#define DEBUG_TYPE "winehstate"
+namespace llvm { void initializeWinEHStatePassPass(PassRegistry &); }
+
namespace {
class WinEHStatePass : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid.
- WinEHStatePass() : FunctionPass(ID) {}
+ WinEHStatePass() : FunctionPass(ID) {
+ initializeWinEHStatePassPass(*PassRegistry::getPassRegistry());
+ }
bool runOnFunction(Function &Fn) override;
private:
void emitExceptionRegistrationRecord(Function *F);
- void linkExceptionRegistration(IRBuilder<> &Builder, Value *Handler);
+ void linkExceptionRegistration(IRBuilder<> &Builder, Function *Handler);
void unlinkExceptionRegistration(IRBuilder<> &Builder);
- void addCXXStateStores(Function &F, MachineModuleInfo &MMI);
- void addCXXStateStoresToFunclet(Value *ParentRegNode, WinEHFuncInfo &FuncInfo,
- Function &F, int BaseState);
+ void addCXXStateStores(Function &F, WinEHFuncInfo &FuncInfo);
+ void addSEHStateStores(Function &F, WinEHFuncInfo &FuncInfo);
+ void addStateStoresToFunclet(Value *ParentRegNode, WinEHFuncInfo &FuncInfo,
+ Function &F, int BaseState);
void insertStateNumberStore(Value *ParentRegNode, Instruction *IP, int State);
+ void insertRestoreFrame(BasicBlock *BB);
Value *emitEHLSDA(IRBuilder<> &Builder, Function *F);
StructType *EHLinkRegistrationTy = nullptr;
StructType *CXXEHRegistrationTy = nullptr;
StructType *SEHRegistrationTy = nullptr;
+ Function *FrameRecover = nullptr;
+ Function *FrameAddress = nullptr;
+ Function *FrameEscape = nullptr;
+ Function *RestoreFrame = nullptr;
// Per-function state
EHPersonality Personality = EHPersonality::Unknown;
char WinEHStatePass::ID = 0;
+INITIALIZE_PASS(WinEHStatePass, "x86-winehstate",
+ "Insert stores for EH state numbers", false, false)
+
bool WinEHStatePass::doInitialization(Module &M) {
TheModule = &M;
+ FrameEscape = Intrinsic::getDeclaration(TheModule, Intrinsic::localescape);
+ FrameRecover = Intrinsic::getDeclaration(TheModule, Intrinsic::localrecover);
+ FrameAddress = Intrinsic::getDeclaration(TheModule, Intrinsic::frameaddress);
+ RestoreFrame =
+ Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_restoreframe);
return false;
}
EHLinkRegistrationTy = nullptr;
CXXEHRegistrationTy = nullptr;
SEHRegistrationTy = nullptr;
+ FrameEscape = nullptr;
+ FrameRecover = nullptr;
+ FrameAddress = nullptr;
return false;
}
void WinEHStatePass::getAnalysisUsage(AnalysisUsage &AU) const {
// This pass should only insert a stack allocation, memory accesses, and
- // framerecovers.
+ // localrecovers.
AU.setPreservesCFG();
}
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;
+ // Skip this function if there are no EH pads and we aren't using IR-level
+ // outlining.
+ if (WinEHParentName.empty()) {
+ bool HasPads = false;
+ for (BasicBlock &BB : F) {
+ if (BB.isEHPad()) {
+ HasPads = true;
+ break;
+ }
+ }
+ if (!HasPads)
+ 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?
emitExceptionRegistrationRecord(&F);
- auto *MMIPtr = getAnalysisIfAvailable<MachineModuleInfo>();
- assert(MMIPtr && "MachineModuleInfo should always be available");
- MachineModuleInfo &MMI = *MMIPtr;
- if (Personality == EHPersonality::MSVC_CXX) {
- addCXXStateStores(F, MMI);
+ auto *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
+ // If MMI is null, create our own WinEHFuncInfo. This only happens in opt
+ // tests.
+ std::unique_ptr<WinEHFuncInfo> FuncInfoPtr;
+ if (!MMI)
+ FuncInfoPtr.reset(new WinEHFuncInfo());
+ WinEHFuncInfo &FuncInfo =
+ *(MMI ? &MMI->getWinEHFuncInfo(&F) : FuncInfoPtr.get());
+
+ FuncInfo.EHRegNode = RegNode;
+
+ switch (Personality) {
+ default: llvm_unreachable("unexpected personality function");
+ case EHPersonality::MSVC_CXX:
+ addCXXStateStores(F, FuncInfo);
+ break;
+ case EHPersonality::MSVC_X86SEH:
+ addSEHStateStores(F, FuncInfo);
+ break;
}
// Reset per-function state.
if (Personality == EHPersonality::MSVC_CXX) {
RegNodeTy = getCXXEHRegistrationType();
RegNode = Builder.CreateAlloca(RegNodeTy);
- // FIXME: We can skip this in -GS- mode, when we figure that out.
// SavedESP = llvm.stacksave()
Value *SP = Builder.CreateCall(
Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {});
FunctionType *TargetFuncTy =
FunctionType::get(Int32Ty, makeArrayRef(&ArgTys[0], 5),
/*isVarArg=*/false);
- Function *Trampoline = Function::Create(
- TrampolineTy, GlobalValue::InternalLinkage,
- Twine("__ehhandler$") + ParentFunc->getName(), TheModule);
+ Function *Trampoline =
+ Function::Create(TrampolineTy, GlobalValue::InternalLinkage,
+ Twine("__ehhandler$") + GlobalValue::getRealLinkageName(
+ ParentFunc->getName()),
+ TheModule);
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", Trampoline);
IRBuilder<> Builder(EntryBB);
Value *LSDA = emitEHLSDA(Builder, ParentFunc);
}
void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder,
- Value *Handler) {
+ 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(LinkTy, Link, 1));
+ Value *HandlerI8 = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
+ Builder.CreateStore(HandlerI8, Builder.CreateStructGEP(LinkTy, Link, 1));
// Next = [fs:00]
Constant *FSZero =
Constant::getNullValue(LinkTy->getPointerTo()->getPointerTo(257));
Builder.CreateStore(Next, FSZero);
}
-void WinEHStatePass::addCXXStateStores(Function &F, MachineModuleInfo &MMI) {
- WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(&F);
+void WinEHStatePass::addCXXStateStores(Function &F, WinEHFuncInfo &FuncInfo) {
calculateWinCXXEHStateNumbers(&F, FuncInfo);
// The base state for the parent is -1.
- addCXXStateStoresToFunclet(RegNode, FuncInfo, F, -1);
+ addStateStoresToFunclet(RegNode, FuncInfo, F, -1);
// Set up RegNodeEscapeIndex
int RegNodeEscapeIndex = escapeRegNode(F);
-
- // Only insert stores in catch handlers.
- Function *FrameRecover =
- Intrinsic::getDeclaration(TheModule, Intrinsic::framerecover);
- Function *FrameAddress =
- Intrinsic::getDeclaration(TheModule, Intrinsic::frameaddress);
- 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);
- }
+ FuncInfo.EHRegNodeEscapeIndex = RegNodeEscapeIndex;
}
/// 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
+/// to localescape, 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.
+ // Find the call to localescape and extract its arguments.
IntrinsicInst *EscapeCall = nullptr;
for (Instruction &I : F.getEntryBlock()) {
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
- if (II && II->getIntrinsicID() == Intrinsic::frameescape) {
+ if (II && II->getIntrinsicID() == Intrinsic::localescape) {
EscapeCall = II;
break;
}
// 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(
- Intrinsic::getDeclaration(TheModule, Intrinsic::frameescape), Args);
+ Instruction *InsertPt = EscapeCall;
+ if (!EscapeCall)
+ InsertPt = F.getEntryBlock().getTerminator();
+ IRBuilder<> Builder(&F.getEntryBlock(), InsertPt);
+ Builder.CreateCall(FrameEscape, Args);
if (EscapeCall)
EscapeCall->eraseFromParent();
return Args.size() - 1;
}
-void WinEHStatePass::addCXXStateStoresToFunclet(Value *ParentRegNode,
- WinEHFuncInfo &FuncInfo,
- Function &F, int BaseState) {
+void WinEHStatePass::insertRestoreFrame(BasicBlock *BB) {
+ Instruction *Start = BB->getFirstInsertionPt();
+ if (match(Start, m_Intrinsic<Intrinsic::x86_seh_restoreframe>()))
+ return;
+ IRBuilder<> Builder(Start);
+ Builder.CreateCall(RestoreFrame, {});
+}
+
+void WinEHStatePass::addStateStoresToFunclet(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) {
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();
+ Instruction *PadInst = II->getUnwindDest()->getFirstNonPHI();
// FIXME: Why does this assertion fail?
- //assert(FuncInfo.LandingPadStateMap.count(LPI) && "LP has no state!");
- int State = FuncInfo.LandingPadStateMap[LPI];
+ //assert(FuncInfo.EHPadStateMap.count(PadInst) && "EH Pad has no state!");
+ int State = FuncInfo.EHPadStateMap[PadInst];
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, WinEHFuncInfo &FuncInfo) {
+ // Remember and return the index that we used. We save it in WinEHFuncInfo so
+ // that we can lower llvm.x86.seh.recoverfp later in filter functions without
+ // too much trouble.
+ int RegNodeEscapeIndex = escapeRegNode(F);
+ FuncInfo.EHRegNodeEscapeIndex = RegNodeEscapeIndex;
+
+ // If this funciton uses the new EH IR, use the explicit state numbering
+ // algorithm and return early.
+ bool UsesLPads = false;
+ for (BasicBlock &BB : F) {
+ if (BB.isLandingPad()) {
+ UsesLPads = true;
+ break;
+ }
+ }
+ if (!UsesLPads) {
+ calculateSEHStateNumbers(&F, FuncInfo);
+ addStateStoresToFunclet(RegNode, FuncInfo, F, -1);
+ return;
+ }
+ // FIXME: Delete the rest of this code and clean things up when new EH is
+ // done.
+
+ // 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.EHPadStateMap.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());
+#ifndef NDEBUG
+ for (BasicBlock *Pred : predecessors(BA->getBasicBlock()))
+ assert(Pred->isLandingPad() &&
+ "WinEHPrepare failed to split block");
+#endif
+ ExceptBlocks.insert(BA->getBasicBlock());
+ }
+ }
+ }
+ insertStateNumberStore(RegNode, II, State);
+ }
+ }
+ }
+
+ // Insert llvm.x86.seh.restoreframe() into each __except block.
+ Function *RestoreFrame =
+ Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_restoreframe);
+ for (BasicBlock *ExceptBB : ExceptBlocks) {
+ IRBuilder<> Builder(ExceptBB->begin());
+ Builder.CreateCall(RestoreFrame, {});
+ }
+}
+
void WinEHStatePass::insertStateNumberStore(Value *ParentRegNode,
Instruction *IP, int State) {
IRBuilder<> Builder(IP);
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