From cde33036ed74db02088f5e3558afa33384cc4a13 Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Mon, 30 Mar 2015 22:58:10 +0000 Subject: [WinEH] Run cleanup handlers when an exception is thrown Generate tables in the .xdata section representing what actions to take when an exception is thrown. This currently fills in state for cleanups, catch handlers are still unfinished. llvm-svn: 233636 --- llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp | 212 ++++++++++++++++++++++++- 1 file changed, 210 insertions(+), 2 deletions(-) (limited to 'llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp') diff --git a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp index 7d76eaddb56..974e94dcb6a 100644 --- a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp +++ b/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" @@ -82,7 +83,7 @@ void Win64Exception::beginFunction(const MachineFunction *MF) { /// endFunction - Gather and emit post-function exception information. /// -void Win64Exception::endFunction(const MachineFunction *) { +void Win64Exception::endFunction(const MachineFunction *MF) { if (!shouldEmitPersonality && !shouldEmitMoves) return; @@ -100,6 +101,8 @@ void Win64Exception::endFunction(const MachineFunction *) { EHPersonality Per = MMI->getPersonalityType(); if (Per == EHPersonality::MSVC_Win64SEH) emitCSpecificHandlerTable(); + else if (Per == EHPersonality::MSVC_CXX) + emitCXXFrameHandler3Table(MF); else emitExceptionTable(); @@ -108,11 +111,19 @@ void Win64Exception::endFunction(const MachineFunction *) { Asm->OutStreamer.EmitWinCFIEndProc(); } -const MCSymbolRefExpr *Win64Exception::createImageRel32(const MCSymbol *Value) { +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 @@ -237,3 +248,200 @@ void Win64Exception::emitCSpecificHandlerTable() { } } } + +void Win64Exception::emitCXXFrameHandler3Table(const MachineFunction *MF) { + const Function *F = MF->getFunction(); + const Function *ParentF = MMI->getWinEHParent(F); + auto &OS = Asm->OutStreamer; + + 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 LandingPads; + const std::vector &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; + + WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF); + + int LastEHState = -2; + + // The parent function and the catch handlers contribute to the 'ip2state' + // table. + 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!"); + + if (SawPotentiallyThrowing) { + 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]; + } + } + + if (ParentF != F) + 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 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); + + assert(TBME.TryLow <= TBME.TryHigh); + assert(TBME.CatchHigh > TBME.TryHigh); + OS.EmitIntValue(TBME.TryLow, 4); // TryLow + OS.EmitIntValue(TBME.TryHigh, 4); // TryHigh + OS.EmitIntValue(TBME.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) { + OS.EmitIntValue(HT.Adjectives, 4); // Adjectives + OS.EmitValue(createImageRel32(HT.TypeDescriptor), 4); // Type + OS.EmitIntValue(0, 4); // CatchObjOffset + OS.EmitValue(createImageRel32(HT.Handler), 4); // Handler + OS.EmitIntValue(0, 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 + } + } +} -- cgit v1.2.3