[llvm] c285a11 - [WebAssembly] Make Emscripten EH work with Emscripten SjLj

Heejin Ahn via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 26 13:50:28 PDT 2021


Author: Heejin Ahn
Date: 2021-07-26T13:48:31-07:00
New Revision: c285a11efdb0821e6be9fcef695097890f44aa03

URL: https://github.com/llvm/llvm-project/commit/c285a11efdb0821e6be9fcef695097890f44aa03
DIFF: https://github.com/llvm/llvm-project/commit/c285a11efdb0821e6be9fcef695097890f44aa03.diff

LOG: [WebAssembly] Make Emscripten EH work with Emscripten SjLj

When Emscripten EH mixes with Emscripten SjLj, we are not currently
handling some of them correctly. There are three cases:
1. The current function calls `setjmp` and there is an `invoke` to a
   function that can either throw or longjmp. In this case, we have to
   check both for exception and longjmp. We are currently handling this
   case correctly:
   https://github.com/llvm/llvm-project/blob/0c0eb76782d5224b8d81a5afbb9a152bcf7c94c7/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp#L1058-L1090
   When inserting routines for functions that can longjmp, which we do
   only for setjmp-calling functions, we check if the function was
   previously an `invoke` and handle it correctly.

2. The current function does NOT call `setjmp` and there is an `invoke`
   to a function that can either throw or longjmp. Because there is no
   `setjmp` call, we haven't been doing any check for functions that can
   longjmp. But in that case, for `invoke`, we only check for an
   exception and if it is not an exception we reset `__THREW__` to 0,
   which can silently swallow the longjmp:
   https://github.com/llvm/llvm-project/blob/0c0eb76782d5224b8d81a5afbb9a152bcf7c94c7/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp#L70-L80
   This CL fixes this.

3. The current function calls `setjmp` and there is no `invoke`. Because
   it is not an `invoke`, we haven't been doing any check for functions
   that can throw, and only insert longjmp-checking routines for
   functions that can longjmp. But in that case, if a longjmpable
   function throws, we only check for a longjmp so if it is not a
   longjmp we reset `__THREW__` to 0, which can silently swallow the
   exception:
   https://github.com/llvm/llvm-project/blob/0c0eb76782d5224b8d81a5afbb9a152bcf7c94c7/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp#L156-L169
   This CL fixes this.

To do that, this moves around some code, so we register necessary
functions for both EH and SjLj and precompute some data (the set of
functions that contains `setjmp`) before doing actual EH or SjLj
transformation.

This CL makes 2nd and 3rd tests in
https://github.com/emscripten-core/emscripten/pull/14732 work.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D106525

Added: 
    llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj.ll

Modified: 
    llvm/lib/Target/WebAssembly/WebAssembly.h
    llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
    llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/WebAssembly/WebAssembly.h b/llvm/lib/Target/WebAssembly/WebAssembly.h
index 3e9619fba3a3d..9eb960d018d3f 100644
--- a/llvm/lib/Target/WebAssembly/WebAssembly.h
+++ b/llvm/lib/Target/WebAssembly/WebAssembly.h
@@ -25,7 +25,8 @@ class ModulePass;
 class FunctionPass;
 
 // LLVM IR passes.
-ModulePass *createWebAssemblyLowerEmscriptenEHSjLj(bool DoEH, bool DoSjLj);
+ModulePass *createWebAssemblyLowerEmscriptenEHSjLj(bool EnableEH,
+                                                   bool EnableSjLj);
 ModulePass *createWebAssemblyLowerGlobalDtors();
 ModulePass *createWebAssemblyAddMissingPrototypes();
 ModulePass *createWebAssemblyFixFunctionBitcasts();

diff  --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
index fc2d93c3afab7..599829a9e474c 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -216,6 +216,7 @@ namespace {
 class WebAssemblyLowerEmscriptenEHSjLj final : public ModulePass {
   bool EnableEH;   // Enable exception handling
   bool EnableSjLj; // Enable setjmp/longjmp handling
+  bool DoSjLj;     // Whether we actually perform setjmp/longjmp handling
 
   GlobalVariable *ThrewGV = nullptr;
   GlobalVariable *ThrewValueGV = nullptr;
@@ -234,6 +235,8 @@ class WebAssemblyLowerEmscriptenEHSjLj final : public ModulePass {
   StringMap<Function *> InvokeWrappers;
   // Set of allowed function names for exception handling
   std::set<std::string> EHAllowlistSet;
+  // Functions that contains calls to setjmp
+  SmallPtrSet<Function *, 8> SetjmpUsers;
 
   StringRef getPassName() const override {
     return "WebAssembly Lower Emscripten Exceptions";
@@ -252,6 +255,10 @@ class WebAssemblyLowerEmscriptenEHSjLj final : public ModulePass {
   bool areAllExceptionsAllowed() const { return EHAllowlistSet.empty(); }
   bool canLongjmp(Module &M, const Value *Callee) const;
   bool isEmAsmCall(Module &M, const Value *Callee) const;
+  bool supportsException(const Function *F) const {
+    return EnableEH && (areAllExceptionsAllowed() ||
+                        EHAllowlistSet.count(std::string(F->getName())));
+  }
 
   void rebuildSSA(Function &F);
 
@@ -287,7 +294,7 @@ static bool canThrow(const Value *V) {
       return false;
     StringRef Name = F->getName();
     // leave setjmp and longjmp (mostly) alone, we process them properly later
-    if (Name == "setjmp" || Name == "longjmp")
+    if (Name == "setjmp" || Name == "longjmp" || Name == "emscripten_longjmp")
       return false;
     return !F->doesNotThrow();
   }
@@ -693,7 +700,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
   Function *LongjmpF = M.getFunction("longjmp");
   bool SetjmpUsed = SetjmpF && !SetjmpF->use_empty();
   bool LongjmpUsed = LongjmpF && !LongjmpF->use_empty();
-  bool DoSjLj = EnableSjLj && (SetjmpUsed || LongjmpUsed);
+  DoSjLj = EnableSjLj && (SetjmpUsed || LongjmpUsed);
 
   auto *TPC = getAnalysisIfAvailable<TargetPassConfig>();
   assert(TPC && "Expected a TargetPassConfig");
@@ -718,7 +725,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
 
   bool Changed = false;
 
-  // Exception handling
+  // Function registration for exception handling
   if (EnableEH) {
     // Register __resumeException function
     FunctionType *ResumeFTy =
@@ -729,26 +736,15 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
     FunctionType *EHTypeIDTy =
         FunctionType::get(IRB.getInt32Ty(), IRB.getInt8PtrTy(), false);
     EHTypeIDF = getEmscriptenFunction(EHTypeIDTy, "llvm_eh_typeid_for", &M);
-
-    for (Function &F : M) {
-      if (F.isDeclaration())
-        continue;
-      Changed |= runEHOnFunction(F);
-    }
   }
 
-  // Setjmp/longjmp handling
+  // Function registration and data pre-gathering for setjmp/longjmp handling
   if (DoSjLj) {
-    Changed = true; // We have setjmp or longjmp somewhere
-
     // Register emscripten_longjmp function
     FunctionType *FTy = FunctionType::get(
         IRB.getVoidTy(), {getAddrIntType(&M), IRB.getInt32Ty()}, false);
     EmLongjmpF = getEmscriptenFunction(FTy, "emscripten_longjmp", &M);
 
-    if (LongjmpF)
-      replaceLongjmpWithEmscriptenLongjmp(LongjmpF, EmLongjmpF);
-
     if (SetjmpF) {
       // Register saveSetjmp function
       FunctionType *SetjmpFTy = SetjmpF->getFunctionType();
@@ -765,16 +761,33 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
           false);
       TestSetjmpF = getEmscriptenFunction(FTy, "testSetjmp", &M);
 
-      // Only traverse functions that uses setjmp in order not to insert
-      // unnecessary prep / cleanup code in every function
-      SmallPtrSet<Function *, 8> SetjmpUsers;
+      // Precompute setjmp users
       for (User *U : SetjmpF->users()) {
         auto *UI = cast<Instruction>(U);
         SetjmpUsers.insert(UI->getFunction());
       }
+    }
+  }
+
+  // Exception handling transformation
+  if (EnableEH) {
+    for (Function &F : M) {
+      if (F.isDeclaration())
+        continue;
+      Changed |= runEHOnFunction(F);
+    }
+  }
+
+  // Setjmp/longjmp handling transformation
+  if (DoSjLj) {
+    Changed = true; // We have setjmp or longjmp somewhere
+    if (LongjmpF)
+      replaceLongjmpWithEmscriptenLongjmp(LongjmpF, EmLongjmpF);
+    // Only traverse functions that uses setjmp in order not to insert
+    // unnecessary prep / cleanup code in every function
+    if (SetjmpF)
       for (Function *F : SetjmpUsers)
         runSjLjOnFunction(*F);
-    }
   }
 
   if (!Changed) {
@@ -802,8 +815,6 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) {
   bool Changed = false;
   SmallVector<Instruction *, 64> ToErase;
   SmallPtrSet<LandingPadInst *, 32> LandingPads;
-  bool AllowExceptions = areAllExceptionsAllowed() ||
-                         EHAllowlistSet.count(std::string(F.getName()));
 
   for (BasicBlock &BB : F) {
     auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
@@ -813,12 +824,51 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) {
     LandingPads.insert(II->getLandingPadInst());
     IRB.SetInsertPoint(II);
 
-    bool NeedInvoke = AllowExceptions && canThrow(II->getCalledOperand());
+    const Value *Callee = II->getCalledOperand();
+    bool NeedInvoke = supportsException(&F) && canThrow(Callee);
     if (NeedInvoke) {
       // Wrap invoke with invoke wrapper and generate preamble/postamble
       Value *Threw = wrapInvoke(II);
       ToErase.push_back(II);
 
+      // If setjmp/longjmp handling is enabled, the thrown value can be not an
+      // exception but a longjmp. If the current function contains calls to
+      // setjmp, it will be appropriately handled in runSjLjOnFunction. But even
+      // if the function does not contain setjmp calls, we shouldn't silently
+      // ignore longjmps; we should rethrow them so they can be correctly
+      // handled in somewhere up the call chain where setjmp is.
+      // __THREW__'s value is 0 when nothing happened, 1 when an exception is
+      // thrown, other values when longjmp is thrown.
+      //
+      // if (%__THREW__.val == 0 || %__THREW__.val == 1)
+      //   goto %tail
+      // else
+      //   goto %longjmp.rethrow
+      //
+      // longjmp.rethrow: ;; This is longjmp. Rethrow it
+      //   %__threwValue.val = __threwValue
+      //   emscripten_longjmp(%__THREW__.val, %__threwValue.val);
+      //
+      // tail: ;; Nothing happened or an exception is thrown
+      //   ... Continue exception handling ...
+      if (DoSjLj && !SetjmpUsers.count(&F) && canLongjmp(M, Callee)) {
+        BasicBlock *Tail = BasicBlock::Create(C, "tail", &F);
+        BasicBlock *RethrowBB = BasicBlock::Create(C, "longjmp.rethrow", &F);
+        Value *CmpEqOne =
+            IRB.CreateICmpEQ(Threw, getAddrSizeInt(&M, 1), "cmp.eq.one");
+        Value *CmpEqZero =
+            IRB.CreateICmpEQ(Threw, getAddrSizeInt(&M, 0), "cmp.eq.zero");
+        Value *Or = IRB.CreateOr(CmpEqZero, CmpEqOne, "or");
+        IRB.CreateCondBr(Or, Tail, RethrowBB);
+        IRB.SetInsertPoint(RethrowBB);
+        Value *ThrewValue = IRB.CreateLoad(IRB.getInt32Ty(), ThrewValueGV,
+                                           ThrewValueGV->getName() + ".val");
+        IRB.CreateCall(EmLongjmpF, {Threw, ThrewValue});
+
+        IRB.CreateUnreachable();
+        IRB.SetInsertPoint(Tail);
+      }
+
       // Insert a branch based on __THREW__ variable
       Value *Cmp = IRB.CreateICmpEQ(Threw, getAddrSizeInt(&M, 1), "cmp");
       IRB.CreateCondBr(Cmp, II->getUnwindDest(), II->getNormalDest());
@@ -1098,6 +1148,46 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runSjLjOnFunction(Function &F) {
         Threw = wrapInvoke(CI);
         ToErase.push_back(CI);
         Tail = SplitBlock(BB, CI->getNextNode());
+
+        // If exception handling is enabled, the thrown value can be not a
+        // longjmp but an exception, in which case we shouldn't silently ignore
+        // exceptions; we should rethrow them.
+        // __THREW__'s value is 0 when nothing happened, 1 when an exception is
+        // thrown, other values when longjmp is thrown.
+        //
+        // if (%__THREW__.val == 1)
+        //   goto %eh.rethrow
+        // else
+        //   goto %normal
+        //
+        // eh.rethrow: ;; Rethrow exception
+        //   %exn = call @__cxa_find_matching_catch_2() ;; Retrieve thrown ptr
+        //   __resumeException(%exn)
+        //
+        // normal:
+        //   <-- Insertion point. Will insert sjlj handling code from here
+        //   goto %tail
+        //
+        // tail:
+        //   ...
+        if (supportsException(&F) && canThrow(Callee)) {
+          IRB.SetInsertPoint(CI);
+          // We will add a new conditional branch. So remove the branch created
+          // when we split the BB
+          ToErase.push_back(BB->getTerminator());
+          BasicBlock *NormalBB = BasicBlock::Create(C, "normal", &F);
+          BasicBlock *RethrowBB = BasicBlock::Create(C, "eh.rethrow", &F);
+          Value *CmpEqOne =
+              IRB.CreateICmpEQ(Threw, getAddrSizeInt(&M, 1), "cmp.eq.one");
+          IRB.CreateCondBr(CmpEqOne, RethrowBB, NormalBB);
+          IRB.SetInsertPoint(RethrowBB);
+          CallInst *Exn = IRB.CreateCall(getFindMatchingCatch(M, 0), {}, "exn");
+          IRB.CreateCall(ResumeF, {Exn});
+          IRB.CreateUnreachable();
+          IRB.SetInsertPoint(NormalBB);
+          IRB.CreateBr(Tail);
+          BB = NormalBB; // New insertion point to insert testSetjmp()
+        }
       }
 
       // We need to replace the terminator in Tail - SplitBlock makes BB go

diff  --git a/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj.ll b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj.ll
new file mode 100644
index 0000000000000..7de4f2ccfd8e5
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj.ll
@@ -0,0 +1,132 @@
+; RUN: opt < %s -wasm-lower-em-ehsjlj -S | FileCheck %s
+; RUN: llc < %s
+
+; Tests for cases when exception handling and setjmp/longjmp handling are mixed.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+%struct.__jmp_buf_tag = type { [6 x i32], i32, [32 x i32] }
+
+; There is a function call (@foo) that can either throw an exception or longjmp
+; and there is also a setjmp call. When @foo throws, we have to check both for
+; exception and longjmp and jump to exception or longjmp handling BB depending
+; on the result.
+define void @setjmp_longjmp_exception() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; CHECK-LABEL: @setjmp_longjmp_exception
+entry:
+  %buf = alloca [1 x %struct.__jmp_buf_tag], align 16
+  %arraydecay = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
+  %call = call i32 @setjmp(%struct.__jmp_buf_tag* %arraydecay) #0
+  invoke void @foo()
+          to label %try.cont unwind label %lpad
+
+; CHECK:    entry.split:
+; CHECK:      %[[CMP0:.*]] = icmp ne i32 %__THREW__.val, 0
+; CHECK-NEXT: %__threwValue.val = load i32, i32* @__threwValue
+; CHECK-NEXT: %[[CMP1:.*]] = icmp ne i32 %__threwValue.val, 0
+; CHECK-NEXT: %[[CMP:.*]] = and i1 %[[CMP0]], %[[CMP1]]
+; CHECK-NEXT: br i1 %[[CMP]], label %if.then1, label %if.else1
+
+; This is exception checking part. %if.else1 leads here
+; CHECK:    entry.split.split:
+; CHECK-NEXT: %[[CMP:.*]] = icmp eq i32 %__THREW__.val, 1
+; CHECK-NEXT: br i1 %[[CMP]], label %lpad, label %try.cont
+
+; longjmp checking part
+; CHECK:    if.then1:
+; CHECK:      call i32 @testSetjmp
+
+lpad:                                             ; preds = %entry
+  %0 = landingpad { i8*, i32 }
+          catch i8* null
+  %1 = extractvalue { i8*, i32 } %0, 0
+  %2 = extractvalue { i8*, i32 } %0, 1
+  %3 = call i8* @__cxa_begin_catch(i8* %1) #2
+  call void @__cxa_end_catch()
+  br label %try.cont
+
+try.cont:                                         ; preds = %entry, %lpad
+  ret void
+}
+
+; @foo can either throw an exception or longjmp. Because this function doesn't
+; have any setjmp calls, we only handle exceptions in this function. But because
+; sjlj is enabled, we check if the thrown value is longjmp and if so rethrow it
+; by calling @emscripten_longjmp.
+define void @rethrow_longjmp() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; CHECK-LABEL: @rethrow_longjmp
+entry:
+  invoke void @foo()
+          to label %try.cont unwind label %lpad
+; CHECK:    entry:
+; CHECK:      %cmp.eq.one = icmp eq i32 %__THREW__.val, 1
+; CHECK-NEXT: %cmp.eq.zero = icmp eq i32 %__THREW__.val, 0
+; CHECK-NEXT: %or = or i1 %cmp.eq.zero, %cmp.eq.one
+; CHECK-NEXT: br i1 %or, label %tail, label %longjmp.rethrow
+
+; CHECK:    tail:
+; CHECK-NEXT: %cmp = icmp eq i32 %__THREW__.val, 1
+; CHECK-NEXT: br i1 %cmp, label %lpad, label %try.cont
+
+; CHECK:    longjmp.rethrow:
+; CHECK-NEXT: %__threwValue.val = load i32, i32* @__threwValue, align 4
+; CHECK-NEXT: call void @emscripten_longjmp(i32 %__THREW__.val, i32 %__threwValue.val)
+; CHECK-NEXT: unreachable
+
+lpad:                                             ; preds = %entry
+  %0 = landingpad { i8*, i32 }
+          catch i8* null
+  %1 = extractvalue { i8*, i32 } %0, 0
+  %2 = extractvalue { i8*, i32 } %0, 1
+  %3 = call i8* @__cxa_begin_catch(i8* %1) #5
+  call void @__cxa_end_catch()
+  br label %try.cont
+
+try.cont:                                         ; preds = %entry, %lpad
+  ret void
+}
+
+; This function contains a setjmp call and no invoke, so we only handle longjmp
+; here. But @foo can also throw an exception, so we check if an exception is
+; thrown and if so rethrow it by calling @__resumeException.
+define void @rethrow_exception() {
+; CHECK-LABEL: @rethrow_exception
+entry:
+  %buf = alloca [1 x %struct.__jmp_buf_tag], align 16
+  %arraydecay = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
+  %call = call i32 @setjmp(%struct.__jmp_buf_tag* %arraydecay) #0
+  %cmp = icmp ne i32 %call, 0
+  br i1 %cmp, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  call void @foo()
+  br label %return
+
+; CHECK:    if.end:
+; CHECK:      %cmp.eq.one = icmp eq i32 %__THREW__.val, 1
+; CHECK-NEXT: br i1 %cmp.eq.one, label %eh.rethrow, label %normal
+
+; CHECK:    normal:
+; CHECK-NEXT: icmp ne i32 %__THREW__.val, 0
+
+; CHECK:    eh.rethrow:
+; CHECK-NEXT: %exn = call i8* @__cxa_find_matching_catch_2()
+; CHECK-NEXT: call void @__resumeException(i8* %exn)
+; CHECK-NEXT: unreachable
+
+return:                                           ; preds = %entry, %if.end
+  ret void
+}
+
+declare void @foo()
+; Function Attrs: returns_twice
+declare i32 @setjmp(%struct.__jmp_buf_tag*)
+; Function Attrs: noreturn
+declare void @longjmp(%struct.__jmp_buf_tag*, i32)
+declare i32 @__gxx_personality_v0(...)
+declare i8* @__cxa_begin_catch(i8*)
+declare void @__cxa_end_catch()
+
+attributes #0 = { returns_twice }
+attributes #1 = { noreturn }

diff  --git a/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll b/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
index e918ac6b8031d..afac9422fbc9a 100644
--- a/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
+++ b/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
@@ -100,44 +100,6 @@ entry:
 ; CHECK-NEXT: ret void
 }
 
-; Test a case when a function call is within try-catch, after a setjmp
-define void @exception_and_longjmp() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
-; CHECK-LABEL: @exception_and_longjmp
-entry:
-  %buf = alloca [1 x %struct.__jmp_buf_tag], align 16
-  %arraydecay = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
-  %call = call i32 @setjmp(%struct.__jmp_buf_tag* %arraydecay) #0
-  invoke void @foo()
-          to label %try.cont unwind label %lpad
-
-; CHECK: entry.split:
-; CHECK: store [[PTR]] 0, [[PTR]]* @__THREW__
-; CHECK-NEXT: call cc{{.*}} void @__invoke_void(void ()* @foo)
-; CHECK-NEXT: %[[__THREW__VAL:.*]] = load [[PTR]], [[PTR]]* @__THREW__
-; CHECK-NEXT: store [[PTR]] 0, [[PTR]]* @__THREW__
-; CHECK-NEXT: %[[CMP0:.*]] = icmp ne [[PTR]] %[[__THREW__VAL]], 0
-; CHECK-NEXT: %[[THREWVALUE_VAL:.*]] = load i32, i32* @__threwValue
-; CHECK-NEXT: %[[CMP1:.*]] = icmp ne i32 %[[THREWVALUE_VAL]], 0
-; CHECK-NEXT: %[[CMP:.*]] = and i1 %[[CMP0]], %[[CMP1]]
-; CHECK-NEXT: br i1 %[[CMP]], label %if.then1, label %if.else1
-
-; CHECK: entry.split.split:
-; CHECK-NEXT: %[[CMP:.*]] = icmp eq [[PTR]] %[[__THREW__VAL]], 1
-; CHECK-NEXT: br i1 %[[CMP]], label %lpad, label %try.cont
-
-lpad:                                             ; preds = %entry
-  %0 = landingpad { i8*, i32 }
-          catch i8* null
-  %1 = extractvalue { i8*, i32 } %0, 0
-  %2 = extractvalue { i8*, i32 } %0, 1
-  %3 = call i8* @__cxa_begin_catch(i8* %1) #2
-  call void @__cxa_end_catch()
-  br label %try.cont
-
-try.cont:                                         ; preds = %entry, %lpad
-  ret void
-}
-
 ; Test SSA validity
 define void @ssa(i32 %n) {
 ; CHECK-LABEL: @ssa
@@ -283,7 +245,8 @@ entry:
   ret void
 }
 
-declare void @foo()
+; Function Attrs: nounwind
+declare void @foo() #2
 ; Function Attrs: returns_twice
 declare i32 @setjmp(%struct.__jmp_buf_tag*) #0
 ; Function Attrs: noreturn
@@ -311,7 +274,7 @@ attributes #3 = { allocsize(0) }
 ; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__resumeException" }
 ; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="llvm_eh_typeid_for" }
 ; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__invoke_void" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__cxa_find_matching_catch_3" }
+; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__cxa_find_matching_catch_2" }
 ; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="saveSetjmp" }
 ; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="testSetjmp" }
 ; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="emscripten_longjmp" }


        


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