[Interpreter] Adds support for throw to bytecode graph builder.

test/cctest/compiler/test-run-bytecode-graph-builder.cc

Index: test/cctest/compiler/test-run-bytecode-graph-builder.cc
diff --git a/test/cctest/compiler/test-run-bytecode-graph-builder.cc b/test/cctest/compiler/test-run-bytecode-graph-builder.cc
index 248ff4b7ea19b4b78044af45b3e51d05f270aa33..9a91305b3b9475f074b643b1c8afbc48bdcd2ab9 100644
--- a/test/cctest/compiler/test-run-bytecode-graph-builder.cc
+++ b/test/cctest/compiler/test-run-bytecode-graph-builder.cc
@@ -88,6 +88,18 @@ class BytecodeGraphTester {
     return BytecodeGraphCallable<A...>(isolate_, GetFunction());
   }
 
+  Local<Message> CheckThrowsReturnMessage() {
+    TryCatch try_catch(reinterpret_cast<v8::Isolate*>(isolate_));
+    auto callable = GetCallable<>();
+    MaybeHandle<Object> no_result = callable();
+    CHECK(isolate_->has_pending_exception());
+    CHECK(try_catch.HasCaught());
+    CHECK(no_result.is_null());
+    isolate_->OptionalRescheduleException(true);
+    CHECK(!try_catch.Message().IsEmpty());
+    return try_catch.Message();
+  }
+
   static Handle<Object> NewObject(const char* script) {
     return v8::Utils::OpenHandle(*CompileRun(script));
   }
@@ -154,16 +166,14 @@ class BytecodeGraphTester {
   REPEAT_4(SEP, __VA_ARGS__) SEP() REPEAT_2(SEP, __VA_ARGS__) SEP() __VA_ARGS__
 
 
-template <int N>
+template <int N, typename T = Handle<Object>>
 struct ExpectedSnippet {
   const char* code_snippet;
-  Handle<Object> return_value_and_parameters[N + 1];
+  T return_value_and_parameters[N + 1];
 
-  inline Handle<Object> return_value() const {
-    return return_value_and_parameters[0];
-  }
+  inline T return_value() const { return return_value_and_parameters[0]; }
 
-  inline Handle<Object> parameter(int i) const {
+  inline T parameter(int i) const {
     DCHECK_GE(i, 0);
     DCHECK_LT(i, N);
     return return_value_and_parameters[1 + i];
@@ -951,6 +961,39 @@ TEST(BytecodeGraphBuilderTestInstanceOf) {
   // TODO(mythria): Add tests when CreateLiterals/CreateClousre are supported.
 }
 
+
+TEST(BytecodeGraphBuilderThrow) {
+  HandleAndZoneScope scope;
+  Isolate* isolate = scope.main_isolate();
+  Zone* zone = scope.main_zone();
+
+  // TODO(mythria): Add more tests when real try-catch and deoptimization
+  // information are supported.
+  ExpectedSnippet<0, const char*> snippets[] = {
+      {"throw undefined;", {"undefined"}},

[mythria, 2015/11/27 14:54:47]

I tried to add tests that throw an Error object. i.e. throw new Error('Error');
Theses tests crash in OptimizeFrame::Summarize. I thought it is related to the
unavailability of deopt information. Please correct me if I am wrong. I will try
to investigate why they failed. 

[Michael Starzinger, 2015/11/27 15:09:19]

Acknowledged. Yes, sounds about right. The constructor of an "Error" object will
try to collect a stack trace (i.e. see "function DefineError" in messages.js
file) and eventually lands in Runtime_CollectStackTrace and
OptimizeFrame::Summarize, causing the crash. Throwing any other object (e.g.
"throw new Object()") should work though, because only the "Error" constructors
capture stack traces. With the TODO you added above, the tests look good to me.

+      {"throw 1;", {"1"}},
+      {"throw 'Error';", {"Error"}},
+      {"throw 'Error1'; throw 'Error2'", {"Error1"}},
+      // TODO(mythria): Enable these tests when JumpIfTrue is supported.
+      // {"var a = true; if (a) { throw 'Error'; }", {"Error"}},
+  };
+
+  size_t num_snippets = sizeof(snippets) / sizeof(snippets[0]);
+  for (size_t i = 0; i < num_snippets; i++) {
+    ScopedVector<char> script(1024);
+    SNPrintF(script, "function %s() { %s }\n%s();", kFunctionName,
+             snippets[i].code_snippet, kFunctionName);
+    BytecodeGraphTester tester(isolate, zone, script.start());
+    v8::Local<v8::String> message = tester.CheckThrowsReturnMessage()->Get();
+    std::string str("Uncaught ");

[Michael Starzinger, 2015/11/27 15:09:19]

nit: I would just make the "Uncaught " prefix part of the ExpectedSnippet return
value above, makes it easier to read and I think the duplication is OK.

[mythria, 2015/11/27 15:40:44]

Done.

+    str += snippets[i].return_value();
+    v8::Local<v8::String> expected_string = v8_str(str.c_str());
+    CHECK(
+        message->Equals(CcTest::isolate()->GetCurrentContext(), expected_string)
+            .FromJust());
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8