[EH] Remove !rethrown check when destroying exception

src/lib/libemval.js

@@ -452,7 +452,6 @@ ${functionBody}
 #if !DISABLE_EXCEPTION_CATCHING
       var info = new ExceptionInfo(object.excPtr);
       info.set_caught(false);
-      info.set_rethrown(false);
       exceptionLast = object;
 #endif
       incrementUncaughtExceptionCount();

src/lib/libexceptions.js

@@ -54,15 +54,6 @@ var LibraryExceptions = {
       return {{{ makeGetValue('this.ptr', C_STRUCTS.__cxa_exception.caught, 'i8') }}} != 0;
     }
 
-    set_rethrown(rethrown) {
-      rethrown = rethrown ? 1 : 0;
-      {{{ makeSetValue('this.ptr', C_STRUCTS.__cxa_exception.rethrown, 'rethrown', 'i8') }}};
-    }
-
-    get_rethrown() {
-      return {{{ makeGetValue('this.ptr', C_STRUCTS.__cxa_exception.rethrown, 'i8') }}} != 0;
-    }
-
     // Initialize native structure fields. Should be called once after allocated.
     init(type, destructor) {
 #if EXCEPTION_DEBUG
@@ -116,9 +107,6 @@ var LibraryExceptions = {
     __Unwind_RaiseException(ptr);
   },
 
-  // This exception will be caught twice, but while begin_catch runs twice,
-  // we early-exit from end_catch when the exception has been rethrown, so
-  // pop that here from the caught exceptions.
   __cxa_rethrow__deps: ['$exceptionCaught', '$uncaughtExceptionCount',
 #if !DISABLE_EXCEPTION_CATCHING
     '$exceptionLast',
@@ -132,7 +120,6 @@ var LibraryExceptions = {
     }
     var info = exceptionCaught.at(-1);
     var ptr = info.excPtr;
-    info.set_rethrown(true);
     info.set_caught(false);
     uncaughtExceptionCount++;
 #if !DISABLE_EXCEPTION_CATCHING
@@ -156,7 +143,6 @@ var LibraryExceptions = {
       info.set_caught(true);
       uncaughtExceptionCount--;
     }
-    info.set_rethrown(false);
     exceptionCaught.push(info);
 #if EXCEPTION_DEBUG
     dbg('__cxa_begin_catch ' + [ptrToString(ptr), 'stack', exceptionCaught]);
@@ -227,7 +213,6 @@ var LibraryExceptions = {
     dbg('__cxa_rethrow_primary_exception: ' + ptrToString(ptr));
 #endif
     var info = new ExceptionInfo(ptr);
-    info.set_rethrown(true);
     info.set_caught(false);
     uncaughtExceptionCount++;
 #if !DISABLE_EXCEPTION_CATCHING

src/struct_info_cxx.json

@@ -6,7 +6,6 @@
               "exceptionDestructor",
               "exceptionType",
               "caught",
-              "rethrown",
               "adjustedPtr"
             ]
         }

src/struct_info_generated.json

@@ -927,8 +927,7 @@
             "adjustedPtr": 16,
             "caught": 12,
             "exceptionDestructor": 8,
-            "exceptionType": 4,
-            "rethrown": 13
+            "exceptionType": 4
         },
         "__wasi_fdstat_t": {
             "__size__": 24,

src/struct_info_generated_wasm64.json

@@ -927,8 +927,7 @@
             "adjustedPtr": 32,
             "caught": 24,
             "exceptionDestructor": 16,
-            "exceptionType": 8,
-            "rethrown": 25
+            "exceptionType": 8
         },
         "__wasi_fdstat_t": {
             "__size__": 24,

system/lib/libcxxabi/src/cxa_exception.h

@@ -27,7 +27,6 @@ struct _LIBCXXABI_HIDDEN __cxa_exception {
   // In wasm, destructors return 'this' as in ARM
   void* (*exceptionDestructor)(void *);
   uint8_t caught;
-  uint8_t rethrown;
   void *adjustedPtr;
   // Add padding to ensure that the size of __cxa_exception is a multiple of
   // the maximum useful alignment for the target machine.  This ensures that

system/lib/libcxxabi/src/cxa_exception_emscripten.cpp

@@ -4,10 +4,9 @@
 //  TODO(sbc): consider merging them
 //
 //  Notable changes:
- //   __cxa_allocate_exception doesn't add get_cxa_exception_offset
-//    __cxa_decrement_exception_refcount doesn't call the destructor if rethrown
-//  Both of these changes are mirrored from the historical JS implementation of
-//  these functions.
+//   __cxa_allocate_exception doesn't add get_cxa_exception_offset
+//  This change is mirrored from the historical JS implementation of
+//  this function.
 //
 //===----------------------------------------------------------------------===//
 
@@ -144,10 +143,9 @@ void __cxa_decrement_exception_refcount(void *thrown_object) throw() {
     if (thrown_object != NULL )
     {
         __cxa_exception* exception_header = cxa_exception_from_thrown_object(thrown_object);
-        DEBUG("DEC: %p refcnt=%zu rethrown=%d", thrown_object,
-              exception_header->referenceCount, exception_header->rethrown);
+        DEBUG("DEC: %p refcnt=%zu", thrown_object, exception_header->referenceCount);
         assert(exception_header->referenceCount > 0);
-        if (std::__libcpp_atomic_add(&exception_header->referenceCount, size_t(-1)) == 0 && !exception_header->rethrown)
+        if (std::__libcpp_atomic_add(&exception_header->referenceCount, size_t(-1)) == 0)
         {
             DEBUG("DEL: %p (dtor=%p)", thrown_object, exception_header->exceptionDestructor);
             if (NULL != exception_header->exceptionDestructor)

test/codesize/test_codesize_cxx_except.json

@@ -1,10 +1,10 @@
 {
-  "a.out.js": 22820,
-  "a.out.js.gz": 9041,
-  "a.out.nodebug.wasm": 176407,
-  "a.out.nodebug.wasm.gz": 58760,
-  "total": 199227,
-  "total_gz": 67801,
+  "a.out.js": 22796,
+  "a.out.js.gz": 9032,
+  "a.out.nodebug.wasm": 176397,
+  "a.out.nodebug.wasm.gz": 58755,
+  "total": 199193,
+  "total_gz": 67787,
   "sent": [
     "__cxa_begin_catch",
     "__cxa_end_catch",

test/codesize/test_codesize_cxx_mangle.json

@@ -1,10 +1,10 @@
 {
-  "a.out.js": 22870,
-  "a.out.js.gz": 9061,
-  "a.out.nodebug.wasm": 242680,
-  "a.out.nodebug.wasm.gz": 80978,
-  "total": 265550,
-  "total_gz": 90039,
+  "a.out.js": 22846,
+  "a.out.js.gz": 9052,
+  "a.out.nodebug.wasm": 242670,
+  "a.out.nodebug.wasm.gz": 80973,
+  "total": 265516,
+  "total_gz": 90025,
   "sent": [
     "__cxa_begin_catch",
     "__cxa_end_catch",

test/core/test_exceptions_refcount_2.cpp

@@ -0,0 +1,26 @@
+#include <cstdio>
+#include <emscripten.h>
+#include <exception>
+
+class MyException : public std::exception {
+public:
+  ~MyException() { puts("~MyException()"); }
+};
+
+EMSCRIPTEN_KEEPALIVE extern "C" void rethrow() {
+  try {
+    throw MyException();
+  } catch (...) {
+    throw;
+  }
+}
+
+int main() {
+  EM_ASM({
+    try {
+      _rethrow();
+    } catch (e) {
+      decrementExceptionRefcount(e);
+    }
+  });
+}

test/core/test_exceptions_refcount_2.out

@@ -0,0 +1 @@
+~MyException()

test/test_core.py

@@ -1478,6 +1478,11 @@ def test_exceptions_destroy_virtual(self):
   def test_exceptions_refcount(self):
     self.do_core_test('test_exceptions_refcount.cpp')
 
+  @with_all_eh_sjlj
+  def test_exceptions_refcount_2(self):
+    self.set_setting('ASSERTIONS')
+    self.do_core_test('test_exceptions_refcount_2.cpp')
+
   @with_all_eh_sjlj
   def test_exceptions_primary(self):
     self.do_core_test('test_exceptions_primary.cpp')