[test] Improve some error messages and comments

Change-Id: I8ac9f04ce8410f8ca81b1436850cd96ce79a3b6d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3122161
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76535}

test/cctest/wasm/test-run-wasm-wrappers.cc

@@ -28,6 +28,7 @@ Handle<WasmInstanceObject> CompileModule(Zone* zone, Isolate* isolate,
   MaybeHandle<WasmInstanceObject> maybe_instance =
       CompileAndInstantiateForTesting(
           isolate, &thrower, ModuleWireBytes(buffer.begin(), buffer.end()));
+  CHECK_WITH_MSG(!thrower.error(), thrower.error_msg());
   return maybe_instance.ToHandleChecked();
 }
 

test/fuzzer/wasm-compile.cc

@@ -582,8 +582,11 @@ class WasmGenerator {
       if (call_direct) {
         builder_->EmitWithU32V(kExprReturnCall, func_index);
       } else {
+        // This will not trap because table[func_index] always contains function
+        // func_index.
         builder_->EmitI32Const(func_index);
         builder_->EmitWithU32V(kExprReturnCallIndirect, sig_index);
+        // TODO(11954): Use other table indices too.
         builder_->EmitByte(0);  // Table index.
       }
       return;
@@ -591,8 +594,11 @@ class WasmGenerator {
       if (call_direct) {
         builder_->EmitWithU32V(kExprCallFunction, func_index);
       } else {
+        // This will not trap because table[func_index] always contains function
+        // func_index.
         builder_->EmitI32Const(func_index);
         builder_->EmitWithU32V(kExprCallIndirect, sig_index);
+        // TODO(11954): Use other table indices too.
         builder_->EmitByte(0);  // Table index.
       }
     }
@@ -1730,7 +1736,7 @@ void WasmGenerator::GenerateOptRef(HeapType type, DataRange* data) {
     // default case.
     case HeapType::kAny: {
       // Weighed according to the types in the module.
-      // TODO(manoskouk): Generate i31ref.
+      // TODO(11954): Generate i31ref.
       uint32_t num_types = builder_->builder()->NumTypes();
       uint8_t random = data->get<uint8_t>() % (num_types + 2);
       if (random < num_structs_ + num_arrays_) {
@@ -1769,7 +1775,7 @@ void WasmGenerator::GenerateOptRef(HeapType type, DataRange* data) {
       // Else fall back to the default case outside the switch.
       break;
     }
-    // TODO(manoskouk): Add i31ref case.
+    // TODO(11954): Add i31ref case.
     default:
       break;
   }

test/fuzzer/wasm-fuzzer-common.cc

@@ -362,7 +362,7 @@ void GenerateTestCase(Isolate* isolate, ModuleWireBytes wire_bytes,
       ModuleOrigin::kWasmOrigin, isolate->counters(),
       isolate->metrics_recorder(), v8::metrics::Recorder::ContextId::Empty(),
       DecodingMethod::kSync, GetWasmEngine()->allocator());
-  CHECK(module_res.ok());
+  CHECK_WITH_MSG(module_res.ok(), module_res.error().message().c_str());
   WasmModule* module = module_res.value().get();
   CHECK_NOT_NULL(module);