Stack allocate lexical locals + hoist stack slots

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/js-type-feedback.h"
@@ skipping 1004 matching lines @@
 
 void AstGraphBuilder::VisitBlock(Block* stmt) {
   BlockBuilder block(this);
   ControlScopeForBreakable scope(this, stmt, &block);
   if (stmt->labels() != NULL) block.BeginBlock();
   if (stmt->scope() == NULL) {
     // Visit statements in the same scope, no declarations.
     VisitStatements(stmt->statements());
   } else {
     // Visit declarations and statements in a block scope.
-    Node* context = BuildLocalBlockContext(stmt->scope());
-    ContextScope scope(this, stmt->scope(), context);
-    VisitDeclarations(stmt->scope()->declarations());
-    VisitStatements(stmt->statements());
+    if (stmt->scope()->ContextLocalCount() > 0) {
+      Node* context = BuildLocalBlockContext(stmt->scope());
+      ContextScope scope(this, stmt->scope(), context);
+      VisitDeclarations(stmt->scope()->declarations());
+      VisitStatements(stmt->statements());
+    } else {
+      VisitDeclarations(stmt->scope()->declarations());
+      VisitStatements(stmt->statements());
+    }
   }
   if (stmt->labels() != NULL) block.EndBlock();
 }
 
 
 void AstGraphBuilder::VisitModuleStatement(ModuleStatement* stmt) {
   UNREACHABLE();
 }
 
 
@@ skipping 434 matching lines @@
   ast_context()->ProduceValue(value);
 }
 
 
 void AstGraphBuilder::VisitClassLiteral(ClassLiteral* expr) {
   if (expr->scope() == NULL) {
     // Visit class literal in the same scope, no declarations.
     VisitClassLiteralContents(expr);
   } else {
     // Visit declarations and class literal in a block scope.
-    Node* context = BuildLocalBlockContext(expr->scope());
-    ContextScope scope(this, expr->scope(), context);
-    VisitDeclarations(expr->scope()->declarations());
-    VisitClassLiteralContents(expr);
+    if (expr->scope()->ContextLocalCount() > 0) {
+      Node* context = BuildLocalBlockContext(expr->scope());
+      ContextScope scope(this, expr->scope(), context);
+      VisitDeclarations(expr->scope()->declarations());
+      VisitClassLiteralContents(expr);
+    } else {
+      VisitDeclarations(expr->scope()->declarations());
+      VisitClassLiteralContents(expr);
+    }
   }
 }
 
 
 void AstGraphBuilder::VisitClassLiteralContents(ClassLiteral* expr) {
   Node* class_name = expr->raw_name() ? jsgraph()->Constant(expr->name())
                                       : jsgraph()->UndefinedConstant();
 
   // The class name is expected on the operand stack.
   environment()->Push(class_name);
@@ skipping 2070 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8