[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

1 files changed, 160 insertions, 42 deletions

diff --git a/llvm/lib/Target/X86/X86WinEHState.cpp b/llvm/lib/Target/X86/X86WinEHState.cpp
index 4efaada4092..1a205e8aec4 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 @@ public:
 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 @@ private:
   // 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 @@ bool WinEHStatePass::runOnFunction(Function &F) {
     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 @@ void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) {
   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 @@ Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) {
 }
 
 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);
+}