Fix bug in the Wasm Exception error message memory handling

Author: Cellule

lib/Runtime/Library/WasmLibrary.cpp

@@ -13,7 +13,7 @@ namespace Js
 {
     const unsigned int WasmLibrary::experimentalVersion = Wasm::experimentalVersion;
 
-    char16* lastWasmExceptionMessage = nullptr;
+    char16* WasmLibrary::lastWasmExceptionMessage = nullptr;
 
     Var WasmLibrary::instantiateModule(RecyclableObject* function, CallInfo callInfo, ...)
     {
@@ -168,9 +168,11 @@ namespace Js
             }
 #endif
         }
-        catch (Wasm::WasmCompilationException ex)
+        catch (Wasm::WasmCompilationException& ex)
         {
-            Wasm::WasmCompilationException newEx(_u("function %s: %s"), body->GetDisplayName(), ex.GetErrorMessage());
+            char16* originalMessage = ex.ReleaseErrorMessage();
+            Wasm::WasmCompilationException newEx = Wasm::WasmCompilationException(_u("function %s: %s"), body->GetDisplayName(), originalMessage);
+            SysFreeString(originalMessage);
             if (propagateError)
             {
                 throw newEx;

lib/Runtime/Library/WasmLibrary.h

@@ -48,6 +48,7 @@ namespace Js
             Js::Var ffi,
             Js::Var* start = nullptr
         );
+        static char16* lastWasmExceptionMessage;
 #endif
     };
 }

lib/WasmReader/WasmByteCodeGenerator.cpp

@@ -1477,14 +1477,6 @@ WasmCompilationException::FormatError(const char16* _msg, va_list arglist)
     errorMsg = SysAllocString(buf);
 }
 
-WasmCompilationException::~WasmCompilationException()
-{
-    if (errorMsg)
-    {
-        SysFreeString(errorMsg);
-    }
-}
-
 WasmCompilationException::WasmCompilationException(const char16* _msg, ...)
 {
     va_list arglist;

lib/WasmReader/WasmByteCodeGenerator.h

@@ -45,20 +45,9 @@ namespace Wasm
         void FormatError(const char16* _msg, va_list arglist);
         char16* errorMsg;
     public:
-        ~WasmCompilationException();
         WasmCompilationException(const char16* _msg, ...);
         WasmCompilationException(const char16* _msg, va_list arglist);
 
-        void SetErrorMessage(char16* _errorMsg)
-        {
-            errorMsg = _errorMsg;
-        }
-
-        const char16* GetErrorMessage() const
-        {
-            return errorMsg;
-        }
-
         char16* ReleaseErrorMessage()
         {
             Assert(errorMsg);