[Interpreter] Adds support for variable/function declarations in lookup slots.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/control-flow-builders.h"
 #include "src/objects.h"
@@ skipping 545 matching lines @@
         Register destination(builder()->Parameter(variable->index() + 1));
         builder()->LoadTheHole().StoreAccumulatorInRegister(destination);
       }
       break;
     case VariableLocation::CONTEXT:
       if (hole_init) {
         builder()->LoadTheHole().StoreContextSlot(execution_context()->reg(),
                                                   variable->index());
       }
       break;
-    case VariableLocation::LOOKUP:
-      UNIMPLEMENTED();
+    case VariableLocation::LOOKUP: {
+      TemporaryRegisterScope temporary_register_scope(builder());

[rmcilroy, 2016/01/14 11:21:12]

Please don't use TemporaryRegisterScope (it is going away anyway) - you should
just need to use execution_result()->NewRegister() since the execution result
has it's own register allocation scope for the expression visitor.

[mythria, 2016/01/15 11:27:04]

Done.

+      temporary_register_scope.PrepareForConsecutiveAllocations(3);
+      DCHECK(IsDeclaredVariableMode(mode));

[rmcilroy, 2016/01/14 11:21:12]

nit - move to the top of the case

[mythria, 2016/01/15 11:27:04]

Done.

+      Register name = temporary_register_scope.NextConsecutiveRegister();
+      Register init_value = temporary_register_scope.NextConsecutiveRegister();
+      Register attributes = temporary_register_scope.NextConsecutiveRegister();
+      builder()->LoadLiteral(variable->name()).StoreAccumulatorInRegister(name);

[rmcilroy, 2016/01/14 11:21:12]

nit - newline abovem, and newline between LoadLiteral and StoreAccumulator...

[mythria, 2016/01/15 11:27:04]

I am not sure, I understood this correctly. cl format puts LoadLiteral and
StoreAccumulator in the same line.  

+      if (hole_init) {
+        builder()->LoadTheHole().StoreAccumulatorInRegister(init_value);

[rmcilroy, 2016/01/14 11:21:12]

ditto

+      } else {
+        builder()
+            ->LoadLiteral(Smi::FromInt(0))

[rmcilroy, 2016/01/14 11:21:12]

Add comment that this indicates no initial value and why this should not be
undefined (like fullcodegen). 

[mythria, 2016/01/15 11:27:04]

Done.

+            .StoreAccumulatorInRegister(init_value);
+      }
+      builder()
+          ->LoadLiteral(Smi::FromInt(variable->DeclarationPropertyAttributes()))
+          .StoreAccumulatorInRegister(attributes);
+      builder()->CallRuntime(Runtime::kDeclareLookupSlot, name, 3);

[rmcilroy, 2016/01/14 11:21:12]

nit - no need for builder() here

[mythria, 2016/01/15 11:27:04]

Done.

       break;
+    }
   }
 }
 
 
 void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
   Variable* variable = decl->proxy()->var();
   switch (variable->location()) {
     case VariableLocation::GLOBAL:
     case VariableLocation::UNALLOCATED: {
       Handle<SharedFunctionInfo> function = Compiler::GetSharedFunctionInfo(
@@ skipping 10 matching lines @@
       VisitVariableAssignment(variable, FeedbackVectorSlot::Invalid());
       break;
     }
     case VariableLocation::CONTEXT: {
       DCHECK_EQ(0, execution_context()->ContextChainDepth(variable->scope()));
       VisitForAccumulatorValue(decl->fun());
       builder()->StoreContextSlot(execution_context()->reg(),
                                   variable->index());
       break;
     }
-    case VariableLocation::LOOKUP:
-      UNIMPLEMENTED();
+    case VariableLocation::LOOKUP: {
+      TemporaryRegisterScope temporary_register_scope(builder());
+      temporary_register_scope.PrepareForConsecutiveAllocations(3);
+      Register name = temporary_register_scope.NextConsecutiveRegister();
+      Register literal = temporary_register_scope.NextConsecutiveRegister();
+      Register attributes = temporary_register_scope.NextConsecutiveRegister();
+      builder()->LoadLiteral(variable->name()).StoreAccumulatorInRegister(name);

[rmcilroy, 2016/01/14 11:21:12]

newline

[mythria, 2016/01/15 11:27:04]

Done.

+      VisitForAccumulatorValue(decl->fun());
+      builder()->StoreAccumulatorInRegister(literal);
+      builder()
+          ->LoadLiteral(Smi::FromInt(variable->DeclarationPropertyAttributes()))
+          .StoreAccumulatorInRegister(attributes);
+      builder()->CallRuntime(Runtime::kDeclareLookupSlot, name, 3);

[rmcilroy, 2016/01/14 11:21:12]

only one builder() for these 5 lines

[mythria, 2016/01/15 11:27:04]

Done.

+    }
   }
 }
 
 
 void BytecodeGenerator::VisitImportDeclaration(ImportDeclaration* decl) {
   UNIMPLEMENTED();
 }
 
 
 void BytecodeGenerator::VisitExportDeclaration(ExportDeclaration* decl) {
@@ skipping 791 matching lines @@
           builder()
               ->LoadContextSlot(context_reg, Context::PREVIOUS_INDEX)
               .StoreAccumulatorInRegister(context_reg);
         }
         builder()->LoadAccumulatorWithRegister(value_temp);
       }
       builder()->StoreContextSlot(context_reg, variable->index());
       break;
     }
     case VariableLocation::LOOKUP: {
+      // TODO(mythria): Use Runtime::kInitializeLegacyConstLookupSlot for
+      // initializations of const declarations.

[mythria, 2016/01/13 17:27:21]

This is not related to this cl. I should have added this earlier. I can move
this to a different cl but that would be just a TODO. I was not sure which is
better.

       builder()->StoreLookupSlot(variable->name(), language_mode());
       break;
     }
   }
 }
 
 
 void BytecodeGenerator::VisitAssignment(Assignment* expr) {
   DCHECK(expr->target()->IsValidReferenceExpression());
   Register object, key;
@@ skipping 859 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8