[WebAssembly] Fix bugs in WebAssemblyLowerEmscriptenExceptions pass

[aheejin]

Summary

This patch fixes several bugs in WebAssemblyLowerEmscriptenExceptions pass. Depends on D22958.

1. Delete '_' prefixes from JS library function names. fixImports() function in JS glue code deals with this for wasm.
2. Change command-line option names in order to be consistent with asm.js.
3. Add missing lowering code for llvm.eh.typeid.for intrinsics
4. Delete commas in mangled function names
5. Fix a function argument attributes bug. Because we add the pointer to the original callee as the first argument of invoke wrapper, all argument attribute indices have to be incremented by one.

[aheejin]

Add a test case for -emscripten-cxx-exceptions-whitelist option & Fix a bug

[dschuff]

Can we split the bugfixes into a separate CL from the cxx-exceptions-whitelist option (which is new functionality)?

[aheejin]

Removed the cxx-exceptions-whitelist option from this CL

[aheejin]

Remove the test case for cxx-exceptions-whitelist option

[dschuff]

lib/Target/WebAssembly/WebAssemblyLowerEmscriptenExceptions.cpp

339

We could just have
LLVMContext &C = F.getContext();
Then this and all those getContext() calls below would be shorter.

424

This seems subtle. Why does setAttributes have to go after setDebugLoc?

[aheejin]

Address comments

[dschuff]

LGTM

[aheejin]

lib/Target/WebAssembly/WebAssemblyLowerEmscriptenExceptions.cpp

424

In the 'invoke' case above, I changed the order of setAttributes and setDebugLoc because setAttribute part got longer so I thought it would look tidier. The reason I changed the order in this 'call' part is just to be consistent with the 'invoke' part. Does the order matter?

[dschuff]

lib/Target/WebAssembly/WebAssemblyLowerEmscriptenExceptions.cpp

424

No, it actually doesn't; doing it just for consistency is fine, I just wanted to make sure there wasn't some subtle issue I was missing.

lib/Target/WebAssembly/WebAssemblyLowerEmscriptenExceptions.cpp

 /// (Location: https://github.com/kripken/emscripten-fastcomp)
 /// lib/Target/JSBackend/NaCl/LowerEmExceptionsPass.cpp
 /// lib/Target/JSBackend/JSBackend.cpp
 /// lib/Target/JSBackend/CallHandlers.h
 ///
 /// This pass does following things:
 ///
 /// 1) Create three global variables: __THREW__, threwValue, and tempRet0.
-///    tempRet0 will be set within ___cxa_find_matching_catch() function in
+///    tempRet0 will be set within __cxa_find_matching_catch() function in
 ///    JS library, and __THREW__ and threwValue will be set in invoke wrappers
 ///    in JS glue code. For what invoke wrappers are, refer to 3).
 ///
 /// 2) Create setThrew and setTempRet0 functions.
 ///    The global variables created in 1) will exist in wasm address space,
 ///    but their values should be set in JS code, so we provide these functions
 ///    as interfaces to JS glue code. These functions are equivalent to the
 ///    following JS functions, which actually exist in asm.js version of JS

 ///      }
 ///    If an exception is thrown, __THREW__ will be set to true in a wrapper,
 ///    so we can jump to the right BB based on this value.
 ///
 /// 4) Lower
 ///      %val = landingpad catch c1 catch c2 catch c3 ...
 ///      ... use %val ...
 ///    into
-///      %fmc = call @___cxa_find_matching_catch_N(c1, c2, c3, ...)
+///      %fmc = call @__cxa_find_matching_catch_N(c1, c2, c3, ...)
 ///      %val = {%fmc, tempRet0}
 ///      ... use %val ...
 ///    Here N is a number calculated based on the number of clauses.
-///    Global variable tempRet0 is set within ___cxa_find_matching_catch() in
+///    Global variable tempRet0 is set within __cxa_find_matching_catch() in
 ///    JS glue code.
 ///
 /// 5) Lower
 ///      resume {%a, %b}
 ///    into
-///      call @___resumeException(%a)
-///    where ___resumeException() is a function in JS glue code.
+///      call @__resumeException(%a)
+///    where __resumeException() is a function in JS glue code.
 ///
-/// TODO: Handle i64 types
+/// 6) Lower
+///      call @llvm.eh.typeid.for(type) (intrinsic)
+///    into
+///      call @llvm_eh_typeid_for(type)
+///    llvm_eh_typeid_for function will be generated in JS glue code.
 ///
 ///===----------------------------------------------------------------------===//
 
 #include "WebAssembly.h"
-#include "llvm/ADT/IndexedMap.h"
-#include "llvm/IR/Constants.h"
+#include "llvm/IR/CallSite.h"
 #include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/Instructions.h"
 #include "llvm/IR/Module.h"
-#include "llvm/Pass.h"
 #include "llvm/Support/raw_ostream.h"
+#include <set>
 
 using namespace llvm;
 
 #define DEBUG_TYPE "wasm-lower-em-exceptions"
 
+static cl::list<std::string>
+    Whitelist("emscripten-cxx-exceptions-whitelist",
+              cl::desc("The list of function names in which Emscripten-style "
+                       "exception handling is enabled (see emscripten "
+                       "EMSCRIPTEN_CATCHING_WHITELIST options)"),
+              cl::CommaSeparated);
+
 namespace {
 class WebAssemblyLowerEmscriptenExceptions final : public ModulePass {
   const char *getPassName() const override {
     return "WebAssembly Lower Emscripten Exceptions";
   }
 
   bool runOnFunction(Function &F);
-  // Returns ___cxa_find_matching_catch_N function, where N = NumClauses + 2.
+  // Returns __cxa_find_matching_catch_N function, where N = NumClauses + 2.
   // This is because a landingpad instruction contains two more arguments,
-  // a personality function and a cleanup bit, and ___cxa_find_matching_catch_N
+  // a personality function and a cleanup bit, and __cxa_find_matching_catch_N
   // functions are named after the number of arguments in the original
   // landingpad instruction.
   Function *getFindMatchingCatch(Module &M, unsigned NumClauses);
 
   Function *getInvokeWrapper(Module &M, InvokeInst *II);
 
   GlobalVariable *ThrewGV;      // __THREW__
   GlobalVariable *ThrewValueGV; // threwValue
   GlobalVariable *TempRet0GV;   // tempRet0
-  Function *ResumeF;
-  // ___cxa_find_matching_catch_N functions.
+  Function *ResumeF;            // __resumeException
+  Function *EHTypeIdF;          // llvm_eh_typeid_for
+  // __cxa_find_matching_catch_N functions.
   // Indexed by the number of clauses in an original landingpad instruction.
   DenseMap<int, Function *> FindMatchingCatches;
   // Map of <function signature string, invoke_ wrappers>
   StringMap<Function *> InvokeWrappers;
 
 public:
   static char ID;
 
static inline std::string createGlobalValueName(const Module &M,
   std::string Name = Propose;
   while (M.getNamedGlobal(Name))
     Name += "_";
   return Name;
 }
 
 // Simple function name mangler.
 // This function simply takes LLVM's string representation of parameter types
-// concatenate them with '_'. There are non-alphanumeric characters but llc is
-// ok with it, and we need to postprocess these names after the lowering phase
-// anyway.
+// and concatenate them with '_'. There are non-alphanumeric characters but llc
+// is ok with it, and we need to postprocess these names after the lowering
+// phase anyway.
 static std::string getSignature(FunctionType *FTy) {
   std::string Sig;
   raw_string_ostream OS(Sig);
   OS << *FTy->getReturnType();
   for (Type *ParamTy : FTy->params())
     OS << "_" << *ParamTy;
   if (FTy->isVarArg())
     OS << "_...";
   Sig = OS.str();
   Sig.erase(std::remove_if(Sig.begin(), Sig.end(), isspace), Sig.end());
+  // When s2wasm parses .s file, a comma means the end of an argument. So a
+  // mangled function name can contain any character but a comma.
+  std::replace(Sig.begin(), Sig.end(), ',', '.');
   return Sig;
 }
 
 Function *WebAssemblyLowerEmscriptenExceptions::getFindMatchingCatch(
     Module &M, unsigned NumClauses) {
   if (FindMatchingCatches.count(NumClauses))
     return FindMatchingCatches[NumClauses];
   PointerType *Int8PtrTy = Type::getInt8PtrTy(M.getContext());
   SmallVector<Type *, 16> Args(NumClauses, Int8PtrTy);
   FunctionType *FTy = FunctionType::get(Int8PtrTy, Args, false);
   Function *F = Function::Create(
       FTy, GlobalValue::ExternalLinkage,
-      "___cxa_find_matching_catch_" + Twine(NumClauses + 2), &M);
+      "__cxa_find_matching_catch_" + Twine(NumClauses + 2), &M);
   FindMatchingCatches[NumClauses] = F;
   return F;
 }
 
 Function *
 WebAssemblyLowerEmscriptenExceptions::getInvokeWrapper(Module &M,
                                                        InvokeInst *II) {
   SmallVector<Type *, 16> ArgTys;
WebAssemblyLowerEmscriptenExceptions::getInvokeWrapper(Module &M,
   return F;
 }
 
 bool WebAssemblyLowerEmscriptenExceptions::runOnModule(Module &M) {
   IRBuilder<> Builder(M.getContext());
   IntegerType *Int1Ty = Builder.getInt1Ty();
   PointerType *Int8PtrTy = Builder.getInt8PtrTy();
   IntegerType *Int32Ty = Builder.getInt32Ty();
+  Type *VoidTy = Builder.getVoidTy();
 
   // Create global variables __THREW__, threwValue, and tempRet0
   ThrewGV = new GlobalVariable(M, Int1Ty, false, GlobalValue::ExternalLinkage,
                                Builder.getFalse(),
                                createGlobalValueName(M, "__THREW__"));
   ThrewValueGV = new GlobalVariable(
       M, Int32Ty, false, GlobalValue::ExternalLinkage, Builder.getInt32(0),
       createGlobalValueName(M, "threwValue"));
   TempRet0GV = new GlobalVariable(
       M, Int32Ty, false, GlobalValue::ExternalLinkage, Builder.getInt32(0),
       createGlobalValueName(M, "tempRet0"));
 
-  // Register ___resumeException function
-  Type *VoidTy = Type::getVoidTy(M.getContext());
+  // Register __resumeException function
   FunctionType *ResumeFTy = FunctionType::get(VoidTy, Int8PtrTy, false);
   ResumeF = Function::Create(ResumeFTy, GlobalValue::ExternalLinkage,
-                             "___resumeException", &M);
+                             "__resumeException", &M);
+
+  // Register llvm_eh_typeid_for function
+  FunctionType *EHTypeIdTy = FunctionType::get(Int32Ty, Int8PtrTy, false);
+  EHTypeIdF = Function::Create(EHTypeIdTy, GlobalValue::ExternalLinkage,
+                               "llvm_eh_typeid_for", &M);
+
+  std::set<std::string> WhitelistSet(Whitelist.begin(), Whitelist.end());
 
   bool Changed = false;
   for (Function &F : M) {
     if (F.isDeclaration())
       continue;
+    if (WhitelistSet.empty() || WhitelistSet.count(F.getName()))
       Changed |= runOnFunction(F);
   }
 
   if (!Changed)
     return false;
 
   assert(!M.getNamedGlobal("setThrew") && "setThrew already exists");
   assert(!M.getNamedGlobal("setTempRet0") && "setTempRet0 already exists");
 
bool WebAssemblyLowerEmscriptenExceptions::runOnModule(Module &M) {
   Builder.CreateStore(&*F->arg_begin(), TempRet0GV);
   Builder.CreateRetVoid();
 
   return true;
 }
 
 bool WebAssemblyLowerEmscriptenExceptions::runOnFunction(Function &F) {
   Module &M = *F.getParent();
-  IRBuilder<> Builder(M.getContext());
+  IRBuilder<> Builder(F.getContext());
   bool Changed = false;
   SmallVector<Instruction *, 64> ToErase;
   SmallPtrSet<LandingPadInst *, 32> LandingPads;
 
   for (BasicBlock &BB : F) {
     auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
     if (!II)
       continue;
     Changed = true;
     LandingPads.insert(II->getLandingPadInst());
     Builder.SetInsertPoint(II);
 
     if (canThrow(II->getCalledValue())) {
       // If we are calling a function that is noreturn, we must remove that
       // attribute. The code we insert here does expect it to return, after we
       // catch the exception.
       if (II->doesNotReturn()) {
         if (auto *F = dyn_cast<Function>(II->getCalledValue()))
           F->removeFnAttr(Attribute::NoReturn);
         AttributeSet NewAttrs = II->getAttributes();
-        NewAttrs.removeAttribute(M.getContext(), AttributeSet::FunctionIndex,
+        NewAttrs.removeAttribute(F.getContext(), AttributeSet::FunctionIndex,
                                  Attribute::NoReturn);
         II->setAttributes(NewAttrs);
       }
 
       // Pre-invoke
       // __THREW__ = 0;
       Builder.CreateStore(Builder.getFalse(), ThrewGV);
 
       // Invoke function wrapper in JavaScript
       SmallVector<Value *, 16> CallArgs;
       // Put the pointer to the callee as first argument, so it can be called
       // within the invoke wrapper later
       CallArgs.push_back(II->getCalledValue());
       CallArgs.append(II->arg_begin(), II->arg_end());
       CallInst *NewCall = Builder.CreateCall(getInvokeWrapper(M, II), CallArgs);
       NewCall->takeName(II);
       NewCall->setCallingConv(II->getCallingConv());
-      NewCall->setAttributes(II->getAttributes());
       NewCall->setDebugLoc(II->getDebugLoc());
+
+      // Because we added the pointer to the callee as first argument, all
+      // argument attribute indices have to be incremented by one.
+      SmallVector<AttributeSet, 8> AttributesVec;
+      const AttributeSet &InvokePAL = II->getAttributes();
+      CallSite::arg_iterator AI = II->arg_begin();
+      unsigned i = 1; // Argument attribute index starts from 1
+      for (unsigned e = II->getNumArgOperands(); i <= e; ++AI, ++i) {
+        if (InvokePAL.hasAttributes(i)) {
+          AttrBuilder B(InvokePAL, i);
+          AttributesVec.push_back(AttributeSet::get(F.getContext(), i + 1, B));
+        }
+      }
+      // Add any return attributes.
+      if (InvokePAL.hasAttributes(AttributeSet::ReturnIndex))
+        AttributesVec.push_back(
+            AttributeSet::get(II->getContext(), InvokePAL.getRetAttributes()));
+      // Add any function attributes.
+      if (InvokePAL.hasAttributes(AttributeSet::FunctionIndex))
+        AttributesVec.push_back(
+            AttributeSet::get(II->getContext(), InvokePAL.getFnAttributes()));
+      // Reconstruct the AttributesList based on the vector we constructed.
+      AttributeSet NewCallPAL =
+          AttributeSet::get(F.getContext(), AttributesVec);
+      NewCall->setAttributes(NewCallPAL);
+
       II->replaceAllUsesWith(NewCall);
       ToErase.push_back(II);
 
       // Post-invoke
       // %__THREW__.val = __THREW__; __THREW__ = 0;
       Value *Threw = Builder.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
       Builder.CreateStore(Builder.getFalse(), ThrewGV);
 
       // Insert a branch based on __THREW__ variable
       Builder.CreateCondBr(Threw, II->getUnwindDest(), II->getNormalDest());
 
     } else {
       // This can't throw, and we don't need this invoke, just replace it with a
       // call+branch
       SmallVector<Value *, 16> CallArgs(II->arg_begin(), II->arg_end());
       CallInst *NewCall = Builder.CreateCall(II->getCalledValue(), CallArgs);
       NewCall->takeName(II);
       NewCall->setCallingConv(II->getCallingConv());
-      NewCall->setAttributes(II->getAttributes());
       NewCall->setDebugLoc(II->getDebugLoc());
+      NewCall->setAttributes(II->getAttributes());
       II->replaceAllUsesWith(NewCall);
       ToErase.push_back(II);
 
       Builder.CreateBr(II->getNormalDest());
 
       // Remove any PHI node entries from the exception destination
       II->getUnwindDest()->removePredecessor(&BB);
     }
   }
 
   // Process resume instructions
   for (BasicBlock &BB : F) {
     // Scan the body of the basic block for resumes
     for (Instruction &I : BB) {
       auto *RI = dyn_cast<ResumeInst>(&I);
       if (!RI)
         continue;
 
       // Split the input into legal values
       Value *Input = RI->getValue();
       Builder.SetInsertPoint(RI);
       Value *Low = Builder.CreateExtractValue(Input, 0, "low");
 
-      // Create a call to ___resumeException function
+      // Create a call to __resumeException function
       Value *Args[] = {Low};
       Builder.CreateCall(ResumeF, Args);
 
       // Add a terminator to the block
       Builder.CreateUnreachable();
       ToErase.push_back(RI);
     }
   }
 
+  // Process llvm.eh.typeid.for intrinsics
+  for (BasicBlock &BB : F) {
+    for (Instruction &I : BB) {
+      auto *CI = dyn_cast<CallInst>(&I);
+      if (!CI)
+        continue;
+      const Function *Callee = CI->getCalledFunction();
+      if (!Callee)
+        continue;
+      if (Callee->getIntrinsicID() != Intrinsic::eh_typeid_for)
+        continue;
+
+      Builder.SetInsertPoint(CI);
+      CallInst *NewCI =
+          Builder.CreateCall(EHTypeIdF, CI->getArgOperand(0), "typeid");
+      CI->replaceAllUsesWith(NewCI);
+      ToErase.push_back(CI);
+    }
+  }
+
   // Look for orphan landingpads, can occur in blocks with no predecesors
   for (BasicBlock &BB : F) {
     Instruction *I = BB.getFirstNonPHI();
     if (auto *LPI = dyn_cast<LandingPadInst>(I))
       LandingPads.insert(LPI);
   }
 
   // Handle all the landingpad for this function together, as multiple invokes
for (unsigned i = 0, e = LPI->getNumClauses(); i < e; ++i) {
           Value *EV =
               Builder.CreateExtractValue(Clause, makeArrayRef(j), "filter");
           FMCArgs.push_back(EV);
         }
       } else
         FMCArgs.push_back(Clause);
     }
 
-    // Create a call to ___cxa_find_matching_catch_N function
+    // Create a call to __cxa_find_matching_catch_N function
     Function *FMCF = getFindMatchingCatch(M, FMCArgs.size());
     CallInst *FMCI = Builder.CreateCall(FMCF, FMCArgs, "fmc");
     Value *Undef = UndefValue::get(LPI->getType());
     Value *Pair0 = Builder.CreateInsertValue(Undef, FMCI, 0, "pair0");
     Value *TempRet0 =
         Builder.CreateLoad(TempRet0GV, TempRet0GV->getName() + "val");
     Value *Pair1 = Builder.CreateInsertValue(Pair0, TempRet0, 1, "pair1");
 

lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp

 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Transforms/Scalar.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "wasm"
 
 // Emscripten's asm.js-style exception handling
 static cl::opt<bool> EnableEmExceptionHandling(
-    "wasm-em-exception-handling",
+    "enable-emscripten-cxx-exceptions",
     cl::desc("WebAssembly Emscripten-style exception handling"),
     cl::init(false));
 
 extern "C" void LLVMInitializeWebAssemblyTarget() {
   // Register the target.
   RegisterTargetMachine<WebAssemblyTargetMachine> X(TheWebAssemblyTarget32);
   RegisterTargetMachine<WebAssemblyTargetMachine> Y(TheWebAssemblyTarget64);
 

test/CodeGen/WebAssembly/lower-em-exceptions.ll

 lpad:                                             ; preds = %entry
   %0 = landingpad { i8*, i32 }
           catch i8* bitcast (i8** @_ZTIi to i8*)
           catch i8* null
   %1 = extractvalue { i8*, i32 } %0, 0
   %2 = extractvalue { i8*, i32 } %0, 1
   br label %catch.dispatch
 ; CHECK: lpad:
-; CHECK-NEXT: %[[FMC:.*]] = call i8* @___cxa_find_matching_catch_4(i8* bitcast (i8** @_ZTIi to i8*), i8* null)
+; CHECK-NEXT: %[[FMC:.*]] = call i8* @__cxa_find_matching_catch_4(i8* bitcast (i8** @_ZTIi to i8*), i8* null)
 ; CHECK-NEXT: %[[IVI1:.*]] = insertvalue { i8*, i32 } undef, i8* %[[FMC]], 0
 ; CHECK-NEXT: %[[TEMPRET0_VAL:.*]] = load i32, i32* @[[TEMPRET0]]
 ; CHECK-NEXT: %[[IVI2:.*]] = insertvalue { i8*, i32 } %[[IVI1]], i32 %[[TEMPRET0_VAL]], 1
 ; CHECK-NEXT: extractvalue { i8*, i32 } %[[IVI2]], 0
 ; CHECK-NEXT: extractvalue { i8*, i32 } %[[IVI2]], 1
 
 catch.dispatch:                                   ; preds = %lpad
   %3 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))

 
 lpad:                                             ; preds = %entry
   %0 = landingpad { i8*, i32 }
           filter [2 x i8*] [i8* bitcast (i8** @_ZTIi to i8*), i8* bitcast (i8** @_ZTIc to i8*)]
   %1 = extractvalue { i8*, i32 } %0, 0
   %2 = extractvalue { i8*, i32 } %0, 1
   br label %filter.dispatch
 ; CHECK: lpad:
-; CHECK-NEXT: %[[FMC:.*]] = call i8* @___cxa_find_matching_catch_4(i8* bitcast (i8** @_ZTIi to i8*), i8* bitcast (i8** @_ZTIc to i8*))
+; CHECK-NEXT: %[[FMC:.*]] = call i8* @__cxa_find_matching_catch_4(i8* bitcast (i8** @_ZTIi to i8*), i8* bitcast (i8** @_ZTIc to i8*))
 ; CHECK-NEXT: %[[IVI1:.*]] = insertvalue { i8*, i32 } undef, i8* %[[FMC]], 0
 ; CHECK-NEXT: %[[TEMPRET0_VAL:.*]] = load i32, i32* @[[TEMPRET0]]
 ; CHECK-NEXT: %[[IVI2:.*]] = insertvalue { i8*, i32 } %[[IVI1]], i32 %[[TEMPRET0_VAL]], 1
 ; CHECK-NEXT: extractvalue { i8*, i32 } %[[IVI2]], 0
 ; CHECK-NEXT: extractvalue { i8*, i32 } %[[IVI2]], 1
 
 filter.dispatch:                                  ; preds = %lpad
   %ehspec.fails = icmp slt i32 %2, 0
   br i1 %ehspec.fails, label %ehspec.unexpected, label %eh.resume
 
 ehspec.unexpected:                                ; preds = %filter.dispatch
   call void @__cxa_call_unexpected(i8* %1) #4
   unreachable
 
 eh.resume:                                        ; preds = %filter.dispatch
   %lpad.val = insertvalue { i8*, i32 } undef, i8* %1, 0
   %lpad.val3 = insertvalue { i8*, i32 } %lpad.val, i32 %2, 1
   resume { i8*, i32 } %lpad.val3
 ; CHECK: eh.resume:
 ; CHECK-NEXT: insertvalue
 ; CHECK-NEXT: %[[LPAD_VAL:.*]] = insertvalue
 ; CHECK-NEXT: %[[LOW:.*]] = extractvalue { i8*, i32 } %[[LPAD_VAL]], 0
-; CHECK-NEXT: call void @___resumeException(i8* %[[LOW]])
+; CHECK-NEXT: call void @__resumeException(i8* %[[LOW]])
 ; CHECK-NEXT: unreachable
 }
 
+; Test if argument attributes indices in newly created call instructions are correct
+define void @arg_attributes() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; CHECK-LABEL: @arg_attributes(
+entry:
+  %0 = invoke noalias i8* @bar(i8 signext 1, i8 zeroext 2)
+          to label %invoke.cont unwind label %lpad
+; CHECK: entry:
+; CHECK-NEXT: store i1 false, i1* @[[__THREW__]]
+; CHECK-NEXT: %0 = call noalias i8* @"__invoke_i8*_i8_i8"(i8* (i8, i8)* @bar, i8 signext 1, i8 zeroext 2)
+
+invoke.cont:                                      ; preds = %entry
+  br label %try.cont
+
+lpad:                                             ; preds = %entry
+  %1 = landingpad { i8*, i32 }
+          catch i8* bitcast (i8** @_ZTIi to i8*)
+          catch i8* null
+  %2 = extractvalue { i8*, i32 } %1, 0
+  %3 = extractvalue { i8*, i32 } %1, 1
+  br label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %lpad
+  %4 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches = icmp eq i32 %3, %4
+  br i1 %matches, label %catch1, label %catch
+
+catch1:                                           ; preds = %catch.dispatch
+  %5 = call i8* @__cxa_begin_catch(i8* %2)
+  %6 = bitcast i8* %5 to i32*
+  %7 = load i32, i32* %6, align 4
+  call void @__cxa_end_catch()
+  br label %try.cont
+
+try.cont:                                         ; preds = %catch, %catch1, %invoke.cont
+  ret void
+
+catch:                                            ; preds = %catch.dispatch
+  %8 = call i8* @__cxa_begin_catch(i8* %2)
+  call void @__cxa_end_catch()
+  br label %try.cont
+}
+
 declare void @foo(i32)
+declare i8* @bar(i8, i8)
 
 declare i32 @__gxx_personality_v0(...)
 declare i32 @llvm.eh.typeid.for(i8*)
 declare i8* @__cxa_begin_catch(i8*)
 declare void @__cxa_end_catch()
 declare void @__cxa_call_unexpected(i8*)
 
 ; JS glue functions and invoke wrappers registration
-; CHECK: declare void @___resumeException(i8*)
+; CHECK: declare void @__resumeException(i8*)
 ; CHECK: declare void @__invoke_void_i32(void (i32)*, i32)
-; CHECK: declare i8* @___cxa_find_matching_catch_4(i8*, i8*)
+; CHECK: declare i8* @__cxa_find_matching_catch_4(i8*, i8*)
 
 ; setThrew function creation
 ; CHECK-LABEL: define void @setThrew(i1 %threw, i32 %value) {
 ; CHECK: entry:
 ; CHECK-NEXT: %__THREW__.val = load i1, i1* @__THREW__
 ; CHECK-NEXT: %cmp = icmp eq i1 %__THREW__.val, false
 ; CHECK-NEXT: br i1 %cmp, label %if.then, label %if.end
 ; CHECK: if.then: