()); MCSymbol *BeginLabel = S.BeginLabel; if (!BeginLabel) BeginLabel = EHFuncBeginSym; MCSymbol *EndLabel = S.EndLabel; if (!EndLabel) EndLabel = Asm->GetTempSymbol("eh_func_end", Asm->getFunctionNumber()); // Offset of the call site relative to the previous call site, counted in // number of 16-byte bundles. The first call site is counted relative to // the start of the procedure fragment. if (VerboseAsm) Asm->OutStreamer.AddComment(">> Call Site " + Twine(++Entry) + " <<"); Asm->EmitLabelDifference(BeginLabel, EHFuncBeginSym, 4); if (VerboseAsm) Asm->OutStreamer.AddComment(Twine(" Call between ") + BeginLabel->getName() + " and " + EndLabel->getName()); Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Offset of the landing pad, counted in 16-byte bundles relative to the // @LPStart address. if (!S.PadLabel) { if (VerboseAsm) Asm->OutStreamer.AddComment(" has no landing pad"); Asm->OutStreamer.EmitIntValue(0, 4/*size*/); } else { if (VerboseAsm) Asm->OutStreamer.AddComment(Twine(" jumps to ") + S.PadLabel->getName()); Asm->EmitLabelDifference(S.PadLabel, EHFuncBeginSym, 4); } // Offset of the first associated action record, relative to the start of // the action table. This value is biased by 1 (1 indicates the start of // the action table), and 0 indicates that there are no actions. if (VerboseAsm) { if (S.Action == 0) Asm->OutStreamer.AddComment(" On action: cleanup"); else Asm->OutStreamer.AddComment(" On action: " + Twine((S.Action - 1) / 2 + 1)); } Asm->EmitULEB128(S.Action); } } // Emit the Action Table. int Entry = 0; for (SmallVectorImpl::const_iterator I = Actions.begin(), E = Actions.end(); I != E; ++I) { const ActionEntry &Action = *I; if (VerboseAsm) { // Emit comments that decode the action table. Asm->OutStreamer.AddComment(">> Action Record " + Twine(++Entry) + " <<"); } // Type Filter // // Used by the runtime to match the type of the thrown exception to the // type of the catch clauses or the types in the exception specification. if (VerboseAsm) { if (Action.ValueForTypeID > 0) Asm->OutStreamer.AddComment(" Catch TypeInfo " + Twine(Action.ValueForTypeID)); else if (Action.ValueForTypeID < 0) Asm->OutStreamer.AddComment(" Filter TypeInfo " + Twine(Action.ValueForTypeID)); else Asm->OutStreamer.AddComment(" Cleanup"); } Asm->EmitSLEB128(Action.ValueForTypeID); // Action Record // // Self-relative signed displacement in bytes of the next action record, // or 0 if there is no next action record. if (VerboseAsm) { if (Action.NextAction == 0) { Asm->OutStreamer.AddComment(" No further actions"); } else { unsigned NextAction = Entry + (Action.NextAction + 1) / 2; Asm->OutStreamer.AddComment(" Continue to action "+Twine(NextAction)); } } Asm->EmitSLEB128(Action.NextAction); } EmitTypeInfos(TTypeEncoding); Asm->EmitAlignment(2); } void DwarfException::EmitTypeInfos(unsigned TTypeEncoding) { const std::vector &TypeInfos = MMI->getTypeInfos(); const std::vector &FilterIds = MMI->getFilterIds(); bool VerboseAsm = Asm->OutStreamer.isVerboseAsm(); int Entry = 0; // Emit the Catch TypeInfos. if (VerboseAsm && !TypeInfos.empty()) { Asm->OutStreamer.AddComment(">> Catch TypeInfos <<"); Asm->OutStreamer.AddBlankLine(); Entry = TypeInfos.size(); } for (std::vector::const_reverse_iterator I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) { const GlobalVariable *GV = *I; if (VerboseAsm) Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--)); Asm->EmitTTypeReference(GV, TTypeEncoding); } // Emit the Exception Specifications. if (VerboseAsm && !FilterIds.empty()) { Asm->OutStreamer.AddComment(">> Filter TypeInfos <<"); Asm->OutStreamer.AddBlankLine(); Entry = 0; } for (std::vector::const_iterator I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) { unsigned TypeID = *I; if (VerboseAsm) { --Entry; if (TypeID != 0) Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry)); } Asm->EmitULEB128(TypeID); } } /// endModule - Emit all exception information that should come after the /// content. void DwarfException::endModule() { llvm_unreachable("Should be implemented"); } /// beginFunction - Gather pre-function exception information. Assumes it's /// being emitted immediately after the function entry point. void DwarfException::beginFunction(const MachineFunction *MF) { llvm_unreachable("Should be implemented"); } /// endFunction - Gather and emit post-function exception information. void DwarfException::endFunction(const MachineFunction *) { llvm_unreachable("Should be implemented"); }