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

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 959e15514976132c32a0292e367ba17ea3b23d5e..08fd0e2d13b90cbc1a2e77314dc20ae96849e200 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -445,6 +445,8 @@ void BytecodeGenerator::VisitBlock(Block* stmt) {
 
 
 void BytecodeGenerator::VisitVariableDeclaration(VariableDeclaration* decl) {
+  RegisterAllocationScope register_scope(this);

[rmcilroy, 2016/01/15 14:17:20]

Instead of adding these, could you instead modify VisitDeclarations such that
you replace the line: AstVisitor::VisitDeclarations() with the following:

for (int i = 0; i < declarations->length(); i++) {
  RegisterAllocationScope register_scope(this);
  Visit(declarations->at(i));
}

Thanks.

[mythria, 2016/01/15 17:10:36]

Done.

+
   Variable* variable = decl->proxy()->var();
   VariableMode mode = decl->mode();
   // Const and let variables are initialized with the hole so that we can
@@ -480,14 +482,38 @@ void BytecodeGenerator::VisitVariableDeclaration(VariableDeclaration* decl) {
                                                   variable->index());
       }
       break;
-    case VariableLocation::LOOKUP:
-      UNIMPLEMENTED();
+    case VariableLocation::LOOKUP: {
+      DCHECK(IsDeclaredVariableMode(mode));
+
+      register_allocator()->PrepareForConsecutiveAllocations(3);
+      Register name = register_allocator()->NextConsecutiveRegister();
+      Register init_value = register_allocator()->NextConsecutiveRegister();
+      Register attributes = register_allocator()->NextConsecutiveRegister();
+
+      builder()->LoadLiteral(variable->name()).StoreAccumulatorInRegister(name);
+      if (hole_init) {
+        builder()->LoadTheHole().StoreAccumulatorInRegister(init_value);
+      } else {
+        // For variables, we must not use an initial value (such as 'undefined')
+        // because we may have a (legal) redeclaration and we must not destroy
+        // the current value.
+        builder()
+            ->LoadLiteral(Smi::FromInt(0))
+            .StoreAccumulatorInRegister(init_value);
+      }
+      builder()
+          ->LoadLiteral(Smi::FromInt(variable->DeclarationPropertyAttributes()))
+          .StoreAccumulatorInRegister(attributes)
+          .CallRuntime(Runtime::kDeclareLookupSlot, name, 3);
       break;
+    }
   }
 }
 
 
 void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
+  RegisterAllocationScope register_scope(this);

[rmcilroy, 2016/01/15 14:17:20]

Also remove this once the above comment is done.

[mythria, 2016/01/15 17:10:36]

Done.

+
   Variable* variable = decl->proxy()->var();
   switch (variable->location()) {
     case VariableLocation::GLOBAL:
@@ -513,8 +539,20 @@ void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
                                   variable->index());
       break;
     }
-    case VariableLocation::LOOKUP:
-      UNIMPLEMENTED();
+    case VariableLocation::LOOKUP: {
+      register_allocator()->PrepareForConsecutiveAllocations(3);
+      Register name = register_allocator()->NextConsecutiveRegister();
+      Register literal = register_allocator()->NextConsecutiveRegister();
+      Register attributes = register_allocator()->NextConsecutiveRegister();
+      builder()->LoadLiteral(variable->name()).StoreAccumulatorInRegister(name);
+
+      VisitForAccumulatorValue(decl->fun());
+      builder()
+          ->StoreAccumulatorInRegister(literal)
+          .LoadLiteral(Smi::FromInt(variable->DeclarationPropertyAttributes()))
+          .StoreAccumulatorInRegister(attributes)
+          .CallRuntime(Runtime::kDeclareLookupSlot, name, 3);
+    }
   }
 }
 
@@ -1319,6 +1357,8 @@ void BytecodeGenerator::VisitVariableAssignment(Variable* variable,
       break;
     }
     case VariableLocation::LOOKUP: {
+      // TODO(mythria): Use Runtime::kInitializeLegacyConstLookupSlot for
+      // initializations of const declarations.
       builder()->StoreLookupSlot(variable->name(), language_mode());
       break;
     }
@@ -1559,7 +1599,7 @@ void BytecodeGenerator::VisitCall(Call* expr) {
         DCHECK(Register::AreContiguous(callee, receiver));
         Variable* variable = callee_expr->AsVariableProxy()->var();
         builder()
-            ->MoveRegister(Register::function_context(), context)
+            ->MoveRegister(execution_context()->reg(), context)
             .LoadLiteral(variable->name())
             .StoreAccumulatorInRegister(name)
             .CallRuntimeForPair(Runtime::kLoadLookupSlot, context, 2, callee);