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Diffstat (limited to 'contrib/llvm/lib/CodeGen/AsmPrinter/WinException.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/AsmPrinter/WinException.cpp | 654 |
1 files changed, 654 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/WinException.cpp new file mode 100644 index 0000000..79830bc --- /dev/null +++ b/contrib/llvm/lib/CodeGen/AsmPrinter/WinException.cpp @@ -0,0 +1,654 @@ +//===-- CodeGen/AsmPrinter/WinException.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 Win64 exception info into asm files. +// +//===----------------------------------------------------------------------===// + +#include "WinException.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/CodeGen/WinEHFuncInfo.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/MC/MCWin64EH.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/FormattedStream.h" +#include "llvm/Target/TargetFrameLowering.h" +#include "llvm/Target/TargetLoweringObjectFile.h" +#include "llvm/Target/TargetOptions.h" +#include "llvm/Target/TargetRegisterInfo.h" +using namespace llvm; + +WinException::WinException(AsmPrinter *A) : EHStreamer(A) { + // MSVC's EH tables are always composed of 32-bit words. All known 64-bit + // platforms use an imagerel32 relocation to refer to symbols. + useImageRel32 = (A->getDataLayout().getPointerSizeInBits() == 64); +} + +WinException::~WinException() {} + +/// endModule - Emit all exception information that should come after the +/// content. +void WinException::endModule() { + auto &OS = *Asm->OutStreamer; + const Module *M = MMI->getModule(); + for (const Function &F : *M) + if (F.hasFnAttribute("safeseh")) + OS.EmitCOFFSafeSEH(Asm->getSymbol(&F)); +} + +void WinException::beginFunction(const MachineFunction *MF) { + shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false; + + // If any landing pads survive, we need an EH table. + bool hasLandingPads = !MMI->getLandingPads().empty(); + + const Function *F = MF->getFunction(); + const Function *ParentF = MMI->getWinEHParent(F); + + shouldEmitMoves = Asm->needsSEHMoves(); + + const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); + unsigned PerEncoding = TLOF.getPersonalityEncoding(); + const Function *Per = MMI->getPersonality(); + + shouldEmitPersonality = hasLandingPads && + PerEncoding != dwarf::DW_EH_PE_omit && Per; + + unsigned LSDAEncoding = TLOF.getLSDAEncoding(); + shouldEmitLSDA = shouldEmitPersonality && + LSDAEncoding != dwarf::DW_EH_PE_omit; + + // If we're not using CFI, we don't want the CFI or the personality. Emit the + // LSDA if this is the parent function. + if (!Asm->MAI->usesWindowsCFI()) { + shouldEmitLSDA = (hasLandingPads && F == ParentF); + shouldEmitPersonality = false; + return; + } + + // If this was an outlined handler, we need to define the label corresponding + // to the offset of the parent frame relative to the stack pointer after the + // prologue. + if (F != ParentF) { + WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF); + auto I = FuncInfo.CatchHandlerParentFrameObjOffset.find(F); + if (I != FuncInfo.CatchHandlerParentFrameObjOffset.end()) { + MCSymbol *HandlerTypeParentFrameOffset = + Asm->OutContext.getOrCreateParentFrameOffsetSymbol( + GlobalValue::getRealLinkageName(F->getName())); + + // Emit a symbol assignment. + Asm->OutStreamer->EmitAssignment( + HandlerTypeParentFrameOffset, + MCConstantExpr::create(I->second, Asm->OutContext)); + } + } + + if (shouldEmitMoves || shouldEmitPersonality) + Asm->OutStreamer->EmitWinCFIStartProc(Asm->CurrentFnSym); + + if (shouldEmitPersonality) { + const MCSymbol *PersHandlerSym = + TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI); + Asm->OutStreamer->EmitWinEHHandler(PersHandlerSym, true, true); + } +} + +/// endFunction - Gather and emit post-function exception information. +/// +void WinException::endFunction(const MachineFunction *MF) { + if (!shouldEmitPersonality && !shouldEmitMoves && !shouldEmitLSDA) + return; + + EHPersonality Per = MMI->getPersonalityType(); + + // Get rid of any dead landing pads if we're not using a Windows EH scheme. In + // Windows EH schemes, the landing pad is not actually reachable. It only + // exists so that we can emit the right table data. + if (!isMSVCEHPersonality(Per)) + MMI->TidyLandingPads(); + + if (shouldEmitPersonality || shouldEmitLSDA) { + Asm->OutStreamer->PushSection(); + + if (shouldEmitMoves || shouldEmitPersonality) { + // Emit an UNWIND_INFO struct describing the prologue. + Asm->OutStreamer->EmitWinEHHandlerData(); + } else { + // Just switch sections to the right xdata section. This use of + // CurrentFnSym assumes that we only emit the LSDA when ending the parent + // function. + MCSection *XData = WinEH::UnwindEmitter::getXDataSection( + Asm->CurrentFnSym, Asm->OutContext); + Asm->OutStreamer->SwitchSection(XData); + } + + // Emit the tables appropriate to the personality function in use. If we + // don't recognize the personality, assume it uses an Itanium-style LSDA. + if (Per == EHPersonality::MSVC_Win64SEH) + emitCSpecificHandlerTable(); + else if (Per == EHPersonality::MSVC_X86SEH) + emitExceptHandlerTable(MF); + else if (Per == EHPersonality::MSVC_CXX) + emitCXXFrameHandler3Table(MF); + else + emitExceptionTable(); + + Asm->OutStreamer->PopSection(); + } + + if (shouldEmitMoves) + Asm->OutStreamer->EmitWinCFIEndProc(); +} + +const MCExpr *WinException::create32bitRef(const MCSymbol *Value) { + if (!Value) + return MCConstantExpr::create(0, Asm->OutContext); + return MCSymbolRefExpr::create(Value, useImageRel32 + ? MCSymbolRefExpr::VK_COFF_IMGREL32 + : MCSymbolRefExpr::VK_None, + Asm->OutContext); +} + +const MCExpr *WinException::create32bitRef(const GlobalValue *GV) { + if (!GV) + return MCConstantExpr::create(0, Asm->OutContext); + return create32bitRef(Asm->getSymbol(GV)); +} + +/// Emit the language-specific data that __C_specific_handler expects. This +/// handler lives in the x64 Microsoft C runtime and allows catching or cleaning +/// up after faults with __try, __except, and __finally. The typeinfo values +/// are not really RTTI data, but pointers to filter functions that return an +/// integer (1, 0, or -1) indicating how to handle the exception. For __finally +/// blocks and other cleanups, the landing pad label is zero, and the filter +/// function is actually a cleanup handler with the same prototype. A catch-all +/// entry is modeled with a null filter function field and a non-zero landing +/// pad label. +/// +/// Possible filter function return values: +/// EXCEPTION_EXECUTE_HANDLER (1): +/// Jump to the landing pad label after cleanups. +/// EXCEPTION_CONTINUE_SEARCH (0): +/// Continue searching this table or continue unwinding. +/// EXCEPTION_CONTINUE_EXECUTION (-1): +/// Resume execution at the trapping PC. +/// +/// Inferred table structure: +/// struct Table { +/// int NumEntries; +/// struct Entry { +/// imagerel32 LabelStart; +/// imagerel32 LabelEnd; +/// imagerel32 FilterOrFinally; // One means catch-all. +/// imagerel32 LabelLPad; // Zero means __finally. +/// } Entries[NumEntries]; +/// }; +void WinException::emitCSpecificHandlerTable() { + const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads(); + + // Simplifying assumptions for first implementation: + // - Cleanups are not implemented. + // - Filters are not implemented. + + // The Itanium LSDA table sorts similar landing pads together to simplify the + // actions table, but we don't need that. + SmallVector<const LandingPadInfo *, 64> LandingPads; + LandingPads.reserve(PadInfos.size()); + for (const auto &LP : PadInfos) + LandingPads.push_back(&LP); + + // Compute label ranges for call sites as we would for the Itanium LSDA, but + // use an all zero action table because we aren't using these actions. + SmallVector<unsigned, 64> FirstActions; + FirstActions.resize(LandingPads.size()); + SmallVector<CallSiteEntry, 64> CallSites; + computeCallSiteTable(CallSites, LandingPads, FirstActions); + + MCSymbol *EHFuncBeginSym = Asm->getFunctionBegin(); + MCSymbol *EHFuncEndSym = Asm->getFunctionEnd(); + + // Emit the number of table entries. + unsigned NumEntries = 0; + for (const CallSiteEntry &CSE : CallSites) { + if (!CSE.LPad) + continue; // Ignore gaps. + NumEntries += CSE.LPad->SEHHandlers.size(); + } + Asm->OutStreamer->EmitIntValue(NumEntries, 4); + + // If there are no actions, we don't need to iterate again. + if (NumEntries == 0) + return; + + // Emit the four-label records for each call site entry. The table has to be + // sorted in layout order, and the call sites should already be sorted. + for (const CallSiteEntry &CSE : CallSites) { + // Ignore gaps. Unlike the Itanium model, unwinding through a frame without + // an EH table entry will propagate the exception rather than terminating + // the program. + if (!CSE.LPad) + continue; + const LandingPadInfo *LPad = CSE.LPad; + + // Compute the label range. We may reuse the function begin and end labels + // rather than forming new ones. + const MCExpr *Begin = + create32bitRef(CSE.BeginLabel ? CSE.BeginLabel : EHFuncBeginSym); + const MCExpr *End; + if (CSE.EndLabel) { + // The interval is half-open, so we have to add one to include the return + // address of the last invoke in the range. + End = MCBinaryExpr::createAdd(create32bitRef(CSE.EndLabel), + MCConstantExpr::create(1, Asm->OutContext), + Asm->OutContext); + } else { + End = create32bitRef(EHFuncEndSym); + } + + // Emit an entry for each action. + for (SEHHandler Handler : LPad->SEHHandlers) { + Asm->OutStreamer->EmitValue(Begin, 4); + Asm->OutStreamer->EmitValue(End, 4); + + // Emit the filter or finally function pointer, if present. Otherwise, + // emit '1' to indicate a catch-all. + const Function *F = Handler.FilterOrFinally; + if (F) + Asm->OutStreamer->EmitValue(create32bitRef(Asm->getSymbol(F)), 4); + else + Asm->OutStreamer->EmitIntValue(1, 4); + + // Emit the recovery address, if present. Otherwise, this must be a + // finally. + const BlockAddress *BA = Handler.RecoverBA; + if (BA) + Asm->OutStreamer->EmitValue( + create32bitRef(Asm->GetBlockAddressSymbol(BA)), 4); + else + Asm->OutStreamer->EmitIntValue(0, 4); + } + } +} + +void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) { + const Function *F = MF->getFunction(); + const Function *ParentF = MMI->getWinEHParent(F); + auto &OS = *Asm->OutStreamer; + WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF); + + StringRef ParentLinkageName = + GlobalValue::getRealLinkageName(ParentF->getName()); + + MCSymbol *FuncInfoXData = nullptr; + if (shouldEmitPersonality) { + FuncInfoXData = Asm->OutContext.getOrCreateSymbol( + Twine("$cppxdata$", ParentLinkageName)); + OS.EmitValue(create32bitRef(FuncInfoXData), 4); + + extendIP2StateTable(MF, ParentF, FuncInfo); + + // Defer emission until we've visited the parent function and all the catch + // handlers. Cleanups don't contribute to the ip2state table, so don't count + // them. + if (ParentF != F && !FuncInfo.CatchHandlerMaxState.count(F)) + return; + ++FuncInfo.NumIPToStateFuncsVisited; + if (FuncInfo.NumIPToStateFuncsVisited != FuncInfo.CatchHandlerMaxState.size()) + return; + } else { + FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(ParentLinkageName); + emitEHRegistrationOffsetLabel(FuncInfo, ParentLinkageName); + } + + MCSymbol *UnwindMapXData = nullptr; + MCSymbol *TryBlockMapXData = nullptr; + MCSymbol *IPToStateXData = nullptr; + if (!FuncInfo.UnwindMap.empty()) + UnwindMapXData = Asm->OutContext.getOrCreateSymbol( + Twine("$stateUnwindMap$", ParentLinkageName)); + if (!FuncInfo.TryBlockMap.empty()) + TryBlockMapXData = Asm->OutContext.getOrCreateSymbol( + Twine("$tryMap$", ParentLinkageName)); + if (!FuncInfo.IPToStateList.empty()) + IPToStateXData = Asm->OutContext.getOrCreateSymbol( + Twine("$ip2state$", ParentLinkageName)); + + // FuncInfo { + // uint32_t MagicNumber + // int32_t MaxState; + // UnwindMapEntry *UnwindMap; + // uint32_t NumTryBlocks; + // TryBlockMapEntry *TryBlockMap; + // uint32_t IPMapEntries; // always 0 for x86 + // IPToStateMapEntry *IPToStateMap; // always 0 for x86 + // uint32_t UnwindHelp; // non-x86 only + // ESTypeList *ESTypeList; + // int32_t EHFlags; + // } + // EHFlags & 1 -> Synchronous exceptions only, no async exceptions. + // EHFlags & 2 -> ??? + // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue. + OS.EmitLabel(FuncInfoXData); + OS.EmitIntValue(0x19930522, 4); // MagicNumber + OS.EmitIntValue(FuncInfo.UnwindMap.size(), 4); // MaxState + OS.EmitValue(create32bitRef(UnwindMapXData), 4); // UnwindMap + OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4); // NumTryBlocks + OS.EmitValue(create32bitRef(TryBlockMapXData), 4); // TryBlockMap + OS.EmitIntValue(FuncInfo.IPToStateList.size(), 4); // IPMapEntries + OS.EmitValue(create32bitRef(IPToStateXData), 4); // IPToStateMap + if (Asm->MAI->usesWindowsCFI()) + OS.EmitIntValue(FuncInfo.UnwindHelpFrameOffset, 4); // UnwindHelp + OS.EmitIntValue(0, 4); // ESTypeList + OS.EmitIntValue(1, 4); // EHFlags + + // UnwindMapEntry { + // int32_t ToState; + // void (*Action)(); + // }; + if (UnwindMapXData) { + OS.EmitLabel(UnwindMapXData); + for (const WinEHUnwindMapEntry &UME : FuncInfo.UnwindMap) { + OS.EmitIntValue(UME.ToState, 4); // ToState + OS.EmitValue(create32bitRef(UME.Cleanup), 4); // Action + } + } + + // TryBlockMap { + // int32_t TryLow; + // int32_t TryHigh; + // int32_t CatchHigh; + // int32_t NumCatches; + // HandlerType *HandlerArray; + // }; + if (TryBlockMapXData) { + OS.EmitLabel(TryBlockMapXData); + SmallVector<MCSymbol *, 1> HandlerMaps; + for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) { + WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I]; + MCSymbol *HandlerMapXData = nullptr; + + if (!TBME.HandlerArray.empty()) + HandlerMapXData = + Asm->OutContext.getOrCreateSymbol(Twine("$handlerMap$") + .concat(Twine(I)) + .concat("$") + .concat(ParentLinkageName)); + + HandlerMaps.push_back(HandlerMapXData); + + int CatchHigh = -1; + for (WinEHHandlerType &HT : TBME.HandlerArray) + CatchHigh = + std::max(CatchHigh, FuncInfo.CatchHandlerMaxState[HT.Handler]); + + assert(TBME.TryLow <= TBME.TryHigh); + OS.EmitIntValue(TBME.TryLow, 4); // TryLow + OS.EmitIntValue(TBME.TryHigh, 4); // TryHigh + OS.EmitIntValue(CatchHigh, 4); // CatchHigh + OS.EmitIntValue(TBME.HandlerArray.size(), 4); // NumCatches + OS.EmitValue(create32bitRef(HandlerMapXData), 4); // HandlerArray + } + + for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) { + WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I]; + MCSymbol *HandlerMapXData = HandlerMaps[I]; + if (!HandlerMapXData) + continue; + // HandlerType { + // int32_t Adjectives; + // TypeDescriptor *Type; + // int32_t CatchObjOffset; + // void (*Handler)(); + // int32_t ParentFrameOffset; // x64 only + // }; + OS.EmitLabel(HandlerMapXData); + for (const WinEHHandlerType &HT : TBME.HandlerArray) { + // Get the frame escape label with the offset of the catch object. If + // the index is -1, then there is no catch object, and we should emit an + // offset of zero, indicating that no copy will occur. + const MCExpr *FrameAllocOffsetRef = nullptr; + if (HT.CatchObjRecoverIdx >= 0) { + MCSymbol *FrameAllocOffset = + Asm->OutContext.getOrCreateFrameAllocSymbol( + GlobalValue::getRealLinkageName(ParentF->getName()), + HT.CatchObjRecoverIdx); + FrameAllocOffsetRef = MCSymbolRefExpr::create( + FrameAllocOffset, MCSymbolRefExpr::VK_None, Asm->OutContext); + } else { + FrameAllocOffsetRef = MCConstantExpr::create(0, Asm->OutContext); + } + + OS.EmitIntValue(HT.Adjectives, 4); // Adjectives + OS.EmitValue(create32bitRef(HT.TypeDescriptor), 4); // Type + OS.EmitValue(FrameAllocOffsetRef, 4); // CatchObjOffset + OS.EmitValue(create32bitRef(HT.Handler), 4); // Handler + + if (shouldEmitPersonality) { + MCSymbol *ParentFrameOffset = + Asm->OutContext.getOrCreateParentFrameOffsetSymbol( + GlobalValue::getRealLinkageName(HT.Handler->getName())); + const MCSymbolRefExpr *ParentFrameOffsetRef = MCSymbolRefExpr::create( + ParentFrameOffset, Asm->OutContext); + OS.EmitValue(ParentFrameOffsetRef, 4); // ParentFrameOffset + } + } + } + } + + // IPToStateMapEntry { + // void *IP; + // int32_t State; + // }; + if (IPToStateXData) { + OS.EmitLabel(IPToStateXData); + for (auto &IPStatePair : FuncInfo.IPToStateList) { + OS.EmitValue(create32bitRef(IPStatePair.first), 4); // IP + OS.EmitIntValue(IPStatePair.second, 4); // State + } + } +} + +void WinException::extendIP2StateTable(const MachineFunction *MF, + const Function *ParentF, + WinEHFuncInfo &FuncInfo) { + const Function *F = MF->getFunction(); + + // The Itanium LSDA table sorts similar landing pads together to simplify the + // actions table, but we don't need that. + SmallVector<const LandingPadInfo *, 64> LandingPads; + const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads(); + LandingPads.reserve(PadInfos.size()); + for (const auto &LP : PadInfos) + LandingPads.push_back(&LP); + + RangeMapType PadMap; + computePadMap(LandingPads, PadMap); + + // The end label of the previous invoke or nounwind try-range. + MCSymbol *LastLabel = Asm->getFunctionBegin(); + + // 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; + + int LastEHState = -2; + + // The parent function and the catch handlers contribute to the 'ip2state' + // table. + + // Include ip2state entries for the beginning of the main function and + // for catch handler functions. + if (F == ParentF) { + FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1)); + LastEHState = -1; + } else if (FuncInfo.HandlerBaseState.count(F)) { + FuncInfo.IPToStateList.push_back( + std::make_pair(LastLabel, FuncInfo.HandlerBaseState[F])); + LastEHState = FuncInfo.HandlerBaseState[F]; + } + for (const auto &MBB : *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!"); + + // FIXME: Should this be using FuncInfo.HandlerBaseState? + if (SawPotentiallyThrowing && LastEHState != -1) { + FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1)); + SawPotentiallyThrowing = false; + LastEHState = -1; + } + + if (LandingPad->WinEHState != LastEHState) + FuncInfo.IPToStateList.push_back( + std::make_pair(BeginLabel, LandingPad->WinEHState)); + LastEHState = LandingPad->WinEHState; + LastLabel = LandingPad->EndLabels[P.RangeIndex]; + } + } +} + +void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo, + StringRef FLinkageName) { + // Outlined helpers called by the EH runtime need to know the offset of the EH + // registration in order to recover the parent frame pointer. Now that we know + // we've code generated the parent, we can emit the label assignment that + // those helpers use to get the offset of the registration node. + assert(FuncInfo.EHRegNodeEscapeIndex != INT_MAX && + "no EH reg node frameescape index"); + MCSymbol *ParentFrameOffset = + Asm->OutContext.getOrCreateParentFrameOffsetSymbol(FLinkageName); + MCSymbol *RegistrationOffsetSym = Asm->OutContext.getOrCreateFrameAllocSymbol( + FLinkageName, FuncInfo.EHRegNodeEscapeIndex); + const MCExpr *RegistrationOffsetSymRef = + MCSymbolRefExpr::create(RegistrationOffsetSym, Asm->OutContext); + Asm->OutStreamer->EmitAssignment(ParentFrameOffset, RegistrationOffsetSymRef); +} + +/// Emit the language-specific data that _except_handler3 and 4 expect. This is +/// functionally equivalent to the __C_specific_handler table, except it is +/// indexed by state number instead of IP. +void WinException::emitExceptHandlerTable(const MachineFunction *MF) { + MCStreamer &OS = *Asm->OutStreamer; + const Function *F = MF->getFunction(); + StringRef FLinkageName = GlobalValue::getRealLinkageName(F->getName()); + + WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(F); + emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName); + + // Emit the __ehtable label that we use for llvm.x86.seh.lsda. + MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName); + OS.EmitLabel(LSDALabel); + + const Function *Per = MMI->getPersonality(); + StringRef PerName = Per->getName(); + int BaseState = -1; + if (PerName == "_except_handler4") { + // The LSDA for _except_handler4 starts with this struct, followed by the + // scope table: + // + // struct EH4ScopeTable { + // int32_t GSCookieOffset; + // int32_t GSCookieXOROffset; + // int32_t EHCookieOffset; + // int32_t EHCookieXOROffset; + // ScopeTableEntry ScopeRecord[]; + // }; + // + // Only the EHCookieOffset field appears to vary, and it appears to be the + // offset from the final saved SP value to the retaddr. + OS.EmitIntValue(-2, 4); + OS.EmitIntValue(0, 4); + // FIXME: Calculate. + OS.EmitIntValue(9999, 4); + OS.EmitIntValue(0, 4); + BaseState = -2; + } + + // Build a list of pointers to LandingPadInfos and then sort by WinEHState. + const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads(); + SmallVector<const LandingPadInfo *, 4> LPads; + LPads.reserve((PadInfos.size())); + for (const LandingPadInfo &LPInfo : PadInfos) + LPads.push_back(&LPInfo); + std::sort(LPads.begin(), LPads.end(), + [](const LandingPadInfo *L, const LandingPadInfo *R) { + return L->WinEHState < R->WinEHState; + }); + + // For each action in each lpad, emit one of these: + // struct ScopeTableEntry { + // int32_t EnclosingLevel; + // int32_t (__cdecl *Filter)(); + // void *HandlerOrFinally; + // }; + // + // The "outermost" action will use BaseState as its enclosing level. Each + // other action will refer to the previous state as its enclosing level. + int CurState = 0; + for (const LandingPadInfo *LPInfo : LPads) { + int EnclosingLevel = BaseState; + assert(CurState + int(LPInfo->SEHHandlers.size()) - 1 == + LPInfo->WinEHState && + "gaps in the SEH scope table"); + for (auto I = LPInfo->SEHHandlers.rbegin(), E = LPInfo->SEHHandlers.rend(); + I != E; ++I) { + const SEHHandler &Handler = *I; + const BlockAddress *BA = Handler.RecoverBA; + const Function *F = Handler.FilterOrFinally; + assert(F && "cannot catch all in 32-bit SEH without filter function"); + const MCExpr *FilterOrNull = + create32bitRef(BA ? Asm->getSymbol(F) : nullptr); + const MCExpr *ExceptOrFinally = create32bitRef( + BA ? Asm->GetBlockAddressSymbol(BA) : Asm->getSymbol(F)); + + OS.EmitIntValue(EnclosingLevel, 4); + OS.EmitValue(FilterOrNull, 4); + OS.EmitValue(ExceptOrFinally, 4); + + // The next state unwinds to this state. + EnclosingLevel = CurState; + CurState++; + } + } +} |
