Add comments about lazy parsing and lazy compilation.

src/preparser.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1305 matching lines @@
       dupe_error_loc = scanner()->location();
     }
 
     done = (peek() == Token::RPAREN);
     if (!done) {
       Expect(Token::COMMA, CHECK_OK);
     }
   }
   Expect(Token::RPAREN, CHECK_OK);
 
-  // Determine if the function will be lazily compiled.
-  // Currently only happens to top-level functions.
-  // Optimistically assume that all top-level functions are lazily compiled.
-  bool is_lazily_compiled = (outer_scope_type == GLOBAL_SCOPE &&
-                             !inside_with && allow_lazy() &&
-                             !parenthesized_function_);
+  // See Parser::ParseFunctionLiteral for more information about lazy parsing
+  // and lazy compilation.
+  bool is_lazily_parsed = (outer_scope_type == GLOBAL_SCOPE &&
+                           !inside_with && allow_lazy() &&
+                           !parenthesized_function_);
   parenthesized_function_ = false;
 
   Expect(Token::LBRACE, CHECK_OK);
-  if (is_lazily_compiled) {
+  if (is_lazily_parsed) {
     ParseLazyFunctionLiteralBody(CHECK_OK);
   } else {
     ParseSourceElements(Token::RBRACE, ok);
   }
   Expect(Token::RBRACE, CHECK_OK);
 
   // Validate strict mode. We can do this only after parsing the function,
   // since the function can declare itself strict.
   if (!scope_->is_classic_mode()) {
     if (function_name.IsEvalOrArguments()) {
@@ skipping 70 matching lines @@
   int identifier_pos = position();
   if (scanner()->is_literal_ascii()) {
     log_->LogAsciiSymbol(identifier_pos, scanner()->literal_ascii_string());
   } else {
     log_->LogUtf16Symbol(identifier_pos, scanner()->literal_utf16_string());
   }
 }
 
 
 } }  // v8::internal