[WinEH] Start inserting state number stores for C++ EH
This moves all the state numbering code for C++ EH to WinEHPrepare so
that we can call it from the X86 state numbering IR pass that runs
before isel.
Now we just call the same state numbering machinery and insert a bunch
of stores. It also populates MachineModuleInfo with information about
the current function.
llvm-svn: 238514
diff --git a/llvm/lib/Target/X86/X86WinEHState.cpp b/llvm/lib/Target/X86/X86WinEHState.cpp
index 4efaada..1a205e8 100644
--- a/llvm/lib/Target/X86/X86WinEHState.cpp
+++ b/llvm/lib/Target/X86/X86WinEHState.cpp
@@ -16,6 +16,7 @@
#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"
@@ -59,14 +60,19 @@
private:
void emitExceptionRegistrationRecord(Function *F);
- void linkExceptionRegistration(IRBuilder<> &Builder, Value *RegNode,
- Value *Handler);
- void unlinkExceptionRegistration(IRBuilder<> &Builder, Value *RegNode);
+ void linkExceptionRegistration(IRBuilder<> &Builder, Value *Handler);
+ void unlinkExceptionRegistration(IRBuilder<> &Builder);
+ void addCXXStateStores(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();
@@ -83,6 +89,19 @@
// 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;
};
}
@@ -137,7 +156,13 @@
return false;
emitExceptionRegistrationRecord(&F);
- // FIXME: State insertion.
+
+ auto *MMIPtr = getAnalysisIfAvailable<MachineModuleInfo>();
+ assert(MMIPtr && "MachineModuleInfo should always be available");
+ MachineModuleInfo &MMI = *MMIPtr;
+ if (Personality == EHPersonality::MSVC_CXX) {
+ addCXXStateStores(F, MMI);
+ }
// Reset per-function state.
PersonalityFn = nullptr;
@@ -238,62 +263,61 @@
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);
+ RegNodeTy = getCXXEH3RegistrationType();
+ 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), {});
Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
// TryLevel = -1
- Builder.CreateStore(Builder.getInt32(-1),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 2));
+ StateFieldIndex = 2;
+ insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1);
// Handler = __ehhandler$F
Function *Trampoline = generateLSDAInEAXThunk(F);
- SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
- linkExceptionRegistration(Builder, SubRecord, Trampoline);
+ Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
+ linkExceptionRegistration(Builder, Trampoline);
} else if (PersonalityName == "_except_handler3") {
- Type *RegNodeTy = getSEH3RegistrationType();
- Value *RegNode = Builder.CreateAlloca(RegNodeTy);
+ RegNodeTy = getSEH3RegistrationType();
+ RegNode = Builder.CreateAlloca(RegNodeTy);
// TryLevel = -1
- Builder.CreateStore(Builder.getInt32(-1),
- Builder.CreateStructGEP(RegNodeTy, RegNode, 2));
+ StateFieldIndex = 2;
+ insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1);
// ScopeTable = llvm.x86.seh.lsda(F)
Value *LSDA = emitEHLSDA(Builder, F);
Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
- SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 0);
- linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
+ Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 0);
+ linkExceptionRegistration(Builder, PersonalityFn);
} else if (PersonalityName == "_except_handler4") {
- Type *RegNodeTy = getSEH4RegistrationType();
- Value *RegNode = Builder.CreateAlloca(RegNodeTy);
+ RegNodeTy = getSEH4RegistrationType();
+ 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));
+ // TryLevel = -1
+ StateFieldIndex = 4;
+ insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1);
// FIXME: XOR the LSDA with __security_cookie.
// ScopeTable = llvm.x86.seh.lsda(F)
Value *FI8 = Builder.CreateBitCast(F, Int8PtrType);
Value *LSDA = Builder.CreateCall(
Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_lsda), FI8);
Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
- SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 2);
- linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
+ 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);
}
}
@@ -342,33 +366,127 @@
}
void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder,
- Value *RegNode, Value *Handler) {
- Type *RegNodeTy = getEHRegistrationType();
+ Value *Handler) {
+ Type *LinkTy = getEHRegistrationType();
// Handler = Handler
Handler = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
- Builder.CreateStore(Handler, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
+ Builder.CreateStore(Handler, 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 = getEHRegistrationType();
+ // [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.
+ 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);
+ }
+}
+
+/// 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(
+ Intrinsic::getDeclaration(TheModule, Intrinsic::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);
+ }
+ }
+ }
+}
+
+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);
+}