Handle "//# sourceURL" comments in the Parser instead of the JS.

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 369a451f350c543e3c193a5a332eb8c9e8fef0f0..c65766df77fb88a2afa9d626142697299dcff9a8 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -891,6 +891,9 @@ FunctionLiteral* Parser::DoParseProgram(CompilationInfo* info,
     bool ok = true;
     int beg_pos = scanner()->location().beg_pos;
     ParseSourceElements(body, Token::EOS, info->is_eval(), true, &ok);
+
+    if (scanner()->HasSourceMapComment()) ParseSourceMapComment();
+
     if (ok && strict_mode() == STRICT) {
       CheckOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
     }
@@ -3835,6 +3838,51 @@ void Parser::RegisterTargetUse(Label* target, Target* stop) {
 }
 
 
+void Parser::ParseSourceMapComment() {
+  Handle<String> source_map_comment =
+      scanner()->AllocateInternalizedSourceMapComment(isolate());
+  int value_start = 0, value_end = 0;
+  {
+    DisallowHeapAllocation no_gc;  // flat_data needs to stay alive.
+    String::FlatContent flat_data = source_map_comment->GetFlatContent();
+    if (!flat_data.IsAscii())
+      return;
+    Vector<const uint8_t> data = flat_data.ToOneByteVector();
+    // Parse the following: \s*name\s*=\s*value\s*.*
+    int name_start = 0;
+    while (name_start < data.length() && data[name_start] == ' ') {
+      ++name_start;
+    }
+    int name_end = name_start;
+    while (name_end < data.length() && data[name_end] != ' ' &&
+           data[name_end] != '=') {
+      ++name_end;
+    }
+    value_start = name_end;
+    while (value_start < data.length() && data[value_start] == ' ') {
+      ++value_start;
+    }
+    if (value_start >= data.length() || data[value_start] != '=') {
+      return;
+    }
+    ++value_start;  // Skip '='
+    while (value_start < data.length() && data[value_start] == ' ') {
+      ++value_start;
+    }
+    value_end = value_start;
+    while (value_end < data.length() && data[value_end] != ' ') {
+      ++value_end;
+    }
+    Vector<const uint8_t> name = data.SubVector(name_start, name_end);
+    if (!name.IsEqualTo(STATIC_ASCII_VECTOR("sourceURL"))) {
+      return;
+    }
+  }
+  info_->script()->set_source_url(*(isolate()->factory()->NewSubString(
+      source_map_comment, value_start, value_end)));
+}
+
+
 void Parser::ThrowPendingError() {
   if (has_pending_error_) {
     MessageLocation location(script_,