feat: exception handling rework: unwind argument as integer.

Instead of using void* to represent the unwind argument, switch to using
an int. The argument was really just an int all along ,and we were
pretending it was a pointer to conform to the ABI.
Future changes related to Address Spaces will require changes to the ABI
anyway (the pointer would need an address space, probably multiple), so the
least painful option is to just use int.

clang/lib/CodeGen/CGException.cpp

@@ -62,8 +62,12 @@ static llvm::FunctionCallee getSehTryEndFn(CodeGenModule &CGM) {
 static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM) {
   // void __cxa_call_unexpected(void *thrown_exception);
 
+  llvm::Type* ArgTy = CGM.Int8PtrTy;
+  if (CGM.getLangOpts().Cheerp) {
+    ArgTy = CGM.Int32Ty;
+  }
   llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
+    llvm::FunctionType::get(CGM.VoidTy, ArgTy, /*isVarArg=*/false);
 
   return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
 }
@@ -96,8 +100,12 @@ llvm::FunctionCallee CodeGenModule::getTerminateFn() {
 
 static llvm::FunctionCallee getCatchallRethrowFn(CodeGenModule &CGM,
                                                  StringRef Name) {
+  llvm::Type* ArgTy = CGM.Int8PtrTy;
+  if (CGM.getLangOpts().Cheerp) {
+    ArgTy = CGM.Int32Ty;
+  }
   llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
+    llvm::FunctionType::get(CGM.VoidTy, ArgTy, /*isVarArg=*/false);
 
   return CGM.CreateRuntimeFunction(FTy, Name);
 }
@@ -460,9 +468,13 @@ void CodeGenFunction::EmitTypedPtrExprToExn(const Expr *e, Address addr) {
 
 
 Address CodeGenFunction::getExceptionSlot() {
+  llvm::Type* Ty = Int8PtrTy;
+  if(CGM.getLangOpts().Cheerp) {
+    Ty = Int32Ty;
+  }
   if (!ExceptionSlot)
-    ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
-  return Address(ExceptionSlot, Int8PtrTy, getPointerAlign());
+    ExceptionSlot = CreateTempAlloca(Ty, "exn.slot");
+  return Address(ExceptionSlot, Ty, getPointerAlign());
 }
 
 Address CodeGenFunction::getEHSelectorSlot() {
@@ -878,14 +890,6 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
   LPadInst = Builder.CreateLandingPad(LPadTy, 0);
 
   llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
-  if(!CGM.getTarget().isByteAddressable()) {
-    if (CGM.getTarget().getTriple().isCheerpWasm()) {
-      LPadExn = Builder.CreateIntToPtr(LPadExn, Int8PtrTy);
-    } else {
-      llvm::Function *MakeReg = CGM.getIntrinsic(llvm::Intrinsic::cheerp_make_regular, {Int8PtrTy, Int8PtrTy});
-      LPadExn = Builder.CreateCall(MakeReg, {llvm::ConstantPointerNull::get(Int8PtrTy), LPadExn});
-    }
-  }
   Builder.CreateStore(LPadExn, getExceptionSlot());
   llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
   Builder.CreateStore(LPadSel, getEHSelectorSlot());
@@ -1538,6 +1542,11 @@ void CodeGenFunction::FinallyInfo::exit(CodeGenFunction &CGF) {
     // If there's a begin-catch function, call it.
     if (BeginCatchFn) {
       exn = CGF.getExceptionFromSlot();
+      // In Cheerp Exn has type int, but the ObjC runtime expects void*.
+      // Just add an inttoptr here, we are doing it just to pass tests
+      if (CGF.getLangOpts().Cheerp && CGF.getLangOpts().ObjC) {
+        exn = CGF.Builder.CreateIntToPtr(exn, CGF.VoidPtrTy);
+      }
       CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
     }
 
@@ -1584,14 +1593,6 @@ llvm::BasicBlock *CodeGenFunction::getTerminateLandingPad() {
   llvm::Value *Exn = nullptr;
   if (getLangOpts().CPlusPlus) {
     Exn = Builder.CreateExtractValue(LPadInst, 0);
-    if(!CGM.getTarget().isByteAddressable()) {
-      if (CGM.getTarget().getTriple().isCheerpWasm()) {
-        Exn = Builder.CreateIntToPtr(Exn, Int8PtrTy);
-      } else {
-        llvm::Function *MakeReg = CGM.getIntrinsic(llvm::Intrinsic::cheerp_make_regular, {Int8PtrTy, Int8PtrTy});
-        Exn = Builder.CreateCall(MakeReg, {llvm::ConstantPointerNull::get(Int8PtrTy), Exn});
-      }
-    }
   }
   llvm::CallInst *terminateCall =
       CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
@@ -1692,14 +1693,6 @@ llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
 
   llvm::Type *LPadType = GetLandingPadTy();
   llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
-  if (!CGM.getTarget().isByteAddressable()) {
-    if (CGM.getTarget().getTriple().isCheerpWasm()) {
-      Exn = Builder.CreatePtrToInt(Exn, Int32Ty);
-    } else {
-      llvm::Function *PtrOffset = CGM.getIntrinsic(llvm::Intrinsic::cheerp_pointer_offset, {Int8PtrTy});
-      Exn = Builder.CreateCall(PtrOffset, Exn);
-    }
-  }
   LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
   LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
   Builder.CreateResume(LPadVal);

clang/lib/CodeGen/CGObjCRuntime.cpp

@@ -241,6 +241,11 @@ void CGObjCRuntime::EmitTryCatchStmt(CodeGenFunction &CGF,
     }
 
     llvm::Value *RawExn = CGF.getExceptionFromSlot();
+    // In Cheerp Exn has type int, but the ObjC runtime expects void*.
+    // Just add an inttoptr here, we are doing it just to pass tests
+    if (CGM.getLangOpts().Cheerp) {
+      RawExn = CGF.Builder.CreateIntToPtr(RawExn, CGM.VoidPtrTy);
+    }
 
     // Enter the catch.
     llvm::Value *Exn = RawExn;

clang/lib/CodeGen/CodeGenFunction.h

@@ -2010,7 +2010,7 @@ class CodeGenFunction : public CodeGenTypeCache {
 
   /// Get the named landingpad/resume type (Cheerp)
   llvm::StructType* GetLandingPadTy() {
-    if (getTarget().isByteAddressable()) {
+    if(!getLangOpts().Cheerp) {
       return llvm::StructType::get(Int8PtrTy, Int32Ty);
     }
     auto* Ret = llvm::StructType::getTypeByName(CGM.getLLVMContext(), "struct._ZN10__cxxabiv119__cheerp_landingpadE");

clang/lib/CodeGen/ItaniumCXXABI.cpp

@@ -4823,12 +4823,20 @@ void ItaniumCXXABI::emitCXXStructor(GlobalDecl GD) {
   }
 }
 
-static llvm::FunctionCallee getBeginCatchFn(CodeGenModule &CGM) {
+static llvm::FunctionCallee getBeginCatchFn(CodeGenModule &CGM, bool asmjs) {
+  llvm::Type* RetTy = CGM.Int8PtrTy;
+  llvm::Type* ArgTy = CGM.Int8PtrTy;
+  const char* name = "__cxa_begin_catch";
+  if (CGM.getLangOpts().Cheerp) {
+    ArgTy = CGM.Int32Ty;
+    if (asmjs)
+      name = "__cxa_begin_catch_wasm";
+  }
   // void *__cxa_begin_catch(void*);
   llvm::FunctionType *FTy = llvm::FunctionType::get(
-      CGM.Int8PtrTy, CGM.Int8PtrTy, /*isVarArg=*/false);
+      RetTy, ArgTy, /*isVarArg=*/false);
 
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_begin_catch");
+  return CGM.CreateRuntimeFunction(FTy, name);
 }
 
 static llvm::FunctionCallee getEndCatchFn(CodeGenModule &CGM) {
@@ -4839,12 +4847,20 @@ static llvm::FunctionCallee getEndCatchFn(CodeGenModule &CGM) {
   return CGM.CreateRuntimeFunction(FTy, "__cxa_end_catch");
 }
 
-static llvm::FunctionCallee getGetExceptionPtrFn(CodeGenModule &CGM) {
+static llvm::FunctionCallee getGetExceptionPtrFn(CodeGenModule &CGM, bool asmjs) {
+  llvm::Type* RetTy = CGM.Int8PtrTy;
+  llvm::Type* ArgTy = CGM.Int8PtrTy;
+  const char* name = "__cxa_get_exception_ptr";
+  if (CGM.getLangOpts().Cheerp) {
+    ArgTy = CGM.Int32Ty;
+    if (asmjs)
+      name = "__cxa_get_exception_ptr_wasm";
+  }
   // void *__cxa_get_exception_ptr(void*);
   llvm::FunctionType *FTy = llvm::FunctionType::get(
-      CGM.Int8PtrTy, CGM.Int8PtrTy, /*isVarArg=*/false);
+      RetTy, ArgTy, /*isVarArg=*/false);
 
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_get_exception_ptr");
+  return CGM.CreateRuntimeFunction(FTy, name);
 }
 
 namespace {
@@ -4882,8 +4898,9 @@ namespace {
 static llvm::Value *CallBeginCatch(CodeGenFunction &CGF,
                                    llvm::Value *Exn,
                                    bool EndMightThrow) {
+  bool asmjs = CGF.CurFn->getSection() == "asmjs";
   llvm::CallInst *call =
-    CGF.EmitNounwindRuntimeCall(getBeginCatchFn(CGF.CGM), Exn);
+    CGF.EmitNounwindRuntimeCall(getBeginCatchFn(CGF.CGM, asmjs), Exn);
 
   CGF.EHStack.pushCleanup<CallEndCatch>(NormalAndEHCleanup, EndMightThrow);
 
@@ -5035,10 +5052,11 @@ static void InitCatchParam(CodeGenFunction &CGF,
     return;
   }
 
+  bool asmjs = CGF.CurFn->getSection() == "asmjs";
   // We have to call __cxa_get_exception_ptr to get the adjusted
   // pointer before copying.
   llvm::CallInst *rawAdjustedExn =
-    CGF.EmitNounwindRuntimeCall(getGetExceptionPtrFn(CGF.CGM), Exn);
+    CGF.EmitNounwindRuntimeCall(getGetExceptionPtrFn(CGF.CGM, asmjs), Exn);
 
   // Cast that to the appropriate type.
   Address adjustedExn(CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy),
@@ -5116,8 +5134,13 @@ void ItaniumCXXABI::emitBeginCatch(CodeGenFunction &CGF,
 /// This code is used only in C++.
 static llvm::FunctionCallee getClangCallTerminateFn(CodeGenModule &CGM) {
   ASTContext &C = CGM.getContext();
+  bool asmjs = CGM.getTriple().isCheerpWasm();
+  CanQualType ArgTy = C.getPointerType(C.CharTy);
+  if (CGM.getLangOpts().Cheerp) {
+    ArgTy = C.IntTy;
+  }
   const CGFunctionInfo &FI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(
-      C.VoidTy, {C.getPointerType(C.CharTy)});
+      C.VoidTy, {ArgTy});
   llvm::FunctionType *fnTy = CGM.getTypes().GetFunctionType(FI);
   llvm::FunctionCallee fnRef = CGM.CreateRuntimeFunction(
       fnTy, "__clang_call_terminate", llvm::AttributeList(), /*Local=*/true);
@@ -5149,7 +5172,7 @@ static llvm::FunctionCallee getClangCallTerminateFn(CodeGenModule &CGM) {
     llvm::Value *exn = &*fn->arg_begin();
 
     // Call __cxa_begin_catch(exn).
-    llvm::CallInst *catchCall = builder.CreateCall(getBeginCatchFn(CGM), exn);
+    llvm::CallInst *catchCall = builder.CreateCall(getBeginCatchFn(CGM, asmjs), exn);
     catchCall->setDoesNotThrow();
     catchCall->setCallingConv(CGM.getRuntimeCC());
 

compiler-rt/lib/asan/asan_interceptors.cpp

@@ -349,8 +349,13 @@ extern "C" void __cxa_throw_wasm(void *a, void *b, void *c) {
 #endif
 
 
+#ifdef __CHEERP__
+#define UNWIND_ARG_TYPE int
+#else
+#define UNWIND_ARG_TYPE void*
+#endif
 #if ASAN_INTERCEPT___CXA_RETHROW_PRIMARY_EXCEPTION
-INTERCEPTOR(void, __cxa_rethrow_primary_exception, void *a) {
+INTERCEPTOR(void, __cxa_rethrow_primary_exception, UNWIND_ARG_TYPE a) {
   __asan_handle_no_return();
   REAL(__cxa_rethrow_primary_exception)(a);
 }

compiler-rt/lib/asan/asan_interceptors.h

@@ -172,7 +172,7 @@ DECLARE_REAL(size_t, mbstowcs, wchar_t *dest, const char *src, size_t len);
 DECLARE_REAL(size_t, mbsrtowcs, wchar_t *dest, const char **src, size_t len, void *ps);
 
 extern "C" void __cheerp___cxa_throw(void *, void *, void *);
-extern "C" void __cheerp___cxa_rethrow_primary_exception(void*);
+extern "C" void __cheerp___cxa_rethrow_primary_exception(int);
 #endif // SANITIZER_CHEERPWASM
 
 #  if !SANITIZER_APPLE

libcxx/include/exception

@@ -187,7 +187,12 @@ _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
 
 class _LIBCPP_TYPE_VIS exception_ptr
 {
-    void* __ptr_;
+#ifdef __CHEERP__
+    unsigned
+#else
+    void*
+#endif
+    __ptr_;
 public:
     _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
     _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
@@ -197,7 +202,7 @@ public:
     ~exception_ptr() _NOEXCEPT;
 
     _LIBCPP_INLINE_VISIBILITY explicit operator bool() const _NOEXCEPT
-    {return __ptr_ != nullptr;}
+    {return __ptr_ != 0;}
 
     friend _LIBCPP_INLINE_VISIBILITY
     bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT

libcxx/src/support/runtime/exception_pointer_cxxabi.ipp

@@ -47,7 +47,7 @@ _LIBCPP_NORETURN
 void
 nested_exception::rethrow_nested() const
 {
-    if (__ptr_ == nullptr)
+    if (__ptr_ == 0)
         terminate();
     rethrow_exception(__ptr_);
 }

libcxxabi/include/cxxabi.h

@@ -146,15 +146,21 @@ extern _LIBCXXABI_FUNC_VIS char *__cxa_demangle(const char *mangled_name,
                                                 char *output_buffer,
                                                 size_t *length, int *status);
 
+#ifdef __CHEERP__
+#define UNWIND_TY int
+#else
+#define UNWIND_TY void*
+#endif
+
 // Apple additions to support C++ 0x exception_ptr class
 // These are primitives to wrap a smart pointer around an exception object
-extern _LIBCXXABI_FUNC_VIS void *__cxa_current_primary_exception() throw();
+extern _LIBCXXABI_FUNC_VIS UNWIND_TY __cxa_current_primary_exception() throw();
 extern _LIBCXXABI_FUNC_VIS void
-__cxa_rethrow_primary_exception(void *primary_exception);
+__cxa_rethrow_primary_exception(UNWIND_TY primary_exception);
 extern _LIBCXXABI_FUNC_VIS void
-__cxa_increment_exception_refcount(void *primary_exception) throw();
+__cxa_increment_exception_refcount(UNWIND_TY primary_exception) throw();
 extern _LIBCXXABI_FUNC_VIS void
-__cxa_decrement_exception_refcount(void *primary_exception) throw();
+__cxa_decrement_exception_refcount(UNWIND_TY primary_exception) throw();
 
 // Apple extension to support std::uncaught_exception()
 extern _LIBCXXABI_FUNC_VIS bool __cxa_uncaught_exception() throw();