Add tests which ensure that the data produced by the preparser is really used.

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index 7d1f46ccb3ff83e03b1eddf5f768156dfa564f72..5ae7b527348e602047f8666e3d4482a2aff260bf 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -260,6 +260,86 @@ TEST(Preparsing) {
 }
 
 
+TEST(PreparseFunctionDataIsUsed) {
+  // This tests that we actually do use the function data generated by the
+  // preparser.
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope handles(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+  int marker;
+  CcTest::i_isolate()->stack_guard()->SetStackLimit(
+      reinterpret_cast<uintptr_t>(&marker) - 128 * 1024);
+
+  const char* good_source =
+      "function this_is_lazy() { var a; } function foo() { return 25; } foo();";
+
+  // Insert a syntax error inside the lazy function.
+  const char* bad_source =
+      "function this_is_lazy() { if (   } function foo() { return 25; } foo();";
+
+  v8::ScriptData* preparse = v8::ScriptData::PreCompile(v8_str(good_source));
+  CHECK(!preparse->HasError());
+
+  // Now compile the erroneous code with the good preparse data. If the preparse
+  // data is used, the lazy function is skipped and it should compile fine.
+  v8::ScriptCompiler::Source source(
+      v8_str(bad_source),
+      v8::ScriptCompiler::CachedData(
+          reinterpret_cast<const uint8_t*>(preparse->Data()),
+          preparse->Length()));
+  v8::Local<v8::Value> result =
+      v8::ScriptCompiler::Compile(CcTest::isolate(), source)->Run();
+  CHECK(result->IsInt32());
+  CHECK_EQ(25, result->Int32Value());
+  delete preparse;
+}
+
+
+TEST(PreparseSymbolDataIsUsed) {
+  // This tests that we actually do use the symbol data generated by the
+  // preparser.
+
+  // Only do one compilation pass in this test (otherwise we will parse the
+  // source code again without preparse data and it will fail).
+  i::FLAG_crankshaft = false;
+
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope handles(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+  int marker;
+  CcTest::i_isolate()->stack_guard()->SetStackLimit(
+      reinterpret_cast<uintptr_t>(&marker) - 128 * 1024);
+
+  // Note that the ( before function makes the

[rossberg, 2014/03/17 12:08:40]

Broken comment?

+  const char* good_source =
+      "(function weird() { var foo = 26; return foo; })()";
+
+  // Insert an undefined identifier. If the preparser data is used, the symbol
+  // stream is used instead, and this identifier resolves correctly to"foo".

[rossberg, 2014/03/17 12:08:40]

Nit: to"foo" -> to "foo"

Also, I personally wouldn't use the word "correctly" here. :)

+  const char* bad_source =
+      "(function weird() { var foo = 26; return wut; })()";
+
+  v8::ScriptData* preparse = v8::ScriptData::PreCompile(v8_str(good_source));
+  CHECK(!preparse->HasError());
+
+  // Now compile the erroneous code with the good preparse data. If the preparse
+  // data is used, we will see a second occurrence of "foo" instead of the
+  // unknown "wut".
+  v8::ScriptCompiler::Source source(
+      v8_str(bad_source),
+      v8::ScriptCompiler::CachedData(
+          reinterpret_cast<const uint8_t*>(preparse->Data()),
+          preparse->Length()));
+  v8::Local<v8::Value> result =
+      v8::ScriptCompiler::Compile(CcTest::isolate(), source)->Run();
+  CHECK(result->IsInt32());
+  CHECK_EQ(26, result->Int32Value());
+  delete preparse;
+}
+
+
 TEST(StandAlonePreParser) {
   v8::V8::Initialize();