diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp | 433 |
1 files changed, 415 insertions, 18 deletions
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp index 0f0ad75..dc6df9c 100644 --- a/contrib/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp +++ b/contrib/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp @@ -19,6 +19,7 @@ #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" @@ -48,8 +49,6 @@ Win64Exception::~Win64Exception() {} void Win64Exception::endModule() { } -/// beginFunction - Gather pre-function exception information. Assumes it's -/// being emitted immediately after the function entry point. void Win64Exception::beginFunction(const MachineFunction *MF) { shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false; @@ -60,7 +59,7 @@ void Win64Exception::beginFunction(const MachineFunction *MF) { const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); unsigned PerEncoding = TLOF.getPersonalityEncoding(); - const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()]; + const Function *Per = MF->getMMI().getPersonality(); shouldEmitPersonality = hasLandingPads && PerEncoding != dwarf::DW_EH_PE_omit && Per; @@ -69,39 +68,437 @@ void Win64Exception::beginFunction(const MachineFunction *MF) { shouldEmitLSDA = shouldEmitPersonality && LSDAEncoding != dwarf::DW_EH_PE_omit; + + // 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. + const Function *F = MF->getFunction(); + const Function *ParentF = MMI->getWinEHParent(F); + 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 (!shouldEmitPersonality && !shouldEmitMoves) return; - Asm->OutStreamer.EmitWinCFIStartProc(Asm->CurrentFnSym); + Asm->OutStreamer->EmitWinCFIStartProc(Asm->CurrentFnSym); if (!shouldEmitPersonality) return; const MCSymbol *PersHandlerSym = TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI); - Asm->OutStreamer.EmitWinEHHandler(PersHandlerSym, true, true); - - Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin", - Asm->getFunctionNumber())); + Asm->OutStreamer->EmitWinEHHandler(PersHandlerSym, true, true); } /// endFunction - Gather and emit post-function exception information. /// -void Win64Exception::endFunction(const MachineFunction *) { +void Win64Exception::endFunction(const MachineFunction *MF) { if (!shouldEmitPersonality && !shouldEmitMoves) return; - Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end", - Asm->getFunctionNumber())); + EHPersonality Per = MMI->getPersonalityType(); - // Map all labels and get rid of any dead landing pads. - MMI->TidyLandingPads(); + // 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) { - Asm->OutStreamer.PushSection(); - Asm->OutStreamer.EmitWinEHHandlerData(); - emitExceptionTable(); - Asm->OutStreamer.PopSection(); + Asm->OutStreamer->PushSection(); + + // Emit an UNWIND_INFO struct describing the prologue. + Asm->OutStreamer->EmitWinEHHandlerData(); + + // 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_CXX) + emitCXXFrameHandler3Table(MF); + else + emitExceptionTable(); + + Asm->OutStreamer->PopSection(); + } + Asm->OutStreamer->EmitWinCFIEndProc(); +} + +const MCExpr *Win64Exception::createImageRel32(const MCSymbol *Value) { + if (!Value) + return MCConstantExpr::Create(0, Asm->OutContext); + return MCSymbolRefExpr::Create(Value, MCSymbolRefExpr::VK_COFF_IMGREL32, + Asm->OutContext); +} + +const MCExpr *Win64Exception::createImageRel32(const GlobalValue *GV) { + if (!GV) + return MCConstantExpr::Create(0, Asm->OutContext); + return createImageRel32(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 Win64Exception::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 = + createImageRel32(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(createImageRel32(CSE.EndLabel), + MCConstantExpr::Create(1, Asm->OutContext), + Asm->OutContext); + } else { + End = createImageRel32(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(createImageRel32(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( + createImageRel32(Asm->GetBlockAddressSymbol(BA)), 4); + else + Asm->OutStreamer->EmitIntValue(0, 4); + } + } +} + +void Win64Exception::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 = + Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", ParentLinkageName)); + OS.EmitValue(createImageRel32(FuncInfoXData), 4); + + // 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]; + } + } + + // Defer emission until we've visited the parent function and all the catch + // handlers. Cleanups don't contribute to the ip2state table yet, so don't + // count them. + if (ParentF != F && !FuncInfo.CatchHandlerMaxState.count(F)) + return; + ++FuncInfo.NumIPToStateFuncsVisited; + if (FuncInfo.NumIPToStateFuncsVisited != FuncInfo.CatchHandlerMaxState.size()) + return; + + 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; + // IPToStateMapEntry *IPToStateMap; + // uint32_t UnwindHelp; // (x64/ARM 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(createImageRel32(UnwindMapXData), 4); // UnwindMap + OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4); // NumTryBlocks + OS.EmitValue(createImageRel32(TryBlockMapXData), 4); // TryBlockMap + OS.EmitIntValue(FuncInfo.IPToStateList.size(), 4); // IPMapEntries + OS.EmitValue(createImageRel32(IPToStateXData), 4); // IPToStateMap + 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(createImageRel32(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(createImageRel32(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) { + MCSymbol *ParentFrameOffset = + Asm->OutContext.getOrCreateParentFrameOffsetSymbol( + GlobalValue::getRealLinkageName(HT.Handler->getName())); + const MCSymbolRefExpr *ParentFrameOffsetRef = MCSymbolRefExpr::Create( + ParentFrameOffset, MCSymbolRefExpr::VK_None, Asm->OutContext); + + // 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(createImageRel32(HT.TypeDescriptor), 4); // Type + OS.EmitValue(FrameAllocOffsetRef, 4); // CatchObjOffset + OS.EmitValue(createImageRel32(HT.Handler), 4); // Handler + OS.EmitValue(ParentFrameOffsetRef, 4); // ParentFrameOffset + } + } + } + + // IPToStateMapEntry { + // void *IP; + // int32_t State; + // }; + if (IPToStateXData) { + OS.EmitLabel(IPToStateXData); + for (auto &IPStatePair : FuncInfo.IPToStateList) { + OS.EmitValue(createImageRel32(IPStatePair.first), 4); // IP + OS.EmitIntValue(IPStatePair.second, 4); // State + } } - Asm->OutStreamer.EmitWinCFIEndProc(); } |
