vendor/llvm/llvm-trunk-r240225

1 files changed, 83 insertions, 16 deletions

diff --git a/lib/Target/X86/X86WinEHState.cpp b/lib/Target/X86/X86WinEHState.cpp
index ce69ea721993..c9e80945549b 100644
--- a/lib/Target/X86/X86WinEHState.cpp
+++ b/lib/Target/X86/X86WinEHState.cpp
@@ -60,9 +60,10 @@ public:
 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 addSEHStateStores(Function &F, MachineModuleInfo &MMI);
   void addCXXStateStoresToFunclet(Value *ParentRegNode, WinEHFuncInfo &FuncInfo,
                                   Function &F, int BaseState);
   void insertStateNumberStore(Value *ParentRegNode, Instruction *IP, int State);
@@ -104,7 +105,7 @@ private:
   /// The linked list node subobject inside of RegNode.
   Value *Link = nullptr;
 };
-}
+} // namespace
 
 FunctionPass *llvm::createX86WinEHStatePass() { return new WinEHStatePass(); }
 
@@ -145,16 +146,10 @@ bool WinEHStatePass::runOnFunction(Function &F) {
     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);
@@ -171,8 +166,10 @@ bool WinEHStatePass::runOnFunction(Function &F) {
   auto *MMIPtr = getAnalysisIfAvailable<MachineModuleInfo>();
   assert(MMIPtr && "MachineModuleInfo should always be available");
   MachineModuleInfo &MMI = *MMIPtr;
-  if (Personality == EHPersonality::MSVC_CXX) {
-    addCXXStateStores(F, MMI);
+  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.
@@ -258,7 +255,6 @@ void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) {
   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), {});
@@ -360,11 +356,14 @@ Function *WinEHStatePass::generateLSDAInEAXThunk(Function *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));
@@ -472,6 +471,74 @@ void WinEHStatePass::addCXXStateStoresToFunclet(Value *ParentRegNode,
   }
 }
 
+/// 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);