[wasm][fuzzer] Fix exception detection

Exceptions were detected by checking for a pending exception on the
isolate, but {CallWasmFunctionForTesting} was clearing any pending
exception before returning.
This CL fixes that by explicitly passing back a boolean which is set if
an exception occurred during execution.

R=ahaas@chromium.org

Bug: chromium:1115280
Change-Id: Ife71ceef0751d18e0870335b9520c2bf77e351cc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2352787Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69404}

test/common/wasm/wasm-module-runner.cc

@@ -172,7 +172,8 @@ MaybeHandle<WasmExportedFunction> GetExportedFunction(
 int32_t CallWasmFunctionForTesting(Isolate* isolate,
                                    Handle<WasmInstanceObject> instance,
                                    const char* name, int argc,
-                                   Handle<Object> argv[]) {
+                                   Handle<Object> argv[], bool* exception) {
+  if (exception) *exception = false;
   MaybeHandle<WasmExportedFunction> maybe_export =
       GetExportedFunction(isolate, instance, name);
   Handle<WasmExportedFunction> main_export;
@@ -189,6 +190,7 @@ int32_t CallWasmFunctionForTesting(Isolate* isolate,
   if (retval.is_null()) {
     DCHECK(isolate->has_pending_exception());
     isolate->clear_pending_exception();
+    if (exception) *exception = true;
     return -1;
   }
   Handle<Object> result = retval.ToHandleChecked();

test/common/wasm/wasm-module-runner.h

@@ -31,11 +31,13 @@ MaybeHandle<WasmExportedFunction> GetExportedFunction(
 
 // Call an exported wasm function by name. Returns -1 if the export does not
 // exist or throws an error. Errors are cleared from the isolate before
-// returning.
+// returning. {exception} is set to to true if an exception happened during
+// execution of the wasm function.
 int32_t CallWasmFunctionForTesting(Isolate* isolate,
                                    Handle<WasmInstanceObject> instance,
                                    const char* name, int argc,
-                                   Handle<Object> argv[]);
+                                   Handle<Object> argv[],
+                                   bool* exception = nullptr);
 
 // Decode, verify, and run the function labeled "main" in the
 // given encoded module. The module should have no imports.

test/fuzzer/wasm-fuzzer-common.cc

@@ -82,21 +82,19 @@ void InterpretAndExecuteModule(i::Isolate* isolate,
               .ToHandle(&instance));
   }
 
+  bool exception = false;
   int32_t result_compiled = testing::CallWasmFunctionForTesting(
-      isolate, instance, "main", 0, nullptr);
-  if (interpreter_result.trapped() != isolate->has_pending_exception()) {
+      isolate, instance, "main", 0, nullptr, &exception);
+  if (interpreter_result.trapped() != exception) {
     const char* exception_text[] = {"no exception", "exception"};
     FATAL("interpreter: %s; compiled: %s",
           exception_text[interpreter_result.trapped()],
-          exception_text[isolate->has_pending_exception()]);
+          exception_text[exception]);
   }
 
   if (interpreter_result.finished()) {
     CHECK_EQ(interpreter_result.result(), result_compiled);
   }
-
-  // Cleanup any pending exception.
-  isolate->clear_pending_exception();
 }
 
 namespace {