#include "X86.h"
#include "llvm/Analysis/LibCallSemantics.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/WinEHFuncInfo.h"
#include "llvm/IR/Dominators.h"
private:
void emitExceptionRegistrationRecord(Function *F);
- void linkExceptionRegistration(IRBuilder<> &Builder, Value *RegNode,
- Value *Handler);
- void unlinkExceptionRegistration(IRBuilder<> &Builder, Value *RegNode);
+ void linkExceptionRegistration(IRBuilder<> &Builder, Function *Handler);
+ void unlinkExceptionRegistration(IRBuilder<> &Builder);
+ void addCXXStateStores(Function &F, MachineModuleInfo &MMI);
+ void addSEHStateStores(Function &F, MachineModuleInfo &MMI);
+ void addCXXStateStoresToFunclet(Value *ParentRegNode, WinEHFuncInfo &FuncInfo,
+ Function &F, int BaseState);
+ void insertStateNumberStore(Value *ParentRegNode, Instruction *IP, int State);
+
+ Value *emitEHLSDA(IRBuilder<> &Builder, Function *F);
+
+ Function *generateLSDAInEAXThunk(Function *ParentFunc);
+
+ int escapeRegNode(Function &F);
// Module-level type getters.
- Type *getEHRegistrationType();
- Type *getSEH3RegistrationType();
- Type *getSEH4RegistrationType();
- Type *getCXXEH3RegistrationType();
+ Type *getEHLinkRegistrationType();
+ Type *getSEHRegistrationType();
+ Type *getCXXEHRegistrationType();
// Per-module data.
Module *TheModule = nullptr;
- StructType *EHRegistrationTy = nullptr;
- StructType *CXXEH3RegistrationTy = nullptr;
- StructType *SEH3RegistrationTy = nullptr;
- StructType *SEH4RegistrationTy = nullptr;
+ StructType *EHLinkRegistrationTy = nullptr;
+ StructType *CXXEHRegistrationTy = nullptr;
+ StructType *SEHRegistrationTy = nullptr;
+ Function *FrameRecover = nullptr;
+ Function *FrameAddress = nullptr;
+ Function *FrameEscape = nullptr;
// Per-function state
EHPersonality Personality = EHPersonality::Unknown;
Function *PersonalityFn = nullptr;
+
+ /// The stack allocation containing all EH data, including the link in the
+ /// fs:00 chain and the current state.
+ AllocaInst *RegNode = nullptr;
+
+ /// Struct type of RegNode. Used for GEPing.
+ Type *RegNodeTy = nullptr;
+
+ /// The index of the state field of RegNode.
+ int StateFieldIndex = ~0U;
+
+ /// The linked list node subobject inside of RegNode.
+ Value *Link = nullptr;
};
}
bool WinEHStatePass::doInitialization(Module &M) {
TheModule = &M;
+ FrameEscape = Intrinsic::getDeclaration(TheModule, Intrinsic::frameescape);
+ FrameRecover = Intrinsic::getDeclaration(TheModule, Intrinsic::framerecover);
+ FrameAddress = Intrinsic::getDeclaration(TheModule, Intrinsic::frameaddress);
return false;
}
bool WinEHStatePass::doFinalization(Module &M) {
assert(TheModule == &M);
TheModule = nullptr;
- EHRegistrationTy = nullptr;
- CXXEH3RegistrationTy = nullptr;
- SEH3RegistrationTy = nullptr;
- SEH4RegistrationTy = nullptr;
+ EHLinkRegistrationTy = nullptr;
+ CXXEHRegistrationTy = nullptr;
+ SEHRegistrationTy = nullptr;
+ FrameEscape = nullptr;
+ FrameRecover = nullptr;
+ FrameAddress = nullptr;
return false;
}
}
bool WinEHStatePass::runOnFunction(Function &F) {
+ // If this is an outlined handler, don't do anything. We'll do state insertion
+ // for it in the parent.
+ StringRef WinEHParentName =
+ F.getFnAttribute("wineh-parent").getValueAsString();
+ if (WinEHParentName != F.getName() && !WinEHParentName.empty())
+ return false;
+
// Check the personality. Do nothing if this is not an MSVC personality.
- LandingPadInst *LP = nullptr;
- for (BasicBlock &BB : F) {
- LP = BB.getLandingPadInst();
- if (LP)
- break;
- }
- if (!LP)
+ if (!F.hasPersonalityFn())
return false;
PersonalityFn =
- dyn_cast<Function>(LP->getPersonalityFn()->stripPointerCasts());
+ dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
if (!PersonalityFn)
return false;
Personality = classifyEHPersonality(PersonalityFn);
if (!isMSVCEHPersonality(Personality))
return false;
+ // Disable frame pointer elimination in this function.
+ // FIXME: Do the nested handlers need to keep the parent ebp in ebp, or can we
+ // use an arbitrary register?
+ F.addFnAttr("no-frame-pointer-elim", "true");
+
emitExceptionRegistrationRecord(&F);
- // FIXME: State insertion.
+
+ auto *MMIPtr = getAnalysisIfAvailable<MachineModuleInfo>();
+ assert(MMIPtr && "MachineModuleInfo should always be available");
+ MachineModuleInfo &MMI = *MMIPtr;
+ switch (Personality) {
+ default: llvm_unreachable("unexpected personality function");
+ case EHPersonality::MSVC_CXX: addCXXStateStores(F, MMI); break;
+ case EHPersonality::MSVC_X86SEH: addSEHStateStores(F, MMI); break;
+ }
// Reset per-function state.
PersonalityFn = nullptr;
}
/// Get the common EH registration subobject:
+/// typedef _EXCEPTION_DISPOSITION (*PEXCEPTION_ROUTINE)(
+/// _EXCEPTION_RECORD *, void *, _CONTEXT *, void *);
/// struct EHRegistrationNode {
/// EHRegistrationNode *Next;
-/// EXCEPTION_DISPOSITION (*Handler)(...);
+/// PEXCEPTION_ROUTINE Handler;
/// };
-Type *WinEHStatePass::getEHRegistrationType() {
- if (EHRegistrationTy)
- return EHRegistrationTy;
+Type *WinEHStatePass::getEHLinkRegistrationType() {
+ if (EHLinkRegistrationTy)
+ return EHLinkRegistrationTy;
LLVMContext &Context = TheModule->getContext();
- EHRegistrationTy = StructType::create(Context, "EHRegistrationNode");
+ EHLinkRegistrationTy = StructType::create(Context, "EHRegistrationNode");
Type *FieldTys[] = {
- EHRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next
+ EHLinkRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next
Type::getInt8PtrTy(Context) // EXCEPTION_DISPOSITION (*Handler)(...)
};
- EHRegistrationTy->setBody(FieldTys, false);
- return EHRegistrationTy;
+ EHLinkRegistrationTy->setBody(FieldTys, false);
+ return EHLinkRegistrationTy;
}
/// The __CxxFrameHandler3 registration node:
/// EHRegistrationNode SubRecord;
/// int32_t TryLevel;
/// };
-Type *WinEHStatePass::getCXXEH3RegistrationType() {
- if (CXXEH3RegistrationTy)
- return CXXEH3RegistrationTy;
+Type *WinEHStatePass::getCXXEHRegistrationType() {
+ if (CXXEHRegistrationTy)
+ return CXXEHRegistrationTy;
LLVMContext &Context = TheModule->getContext();
Type *FieldTys[] = {
Type::getInt8PtrTy(Context), // void *SavedESP
- getEHRegistrationType(), // EHRegistrationNode SubRecord
+ getEHLinkRegistrationType(), // EHRegistrationNode SubRecord
Type::getInt32Ty(Context) // int32_t TryLevel
};
- CXXEH3RegistrationTy =
+ CXXEHRegistrationTy =
StructType::create(FieldTys, "CXXExceptionRegistration");
- return CXXEH3RegistrationTy;
-}
-
-/// The _except_handler3 registration node:
-/// struct EH3ExceptionRegistration {
-/// EHRegistrationNode SubRecord;
-/// void *ScopeTable;
-/// int32_t TryLevel;
-/// };
-Type *WinEHStatePass::getSEH3RegistrationType() {
- if (SEH3RegistrationTy)
- return SEH3RegistrationTy;
- LLVMContext &Context = TheModule->getContext();
- Type *FieldTys[] = {
- getEHRegistrationType(), // EHRegistrationNode SubRecord
- Type::getInt8PtrTy(Context), // void *ScopeTable
- Type::getInt32Ty(Context) // int32_t TryLevel
- };
- SEH3RegistrationTy = StructType::create(FieldTys, "EH3ExceptionRegistration");
- return SEH3RegistrationTy;
+ return CXXEHRegistrationTy;
}
-/// The _except_handler4 registration node:
+/// The _except_handler3/4 registration node:
/// struct EH4ExceptionRegistration {
/// void *SavedESP;
/// _EXCEPTION_POINTERS *ExceptionPointers;
/// int32_t EncodedScopeTable;
/// int32_t TryLevel;
/// };
-Type *WinEHStatePass::getSEH4RegistrationType() {
- if (SEH4RegistrationTy)
- return SEH4RegistrationTy;
+Type *WinEHStatePass::getSEHRegistrationType() {
+ if (SEHRegistrationTy)
+ return SEHRegistrationTy;
LLVMContext &Context = TheModule->getContext();
Type *FieldTys[] = {
Type::getInt8PtrTy(Context), // void *SavedESP
Type::getInt8PtrTy(Context), // void *ExceptionPointers
- getEHRegistrationType(), // EHRegistrationNode SubRecord
+ getEHLinkRegistrationType(), // EHRegistrationNode SubRecord
Type::getInt32Ty(Context), // int32_t EncodedScopeTable
Type::getInt32Ty(Context) // int32_t TryLevel
};
- SEH4RegistrationTy = StructType::create(FieldTys, "EH4ExceptionRegistration");
- return SEH4RegistrationTy;
+ SEHRegistrationTy = StructType::create(FieldTys, "SEHExceptionRegistration");
+ return SEHRegistrationTy;
}
// Emit an exception registration record. These are stack allocations with the
StringRef PersonalityName = PersonalityFn->getName();
IRBuilder<> Builder(&F->getEntryBlock(), F->getEntryBlock().begin());
Type *Int8PtrType = Builder.getInt8PtrTy();
- Value *SubRecord = nullptr;
- if (PersonalityName == "__CxxFrameHandler3") {
- Type *RegNodeTy = getCXXEH3RegistrationType();
- Value *RegNode = Builder.CreateAlloca(RegNodeTy);
- // FIXME: We can skip this in -GS- mode, when we figure that out.
+ if (Personality == EHPersonality::MSVC_CXX) {
+ RegNodeTy = getCXXEHRegistrationType();
+ RegNode = Builder.CreateAlloca(RegNodeTy);
// SavedESP = llvm.stacksave()
Value *SP = Builder.CreateCall(
Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {});
Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
// TryLevel = -1
- Builder.CreateStore(Builder.getInt32(-1),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 2));
- // FIXME: 'Personality' is incorrect here. We need to generate a trampoline
- // that effectively gets the LSDA.
- SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
- linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
- } else if (PersonalityName == "_except_handler3") {
- Type *RegNodeTy = getSEH3RegistrationType();
- Value *RegNode = Builder.CreateAlloca(RegNodeTy);
- // TryLevel = -1
- Builder.CreateStore(Builder.getInt32(-1),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 2));
- // FIXME: Generalize llvm.eh.sjljl.lsda for this.
- // ScopeTable = nullptr
- Builder.CreateStore(Constant::getNullValue(Int8PtrType),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
- SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 0);
- linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
- } else if (PersonalityName == "_except_handler4") {
- Type *RegNodeTy = getSEH4RegistrationType();
- Value *RegNode = Builder.CreateAlloca(RegNodeTy);
+ StateFieldIndex = 2;
+ insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1);
+ // Handler = __ehhandler$F
+ Function *Trampoline = generateLSDAInEAXThunk(F);
+ Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
+ linkExceptionRegistration(Builder, Trampoline);
+ } else if (Personality == EHPersonality::MSVC_X86SEH) {
+ // If _except_handler4 is in use, some additional guard checks and prologue
+ // stuff is required.
+ bool UseStackGuard = (PersonalityName == "_except_handler4");
+ RegNodeTy = getSEHRegistrationType();
+ RegNode = Builder.CreateAlloca(RegNodeTy);
// SavedESP = llvm.stacksave()
Value *SP = Builder.CreateCall(
Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {});
Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
- // TryLevel = -2
- Builder.CreateStore(Builder.getInt32(-2),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 4));
- // FIXME: Generalize llvm.eh.sjljl.lsda for this, and then do the stack
- // cookie xor.
- // ScopeTable = nullptr
- Builder.CreateStore(Builder.getInt32(0),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 3));
- SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 2);
- linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
+ // TryLevel = -2 / -1
+ StateFieldIndex = 4;
+ insertStateNumberStore(RegNode, Builder.GetInsertPoint(),
+ UseStackGuard ? -2 : -1);
+ // ScopeTable = llvm.x86.seh.lsda(F)
+ Value *FI8 = Builder.CreateBitCast(F, Int8PtrType);
+ Value *LSDA = Builder.CreateCall(
+ Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_lsda), FI8);
+ Type *Int32Ty = Type::getInt32Ty(TheModule->getContext());
+ LSDA = Builder.CreatePtrToInt(LSDA, Int32Ty);
+ // If using _except_handler4, xor the address of the table with
+ // __security_cookie.
+ if (UseStackGuard) {
+ Value *Cookie =
+ TheModule->getOrInsertGlobal("__security_cookie", Int32Ty);
+ Value *Val = Builder.CreateLoad(Int32Ty, Cookie);
+ LSDA = Builder.CreateXor(LSDA, Val);
+ }
+ Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 3));
+ Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 2);
+ linkExceptionRegistration(Builder, PersonalityFn);
} else {
llvm_unreachable("unexpected personality function");
}
- // FIXME: Insert an unlink before all returns.
+ // Insert an unlink before all returns.
for (BasicBlock &BB : *F) {
TerminatorInst *T = BB.getTerminator();
if (!isa<ReturnInst>(T))
continue;
Builder.SetInsertPoint(T);
- unlinkExceptionRegistration(Builder, SubRecord);
+ unlinkExceptionRegistration(Builder);
}
}
+Value *WinEHStatePass::emitEHLSDA(IRBuilder<> &Builder, Function *F) {
+ Value *FI8 = Builder.CreateBitCast(F, Type::getInt8PtrTy(F->getContext()));
+ return Builder.CreateCall(
+ Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_lsda), FI8);
+}
+
+/// Generate a thunk that puts the LSDA of ParentFunc in EAX and then calls
+/// PersonalityFn, forwarding the parameters passed to PEXCEPTION_ROUTINE:
+/// typedef _EXCEPTION_DISPOSITION (*PEXCEPTION_ROUTINE)(
+/// _EXCEPTION_RECORD *, void *, _CONTEXT *, void *);
+/// We essentially want this code:
+/// movl $lsda, %eax
+/// jmpl ___CxxFrameHandler3
+Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) {
+ LLVMContext &Context = ParentFunc->getContext();
+ Type *Int32Ty = Type::getInt32Ty(Context);
+ Type *Int8PtrType = Type::getInt8PtrTy(Context);
+ Type *ArgTys[5] = {Int8PtrType, Int8PtrType, Int8PtrType, Int8PtrType,
+ Int8PtrType};
+ FunctionType *TrampolineTy =
+ FunctionType::get(Int32Ty, makeArrayRef(&ArgTys[0], 4),
+ /*isVarArg=*/false);
+ FunctionType *TargetFuncTy =
+ FunctionType::get(Int32Ty, makeArrayRef(&ArgTys[0], 5),
+ /*isVarArg=*/false);
+ Function *Trampoline = Function::Create(
+ TrampolineTy, GlobalValue::InternalLinkage,
+ Twine("__ehhandler$") + ParentFunc->getName(), TheModule);
+ BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", Trampoline);
+ IRBuilder<> Builder(EntryBB);
+ Value *LSDA = emitEHLSDA(Builder, ParentFunc);
+ Value *CastPersonality =
+ Builder.CreateBitCast(PersonalityFn, TargetFuncTy->getPointerTo());
+ auto AI = Trampoline->arg_begin();
+ Value *Args[5] = {LSDA, AI++, AI++, AI++, AI++};
+ CallInst *Call = Builder.CreateCall(CastPersonality, Args);
+ // Can't use musttail due to prototype mismatch, but we can use tail.
+ Call->setTailCall(true);
+ // Set inreg so we pass it in EAX.
+ Call->addAttribute(1, Attribute::InReg);
+ Builder.CreateRet(Call);
+ return Trampoline;
+}
+
void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder,
- Value *RegNode, Value *Handler) {
- Type *RegNodeTy = getEHRegistrationType();
+ Function *Handler) {
+ // Emit the .safeseh directive for this function.
+ Handler->addFnAttr("safeseh");
+
+ Type *LinkTy = getEHLinkRegistrationType();
// Handler = Handler
- Handler = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
- Builder.CreateStore(Handler, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
+ Value *HandlerI8 = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
+ Builder.CreateStore(HandlerI8, Builder.CreateStructGEP(LinkTy, Link, 1));
// Next = [fs:00]
Constant *FSZero =
- Constant::getNullValue(RegNodeTy->getPointerTo()->getPointerTo(257));
+ Constant::getNullValue(LinkTy->getPointerTo()->getPointerTo(257));
Value *Next = Builder.CreateLoad(FSZero);
- Builder.CreateStore(Next, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
- // [fs:00] = RegNode
- Builder.CreateStore(RegNode, FSZero);
+ Builder.CreateStore(Next, Builder.CreateStructGEP(LinkTy, Link, 0));
+ // [fs:00] = Link
+ Builder.CreateStore(Link, FSZero);
}
-void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder,
- Value *RegNode) {
- // Clone RegNode into the current BB for better address mode folding.
- if (auto *GEP = dyn_cast<GetElementPtrInst>(RegNode)) {
+void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder) {
+ // Clone Link into the current BB for better address mode folding.
+ if (auto *GEP = dyn_cast<GetElementPtrInst>(Link)) {
GEP = cast<GetElementPtrInst>(GEP->clone());
Builder.Insert(GEP);
- RegNode = GEP;
+ Link = GEP;
}
- Type *RegNodeTy = getEHRegistrationType();
- // [fs:00] = RegNode->Next
+ Type *LinkTy = getEHLinkRegistrationType();
+ // [fs:00] = Link->Next
Value *Next =
- Builder.CreateLoad(Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
+ Builder.CreateLoad(Builder.CreateStructGEP(LinkTy, Link, 0));
Constant *FSZero =
- Constant::getNullValue(RegNodeTy->getPointerTo()->getPointerTo(257));
+ Constant::getNullValue(LinkTy->getPointerTo()->getPointerTo(257));
Builder.CreateStore(Next, FSZero);
}
+
+void WinEHStatePass::addCXXStateStores(Function &F, MachineModuleInfo &MMI) {
+ WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(&F);
+ calculateWinCXXEHStateNumbers(&F, FuncInfo);
+
+ // The base state for the parent is -1.
+ addCXXStateStoresToFunclet(RegNode, FuncInfo, F, -1);
+
+ // Set up RegNodeEscapeIndex
+ int RegNodeEscapeIndex = escapeRegNode(F);
+
+ // Only insert stores in catch handlers.
+ Constant *FI8 =
+ ConstantExpr::getBitCast(&F, Type::getInt8PtrTy(TheModule->getContext()));
+ for (auto P : FuncInfo.HandlerBaseState) {
+ Function *Handler = const_cast<Function *>(P.first);
+ int BaseState = P.second;
+ IRBuilder<> Builder(&Handler->getEntryBlock(),
+ Handler->getEntryBlock().begin());
+ // FIXME: Find and reuse such a call if present.
+ Value *ParentFP = Builder.CreateCall(FrameAddress, {Builder.getInt32(1)});
+ Value *RecoveredRegNode = Builder.CreateCall(
+ FrameRecover, {FI8, ParentFP, Builder.getInt32(RegNodeEscapeIndex)});
+ RecoveredRegNode =
+ Builder.CreateBitCast(RecoveredRegNode, RegNodeTy->getPointerTo(0));
+ addCXXStateStoresToFunclet(RecoveredRegNode, FuncInfo, *Handler, BaseState);
+ }
+}
+
+/// Escape RegNode so that we can access it from child handlers. Find the call
+/// to frameescape, if any, in the entry block and append RegNode to the list
+/// of arguments.
+int WinEHStatePass::escapeRegNode(Function &F) {
+ // Find the call to frameescape and extract its arguments.
+ IntrinsicInst *EscapeCall = nullptr;
+ for (Instruction &I : F.getEntryBlock()) {
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
+ if (II && II->getIntrinsicID() == Intrinsic::frameescape) {
+ EscapeCall = II;
+ break;
+ }
+ }
+ SmallVector<Value *, 8> Args;
+ if (EscapeCall) {
+ auto Ops = EscapeCall->arg_operands();
+ Args.append(Ops.begin(), Ops.end());
+ }
+ Args.push_back(RegNode);
+
+ // Replace the call (if it exists) with new one. Otherwise, insert at the end
+ // of the entry block.
+ IRBuilder<> Builder(&F.getEntryBlock(),
+ EscapeCall ? EscapeCall : F.getEntryBlock().end());
+ Builder.CreateCall(FrameEscape, Args);
+ if (EscapeCall)
+ EscapeCall->eraseFromParent();
+ return Args.size() - 1;
+}
+
+void WinEHStatePass::addCXXStateStoresToFunclet(Value *ParentRegNode,
+ WinEHFuncInfo &FuncInfo,
+ Function &F, int BaseState) {
+ // Iterate all the instructions and emit state number stores.
+ for (BasicBlock &BB : F) {
+ for (Instruction &I : BB) {
+ if (auto *CI = dyn_cast<CallInst>(&I)) {
+ // Possibly throwing call instructions have no actions to take after
+ // an unwind. Ensure they are in the -1 state.
+ if (CI->doesNotThrow())
+ continue;
+ insertStateNumberStore(ParentRegNode, CI, BaseState);
+ } else if (auto *II = dyn_cast<InvokeInst>(&I)) {
+ // Look up the state number of the landingpad this unwinds to.
+ LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst();
+ // FIXME: Why does this assertion fail?
+ //assert(FuncInfo.LandingPadStateMap.count(LPI) && "LP has no state!");
+ int State = FuncInfo.LandingPadStateMap[LPI];
+ insertStateNumberStore(ParentRegNode, II, State);
+ }
+ }
+ }
+}
+
+/// Assign every distinct landingpad a unique state number for SEH. Unlike C++
+/// EH, we can use this very simple algorithm while C++ EH cannot because catch
+/// handlers aren't outlined and the runtime doesn't have to figure out which
+/// catch handler frame to unwind to.
+/// FIXME: __finally blocks are outlined, so this approach may break down there.
+void WinEHStatePass::addSEHStateStores(Function &F, MachineModuleInfo &MMI) {
+ WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(&F);
+
+ // Remember and return the index that we used. We save it in WinEHFuncInfo so
+ // that we can lower llvm.x86.seh.exceptioninfo later in filter functions
+ // without too much trouble.
+ int RegNodeEscapeIndex = escapeRegNode(F);
+ FuncInfo.EHRegNodeEscapeIndex = RegNodeEscapeIndex;
+
+ // Iterate all the instructions and emit state number stores.
+ int CurState = 0;
+ SmallPtrSet<BasicBlock *, 4> ExceptBlocks;
+ for (BasicBlock &BB : F) {
+ for (auto I = BB.begin(), E = BB.end(); I != E; ++I) {
+ if (auto *CI = dyn_cast<CallInst>(I)) {
+ auto *Intrin = dyn_cast<IntrinsicInst>(CI);
+ if (Intrin) {
+ // Calls that "don't throw" are considered to be able to throw asynch
+ // exceptions, but intrinsics cannot.
+ continue;
+ }
+ insertStateNumberStore(RegNode, CI, -1);
+ } else if (auto *II = dyn_cast<InvokeInst>(I)) {
+ // Look up the state number of the landingpad this unwinds to.
+ LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst();
+ auto InsertionPair =
+ FuncInfo.LandingPadStateMap.insert(std::make_pair(LPI, CurState));
+ auto Iter = InsertionPair.first;
+ int &State = Iter->second;
+ bool Inserted = InsertionPair.second;
+ if (Inserted) {
+ // Each action consumes a state number.
+ auto *EHActions = cast<IntrinsicInst>(LPI->getNextNode());
+ SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
+ parseEHActions(EHActions, ActionList);
+ assert(!ActionList.empty());
+ CurState += ActionList.size();
+ State += ActionList.size() - 1;
+
+ // Remember all the __except block targets.
+ for (auto &Handler : ActionList) {
+ if (auto *CH = dyn_cast<CatchHandler>(Handler.get())) {
+ auto *BA = cast<BlockAddress>(CH->getHandlerBlockOrFunc());
+ ExceptBlocks.insert(BA->getBasicBlock());
+ }
+ }
+ }
+ insertStateNumberStore(RegNode, II, State);
+ }
+ }
+ }
+
+ // Insert llvm.stackrestore into each __except block.
+ Function *StackRestore =
+ Intrinsic::getDeclaration(TheModule, Intrinsic::stackrestore);
+ for (BasicBlock *ExceptBB : ExceptBlocks) {
+ IRBuilder<> Builder(ExceptBB->begin());
+ Value *SP =
+ Builder.CreateLoad(Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
+ Builder.CreateCall(StackRestore, {SP});
+ }
+}
+
+void WinEHStatePass::insertStateNumberStore(Value *ParentRegNode,
+ Instruction *IP, int State) {
+ IRBuilder<> Builder(IP);
+ Value *StateField =
+ Builder.CreateStructGEP(RegNodeTy, ParentRegNode, StateFieldIndex);
+ Builder.CreateStore(Builder.getInt32(State), StateField);
+}
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