Getting rid of ExitContextStatement for scoped blocks.

Review URL: http://codereview.chromium.org/7835027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9158 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/full-codegen.cc

@@ -855,6 +855,7 @@ void FullCodeGenerator::VisitBlock(Block* stmt) {
   SetStatementPosition(stmt);
 
   Scope* saved_scope = scope();
+  // Push a block context when entering a block with block scoped variables.
   if (stmt->block_scope() != NULL) {
     { Comment cmnt(masm_, "[ Extend block context");
       scope_ = stmt->block_scope();
@@ -873,6 +874,14 @@ void FullCodeGenerator::VisitBlock(Block* stmt) {
   scope_ = saved_scope;
   __ bind(nested_block.break_label());
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
+
+  // Pop block context if necessary.
+  if (stmt->block_scope() != NULL) {
+    LoadContextField(context_register(), Context::PREVIOUS_INDEX);
+    // Update local stack frame context field.
+    StoreToFrameField(StandardFrameConstants::kContextOffset,
+                      context_register());
+  }
 }
 
 

src/parser.cc

@@ -1586,16 +1586,7 @@ Block* Parser::ParseScopedBlock(ZoneStringList* labels, bool* ok) {
 
   block_scope = block_scope->FinalizeBlockScope();
   body->set_block_scope(block_scope);
-
-  if (block_scope != NULL) {
-    // 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());
-    return exit;
-  } else {
-    return body;
-  }
+  return body;
 }
 
 

test/mjsunit/harmony/debug-blockscopes.js

@@ -437,28 +437,6 @@ with_block_5();
 EndTest();
 
 
-// With block and a block local variable.
-BeginTest("With block 5");
-
-function with_block_5() {
-  with({a:1}) {
-    let a = 2;
-    debugger;
-  }
-}
-
-listener_delegate = function(exec_state) {
-  CheckScopeChain([debug.ScopeType.Block,
-                   debug.ScopeType.With,
-                   debug.ScopeType.Local,
-                   debug.ScopeType.Global], exec_state);
-  CheckScopeContent({a:2}, 0, exec_state);
-  CheckScopeContent({a:1}, 1, exec_state);
-};
-with_block_5();
-EndTest();
-
-
 // Simple closure formed by returning an inner function referering to an outer
 // block local variable and an outer function's parameter.
 BeginTest("Closure 1");