Simplfy handling of exits from scoped blocks.

src/parser.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 1569 matching lines @@
       }
     }
   }
   Expect(Token::RBRACE, CHECK_OK);
   top_scope_ = saved_scope;
 
   block_scope = block_scope->FinalizeBlockScope();
   body->set_block_scope(block_scope);
 
   if (block_scope != NULL) {
-    // Create exit block.
-    Block* exit = new(zone()) Block(isolate(), NULL, 1, false);
+    // Rewrite the block { B } to a block: { { B } ExitContext; }
+    Block* exit = new(zone()) Block(isolate(), NULL, 2, false);
+    exit->AddStatement(body);
     exit->AddStatement(new(zone()) ExitContextStatement());

[Kevin Millikin (Chromium), 2011/09/02 15:17:44]

Now we're no longer making essential use of ExitContextStatement (it's
completely predictable where it will occur).

As a next change, can you get rid of it?  'With' already makes do without it by
compiling the code implicitly at the end of the body.  Catch and blocks with
scopes could do the same.

[Steven, 2011/09/05 08:54:50]

Will do it.
On 2011/09/02 15:17:44, Kevin Millikin wrote:

-
-    // Create a try-finally statement.
-    TryFinallyStatement* try_finally =
-        new(zone()) TryFinallyStatement(body, exit);
-    try_finally->set_escaping_targets(collector.targets());
-
-    // Create a result block.
-    Block* result = new(zone()) Block(isolate(), NULL, 1, false);
-    result->AddStatement(try_finally);
-    return result;
+    return exit;
   } else {
     return body;
   }
 }
 
 
 Block* Parser::ParseVariableStatement(VariableDeclarationContext var_context,
                                       bool* ok) {
   // VariableStatement ::
   //   VariableDeclarations ';'
@@ skipping 3630 matching lines @@
       result = parser.ParseProgram(source,
                                    info->is_global(),
                                    info->StrictMode());
     }
   }
   info->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal