+ Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
+
+ // Externally visible entry into the functions eh frame info.
+ // If the corresponding function is static, this should not be
+ // externally visible.
+ if (linkage != Function::InternalLinkage) {
+ if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
+ O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
+ }
+
+ // If corresponding function is weak definition, this should be too.
+ if ((linkage == Function::WeakLinkage ||
+ linkage == Function::LinkOnceLinkage) &&
+ TAI->getWeakDefDirective())
+ O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
+
+ // If there are no calls then you can't unwind. This may mean we can
+ // omit the EH Frame, but some environments do not handle weak absolute
+ // symbols.
+ if (!EHFrameInfo.hasCalls &&
+ ((linkage != Function::WeakLinkage &&
+ linkage != Function::LinkOnceLinkage) ||
+ !TAI->getWeakDefDirective() ||
+ TAI->getSupportsWeakOmittedEHFrame()))
+ {
+ O << EHFrameInfo.FnName << " = 0\n";
+ // This name has no connection to the function, so it might get
+ // dead-stripped when the function is not, erroneously. Prohibit
+ // dead-stripping unconditionally.
+ if (const char *UsedDirective = TAI->getUsedDirective())
+ O << UsedDirective << EHFrameInfo.FnName << "\n\n";
+ } else {
+ O << EHFrameInfo.FnName << ":\n";
+
+ // EH frame header.
+ EmitDifference("eh_frame_end", EHFrameInfo.Number,
+ "eh_frame_begin", EHFrameInfo.Number, true);
+ Asm->EOL("Length of Frame Information Entry");
+
+ EmitLabel("eh_frame_begin", EHFrameInfo.Number);
+
+ EmitSectionOffset("eh_frame_begin", "eh_frame_common",
+ EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
+ true, true);
+ Asm->EOL("FDE CIE offset");
+
+ EmitReference("eh_func_begin", EHFrameInfo.Number, true);
+ Asm->EOL("FDE initial location");
+ EmitDifference("eh_func_end", EHFrameInfo.Number,
+ "eh_func_begin", EHFrameInfo.Number);
+ Asm->EOL("FDE address range");
+
+ // If there is a personality and landing pads then point to the language
+ // specific data area in the exception table.
+ if (EHFrameInfo.PersonalityIndex) {
+ Asm->EmitULEB128Bytes(TAI->getShortenEHDataOn64Bit() ? 8 : 4);
+ Asm->EOL("Augmentation size");
+
+ if (EHFrameInfo.hasLandingPads) {
+ EmitReference("exception", EHFrameInfo.Number, true);
+ } else if (TD->getPointerSize() == 8) {
+ Asm->EmitInt64((int)0);
+ } else {
+ Asm->EmitInt32((int)0);
+ }
+ Asm->EOL("Language Specific Data Area");
+ } else {
+ Asm->EmitULEB128Bytes(0);
+ Asm->EOL("Augmentation size");
+ }
+
+ // Indicate locations of function specific callee saved registers in
+ // frame.
+ EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves, true);
+
+ Asm->EmitAlignment(2);
+ EmitLabel("eh_frame_end", EHFrameInfo.Number);
+
+ // If the function is marked used, this table should be also. We cannot
+ // make the mark unconditional in this case, since retaining the table
+ // also retains the function in this case, and there is code around
+ // that depends on unused functions (calling undefined externals) being
+ // dead-stripped to link correctly. Yes, there really is.
+ if (MMI->getUsedFunctions().count(EHFrameInfo.function))
+ if (const char *UsedDirective = TAI->getUsedDirective())
+ O << UsedDirective << EHFrameInfo.FnName << "\n\n";
+ }
+ }
+
+ /// 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 the 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 reversed indexed base 1.
+
+ /// SharedTypeIds - How many leading type ids two landing pads have in common.
+ static unsigned SharedTypeIds(const LandingPadInfo *L,
+ const LandingPadInfo *R) {
+ const std::vector<int> &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;
+ }
+
+ /// PadLT - Order landing pads lexicographically by type id.
+ static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
+ const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
+ unsigned LSize = LIds.size(), RSize = RIds.size();
+ unsigned MinSize = LSize < RSize ? LSize : RSize;
+
+ for (unsigned i = 0; i != MinSize; ++i)
+ if (LIds[i] != RIds[i])
+ return LIds[i] < RIds[i];
+
+ return LSize < RSize;
+ }
+
+ struct KeyInfo {
+ static inline unsigned getEmptyKey() { return -1U; }
+ static inline unsigned getTombstoneKey() { return -2U; }
+ static unsigned getHashValue(const unsigned &Key) { return Key; }
+ static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
+ static bool isPod() { return true; }
+ };
+
+ /// ActionEntry - Structure describing an entry in the actions table.
+ struct ActionEntry {
+ int ValueForTypeID; // The value to write - may not be equal to the type id.
+ int NextAction;
+ struct ActionEntry *Previous;
+ };
+
+ /// PadRange - Structure holding a try-range and the associated landing pad.
+ struct PadRange {
+ // The index of the landing pad.
+ unsigned PadIndex;
+ // The index of the begin and end labels in the landing pad's label lists.
+ unsigned RangeIndex;
+ };
+
+ typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
+
+ /// CallSiteEntry - Structure describing an entry in the call-site table.
+ struct CallSiteEntry {
+ // The 'try-range' is BeginLabel .. EndLabel.
+ unsigned BeginLabel; // zero indicates the start of the function.
+ unsigned EndLabel; // zero indicates the end of the function.
+ // The landing pad starts at PadLabel.
+ unsigned PadLabel; // zero indicates that there is no landing pad.
+ unsigned Action;
+ };
+
+ void EmitExceptionTable() {
+ // Map all labels and get rid of any dead landing pads.
+ MMI->TidyLandingPads();
+
+ const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
+ const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
+ const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
+ if (PadInfos.empty()) return;
+
+ // Sort the landing pads in order of their type ids. This is used to fold
+ // duplicate actions.
+ SmallVector<const LandingPadInfo *, 64> LandingPads;
+ LandingPads.reserve(PadInfos.size());
+ for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
+ LandingPads.push_back(&PadInfos[i]);
+ std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
+
+ // 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].
+ SmallVector<int, 16> FilterOffsets;
+ FilterOffsets.reserve(FilterIds.size());
+ int Offset = -1;
+ for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
+ E = FilterIds.end(); I != E; ++I) {
+ FilterOffsets.push_back(Offset);
+ Offset -= Asm->SizeULEB128(*I);
+ }
+
+ // Compute the actions table and gather the first action index for each
+ // landing pad site.
+ SmallVector<ActionEntry, 32> Actions;
+ SmallVector<unsigned, 64> FirstActions;
+ FirstActions.reserve(LandingPads.size());
+
+ int FirstAction = 0;
+ unsigned SizeActions = 0;
+ for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
+ const LandingPadInfo *LP = LandingPads[i];
+ const std::vector<int> &TypeIds = LP->TypeIds;
+ const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
+ unsigned SizeSiteActions = 0;
+
+ if (NumShared < TypeIds.size()) {
+ unsigned SizeAction = 0;
+ ActionEntry *PrevAction = 0;
+
+ if (NumShared) {
+ const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
+ assert(Actions.size());
+ PrevAction = &Actions.back();
+ SizeAction = Asm->SizeSLEB128(PrevAction->NextAction) +
+ Asm->SizeSLEB128(PrevAction->ValueForTypeID);
+ for (unsigned j = NumShared; j != SizePrevIds; ++j) {
+ SizeAction -= Asm->SizeSLEB128(PrevAction->ValueForTypeID);
+ SizeAction += -PrevAction->NextAction;
+ PrevAction = PrevAction->Previous;
+ }
+ }
+
+ // Compute the actions.
+ for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
+ int TypeID = TypeIds[I];
+ assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
+ int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
+ unsigned SizeTypeID = Asm->SizeSLEB128(ValueForTypeID);
+
+ int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
+ SizeAction = SizeTypeID + Asm->SizeSLEB128(NextAction);
+ SizeSiteActions += SizeAction;
+
+ ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
+ Actions.push_back(Action);
+
+ PrevAction = &Actions.back();
+ }
+
+ // Record the first action of the landing pad site.
+ FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
+ } // else identical - re-use previous FirstAction
+
+ FirstActions.push_back(FirstAction);
+
+ // Compute this sites contribution to size.
+ SizeActions += SizeSiteActions;
+ }
+
+ // 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.
+ SmallVector<CallSiteEntry, 64> CallSites;
+
+ RangeMapType PadMap;
+ // 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.
+ 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) {
+ unsigned BeginLabel = LandingPad->BeginLabels[j];
+ assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
+ PadRange P = { i, j };
+ PadMap[BeginLabel] = P;
+ }
+ }
+
+ // The end label of the previous invoke or nounwind try-range.
+ unsigned LastLabel = 0;
+
+ // 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 (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
+ I != E; ++I) {
+ for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
+ MI != E; ++MI) {
+ if (MI->getOpcode() != TargetInstrInfo::LABEL) {
+ SawPotentiallyThrowing |= MI->getDesc().isCall();
+ continue;
+ }
+
+ unsigned BeginLabel = MI->getOperand(0).getImm();
+ assert(BeginLabel && "Invalid label!");
+
+ // End of the previous try-range?
+ if (BeginLabel == LastLabel)
+ SawPotentiallyThrowing = false;
+
+ // Beginning of a new try-range?
+ RangeMapType::iterator L = PadMap.find(BeginLabel);
+ if (L == PadMap.end())
+ // Nope, it was just some random label.
+ continue;
+
+ PadRange P = L->second;
+ const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
+
+ assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
+ "Inconsistent landing pad map!");
+
+ // 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) {
+ CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
+ CallSites.push_back(Site);
+ PreviousIsInvoke = false;
+ }
+
+ LastLabel = LandingPad->EndLabels[P.RangeIndex];
+ assert(BeginLabel && LastLabel && "Invalid landing pad!");
+
+ if (LandingPad->LandingPadLabel) {
+ // This try-range is for an invoke.
+ CallSiteEntry Site = {BeginLabel, LastLabel,
+ LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
+
+ // Try to merge with the previous call-site.
+ if (PreviousIsInvoke) {
+ CallSiteEntry &Prev = CallSites[CallSites.size()-1];
+ 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.
+ CallSites.push_back(Site);
+ PreviousIsInvoke = true;
+ } else {
+ // Create a gap.
+ PreviousIsInvoke = false;
+ }
+ }
+ }
+ // 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) {
+ CallSiteEntry Site = {LastLabel, 0, 0, 0};
+ CallSites.push_back(Site);
+ }
+
+ // Final tallies.
+ unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
+ sizeof(int32_t) + // Site length.
+ sizeof(int32_t)); // Landing pad.
+ for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
+ SizeSites += Asm->SizeULEB128(CallSites[i].Action);
+
+ unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
+
+ unsigned TypeOffset = sizeof(int8_t) + // Call site format
+ Asm->SizeULEB128(SizeSites) + // Call-site table length
+ SizeSites + SizeActions + SizeTypes;
+
+ unsigned TotalSize = sizeof(int8_t) + // LPStart format
+ sizeof(int8_t) + // TType format
+ Asm->SizeULEB128(TypeOffset) + // TType base offset
+ TypeOffset;
+
+ unsigned SizeAlign = (4 - TotalSize) & 3;
+
+ // Begin the exception table.
+ Asm->SwitchToDataSection(TAI->getDwarfExceptionSection());
+ O << "GCC_except_table" << SubprogramCount << ":\n";
+ Asm->EmitAlignment(2);
+ for (unsigned i = 0; i != SizeAlign; ++i) {
+ Asm->EmitInt8(0);
+ Asm->EOL("Padding");
+ }
+ EmitLabel("exception", SubprogramCount);
+
+ // Emit the header.
+ Asm->EmitInt8(DW_EH_PE_omit);
+ Asm->EOL("LPStart format (DW_EH_PE_omit)");
+ Asm->EmitInt8(DW_EH_PE_absptr);
+ Asm->EOL("TType format (DW_EH_PE_absptr)");
+ Asm->EmitULEB128Bytes(TypeOffset);
+ Asm->EOL("TType base offset");
+ Asm->EmitInt8(DW_EH_PE_udata4);
+ Asm->EOL("Call site format (DW_EH_PE_udata4)");
+ Asm->EmitULEB128Bytes(SizeSites);
+ Asm->EOL("Call-site table length");
+
+ // Emit the landing pad site information.
+ for (unsigned i = 0; i < CallSites.size(); ++i) {
+ CallSiteEntry &S = CallSites[i];
+ const char *BeginTag;
+ unsigned BeginNumber;
+
+ if (!S.BeginLabel) {
+ BeginTag = "eh_func_begin";
+ BeginNumber = SubprogramCount;
+ } else {
+ BeginTag = "label";
+ BeginNumber = S.BeginLabel;
+ }
+
+ EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
+ TAI->getShortenEHDataOn64Bit(), true);
+ Asm->EOL("Region start");
+
+ if (!S.EndLabel) {
+ EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
+ TAI->getShortenEHDataOn64Bit());
+ } else {
+ EmitDifference("label", S.EndLabel, BeginTag, BeginNumber,
+ TAI->getShortenEHDataOn64Bit());
+ }
+ Asm->EOL("Region length");
+
+ if (!S.PadLabel) {
+ if (TD->getPointerSize() == sizeof(int32_t) || TAI->getShortenEHDataOn64Bit())
+ Asm->EmitInt32(0);
+ else
+ Asm->EmitInt64(0);
+ } else {
+ EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
+ TAI->getShortenEHDataOn64Bit(), true);
+ }
+ Asm->EOL("Landing pad");
+
+ Asm->EmitULEB128Bytes(S.Action);
+ Asm->EOL("Action");
+ }
+
+ // Emit the actions.
+ for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
+ ActionEntry &Action = Actions[I];
+
+ Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
+ Asm->EOL("TypeInfo index");
+ Asm->EmitSLEB128Bytes(Action.NextAction);
+ Asm->EOL("Next action");
+ }
+
+ // Emit the type ids.
+ for (unsigned M = TypeInfos.size(); M; --M) {
+ GlobalVariable *GV = TypeInfos[M - 1];
+
+ PrintRelDirective();
+
+ if (GV)
+ O << Asm->getGlobalLinkName(GV);
+ else
+ O << "0";
+
+ Asm->EOL("TypeInfo");
+ }
+
+ // Emit the filter typeids.
+ for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
+ unsigned TypeID = FilterIds[j];
+ Asm->EmitULEB128Bytes(TypeID);
+ Asm->EOL("Filter TypeInfo index");
+ }
+
+ Asm->EmitAlignment(2);
+ }
+
+public:
+ //===--------------------------------------------------------------------===//
+ // Main entry points.
+ //
+ DwarfException(std::ostream &OS, AsmPrinter *A, const TargetAsmInfo *T)
+ : Dwarf(OS, A, T, "eh")
+ , shouldEmit(false)
+ {}
+
+ virtual ~DwarfException() {}
+
+ /// SetModuleInfo - Set machine module information when it's known that pass
+ /// manager has created it. Set by the target AsmPrinter.
+ void SetModuleInfo(MachineModuleInfo *mmi) {
+ MMI = mmi;
+ }
+
+ /// BeginModule - Emit all exception information that should come prior to the
+ /// content.
+ void BeginModule(Module *M) {
+ this->M = M;
+ }
+
+ /// EndModule - Emit all exception information that should come after the
+ /// content.
+ void EndModule() {
+ if (!shouldEmit) return;
+
+ const std::vector<Function *> Personalities = MMI->getPersonalities();
+ for (unsigned i =0; i < Personalities.size(); ++i)
+ EmitCommonEHFrame(Personalities[i], i);
+
+ for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
+ E = EHFrames.end(); I != E; ++I)
+ EmitEHFrame(*I);
+ }
+
+ /// BeginFunction - Gather pre-function exception information. Assumes being
+ /// emitted immediately after the function entry point.
+ void BeginFunction(MachineFunction *MF) {
+ this->MF = MF;
+
+ if (MMI &&
+ ExceptionHandling &&
+ TAI->doesSupportExceptionHandling()) {
+ shouldEmit = true;
+ // Assumes in correct section after the entry point.
+ EmitLabel("eh_func_begin", ++SubprogramCount);
+ }
+ }
+
+ /// EndFunction - Gather and emit post-function exception information.
+ ///
+ void EndFunction() {
+ if (!shouldEmit) return;
+
+ EmitLabel("eh_func_end", SubprogramCount);
+ EmitExceptionTable();
+
+ // Save EH frame information
+ EHFrames.
+ push_back(FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
+ SubprogramCount,
+ MMI->getPersonalityIndex(),
+ MF->getFrameInfo()->hasCalls(),
+ !MMI->getLandingPads().empty(),
+ MMI->getFrameMoves(),
+ MF->getFunction()));