From 2ed9e6e634dc46a08f1da2eebef82e3e563d6e72 Mon Sep 17 00:00:00 2001
From: verwaest <verwaest@chromium.org>
Date: Mon, 8 Aug 2016 04:51:27 -0700
Subject: [PATCH] Only conditionally add inner scope when deserializing

BUG=v8:5209

Review-Url: https://codereview.chromium.org/2224793003
Cr-Commit-Position: refs/heads/master@{#38436}
---
 src/ast/scopes.cc | 12 ++++++------
 src/ast/scopes.h  |  8 +++-----
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/ast/scopes.cc b/src/ast/scopes.cc
index 0c19dd63a8..2acf68f5e3 100644
--- a/src/ast/scopes.cc
+++ b/src/ast/scopes.cc
@@ -140,7 +140,7 @@ Scope::Scope(Zone* zone, Scope* inner_scope, ScopeType scope_type,
   // Ensure at least MIN_CONTEXT_SLOTS to indicate a materialized context.
   num_heap_slots_ = Max(num_heap_slots_,
                         static_cast<int>(Context::MIN_CONTEXT_SLOTS));
-  AddInnerScope(inner_scope);
+  if (inner_scope != nullptr) AddInnerScope(inner_scope);
 }
 
 DeclarationScope::DeclarationScope(Zone* zone, Scope* inner_scope,
@@ -165,7 +165,7 @@ Scope::Scope(Zone* zone, Scope* inner_scope,
       scope_type_(CATCH_SCOPE),
       already_resolved_(true) {
   SetDefaults();
-  AddInnerScope(inner_scope);
+  if (inner_scope != nullptr) AddInnerScope(inner_scope);
   num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
   Variable* variable =
       variables_.Declare(zone, this, catch_variable_name, VAR, Variable::NORMAL,
@@ -232,8 +232,8 @@ Scope* Scope::DeserializeScopeChain(Isolate* isolate, Zone* zone,
                                     AstValueFactory* ast_value_factory,
                                     DeserializationMode deserialization_mode) {
   // Reconstruct the outer scope chain from a closure's context chain.
-  Scope* current_scope = NULL;
-  Scope* innermost_scope = NULL;
+  Scope* current_scope = nullptr;
+  Scope* innermost_scope = nullptr;
   while (!context->IsNativeContext()) {
     if (context->IsWithContext() || context->IsDebugEvaluateContext()) {
       // For scope analysis, debug-evaluate is equivalent to a with scope.
@@ -241,7 +241,7 @@ Scope* Scope::DeserializeScopeChain(Isolate* isolate, Zone* zone,
           Scope(zone, current_scope, WITH_SCOPE, Handle<ScopeInfo>::null());
       current_scope = with_scope;
       // All the inner scopes are inside a with.
-      for (Scope* s = innermost_scope; s != NULL; s = s->outer_scope()) {
+      for (Scope* s = innermost_scope; s != nullptr; s = s->outer_scope()) {
         s->scope_inside_with_ = true;
       }
     } else if (context->IsScriptContext()) {
@@ -273,7 +273,7 @@ Scope* Scope::DeserializeScopeChain(Isolate* isolate, Zone* zone,
     if (deserialization_mode == DeserializationMode::kDeserializeOffHeap) {
       current_scope->DeserializeScopeInfo(isolate, ast_value_factory);
     }
-    if (innermost_scope == NULL) innermost_scope = current_scope;
+    if (innermost_scope == nullptr) innermost_scope = current_scope;
     context = context->previous();
   }
 
diff --git a/src/ast/scopes.h b/src/ast/scopes.h
index 68ceb191f8..5be698fc10 100644
--- a/src/ast/scopes.h
+++ b/src/ast/scopes.h
@@ -622,11 +622,9 @@ class Scope: public ZoneObject {
         const AstRawString* catch_variable_name);
 
   void AddInnerScope(Scope* inner_scope) {
-    if (inner_scope != nullptr) {
-      inner_scope->sibling_ = inner_scope_;
-      inner_scope_ = inner_scope;
-      inner_scope->outer_scope_ = this;
-    }
+    inner_scope->sibling_ = inner_scope_;
+    inner_scope_ = inner_scope;
+    inner_scope->outer_scope_ = this;
   }
 
   void RemoveInnerScope(Scope* inner_scope) {