From 5d67eeca1a9f9c033b55f49c115e77b693ca4c07 Mon Sep 17 00:00:00 2001
From: Gus Caplan <me@gus.host>
Date: Wed, 14 Nov 2018 09:06:18 -0600
Subject: [PATCH] src: emit warnings from V8

PR-URL: https://github.com/nodejs/node/pull/24365
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 src/node.cc                 | 37 ++++++++++++++++++++++++++++++-------
 test/message/v8_warning.js  | 19 +++++++++++++++++++
 test/message/v8_warning.out |  1 +
 3 files changed, 50 insertions(+), 7 deletions(-)
 create mode 100644 test/message/v8_warning.js
 create mode 100644 test/message/v8_warning.out

diff --git a/src/node.cc b/src/node.cc
index 4c84f781707b01..153399f1b61777 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -1074,12 +1074,6 @@ static void DLOpen(const FunctionCallbackInfo<Value>& args) {
   // coverity[leaked_storage]
 }
 
-static void OnMessage(Local<Message> message, Local<Value> error) {
-  // The current version of V8 sends messages for errors only
-  // (thus `error` is always set).
-  FatalException(Isolate::GetCurrent(), error, message);
-}
-
 static Maybe<bool> ProcessEmitWarningGeneric(Environment* env,
                                              const char* warning,
                                              const char* type = nullptr,
@@ -1156,6 +1150,33 @@ Maybe<bool> ProcessEmitDeprecationWarning(Environment* env,
                                    deprecation_code);
 }
 
+static void OnMessage(Local<Message> message, Local<Value> error) {
+  Isolate* isolate = message->GetIsolate();
+  switch (message->ErrorLevel()) {
+    case Isolate::MessageErrorLevel::kMessageWarning: {
+      Environment* env = Environment::GetCurrent(isolate);
+      if (!env) {
+        break;
+      }
+      Utf8Value filename(isolate,
+          message->GetScriptOrigin().ResourceName());
+      // (filename):(line) (message)
+      std::stringstream warning;
+      warning << *filename;
+      warning << ":";
+      warning << message->GetLineNumber(env->context()).FromMaybe(-1);
+      warning << " ";
+      v8::String::Utf8Value msg(isolate, message->Get());
+      warning << *msg;
+      USE(ProcessEmitWarningGeneric(env, warning.str().c_str(), "V8"));
+      break;
+    }
+    case Isolate::MessageErrorLevel::kMessageError:
+      FatalException(isolate, error, message);
+      break;
+  }
+}
+
 
 static Local<Object> InitModule(Environment* env,
                                  node_module* mod,
@@ -2580,7 +2601,9 @@ Isolate* NewIsolate(ArrayBufferAllocator* allocator, uv_loop_t* event_loop) {
   v8_platform.Platform()->RegisterIsolate(isolate, event_loop);
   Isolate::Initialize(isolate, params);
 
-  isolate->AddMessageListener(OnMessage);
+  isolate->AddMessageListenerWithErrorLevel(OnMessage,
+      Isolate::MessageErrorLevel::kMessageError |
+      Isolate::MessageErrorLevel::kMessageWarning);
   isolate->SetAbortOnUncaughtExceptionCallback(ShouldAbortOnUncaughtException);
   isolate->SetMicrotasksPolicy(MicrotasksPolicy::kExplicit);
   isolate->SetFatalErrorHandler(OnFatalError);
diff --git a/test/message/v8_warning.js b/test/message/v8_warning.js
new file mode 100644
index 00000000000000..e3394cdd7094e8
--- /dev/null
+++ b/test/message/v8_warning.js
@@ -0,0 +1,19 @@
+'use strict';
+
+require('../common');
+
+function AsmModule() {
+  'use asm';
+
+  function add(a, b) {
+    a = a | 0;
+    b = b | 0;
+
+    // should be `return (a + b) | 0;`
+    return a + b;
+  }
+
+  return { add: add };
+}
+
+AsmModule();
diff --git a/test/message/v8_warning.out b/test/message/v8_warning.out
new file mode 100644
index 00000000000000..7943d0e9d64dfe
--- /dev/null
+++ b/test/message/v8_warning.out
@@ -0,0 +1 @@
+(node:*) V8: *v8_warning.js:* Invalid asm.js: Invalid return type