[Emscripten EH] Fix EXCEPTION_STACK_TRACES for resumeException case (#19099)

Author: ravisumit33

src/library_exceptions.js

@@ -188,9 +188,9 @@ var LibraryExceptions = {
     var info = new ExceptionInfo(ptr);
     // Initialize ExceptionInfo content after it was allocated in __cxa_allocate_exception.
     info.init(type, destructor);
-    exceptionLast = ptr;
+    {{{ storeException('exceptionLast', 'ptr') }}}
     uncaughtExceptionCount++;
-    {{{ makeThrow('ptr') }}}
+    {{{ makeThrow('exceptionLast') }}}
   },
 
   // This exception will be caught twice, but while begin_catch runs twice,
@@ -215,8 +215,8 @@ var LibraryExceptions = {
     dbg('__cxa_rethrow, popped ' +
       [ptrToString(ptr), exceptionLast, 'stack', exceptionCaught]);
 #endif
-    exceptionLast = ptr;
-    {{{ makeThrow('ptr') }}}
+    {{{ storeException('exceptionLast', 'ptr') }}}
+    {{{ makeThrow('exceptionLast') }}}
   },
 
   llvm_eh_typeid_for__sig: 'ip',
@@ -316,7 +316,12 @@ var LibraryExceptions = {
   __cxa_find_matching_catch__deps: ['$exceptionLast', '$ExceptionInfo', '__resumeException', '__cxa_can_catch', 'setTempRet0'],
   //__cxa_find_matching_catch__sig: 'p',
   __cxa_find_matching_catch: function() {
-    var thrown = exceptionLast;
+    var thrown = 
+#if EXCEPTION_STACK_TRACES
+      exceptionLast && exceptionLast.excPtr;
+#else
+      exceptionLast;
+#endif
     if (!thrown) {
       // just pass through the null ptr
       setTempRet0(0);
@@ -364,8 +369,10 @@ var LibraryExceptions = {
 #if EXCEPTION_DEBUG
     dbg("__resumeException " + [ptrToString(ptr), exceptionLast]);
 #endif
-    if (!exceptionLast) { exceptionLast = ptr; }
-    {{{ makeThrow('ptr') }}}
+    if (!exceptionLast) { 
+      {{{ storeException('exceptionLast', 'ptr') }}}
+    }
+    {{{ makeThrow('exceptionLast') }}}
   },
 
 #endif

src/parseTools.js

@@ -495,12 +495,14 @@ function makeThrow(excPtr) {
     }
     return `assert(false, '${assertInfo}');`;
   }
-  if (EXCEPTION_STACK_TRACES) {
-    return `throw new CppException(${excPtr});`;
-  }
   return `throw ${excPtr};`;
 }
 
+function storeException(varName, excPtr) {
+  var exceptionToStore = EXCEPTION_STACK_TRACES ? `new CppException(${excPtr})` : `${excPtr}`;
+  return `${varName} = ${exceptionToStore};`;
+}
+
 function charCode(char) {
   return char.charCodeAt(0);
 }

src/runtime_exceptions.js

@@ -15,6 +15,7 @@ class EmscriptenSjLj extends EmscriptenEH {}
 class CppException extends EmscriptenEH {
   constructor(excPtr) {
     super(excPtr);
+    this.excPtr = excPtr;
 #if !DISABLE_EXCEPTION_CATCHING
     const excInfo = getExceptionMessage(excPtr);
     this.name = excInfo[0];

test/test_other.py

@@ -8296,7 +8296,9 @@ def test_exceptions_stack_trace_and_message(self, wasm_eh):
         throw std::runtime_error("my message");
       }
       void foo() {
-        bar();
+        try {
+          bar();
+        } catch (const std::invalid_argument &err) {}
       }
       int main() {
         foo();