Revert "Revert "Fix a bug in scope analysis.""

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 3bfc94fbd1ac9392d0e2f42726cc5cf4b13882ab..ed6ff493133e54de3a27a2a267a5f2198b0e69e7 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -3641,7 +3641,10 @@ FunctionLiteral* Parser::ParseFunctionLiteral(Handle<String> var_name,
   }
 
   int num_parameters = 0;
-  Scope* scope = NewScope(top_scope_, Scope::FUNCTION_SCOPE, inside_with());
+  // Function declarations are hoisted.
+  Scope* scope = (type == DECLARATION)
+      ? NewScope(top_scope_->DeclarationScope(), Scope::FUNCTION_SCOPE, false)
+      : NewScope(top_scope_, Scope::FUNCTION_SCOPE, inside_with());
   ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(8);
   int materialized_literal_count;
   int expected_property_count;
@@ -3715,36 +3718,43 @@ FunctionLiteral* Parser::ParseFunctionLiteral(Handle<String> var_name,
                                  RelocInfo::kNoPosition)));
     }
 
-    // Determine if the function will be lazily compiled. The mode can
-    // only be PARSE_LAZILY if the --lazy flag is true.
+    // Determine if the function will be lazily compiled. The mode can only
+    // be PARSE_LAZILY if the --lazy flag is true.  We will not lazily
+    // compile if we do not have preparser data for the function.
     bool is_lazily_compiled = (mode() == PARSE_LAZILY &&
                                top_scope_->outer_scope()->is_global_scope() &&
                                top_scope_->HasTrivialOuterContext() &&
-                               !parenthesized_function_);
+                               !parenthesized_function_ &&
+                               pre_data() != NULL);
     parenthesized_function_ = false;  // The bit was set for this function only.
 
-    int function_block_pos = scanner().location().beg_pos;
-    if (is_lazily_compiled && pre_data() != NULL) {
+    if (is_lazily_compiled) {
+      int function_block_pos = scanner().location().beg_pos;
       FunctionEntry entry = pre_data()->GetFunctionEntry(function_block_pos);
       if (!entry.is_valid()) {
-        ReportInvalidPreparseData(name, CHECK_OK);
-      }
-      end_pos = entry.end_pos();
-      if (end_pos <= function_block_pos) {
-        // End position greater than end of stream is safe, and hard to check.
-        ReportInvalidPreparseData(name, CHECK_OK);
+        // There is no preparser data for the function, we will not lazily
+        // compile after all.
+        is_lazily_compiled = false;

[Lasse Reichstein, 2011/08/03 09:05:17]

This handles false positives (from the parser's perspective) only. It also
affects false negatives, if they can occur.  It will completely block all
further laziness, since the ScriptDataImpl will never match (and thereby skip)
the unused function entry.

That's probably fine for now.

[Kevin Millikin (Chromium), 2011/08/03 09:09:49]

Thanks for pointing that out, I hadn't realized it.  I want to commit this as
is, but we should clean it up soon.

+      } else {
+        end_pos = entry.end_pos();
+        if (end_pos <= function_block_pos) {
+          // End position greater than end of stream is safe, and hard to check.
+          ReportInvalidPreparseData(name, CHECK_OK);
+        }
+        isolate()->counters()->total_preparse_skipped()->Increment(
+            end_pos - function_block_pos);
+        // Seek to position just before terminal '}'.
+        scanner().SeekForward(end_pos - 1);
+        materialized_literal_count = entry.literal_count();
+        expected_property_count = entry.property_count();
+        if (entry.strict_mode()) top_scope_->EnableStrictMode();
+        only_simple_this_property_assignments = false;
+        this_property_assignments = isolate()->factory()->empty_fixed_array();
+        Expect(Token::RBRACE, CHECK_OK);
       }
-      isolate()->counters()->total_preparse_skipped()->Increment(
-          end_pos - function_block_pos);
-      // Seek to position just before terminal '}'.
-      scanner().SeekForward(end_pos - 1);
-      materialized_literal_count = entry.literal_count();
-      expected_property_count = entry.property_count();
-      if (entry.strict_mode()) top_scope_->EnableStrictMode();
-      only_simple_this_property_assignments = false;
-      this_property_assignments = isolate()->factory()->empty_fixed_array();
-      Expect(Token::RBRACE, CHECK_OK);
-    } else {
+    }
+
+    if (!is_lazily_compiled) {
       ParseSourceElements(body, Token::RBRACE, CHECK_OK);
 
       materialized_literal_count = lexical_scope.materialized_literal_count();