X87: Clean up and update const / var

port r22379

original commit message:
This CL simplifies var / const by ensuring the behavior is consistent in itself,
and with regular JS semantics; between regular var/const and eval-ed var/const.

Legacy const is changed so that a declaration declares a configurable, but non-writable, slot,
 and the initializer reconfigures it (when possible) to non-configurable non-writable. This
 avoids the need for "the hole" as marker value in JSContextExtensionObjects and GlobalObjects.
Undefined is used instead.

BUG=
R=weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/397573002

Patch from Chunyang Dai <chunyang.dai@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22395 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x87/full-codegen-x87.cc

@@ -801,7 +801,7 @@ void FullCodeGenerator::VisitVariableDeclaration(
       } else {
         __ push(Immediate(Smi::FromInt(0)));  // Indicates no initial value.
       }
-      __ CallRuntime(Runtime::kDeclareContextSlot, 4);
+      __ CallRuntime(Runtime::kDeclareLookupSlot, 4);
       break;
     }
   }
@@ -853,7 +853,7 @@ void FullCodeGenerator::VisitFunctionDeclaration(
       __ push(Immediate(variable->name()));
       __ push(Immediate(Smi::FromInt(NONE)));
       VisitForStackValue(declaration->fun());
-      __ CallRuntime(Runtime::kDeclareContextSlot, 4);
+      __ CallRuntime(Runtime::kDeclareLookupSlot, 4);
       break;
     }
   }
@@ -2379,16 +2379,6 @@ void FullCodeGenerator::EmitStoreToStackLocalOrContextSlot(
 }
 
 
-void FullCodeGenerator::EmitCallStoreContextSlot(
-    Handle<String> name, StrictMode strict_mode) {
-  __ push(eax);  // Value.
-  __ push(esi);  // Context.
-  __ push(Immediate(name));
-  __ push(Immediate(Smi::FromInt(strict_mode)));
-  __ CallRuntime(Runtime::kStoreContextSlot, 4);
-}
-
-
 void FullCodeGenerator::EmitVariableAssignment(Variable* var,
                                                Token::Value op) {
   if (var->IsUnallocated()) {
@@ -2404,7 +2394,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var,
       __ push(eax);
       __ push(esi);
       __ push(Immediate(var->name()));
-      __ CallRuntime(Runtime::kInitializeConstContextSlot, 3);
+      __ CallRuntime(Runtime::kInitializeLegacyConstLookupSlot, 3);
     } else {
       ASSERT(var->IsStackLocal() || var->IsContextSlot());
       Label skip;
@@ -2418,27 +2408,29 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var,
 
   } else if (var->mode() == LET && op != Token::INIT_LET) {
     // Non-initializing assignment to let variable needs a write barrier.
-    if (var->IsLookupSlot()) {
-      EmitCallStoreContextSlot(var->name(), strict_mode());
-    } else {
-      ASSERT(var->IsStackAllocated() || var->IsContextSlot());
-      Label assign;
-      MemOperand location = VarOperand(var, ecx);
-      __ mov(edx, location);
-      __ cmp(edx, isolate()->factory()->the_hole_value());
-      __ j(not_equal, &assign, Label::kNear);
-      __ push(Immediate(var->name()));
-      __ CallRuntime(Runtime::kThrowReferenceError, 1);
-      __ bind(&assign);
-      EmitStoreToStackLocalOrContextSlot(var, location);
-    }
+    ASSERT(!var->IsLookupSlot());
+    ASSERT(var->IsStackAllocated() || var->IsContextSlot());
+    Label assign;
+    MemOperand location = VarOperand(var, ecx);
+    __ mov(edx, location);
+    __ cmp(edx, isolate()->factory()->the_hole_value());
+    __ j(not_equal, &assign, Label::kNear);
+    __ push(Immediate(var->name()));
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&assign);
+    EmitStoreToStackLocalOrContextSlot(var, location);
 
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
-    // Assignment to var or initializing assignment to let/const
-    // in harmony mode.
     if (var->IsLookupSlot()) {
-      EmitCallStoreContextSlot(var->name(), strict_mode());
+      // Assignment to var.
+      __ push(eax);  // Value.
+      __ push(esi);  // Context.
+      __ push(Immediate(var->name()));
+      __ push(Immediate(Smi::FromInt(strict_mode())));
+      __ CallRuntime(Runtime::kStoreLookupSlot, 4);
     } else {
+      // Assignment to var or initializing assignment to let/const in harmony
+      // mode.
       ASSERT(var->IsStackAllocated() || var->IsContextSlot());
       MemOperand location = VarOperand(var, ecx);
       if (generate_debug_code_ && op == Token::INIT_LET) {