diff --git a/patches/llvm/11.0.0/001-hardware-exception-handling.patch b/patches/llvm/11.0.0/001-hardware-exception-handling.patch
new file mode 100644
index 0000000..b7fdd5c
--- /dev/null
+++ b/patches/llvm/11.0.0/001-hardware-exception-handling.patch
@@ -0,0 +1,601 @@
+diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
+index d3fad58fcf5..dccbbe2fade 100644
+--- a/clang/include/clang/AST/Stmt.h
++++ b/clang/include/clang/AST/Stmt.h
+@@ -1764,6 +1764,7 @@ public:
+ class LabelStmt : public ValueStmt {
+ LabelDecl *TheDecl;
+ Stmt *SubStmt;
++ bool SideEntry = false;
+
+ public:
+ /// Build a label statement.
+@@ -1799,6 +1800,9 @@ public:
+ static bool classof(const Stmt *T) {
+ return T->getStmtClass() == LabelStmtClass;
+ }
++
++ bool isSideEntry() const { return SideEntry; }
++ void setSideEntry() { SideEntry = true; }
+ };
+
+ /// Represents an attribute applied to a statement.
+diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
+index 70f68d664bb..1e87b455db8 100644
+--- a/clang/include/clang/Basic/LangOptions.def
++++ b/clang/include/clang/Basic/LangOptions.def
+@@ -128,6 +128,7 @@ LANGOPT(ZVector , 1, 0, "System z vector extensions")
+ LANGOPT(Exceptions , 1, 0, "exception handling")
+ LANGOPT(ObjCExceptions , 1, 0, "Objective-C exceptions")
+ LANGOPT(CXXExceptions , 1, 0, "C++ exceptions")
++LANGOPT(EHAsynch , 1, 0, "C/C++ EH Asynch exceptions")
+ LANGOPT(DWARFExceptions , 1, 0, "dwarf exception handling")
+ LANGOPT(SjLjExceptions , 1, 0, "setjmp-longjump exception handling")
+ LANGOPT(SEHExceptions , 1, 0, "SEH .xdata exception handling")
+diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
+index 966cb907b7e..dc7b38c254f 100644
+--- a/clang/include/clang/Driver/Options.td
++++ b/clang/include/clang/Driver/Options.td
+@@ -889,6 +889,8 @@ def fno_crash_diagnostics : Flag<["-"], "fno-crash-diagnostics">, Group<f_clang_
+ def fcrash_diagnostics_dir : Joined<["-"], "fcrash-diagnostics-dir=">, Group<f_clang_Group>, Flags<[NoArgumentUnused, CoreOption]>;
+ def fcreate_profile : Flag<["-"], "fcreate-profile">, Group<f_Group>;
+ defm cxx_exceptions: OptInFFlag<"cxx-exceptions", "Enable C++ exceptions">;
++def feh_asynch: Flag<["-"], "feh-asynch">, Group<f_Group>,
++ HelpText<"Enable EH Asynchronous exceptions">, Flags<[CC1Option]>;
+ def fcxx_modules : Flag <["-"], "fcxx-modules">, Group<f_Group>,
+ Flags<[DriverOption]>;
+ def fdebug_pass_arguments : Flag<["-"], "fdebug-pass-arguments">, Group<f_Group>;
+@@ -1505,6 +1507,7 @@ def fno_common : Flag<["-"], "fno-common">, Group<f_Group>, Flags<[CC1Option]>,
+ def fno_constant_cfstrings : Flag<["-"], "fno-constant-cfstrings">, Group<f_Group>,
+ Flags<[CC1Option]>,
+ HelpText<"Disable creation of CodeFoundation-type constant strings">;
++def fno_eh_asynch: Flag<["-"], "fno-eh-asynch">, Group<f_Group>;
+ def fno_cxx_modules : Flag <["-"], "fno-cxx-modules">, Group<f_Group>,
+ Flags<[DriverOption]>;
+ def fno_diagnostics_fixit_info : Flag<["-"], "fno-diagnostics-fixit-info">, Group<f_Group>,
+diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
+index ad543ef86c1..7c1902f080f 100644
+--- a/clang/lib/CodeGen/CGCleanup.cpp
++++ b/clang/lib/CodeGen/CGCleanup.cpp
+@@ -763,10 +763,22 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
+ destroyOptimisticNormalEntry(*this, Scope);
+ EHStack.popCleanup();
+ } else {
++ // Under -EHa, invoke eha_scope_end() to mark scope end before dtor
++ bool IsEHa = getLangOpts().EHAsynch && !Scope.isLifetimeMarker();
++ const EHPersonality &Personality = EHPersonality::get(*this);
++
+ // If we have a fallthrough and no other need for the cleanup,
+ // emit it directly.
+- if (HasFallthrough && !HasPrebranchedFallthrough &&
+- !HasFixups && !HasExistingBranches) {
++ if (HasFallthrough && !HasPrebranchedFallthrough && !HasFixups &&
++ !HasExistingBranches) {
++
++ // mark EHa scope end for fall-through flow
++ if (IsEHa && getInvokeDest())
++ if (Personality.isMSVCXXPersonality())
++ EmitSehCppScopeEnd();
++ else {
++ EmitSehTryScopeEnd();
++ }
+
+ destroyOptimisticNormalEntry(*this, Scope);
+ EHStack.popCleanup();
+@@ -801,6 +813,14 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
+ // should already be branched to it.
+ EmitBlock(NormalEntry);
+
++ // intercept normal cleanup to mark EHa scope end
++ if (IsEHa)
++ if (Personality.isMSVCXXPersonality())
++ EmitSehCppScopeEnd();
++ else {
++ EmitSehTryScopeEnd();
++ }
++
+ // III. Figure out where we're going and build the cleanup
+ // epilogue.
+
+@@ -1276,3 +1296,61 @@ void CodeGenFunction::EmitCXXTemporary(const CXXTemporary *Temporary,
+ pushDestroy(NormalAndEHCleanup, Ptr, TempType, destroyCXXObject,
+ /*useEHCleanup*/ true);
+ }
++
++// Need to set "funclet" in OperandBundle properly for noThrow
++// intrinsic (see CGCall.cpp)
++static void EmitSehEHaScope(CodeGenFunction &CGF,
++ llvm::FunctionCallee &SehCppScope) {
++ llvm::BasicBlock *InvokeDest = CGF.getInvokeDest();
++ llvm::BasicBlock *BB = CGF.Builder.GetInsertBlock();
++ assert(BB && InvokeDest);
++ llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
++ SmallVector<llvm::OperandBundleDef, 1> BundleList =
++ CGF.getBundlesForFunclet(SehCppScope.getCallee());
++ if (CGF.CurrentFuncletPad)
++ BundleList.emplace_back("funclet", CGF.CurrentFuncletPad);
++ CGF.Builder.CreateInvoke(SehCppScope, Cont, InvokeDest, None, BundleList);
++ CGF.EmitBlock(Cont);
++}
++
++// Invoke a llvm.eha.scope.begin at the beginning of a CPP scope for -EHa
++void CodeGenFunction::EmitSehCppScopeBegin() {
++ assert(getLangOpts().EHAsynch);
++ llvm::FunctionType *FTy =
++ llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
++ llvm::FunctionCallee SehCppScope =
++ CGM.CreateRuntimeFunction(FTy, "llvm.eha.scope.begin");
++ EmitSehEHaScope(*this, SehCppScope);
++}
++
++// Invoke a llvm.eha.scope.end at the end of a CPP scope for -EHa
++// llvm.eha.scope.end is emitted before popCleanup, so it's "invoked"
++void CodeGenFunction::EmitSehCppScopeEnd() {
++ assert(getLangOpts().EHAsynch);
++ llvm::FunctionType *FTy =
++ llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
++ llvm::FunctionCallee SehCppScope =
++ CGM.CreateRuntimeFunction(FTy, "llvm.eha.scope.end");
++ EmitSehEHaScope(*this, SehCppScope);
++}
++
++// Invoke a llvm.eha.scope.begin at the beginning of a CPP scope for -EHa
++void CodeGenFunction::EmitSehTryScopeBegin() {
++ assert(getLangOpts().EHAsynch);
++ llvm::FunctionType *FTy =
++ llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
++ llvm::FunctionCallee SehCppScope =
++ CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.begin");
++ EmitSehEHaScope(*this, SehCppScope);
++}
++
++// Invoke a llvm.eha.scope.end at the end of a CPP scope for -EHa
++// llvm.eha.scope.end is emitted before popCleanup, so it's "invoked"
++void CodeGenFunction::EmitSehTryScopeEnd() {
++ assert(getLangOpts().EHAsynch);
++ llvm::FunctionType *FTy =
++ llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
++ llvm::FunctionCallee SehCppScope =
++ CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.end");
++ EmitSehEHaScope(*this, SehCppScope);
++}
+diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
+index 1729c7ed3c3..c9107b1296f 100644
+--- a/clang/lib/CodeGen/CGDecl.cpp
++++ b/clang/lib/CodeGen/CGDecl.cpp
+@@ -2006,9 +2006,16 @@ void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
+ const VarDecl &D = *emission.Variable;
+
+ // Check the type for a cleanup.
+- if (QualType::DestructionKind dtorKind = D.needsDestruction(getContext()))
++ if (QualType::DestructionKind dtorKind = D.needsDestruction(getContext())) {
+ emitAutoVarTypeCleanup(emission, dtorKind);
+
++ // Under -EHa, Invoke llvm.eha.scope.begin() right after
++ // Ctor is emitted and EHStack.pushCleanup
++ bool IsEHa = getLangOpts().EHAsynch;
++ if (IsEHa && dtorKind == QualType::DK_cxx_destructor)
++ EmitSehCppScopeBegin();
++ }
++
+ // In GC mode, honor objc_precise_lifetime.
+ if (getLangOpts().getGC() != LangOptions::NonGC &&
+ D.hasAttr<ObjCPreciseLifetimeAttr>()) {
+diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
+index bdf70252b5a..a4e4d7d8120 100644
+--- a/clang/lib/CodeGen/CGException.cpp
++++ b/clang/lib/CodeGen/CGException.cpp
+@@ -39,6 +39,18 @@ static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM) {
+ return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
+ }
+
++static llvm::FunctionCallee getSehTryBeginFn(CodeGenModule &CGM) {
++ llvm::FunctionType *FTy =
++ llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
++ return CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.begin");
++}
++
++static llvm::FunctionCallee getSehTryEndFn(CodeGenModule &CGM) {
++ llvm::FunctionType *FTy =
++ llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
++ return CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.end");
++}
++
+ static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM) {
+ // void __cxa_call_unexpected(void *thrown_exception);
+
+@@ -451,7 +463,7 @@ void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
+ if (!FD) {
+ // Check if CapturedDecl is nothrow and create terminate scope for it.
+ if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
+- if (CD->isNothrow())
++ if (CD->isNothrow() && !getLangOpts().EHAsynch /* !IsEHa */)
+ EHStack.pushTerminate();
+ }
+ return;
+@@ -463,7 +475,8 @@ void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
+ ExceptionSpecificationType EST = Proto->getExceptionSpecType();
+ if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
+ // noexcept functions are simple terminate scopes.
+- EHStack.pushTerminate();
++ if (!getLangOpts().EHAsynch) // -EHa: HW exception still can occur
++ EHStack.pushTerminate();
+ } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
+ // TODO: Revisit exception specifications for the MS ABI. There is a way to
+ // encode these in an object file but MSVC doesn't do anything with it.
+@@ -540,7 +553,7 @@ void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
+ if (!FD) {
+ // Check if CapturedDecl is nothrow and pop terminate scope for it.
+ if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
+- if (CD->isNothrow())
++ if (CD->isNothrow() && !EHStack.empty())
+ EHStack.popTerminate();
+ }
+ return;
+@@ -550,7 +563,8 @@ void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
+ return;
+
+ ExceptionSpecificationType EST = Proto->getExceptionSpecType();
+- if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
++ if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot &&
++ !EHStack.empty() /* possible empty when -EHa */) {
+ EHStack.popTerminate();
+ } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
+ // TODO: Revisit exception specifications for the MS ABI. There is a way to
+@@ -606,6 +620,9 @@ void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
+ } else {
+ // No exception decl indicates '...', a catch-all.
+ CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
++ // Mark scope with SehTryBegin
++ if (getLangOpts().EHAsynch)
++ EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
+ }
+ }
+ }
+@@ -720,7 +737,7 @@ llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
+ // If exceptions are disabled/ignored and SEH is not in use, then there is no
+ // invoke destination. SEH "works" even if exceptions are off. In practice,
+ // this means that C++ destructors and other EH cleanups don't run, which is
+- // consistent with MSVC's behavior.
++ // consistent with MSVC's behavior, except in the presence of -EHa
+ const LangOptions &LO = CGM.getLangOpts();
+ if (!LO.Exceptions || LO.IgnoreExceptions) {
+ if (!LO.Borland && !LO.MicrosoftExt)
+@@ -1610,7 +1627,23 @@ void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
+ JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
+
+ SEHTryEpilogueStack.push_back(&TryExit);
++
++ llvm::BasicBlock *TryBB = nullptr;
++ // IsEHa: emit an invoke to _seh_try_begin() runtime for -EHa
++ if (getLangOpts().EHAsynch) {
++ EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
++ if (SEHTryEpilogueStack.size() == 1) // outermost only
++ TryBB = Builder.GetInsertBlock();
++ }
++
+ EmitStmt(S.getTryBlock());
++
++ // Volatilize all blocks in Try, till current insert point
++ if (TryBB) {
++ llvm::SmallPtrSet<llvm::BasicBlock *, 10> Visited;
++ VolatilizeTryBlocks(TryBB, Visited);
++ }
++
+ SEHTryEpilogueStack.pop_back();
+
+ if (!TryExit.getBlock()->use_empty())
+@@ -1621,6 +1654,38 @@ void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
+ ExitSEHTryStmt(S);
+ }
+
++// Recursively walk through blocks in a _try
++// and make all memory instructions volatile
++void CodeGenFunction::VolatilizeTryBlocks(
++ llvm::BasicBlock *BB, llvm::SmallPtrSet<llvm::BasicBlock *, 10> &V) {
++ if (BB == SEHTryEpilogueStack.back()->getBlock() /* end of Try */ ||
++ !V.insert(BB).second /* already visited */ ||
++ !BB->getParent() /* not emitted */ || BB->empty())
++ return;
++
++ if (!BB->isEHPad()) {
++ for (llvm::BasicBlock::iterator J = BB->begin(), JE = BB->end(); J != JE;
++ ++J) {
++ if (isa<llvm::LoadInst>(J)) {
++ auto LI = cast<llvm::LoadInst>(J);
++ LI->setVolatile(true);
++ } else if (isa<llvm::StoreInst>(J)) {
++ auto SI = cast<llvm::StoreInst>(J);
++ SI->setVolatile(true);
++ } else if (isa<llvm::MemIntrinsic>(J)) {
++ auto *MCI = cast<llvm::MemIntrinsic>(J);
++ MCI->setVolatile(llvm::ConstantInt::get(Builder.getInt1Ty(), 1));
++ }
++ }
++ }
++ const llvm::Instruction *TI = BB->getTerminator();
++ if (TI) {
++ unsigned N = TI->getNumSuccessors();
++ for (unsigned I = 0; I < N; I++)
++ VolatilizeTryBlocks(TI->getSuccessor(I), V);
++ }
++}
++
+ namespace {
+ struct PerformSEHFinally final : EHScopeStack::Cleanup {
+ llvm::Function *OutlinedFinally;
+@@ -2101,6 +2166,12 @@ void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S) {
+ return;
+ }
+
++ // IsEHa: emit an invoke _seh_try_end() to mark end of FT flow
++ if (getLangOpts().EHAsynch && Builder.GetInsertBlock()) {
++ llvm::FunctionCallee SehTryEnd = getSehTryEndFn(CGM);
++ EmitRuntimeCallOrInvoke(SehTryEnd);
++ }
++
+ // Otherwise, we must have an __except block.
+ const SEHExceptStmt *Except = S.getExceptHandler();
+ assert(Except && "__try must have __finally xor __except");
+diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
+index 672909849bb..32dca08b8cf 100644
+--- a/clang/lib/CodeGen/CGStmt.cpp
++++ b/clang/lib/CodeGen/CGStmt.cpp
+@@ -606,6 +606,11 @@ void CodeGenFunction::LexicalScope::rescopeLabels() {
+
+ void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
+ EmitLabel(S.getDecl());
++
++ // IsEHa - emit eha.scope.begin if it's a side entry of a scope
++ if (getLangOpts().EHAsynch && S.isSideEntry())
++ EmitSehCppScopeBegin();
++
+ EmitStmt(S.getSubStmt());
+ }
+
+diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
+index d794f4f0fa8..1b5892c7459 100644
+--- a/clang/lib/CodeGen/CodeGenFunction.h
++++ b/clang/lib/CodeGen/CodeGenFunction.h
+@@ -2784,6 +2784,11 @@ public:
+ void EmitCXXTemporary(const CXXTemporary *Temporary, QualType TempType,
+ Address Ptr);
+
++ void EmitSehCppScopeBegin();
++ void EmitSehCppScopeEnd();
++ void EmitSehTryScopeBegin();
++ void EmitSehTryScopeEnd();
++
+ llvm::Value *EmitLifetimeStart(uint64_t Size, llvm::Value *Addr);
+ void EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr);
+
+@@ -3134,6 +3139,8 @@ public:
+ void EmitSEHLeaveStmt(const SEHLeaveStmt &S);
+ void EnterSEHTryStmt(const SEHTryStmt &S);
+ void ExitSEHTryStmt(const SEHTryStmt &S);
++ void VolatilizeTryBlocks(llvm::BasicBlock *BB,
++ llvm::SmallPtrSet<llvm::BasicBlock *, 10> &V);
+
+ void pushSEHCleanup(CleanupKind kind,
+ llvm::Function *FinallyFunc);
+diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
+index 4ae8ce7e5cc..5512c8fe88a 100644
+--- a/clang/lib/CodeGen/CodeGenModule.cpp
++++ b/clang/lib/CodeGen/CodeGenModule.cpp
+@@ -593,6 +593,9 @@ void CodeGenModule::Release() {
+ llvm::DenormalMode::IEEE);
+ }
+
++ if (LangOpts.EHAsynch)
++ getModule().addModuleFlag(llvm::Module::Warning, "eh-asynch", 1);
++
+ // Emit OpenCL specific module metadata: OpenCL/SPIR version.
+ if (LangOpts.OpenCL) {
+ EmitOpenCLMetadata();
+diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+index 45c6cb6b2e0..a080c93356a 100644
+--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
++++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+@@ -131,7 +131,12 @@ public:
+
+ /// MSVC needs an extra flag to indicate a catchall.
+ CatchTypeInfo getCatchAllTypeInfo() override {
+- return CatchTypeInfo{nullptr, 0x40};
++ // For -EHa catch(...) must handle HW exception
++ // Adjective = HT_IsStdDotDot (0x40), only catch C++ exceptions
++ if (getContext().getLangOpts().EHAsynch)
++ return CatchTypeInfo{nullptr, 0};
++ else
++ return CatchTypeInfo{nullptr, 0x40};
+ }
+
+ bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
+diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
+index af4bcf951e6..71112783ac0 100644
+--- a/clang/lib/Driver/ToolChains/Clang.cpp
++++ b/clang/lib/Driver/ToolChains/Clang.cpp
+@@ -415,6 +415,7 @@ static void addExceptionArgs(const ArgList &Args, types::ID InputType,
+ Args.ClaimAllArgs(options::OPT_fobjc_exceptions);
+ Args.ClaimAllArgs(options::OPT_fno_objc_exceptions);
+ Args.ClaimAllArgs(options::OPT_fcxx_exceptions);
++ Args.ClaimAllArgs(options::OPT_feh_asynch);
+ Args.ClaimAllArgs(options::OPT_fno_cxx_exceptions);
+ return;
+ }
+@@ -423,6 +424,13 @@ static void addExceptionArgs(const ArgList &Args, types::ID InputType,
+ bool EH = Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions,
+ false);
+
++ bool EHa =
++ Args.hasFlag(options::OPT_feh_asynch, options::OPT_fno_eh_asynch, false);
++ if (EHa) {
++ CmdArgs.push_back("-feh-asynch");
++ EH = true;
++ }
++
+ // Obj-C exceptions are enabled by default, regardless of -fexceptions. This
+ // is not necessarily sensible, but follows GCC.
+ if (types::isObjC(InputType) &&
+@@ -6581,7 +6589,10 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
+ if (types::isCXX(InputType))
+ CmdArgs.push_back("-fcxx-exceptions");
+ CmdArgs.push_back("-fexceptions");
++ if (EH.Asynch)
++ CmdArgs.push_back("-feh-asynch");
+ }
++
+ if (types::isCXX(InputType) && EH.Synch && EH.NoUnwindC)
+ CmdArgs.push_back("-fexternc-nounwind");
+
+diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
+index 73114c6d76c..b58af0b68e7 100644
+--- a/clang/lib/Frontend/CompilerInvocation.cpp
++++ b/clang/lib/Frontend/CompilerInvocation.cpp
+@@ -2819,6 +2819,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
+ Opts.IgnoreExceptions = Args.hasArg(OPT_fignore_exceptions);
+ Opts.ObjCExceptions = Args.hasArg(OPT_fobjc_exceptions);
+ Opts.CXXExceptions = Args.hasArg(OPT_fcxx_exceptions);
++ Opts.EHAsynch = Args.hasArg(OPT_feh_asynch);
+
+ // -ffixed-point
+ Opts.FixedPoint =
+diff --git a/clang/lib/Sema/JumpDiagnostics.cpp b/clang/lib/Sema/JumpDiagnostics.cpp
+index b34243edea3..cbc309a3d42 100644
+--- a/clang/lib/Sema/JumpDiagnostics.cpp
++++ b/clang/lib/Sema/JumpDiagnostics.cpp
+@@ -930,6 +930,9 @@ void JumpScopeChecker::CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
+ if (!ToScopesWarning.empty()) {
+ S.Diag(DiagLoc, JumpDiagWarning);
+ NoteJumpIntoScopes(ToScopesWarning);
++ assert(isa<LabelStmt>(To));
++ LabelStmt *Label = cast<LabelStmt>(To);
++ Label->setSideEntry();
+ }
+
+ // Handle errors.
+diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
+index 9b58b9dfb17..1738ccd94ee 100644
+--- a/llvm/docs/LangRef.rst
++++ b/llvm/docs/LangRef.rst
+@@ -11642,6 +11642,59 @@ The '``llvm.localescape``' intrinsic blocks inlining, as inlining changes where
+ the escaped allocas are allocated, which would break attempts to use
+ '``llvm.localrecover``'.
+
++'``llvm.seh.try.begin``' and '``llvm.seh.try.end``' Intrinsics
++^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
++
++Syntax:
++"""""""
++
++::
++
++ declare void @llvm.seh.try.begin()
++ declare void @llvm.seh.try.end()
++
++Overview:
++"""""""""
++
++The '``llvm.seh.try.begin``' and '``llvm.seh.try.end``' intrinsics mark
++the boundary of a _try region for Windows SEH Asynchrous Exception Handling.
++
++Semantics:
++""""""""""
++
++When a C-function is compiled with Windows SEH Asynchrous Exception option,
++-feh_asynch (aka MSVC -EHa), these two intrinsics are injected to mark _try
++boundary and to prevent from potential exceptions being moved across boundary.
++
++'``llvm.eha.scope.begin``' and '``llvm.eha.scope.end``' Intrinsics
++^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
++
++Syntax:
++"""""""
++
++::
++
++ declare void @llvm.eha.scope.begin()
++ declare void @llvm.eha.scope.end()
++
++Overview:
++"""""""""
++
++The '``llvm.eha.scope.begin``' and '``llvm.eha.scope.end``' intrinsics mark
++the boundary of a CPP object lifetime for Windows SEH Asynchrous Exception
++Handling (MSVC option -EHa).
++
++Semantics:
++""""""""""
++
++'``llvm.eha.scope.begin``' is added immediately after an object constructor is
++called, i.e., EHStack is not empty. So it will be an invoke, not a call.
++With that it's also guaranteed that an associated EH-cleanup-pad is
++created in IR regardless whether there exists a call in this object lifetime.
++'``llvm.eha.scope.end``' is added before the object destructor.
++These intrinsics make Block-level State computation possible in downstream
++LLVM code gen pass, even in the presence of ctor/dtor inlining.
++
+ .. _int_read_register:
+ .. _int_read_volatile_register:
+ .. _int_write_register:
+diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
+index 4918ea876df..7de760291d9 100644
+--- a/llvm/include/llvm/IR/Intrinsics.td
++++ b/llvm/include/llvm/IR/Intrinsics.td
+@@ -481,6 +481,16 @@ def int_eh_recoverfp : Intrinsic<[llvm_ptr_ty],
+ [llvm_ptr_ty, llvm_ptr_ty],
+ [IntrNoMem]>;
+
++// To mark the beginning/end of a try-scope for Windows SEH -EHa
++// calls/invokes to these intrinsics are placed to model control flows
++// caused by HW exceptions under option -EHa.
++// calls/invokes to these intrinsics will be discarded during a codegen pass
++// after EH tables are generated
++def int_seh_try_begin : Intrinsic<[], [], [IntrReadMem, IntrWriteMem, IntrWillReturn]>;
++def int_seh_try_end : Intrinsic<[], [], [IntrReadMem, IntrWriteMem, IntrWillReturn]>;
++def int_eha_scope_begin : Intrinsic<[], [], [IntrNoMem]>;
++def int_eha_scope_end : Intrinsic<[], [], [IntrNoMem]>;
++
+ // Note: we treat stacksave/stackrestore as writemem because we don't otherwise
+ // model their dependencies on allocas.
+ def int_stacksave : Intrinsic<[llvm_ptr_ty]>,
+diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+index d2930391f87..7e58de39962 100644
+--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
++++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+@@ -2801,6 +2801,10 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
+ llvm_unreachable("Cannot invoke this intrinsic");
+ case Intrinsic::donothing:
+ // Ignore invokes to @llvm.donothing: jump directly to the next BB.
++ case Intrinsic::seh_try_begin:
++ case Intrinsic::eha_scope_begin:
++ case Intrinsic::seh_try_end:
++ case Intrinsic::eha_scope_end:
+ break;
+ case Intrinsic::experimental_patchpoint_void:
+ case Intrinsic::experimental_patchpoint_i64:
+@@ -6635,6 +6639,10 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
+ lowerCallToExternalSymbol(I, FunctionName);
+ return;
+ case Intrinsic::donothing:
++ case Intrinsic::seh_try_begin:
++ case Intrinsic::eha_scope_begin:
++ case Intrinsic::seh_try_end:
++ case Intrinsic::eha_scope_end:
+ // ignore
+ return;
+ case Intrinsic::experimental_stackmap:
+diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
+index c518ae87ea9..87dd063ee2e 100644
+--- a/llvm/lib/IR/Verifier.cpp
++++ b/llvm/lib/IR/Verifier.cpp
+@@ -4269,6 +4269,10 @@ void Verifier::visitInstruction(Instruction &I) {
+ Assert(
+ !F->isIntrinsic() || isa<CallInst>(I) ||
+ F->getIntrinsicID() == Intrinsic::donothing ||
++ F->getIntrinsicID() == Intrinsic::seh_try_begin ||
++ F->getIntrinsicID() == Intrinsic::seh_try_end ||
++ F->getIntrinsicID() == Intrinsic::eha_scope_begin ||
++ F->getIntrinsicID() == Intrinsic::eha_scope_end ||
+ F->getIntrinsicID() == Intrinsic::coro_resume ||
+ F->getIntrinsicID() == Intrinsic::coro_destroy ||
+ F->getIntrinsicID() == Intrinsic::experimental_patchpoint_void ||