[llvm] r280302 - Add asm.js-style setjmp/longjmp handling for wasm

Heejin Ahn via llvm-commits llvm-commits at lists.llvm.org
Wed Aug 31 15:40:35 PDT 2016


Author: aheejin
Date: Wed Aug 31 17:40:34 2016
New Revision: 280302

URL: http://llvm.org/viewvc/llvm-project?rev=280302&view=rev
Log:
Add asm.js-style setjmp/longjmp handling for wasm

Summary: This patch adds asm.js-style setjmp/longjmp handling support for WebAssembly. It also uses JavaScript's try and catch mechanism.

Reviewers: jpp, dschuff

Subscribers: jfb, dschuff

Differential Revision: https://reviews.llvm.org/D23928

Added:
    llvm/trunk/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
    llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll
Modified:
    llvm/trunk/lib/Target/WebAssembly/LLVMBuild.txt
    llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
    llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
    llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions-whitelist.ll
    llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll

Modified: llvm/trunk/lib/Target/WebAssembly/LLVMBuild.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/LLVMBuild.txt?rev=280302&r1=280301&r2=280302&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/LLVMBuild.txt (original)
+++ llvm/trunk/lib/Target/WebAssembly/LLVMBuild.txt Wed Aug 31 17:40:34 2016
@@ -29,5 +29,5 @@ has_disassembler = 1
 type = Library
 name = WebAssemblyCodeGen
 parent = WebAssembly
-required_libraries = Analysis AsmPrinter CodeGen Core MC Scalar SelectionDAG Support Target WebAssemblyAsmPrinter WebAssemblyDesc WebAssemblyInfo
+required_libraries = Analysis AsmPrinter CodeGen Core MC Scalar SelectionDAG Support Target TransformUtils WebAssemblyAsmPrinter WebAssemblyDesc WebAssemblyInfo
 add_to_library_groups = WebAssembly

Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp?rev=280302&r1=280301&r2=280302&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp Wed Aug 31 17:40:34 2016
@@ -8,25 +8,62 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// \brief This file lowers exception-related instructions in order to use
-/// Emscripten's JavaScript try and catch mechanism to handle exceptions.
+/// \brief This file lowers exception-related instructions and setjmp/longjmp
+/// function calls in order to use Emscripten's JavaScript try and catch
+/// mechanism.
 ///
-/// To handle exceptions, this scheme relies on JavaScript's try and catch
-/// syntax and relevant exception-related libraries implemented in JavaScript
-/// glue code that will be produced by Emscripten. This is similar to the
-/// current Emscripten asm.js exception handling in fastcomp.
-/// For fastcomp's EH scheme, see these files in fastcomp LLVM branch:
+/// To handle exceptions and setjmp/longjmps, this scheme relies on JavaScript's
+/// try and catch syntax and relevant exception-related libraries implemented
+/// in JavaScript glue code that will be produced by Emscripten. This is similar
+/// to the current Emscripten asm.js exception handling in fastcomp. For
+/// fastcomp's EH / SjLj scheme, see these files in fastcomp LLVM branch:
 /// (Location: https://github.com/kripken/emscripten-fastcomp)
 /// lib/Target/JSBackend/NaCl/LowerEmExceptionsPass.cpp
+/// lib/Target/JSBackend/NaCl/LowerEmSetjmp.cpp
 /// lib/Target/JSBackend/JSBackend.cpp
 /// lib/Target/JSBackend/CallHandlers.h
 ///
-/// This pass does following things:
+/// * Exception handling
+/// This pass lowers invokes and landingpads into library functions in JS glue
+/// code. Invokes are lowered into function wrappers called invoke wrappers that
+/// exist in JS side, which wraps the original function call with JS try-catch.
+/// If an exception occurred, cxa_throw() function in JS side sets some
+/// variables (see below) so we can check whether an exception occurred from
+/// wasm code and handle it appropriately.
 ///
-/// 1) Create three global variables: __THREW__, __threwValue, and tempRet0.
-///    tempRet0 will be set within __cxa_find_matching_catch() function in
+/// * Setjmp-longjmp handling
+/// This pass lowers setjmp to a reasonably-performant approach for emscripten.
+/// The idea is that each block with a setjmp is broken up into two parts: the
+/// part containing setjmp and the part right after the setjmp. The latter part
+/// is either reached from the setjmp, or later from a longjmp. To handle the
+/// longjmp, all calls that might longjmp are also called using invoke wrappers
+/// and thus JS / try-catch. JS longjmp() function also sets some variables so
+/// we can check / whether a longjmp occurred from wasm code. Each block with a
+/// function call that might longjmp is also split up after the longjmp call.
+/// After the longjmp call, we check whether a longjmp occurred, and if it did,
+/// which setjmp it corresponds to, and jump to the right post-setjmp block.
+/// We assume setjmp-longjmp handling always run after EH handling, which means
+/// we don't expect any exception-related instructions when SjLj runs.
+/// FIXME Currently this scheme does not support indirect call of setjmp,
+/// because of the limitation of the scheme itself. fastcomp does not support it
+/// either.
+///
+/// In detail, 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
 ///    JS library, and __THREW__ and __threwValue will be set in invoke wrappers
-///    in JS glue code. For what invoke wrappers are, refer to 3).
+///    in JS glue code. For what invoke wrappers are, refer to 3). These
+///    variables are used for both exceptions and setjmp/longjmps.
+///    __THREW__ indicates whether an exception or a longjmp occurred or not. 0
+///    means nothing occurred, 1 means an exception occurred, and other numbers
+///    mean a longjmp occurred. In the case of longjmp, threwValue variable
+///    indicates the corresponding setjmp buffer the longjmp corresponds to.
+///    In exception handling, __tempRet0 indicates the type of an exception
+///    caught, and in setjmp/longjmp, it means the second argument to longjmp
+///    function.
+///
+/// * Exception handling
 ///
 /// 2) Create setThrew and setTempRet0 functions.
 ///    The global variables created in 1) will exist in wasm address space,
@@ -43,7 +80,7 @@
 ///    }
 ///
 ///    function setTempRet0(value) {
-///      tempRet0 = value;
+///      __tempRet0 = value;
 ///    }
 ///
 /// 3) Lower
@@ -78,10 +115,10 @@
 ///      ... use %val ...
 ///    into
 ///      %fmc = call @__cxa_find_matching_catch_N(c1, c2, c3, ...)
-///      %val = {%fmc, tempRet0}
+///      %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
@@ -96,14 +133,81 @@
 ///      call @llvm_eh_typeid_for(type)
 ///    llvm_eh_typeid_for function will be generated in JS glue code.
 ///
+/// * Setjmp / Longjmp handling
+///
+/// 7) In the function entry that calls setjmp, initialize setjmpTable and
+///    sejmpTableSize as follows:
+///      setjmpTableSize = 4;
+///      setjmpTable = (int *) malloc(40);
+///      setjmpTable[0] = 0;
+///    setjmpTable and setjmpTableSize are used in saveSetjmp() function in JS
+///    code.
+///
+/// 8) Lower
+///      setjmp(buf)
+///    into
+///      setjmpTable = saveSetjmp(buf, label, setjmpTable, setjmpTableSize);
+///      setjmpTableSize = __tempRet0;
+///    For each dynamic setjmp call, setjmpTable stores its ID (a number which
+///    is incrementally assigned from 0) and its label (a unique number that
+///    represents each callsite of setjmp). When we need more entries in
+///    setjmpTable, it is reallocated in saveSetjmp() in JS code and it will
+///    return the new table address, and assign the new table size in
+///    __tempRet0. saveSetjmp also stores the setjmp's ID into the buffer buf.
+///    A BB with setjmp is split into two after setjmp call in order to make the
+///    post-setjmp BB the possible destination of longjmp BB.
+///
+/// 9) Lower
+///      longjmp(buf, value)
+///    into
+///      emscripten_longjmp_jmpbuf(buf, value)
+///    emscripten_longjmp_jmpbuf will be lowered to emscripten_longjmp later.
+///
+/// 10) Lower every call that might longjmp into
+///      __THREW__ = 0;
+///      call @invoke_SIG(func, arg1, arg2)
+///      %__THREW__.val = __THREW__;
+///      __THREW__ = 0;
+///      if (%__THREW__.val != 0 & threwValue != 0) {
+///        %label = testSetjmp(mem[%__THREW__.val], setjmpTable,
+///                            setjmpTableSize);
+///        if (%label == 0)
+///          emscripten_longjmp(%__THREW__.val, threwValue);
+///        __tempRet0 = threwValue;
+///      } else {
+///        %label = -1;
+///      }
+///      longjmp_result = __tempRet0;
+///      switch label {
+///        label 1: post-setjmp BB 1
+///        label 2: post-setjmp BB 2
+///        ...
+///        default: splited next BB
+///      }
+///     testSetjmp examines setjmpTable to see if there is a matching setjmp
+///     call. After calling an invoke wrapper, if a longjmp occurred, __THREW__
+///     will be the address of matching jmp_buf buffer and threwValue be the
+///     second argument to longjmp. mem[__THREW__.val] is a setjmp ID that is
+///     stored in saveSetjmp. testSetjmp returns a setjmp label, a unique ID to
+///     each setjmp callsite. Label 0 means this longjmp buffer does not
+///     correspond to one of the setjmp callsites in this function, so in this
+///     case we just chain the longjmp to the caller. (Here we call
+///     emscripten_longjmp, which is different from emscripten_longjmp_jmpbuf.
+///     emscripten_longjmp_jmpbuf takes jmp_buf as its first argument, while
+///     emscripten_longjmp takes an int. Both of them will eventually be lowered
+///     to emscripten_longjmp in s2wasm, but here we need two signatures - we
+///     can't translate an int value to a jmp_buf.)
+///     Label -1 means no longjmp occurred. Otherwise we jump to the right
+///     post-setjmp BB based on the label.
+///
 ///===----------------------------------------------------------------------===//
 
 #include "WebAssembly.h"
 #include "llvm/IR/CallSite.h"
+#include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/Module.h"
-#include "llvm/Support/raw_ostream.h"
-#include <set>
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
 
 using namespace llvm;
 
@@ -125,17 +229,26 @@ class WebAssemblyLowerEmscriptenEHSjLj f
   static const char *EHTypeIDFName;
   static const char *SetThrewFName;
   static const char *SetTempRet0FName;
+  static const char *EmLongjmpFName;
+  static const char *EmLongjmpJmpbufFName;
+  static const char *SaveSetjmpFName;
+  static const char *TestSetjmpFName;
   static const char *FindMatchingCatchPrefix;
   static const char *InvokePrefix;
 
-  bool DoEH;   // Enable exception handling
-  bool DoSjLj; // Enable setjmp/longjmp handling
+  bool EnableEH;   // Enable exception handling
+  bool EnableSjLj; // Enable setjmp/longjmp handling
 
   GlobalVariable *ThrewGV;
   GlobalVariable *ThrewValueGV;
   GlobalVariable *TempRet0GV;
   Function *ResumeF;
   Function *EHTypeIDF;
+  Function *EmLongjmpF;
+  Function *EmLongjmpJmpbufF;
+  Function *SaveSetjmpF;
+  Function *TestSetjmpF;
+
   // __cxa_find_matching_catch_N functions.
   // Indexed by the number of clauses in an original landingpad instruction.
   DenseMap<int, Function *> FindMatchingCatches;
@@ -150,26 +263,37 @@ class WebAssemblyLowerEmscriptenEHSjLj f
 
   bool runEHOnFunction(Function &F);
   bool runSjLjOnFunction(Function &F);
-  // 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
-  // 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);
+  template <typename CallOrInvoke> Value *wrapInvoke(CallOrInvoke *CI);
+  void wrapTestSetjmp(BasicBlock *BB, Instruction *InsertPt, Value *Threw,
+                      Value *SetjmpTable, Value *SetjmpTableSize, Value *&Label,
+                      Value *&LongjmpResult, BasicBlock *&EndBB);
+  template <typename CallOrInvoke> Function *getInvokeWrapper(CallOrInvoke *CI);
+
   bool areAllExceptionsAllowed() const { return EHWhitelistSet.empty(); }
+  bool canLongjmp(Module &M, const Value *Callee) const;
+
+  void createSetThrewFunction(Module &M);
+  void createSetTempRet0Function(Module &M);
+
+  void rebuildSSA(Function &F);
 
 public:
   static char ID;
 
-  WebAssemblyLowerEmscriptenEHSjLj(bool DoEH = true, bool DoSjLj = true)
-      : ModulePass(ID), DoEH(DoEH), DoSjLj(DoSjLj), ThrewGV(nullptr),
-        ThrewValueGV(nullptr), TempRet0GV(nullptr), ResumeF(nullptr),
-        EHTypeIDF(nullptr) {
+  WebAssemblyLowerEmscriptenEHSjLj(bool EnableEH = true, bool EnableSjLj = true)
+      : ModulePass(ID), EnableEH(EnableEH), EnableSjLj(EnableSjLj),
+        ThrewGV(nullptr), ThrewValueGV(nullptr), TempRet0GV(nullptr),
+        ResumeF(nullptr), EHTypeIDF(nullptr), EmLongjmpF(nullptr),
+        EmLongjmpJmpbufF(nullptr), SaveSetjmpF(nullptr), TestSetjmpF(nullptr) {
     EHWhitelistSet.insert(EHWhitelist.begin(), EHWhitelist.end());
   }
   bool runOnModule(Module &M) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<DominatorTreeWrapperPass>();
+  }
 };
 } // End anonymous namespace
 
@@ -181,6 +305,12 @@ const char *WebAssemblyLowerEmscriptenEH
     "llvm_eh_typeid_for";
 const char *WebAssemblyLowerEmscriptenEHSjLj::SetThrewFName = "setThrew";
 const char *WebAssemblyLowerEmscriptenEHSjLj::SetTempRet0FName = "setTempRet0";
+const char *WebAssemblyLowerEmscriptenEHSjLj::EmLongjmpFName =
+    "emscripten_longjmp";
+const char *WebAssemblyLowerEmscriptenEHSjLj::EmLongjmpJmpbufFName =
+    "emscripten_longjmp_jmpbuf";
+const char *WebAssemblyLowerEmscriptenEHSjLj::SaveSetjmpFName = "saveSetjmp";
+const char *WebAssemblyLowerEmscriptenEHSjLj::TestSetjmpFName = "testSetjmp";
 const char *WebAssemblyLowerEmscriptenEHSjLj::FindMatchingCatchPrefix =
     "__cxa_find_matching_catch_";
 const char *WebAssemblyLowerEmscriptenEHSjLj::InvokePrefix = "__invoke_";
@@ -190,9 +320,9 @@ INITIALIZE_PASS(WebAssemblyLowerEmscript
                 "WebAssembly Lower Emscripten Exceptions / Setjmp / Longjmp",
                 false, false)
 
-ModulePass *llvm::createWebAssemblyLowerEmscriptenEHSjLj(bool DoEH,
-                                                         bool DoSjLj) {
-  return new WebAssemblyLowerEmscriptenEHSjLj(DoEH, DoSjLj);
+ModulePass *llvm::createWebAssemblyLowerEmscriptenEHSjLj(bool EnableEH,
+                                                         bool EnableSjLj) {
+  return new WebAssemblyLowerEmscriptenEHSjLj(EnableEH, EnableSjLj);
 }
 
 static bool canThrow(const Value *V) {
@@ -204,7 +334,7 @@ static bool canThrow(const Value *V) {
     // leave setjmp and longjmp (mostly) alone, we process them properly later
     if (Name == "setjmp" || Name == "longjmp")
       return false;
-    return true;
+    return !F->doesNotThrow();
   }
   // not a function, so an indirect call - can throw, we can't tell
   return true;
@@ -242,6 +372,11 @@ static std::string getSignature(Function
   return Sig;
 }
 
+// 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
+// functions are named after the number of arguments in the original landingpad
+// instruction.
 Function *
 WebAssemblyLowerEmscriptenEHSjLj::getFindMatchingCatch(Module &M,
                                                        unsigned NumClauses) {
@@ -257,15 +392,86 @@ WebAssemblyLowerEmscriptenEHSjLj::getFin
   return F;
 }
 
-Function *WebAssemblyLowerEmscriptenEHSjLj::getInvokeWrapper(Module &M,
-                                                             InvokeInst *II) {
+// Generate invoke wrapper seqence with preamble and postamble
+// Preamble:
+// __THREW__ = 0;
+// Postamble:
+// %__THREW__.val = __THREW__; __THREW__ = 0;
+// Returns %__THREW__.val, which indicates whether an exception is thrown (or
+// whether longjmp occurred), for future use.
+template <typename CallOrInvoke>
+Value *WebAssemblyLowerEmscriptenEHSjLj::wrapInvoke(CallOrInvoke *CI) {
+  LLVMContext &C = CI->getModule()->getContext();
+
+  // 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 (CI->doesNotReturn()) {
+    if (auto *F = dyn_cast<Function>(CI->getCalledValue()))
+      F->removeFnAttr(Attribute::NoReturn);
+    CI->removeAttribute(AttributeSet::FunctionIndex, Attribute::NoReturn);
+  }
+
+  IRBuilder<> IRB(C);
+  IRB.SetInsertPoint(CI);
+
+  // Pre-invoke
+  // __THREW__ = 0;
+  IRB.CreateStore(IRB.getInt32(0), ThrewGV);
+
+  // Invoke function wrapper in JavaScript
+  SmallVector<Value *, 16> Args;
+  // Put the pointer to the callee as first argument, so it can be called
+  // within the invoke wrapper later
+  Args.push_back(CI->getCalledValue());
+  Args.append(CI->arg_begin(), CI->arg_end());
+  CallInst *NewCall = IRB.CreateCall(getInvokeWrapper(CI), Args);
+  NewCall->takeName(CI);
+  NewCall->setCallingConv(CI->getCallingConv());
+  NewCall->setDebugLoc(CI->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 = CI->getAttributes();
+  CallSite::arg_iterator AI = CI->arg_begin();
+  unsigned i = 1; // Argument attribute index starts from 1
+  for (unsigned e = CI->getNumArgOperands(); i <= e; ++AI, ++i) {
+    if (InvokePAL.hasAttributes(i)) {
+      AttrBuilder B(InvokePAL, i);
+      AttributesVec.push_back(AttributeSet::get(C, i + 1, B));
+    }
+  }
+  // Add any return attributes.
+  if (InvokePAL.hasAttributes(AttributeSet::ReturnIndex))
+    AttributesVec.push_back(AttributeSet::get(C, InvokePAL.getRetAttributes()));
+  // Add any function attributes.
+  if (InvokePAL.hasAttributes(AttributeSet::FunctionIndex))
+    AttributesVec.push_back(AttributeSet::get(C, InvokePAL.getFnAttributes()));
+  // Reconstruct the AttributesList based on the vector we constructed.
+  AttributeSet NewCallPAL = AttributeSet::get(C, AttributesVec);
+  NewCall->setAttributes(NewCallPAL);
+
+  CI->replaceAllUsesWith(NewCall);
+
+  // Post-invoke
+  // %__THREW__.val = __THREW__; __THREW__ = 0;
+  Value *Threw = IRB.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
+  IRB.CreateStore(IRB.getInt32(0), ThrewGV);
+  return Threw;
+}
+
+// Get matching invoke wrapper based on callee signature
+template <typename CallOrInvoke>
+Function *WebAssemblyLowerEmscriptenEHSjLj::getInvokeWrapper(CallOrInvoke *CI) {
+  Module *M = CI->getModule();
   SmallVector<Type *, 16> ArgTys;
-  Value *Callee = II->getCalledValue();
+  Value *Callee = CI->getCalledValue();
   FunctionType *CalleeFTy;
   if (auto *F = dyn_cast<Function>(Callee))
     CalleeFTy = F->getFunctionType();
   else {
-    auto *CalleeTy = dyn_cast<PointerType>(Callee->getType())->getElementType();
+    auto *CalleeTy = cast<PointerType>(Callee->getType())->getElementType();
     CalleeFTy = dyn_cast<FunctionType>(CalleeTy);
   }
 
@@ -281,42 +487,243 @@ Function *WebAssemblyLowerEmscriptenEHSj
   FunctionType *FTy = FunctionType::get(CalleeFTy->getReturnType(), ArgTys,
                                         CalleeFTy->isVarArg());
   Function *F = Function::Create(FTy, GlobalValue::ExternalLinkage,
-                                 InvokePrefix + Sig, &M);
+                                 InvokePrefix + Sig, M);
   InvokeWrappers[Sig] = F;
   return F;
 }
 
+bool WebAssemblyLowerEmscriptenEHSjLj::canLongjmp(Module &M,
+                                                  const Value *Callee) const {
+  if (auto *CalleeF = dyn_cast<Function>(Callee))
+    if (CalleeF->isIntrinsic())
+      return false;
+
+  // The reason we include malloc/free here is to exclude the malloc/free
+  // calls generated in setjmp prep / cleanup routines.
+  Function *SetjmpF = M.getFunction("setjmp");
+  Function *MallocF = M.getFunction("malloc");
+  Function *FreeF = M.getFunction("free");
+  if (Callee == SetjmpF || Callee == MallocF || Callee == FreeF)
+    return false;
+
+  // There are functions in JS glue code
+  if (Callee == ResumeF || Callee == EHTypeIDF || Callee == SaveSetjmpF ||
+      Callee == TestSetjmpF)
+    return false;
+
+  // __cxa_find_matching_catch_N functions cannot longjmp
+  if (Callee->getName().startswith(FindMatchingCatchPrefix))
+    return false;
+
+  // Exception-catching related functions
+  Function *BeginCatchF = M.getFunction("__cxa_begin_catch");
+  Function *EndCatchF = M.getFunction("__cxa_end_catch");
+  Function *AllocExceptionF = M.getFunction("__cxa_allocate_exception");
+  Function *ThrowF = M.getFunction("__cxa_throw");
+  Function *TerminateF = M.getFunction("__clang_call_terminate");
+  if (Callee == BeginCatchF || Callee == EndCatchF ||
+      Callee == AllocExceptionF || Callee == ThrowF || Callee == TerminateF)
+    return false;
+
+  // Otherwise we don't know
+  return true;
+}
+
+// Generate testSetjmp function call seqence with preamble and postamble.
+// The code this generates is equivalent to the following JavaScript code:
+// if (%__THREW__.val != 0 & threwValue != 0) {
+//   %label = _testSetjmp(mem[%__THREW__.val], setjmpTable, setjmpTableSize);
+//   if (%label == 0)
+//     emscripten_longjmp(%__THREW__.val, threwValue);
+//   __tempRet0 = threwValue;
+// } else {
+//   %label = -1;
+// }
+// %longjmp_result = __tempRet0;
+//
+// As output parameters. returns %label, %longjmp_result, and the BB the last
+// instruction (%longjmp_result = ...) is in.
+void WebAssemblyLowerEmscriptenEHSjLj::wrapTestSetjmp(
+    BasicBlock *BB, Instruction *InsertPt, Value *Threw, Value *SetjmpTable,
+    Value *SetjmpTableSize, Value *&Label, Value *&LongjmpResult,
+    BasicBlock *&EndBB) {
+  Function *F = BB->getParent();
+  LLVMContext &C = BB->getModule()->getContext();
+  IRBuilder<> IRB(C);
+  IRB.SetInsertPoint(InsertPt);
+
+  // if (%__THREW__.val != 0 & threwValue != 0)
+  IRB.SetInsertPoint(BB);
+  BasicBlock *ThenBB1 = BasicBlock::Create(C, "if.then1", F);
+  BasicBlock *ElseBB1 = BasicBlock::Create(C, "if.else1", F);
+  BasicBlock *EndBB1 = BasicBlock::Create(C, "if.end", F);
+  Value *ThrewCmp = IRB.CreateICmpNE(Threw, IRB.getInt32(0));
+  Value *ThrewValue =
+      IRB.CreateLoad(ThrewValueGV, ThrewValueGV->getName() + ".val");
+  Value *ThrewValueCmp = IRB.CreateICmpNE(ThrewValue, IRB.getInt32(0));
+  Value *Cmp1 = IRB.CreateAnd(ThrewCmp, ThrewValueCmp, "cmp1");
+  IRB.CreateCondBr(Cmp1, ThenBB1, ElseBB1);
+
+  // %label = _testSetjmp(mem[%__THREW__.val], _setjmpTable, _setjmpTableSize);
+  // if (%label == 0)
+  IRB.SetInsertPoint(ThenBB1);
+  BasicBlock *ThenBB2 = BasicBlock::Create(C, "if.then2", F);
+  BasicBlock *EndBB2 = BasicBlock::Create(C, "if.end2", F);
+  Value *ThrewInt = IRB.CreateIntToPtr(Threw, Type::getInt32PtrTy(C),
+                                       Threw->getName() + ".i32p");
+  Value *LoadedThrew =
+      IRB.CreateLoad(ThrewInt, ThrewInt->getName() + ".loaded");
+  Value *ThenLabel = IRB.CreateCall(
+      TestSetjmpF, {LoadedThrew, SetjmpTable, SetjmpTableSize}, "label");
+  Value *Cmp2 = IRB.CreateICmpEQ(ThenLabel, IRB.getInt32(0));
+  IRB.CreateCondBr(Cmp2, ThenBB2, EndBB2);
+
+  // emscripten_longjmp(%__THREW__.val, threwValue);
+  IRB.SetInsertPoint(ThenBB2);
+  IRB.CreateCall(EmLongjmpF, {Threw, ThrewValue});
+  IRB.CreateUnreachable();
+
+  // __tempRet0 = threwValue;
+  IRB.SetInsertPoint(EndBB2);
+  IRB.CreateStore(ThrewValue, TempRet0GV);
+  IRB.CreateBr(EndBB1);
+
+  IRB.SetInsertPoint(ElseBB1);
+  IRB.CreateBr(EndBB1);
+
+  // longjmp_result = __tempRet0;
+  IRB.SetInsertPoint(EndBB1);
+  PHINode *LabelPHI = IRB.CreatePHI(IRB.getInt32Ty(), 2, "label");
+  LabelPHI->addIncoming(ThenLabel, EndBB2);
+
+  LabelPHI->addIncoming(IRB.getInt32(-1), ElseBB1);
+
+  // Output parameter assignment
+  Label = LabelPHI;
+  EndBB = EndBB1;
+  LongjmpResult = IRB.CreateLoad(TempRet0GV, "longjmp_result");
+}
+
+// Create setThrew function
+// function setThrew(threw, value) {
+//   if (__THREW__ == 0) {
+//     __THREW__ = threw;
+//     __threwValue = value;
+//   }
+// }
+void WebAssemblyLowerEmscriptenEHSjLj::createSetThrewFunction(Module &M) {
+  LLVMContext &C = M.getContext();
+  IRBuilder<> IRB(C);
+
+  assert(!M.getNamedGlobal(SetThrewFName) && "setThrew already exists");
+  Type *Params[] = {IRB.getInt32Ty(), IRB.getInt32Ty()};
+  FunctionType *FTy = FunctionType::get(IRB.getVoidTy(), Params, false);
+  Function *F =
+      Function::Create(FTy, GlobalValue::ExternalLinkage, SetThrewFName, &M);
+  Argument *Arg1 = &*(F->arg_begin());
+  Argument *Arg2 = &*(++F->arg_begin());
+  Arg1->setName("threw");
+  Arg2->setName("value");
+  BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
+  BasicBlock *ThenBB = BasicBlock::Create(C, "if.then", F);
+  BasicBlock *EndBB = BasicBlock::Create(C, "if.end", F);
+
+  IRB.SetInsertPoint(EntryBB);
+  Value *Threw = IRB.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
+  Value *Cmp = IRB.CreateICmpEQ(Threw, IRB.getInt32(0), "cmp");
+  IRB.CreateCondBr(Cmp, ThenBB, EndBB);
+
+  IRB.SetInsertPoint(ThenBB);
+  IRB.CreateStore(Arg1, ThrewGV);
+  IRB.CreateStore(Arg2, ThrewValueGV);
+  IRB.CreateBr(EndBB);
+
+  IRB.SetInsertPoint(EndBB);
+  IRB.CreateRetVoid();
+}
+
+// Create setTempRet0 function
+// function setTempRet0(value) {
+//   __tempRet0 = value;
+// }
+void WebAssemblyLowerEmscriptenEHSjLj::createSetTempRet0Function(Module &M) {
+  LLVMContext &C = M.getContext();
+  IRBuilder<> IRB(C);
+
+  assert(!M.getNamedGlobal(SetTempRet0FName) && "setTempRet0 already exists");
+  Type *Params[] = {IRB.getInt32Ty()};
+  FunctionType *FTy = FunctionType::get(IRB.getVoidTy(), Params, false);
+  Function *F =
+      Function::Create(FTy, GlobalValue::ExternalLinkage, SetTempRet0FName, &M);
+  F->arg_begin()->setName("value");
+  BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
+  IRB.SetInsertPoint(EntryBB);
+  IRB.CreateStore(&*F->arg_begin(), TempRet0GV);
+  IRB.CreateRetVoid();
+}
+
+void WebAssemblyLowerEmscriptenEHSjLj::rebuildSSA(Function &F) {
+  DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
+  DT.recalculate(F); // CFG has been changed
+  SSAUpdater SSA;
+  for (BasicBlock &BB : F) {
+    for (Instruction &I : BB) {
+      for (auto UI = I.use_begin(), UE = I.use_end(); UI != UE;) {
+        Use &U = *UI;
+        ++UI;
+        SSA.Initialize(I.getType(), I.getName());
+        SSA.AddAvailableValue(&BB, &I);
+        Instruction *User = cast<Instruction>(U.getUser());
+        if (User->getParent() == &BB)
+          continue;
+
+        if (PHINode *UserPN = dyn_cast<PHINode>(User))
+          if (UserPN->getIncomingBlock(U) == &BB)
+            continue;
+
+        if (DT.dominates(&I, User))
+          continue;
+        SSA.RewriteUseAfterInsertions(U);
+      }
+    }
+  }
+}
+
 bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
   LLVMContext &C = M.getContext();
   IRBuilder<> IRB(C);
-  IntegerType *Int1Ty = IRB.getInt1Ty();
-  PointerType *Int8PtrTy = IRB.getInt8PtrTy();
-  IntegerType *Int32Ty = IRB.getInt32Ty();
-  Type *VoidTy = IRB.getVoidTy();
 
-  // Create global variables __THREW__, threwValue, and tempRet0, which are
+  Function *SetjmpF = M.getFunction("setjmp");
+  Function *LongjmpF = M.getFunction("longjmp");
+  bool SetjmpUsed = SetjmpF && !SetjmpF->use_empty();
+  bool LongjmpUsed = LongjmpF && !LongjmpF->use_empty();
+  bool DoSjLj = EnableSjLj && (SetjmpUsed || LongjmpUsed);
+
+  // Create global variables __THREW__, threwValue, and __tempRet0, which are
   // used in common for both exception handling and setjmp/longjmp handling
-  ThrewGV =
-      new GlobalVariable(M, Int1Ty, false, GlobalValue::ExternalLinkage,
-                         IRB.getFalse(), createGlobalValueName(M, ThrewGVName));
+  ThrewGV = new GlobalVariable(M, IRB.getInt32Ty(), false,
+                               GlobalValue::ExternalLinkage, IRB.getInt32(0),
+                               createGlobalValueName(M, ThrewGVName));
   ThrewValueGV = new GlobalVariable(
-      M, Int32Ty, false, GlobalValue::ExternalLinkage, IRB.getInt32(0),
+      M, IRB.getInt32Ty(), false, GlobalValue::ExternalLinkage, IRB.getInt32(0),
       createGlobalValueName(M, ThrewValueGVName));
-  TempRet0GV = new GlobalVariable(M, Int32Ty, false,
+  TempRet0GV = new GlobalVariable(M, IRB.getInt32Ty(), false,
                                   GlobalValue::ExternalLinkage, IRB.getInt32(0),
                                   createGlobalValueName(M, TempRet0GVName));
 
   bool Changed = false;
 
   // Exception handling
-  if (DoEH) {
+  if (EnableEH) {
     // Register __resumeException function
-    FunctionType *ResumeFTy = FunctionType::get(VoidTy, Int8PtrTy, false);
+    FunctionType *ResumeFTy =
+        FunctionType::get(IRB.getVoidTy(), IRB.getInt8PtrTy(), false);
     ResumeF = Function::Create(ResumeFTy, GlobalValue::ExternalLinkage,
                                ResumeFName, &M);
 
     // Register llvm_eh_typeid_for function
-    FunctionType *EHTypeIDTy = FunctionType::get(Int32Ty, Int8PtrTy, false);
+    FunctionType *EHTypeIDTy =
+        FunctionType::get(IRB.getInt32Ty(), IRB.getInt8PtrTy(), false);
     EHTypeIDF = Function::Create(EHTypeIDTy, GlobalValue::ExternalLinkage,
                                  EHTypeIDFName, &M);
 
@@ -327,61 +734,80 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
     }
   }
 
-  // TODO: Run CFGSimplify like the emscripten JSBackend?
-
   // Setjmp/longjmp handling
   if (DoSjLj) {
-    for (Function &F : M) {
-      if (F.isDeclaration())
-        continue;
-      Changed |= runSjLjOnFunction(F);
+    Changed = true; // We have setjmp or longjmp somewhere
+
+    Function *MallocF = M.getFunction("malloc");
+    Function *FreeF = M.getFunction("free");
+    if (!MallocF || !FreeF)
+      report_fatal_error(
+          "malloc and free must be linked into the module if setjmp is used");
+
+    // Register saveSetjmp function
+    FunctionType *SetjmpFTy = SetjmpF->getFunctionType();
+    SmallVector<Type *, 4> Params = {SetjmpFTy->getParamType(0),
+                                     IRB.getInt32Ty(), Type::getInt32PtrTy(C),
+                                     IRB.getInt32Ty()};
+    FunctionType *FTy =
+        FunctionType::get(Type::getInt32PtrTy(C), Params, false);
+    SaveSetjmpF = Function::Create(FTy, GlobalValue::ExternalLinkage,
+                                   SaveSetjmpFName, &M);
+
+    // Register testSetjmp function
+    Params = {IRB.getInt32Ty(), Type::getInt32PtrTy(C), IRB.getInt32Ty()};
+    FTy = FunctionType::get(IRB.getInt32Ty(), Params, false);
+    TestSetjmpF = Function::Create(FTy, GlobalValue::ExternalLinkage,
+                                   TestSetjmpFName, &M);
+
+    if (LongjmpF) {
+      // Replace all uses of longjmp with emscripten_longjmp_jmpbuf, which is
+      // defined in JS code
+      EmLongjmpJmpbufF = Function::Create(LongjmpF->getFunctionType(),
+                                          GlobalValue::ExternalLinkage,
+                                          EmLongjmpJmpbufFName, &M);
+
+      LongjmpF->replaceAllUsesWith(EmLongjmpJmpbufF);
+    }
+    FTy = FunctionType::get(IRB.getVoidTy(),
+                            {IRB.getInt32Ty(), IRB.getInt32Ty()}, false);
+    EmLongjmpF =
+        Function::Create(FTy, GlobalValue::ExternalLinkage, EmLongjmpFName, &M);
+
+    // Only traverse functions that uses setjmp in order not to insert
+    // unnecessary prep / cleanup code in every function
+    SmallPtrSet<Function *, 8> SetjmpUsers;
+    for (User *U : SetjmpF->users()) {
+      auto *UI = cast<Instruction>(U);
+      SetjmpUsers.insert(UI->getFunction());
     }
+    for (Function *F : SetjmpUsers)
+      runSjLjOnFunction(*F);
   }
 
-  if (!Changed)
+  if (!Changed) {
+    // Delete unused global variables and functions
+    ThrewGV->eraseFromParent();
+    ThrewValueGV->eraseFromParent();
+    TempRet0GV->eraseFromParent();
+    if (ResumeF)
+      ResumeF->eraseFromParent();
+    if (EHTypeIDF)
+      EHTypeIDF->eraseFromParent();
+    if (EmLongjmpF)
+      EmLongjmpF->eraseFromParent();
+    if (SaveSetjmpF)
+      SaveSetjmpF->eraseFromParent();
+    if (TestSetjmpF)
+      TestSetjmpF->eraseFromParent();
     return false;
+  }
 
   // If we have made any changes while doing exception handling or
   // setjmp/longjmp handling, we have to create these functions for JavaScript
   // to call.
-  assert(!M.getNamedGlobal(SetThrewFName) && "setThrew already exists");
-  assert(!M.getNamedGlobal(SetTempRet0FName) && "setTempRet0 already exists");
-
-  // Create setThrew function
-  SmallVector<Type *, 2> Params = {Int1Ty, Int32Ty};
-  FunctionType *FTy = FunctionType::get(VoidTy, Params, false);
-  Function *F =
-      Function::Create(FTy, GlobalValue::ExternalLinkage, SetThrewFName, &M);
-  Argument *Arg1 = &*(F->arg_begin());
-  Argument *Arg2 = &*(++F->arg_begin());
-  Arg1->setName("threw");
-  Arg2->setName("value");
-  BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
-  BasicBlock *ThenBB = BasicBlock::Create(C, "if.then", F);
-  BasicBlock *EndBB = BasicBlock::Create(C, "if.end", F);
-
-  IRB.SetInsertPoint(EntryBB);
-  Value *Threw = IRB.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
-  Value *Cmp = IRB.CreateICmpEQ(Threw, IRB.getFalse(), "cmp");
-  IRB.CreateCondBr(Cmp, ThenBB, EndBB);
-
-  IRB.SetInsertPoint(ThenBB);
-  IRB.CreateStore(Arg1, ThrewGV);
-  IRB.CreateStore(Arg2, ThrewValueGV);
-  IRB.CreateBr(EndBB);
-
-  IRB.SetInsertPoint(EndBB);
-  IRB.CreateRetVoid();
-
-  // Create setTempRet0 function
-  Params = {Int32Ty};
-  FTy = FunctionType::get(VoidTy, Params, false);
-  F = Function::Create(FTy, GlobalValue::ExternalLinkage, SetTempRet0FName, &M);
-  F->arg_begin()->setName("value");
-  EntryBB = BasicBlock::Create(C, "entry", F);
-  IRB.SetInsertPoint(EntryBB);
-  IRB.CreateStore(&*F->arg_begin(), TempRet0GV);
-  IRB.CreateRetVoid();
+  createSetThrewFunction(M);
+  createSetTempRet0Function(M);
 
   return true;
 }
@@ -406,73 +832,19 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
 
     bool NeedInvoke = AllowExceptions && canThrow(II->getCalledValue());
     if (NeedInvoke) {
-      // 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(C, AttributeSet::FunctionIndex,
-                                 Attribute::NoReturn);
-        II->setAttributes(NewAttrs);
-      }
-
-      // Pre-invoke
-      // __THREW__ = 0;
-      IRB.CreateStore(IRB.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 = IRB.CreateCall(getInvokeWrapper(M, II), CallArgs);
-      NewCall->takeName(II);
-      NewCall->setCallingConv(II->getCallingConv());
-      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(C, i + 1, B));
-        }
-      }
-      // Add any return attributes.
-      if (InvokePAL.hasAttributes(AttributeSet::ReturnIndex))
-        AttributesVec.push_back(
-            AttributeSet::get(C, InvokePAL.getRetAttributes()));
-      // Add any function attributes.
-      if (InvokePAL.hasAttributes(AttributeSet::FunctionIndex))
-        AttributesVec.push_back(
-            AttributeSet::get(C, InvokePAL.getFnAttributes()));
-      // Reconstruct the AttributesList based on the vector we constructed.
-      AttributeSet NewCallPAL = AttributeSet::get(C, AttributesVec);
-      NewCall->setAttributes(NewCallPAL);
-
-      II->replaceAllUsesWith(NewCall);
+      // Wrap invoke with invoke wrapper and generate preamble/postamble
+      Value *Threw = wrapInvoke(II);
       ToErase.push_back(II);
 
-      // Post-invoke
-      // %__THREW__.val = __THREW__; __THREW__ = 0;
-      Value *Threw = IRB.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
-      IRB.CreateStore(IRB.getFalse(), ThrewGV);
-
       // Insert a branch based on __THREW__ variable
-      IRB.CreateCondBr(Threw, II->getUnwindDest(), II->getNormalDest());
+      Value *Cmp = IRB.CreateICmpEQ(Threw, IRB.getInt32(1), "cmp");
+      IRB.CreateCondBr(Cmp, 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 = IRB.CreateCall(II->getCalledValue(), CallArgs);
+      SmallVector<Value *, 16> Args(II->arg_begin(), II->arg_end());
+      CallInst *NewCall = IRB.CreateCall(II->getCalledValue(), Args);
       NewCall->takeName(II);
       NewCall->setCallingConv(II->getCallingConv());
       NewCall->setDebugLoc(II->getDebugLoc());
@@ -499,11 +871,8 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
       Value *Input = RI->getValue();
       IRB.SetInsertPoint(RI);
       Value *Low = IRB.CreateExtractValue(Input, 0, "low");
-
       // Create a call to __resumeException function
-      Value *Args[] = {Low};
-      IRB.CreateCall(ResumeF, Args);
-
+      IRB.CreateCall(ResumeF, {Low});
       // Add a terminator to the block
       IRB.CreateUnreachable();
       ToErase.push_back(RI);
@@ -548,7 +917,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
       // in the interface between JS and wasm, break out filter operands into
       // their component elements.
       if (LPI->isFilter(i)) {
-        ArrayType *ATy = cast<ArrayType>(Clause->getType());
+        auto *ATy = cast<ArrayType>(Clause->getType());
         for (unsigned j = 0, e = ATy->getNumElements(); j < e; ++j) {
           Value *EV = IRB.CreateExtractValue(Clause, makeArrayRef(j), "filter");
           FMCArgs.push_back(EV);
@@ -562,7 +931,8 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
     CallInst *FMCI = IRB.CreateCall(FMCF, FMCArgs, "fmc");
     Value *Undef = UndefValue::get(LPI->getType());
     Value *Pair0 = IRB.CreateInsertValue(Undef, FMCI, 0, "pair0");
-    Value *TempRet0 = IRB.CreateLoad(TempRet0GV, TempRet0GV->getName() + "val");
+    Value *TempRet0 =
+        IRB.CreateLoad(TempRet0GV, TempRet0GV->getName() + ".val");
     Value *Pair1 = IRB.CreateInsertValue(Pair0, TempRet0, 1, "pair1");
 
     LPI->replaceAllUsesWith(Pair1);
@@ -577,6 +947,235 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
 }
 
 bool WebAssemblyLowerEmscriptenEHSjLj::runSjLjOnFunction(Function &F) {
-  // TODO
-  return false;
+  Module &M = *F.getParent();
+  LLVMContext &C = F.getContext();
+  IRBuilder<> IRB(C);
+  SmallVector<Instruction *, 64> ToErase;
+  // Vector of %setjmpTable values
+  std::vector<Instruction *> SetjmpTableInsts;
+  // Vector of %setjmpTableSize values
+  std::vector<Instruction *> SetjmpTableSizeInsts;
+
+  // Setjmp preparation
+
+  // This instruction effectively means %setjmpTableSize = 4.
+  // We create this as an instruction intentionally, and we don't want to fold
+  // this instruction to a constant 4, because this value will be used in
+  // SSAUpdater.AddAvailableValue(...) later.
+  BasicBlock &EntryBB = F.getEntryBlock();
+  BinaryOperator *SetjmpTableSize = BinaryOperator::Create(
+      Instruction::Add, IRB.getInt32(4), IRB.getInt32(0), "setjmpTableSize",
+      &*EntryBB.getFirstInsertionPt());
+  // setjmpTable = (int *) malloc(40);
+  Instruction *SetjmpTable = CallInst::CreateMalloc(
+      SetjmpTableSize, IRB.getInt32Ty(), IRB.getInt32Ty(), IRB.getInt32(40),
+      nullptr, nullptr, "setjmpTable");
+  // setjmpTable[0] = 0;
+  IRB.SetInsertPoint(SetjmpTableSize);
+  IRB.CreateStore(IRB.getInt32(0), SetjmpTable);
+  SetjmpTableInsts.push_back(SetjmpTable);
+  SetjmpTableSizeInsts.push_back(SetjmpTableSize);
+
+  // Setjmp transformation
+  std::vector<PHINode *> SetjmpRetPHIs;
+  Function *SetjmpF = M.getFunction("setjmp");
+  for (User *U : SetjmpF->users()) {
+    auto *CI = dyn_cast<CallInst>(U);
+    if (!CI)
+      report_fatal_error("Does not support indirect calls to setjmp");
+
+    BasicBlock *BB = CI->getParent();
+    if (BB->getParent() != &F) // in other function
+      continue;
+
+    // The tail is everything right after the call, and will be reached once
+    // when setjmp is called, and later when longjmp returns to the setjmp
+    BasicBlock *Tail = SplitBlock(BB, CI->getNextNode());
+    // Add a phi to the tail, which will be the output of setjmp, which
+    // indicates if this is the first call or a longjmp back. The phi directly
+    // uses the right value based on where we arrive from
+    IRB.SetInsertPoint(Tail->getFirstNonPHI());
+    PHINode *SetjmpRet = IRB.CreatePHI(IRB.getInt32Ty(), 2, "setjmp.ret");
+
+    // setjmp initial call returns 0
+    SetjmpRet->addIncoming(IRB.getInt32(0), BB);
+    // The proper output is now this, not the setjmp call itself
+    CI->replaceAllUsesWith(SetjmpRet);
+    // longjmp returns to the setjmp will add themselves to this phi
+    SetjmpRetPHIs.push_back(SetjmpRet);
+
+    // Fix call target
+    // Our index in the function is our place in the array + 1 to avoid index
+    // 0, because index 0 means the longjmp is not ours to handle.
+    IRB.SetInsertPoint(CI);
+    Value *Args[] = {CI->getArgOperand(0), IRB.getInt32(SetjmpRetPHIs.size()),
+                     SetjmpTable, SetjmpTableSize};
+    Instruction *NewSetjmpTable =
+        IRB.CreateCall(SaveSetjmpF, Args, "setjmpTable");
+    Instruction *NewSetjmpTableSize =
+        IRB.CreateLoad(TempRet0GV, "setjmpTableSize");
+    SetjmpTableInsts.push_back(NewSetjmpTable);
+    SetjmpTableSizeInsts.push_back(NewSetjmpTableSize);
+    ToErase.push_back(CI);
+  }
+
+  // Update each call that can longjmp so it can return to a setjmp where
+  // relevant.
+
+  // Because we are creating new BBs while processing and don't want to make
+  // all these newly created BBs candidates again for longjmp processing, we
+  // first make the vector of candidate BBs.
+  std::vector<BasicBlock *> BBs;
+  for (BasicBlock &BB : F)
+    BBs.push_back(&BB);
+
+  // BBs.size() will change within the loop, so we query it every time
+  for (unsigned i = 0; i < BBs.size(); i++) {
+    BasicBlock *BB = BBs[i];
+    for (Instruction &I : *BB) {
+      assert(!isa<InvokeInst>(&I));
+      auto *CI = dyn_cast<CallInst>(&I);
+      if (!CI)
+        continue;
+
+      const Value *Callee = CI->getCalledValue();
+      if (!canLongjmp(M, Callee))
+        continue;
+
+      Value *Threw = nullptr;
+      BasicBlock *Tail;
+      if (Callee->getName().startswith(InvokePrefix)) {
+        // If invoke wrapper has already been generated for this call in
+        // previous EH phase, search for the load instruction
+        // %__THREW__.val = __THREW__;
+        // in postamble after the invoke wrapper call
+        LoadInst *ThrewLI = nullptr;
+        StoreInst *ThrewResetSI = nullptr;
+        for (auto I = std::next(BasicBlock::iterator(CI)), IE = BB->end();
+             I != IE; ++I) {
+          if (auto *LI = dyn_cast<LoadInst>(I))
+            if (auto *GV = dyn_cast<GlobalVariable>(LI->getPointerOperand()))
+              if (GV == ThrewGV) {
+                Threw = ThrewLI = LI;
+                break;
+              }
+        }
+        // Search for the store instruction after the load above
+        // __THREW__ = 0;
+        for (auto I = std::next(BasicBlock::iterator(ThrewLI)), IE = BB->end();
+             I != IE; ++I) {
+          if (auto *SI = dyn_cast<StoreInst>(I))
+            if (auto *GV = dyn_cast<GlobalVariable>(SI->getPointerOperand()))
+              if (GV == ThrewGV && SI->getValueOperand() == IRB.getInt32(0)) {
+                ThrewResetSI = SI;
+                break;
+              }
+        }
+        assert(Threw && ThrewLI && "Cannot find __THREW__ load after invoke");
+        assert(ThrewResetSI && "Cannot find __THREW__ store after invoke");
+        Tail = SplitBlock(BB, ThrewResetSI->getNextNode());
+
+      } else {
+        // Wrap call with invoke wrapper and generate preamble/postamble
+        Threw = wrapInvoke(CI);
+        ToErase.push_back(CI);
+        Tail = SplitBlock(BB, CI->getNextNode());
+      }
+
+      // We need to replace the terminator in Tail - SplitBlock makes BB go
+      // straight to Tail, we need to check if a longjmp occurred, and go to the
+      // right setjmp-tail if so
+      ToErase.push_back(BB->getTerminator());
+
+      // Generate a function call to testSetjmp function and preamble/postamble
+      // code to figure out (1) whether longjmp occurred (2) if longjmp
+      // occurred, which setjmp it corresponds to
+      Value *Label = nullptr;
+      Value *LongjmpResult = nullptr;
+      BasicBlock *EndBB = nullptr;
+      wrapTestSetjmp(BB, CI, Threw, SetjmpTable, SetjmpTableSize, Label,
+                     LongjmpResult, EndBB);
+      assert(Label && LongjmpResult && EndBB);
+
+      // Create switch instruction
+      IRB.SetInsertPoint(EndBB);
+      SwitchInst *SI = IRB.CreateSwitch(Label, Tail, SetjmpRetPHIs.size());
+      // -1 means no longjmp happened, continue normally (will hit the default
+      // switch case). 0 means a longjmp that is not ours to handle, needs a
+      // rethrow. Otherwise the index is the same as the index in P+1 (to avoid
+      // 0).
+      for (unsigned i = 0; i < SetjmpRetPHIs.size(); i++) {
+        SI->addCase(IRB.getInt32(i + 1), SetjmpRetPHIs[i]->getParent());
+        SetjmpRetPHIs[i]->addIncoming(LongjmpResult, EndBB);
+      }
+
+      // We are splitting the block here, and must continue to find other calls
+      // in the block - which is now split. so continue to traverse in the Tail
+      BBs.push_back(Tail);
+    }
+  }
+
+  // Erase everything we no longer need in this function
+  for (Instruction *I : ToErase)
+    I->eraseFromParent();
+
+  // Free setjmpTable buffer before each return instruction
+  for (BasicBlock &BB : F) {
+    TerminatorInst *TI = BB.getTerminator();
+    if (isa<ReturnInst>(TI))
+      CallInst::CreateFree(SetjmpTable, TI);
+  }
+
+  // Every call to saveSetjmp can change setjmpTable and setjmpTableSize
+  // (when buffer reallocation occurs)
+  // entry:
+  //   setjmpTableSize = 4;
+  //   setjmpTable = (int *) malloc(40);
+  //   setjmpTable[0] = 0;
+  // ...
+  // somebb:
+  //   setjmpTable = saveSetjmp(buf, label, setjmpTable, setjmpTableSize);
+  //   setjmpTableSize = __tempRet0;
+  // So we need to make sure the SSA for these variables is valid so that every
+  // saveSetjmp and testSetjmp calls have the correct arguments.
+  SSAUpdater SetjmpTableSSA;
+  SSAUpdater SetjmpTableSizeSSA;
+  SetjmpTableSSA.Initialize(Type::getInt32PtrTy(C), "setjmpTable");
+  SetjmpTableSizeSSA.Initialize(Type::getInt32Ty(C), "setjmpTableSize");
+  for (Instruction *I : SetjmpTableInsts)
+    SetjmpTableSSA.AddAvailableValue(I->getParent(), I);
+  for (Instruction *I : SetjmpTableSizeInsts)
+    SetjmpTableSizeSSA.AddAvailableValue(I->getParent(), I);
+
+  for (auto UI = SetjmpTable->use_begin(), UE = SetjmpTable->use_end();
+       UI != UE;) {
+    // Grab the use before incrementing the iterator.
+    Use &U = *UI;
+    // Increment the iterator before removing the use from the list.
+    ++UI;
+    if (Instruction *I = dyn_cast<Instruction>(U.getUser()))
+      if (I->getParent() != &EntryBB)
+        SetjmpTableSSA.RewriteUse(U);
+  }
+  for (auto UI = SetjmpTableSize->use_begin(), UE = SetjmpTableSize->use_end();
+       UI != UE;) {
+    Use &U = *UI;
+    ++UI;
+    if (Instruction *I = dyn_cast<Instruction>(U.getUser()))
+      if (I->getParent() != &EntryBB)
+        SetjmpTableSizeSSA.RewriteUse(U);
+  }
+
+  // Finally, our modifications to the cfg can break dominance of SSA variables.
+  // For example, in this code,
+  // if (x()) { .. setjmp() .. }
+  // if (y()) { .. longjmp() .. }
+  // We must split the longjmp block, and it can jump into the block splitted
+  // from setjmp one. But that means that when we split the setjmp block, it's
+  // first part no longer dominates its second part - there is a theoretically
+  // possible control flow path where x() is false, then y() is true and we
+  // reach the second part of the setjmp block, without ever reaching the first
+  // part. So, we rebuild SSA form here.
+  rebuildSSA(F);
+  return true;
 }

Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp?rev=280302&r1=280301&r2=280302&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp Wed Aug 31 17:40:34 2016
@@ -165,7 +165,14 @@ void WebAssemblyPassConfig::addIRPasses(
   if (getOptLevel() != CodeGenOpt::None)
     addPass(createWebAssemblyOptimizeReturned());
 
-  // Handle exceptions.
+  // If exception handling is not enabled, we lower invokes into calls and
+  // simplify CFG to delete unreachable landingpad blocks.
+  if (!EnableEmException) {
+    addPass(createLowerInvokePass());
+    addPass(createCFGSimplificationPass());
+  }
+
+  // Handle exceptions and setjmp/longjmp if enabled.
   if (EnableEmException || EnableEmSjLj)
     addPass(createWebAssemblyLowerEmscriptenEHSjLj(EnableEmException,
                                                    EnableEmSjLj));

Added: llvm/trunk/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll?rev=280302&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll (added)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll Wed Aug 31 17:40:34 2016
@@ -0,0 +1,61 @@
+; RUN: llc < %s -enable-emscripten-cxx-exceptions | FileCheck %s --check-prefix=EH
+; RUN: llc < %s -enable-emscripten-sjlj | FileCheck %s --check-prefix=SJLJ
+; RUN: llc < %s | FileCheck %s --check-prefix=NONE
+
+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] }
+
+define hidden void @exception() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; EH-LABEL:   type exception, at function
+; NONE-LABEL: type exception, at function
+entry:
+  invoke void @foo()
+          to label %try.cont unwind label %lpad
+; EH:   call __invoke_void at FUNCTION
+; NONE: call foo at FUNCTION
+
+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
+}
+
+define hidden void @setjmp_longjmp() {
+; SJLJ-LABEL: type setjmp_longjmp, at function
+; NONE-LABEL: type setjmp_longjmp, at function
+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
+  %arraydecay1 = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
+  call void @longjmp(%struct.__jmp_buf_tag* %arraydecay1, i32 1) #1
+  unreachable
+; SJLJ: i32.call ${{[a-zA-Z0-9]+}}=, saveSetjmp at FUNCTION
+; SJLJ: i32.call ${{[a-zA-Z0-9]+}}=, testSetjmp at FUNCTION
+; NONE: i32.call ${{[a-zA-Z0-9]+}}=, setjmp at FUNCTION
+; NONE: call longjmp at FUNCTION
+}
+
+declare void @foo()
+declare i32 @__gxx_personality_v0(...)
+declare i8* @__cxa_begin_catch(i8*)
+declare void @__cxa_end_catch()
+; Function Attrs: returns_twice
+declare i32 @setjmp(%struct.__jmp_buf_tag*) #0
+; Function Attrs: noreturn
+declare void @longjmp(%struct.__jmp_buf_tag*, i32) #1
+declare i8* @malloc(i32)
+declare void @free(i8*)
+
+attributes #0 = { returns_twice }
+attributes #1 = { noreturn }
+attributes #2 = { nounwind }

Modified: llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions-whitelist.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions-whitelist.ll?rev=280302&r1=280301&r2=280302&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions-whitelist.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions-whitelist.ll Wed Aug 31 17:40:34 2016
@@ -1,5 +1,8 @@
 ; RUN: opt < %s -wasm-lower-em-ehsjlj -emscripten-cxx-exceptions-whitelist=do_catch -S | FileCheck %s
 
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
 define void @dont_catch() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
 ; CHECK-LABEL: @dont_catch(
 entry:
@@ -34,7 +37,7 @@ entry:
   invoke void @foo()
           to label %invoke.cont unwind label %lpad
 ; CHECK: entry:
-; CHECK-NEXT: store i1 false, i1*
+; CHECK-NEXT: store i32 0, i32*
 ; CHECK-NEXT: call void @__invoke_void(void ()* @foo)
 
 invoke.cont:                                      ; preds = %entry

Modified: llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll?rev=280302&r1=280301&r2=280302&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll Wed Aug 31 17:40:34 2016
@@ -1,10 +1,13 @@
 ; RUN: opt < %s -wasm-lower-em-ehsjlj -S | FileCheck %s
 
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
 @_ZTIi = external constant i8*
 @_ZTIc = external constant i8*
-; CHECK: @[[__THREW__:__THREW__.*]] = global i1 false
-; CHECK: @[[THREWVALUE:__threwValue.*]] = global i32 0
-; CHECK: @[[TEMPRET0:__tempRet0.*]] = global i32 0
+; CHECK-DAG: @[[__THREW__:__THREW__.*]] = global i32 0
+; CHECK-DAG: @[[THREWVALUE:__threwValue.*]] = global i32 0
+; CHECK-DAG: @[[TEMPRET0:__tempRet0.*]] = global i32 0
 
 ; Test invoke instruction with clauses (try-catch block)
 define void @clause() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
@@ -13,11 +16,12 @@ entry:
   invoke void @foo(i32 3)
           to label %invoke.cont unwind label %lpad
 ; CHECK: entry:
-; CHECK-NEXT: store i1 false, i1* @[[__THREW__]]
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
 ; CHECK-NEXT: call void @__invoke_void_i32(void (i32)* @foo, i32 3)
-; CHECK-NEXT: %[[__THREW__VAL:.*]] = load i1, i1* @[[__THREW__]]
-; CHECK-NEXT: store i1 false, i1* @[[__THREW__]]
-; CHECK-NEXT: br i1 %[[__THREW__VAL]], label %lpad, label %invoke.cont
+; CHECK-NEXT: %[[__THREW__VAL:.*]] = load i32, i32* @[[__THREW__]]
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
+; CHECK-NEXT: %cmp = icmp eq i32 %[[__THREW__VAL]], 1
+; CHECK-NEXT: br i1 %cmp, label %lpad, label %invoke.cont
 
 invoke.cont:                                      ; preds = %entry
   br label %try.cont
@@ -68,11 +72,12 @@ entry:
   invoke void @foo(i32 3)
           to label %invoke.cont unwind label %lpad
 ; CHECK: entry:
-; CHECK-NEXT: store i1 false, i1* @[[__THREW__]]
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
 ; CHECK-NEXT: call void @__invoke_void_i32(void (i32)* @foo, i32 3)
-; CHECK-NEXT: %[[__THREW__VAL:.*]] = load i1, i1* @[[__THREW__]]
-; CHECK-NEXT: store i1 false, i1* @[[__THREW__]]
-; CHECK-NEXT: br i1 %[[__THREW__VAL]], label %lpad, label %invoke.cont
+; CHECK-NEXT: %[[__THREW__VAL:.*]] = load i32, i32* @[[__THREW__]]
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
+; CHECK-NEXT: %cmp = icmp eq i32 %[[__THREW__VAL]], 1
+; CHECK-NEXT: br i1 %cmp, label %lpad, label %invoke.cont
 
 invoke.cont:                                      ; preds = %entry
   ret void
@@ -118,7 +123,7 @@ 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: store i32 0, i32* @[[__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
@@ -162,19 +167,19 @@ 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 @__invoke_void_i32(void (i32)*, i32)
-; CHECK: declare i8* @__cxa_find_matching_catch_4(i8*, i8*)
+; JS glue functions and invoke wrappers declaration
+; CHECK-DAG: declare void @__resumeException(i8*)
+; CHECK-DAG: declare void @__invoke_void_i32(void (i32)*, i32)
+; CHECK-DAG: declare i8* @__cxa_find_matching_catch_4(i8*, i8*)
 
 ; setThrew function creation
-; CHECK-LABEL: define void @setThrew(i1 %threw, i32 %value) {
+; CHECK-LABEL: define void @setThrew(i32 %threw, i32 %value) {
 ; CHECK: entry:
-; CHECK-NEXT: %[[__THREW__]].val = load i1, i1* @[[__THREW__]]
-; CHECK-NEXT: %cmp = icmp eq i1 %[[__THREW__]].val, false
+; CHECK-NEXT: %[[__THREW__]].val = load i32, i32* @[[__THREW__]]
+; CHECK-NEXT: %cmp = icmp eq i32 %[[__THREW__]].val, 0
 ; CHECK-NEXT: br i1 %cmp, label %if.then, label %if.end
 ; CHECK: if.then:
-; CHECK-NEXT: store i1 %threw, i1* @[[__THREW__]]
+; CHECK-NEXT: store i32 %threw, i32* @[[__THREW__]]
 ; CHECK-NEXT: store i32 %value, i32* @[[THREWVALUE]]
 ; CHECK-NEXT: br label %if.end
 ; CHECK: if.end:

Added: llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll?rev=280302&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll (added)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll Wed Aug 31 17:40:34 2016
@@ -0,0 +1,213 @@
+; RUN: opt < %s -wasm-lower-em-ehsjlj -S | FileCheck %s
+
+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] }
+
+ at global_var = hidden global i32 0, align 4
+; CHECK-DAG: @[[__THREW__:__THREW__.*]] = global i32 0
+; CHECK-DAG: @[[THREWVALUE:__threwValue.*]] = global i32 0
+; CHECK-DAG: @[[TEMPRET0:__tempRet0.*]] = global i32 0
+
+; Test a simple setjmp - longjmp sequence
+define hidden void @setjmp_longjmp() {
+; CHECK-LABEL: @setjmp_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
+  %arraydecay1 = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
+  call void @longjmp(%struct.__jmp_buf_tag* %arraydecay1, i32 1) #1
+  unreachable
+; CHECK: entry:
+; CHECK-NEXT: %[[MALLOCCALL:.*]] = tail call i8* @malloc(i32 40)
+; CHECK-NEXT: %[[SETJMP_TABLE:.*]] = bitcast i8* %[[MALLOCCALL]] to i32*
+; CHECK-NEXT: store i32 0, i32* %[[SETJMP_TABLE]]
+; CHECK-NEXT: %[[SETJMP_TABLE_SIZE:.*]] = add i32 4, 0
+; CHECK-NEXT: %[[BUF:.*]] = alloca [1 x %struct.__jmp_buf_tag]
+; CHECK-NEXT: %[[ARRAYDECAY:.*]] = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %[[BUF]], i32 0, i32 0
+; CHECK-NEXT: %[[SETJMP_TABLE1:.*]] = call i32* @saveSetjmp(%struct.__jmp_buf_tag* %[[ARRAYDECAY]], i32 1, i32* %[[SETJMP_TABLE]], i32 %[[SETJMP_TABLE_SIZE]])
+; CHECK-NEXT: %[[SETJMP_TABLE_SIZE1:.*]] = load i32, i32* @[[TEMPRET0]]
+; CHECK-NEXT: br label %entry.split
+
+; CHECK: entry.split:
+; CHECK-NEXT: phi i32 [ 0, %entry ], [ %[[LONGJMP_RESULT:.*]], %if.end ]
+; CHECK-NEXT: %[[ARRAYDECAY1:.*]] = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %[[BUF]], i32 0, i32 0
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
+; CHECK-NEXT: call void @"__invoke_void_%struct.__jmp_buf_tag*_i32"(void (%struct.__jmp_buf_tag*, i32)* @emscripten_longjmp_jmpbuf, %struct.__jmp_buf_tag* %[[ARRAYDECAY1]], i32 1)
+; CHECK-NEXT: %[[__THREW__VAL:.*]] = load i32, i32* @[[__THREW__]]
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
+; CHECK-NEXT: %[[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
+
+; CHECK: entry.split.split:
+; CHECK-NEXT: unreachable
+
+; CHECK: if.then1:
+; CHECK-NEXT: %[[__THREW__VAL_I32P:.*]] = inttoptr i32 %[[__THREW__VAL]] to i32*
+; CHECK-NEXT: %[[__THREW__VAL_I32P_LOADED:.*]] = load i32, i32* %[[__THREW__VAL_I32P]]
+; CHECK-NEXT: %[[LABEL:.*]] = call i32 @testSetjmp(i32 %[[__THREW__VAL_I32P_LOADED]], i32* %[[SETJMP_TABLE1]], i32 %[[SETJMP_TABLE_SIZE1]])
+; CHECK-NEXT: %[[CMP:.*]] = icmp eq i32 %[[LABEL]], 0
+; CHECK-NEXT: br i1 %[[CMP]], label %if.then2, label %if.end2
+
+; CHECK: if.else1:
+; CHECK-NEXT: br label %if.end
+
+; CHECK: if.end:
+; CHECK-NEXT: %[[LABEL_PHI:.*]] = phi i32 [ %[[LABEL:.*]], %if.end2 ], [ -1, %if.else1 ]
+; CHECK-NEXT: %[[LONGJMP_RESULT]] = load i32, i32* @[[TEMPRET0]]
+; CHECK-NEXT: switch i32 %[[LABEL_PHI]], label %entry.split.split [
+; CHECK-NEXT:   i32 1, label %entry.split
+; CHECK-NEXT: ]
+
+; CHECK: if.then2:
+; CHECK-NEXT: call void @emscripten_longjmp(i32 %[[__THREW__VAL]], i32 %[[THREWVALUE_VAL]])
+; CHECK-NEXT: unreachable
+
+; CHECK: if.end2:
+; CHECK-NEXT: store i32 %[[THREWVALUE_VAL]], i32* @[[TEMPRET0]]
+; CHECK-NEXT: br label %if.end
+}
+
+; Test a case of a function call (which is not longjmp) after a setjmp
+define hidden void @setjmp_other() {
+; CHECK-LABEL: @setjmp_other
+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
+  call void @foo()
+  ret void
+; CHECK: entry:
+; CHECK: %[[SETJMP_TABLE:.*]] = call i32* @saveSetjmp(
+
+; CHECK: entry.split:
+; CHECK: call void @__invoke_void(void ()* @foo)
+
+; CHECK: entry.split.split:
+; CHECK-NEXT: %[[BUF:.*]] = bitcast i32* %[[SETJMP_TABLE]] to i8*
+; CHECK-NEXT: tail call void @free(i8* %[[BUF]])
+; CHECK-NEXT: ret void
+}
+
+; Test a case when a function call is within try-catch, after a setjmp
+define hidden void @exception_and_longjmp() #3 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 i32 0, i32* @[[__THREW__]]
+; CHECK-NEXT: call void @__invoke_void(void ()* @foo)
+; CHECK-NEXT: %[[__THREW__VAL:.*]] = load i32, i32* @[[__THREW__]]
+; CHECK-NEXT: store i32 0, i32* @[[__THREW__]]
+; CHECK-NEXT: %[[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
+
+; CHECK: entry.split.split:
+; CHECK-NEXT: %[[CMP:.*]] = icmp eq i32 %[[__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 hidden void @ssa(i32 %n) {
+; CHECK-LABEL: @ssa
+entry:
+  %buf = alloca [1 x %struct.__jmp_buf_tag], align 16
+  %cmp = icmp sgt i32 %n, 5
+  br i1 %cmp, label %if.then, label %if.end
+; CHECK: entry:
+; CHECK: %[[SETJMP_TABLE0:.*]] = bitcast i8*
+; CHECK: %[[SETJMP_TABLE_SIZE0:.*]] = add i32 4, 0
+
+if.then:                                          ; preds = %entry
+  %0 = load i32, i32* @global_var, align 4
+  %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
+  store i32 %0, i32* @global_var, align 4
+  br label %if.end
+; CHECK: if.then:
+; CHECK: %[[VAR0:.*]] = load i32, i32* @global_var, align 4
+; CHECK: %[[SETJMP_TABLE1:.*]] = call i32* @saveSetjmp(
+; CHECK-NEXT: %[[SETJMP_TABLE_SIZE1:.*]] = load i32, i32* @[[TEMPRET0]]
+
+; CHECK: if.then.split:
+; CHECK: %[[VAR1:.*]] = phi i32 [ %[[VAR0]], %if.then ], [ %[[VAR2:.*]], %if.end3 ]
+; CHECK: %[[SETJMP_TABLE_SIZE2:.*]] = phi i32 [ %[[SETJMP_TABLE_SIZE1]], %if.then ], [ %[[SETJMP_TABLE_SIZE3:.*]], %if.end3 ]
+; CHECK: %[[SETJMP_TABLE2:.*]] = phi i32* [ %[[SETJMP_TABLE1]], %if.then ], [ %[[SETJMP_TABLE3:.*]], %if.end3 ]
+; CHECK: store i32 %[[VAR1]], i32* @global_var, align 4
+
+if.end:                                           ; preds = %if.then, %entry
+  %arraydecay1 = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
+  call void @longjmp(%struct.__jmp_buf_tag* %arraydecay1, i32 5) #1
+  unreachable
+; CHECK: if.end:
+; CHECK: %[[VAR2]] = phi i32 [ %[[VAR1]], %if.then.split ], [ undef, %entry ]
+; CHECK: %[[SETJMP_TABLE_SIZE3]] = phi i32 [ %[[SETJMP_TABLE_SIZE2]], %if.then.split ], [ %[[SETJMP_TABLE_SIZE0]], %entry ]
+; CHECK: %[[SETJMP_TABLE3]] = phi i32* [ %[[SETJMP_TABLE2]], %if.then.split ], [ %[[SETJMP_TABLE0]], %entry ]
+}
+
+; Test a case when a function only calls other functions that are neither setjmp nor longjmp
+define hidden void @only_other_func() {
+entry:
+  call void @foo()
+  ret void
+; CHECK: call void @foo()
+}
+
+; Test a case when a function only calls longjmp and not setjmp
+define hidden void @only_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 void @longjmp(%struct.__jmp_buf_tag* %arraydecay, i32 5) #1
+  unreachable
+; CHECK: %[[ARRAYDECAY:.*]] = getelementptr inbounds
+; CHECK-NEXT: call void @emscripten_longjmp_jmpbuf(%struct.__jmp_buf_tag* %[[ARRAYDECAY]], i32 5) #1
+}
+
+declare void @foo()
+; Function Attrs: returns_twice
+declare i32 @setjmp(%struct.__jmp_buf_tag*) #0
+; Function Attrs: noreturn
+declare void @longjmp(%struct.__jmp_buf_tag*, i32) #1
+declare i32 @__gxx_personality_v0(...)
+declare i8* @__cxa_begin_catch(i8*)
+declare void @__cxa_end_catch()
+declare i8* @malloc(i32)
+declare void @free(i8*)
+
+; JS glue functions and invoke wrappers declaration
+; CHECK-DAG: declare i32* @saveSetjmp(%struct.__jmp_buf_tag*, i32, i32*, i32)
+; CHECK-DAG: declare i32 @testSetjmp(i32, i32*, i32)
+; CHECK-DAG: declare void @emscripten_longjmp_jmpbuf(%struct.__jmp_buf_tag*, i32)
+; CHECK-DAG: declare void @emscripten_longjmp(i32, i32)
+; CHECK-DAG: declare void @__invoke_void(void ()*)
+; CHECK-DAG: declare void @"__invoke_void_%struct.__jmp_buf_tag*_i32"(void (%struct.__jmp_buf_tag*, i32)*, %struct.__jmp_buf_tag*, i32)
+
+attributes #0 = { returns_twice }
+attributes #1 = { noreturn }
+attributes #2 = { nounwind }




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