Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 9e8b06c6fc467e8ca7668d039df96b29a9f9c4eb..702b2650524fc4e88d25837011d2e4ec274ca1f3 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -13258,6 +13258,10 @@ Handle<String> JSFunction::ToString(Handle<JSFunction> function) {
     return NativeCodeFunctionSourceString(shared_info);
   }
 
+  if (FLAG_harmony_function_tostring) {
+    return Handle<String>::cast(shared_info->GetSourceCodeHarmony());
+  }
+
   IncrementalStringBuilder builder(isolate);
   FunctionKind kind = shared_info->kind();
   if (!IsArrowFunction(kind)) {
@@ -13673,6 +13677,47 @@ Handle<Object> SharedFunctionInfo::GetSourceCode() {
       source, start_position(), end_position());
 }
 
+namespace {
+template <typename Char>
+Handle<Object> NormalizeLineTerminators(FlatStringReader* reader,
+                                        IncrementalStringBuilder* builder) {
+  for (int i = 0; i < reader->length(); i++) {
+    Char c = reader->Get<Char>(i);
+    if (c == '\r') {
+      // normalize CR or CRLF
+      builder->AppendCharacter('\n');
+      if (i + 1 < reader->length() && reader->Get<Char>(i + 1) == '\n') {
+        // also consume the LF in the CRLF
+        i++;
+      }
+    } else {
+      builder->Append<Char, Char>(c);
+    }
+  }
+  return builder->Finish().ToHandleChecked();
+}
+}  // namespace
+
+Handle<Object> SharedFunctionInfo::GetSourceCodeHarmony() {
+  Isolate* isolate = GetIsolate();
+  if (!HasSourceCode()) return isolate->factory()->undefined_value();
+  Handle<String> script_source(String::cast(Script::cast(script())->source()));
+  int start_pos = function_token_position();
+  if (start_pos == kNoSourcePosition) start_pos = start_position();
+  Handle<String> function_source = isolate->factory()->NewSubString(
+      script_source, start_pos, end_position());
+  // normalize line terminators
+  FlatStringReader reader(isolate, function_source);
+  // TODO(jwolfe): we know the upper bound on the build is reader.length(). how
+  // to specify it?

[jwolfe, 2016/11/01 21:34:19]

this is an optional optimization we may want to do.

+  IncrementalStringBuilder builder(isolate);
+  if (function_source->IsOneByteRepresentationUnderneath()) {
+    return NormalizeLineTerminators<uint8_t>(&reader, &builder);
+  } else {
+    builder.ChangeEncoding();
+    return NormalizeLineTerminators<uc16>(&reader, &builder);
+  }
+}
 
 bool SharedFunctionInfo::IsInlineable() {
   // Check that the function has a script associated with it.